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  • 1
    Electronic Resource
    Electronic Resource
    Growth and diet dependant structural adaptations of the digestive tract in juvenile grass carp (Ctenopharyngodon idella, Val.) (1977)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 11 (1977), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The morphology of the intestinal epithelium is described and compared with published data. In the gut of this stomachless fish, three zones can be distinguished based on light and electron microscopic observations of absorptive cells: a rostral zone with numerous fat droplets, a second zone with large P.A.S.-positive supranuclear vacuoles and pinocytotic vesicles, and a third zone without these characteristics. In these zones deep invaginations of the cell membrane is a feature of the basal part of the cells. The presence of pinocytotic vesicles in the second zone is considered evidence of the uptake of undigested protein-like substances.Juvenile grass carp from 15 to 335 days, fed on either animal or vegetable food, were measured. The growth rates indicate that animal food stimulates rapid growth. The data also show a vegetable diet causes a slight increase in relative gut length, mainly in the length of the first zone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1977.tb04110.x
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  • 2
    Electronic Resource
    Electronic Resource
    The carp homeobox gene Ovx1 shows early expression during gastrulation and subsequently in the vagal lobe, the facial lobe and the ventral telencephalon (1998)
    Springer
    Development genes and evolution 208 (1998), S. 56-59 
    Details
    ISSN: 1432-041X
    Keywords: Key words Carp ; Ovx ; Neural development ; Facial lobe ; Vagal lobe
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The homeobox gene Carp-Ovx1 shows similarity to vertebrate and invertebrate Ovx genes and to Drosophila unplugged. Its expression pattern was studied by in situ hybridization in carp embryos and juveniles. During segmentation, expression becomes gradually limited to the neural tube. In juveniles up to 9 weeks old, cells in the ventral telencephalon, the facial lobe and the vagal lobe show Ovx1 expression, confining expression to parts with chemosensory projections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050154
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  • 3
    Electronic Resource
    Electronic Resource
    Isolation of carp cDNA clones, representing developmentally-regulated genes, using a subtractive-hybridization strategy (1996)
    Springer
    Development genes and evolution 205 (1996), S. 460-467 
    Details
    ISSN: 1432-041X
    Keywords: Teleost development ; Subtractive hybridization ; Development-related RNAs ; Molecular markers ; In situ hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A subtractive-hybridization technique, combined with differential screenings and subsequent whole mount in situ hybridization (ISH) reactions, was used to isolate novel cDNA clones representing developmentally-regulated genes of carp. Small-scale differential screenings of an oocyte and a segmentation-stage cDNA library using oocyte-specific and segmentation stage-specific enriched probes, yielded 75 positive clones. ISH screening showed that 65% (15) of the oocyte-stage clones and 50% (26) of the segmentation-stage clones were indeed stage-specific. Partial sequence analysis suggests that approximately 65% of the 41 stage-specific clones represent novel genes. In addition, an Otxl clone was isolated. Two novel clones and the Otxl clone are of special interest for developmental studies. The clones represent genes that are locally expressed during embryonic development. The expression patterns of Otxl and one of the novel clones suggest functions in specification of the anterior-posterior axis. The three clones provide molecular markers for the study of gastrulation and the patterning of the a-p axis in teleosts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00377227
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  • 4
    Electronic Resource
    Electronic Resource
    Regional functional differentiation in the gut of the grasscarp, Ctenopharyngodon idella (Val.) (1979)
    Springer
    Histochemistry and cell biology 64 (1979), S. 235-249 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A regional differentiation — reflecting structural differences — of the intestine of larval and juvenile grasscarps can be illustrated by studying the activity of alkaline phosphatase and the uptake of orally administered horseradish peroxidase. Pinocytosis of peroxidase takes place in a welldefined area of about 23% of the length of the gut (segment II). Neither the rostral ±68% (segment I) nor the caudal ±9% (segment III) shows absorption of the enzyme. Alkaline phosphatase activity, mainly localized at the microvilli of the enterocytes is high in the first segment of the gut and low in the second segment. In larvae, the activity decreases sharply at the transition from segment I to segment II. The activity is weak or absent in the caudal third segment. Quantitative histochemical data are confirmed by biochemical analyses. Alkaline phosphatase activity is found all over the mucosal folds of the first segment, with relatively weak activity at the base and at the tip of the folds. This may be related to a renewal of the epithelium. Our results suggest that active absorption of digested food takes place mainly in the rostral first segment, while the uptake of macromolecules by pinocytosis is a function of the second segment. Comparison of the results with information available in literature leads to a rejection of the hypothesis that the uptake of protein macromolecules in Cyprinids is to be attributed to the absence of a stomach and therefore to an inefficient digestion of proteins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00495024
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  • 5
    Electronic Resource
    Electronic Resource
    The distribution of monoamine oxidase and acetylcholinesterase in the brain of Xenopus laevis tadpoles (1973)
    Springer
    Cell & tissue research 140 (1973), S. 261-275 
    Details
    ISSN: 1432-0878
    Keywords: Brain ; Hypothalamo-hypophysial system ; Xenopus laevis, tadpoles ; Monoamine oxidase ; Acetylcholinesterase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of monoamine oxidase (MAO) in the brain of Xenopus laevis tadpoles (stage 52–56) was studied histochemically with a modified Glenner's tryptamine-tetrazolium method. A moderate activity was observed in fibre regions of the striatum and septum (including the medial and lateral forebrain bundles), in the neuropil of the nucleus amygdalae, in the commissura anterior and commissura hippocampi, in the fibre regions of the diencephalon (including the optic chiasma), in the fibre regions of the tectum opticum and the tegmentum of the mesencephalon and in the white substance of the ventral half of the medulla oblongata. A greater MAO activity was found in the neuropil of the entire nucleus praeopticus. In the partes anterior and magnocellularis of this nucleus, MAO positive fibres are present in close contact with the perikarya, indicating a monoaminergic innervation of these neurons. The perikarya themselves did not show MAO activity. In the neurons of the nucleus praeopticus epichiasmaticus, the paraventricular organ (PVO) and nucleus infundibularis dorsalis (NID), only a slight MAO activity has been demonstrated in the perikarya, whereas a strong MAO positivity was found in the intraventricular protrusions and the neuropil. These data indicate the aminergic character of the neurons of these nuclei. From the postoptic fibre region a MAO positive tract was observed towards the developing median eminence and pars intermedia of the hypophysis. The pars nervosa and some cells of the pars distalis also contained MAO. Along the border of the aquaeduct of Silvius and the fourth ventricle, MAO positive liquor-containing neurons are also present. The distribution of acetylcholinesterase (AChE) was investigated in the hypothalamohypophysial region. AChE activity was found in the neuropil of the nucleus praeopticus magnocellularis, in the fibres of the optic chiasma and in the postoptic fibre region. The neurons of the PVO and NID were AChE negative. An AChE positive tract could be traced from the postoptic fibre region to the developing median eminence and pars nervosa. The pars distalis did not show AChE activity. However, in tadpoles reaching the metamorphic climax, ChE activity appeared in certain cells of the pars distalis; this might be related to degenerative phenomena in the acidophilic cells. The absence of AChE activity in the pars intermedia indicates a regulation of MSH release by peptidergic nerves to be unlikely.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306698
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  • 6
    Electronic Resource
    Electronic Resource
    The pig blastocyst: Its ultrastructure and the uptake of protein macromolecules (1984)
    Springer
    Cell & tissue research 235 (1984), S. 347-356 
    Details
    ISSN: 1432-0878
    Keywords: Blastocyst ; Ultrastructure ; Pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Between days 8 and 11 of pregnancy spherical blastocysts from 0.3 to 10 mm in diameter were flushed from the uterine horns of Dutch Landrace pigs. A description of their ultrastructure is given, and the uptake of horseradish peroxidase and ferritin is demonstrated. The ultrastructure of the trophoblast was similar at all ages studied. The trophoblast which has many apical microvilli is able to take up and digest the macromolecules which were offered in the in vitro incubation medium. The hypoblast consists of flattened cells. In blastocysts 2 mm and larger, compact cells bearing microvilli are found below the embryoblast. Cell organelles indicating protein synthesis are found within hypoblast cells of such blastocysts. In the embryoblast, local concentrations of cell organelles are visible, indicating that differentiation has started. After the disappearance of Rauber's layer, which takes place when the blastocyst reaches a diameter of about 2 mm, superficial embryoblast cells develop short microvilli. The cells do not absorb ferritin or peroxidase but are dependent on the trophoblast for their food requirements. All cell layers in the blastocyst contain mitochondria that have characteristics of those found in steroidproducing cells. The significance of the uptake and digestion of macromolecules by trophoblast cells, the synthesis of protein by hypoblast cells and the possible synthesis of steroids is discussed with respect to the relationship between the cell layers of the blastocyst and in the context of conceptomaternal relationships.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217859
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  • 7
    Electronic Resource
    Electronic Resource
    The ultrastructure and renewal of the intestinal epithelium of the juvenile grasscarp, Ctenopharyngodon idella (Val.) (1978)
    Springer
    Cell & tissue research 187 (1978), S. 181-200 
    Details
    ISSN: 1432-0878
    Keywords: Intestine ; Teleost ; Epithelium ; Renewal ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The intestinal absorptive epithelium of starved and fed fish has been studied electron microscopically. After feeding, cells of the proximal segment of the intestine show morphological characteristics of lipid absorption. Absorptive cells in the middle segment contain many pinocytotic vesicles in both fasted and fed specimens. Absorption of protein macromolecules is supposed to be one of the main functions of this part of the gut. In the most caudal part of the intestine, absorptive cells carry relatively few and short microvilli. The proximal and distal segments show structural indications of a function in osmoregulation. The renewal of the epithelium has been studied with light microscopic autoradiography, using tritiated thymidine. The intestinal mucosal fold epithelium represents a cell renewal system. The cells proliferate at the base of the fold and migrate towards the apex in 10–15 days at 20° C. The functional absorptive cells proved to be generally present in the intestinal epithelium, including the proliferative area. Undifferentiated cells have not been identified. The results will be compared with data on absorption of lipid and protein macromolecules in teleostean and mammalian intestines and with descriptions of the cell renewal system in the mammalian intestine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224364
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  • 8
    Electronic Resource
    Electronic Resource
    The development of the stomach in Clarias lazera and the intestinal absorption of protein macromolecules (1981)
    Springer
    Cell & tissue research 215 (1981), S. 397-415 
    Details
    ISSN: 1432-0878
    Keywords: Stomach ; Epithelium ; Teleost ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of the stomach of the teleost, Clarias lazera, during the early posthatching period, is described, and the developing stomach is compared with that of adult Clarias. The stomach develops in two distinct parts: the corpus, which differentiates first, and the pylorus. The corpus contains a mucous surface epithelium, arranged in folds, and a tubular gland system containing only one type of gland cell, to which the secretion of pepsinogen and HCl is attributed. The pyloric region does not contain tubular glands. From the ultrastructure of the gland cells, the 3H-thymidine labeling index, and the onset of acid production (as determined with pH indicators) it is concluded that a functional stomach is present in juveniles with a standard length of ± 11 mm (approximately 12 days after fertilization at 23–24° C). The ultrastructure of the intestinal epithelium has also been studied. The intestine consists of three segments, similar to those described for stomachless teleosts and a number of fish larvae. In larvae as well as in juveniles, the enterocytes of the second segment show pinocytosis of horseradish peroxidase, although in the juveniles the stomach has already developed. This second segment has the same relative length in all studied larvae and juveniles and is also present in adult Clarias. It is therefore concluded that the capacity to absorb protein macromolecules is not specifically related to the absence of a functional stomach in this teleost species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239123
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  • 9
    Electronic Resource
    Electronic Resource
    The effects of osmotic experiments and prolactin on the mucous cells in the skin and the ionocytes in the gills of the teleost Cichlasoma biocellatum (1971)
    Springer
    Cell & tissue research 121 (1971), S. 93-101 
    Details
    ISSN: 1432-0878
    Keywords: Prolactin ; Mucous cells ; Ionocytes ; Cichlasoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Adult Cichlasoma biocellatum were kept in deionized water, 25% sea-water and tap-water. The mucous cells in the epithelium of the gills and the buccal floor were not affected by the osmotic experiments. In animals kept in deionized water the mucous cells in the skin remained unaffected, but the ionocytes (chloride cells) in the gills were strongly stimulated. Keeping the animals in salt water led to a strong regression of the epidermis including the mucous cells, and of the ionocytes. The regression could be counteracted by prolactin injections. The changes in the skin and the ionocytes could be correlated with the activity of the prolactin producing cells in the adenohypophysis. It is suggested that the epidermis and its mucous cells as well as the ionocytes are under prolactin control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00330920
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  • 10
    Electronic Resource
    Electronic Resource
    The cell types in the adenohypophysis of the cichlid fish Cichlasoma biocellatum regan, with special attention to its osmoregulatory role (1971)
    Springer
    Cell & tissue research 118 (1971), S. 113-126 
    Details
    ISSN: 1432-0878
    Keywords: Pituitary ; Teleost ; Prolactin cells ; Osmoregulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the adenohypophysis of Cichlasoma biocellatum, which may be divided into a pro-, meso-, and meta-adenohypophysis, seven cell types can be distinguished. Treatment with deionized- and salt water effects three of these cell types. The rostral acidophils, which were proved to produce prolactin by means of an immunochemical method, are distinctly stimulated in deionized water and markedly inactivated in 25% sea-water. The putative ACTH cells, bordering neurohypophysial branches in the pro-adenohypophysis, are moderately stimulated by both treatments. The presumptive TSH cells, which in control animals appear to be very active, do not show marked changes in deionized water; they are strikingly inactivated, however, in salt water specimens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00331770
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