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  • Ultrastructure  (349)
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  • 1980-1984  (445)
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  • 1
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    Effects of lead pollution on Ammonia parkinsoniana (foraminifera) : ultrastructural and microanalytical approaches (2015)
    PAGEPress
    Details
    Publikationsdatum: 2022-05-26
    Beschreibung: © The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in European Journal of Histochemistry 59 (2015): 2460, doi:10.4081/ejh.2015.2460.
    Beschreibung: The responses of Ammonia parkinsoniana (Foraminifera) exposed to different concentrations of lead (Pb) were evaluated at the cytological level. Foraminifera-bearing sediments were placed in mesocosms that were housed in aquaria each with seawater of a different lead concentration. On the basis of transmission electron microscopy and environmental scanning electron microscopy coupled with energy dispersive spectrometer analyses, it was possible to recognize numerous morphological differences between untreated (i.e., control) and treated (i.e., lead enrichment) specimens. In particular, higher concentrations of this pollutant led to numerical increase of lipid droplets characterized by a more electron-dense core, proliferation of residual bodies, a thickening of the organic lining, mitochondrial degeneration, autophagosome proliferation and the development of inorganic aggregates. All these cytological modifications might be related to the pollutant-induced stress and some of them such as the thickening of organic lining might suggest a potential mechanism of protection adopted by foraminifera.
    Beschreibung: This research was partially supported by the PRIN 2010-2011 Ministero dell’Istruzione, dell’Università e della Ricerca (MIUR) (protocollo 2010RMTLYR) to R.C. and by US NSF grant OCE-1219948 to J.M.B.
    Schlagwort(e): Foraminifera ; Pollution ; Ultrastructure ; Mesocosm
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
    Format: application/pdf
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  • 2
    Digitale Medien
    Digitale Medien
    Pitfall-trap catches of the carabid beetle Pterostichus melanarius, in relation to gut contents and prey densities, in insecticide treated and untreated spring barley (1984)
    Springer
    Entomologia experimentalis et applicata 36 (1984), S. 23-30 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Pterostichus melanarius ; Coleoptera ; Carabidae ; pitfall traps ; insecticides ; prey ; hunger ; activity ; Rhopalosiphum padi ; Fenitrothion ; Sumicidin (Fenvalerate) ; spring barley
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Au cours d'essais à grande échelle, effectués en 1981 et 1982, sur orge de printemps, pour évaleur l'effet des insecticides Fenitrothion et Sumicidine (fenvalerate) sur les arthropodes utiles, un accroissement significatif des captures, dans des trappes pièges de Barber, de Pterostichus melanarius (Illiger) a été observé plusierus semaines après le traitement dans les lots traités par rapport aux lots témoins. Significativement plus de femelles de P. melanarius ont été capturées dans les parcelles traitées pendant cette période d'accroissement après traitement. Une diminution correspondante dans les populations de proies a été observée à la suite des traitements. Chaque femelle de P. melanarius des parcelles traitées avait une fraction significativement moins importance de son intestin remplie d'aliments solides (arthropodes) que celles des parcelles non traitées. Des auteurs précédents avaient observé des taux de capture plus rapides dans les trappes et ne plus grande mobilité des carabes affamés. La réduction des populations proies par l'application d'insecticides affamerait les carabes dont l'activité serait par suite plus élevée. Comme le taux de captures dans les trappes est dû à la fois à la taille de la population et à son activité, on en déduit que la capture par trappes seule ne peut donner une image exacte de l'effet des insecticides sur les populations de carabes dans les champs.
    Notizen: Abstract During large-scale field experiments in 1981 and 1982, designed to assess the effects of the insecticides Fenitrothion and Sumicidin (Fenvalerate) on beneficial arthropods in spring barley, significant increases in pitfall-trap catches of Pterostichus melanarius (Illiger) were observed in treated plots compared to untreated controls, several weeks after treatment. Significantly more female P. melanarius were caught in treated plots during these post-treatment increases. Corresponding decreases were observed in prey populations following treatments. Individual female P. melanarius from treated plots had significantly fewer of their gut areas full of solid (arthropod) food when compared to those from untreated control plots. Earlier workers observed both faster recapture rates in pitfalls and higher mobility in hungry carabid beetles. The following hypothesis is suggested: reducing prey populations by the application of insecticides results in hungrier carabid beetles with consequently higher activity. Since pitfall-trap catch is determined not only by population size but also activity, it is argued that pitfall-trap catches alone cannot give a true measure of the effects of insecticides on carabid populations in the field.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00345200
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  • 3
    Digitale Medien
    Digitale Medien
    Ecdysteroids during pupal development of female Xyleborus ferrugineus (1981)
    Springer
    Entomologia experimentalis et applicata 30 (1981), S. 151-156 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Xyleborus ferrugineus ; pupae ; ecdysteroids ; pharate adult ; radioimmunoassay ; Coleoptera ; Scolytidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Der Ecdysteroidtiter weiblicher Puppen von Xyleborus ferrugineus (Fabr.) wurde geschätzt, indem ganze Tiere homogenisiert und radioimmunologisch untersucht wurden. Ein ausgeprägtes Maximum an Ecdysteroiden wurde bei 36 Stunden Puppenent-wicklung beobachtet (743 pg/mg Körpergewicht). Der Titer nahm ab auf 299 pg/mg im Pharatstadium und auf 193 pg/mg unmittelbar vor Schlüpfen der Adulten. Qualitative Studien mit HPLC ergaben in frischen Puppen ein Verhältnis von 3:1 Ecdyson zu 20-Hydrooxyecdyson. Pharatstadien enthielten vor allem 20-Hydrooxyecdyson. Das beobachtete einzige Maximum im Titer stimmt überein mit den Resultaten bei andern untersuchten Coleopteren.
    Notizen: Abstract Ecdysteroid titers were estimated on the whole body homogenates of Xyleborus ferrugineus (Fabr.) female pupae during development by radioimmunoassay. A distinct peak of ecdysteroids was observed at 36-hr pupal development (743 pg/mg body wt). Titer declined to 299 pg/mg by the pharate adult stage and to 193 pg/mg body wt just before adult emergence. Qualitative studies by HPLC revealed a ratio of 3:1 ecdysone to 20-hydroxyecdysone in the initial pupal stage. Pharate adults had mainly 20-hydroxyecdysone. The observed single peak in ecdysteroid titer agrees with findings in other studied coleopteran species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00300880
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  • 4
    Digitale Medien
    Digitale Medien
    The feeding characteristics and development of larvae of a salvinia weevil Cyrtobagous sp. (1983)
    Springer
    Entomologia experimentalis et applicata 34 (1983), S. 291-296 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Coleoptera ; Curculionidae ; Cyrtobagous ; Salvinia weevil ; Feeding characteristics of larvae ; Development of larvae ; Plant nutrition ; Temperature effects on development
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Après leur naissance, les larves de Cyrtobagous sp. passent de 1 à 4 jours à brouter les racines, et de 0 à 9 jours dans les bourgeons de la plante hôte, Salvinia molesta, avant d'y creuser une galerie dans le rhizome. Bien que les larves aient été capables de survivre jusqu'à 38 jours en broutant les racines, quant elles furent privées de rhizome, elle ne purent achever leur développement. Quand les galeries furent commencées, le développement larvaire, entre 21° et 31°, dépendit de la température et de la teneur en azote de l'hôte. Les larves ne se développèrent pas à 17°. Une haute valeur nutritive de l'aliment consommé par les larves réduisit la durée du développement, mais n'influença pas la durée ultérieure de leur développement nymphal. Les lieux de prise de nourriture et les dégâts produits par des larves isolées furent précisés.
    Notizen: Abstract Newly-emerged larvae of a salvinia weevil, Cyrtobagous sp. spent from 1–4 days browsing on the roots and from 0–9 days in the buds of the host plant, Salvinia molesta, prior to tunnelling into the rhizome of this aquatic weed. Although larvae were able to survive up to 38 days browsing on roots when rhizomes were withheld, they were unable to complete development. After tunnelling began, larval development between 21° and 31° was dependent on temperature and nitrogen levels in the host. Larvae failed to develop at 17°. High nutritional intake by the larvae reduced larval development time but did not influence duration of their subsequent pupal development. The feeding sites and plant damage produced by individual larvae were assessed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00186928
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  • 5
    Digitale Medien
    Digitale Medien
    Distribution of proteinases and carbohydrases in the midgut of larvae of the sweetpotato weevilCylas formicarius elegantulus and response of proteinases to inhibitors from sweet potato (1984)
    Springer
    Entomologia experimentalis et applicata 36 (1984), S. 97-105 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Coleoptera ; Curculionidae ; Cylas formicarius elegantulus ; sweetpotato weevil ; sweet potato ; digestion ; enzyme distribution ; trypsin-inhibitors ; resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé L'activité endoprotéinase était limitée au liquide de la lumière des régions ventriculaires antérieure et postérieure de l'intestin moyen des larves deCylas formicarius elegantulus Summers. Les aminopeptidases ont été trouvées dans le liquide de la lumière (18%), mais étaient principalement associées avec les fractions insolubles des cellules du ventricule postérieur (82%). Suivant le substrat, l'activité carboxypeptidase était à peu près également répartie entre le liquide de la lumière et les fractions insolubles des cellules du ventricule postérieur. L'amylase, enzyme secrétée, a été observée à la fois dans la lumière antérieure et postérieure. Cinq bandes d'activité amylase ont été révélées sur zymogrammes d'amidon après électrophorèse d'intestins moyens entiers. Trois des bandes d'amylase pouvaient provenir de la plante. Il y avait au moins 2 α-glucosidases, une secrétée et une liée aux cellules du ventricule antérieur. L'activite β-glucosidase était liée aux cellules du ventricule antérieur, fandis que l'activité α-galactosidase était limitée au fluide de la lumière. Les activités β-galactosidase et cellulase ont été trouvées à la fois dans le liquide de la lumière et dans la fraction cellulaire insoluble. Ainsi, la digestion initiale des grosses protéines et des polymères de carbohydrates se produit dans le liquide de la lumière dans les régions ventriculaires antérieure et postérieure. Cependant, l'achèvement de la digestion des oligopeptides se produit principalement dans le ventricule postérieur, tandis que la fin de la digestion des oligosaccharides se produit dans le ventricule antérieur. Les concentrations en inhibiteurs de trypsine de 5 cultivars d'I. batatas L. diffèrent de 1 à 20. Les endoprotéinases deC. formicarius elegantulus ont été inhibées par des extraits de cultivars, mais les cultivars avec des concentrations relativement élevées d'inhibiteur avainent antérieurement montré être susceptibles d'être attaqués par le coléoptère dans des essais en champs.
    Notizen: Abstract Endoproteinase activity was confined to luminal fluid from anterior and posterior ventricular regions of midguts of larvae of the sweetpotato weevil,Cylas formicarius elegantulus (Summers). Aminopeptidase was found in luminal fluid (18%) but was primarily associated with insoluble fractions from cells of the posterior ventriculus (82%). Depending on substrate, carboxypeptidase activity was about equally distributed between luminal fluid and insoluble fractions from posterior ventriculus cells. Amylase was found in luminal fluid in both the anterior and posterior ventriculus. Five bands of amylase activity were detected on starch zymograms following electrophoresis of whole midgut samples. Three of the amylase bands may be plant-derived. At least two α-glucosidases were present, one secreted and one bound to anterior ventriculus cells. β-Glucosidase activity was bound to anterior ventriculus cells whereas α-galactosidase activity was confined to luminal fluid. β-Galactosidase and cellulase activities were found in both luminal fluid and the insoluble cell fraction. Thus, initial digestion of large protein and carbohydrate polymers occurs in luminal fluid in both anterior and posterior ventriculus regions. However, terminal digestion of oligopeptides occurs primarily in the posterior ventriculus while terminal digestion of oligosaccharides occurs in the anterior ventriculus. A 20-fold difference in trypsin-inhibitor concentration was found among five sweetpotato cultivars. Endoproteinases from sweetpotato weevil larvae were inhibited by extracts from the cultivars but cultivars with relatively high concentrations of inhibitor were previously shown to be susceptible to weevil attack in field trials.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00569949
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  • 6
    Digitale Medien
    Digitale Medien
    A new, X-linked body colour mutation in Tribolium confusum (1983)
    Springer
    Entomologia experimentalis et applicata 34 (1983), S. 124-126 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Negret ; Melanic mutant ; X-linked mutation ; Flour Beetle ; Tribolium confusum ; Coleoptera
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00300913
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  • 7
    Digitale Medien
    Digitale Medien
    Responses of Prostephanus truncatus to components of the aggregation pheromone of Rhyzopertha dominica in the laboratory and field (1983)
    Springer
    Entomologia experimentalis et applicata 34 (1983), S. 266-272 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Storage pests ; Coleoptera ; Bostrichidae ; Prostephanus truncatus ; (±)-1-methylbutyl (E)-2-methyl-2-pentenoate ; Rhyzopertha dominica ; (±)-1-methyl-butyl (E)-2,4-dimethyl-2-pentenoate ; Dominicalure ; Aggregation pheromone ; Monitoring
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Les réponses de Prostephanus truncatus Horn (Coleoptera: Bostrichidae) à deux constituants de la phéromone d'agrégation de Rhyzopertha dominica Fabricius (Coleoptera: Bostrichidae), le (±)-1-méthylbutyl (E)-2-méthyl-2-penténoate et le (±)-1-méthylbutyl (E)-2,4-diméthyl-2-pentéoate, connus comme “Dominicalure 1” et “Dominicalure 2”, ont été étudiées au laboratoire et au champ. Auslaboratoire ces composés ont été essayés individuellement et en mélange 1:2. Une membrane de caoutchouc imprégnée de phéromone a été utilisée comme émetteur lent, et une courbe de réponse en fonction de la dose a été établie. P. truncatus répondait plus vigoureusement à la Dominicalure 2 seule. Tous ces traitements ont été comparés dans un essai aux champs en Tanzanie, dans lesquels des pièges en carton ondulé contenant des diffuseurs de phéromone étaient placés dans des entrepôts de maïs dans les fermes. La Dominicalure 1 et le mélange de 1 et 2 étaient tous deux efficaces pour piéger R. dominica. La Dominicalure 2 a piégé plus de P. truncatus que les autres traitements et était à peu près aussi efficace que le contrôle visuel pour détecter la présence de cet insecte dans les stocks. On peut envisager que la Dominicalure 2 pourrait servir de base à un programme pour lutter contre P. truncatus en Afrique de l'Est.
    Notizen: Abstract Laboratory and field studies have been made of the responses of Prostephanus truncatus (Horn) to two components of the aggregation pheromone of Rhyzopertha dominica (Fabricius) — (±)-1-methylbutyl (E)-2-methyl-2-pentenoate and (±)-1-methylbutyl (E)-2,4-dimethyl-2-pentenoate, known as “Dominicalure 1” and “Dominicalure 2” respectively. In the laboratory, these compounds were tested individually and as a 1:2 mixture; P. truncatus responded most strongly to Dominicalure 2 alone. All three treatments were compared in a field trial in Tanzania to monitor both R. dominica and P. truncatus in farm stores. Dominicalure 1 or a mixture of 1 and 2 were both highly effective for trapping R. dominica. In contrast, Dominicalure 2 trapped more P. truncatus than the other treatments and was about as effective as visual inspection at demonstrating the presence of the beetle in stores. Dominicalure 2 could form the basis of a monitoring programme for P. truncatus in East Africa.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00186923
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  • 8
    Digitale Medien
    Digitale Medien
    Ultrastructure of differentiating preameloblasts from tooth germs of the permanent dentition ofMacaca mulatta andMacaca arctoides (1981)
    Springer
    Calcified tissue international 33 (1981), S. 603-618 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Preameloblasts ; Tooth germs ; Monkey ; Enamel ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Cytodifferentiation of inner enamel epithelium and the adjacent connective tissue from the tip of the cervical loop to the initiation of enamel elaboration in twoMacaca species was examined. Ten- to twelve-month-old specimens were fixed by perfusion and the permanent tooth buds were prepared for transmission electron microscopy. At the cervical loop proper, inner enamel epithelium cells have lobed nuclei, a paucity of cytoplasm, and wide extracellular spaces; the basal lamina facing the dental papilla is straight. With increasing distance from the tip of the cervical loop, the following changes occur gradually: (a) preameloblasts elongate from 15 to 45 µm, and their organelles, particularly mitochondria and profiles of rough endoplasmic reticulum, become more numerous; (b) extracellular spaces decrease between preameloblasts starting at the basal (infranuclear) end; (c) the basement membrane becomes convoluted and associated with aperiodic fibers; (d) preodontoblast projections penetrate the aperiodic fibers; (e) collagen fibers subjacent to the basement membrane increase in density, with particularly thick fibers paralleling the aperiodic fibers. These modifications occur within three-fourths of the distance from the tip of the cervical loop to the mineralization front. The condensation of preodontoblasts is followed immediately by predentin synthesis. Concomitantly, the basement membrane breaks down and the aperiodic fibers are engulfed by preameloblasts. Preameloblast projections penetrate junctional predentin, contact mineralized dentin, and enamel synthesis ensues. At this stage the ameloblast is 45 µm long, the nucleus is central or basal, the Golgi apparatus has migrated apically, but the Tomes' process has not yet formed. The results indicate that odontogenesis inMacaca monkeys more closely resembles human odontogenesis than does that in the murine rodents.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02409498
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  • 9
    Digitale Medien
    Digitale Medien
    Ultrastructural localization of adenylate cyclase and cAMP phosphodiesterase in the gastrulating chick embryo (1983)
    Springer
    Development genes and evolution 192 (1983), S. 42-44 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Chick embryo ; Gastrulation ; Adenylate cyclase ; cAMP phosphodiesterase ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ultrastructural localization of adenylate cyclase (E.C. 4.6.1.1.) and cAMP phosphodiesterase (PDE) (E.C. 3.1.4.17.) in the ectoderm of the developmental stage 4 chick embryo was studied. Adenylate cyclase was localized in the lateral surfaces of the ectodermal cells. In the primitive streak cells the enzymatic activity was observed on all the lateral surfaces, whereas in the periphery of the blastoderm the reaction product was localized in the apical parts of the lateral plasma membranes only. cAMP PDE localized in the apical cytoplasm of the ectodermal cells, with highest activity in the globular projections.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00848768
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  • 10
    Digitale Medien
    Digitale Medien
    Electron microscopical study of self-differentiation potency in the chick embryonic endoderm cultured in vitro (1983)
    Springer
    Development genes and evolution 192 (1983), S. 171-178 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Differentiation ; Digestive tract ; Endoderm ; Organ culture ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The self-differentiation potency of the endoderm of the chick embryo was investigated mainly by transmission electron microscopy. Endodermal fragments isolated from 4- to 6-day stomach or small intestine were cultured in the absence of mesenchyme and were able to differentiate in vitro into organ-specific epithelia. Endodermal fragments isolated from the stomach region differentiated into a pseudo-stratified epithelium with periodic acid Schiff-positive mucous granules in the apical cytoplasm, while those from the small intestinal region differentiated into a simple columnar epithelium with a striated border which was positive in alkaline phosphatase activity. These features are comparable with those of the mucous secretory epithelium of the normal embryonic stomach and the absorptive epithelium of normal embryonic small intestine, respectively. Next, the self-differentiation potencies were investigated of the upper and lower layers of the blastoderms, at stages 1–5 of Hamburger and Hamilton (H. and H.). Both stomach-type and small-intestine-type epithelia developed only when fragments of the lower layer isolated from the blastoderms older than stage 3 of H. and H. were cultured, suggesting that cells possessing the potency to differentiate into the stomach- and small-intestine-type epithelia exist in the definitive endoderm at the beginning of its formation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00848687
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  • 11
    Digitale Medien
    Digitale Medien
    Migration and division of cleavage nuclei in the gall midge,Wachtliella persicariae (1980)
    Springer
    Development genes and evolution 188 (1980), S. 65-73 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Nuclear migration ; Cleavage ; Microtubules ; Ultrastructure ; Gall midge
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary In the eggs ofWachtliella persicariae the cleavage nuclei move relative to the surrounding ooplasm. This ‘active’ migration is caused by an organelle whose ultrastructure was studied throughout the mitotic cycle. It consists of a greatly enlarged polar cytaster derived from the mitotic apparatus, linked to the nucleus by 100 Å filaments. The microtubules of the cytaster were found only during periods of active nuclear migration, i.e., from the onset of anaphase to the early prophase of the next mitotic cycle. They are always solitary and follow the course of the astral rays, which are known to temporarily adhere to peripheral structures of the egg cell and to exert tractive forces. In contrast to the cytaster microtubules, the microtubules in the spindle are bundled and persist from early metaphase through late telophase. During ontogenesis the first migration cytaster is built up between 3 and 12 min after oviposition near the anterior egg pole, in the vicinity of the sperm nucleus. In non-inseminated eggs time lapse films show a migration cytaster to develop autonomously in a region free from nuclei, but it does not follow the normal path of the male pronucleus. In several cases the female pronucleus, which remains without a cytaster of its own, was observed to move to the cytaster generated in the absence of the male pronucleus. Whether or not it is adhering to a nucleus, the cytaster divides into two at the correct time, i.e, corresponding to the first cleavage division in fertilized eggs. In some non-inseminated eggs this type of ‘pseudocleavage’ has been observed to occur repeatedly, giving rise to an increasing number of anucleate cytasters.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00848611
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  • 12
    Digitale Medien
    Digitale Medien
    Morphogenesis in the embryo ofDrosophila melanogaster — Germ band extension (1980)
    Springer
    Development genes and evolution 188 (1980), S. 163-177 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Yolk sac ; Ultrastructure ; Embryogenesis ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Changes at the ultrastructural level during germ band extension in the embryo ofDrosophila melanogaster are described. Cytoplasmic connections between cells and the yolk sac are present during initial cellular movements. At this time, a continuous system of microfilaments is present adjacent to the membranes in the connections and at the periphery of the yolk sac. As germ band extension progresses, this system becomes discontinuous, and microfilaments are apparent only in the immediate vicinity of the connections. Cytoplasmic connections are disassembled at approximately the midpoint of extension; at the same time, extensive membrane associations develop between germ band cells and between these cells and adjacent yolk sac membranes. Positioning and orientation of cytoplasmic connections suggest that the yolk sac, via these connections, is actively involved in the cellular movements of early germ band extension.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00849045
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  • 13
    Digitale Medien
    Digitale Medien
    Ultrastructural localization and gradient of activity of alkaline phosphatase activity during rodent odontogenesis (1982)
    Springer
    Calcified tissue international 34 (1982), S. 273-279 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Odontogenesis ; Ultrastructure ; Alkaline phosphatase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The ultrastructural localization and gradient of activity of alkaline phosphatase were studied with respect to cell differentiation, matrix synthesis, and matrix mineralization in the incisor and molar teeth of 4-day-old Sprague-Dawley rats. The animals were perfused intracardially at room temperature with 2.5% glutaraldehyde in 0.1M sodium cacodylate (pH 7.4) with 3–4% sucrose. The jaws were dissected, immersion-fixed for 24 h, and the incisor and molar tooth germs removed. These were demineralized in 10% EDTA in NaOH (pH 7.4) with 7% sucrose. After reactivation of the enzyme with 0.1M MgCl in Tris-maleate buffer (pH 7.4) at 4°C, the teeth were incubated for alkaline phosphatase in a medium consisting of 6 ml 3% sodiumβ-glycerophosphate, 4 ml 0.2M Tris-HCl buffer (pH 9.2), 3 ml 1.6% MgSO4, 12 ml 0.5% lead citrate (pH⋍12), and 2.1 g sucrose. The pH was adjusted to 9.2 with 0.2M HCl, the volume made up to 30 ml, and the solution centrifuged for 10 min at 5000 rpm. Control teeth were incubated in medium minus the substrate. Finally, the specimens were routinely post-fixed and embedded for sectioning and examination with a Philips 300 electron microscope. A gradient of alkaline phosphatase activity was mapped along the developing teeth in the cells of the stratum intermedium, the proximal borders of the ameloblasts, the early dentine matrix, the predentine-dentine border, matrix vesicles, and the plasma membranes of odontoblasts and subodontoblast cells. The gradient of alkaline phosphatase activity was evident in the forming tooth from the cervical loop to the crown apex and was related to the cellular events, matrix synthesis, and matrix mineralization occurring during odontogenesis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02411250
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  • 14
    Digitale Medien
    Digitale Medien
    Ultrastructural study of apatites in human urinary calculi (1980)
    Springer
    Calcified tissue international 31 (1980), S. 93-108 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Calculus ; Ultrastructure ; Apatite ; Transmission ; Scanning
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Using transmission and scanning electron microscopy, we have studied the ultrastructure of a number of urinary calculi, mainly composed of calcium phosphate. Three fundamental kinds of calcium phosphates were detected: nonstoichiometric carbonate apatite, nonhexagonal octacalcium phosphate, and calcium-magnesium whitlockite. The influence that the organic matter, substitutions in the phosphate lattice of CO3 and Mg, and apatitic stoichiometry have on the ultrastructure of the calcium phosphate calculi has been detailed. An originating apatitic unity named U2 is assumed to be the responsible for all the different structures of calcium apatites appearing in renal calculi. On the basis of our observations, a mechanism whereby apatites grow is postulated; magnesium functions as an inhibitor for the growing mechanism.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02407170
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  • 15
    Digitale Medien
    Digitale Medien
    Ultrastructural localization of calcium in the mandibular condylar growth cartilage of the rat (1980)
    Springer
    Calcified tissue international 30 (1980), S. 27-34 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Ultrastructure ; Calcium ; Cartilage ; Vesicles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The potassium pyroantimonate technique was utilized for the selective subcellular localization of calcium in the mandibular condylar cartilage of 1-day-old rats. Electron dense calcium pyroantimonate precipitates were localized principally in mitochondria and at the cell membrane of the chondrocytes. In addition, small intracellular vesicles 0.1–0.2µm in diameter were observed in proximity to the cell membrane of chondrocytes of the mid-hypertrophic zone. The results suggest that these vesicles were being extruded from the cell into the extracellular matrix. Energy-dispersive analysis by X-rays confirmed that calcium is the principal cation of the electron-dense precipitates.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02408603
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  • 16
    Digitale Medien
    Digitale Medien
    Length and shape of enamel crystals (1984)
    Springer
    Calcified tissue international 36 (1984), S. 550-555 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Enamel crystals ; Length ; Shape ; Apatite ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary An original method for fractionating and preparing isolated crystals of homogeneous size was developed. It was demonstrated that enamel apatite crystals are at least 100 µm long. The flexibility of the very long crystallites was demonstrated. Crystal curvatures, accounting for the irregular course of the prisms through the enamel thickness, were visualized and measured. It was shown that in the deep forming enamel layer, lateral branches may grow out of the crystals and crystal fusing often occurs, inducing the crystallites to assume pyramidal shapes with their wide bases pointing toward the dentino-enamel junction and one or two tops toward Tomes' processes. During the maturation process, the two tops of the still immature crystals also fuse so that the mature crystals acquire a rodlike aspect, with parallel faces and steplike graduations along thec axis, allowing a close contact between the crystals. These results support the hypothesis that the crystallites would be continuous from the dentino-enamel junction to the surface.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02405364
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  • 17
    Digitale Medien
    Digitale Medien
    Electron microscopy of avian osteopetrosis induced by retrovirus MAV.2-O (1982)
    Springer
    Calcified tissue international 34 (1982), S. 382-390 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Avian osteopetrosis ; Avian oncornavirus ; Ultrastructure ; Calcification ; Bone cells
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Diaphyseal tibial bone of 12.5 – 13-day and 19-day-old embryos and 20-day-old hatched chicks infected with retrovirus MAV.2-O were examined by transmission electron microscopy. The viruses were associated with lining osteoblasts and osteocytes. Whereas the infection of the osteoblast layer seemed to be a transient stage, virus association with osteocytes was a constant and main ultrastructural feature. The viruses were found either in the osteoid or in the periosteocytic space of the bone lacunae. They arose from dense cytoplasmic areas located near the cell plasmalemma via a budding process. The newly budded virus particles often had a large tail or a fine stalk-like process lost in the extracellular space. The viruses underwent calcification by deposition of inorganic material and were incorporated in the bone trabeculae. No production of virus was observed in typical osteoclasts with well-differentiated ruffled borders. The viral-induced avian osteopetrosis seemed to result from increased bone deposition through stimulation of osteoblast and osteocyte activities, whereas osteoclastic bone resorption seemed to be undisturbed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02411272
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  • 18
    Digitale Medien
    Digitale Medien
    An electron microscopic study on the mating tube formation in the heterobasidiomycete Tremella mesenterica (1980)
    Springer
    Archives of microbiology 128 (1980), S. 215-221 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Mating tube ; Microtubule ; Tremella ; Ultrastructure ; Yeast
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Ultrastructure of the mating tube formed in yeast haplont of the heterobasidiomycete Tremella mesenterica was studied by electron microscopy. Cell wall of the mating tube emerged as evagination of the inner layers, rupturing outer layers of the mother cell wall. Comparison with budding cells suggested that the tube emergence place at bud scar and the process of tube emergence was the same as that of bud emergence. Electron transparent vesicles of 0.1 μm diameter were scattered in the cytoplasm of the mating tube. Nucleus-associated organelle was located at one side of the nuclear envelope which extended towards the mating tube. A few microtubules were detected in the mating tube, but their association with a nucleus was not clear. The cytoplasmic structure of the mating tube was discussed in comparison with that of hyphae of the filamentous fungi.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00406161
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  • 19
    Digitale Medien
    Digitale Medien
    Ultrastructural events and kinetics of microcyst germination in the myxomycete Didymium iridis (1981)
    Springer
    Archives of microbiology 128 (1981), S. 384-389 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Didymium iridis ; Microcyst ; Excystment ; Germination ; Ultrastructure ; Mycetozoa ; Myxomycetes ; Myxamoeba
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Microcysts of the myxomycete Didymium iridis were induced to excyst by transfer to 5mM potassium phosphate buffer. After 1 h in suspension, 90% of the microcysts had germinated into myxamoebae distinguishable by phase contrast microscopy and staining with Lugol's iodine. Both pH and osmolarity affected the kinetics of excystment. The rate and extent of excystment were decreased by cycloheximide but remained unaffected by actinomycin D, suggesting a requirement for protein synthesis but not RNA synthesis. Initially, the outer wall layers separated from the inner layer, which gradually expanded and loosened. The protoplast rehydrated and reverted to a vegetative morphology. Excysting cells were characterized by nucleolar inclusions, changes in the nuclear envelope and plasma membrane, appearance of ringed cisternal elements and microbodies in the cytoplasm, and formation of a densely fibrous zone adjacent to the site of emergence. Excysting populations have been classified into characteristic stages: mature, initiated, swollen, and pre-emergent microcysts.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00405917
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  • 20
    Digitale Medien
    Digitale Medien
    Ultrastructure of the cyanobacterium,Mastigocladus laminosus (1982)
    Springer
    Archives of microbiology 133 (1982), S. 11-19 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Cyanobacteria ; Ultrastructure ; Mastigocladus laminosus ; Fischerella ; True branching
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The morphology and ultrastructure of the thermophilic cyanobacteriumMastigocladus laminosus were examined by scanning and transmission electron microscopy. Mature cultures consisted of relatively old, wide filaments that branched frequently to form younger, thinner filaments. The cells of the younger filaments had a consistently cylindrical morphology, while those of older filaments were rounded and pleomorphic. The internal ultrastructure of the cells depended somewhat on their age. As young cells became larger and wider, their thylakoids underwent slight rearrangement and spread out toward the center of the cytoplasm. Polyphosphate bodies, carboxysomes (polyhedral bodies), and lipid-body-like structures increased in number as the cells aged, but ribosomes and cyanophycin granules were depleted. Cell division involved septum formation followed by ingrowth of the outer membrane and sheath. Cells in older filaments were separated from each other by a complete layer of sheath material. Septum formation in older cells was also seen to occur parallel to the long axis of the filament, thereby confirming that true branching took place.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00943762
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  • 21
    Digitale Medien
    Digitale Medien
    Isolation and characterization of a new coccoid methanogen, Methanogenium tatii spec. nov. from a solfataric field on Mount Tatio (1984)
    Springer
    Archives of microbiology 137 (1984), S. 308-315 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Methanogenium tatii ; Ultrastructure ; Physiology ; Glycoproteins ; DNA-DNA Homology ; Taxonomy ; Archaebacteria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A new coccoid methanogen, Methanogenium tatii, was isolated and characterized. The mesophilic isolate can grow on and produce methane from H2:CO2 and formate. For growth acetate is strictly required. The cell shape, the G+C content of 54 mol% and DNA-DNA homology data suggest it to be a Methanogenium species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00410727
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  • 22
    Digitale Medien
    Digitale Medien
    Fine structure of the knobby spore type of Streptomyces torulosus (1984)
    Springer
    Archives of microbiology 138 (1984), S. 229-232 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Actinomycetes ; Streptomyces torulosus ; Morphology ; Ultrastructure ; Verrucate spores ; Knobby ornamentation ; Sheath
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The type strain of Streptomyces torulosus Lyons and Pridham (1971) was studied by scanning- and transmission electron microscope. Spore chains were formed in spirals by aerial mycelium. The spores were connected by nozzles in which small channels could be observed. The knobby ornamentations of the spores arised on a thin fibrous sheath, enveloping the spore chains. These irregular blunt projections, called knobs, had varying diameters of 100 to 250 nm. The base of the knob, consisting of globose to flattened electron dense material, was sitting directly on the sheath. It was covered by several small vesicles of the same material. Each hollow vesicle beared a thin bowlshaped shell of electron transparent material. In general, the cupular bowls and their supporting vesicles became easily depressed on their base, but not detached from the surface of the spores. This type of knobby spore ornamentation was suggested to be designated as a verrucate spore type.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00402126
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  • 23
    Digitale Medien
    Digitale Medien
    The effects of nitrogen limitation on the ultrastructure of the cyanobacterium Agmenellum quadruplicatum (1981)
    Springer
    Archives of microbiology 130 (1981), S. 204-212 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Agmenellum quadruplicatum ; Nitrogen starvation ; Ultrastructure ; PATO poststain ; Cyanobacteria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effects of nitrogen limitation on the ultrastructure of the unicellular cyanobacterium, Agmenellum quadruplicatum, were studied by thin sectioning transmission electron microscopy. Nitrogen became limiting for growth 14–15 h after transfer to nitrogen-limiting medium, but cultures retained full viability for at least 45 h. The c-phycocyanin: chlorophyll a ratio and cellular nitrogen content of the culture dropped rapidly after 14–15 h, as a progressive deterioration of major cell structures took place. Phycobilisomes were degraded first, followed by ribosomes and, then, thylakoid membranes. These structures were virtually depleted from the cells within 26 h. Intracellular polysaccharide accumulated in place of the normal cell structures throughout this period. Nitrogen limitation did not affect polyphosphate bodies, carboxysomes, lipid granules, the cell envelope, or the extra-cellular glycocalyx. All of the ultrastructural changes resulting from nitrogen limitation were reversed upon addition of nitrate to a starved culture. Most cell structures were restored within 3 h, and restoration was complete within 9 h.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00459520
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  • 24
    Digitale Medien
    Digitale Medien
    Arthrobacter P 1, a fast growing versatile methylotroph with amine oxidase as a key enzyme in the metabolism of methylated amines (1981)
    Springer
    Archives of microbiology 129 (1981), S. 72-80 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Arthrobacter ; Facultative methylotroph ; Amine oxidase ; Catalase ; RuMP cycle of formaldehyde fixation ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A facultative methylotrophic bacterium was isolated from enrichment cultures containing methylamine as the sole carbon source. It was tentatively identified as an Arthrobacter species. Extracts of cells grown on methylamine or ethylamine contained high levels of amine oxidase (E.C. 1.4.3.) activity. Glucose- or choline-grown cells lacked this enzyme. Oxidation of primary amines by the enzyme resulted in the formation of H2O2; as a consequence high levels of catalase were present in methylamine-and ethylamine-grown cells. The significance of catalase in vivo was demonstrated by addition of 20 mM aminotriazole (a catalase inhibitor) to exponentially growing cells. This completely blocked growth on methylamine whereas growth on glucose was hardly affected. Cytochemical studies showed that methylamine-dependent H2O2 production mainly occurred on invaginations of the cytoplasmic membrane. Assimilation of formaldehyde which is generated during methylamine oxidation was by the FBP variant of the RuMP cycle of formaldehyde fixation. The absence of NAD-dependent formaldehyde and formate dehydrogenases indicated the operation of a non-linear oxidation sequence for formal-dehyde via hexulose phosphate synthase. Enzyme profiles of the organism grown on various substrates suggested that the synthesis of amine oxidase, catalase and the enzymes of the RuMP cycle is not under coordinate control.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00417184
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  • 25
    Digitale Medien
    Digitale Medien
    Changes of the cytoplasmic ultrastructure during development of sclerotia in Claviceps purpurea (Fr.) Tul. (1980)
    Springer
    Archives of microbiology 125 (1980), S. 251-257 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Claviceps purpurea ; Ultrastructure ; Development ; Sclerotium ; Oleosomes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The development of sclerotia of Claviceps purpurea was investigated by light and electron microscopy. During the first days after infection sterigma and conidiospores are formed. The spores show a moderately developed vacuolar system, they are thick walled and contain about 20% lipid (related to the cell volume) embedded in glycogen. The sterigma are cylindrical unicellular hyphae with electron dense cytoplasm and isolated strongly contrasted lipid droplets. In maturing sclerotia the hyphae become septated with increasingly thick cell walls and a large lipid content. The lipid forms small droplets in young cells, while in the mature sclerotium it occurs in the form of very large drops, occupying the major part of the cell. Simultaneously the composition of the lipid is changed. The mature cells have several nuclei. They are partially connected by osmiophilic substances, forming a network of intercellular spaces.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00446885
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  • 26
    Digitale Medien
    Digitale Medien
    Membrane-bound nitrite oxidoreductase of Nitrobacter: evidence for a nitrate reductase system (1984)
    Springer
    Archives of microbiology 140 (1984), S. 153-158 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Nitrobacter hamburgensis ; Nitrite oxidoreductase ; Nitrate reductase ; Molybdenum iron-sulfur protein ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Nitrite oxidoreductase, the essential enzyme complex of nitrite oxidizing membranes, was isolated from cells of the nitrifying bacterium Nitrobacter hamburgensis. The enzyme system was solubilized and purified in the presence of 0.25% sodium deoxycholate. Nitrite oxidoreductase oxidized nitrite to nitrate in the presence of ferricyanide. The pH optimum was 8.0, and the apparent K m value for nitrite amounted to 3.6 mM. With reduced methyl-and benzylviologen nitrite oxidoreductase exhibited nitrate reductase activity with an apparent K m value of 0.9 mM for nitrate. NADH was also a suitable electron donor for nitrate reduction. The pH optimum was 7.0. Treatment with SDS resulted in the dissociation into 3 subunits of 116,000, 65,000 and 32,000. The enzyme complex contained iron, molydbenum, sulfur and copper. A c-type cytochrome was present. Isolated nitrite oxidoreductase is a particle of 95±30 Å in diameter.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00454918
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  • 27
    Digitale Medien
    Digitale Medien
    Ultrastructure of tuberculate spores in Streptomyces thermoviolaceus (1983)
    Springer
    Archives of microbiology 134 (1983), S. 295-298 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Actinomycetes ; Streptomyces thermoviolaceus ; Sporogenesis ; Spore ornamentation ; Cupular knobs ; Sheath ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The sporogenesis of aerial spores in Streptomyces thermoviolaceus corresponded to a common sporulation type in the genus. The sporulation septum was composed of an outer ring-shaped constriction wall and an inner interspace septum arising by the inwards growth of a double annulus. In mature spores the wall was composed of two layers, the outer one was part of the parent hyphal wall and septum material, the inner one was formed de novo. The spore chains were enclosed by the thin breakable sheath containing small rod-like elements. The ornamentation in the form of knobs, which were a characteristic feature of the species originated from the sheath. The knobs were hemispherical particles with an inner electron dense core and an outer electron transparent shell. The term “cupular knobs” was suggested for this type of tuberculate ornamentation. Frequently, the knobs became detached from the surface in which case the inner core separated easily from the shell.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00407805
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  • 28
    Digitale Medien
    Digitale Medien
    Chroococcus S24 and Chroococcus N41 (cyanobacteria): morphological, biochemical and genetic characterization and effects of water stress on ultrastructure (1983)
    Springer
    Archives of microbiology 135 (1983), S. 81-90 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Cyanobacteria ; Ultrastructure ; Nitrogen fixation ; Water stress ; Taxonomy ; DNA ; Plasmids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Two strains of desiccation-tolerant coccoid cyanobacteria, Chroococcus S24, a marine form, and Chroococcus N41, a cryptoendolith isolated from a hot-desert rock, have been characterized. The mol % DNA base compositions of the strains are 47.1 and 48.9% respectively. Plasmid DNA was not detected in either strain. The pigment contents and nutritional characteristics of the strains are identical. Both lack phycoerythrinoid pigments and, in culture, behave as slow-growing halotolerant marine forms with elevated requirements for Na+, Cl−, Mg2+ and Ca2+. Sucrose was the only carbon source of those tested that supported photoheterotrophic growth. Each strain synthesizes nitrogenase under anaerobic conditions but not in air. Morphologically the two strains are indistinguishable. They are considered to be independent isolates of the same cyanobacterial species. Chroococcus N41 was studied in detail with the electron microscope. When brought to equilibrium at matric water potentials of-168 MPa and lower (to-673 MPa=c0.12a w) the protoplast shrinks, but the cells maintain the same size and diameter as those at-2,156 kPa (MN medium; control); the sheath expands and remains attached to the cell wall outer membrane by fibrils. The cell wall, cell membrane, thylakoid membranes, cyanophycin granules and carboxysomes appeared intact in desiccated cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00408014
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  • 29
    Digitale Medien
    Digitale Medien
    Role of glandular scales of lepidote rhododendrons in insect resistance (1984)
    Springer
    Journal of chemical ecology 10 (1984), S. 1787-1798 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Coleoptera ; Curculionidae ; Otiorhynchus sulcatus (F.) ; black vine weevil ; Ericaceae ; Rhododendron ; trichomes ; glandular scales ; essential oils ; volatiles ; plant resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Glandular scales on selected lepidote rhododendron species varied in density from 109 ± 13 to 4180 ± 60/cm2 of leaf surface. Globules contained within the scales stained with Sudan IV, a lipophilic dye. Essential oil contents of the scales varied with species from 24 ± 8 to 151 ± 35 ng/scale. Black vine weevil [(Otiorhynchus sulcatus (F.)] feeding on leaves from a sample of rhododendron species was inversely related to leaf essential oil content, and weevil feeding on membrane filters was inhibited by application of essential oil extracts from leaves of most lepidote rhododendrons tested. Results suggest that the glandular scales of the lepidote rhododendrons function, at least in part, in plant defense against insects.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00987361
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  • 30
    Digitale Medien
    Digitale Medien
    Attraction of bark beetles (Coleoptera: Scolytidae) to a pheromone trap (1984)
    Springer
    Journal of chemical ecology 10 (1984), S. 723-752 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Ips typographus ; pheromone ; release ; recapture ; diffusion ; model ; Coleoptera ; Scolytidae ; trap ; marking ; dispersal
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The movement of bark beetles near an attractive pheromone source is described in terms of mathematical models of the diffusion type. To test the models, two release experiments involving 47,000 marked spruce bark beetles [Ips typographus (L.)] were performed. The attractive source was a pheromone trap, surrounded by eight concentric rings with eight passive trap stations on each ring. Captures were recorded every 2–10 minutes for the pheromone trap and once for the passive traps. The models were fitted to the distribution in time of the central pheromone trap catch and to the spatial distribution of catch among the passive traps. The first model that gives a reasonable fit consists of two phases: Phase one—After release the beetles move according to a diffusion process with drift towards the pheromone trap. The strength of the drift is inversely proportional to the distance from the traps. Phase two—those beetles attracted to, but not caught by, the pheromone trap are no longer influenced by the pheromone, and their movement is described by a diffusion process without drift. In phase two we work with a loss of beetles, whereas the experiment seems to indicate that the loss of beetles in phase one is negligible. As a second model, the following modification of phase one is considered: After release the beetles move according to a diffusion process without drift, until they start responding to the pheromone (with constant probability per unit time), whereafter they start moving according to a diffusion process with drift. This study, like other release experiments, shows that the efficiency of the pheromone trap is rather low. What is specific for the present investigation is that we try to explain this low efficiency in terms of dynamic models for insect movement. Two factors seem to contribute: Some beetles do not respond to pheromone at all, and some beetles disappear again after having been close to the pheromone trap. It also seems that the motility of the beetles decreased after they ceased responding to the pheromone. Furthermore, the data lend some support to the hypothesis that flight exercise increases the response of the beetles to pheromone.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00988539
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  • 31
    Digitale Medien
    Digitale Medien
    Receptor cells inIps typographus andDendroctonus micans specific to pheromones of the reciprocal genus (1984)
    Springer
    Journal of chemical ecology 10 (1984), S. 759-769 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Ips typographus ; Dendroctonus micans ; Coleoptera ; Scolytidae ; exo-brevicomin ; (+)-ipsdienol ; single-cell recordings ; interspecific attraction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Olfactory receptor cells were studied electrophysiologically inIps typographus andDendroctonus micans. The investigation revealed cells which were keyed to pheromone compounds characteristic of the reciprocal genus. Thus, cells keyed toexo-brevicomin were found inI. typographus, whereas cells keyed to (+)-ipsdienol were present inD. micans. Laboratory behavioral tests indicated an attractive effect of the two compounds on beetles of the reciprocal genus. InI. typographus the effect ofexo-brevicomin predominantly concerned males and enhanced their response to the pheromone “ipslure.” It is suggested thatexo-brevicomin serves as an interspecific attractant forI. typographus, which may be guided by pheromone compounds of the reciprocal genus in finding suitable breeding material. The function of (+)-ipsdienol inD. micans is more uncertain. It may be either a pheromone or an interspecific messenger.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00988541
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  • 32
    Digitale Medien
    Digitale Medien
    Olfaction in the boll weevil,Anthonomus grandis Boh. (Coleoptera: Curculionidae): Electroantennogram studies (1984)
    Springer
    Journal of chemical ecology 10 (1984), S. 1759-1785 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Cotton boll weevil ; Anthonomus grandis ; Coleoptera ; Curculionidae ; pheromone ; kairomone ; plant odor ; olfaction ; electroantennogram ; attractant ; host plant ; green leaf volatiles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Electroantennogram (EAG) techniques were utilized to measure the antennal olfactory responsiveness of adult boll weevils,Anthonomus grandis Boh. (Coleoptera: Curculionidae), to 38 odorants, including both insect and host plant (Gossypium hirsutum L.) volatiles. EAGs of both sexes were indicative of at least two receptor populations: one receptor population primarily responsive to pheromone components and related compounds, the other receptor population primarily responsive to plant odors. Similar responses to male aggregation pheromone components (i.e., compounds I, II, and III + IV) were obtained from both sexes, but females were slightly more sensitive to I. Both sexes were highly responsive to components of the “green leaf volatile complex,” especially the six-carbon saturated and monounsaturated primary alcohols. Heptanal was the most active aldehyde tested. More acceptors responded to oxygenated monoterpenes than to monoterpene hydrocarbons. β-Bisabolol, the major volatile of cotton, was the most active sesquiterpene. In general, males, which are responsible for host selection and pheromone production, were more sensitive to plant odors than were females. In fact, males were as sensitive to β-bisabolol and heptanal as to aggregation pheromone components. Electrophysiological data are discussed with regard to the role of insect and host plant volatiles in host selection and aggregation behavior of the boll weevil.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00987360
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  • 33
    Digitale Medien
    Digitale Medien
    Quantitative variation of pheromone components in the spruce bark beetleIps typographus from different attack phases (1984)
    Springer
    Journal of chemical ecology 10 (1984), S. 1029-1055 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Ips typographus ; spruce bark beetle ; Coleoptera ; Scolytidae ; 2-methyl-3-buten-2-ol ; ipsenol ; cis-verbenol ; ipsdienol ; trans-verbenol ; verbenone ; myrtenol ; trans-myrtanol ; 2-phenylethanol ; ß-isophorone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Ips typographus beetles were collected in the field, separated into eight attack phases (from beetles walking on the trunk of a tree under attack to those excavating gallery systems with a mother gallery longer than 4 cm), and immediately frozen in liquid nitrogen. 2-Methyl-3-buten-2-ol,cis- andtrans-verbenol, verbenone, myrtenol, trans-myrtanol, ipsenol, ipsdienol, and 2-phenylethanol were quantified from excised hindguts against an internal standard, heptyl acetate, in the extraction solvent. Methylbutenol, the pinene alcohols, and 2-phenylethanol showed the same pattern of variation between attack phases in males, with the largest amounts present before accepting females and then a fast decline. Ipsenol and ipsdienol were not detected in males before the females were accepted, and the amounts increased when the females start their egg laying. Verbenone occurred only in trace amounts. The beetles were sampled from five Norway spruce trees (Picea abies) of differing resin flow. The correlations between the nine pheromone components and five major host monoterpenes in the gut showed that the variation in the amount of methyl-butenol, ipsenol, and ipsdienol could not be explained by the variation in the amounts of host monoterpenes. In contrast over 80% of the quantitative variation ofcis-verbenol,trans-verbenol, and myrtenol was explained by the amount of α-pinene. The nine pheromone components from 36 individual males were also quantified. Both methylbutenol andcis-verbenol showed a large variation in both amounts and proportions. Females containedtrans-verbenol and traces of most other components found in males. When accepted by the male, they also contained a female-specific compound, β-isophorone. Behavioral and biosynthetic implications of the results are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00987511
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  • 34
    Digitale Medien
    Digitale Medien
    Multifunctionality of douglas-fir beetle pheromone 3,2-mch confirmed with solvent dibutyl phthalate (1980)
    Springer
    Journal of chemical ecology 6 (1980), S. 193-201 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Coleoptera ; Scolytidae ; Dendroctonus pseudotsugae ; pheromone ; multifunctionality ; 3-methylcyclohex-2-en-l-one ; diluent ; dibutyl phthalate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Previous field and laboratory tests withDendroctonus pseudotsugae showing increased attractancy and chirp evocation by very low concentrations of the pheromone 3-methylcyclohex-2-en-1-one (3,2-MCH) dissolved in ethanol with known attractants were repeated with a different diluent, dibutyl phthalate (DBP). Other workers had speculated that the solvent ethanol was actually the synergist. Beetle response was essentially identical with both solvents, confirming the concentration-dependent multifunctionality of 3,2-MCH in Douglas-fir beetle behavior. Contradictions in available data with ethanol indicate unanswered questions about its effect withDendroctonus attractants.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00987538
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  • 35
    Digitale Medien
    Digitale Medien
    Enantiomer-based specificity in pheromone communication by two sympatricGnathoirichus species (Coleoptera: Scolytidae) (1980)
    Springer
    Journal of chemical ecology 6 (1980), S. 445-456 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Gnathotrichus retusus ; G. sulcatus ; Coleoptera ; Scolytidae ; ambrosia beetle ; aggregation pheromone ; 6-methyl-5-hepten-2-ol ; sulcatol ; reproductive isolation ; enantiomers ; chiral compounds
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The aggregation pheromone ofGnathotrichus retusus was isolated and identified as (S)-(+)-sulcatol (6-methyl-5-hepten-2-ol). In laboratory and field experiments,G. retusus responded to (S)-(+)-sulcatol, but not to (±)-sulcatol, which was attractive to the sympatric species,G. sulcatus. G. sulcatus did not respond to optically pure (S)-(+)-sulcatol, but began to respond when ⩾ 1% (R)-(−)-sulcatol was present in an enantiomeric mixture.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01402921
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  • 36
    Digitale Medien
    Digitale Medien
    Estimating western pine beetle-caused tree mortality for evaluating an attractive pheromone treatment (1980)
    Springer
    Journal of chemical ecology 6 (1980), S. 853-866 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Ponderosa pine mortality ; Dendroctonus brevicomis ; Coleoptera ; Scolytidae ; aerial photography ; detection ; estimation ; sampling ; mapping ; attractive pheromones
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Sequential aerial photography was used to detect ponderosa pine trees killed by successive generations of the western pine beetle (WPB),Dendroctonus brevicomis Lec., over a three-year period during a study to evaluate the effectiveness of attractive pheromones for the suppression and survey of WPB. The total number of WPB-killed trees were estimated for each generation, using probability-proportional-to-size sampling procedures. Infested trees at the beginning of the suppression treatment totaled 283. Attacks by three successive WPB generations in 1970 killed 90,83, and 91 trees, respectively. The first generation in 1971 killed 47 trees and the two subsequent generations combined killed a total of 49 trees. During the suppression treatment, tree mortality was concentrated into the suppression plots in comparison to the check plots and the surrounding area. By 1972, tree mortality distribution returned to its original pattern, but at one-tenth the original level, as shown by maps. Recommendations suggest ways to improve the use of aerial photography for studies of WPB-caused tree mortality and population dynamics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00990469
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  • 37
    Digitale Medien
    Digitale Medien
    Insect feeding and oviposition deterrents from western red cedar foliage (1981)
    Springer
    Journal of chemical ecology 7 (1981), S. 39-48 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Insect feeding deterrents ; antifeedants ; Pissodes strobi Peck ; Coleoptera ; Curculionidae ; Thuja plicata Donn
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The feeding deterrent activity of fractions from the foliage of western red cedar,Thujaplicata Donn, was studied in laboratory bioassays using the white pine weevil,Pissodes strobi Peck, as a test insect. The most active fraction was the volatile mixture that comprises the leaf oil of this tree species. Further fractionation of the leaf oil indicated feeding deterrent activity in the monoterpene hydrocarbon, thujone, and terpene alcohol fractions. When tested alone, both (−)-3-isothujone and (+)-3-thujone, which made up 75–88% and 5–10% of the leaf oil, respectively, deterred feeding by the weevils. Western red cedar leaf oil also showed antifeedant activity with the alder flea beetle,Altica ambiens (Le Conte), and served as an oviposition deterrent for the onion root maggot,Hylemya antiqua Meigen. The leaf oil, however, had no inhibitory effect on the feeding of the leaf roller,Epinotia solandriana L., and the red-backed sawfly,Eriocampa ovata L.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00988634
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  • 38
    Digitale Medien
    Digitale Medien
    Electroantennogram responses ofScolytus multistriatus (Coleoptera: Scolytidae) to its pheromone components and to associated compounds (1982)
    Springer
    Journal of chemical ecology 8 (1982), S. 1333-1344 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Coleoptera ; Scolytidae ; Scolytus multistriatus ; pheromone ; insect olfaction ; electroantennogram ; electrophysiology ; differential adaptation ; multistriatin ; 4-methyl-3-heptanol ; α-cubebene
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Electroantennograms were recorded fromScolytus multistriatus in response to 4-methyl-3-heptanol, the four geometric isomers of multistriatin, and cubeb oil. Charateristic dose-response curves for response amplitude and the time required for the voltage trace to return to 1/2 baseline (recovery rate) were established. Recovery rates were significantly more rapid following stimulation with 4-methyl-3-heptanol or cubeb oil than with the multistriatin isomers. At most intensities, α-multistriatin, the isomer that evokes behavioral response, gave significantly larger EAGs with significantly longer recovery rates than the other isomers. Results of differential adaptation experiments suggested that 4-methyl-3-heptanol interacted with the processes involving multistriatin and cubeb oil activity. However, cross-activity of acceptors for these compounds seems unlikely; single sensillum recordings are needed to ascertain the response spectra for individual receptor neurons.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01403097
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  • 39
    Digitale Medien
    Digitale Medien
    Frontalin in the male mountain pine beetle (1982)
    Springer
    Journal of chemical ecology 8 (1982), S. 1399-1409 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Coleoptera ; Scolytidae ; Dendroctonus ponderosae ; pheromone ; frontalin ; exo-brevicomin ; Pinns contorta ; Pinus ponderosa
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Frontalin andexo-brevicomin were identified by GC-MS in air drawn over maleDendroclonus ponderosae Hopk. (MPB) from Oregon that had joined females for 1–2 days in the bark of lodgepole and ponderosa pine logs. Unfed males releasedexo- andendo-brevicomin but not frontalin. These three compounds were not detected in either unfed or fed females. Arrestment of males bytrans-verbenol and terpenes in an olfactory walkway was reduced by the addition of racemic frontalin; production of attractant chirps also diminished. Racemic frontalin also strongly reduced the aggregation of MPB in lodgepole and ponderosa pine stands to sticky traps baited with the aggregation pheromonetrans-verbenol and host terpenes; however, the function of the natural enantiomer of frontalin in MPB is unknown.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01403103
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  • 40
    Digitale Medien
    Digitale Medien
    Defensive secretions of three oxytelinae rove beetles (Coleoptera: Staphylinidae) (1982)
    Springer
    Journal of chemical ecology 8 (1982), S. 1411-1420 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Coleoptera ; Staphylinidae ; Oxytelinae ; defensive secretion ; glands ; acetates ; lactones ; alkenes ; quinones ; citral
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The secretions of the abdominal glands ofBledius spectabilis Kraatz,Platystethus arenarius Fourcr., andOxytelus piceus L. have been shown to contain four 1-alkenes; toluquinone; toluhydroquinone; C10 −-,C11 −, C12 −-, and C14 − γ-lactones; C12-δ-lactone; citral; and decyl-, undecyl-, and dodecyl acetates. Quantitative results indicate that 1-alkenes are formed probably from present lactones by decarboxylation. According to the known life histories of the beetles, it is suggested that the gland material is not used as an algal growth regulator but represents a unique defensive blend characteristic for the whole subfamily.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01403104
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  • 41
    Digitale Medien
    Digitale Medien
    Olfactory responses of adultTribolium castaneum (Herbst), to volatiles of wheat and millet kernels, milled fractions, and extracts (1982)
    Springer
    Journal of chemical ecology 8 (1982), S. 1463-1472 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Red flour beetle ; Tribolium castaneum ; Coleoptera ; Tenebrionidae ; food volatiles ; olfactory responses ; olfactometer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Olfactory responses of 72- to 96-hr-old, 24-hr starved adult male, female, or mixed-sex groups of the red flour beetle,Tribolium castaneum (Herbst), to volatiles from wheat and millet kernels, certain milled fractions, and solvent extracts were recorded by using a lightsensitive apparatus. Wheat-germ volatiles from intact germ or solvent extracts were generally more attractive than volatiles of wheat endosperm or wheat bran. Volatiles of whole wheat kernels were the least attractive among test materials of wheat origin, whereas there were no significant differences among whole wheat flour, germ, and endosperm. Wheat-germ extracts, however, were more attractive than were extracts of the other fractions. Whole millet flour or fermented millet flour volatiles were more attractive than those from whole millet kernels or millet starch. Beetles reached maximum responsiveness to grain volatiles by 72–96 hr after adult ecdysis. Groups of virgin female beetles generally were more responsive than male or mixed-sex groups to volatiles of substances tested.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00989103
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  • 42
    Digitale Medien
    Digitale Medien
    Influence of opposite sex on attraction produced by pioneer sex of four bark beetle species cohabiting pine in the Southern United States (1982)
    Springer
    Journal of chemical ecology 8 (1982), S. 373-378 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Dendroctonus frontalis ; Ips calligraphus ; I. grandicollis ; I. avulsus ; Coleoptera ; Scolytidae ; mating ; attraction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Catches ofDendroctonus frontalis andIps avulsus on traps surrounding bolts infested with both sexes of each species in the gallery were not significantly different from catches at bolts infested only with the sex which normally pioneers the host colonization process. In contrast, the presence of the second sex in the gallery significantly reduced catches ofI. grandicollis andI. calligraphus and, additionally, the presence of females in the male galleries ofI. calligraphus significantly reduced the catch ofI. avulsus females as compared with their response to bolts infested with the maleI. calligraphus only.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00987785
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  • 43
    Digitale Medien
    Digitale Medien
    Defensive adaptations of eggs and adults ofGastrophysa cyanea (Coleoptera: Chrysomelidae) (1982)
    Springer
    Journal of chemical ecology 8 (1982), S. 453-462 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Defensive secretions ; oleic acid ; hydrocarbons ; terpenoids ; eggs ; deterrents ; ants ; predation ; Chrysomelidae ; Coleoptera ; Gastrophysa cyanea ; reflex bleeding ; elytral glands
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Egg clusters and adults ofGastrophysa cyanea are conspicuous and, like their larvae, are chemically protected. The eggs owe their bright yellow color primarily to β-carotene and, in addition, contain substantial quantities of oleic acid. At natural concentrations oleic acid effectively deters many species of ants from feeding. The use of fatty acids as deterrents against ants is discussed as a possible widespread phenomenon among insects. During defensive confrontations, adults ofG. cyanea exhibit avoidance behavior and may also feign death. In addition, the adults may autohemmorhage or secrete a fluid from elytral or pronotal pores in response to traumatic stimuli. The secretions are effective against ants and contain a mixture of hydrocarbons as well as terpenoid components. The pattern of ontogenetic modification in the defensive chemical repertoire ofG. cyanea is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00987793
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  • 44
    Digitale Medien
    Digitale Medien
    Responses of the olfactory receptors ofScolytus scolytus (F.) (Coleoptera: Scolytidae) to the stereoisomers of 4-methyl-3-heptanol (1982)
    Springer
    Journal of chemical ecology 8 (1982), S. 477-492 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Scolytus scolytus ; Coleoptera ; Scolytidae ; pheromone ; 4-methyl-3-heptanol stereoisomer ; olfaction ; electrophysiology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Electroantennogram (EAG) and single-cell recording techniques have been used to demonstrate the presence of separate receptors for (−)-threo- and (−)-erythro-4-methyl-3-heptanol on the antenna ofS. scolytus. The majority of single-cell recordings showed spikes of two different amplitudes. The cell giving spikes of larger amplitude responded to the (−)-threo stereoisomer while the cell with the small-amplitude spikes responded to (−)-erythro-4-methyl-3-heptanol. It is suggested that in most recordings the two cells are associated with a single sensillum basiconicum.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00987796
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  • 45
    Digitale Medien
    Digitale Medien
    Regeneration and biosynthesis of dytiscid defensive agents (Coleoptera: Dytiscidae) (1983)
    Springer
    Journal of chemical ecology 9 (1983), S. 1449-1464 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Coleoptera ; Dytiscidae ; Agabus seriatus ; Agabus obtusatus ; defensive secretions ; steroids ; regeneration ; pygidial glands ; prothoracic glands ; cholesterol
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The defensive secretions of the dytiscid species,Agabus seriatus (Say) andAgabus obtusatus (Say), were qualitatively and quantitatively analyzed by high-pressure liquid chromatography. The intrinsic ability ofA. Seriatus andA. Obtusatus to regenerate their prothoracic gland defensive secretions under laboratory conditions was determined by analyzing the secretions every seventh day for five weeks. Both beetles regenerated ∼ 80% of their prothoracic gland components within two weeks.A. seriatus was injected with [4-14C]cholesterol and after a three-week regeneration period 7.5% of the14Clabel was found in the steroidal defensive secretion from the prothoracic glands.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00988511
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  • 46
    Digitale Medien
    Digitale Medien
    1-Methylcyclohex-2-en-1-ol as an aggregation pheromone ofDendroctonus pseudotsugae (1983)
    Springer
    Journal of chemical ecology 9 (1983), S. 1533-1541 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Aggregation pheromone ; attractant ; 1-methylcyclohex-2-en-1-ol ; Dendroctonus pseudotsugae ; Coleoptera ; Scolytidae ; bark beetle ; Douglas-fir beetle ; 3-methylcyclohex-3-en-1-ol ; Pseudotsuga menziesii
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract 1-Methylcyclohex-2-en-1-ol (1,2-MCH-ol) was synthesized, identified as a compound found in volatiles of the female Douglas-fir beetle, and shown by bioassays to be an aggregation pheromone. 1,2-MCH-ol matches in both GC retention index and mass spectrum a compound released by the female after feeding. 3,3-MCH-ol was also synthesized as a candidate compound; its mass spectrum is presented because published mass spectra are incorrect for this compound. Synthetic 1,2-MCH-ol increased arrestment and stridulation of males in olfactory walkways and increased trap catches of flying beetles. Males were more responsive to 1,2-MCH-ol than females.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00988419
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  • 47
    Digitale Medien
    Digitale Medien
    Ethanol and other host-derived volatiles as attractants to beetles that bore into hardwoods (1983)
    Springer
    Journal of chemical ecology 9 (1983), S. 181-190 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Coleoptera ; Buprestidae ; Cerambycidae ; Cleridae ; Scolytidae ; wood-boring beetles ; bark beetles ; ethanol ; host attractants ; hardwood tree insects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Ethanol, methanol, acetone, and acetaldehyde—chemicals identified in the inner bark of living trees—were used to bait vane traps placed in crowns of oak trees in Connecticut. Ethanol-baited traps caught more cerambycid, scolytid, and clerid beetles than unbaited traps. Buprestidae were not attracted to ethanol. Acetaldehyde and acetone were not attractive to any family. A mixture of ethanol, methanol, and acetaldehyde was no more attractive than ethanol alone. The vane traps were very effective at catching Cerambycidae and Scolytidae, but ineffective compared to sticky panels at catching Buprestidae.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00988035
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  • 48
    Digitale Medien
    Digitale Medien
    Sensitivity of antennae of male and femaleIps paraconfusus (Coleoptera: Scolytidae) to their natural aggregation pheromone and its enantiomeric components (1983)
    Springer
    Journal of chemical ecology 9 (1983), S. 561-584 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Coleoptera ; Scolytidae ; bark beetle ; Ips paraconfusus ; aggregation pheromone ; enantiomer ; electrophysiology ; electroantennogram ; interruption ; allomone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Antennae of male and femaleIps paraconfusus were equally and highly sensitive to their male-produced, multicomponent aggregation pheromone. Female and male antennae were highly sensitive to the pheromonal component, (S)-(−)-ipsenol, but essentially insensitive to its antipode, (R)-(+)-ipsenol. Further, female and male antennae were more sensitive to the pheromonal component, (S)-cis-verbenol, than to its antipode, (R)-cis-verbenol. Dramatic sexual dimorphism in chiral sensitivity to the ipsdienol enantiortiers was found, with female antennae being more sensitive to the conspecific pheromonal enantiomer, (S)-(+)-ipsdienol, and male antennae being more sensitive to the antipode, (R)-(−)-ipsdienol. Since (R)-(−)-ipsdienol is the principal pheromone of CaliforniaIps pini and interruptsI. paraconfusus aggregation, male antennae appear to be more sensitive to an interspecific allomone than a conspecific pheromone. Of the conspecific pheromonal enantiomers, both male and female antennae were most sensitive to (S)-(+)-ipsdienol, intermediately sensitive to (S)-(−)-ipsenol, and least sensitive to (S)-cis-verbenol. However, when enantiomeric sensitivities were compared to the estimated concentrations of these components in the natural pheromone, (S)-(~)-ipsenol tended to equal or approach the potency of (S)-(+)-ipsdienol as an antennal stimulant, while antennal responsiveness to (S)-cis-verbenol was dramatically less than for the other two pheromonal components. The behavioral implications of such physiological sensitivities are discussed in regard to perception of multicomponent synergistic pheromones and the relative efficacy of each component as an orientation cue.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00990410
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  • 49
    Digitale Medien
    Digitale Medien
    Sensitivity of antennae of male and femaleIps paraconfusus (Coleoptera: Scolytidae) to its pheromone and other behavior-modifying chemicals (1983)
    Springer
    Journal of chemical ecology 9 (1983), S. 585-606 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Coleoptera ; Scolytidae ; bark beetle ; Ips paraconfusus ; pheromone ; enantiomer ; electrophysiology ; electroantennogram ; interruption ; allomone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The antennal sensitivities of both male and femaleIps paraconfusus were found generally to be greatest for conspecific aggregation pheromones (ipsdienol, ipsenol); intermediate for an additional conspecific pheromone (cis-verbenol), an aggregation synergist (2-phenylethanol), and pheromones/allomones of sympatric species (trans-verbenol, verbenone, and frontalin); and lowest for both host terpenes (alpha-pinene and myrcene) and other bark beetle-produced odorants (exo-brevicomin and linalool). Of the enantiomeric compounds tested, antennae of both sexes did not differ in sensitivity between thetrans-verbenol enantiomers at low dosage levels; but at higher dosages, the conspecific-produced enantiomer, (1R,4S,5R)-(+)-trans-verbenol, elicited larger mean EAG responses than its antipode, (1S,4R, 5S)-(−)-trans-verbenol. At the mid-dosage range, female antennae tended to be slightly more responsive to (S)-(−)-verbenone than to (R)-(+)-verbenone, while male antennae were equally responsive to stimulations by either verbenone enantiomer. In field bioassays there was a large and significant reduction in trap catches ofI. paraconfusus on traps where the (S)-(−)- or (R)-(+)-enantiomers of verbenone were evaporated beside logs containing boring conspecific males. Only when the (S)-(−)-enantiomer of verbenone was evaporated beside logs containing boring males did the sex ratio ofI. paraconfusus trapped shift from female-dominated to male-dominated attraction. Thus both physiological and behavioral data suggest a differential chiral sensitivity of female beetles for the verbenone enantiomers. The relative sensitivities between different chiral compounds derived from one or the other of the common precursoral host terpenes, (S)-(−)- and (R)-(+)alpha-pinene or myrcene, are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00990411
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  • 50
    Digitale Medien
    Digitale Medien
    Seasonal variation in laboratory response to behavioral chemicals of the southern pine beetle (1982)
    Springer
    Journal of chemical ecology 8 (1982), S. 641-652 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Dendroctonus frontalis ; Coleoptera ; Scolytidae ; seasonal variation ; pheromone content ; environmental parameters
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The response ofDendroctonus frontalis to an attractant mixture (frontalin,trans-verbenol, and loblolly pine turpentine) was measured in the laboratory over a four-year period. Beetle response was highest in late winter and early spring, and lowest in midsummer and early fall. Males consistently responded higher than females. Female beetles displayed significantly higher responses in early morning and late afternoon than in the middle of the day. Analysis of beetle pronotal width and fat content revealed a high degree of correlation between these two parameters in female beetles, but there was no correlation of response with either fat content or pronotal width for either sex. There was no evident relationship between mean monthly beetle response and total amounts of frontalin andtrans-veibenol found in hindgut extracts. Daily temperature in months both during which beetles were bioassayed and immediately prior to bioassay was highly correlated to response to the attractant.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00989633
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  • 51
    Digitale Medien
    Digitale Medien
    Oscillatoria Sp. (Cyanophyta) mat metabolites implicated in habitat selection inBembidion obtusidens (Coleoptera: Carabidae) (1982)
    Springer
    Journal of chemical ecology 8 (1982), S. 671-678 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Bembidion obtusidens ; Coleoptera ; Carabidae ; Oscillatoria animalis ; Oscillatoria subbrevis ; Cyanophyta ; metabolites ; volatiles ; ecophenes ; methylhexadecanoate ; methyloctadecenoate ; attractant ; habitat selection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract In laboratory bioassaysBembidion obtusidens Fall adults were attracted to volatile metabolites (methyl esters of hexadecanoic and 9-octadecenoic acid) of mat-forming, filamentous blue-green algae (Oscilalatoria sp.; Cyanophyta) growing in the microhabitat of these beetles on the shores of saline lakes. Commercial preparations of these metabolites also were attractive, suggesting thatOscillatoria metabolites are token stimuli which serve as habitat cues forBembidion adults.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00989636
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  • 52
    Digitale Medien
    Digitale Medien
    Field bioassay ofexo- andendo-brevicomin withDendroctonus ponderosae in lodgepole pine (1982)
    Springer
    Journal of chemical ecology 8 (1982), S. 701-707 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Coleoptera ; Scolytidae ; Dendroctonus ponderosae ; pheromone ; exo-brevicomin ; endo-brevicomin ; Pinus contorta
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Bothexo- andendo-brevicomin reduced the response of flyingDendroctonus ponderosae (Coleoptera: Scolytidae) to an attractant composed oftrans-verbenol and terpenes or oftrans- andcis-verbenol and terpenes in a stand ofPinus contorta var.murrayana. These data suggest that racemicexo- andendo-brevicomin may interrupt aggregation in populations of mountain pine beetle colonizing lodgepole pine; functions of the natural chiral compounds are unknown.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00988311
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  • 53
    Digitale Medien
    Digitale Medien
    Defensive and pheromonal secretion of the tergal gland ofAleochara curtula II. Release and inhibition of male copulatory behavior (1983)
    Springer
    Journal of chemical ecology 9 (1983), S. 13-31 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Aleochara curtula (Goeze) ; Coleoptera ; Staphylinidae ; tergal gland secretion ; defense ; mating stimulants ; female sex pheromone ; hydrocarbons ; n-aldehydes ; substituted 1 ; 4-benzoquinones
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract At high concentrations, the defensive tergal gland secretion (TGS)3 of the staphylinid beetle,Aleochara curtula, inhibits the male copulatory response (grasping with parameres). Inhibitory chemicals, for which a function as alarm substances is assumed, aren-undecane, 1-undecene,n-dodecanal, toluquinone, and 2-methoxy-3-methyl-1,4-benzoquinone. When emitted in small amounts, however, the TGS releases the male grasping response. The main components with aphrodisiac effect are (Z)-4-tridecene,n-dodecanal, and (Z)-5-tetradecenal. These supplementary mating stimulants, which are not sex specific, work synergistically with the aphrodisiac female sex pheromone from thé epicuticular lipids and are discussed as alerting pheromones of short-term effect. Antennal movements of resting males as an indication of the recognition of a female and the approach to the mate are released at somewhat longer distances, when the TGS is additionally present.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00987767
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  • 54
    Digitale Medien
    Digitale Medien
    Field response of the dutch elm disease vectors,Scolytus multistriatus (Marsham) andS. scolytus (F.) (Coleoptera: Scolytidae) to 4-methyl-3-heptanol baits containing α-, β-,δ-, or δ-multistriatin (1983)
    Springer
    Journal of chemical ecology 9 (1983), S. 67-84 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Scolytus multistriatus ; S. scolytus ; Coleoptera ; Scolytidae ; elm bark beetle ; multistriatin stereoisomers ; Dutch elm disease ; aggregation pheromone ; field responses ; attractant baits
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The field responses of English populations of the Dutch elm disease vectors,Scolytus multistriatus andS. scolytus to baits containing 4-methyl-3-heptanol, a host synergist [(−)-α-cubebene or (−)-limonene] and (±)-α-, (+)-β-, (−)-β-, (±)-γ-, or (±)-δ-multistriatin were examined. (±)-α-Multistriatin, released at 5–10 μg/day, enhanced the response ofS. multistriatus to baits containing 4-methyl-3-heptanol and either of the host synergists but had no effect on the capture ofS. scolytus. The release of larger amounts (57 or 365 μg/day) of (±)-α-multistriatin interrupted the response of both species to the 4-methyl-3-heptanol baits. It appears that α-multistriatin has multiple functions as a behavior-modifying substance for the two beetles. The (+)-β-, (−)-β-, (±)-γ-, and (±)-δ-multistriatins were inactive when released at 5–10 μg/day. The results of these field experiments suggest that one bait can be formulated to capture both species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00987771
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  • 55
    Digitale Medien
    Digitale Medien
    Ecological patterns in the glucosinolate content of a native mustard,Cardamine cordifolia, in the rocky mountains (1983)
    Springer
    Journal of chemical ecology 9 (1983), S. 397-422 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Cruciferae ; chemical defense ; gradient ; glucosinolate ; herb-ivory ; insect-plant interactions ; Cardamine cordifolia ; Coleoptera ; Chrysomelidae ; Homoptera ; Psyllidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Insect use of native crucifers may be related to patterns in mustard oil content. Consequently, in 1979 we measured glucosinolate content of Rocky Mountain bittercress,Cardamine cordifolia (Cruciferae), using paper and gas chromatography, in relation to: plant organ, phenology, elevation, habitat, leaf position and weight, and plant consumption by two adapted insect herbivores. Results for each are as follows. (1) The predominant constituent in all vegetative organs was 2-butylglucosinolate; concentration of isothiocyanate-yielding glucosinolates (IYG) was highest in roots (1.11 mg/gfr. wt) and lowest in stems (0.07 mg/g). (2) Concentration of IYG appeared to be higher in plants lacking oxazolidinethione-yielding glucosinolates (OYG) than in those with OYG. (3) Terminal cauline leaves had a higher content of IYG than leaves in other positions on a plant. (4) Heavy leaves had significantly higher concentrations of IYG than did lighter leaves. (5) IYG concentrations were not directly related to elevation. (6) Leaves of plants occurring naturally in the sun had concentrations of IYG similar to those of plants in the usual shaded habitat. However, experimental removal of overhanging willows caused a significant, stress-induced increase in IYG concentrations. Finally, (7) feeding by two adapted herbivores, chrysomelids and psyllids, was associated with lower, rather than higher, IYG concentrations. The results demonstrate significant variation in glucosinolate content in a native crucifer and suggest that some of this variation can be partitioned in relation to the ecological and environmental axes examined.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00988458
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  • 56
    Digitale Medien
    Digitale Medien
    Isolation and identification of two macrolide pheromones from the frass ofCryptolestes ferrugineus (Coleoptera: Cucujidae) (1983)
    Springer
    Journal of chemical ecology 9 (1983), S. 451-474 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Cryptolestes ferrugineus ; rusty grain beetle ; aggregation ; pheromone ; macrolide ; (E,E)-4,8-dimethyl-4,8-decadien-10-olide ; (3Z,11S)-3-dodecen-11-olide ; (Z,Z)-3,6-dodecadien-11-olide ; (Z)-5-tetradecen-13-olide ; 11-dodecanolide ; 4-nonanolide ; Coleoptera ; Cucujidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Two synergistic macrolide aggregation pheromones were isolated from Porapak Q-trapped volatiles obtained from the frass ofCryptolestes ferrugineus (Stephens). These compounds were identified as (E,E)-4,8-dimethyl-4,8-decadien-10-olide (I) and (3Z,11S)-3-dodecen-11-olide (II) and given the trivial names ferrulactone I and II, respectively. Analysis of captured volatiles from separated male and female adults disclosed that the pheromones are male-produced. Additional macrolides were identified in frass volatiles, but were devoid of any pheromonal activity. The structures of I and II were confirmed by comparison with synthetic materials.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00990219
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  • 57
    Digitale Medien
    Digitale Medien
    Effect of soybean phytoalexins on the herbivorous insects mexican bean beetle and soybean looper (1983)
    Springer
    Journal of chemical ecology 9 (1983), S. 657-672 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Pseudoplusia includens ; soybean looper ; Lepidoptera ; Noctuidae ; Epilachna varivestis ; Mexican bean beetle ; Coleoptera ; Coccinellidae ; feeding preferences ; nutrition ; food utilization ; host-plant resistance ; induced resistance ; glyceollin ; isoflavonoids ; soybean ; phytoalexins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Effects of soybean phytoalexins on the feeding of the soybean looper and Mexican bean beetle were investigated to test the hypothesis that phytoalexins might be a defense mechanism of plants against insects as well as against pathogens. Short-term behavioral responses to the phytoalexins were analyzed using dual-choice tests with phytoalexin-rich and phytoalexin-poor (control) tissues. Phytoalexin production was elicited with ultraviolet radiation. Results from the dual-choice tests indicated that 6th instar soybean looper larvae fed equally on the control and phytoalexin-rich tissues. Feeding by adult and 4th instar Mexican bean beetles, however, was strongly deterred by the phytoalexins as evidenced by “single-bite” mandible scars on the phytoalexin-rich cotyledon discs. Nutritional effects of the isoflavonoid phytoalexin glyceollin on early instar soybean looper larvae were tested by incorporating the phytoalexin into an artificial medium at a level of 1% dry weight (0.15% fresh weight). The larvae were reared for 7 days from emergence on diets of control and glyceollin-containing media. Although survival on the glyceollin diets was initially less than on the control diets, under the experimental conditions glyceollin had no significant effect on the growth, development, or subsequent survival of the larvae. Efficiency of food utilization (ECI) was reduced, indicating that the phytoalexins may be a mild digestibility-reducing factor for the loopers. Implications of the results for host-plant resistance are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00988774
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  • 58
    Digitale Medien
    Digitale Medien
    Avoidance of nonprotein amino acid incorporation into protein by the seed predator,Caryedes brasiliensis (Bruchidae) (1983)
    Springer
    Journal of chemical ecology 9 (1983), S. 1353-1361 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Canavanine ; Caryedes brasiliensis ; Coleoptera ; Bruchidae ; Dioclea megacarpa ; plant-insect interactions ; amino acids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Larvae of the bruchid beetle,Caryedes brasiliensis (Bruchidae) have the ability to avoid significant incorporation ofl-canavanine, the guanidinooxy structural analog ofl-arginine, into de novo synthesized proteins. This ability is related to a highly discriminatory protein-synthesizing system which exhibits marked ability to avoid processing an array of nonprotein amino acids structurally related to arginine.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00994804
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  • 59
    Digitale Medien
    Digitale Medien
    Ultrastructure of gill epithelial cells of Diopatra neapolitana (Annelida, Polychaeta) (1984)
    Springer
    Zoomorphology 104 (1984), S. 304-309 
    Details
    ISSN: 1432-234X
    Schlagwort(e): Ultrastructure ; Gills ; Epithelial cells ; Polychaeta
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ultrastructure of gill epidermal cells of Diopatra neapolitana and their relationship with blood spaces are described. The existence of a basal infolding complex, related to the blood spaces, is also reported. A possible involvement of these cells in osmoregulation and ion interchange, apart from their well-known role in respiration, is suggested.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00312012
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  • 60
    Digitale Medien
    Digitale Medien
    Unequal distribution of plastids during generative cell formation in Impatiens (1984)
    Springer
    Theoretical and applied genetics 68 (1984), S. 305-309 
    Details
    ISSN: 1432-2242
    Schlagwort(e): Impatiens ; Microspore mitosis ; Plastid distribution ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary This paper describes the unequal distribution of plastids in the developing microspores of Impatiens walleriana and Impatiens glandulifera which leads to the exclusion of plastids from the generative cell. During the development from young microspore to the onset of mitosis a change in the organization of the cytoplasm and distribution of organelles is gradually established. This includes the formation of vacuoles at the poles of the elongate-shaped microspores, the movement of the nucleus to a position near the microspore wall in the central part of the cell, and the accumulation of the plastids to a position near the wall at the opposite side of the cell. In Impatiens walleriana, the accumulated plastids are separated from each other by ER cisterns, and some mitochondria are also accumulated. In both Impatiens species, the portion of the microspore in which the generative cell will be formed is completely devoid of plastids at the time mitosis starts.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00267882
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  • 61
    Digitale Medien
    Digitale Medien
    Degenerative regression of the digestive tract in the colonial ascidian Botryllus schlossen (Pallas) (1984)
    Springer
    Cell & tissue research 235 (1984), S. 309-318 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Ascidian ; Gut ; Cell involution ; Ultrastructure ; Phagocytes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Degenerative changes in the digestive tract of zooids of Botryllus schlosseri were studied by light and electron microscopy. Three main processes occurred in the tissues: contraction, involution and phagocytosis. The contraction of epidermis and peribranchial epithelium in which cytoplasmic microfilaments probably participate, seemed to have a special role in compressing the underlying organs. During contraction most of the body cavities collapsed, the branchial walls disintegrated and the fragments were rapidly taken up by large phagocytes. The gut epithelium retained its apparent continuity longer, though isolated phagocytes infiltrated it to eliminate single cells. Cell degeneration came about chiefly either through swelling and lysis of cells or through loss of water and condensation of cytoplasm and nucleus. The fate of all regressed tissues was to be engulfed and digested by wandering phagocytes. However, it was also observed that numerous cells of different epithelia could act as fixed phagocytes by engulfing cell debris and entire cells into heterophagic vacuoles.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00217855
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  • 62
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Blastocyst ; Ultrastructure ; Pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00217859
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  • 63
    Digitale Medien
    Digitale Medien
    Changes in human skeletal muscle induced by long-term eccentric exercise (1984)
    Springer
    Cell & tissue research 236 (1984), S. 365-372 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Skeletal muscles ; Myofibrils ; Ultrastructure ; Exertion ; Man
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The fine structure of muscle fibres from m. vastus lateralis of nine healthy males (mean age 26 years) was investigated. Four individuals constituted non-exercised controls while five subjects participated in a two-months eccentric muscular training program. Specimens from the controls showed a well-preserved, regular myofibrillar band pattern while changes in the myofibrillar architecture were constantly found in specimens taken after the training program. These changes consisted of Z-band alterations, Z-bands being out of register, extra sarcomeres, Z-band extensions and bisected Z-bands. Between the separated Z-band halves, thin and thick myofilaments as well as abundant glycogen particles and/or ribosomes, were observed. Type-2 (fast-twitch) fibres were predominantly affected. Contrary to the controls the trained individuals constantly showed a greater variation in sarcomere lengths in Type-2 fibres than in Type-1 fibres. It is concluded that muscular work of high tension can induce fine-structural alterations. When repeated over a long period of time, extreme tension demands seem to initiate reorganization in the muscle fibres, predominantly in the, ultrastructurally defined, Type-2 fibres. This adaptation probably results in a better stretchability of the muscle fibres, reduces the risk for mechanical damage and brings about an optimal overlap between actin and myosin filaments.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00214240
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  • 64
    Digitale Medien
    Digitale Medien
    Ultrastructure and morphometry of the stomach muscle of Amphiuma tridactylum (1984)
    Springer
    Cell & tissue research 236 (1984), S. 393-397 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Smooth muscle ; Salamander, Amphiuma ; Ultrastructure ; Stereology ; Volume: surface area ratio
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary An ultrastructural and stereological examination was performed on stomach smooth muscle of the salamander Amphiuma. This tissue has very large cells, ranging up to 12×1500 μm when relaxed. The extracellular space is 31% of the tissue volume, and the tissue contains 84.6% water. These values are similar to those of other amphibian and mammalian gastrointestinal smooth muscle. The cells possess the usual smooth muscle organelles. Thick, thin and intermediate filaments are present, along with membrane-associated and cytoplasmic dense regions. There is a well-developed sarcoplasmic reticulum and many microtubules. Caveolae are found in rows along the cellular surface; the caveolae increase the cellular surface area by about 70%. The ratio mean volume: surface area of the cells is 1.26 μm. This tissue appears to be typical of gastrointestinal smooth muscle, with the exception of the very large size of the cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00214243
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  • 65
    Digitale Medien
    Digitale Medien
    Reproduction and sexual development in a freshwater gastrotrich (1984)
    Springer
    Cell & tissue research 236 (1984), S. 619-628 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Gastrotricha, freshwater ; Sperm, reduced ; Ultrastructure ; Spermatogenesis ; Temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Spermatogenesis and spermiogenesis in Lepidodermella squammata are confined to the postparthenogenic phase of the life cycle and coincide with developmental changes in the bilateral female gonads. Male stages are bilateral but asynchronous, in the lateral abdomen anterior to the female gonads. Maximum observed sperm production is two packets per side, or 64 sperm. Sperm formation occurs more rapidly at 27° C than at 20° C (p〈0.001), requiring as little as 1 day. Two spermatogonial mitotic divisions produce a clone of four primary spermatocytes connected by bridges (stage 1). Centrioles are absent. Development occurs within a cyst. Meiotic divisions produce 16 spermatids (stage 2), each containing a dense, elongate, tapered nucleus. Cytoplasmic membranes enclose one end of the nuclear rod, excluding all other organelles. Completion of this process results in stage 3, a packet of 16 sperm associated with one dense sphere, a modified ‘residual body’ containing cytoplasmic debris. The residual body then disappears, leaving the sperm packet of stage 4. Each mature sperm is a dense nuclear rod with surrounding membranes, lacking acrosome, mitochondrion, centrioles, and flagellum. Function of sperm has not been demonstrated. The spermatozoa are of a reduced type not previously described.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00217231
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  • 66
    Digitale Medien
    Digitale Medien
    Reproduction and sexual development in a freshwater gastrotrich (1984)
    Springer
    Cell & tissue research 236 (1984), S. 629-636 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Oocytes, primary ; Gastrotricha, freshwater ; Ultrastructure ; Synaptonemal complex ; X-body
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Six small cells are present in each of the bilateral gonads of parthenogenically reproductive Lepidodermella squammata. Early in the extended postparthenogenic phase of the life history, these cells undergo limited proliferation followed by differentiation. Primary oocytes of three types are present 0.3 days after deposition of the final parthenogenic egg: small oocytes with presynaptic nuclei; intermediate oocytes with nuclei containing synaptonemal complexes; and larger oocytes with a germinal vesicle. Oocytes persist without further development at least until day four of the postparthenogenic phase. Older isolated animals may contain and even deposit an enlarged egg, but successful progeny does not result. Oocytes are located at the anterior pole of each of the bilateral gonads, adjacent to developing male tissues producing sperm. More posterior cells in the gonad are initially undifferentated in the postparthenogenic phase. Dorsal and central cells first show specialization for secretory activity, and by day four contain peripheral layers of RER and central accumulations of polymorphic secretion droplets. The posterior and ventral cells produce secretion droplets that aggregate into an enlarging bilobed structure called the X-body. Two or three cells in each gonad contribute secretions to the X-body, which is intracellular in a secondary syncytium formed by the contributing cells. Functions for the postparthenogenic gametes and for the X-body are not yet demonstrated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00217232
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  • 67
    Digitale Medien
    Digitale Medien
    Arachnoid mater of the bullfrog, Rana catesbeiana (1984)
    Springer
    Cell & tissue research 236 (1984), S. 693-697 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Intermediate filaments ; Microtubules ; Caveolae ; Bullfrog ; Arachnoid mater ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In the bullfrog, the meninges surrounding the central nervous system include an arachnoid mater that contains layers of cells with abundant intermediate filaments (IFs) having unique organizational characteristics. This membrane contains an inner lamina of cells that resemble fibroblasts and an outer lamina of flattened cells that are almost filled with IFs. The IFs of the outer arachnoid are arranged in compact, arching bundles that lie parallel to the outer surface of the central nervous system. Thus, sections cut tangentially to the membrane reveal bending of filament bundles, whereas transverse sections do not. In some cells bordering the subdural space, bundles of filaments are organized into highly-ordered spiral arrays. Attachments to the numerous desmosomes and, apparently, to the nuclear envelope suggest anchoring of cytoplasmic structures by the IF system. Microtubules occur primarily near the plasma membrane and the nucleus. Numerous caveolae also are associated with the plasma membrane. The unusual abundance, organization, and cytoplasmic relations of IFs in the bullfrog arachnoid suggest that this membrane may serve as an important model for study of fundamental cytoskeletal relations and function.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00217240
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  • 68
    Digitale Medien
    Digitale Medien
    Ultrastructure and innervation of the swimbladder of Tetractenos glaber (Tetraodontidae) (1984)
    Springer
    Cell & tissue research 237 (1984), S. 277-284 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Swimbladder ; Teleost ; Cholinergic nerves ; Adrenergic nerves ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The general structure, ultrastructure and innervation of the swimbladder of the smooth toadfish, Tetractenos glaber, were examined with light-microscopic, fluorescence-histochemical, and transmission electron-microscopic techniques. The structure of the swimbladder is similar to that of other euphysoclists. Fluorescence histochemistry showed adrenergic fibres in both the secretory and resorptive areas of the swimbladder. Transmission electron microscopy revealed two morphologically distinct axon profiles type-I profiles containing many small, flattened vesicles; type-II profiles containing both large, granular vesicles and rounded, small clear vesicles in varying proportions. The gas-gland cells and surrounding muscularis mucosae are innervated by both type-I and type-II fibres. Type-I fibres also innervate pre-rete arteries. The rete- and gas-gland capillaries do not appear to be innervated. Arteries running to the resorptive area are innervated by type-I fibres. Both type-I and type-II profiles make contact with the muscularis mucosae in the resorptive area. Only type-I fibres innervate the radial dilator muscle in the oval sphincter region, whereas only type II fibres innervate the circular muscle of the oval sphincter. Type-I fibres took up α-methyl-noradrenaline, and could not be found after pre-treatment with 6-hydroxydopamine. They are, therefore, assumed to be adrenergic. Type-II fibres were tentatively identified, by exclusion, as cholinergic.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00217146
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  • 69
    Digitale Medien
    Digitale Medien
    Fine structure of regenerating scales and their associated cells in the cichlid Hemichromis bimaculatus (Gill) (1984)
    Springer
    Cell & tissue research 237 (1984), S. 537-547 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Scale ; Regeneration ; Ultrastructure ; Cichlid ; Hemichromis bimaculatus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Scale regeneration has been studied in Hemichromis bimaculatus. The removed scale, which serves as a control, is covered by its surrounding scleroblasts as can be seen with scanning electron microscopy. Subsequently, during regeneration, a population of scleroblasts arises in the empty dermal pocket as shown with transmission electron microscopy. At first, an elongated papilla of regeneration forms, probably from the differentiation of dermal fibroblasts. A scale anlage composed of the osseous layer appears in the middle of the papilla, which becomes a regenerating bag. All the surrounding large scleroblasts are involved in scale formation, although later three populations of scleroblasts specialize according to their location around the scale. Superficial scleroblasts flatten when the final thickness of the osseous layer of the scale is attained; the deep scleroblasts are responsible for the formation of the basal plate whereas marginal scleroblasts increase the diameter of the osseous layer of the scale. During scale regeneration, scleroblasts are more numerous and larger than during scale ontogenesis. In particular, deep scleroblasts form a columnar epithelium when the basal plate is laid down, a feature which is not found during scale ontogenesis. Moreover, the regenerated basal plate exhibits an orthogonal “plywood” arrangement that is never seen in the embryonic scale where the “plywood” is of the intermediate type.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00228438
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  • 70
    Digitale Medien
    Digitale Medien
    Ultrastructure of the epididymis of the tammar, Macropus eugenii, and its relationship to sperm maturation (1984)
    Springer
    Cell & tissue research 237 (1984), S. 525-535 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Epididymis (marsupials) ; Ultrastructure ; Sperm maturation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ductus epididymidis of the tammar is lined by an epithelium composed of principal, mitochondria-rich, apical and basal cells, and intraepithelial leucocytes. The epithelium is structurally differentiated into 6 zones referred to as the initial segment, middle segment (3 subdivisions) and terminal segment (2 subdivisions). The occurrence of the initial, middle and terminal segments corresponds quite closely to the anatomical differentiation of the epididymis into a head, body and tail. The initial segment epithelium in the tammar is lower and has shorter and more slender stereocilia than in other mammals which have been described. Otherwise, the structure of the epithelium has similar characteristics in the tammar to that described in other mammals. Spermatozoa begin to develop the capacity for motility within the initial segment, but only show structural signs of maturation in the middle segment. The sperm head rotates through 90 degrees in the proximal subdivision of the middle segment. The cytoplasmic droplet is detached and spermatozoa develop the capacity for motility in the middle subdivision of the middle segment. The cytoplasmic droplets are phagocytosed by the epididymal epithelium of the middle segment. Sperm storage appears to be the main function of the terminal segment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00228437
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  • 71
    Digitale Medien
    Digitale Medien
    Ultrastructural immunocytochemical evidence for peptidergic neurotransmission in the pond snail Lymnaea stagnalis (1984)
    Springer
    Cell & tissue research 238 (1984), S. 197-201 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Peptidergic neurotransmission ; Lymnaea stagnalis ; Immunocytochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Three neuronal systems of the pond snail Lymnaea stagnalis were immunocytochemically investigated at the ultrastructural level with the unlabeled peroxidase-antiperoxidase technique. Preliminary electrophysiological and cell-filling investigations have shown that a cluster of neurons which reacts positively with an antiserum against the molluscan cardio-active peptide FMRFamide, sends axons to the penis retractor muscle. In this muscle anti-FMRF-amide (aFM) positive axons form neuro-muscular synapses with (smooth) muscle fibers. The morphological observations suggest the aFM immunoreactive system to be involved in peptidergic neurotransmission. In the right parietal ganglion a large neuron (LYAC) is penetrated by aFM positive axons which form synapse-like structures (SLS) with the LYAC. The assumption that the SLS represent the morphological basis for peptidergic transmission is sustained by the observation that iontophoretical application of synthetic FMRFamide depolarizes the LYAC. The axons of a group of pedal anti-vasopressin (aVP) positive cells run in close vicinity to the cerebral ovulation (neuro-)-hormone producing cell system (CDC system) Synapses or SLS between the two systems were not observed. The fact that (bath) application of arg-vasopressin induces bursting in the CDC, may indicate that the vasopressin-like substance of the aVP cells is released non-synaptically.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00215162
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  • 72
    Digitale Medien
    Digitale Medien
    Influence of photoperiod on the ultrastructure of the hypophysial pars tuberalis of the Djungarian hamster, Phodopus sungorus (1984)
    Springer
    Cell & tissue research 238 (1984), S. 213-216 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Photoperiods ; Pituitary gland, pars tuberalis ; Ultrastructure ; Phodopus sungorus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Conspicuous cytological differences are found between specific secretory cells of the hypophysial pars tuberalis of Djungarian hamsters exposed to long and short photoperiods. The cells differ with respect to the shapes of perikarya and nuclei and show diverse amounts of secretory granules, lysosome-like bodies and glycogen.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00215166
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  • 73
    Digitale Medien
    Digitale Medien
    Ultrastructure and immunolabeling of gonadotrops and thyrotrops in the pituitary of the African catfish, Clarias lazera (1984)
    Springer
    Cell & tissue research 238 (1984), S. 95-103 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Pituitary gland, pars anterior (distalis) ; Gonadotrops ; Thyrotrops ; Ultrastructure ; Immunolabeling ; Teleosts
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Pituitaries of the African catfish (Clarias lazera) were studied with immunocytochemical methods, at the light-microscopic and ultrastructural levels, for the characterization and localization of gonadotropic and thyrotropic cells. Two immunostaining procedures with the use of different markers were carried out: (i) with peroxidase-antiperoxidase, (ii) with protein A-gold. In routinely stained sections for light microscopy two types of basophils were identified in the proximal pars distalis: (1) large, round, purple cells, and (2) small, angular, light-blue cells. Both types were immunolabeled with antibodies against Clarias α,β-gonadotropin (GTH) and salmon G100-GTH. Only the large basophils were immunolabeled with anti-carp β-GTH, whereas the small basophils were the only cells immunolabeled with anti-human thyrotropin beta subunit (anti-h TSH-β). It was concluded that the large basophils represent the gonadotrops and the small basophils the thyrotrops. At the ultrastructural level the immunostaining of the GTH-cells was confined to three types of inclusions: (i) secretory vesicles, (ii) globules, and (iii) electron-dense, membrane-bound irregular masses. Especially the protein A- gold method, in combination with the use of a highly diluted homologous antiserum, resulted in a distinct localization of GTH. The presence of two types of nerve fibres, synaptically contacting the gonadotrops, is discussed with regard to the presence of a peptidergic (stimulatory) and an aminergic (inhibitory) control of GTH-secretion.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00215149
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  • 74
    Digitale Medien
    Digitale Medien
    Ultrastructural immunocytochemical demonstration of D2-protein in adrenal medulla (1984)
    Springer
    Cell & tissue research 238 (1984), S. 497-502 
    Details
    ISSN: 1432-0878
    Schlagwort(e): D2 glycoprotein ; Adrenal gland ; Immunocytochemistry ; Ultrastructure ; Cell adhesion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructural localization of the glycoprotein D2 in rat adrenal gland was investigated using immunohistochemical methods, and D2 localization in cultures of adult bovine chromaffin cells was studied by immunofluorescence. D2 was found to be situated on nerve fibers passing through the adrenal cortex and in the medulla zone, and also on the surface of all chromaffin cells. In addition, it was strongly expressed on the surface of glial (Schwann) cells. Cortical cells were unreactive to the antiserum. In cultures, all adrenalin and noradrenalin [dopamine-β-hydroxylase (DBH)-positive] cells were surface labelled for D2. A less frequent second cell type was recognized in vitro which was DBH negative but D2 positive. Such cells were presumed to be Schwann cells. These data are discussed in terms of the developmental origin of the cells and with regard to the putative functional rôle of D2 in cell adhesion phenomena.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219864
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  • 75
    Digitale Medien
    Digitale Medien
    The pineal gland of nocturnal mammals (1981)
    Springer
    Cell & tissue research 216 (1981), S. 253-271 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Pinealocytes ; Cell populations ; Bat ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In the pineal gland of the pipistrelle bat two different populations of pinealocytes and glial cells were observed electron microscopically. The pinealocytes of populations I and II differ in their content of metabolically active cell organelles. In the pinealocytes of population I, granular vesicles originating from the Golgi apparatus were found in the perikaryon and especially in the endings of the pinealocyte processes. Granular vesicles appeared to be more numerous in hibernating nulliparous females. The pinealocytes of population II are characterized by the presence of small cytoplasmic vacuoles, probably originating from cisternae of the granular endoplasmic reticulum and containing flocculent material of moderate electron density. The classification of the pinealocytes belonging to population II is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00233619
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  • 76
    Digitale Medien
    Digitale Medien
    The fine structure of the compound eye of the African armyworm moth, Spodoptera exempta walk. (Lepidoptera, Noctuidae) (1981)
    Springer
    Cell & tissue research 216 (1981), S. 333-347 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Insect eye ; Retina ; Ultrastructure ; Moth ; Spodoptera exempta
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The morphology of the compound eye of the noctuid moth Spodoptera exempta was investigated by electron microscopy. This eucone superposition eye is composed of about 8000 ommatidia. Each ommatidium is surrounded by six secondary pigment cells showing pigment movement according to the state of adaptation. It contains four crystalline cone cells forming together a crystalline cone and tract, two primary pigment cells, which encompass the crystalline cone, and usually eight retinula cells. On the basis of their rhabdomeric structure, three types of retinula cells can be distinguished. According to the structure of the rhabdom, two types of ommatidia are found in different regions of the eye. The rhabdom of the lobed type, providing more than 80% of ommatidia, is composed of V-shaped rhabdomeres with fanwise arranged microvilli. The rhabdom of the square type, found in a small area in the dorsal region of the eye, consists of triangular rhabdomeres with parallel microvilli. The functional significance of this difference is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00233623
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  • 77
    Digitale Medien
    Digitale Medien
    The lateral eyes of the scorpion, Androctonus australis (1980)
    Springer
    Cell & tissue research 206 (1980), S. 95-114 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Lateral eyes ; Scorpion ; Ultrastructure ; Retina ; Arhabdomeric cells
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The dioptric apparatus of the lateral eyes of the scorpion, Androctonus austrails, consists of a cuticular lens, but lacks a vitreous body. The retina is formed by (1) retinula cells displaying a contiguous network of rhabdoms; (2) arhabdomeric cells bearing a distal dendrite that contacts retinula cells via numerous projections and ends before the rhabdomere of the retinula cells; (3) pigment cells that ensheath retinula and arhabdomeric cells with the exception of the contact regions; and (4) neurosecretory fibres possibly originating in the supraesophageal ganglion. The ratio of the number of retinula to arhabdomeric cells is determined to be close to 2 ∶ 1 in the three larger anterolateral eyes, in contrast to the median eyes where the ratio is 5 ∶ 1. The construction of the dioptric apparatus as well as the anatomy of the retina imply that in the lateral eyes of Androctonus australis visual acuity is reduced. A certain degree of spatial discrimination, however, may be retained by the presence of a relatively high number of arhabdomeric cells. It is suggested that the lateral eyes of A. australis mainly function as light detectors, e.g., for Zeitgeber stimuli.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00233611
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  • 78
    Digitale Medien
    Digitale Medien
    Fine structure of the compound eyes and interfacetal mechanoreceptors of Cicindela tranquebarica Herbst (Coleoptera: Cicindelidae) (1980)
    Springer
    Cell & tissue research 206 (1980), S. 123-138 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Ultrastructure ; Sense organs ; Compound eyes ; Interfacetal mechanoreceptor ; Coleoptera
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The structure of the compound eyes of adult Cicindela tranquebarica Herbst was examined by use of light, scanning, and transmission electron microscopy. Each ommatidium of these photopic eyes is eucone and has a “subcorneal layer” situated between the corneal lens and crystalline cone. A distal rhabdomere consisting only of microvilli from retinula cell seven, a more proximal, rectangular, fused rhabdom formed from six retinula cells, and a basal, eighth retinula cell with a spherical rhabdomere comprise the light sensitive portions of the ommatidium. The “subcorneal layer” consists of lamellae of endocuticular microfibrils and, in surface view, shows 11 concave polygons. Proximal extensions of the crystalline thread form inter-retinular fibres containing microtubules between retinula cells 1/2, 3/4, 5/6, and 7/1. The primary pigment cells are devoid of pigment granules, but are rich in rough endoplasmic reticulum. Proximal to each retinula cell nucleus are two basal bodies, one perpendicular to the other. The more proximal basal body extends two fibrillar feet proximally which fuse to form a horizontally-banded ciliary rootlet extending the length of the retinula peripheral to the rhabdom. Each ommatidium is surrounded by 16 secondary pigment cells. Interfacetal mechanoreceptors between some adjacent lenses each have a single bipolar neuron, with a dendritic sheath, tubular body, cilium, outer and inner sheath cells, and an axon surrounded by a neurilemma sheath cell.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00233613
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  • 79
    Digitale Medien
    Digitale Medien
    Ontogeny and ultrastructure of somatostatin and calcitonin cells in the thyroid gland of the rat (1980)
    Springer
    Cell & tissue research 206 (1980), S. 193-201 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Somatostatin cells ; Calcitonin cells ; Ontogeny ; Ultrastructure ; Thyroid (rat)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Calcitonin cells are relatively numerous in the thyroid gland of the rat. In contrast, somatostatin cells are very scarce except at the time of birth and a few days thereafter, when they are conspicuously numerous. Somatostatin cells of the thyroid gland, which are ultrastructurally similar to somatostatin cells in gut and pancreas, also contain immunoreactive calcitonin. It is not clear whether somatostatin cells in the rat thyroid gland produce calcitonin or accumulate calcitonin from the environment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00232763
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  • 80
    Digitale Medien
    Digitale Medien
    Ultrastructural and gas-chromatographic analysis of the preputial glands of male nude (nu/nu) mice (1980)
    Springer
    Cell & tissue research 211 (1980), S. 73-82 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Preputial glands ; Nude mice ; Ultrastructure ; Gas chromatography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The preputial glands of male nude (nu/nu) mice were analyzed by a combination of electron microscopy and gas chromatography to determine whether or not they are affected, like developing hairs and nails, by the nu/nu genotype. Results of the analyses revealed no differences between the glands of nude and normal male mice in either their ultrastructural characteristics or lipid secretory products.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00233724
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  • 81
    Digitale Medien
    Digitale Medien
    Ultrastructural alterations associated with the initiation of follicular atresia (1980)
    Springer
    Cell & tissue research 211 (1980), S. 105-115 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Rat ; Preovulatory follicle ; Ultrastructure ; Degeneration ; Atresia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary To identify and describe ovarian follicles committed to undergo follicular degeneration (atresia), immature rats were primed with pregnant mare serum gonadotropin (PMSG). After PMSG treatment, preovulatory follicles develop but subsequently degenerate. Prior to the appearance of pyknotic nuclei (Stage I of atresia), degenerative changes were observed in focal areas of the granulosa cell layer. These changes include “blebbing” of the cytoplasm and alterations in the shape of the granulosa cells. The appearance of these degenerative changes coincides with a decrease in ovarian concentrations of estradiol and testosterone. Since estrogens and androgens maintain the follicle, the decline in estradiol and testosterone could be responsible for the further degenerative alterations that lead to complete deterioration of the preovulatory follicle. In Stage I atretic follicles, lysosome-derived autophagic vacuoles develop and macrophages invade both the thecal and granulosa cell layers. The combined actions of the autophagic vacuoles and macrophages could destroy both the granulosa-cell and thecal layers and thereby transform the preovulatory follicle into an ovarian cyst.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00233727
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  • 82
    Digitale Medien
    Digitale Medien
    A study by scanning (SEM) and transmission (TEM) electron microscopy of the glomerular capillaries in developing rat kidney (1980)
    Springer
    Cell & tissue research 212 (1980), S. 241-255 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Glomerulogenesis ; Glomerular capillaries ; Kidney development ; Corrosion casts ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Kidneys of 2 to 10 day-old rats of Wistar and Sprague-Dawley strains were fixed with glutaraldehyde by retrograde vascular perfusion and then prepared for observation in TEM and SEM. In addition methacrylate casts of differentiating glomerular capillaries were examined by SEM. Although the glomerular vascular pattern differs from one glomerulus to another, its differentiation proceeds according to the following general plan. First the glomerular capillary splits longitudinally, finally to form 3 to 5 lobules consisting of a capillary network, sustained centrally by the mesangium. In the present study the differentiation of glomerular capillaries is described in five successive arbitrarily selected stages. At Stage I a capillary loop penetrates between the lower limb and the middle segment of the S-shaped body, the rudimentary nephron. At Stage II the capillary undergoes a first subdivision, establishing the primitive lobulation of the glomerulus. At Stage III the vascular and urinary poles differentiate. At Stage IV the glomerulus assumes the aspect of a spherical body, and the capillaries in each lobule undergo subdivision. In Stage V the glomerular vascular pattern approaches its adult appearance, although the maturation processes continue for an extended period of time. Hence in the 10 day-old rat the best-differentiated glomeruli are half the size of adult glomeruli, and their capillary loops are proportionally less well-developed. The capillaries of adjacent lobules may communicate with each other, but a direct vascular shunt between the afferent and efferent vessels cannot be demonstrated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00233959
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  • 83
    Digitale Medien
    Digitale Medien
    Evidence for two secretory cell types in the Stannius bodies of the teleosts Fundulus heteroclitus and Carassius auratus (1980)
    Springer
    Cell & tissue research 212 (1980), S. 295-306 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Stannius bodies ; Secretory cell types ; Teleosts (Fundulus, Carassius) ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The Stannius bodies of killifish and goldfish were ultrastructurally investigated after exposure of the fish to media of different osmolality and calcium content. In both species two structurally different secretory cell types are found. Type-1 cells predominate. They contain an extensive granular endoplasmic reticulum, some large Golgi areas, and secretory granules with a mean diameter of about 0.4 μm. These cells are activated by transfer of freshwater fish to seawater, but not by transfer to low-calcium seawater. Type-2 cells often contain cytoplasmic processes that penetrate between the type-1 cells and are ending on the basal lamina. In this contact area granule release takes place. Type-2 cells contain some strands of granular endoplasmic reticulum, several small Golgi areas, and secretory granules with a mean diameter between 0.15 and 0.20 μm. Type-2 cells are not activated after transfer of fish to seawater. In killifish seawater exposure leads to a reduction of type-2 cells. The differences between the reactions of both cell types to different media point to functional differences between their secretory products. Type-1 cells may produce a hypocalcemic factor. It is concluded that type-2 cells are typical for freshwater fish or euryhaline fish spending part of their life cycle in freshwater. The proper function of these cells is unclear.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00233962
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  • 84
    Digitale Medien
    Digitale Medien
    The occurrence of erythropoiesis in the thymus of the bank vole (Clethrionomys glareolus) (1980)
    Springer
    Cell & tissue research 212 (1980), S. 307-314 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Thymus (Mammalia) ; Erythropoiesis ; Macrocytes ; Anaemia ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The thymus of wild young and adult bank voles (Clethrionomys glareolus) was examined by histological methods for the presence of developing erythroid cells. Nucleated erythroid cells were observed in 26% of the glands examined by light microscopy and in 69% of the glands examined by electron microscopy. The largest number of developing erythroid cells was observed in the thymus of pregnant females, also showing raised reticulocyte counts (3.1–10.2%). However, erythropoiesis could also be found in breeding and non-breeding, first year and older animals. Erythroid cells were mainly located in the cortex, sometimes in small groups interspersed between lymphoid cells, and also randomly scattered in the cortex. Occasionally, macrocytic erythroid cells were also present. Pyknotic cells were commonly present, and granulopoiesis was frequently observed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00233963
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  • 85
    Digitale Medien
    Digitale Medien
    Ultrastructure of catecholamine-containing axons in the intestine of the domestic fowl (1983)
    Springer
    Cell & tissue research 234 (1983), S. 411-425 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Intestines (chicken) ; Innervation ; Catecholamines ; Adrenergic fibres ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Axons in the duodenum, ileum and rectum of the domestic fowl were identified as catecholamine-containing (CA) on the basis of positive reactivity following chromaffin fixation for electron microscopy. CA-axons in association with blood vessels in all regions of the intestine and in non-vascular sites in the small intestine had a ‘ typical’ adrenergic appearance, in that they contained many small granular vesicles (SGV) and variable numbers of large granular vesicles (LGV). In the rectum the non-vascular CA-axon profiles were atypical, in that there were many elongated LGV and few SGV, and the chromaffin reactivity was weak. The nerve profiles in the rectum were dramatically reduced following 6-hydroxydopamine and reserpine treatment and were absent in rectum cultured in the absence of extrinsic ganglia. It was concluded that the profiles, in spite of their low chromaffin reactivity, truely represent CA-axons. The possibility was raised that the atypical morphology and reduced chromaffin reactivity is due to the presence of adrenaline.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00213778
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  • 86
    Digitale Medien
    Digitale Medien
    Ultrastructural identification of corticotropes of the fetal rat (1983)
    Springer
    Cell & tissue research 234 (1983), S. 427-437 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Corticotropes ; Rat fetus ; Ultrastructure ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Corticotropes of rat fetuses aged 16, 18 and 21 days were localized by the indirect antibody-enzyme method on semithin sections of the pituitary. The development of the ultrastructure of these cells was observed on consecutive ultrathin sections. In comparison with previous data our present results show that identification of a fetal cell type cannot be based entirely on morphological criteria. The structural peculiarities of corticotropes obtained from studies in vivo are compared with those observed in cells maintained in vitro.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00213779
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  • 87
    Digitale Medien
    Digitale Medien
    Cyclophosphamide-induced changes in rodent odontogenesis (1983)
    Springer
    Cell & tissue research 234 (1983), S. 679-689 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Odontogenesis ; Rats ; Cyclophosphamide ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Cyclophosphamide-induced changes in rodent odontogenesis were investigated by light and electron microscopy in four-day-old Sprague Dawley rats given one injection of 40 mg/kg of body weight of cyclophosphamide and killed at intervals of one hour, one day, one week and two weeks. Incisor and molar teeth were dissected from the animals, fixed in 2.0% glutaraldehyde in 0.1 M sodium cacodylate with 3.4% sucrose, and subsequently some were incubated for alkaline phosphatase reaction, and embedded in Spurr's medium for sectioning at light- and electron-microscopic levels. From three days a cell-sparse zone was created in the pulp in the growing end of the tooth and progressive cellular changes were observed which became more severe in the one-week and two-week specimens. Subodontoblast and adjacent pulpal cells were the most affected showing nuclear changes, damage to, or loss of, organelles, and inclusion bodies. Odontogenic epithelium was less affected and odontoblasts appeared to be unaffected by the drug. A new irregular matrix was laid down in the defect area and seemed to be the product of depolarized odontoblasts. This new matrix showed alkaline phosphatase activity, as did the cells embedded in it, and later it became mineralized. It is speculated that the polarity of odontoblasts might be maintained by an intact subodontoblastic layer; when this is lost the odontoblasts become depolarized and capable of secreting matrix from both ends.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00218659
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  • 88
    Digitale Medien
    Digitale Medien
    The spatial organization of nucleolar DNA in phytohemagglutinin-stimulated lymphocytes of the guinea pig (1984)
    Springer
    Cell & tissue research 235 (1984), S. 65-70 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Lymphocytes ; Phytohemagglutinin stimulation ; Nucleolar organizer region ; Three-dimensional reconstruction ; Ultrastructure ; Guinea pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructural changes in the spatial organization of nucleolar DNA in lymphocytes during phytohemagglutinin (PHA) stimulation was studied in guinea pigs by means of oxidized diaminobenzidine (DAB) at low pH as a differentially contrasting stain for nucleic acids and by the use of reconstruction of serial sections. The extended DNA filaments situated inside the fibrillar area originate from a large aggregation of heterochromatin, which is closely associated with the nucleolus, and from the perinucleolar shell of condensed chromatin. It is suggested that these two distinct regions of chromatin might be associated with different functions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00213724
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  • 89
    Digitale Medien
    Digitale Medien
    Diurnal variations in myeloid bodies of the newt retinal pigment epithelium (1984)
    Springer
    Cell & tissue research 235 (1984), S. 177-186 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Retinal pigment epithelium ; Myeloid bodies ; Diurnal variation ; Morphometrics ; Ultrastructure ; Lipid metabolism ; Endoplasmic reticulum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Myeloid bodies (MBs) occur in the newt (Notophthalmus viridescens) retinal pigment epithelium (RPE) and are similar to areas of specialized endoplasmic reticulum found in a variety of other cell types. The function of these structures is unknown, although a role in lipid metabolism has been strongly suggested. Random samples from conventionally-fixed and sectioned newt RPE, obtained over a 24-hr cycle (LD 12∶12), were examined by electron microscopy. Myeloid bodies appear as stacks of flattened endoplasmic reticulum-associated saccules which increase in length and number as the RPE accumulates shed outer segment material, prior to increase in the amount of stored lipid. Associations of MBs with the nuclear envelope can be related to this increased length. Myeloid bodies decrease numerically in the cell as phagosomes are removed from the cytoplasm, but a decrease in mean sectional MB area, seen in the light phase, is counteracted in darkness where individual MBs are larger than those found in the light. The total sectional area of MBs within a cell and their mean length varied depending on the lighting condition; differences were also found between eyes after extended periods of continuous light and dark. Ribosomes were found in association with the surfaces of both flattened and circular MBs, but they were consistently more densely associated with the shorter concave surfaces of curved regions. A new hypothesis for MB function is presented, which is concerned with their role in isolating toxic lipids such as retinoids, which are accumulated during phagocytosis of shed outer segment tips, and which are capable of disrupting membrane-bound systems necessary for their eventual metabolism and safe storage.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00213738
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  • 90
    Digitale Medien
    Digitale Medien
    Plasma cells in adult Atlantic hagfish, Myxine glutinosa (1984)
    Springer
    Cell & tissue research 235 (1984), S. 691-693 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Plasma cells ; Ultrastructure ; Immunology ; Myxinoids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Hagfishes, the most primitive vertebrates, are of special interest for the evolution of immune responses. Eptatretus stoutii, the Pacific hagfish, is able to mount cellular and humoral immune responses but all attempts to demonstrate in them the presence of plasma cells have failed. In the present study we demonstrate for the first time plasma cells identifiable by ultrastructural criteria in the pronephros, a primitive lymphohaemopoietic organ, of Myxine glutinosa, the Atlantic hagfish.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00226970
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  • 91
    Digitale Medien
    Digitale Medien
    A tubular configuration of the granular endoplasmic reticulum forming a raft-like parallel array in the pinealocytes of two species of Japanese moles (Mogera kobeae and M. wogura) (1984)
    Springer
    Cell & tissue research 236 (1984), S. 15-18 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Granular endoplasmic reticulum ; Ultrastructure ; Pinealocyte ; Mole
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Ten or more straight tubules, each of which consists of a double unit membrane of granular endoplasmic reticulum with a cylindrical profile, are joined side by side in a raft-like configuration in the cytoplasm of the pinealocytes of Japanese moles. They measure about 60 nm and 100 nm in their inner and outer diameters, respectively, and are often partially connected to unspecialized granular endoplasmic reticulum. Cisterns held between the inner and outer unit membranes with cylindrical profiles vary from 15 nm to 30 nm in width. Ensheathed portions of the cytoplasm are contiguous with cytoplasm outside the tubular units. The inner unit membranes of the tubules bear fewer ribosomal particles than the outer ones.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00216507
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  • 92
    Digitale Medien
    Digitale Medien
    Satellite cells in the tail muscles of the urodelan larvae during development (1984)
    Springer
    Cell & tissue research 236 (1984), S. 431-438 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Satellite cells ; Satellite fibres ; Tail muscle ; Urodela ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The incidence and ultrastructure of satellite cells in the tail muscles of urodelan larvae were examined during development during which the number of satellite cells is gradually reduced. They are found more frequently in red than in the white fibres in all four stages examined (stage 53, 64, 66+ and juvenile). As development proceeds, intercellular space between satellite cell and muscle fibre is in general gradually extended and is mostly filled with basal lamina. Small muscle cells, satellite fibres, which are situated under the basal lamina of the parent fibre, are morphologically similar to satellite cells but contain a small amount of myofibrils. Three types of satellite fibres are distinguishable on the basis of differences in K2-EDTA-treated ATPase activity, width of Z line, and parent fibre type. Neuromuscular junctions are visible in satellite fibres.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00214247
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  • 93
    Digitale Medien
    Digitale Medien
    Morphometric analysis of loading-induced changes in collagen-fibril populations in young tendons (1984)
    Springer
    Cell & tissue research 236 (1984), S. 465-470 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Tendon ; Collagen fibrils ; Morphometry ; Ultrastructure ; Loading ; Mouse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary This study was designed to gain more detailed morphological information on skeletal tendons in the course of adaptation to physical loading. The effect on collagen fibrils was investigated in 6-week-old mice by means of electron microscopy. Physical loading was performed on a treadmill 5 days a week for 1, 3, 5, 7 and 10 weeks. Morphometric analysis of collagen fibrils revealed the mean diameter, the diameter distribution, the number and the cross-sectional area. The principal observations included: 1. After one week of physical loading an increase in mean fibril diameter (30%, p≦0.01), in number (15%, p≦ 0.05), and in cross-sectional area (15%, p≦0.05), as well as a change in mean fibril diameter distribution. 2. From the third to the seventh week a fall under the level of the controls in mean diameter (26%, p≦0.01), in number (26%, p≦0.01), and a reduced cross-sectional area (17%, p≦0.01), accompanied by signs of splitting of individual collagen fibrils. 3. In the long-term study an increase in fibril number (29%, p≦0.01), a fall in mean diameter from 189 nm in the controls to 179 nm (p≦0.05) but no statistically significant change in the relative cross-sectional area (32%) per unit in comparison to unloaded tendons. The possible physiological implications of the findings are discussed in the light of several regulatory mechanisms known to appear during the course of physical loading in connective tissues.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00214251
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  • 94
    Digitale Medien
    Digitale Medien
    Changes in metabolism and hepatic ultrastructure induced by estradiol and testosterone in immature female Epinephelus akaara (Teleostei, Serranidae) (1984)
    Springer
    Cell & tissue research 236 (1984), S. 651-659 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Steroids ; Vitellogenesis ; Metabolism ; Ultrastructure ; Teleosts
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Estradiol injections increase serum level of calcium, amino acid, glucose, protein, ammonia and creatinine in immature Epinephelus akaara, and also increase levels of total lipid, cholesterol, phospholipid and esterified fatty acids. Hepatic protein, glycogen and lipid concentrations also rise after estradiol treatment, and some hepatic enzymes participating in the metabolism of nitrogen, lipid and carbohydrate, show increased activity. Serum vitellogenin levels are increased. Testosterone treatment increases serum protein, total lipid, cholesterol, amino acid and ammonia levels, and also hepatic glycogen content, but in contrast to estradiol treatment, testosterone does not change serum vitellogenin, glucose, calcium, phospholipid, esterified fatty acid and creatinine levels, nor the hepatic lipid and protein content. A small number of hepatic enzymes shows an increased activity. Vitellogenic fish show biochemical changes similar to that of estradiol-treated fish, but are different from those of immature fish. Estradiol treatment induces ultrastructural changes in the hepatocytes of immature fish that are similar to those found in vitellogenic fish. These include a proliferation of rough endoplasmic reticulum and Golgi apparatus, and an increase in glycogen and lipid, all indicative of enhanced metabolic activity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00217235
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  • 95
    Digitale Medien
    Digitale Medien
    Synaptic organization of a multifunctional interneuron in the central nervous system of Helix pomatia L. (1984)
    Springer
    Cell & tissue research 236 (1984), S. 677-683 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Interneuron ; Synaptology ; Ultrastructure ; Horseradish peroxidase ; Helix pomatia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The morphology, axonal arborization and ultrastructure of synaptic connections of the V21 giant neuron in the visceral ganglion of the snail Helix pomatia has been investigated following intracellular labelling with horseradish peroxidase. The V21 neuron establishes several afferent and efferent axo-axonic connections, mainly along the first half of the primary axon. Collaterals of 200–300 μm length originate from the primary axon, which shows further arborization, and both afferent and efferent synaptic contacts are formed on these fine axon profiles. Afferent and efferent contacts of the cell occur within very short distances of a few micrometers. On the basis of ultrastructure and vesicle and granule content, several afferent terminals can be distinguished on V21 labelled axon profiles. The majority of these afferent terminals resembles peptidergic-(neurosecretory)-like terminals. This finding supports the possible transmitter role of neuropeptides in the central nervous system of gastropods. Our results are consistent with and provide morphological evidence for recent electrophysiological observations suggesting that, in addition to integrating input, the V21 neuron functions as an interneuron in Helix central nervous system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00217238
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  • 96
    Digitale Medien
    Digitale Medien
    Interactions between immature porcine Leydig and Sertoli cells in vitro (1984)
    Springer
    Cell & tissue research 237 (1984), S. 357-362 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Leydig-Sertoli cell interaction ; FSH stimulation ; Ultrastructure ; Pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Interactions between Leydig and Sertoli cells, as well as a stimulatory effect of FSH on Leydig cell activity, have been reported in many studies. In order to investigate these interactions, the ultrastructure of immature pig Leydig cells under different culture conditions has been studied. When cultured alone in a chemically defined medium, there is a marked regression of the Leydig cell smooth endoplasmic reticulum and a swelling of the mitochondria. Addition of FSH or hCG does not prevent these phenomena. Co-culturing of Leydig cells with Sertoli cells from the same animal maintains the smooth endoplasmic reticulum at the level seen in vivo and in freshly isolated Leydig cells. The addition of FSH to the co-culture stimulates its development and increases Leydig cell activity, as assessed by an increase in hCG binding sites and an increased steroidogenic response to hCG. These results suggest that Sertoli cells exert a trophic effect on Leydig cells, and that the stimulatory effect of FSH on Leydig cell function is mediated via the Sertoli cells. These results reinforce the concept of a local regulatory control of Leydig cell steroidogenesis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00217157
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  • 97
    Digitale Medien
    Digitale Medien
    Restoration of fast muscle characteristics following cessation of chronic stimulation (1984)
    Springer
    Cell & tissue research 238 (1984), S. 221-230 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Fiber type ; Ultrastructure ; Stereology ; Stimulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary When fast-twitch skeletal muscles of the adult rabbit are subjected to continuous low-frequency activity by electrical stimulation of the corresponding motor nerves, the fibers undergo an ultrastructural transformation, so that after 6 weeks they have acquired an appearance typical of slow-twitch fibers. In the present study, stimulation was discontinued at this stage in order to follow the reverse transformation, in which the fibers recovered their original morphological characteristics under conditions of normal endogenous activity. Stereological techniques were used to assess the time course of this process over a period of 20 weeks in terms of fiber cross-sectional area, extent of T-system, thickness of the Z-band, and volume fraction of mitochondria in the fiber core. Fibers of transformed muscles were smaller than those of control muscles, but the differences were no longer evident after 9 weeks of recovery. After 2 weeks the T-system was still of limited extent, as is characteristic of slow-twitch fibers; it increased toward the amount typical of fast-twitch fibers between 2 and 4 weeks, and had reached its full extent by 12 weeks. The wide Z-bands characteristic of slow-twitch fibers were retained for 4 weeks, but the thickness had begun to decrease by 8 weeks and recovery was complete by 12 weeks. The mitochondrial volume did not increase during recovery, in contrast to the large increases which had been observed to take place between 2 and 6 weeks during the fast-to-slow transformation. Overall, the recovery of fast-twitch ultrastructural characteristics was complete, but followed a more extended time course, and involved less myofibrillar disruption at an intermediate stage, than the original fast-to-slow transformation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00217292
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  • 98
    Digitale Medien
    Digitale Medien
    Development and ultrastructural autoradiographic studies of nucleolus-like bodies (nuages) in oocytes of a viviparous teleost (Xiphophorus helleri) (1984)
    Springer
    Cell & tissue research 238 (1984), S. 121-128 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Ultrastructure ; Autoradiography ; Oocytes ; Nucleolus-like bodies ; Teleost
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Cytoplasmic granulo-fibrillar masses, usually termed nucleolus-like bodies (NLB) or nuages, have been described in several different cell types. They are sometimes associated with a mitochondrial arrangement, this association often being marked during certain phases of the oocyte cycle. In Xiphophorus helleri, NLB consist of fibrillar and granular material that gradually becomes more granular during meiotic prophase I, and is associated with mitochondrial arrangements during diplotene and dictyate of meiosis. Autoradiographic studies of uridine incorporation into the nucleolus and subsequently into NLB suggest that the latter represent a reserve of ribonucleoproteins that is later used in ribosomal maturation during vitellogenesis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00215152
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  • 99
    Digitale Medien
    Digitale Medien
    Ultrastructure of the eyes of the grass shrimp, Palaemonetes pugio (1984)
    Springer
    Cell & tissue research 238 (1984), S. 271-288 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Compound eye ; Ultrastructure ; Grass shrimp, Palaemonetes pugio ; Light adaptation ; Dark adaptation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The cone cells and corneagenous cells possess extensive networks of smooth tubular endoplasmic reticulum that may be involved in optical reflectance and light-adaptational responses, respectively. The extracellular basal lamina of the basement membrane is confluent with glial cell capillary walls and may prove to be a viaduct for the transmission of hemolymph-borne substances to the retina or of retinal degradation products to the hemolymph. In addition to dense pigment granules, the distal pigment cells are shown for the first time to contain migratory reflecting platelets that are usually polymorphic in light-adapted eyes but are rectangular in dark-adapted eyes. In the latter these plates become aligned against the crystalline cones and presumably contribute to the reflection superposition optics of the grass shrimp. Dark-adapted retinular cells possess well-developed perirhabdomal cisternae, oblong or ovoid mitochondria, generally vesicular rough endoplasmic reticulum, and occasional, spherical, calcium-like intrarhabdomal inclusions. Light-adapted retinular cells possess poorly developed perirhabdomal cisternae, lamelliform rough endoplasmic reticulum, and condensed mitochondria frequently associated with lipid droplets and pigment granules. The cytoplasmic boundaries of the reflecting pigment cells expand into the extracellular spaces between individual ommatidial retinular cells during dark adaptation and recede to the interommatidial extracellular spaces during light adaptation. Cytoplasmic microfilament bundles found only at the bases of partially light-adapted rhabdomeric microvilli may be involved in microvillar shortening.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00217299
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  • 100
    Digitale Medien
    Digitale Medien
    Ultrastructural studies of severed medial giant and other CNS axons in crayfish (1980)
    Springer
    Cell & tissue research 208 (1980), S. 123-133 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Lesioned axons ; Ultrastructure ; Crayfish
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distal stumps of severed medial giant axons (MGAs) and of non-giant axons (NGAs) in the CNS of the crayfish Procambarus clarkii show long-term (5–9 months) survival associated with disorientation of mitochondria and thickening of the glial sheath. However, the morphological responses of the two axonal types differ in that neither the proximal nor the distal stump of severed MGAs ever fills with mitochondria as is observed in some severed NGAs. Furthermore, the adaxonal glial layer never completely encircles portions of MGA axoplasm as occurs in many severed NGAs; in fact, ultrastructural changes in the adaxonal layer around severed MGAs are often difficult to detect. No multiple axonal profiles are ever seen within the glial sheath of the proximal or distal stumps of severed MGAs whereas these structures are easily located within severed NGAs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234178
    Standort Signatur Erwartet Verfügbarkeit
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