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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 433 (1998), S. 443-447 
    ISSN: 1432-2307
    Schlagwort(e): Key words Apoptosis ; Crescent-shaped spaces ; Ultrastructure ; Nivalenol ; Thymus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  There have been many reports on the formation of apoptotic bodies, but little is known about the cellular pathological processes and the morphological changes involved. We induced apoptotic cell death by administering nivalenol (NIV), a trichothecene mycotoxin produced by Fusarium species, and investigated the ultrastructural process of formation of apoptotic bodies. The thymus was examined by electron microscopy 6, 12, and 18 h after administration. Apoptotic cell death was induced in the thymus of NIV-treated mice. The nuclei became invaginated and pinched off to give fragments, and crescent-shaped spaces (CSS) were found around the nuclear envelopes of these cells at quite an early stage. In some of these spaces, myelin figures were observed. We divided the process of formation into four stages and characterized each of them. These are easily recognized in morphological stages and are also useful for clarifying the apoptotic mechanism.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 96 (1998), S. 97-101 
    ISSN: 1432-0533
    Schlagwort(e): Key words Brittany Spaniel dog ; Immunocytochemistry ; Purkinje cell ; Spinocerebellar degeneration ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Eight Brittany Spaniel dogs, seven females and one male, between 7 and 14 years old presented with clinical neurological signs of spinocerebellar disease of about 6 months to 4 years duration. Clinically the dogs had a dramatic forward “saluting” movement of the thoracic limbs, hypermetria of the pelvic limbs, cerebellar ataxia and intention tremors. Terminally, dogs crawled in a crouched thoracic posture with neck extension. Lesions were confined to cerebellum, medulla oblongata and spinal cord. The most severe lesion was diffuse Purkinje cell loss with massive neurofilament accumulation in degenerating cells. There was some bilateral neuronal degeneration in the dorsal horns of the spinal cord and in the gracilis and cuneate nuclei. There was bilateral sporadic axonal degeneration in the dorsal columns and lateral and ventromedial areas of the spinal cord. The etiology of this syndrome was not determined.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 95 (1998), S. 367-372 
    ISSN: 1432-0533
    Schlagwort(e): Key words Amyotrophic lateral sclerosis ; Heterotopic neuron ; Alpha motor neuron ; Immunocytochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This report concerns a comparative immunocytochemical, ultrastructural and morphometric investigation on heterotopic neurons in the white matter of the spinal cords of 19 patients with amyotrophic lateral sclerosis (ALS) and 18 age-matched neurologically normal individuals. The study revealed that the heterotopic neurons were scattered in the white matter, often adjacent to gray matter, that they immunoreacted with the antibody to synaptophysin, and that there were synaptic apparatuses on the surface of their somata and their neuronal processes. Bunina bodies and ubiquitin-positive inclusions such as Lewy body-like inclusions and skein-like inclusions, characteristic of anterior horn neurons of ALS, were present in the cytoplasm of the patients’ heterotopic neurons in the anterior or lateral column of the white matter. These findings suggest that heterotopic neurons in the anterior or lateral column have the characteristics of alpha motor neurons. The average number of heterotopic neurons observed in ALS patients was generally less than in normal subjects. This reduction was correlated with the severity of neuronal loss. The heterotopic neurons in ALS were less susceptible to the degenerative process as compared with spinal cord anterior horn cells. We assume that in this disease the heterotopic neurons may be degenerated and their number diminished after or concomitantly with the depletion of anterior horn neurons.
    Materialart: Digitale Medien
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  • 4
    ISSN: 1432-0533
    Schlagwort(e): Key words Dentatorubral-pallidoluysian atrophy ; Nuclear inclusion ; Ubiquitin ; Immunohistochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We examined the brains and spinal cords of seven patients with clinicopathologically and genetically confirmed hereditary dentatorubral-pallidoluysian atrophy (DRPLA) using an antibody against ubiquitin, and found small, round immunoreactive intranuclear inclusions in both neurons and glial cells in various brain regions. Ubiquitinated neuronal intranuclear inclusions (uNIIs) were consistently found in the striatum, the pontine nuclei, the inferior olivary complex, the cerebellar cortex and the dentate nucleus. Ubiquitinated glial intranuclear inclusions (uGIIs) were found less frequently than uNIIs. Most of the inclusion-bearing nuclei were of an astrocytic nature. Immunostaining with an antibody against DRPLA protein revealed similar immunoreactive neuronal and glial intranuclear inclusions, but in much smaller in numbers compared with uNIIs and uGIIs. Electron microscopy showed that such inclusions were composed of granular and filamentous structures. These findings strongly suggest that, in DRPLA, the occurrence of uNIIs and uGIIs is directly related to the causative gene abnormality (an expanded CAG repeat encoding polyglutamine), that neurons are affected much more widely than previously recognized and that glial cells are also involved in the disease process.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1432-0533
    Schlagwort(e): Key words Congenital myopathy ; Muscle fibers ; Ultrastructure ; Myofibrillar disarray
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A 44-year-old man presenting with dyspnoic attacks was found to be affected with congenital myopathy, rigid spine, restrictive respiratory insufficiency and cardiomyopathy. Muscle biopsy showed type 1 fiber predominance (65.7%) and hypotrophy, and characteristic changes in 43.9% of the type 1 fibers, consisting in alternating pale and dark staining on alkaline ATPase reacted sections in a mosaic pattern. Ultrastructural examination demonstrated bands of myofibrils at right angles or skew to the remaining myofibrils transversing the fibers. Myofibrillar disarray was always associated with loss of the Z-discs and actin filaments, and often with aggregation of mitochondria. The muscle biopsy findings in this patient suggest a new entity of congenital myopathy with clinical features of rigid spine, cardiomyopathy and restrictive respiratory insufficiency, characterized by peculiar abnormalities of ATPase staining in a mosaic pattern and, ultrastructurally, by zones of disorientation of the sarcomeres.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1432-0568
    Schlagwort(e): Key words Adult-type Leydig cells ; Endothelium ; 3β-HSD ; Ultrastructure ; Differentiation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  In the biosynthesis of steroid hormones 3β-hydroxysteroid dehydrogenase (3β-HSD) is a key enzyme. The present report describes the subcellular localization of the enzyme in the fetal-type Leydig cells, the fibroblast-like precursors of adult-type Leydig cells and in endothelial cells of interstitial capillaries. Histochemical methods for light microscopy and ultracytochemical methods for electron microscopy were used on rat testes of postnatal day 15. 3β-HSD reactivity was located at subcellular levels by means of the ferricyanide method. A specific, distinct localization of reaction product in the form of copper ferrocyanide precipitates was observed on the membranes of the smooth endoplasmic reticulum not only in the fetal-type Leydig cells and the fibroblast-like precursors of adult-type Leydig cells, but also focally in the endothelial cells of interstitial blood capillaries. Topographically, the 3β-HSD-positive precursors were most often found in the outer layer of the boundary tissue and surrounding interstitial blood vessels. The capillaries with 3β-HSD-positive endothelial cells were usually located in the vicinity of 3β-HSD-positive Leydig cells. For the first time, 3β-HSD has been located at the subcellular level in precursors of adult-type Leydig cells and focally in capillary endothelial cells associated with them. Due to the close association between 3β-HSD-positive vascular endothelial cells and Leydig cells a paracrine relationship between the two cell types may be involved in the acute regulation of steroidogenesis by blood-borne luteinizing hormone.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1432-0533
    Schlagwort(e): Key words Anorexia nervosa ; Myopathy ; Muscle biopsy ; Ultrastructure ; Protein-energy malnutrition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Protein-energy malnutrition in anorexia nervosa is an under-recognised cause of muscle dysfunction. To characterise the skeletal myopathy that occurs in patients with severe anorexia nervosa, muscle function and structure were comprehensively examined in eight young adult female patients with severe (40%) self-induced weight loss. All of the patients showed impaired muscle function on strength and exercise measurement. The maximum voluntary contraction force for the patient group was significantly less than predicted values. Electromyography revealed myopathy in five of the patients, four of whom also had electro-physiological evidence of neuropathy. However, muscle biopsy specimens consistently showed myopathic changes with severe type 2 fibre atrophy but with no evidence of neuropathic changes. Ultrastructurally, there was separation and segmental loss of myofibrils and most biopsy samples contained abundant glycogen granules; we have previously reported that one of the most consistent biochemical abnormalities in these patients is impaired ischaemic lactate responses to forearm exercise. The result of severe protein-energy malnutrition on the musculo-skeletal system is a metabolic myopathy. Although the patients admitted to a variety of abnormal dieting behaviours, such as over-exercising and self-induced vomiting, no association was found between any of these and quantitative histological changes in the muscle biopsy samples. It is recommended that myopathy in anorexia nervosa be treated by instituting an appropriate refeeding programme.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 197 (1998), S. 135-141 
    ISSN: 1432-0568
    Schlagwort(e): Key words Interstitial cells of Cajal ; Ultrastructure ; Gap junction ; Intestine ; Motility
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Interstitial cells forming many large gap junctions in the region of the deep muscular plexus of the rat small intestine were studied by electron microscopy and by three-dimensional cell models reconstructed from serial ultrathin sections. Two different profiles of cells were observed. Cells of the first profile are characterized by an elongated cell shape and by less electron-dense cytoplasm, containing many mitochondria, well-developed Golgi apparatus and free ribosomes. They mainly connect with smooth muscle cells of the main circular layer. In a three-dimensional cell model, the total area of the gap junctions occupies 1.3% of the cell surface. Cells of the second profile are characterized by the frequent occurrence of slender cytoplasmic processes, higher electron-dense cytoplasm, containing mitochondria, Golgie apparatus and well-developed rough endoplasmic reticulum, and numerous caveolae on the cell membrane. In this cell model, gap junctions occupy 0.8% of the cell surface. The ratio of gap junctions with the same profile of cells to the total gap junction area is 37.7%, which is more than three times greater than the 9.9% in cells of the first profile. These cells were closely associated with nerve terminals. It is likely that these cells with different profiles constitute subtypes with each other and cooperate for regulation of intestinal motility via the transmission of nerve signals.
    Materialart: Digitale Medien
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  • 9
    ISSN: 1432-0533
    Schlagwort(e): Key words Congenital myopathy ; morphometry ; Ultrastructure ; Fetal myogenesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Centronuclear myopathy (CNM) is a congenital myopathy which manifests itself as a severe neonatal (also termed myotubular myopathy), early-onset, or adult form. The histological pattern of each is marked by a considerable number of nuclei of muscle fibers being internally placed. Owing to their remote resemblance to myotubes, and their expression of developmentally regulated proteins, most authors now favor the concept that myogenesis is arrested or delayed in this disease. We here present two muscle biopsy specimens of a patient with early-onset CNM, taken at the age of 5 months and 14 years, respectively. The first biopsy sample contained internally placed nuclei in 7% of the muscle fibers, abundant minute myotubes, and hypertrophic muscle fibers. The second biopsy sample showed internally placed nuclei in 40% of the muscle fibers, and hypotrophic fibers. We suggest that the histological findings in early-onset CNM are the result of a complex dynamic process, which includes a delay in maturation.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1432-0533
    Schlagwort(e): Key words Aging ; Blood-brain barrier ; Horseradish peroxidase ; Senescence-accelerated mouse ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The ultrastructural features of microvessels showing increased permeability to intravenously injected horseradish peroxidase (HRP) were examined in the olfactory bulbs of senescence-accelerated prone mice (SAMP8), which showed age-related deficits in learning and memory, and senescence-accelerated resistant mice (SAMR1), which did not show the age-related deficits. HRP was visualized with tetramethyl benzidine (TMB) and diaminobenzidine (DAB) for light and electron microscopic examination, respectively. In the olfactory bulbs of 13-month-old SAMP8 mice, the staining reaction with TMB for HRP appeared in the neuropil of central area (granule cell layer and subependymal layer), in the pia mater and in the vascular wall. Some vessels located in the central area showed several changes observed at the ultrastructural level. The cytoplasm of the endothelial cells, especially in the arterioles, was segmentally thickened and contained numerous vesicles and vacuoles, some of which were HRP positive. The endothelial cell surface was occasionally undulated with microvillous protrusions. Membranous inclusions within the basal lamina, suggesting the cellular (presumably pericytal) degeneration, were frequently observed, especially in venules. The collagen deposits were occasionally observed in the subendothelial space of some vessels. Perivascular cells with vacuolated inclusions or lipid-like droplets were present around some vessels in the central area of the olfactory bulbs of aged SAMP8 mice. On the other hand, in the microvessels located in the areas negative for HRP-TMB reaction, except the vessel walls, the cytoplasm of the endothelial cells with smooth luminal surface was flattened and some vesicles located there contained HRP-DAB reaction product. Weak staining reaction with TMB for HRP appeared also in the central area of the olfactory bulbs of 3-month-old SAMP8 mice and 3- and 13-month-old SAMR1 mice. The cytoplasm of the endothelial cells in the olfactory bulbs of these mice was focally thickened and contained some cytoplasmic vesicles. Occasionally, the endothelial cell surface was moderately undulated with few microvillous protrusions. Membranous inclusions within the basal lamina were not observed in these animals. These findings indicate that the endothelial cells and pericytes in some vessels located in the central area of the olfactory bulb of aged SAMP8 mice, which show staining reaction with TMB for HRP, are ultrastructurally changed, suggesting their altered functions.
    Materialart: Digitale Medien
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  • 11
    ISSN: 1432-069X
    Schlagwort(e): Key words Barrier function ; pH ; Stratum corneum ; Lamellar body ; Lipid content ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Epidermal permeability barrier homeostasis requires the postsecretory processing of polar lipid precursors into nonpolar lipid products within the stratum corneum (SC) interstices by a family of lipid hydrolases. A specific requirement for β-glucocerebrosidase (β-GlcCer’ase), which exhibits a distinct acidic pH optimum, is particularly well documented. Therefore, we sought to determine whether the recovery of the barrier after acute insults requires acidification of the SC. We examined permeability barrier recovery by assessing changes in transepidermal water loss (TEWL), SC membrane ultrastructure utilizing ruthenium tetroxide (RuO 4 ) postfixation, and β-GlcCer’ase activity by in situ zymography at an acidic vs neutral pH. Barrier recovery proceeded normally when acetone-treated skin was exposed to solutions buffered to an acidic pH. In contrast, the initiation of barrier recovery was slowed when treated skin was exposed to neutral or alkaline pH, regardless of buffer composition. In addition, enhancement of the alkaline buffer-induced delay in barrier recovery occurred with Ca 2+ and K + inclusion in the buffer. Moreover, the pH-dependent alteration in barrier recovery appeared to occur through a mechanism that was independent of Ca 2+ - or K + -controlled lamellar body secretion, since both the formation and secretion of lamellar bodies proceeded comparably at pH 5.5 and pH 7.4. In contrast, exposure to pH 7.4 (but not pH 5.5) resulted in both the persistence of immature, extracellular lamellar membrane structures, and a marked decrease in the in situ activity of β-GlcCer’ase. These results suggest first that an acidic extracellular pH is necessary for the initiation of barrier recovery, and second that the delay in barrier recovery is a consequence of inhibition of postsecretory lipid processing.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 206 (1998), S. 38-43 
    ISSN: 1431-4630
    Schlagwort(e): Key words Starch ; Gels ; Kamaboko ; Surimi ; Gelatinization ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract  The purpose of this work was to study the changes undergone by starch during heat-induced surimi gel preparation either with or without added egg white, and their effects on the structure of gels using light and scanning electron microscopy. Gels were made from SA-grade Alaska pollack (Theragra chalcogramma) surimi with: (1) salt (3%, w/w); (2) salt and waxy corn starch (3% and 5%, respectively w/w); or (3) salt, waxy corn starch and egg white (3%, 5% and 5%, respectively, w/w). Final moisture was adjusted to 73% or 83%. The gels were prepared by prior setting (40°C, 30 min, followed by 90°C, 30 min) or cooking (90°C, 30 min). The prepared gel was frozen and stored at –20°C (±1°C) until analysis. Samples were observed by light and scanning electron microscopy. The results show that the starch granules alter according to the processing conditions, with the predominance of crystalline or amorphous morphology depending upon the availability of heat and water. Large cavities formed in the protein gel matrix during setting can trap water; as a result, water availability is limited for starch to swell and gelatinize even in the high-moisture gel.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Der Pathologe 19 (1998), S. 373-378 
    ISSN: 1432-1963
    Schlagwort(e): Schlüsselwörter Metaplastische Brustdrüsenkarzinome ; Plattenepithelmetaplasie ; Plattenepithelkarzinom ; Immunhistologie ; Elektronenmikroskopie ; Zytophotometrie ; Key words Pure squamous cell carcinoma ; Mammary gland ; Squamous metaplasia ; Immunohistology ; Cytophotometry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Squamous metaplasia can be demonstrated in about 4% of all invasive carcinomas of the breast. Primary squamous cell carcinomas of the breast are rare, since they occur in less than 1% of all primary invasive breast carcinomas. In order to classify a breast tumor as a primary squamous cell carcinoma one must exclude an epidermal origin, especially from the nipple region and the possibility of metastatic infiltration of the breast by a squamous cell carcnoma from a different location. Causative and formal pathogenesis of primary squamous cell carcinoma of the breast is not clear. A pluripotent embryonal stem cell origin is discussed, considering the phylogenetic descent of the mammary gland from skin appendages. Squamous metaplasia is also suggested to be a precursor of squamous cell carcinoma. Here endocrine stimulation and chronic inflammation may both play an inductive role. The number of published cases of squamous cell carcinomas developing years and decades after implantation of silicon prostheses has increased in recent years. These tumors probably develop on top of squamous metaplasia induced by the inflammatory pseudocapsule. Estimating the prognosis and therapeutic management in patients with squamous cell carcinoma of the breast should follow the same guidelines as for other squamous cell cancers.
    Notizen: Zusammenfassung Plattenepithelmetaplasien werden bei etwa 4% aller invasiven Brustdrüsenkarzinome beschrieben. Reine Plattenepithelkarzinome der weiblichen Brustdrüse sind mit einem Anteil von wahrscheinlich unter 1% an allen invasiven epithelialen Tumoren der Mamma selten. Von einem primären Plattenepithelkarzinom der Brustdrüse darf nur gesprochen werden, wenn zum einen der Ursprung von der Epidermis, insbesondere auch im Bereich des Mamillentrichters ausgeschlossen ist und zum anderen keine metastatische Infiltration in die Brustdrüse durch ein Plattenepithelkarzinom anderer Organlokalisation vorliegt. Die kausale und formale Pathogenese der primären Plattenepithelkarzinome der Brustdrüse ist unklar. Zum einen wird ein Ursprung von pluripotenten embryonalen Stammzellen diskutiert, wobei bedacht wird, daß die Brustdrüse entwicklungsgeschichtlich ein Hautanhangsgebilde darstellt. Zum anderen werden Plattenepithelmetaplasien als Vorstufe der Plattenepithelkarzinome diskutiert, wobei neben einer endokrinen Induktion auch länger bestehende Entzündungsreize eine Rolle spielen sollen. In den letzten Jahren wird immer häufiger darüber berichtet, daß oft Jahrzehnte nach Implantation von Silikonprothesen periprothetische Plattenepithelkarzinome entstehen, die wahrscheinlich über die Stufe einer Plattenepithelmetaplasie der entzündlichen Prothesenpseudokapsel entstehen. Die Abschätzung der Prognose und therapeutische Maßnahmen bei primären Plattenepithelkarzinomen der Brustdrüse sollten an den Erfahrungen mit Plattenepithelkarzinomen anderer Organlokalisation ausgerichtet werden.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Sexual plant reproduction 11 (1998), S. 284-291 
    ISSN: 1432-2145
    Schlagwort(e): Key words Abies ; Egg cell ; Plastid inheritance ; RFLP ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  The ultrastructure of egg cells in Abies alba was examined to elucidate the lack of maternal inheritance of plastids. Before fertilization, maternal plastids are absent in the perinuclar zone containing mainly mitochondria and smooth endoplasmic reticulum. During egg cell development the maternal plastids are transformed into large inclusions which are situated mostly towards the periphery of the egg cell, and finally disintegrate. As a consequence, they do not participate in zygote formation. RFLP analysis of cpDNA of parental trees and their F1 interspecific hybrids (A. alba×A. numidica, A. alba×A. nordmanniana, A. nordmanniana×A. Alba) using HindIII and BamHI showed a paternal mode of cpDNA inheritance. Paternal inheritance has also been found with PCR/RFLP analysis of cpDNA from parental trees and their hybrids (A. alba×A. pinsapo, A. pinsapo×A. alba, A. pinsapo×A. numidica) using ApaI and HaeIII digests, as well as in the crosses of A. cephalonica×A. nordmanniana, A. nordmanniana×A. cephalonica, A. cephalonica×A. numidica using TagI digests.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Sexual plant reproduction 11 (1998), S. 121-130 
    ISSN: 1432-2145
    Schlagwort(e): Key words Egg cell ; Parthenogenesis ; Synergid ; Ultrastructure ; Wheat ; Zygote
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  The ultrastructure of the egg apparatus of the sexual (aestivum)-Salmon line (aS) and the isogenic but alloplasmic (kotschyi)-Salmon line (kS) of the Salmon system of wheat was studied by transmission electron microscopy 3 days before and during anthesis. Additionally, the zygotic stage of aS, 17 h after pollination, was included. Metabolic activity of egg cells from the sexual line aS was low 3 days before anthesis and increased dramatically after pollination and fertilization. This timing of increased activity was evident because of changes occurring in the egg cell nucleus and nucleolus, polysomes, endoplasmic reticulum and Golgi apparatus, and the completion of the cell wall around the zygote. In contrast to the sexual line, the egg cell of the parthenogenetic line showed high activity 3 days before anthesis. The metabolic and ultrastructural characters observed in the nucleus and cytoplasm of the kS line 3 days before and during anthesis corresponded with those of the isogenic sexual line aS during anthesis and 17 h after pollination, respectively. High metabolic activity observed in the persistent synergid of kS may be connected with the occurrence of additional embryos in seeds (twins) of this line.
    Materialart: Digitale Medien
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  • 16
    ISSN: 1432-072X
    Schlagwort(e): Key words Magnetic bacteria ; Biomineralization ; Magnetite ; 16S rRNA ; In situ hybridization ; Ultrastructure ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Natural enrichments of magnetic bacteria from the Itaipu lagoon near Rio de Janeiro were dominated by coccoid-to-ovoid morphotypes that produced unusually large magnetosomes. To determine the phylogenetic position of these unusual microorganisms, 16S rRNA genes were retrieved from bacteria magnetically separated from sediment of the Itaipu lagoon by in vitro amplification and cloning of PCR products into a plasmid vector. Partial sequencing of the obtained clones revealed two clusters of closely related sequences affiliated to a distinct lineage consisting exclusively of magnetic bacteria within the α-subclass of Proteobacteria. For a detailed phylogenetic analysis, several almost complete sequences of the 16S rRNA genes were determined. One representative clone of each cluster provided a PCR template for the in vitro transcription of group-specific polynucleotide probes complementary to a variable region of the 16S rRNA molecule. At least three different morphotypes of magnetic bacteria were reliably identified by post-embedding hybridization of ultra-thin sections. Electron microscopic analyses of hybridized cells enabled for the first time a detailed description of the morphological variety and ultrastructure of phylogenetically identified, uncultured magnetic bacteria. Two distinct coccoid bacteria were identified by the transcript probe complementary to the 16S rRNA sequence mabrj12, whereas the probe complementary to the sequence mabrj58 allowed the identification of an ovoid morphotype that displayed magnetosomes with the largest volumes observed to date.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 292 (1998), S. 275-282 
    ISSN: 1432-0878
    Schlagwort(e): Key words Interstitial cells (Cajal) ; Large intestine ; Fluorescent dyes ; Vital staining ; Ultrastructure ; Mouse (BALB/c)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  Interstitial cells of Cajal (ICCs) are believed to be a major element in generating the spontaneous rhythm of the gastrointestinal tract. A prominent problem in the study of these cells has been the difficulty in observing them in intact tissues. We used the lipophilic dye DiI to stain ICCs in the submucosal-circular muscle border of freshly dissected mouse colon. The placement of small DiI crystals in this area resulted in the labeling of ICC-like cells. Two main morphological cell types, viz., bipolar and multipolar, were noted. Bipolar cells had two primary processes emerging from the poles of an elongated soma. The mean length of these processes was 78.7 μm. These cells constituted 42.3% of the sample (n=105). Multipolar cells (54.3% of total) had a less elongated soma and extended 3–6 main processes whose mean length was 56.3 μm. These processes showed no preferred direction. The length of the primary processes of bipolar cells was 40% greater than that of multipolar cells (P〈0.02). Three cells (2.9%) had only one primary process. The DiI stain could be converted into a stable electron-opaque product. Electron-microscopic observations showed that these cells had the typical appearance of ICCs reported in previous studies. This staining method should be useful for physiological investigations of ICCs in gastrointestinal tissues.
    Materialart: Digitale Medien
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  • 18
    ISSN: 1432-0878
    Schlagwort(e): Key words Cutaneous scent glands ; Apocrine glands ; Myoepithelial cells ; Holocrine glands ; Ultrastructure ; Lectins ; Cytokeratins ; Impala ; Aepyceros melampus (Artiodactyla)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  The cutaneous glands of the forehead and the metatarsus were studied by histological and histochemical methods and electron microscopy in adult male and female impalas in various seasons of the year. All glandular areas consist of apocrine and holocrine glands, which, however, occur in different proportions. Our findings in the apocrine gland cells suggest (1) the synthesis and exocytosis of a glycoproteinaceous secretory product stored in secretory granules, (2) typical apocrine secretion of the transformed apical cytoplasm, and (3) transepithelial fluid transport. The Golgi apparatus and apical membrane have binding sites for several lectins (PNA, HPA, RCA I, WGA). Cytokeratins 7, 14 and 19 are expressed at various intracellular localizations, suggesting an active role in the secretory mechanisms. The glands of the male forehead show marked seasonal changes in activity that are correlated with the main phases of the reproductive cycle, with the highest cellular activity occurring during the rut in April/May. The female forehead glands are only moderately developed and do not undergo seasonal changes. The metatarsal glands are of equal size in males and females and show no seasonal changes in activity. This study supports the hypothesis that (1) forehead glands in the male have a signaling role in the rut and (2) the metatarsal glands have a more general, probably social role maintaining and restoring contact between herd members.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 293 (1998), S. 165-171 
    ISSN: 1432-0878
    Schlagwort(e): Key words Muscle injury ; Cytoskeleton ; Sarcomere organisation ; Immunohistochemistry ; Ultrastructure ; Rabbit (New Zealand White)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Immunohistochemical and electron-microscopic techniques were used to analyze the extensor digitorum longus muscles of New Zealand White rabbits 1 h, 1 day, 3, 7, and 28 days after repetitive eccentric contractions. Loss of the cytoskeletal protein desmin was the earliest manifestation of injury. Apart from 1 h post-exercise, all desmin-negative fibers stained positively with antibody to plasma fibronectin, indicating loss of cellular integrity accompanying cytoskeletal disruption. Fiber sizes were significantly increased from 1–7 days after exercise. The large (hyaline) fibers found in histological sections after repetitive eccentric contractions resulted from segmental hypercontraction of the fiber. This phenomenon occurred proximally and distally to plasma membrane lesions of the muscle fiber and necrosis and manifested itself as very short sarcomere lengths. Thus, in serial sections, staining characteristics, sizes and shapes of one and the same fiber often varied dramatically. We conclude that the following sequence of events occurs: cytoskeletal disruptions, loss of myofibrillar registry, i.e., Z-disk streaming and A-band disorganization, and loss of cell integrity as manifested by intracellular plasma fibronectin stain, hypercontracted regions, and invasion of cells. When a fiber is disrupted, the remaining intact fibers apparently take up the tension put on the muscle and later fewer fibers are subjected to eccentric contractions.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 294 (1998), S. 253-260 
    ISSN: 1432-0878
    Schlagwort(e): Key words P2X1 receptor ; Ultrastructure ; Cerebellum ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  The distribution of the P2X1 subtype of purinoceptors associated with the extracellular activities of ATP was studied in the rat cerebellum at the electron-microscope level. Receptors were labelled with peroxidase-antiperoxidase and the avidin-biotin-peroxidase complex for immunocytochemistry. Immunoreactivity to P2X1 receptors was localized in subpopulations of synapses between varicosities of parallel fibres of granule cells and dendritic spines of Purkinje cells. Unlabelled varicosities of parallel fibres formed asymmetric synapses with labelled dendritic spines, whereas labelled varicosities of parallel fibres formed asymmetric synapses with unlabelled dendritic spines. P2X1 immunoreactivity was also localized in some astrocyte processes. The functional significance of these findings is discussed.
    Materialart: Digitale Medien
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 294 (1998), S. 367-375 
    ISSN: 1432-0878
    Schlagwort(e): Key words Neurons ; Glia ; Tracheae ; Wing ; Ultrastructure ; Moth ; Manduca sp.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  This ultrastructural examination of sensory nerves of the Manduca wing has revealed that extensive remodeling occurs among insect sensory neurons and their associated glial cells between pupation and adult emergence. Systematic counts of axons in particular wing nerves throughout adult development have shown that a decrease in axon number per nerve occurs after day 6. The neurons and glial cells that die are believed to be cells present at pupation that have no apparent sensory function but that probably function as guidance scaffolding for neurons and glia that are born after pupation. Despite the loss of several axons from each wing nerve, these nerves continue to grow in diameter during the latter half of adult development as some of the surviving axons increase severalfold in diameter. Each growing wing nerve in turn apparently functions as a scaffold for the proximal to distal growth of adult tracheae. A correspondence exists between adult nerve pathways and adult tracheal pathways, with each trachea maintaining intimate contact with a wing nerve along its entire length.
    Materialart: Digitale Medien
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 291 (1998), S. 549-559 
    ISSN: 1432-0878
    Schlagwort(e): Key words Endolymphatic sac ; Ultrastructure ; Fluid transport ; Otoconia ; Newt ; Cynops pyrrhogaster (Urodela)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  The ultrastructure of the endolymphatic sac (ES) of the late stage larva of the Japanese red-bellied newt, Cynops pyrrhogaster (stage 57), was examined by light and transmission electron microscopy. The two endolymphatic sacs are located at the dorsal-medial side of the otic vesicle on the dorsal-lateral side of the midbrain in the cranial cavity. The wall of the sac is composed of a layer of cubical epithelial cells with loose, interposed intercellular spaces. The sac contains a large luminal cavity, in which endolymph and numerous otoconia are present. The epithelial cells of different portions of the sac have a similar structure. These cells contain an abundance of cytoplasmic organelles, including ribosomes, Golgi complexes, and numerous vesicles. Two types of vesicles are found in the epithelial cells: the “floccular” vesicle and the “granular” vesicle. The floccular vesicles are located in the supra- and lateral-nuclear cytoplasm and contain flocccular material. The granular vesicles have a fine granular substance and are usually situated apposed to the apical cell membrane. The granular vesicles are suggested to be secreted into the lumen, while the floccular vesicles are thought to be absorbed from the lumen and conveyed to the intercellular spaces by the epithelial cells. The apical surfaces of the epithelial cells bear numerous microvilli. Apparently floating cells, which bear long microvilli on the free surfaces, are observed in the lumen of the ES. Based on the fine structure, the function of the endolymphatic sac of the newt Cynops pyrrhogaster is discussed.
    Materialart: Digitale Medien
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 293 (1998), S. 253-269 
    ISSN: 1432-0878
    Schlagwort(e): Key words Septate junctions ; Ultrastructure ; Permeability ; Ions ; Epithelium ; Photoreceptor ; Hirudo medicinalis (Hirudinea)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  The leech photoreceptor forms a unicellular epithelium: every cell surrounds an extracellular “vacuole” that is connected to the remaining extracellular space via narrow clefts containing pleated septate junctions. We analyzed the complete structural layout of all septa within the junctional complex in elastic brightfield stereo electron micrographs of semithin serial sections from photoreceptors infiltrated with colloidal lanthanum. The septa form tortuous interseptal corridors that are spatially continuous, and open ended basally and apically. Individual septa seem to be impermeable to lanthanum; interseptal corridors form the only diffusional pathway for this ion. The junctions form no diffusion barrier for the electron-dense tracer Ba2+, but they hinder the diffusion of various hydrophilic fluorescent dyes as demonstrated by confocal laser scanning microscopy (CLSM) of live cells. Even those dyes that penetrate gap junctions do not diffuse beyond the septate junctions. The aqueous diffusion pathway within the septal corridors is, therefore, less permeable than the gap-junctional pore. Our morphological results combined with published electrophysiological data suggest that the septa themselves are not completely tight for small physiologically relevant ions. We also examined, by CLSM, whether the septate junctions create a permeability barrier for the lateral diffusion of fluorescent lipophilic dyes incorporated into the peripheral membrane domain. AFC16, claimed to remain in the outer membrane leaflet, does not diffuse beyond the junctional region, whereas DiIC16, claimed to flip-flop, does. Thus, pleated septate junctions, like vertebrate tight junctions, contribute to the maintenance of cell polarity.
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  • 24
    ISSN: 1432-0878
    Schlagwort(e): Key words Angiogenesis ; Capillary growth ; Prazosin ; Shear stress ; Skeletal muscle ; Ultrastructure ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  Chronic vasodilatation represents a stimulus for capillary growth associated with increased luminal shear stress. We have examined the ultrastructure of more than 2000 capillaries to establish whether the sequence of angiogenesis in response to this stimulus is similar to that described during development and under pathological circumstances. Administration of the α1-blocker prazosin to rats for 2 weeks led to a greater capillary length density in extensor hallucis proprius muscles without any change in capillary tortuosity: J v(c,f)=262±54 compared with 350±17 mm–2, control compared with prazosin (P〈0.002). There were obvious signs of endothelial cell (EC) activation after prazosin treatment, including an increased proportion of capillaries with rough endoplasmic reticulum, large cytoplasmic vacuoles, thickened endothelium and an irregular luminal surface. Capillaries from control muscles had a maximum of three ECs in cross section, whereas four ECs were noted in 0.8+0.5% of capillaries after 1 week (n.s.) and 2.5±0.9% after 2 weeks (P〈0.01) of treatment. This could be due to elongation and/or migration of ECs, as cell proliferation has not been described at these time points. There was also an increase in the proportion of capillaries having a narrow, slit-like lumen (1.7±0.8% of controls; 7.1±1.9% at 1 week; 8.8±2.5% at 2 weeks; P〈0.02), some of which were smaller in size (less than 2 μm diameter) than in controls (3–5 μm) and/or “seamless”, i.e. lacking EC junctions. These may represent newly formed vessels. Focal discontinuity of the basement membrane and abluminal EC processes were rarely seen, and capillary growth by abluminal sprouting appeared to be very infrequent (less than 0.001% of profiles). Of more importance was growth starting from the luminal side. Significantly more thin cytoplasmic processes were observed protruding into the lumen of capillaries after 1 week (47.5±6.2%, P〈0.001) and 2 weeks of prazosin (34.2±5.5%, P〈0.05) than in control vessels (16.7±3.9%). Some of these traversed the entire lumen and connected with endothelium of the opposite side, probably involving membrane fusion, resulting in the appearance of a double lumen. Individual capillaries with a complete double lumen were observed after 2 weeks’ prazosin but comparatively rarely, in only four out of six muscles. These findings indicate a pattern of luminal growth which is completely different from intussusceptive growth previously described during development, and from the abluminal capillary sprouting seen under pathological circumstances.
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Protoplasma 204 (1998), S. 155-169 
    ISSN: 1615-6102
    Schlagwort(e): Spores ; Ultrastructure ; Entorrhiza ; Microbotryum ; Tilletia ; Ustilago
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The concept and nomenclature for the elements of teliospore walls in smut fungi are presented and a survey of teliosporogenesis is given, as seen by light and transmission electron microscopy. Four developmental types are distinguished: the Ustilago, Microbotryum, Tilletia, and Entorrhiza type. In the Ustilago type, sporogenous hyphae are completely segmented into teliospore initials which are embedded in a hyaline matrix formed by gelatinised hyphal walls (found in species ofAnthracoidea, Cintractia, Heterotolyposporium, Kuntzeomyces, Macalpinomyces, Melanopsichium, Sporisorium, Testicularia, Tolyposporium junci, Trichocintractia, and species ofUstilago infecting members of the family Poaceae). In the Microbotryum type, septate sporogenous hyphae are also completely segmented into teliospore initials, however, they are not surrounded by a hyaline matrix (Microbotryum, Sphacelotheca, Ustilago spp. infecting dicotyledons). A yeast-like budding of teliosporogenic cells is observed for some species ofMicrobotryum, Sphacelotheca, andUstilago infecting dicotyledons. In the Tilletia type, teliospores differentiate locally in the sporogenous hyphae, in an apical or intercalary position, without a hyaline matrix (Conidiosporomyces, Doassinga, Entyloma, Erratomyces, Ingoldiomyces, Neovossia, Oberwinkleria, Rhamphospora, Tilletia). In all these types, the teliospore initials first develop a hyaline sheath under which the ornamentation, the exosporium, sometimes a middle layer, and the endosporium are successively deposited by the fungal cell. In the Entorrhiza type, the teliospores develop inside vital host cells with the wall of the sporogenous hypha included into the teliospore wall. The fungus develops a middle layer and an electron-transparent endosporium inside the hyphal wall while a layer forming the ornamentation is deposited onto the hyphal wall, probably by vesicles of dictyosomes of the host cell.
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  • 26
    ISSN: 1615-6102
    Schlagwort(e): Neck cell proliferation ; Binucleate ; Douglas fir ; Conifers ; Genetic instability ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary To study the effect of culturing on megagametophytes of Douglas fir (Pseudotsuga menziesii) and hybrid larch (Larix × eurolepis), cones were collected at the time of fertilization and the megagametophytes were removed, then placed on medium. We used a modified Murashige and Skoog medium supplemented with 5% lactose and 10% polyethylene glycol 4000. A variety of cell types proliferated including prothallial, neck, and jacket cells. Some of these multiplying cells showed a binucleate condition. The prothallial cells of the apex divided and expanded. The neck cells formed clusters composed of more cells than normally found in situ; though otherwise they showed ultrastructural similarity to neck cells in situ. These neck cells had large numbers of active Golgi complexes, numerous large and small vacuoles, coated vesicles, smooth vesicles, a well-developed endoplasmic reticulum, and thickened cell walls. These are the first reports of neck cell multiplication and induction of a binucleate state for gymnosperm megagametophyte cells in vitro.
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Protoplasma 201 (1998), S. 30-37 
    ISSN: 1615-6102
    Schlagwort(e): Cell-to-cell communication ; Plasmodesmata ; Ultrastructure ; Wounding ; 2-Deoxy-D-glucose
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The transport of ions and metabolites through plasmodesmata has been thought to be controlled at the neck region where the cytoplasmic annulus is constricted and where callose has also been localised. In order to determine the possible structural and functional effects of callose, its deposition was inhibited through incubation of the plant tissue with 2-deoxy-D-glucose (DDG) for 1 h prior to fixation in 2.5% glutaraldehyde. The inhibition of callose formation was monitored through aniline blue-induced fluorescence of callose. The neck region of the plasmodesmata fromAllium cepa L. roots treated with DDG exhibited a funnel-shaped configuration. This is in contrast to the plasmodesmata from tissue not incubated with DDG, which exhibited constricted necks similar to those previously reported. Both initial dissection and glutaraldehyde fixation induced neck constriction in plasmodesmata, however, dissection of tissue increased the frequency of constrictions. The inhibition of callose formation by chemical means showed that the neck constrictions and raised collars in this area are artefacts due to physical wounding and glutaraldehyde fixation. The external electron-dense material observed when tannic acid is included in the primary fixative appears to be unrelated to the deposition of callose at the neck region.
    Materialart: Digitale Medien
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Protoplasma 202 (1998), S. 23-37 
    ISSN: 1615-6102
    Schlagwort(e): Chloroplast development ; Cotton ; Fluorescence induction kinetics ; Ultrastructure ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Many of the studies of chloroplast ontogeny in higher plants have utilized suboptimal conditions of light and growth to assess development. In this study, we utilized structural, immunological, and physiological techniques to examine the development of the chloroplast in fieldgrown cotton (Gossypium hirsutum cv. “MD 51 ne”). Our youngest leaf sample developmentally was completely folded upon itself and about 0.5 cm in length; leaves of this same plastochron were followed for three weeks to the fully expanded leaf. The chloroplasts at the earliest stage monitored had almost all of the lamellae in small, relatively electron-opaque grana, with relatively few thylakoids which were not appressed on at least one surface. During the development of the thylakoids, the membranes increase in complexity, with considerable stroma lamellae development and an increase in the number of thylakoids per granum. Besides the increase in complexity, both the size and numbers of the chloroplast increase during the development of the leaf. Developmental changes in six thylakoid proteins, five stromal proteins, and one peroxisomal protein were monitored by quantitative immunocytochemistry. Even at the earliest stages of development, the plastids are equipped with the proteins required to carry out both light and dark reactions of photosynthesis. Several of the proteins follow three phases of accumulation: a relatively high density at early stages, a linear increase to keep step with chloroplast growth, and a final accumulation in the mature chloroplast. Photosystem-II(PS II)-related proteins are present at their highest densities early in development, with an accumulation of other parts of the photosynthetic apparatus at a latter stage. The early accumulation of PS-II-related proteins correlates with the much lower ratio of chlorophylla tob in the younger leaves and with the changes in fluorescence transients. These data indicate that some of the conclusions on chloroplast development based upon studies of intercalary meristems of monocots or the greening of etiolated plants may not be adequate to explain development of chloroplasts in leaves from apical meristems grown under natural conditions.
    Materialart: Digitale Medien
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Protoplasma 201 (1998), S. 101-109 
    ISSN: 1615-6102
    Schlagwort(e): Kinetochore ; Kinetoplastida ; Intranuclear microtubules ; Mitosis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The three-dimensional ultrastructural organization of the mitotic apparatus ofDimastigella mimosa was studied by computer-aided, serial-section reconstruction. The nuclear envelope remains intact during nuclear division. During mitosis, chromosomes do not condense, whereas intranuclear microtubules are found in close association with six pairs of kinetochores. No discrete microtubule-organizing centers, except kinetochore pairs, could be found within the nucleus. The intranuclear microtubules form six separate bundles oriented at different angles to each other. Each bundle contains up to 8 tightly packed microtubules which push the daughter kinetochores apart. At late anaphase only, midzones of these bundles align along an extended interzonal spindle within the narrow isthmus between segregating progeny nuclei. The nuclear division inD. mimosa can be described as closed intranuclear mitosis with acentric and separate microtubular bundles and weakly condensed chromosomes.
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 210 (1998), S. 25-39 
    ISSN: 1615-6110
    Schlagwort(e): Cyanophyta ; Cyanobacteria ; Cyanothece ; Synechococcus ; Cyanobium ; Ultrastructure ; nucleoids ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The fine structure of the type species of the genusCyanothece Komárek 1976,C. aeruginosa, is described and compared with the main cytological characteristics of morphologically related members of the generaCyanobium, Cyanobacterium andSynechococcus. Several morphological features, such as cell walls with thick outer layers containing a special type of vesicles, position of thylakoids, “keritomy” (net-like appearance of protoplast caused by arrangement of thylakoids, net-like nucleoids and/or by tendency to form intrathylakoidal spaces) and a special structure of mucilaginous envelopes were found to be characteristic of this genus, supporting its separate position among coccal cyanoprokaryotes (cyanobacteria, cyanophytes). The taxonomic significance of ultrastructural features in all mentioned genera is discussed.
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  • 31
    ISSN: 1615-6102
    Schlagwort(e): Spore balls ; Germ areas ; Ultrastructure ; Phylogeny
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Special features of teliospores in smut fungi are described, including teliospore connections, appendages, and germ pores. Balls of teliospores in species of many different genera cohere by remnants of hyphal walls, sheaths, and sometimes interlocking ornamentation. Teliospores are connected in pairs in species ofMycosyrinx andGeminago by special local structures. Appendages can be formed locally by persistent material from the sheath (Cintractia, Anthracoidea, Sphacelotheca), thickened parts of the spore wall (e.g.,Georgefischeria, Jamesdicksonia, Rhamphospora, Tolyposporella), or persistent walls of sporogenous hyphae (Rhamphospora, genera of the Tilletia relationship). Species ofGeorgefischeria, Jamesdicksonia, andTolyposporella have teliospore walls composed of more than three layers of different electron density. “Germ areas” corresponding to thinner parts of the spore wall are known, e.g., for species ofAnthracoidea, Cintractia, andUstilago infecting members of the family Poaceae, while distinct germ pores, one per teliospore, are found in some species ofThecaphora, “Tolyposporium”, andSporisorium. Teliospores ofMycosyrinx cissi have a germination ring. Characteristics of teliospores are used to discuss the phylogeny of smut fungi. A phylogenetic tree in accordance with teliospore characteristics is compared to those obtained from ultrastructural characteristics of host-parasite interaction, of septal pores, and from sequence data. Aspects of teliospore development help to define taxa at a high systematic level (Entorrhizales, Ustilaginales, Tilletiales/Entylomatales, Microbotryaceae), while details of ornamentation ontogeny delimit groups of genera (e.g., genera related toUstilago on members of the Poaceae andSporisorium, Cintractia andAnthracoidea, Tilletia) or single genera (e.g.,Melanopsichium, Dermatosorus, Mycosyrinx, Doassinga, Rhamphospora). Types of ornamentation (warty, reticulate), middle layers, teliospore balls, and germ pores evolved repeatedly by convergence. The smut teliospore itself probably evolved independently at least twice, or perhaps three (or more) times, in the Microbotryales, in the Entorrhizales, and in a common ancestor of the remainder of the Ustilaginomycetes.
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  • 32
    ISSN: 1615-6102
    Schlagwort(e): Spores ; Ultrastructure ; Microbotryum ; Tilletia ; Tolyposporium ; Ustilago
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The walls of mature teliospores and the development of ornamentation, as seen by transmission electron microscopy, are described for 37 genera of smut fungi, based on observations of ca. 120 species and on literature. Structural diversity of mature teliospore walls is due to differences in spore wall layers forming the spore wall (endosporium, middle layer, exosporium, ornamentation) and to different elements forming the ornamentation (exosporium, ornaments, sheath, hyphal wall, adjacent fungal cells, material of the host). During teliosporogenesis the outer layers are usually deposited first. At the beginning of the formation of the ornamentation the plasma membrane may be smooth or undulated carrying the developing ornaments on its tips or in its depressions. The ornamentation of some genera appears similar when seen by scanning electron microscopy, but can be the product of different developmental patterns (e.g., warts of species ofFarysia, Tilletia, andUstilago), however, warty and reticulate ornamentation can both be produced by similar developmental processes (shown, e.g., for species ofCintractia andTilletia). Typical structures of the mature teliospore wall and developmental patterns based on homologous similarities are described for the following groups of genera or species:Macalpinomyces, Melanopsichium, Sporisorium, andUstilago infecting members of the family Poaceae;Kuntzeomyces, Testicularia, andTrichocintractia; Anthracoidea, Cintractia, Heterotolyposporium piluliforme, andTolyposporium junci; Glomosporium, Sorosporium, andThecaphora; Conidiosporomyces, Erratomyces, Ingoldiomyces, Neovossia, Oberwinkleria, andTilletia; Entyloma, and genera of the Doassansia group;Liroa, Microbotryum, Sphacelotheca, Ustilago infecting dicotyledons, andZundeliomyces; Aurantiosporium, Fulvisporium, andUstilentyloma. Special characteristics of the teliospore wall were observed for the generaDermatosorus, Doassinga, Entorrhha, Farysia, Mycosyrinx, Rhamphospora, and some species ofTolyposporium.
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  • 33
    ISSN: 1860-1499
    Schlagwort(e): Solitary fibrous tumor of the pleura ; Mesenchymal cell ; Immunohistochemistry ; CD 34 ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A solitary fibrous tumor of the pleura (SFTP) in a 37-year-old woman was reported as a rare pleural tumor based on morphological, immunohistochemical, and electron microscopic studies. The results showed that the tumor was composed of spindle-shaped cells forming fascicular and interlacing patterns with a mixture of mature collagen. The tumor cells coexpressed vimentin and CD34 and lacked cytokeratin reactivity. Ultrastructurally, there were abundant collagenous fibrillae surrounding spindle-shaped cells in which the junctional complex, basement membrane-like structure, and microvilli were not seen. From literature review and observation of the morphological features around the tumor, we consider that the tumor originated from the stromal cells subjacent to the mesothelium.
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Medical molecular morphology 31 (1998), S. 151-155 
    ISSN: 1860-1499
    Schlagwort(e): Serous adenocarcinoma ; Peritoneal neoplasm ; Immunohistochemistry ; Ultrastructure ; Case report
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Two cases of serous surface carcinoma of the peritoneum (SSCP) are discussed. The first patient was a 48-year-old Japanese woman with abdominal pain and fullness. The second patient was a 66-year-old Japanese woman with abdominal fullness. In both patients, laparotomy revealed many tumor nodules on the peritoneal surface. However, the ovaries, the uterus, and other intraperitoneal organs were free from tumors. The serum levels of CA125 were excessively elevated. The tumor cells were arranged in a papillotubular pattern. Mitoses were frequent. Diastaseresistant PAS-positive, and hyaluronidase-resistant alcian blue-positive materials were observed. In immunohistochemistry, the tumor cells showed positive reactions for cytokeratin, EMA, CA125, and HBME-1, and, in contrast, negative reactions for CEA, thrombomodulin, vimentin, and HHF35. In analysis for Ber-EP4, all tumor cells of case 1 were negative, and a few tumor cells of case 2 were positive. Ultrastructurally, hobnail-shaped tumor cells rested on a continuous basal lamina. Each cell was attached to short desmosomes. Microvilli were slender, straight, and short, and some had core rootlets. Many primary lysosomes were aggregated in the basal portion of the cytoplasm. A few well-differentiated ciliated cells were present. These two cases were diagnosed as SSCP.
    Materialart: Digitale Medien
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  • 35
    ISSN: 1860-1499
    Schlagwort(e): Restitution ; Ultrastructure ; Cell migration ; Colon ; Saponin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The superficial colonic epithelia of rats were exposed to 1.0% saponin solution for 3 min and fixed at various periods thereafter. The repair or restitution process was observed by light as well as by transmission and scanning electron microscopy. The exposure of the luminal surface to saponin resulted in uniform and extensive damage to the superficial epithelial cells without affecting the cells in the crypts. At 3 min after saponin treatment, the damaged epithelial cells exfoliated from the mucosa and the basal lamina was exposed. Within 15 min, most of the exposed basal lamina was covered by squamous to low-cuboidal epithelial cells, probably migrating from the crypts. These epithelial cells extended large lamellipodia over the denuded basal lamina. After 15 min the damaged surface was completely covered with epithelial cells, which became columnar at 1 h. Tight junction protein ZO-1 became positive along the restituted epithelium. Proliferating-cell nuclear antigen (PCNA) staining showed that proliferation of epithelial cells occurred after the restitution. These results suggest that saponin treatment serves as a good model system to study colonic restitution, which is carried out by rapid migration from the remaining crypt cells, followed by cellular proliferation. Rapid formation of tight junctions spanning the damaged regions allows rapid restoration of the barrier function of the colonic epithelium.
    Materialart: Digitale Medien
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  • 36
    ISSN: 1860-1499
    Schlagwort(e): Pancreas ; Peripheral nerve ; Cancer ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Nerve invasion is one of the biological features of pancreatic cancer, and its mechanism remains to be determined. In this paper, we report on 37 pancreatic cancer specimens observed by immunohistochemical and electron microscopical techniques. The results showed that pancreatic cancer directly invaded and destroyed the perineurium. At the early stage of disease, the peripheral nerve and synaptic membrane were easily destroyed by cancer cells, and invasion and metastasis continuously advanced along the perineural space and central side of nerves. These results suggest that the soft tissue and nerve plexus on the dorsal region of the pancreas may contribute to the recurrence of pancreatic cancer after duodenopancreatectomy.
    Materialart: Digitale Medien
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Medical molecular morphology 31 (1998), S. 185-192 
    ISSN: 1860-1499
    Schlagwort(e): Rat fetal heart ; Capillary angiogenesis M ; Myocardial cleft ; Fibroblast ; Desmosome-like structure ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract To determine the course of capillary angiogenesis in the rat fetal heart, transmission electron microscopy was used to examine the development of both capillaries and cardiomyocytes. In the 15-day-old embryo, the coronary vessels had spread into the superficial space. In the 16-day-old embryo, the coronary vessels began to enter the myocardium. In the 17-day-old embryo, the terminal vascular bed had developed and a marked increase in the population of myocytes was evident. In capillaries entering the myocardium, the outgrowth of endothelial cells into the myocardial cleft was evident. These clefts were formed by intercalated disk and desmosome-like structures. The fibroblasts were always found close to the capillaries or in contact with endothelial cells during the fetal stage to the first neonatal week. In the interstition period, the fibroblasts were not found close to the capillaries. These results are discussed in relation to the role of myocardial clefts and the role of fibroblasts in fetal capillary angiogenesis.
    Materialart: Digitale Medien
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  • 38
    ISSN: 1860-1499
    Schlagwort(e): Malignant myoepithelioma ; Oral palate ; Immunohistochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Malignant myoepithelioma arising in the palatal gland is extremely rare. The present study demonstrated ultrastructural and immunohistochemical features of malignant myoepithelioma transformed from long-standing benign myoepithelioma occurring in the palatal gland. Microscopically, the tumor mass was composed of plasmacytoid cells and epitheloid cells. The malignant feature was seen only at the area adjacent to the bone. Immunohistochemically, most of the cells were S-100 positive, whereas vimentin and keratin were only partially positive. Glial fibrillary acid protein (GFAP) was positive at the peripheral cells of the solid nests and epitheloid cells with myxoid stroma. Ultrastructurally, filament-rich cells, tonofilament-rich cells, and filament-poor cells were observed. At the area adjacent to the bone, the cells implying malignancy were filament-poor cells in which the luminal structures could be detected. From these findings, a scarcity of filaments in myoepitheliomatous components may imply a malignancy.
    Materialart: Digitale Medien
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  • 39
    ISSN: 1432-0568
    Schlagwort(e): Testicular peritubular cells ; Boar ; Postnatal development ; Ultrastructure ; Contractility
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Membrana propria der Hodentubuli des Schweines zeigt einen deutlichen Schichtenbau: Auf die Basalmembran des Tubulusepithels (a) folgen eine nicht-celluläre Lage mit Kollagenfibrillen (b), die von einer inneren (c) und einer äußeren (e) Basalmembran umhüllten peritubulären Zellen (d) und dann das intertubuläre lockere Bindegewebe (f). Die ausdifferenzierten peritubulären Zellen haben viele morphologische Merkmale mit glatten Muskelzellen gemeinsam. So besitzen sie Plasmalemmeinbuchtungen in Form pinocytotischer Bläschen sowie eine große Anzahl von Filamenten mit einem Durchmesser von 60–70 Å, welche über elektronendichte Strukturen an der Innenseite des Plasmalemms befestigt sind. Ein Golgi-Apparat, rauhes endoplasmatisches Reticulum, Mitochondrien und Mikrotubuli bevorzugen eine kernnahe Position. Im Gegensatz zu den Verhältnissen bei anderen Species sind viele charakteristische Eigenschaften der peritubulären Zellen schon vor der Pubertät ausgebildet. Die Filamente können bereits am 4. Tag als feines Netzwerk beobachtet werden, sie erfahren am 25. Tag eine starke Vermehrung und sind von nun an regelmäßig orientiert. Auch andere Befunde sprechen dafür, daß die peritubulären Zellen um den 25. Tag eine gesteigerte Aktivität entfalten. Die histochemisch nachgewiesenen Konzentrationen von alkalischer Phosphatase, Adenosintriphosphatase und Glucose-6-phosphatase erreichen zu diesem Zeitpunkt die hohen Werte, die auch für die weitere Entwicklungsphase und die ausdifferenzierten peritubulären Zellen typisch sind. Pinocytotische Bläschen erscheinen in größerer Anzahl ab dem 97. Tag. Mit dem 140. Tag sind die peritubulären Zellen morphologisch ausdiffrenziert.
    Notizen: Summary The boundary tissue of the porcine testicular seminiferous tubule (membrana propria) exhibits a distinct stratification: the basement lamina of the tubular epithelium (a) is followed by a non-cellular layer with collagen fibrils (b), the peritubular cells (d) with an inner (c) and outer (e) basement lamina and finally the intertubular loose connective tissue (f). Fully developed peritubular cells have many morphological features in common with smooth muscle cells, for instance inpocketings of the plasmalemma (pinocytotic vesicles) and a great number of filaments measuring 60–70 Å in diameter. These filaments are fixed at the inner side of the plasmalemma by means of electron-dense structures. The Golgi apparatus, rough endoplasmic reticulum, mitochondria and microtubules prefer a juxtanuclear position. In contrast that is seen in other species the porcine peritubular cells develop many of their characteristic features before puberty. In samples of the 4th day a fine network of filaments is already visible within the cytoplasm. These filaments are strongly augmented at the 25th day, and from now on they are arranged in a regular fashion. Other findings, also, underline an increased activity of the peritubular cells around day 25. At that time the concentrations of histochemically demonstrated alkaline phosphatase, adenosine triphosphatase and glucose-6-phosphatase reach the high levels typical for the stages of further development and the fully differentiated cells. Pinocytotic vesicles appear in great numbers from day 97. At the 140th day the morphology of the porcine peritubular cell is completely developed.
    Materialart: Digitale Medien
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 139 (1973), S. 319-336 
    ISSN: 1432-0568
    Schlagwort(e): Fetal thyroid ; Microfilaments ; Lysosomes ; Acid phosphatase ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The mesobranchial area and the median thyroid anlage of embryonic albino mice were investigated from the somite stage 4 to 40 (81/2–10 days of gestation). In stage I (5–25 somites), there is an unequal growth and differentiation of the epithelium in the floor of the pharynx, whereby a mesobranchial area with a stratified or pseudostratified epithelium is formed. This area is distinct from the remaining pharyngeal epithelium, among other things by an apical microfilament system in the superficial epithelial cells. It is found just basal to a row of plump cytoplasmic protrusions, which extend into the lumen of the pharynx. In stage II (26–40 somites), the cranial part (median thyroid anlage) of the mesobranchial area thickens in relation to the caudal part and grows down into the underlying mesenchyme. The filament system is concentrated in the superficial cell layer of the median thyroid anlage at the beginning of stage II and disappears during downgrowth. In both stages, but most pronounced in stage II, there is a population of 0.1–5 μ intracellular bodies, which occasionally contain the remains of organelles. The larger bodies, which often contain the remains of nuclei, are usually found peripherally while the smaller ones are more evenly distributed. Acid phosphatase can often be demonstrated histochemically in small bodies, while larger bodies are usually without reaction. Cells with pycnotic nuclei and/or degenerated cytoplasmic components are regularly found. Acid phosphatase can also be demonstrated in Golgi complexes and surrounding vesicles. Basal to the epithelium, bodies are occasionally found which may possibly have been extruded from that tissue.
    Materialart: Digitale Medien
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 141 (1973), S. 161-169 
    ISSN: 1432-0568
    Schlagwort(e): Rat ; Uterus ; Stroma ; Ultrastructure ; Sex steroids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The effect of progesterone and oestrogen on the central uterine stroma has been examined in order to analyze what changes occur when the uterus is hormonally prepared for implantation. Both progesterone and oestrogen, when given separately, cause nucleolar enlargement and growth of the granular endoplasmic reticulum. However, after progesterone treatment the nuclei are large and spherical whereas they are spindle-shaped after oestrogen treatment. When oestrogen is administered to the progesterone-treated rat little change occurs in the stromal morphology. There is little morphological support to the view that oestrogen acts on the stroma to increase endometrial sensitivity. Further, progesterone seems to stimulate the synthesis of RNA and of cellular protein only in the stromal cell while oestrogen has a similar effect in all cell types of the uterus.
    Materialart: Digitale Medien
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 143 (1973), S. 95-114 
    ISSN: 1432-0568
    Schlagwort(e): Cleavage stages ; Blastocyst ; Pig ; Nucleus ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Ultrastructural observations of morphological changes in nuclei and cytoplasm of pig embryos during cleavage and early blastocyst stages are presented. Compact nuclear bodies (nucleosphaeridies) are demonstrable in the cleavage stages, and occasionally in the inner cell mass of blastocysts. The transformation of nucleosphaeridies leading to the formation of a peripheral network are usually found at the eight-cell stage. In morula, nucleoli make their first appearance as clearly distinguishable morphological entities. A marked disorganization of nuclear envelope is observed near to the cytoplasmic annulate lamellae (CAL) indicating a possible process of transformation of the former to the latter. During premorula stages cytoplasmic organelles (Golgi complex, endoplasmic reticulum, and CAL) are predominantly concentrated around the nucleus. CAL associated with fibrillogranular material similar to the material of the nucleoplasm occur in juxtanuclear positions. In the two-cell stage, degenerating paternal mitochondria are observed. In the morula the number of spherical mitochondria fell while that of elongated mitochondria increase. The trophoblast cells of the blastocyst stage contain cytoplasmic microfilaments which are closely associated with cell organelles, particularly the desmonsomes. Structurally changed mitochondria near the yolk globules and inclusion bodies of various morphology are found. A basal lamina is discernible parallel to the trophoblast layer facing the blastocoel. The observations are discussed in relation to physiological phenomena known to occur during embryogenesis.
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 25 (1973), S. 27-35 
    ISSN: 1432-0533
    Schlagwort(e): Ultrastructure ; Chordoma ; Sacrococcygeal
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructure of a sacrococcygeal chordoma is presented. The cells vary in their size and electron density but are thought to have a common origin. The nuclei presented prominent nucleoli and intranuclear bodies. Centrioles were seen in some of the cells. The rough endoplasmic reticulum was prominent and in most cells was very distended and corresponded to the intracellular vacuoles of light microscopy. The contents of the rough endoplasmic reticulum and the abundant extracellular substance were similar.
    Materialart: Digitale Medien
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 26 (1973), S. 285-299 
    ISSN: 1432-0533
    Schlagwort(e): Herpes simplex Virus ; Ultrastructure ; Viral Infection ; Virus-Host Interaction ; Nervous System
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The nervous system and small intestine of mice infected with herpes simplex virus were examined by electron microscopy from the viewpoint of virus-host interaction. The host cells examined included the neuron, astrocyte, oligodendrocyte, and Schwann cell. The susceptibility of the latter was not less than that of the neuron. The endothelial cell, perineural fibrocyte and smooth muscle cell were also host cells. Replication of herpes virus in the nervous system was proven to be identical to that occurringin vitro; initial reproduction of nucleocapsids in the nucleus and subsequent maturation at the nuclear membrane with envelope formation, followed by discharge into the cytoplasmic reticular cavities and finally release from the host cell. Inconsistency in the distribution of virus particles and viral antigen was chiefly concerned with the host cell nucleus and the glial cytoplasm. Herpes virions, though few, were identified in the axons of peripheral nerves, and in the periaxonal space of myelinated fibres in the brain and the nerve ganglia. Virions were present in tiny vesicles in the perikarya or as naked particles. In the distal parts of peripheral nerve, there was marked dissociation in the amount of virions between Schwann cells and the axon. The significance of the endoneural space and the axon in the neural speread of infection is discussed briefly.
    Materialart: Digitale Medien
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 24 (1973), S. 331-339 
    ISSN: 1432-0533
    Schlagwort(e): Diabetic Amyotrophy ; Muscle Biopsy ; Ultrastructure ; Type II Fibre Atrophy ; Partial Denervation ; Neurogenic Atrophy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Seven cases of diabetic amyotrophy were investigated by histochemistry and electron microscopy of biopsied muscles. Type II fibre atrophy of various grades was observed in the proximal atrophic muscles. Various changes of Z-band were observed in type II atrophic muscle fibres. In addition, mitochondrial changes, accumulation of glycogen, thickening of the capillary basement membrane and changes in the intramuscular nerves were also observed, both in the proximal and distal muscles. Some impaired motoneuron innervation of proximal muscles as well as distal muscles in a poorly controlled diabetic condition is suspected in “diabetic amyotrophy”.
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 13 (1973), S. 83-92 
    ISSN: 1432-0827
    Schlagwort(e): Proteoglycan ; Collagen ; Cartilage ; Electron Microscopy ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé L'élimination de protéoglycans solubles de coupes de cartilage costal de boeuf, par extraction dans une solution de 4M d'hydrochlorure de guanidinium, permet de mettre en évidence des quantités abondantes de collagène dispersé et désagrégé dans la matrice. Les protéoglycanes, résistants à l'extraction, sont visibles sous forme de granules concentrés dans les régions périlacunaires. Les granulations plus importants des protéoglycanes semblent venir du chondrocyte. Dans la matrice, éloignée des chondrocytes, ces granules deviennent plus étroites. Un composant non granulaire “amorphe” masque les fibres de collagène, de telle sorte qu'elles sont difficilement visibles dans le cartilage intact.
    Kurzfassung: Zusammenfassung Die löslichen Proteoglycane wurden mittels Extraktion in 4 M Guanidinhydrochlorid aus Rippenknorpelschnitten des Rindes entfernt. Dies erlaubte die Sichtbarmachung von großen Mengen von verstreuten und auseinandergerissenen Collagen in der Matrix. Die Protoglycane, welche sich nicht extrahieren lassen, erscheinen als kleine, in den perilacunären Regionen konzentrierte Körnchen. Die großen Proteoglycan-Körner scheinen in den Chondrocyten zu entstehen. Sobald sie sich in die Matrix, außerhalb der Chondrocyten, verlagern, werden die Körner kleiner. Ein nicht-granulärer, „amorpher” Bestandteil verhüllt die Collagenfasern, so daß diese im intakten Knorpel nicht deutlich gesehen werden können.
    Notizen: Abstract Removal of the soluble proteoglycans from slices of bovine costal cartilage by extraction in 4 M guanidinium hydrochloride permitted the visualization of abundant amounts of dispersed and disaggregated collagen in the matrix. Proteoglycans which are resistant to extraction are seen as small granules which are concentrated in the perilacunar regions. Large proteoglycan granules appear to originate in the chondrocyte. As they come to occupy positions in the matrix distant from the chondrocyte, the granules become smaller. A non-granular, “amorphous” component masks the collagen fibers so that they cannot be readily seen in the intact cartilage.
    Materialart: Digitale Medien
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  • 47
    ISSN: 1432-1106
    Schlagwort(e): Ultrastructure ; Synapses ; Brain cortex ; Phospholipase A ; Membranes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The effect of purified Naja nigricollis phospholipase A on slices from motor cortex from rat brain was analysed at an ultrastructural level. Samples stabilized directly with glutaraldehyde were compared with samples incubated in buffer with or without enzyme. Plasma membranes of nerve terminals, synaptic contact regions and synaptic vesicles were the main parameters studied. As judged by the electron microscopic technique the synaptic areas show a high resistance to the enzyme treatment. The intercellular space of the synaptic cleft seems unaltered. At the highest concentrations of the enzyme an increased density is noticed at the presynaptic part of the membrane. The extracellular space widens and nerve terminals and mitochondria become distended with increasing enzyme concentrations. The membranes all through the tissue appear ruptured to small pieces and at the highest enzyme concentrations used, altered in their structural organization. Quantitative analysis shows that the number of synaptic vesicles per unit surface area decreases, while ruptures of the plasma membranes of nerve terminals increase in number with increasing enzyme concentrations.
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  • 48
    ISSN: 1432-0878
    Schlagwort(e): Heart ; Rabbit ; Sinuatrial node ; Sinuatrial ring bundle ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The cells of the sinuatrial ring bundle are smaller than the ordinary myocardial cells; they have a regular outline and a large content of myofibrils exhibiting distinct H-bands and M-lines. Rudimentary T-tubules are found. The cells are connected by frequent nexus junctions, desmosomes and regions of interfibrillar contact, both on the well developed intercalated discs and at the periphery of the cells. The cells in the cauda of the sinus node, which extends alongside the crista terminalis together with the right branch of the sinuatrial ring bundle, are irregularly outlined and have a highly variable diameter (1–10 μm). They occur in clusters of closely packed cells. The content of myofibrils is sparse and the fibrils exhibit no M-lines and only weak H-bands. No T-tubules are found. The cells are not connected by intercalated discs and no nexus junctions are found. Both tissues contain unmyelinated nerves and nerve fibres. Varicosities with mitochondria and vesicles are found in close apposition to the muscle cells.
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 136 (1973), S. 461-477 
    ISSN: 1432-0878
    Schlagwort(e): Neurohypophysis ; Acipenseridae ; Neurosecretion ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The neurohypophysis of sexually mature male and female Acipenser güldenstädti Brandt and Acipenser stellatus Pallas was studied light and electron microscopically. The recessus hypophysei lined with ependymal cells of two main types, “narrow” and “wide”, are in the center of the neurohypophysial “roots”. Processes from both cell types run radially to the basement membrane of the connective tissue layers abutting on the hypophysial intermediate lobe. Protrusions penetrating deep into the recessus hypophyseus are found in the apical parts of the “wide” cells. Pituicytes are rare in the neurohypophysis. The ultrastructure of both ependymal cell types and of the pituicytes is described. Nonmyelinated “Gomori-positive” (peptidergic) neurosecretory A1 and A2 type fibres and their terminals containing elementary neurosecretory granules (1400–1800 Å and 1000–1400 Å respectively) are the main structural elements of the neurohypophysis. Some “dark” and single myelinated neurosecretory fibres have been found. The adrenergic fibres (type B) were described earlier (Polenov et al., 1972a). The structural peculiarities of the neurohypophysis are discussed in functional and comparative-morphological terms.
    Materialart: Digitale Medien
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 139 (1973), S. 567-582 
    ISSN: 1432-0878
    Schlagwort(e): Compound Eye ; Apis mellifica ; Polarized light ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 1. Die Ausrichtung der Rhabdome ist in der Bienenretina nicht konstant. 2. Die Anordnung der exzentrischen Zellen in der Bienenretina ist ebenfalls nicht konstant, und es läßt sich keine symmetrische Verteilung dieser Zellen nachweisen. 3. Die Morphologie der Retina wird im Hinblick auf die Orientierung der Honigbiene nach dem Polarisationsmuster des vom blauen Himmel reflektierten Lichtes diskutiert.
    Notizen: Summary 1. The orientation of the rhabdoms shows no regularity within the retina of the honeybee. 2. The arrangement of the eccentric cells is also irregular within the retina of the honeybee. 3. The morphology of the retina is discussed regarding the ability of the honeybees to orient according to the pattern of the polarization of light reflected from the blue sky.
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 137 (1973), S. 471-480 
    ISSN: 1432-0878
    Schlagwort(e): Touch receptors ; Sense organs ; Monogenean ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ventral surface of the posterior sucker of Entobdella soleae, a monogenean skin parasite of the sole Solea solea, is covered with more than 800 papillae ranging in size from 2.5–19 μm in diameter. The papillae are penetrated by nerves which double over themselves to form a stack-like array of lamellae running parallel to the surface of the haptor. No cilia or associated structures are present within these presumed sense organs and the papillae have no opening to the exterior. The much larger sucker papillae of a related species, E. hippoglossi, have been shown to have a similar ultrastructure. The possibility that the papillae may be contact receptors or strain receptors, providing proprioceptive information assisting the coordination of the attachment organ, is discussed and the papillae are compared with vertebrate touch receptors.
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 138 (1973), S. 41-62 
    ISSN: 1432-0878
    Schlagwort(e): Germ cells ; Xenopus ; Spermatogenesis ; Chromatoid body ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The development of the male germ line in Xenopus laevis has been examined by electron microscopy. Findings have been compared to the parallel process in the female. Three structures unique to the germ line were found in both male and female cells: a fibrillar nuclear region free of DNA; largely proteinaceous masses of nuage material; and a chromatoid body. “Germ plasm” bodies of the egg and early embryo appear to represent a form of nuage material. The finding of a structure which can be identified as a chromatoid body in the female germ line is unique, as is its presence in sexually undifferentiated primordial germ cells. The chromatoid body in Xenopus, unlike that in mammals, does not persist in the spermatozoon. Instead, it dissociates into a series of coated vesicles during spermatogenesis. The chromosomal ultrastructure of meiotic prophase stages in Xenopus is similar in both sexes until diplotene, when male bivalents condense and enter meiotic metaphase instead of entering the extended lampbrush stage characteristic of the female. The multiple nucleoli present in gonia are lost at the onset of meiotic prophase, but no obvious mechanism for this process was observed.
    Materialart: Digitale Medien
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 141 (1973), S. 319-330 
    ISSN: 1432-0878
    Schlagwort(e): Gonadal wall ; Holothuroidea (Leptosynapta clarki) ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The holothurian testes (as well as ovary) consists of three layers arranged concentrically around a central lumen which contains developing germ cells. The outer coelomic layer measuring 6 μ in thickness contains ciliated squamous epithelial cells, smooth muscle processes, nerve tracts, and occasional pigment cells. Interior to the outer layer is a haemal sinus measuring about 3 μ and consisting of haemal fluid composed of collagenous fibers and electron dense particles. Coelomocytes are embedded in this extracellular fluid matrix. The inner germinal layer, measuring 9 μ at the thickest regions consists of germinal cells, squamous epithelial cells, and coelomocytes. Occasional coelomocytes within the haemal sinus and germinal layer of the testicular wall contain spermatids enclosed within cytoplasmic vacuoles, suggesting phagocytosis as one of their cellular functions.
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 141 (1973), S. 331-345 
    ISSN: 1432-0878
    Schlagwort(e): Sympathetic ganglion ; Granule-containing cells ; Synapses ; Three-dimensional analysis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The surface of 4 granule-containing cells, in a cluster within the rat superior cervical ganglion, was studied by a serial sampling technique for electron microscopy. The result shows that all the 4 cells receive one, or three afferent synaptic boutons from the preganglionic fibers impinging upon their somata, and a somatic efferent synapse exists at two locations on each soma of the 2 of these cells. The postsynaptic element of the efferent synapse is observed to be represented by non-vesiculated and vesiculated segments of dendrites, soma and a possible axon collateral of the adrenergic principal neuron of the ganglion. There is a remarkably constant development of the attachment plaque between the granule-containing cells themselves, representing 1.7–2.3% of surface area for each cell. The surface area exposed to the extracellular space (covered only by a basal lamina) varies from 0.1 to 2.3% of the total perikaryal surface of the 4 cells. A tendency is noted that those cells without efferent synapses possess a more extensive area exposed to extracellular space than those forming somatic efferent synapse to the postganglionic elements.
    Materialart: Digitale Medien
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 141 (1973), S. 469-478 
    ISSN: 1432-0878
    Schlagwort(e): Microsporida ; Nosema apis ; Developing spore ; Freeze-etching ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The mature spore possesses a thick spore coat and a particle-bearing spore membrane. The highly laminated polaroplast membranes are located at the anterior pole of the spore. Close to its base, the polar filament is surrounded by the polaroplast membrane. The polar filament runs spirally towards the posterior pole of the spore. A large portion of the polar filament is arranged in two layers. A similar arrangement was also observed in immature spores and in the sporoblast stage, although it was not so orderly arranged in the latter. The developing polaroplast membrane was observed in the immature spore, but not in the sporoblast. The sporoblast wall is much thinner than the spore coat, but has the same texture. Endoplasmic reticulum is the most prominent cytoplasmic organelle in the developing stages of Nosema apis. Porous nuclear envelopes are also observed in developing stages. The role of the endoplasmic reticulum in the formation of the polar filament, polaroplast and spore coat, and the function of the spore membrane, are discussed.
    Materialart: Digitale Medien
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 142 (1973), S. 89-102 
    ISSN: 1432-0878
    Schlagwort(e): Photoreceptors ; Larva ; Hemichordate ; Ultrastructure ; Evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The eyespots of tornariae of enteropneusts (Ptychodera flava from Hawaiian waters and an unknown species from southern California) were studied by electron microscopy. An ocellus is composed of two types of cells: sensory and supportive. The former is characterized by a bulbous cilium (with 9+2 axoneme) at its distal end, one or sometimes two arrays of microvilli from its sides below the cilium, and a basal axon. The latter features large, clear vesicles which presumably contained the reddish-orange pigment seen in the ocellus of a living larva. Five-day old tornariae of P. flava are positively phototactic. Both cilium and microvilli may function as photoreceptors. The tornarian ocellus studied is compared with eyespots of other invertebrates, and the evolutionary significance of its putative photoreceptors is discussed.
    Materialart: Digitale Medien
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 143 (1973), S. 107-116 
    ISSN: 1432-0878
    Schlagwort(e): Neurohypophysis ; Rat ; Pituicytes ; Organotypic culture ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Neural lobes of adult rats have been explanted and organ-cultured for 5–10 days. While perivascular cells and neurosecretory fibers undergo a progressive degeneration, scattered pituicyte-like cells are observed mostly associated with each other in number of two or three cells for group. Cultured pituicytes are quite similar to in vivo pituicytes except for some particular features as the shape of the nucleus and the number of dense bodies. Furthermore they share with the in vivo pituicytes the phagocytic capacity which appears even increased as far as neurosecretory fibers are concerned. Finally, degenerating pituicytes and free lipid droplets are observed in the intercellular spaces: the significance of these facts is discussed and tentatively interpreted. The organotypic culture of the neural lobe seems to represent an experimental model useful to obtain a relatively pure population of pituicytes.
    Materialart: Digitale Medien
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 143 (1973), S. 117-133 
    ISSN: 1432-0878
    Schlagwort(e): Nervous system ; Ctenophores ; Intra-mesogleal nervous system ; Synapses ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Ultrastructural evidence is given of the occurrence of nervous elements in the mesoglea of Ctenophores based on the presence of the typical synapses of this phylum. In Beroids, nervous fibers from the ectodermal nerve-net cross the epithelial basal membrane and run through the mesoglea; they are devoid of any ensheathing cell. These neurites build highly differentiated synapses upon the muscles and upon peculiar cells, tentatively named mesenchymal cells. In Cydippids, nerve fibers and nerve cell-bodies have been observed in the mesoglea of the tentacles. The mesogleal core of each tentacle contains mesenchymal cells and a thick strand of neurons and neurites, forming a kind of elongated ganglion. Neurites of either the axial neurones or the epithelial nerve-net neurones form numerous radial nerve strands across the tentacular muscles. Interneural, neuro-muscular and neuro-mesenchymal junctions are very frequent in the tentacle. As far as the organization of the mesoglea is concerned, the Ctenophora thus appear closer to Turbellaria than to Cnidaria.
    Materialart: Digitale Medien
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 143 (1973), S. 387-407 
    ISSN: 1432-0878
    Schlagwort(e): Oogenesis ; Urodela ; Yolk-formation ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Oogenesis was studied in adult Triturus vulgaris (Urodela) with the electron microscope. The oocytes investigated ranged between 50 μm and 1600 μm in diameter. Two types of yolk platelet formation were found. Since both types involve the incorporation of high numbers of pinocytotic vesicles they are believed to be of an extraoocytic origin. On the basis of the order of their appearance they were named primary and secondary yolk. Five different types of vesicles were found, which participate in a variety of activities, such as yolk formation and the formation of the Golgi apparatus. They originate from four different sources, namely the nuclear membrane, the cytoplasm in connection with ribosome-like particles, the Golgi apparatus and the plasma membrane through pinocytosis. The results obtained were discussed especially with respect to differences found between the anura and the urodela, such as the presence or absence of cortical granules or equivalent structures.
    Materialart: Digitale Medien
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  • 60
    ISSN: 1432-0878
    Schlagwort(e): Neurohypophysis ; Membranes ; Exocytosis ; Ultrastructure ; Freeze-fracturing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Posterior pituitary glands from normal rats, and rats which had been deprived of water for varying periods, were examined by the freeze-fracture method. This technique reveals large areas of the nerve cell membrane. Images consistent with exocytosis as the mechanism of release of the neurohypophysial hormones were observed. These modifications were most numerous after the rat had been starved of water for 2 days. In normal rats, the large number of neurosecretory granules within the nerve fibres caused a bulging of the nerve cell membrane. The “bulges” disappeared 2 days after removal of drinking water. Regions of the membrane displaying “bulges” were characterised by the absence of the typical membrane-associated particles. It is postulated that the close proximity of the neurosecretory granules to the nerve cell membrane may result in rapid fusion of the neurosecretory granules on stimulation of the gland. The change in properties of the nerve cell membrane overlying the neurosecretory granules, as suggested by the loss of membrane-associated particles, may represent a change in the structure of the membrane to a form which is more favourable for fusion.
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 145 (1973), S. 213-227 
    ISSN: 1432-0878
    Schlagwort(e): Sensory pore ; Crustacea ; Natantia ; Chemoreceptor ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé L'observation ultrastructurale du pore sensoriel de plusieurs espèces de Natantia révèle un complexe double. Un premier organe, le pore sensoriel principal, comprend une assise de cellules de soutien encadrant les parties distales de corps de cellules sensorielles. Ces cellules sensorielles portent des segments externes ciliaires qui se divisent dans une cavité sous-cuticulaire aplatie. En regard, la cuticule est amincie et comporte des micropores en forme de cratère et disposés par paires. A côté du pore sensoriel principal, un deuxième organe, le pore sensoriel latéral, est de taille plus réduite et est plus difficile à observer. Sous une invagination digitée de l'épicuticule, existe une cavité de forme complexe où s'épanouissent les segments externes ciliaires d'un faisceau de cellules sensorielles. Le pore sensoriel principal et le pore sensoriel latéral ont une ultrastructure de chémorécepteur.
    Notizen: Summary Ultrastructural observation of the sensory pore of several species of Natantia reveals a twofold organ. A main sensory pore (M.S.P.) comprises a layer of supporting cells which encapsulate the terminal region of sensory cell bodies. These sensory cells include two ciliary processes dividing into a flat sub-cuticular cavity. The cuticle opposite is thin and perforated with crater-like paired micropores. Next to the main sensory pore, a second organ, the lateral sensory pore (L.S.P.), is smaller and more difficult to observe. A complex-shaped cavity underlies a contorted epicuticular invagination. Ciliary outer segments, belonging to a bundle of sensory cells, branch out in this cavity. M.S.P. and L.S.P. appear to be chemoreceptors.
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  • 62
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 144 (1973), S. 435-452 
    ISSN: 1432-0878
    Schlagwort(e): Muscle spindles ; Intrafusal fibre types ; Development ; Deefferentation ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Muscle spindles of limb muscles were deefferented in neonatal rats by sectioning ventral roots or by removal of the lumbosacral spinal cord. Ten to 56 days after the operation, muscle spindles were examined in the medial gastrocnemius, extensor digitorum longus and soleus muscles. The differentiation of muscle spindles was not affected by deefferentation. The number of spindles in the investigated muscles was not reduced. Intrafusal fibres increased in number from two at birth to four per spindle on the average, as in normal muscles. The characteristic ultrastructural distinctions of nuclear bag and nuclear chain fibres developed as under normal conditions. However, intrafusal fibres atrophied slowly after fusimotor denervation, their polar zones becoming reduced in diameter by about 25% in comparison with control fibre diameters. Spindle capsules, on the other hand, increased in size and attained diameters comparable with normal spindles, appearing even somewhat distended. As intrafusal fibres degenerate after complete denervation at birth (Zelená, 1957), but differentiate in the absence of fusimotor innervation, it can be concluded that sensory nerve terminals induce and support their development. It is assumed that the morphogenetic influence of sensory terminals is mediated by release and uptake of a trophic substance at the synaptic junction. The occurrence of light and dense core vesicles in the sensory terminals and of coated invaginations and vesicles at both the axonal and plasma membrane speak in favour of such a possibility.
    Materialart: Digitale Medien
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  • 63
    ISSN: 1432-0878
    Schlagwort(e): Leydig cells ; Pekin Duck ; Testosterone ; Seasonal cycle ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé L'ultrastructure des cellules de Leydig et des cellules de Sertoli du testicule du Canard Pékin a été étudiée au cours de la phase printanière du cycle sexuel, soit de janvier à juillet. Parallèlement on a effectué chez les mêemes animaux la recherche histochimique de la Δ5-3 β-hydroxystéroïdedeshydrogénase (Δ5-3 β-HSDH) ainsi que le dosage, par chromatographie en phase gazeuse des stéroïdes androgènes dans le plasma veineux périphérique et dans le testicule. Les cellules de Leydig du Canard possèdent les organites cytoplasmiques spécifiques des cellules stéroïdogènes (reticulum lisse, mitochondries à crêtes tubulaires) ainsi que d'autres structures souvent rencontrées dans ce type cellulaire (microfilaments, vacuoles, granules denses). Les cellules de Sertoli contiennent un reticulum agranulaire moins développé que celui des cellules de Leydig et, très rarement, des mitochondries à crêtes tubulaires. Ces divers organites cytoplasmiques subissent un cycle saisonnier. La différenciation du reticulum lisse et des crêtes mitochondriales tubulaires commence en janvier et atteint son optimum en mars. Leur régression s'amorce en avril; d'abord accompagnée de structures dégénératives transitoires; elle conduit à la dispartion totale de ces organites en mait. Aucun indice de nécrose n'est observé dans ces cellules. Histochimiquement, une activité Δ5-3 β-HSDH est présente dans les cellules de Leydig et, à un degré moindre, dans les tubes séminifères. Son intensité varie au cours du cycle. La confrontation de l'étude morphologique avec les résultats des dosages hormonaux montre qu'il existe une bonne corrélation entre le développement puis la régression du reticulum lisse et des crêtes tubulaires des mitochondries ainsi que des critères histochimiques de la Δ5-3 β-HSDH d'une part et l'évolution de la testostérone plasmatique et testiculaire d'autre part. De plus on observe une augmentation du rapport testostérone/Δ4-androstènedione testiculaire parallèlement au développement des organites cytoplasmiques. Ces organites semblent donc bien impliqués dans la synthèse et la sécrétion de la testostérone chez le Canard.
    Notizen: Summary Leydig and Sertoli cells of the testis of the Pekin duck were studied ultrastructurally during the spring phase of the sexual cycle, from January to July. Simultaneously, in the same animals, Δ5-3 β-hydroxysteroiddehydrogenase (Δ5-3 β-HSDH) activity was ascertained histochemically and androgenic steroids of the plasma and testes were assayed by gas-liquid chromatography. The Leydig cells of the duck possess cytoplasmic organelles specific to steroidogenic cells (smooth reticulum, tubular mitochondria) as well as other structures often found in this cell type (microfilaments, vacuoles, denses bodies). The Sertoli cells contain an agranular reticulum that is less developed than that of the Leydig cells, and rarely show mitochondria with tubular cristae. These various cytoplasmic organelles undergo a seasonal cycle. The differentiation of the smooth reticulum and the mitochondrial tubular cristae begins in January and reaches a maximum in March. They begin to regress in April, at first with transitory degenerative structures, and then by total disappearance of these organelles by May. No indication of necrosis is observed in the cells. Histochemically Δ5-3 β-HSDH activity is present in the Leydig cells, and to a slightly lesser degree in the seminiferous tubules. The intensity varies during the cycle. The comparison of the results of the morphological study with the hormone assays shows that a good correlation exists with the development and regression of the smooth endoplasmic reticulum and tubular cristae in the mitochondria, as well as the histochemical criteria of the Δ5-3 β-HSDH on one hand, and the levels of plasma and testicular testosterone on the other hand. In addition there is an increase in the ratio of testicular testosterone to Δ4-androstenedione which parallels the development of the cytoplasmic organelles. These organelles thus seem to be implicated in the synthesis and secretion of testosterone in the duck.
    Materialart: Digitale Medien
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  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 144 (1973), S. 453-466 
    ISSN: 1432-0878
    Schlagwort(e): Lacrimal gland ; Rat ; Duct system ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The duct system of the rat exorbital lacrimal gland consists of intercalated ducts, interlobular ducts and excretory ducts. The morphological changes from one type of duct to the next are gradual. At the light microscopical level this consists of a change from a bilaminar epithelium in the intercalated ducts to an epithelium, consisting of approximately three layers — which may be pseudostratified — in the excretory ducts. The basal layer of the intercalated ducts consists of myoepithelial cells, whereas the inner epithelial cells may have both a secretory and an electrolyte transporting function. The interlobular duct epithelium contains many cells with deep infoldings of the basolateral plasma membranes and associated mitochondria, suggesting a similar function to the striated duct epithelium in salivary glands. Numerous basal cells in this epithelium have tentatively been interpreted as unusual myoepithelial cells. Nerve terminals have been observed in the ductal epithelium.
    Materialart: Digitale Medien
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  • 65
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 144 (1973), S. 475-487 
    ISSN: 1432-0878
    Schlagwort(e): Luteal cells ; Luteinization ; Endoplasmic reticulum ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Hyrax possess luteal cells with many ultrastructural features similar to those described in other mammalian species. The process of luteinization is gradual. Cells with increasing amounts of smooth endoplasmic reticulum become predominant in the developing gland. The luteal cells of Procavia and Heterohyrax show many ultrastructural similarities. In both species the corpus luteum persists throughout pregnancy.
    Materialart: Digitale Medien
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  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 138 (1973), S. 557-567 
    ISSN: 1432-0878
    Schlagwort(e): Thrombocytes ; Thrombosthenin ; ATP ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of glycerol extracted thrombocyte models was studied before and after incubation with ATP and under the influence of Salyrgan as inhibitor of contraction. The contractile system of the thrombocytes—thrombosthenin—consists of a spatial network of 50 Å wide thrombosthenin A and 100–120 Å wide thrombosthenin M filaments. At rest, the contractile system is arranged in a marginal zone. The ATP-induced contraction led to a concentric condensation of the network which resulted in a central cluster of cell organelles and at a later stage, disruption of the plasma membrane and release of the thrombocyte granules. All these changes which also occur during the formation of the hemostatic plug in vivo are therefore attributed to the reaction of the contractile protein.
    Materialart: Digitale Medien
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  • 67
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 136 (1973), S. 111-120 
    ISSN: 1432-0878
    Schlagwort(e): Median eminence ; Rat ; Granular vesicles ; Ultrastructure ; Quantitative evaluation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In order to characterize different sub-zones in the palisade zone of the rat median eminence, quantitative ultrastructural parameters were applied to brains fixed in aldehyde-osmium tetroxide. The palisade zone has been subdivided in 4 successive sub-zones. Increasing numbers of granular vesicles (GV), especially those smaller than 110 nm, are observed from dorsal to ventral sub-zones. There also are more GV per unit area of nervous tissue in the perivascular than in the more dorsal sub-zones. The individual nerve profiles exhibit a larger size in the perivascular layer than in the more dorsal areas, whereas the number and size of nerve profiles devoid of vesicles diminish from dorsal to ventral. As a consequence more GV occur in the perivascular nerve profiles. In the GV containing nerve profiles the concentration of GV is, however, constant in the different sub-zones. A fluctuating size of the preterminal and terminal parts of the nerve fibres is suggested.
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  • 68
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 136 (1973), S. 121-137 
    ISSN: 1432-0878
    Schlagwort(e): Cheliceral gland ; Opiliones ; Enveloping cells ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 1. Nemastoma dentigerum Canestrini besitzt als sekundäres männliches Geschlechtsmerkmal eine Apophyse auf dem ersten Chelicerenglied, die eine Drüse enthält. 2. Die einzelnen Drüsenzellen schließen sich jeweils zu Dreiergruppen zusammen, deren distales Ende immer von 3 Hüllzellen umfaßt wird. Diese 6 Zellen bilden eine funktionelle Einheit innerhalb des komplexen Drüsenorgans. Jede Drüsenzelle gliedert sich in 3 Abschnitte: 1. in den basalen kernhaltigen Teil, 2. in den mittleren sehr langen Drüsenzellschlauch und 3. in den distalen Kopf mit Mikrovilli-Becher. 3. An der Sekretion beteiligen sich 2 Zelltypen: die 3 Drüsenzellen und die innere Hüllzelle (H1). Das Sekret beider Zelltypen gelangt in ein gemeinsames Reservoir, das von H1 gebildet wird, und von dort durch Hämolymphdruck in den gewinkelten Cuticulin-Ausführkanal und auf die Außenseite der Apophyse. 4. Die Hüllzellen werden mit den 3 Hüllzellen der Haarsensillen von Insekten und Arachniden verglichen. Für H1 läßt sich eine gemeinsame Aufgabe nachweisen. Die beiden anderen Hüllzellen (H2 und H3) nehmen bei beiden Organen unterschiedliche Aufgaben wahr: Abscheidung von Haar und Balg (Haarsensillen) bzw. überwiegend Stützfunktion (Chelicerendrüse).
    Notizen: Summary 1. Nemastoma dentigerum Canestrini possesses as a secondary male sex character an apophysis on the first member of chelicerae. The apophysis contains a gland. 2. The single gland cells always join as groups of three cells whose apices are embraced by three enveloping cells. These six cells operate as a unit within a complex gland organ. Every gland cell is divided into three parts: 1. a basal section containing the nucleus; 2. a central very long section of the gland cell tube, and 3. an apex of the gland cell with a cavity containing microvilli. 3. Two types of cells of a gland unit secrete: the gland cells proper and the inner enveloping cell (H1). Secretion of both types of cells flows in a common reservoir surrounded by H1 and further through the bent channel to the surface of the apophysis by pressure of hemolymph. 4. The enveloping cells are compared with those of hair sensilla of insects and arachnids. A common function of H1 in both organs is pointed out. Central (H2) and outer enveloping cell (H3) work in a different way: secretion of hair and follicle (hair sensilla) and probably only supporting function (cheliceral gland).
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  • 69
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 137 (1973), S. 541-551 
    ISSN: 1432-0878
    Schlagwort(e): Muscles ; Insects ; Extracellular substance ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Im Stroma von Aorta und Retrocerebralkomplex sowie von verschiedenen Muskeln (Oberschenkel-, Mitteldarm-, Speicheldrüsen-, Samenleiter- und Eileitermuskeln), jedoch nicht im Stroma der Flugmuskulatur und des Herzschlauches, kommt eine fibrillär strukturierte Substanz (X-Substanz) von außerordentlich hoher Elektronendichte vor. In der Aorta, wo die größten Mengen an X-Substanz gefunden wurden, tritt besonders in den Muskelzellen älterer Tiere im Sarcoplasma und an der Plasmamembran eine körnige Substanz mittlerer Elektronendichte auf, welche auf Grund morphologischer Ähnlichkeit als Z-Material gedeutet wurde. Offenbar entsteht die X-Substanz, die in ihrer typischen Erscheinungsform nur extrazellulär beobachtet wurde, aus diesem Material. Da alte Tiere mehr X-Substanz aufweisen als jüngere, scheint es sich um die Abscheidung eines Altersprodukts zu handeln. Herkunft und Aussehen lassen ein langkettiges Protein vermuten. Muskeln, in denen X-Substanz vorkommt, enthalten auch viele Axone mit Neurosekreten; jedoch lassen sich bislang keine näheren Beziehungen zwischen diesen beiden Faktoren herstellen. Die X-Substanz wird offensichtlich vom Stroma weitertransportiert und wahrscheinlich von Blutzellen aufgenommen.
    Notizen: Summary A fibrous substance (X substance) of exceptionally high electron density is found in the stroma of aorta, retrocerebral complex, and several muscles (leg, midgut, salivary glands, vas deferens and oviduct), but not in the stroma of flight muscles and heart. The aorta, where the largest amount of X substance occurs, shows within the muscle cells, especially of older animals, a granular substance of moderate electron density in the sarcoplasm and adjacent to the plasma membrane. On account of its morphological similarity this material is considered as Z material. The X substance, which in its typical appearance was seen only extracellularly, seems to be derived from this granular Z material. Since old animals show more X substance than younger ones, it appears to be an aging product. Its origin and appearance point to a protein with long chain structure. Muscles containing much X substance show many neurosecretory fibers. However, no tangible relationship between these two parameters has been established. The X substance is evidently transported by the stroma and probably taken up by hemocytes.
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  • 70
    ISSN: 1432-0878
    Schlagwort(e): Protozoa ; Bacteria ; Association ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of Cyclidium, including the cilia, kinetosomes, pellicle, microtubules and kinetodesmal fibers is similar to that recorded for other ciliates. Of special interest is the attachment of rod-shaped bacteria within the longitudinally directed shallow surface folds of the protozoan. Both the bacteria and the surface of Cyclidium seem to possess an outer coating of a sticky substance which upon contact holds the bacteria to the protozoan. The bacteria appear to be attached by only a relatively small area of their surfaces. A dense substance appears within the alveolus of the pellicle at the regions of the attachment of the bacteria. The association of the organisms is probably a temporary one, and it is unknown whether either organism is benefited or harmed by the association. The position of the mitochondria in Cyclidium is unusual in that they all lie flattened against the inner membrane of the pellicle, usually in a position directly opposite to that of the attachment of the bacteria to the surface, thus being separated from the bacteria by only the outer cell membrane and the pellicle. Whether or not this close topographical relationship is of significance is unknown.
    Materialart: Digitale Medien
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 139 (1973), S. 351-368 
    ISSN: 1432-0878
    Schlagwort(e): Lateral giant cells ; Dorsal giant fibres ; Earthworm, Lumbricus terrestris L. ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Feinstruktur der segmental angeordneten Somata der dorsalen Riesenfasern im Bauchmark des Regenwurms Lumbricus terrestris L. (Günther, 1969) wird beschrieben und mit der Struktur anderer Neuronen von Vertebraten und Evertebraten verglichen. Die paarigen lateralen Riesenzellen (LRZ) sind im Gegensatz zu der unpaaren medianen Riesenzelle (MRZ) häufig multipolare Neuronen, die bis zu vier Faserfortsätze aufweisen können. Das perikaryale Cytoplasma zeigt helle und dunkle Areale. Organellen und andere Zelleinschlüsse finden sich ganz überwiegend in den dunklen osmiophilen Zonen und lassen regelmäßig eine bestimmte Anordnung erkennen. So ist häufig eine ringförmige Verteilung von Golgi-Feldern um den gelappten Kern vorhanden. Mitochondrien sind häufig in einem typischen „Axonhügel-Komplex“ angeordnet. Freie Ribosomen dominieren gegenüber membrangebundenen. Diese Neuronen sind reich an Glykogen, das oftmals ausgedehnte Felder einnimmt. Vereinzelt weisen die LRZ Faser-Soma-Synapsen auf.
    Notizen: Summary The structure of the segmentally arranged somata of the dorsal giant fibres Günther, 1969) in the ventral nerve cord of the earthworms Lumbricus terrestris L., is described. These neurones are compared with other neurones of invertebrates and vertebrates. The paired lateral giant cells (LGC) are often multipolar in contrast to the single unipolar median giant cell (MGC). Up to four fibres originate from each LGC. The dotted appearance of both these neurones (clear and dark perikaryal areas) is due to the regular distribution of osmiophilic strands of cytoplasm containing the majority of organells and other inclusions (e.g. endoplasmatic reticulum and ribosomes). The majority of ribosomes are not associated with membranes but are found scattered freely in the cytoplasm. A typical “axon hillock” with an accumulation of mitochondria is often found. The cells show large deposits of glycogen. Some of the LGC-somata have synaptic contacts.
    Materialart: Digitale Medien
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  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 138 (1973), S. 239-259 
    ISSN: 1432-0878
    Schlagwort(e): Ovary ; Gastropoda ; Oocytes ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Oocyten von Viviparus contectus gehören zu den kleinsten, bei Mollusken bekannten Oocyten und enthalten nur wenig Dotter. Nach licht- und elektronen-mikroskopischen Untersuchungen kann die Oogenese in drei Stadien eingeteilt werden. Oocyten des ersten Stadiums zeichnen sich durch das Vorkommen extrem polymorpher Kerne, durch annulate lamellae und schüsselförmige Mitochondrien aus. Große, konzentrisch geschichtete Systeme des granulären endoplasmatischen Retikulums und ein gut entwickelter Golgi-Apparat sind typisch für Oocyten des zweiten, prävitellogenetischen Stadiums. Oocyten dieses Stadiums enthalten außerdem große Nukleolen und andere Kerneinschlüsse unbekannter Funktion, deren Ultrastruktur beschrieben wird. Diese Einschlüsse werden mit dem sog. Binnenkörper der Insekten verglichen. Oocyten des dritten Stadiums, der Vitellogenese, enthalten zahlreiche paraplasmatische Einschlüsse wie dense bodies, Multivesikulärkörper und polymorphe Cytosomen, Fetttropfen und Glykogen. Dense bodies, Multivesikulärkörper und polymorphe Cytosomen enthalten Massen eines Ferritin-ähnlichen Eisenproteins und saure Phosphatasen. Das endoplasmatische Retikulum und der Golgi-Apparat sind an der Dottersynthese beteiligt. Die extrem geringe Größe der Oocyten und ihr Mangel an Dotter dürfte mit der Viviparie der Tiere in Zusammenhang stehen. Da die Eiweißdrüse und Drüsenzellen des Oviduktes große Mengen sekundären Dotters liefern, ist zu vermuten, daß die Oocyte mit ihrer niedrigen Transkriptionskapazität zusätzlich mit nur wenigen wichtigen Substanzen wie lytische Enzyme für den Beginn der Embryogenese und Eisenprotein ausgestattet wird. Viele Oocyten degenerieren im Ovar. Die mit der Degeneration einhergehenden Veränderungen der Ultrastruktur werden beschrieben.
    Notizen: Summary The oocytes of Viviparus contectus belong to the smallest oocytes known in molluscs and contain relatively small amounts of yolk. As shown by light- and electron microscopy, oogenesis can be divided into three stages. Oocytes of the first stage are characterised by the occurrence of extremely polymorphic nuclei, of annulate lamellae and cup-like mitochondria. Large systems of rough endoplasmic reticulum, arranged concentrically and a well developed Golgi apparatus are typical for oocytes of the second, the previtellogenetic stage. Oocytes of this stage also contain large nucleoli and other nuclear inclusions of unknown function, whose ultrastructure is described. These inclusions may be compared with the so called “Binnenkörper” of insects. Oocytes of the third stage, the vitellogenesis, contain a large amount of paraplasmic inclusions such as dense bodies, multivesicular bodies and polymorphic cytosomes, fatty yolk droplets and glycogen. Dense bodies, multivesicular bodies and polymorphic cytosomes contain masses of a ferritin-like iron protein and acid phosphatases. It is supposed that the endoplasmic reticulum and the Golgi apparatus are engaged in yolk production. The extremely small size of the oocytes and their lack in yolk should be seen in connection with the vivipary of the animals. As there are large amounts of secondary yolk provided by the albumen gland and glandular cells of the oviduct, it is supposed that the oocyte having a low transcription capacity needs to be supplied, in addition, with only few essential substances such as lytic enzymes for the early stages of embryogenesis and iron protein. Many oocytes usually degenerate inside the ovary. The changes in ultrastructure during the degeneration are described.
    Materialart: Digitale Medien
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  • 73
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 138 (1973), S. 315-326 
    ISSN: 1432-0878
    Schlagwort(e): Olfactory mucosa ; Frog ; Innervation ; Ultrastructure ; Light and electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The olfactory mucosa of frog has been studied at an ultrastructural level to confirm previous light microscope observations in regard to the presence, in the sensory epithelium, of nerve fibres not belonging to the first cranial nerve proper. It has been observed that both myelinated and unmyelinated nerve fibres are present in the lamina propria and that eventually these fibres terminate inside the epithelium. Unmyelinated fibres usually contain dark core vesicles and similar content is seen in their intraepithelium terminals. Terminals containing only clear vesicles are also observed in the epithelium and they are believed to represent the terminals of the myelinated fibres. The significance of these ultrastructural findings is discussed in view of their functional meaning.
    Materialart: Digitale Medien
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  • 74
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 138 (1973), S. 475-488 
    ISSN: 1432-0878
    Schlagwort(e): Synaptogenesis ; Spinal cord ; Chick embryo ; Coated vesicles ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Synaptogenesis was studied in 3, 4, 5 and 8 day embryos. A small number of synapses were located in the marginal zone near the motor region in 3–4 day embryos. At 5 days the number of synapses increased and synapses were also found within the motor region. At 8 days there was a large increase in the total number of synapses and most were found within the motor region. At this stage, for the first time, many knobs contained flattened synaptic vesicles. Synapses on the perikarya were rarely but occasionally observed both at the 5 and 8 day stages. A few synapses were located in the marginal zone near dorsal root entry at the 5 day stage and the number increased by the 8 day stage. Although this sequence of synaptic development resembles that found in the monkey fetus, differences in behavioral development between these two species indicate that descriptive relationships between synaptic and behavioral development must be made cautiously. Furthermore, evidence is presented which indicates that the junctional specialization is the first sign of a developing synapse and that coated vesicles, possibly derived from the Golgi apparatus, which are fused to the neural plasmalemma may be related to the initial formation of the junctional specialization.
    Materialart: Digitale Medien
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  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 140 (1973), S. 309-314 
    ISSN: 1432-0878
    Schlagwort(e): Pituitary Gland ; Rat ; Somatotropin ; Cellular Response ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The response of somatotrophs to large doses of purified bovine growth hormone was examined in uninephrectomized rats drinking 1% sodium chloride in an attempt to prolong the action of the hormone. Growth hormone produced a triphasic response in the ultrastructure of somatotrophs. Uninephrectomy and salt alone induced no changes in somatotrophs as compared to unoperated animals consuming tap water. In the first phase (3 days) the cross sectional area of the cell increased, the size of the largest granule per cell as well as the number of granules per cell increased significantly. All these parameters then reached control level after 7 days of injections during a second phase. Suppression of somatotrophs by exogenous growth hormone was evident by 16 days (third phase) when the area of the cell, the size of the largest secretory granule as well as the number of granules per cell all decreased significantly. Somatotrophs apparently did not react to suppression by a lysosomal mechanism inasmuch as no increase in the number of lysosome-derived structures was seen even at 16 days.
    Materialart: Digitale Medien
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  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 141 (1973), S. 545-560 
    ISSN: 1432-0878
    Schlagwort(e): Pineal gland (Rabbit) ; Light and dark pinealocytes ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In the rabbit pineal gland a cortex and a medulla can be distinguished, based on the distribution pattern of two cell types. The medulla consists of so-called light and dark pinealocytes, whereas in the cortex only light ones occur. The cytological distinction between the two cell types is principally due to the exclusive presence of abundant pigment granules in the dark pinealocytes. The light pinealocytes have long offshoots. Their club-shaped terminals are crowded with smooth endoplasmic reticulum from which grey vesicles are pinched off. In the medulla, these offshoots run for the most part into the direction of blood vessels to terminate in close topographical relationship with dark pinealocytes which are mainly arranged around these vessels. The ultrastructure of both the light and the dark pinealocytes is described.
    Materialart: Digitale Medien
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  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 143 (1973), S. 169-182 
    ISSN: 1432-0878
    Schlagwort(e): Insecta Tysanura Machilida ; Protrusible (coxal) vesicles ; Water absorption ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Les Machilides présentent une série de vésicules abdominales paires, sous forme de sacs exsertiles capables d'absorber l'eau d'un film liquide. Les coupes histologiques montrent qu'une partie de la paroi de ces vésicules est faite d'un épithélium particulier revêtu d'une intima cuticulaire plus épaisse que celle de l'épithelium banal. La microscopie électronique permet de préciser la structure des cellules absorbantes qui sont caractérisés essentiellement par des microvillosités apicales et de profondes invaginations de la membrane plasmique basale associées à des mitochondries allongées. Une comparison est faite avec d'autres types de cellules absorbantes connues chez les Arthropodes, notamment dans le rectum. Grâce à leurs vésicules abdominales, les Thysanoures possèdent des organes originaux jouant un rôle important dans l'équilibre hydrique de ces insectes.
    Notizen: Summary The Machilida are endowed with several abdominal vesicles which are protrusible sacs capable of absorbing water from the substrate surface. Histology shows that a part of their outer wall consists of a particular epithelium covered by a cuticular intima, which is thicker than the intima of the common epithelium. The absorbing cells are electronmicroscopically characterized by apical microvilli and deep infoldings of the basal plasma membrane which are associated with mitochondria. A comparison is drawn with other types of absorbing cells already known, especially with those in the rectum of insects. Thanks to their abdominal vesicles, the Thysanura possess unique organs which play an important role in the control of their water balance.
    Materialart: Digitale Medien
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 143 (1973), S. 183-206 
    ISSN: 1432-0878
    Schlagwort(e): Sensilla ; Olfaction ; Dictyoptera (insect) ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Les organes sensoriels du scape et du pédicelle sont essentiellement propriocepteurs. Le fouet est très riche en chimiorécepteurs (plus de 100000) mais chez Periplaneta et Blatta, on observe un net dimorphisme sexuel qui n'existe pas chez Blaberus. La relation entre un tel dimorphisme et la perception des phéromones sexuelles est discutée. L'ultrastructure des trois principaux types de sensilles est décrite: Ce sont des grandes soies gustatives et mécanoréceptrices, des petites soies olfactives à paroi mince et percée de pores et de tubules qui sont innervées par un ou deux neurones, des petites soies olfactives à paroi épaisse et striée qui contiennent toujours quatre neurones. L'étude électrophysiologique préliminaire confirme les résultats ci dessus en ce qui concerne le rôle des sensilles: La phéromone grégaire peut être perçue au niveau de certaines petites soies olfactives striées.
    Notizen: Summary The antennae of cockroaches were studied with both scanning and transmission electron microscope. The sense organs of the scape and pedicel are essentially proprioceptors. The chemoreceptors are very numerous on the flagellum (more than 100000) but in the case of Periplaneta and Blatta, a significant sexuel dimorphism is noticed. Such a dimorphism does not exist in Blaberus and its relation with the perception of the sexual attractants is discussed. Three principal sense organs of Blaberus are described: big thick walled hairs with gustatory and mechanoreceptive function; thin walled olfactory hairs with pore-tubules innervated by one or two neurons; thick walled grooved hairs with four neurons and olfactory function. Special attention was given to the secretory aspect of the accessory cells in the olfactory sensilla. A preliminary electrophysiological investigation confirms the above mentioned functional interpretations. The gregarious pheromone seems to be perceived by some little thick walled grooved hairs.
    Materialart: Digitale Medien
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 143 (1973), S. 207-227 
    ISSN: 1432-0878
    Schlagwort(e): Testis interstitial cells ; Boar ; Postnatal development ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die postnatale Ontogenese der Hodenzwischenzellen des Schweins nimmt einen wellenförmigen Verlauf und läßt sich in 4 Phasen unterteilen. In der frühpostnatalen Proliferationsphase wandeln sich spindelförmige Zellen in polygonale Leydigzellen um. Dabei beginnt an einem Zellpol die Ausbildung des glatten endoplasmatischen Retikulums. Dieses Organell nimmt in der weiteren Entwicklung einen großen Teil des Zelleibes ein und bildet unregelmäßige Vesikel und konzentrisch geschichtete Zisternen. Es erfolgt eine Vermehrung der Mitochondrien, in ihnen entwickeln sich Tubuli. In der Phase der präpubertären Hypertrophie erreichen die Leydigzellen ihre größten Durchmesser (ca. 30 μm) und sind möglicherweise zu einer Steroidhormonproduktion befähigt. Da das glatte endoplasmatische Retikulum vornehmlich in der Zellperipherie, die übrigen Organellen bevorzugt im Zentrum liegen, sind die Zwischenzellen deutlich zoniert. Die Phase der präpubertären Regression ist durch ausgeprägte Zelldegeneration und Größenabnahme der überlebenden Zellen gekennzeichnet. In der Phase der pubertären Proliferation nehmen die Zwischenzellen erneut an Größe zu. Parallel hierzu vermehren sich Mitochondrien und glattes endoplasmatisches Retikulum. Beide Proliferationsphasen innerhalb der postnatalen Ontogenese werden durch das Auftreten zahlreicher Cytoplasmafilamente eingeleitet, deren Menge sich danach wieder verringert. Unabhängig von dem wellenförmigen Verlauf der Zwischenzellentwicklung ist die Ausbildung von Lysosomen, Microbodies, Mikrovilli, typischen Zellhaften und in der Zellperipherie gelegenen Polyribosomen. Die Leydigzellen sind von einer basalmembranähnlichen Struktur umgeben. Die Mitochondrien enthalten zu allen Zeiten durch elektronendichtes Material verkittete Tubuli.
    Notizen: Summary The postnatal development of porcine testicular interstitial cells proceeds in a wave-like manner and may be divided into four periods. In the period of early postnatal proliferation fusiform intertubular cells change into polygonal Leydig cells. This process starts with formation of smooth endoplasmic reticulum in one of the cell poles. Later the smooth endoplasmic reticulum is abundant and consists of irregular vesicles and concentrically arranged cisterns. Mitochondria increase in number and develop tubular cristae. In the period of prepubertal hypertrophy Leydig cells reach maximal size (approx. 30 μm) and possibly may be capable of androgen biosynthesis. The cells of this period exhibit two different zones, since the smooth endoplasmic reticulum prefers the periphery, the other organelles, however, occupy the central region of the cells. The period of prepubertal regression is characterized by cellular degeneration and diminuation of the surviving interstitial cells. In the period of pubertal proliferation an increase of Leydig cell size is accompanied by multiplication of mitochondria and development of smooth endoplasmic reticulum. Both periods of proliferation are initiated by appearance of numerous cytoplasmic filaments which subsequently decrease in number. Interstitial cells of all periods studied exhibit the following features: They possess lysosomes, microbodies, polyribosomes, microvilli and are surrounded by a kind of basement membrane. Cell connections appear as tight junctions and desmosome-like structures. The mitochondria contain closely packed tubules joined by electron dense material.
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  • 80
    ISSN: 1432-0878
    Schlagwort(e): Nervous tissue ; Specific structures ; Nematosomes ; Neurofilaments ; Neurotubules ; Three-dimensional filamentous network ; E-PTA Stain ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary After the staining of nervous tissue with phosphotungstic acid in absolute ethanol (E-PTA), a selective opacification occurs at certain specific sites, while other structures, especially the plasma and intra-cellular membranes, remain electron-lucent. Among those selectively stained sites, our studies have been focussed on: (1) The dense synaptic material consisting of several presynaptic clumps, termed projections, an intrasynaptic dense line and a subsynaptic web from which fine fibrillar wisps extend into the surrounding ground substance; (2) Neurofilaments and neurotubules, the surface of which is bristled by numerous side-arms; (3) A microfilamentous network intertwines the neurotubules, the neurofilaments and the mitochondria in the dendrites and axon, and is also connected to the E-PTA dense undercoating delineating the inner aspect of the plasma membrane and to the fine wisps emanating from the subsynaptic web. A three-dimensional microfilamentous latticework is thus formed in the nerve cell processes; (4) Dense cytoplasmic inclusions, termed nematosomes, which are usually located in the ground substance of the perikaryon among or in the vicinity of clusters of ribosomes. Tiny microfilaments emanate from the peripheral strands of these bodies. The presence of basic residues in the chains of structural proteins of which consist the subsynaptic web and the nematosome is plausible, since the specificity of the E-PTA staining procedure for the detection of basic residues has previously been put forth. The occurrence of a three-dimensional microfilamentous network in the nerve cell processes led us to hypothesize that it plays a role in translocation of materials. It may provide the motive force for the axoplasmic transport, for instance, with the neurotubules, as well as, plausibly, with the neurofilaments, serving as attachment sites and guideways.
    Materialart: Digitale Medien
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  • 81
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 143 (1973), S. 569-586 
    ISSN: 1432-0878
    Schlagwort(e): Fish (Macropodus opercularis) ; Muscle Origin ; Myofilaments ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Am Beispiel der Muskulatur von Macropoden wird gezeigt, wie sich aus undifferenzierten Zellen ein Verband gleichartig differenzierter Zellen aufbaut. Einkernige Praemyoblasten ohne Myofilamente bilden sich zu mehrkernigen Myoblasten um. In diesen erscheinen die ersten Myofilamente in streng geordneter Weise: parallel zur Zellmembran und in deren Nähe entstehen Myofilamente unterschiedlicher Länge, wobei Aktin und Myosin etwa gleichzeitig auftreten. Das Z-Scheiben-Material konnte in sehr frühen Stadien erkannt werden. Polysomen stehen in enger räumlicher Beziehung zu den sich ausbildenden Myofilamenten. Vorwiegend in der Zellperipherie entwickeln sich die Myofibrillen aus sog. „crude sarcomeres“. Sie zeigen noch nicht die charakteristische Einteilung in A-und I-Bänder. Im Verlauf der weiteren Entwicklung richten sich die Z-Scheiben parallel zueinander aus und die A- und I- sowie H- und M-Bänder erscheinen in ihrer definitiven Form. Ein Dickenwachstum des Muskels kann dadurch entstehen, daß noch vorhandene Praemyoblasten sich in charakteristischer Form ausdifferenzieren und den Muskel durch Apposition von Myofibrillen marginal verstärken.
    Notizen: Summary During ontogenesis of the fish, Macropodus opercularis, uninucleated praemyoblasts without any myofilaments fuse to form multinucleated myoblasts. Within the myoblasts, parallelly and longitudinally arranged myofilaments of different lengths appear close to the cell membrane and in close relation to polysomes. Actin and myosin are detectable in the filamentous form at approximately the same time. This process of sarcomere differentiation starts from so-called “crude sarcomeres” lacking the characteristic arrangement in A-and I-bands. Subsequently, Z-disks are arranged parallel to each other, and A- and I-bands as well as H- and M-bands appear in their definite forms. There are indications that the muscle fibre grows in thickness by additional fusions with still existing praemyoblasts and marginal apposition of further myofibrils.
    Materialart: Digitale Medien
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 145 (1973), S. 447-458 
    ISSN: 1432-0878
    Schlagwort(e): Corpus allatum ; Oncopeltus fasciatus ; Larvae ; Imagines ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary 1. The ultrastructure of the corpora allata of last larval instars and adults of Oncopeltus was studied. The unpaired gland undergoes submicroscopic alterations and shows signs of degradation in old animals. The organ is partly covered and penetrated by corpus cardiacum tissue. Axons with different types of neurosecretory granules form synaptoid contacts with the corpus allatum cells. 2. “Dark” and “light” gland cells can be differentiated on account of the degree of electron density. The former predominate during the last larval stage and in the young imago, the latter in mature males and females. It is highly probable that the “light” cells are the active (i.e. hormone producing) ones and the “dark” cells the inactive ones. 3. The active cells are characterized by rough endoplasmatic reticulum (often in whorls), small amounts of smooth endoplasmatic reticulum and many multivesicular bodies. Abundant free ribosomes, a not particularly well developed Golgi apparatus, dense bodies, and cytolysomes are present in active and inactive cells. 4. The nuclei contain one to four prominent and variously shaped nucleoli, which show differences between adult males and females with respect to their location in the nucleus. 5. The corpus allatum cells of Oncopeltus are obviously engaged in extensive protein synthesis. Tangible structural indications for the manufacture of juvenile hormone were not observed. Possible sites of hormone release are discussed.
    Materialart: Digitale Medien
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  • 83
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 146 (1973), S. 167-175 
    ISSN: 1432-0878
    Schlagwort(e): Parathyroid ; Secretory cycle ; Winter frog ; Ultrastructure ; Pituitary homoimplantation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Parathyroid glands of winter frogs (Rana pipiens) were compared by light and electron microscopy with those of winter frogs homoimplanted with pituitary glands. Serum calcium levels of untreated and pituitary-implanted animals were compared also. Forty-eight hours after pituitary implantation, serum calcium is elevated from a mean winter value of 6.2 mg % to 9.3 mg % and, morphologically, the parathyroid gland appears to be stimulated with respect to secretory activity. Compared with parathyroids of untreated winter frogs, intercellular spaces are diminished after pituitary implantation and glandular parenchyma is composed of cells with closely apposed plasma membranes thrown into interdigitating folds. Dense core vesicles are present in the cytoplasm and, together with microtubules, are encountered near plasma membranes. Golgi lamellae contain electron dense material and exhibit budding of dense core vesicles. Neither myelinated multivesicular bodies, presumably cytolysosomes degrading unneeded parathormone and organelles, nor focal dilatations with myelination of Golgi lamellae are encountered in parathyroid cells of pituitary implanted frogs. Rough endoplasmic reticulum and mitochondria do not undergo marked changes in distribution or abundance after pituitary implantation, indicating that the synthetic aspects of the secretory process are little altered in untreated and treated animals. It is suggested that in addition to Ca++ a pituitary factor is involved in the seasonal changes in amphibian parathyroid structure and function.
    Materialart: Digitale Medien
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  • 84
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 146 (1973), S. 375-384 
    ISSN: 1432-0878
    Schlagwort(e): Muscle ; Fish ; Starvation ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The effect of 16 weeks total starvation on the ultrastructure of the red and white myotomal muscles of the crucian carp (Carassius Carassius) has been investigated. In the white fibres the amount of myofibrillar material fell from 89.6% to 70.7% of the total fibre volume whilst in the red fibres the fall was from 72.2% to 70.3%. The sarcoplasmic reticulum appeared to have become swollen during starvation in both fibre types. In the white fibres the terminal cisternae of some triads seem to have fused. The volume of the red fibres occupied by mitochondria was reduced from 16.2 % to 5.9 %. The concentration of mitochondria in the white fibres was too low to detect any quantitative changes. A marked reduction in the amount of euchromatin material was observed in most white fibre nuclei and many red fibre nuclei. Many of the ultrastructural changes noted in the present study can be correlated with biochemical changes known to occur in the red and white myotomal muscles of fish during starvation.
    Materialart: Digitale Medien
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  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 144 (1973), S. 11-29 
    ISSN: 1432-0878
    Schlagwort(e): Spermatozoon ; Prosobranchia (Littorina) ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The filiform spermatozoon of Littorina contains a conical acrosome positioned anteriorly to the nucleus. The nucleus is essentially a tube of condensed chromatin surrounding the flagellar shaft and only the apical third is covered by a nuclear envelope. A structure resembling a basal body, which is either a modified proximal centriole, or a derivative of the distal centriole, terminates in a basal plate at the tip of the nucleus. Distally it gives rise to the nine outer flagellar doublets, which are continuous with the outer fibres of the distal centriole located 0.26 μ behind the “basal body”. Thus the “basal body” and distal centriole are lined up with each other and the axis of the flagellum. A supernumerary tubule connects the outer arm of the A subfibre of doublet 5 with the “basal body”. The flagellar shaft extends from the apex of the nucleus to the tip of the tail. In the mitochondrial region the plasmalemma fuses with the outer mitochondrial sheath to form a series of pores that connect the mitochondria directly with the external environment. A distinct joint separates the mitochondrial and tail regions enabling the tail to beat perpendicularly to the main flagellar axis. The last section of this paper is given to a discussion of sperm motility in the light of these structural observations.
    Materialart: Digitale Medien
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  • 86
    ISSN: 1432-0878
    Schlagwort(e): Dense core vesicles ; Ultrastructure ; Mollusc ; Nervous system ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Electron microscopy of the cerebro-visceral connectives of Anodonta cygnea shows numerous long rows of dense core vesicles within the smaller axons of the connectives. These vesicles are often linked together by bridges of electron-dense material reinforced by one or more “arms”. The use of the tilting stage on the electron microscope, which allows the bridges to be examined from different angles, confirms the presence of these vesicular connections. Sub-cellular fractionation of the cerebro-visceral connectives was carried out to study the nature of these bridged dense core vesicles. In the negatively stained vesicle fraction two or more dense core vesicles are joined in a row by connections similar to the vesicular bridges of the intact connective. In the fixed vesicle fraction, many of the dense core vesicles are connected by bridges but long rows of bridged vesicles are not seen. The functional significance of the vesicular bridges is discussed. Preliminary findings of this work have been reported previously (McLaughlin and Howes, 1973).
    Materialart: Digitale Medien
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  • 87
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 144 (1973), S. 139-152 
    ISSN: 1432-0878
    Schlagwort(e): CSF contacting axons ; Ependymal synapses ; Pineal organ ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Im Lumen des Pinealorgans können frei verlaufende, nackte Axone (Durchmesser 2000–7000 Å) beobachtet werden. Ihr Axoplasma enthält Mikrotubuli, Mitochondrien, synaptische (Durchmesser 350–450 Å) und granulierte Vesikel (Durchmesser 500–1500 Å). Bei Pleurodeles waltlii bilden die im Lumen des Pinealorgans verlaufenden Axone Synapsen auf der freien, apikalen Oberfläche der pinealen Ependymzellen. In den innervierten Ependymzellen kommen neben sonstigen Zytoplasmabestandteilen Myeloidkörper und Anhäufungen von Glykogengranula vor. Die Axone verlaufen am Innen- und Außenglied der Pinealozyten vorbei, können diese berühren, bilden aber dort keine Synapsen. Die auf den pinealen Ependymzellen nachgewiesenen Synapsen beweisen eine neuronale Kontrolle dieser Gliaelemente. Die Nervenfasern des pinealen Lumens wurden mit bekannten Liquorkontaktaxonen verglichen. Sie ähneln einander in ihrer Ultrastruktur und ihren synaptischen Verbindungen. Aus diesem Grunde und da bei den Amphibien das pineale Lumen mit dem 3. Ventrikel kommuniziert, werden die Axone des pinealen Lumens als Liquorkontaktaxone und als Glied des sogenannten Liquorkontakt-Axonsystems des Gehirns angesehen. Ferner wurden die pinealen Liquorkontaktaxone mit folgenden Nervenfasern und Endigungen verglichen, die im pinealen Gewebe vorkommen: 1) Axone, die große, granulierte Vesikel (Durchmesser 1300–1500 Å) enthalten und an den Dendriten von Nervenzellen endigen, welche zwischen den basalen Fortsätzen der Pinealozyten liegen; 2) Pinealozytenfortsätze, die synaptische Bänder enthalten und ebenfalls an diesen Neuronen Synapsen bilden; 3) die neurohormonalen, synaptischen Semidesmosomen von Pinealozytenfortsätzen an der Lamina basalis, die die bindegewebigen Räume der Pia mater vom eigentlichen Nervengewebe des Pinealorgans begrenzt: 4) die perivasalen, autonomen Nervenfasern der pialen Septen. Obwohl granulierte Vesikel verschiedener Durchmesser in allen diesen Terminalen vorhanden sind, stellten wir die größte, morphologische Ähnlichkeit zwischen den pinealen Liquorkontaktaxonen und denjenigen Nervenfasern fest, die große, granulierte Vesikel aufweisen und an den pinealen Neuronen axo-dendritische Synapsen bilden. Eine ähnliche Natur und Herkunft beider Axone werden angenommen.
    Notizen: Summary Free-running, naked axons (diameter 2000 to 7000 Å) can be found in the lumen of the pineal organ. Their axoplasm contains microtubules, mitochondria as well as synaptic (diameter 350 to 450 Å) and granulated vesicles (diameter 500 to 1500 Å). In Pleurodeles waltlii, the axons in the pineal lumen form synapses on the free, apical surface of the pineal ependyma which is supplied with microvilli. In addition to usual cytoplasmic elements the innervated ependymal cells contain myeloid bodies and accumulations of glycogen granules. Without forming synapses these axons pass by and occasionally contact the inner and/or outer segments of the pinealocytes. The synapses found on the pineal ependymal cells furnish evidence of a neuronal control of these glial elements. The nerve fibers of the pineal lumen are being compared with known CSF contacting axons; they resemble one another in their ultrastructure and synaptic connections. Therefore and since in amphibians the pineal lumen communicates with the 3rd ventricle, the axons of the pineal lumen are considered to represent CSF contacting axons and to belong to the so-called CSF contacting axon system of the brain. In addition, the pineal CSF contacting axons are being compared with the following nerve fibers and terminals found in the pineal tissue: 1) axons containing large, granulated vesicles (diameter 1300 to 1500 Å) and terminating on the dendrites of nerve cells situated among the basal processes of the pinealocytes; 2) the synaptic ribbons-containing pinealocyte processes forming likewise synapses on the nerve cells; 3) the neurohormonal, synaptic semidesmosomes of pinealocytic processes on the lamina basalis separating the connective tissue spaces of the pia mater from the proper nervous tissue of the pineal organ; 4) the perivasal, autonomic nerve fibers of the pial septa. Though granulated vesicles of various diameters are present in all these terminals the greatest morphological similarity is found between the pineal CSF contacting axons and those nerve fibers containing large, granulated vesicles and forming axo-dendritic synapses on the pineal nerve cells. A similar nature and origin of both axons are suggested.
    Materialart: Digitale Medien
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  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 144 (1973), S. 191-217 
    ISSN: 1432-0878
    Schlagwort(e): Nucleus infundibularis ventralis ; Hypothalamus ; Rana esculenta ; Gonadotropin releasing factor ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Ultrastructural evidence has been obtained for several nerve cells in the middle and posterior hypothalamus of Rana esculenta, which may be classified as neurosecretory cells. These cells belong to the nucleus infundibularis ventralis, being homologous to the nucleus infundibularis of higher vertebrates. According to the type of dense-core vesicles, two categories of neurosecretory cells were identified in the NIV, type Y and type Z cells. The morphology of these cells and the diameter of their dense-core vesicles suggests a peptidergic nature of the secretory product. Both cell types appeared as bipolar, liquor-contacting neurons, innervated by aminergic axons. The effects of castration and testosterone treatment on the Y cells of the NIV, as well as their localization in the caudal hypothalamus, suggest these cells to be involved in the regulation of the gonadotropic activity of the pars distalis. The presence in the zona externa of the median eminence of axon terminals containing the “Y type dense-core vesicles” is indicative of the release of their secretory product into the portal vessels.
    Materialart: Digitale Medien
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  • 89
    ISSN: 1432-0878
    Schlagwort(e): Hypophysis ; Mouse, rat ; Pars intermedia, rostral zone ; Corticotrophic cells ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In the mouse, the rostral zone of the pars intermedia is almost exclusively composed of typical corticotrophic cells. They are located around and even within the neural stalk, at the level of transition between stalk and neural lobe. In the rat, the corticotrophic cells of the rostral zone are found in scattered islets among the MSH producing cells, and also in the neural lobe. In both the rat and mouse, these cells are in direct contact with various types of nerve terminals. Synaptoid contacts with aminergic and neurosecretory nerve fibers are observed. Furthermore they are also closely related to the hypophysial portal vessels. Following adrenalectomy, the cells located in the neurohypophysis always react more intensely than tose in the rostral zone. The functional significance of these corticotrophic cells which are subject to both humoral and neural regulation remains as yet hypothetical. Their participation in neurogenic stress response seems probable.
    Materialart: Digitale Medien
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  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 137 (1973), S. 13-19 
    ISSN: 1432-0878
    Schlagwort(e): Urinary bladder (frog) ; Epithelial cells ; Osmotic pressure ; Oxytocin ; Water permeability ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The frog urinary bladder undergoes a marked increase in its water permeability when incubated in hypertonic media. Many similarities are found between this effect and the hydrosmotic action of antidiuretic hormone. The ultrastructural modifications of the epithelium observed under the influence of serosal hypertonicity (the intercellular spaces are dilated while the tight junctions remain closed) lead us to assume that the pathways of water movement across the epithelium could be the same in this case and in hydrosmotic response to the hormone. In contrast, when the mucosal medium is made hypertonic, the ultrastructure is differently altered: the intercellular spaces are closed, the tight junctions show small vesicles and numerous large vacuoles appearing in the cytoplasm.
    Materialart: Digitale Medien
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  • 91
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 136 (1973), S. 349-354 
    ISSN: 1432-0878
    Schlagwort(e): Intranuclear paracrystalline inclusions ; kidney ; Proximal tubule cells ; Canine ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Des inclusions intranucléaires paracristallines ont été mises en évidence dans les tubes proximaux de reins de chien. Ces inclusions sont constituées par une répétition régulière d'unités élémentaires microtubulaires de 85±15 Å de diamètre avec une périodicité de 120±20 Å. Elles ne sont jamais en contact ni avec le nucléole ni avec la membrane nucléaire. L'étude histochimique montre qu'il s'agit d'inclusions de nature protéique. Ces inclusions ont été observées à la fois dans les reins greffés (autogreffes) après conservation dans un perfusat artificiel (selon «Collins» ou «Perfudex») pendant 24 heures à 0°C et dans les reins normaux. N'étant jamais rencontrées au niveau de cellules rénales lésées, il ne semble pas que ces inclusions expriment une dégénérescence cellulaire.
    Notizen: Summary The occurrence of intranuclear paracrystalline inclusions in proximal tubules of the canine kidney is described. These inclusions are composed of a regular repetition of microtubular elementary units of 85±15 Å thickness with a periodicity of 120±20 Å. They have no contact with the nucleolus or the nuclear membrane. Histochemical findings suggest that these inclusions may be proteinaceous. They are both observed in grafted kidneys (autografts) after conservation during 24 hours at 0°C in a synthetic solution (according to “Collins” or “Perfudex”) and in normal kidneys. There were no signs of degeneration in cells containing such inclusions; therefore, the possibility that these structures are of degenerative nature seems less probable.
    Materialart: Digitale Medien
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  • 92
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 138 (1973), S. 489-502 
    ISSN: 1432-0878
    Schlagwort(e): Chemoreceptor ; Crustacea ; Dendrite ; Cilia ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The innervation of the aesthetasc hairs ofParagrapsus gaimardii differs slightly from that of other decapods described. Each outer flagellum bears from 160 to 170 aesthetascs each of which is innervated by approximately 130 bipolar sensory neurons. Distally the dendrite from each neuron bears two cilia at a ciliary junction. Each ciliary junction lies within an extracellular space and is situated below the base of the aesthetascs. The cilia have a 9+0 structure in their basal region. Just distally this structure becomes disorganized, the A- and B-subfibres separate and the dendrites increase in diameter. There is evidence for the branching of the cilia resulting in approximately 500 sensory endings per aesthetasc. No cellular processes are present in the distal 3/4 of the aesthetasc lumen. No pores were found in the aesthetasc walls which are “spongy” in appearance and permeable to crystal violet along the distal 3/4 of their length. The environmental significance of the “spongy” wall and the possible function of the cilia in early transmission of stimulus energy are discussed.
    Materialart: Digitale Medien
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  • 93
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 138 (1973), S. 523-544 
    ISSN: 1432-0878
    Schlagwort(e): Ovary ; Mink ; Lutein cells ; Plasma progesterone ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of the lutein cells in the mink throughout pregnancy and the regression periodpost partum is described. To correlate the fine structure with the changes in the peripheral plasma progesterone levels, the concentrations of progesterone were measured by a rapid competitive protein-binding assay. Even during the delay period (e.g. as long the plasma progesterone levels remain at the basal level, 〈8ng/ml), the lutein cells in the mink exhibit structural criteria of functional activity. However, the increase in progesterone secretion is accompanied by some morphological transformations, characterized by the presence of more and more small dense homogenous bodies in the cytoplasm, which become irregular and scalloped during the stage with maximum release of progesterone. At this stage the agranular endoplasmic reticulum is often cisternal or vesicular. During the decline of the progesterone levels, typical and moderate electron-dense lipid droplets are found increasingly more within the lutein cells. The expanded agranular ER is now more sparse, while the granular ER becomes more pronounced, often forming parallel arrays. During this phase the mitochondria become elongated, dumb-bell, or cup shaped. After parturition the corpora lutea consist of cells in various stages of degeneration. At day 14post partum only a few lutein cells are still identifiable. Evidently the observed morphological changes take place in the lutein cells during the life span of corpora lutea. This feature lends further support to the concept that the mink lutein cells are steroid-producing cells and furthermore, that the corpora lutea may be the main sites of gestagen production during pregnancy.
    Materialart: Digitale Medien
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  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 140 (1973), S. 445-449 
    ISSN: 1432-0878
    Schlagwort(e): Cecum, Colon ; Mouse ; Glycocalyx ; Intestinal microorganisms ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of the cecal epithelium of the mouse resembles that of more distal parts of the colon. A brief discussion is presented of the possible significance of apical cytoplasmic granules to the glycocalyx and of the close association of microorganisms with the lining epithelium.
    Materialart: Digitale Medien
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  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 140 (1973), S. 459-471 
    ISSN: 1432-0878
    Schlagwort(e): Adenohypophysis ; Sockeye salmon ; Cell types ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of the secretory cells of the adenohypophysis of juvenile sockeye salmon was investigated. Pituitary glands were collected from immature fish transferred experimentally to sea water and subsequently returned to fresh water. The rostral pars distalis contained three cell types: ACTH cells, prolactin cells, and non-secretory cells. The prolactin and non-secretory cells were joined together in the form of follicles by desmosomes and they both had cilia and microvilli projecting into the follicle lumen. Various follicular structures such as lumen, multivesicular structures, and peripheral basement membrane are discussed as possible sites of prolactin cell granule release. The columnar ACTH cells were found at the junction of the rostral pars distalis and the neurohypophysis. The cytoplasmic granules in these cells were characteristically separated from their limiting membrane by a clear space. Multivesicular structures were also found in association with this cell type. The caudal pars distalis also contained three cell types: one acidophil (putative somatotrop) and two basophils (putative thyrotrops and gonadotrops), all of which were similar to those described in adult fish. The pars intermedia contained only one cell type. They appeared to be active cells and were characterized by containing membrane-bounded granules similar to those found in the ACTH cells. Changes in ambient salinity had no apparent effect on any cell type described.
    Materialart: Digitale Medien
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  • 96
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 142 (1973), S. 525-537 
    ISSN: 1432-0878
    Schlagwort(e): Lutein cells ; Guinea pig ; Sexual cycle ; Pregnancy ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Feinstructur der Luteinzellen des Meerschweinchens während Schwangerschaft (15., 35., 45., 50., 55., 63. und 2 Tage nach der Geburt) und Zyklus (9, 14, 16, 20 Tage nach der Ovulation) wurden elektronenmikroskopisch untersucht. In den aktiven Luteinzellen kann man konzentrisch um die Lipoidtropfen angeordnete Strukturen des agranulären endoplasmatischen Retikulum beobachten, die später durch Membranstrukturen des granulären endoplasmatischen Retikulum ersetzt werden. Die Mitochondrien sind rund und enthalten tubuläre Innenstrukturen, die Lipoidtropfen sind elektronenoptisch dicht. Während der Rückbildung des Corpus luteum setzt sich das endoplasmatische Retikulum aus ungeordneten Vesikeln und Tubuli zusammen, die Mitochondrien sind länglich oder verzweigt, die Lipoidtropfen elektronenoptisch hell. Die Bedeutung dieser feinstrukturellen Veränderungen in der Luteinzelle wird diskutiert.
    Notizen: Summary The fine structure of the lutein cells in guinea pigs corpora lutea of pregnancy (15th, 35th, 45th, 50th, 55th, 63th day and 2 days after birth) and during oestrous cycle (9, 14, 16, 20 days after ovulation) is described. During the active phase of the corpus luteum the formation of concentric whorls of agranular endoplasmic reticulum around lipid droplets is observed, but later the granular endoplasmic reticulum increases. In this stadium the mitochondria are round with tubulous cristae and the lipid droplets are increased in density. During the involution of the corpus luteum the endoplasmic reticulum does not form concentric whorls, the mitochondria are elongated, polymorphic, the lipid droplets have lower electron density. These ultrastructural changes in the lutein cells are discussed concerning the role of the cell organelles in the steroid synthesis.
    Materialart: Digitale Medien
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  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 146 (1973), S. 439-451 
    ISSN: 1432-0878
    Schlagwort(e): Sympathetic neurons ; Axon retraction ; Guanethidine ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Vasa deferentia of rats chronically treated with high doses of guanethidine sulphate (30 or 60 mg/Kg/day i.p.) were examined using electron microscopic, fluorescence histochemical and pharmacological techniques. Counts of the axon population in segments of the proximal (urethral) end of the vas deferens showed a reduction to approximately 55% and 35% in the number of axon profiles after treatment for one week with the two dose levels respectively. In the same period only a few cell bodies in the hypogastric ganglion (from which most of the adrenergic innervation of the vas deferens arises) reached the stage of terminal degeneration. Although many axons showed some abnormalities, the number of axons observed in terminal stages of degeneration in treated tissue did not exceed, at any stage examined, the very small numbers observed in control tissue. Organ bath studies showed that the contractile response to transmural stimulation was lost fastest at the distal (epididymal) end of the treated vas deferens. These results have led to the conclusion that, in contrast to the degeneration of adrenergic axons produced by surgery or 6-hydroxydopamine, the sympathectomy produced by guanethidinein vivo involves theretraction of adrenergic axons prior to complete degeneration of the cell bodies.
    Materialart: Digitale Medien
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  • 98
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 146 (1973), S. 501-515 
    ISSN: 1432-0878
    Schlagwort(e): Median eminence (Rat) ; Granular vesicles ; Ultrastructure ; Quantitative evaluation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A quantitative evaluation has been made of the sizes of neuronal granular vesicles (GV) in different (sub-)zones of the rat median eminence. On the basis of the frequency distribution of the mean sizes of the GV in the individual nerve profiles, at least 4 tentative categories of nerve profiles may be distinguished. However, available data do not permit characterization of nerve fibre categories in terms of neurohormone and/or neurotransmitter storage. From dorsal to ventral the palisade zone shows a decrease in mean size of GV; furthermore, the relative number of nerve profiles characterized by small GV (mean size smaller than 112 nm) increases. In contrast, the GV in the zona granulosa, that part of the external zone of the median eminence ventral to the palisade zone, are of relatively large size. Qualitative observations indicate that the zona granulosa may be regarded as an area for both storage and release of biologically active substances.
    Materialart: Digitale Medien
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  • 99
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 137 (1973), S. 513-520 
    ISSN: 1432-0878
    Schlagwort(e): Nucleus infundibularis dorsalis ; Hypothalamus ; Xenopus laevis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of the nucleus infundibularis dorsalis (NID) of the toad Xenopus laevis is described. The nucleus is paired and located in the caudal hypothalamus, dorso-laterally of the caudal end of the paraventricular organ (PVO), and bordering the dorsal wall of the recessus mamillaris. Two cell types can be identified. They are both bipolar and contain dense-core vesicles. Their apical processes protrude into the lumen of the recessus mamillaris, and therefore they are considered liquor-contacting neurons. Because of the Falck-positivity of these cells (Terlou and Ploemacher, 1973) it is assumed that the densecore vesicles contain monoamines. Both cell types probably are sensory cells, although the possibility of their being secretory active as well, cannot be excluded.
    Materialart: Digitale Medien
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  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 139 (1973), S. 201-215 
    ISSN: 1432-0878
    Schlagwort(e): Median eminence ; Mouse ; Ontogenesis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Les fibres nerveuses renfermant des vésicules granuleuses et des vésicules de type synaptique apparaissent dans l'éminence médiane de foetus de 14 jours. Dés le 18è jour foetal, de véritables terminaisons nerveuses sont au contact des capillaires du plexus intercalaire, constituant une charnière neurohémale. Les anses intrainfundibulaires commencent à pénétrer dans l'éminence médiane à la naissance mais ce n'est que chez des souris de 5 jours qu'elles deviennent très nombreuses. — Nous discuterons sur des critères morphologiques, de la possibilité d'un contrôle hypothalamique sur l'adénohypophyse avant la naissance.
    Notizen: Summary Nerve fibers containing granular vesicles and vesicles closely resembling synaptic vesicles appear in the median eminence of 14 days old mouse fetuses. At 18th fetal day true nerve endings have been observed which are located close to the capillaries of the superficial plexus forming a neurovascular link. The capillary loops penetrate into the median eminence at the time of parturition but only in 5 days old mice they can be observed more frequently. — On the basis of the morphological observations presented the question is discussed whether the hypothalamus can influence pituitary hormone secretion before birth.
    Materialart: Digitale Medien
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