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  • Cell & Developmental Biology  (4)
  • onion fly  (4)
  • Electron microscopy  (3)
  • 1
    ISSN: 1432-0533
    Schlagwort(e): Postischemic recirculation ; Complete cerebral ischemia ; Ischemic neuronal injury ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The neuronal response to complete cerebral ischemia (CCI) of 5–15 min duration was evaluated at the light and electron microscopic level subsequent to postischemic recirculation periods of up to 60 min. Following postischemic reperfusion, the homogeneous neuronal changes characteristic of permanent CCI were modified into a heterogeneous pattern of selectively vulnerable neuronal responses. Four basic types of neuronal injury were represented within this heterogeneous neuronal population. The Type I neuronal response was most numerous and consisted of chromatin clumping, nucleolar condensation and a breakdown of polysomes. This response may represent a reversal of some of the neuronal changes observed after permanent CCI. In addition to the above changes, Type II neurons contained swollen mitochondria and Golgi saccules which appeared as microvacuoles under the light microscope. Type III neurons displayed varying degrees of neuronal shrinkage and numerous swollen mitochondria. Type IV neurons were markedly shrunken and electron-dense with few identifiable subcellular structures. The distribution of Type I neurons was random but the other neuronal responses occurred in “selectively vulnerable” brain regions. The number of Type II, III, and IV neurons increased with extended insult durations but were unaffected by the length of recirculation. Ten minutes of CCI represented the threshold for a significant increase in the number of severely altered neurons. These findings suggest that considerable neuronal injury may be present after 10–15 min of CCI, and the lack of a recirculation period following CCI appears to afford the brain parenchyma an extensive degree of structural protection.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 47 (1979), S. 1-11 
    ISSN: 1432-0533
    Schlagwort(e): Experimental Concussion ; Peroxidase, neuronal uptake ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Neuronal inundation with i.v. infused horseradish peroxidase was studied following concussive brain injury by means of both light and electron microscopy. In animals sustaining mechanical brain injury of insufficient intensity as to elicit either microscopic intraparenchymal hemorrhage or other neuropathological change, yet of sufficient intensity as to provoke a physiological concussive response, vascular peroxidase exudation concomitant with neuronal peroxidase inundation occurred throughout the raphe and reticular core. Initially such inundated neurons were totally flooded with the tracer and as such appeared reminiscent of cells visualized in Golgi preparations. However, over the course of a 24-h period these peroxidase flooded neurons apparently organized the peroxidase into vesicles and vacuoles which assumed a perinuclear position from where the peroxidase ultimately reached both the nucleus und nucleolus. It was remarkable that these events occurred without any evidence of subcellular alteration. We interpret such initial inundation with this protein tracer, its ultimate reorganization, and its nuclear and nucleolar uptake as being consistent with some form of subtle and transient neuronal perturbation. We speculate that as such this neuronal perturbation may constitute a morphological correlate of the concussive episode.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 48 (1979), S. 113-125 
    ISSN: 1432-0533
    Schlagwort(e): Complete cerebral ischemia ; Postischemic recirculation ; Electron microscopy ; Nuclear perturbations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Neuronal, astrocytic, and oligodendrocytic elements in several brain loci of the cat were examined at the light and electron microscopic level immediately after periods of complete cerebral ischemia (CCI) uncomplicated by post-ischemic recirculation. Such CCI episodes ranged from 1.5–25 min duration and were methodically produced in a cat model employing rigorous physiological controls. Subsequent to these CCI insults, morphological alterations occurred in a homogeneous manner within each cell type of all loci examined; however, variation in the temporal onset and magnitude of alterations among the various cell types was observed. With brief ischemic insults all cell nuclei demonstrated pronounced nuclear alterations, while their cytoplasmic organelles displayed minimal change. Chromatin clumping and nucleolar condensation were observed in both neurons and glia subsequent to 1.5–5 min of CCI, respectively. With increasing durations of CCI such changes were more dramatic and conspicuous alterations of the cytoplasmic organelles were observed. On the basis of extensive morphological analyses the present study illustrates that nuclear alterations are the first to occur subsequent to CCI. The homogeneity of neuronal involvement seen subsequent to CCI uncomplicated by post-ischemic recirculation is inconsistent with the “selective vulnerability” purported to occur by others. The significance of this inconsistency remains to be assessed; yet, the suggestion is advanced that post-ischemic recirculation may be a factor in the genesis of such vulnerability.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 38 (1985), S. 151-155 
    ISSN: 1570-7458
    Schlagwort(e): Onion maggot ; onion fly ; Delia antiqua ; feeding preference ; Allium cepa ; plant nitrogen ; insect/plant interactions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract When given a choice of feeding sites in laboratory arenas, Delia antiqua (Meigen) larvae exhibited a 3: 1 bias for internal vs outer sections of onion bulbs and distributed themselves non-randomly among identical preferred onion sections. Larval clustering did not appear to be correlated with increased fitness in the laboratory; larval development was identical across the range of densities from 1 to 50 larvae per onion. Larvae feeding on preferred internal sections developed 14% faster, were 38% heavier upon pupation, and were two times more likely to survive to the adult stage than larvae feeding on outer sections. D. antiqua larval food preference was therefore positively correlated with increased fitness.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 43 (1987), S. 279-286 
    ISSN: 1570-7458
    Schlagwort(e): Delia antiqua ; Hylemya ; Anthomyiidae ; onion fly ; antixenosis ; oviposition behaviour ; plant-insect interactions ; resistance ; host-plant stimuli
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé A la lumière d'opinions récentes concernant la découverte des plantes-hôtes par D. antiqua, nous avons examiné les conditions de la ‘résistance’ chez plusieurs lignées de A. cepa les moins attaquées lors d'essais en plein champ aux Pays-Bas, et dont on considérait que la ‘résistance’ était due à une antixénose. Des femelles gravides en présence, au laboratoire, d'un choix de plants de 6 semaines, pondent en moyenne 1,6 à 34,8 oeufs par plant. Les différences entre les pontes correspondent aux tailles des plants. Si l'on tient compte de ces dernières, l'analyse de covariance ne montre pas de différence significative entre les pontes sur les différentes lignées. Des substituts de feuilles ont été créés de façon à faire varier les paramètres de taille tout en maintenant constants les autres stimuli de la plante: pour des plantes, dont le diamètre à la base variait de 1 à 4 mm et la hauteur de 100 à 350 mm, seul le diamètre a significativement influé sur la ponte. Les pontes sur les plantes hors de ces dimensions n'ont pu être expliquées par les seules différences de diamètre. Comme les paysans des principales régions productrices d'oignons d'Europe et des U.S.A. font des bénéfices importants avec la culture d'oignons précoces, ces lignées, sélectionnées par mégarde pour leur développement lent, ne sont probablement pas une bonne source de ‘résistance’ à la mouche de l'oignon. Cependant, ces résultats soulignent la nécessité de tenir autant compte de la taille de la plante que de son chimisme ou de sa texture lors de l'évaluation et de la création de cultivars résistants.
    Notizen: Abstract When gravid onion fly females, Delia antiqua (Meigen) (Diptera: Anthomyiidae) were presented in laboratory choice test with 6-week-old plants of a susceptible cultivar and of onion breeding lines selected for resistance, mean numbers of eggs laid ranged from 34.8 to 1.6 eggs per plant. Differences in ovipositional responses were mirrored by differences in plant size. Analysis of covariance revealed no significant differences in ovipositional responses to breeding lines when differences in size were taken into account. Foliar surrogates were developed so that single size parameters could be varied while holding all other plant stimuli constant. Tests using these surrogates revealed that among plants with basal diameters of 1 to 4 mm and heights of 100 to 350 mm, diameter alone significantly influenced responses of ovipositing females. Ovipositional responses to plants beyond this size range could not be explained strictly by diameter differences. These results underscore the necessity of considering plant size as well as plant chemistry and texture in efforts to evalute and design resistant cultivars.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 10 (1984), S. 1477-1488 
    ISSN: 1573-1561
    Schlagwort(e): Delia antiqua ; onion fly ; Diptera ; Anthomyiidae ; food attractants ; host attractants ; microbial attractants ; Klebsiella pneumoniae ; bacteria ; Allium ; onion ; garlic ; chive
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Of various chopped vegetables tested,Allium spp. high in propyl-containing alkyl sulfides (e.g.,cepa group) caught the most onion flies in trapping tests in the field. Fly catches to chopped onion increased with bait quantity. Attractancy of chopped onion changed dramatically during aging in the field; catch increased over the first few days, peaked at ca. fivefold over fresh material by 3–5 days, and then declined sharply. This age-dependent increase in attraction was not seen for garlic (known to have antimicrobial properties) nor with chopped onion mixed with chopped garlic. These data suggested that attraction of onion flies to onions was strongly influenced by microbial activity associated with decomposing onions. The bacteriumKlebsiella pneumoniae was identified as a major colonizer of onions maximally attractive to onion flies. This increased attraction is not due to the previously reported microbially produced volatiles ethyl acetate and tetramethyl pyrazine.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 11 (1985), S. 435-440 
    ISSN: 1573-1561
    Schlagwort(e): Delia (Hylemya) antiqua ; Diptera ; Anthomyiidae ; onion fly ; onion maggot ; tube trap ; insect attractants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Responses of onion flies,Delia antiqua, to known attractants were measured in the laboratory with a novel tube-trap bioassay. The relative numbers of flies caught in tube traps baited with enzymatic yeast hydrolysate, brewer's yeast, andn-dipropyl disulfide were similar to those obtained previously with cone traps in the field. Changing the shape of the bioassay cage from a cuboid to a cylinder decreased the experimental error obtained from analysis of variance, as did rotating the floor of the circular cage. This bioassay should be useful in evaluating attractants for other insects that orient along the substrate.
    Materialart: Digitale Medien
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  • 8
    ISSN: 0021-9541
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: B-lymphocyte colonies were grown in semi-solid agar from mouse spleen or lymph node cells in the presence of mercaptoethanol with or without added sheep red cells. High levels of colony-forming cells were present in the spleen or normal mice and nu/nu (athymic) mice but colony-forming cells were rare in the thymus and not detected in activated T-lymphocyte populations. Colony-forming cells were θ-negative and most exhibited Fc receptors. Most colony-forming cells had the sedimentation velocity of small lymphocytes, were non-adherent and had a buoyant density similar to B-lymphocytes. Colony-forming cells were radiosensitive (Do 60 rads) and sensitive to cortisone. Colony formation was potentiated by the addition of adherent spleen cells or peritoneal macrophages. It is concluded that most cells forming B-lymphocyte colonies are themselves characterisable as B-lymphocytes.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 8 (1914), S. 415-418 
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 155 (1993), S. 399-407 
    ISSN: 0021-9541
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Regulation of polyamine transport in murine L1210 leukemia cells was characterized in order to better understand its relationship to specific intracellular polyamines and their analogs and to quantitate the sensitivity by which it is controlled. Up-regulation of polyamine uptake was evaluated following a 48-hr treatment with a combination of biosynthetic enzyme inhibitors to deplete intracellular polyamine pools. The latter declined gradually over 48 hr and was accompanied by a steady increase in spermidine (SPD) and spermine (SPM) transport as indicated by rises in Vmax to levels ∼4.5 times higher than control values. Restoration of individual polyamine pools during a 6-hr period following inhibitor treatment revealed that SPD and SPM uptake could not be selectively affected by specific pool changes. The effectiveness of individual polyamines in reversing inhibitor-induced stimulation of uptake was as follows: putrescine 〈 SPD 〈 SPM = the SPM analog, N1, N12-bis(ethyl)spermine (BESPM). In contrast to stimulation of transport, down-regulation by exogenous polyamines or analogs occurred rapidly and in response to subtle increases in intracellular pools. Following a 1-hr exposure to 10 μM BESPM, Vmax values for SPD and SPM fell by 70%, whereas the analog pool increased to only 400-500 pmol/106 cells - about 15-20% of the total polyamine pool (∼2.8 nmol/106 cells). SPM produced nearly identical regulatory effects on transport kinetics. Both BESPM and SPM were even more effective at down-regulating transport that had been previously stimulated four to fivefold by polyamine depletion achieved with enzyme inhibitors. A dose response with BESPM at 48 hr revealed a biphasic effect on uptake whereby concentrations of analog 〈 3 μM produced an increase in SPD and SPM Vmax values, whereas concentrations 3 μM and higher produced a marked suppression of these values. Cells treated with 3 μM BESPM for 2 hr and placed in analog-free medium recovered transport capability in only 3 hr. Thus, whereas stimulation of polyamine transport is a relatively insensitive and slowly responsive process that tends to parallel polyamine depletion, down-regulation of polyamine transport by exogenous polyamines and analogs and its reversal are rapidly responsive events that correlate with relatively small (i.e., 15-20%) changes in intracellular polyamine pools.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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