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  • Angiosperms  (77)
  • Lepidoptera  (57)
  • Immunocytochemistry  (44)
  • Seismology
  • Ultrastructure
  • Springer  (200)
  • Dar Al Ummah, Abu Dhabi
  • Division of Earthsciences, Seismological Laboratory, California Institute of Technology
  • Dover Publ.
  • 2010-2014
  • 1990-1994  (200)
  • 1980-1984
  • 1991  (200)
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  • 1
    Digitale Medien
    Digitale Medien
    A sex attractant for male Swammerdamia pyrella (1991)
    Springer
    Entomologia experimentalis et applicata 61 (1991), S. 95-96 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Swammerdamia pyrella ; Lepidoptera ; Yponomeutidae ; (Z)-5-tetradecenyl acetate ; (Z)-7-tetradecenyl acetate ; sex attractant ; field trapping
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00367173
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  • 2
    Digitale Medien
    Digitale Medien
    Role of bilateral chemosensory input in food discrimination by Manduca sexta larvae (1991)
    Springer
    Entomologia experimentalis et applicata 61 (1991), S. 159-168 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Feeding ; behaviour ; chemosensory ablation ; Manduca sexta ; Lepidoptera ; bilateral sensory input ; input redundancy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The function of bilateral chemosensory input in food discrimination was examined using larvae of the tobacco hornworm, Manduca sexta (Johan.) (Lepidoptera: Sphingidae), in 2-choice preference tests. Larvae having three different complements of chemosensory organs remaining after microsurgery were tested: unoperated, unilaterally-ablated, and bilaterally-ablated. Discrimination between Solanum pseudocapsicum (L.) and Pelargonium hortorum (Bailey) was reduced after unilateral removal of chemosensory organs. A similar effect was found in tests offering larvae a choice between one plant species or an ethanolic extract of S. pseudocapsicum and wetted filter paper, indicating an impaired food detection. These results demonstrate that both sets of chemosensory organs are required for normal feeding decisions about these plants. Six additional plant species were each tested against wetted filter paper. The function of bilateral chemosensory input in food discrimination varies with the plant species tested. Bilateral chemosensory input is required for discrimination of Vigna sinensis (Savi) and Raphanus sativus (L.), but not for that of Lycopersicon esculentum (Mill.), Datura innoxia (L.), Brassica napus (L.), and Canna generalis (Bailey). Discrimination of V. sinensis, S. pseudocapsicum, and P. hortorum by unoperated larvae is twice as strong as that by unilaterally-ablated larvae, suggesting algebraic addition of unilateral sensory inputs. For R. sativus unilateral input does not mediate discrimination, but bilateral input does, indicating sensory processing which may be more than additive. These results show that information mediated by bilateral chemosensory organs of M. sexta is not redundant in mediating feeding decisions, but provide the necessary sensory input for normal discrimination. This suggests that, for some plant species, feeding decisions are based on both qualitative and quantitative aspects of chemosensory input. No difference in preferences between left-sided and right-sided operated larvae were observed which suggests functional duplication of each set of unilateral chemosensory organs. Possible neural mechanisms underlying feeding decisions mediated by bilateral versus unilateral chemosensory inputs are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00191746
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  • 3
    Digitale Medien
    Digitale Medien
    Leaf shelter-building caterpillars harness forces generated by axial retraction of stretched and wetted silk (1991)
    Springer
    Journal of insect behavior 4 (1991), S. 21-32 
    Details
    ISSN: 1572-8889
    Schlagwort(e): leaf shelter-building ; silk ; Lepidoptera ; caterpillar ; leaf-roller ; leaf-tier ; leaf-folder
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Leaf shelter-building caterpillars generate most of the force required to pull leaf surfaces together by stretching silk strands while spinning. Axially retractive forces produced by columns of stretched strands enabled caterpillars in our study to generate forces as great as 0.3 Newtons (i.e., a 30-g force). We found that caterpillar silk also contracts instantly when wetted, producing an additional, though smaller, axially retractive force. Contraction ratios (final length/ original length) of the wetted silk of 19 species ranged from 0.21 to 0.93 and were smallest among species that use their silk to make leaf shelters. Our study, the first to identify the specific sources of the energy harnessed by caterpillars to tie, roll, or fold leaves, indicates that silk properties and caterpillar behavior have coevolved to facilitate the leaf shelter-building process.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01092548
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  • 4
    Digitale Medien
    Digitale Medien
    Sex pheromones of Spilonota ocellana and Spilonota laricana (1991)
    Springer
    Entomologia experimentalis et applicata 60 (1991), S. 219-223 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Spilonota ocellana D. & S. ; Spilonota laricana Hein. ; Lepidoptera ; Tortricidae ; sex pheromone ; (Z)-8-tetradecenyl acetate ; (Z)-8-tetradecen-1-ol ; sibling species ; reproductive isolation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The sex pheromones of Spilonota ocellana D. & S. and Spilonota laricana Hein. (Lepidoptera: Tortricidae) were identified by chemical analysis and field trapping. Female moths of the two species produce (Z)-8-tetradecenyl acetate, (Z)-8-tetradecen-1-ol and dodecyl acetate in almost the same proportions (98:1:1 and 97:3:1). Males of both species were best attracted to a blend of 10:1 to 1:1 Z8-14Ac:Z8-14OH. This indicates that mating barriers other than sex pheromones exist between sympatric populations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00354214
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  • 5
    Digitale Medien
    Digitale Medien
    Field tests of (E,Z)-3,13-octadecadien-1-ol acetate: a sex attractant synergist for male currant borer, Synanthedon tipuliformis (1991)
    Springer
    Entomologia experimentalis et applicata 60 (1991), S. 283-288 
    Details
    ISSN: 1570-7458
    Schlagwort(e): (E,Z)-2,13-octadecadien-1-ol acetate ; (E,Z)-3,13-octadecadien-1-ol acetate ; Synanthedon tipuliformis ; Sesiidae ; Lepidoptera ; field trapping ; sex attractant ; geographical differences ; Belgium ; Bulgaria ; Denmark ; GDR ; Hungary ; Italy ; Lithuania ; Norway ; Soviet Union ; Switzerland ; United Kingdom
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00354221
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  • 6
    Digitale Medien
    Digitale Medien
    Behavioral changes and growth inhibition in last instar larvae of Heliothis zea induced by oral and topical application of precocene II (1991)
    Springer
    Entomologia experimentalis et applicata 59 (1991), S. 207-217 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Insect behavior ; Heliothis zea ; Lepidoptera ; Noctuidae ; precocene II ; methylenedioxy-precocene ; toxicity ; growth inhibition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In diet choice tests, newly-ecdysed fifth instar Heliothis zea larvae randomly chose diet containing 4 mM precocene II or diet without precocene II but initially preferred to feed on diet without precocene II. After two days, however, they were found more frequently on diet containing precocene II. Nevertheless, larval growth and development were inhibited when forced to eat diet containing precocene II. Removal of the maxillae, the site of the primary gustatory receptors, did not prevent the growth inhibition caused by larval consumption of diet with precocene II. Topical treatments with precocene II also caused larval growth inhibition, and daily treatments were more detrimental to the larvae than a large single dose. Addition of methylenedioxyprecocene (6,7-methylenedioxy-2,2-dimethylchromene) to the diet did not reverse the observed larval growth inhibition and this compound was itself significantly toxic. These results indicate that larval growth and development are disrupted after precocene II ingestion, but not because of preingestive discrimination by olfaction and gustation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00189363
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  • 7
    Digitale Medien
    Digitale Medien
    Food acceptance by a monophagous and an oligophagous insect in relation to seasonal changes in host plant suitability (1991)
    Springer
    Entomologia experimentalis et applicata 59 (1991), S. 111-122 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Yponomeuta evonymellus ; Yponomeuta padellus ; Prunus padus ; Crataegus monogyna ; Lepidoptera ; monophagous ; oligophagous ; host-plants ; food-acceptance ; seasonal changes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Food acceptance by larvae of two lepidopteran species feeding on Rosaceae, viz. Yponomeuta evonymellus (monophagous) and Y. padellus (oligophagous), was compared. The influence of seasonal changes in plants as food for both insects was examined, in particular, the effects of nitrogen and sorbitol in leaves. In the laboratory, Y. evonymellus accepts Crataegus monogyna, a host plant of Y. padellus, and Y. padellus accepts Prunus padus, the host plant of Y. evonymellus. P. padus is the most suitable food plant for Y. evonymellus. No difference in food-quality for Y. padellus was found between C. monogyna and P. padus. The performance of both species on P. padus is less influenced by seasonal changes than on Crataegus. The suitability of Crataegus decreases during the season. This is probably caused by the decrease of its nitrogen content, and not by the decrease of sorbitol in the plant. The monophagous, Y. evonymellus, is more sensitive to seasonal changes in its food when fed with a non host plant than the oligophagous Y. padellus. In oviposition experiments both species have a preference for their normal host-plants.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00351956
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  • 8
    Digitale Medien
    Digitale Medien
    Changes in calling behaviour and mating success in the European corn borer (Ostrinia nubilalis), caused by relative humidity (1991)
    Springer
    Entomologia experimentalis et applicata 61 (1991), S. 131-138 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Calling ; mating ; relative humidity ; age ; reproduction ; Ostrinia nubilalis ; European corn borer ; Pyralidae ; Lepidoptera
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Nous avons étudié le comportement d'appel des femelles vierges d'Ostrinia nubilalis maintenues sous trois conditions constantes d'humidité relative, depuis l'émergence jusqu'à la sixième nuit d'appel, ainsi que l'incidence d'accouplement d'individus placés en milieu sec ou humide pour diverses périodes de temps. Les conditions d'humidité n'ont pas significativement affecté l'âge moyen auquel les femelles ont commencé à appeler au cours de leur vie, bien qu'il ait été plus variable à 53% h.r. Les nuits subséquentes, le comportement d'appel des femelles maintenues à basse humidité a débuté plus tard dans la nuit, s'est exprimé pour une période de temps plus courte avec moins de séquences d'appel que celui de leurs congénères placés en milieu humide, et la proportion de femelles en appel a toujours été plus faible à 53% h.r. Ces changements du comportement préreproducteur des femelles se sont répercutés sur l'incidence d'accouplement qui, les deux premiers jours suivant lémergence, a été significativement plus faible à basse humidité qu'elle ne l'a été en milieu humide. Ces résultats seront discutés en relation avec l'écologie de O. nubilalis et associés à sa susceptibilité à la dessication.
    Notizen: Abstract We examined the calling behaviour of O. nubilalis virgin females, held at three different constant conditions of relative humidity from the time of emergence through their sixth night of calling, as well as the incidence of mating over time at low or high relative humidity conditions. The mean age at which females initiated calling in their life was independent of relative humidity conditions, although more variable at low humidity. On successive nights of calling, fewer virgin European corn borer females called under low compared with high humidity conditions, and those that did began later in scotophase, had fewer calling bouts, and spent less time calling. These changes in the female prereproductive behaviour were reflected on the incidence of mating which, in the first two days following emergence, was significantly less at low than at high humidity conditions. The ecological significance of these results is discussed in relation with the susceptibility of O. nubilalis to desiccation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00191743
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  • 9
    Digitale Medien
    Digitale Medien
    Angiosperm origin and early stages of seed plant evolution deduced from rRNA sequence comparisons (1991)
    Springer
    Journal of molecular evolution 32 (1991), S. 253-261 
    Details
    ISSN: 1432-1432
    Schlagwort(e): Chloroplast 4.5S rRNA ; Cytosolic and chloroplast 5S rRNAs ; 5.8S rRNA ; 18S rRNA ; Nucleotide sequences ; Phylogenetic trees ; Angiosperms ; Gymnosperms ; Monocotyledons ; Dicotyledons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Complete or partial nucleotide sequences of five different rRNA species, coded by nuclear (18S, 5.8S, and 5S) or chloroplast genomes (5S, 4.5S) from a number of seed plants were determined. Based on the sequence data, the phylogenetic dendrograms were built by two methods, maximum parsimony and compatibility. The topologies of the trees for different rRNA species are not fully congruent, but they share some common features. It may be concluded that both gymnosperms and angiosperms are monophyletic groups. The data obtained suggest that the divergence of all the main groups of extant gymnosperms occurred after the branching off of the angiosperm lineage. As the time of divergence of at least some of these gymnosperm taxa is traceable back to the early Carboniferous, it may be concluded that the genealogical splitting of gymnosperm and angiosperm lineages occurred before this event, at least 360 million years ago, i.e., much earlier than the first angiosperm fossils were dated. Ancestral forms of angiosperms ought to be searched for among Progymnospermopsida. Genealogical relationships among gymnosperm taxa cannot be deduced unambiguously on the basis of rRNA data. The only inference may be that the taxon Gnetopsida is an artificial one, andGnetum andEphedra belong to quite different lineages of gymnosperms. As to the phylogenetic position of the two Angiospermae classes, extant monocotyledons seem to be a paraphyletic group located near the root of the angiosperm branch; it emerged at the earliest stages of angiosperm evolution. We may conclude that either monocotyledonous characters arose independently more than once in different groups of ancient Magnoliales or that monocotyledonous forms rather than dicotyledonous Magnoliales were the earliest angiosperms. Judging by the rRNA trees, Magnoliales are the most ancient group among dicotyledons. The most ancient lineage among monocotyledons leads to modern Liliaceae.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02342748
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  • 10
    Digitale Medien
    Digitale Medien
    Sex pheromones and their potential role in the evolution of reproductive isolation in small ermine moths (Yponomeutidae) (1991)
    Springer
    Chemoecology 2 (1991), S. 20-28 
    Details
    ISSN: 1423-0445
    Schlagwort(e): speciation ; reinforcement ; character displacement ; biosynthesis ; phylogeny ; sex pheromones ; reproductive isolation (Z)-11-tetradecenyl acetate ; (E)-11-tetradecenyl acetate ; Lepidoptera ; Yponomeutidae ; Yponomeuta
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Sex pheromone communication in the nine European species of small ermine moths (Yponomeuta) is reviewed in regard to the potential role of pheromones in the speciation process. Six of the nine species studied (viz.,Y. evonymellus, Y. cagnagellus, Y. padellus, Y. irrorellus, Y. plumbellus, andY. vigintipunctatus) use a mixture of (E)-11-and (Z)-11-tetradecenyl acetate in different ratios as primary pheromone components, with combinations of tetradecyl acetate, (Z)-9-tetradecenyl acetate, (Z)-11-hexadecenyl acetate and the corresponding alcohols of the acetates as additional pheromone components. Analysis of (Z)- to (E)-11-tetradecenyl acetate ratios produced by individual females of these species demonstrated significant variation among females of all species. However, the ranges of ratios produced byY. cagnagellus, Y. irrorellus, andY. plumbellus, sharing the same host-plant species, spindle tree, did not overlap. Niche separation of all six species mentioned required consideration of at least one additional pheromone component or of temporal aspects. The remaining three species,i.e. Y. malinellus, Y. mahalebellus andY. rorellus, have pheromones that differ qualitatively. Biosynthetic routes to the pheromone components identified are proposed on the basis of fatty acid pheromone precursors found in the pheromone glands. A phylogenetic tree for the genus is constructed based on allozyme frequency data and changes in pheromone composition are superimposed on this tree. We suggest that the ancestral ermine moth pheromone is a mixture of (Z)-11- and (E)-11-tetradecenyl acetate and the corresponding alcohols, and a scenario of how present-day patterns evolved is outlined. The pheromone differences among the three species using spindle tree as their host-plant might have evolved throughreproductive character displacement upon secondary contact between populations that had already diverged genetically in allopatry. Pheromone differences within the so-calledpadellus-complex (includingY. cagnagellus, Y. mahalebellus, Y. malinellus, Y. padellus, andY. rorellus) in which species might have originated sympatrically, may have evolved byreinforcing selection as these species still hybridise and produce viable offspring when confined in cages. The role of pheromones in reproductive isolation amongYponomeuta species is emphasised by (1) the function of pheromone components of some of the species as behavioural antagonists to other species, (2) the cross-attraction under experimental conditions between allochronic species with similar pheromones, and (3) the formation of hybrids in the laboratory between species that are isolated in nature by pheromone differences.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01240662
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  • 11
    Digitale Medien
    Digitale Medien
    Are accessory nuclei involved in the establishment of developmental gradients in hymenopteran oocytes? (1991)
    Springer
    Development genes and evolution 199 (1991), S. 423-426 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Oogenesis ; Accessory nuclei ; Developmental gradients ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary In the oocytes ofTenthredo olivacea, accessory nuclei (AN) are formed by budding from the nuclear envelope of the oocyte nucleus. Newly formed AN contain electron-dense material of nuclear origin and are surrounded by a double envelope devoid of pores. Such structures are subsequently transported to the peripheral ooplasm (periplasm), where they grow to reach a final diameter of 5 µm. In the envelopes of advanced AN nuclear pores arise. Through these pores “nuage” material is extruded into the surrounding periplasm. These findings are discussed with respect to a possible involvement of AN in the establishment of developmental gradients in hymenopteran oocytes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01705853
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  • 12
    Digitale Medien
    Digitale Medien
    Focus-of-attention techniques in the automatic interpretation of seismograms (1991)
    Springer
    Pure and applied geophysics 135 (1991), S. 61-75 
    Details
    ISSN: 1420-9136
    Schlagwort(e): Seismology ; seismic networks ; artificial intelligence ; expert systems ; automatic interpretation ; seismic event detection ; data compression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The focus-of-attention techniques implemented in SNA2, a knowledge-based system for seismogram interpretation, are presented. They consist of data compression of the input digital records, scanning of the compressed traces to detect candidate seismograms and extraction of seismogram features. A criterion is given to rate the clarity of seismograms; the clarity defines the order in which the system will consider them to build up the interpretation. The proposed techniques are simple and fast; they allow quick rejection of noise and focussing the attention of the system on the portions of traces containing relevant information.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00877009
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  • 13
    Digitale Medien
    Digitale Medien
    The origin of the nascent blastocoele in preimplantation mouse embryos ultrastructural cytochemistry and effect of chloroquine (1991)
    Springer
    Development genes and evolution 200 (1991), S. 77-85 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Lysosomes ; Ultrastructure ; Chloroquine ; Blastocyst ; Mouse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Mouse morulae are known to undergo cavitation as soon as some external cells have entered the sixth cell cycle (Garbutt et al. 1987). Since the early cytological features of cavitation are still unclear, we undertook a careful ultrastructural analysis of late morulae-nascent blastocysts. In addition, since maturation of lysosomes might be involved in the first step of cavity formation, we focused our attention on these organelles by means of the cytochemical localization of trimetaphosphatase activity and by the study of the effects of chloroquine on precavitation embryos. Our results suggest that cavitation starts in a few external cells (presumably competent cells entering the sixth cell cycle), by the chloroquine-sensitive formation of degradative autophagic vacuoles engulfing lipid droplets and vacuoles containing osmiophilic material. These complex structures enlarge (as a result of lipid metabolism?) and so transform into intrablastomeric cavities which, by means of a membrane fusion process, very rapidly become extracellular cavities that coalesce. The abembryonic pole of the blastocyst is determined in this way. Moreover, we suggest that the juxtacoelic cytoplasmic processes covering the inner cell mass (ICM) cells, which are known to restrict the expression of their totipotency during early cavitation (Fleming et al. 1984), are the latest remnants of the walls of the growing intrablastomeric cavities.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00637187
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  • 14
    Digitale Medien
    Digitale Medien
    Immunochemical similarities among the hemolymph juvenile hormone binding proteins of moths (1991)
    Springer
    Cellular and molecular life sciences 47 (1991), S. 945-948 
    Details
    ISSN: 1420-9071
    Schlagwort(e): Juvenile hormone ; Manduca sexta ; Lepidoptera ; immunotaxonomy ; monoclonal antibodies ; hemolymph
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The hemolymph from various species of moths was analyzed for cross-reactivity with a panel of six monoclonal antibodies made against the hemolymph juvenile hormone binding protein ofManduca sexta. With the exception of one antibody, the immunoreactivity was limited to the sphingid family. One monoclonal antibody cross-reacted with a number of lepidopteran species; however, families such as Noctuidae and Pyralidae, known to have high affinity, low molecular weight juvenile hormone binding proteins, did not cross-react. Immunological cross-reactivity withManduca sexta juvenile hormone binding protein in several primitive moth families supports the current model of phylogenetic relationships in the order Lepidoptera.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01929888
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  • 15
    Digitale Medien
    Digitale Medien
    Secretory tapetum of Brassica oleracea L.: polarity and ultrastructural features (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 28-35 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Tapetal cells ; Brassica oleracea L ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ultrastructure of the secretory, binucleate tapetum of Brassica oleracea in the micro spore mother cell (MMC) stage through to the mature pollen stage is reported. The tapetal cells differentiate as highly specialized cells whose development is involved in lipid accumulation in their final stage. They start breaking down just before anther dehiscence. Nuclei with dispersed chromatin, large nucleoli and many ribosomes in the cytoplasm characterize the tapetal cells. The wall-bearing tapetum phase ends at the tetrade stage. The dissolution of tapetal walls begins from the inner tangential wall oriented towards the loculus and proceeds gradually along the radial walls to the outer tangential one. The plasmodesmata transversing the radial walls between tapetal cells persist until the mature microspore, long after loss of the inner tangential wall. After wall dissolution, the tapetal protoplasts retain their integrity and position within the anther locule. The tapetal cell membrane is in direct contact with the exine of the microspores/pollen grains and forms tubular evaginations that increase its surface area and appear to be involved in the translocation of solutes from the tapetal cells to the microspores/ pollen grains. The tapetal cells exhibit a polarity expressed by spatial differentiation in the radial direction.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00194568
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  • 16
    Digitale Medien
    Digitale Medien
    Brassica napus pollen development during generative cell and sperm cell formation (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 176-181 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Pollen ; Brassica napus ; Mitoses ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Brassica napus pollen development during the formation of the generative cell and sperm cells is analysed with light and electron microscopy. The generative cell is formed as a small lenticular cell attached to the intine, as a result of the unequal first mitosis. After detaching itself from the intine, the generative cell becomes spherical, and its wall morphology changes. Simultaneously, the vegetative nucleus enlarges, becomes euchromatic and forms a large nucleolus. In addition, the cytoplasm of the vegetative cell develops a complex ultrastructure that is characterized by an extensive RER organized in stacks, numerous dictyosomes and Golgi vesicles and a large quantity of lipid bodies. Microbodies, which are present at the mature stage, are not yet formed. The generative cell undergoes an equal division which results in two spindle-shaped sperm cells. This cell division occurs through the concerted action of cell constriction and cell plate formation. The two sperm cells remain enveloped within one continuous vegetative plasma membrane. One sperm cell becomes anchored onto the vegetative nucleus by a long extension enclosed within a deep invagination of the vegetative nucleus. Plastid inheritance appears to be strictly maternal since the sperm cells do not contain plastids; plastids are excluded from the generative cell even in the first mitosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00190001
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  • 17
    Digitale Medien
    Digitale Medien
    Ultrastructure of the micropyle and its relationship to pollen tube growth and synergid degeneration in sunflower (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 166-175 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Helianthus annuus ; Ultrastructure ; Micropyle ; Pollen tube ; Synergid degeneration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Ultrastructural studies made on the micropyle of sunflower before and after pollination resulted in the following observations. (1) The micropyle is closed instead of a hole or canal. The inner epidermis of the integument on both sides of the micropyle is in close contact at the apex of the ovule. The boundary between the two sides consists of two layers of epidermal cuticle. (2) The micropyle contains a transmitting tissue. The micropyle is composed of an intercellular matrix produced by the epidermal cells of the integument. (3) The micropyle is asymmetrical, and is much wider on the side proximal to the funicle. On the funicle side the cells adjacent to the micropyle are similar to those of the transmitting tissue: they have large amounts of intercellular matrix and contain abundant dictyosomes, rough ER, and starch grains, and provide an appropriate environment for growth of the pollen tubes. The cells distal to the funicle are rich in rough ER and lipid bodies; they lack large intercellular spaces. (4) The micropyle is variable in the axial direction, i.e., it is much larger and more asymmetric at the level distal to the embryo sac than at a level close to the embryo sac. After pollination, one to four pollen tubes are seen in a micropyle. During their passage through the micropyle, most pollen tubes are restricted to the side proximal to the funicle. There is a greater tendency (81%) for the degenerate synergid to be located toward the funicle, i.e., at the same side as the pollen tube pathway. The data indicate a close relationship between micropyle organization, orientation of pollen tube growth, and synergid degeneration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00190000
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  • 18
    Digitale Medien
    Digitale Medien
    Sperm cells of the pollen tubes of Brassica: Ultrastructure and isolation (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 226-234 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Male germ unit ; Sperm cells ; Isolation ; Pollen tubes ; Brassica napus ; Pollen-tube inner plasma membrane ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Sperm cells of pollen tubes grown both in vivo and in vitro form a male germ unit. Extensions from both sperm cells of each pollen tube are closely associated with the tube nucleus. A high yield (2.7 × 104. 20 mg−1 pollen grains germinated) of intact sperm cells was obtained following release by osmotic shock from pollen tubes grown in vitro. Structural integrity of isolated sperm was maintained by isolation at low temperature in an osmotically balanced medium. At 4° C many isolated sperm pairs were still enclosed within the pollentube inner plasma membrane. Sperm cells not enclosed within this membrane no longer remained connected as a pair. During isolation vesicles formed on the sperm cell surface from disruption of the fibrillar components bridging the periplasmic space. Both in the pollen tube and after isolation the sperm nucleus is in close association with at least one region of the sperm plasma membrane. Sperm isolated at room temperature showed the presence of nucleopores, and nuclei were euchromatic, instead of heterochromatic as in intact sperm in the pollen tube.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00190009
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  • 19
    Digitale Medien
    Digitale Medien
    Microsporogenesis and tapetal development in fertile and cytoplasmic male-sterile sugar beet (Beta vulgaris L.) (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 215-225 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Cytoplasmic male sterility ; Beta vulgaris ; Microsporogenesis ; Tapetum ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The development of sporogenous and tapetal cells in the anthers of male-fertile and cytoplasmic male-sterile sugar beet (Beta vulgaris L.) plants was studied using light and transmission electron microscopy. In general, male-sterile anthers showed a much greater variability in developmental pattern than male-fertile anthers. The earliest deviation from normal anther development was observed to occur in sterile anthers at meiotic early prophase: there was a degeneration or irregular proliferation of the tapetal cells. Other early aberrant events were the occurrence of numerous small vesicles in the microspore mother cells (MMC) and a disorganized chromatin condensation. Deviations that occurred in sterile anthers at later developmental stages included: (1) less distinct inner structures in the mitochondria of both MMC and tapetal cells from middle prophase onwards. (2) dilated ER and nuclear membranes at MMC prophase, in some cases associated with the formation of protein bodies. (3) breakdown of cell walls in MMCs and tapetal cells at late meiotic prophase. (4) no massive increase in tapetal ER at the tetrad stage. (5) a general dissolution of membranes, first in the MMC, then in the tapetum. (6) abortion of microspores and the occurrence of a plasmodial tapetum in anthers reaching the microspore stage. (7) no distinct degeneration of tapetal cells after microspore formation. Thus, it seems that the factors that lead to abortive microsporogenesis are structurally expressed at widely different times during anther development. Aberrant patterns are not restricted to the tetrad stage but occur at early prophase.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00190008
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  • 20
    Digitale Medien
    Digitale Medien
    Circadian photoreception in the retinally degenerate mouse (rd/rd) (1991)
    Springer
    Journal of comparative physiology 169 (1991), S. 39-50 
    Details
    ISSN: 1432-1351
    Schlagwort(e): Photoreception ; Retinally degenerate ; Mouse ; Circadian ; Rods ; Cones ; 11-cis retinaldehyde ; Immunocytochemistry ; HPLC
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary We have examined the effects of light on circadian locomotor rhythms in retinally degenerate mice (C57BL/6J mice homozygous for the rd allele: rd/rd). The sensitivity of circadian photoreception in these mice was determined by varying the irradiance of a 15 min light pulse (515 nm) given at circadian time 16 and meauring the magnitude of the phase shift of the locomotor rhythm. Experiments were performed on animals 80 days of age. Despite the loss of visual photoreceptors in the rd/rd retina, animals showed circadian responses to light that were indistinguishable from mice with normal retinas (rd/+ and +/+). While no photoreceptor outersegments were identified in the retina of rd/rd animals (80–100 days of age), we did identify a small number of perikarya that were immunoreactive for cone opsins, and even fewer cells that contained rod opsin. Using HPLC, we demonstrated the presence and photoisomerization of the rhodopsin chromophore 11-cis retinaldehyde. The rd/rd retinas contained about 2% of 11-cis retinaldehyde found in +/+ retinas. We have yet to determine whether the opsin immunoreactive perikarya or some other unidentified cell type mediate circadian light detection in the rd/rd retina.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00198171
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  • 21
    Digitale Medien
    Digitale Medien
    The roles of central and peripheral eclosion hormone release in the control of ecdysis behavior in Manduca sexta (1991)
    Springer
    Journal of comparative physiology 168 (1991), S. 697-707 
    Details
    ISSN: 1432-1351
    Schlagwort(e): Ecdysis ; Eclosion hormone ; Manduca sexta ; Neuropeptide ; Lepidoptera ; Pupal molt ; Verson's gland
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary 1. Ecdysis, a behavior by which insects shed the old cuticle at the culmination of each molt, is triggered by a unique peptide hormone, eclosion hormone (EH). In pupal Manduca sexta, EH is released into the hemolymph just prior to ecdysis, and circulating hormone is sufficient to elicit this behavior. 2. Removal of the proctodeal nerves in prepupal animals eliminated the appearance of blood-borne EH, but ecdysis behavior occurred on schedule. Therefore, circulating EH is not necessary for the triggering of ecdysis. 3. In contrast, a set of dermal glands failed to show their expected bout of secretion after proctodeal nerve removal. Injection of exogenous EH rescued this secretion. Thus, circulating EH appears necessary for action on peripheral but not central targets. 4. A major reduction in EH immunostaining is seen in the proctodeal nerves just preceding ecdysis; this coincides with a 〉90% reduction in extractable EH from this structure and the appearance of circulating EH. A similar, concomitant reduction was seen in central EH cell processes, suggesting release of peptide within the CNS. 5. Antidromic stimulation of the proctodeal nerve stumps following proctodeal nerve removal triggered precocious ecdysis. This result further supports the conclusion that centrally released EH is sufficient to trigger the motor program.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00224359
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  • 22
    Digitale Medien
    Digitale Medien
    Sensitivity of Trichoplusia ni (Hübner) pheromone receptor neurons: Relationships between neural thresholds and behavioral responses (1991)
    Springer
    Journal of comparative physiology 168 (1991), S. 739-747 
    Details
    ISSN: 1432-1351
    Schlagwort(e): Threshold ; Olfaction ; Insect ; Lepidoptera ; Noctuid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary 1. Responses of Trichoplusia ni HS(A) receptor neurons were measured to determine the minimum detectable concentration (absolute threshold) and the minimum detectable increment (difference threshold) for the major sex pheromone component (Z)-7-dodecen-1-ol acetate (Z7-12∶Ac). The absolute threshold was 1000-fold below the ∼10-11 M level of Z7-12∶Ac at a calling female. The Weber fraction, i.e., the ratio of the difference threshold to the stimulus concentration, declined from ∼0.8 to ∼0.06 as the concentration rose from threshold to high intensities. Relatively smaller fluctuations were detected as the stimulus increased. 2. The HS(A) responses were interpreted in relation to behavior by considering an ideal observer as approximating the central nervous system (CNS). The ideal thresholds were 3–9-fold lower than the HS(A) thresholds. 3. The ideal absolute threshold of the T. ni CNS is comparable to observed behavioral thresholds for wingflutter and taking flight. However, only a low percentage response occurs at threshold. Most males take flight at higher concentrations. Also, the ideal Weber fraction is lower than in most flight-tunnel bioassays. Yet, males respond to small fluctuations in orienting to pheromone plumes. These differences between moths and ideal observers may reflect inhibition at points in the CNS that control the flow of olfactory input.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00224362
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  • 23
    Digitale Medien
    Digitale Medien
    Fluoride effects on leaf cell ultrastructure of olive trees growing in the vicinity of the Aluminium Factory of Greece (1991)
    Springer
    Trees 5 (1991), S. 83-89 
    Details
    ISSN: 1432-2285
    Schlagwort(e): Air pollutants ; Chloroplasts ; Fluoride ; Olive tree leaves ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Leaves of olive trees growing in the vicinity of the Aluminium Factory of Greece were ultrastructurally investigated in order to determine any malformations caused by environmental air pollutants, especially hydrogen fluoride, in comparison with control samples and normal seasonal senescence. Estimation of some elements accumulated by these leaves showed that they contained high amounts of F and Al attributable to the operation of the nearby factory. The most seriously effected cell components were found to be the mesophyll chloroplasts that show a dilation of the intrathylakoid space, increase of the number of plastoglobuli, discoloration of plastoglobuli, accumulation of large starch grains and an overall disorganized appearance of the organelle. The nuclear crystalloid inclusions have unusual shapes, while the vacuoles contain a fibrillar/granular material that increases their electron density. It is concluded that the ultrastructural malformations are caused by a combination of environmental stresses and air pollutants.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227489
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  • 24
    Digitale Medien
    Digitale Medien
    Feeding responses ofChilo partellus (Swinhoe) (Lepidoptera: Pyralidae) larvae to sorghum plant phenolics and their analogs (1991)
    Springer
    Journal of chemical ecology 17 (1991), S. 67-78 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Chilo partellus ; Lepidoptera ; Pyralidae ; sorghum ; feeding response ; phenolics ; phagostimulant ; 4-hydroxybenzaldehyde ; 4-hydroxybenzoic acid ; 4-hydroxy-3-methoxycinnamic acid ; 3,4-dihydroxycinnamic acid ; 4-hydroxycinnamic acid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Phagostimulatory responses of third-instar larvae ofChilo Partellus to phenolic components identified in an ethyl acetate extract of the leaf whorls of 3-week-old plants ofSorghum bicolor cultivar IS 18363 were studied in no-choice bioassays. The major components in the extract were identified as 4-hydroxybenzaldehyde and 4-hydroxybenzoic acid, with 4-hydroxy-3-methoxycinnamic acid, 3,4-dihydroxycinnamic acid, and 4-hydroxycinnamic acid present in minor amounts. All but 4-hydroxycinnamic acid were stimulatory at the doses tested. 4-Hydroxybenzaldehyde was more stimulatory than other potential biogenetic analogs. Hydroxybenzoic acids generally elicited greater feeding response than cinnamic acids, and the pattern of oxygen substitution in the benzene ring was related to bioactivity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00994422
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  • 25
    Digitale Medien
    Digitale Medien
    Heliothis virescens: Response characteristics of receptor neurons in Sensilla Trichodea type 1 and type 2 (1991)
    Springer
    Journal of chemical ecology 17 (1991), S. 953-972 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Electroantennogram ; single-cell recordings ; olfactory receptor cells ; cobalt tracing ; sex pheromones ; (Z)-11-hexadecenal ; (Z)-9-tetradecenal ; host odors ; Heliothis virescens ; Lepidoptera ; Noctuidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Partial electroantennograms (EAGs) and single cell recordings fromHeliothis virescens males have demonstrated the presence of pheromones receptor neurons in sensilla trichodea type 2 as well as in type 1. This is supported by cobalt tracing experiments, showing that primary axons from the distal flagellum, containing only s. trichodea type 2, project into the macrogiomerulus complex in the male antennal lobes. Four types of finely tuned pheromone receptor neurons were found in males, whereas in females the corresponding neurons responded mainly to host odors. In males the majority (75 and 18%, respectively) were tuned to the majorHeliothis virescens pheromone components (Z)-11-hexadecenal (Z11-16∶A1) and (Z)-9-tetradecenal (Z9-14∶A1). The others (5 and 2%, respectively) responded specifically to (Z)-1 1-hexadecen-1-ol (Z1 1-16∶OH) and (Z)-1 1-hexadecen-1-ol acetate (Z1 1-16∶Ac). No neurons responding selectively to the minor pheromone components were found. The Z11-16∶A1 neurons of both sensilla types possessed similar specificity. However, the sensitivity decreased toward the medial and distal part of the flagellum, where s. trichodea type 2 are located. This suggests that the pheromone concentrations can be detected peripherally by a spatial as well as a temporal mechanism. Differences in temporal response patterns (pronounced phasic vs. tonic component) were found within the same type of neurons, suggesting different ability to encode intermittency of the pheromone plume as well as to mediate maintenance of flight.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01395602
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  • 26
    Digitale Medien
    Digitale Medien
    Impact of UV radiation on activity of linear furanocoumarins andBacillus thuringiensis var.Kurstaki againstSpodoptera exigua: Implications for tritrophic interactions (1991)
    Springer
    Journal of chemical ecology 17 (1991), S. 973-987 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Linear furanocoumarins ; Spodoptera exigua ; Lepidoptera ; Noctuidae ; UV light ; tritrophic interactions ; Bacillus thuringiensis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Acidic fogs with a pH of 2.0 and duration of 2 hr did not reduce the efficacy ofBacillus thuringiensis var.Kurstaki (Berliner). Therefore, the impact of UV radiation was investigated on the interactions between (1) levels of the antibacterial linear furanocoumarins psoralen, bergapten, and xanthotoxin inApium graveolens (L.) occurring following a 2.0 pH acidic fog episode, (2) the noctuidSpodoptera exigua (Hübner), and (3) a sublethal dosage of the microbial pathogenB. thuringiensis var.Kurstaki. Mean time to pupation in the absence of UV radiation (survival was too low to conduct this analysis for insects exposed to UV) was significantly extended by the addition of either psoralens orB. thuringiensis. Larvae developing on diets containingB. thuringiensis plus psoralens required nearly 40% longer to pupate than controls, but their effects were additive as the interaction was not significant. Although the mean times to adult emergence were significantly different, time spent in the pupal stage did not vary significantly between treatments, indicating that increases in larval developmental time were responsible for the observed decrease in developmental rate. Mean time to mortality, a weighted average time of death, was not significantly affected by any of the treatments. In a 2 × 2 × 2 factorial analysis, all main effects (linear furanocoumarins.B. thuringiensis, UV radiation) reduced survival significantly, as did the three-way interaction. Thus, antagonistic interactions with psoralens that would reduce the effectiveness ofB. thuringiensis in the field were not observed. When pairs of main effects were nested within the two levels (presence and absence) of the third factor, several two-way interactions were found. Interestingly, the activity ofB. thuringiensis and the psoralens, individually or in combination, was enhanced by exposure to UV radiation. Implications of this research are discussed for both natural and agricultural ecosystems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01395603
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  • 27
    Digitale Medien
    Digitale Medien
    Sex pheromone of the european sunflower moth,Homoeosoma nebulellum (Den. & Schiff.) (Lepidoptera: Pyralidae) (1991)
    Springer
    Journal of chemical ecology 17 (1991), S. 1399-1414 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Lepidoptera ; Pyralidae ; Homoeosoma nebulellum ; European sunflower moth ; sex pheromone ; identification ; multicomponent blend ; (Z,E)-9,12-tetradecadienal
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Four components, (Z)-9-tetradecenal (8.6%), (Z,E)-9,12-tetradecadienal (4.8%), (Z)-11-hexadecenal (49.5%), and (Z)-13-octadecenal (37.1%), were identified in extracts of female pheromone glands of the European sunflower moth,Homoeosoma nebulellum (Lepidoptera: Pyralidae) using GC and GC-MS analyses. EAG and single-cell recordings of male antennal receptors gave strong evidence for (Z,E)-9,12-tetradecadienal as the antennal key compound of sex pheromone detection in this species. This result was confirmed by field trapping; removal of (Z,E)-9,12-tetradecadienal from quaternary blends completely suppressed the male catches. The synthetic blends with this compound as a major component caught five times less males than the blends reproducing the ratio found in the female extracts [5% of (Z,E)-9,12-tetradecadienal only]. The occurrence of a minor component perceived as the most biologically relevant compound is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00983772
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  • 28
    Digitale Medien
    Digitale Medien
    Adaptive significance of furanocoumarin diversity inPastinaca sativa (Apiaceae) (1991)
    Springer
    Journal of chemical ecology 17 (1991), S. 207-215 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Heliothis zea ; corn earworm ; Lepidoptera ; Noctuidae ; Pastinaca sativa ; wild parsnip ; Apiaceae ; furanocoumarins ; defense ; xanthotoxin ; photoactivation ; bioassay
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Fruits ofPastinaca sativa (Apiaceae), the edible parsnip, contain six different furanocoumarins that are differentially capable of ultraviolet-mediated cross-linkage of DNA and inhibition of DNA transcription. Individually, none of the other furanocoumarins present in parsnip seeds is as toxic as the photosensitizer xanthotoxin. Nevertheless, the natural mixture of compounds is toxicologically more effective againstHeliothis zea (Lepidoptera: Noctuidae), both in the presence and absence of UV light, than is an equimolar amount of xanthotoxin. The difference in toxicity diminishes with increasing light levels. Thus, a series of structurally related natural products can display toxicity lacking in individual compounds and may represent an adaptive compromise to varying environmental conditions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00994434
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  • 29
    Digitale Medien
    Digitale Medien
    Dual role of pyrrolizidine alkaloids in nectar (1991)
    Springer
    Journal of chemical ecology 17 (1991), S. 195-205 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Pyrrolizidine alkaloids ; pollination ; nectar constituents ; Ithomiinae ; Danainae ; Heliconiinae ; Lepidoptera ; Nymphalidae ; agraulis vanillae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Pyrrolizidine alkaloids occur in several plant families, attracting ithomiine and danaine butterflies that specialize on the flowers. I show that pyrrolizidine alkaloids in artificial nectar also inhibit at least one butterfly,Agraulis vanillae (Nymphalidae: Heliconiinae), a more general forager. Inhibition was demonstrated in two ways: quantity of nectar consumed and number of artificial flowers visited. The amount of sucrose solution consumed by individual butterflies was measured using a microcapillary tube. Number of flower visits was determined using an array of artificial orange and yellow flowers.A. vanillae drank less sucrose solution with monocrotaline, a pyrrolizidine alkaloid, than without. When monocrotaline was placed into yellow flowers,A. vanillae learned to visit predominantly orange flowers. Evolutionarily, pyrrolizidine alkaloids in nectar may represent an adaptation to exclude butterflies. Ithomiines and danaines, seeking these compounds in larval food plants, were not excluded. Alternatively, ithomiines and danaines overcame the nectar defense. In either case, the plant effectively increased floral constancy by inhibiting generalist butterflies and attracting specialists.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00994433
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  • 30
    Digitale Medien
    Digitale Medien
    Identification of hairpencil secretion from maleMamestra brassicae (L.) (Lepidoptera: Noctuidae) and electroantennogram studies (1991)
    Springer
    Journal of chemical ecology 17 (1991), S. 239-246 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Mamestra brassicae ; Lepidoptera ; Noctuidae ; hairpencils ; male-produced compounds ; identification ; benzaldehyde ; 2-methylpropanoic acid ; 2-methylbutanoic acid ; benzyl alcohol ; 2-phenylethanol ; phenol ; electroantennography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Extracts of maleMamestra brassicae (L.) hairpencils were analyzed by capillary gas chromatography (GC) and by GC-mass spectrometry (GC-MS). The extracts were found to consist of six components. Benzaldehyde, 2-methylpropanoic acid, 2-methylbutanoic acid, and phenol were present in the extracts as well as the previously identified benzyl alcohol and phenyl ethanol. The two major components were 2-phenylethanol and 2-methylbutanoic acid. They represented, respectively, 74% and 12.5% of the total blend in 3-day-old male extracts. Electroantennograms were recorded on male and female antennae in response to stimulation by hairpencil compounds. Male and female antennae responded to each chemical but the female responses were significantly higher than those of the males.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00994436
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  • 31
    Digitale Medien
    Digitale Medien
    α-Tocopherol alteration of soybean antiherbivory toTrichoplusia ni larvae (1991)
    Springer
    Journal of chemical ecology 17 (1991), S. 1941-1951 
    Details
    ISSN: 1573-1561
    Schlagwort(e): α-Tocopherol ; elicitor ; alterable resistance ; soybean ; Trichoplusia ni ; Lepidoptera ; Noctuidae ; antiherbivory
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The antioxidant vitamin E, α-tocopherol, was tested as a candidate elicitor of alterable antiherbivory in soybean plants against cabbage looper larvae. Although a nonspecific antioxidant, vitamin E proved elicitory to the involved sulfhydryl-dependent receptor-energy transducer protein in soybean plasma membrane. Effects of α-tocopherol were dependent on dosage, time, and space in the plant. The observed elicited effects were all decreases in herbivory. The best negative phytochemical correlate of looper feeding was the percentage of increased total HPLC peak area of extractables from elicited as compared to nonelicited leaves. Some specific compounds, e.g., glyceollins, were quantitatively major components of the total profile of secondary metabolites.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00992579
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  • 32
    Digitale Medien
    Digitale Medien
    Evidence for presence and nature of female sex pheromone ofBrithys crini fabricius (Lepidoptera: Noctuidae) (1991)
    Springer
    Journal of chemical ecology 17 (1991), S. 2035-2042 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Sex pheromone ; (Z)-11-hexadecenal ; Brithys crini ; Lepidoptera ; Noctuidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The existence of a female sex pheromone of the noctuid mothBrithys crini Fabricius was confirmed in both laboratory bioassay and field tests. Crude extracts and airborne volatiles from females were analyzed by gas chromatography and mass spectrometry and the data compared with authentic compounds. The primary sex pheromonal compound was Z11-16: Ald. Scanning electron microscopy showed that the external surface of the sex pheromone gland was covered with folds that might increase the sex pheromone evaporation area.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00992586
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  • 33
    Digitale Medien
    Digitale Medien
    Mint root borer,Fumibotys fumalis (Guenee): Identification and field tests of female sex pheromone gland components (1991)
    Springer
    Journal of chemical ecology 17 (1991), S. 249-258 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Lepidoptera ; Pyralidae ; Pyraustinae ; Pyraustini ; Fumibotys fumalis ; sex pheromone ; (E,E)-10 ; 12-tetradecadienyl acetate ; (Z)-11-tetradecenyl acetate ; (E)-11-tetradecenyl acetate ; (Z)-9-tetradecenyl acetate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Compounds identified in sex pheromone gland extracts of femaleFumibotys fumalis (Guenee) consisted of (E,E)-10,12-tetradecadienyi acetate, (Z)-11-tetradecenyl acetate, (E)-11-tetradecenyl acetate, and (Z)-9-tetradecenyl acetate in a ratio of 100:18: 8:4, respectively. The compounds were identified by electroantennographic, gas Chromatographic, mass spectrometric, and chemical derivatization procedures. In mint fields synthetic components in gray elastomeric septa at ratios found in the sex pheromone gland and at doses of 3 or 10 mg of the diene produced trap catch comparable to traps baited with three females.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00994330
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  • 34
    Digitale Medien
    Digitale Medien
    European corn borer: Pheromonal catabolism and behavioral response to sex pheromone (1991)
    Springer
    Journal of chemical ecology 17 (1991), S. 317-334 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Antennal catabolism ; Ostrinia nubilalis ; Lepidoptera ; Pyralidae ; pheromone analogs ; 11-tetradecenyl acetate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract When physiologically excessive amounts of the female sex pheromone of the European corn borer (ECB) or esters analogous to the pheromone were applied to the antennae of males, their behavioral responsiveness to pheromone in a flight tunnel was significantly impaired for 2 hr. Concurrent quantitative analyses of heptane extracts of the male antennae by gasliquid chromatography showed that the compounds applied to antennae were hydrolyzed and, at 2 and 4 hr posttreatment, little or none of the compound applied or hydrolysis product was detectable in the antennal extracts. After 4 hr of in vivo incubation, male responsiveness to pheromone was restored among moths treated with the analogs but not among moths treated with pheromone. Esterase activity on the antennae was moderately inhibited in vivo by a pheromone analog that is a so-called transition-state esterase inhibitor, 1,1, 1-trifluoro-14-heptadecen-2-one. However, the analog did not inhibit male behavior when it was coevaporated with pheromone in a flight-tunnel assay. Therefore, in the presence of pheromone, the analog did not compete well for esterase or the pheromone receptor. Treating the antennae of intact males with tetrahydrofuran obliterated sex pheromone response capability in males, but the treatment did not significantly attenuate esterase and other catabolic activity of the antennae. Indications are that degradation of esters on the ECB antennae involves substrate-nonspecific esterase activity and other metabolic processes that in turn remove hydrolysis products from the antennae. Maintenance of a male's ability to respond to pheromone is linked to these processes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00994335
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  • 35
    Digitale Medien
    Digitale Medien
    Selection of pheromone trap and attractant dispenser load to monitor black army cutworm,Actebia fennica (1991)
    Springer
    Journal of chemical ecology 17 (1991), S. 309-316 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Actebia fennica ; Lepidoptera ; Noctuidae ; cutworm ; pheromone traps ; pheromone ; monitoring
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Catch rates of black army cutworm moths,Actebia fennica (Lepidoptera: Noctuidae), were determined for different types of traps and different dispenser loads of sex attractant. Of the five traps tested, highest catch (35 males/per night) was obtained with Uni-Traps, whereas Pherocon 1CP, Delta and Hara traps rapidly became saturated at 9, 6, and 11 males/per night, respectively. Multi-Pher traps, like the Uni-Traps, have a covered vertical cone with a large collecting bucket but only catch about 1/3 of the number of moths (9 males/per night) as the Uni-Traps, thus reducing potential saturation. Red rubber septa loaded with 500 μg of attractant blend gave a consistent catch for at least 60 days; 1000 and 2000 μg loadings lasted for a minimum of 90 days. Polyvinylchloride and red rubber septa dispensers containing 100 μg of attractant had similar catch rates, which decreased rapidly with age. Based on these trap and lure-loading experiments, Multi-Pher traps baited with 1000 μg of attractant in a red rubber septum were selected for future calibration studies between catch density and population fluctuations on susceptible sites. Two years of monitoring results also are reported.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00994334
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  • 36
    Digitale Medien
    Digitale Medien
    Intraspecific variation and interspecific differences in sex pheromones of sibling species inCtenopseustis obliquana complex (1991)
    Springer
    Journal of chemical ecology 17 (1991), S. 413-429 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Ctenopseustis obliquana ; Tortricinae ; Lepidoptera ; pheromones ; (Z)-5-tetradecenyl acetate ; (Z)-8-tetradecenyl acetate ; sibling species ; blend preferences ; electrophysiology ; intraspecific variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The specific status ofCtenopseustis obliquana pheromone-types I, II, and III has been more fully examined. Females of types I and III produce a mixture of (Z)-8- and (Z)-5-tetradecenyl acetates (Z8-14:Ac, Z5-14: Ac). The previously reported different ratios of these two components in females of the two types (type I=80∶20, III=90∶10) have been reinvestigated. The median ratios of each type differed significantly, although there was some overlap in the ranges of these ratios. A field cage trial showed that males of type III are attracted to females of type I, so the observed differences may be ascribed to intraspecific variation. In contrast to females of types I or III, females of type II produce Z5-14∶Ac but no Z8-14∶Ac. The electroantennogram (EAG) profile of antennae of type II males shows a maximum response to Z5-14∶Ac, while the EAG profiles of types I and III show a strong response to Z8-14∶Ac. In wind tunnel tests using mixtures of these two compounds, type II males prefer blends consisting of all or mostly Z5-14: Ac, while type I males showed a preference to a mix of 70% Z8-14∶Ac plus 30% Z5-14∶Ac. We found that type I males are attracted to type I females when offered a choice between type I and type II females in a field cage test and that type II males similarly prefer type II females. Males of types I and II have specialist cells for Z8-14∶Ac and Z5-14∶Ac but differ with respect to relative densities of these cells and to further cell types responsive to other alkenyl acetates. Type IIC. obliquana is considered therefore a sibling species of types I and III. In addition, the amount of Z5-14∶Ac produced by type II females varied geographically. Females from the North Island produced significantly less (median=1.2 ng) Z5-14∶Ac than females from the South Island (median=2.2 ng). Type II populations in the North Island morphologically resembled sympatric type I, rather than type II from the South Island and are designated as type II (North Island). Type II (North Island) populations have so far been found only at Rukuhia (near Hamilton) and from Kerikeri. In contrast, type II populations are sympatric with type III populations over much of the South Island. In a field cage trial, males of types II and II (North Island) were attracted to females of both II and II (North Island). We tentatively ascribe the differences between type II and type II (North Island) to intraspecific variation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00994342
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  • 37
    Digitale Medien
    Digitale Medien
    Peptidergic motoneurons in the buccal ganglia of Aplysia californica Immunocytochemical, morphological, and physiological characterizations (1991)
    Springer
    Journal of comparative physiology 168 (1991), S. 323-336 
    Details
    ISSN: 1432-1351
    Schlagwort(e): Aplysia ; Motoneurons ; Immunocytochemistry ; Small cardioactive peptides ; Facilitation ; Depression ; Buccal ; Feeding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary We used physiological recordings, intracellular dye injections and immunocytochemistry to further identify and characterize neurons in the buccal ganglia of Aplysia calif ornica expressing Small Cardioactive Peptide-like immunoreactivity (SCP-LI). Neurons were identified based upon soma size and position, input from premotor cells B4 and B5, axonal projections, muscle innervation patterns, and neuromuscular synaptic properties. SCP-LI was observed in several large ventral neurons including B6, B7, B9, B10, and B11, groups of s1 and s2 cluster cells, at least one cell located at a branch point of buccal nerve n2, and the previously characterized neurons B1, B2 and B15. B6, B7, B9, B10 and B11 are motoneurons to intrinsic muscles of the buccal mass, each displaying a unique innervation pattern and neuromuscular plasticity. Combined, these motoneurons innervate all major intrinsic buccal muscles (I1/I3, I2, I4, I5, I6). Correspondingly, SCP-LI processes were observed on all of these muscles. Innervation of multiple nonhomologous buccal muscles by individual motoneurons having extremely plastic neuromuscular synapses, represents a unique form of neuromuscular organization which is prevalent in this system. Our results show numerous SCPergic buccal motoneurons with widespread ganglionic processes and buccal muscle innervation, and support extensive use of SCPs in the control of feeding musculature.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00198352
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  • 38
    Digitale Medien
    Digitale Medien
    Cellular localization of somatolactin in the pars intermedia of some teleost fishes (1991)
    Springer
    Cell & tissue research 263 (1991), S. 207-215 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Somatolactin (SL) ; Pituitary gland, pars intermedia ; PAS-positive cells ; Immunocytochemistry ; Gadus morhua, Oncorhynchus mykiss, Poecillia latipinna (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary We report here on the cellular localization in the fish pituitary of somatolactin (SL), a putative new pituitary hormone related to growth hormone and prolactin, which has been recently identified in the piscine pituitary gland. Immunocytochemical staining, using anti-cod SL serum, revealed that in the cod pituitary gland, SL is produced by cells in the intermediate lobe, bordering the neural tissue. These cells, staining weakly with periodic-acid-Schiff (PAS), are distinct from the melanocyte stimulating hormone (MSH) cells which, as in all teleosts, are PAS-negative. SL-immunoreactivity was observed in the same location in all other teleost species examined: flounder, rainbow trout, killifish, molly, catfish and eel. In most fish the SL-immunoreactive cells are either strongly or weakly PAS-positive but in rainbow trout are chromophobic, indicating that the SL protein can probably exist in glycosylated and non-glycosylated forms. Thus, in demonstrating the cellular localization of SL, this study provides the first identification of the enigmatic, second cell-type of the fish pars intermedia.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318762
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  • 39
    Digitale Medien
    Digitale Medien
    Qualitative and quantitative comparison of the distribution of phosphorylated and non-phosphorylated neurofilament epitopes within central and peripheral axons of adult hamster (Mesocricetus auratus) (1991)
    Springer
    Cell & tissue research 263 (1991), S. 265-270 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Neurofilaments ; Phosphorylation ; Axon ; Immunocytochemistry ; Golden syrian hamster, Mesocricetus auratus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of phosphorylated and nonphosphorylated neurofilament epitopes was determined immunocytochemically in adjacent 2 μm-thick sections of sciatic nerve, ventral root and spinal cord. Staining was scored as either intense, moderate or absent and the proportion of labeled axons was calculated for each category. Nearly all sciatic nerve and ventral root axons were immunoreactive with both antibodies against phosphorylated and non-phosphorylated neurofilaments and there were no significant differences in the number of intensely- or moderately-labeled axons. Within the spinal cord however, while the majority of large caliber axons was stained with both antibodies, there was a significant number of small caliber axons which stained only with antibodies against phosphorylated neurofilaments. These results show that phosphorylated and nonphosphorylated neurofilaments are extensively codistributed in CNS and PNS axons, and that in the CNS, staining intensity for non-phosphorylated epitopes is less in the smaller axons.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318768
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  • 40
    Digitale Medien
    Digitale Medien
    The serotoninergic system in the brain of the Japanese quail (1991)
    Springer
    Cell & tissue research 263 (1991), S. 271-284 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Serotonin ; Immunocytochemistry ; Avian brain ; Hypothalamus ; Japanese quail, Coturnix coturnix japonica (Aves)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The presence and topographical localization of the serotoninergic system in the brain of the Japanese quail (Coturnix coturnix japonica) have been studied by means of peroxidase-anti-peroxidase immunocytochemistry. The perimeter, diameter, area, and shape factor of immunoreactive cells have been recorded and analyzed morphometrically for intra- and interspecies comparison. The data reported here confirm and extend results previously obtained in the brain of other avian species. Serotonin-immunoreactive neurons of the quail are mainly located in the hypothalamic paraventricular organ and adjacent areas, and in the brainstem where they form three separate groups. The first of these groups consists of small-sized neurons located in the ventro-rostral mesencephalon. The second group is composed of medium-sized neurons located in the dorsal mesencephalo-pontine region. The third group is also formed by medium-sized neurons, and is located ventrally in the ponto-medullary region. In the quail brain, serotoninergic neurons are not restricted to nuclei located in the vicinity of the midsagittal plane, but show some lateralization, especially in the brainstem. The organization of the different groups of immunoreactive neurons based on this topographical distribution and morphometric analysis has been compared with descriptions of the serotoninergic system in other birds. Serotonin-immunoreactive nerve fibers are widely distributed throughout the brain, but appear to be particularly abundant in regions involved in the control of reproductive activities, such as the septal region, the medial preoptic nucleus, the nucleus intercollicularis, and the external zone of the median eminence. The data reported here have allowed the drawing of a map of serotoninimmunoreactive structure.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318769
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  • 41
    Digitale Medien
    Digitale Medien
    Immunocytochemical mapping of neuronal pathways from brain to corpora cardiaca/corpora allata in the cockroach Diploptera punctata with antisera against Met-enkephalin-Arg6-Gly7-Leu8 (1991)
    Springer
    Cell & tissue research 263 (1991), S. 285-291 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Met-enkephalin-Arg6-Gly7-Leu8 ; Immunocytochemistry ; Neuropeptides ; Allatostatins ; Neurosecretory cells ; Corpus cardiacum/corpus allatum complex ; Diploptera punctata, Calliphora vomitoria (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Neuronal circuits in the brain and retrocerebral complex of the cockroach Diploptera punctata have been mapped immunocytochemically with antisera directed against the extended enkephalin, Met-enkephalin-Arg6-Gly7-Leu8 (Met-8). The pathways link median and lateral neurosecretory cells with the corpus cardiacum/corpus allatum complex. In females, nerve fibres penetrate the corpora allata and varicosities or terminals, immunoreactive to Met-8, surround the glandular cells. Males differ in having almost no Met-8 immunoreactivity in the corpora allata. The corpora cardiaca of both males and females are richly supplied with Met-8 immunoreactive material, in particular in the ‘cap’ regions immediately adjacent to the corpora allata. A similarity in the amino-acid sequences of Met-8 and the C-terminus of the recently characterised allatostatins of D. punctata suggests that the pathways identified with the Met-8 antisera may be the same as those by which the allatostatins are transported from the brain to the corpus allatum. In comparative studies on the blowfly Calliphora vomitoria, similar neuronal pathways have been identified except that no sexual dimophism with respect to amounts of immunoreactive material within the corpus allatum has been observed. These results suggest a possible homology in the neuropeptide regulation of the gland.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318770
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  • 42
    Digitale Medien
    Digitale Medien
    Immunocytological localization of 1,25-dihydroxyvitamin D3-like molecules and their receptors in a calcium-transporting epithelium of a crustacean (1991)
    Springer
    Cell & tissue research 263 (1991), S. 345-351 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Vitamin D-1,25(OH)2D3-like immunoreactivity ; 1,25(OH)2D3 receptor-like immunoreactivity ; Immunocytochemistry ; Calcium ions ; Orchestia cavimana (Crustacea)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary For the first time, immunoreactivity to 1,25(OH)2D3-like molecules and their receptors has been investigated in a calcium transporting epithelium of a crustacean, Orchestia, using vertebrate antisera on ultrathin cryosections of posterior caeca previously fixed in glutaraldehyde, then postfixed in osmium tetroxide. Both immunoreactivities were located mainly in the nuclei of epithelial cells. Quantitative differences in 1,25(OH)2D3-like immunoreactivity were noticed from one stage of the molt cycle to another. These results, together with other data, contribute to evidence that immunoreactive 1,25(OH)2D3-like molecules may be involved in the regulatory processes of calcium metabolism in this terrestrial crustacean and suggest an involvement of these substances in the regulation of calcium movements in the posterior caeca.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318776
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  • 43
    Digitale Medien
    Digitale Medien
    Different epithelia in the distal human male urethra (1991)
    Springer
    Cell & tissue research 264 (1991), S. 23-32 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Male urethra ; Urethral epithelium ; Immunocytochemistry ; Ultrastructure ; Man
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distal segment of the human male urethra, in particular the fossa navicularis, was studied with light- and electron microscopy as well as by means of histochemical and immunocytochemical methods. The fossa navicularis of the urethra contains a circumscribed zone of extremely thick, non-keratinized stratified squamous epithelium composed of cells containing a large amount of glycogen. These cells lack acid phosphatase activity and lysozyme-like immunoreactivity, both of which can be demonstrated to varying extents in the other zones of the distal male urethra. These glycogen-rich cells are considered to be the substrate for an endogenous flora of lactobacteria, whereas the acid-phosphatase activity and the lysozyme-like immunoreactivity indicate the presence of macrophages and the secretion of bactericidal agents at the epithelial surface. These observations suggest that the different zones with heterogeneous properties in the distal male urethra probably represent a defense system against the invasion of pathogenic microorganisms. Moreover, the glycogen-rich zone, which resembles the glycogen-rich epithelium of the vagina, is estrogen-dependent. This is demonstrated in cases of sex reversal in which after long-lasting estrogen treatment the glycogen-rich zone becomes extremely extended by displacement of the neighbouring epithelium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00305719
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  • 44
    Digitale Medien
    Digitale Medien
    Enkephalin-immunoreactive cells in the mesencephalic tegmentum project to the optic tectum of the teleosts Salmo gairdneri and Salmo salar (1991)
    Springer
    Cell & tissue research 264 (1991), S. 133-137 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Enkephalins ; Tegmentum mesencephali ; Tectum opticum ; Immunocytochemistry ; Retrograde labeling ; Cobalt-lysine ; Salmo gairdneri, Salmo salar (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Immunocytochemistry using antibodies against Met-enkephalin and Leu-enkephalin has demonstrated a group of large enkephalin-immunoreactive neurons in the nucleus of the rostral mesencephalic tegmentum (mRMT) of two teleost fish, Salmo gairdneri and Salmo salar. Injections of cobalt-lysine in the medial optic tectum retrogradely labeled the above group of tegmental neurons. Tegmental neurons were labeled only ipsilaterally to the injection site. This indicates that enkephalinergic neurons in the nRMT project to the optic tectum, and that at least some of the enkephalinergic axons observed in the optic tectum belong to a tegmento-tectal pathway. Comparable enkephalinergic pathways have been described in reptiles and birds, where pretectal-mesencephalic nuclei contribute to the enkephalin-containing fibers that project to the optic tectum.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00305731
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  • 45
    Digitale Medien
    Digitale Medien
    Development of the endocrine pancreas during larval phases of Rana temporaria (1991)
    Springer
    Cell & tissue research 264 (1991), S. 139-150 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Pancreas, endocrine ; Larval development ; Serial thin/semithin sections ; Immunocytochemistry ; Rana temporaria (Anura)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The pancreatic endocrine component was studied at different stages of development in the tadpoles of Rana temporaria. The material was embedded in Epon, and serial semithin and thin sections were made in order to correlate ultrastructural features and tinctorial traits of the endocrine cells. Serial semithin sections were also stained with the peroxidase-antiperoxidase immunocytochemical method and with silver impregnations for argyrophilia and argentaffinity. In early larvae (legless tadpoles), A and B cells are present. Both can be found within ducts and exocrine tissue or, more frequently, in cellular clusters among the ducts and acini. These primitive islets are solid structures, surrounded but not penetrated by capillaries. Mitoses were observed in A and B cells. In the following phase (tadpoles with hindlegs), D and pancreatic polypeptide-immunoreactive cells are also present, as well as numerous endocrine cells scattered among exocrine tissue. There is also a change in the vascular-insular pattern: capillaries not only surround but also penetrate the endocrine group. The structure of the endocrine pancreas in older tadpoles is similar. Tinctorial traits and ultrastructural features of endocrine cells are described, and the origin of primitive islets is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00305732
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  • 46
    Digitale Medien
    Digitale Medien
    The distribution of gonadotropin-releasing hormone (GnRH) neurons and fibers throughout the chick brain (Gallus domesticus) (1991)
    Springer
    Cell & tissue research 264 (1991), S. 481-495 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Immunocytochemistry ; Neuropeptide Y ; Gonadotropin-releasing hormone ; Reproductive function ; Domestic chicken, Gallus domesticus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Nerve fibers and perikarya containing gonadotropin-releasing hormone (GnRH-like) immunoreactivity were investigated in the brain of the three-week-old chick, Gallus domesticus using the technique of immunocytochemistry. Six major groups of perikarya were found to include the olfactory bulb, olfactory tubercle/lobus parolfactorius, nucleus accumbens, septal preoptic hypothalamic region (three sub-nuclei), lateral anterior thalamic nucleus and in and about the oculomotor complex. The immunostaining was unusual in the latter group, suggesting that the neurons may contain a GnRH-II like material. Immunoreactive fibers for GnRH were found throughout the entire brain extending from the olfactory bulbs to the caudal brainstem. Two anatomical areas, not emphasized in the past literature, which had distinct GnRH-like immunoreactivity, included the lateral anterior thalamic nucleus and the preoptic recess. The former included a group of GnRH perikarya that is also known to be a retino-recipient area while the latter contained neuronal terminals some of which appeared to be contacting the cerebrospinal fluid of the preoptic recess. An attempt was made to list all anatomical structures that contained or were juxta-positioned to sites that displayed immunoreactive perikarya and fibers including circumventricular organs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319038
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  • 47
    Digitale Medien
    Digitale Medien
    The distribution of actin immunoreactivity in rhabdomeres of tipulid flies in relation to extracellular membrane shedding (1991)
    Springer
    Cell & tissue research 265 (1991), S. 465-472 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Rhabdomeres ; Cytoskeleton ; Actin ; Immunocytochemistry ; Membrane shedding ; Leptotarsus spp. (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Rhabdomeres of tipulid flies lose membrane during turnover from a ‘shedding zone’ composed of microvillar tips. These distal domains lack intramicrovillar cytoskeletons and appear to be empty sacs of membrane. Recent concerns about the role of ninaC mechano-enzymes in the architecture of dipteran rhabodomeral microvilli and the dynamic role that they may play in the creation of shedding zones demand an examination of the distribution of actin in tipulid rhabdomeres. We compared rhabdomeres from tipulid retinae incubated before fixation for immunocytochemistry in a buffer without additives and a stabilising buffer that contained a cocktail of cysteine protease inhibitors; both were challenged by an anti-actin antibody for immunogold labelling after embedding in LR White Resin. Shedding zones thus processed collapse to structureless detritus. Stabilised and unstabilised shedding zones were immunonegative to anti-actin. To ensure that the negative results were not consequent upon conformational changes generated by the processing protocol, we examined microvilli of degenerating rhabdomeres of the Drosophila light-dependent retinal degeneration mutant rdgB KS222 (which separate and collapse without creating a shedding zone) and found the detritus they generate to be immunopositive to anti-actin. Stabilised and unstabilised regions of basal regions of tipulid rhabdomeres were equally immunopositive. We infer that (a) actin is absent from shedding zones; (b) actin is not degraded by microvillar cysteine proteases. The implications of these conclusions are discussed in relation to some functional models of arthropod photoreceptor microvilli.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00340869
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  • 48
    Digitale Medien
    Digitale Medien
    Corticotropin-like immunoreactivity in the brain of intact, hypophysectomized, cortisol- and metopirone-treated eels (1991)
    Springer
    Cell & tissue research 265 (1991), S. 485-492 
    Details
    ISSN: 1432-0878
    Schlagwort(e): ACTH ; Brain ; Hypothalamus ; Hypophysectomy ; Cortisol ; Metopirone ; Immunocytochemistry ; Pituitary ; Corticotropin-releasing factor ; Anguilla anguilla (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary An ACTH-like peptidergic system was demonstrated in the brain of three teleost species by immunocytochemistry. In order to investigate the origin of brain ACTH and factors modulating its synthesis, similar techniques were applied to the brain of eels (1) submitted to hypothysectomy in order to suppress pituitary ACTH and plasma cortisol, (2) injected with cortisol to inhibit pituitary ACTH synthesis and release, and (3) injected with metopirone to block cortisol synthesis and stimulate ACTH synthesis and release. Hypophysectomized eels showed a normal distribution of immunoreactive perikarya in the ventral hypothalamus and fibers in the brain, suggesting that brain ACTH does not arise from the pituitary. In cortisol-treated eels immunostaining was markedly reduced in brain perikarya and pituitary corticotropes, suggesting a reduced synthesis. In metopirone-injected eels, one third of the animals showed an increased immunostaining in perikarya and a dense network of immunoreactive fibers, suggesting that ACTH synthesis was increased. Brain ACTH was not affected in other animals. Pituitary corticotropes were rapidly degranulated. Responses of ACTH in the brain and pituitary occur independently when cortisol synthesis is inhibited. These responses are compared to those of the corticotropin-releasing factor system in the same eels.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00340871
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  • 49
    Digitale Medien
    Digitale Medien
    Growth of enteric neurones from isolated myenteric ganglia in dissociated cell culture (1991)
    Springer
    Cell & tissue research 265 (1991), S. 527-534 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Autonomic nervous system ganglia ; Enteric nervous system ; Intestine, large ; Tissue culture ; Immunocytochemistry ; Peptides ; Guinea-pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Ganglia of the myenteric plexus from the newborn guinea-pig, isolated by microdissection, were dissociated by a combination of enzymatic and mechanical methods. The neurones and glial cells in the resulting cell suspension were cultured for up to 21 days in vitro. The growth of the enteric ganglion cells in serum-free, hormone-supplemented (N1) medium and in serum-supplemented medium containing a mitotic inhibitor was compared over a period of 14 days in vitro. Enteric neurones were outnumbered by glia in both culture media, although glial cell proliferation was inhibited in both media compared with that in serum-supplemented medium without mitotic inhibitors. Glial cell numbers appeared to decline in serum-free medium after the first week in vitro. Neurites tended to be more varicose in the serum-free medium, and the morphology of the enteric glial cells also differed markedly in the two media. This is the first report of the dissociation and subsequent culture of myenteric ganglia that had previously been completely isolated from the remainder of the gut wall.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00340876
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  • 50
    Digitale Medien
    Digitale Medien
    A cytochemical and immunocytochemical study of DNA distribution in spermatid nuclei of mouse, rabbit, and bull (1991)
    Springer
    Cell & tissue research 265 (1991), S. 517-525 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Spermiogenesis ; Spermatids ; DNA ; Immunocytochemistry ; Electron microscopy ; Bovine ; Mouse ; Rabbit
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary DNA distribution in mouse, rabbit and bull spermatids was analyzed by electron microscopy, after using a Feulgen-like HCl-osmium ammine procedure, and after immunocytochemistry with anti-DNA antibodies. In addition, nucleic acids were visualized with the intercalating dye ethidium bromide and phosphotungstic acid. The parts of DNA displaying a beta helix configuration (possibly A-T rich parts) were identified by epifluorescence microscopy after staining with Hoechst 33258. In all 3 species, young spermatid nuclei were seen to have large areas poor in DNA, as well as DNA-rich areas, which were mostly concentrated into a peripheral layer close to the acrosome and into one or several masses, displaying species-specific locations. These DNA-rich areas were stained with Hoechst 33258. Elongating spermatid nuclei contained homogeneously distributed DNA, and this was evident following both immunocytochemistry and nucleic acid histochemistry in all 3 species. However, the distribution appeared more heterogeneous after the Feulgen-like procedure, and was accompanied by a disappearance of Hoechst-fluorescence. In fully elongated spermatids, all nuclear areas stained with Hoechst 33258, while the 3 other techniques labeled either all or species-specific parts of the condensed chromatin. The reasons for these variable reactions are discussed in terms of technique specificities, DNA configuration and nucleoprotein moiety replacements.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00340875
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  • 51
    Digitale Medien
    Digitale Medien
    Pineal-retinal relationships: rhythmic biosynthesis and immunocytochemical localization of melatonin in the retina of the pike (Esox lucius) (1991)
    Springer
    Cell & tissue research 265 (1991), S. 601-609 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Retina ; Melatonin ; Rhythmic biosynthesis ; Immunocytochemistry ; Pike, Esox lucius (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The levels of melatonin and the activities of two enzymes of the melatonin biosynthetic pathway, serotonin N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT), were measured throughout the light-dark cycle in the retina of a teleost fish, the pike. HIOMT activity did not display significant variations, whereas NAT activity and melatonin content showed a daily rhythm, high levels occurring during the night. The profiles of the latter two rhythms did not closely match one another and differed from those previously described in the pineal organ of the same species. These results are discussed with respect to a possible paracrine role of retinal melatonin. Melatonin-like immunoreactivity was found in the photoreceptor cell layer and in the Müller cells of the inner nuclear layer. The intensity of the melatonin-like immunoreactivity varied throughout the 24 h light-dark cycle, in good correlation with the variations in the melatonin level as measured by radioimmunoassay.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00340884
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  • 52
    Digitale Medien
    Digitale Medien
    Immunocytochemical evidence of a met-enkephalin-like substance in the dense-core granules of mouse Merkel cells (1991)
    Springer
    Cell & tissue research 265 (1991), S. 611-614 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Immunocytochemistry ; Met-enkephalin ; Merkel cells ; Dense-core granules ; Mouse (ICR)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The electron-microscopic immunogold method was applied to Merkel cells of adult mice to demonstrate the subcellular localization of met-enkephalin-like immunoreactivity. Post-embedding incubation with metenkephalin antisera showed that the gold particles were associated with the dense-core granules of the Merkel cells. The majority, but not all, of the dense-core granules were strongly labelled. Osmication caused a significant reduction in the number of gold particles on these granules. The nerve terminal associated with the Merkel cell did not show met-enkephalin-like immunoreactivity. To the best of our knowledge, this is the first report of the ultrastructural localization of a positive met-enkephalin immunoreactivity in the dense-core granules of Merkel cells in mice.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00340885
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  • 53
    Digitale Medien
    Digitale Medien
    Generation of monoclonal antibodies detecting specific epitopes in olfactory and respiratory epithelia (1991)
    Springer
    Cell & tissue research 266 (1991), S. 247-258 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Monoclonal antibodies ; Immunocytochemistry ; Olfactory epithelium ; Respiratory epithelium ; Antigens ; (Rat Wistar) ; (Mouse BALB/c)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Two panels of monoclonal antibodies have been generated, each panel having a distinct specificity for antigens located in the ciliary zone of either the olfactory or respiratory epithelium of rats. Tissue specificity was confirmed in enzyme-linked immunosorbent assays on membrane fractions from various tissues. During ontogeny, the expression of olfactory-specific antigens preceeds that of respiratory-specific antigens; this observation correlates with differences in the genesis of the respective cilia type and confirms that different molecular entities are recognized. A spatial segregation of immunoreactivity in the chemosensory epithelium was observed for one of the olfactory-specific monoclonal antibodies; negative zones were located in the dorsal recess of the nasal cavity and on the tips of the turbinates. Olfactory-specific antibodies reacted with distinct polypeptide bands on Western blots from olfactory ciliary preparations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318180
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  • 54
    Digitale Medien
    Digitale Medien
    Identification of neuroendocrine cells producing a diuretic hormone in the tobacco hornworm moth, Manduca sexta (1991)
    Springer
    Cell & tissue research 266 (1991), S. 359-364 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Immunocytochemistry ; Neuropeptide ; Diuretic hormone ; Neurosecretion ; Manduca sexta, Eurema nicippe (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Separate antisera were raised to the N- and C-terminal half of the diuretic hormone from Manduca sexta. Antisera against the two halves of this peptide recognized the same cells in M. sexta, and preabsorption of the antisera with the peptides used as antigens abolished the immunoreactivity, confirming their specificity. The antisera reacted with two median neurosecretory cells on each side of the protocerebral groove in larvae, and with a group of about 80 small median neurosecretory cells in the adult, as well as their axons to, and their axon terminals in, the corpora cardiaca. During the early pupal stages, small cells, which are possibly derived from a common neuroblast, differentiate into immunoreactive neurosecretory cells, which explains the large increase in cell numbers in the adult. In the sleepy sulphur butterfly, Eurema nicippe, homologous median neurosecretory cells in the adult were immunoreactive with both antisera.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318191
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  • 55
    Digitale Medien
    Digitale Medien
    Comparative anatomy of pigment-dispersing hormone-immunoreactive neurons in the brain of orthopteroid insects (1991)
    Springer
    Cell & tissue research 266 (1991), S. 343-357 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Pigment-dispersing hormone ; Orthopteroid insects ; Immunocytochemistry ; Insect brain ; Periplaneta americana, Schistocerca gregaria, Teleogryllus commodus (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In a comparative study, the anatomy of neurons immunoreactive with an antiserum against the crustacean β-pigment-dispersing hormone was investigated in the brain of several orthopteroid insects including locusts, crickets, a cockroach, and a phasmid. In all species studied, three groups of neurons with somata in the optic lobes show pigment-dispersing hormone-like immunoreactivity. Additionally, in most species, the tritocerebrum exhibits weak immunoreactive staining originating from ascending fibers, tritocerebral cells, or neurons in the inferior protocerebrum. Two of the three cell groups in the optic lobe have somata at the dorsal and ventral posterior edge of the lamina. These neurons have dense ramifications in the lamina with processes extending into the first optic chiasma and into distal layers of the medulla. Pigment-dispersing hormone-immunoreactive neurons of the third group have somata near the anterior proximal margin of the medulla. These neurons were reconstructed in Schistocerca gregaria, Locusta migratoria, Teleogryllus commodus, Periplaneta americana, and Extatosoma tiaratum. The neurons have wide and divergent arborizations in the medulla, in the lamina, and in several regions of the midbrain, including the superior and inferior lateral protocerebrum and areas between the pedunculi and α-lobes of the mushroom bodies. Species-specific differences were found in this third cell group with regard to the number of immunoreactive cells, midbrain arborizations, and contralateral projections, which are especially prominent in the cockroach and virtually absent in crickets. The unusual branching patterns and the special neurochemical phenotype suggest a particular physiological role of these neurons. Their possible function as circadian pacemakers is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318190
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  • 56
    Digitale Medien
    Digitale Medien
    Immunocytochemical analysis of the cytoskeleton of the human amniotic epithelium (1991)
    Springer
    Cell & tissue research 266 (1991), S. 385-389 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Amniotic epithelium ; Cytoskeleton ; Filaments ; α-Actinin ; Ezrin ; Immunocytochemistry ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The amniotic epithelium constitutes a diffusion barrier controlling the passage of solutes and water between the aminotic cavity and maternal circulation. With the present immunocytochemical approach, we have shown that several major components of the cytoskeleton, i.e., actin, α-actinin, spectrin and ezrin, are preferentially associated with the apical and lateral cell surfaces of the human amniotic epithelium. Keratins are distributed throughout the entire cytoplasm, whereas vimentin mainly forms a perinuclear scaffold. These findings indicate a role of the various components of the cytoskeleton in the structural integrity and modulation of cell shape and junctional permeability.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318194
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  • 57
    Digitale Medien
    Digitale Medien
    Ultrastructure of melatonin-responsive cells in the ovine pars tuberalis (1991)
    Springer
    Cell & tissue research 263 (1991), S. 529-534 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Melatonin ; Pituitary gland, pars tuberalis ; Secretory cells ; Cyclic AMP ; Ultrastructure ; Cell culture ; Sheep
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Functional receptors for melatonin have been localized and characterized on the pars tuberalis (PT) of a number of mammalian species, but the cell-type responsive to melatonin is unknown. The ultrastructure of the ovine pars tuberalis has been examined and these findings correlated with the functional response of the gland to melatonin. This study revealed that two secretory cell types predominate in the ovine PT, which differ in the abundance of dense-core granules. The most abundant of the cells are either agranular or very sparsely granulated and represent 90% of the total population, with the remaining 10% being composed of cells with abundant dense-core vesicles. Few follicular cells were observed. This ratio of secretory cell-types persisted in primary culture, with the two types non-separable by Percoll gradient centrifugation. Using forskolin, as a non-specific stimulant of adenylate cyclase, melatonin was shown to inhibit the formation of cyclic AMP by 80–90% in cells both before and after Percoll centrifugation. The results demonstrate that the agranular secretory cells of the ovine pars tuberalis are the melatonin responsive cell-type of this gland.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00327285
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  • 58
    Digitale Medien
    Digitale Medien
    Immunocytochemical and ultrastructural characterization of endocrine cells in chicken proventriculus (1991)
    Springer
    Cell & tissue research 263 (1991), S. 541-548 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Proventriculus ; Endocrine secretory cells ; Secretory granules ; Peptide hormones ; Colocalization ; Immunocytochemistry ; Colloidal gold ; Chicken
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The endocrine cells of the chicken proventriculus were investigated immunocytochemically, using the peroxidase-antiperoxidase technique on paraffin and semithin sections for light microscopy, and immunogold staining in osmium-fixed material for electron microscopy. The fixation procedure also allowed a detailed ultrastructural investigation. Twenty-three antisera were tested and 7 immunoreactive cell-types were identified: D-cells containing somatostatin-like peptide; EG-cells immunoreactive to anti-glucagon, anti-GLP1 and antineurotensin; NT-cells labelled only with anti-neurotensin; BN-cells containing bombesin-like material; ENK-cells showing met-enkephalin immunoreactivity; EC-cells reactive to anti-serotonin; and APP-cells positive to anti-avian pancreatic polypeptide. In addition, enterochromaffin-like (ECL) cells, were also detected by electron microscopy. The presence of ENK-cells and the ultrastructure of these and NT-cells are described for the first time in chicken proventriculus, and glucagon, GLP1 and neurotensin are shown to be colocalized in the EG-cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00327287
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  • 59
    Digitale Medien
    Digitale Medien
    An histological and immunocytochemical study of the neuroendocrine cells in the intestine of Podarcis hispanica Steindachner, 1870 (Lacertidae) (1991)
    Springer
    Cell & tissue research 263 (1991), S. 549-556 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Neuroendocrine cells ; Intestine ; Chromogranin ; Serotonin ; Regulatory peptides ; Immunocytochemistry ; Podarcis hispanica (Reptilia, Lacertilia)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Numerous endocrine cells can be observed in the gut of the lizard Podarcis hispanica after application of the Grimelius silver nitrate technique. The argyrophilic endocrine cells are usually tall and thin in the small intestine but short, basal, and round in the large intestine. Eleven types of immunoreactive endocrine cells have been identified by immunocytochemical methods. Numerous serotonin-, caerulein/gastrin/cholecystokinin octapeptide-and peptide tyrosine-tyrosine-immunoreactive cells; a moderate number of pancreatic polypeptide-, neurotensin-, somatostatin-, glucagon-like peptide-1-and glucagon-immunoreactive cells, and few cholecystokinin N-terminal-and bombesin-immunoreactive cells were found in the epithelium of the small intestine. Coexistence of glucagon with GLP-1 or PP/PYY has been observed in some cells. In the large intestine a small number of serotonin-, peptide tyrosine-tyrosine-, pancreatic polypeptide-, neurotensin-, somatostatin-and glucagon-like peptide-1-immunoreactive cells were detected. Vasoactive intestinal peptide immunoreactivity was found in nerve fibers of the muscular layer. Substance P-immunoreactive nerve fibers were detected in lamina propria, submucosa and muscular layer. Chromogranin A-immunoreactive cells were observed throughout the intestine, although in lower numbers than argyrophilic cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00327288
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  • 60
    Digitale Medien
    Digitale Medien
    Ultrastructure and distribution of somatostatin-like immunoreactive neurons and nerve fibres in the coeliac ganglion of cats (1991)
    Springer
    Cell & tissue research 263 (1991), S. 567-572 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Somatostatin ; Coeliac ganglion ; Autonomic innervation ; Ultrastructure ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Somatostatin-like immunoreactivity was localized in nerve cell bodies and nerve terminals in the cat coeliac ganglion. Two types of somatostatin-immunoreactive cell bodies were revealed, the first being large (diameter 35 μm), numerous and weakly labelled, where—as the second was considerably smaller (diameter 10.4 μm), sparsely distributed and heavily stained. The immunoreactive nerve terminals were in synaptic contact with many immunonegative large neurons and dendrites. However, in a few cases, somatostatin-immunoreactive nerve terminals could also be observed on the surface of lightly stained neurons. Transection of vagal or mesenteric nerve failed to affect the distribution or density of somatostatin-like immunoreactive nerve terminals. These results demonstrate the existence of a synaptic input to the principal neurons of the coeliac ganglion of the cat by somatostatin-containing nerve terminals and suggest that this peptide may act as a neuromodulator or neurotransmitter. It is proposed that somatostatin-positive neurons provide intrinsic projections to other somatostatin-positive and to somatostatin-negative neurons throughout the coeliac ganglion, thereby creating a complex interneuronal system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00327290
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  • 61
    Digitale Medien
    Digitale Medien
    Islets of preadipocytes highly committed to differentiation in cultures of adherent rat adipocytes (1991)
    Springer
    Cell & tissue research 264 (1991), S. 243-251 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Preadipocytes ; Adipocyte precursor cells ; Adipose tissue ; Differentiation-cell cultures ; Ultrastructure ; Rat (Fischer 344)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Cultures of adherent mature adipocytes, obtained from collagenase-digests of adipose tissue of the rat, invaribly contain rapidly proliferating, fibroblastlike cells despite the washing and centrifugation procedures empolyed during isolation of the fat cells. Such spindle-like cells originate from low-density structures, which we term “islets”, that are present, together with the mature adipocytes, in the floating layer of the digest of adipose tissue. Islets are found in preparations from adult (3–4 months old) as well as aging (17–24 months old) rats. By light-and electron microscopy, the islets appear as clusters of closely associated cells containing a variable amount of lipid-like material. Cells of endothelial or pericytic origin are also present in the islets. Within a few hours of culture, the islets give rise to those spindle-like cells that have been seen to proliferate in the cultures. By 36–48 hours, such cells begin to accumulate lipid droplets and, by 150 hours, assume the morphology of small mature adipocytes (diameter 20–35 μm) with a large central lipid droplet. The pattern of differentiation of these cells recalls that of preadipocytes derived from the stromal-vascular fraction of adipose tissue digests. Nonetheless, the extent and rapidity of their adipose conversion, as well as the culture conditions necessary for differentiation, are different and suggest that these cells are a substantially uniform subpopulation of adipocyte-precursor cells highly committed to differentiation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00313961
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  • 62
    Digitale Medien
    Digitale Medien
    Changes in glial fibrillary acidic protein and karyotype during culturing of two cell lines established from human glioblastoma multiforme (1991)
    Springer
    Cell & tissue research 265 (1991), S. 73-81 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Gliobastoma multiforme ; Cell culture ; Glial fibrillary acidic protein ; Immunocytochemistry ; Cytogenetics ; Man
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Two human cell lines (GL15 and GL22) derived from glioblastoma multiforme were established and characterized by immunohistochemical and cytogenetic techniques. The expression of glial fibrillary acidic proteins and the karyotype were analyzed at different passages for both cell lines. The course of marker-pattern differed in the two cell lines. The main findings were a cell-density-dependent expression of glial fibrillary acidic protein in the cell line GL15 at all passages and a decreased expression of this protein over time in the cell line GL22. Both cell lines had hyperdiploid karyotypes and exhibited glioma-specific chromosomal abnormalities (gain of chromosome 7 and loss of chromosome 10). In the GL15 cell line no relevant chromosomal changes were produced during culturing, whereas in the GL22 cell line a hypodiploid clone appeared at the 42nd passage. The immunohistochemical and cytogenetic data resulting from this study confirm that the two cell lines established in our laboratory originated from astrocytic tumor cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318141
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  • 63
    Digitale Medien
    Digitale Medien
    Postnatal changes in the ultrastructure of the rat olfactory epithelium: the supranuclear region of the supporting cells (1991)
    Springer
    Cell & tissue research 265 (1991), S. 193-196 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Postnatal development ; Olfactory epithelium ; Supporting cells ; Receptor cell dendrites ; Ultrastructure ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The present electron-microscopical study reports ultrastructural changes occurring in the supranuclear region of the supporting cells of the rat olfactory epithelium during the first 16 days of postnatal life. These changes are concerned with the enclosure of receptor cell dendrites and an increase in the amount of smooth endoplasmic reticulum, which has a specific distribution in the supporting cell. An increase in microvillous projections at the free cell surface is also observed. Moreover, this report demonstrates that the cytoarchitecture of the apical portion of the olfactory epithelium at the 16th day of postnatal life is similar, with respect to the relationship between supporting cells and receptor cell dendrites, to that of adult animals.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318154
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  • 64
    Digitale Medien
    Digitale Medien
    Pituitary adenylate cyclase-activating peptide (PACAP), a new vasoactive intestinal peptide (VIP)-like peptide in the respiratory tract (1991)
    Springer
    Cell & tissue research 265 (1991), S. 197-201 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Pituitary adenylate cyclase-activating peptide (PACAP) ; Vasoactive intestinal peptide (VIP) ; Immunocytochemistry ; Respiratory tract ; Autonomic innervation ; Mammals
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Pituitary adenylate cyclase-activating peptide (PACAP) is a vasoactive intestinal peptide (VIP)-like peptide recently isolated from ovine hypothalami. Nerve fibers displaying PACAP immunoreactivity were found in the respiratory tract of rats, guinea pigs, ferrets, pigs, sheep and squirrel monkeys. A moderate supply of PACAP-immunoreactive fibers was seen in the nasal mucosa of guinea pigs. Few to moderate numbers of PACAP-containing fibers occurred in the tracheo-bronchial wall of rats, guinea pigs, ferrets, pigs, sheep and squirrel monkeys. The fibers were distributed beneath the epithelium, around blood vessels and seromucous glands, and among bundles of smooth muscle. In the lungs, the immunoreactive fibers were observed close to small bronchioli. A few PACAP-immunoreactive nerve cell bodies were seen in the sphenopalatine and otic ganglia of guinea pigs. Simultaneous double immunostaining of the respiratory tract of sheep and ferrets revealed that all PACAP-containing nerve fibers stored VIP. We suggest that neuronal PACAP may take part in the regulation of smooth muscle tone and glandular secretion.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318155
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  • 65
    Digitale Medien
    Digitale Medien
    Differences in the immunoreactivity to phenylethanolamine-N-methyltransferase in the central adrenergic neurons of four strains of rats (1991)
    Springer
    Cell & tissue research 265 (1991), S. 307-315 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Brain, vertebrate ; Phenylethanolamine-N-methyltransferase ; Adrenaline ; Immunocytochemistry ; HPLC ; Rat (Wistar, Sprague-Dawley, Long Evans, Zucker)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Immunocytochemistry was used to compare the immunoreactivity of adrenergic neurons to a well characterized specific immunoserum to phenylethanolamine-N-methyltransferase (PNMT) in different strains of rats commonly used in research studies. In adult animals, marked differences were found in the PNMT-immunoreactivity of neurons between Wistar rats and other strains, resulting in a lower PNMT-immunostaining intensity (i) within neuronal perikarya of the medulla oblongata, and (ii) more strikingly, within nerve fibers and terminals located in various brain regions. This low PNMT-immunoreactivity of nerve fibers was detected both in 14- and 35-day-old Wistar rats. On the other hand, the HPLC measurement of catecholamines, in particular of adrenaline in the hypothalamus and the medulla oblongata, did not show any difference between adult Wistar and Sprague-Dawley rats. These data suggest that the low PNMT-immunoreactivity observed in central adrenergic neurons of the Wistar rats is related to the poor recognition of the antigen by the PNMT-antibody used. Possibly, these nerve cells mainly display an isoform of the enzyme that is immunologically different from the PNMT contained within the adrenergic neurons of other rat strains.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00398078
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  • 66
    Digitale Medien
    Digitale Medien
    Diversity of ultrastructure in different phenotypes of cultured microvessel endothelial cells isolated from bovine corpus luteum (1991)
    Springer
    Cell & tissue research 266 (1991), S. 37-49 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Microvessel endothelial cells ; Cell culture ; Corpus luteum ; Ultrastructure ; Cow
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Five different types of cultured microvessel endothelial cells defined by use of light microscopy and scanning electron microscopy in a preceding study were investigated by transmission electron microscopy. Type-1 cells displayed a deep invagination of the cell membrane or a single cilium. Granules of low electron density were abundant. A perinuclear ring of intermediate filaments occurred. Cultures of type-2 cells were subdivided into phenotype A, reminiscent of cell-type 1, and into phenotype B, assumed to be vascular smooth muscle cells. Many highly electron-dense granules appeared in late postconfluent cultures of both phenotypes. Cell-type 3 was conspicuous because of a large intracytoplasmic vacuole. Lysosomes with curvilinear bodies were found in cell-types 3 and 4. Both cell types developed a peripheral regular network of microfilaments. Cell-type 5 showed vesiculation of the rough endoplasmic reticulum, lipid droplets and a peripheral felt-like belt of microfilaments. Tubular forms seen in late postconfluent cultures of cell-types 1 to 3 displayed a core of extracellular matrix. Pseudotubular forms of cell-type 4 contained apoptotic bodies. Thus, as seen at the ultrastructural level, different features are maintained by cultured microvessel endothelial cells, suggesting that they have different inherent properties.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00678709
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  • 67
    Digitale Medien
    Digitale Medien
    Immunohistochemical distribution of simple-epithelial-type keratins and other intermediate filament proteins in the developing human pituitary gland (1991)
    Springer
    Cell & tissue research 266 (1991), S. 59-64 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Pituitary gland ; Rathke's pouch ; Intermediate filaments ; Cytokeratins ; Development, ontogenetic ; Immunocytochemistry ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary An immunohistochemical study of the production of the intermediate filaments [vimentin, cytokeratin, and glial filament acidic protein (GFAP)] during development of the pituitary gland was made by use of fetal and adult human pituitary tissue. Among these intermediate filament proteins in the anterior and intermediate lobes of the pituitary, cytokeratin is the first to appear, followed by GFAP and vimentin. However, only cytokeratin is seen during the period of morphogenesis of the pituitary gland, with the type-II subfamily cytokeratin 8 being the earliest to appear. Among the simple-epithelial-type cytokeratins, cytokeratins 8 and 19 were observed within the pituitary primordium during morphogenesis. Cells immunoreactive for cytokeratins 8 and 19 showed a heterogeneous three-dimensional distribution pattern in Rathke's pouch. Both cytokeratins 8 and 19 tended to be strongly positive at sites in the pituitary primordium where cells had become more loosely arranged (i.e., areas far from the diencephalon) but were only weakly positive in areas in which the epithelial cells were densely packed (i.e., areas closely associated with the diencephalon). It is concluded that, during the period of morphogenesis, Rathke's pouch has the intermediate filaments characteristic of simple epithelium and shows different immunoreactivity for simple-epithelial-type cytokeratins from place to place according to the extent of cellular differentiation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00678711
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  • 68
    Digitale Medien
    Digitale Medien
    Morphology of the granular hemocytes of the Japanese horseshoe crabTachypleus tridentatus and immunocytochemical localization of clotting factors and antimicrobial substances (1991)
    Springer
    Cell & tissue research 266 (1991), S. 137-147 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Clotting factors ; Antimicrobial substances ; Hemocytes ; Immunocytochemistry ; Tachypleus tridentatus (Chelicerata)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The structure of hemocytes in the normal state and during blood coagulation, and the intracellular localization of three clotting factors and two antimicrobial factors were examined in the Japanese horseshoe crabTachypleus tridentatus. Two types of hemocytes were found in the circulating blood: non-granular and granular hemocytes. The latter contained numerous dense granules classed into two major types: L- and D-granules. The L-granules were larger (up to 1.5 μm in diameter) and less electron-dense than the D-granules (less than 0.6 μm in diameter). The L-granules contained three clotting factors and one antimicrobial factor, whereas the D-granules exclusively contained the other antimicrobial factor. After treatment with endotoxin, the L-granules were released more rapidly than the D-granules, although almost all granules were finally exocytosed. The granular hemocyte possessed a single Golgi complex; possible precursor granules of L-granules and D-granules contained tubular and condensed dense material, respectively. These data are discussed in relation to the self-defense mechanisms of the horseshoe crab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00678720
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  • 69
    Digitale Medien
    Digitale Medien
    Differential production and regulation of gonadotropins (GTH I and GTH II) in the pituitary gland of rainbow trout, Oncorhynchus mykiss, during ovarian development (1991)
    Springer
    Cell & tissue research 266 (1991), S. 457-467 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Gonadotropin ; Gonadotropin subunits ; Gonadotropes ; In situ hybridization ; Immunocytochemistry ; Pituitary gland, pars distalis ; Oogenesis ; Oncorhynchus mykiss (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Biosynthesis of salmon gonadotropins, GTH I and GTH II, during ovarian development, were examined by means of in situ hybridization histochemistry and indirect immunocytochemistry. In rainbow trout pituitary glands, expression of GTH Iβ- and IIβ-subunit genes appeared separately in distinct cells (GTH I- and GTH II-cells), whereas the GTH α-subunit gene was expressed in both cell-types. In the GTH I-cells, coordinated increases in GTh, α and Iβ messenger ribonucleic acids (mRNAs) occurred coincident with the onset of vitellogenesis, indicating active synthesis of GTH I during vitellogenesis. In contrast, in the GTH II-cells, both GTH α-and IIβ-mRNA signals markedly increased from a later stage of vitellogenesis and persisted throughout oocyte maturation and ovulation, supporting the idea that GTH II is actively synthesized as a maturational GTH. GTH α-mRNA levels in the GTH I-cells selectively decreased prior to final oocyte maturation, although Iβ-mRNA levels remained elevated, thus suggesting a decline of biosynthesis of GTH I after vitellogenesis. These findings clarify how the synthesis of GTH I and GTH II are coordinated in the piscine pituitary, and indicate that the expression of GTH subunit genes during gametogenesis is regulated differentially in a cell-specific manner, both temporally and spatially.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318586
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  • 70
    Digitale Medien
    Digitale Medien
    Pigment-dispersing hormone-immunoreactive neurons and their relation to serotonergic neurons in the blowfly and cockroach visual system (1991)
    Springer
    Cell & tissue research 266 (1991), S. 511-523 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Visual system ; Neuropeptides ; Serotonin ; Pigment-dispersing hormone ; Immunocytochemistry ; Neuromodulators ; Phormia terraenovae (Insecta) ; Leucophaea maderae (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The pigment-dispersing hormone (PDH) family of neuropeptides comprises a series of closely related octadecapeptides, isolated from different species of crustaceans and insects, which can be demonstrated immunocytochemically in neurons in the central nervous system and optic lobes of some representatives of these groups (Rao and Riehm 1989). In this investigation we have extended these immunocytochemical studies to include the blowfly Phormia terraenovae and the cockroach Leucophaea maderae. In the former species tissue extracts were also tested in a bioassay: extracts of blowfly brains exhibited PDH-like biological activity, causing melanophore pigment dispersion in destalked (eyestalkless) specimens of the fiddler crab Uca pugilator. Using standard immunocytochemical techniques, we could demonstrate a small number of pigment-dispersing hormone-immunoreactive (PDH-IR) neurons innervating optic lobe neuropil in the blowfly and the cockroach. In the blowfly the cell bodies of these neurons are located at the anterior base of the medulla. At least eight PDH-IR cell bodies of two size classes can be distinguished: 4 larger and 4 smaller. Branching immunoreactive fibers invade three layers in the medulla neuropil, and one stratum distal and one proximal to the lamina synaptic layer. A few fibers can also be seen invading the basal lobula and the lobula plate. The fibers distal to the lamina appear to be derived from two of the large PDH-IR cell bodies which also send processes into the medulla. These neurons share many features in their laminamedulla morphology with the serotonin immunoreactive neurons LBO-5HT described earlier (see Nässel 1988). It could be demonstrated by immunocytochemical double labeling that the serotonin and PDH immunoreactivities are located in two separate sets of neurons. In the cockroach optic lobe PDH-IR processes were found to invade the lamina synaptic region and form a diffuse distribution in the medulla. The numerous cell bodies of the lamina-medulla cells in the cockroach are located basal to the lamina in two clusters. Additional PDH-IR cell bodies could be found at the anterior base of the medulla. The distribution and morphology of serotonin-immunoreactive neurons in the cockroach lamina was found to be very similar to the PDH-IR ones. It is hence tempting to speculate that in both species the PDH-and serotonin-immunoreactive neurons are functionally coupled with common follower neurons. These neurons may be candidates for regulating large numbers of units in the visual system. In the flies photoreceptor properties may be regulated by action of the two set of neurons at sites peripheral to the lamina synaptic layer, possibly by paracrine release of messengers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318593
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  • 71
    Digitale Medien
    Digitale Medien
    Effect of cytokines on thymic hematopoietic precursors (1991)
    Springer
    Cell & tissue research 264 (1991), S. 369-375 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Thymus ; CD4- ; CD8- ; thymocyte ; Thymic hematopoietic precursors ; Cytokines ; Ultrastructure ; Mouse (DBA/2, H-2d)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary We have previously shown that the interaction of thymocytes with thymic accessory cells (macrophages and/or interdigitating cells) is one of the factors required for thymocyte activation. Precursors of both thymic accessory cell and thymocytes are included in the CD4- CD8- Mac-1- Ia- subpopulation, and their respective maturation and/or activation may be modulated by granulocyte-macrophage colony-stimulating factor, interleukin 1 and interleukin 2. When CD4- CD8- thymic cells are activated with granulocyte-macrophage colony-stimulating factor plus interleukin 2, both macrophages and interdigitating-like cells are present, as shown by electron microscopy. When activated with interleukin 1 plus interleukin 2, the interdigitating-like cells is the only accessory cell present. In both culture conditions, large clusters are formed between interdigitating cells and lymphoid cells. These results have led us to propose two-step signals for thymocyte proliferation: first, the maturation of macrophages under granulocyte-macrophage colony-stimulating factor control and the production of interleukin 1, and secondly, the maturation of interdigitating cells under interleukin 1 control, their clustering with thymocytes which are then activated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00313976
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  • 72
    Digitale Medien
    Digitale Medien
    The distribution of corticotropin-releasing factor-immunoreactive neurons and nerve fibers in the brain of the snake, Natrix maura (1991)
    Springer
    Cell & tissue research 264 (1991), S. 539-548 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Corticotropin-releasing factor (CRF) ; Immunocytochemistry ; Arginine vasotocin (AVT) ; Mesotocin (MST) ; Co-localization ; Natrix maura (Serpentes)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The anatomical distribution of neurons and nerve fibers containing corticotropin-releasing factor (CRF) has been studied in the brain of the snake, Natrix maura, by means of immunocytochemistry using an antiserum against rat CRF. To test the possible coexistence of CRF with the neurohypophysial peptides arginine vasotocin (AVT) and mesotocin (MST) adjacent sections were stained with antisera against the two latter peptides. CRF-immunoreactive (CRF-IR) neurons exist in the paraventricular nucleus (PVN). In some neurons of the PVN, coexistence of CRF with MST or of CRF with AVT has been shown. Numerous CRF-IR fibers run along the hypothalamo-hypophysial tract and end in the outer layer of the median eminence. In addition, some fibers reach the neural lobe of the hypophysis. CRF-IR perikarya have also been identified in the following locations: dorsal cortex, nucleus accumbens, amygdala, subfornical organ, lamina terminalis, nucleus of the paraventricular organ, nucleus of the oculomotor nerve, nucleus of the trigeminal nerve, and reticular formation. In addition to all these locations CRF-IR fibers were also observed in the lateral septum, supraoptic nucleus, habenula, lateral forebrain bundle, paraventricular organ, hypothalamic ventromedial nucleus, raphe and interpeduncular nuclei.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319043
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  • 73
    Digitale Medien
    Digitale Medien
    The complex-type glycoprotein secreted by the bovine subcommissural organ: an immunological study using C1B8A8 monoclonal antibody (1991)
    Springer
    Cell & tissue research 266 (1991), S. 483-490 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Subcommissural organ ; Secretory pathway ; C1B8A8 monoclonal antibody ; Immunocytochemistry ; Immunoaffinity chromatography ; Bovine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The secretory pathway of the complex-type glycoprotein specific to the subcommissural organ (SCO) was examined using the monoclonal antibody (Mab) C1B8A8. Immunoreactive material was revealed in various compartments of the secretory ependymocyte, i.e., the endoplasmic reticulum, the Golgi area and the secretory vacuoles. In addition, immunoreactive material was also observed in the ventricular cavity. Evidence of a release both at the apical lining and at the basal process of the SCO ependymocytes suggests that the same protein could be secreted into the cerebrospinal fluid and the perivascular spaces. After immunoaffinity chromatography of soluble extracts of the SCO on Mab C1B8A8 immunoadsorbent columns, three glycopeptides were identified on Western blots; they were concanavalin A (Con A)-positive (88, 54 and 34 kDa) and wheat-germ agglutinin (WGA)-positive (54 and 34 kDa). The Con A-positive glycopeptide (88 kDa) is probably related to the high-mannose-type glycoprotein, the precursor form of the secreted compound, whereas the 54 kDa-glycopeptide that is both Con A- and WGA-positive could represent an intermediate form. The 34 kDa-glycopeptide that is strongly WGA-positive could be related to the monomeric form of the secreted compound. These three glycopeptides were not revealed in eluted fractions of soluble extracts of the ependyma that served as control.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318589
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  • 74
    Digitale Medien
    Digitale Medien
    Distribution of aromatase-immunoreactive cells in the mouse forebrain (1991)
    Springer
    Cell & tissue research 263 (1991), S. 71-79 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Aromatase ; Immunocytochemistry ; Brain aromatase ; Preoptic area ; Hypothalamus ; Mouse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of aromatase-immunoreactive cells was studied by immunocytochemistry in the mouse forebrain using a purified polyclonal antibody raised against human placental aromatase. Labeled perikarya were found in the dorso-lateral parts of the medial and tuberal hypothalamus. Positive cells filled an area extending between the subincertal nucleus in the dorsal part, the ventromedial hypothalamic nucleus in the ventral part, and the internal capsule and the magnocellular nucleus of the lateral hypothalamus in the lateral part. The same distribution was seen in the two strains of mice that were studied (Jackson and Swiss), and the number of immunoreactive perikarya did not seem to be affected by castration or testosterone treatment. No immunoreactivity could be detected in the medial regions of the preoptic area and hypothalamus; these were expected to contain the enzyme based on assays of aromatase activity performed in rats and on indirect autoradiographic evidence in mice. Our data raise questions concerning the distribution of aromatase in the brain and the mode of action of the centrally produced estrogens.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318401
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  • 75
    Digitale Medien
    Digitale Medien
    An immunocytochemical study of the endocrine pancreas in the Australian fat-tailed dunnart (Sminthopsis crassicaudata) (1991)
    Springer
    Cell & tissue research 263 (1991), S. 195-198 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Pancreas, endocrine ; Islets of Langerhans ; Immunocytochemistry ; Endocrine cells four types ; Electron microscopy ; Sminthopsis crassicaudata (Marsupialia)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The endocrine pancreas of the Australian fattailed dunnart, Sminthopsis crassicaudata, was investigated by means of electron-microscopic immunocytochemistry using the protein A-gold technique on London resin (LR) white-embedded tissue. The primary antibodies used were raised against insulin, glucagon, somatostatin and pancreatic polypeptide. The morphology of the secretory granules differed in the four cell types. The insulin cells are pleomorphic, and the secretory granules composed of an electron-dense core surrounded by an electron-lucen halo. The glucago cells possess granules with an electron-dense core usually surrounded by a halo of less dense granular material. Somatostatin cells have large, less dense secretory granules. The pancreatic polypeptide cells show small, dense secretory granules. In order for an ultrastructural study to be considered reliable for the definite identification of endocrine cell types, it is essential that it be corroborated by immunocytochemical data at the light-or preferably electron-microscopic level. Recent developments in immuno-electron-microscopic techniques have contributed to a better knowledge of cells responsible for the secretion of a wide variety of hormones, as in this study.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318415
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  • 76
    Digitale Medien
    Digitale Medien
    Localization of hydroxyindole O-methyltransferase-synthesizing cells in bovine epithalamus: immunocytochemistry and in-situ hybridization (1991)
    Springer
    Cell & tissue research 263 (1991), S. 413-418 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Pineal organ ; Epithalamus ; Pinealocytes ; Hydroxyindole O-methyltransferase (HIOMT) ; Immunocytochemistry ; HIOMT-mRNA ; In-situ hybridization ; Bovine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Hydroxyindole O-methyltransferase (HIOMT)-immunoreactive cells and melatonin synthesis were demonstrated in bovine epithalamus (including the pineal gland) with monoclonal antibodies and cRNA probes to HIOMT. The HIOMT-immunoreactive product was present in the cytoplasm of pinealocytes. All identifiable pinealocytes were clearly labeled in the pineal gland. The expression of the HIOMT gene was first identified in pinealocyte cytoplasm by in-situ hybridization (ISH). The distribution of the hybridization-positive cells in the pineal gland was compatible with that revealed by immunocytochemistry using the monoclonal antibody to HIOMT. In addition, HIOMT transcripts were found in the medial habenular nucleus, and the habenular and posterior commissure; they may correspond to S-antigen-immunoreactive cells demonstrated in the same regions of the hamster and the mouse. In these regions, the hybridization-positive cells did not exhibit HIOMT-immunoreactivity; thus, cells devoid of immunoreactivity may synthesize but rapidly transport the newly synthesized proteins. These results indicate (1) that the conversion of N-acetylserotonin into melatonin takes place in the cytoplasm of pinealocytes, (2) that some epithalamic cells in the habenular area may synthesize melatonin, and (3) that melatonin may act as a chemical messenger in centrally directed processes, as shown by using S-antigen immunocytochemistry.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00327275
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  • 77
    Digitale Medien
    Digitale Medien
    The fine structure of lamellate cells in the brain of amphioxus (Branchiostoma lanceolatum, Cephalochordata) (1991)
    Springer
    Cell & tissue research 263 (1991), S. 597-600 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Lamellate cell ; Ultrastructure ; Ciliary photoreceptors ; Nervous system, prochordates ; Branchiostoma lanceolatum (Acrania)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The lamellate cells of amphioxus have round nuclei, and cytoplasm with many mitochondria and a large amount of glycogen. Each of these cells projects a highly modified, branched cilium into the central canal, where it characteristically forms lamellar structures. Primary branches and secondary lamellae often contain accessory microtubules that are not derived from the axonema. The functional and evolutionary significance of this cell type is discussed in relation to the ciliary photoreceptors found in other chordates.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00327295
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  • 78
    Digitale Medien
    Digitale Medien
    Cell types in the fetal pars tuberalis of the human adenohypophysis at mid-gestation (1991)
    Springer
    Cell & tissue research 264 (1991), S. 161-165 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Adenohypophysis ; Pars tuberalis ; Ultrastructure ; Immunohistochemistry ; Fetal ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The pars tuberalis of the adenohypophysis was investigated in three human fetuses at mid-gestation by electron microscopy or immunohistochemistry. In addition to gonadotrophs and thyrotrophs, identified by immunohistochemistry and ultrastructural morphology, electron microscopy revealed the existence of an additional differentiated cell type closely resembling “pars tuberalis-specific” cells known from other species. The role of this cell type in the human endocrine regulation remains to be elucidated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00305734
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  • 79
    Digitale Medien
    Digitale Medien
    Nerve growth factor receptor-like immunoreactivity in primary and permanent canine tooth pulps of the cat (1991)
    Springer
    Cell & tissue research 264 (1991), S. 321-328 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Tooth pulp ; NGF receptor ; Calcitonin gene-related peptide ; Substance P ; Neuropeptide Y ; Immunocytochemistry ; Electron microscopy ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of nerve growth factor receptor (NGF receptor)-like immunoreactivity in pulps of developing primary and mature permanent cat canine teeth was examined, by use of a monoclonal antibody against NGF receptor detected by fluorescence immunohistochemistry and pre-embedding immunocytochemical light- and electron microscopy. Both primary and permanent pulps contained a vast number of NGF receptor-like immunoreactive nerves. Immunolabelling appeared to be localized both to axons and Schwann cells. In addition, many blood vessel walls in immature primary tooth pulps showed NGF receptor-like immunoreactivity, in contrast to permanent pulps where blood vessels rarely were NGF receptor-immunoreactive. Double-labelling immunofluorescence experiments revealed that in the permanent pulp a majority of the NGF receptor-positive nerves also showed calcitonin gene-related peptide (CGRP)-like immunoreactivity, and many showed substance P-like immunoreactivity. However, nerve fibers with neuropeptide Y-like immunoreactivity lacked NGF receptor-like immunoreactivity. In developing primary tooth pulps fewer NGF receptor-positive nerves were CGRP-like immunoreactive or substance P-like immunoreactive, as compared to the permanent pulp. Neuropeptide Y-like immunoreactive nerve fibers were not detected in the primary tooth pulp. The results suggest a role for nerve growth factor in both developing and mature sensory nerves of the tooth pulp.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00313969
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  • 80
    Digitale Medien
    Digitale Medien
    Identification of different types of serotonin-like immunoreactive olfactory interneurons in four infraorders of decapod crustaceans (1991)
    Springer
    Cell & tissue research 264 (1991), S. 357-362 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Serotonin ; Immunocytochemistry ; Olfactory interneurons ; Macrobrachium rosenbergii, Munida sarsi, Pacifastacus leniusculus (Crustacea)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary An antiserum raised against serotonin (5HT) was applied to the brains of representatives of four different infraorders of decapod crustaceans, and revealed two morphological classes of olfactory interneurons. They were classified by the position and size of their cell bodies, and by their connection pattern. One class consisted of giant olfactory interneurons and the other of globuli cells. They were regarded as input and intrinsic interneurons, respectively, because of their morphology. The two classes displayed a similar pattern in two of the infraorders, whereas only one class appeared in the other two infraorders.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00313974
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  • 81
    Digitale Medien
    Digitale Medien
    Inhibin-like and gonadotropin-like immunoreactivity in pituitary cells of male monkeys (Macaca fascicularis, Macaca mulatta) (1991)
    Springer
    Cell & tissue research 265 (1991), S. 203-209 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Inhibin ; LH ; FSH ; Pituitary gland, pars anterior ; Immunocytochemistry ; Maccaca fascicularis, Macaca mulatta (Primates)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Inhibin-like immunoreactivity was detected by immunocytochemistry in the pituitaries of untreated male crab-eating macaques (cynomolgus monkey) and rhesus monkeys, in rhesus monkeys actively immunized against FSH, and in one orchidectomized crab-cating macaque. Localizations were performed by the immunogold-silver staining with 5-nm colloidal gold-conjugated second or third antibodies and by the alkaline phosphatase-anti-alkaline-phosphatase technique. Two different inhibin-specific antisera, raised against the α-subunit or the entire inhibin molecule, provided identical staining patterns. Positive label was confined to the pars distalis of the pituitary and occurred exclusively in the cytoplasm of morphologically different cell types throughout the pars distalis in all pituitaries. Staining was most prominent in clusters of chromophobic cells. The presence of inhibin-like activity in the pituitary of an orchidectomized monkey with undetectable serum inhibin levels suggests that inhibin is produced within the pituitary gland. Co-localization studies for the β-subunits of the gonadotropic hormones revealed that on average 82% of the gonadotropes were bihormonal. Using the same protocol, co-localization of inhibin-like activity with gonadotropin-like immunoreactivity revealed only a small degree of common distribution (〈15%). Inhibinpositive cells were frequently in close proximity to gonadotropic cells and, thus, paracrine effects of inhibin on gonadotropin-synthesizing cells are conceivable.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00398068
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  • 82
    Digitale Medien
    Digitale Medien
    Localization of neuropeptide Y-immunoreactive cells and fibres in the brain of the Japanese quail (1991)
    Springer
    Cell & tissue research 265 (1991), S. 219-230 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Neuropeptide Y (NPY) ; Immunocytochemistry ; Avian brain ; Japanese quail, Coturnix coturnix japonica
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In the present study, we have demonstrated, by means of the biotin-avidin method, the widespread distribution of neuropeptide Y (NPY)-immunoreactive structures throughout the whole brain of the Japanese quail (Coturnix coturnix japonica). The prosencephalic region contained the highest concentration of both NPY-containing fibres and perikarya. Immunoreactive fibres were observed throughout, particularly within the paraolfactory lobe, the lateral septum, the nucleus taeniae, the preoptic area, the periventricular hypothalamic regions, the tuberal complex, and the ventrolateral thalamus. NPY-immunoreactive cells were represented by: a) small scattered perikarya in the telencephalic portion (i.e. archistriatal, neostriatal and hyperstriatal regions, hippocampus, piriform cortex); b) medium-sized cell bodies located around the nucleus rotundus, ventrolateral, and lateral anterior thalamic nuclei; c) small clustered cells within the periventricular and medial preoptic nuclei. The brainstem showed a less diffuse innervation, although a dense network of immunopositive fibres was observed within the optic tectum, the periaqueductal region, and the Edinger-Westphal, linearis caudalis and raphes nuclei. Two populations of large NPY-containing perikarya were detected: one located in the isthmic region, the other at the boundaries of the pons with the medulla. The wide distribution of NPY-immunoreactive structures within regions that have been demonstrated to play a role in the control of vegetative, endocrine and sensory activities suggests that, in birds, this neuropeptide is involved in the regulation of several aspects of cerebral functions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00398070
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  • 83
    Digitale Medien
    Digitale Medien
    Immunocytochemical distribution of FMRFamide-like substance in the brain of the cloudy dogfish, Scyliorhinus torazame (1991)
    Springer
    Cell & tissue research 265 (1991), S. 243-250 
    Details
    ISSN: 1432-0878
    Schlagwort(e): FMRFamide ; Brain, vertebrate ; Hypothalamus ; Pituitary gland, pars intermedia ; Nervus terminalis ; Immunocytochemistry ; Scyliorhinus torazame (Elasmobranchii)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of the molluscan cardioexcitatory tetrapeptide FMRFamide (Phe-Met-Arg-Phe-NH2) in the brain of the cloudy dogfish, Scyliorhinus torazame, was examined by immunocytochemistry. FMRFamide-like immunoreactivity was demonstrated to occur extensively in various regions of the dogfish brain, except for the corpus cerebelli. Immunoreactive neuronal perikarya were located in the ganglion of the nervus terminalis, the preoptic area, and the hypothalamic periventricular gray matter consisting of the nucleus medius hypothalamicus, the nucleus lateralis tuberis, and the nucleus lobi lateralis. some of the immunoreactive cells in the hypothalamus were identified as cerebrospinal fluid-contacting neurons. The bulk of the immunostained fibers in the nervus terminalis penetrated into the midventral portion of the telencephalon and ran dorsocaudally toward the basal telencephalon and hypothalamus, showing radial projections or ramifications. The labeled fibers were abundant in the midbasal part of the telencephalon and in the hypothalamus, where some fibers were found in loose networks around the cell bodies of the nucleus septi and hypothalamic periventricular nuclei. The fibers demonstrated in the hypothalamus terminated around the vascular wall of the primary capillary plexus of the median eminence or penetrated deeply into the pars intermedia of the hypophysis. These results suggest that, in the dogfish, an FMRFamide-like substance participates in the regulation of adenohypophysial function. This molecule may have a role as a neurotransmitter and/or neuromodulator in the central nervous system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00398072
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  • 84
    Digitale Medien
    Digitale Medien
    The developmental morphology ofIndotristicha ramosissima (Podostemaceae, Tristichoideae) (1991)
    Springer
    Plant systematics and evolution 178 (1991), S. 195-223 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Podostemaceae ; Tristichoideae ; Indotristicha ramosissima ; Rheophytes ; water plants ; life history ; development ; root-shoot model ; leaf-stem intermediates ; phyllotaxis ; flower structure ; systematics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The developmental morphology ofIndotristicha ramosissima, a submerged rheophyte from South India, is described. Besides creeping organs (called roots) there are branched shoots with two kinds of short-lived photosynthetic appendages: scales and compound structures (called ramuli). These ramuli may be interpreted as leaf-stem intermediates because they combine typical leaf characters (extra-axillary position, determinate growth, subtending an axillary bud) and typical stem characters (nearly radial symmetry, acropetal development with apical meristem, arrangement of the scaly subunits helical or irregular). Floral shoots arise from axillary exogenous buds along the vegetative shoots, occasionally also from endogenous buds along the roots and vegetative shoots. The uppermost scales and ramuli of each floral shoot form a cup-like structure around the base of the terminal flower.Indotristicha is thought to be primitive within theTristichoideae (Podostemaceae). Some morphogenetic switches are postulated in order to deriveIndotristicha from a putative ancestor that still showed the classical root-shoot model typical of most angiosperms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00937964
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  • 85
    Digitale Medien
    Digitale Medien
    Quantitative nuclear DNA changes inEleusine (Gramineae) (1991)
    Springer
    Plant systematics and evolution 178 (1991), S. 225-233 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Gramineae ; Eleusine ; DNA amount ; intra- and interspecific variation ; karyotypes ; hybridisation ; polyploidy ; domestication ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract 2C nuclear DNA amounts were determined in 30 collections belonging to 10 species ofEleusine. About a 2.5-fold variation in genome size is evident in the genus. The 2C DNA amount in the diploid species ranged from 2.50 pg inE. verticillata to 3.35 pg inE. intermedia. In contrast, the tetraploid species showed a range from 4.95 pg inE. africana to 6.13 pg inE. floccifolia. At intraspecific level 10 collections ofE. coracana, 6 ofE. indica, 4 ofE. africana, 2 ofE. tristachya, and 2 ofE. kigeziensis did not show any significant variation. However, 2 collections ofE. floccifolia, connected with polyploidy, displayed about 90% variation. Polyploid species showed approximately double the genome size of that of their corresponding diploids. An evolutionary increase in DNA amount is evident inE. coracana during the course of its origin and domestication fromE. africana.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00937965
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  • 86
    Digitale Medien
    Digitale Medien
    Polyploidy and aneuploidy inOphrys, Orchis, andAnacamptis (Orchidaceae) (1991)
    Springer
    Plant systematics and evolution 178 (1991), S. 235-245 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Orchidaceae ; Ophrys ; Orchis ; Anacamptis ; Polyploidy ; aneuploidy ; karyology ; systematics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Studies on chromosome numbers and karyotypes in Orchid taxa from Apulia (Italy) revealed triploid complements inOphrys tenthredinifera andOrchis italica. InO. tenthredinifera there is no significant difference between the diploid and the triploid karyotypes. The tetraploid cytotype ofAnacamptis pyramidalis forms 36 bivalents during metaphase I in embryo sac mother cells. Aneuploidy was noticed inOphrys bertolonii ×O. tarentina with chromosome numbers n = 19 and 2n = 38. There were diploid (2n = 2x = 36), tetraploid (2n = 4x = 72), hexaploid (2n = 6x = 108) and octoploid (2n = 8x = 144) cells in the ovary wall of the diploid hybridOphrys apulica ×O. bombyliflora. Evolutionary trends inOphrys andOrchis chromosomes are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00937966
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  • 87
    Digitale Medien
    Digitale Medien
    Pollination of four sympatric species ofAngelonia (Scrophulariaceae) by oil-collecting bees in NE. Brazil (1991)
    Springer
    Plant systematics and evolution 178 (1991), S. 153-178 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Scrophulariaceae ; Angelonia ; Anthophoridae ; Centris ; Oil flowers ; pollination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The manner whereby the oil-producing bisaccate flowers ofAngelonia (Scrophulariaceae) are pollinated by female oil-collecting bees is reported for the first time. Observations were made in the Caatinga formation of Pernambuco, NE. Brazil, on four synchronopatric species. These differ in sizes and structural details of the corolla, level of flower exposition, and habitat preferences. All legitimate visitors wereCentris spp. (Anthophoridae):Angelonia hirta was mainly pollinated byC. fuscata andA. pubescens byC. hyptidis; A. bisaccata andA. hookeriana shared an unidentified species. Several exomalopsine, tetrapediine and meliponid bees exploit the flowers less descriminately for oil or pollen, respectively, without regularly contacting anthers and stigma. The flowers are protandrous, and are self-incompatible except those of the annualA. pubescens. After alighting, theCentris bees introduce their front legs simultaneously into each of the pouches and start alternate collecting movements to gather the oil from the trichome elaiophores. While doing so, they are forced by projections of the corolla floor to press their head under the anthers and stigma, whereby pollen is transferred with their frons or clypeus. On account of their collector type and behaviour,C. fuscata andC. spec. are not specialized toAngelonia but may equally exploit other nonrelated taxa for oil, whereasC. hyptidis exhibits oligolecty onA. pubescens. It possesses relatively elongate forelegs with padlike collectors suitable for sweeping the lipids from the scattered glandular hairs inside the divergent spurs of its host. It is the only species that also collects pollen (by buzzing) from the oil host.A. hirta and relatives, provided with dense elaiophore carpets, are, for their part, adapted to “scraping”Centris species with typical oil collectors. Flower and bee phenologies, although largely dependent on the irregular rainfalls, are not always coincident.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00937962
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  • 88
    Digitale Medien
    Digitale Medien
    Androecium and floral nectaries ofHarungana madagascariensis (Clusiaceae) (1991)
    Springer
    Plant systematics and evolution 178 (1991), S. 179-194 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Clusiaceae ; Harungana madagascariensis ; Androecium ; stamenpetal complex ; floral nectaries ; floral development ; floral anatomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The mature flower ofHarungana madagascariensis (Choisy)Poir. has an androecium of five antipetalous fascicles, consisting of four stamens each. The stamen fascicles alternate with five indented nectary scales. A SEM-study of the floral development, as well as a study of the floral anatomy was carried out to understand whether the nectariferous scales represent staminodia or are receptacular in nature and consequently whether or not the androecium ofHarungana, and theClusiaceae in general, is originally diplostemonous. The five petals originate by the splitting of petal-stamen complexes. Next the upper part of each complex differentiates basipetally in four stamens. The stamens remain fascicled and are lifted on a long stalk at maturity. Five carpel primordia are initiated united in a low ringwall. The five nectary scales appear after carpel inception and develop an external morphology reminiscent of anthers. The floral anatomy reveals an independent origin of sepal median traces and common sepal lateral traces, free petal traces, stamen fascicle traces and alternating vascular tissue which supplies the nectaries. The petal-stamen complexes are the result of a retardation in petal inception, linked with the absorption of petal tissue into the stamen primordia. The development of the stamen fascicles is discussed; it is suggested that they are of a secondary nature and do not appear as a reduction from a multistaminate androecium. The external morphology and vascular anatomy of the scales speaks in favour of a staminodial nature. The comparison with some other species of theClusiaceae gives evidence of a diplostemonous ancestry of the androecium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00937963
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  • 89
    Digitale Medien
    Digitale Medien
    Effect of 1,10-phenanthroline on ultrastructure of pea leaves (1991)
    Springer
    Protoplasma 161 (1991), S. 23-30 
    Details
    ISSN: 1615-6102
    Schlagwort(e): 1,10-Phenanthroline ; Photodynamic herbicides ; Pisum sativum ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have examined ultrastructural changes of mesophyll cells in pea leaves induced by the photodynamic herbicide 1,10-phenanthroline (Phe). Dark incubation of pea plants did not cause any damage in plants or changes in the ultrastructure of mesophyll cells. Two hours of illumination after pretreatment with Phe caused photooxidative damage in plant but was not sufficient to markedly change the ultrastructure, although dilation of endoplasmic reticulum (ER) cisternae occurred. Illumination for 12 h caused inhibition of grana formation in pretreated plants. These ultrastructural changes and the inhibition of chlorophyll (Chl) accumulation may be due to the inhibition of transport of certain proteins to the plastids, diminished accumulation of chlorophyll proteins (e.g., LHCP) and a decrease in activity of the chlorophyll synthetase.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01328894
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  • 90
    Digitale Medien
    Digitale Medien
    Intercellular permeability inAbutilon nectary trichomes (1991)
    Springer
    Protoplasma 161 (1991), S. 150-159 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Abutilon ; Lucifer Yellow ; Microinjection ; Nectary ; Transport ; Trichome ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Intercellular transport was examined in nectary hairs ofAbutilon slriatum var.thompsonii using dye-uptake and microinjection followed by fluorescence and electron microscopy. Dye-uptake experiments demonstrated that both Lucifer Yellow CH (LYCH) and diaminobenzidine (DAB) move centrifugally along an apoplastic pathway from the sepellary tissue towards the tip cell. Further, fluorescence of LYCH could also be detected inside the cells of the nectary trichome. When LYCH or LYCH/DAB were microinjected into the tip cell, the dye spread in a centripetal direction towards the stalk cell. Electron microscopical investigations of microinjected nectary hairs revealed numerous electron-opaque globules in the cytoplasm of the nectary hair cells. In addition, multivesicular bodies, nuclei with opaque regions and changes in the rough endoplasmic reticulum (RER) were seen in nectary hair cells even at very low concentrations of injected dye. Ultrastructural investigations provided evidence for cytological changes in microinjected nectary hairs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01322727
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  • 91
    Digitale Medien
    Digitale Medien
    Ultrastructural immunolocalization of actin in a fungus (1991)
    Springer
    Protoplasma 163 (1991), S. 199-202 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Actin ; Freeze substitution ; Fungi ; Hyphal tip ; Immunocytochemistry ; Magnaporthe grisea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have successfully localized fungal actin for the first time using immuno-electron microscopy and hyphal tips of the rice blast pathogenMagnaporthe grisea. Following ultrarapid freezing, samples were processed in a novel substitution fluid of 10% acrolein in anhydrous ethanol and embedded in LR White resin. A monoclonal anti-actin antibody, previously shown to recognizeM. grisea actin, bound specifically to filasomes concentrated in the peripheral cytoplasm of subapical regions, and to the core-region of the Spitzenkörper.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01323344
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  • 92
    Digitale Medien
    Digitale Medien
    Immunocytochemical localization of nuclear antigens in the unicellular green alga,Chlamydomonas reinhardtii, processed by cryofixation and freeze-substitution (1991)
    Springer
    Protoplasma 165 (1991), S. 189-202 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Chlamydomonas ; Cryofixation ; Freeze-substitution ; Immunocytochemistry ; Nuclear proteins ; Nucleus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We describe the preparation of monoclonal antibodies to nuclear antigens in the green alga,Chlamydomonas reinhardtii, and their localization at the light and electron microscope level. Supernatants from hybridomas were screened by the ELISA method and the four antibodies giving the strongest signal were subjected to further analysis. At the LM level immunogold silver staining was used on semi-thick resinless sections. We have examined at the EM level the distribution of these antigens by post-embedding immunocytochemical techniques on sections of conventionally fixed specimens compared to cryofixed and freeze-substituted ones. Enhanced ultrastructural preservation was observed in cells which were cryofixed, freeze-substituted and embedded at −35°C in Lowicryl K4M. Different preparative procedures involving cryofixation and substitution are described. Of the four antibodies three were localized under light and electron microscopy. All three were distributed in the interchromatin space. One of these antigens (QUL4D2, 54 kDa) is also found in the dense fibrillar component and fibrillar centers of the nucleolus.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01322289
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  • 93
    Digitale Medien
    Digitale Medien
    Double fertilization inEphedra trifurca, a non-flowering seed plant: The relationship between fertilization events and the cell cycle (1991)
    Springer
    Protoplasma 165 (1991), S. 106-120 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Angiosperms ; Cell cycle ; Double fertilization ; Endosperm ; Ephedra
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Fertilization inEphedra trifurca was examined with a combination of light and fluorescence microscopy. Developmental analysis clearly indicates that double fertilization events, similar to those described inE. nevadensis, regularly occur during the process of sexual reproduction inE. trifurca. In addition to the typical fusion of a sperm nucleus and egg nucleus, a second fertilization event occurs between the second sperm nucleus from an individual pollen tube and the ventral canal nucleus. Both of the fertilization events take place within the confines of an individual egg cell of the female gametophyte. Microspectrofluorometric data demonstrate that each nucleus involved in a sexual fusion event proceeds through the synthesis phase of the cell cycle and increases its DNA content from 1C to 2C before the process of nuclear fusion is completed. Photometric data also confirm that the product of the second fertilization event is equal in DNA content (4C) to the zygotic nucleus derived from the first fertilization event, and is prepared to enter into mitosis as a fully functional diploid nucleus.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01322281
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  • 94
    Digitale Medien
    Digitale Medien
    Ultrastructure of the vegetative organisation and initial stages of silica plate deposition in the soil testate amoebaCorythion dubium (1991)
    Springer
    Protoplasma 163 (1991), S. 136-144 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Corythion dubium ; Silica deposition ; Testate amoeba ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The siliceous body plates ofCorythion dubium are bound by a band of organic cement which is thickest at the lateral margins. The anterior vacuolar cytoplasm is separated by a pigment zone, which forms a dark band in the mid-body region, from the compact posterior region containing a typical vesicular nucleus surrounded by a region of dense endoplasmic reticulum. A pellicular basket of microtubules surrounds the posterior cytoplasm. The large Golgi complex lies between the nucleus and the fundus. Numerous coated and uncoated vesicles from the Golgi cisternae are seen in the peripheral cytoplasm alongside developing plates. These small siliceous plates are enclosed in silicon deposition vesicles lying in surface ruffles of the plasmalemma, often in association with a pair of microtubules. Observations are made on the formation of these vesicles and the early stages of silica deposition. A comparison is drawn between silica deposition inC. dubium and choanoflagellates where there is a similar association between silicon deposition vesicles and microtubules.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01323337
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  • 95
    Digitale Medien
    Digitale Medien
    Localization and characterization of pectic polysaccharides in roots and root nodules ofCeanothus spp. during intercellular infection byFrankia (1991)
    Springer
    Protoplasma 163 (1991), S. 93-101 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Polygalacturonan ; Pectin ; Methyl esterification ; Extracellular matrix ; Frankia ; Ceanothus ; Root nodule ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary During early stages of nodule development inCeanothus spp., theFrankia infection pathway is characterized by a distinctive host-derived extracellular matrix. In the present study, a major component of the host interface is shown to consist of pectic polysaccharides. The distribution of these pectic polysaccharides in developing nodules has been delineated in root and nodule tissue. The levels of polygalacturonic acid detected were extremely high in the root mucilage and in the intercellular infection matrix in the root cortex, as detected by indirect immunogold localization with an antibody, and with fluorescein-conjugated alginate and pectate probes. Polygalacturonans in the intercellular matrix and in nodule tissue were predominantly esterified. The non-esterified polygalacturonans were located in cell junctions. Within the infected nodule cortical cells, (poly)galacturonate content of the interfacial encapsulation surrounding theFrankia endosymbiont was very high, while the cell walls were not labeled above background, suggesting that the encapsulation is a specialized wall layer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01323333
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  • 96
    Digitale Medien
    Digitale Medien
    Effects of heat shock and thermoadaptation on the ultrastructure of cowpea (Vigna unguiculata) cells (1991)
    Springer
    Protoplasma 163 (1991), S. 125-135 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Cowpea ; Heat shock ; Thermoadaptation ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Suspension culture cells of cowpea (Vigna unguiculata) were examined using transmission electron microscopy to characterize morphological changes associated with hyperthermal stress. Cultures maintained at 26°C (unadapted cells) and 38°C (thermoadapted cells) were examined before and after exposure to elevated temperatures of 34°C and 45°C, respectively. Observations indicate that while there were significant ultrastructural differences between unadapted and thermoadapted cells, the following structural modifications in response to heat stress were observed in cells of both cultures: (a) almost a complete loss of polyribosomes, rough ER, and dictyosomes, (b) migration of intracellular waste material (presumably proteinaceous in composition) into the cell vacuole, (c) swelling of the nucleolus with assumed accumulation of preribosomal RNP granules, and (d) retraction of the tonoplast from the cytoplasm into the vacuoles of some cells. Heat shock granules (two size classes) were observed in the cytoplasm of stressed thermoadapted cells along with hollow-cored granules within the leucoplasts. Apart from a few minor differences, the morphological modifications that were made in apparent response to hyperthermal stress were remarkably similar in both cultures.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01323336
    Standort Signatur Erwartet Verfügbarkeit
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  • 97
    Digitale Medien
    Digitale Medien
    Ontogeny and ultrastructure of spontaneous nodules in alfalfa (Medicago sativa) (1991)
    Springer
    Protoplasma 162 (1991), S. 1-11 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Rhizobium meliloti ; Development ; Symbiosis ; Nitrogen fixation ; Ultrastructure ; Spontaneous nodule
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The development of spontaneous nodules, formed in the absence ofRhizobium and combined nitrogen, on alfalfa (Medicago sativa L. cv. Vernal) was investigated at the light and electron microscopic level and compared to that ofRhizobium-induced normal nodules. Spontaneous nodules were initiated from cortical cell divisions in the inner cortex next to the endodermis, i.e., the site of normal nodule development. These nodules, on uninoculated roots, were white multilobed structures, histologically composed of nodule meristems, cortex, endodermis, central zone and vascular strands. Nodules were devoid of intercellular or intracellular bacteria confirming microbiological tests. Early development of spontaneous nodules was initiated by series of anticlinal followed by periclinal divisions of dedifferentiated cells in the inner cortex of the root. These cells formed the nodular meristem from which the nodule developed. The cells in the nodule meristems divided unequally and differentiated into two distinct cell types, one larger type being filled with numerous membrane-bound starch grains, and the other smaller type with very few starch grains. There were no infection threads or bacteria in the spontaneous nodules at any stage of development. This size differentiation is suggestive of the different cell sizes seen inRhizobium-induced nodules, where the larger cell type harbours the invading bacteria and the smaller type is essential in supportive metabolic roles. The ontogenic studies further support the claim that these structures are nodules rather than aberrant lateral roots, and that plant possess all the genetic information needed to develop a nodule with distinct cell types. Our results suggest that bacteria and therefore theirnod genes are not necessarily involved in the ontogeny and morphogenesis of spontaneous and normal nodules in alfalfa.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01403895
    Standort Signatur Erwartet Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    RuBisCo activase is present in the pyrenoid of green algae (1991)
    Springer
    Protoplasma 162 (1991), S. 38-45 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Green algae ; Immunocytochemistry ; Pyrenoid ; RuBisCo ; RuBisCo activase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary RuBisCo activase catalyzes the activation and maintains the activated state of the photosynthetic enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCo, EC 4.1.1.39). We employed antisera prepared against the RuBisCo holoenzyme purified from tobacco and RuBisCo activase isolated from spinach to determine the localization of these proteins in leaves of C3-type higher plants and green algae. In leaves ofVicia faba, both RuBisCo activase and RuBisCo are distributed throughout the chloroplast stroma. In contrast, RuBisCo activase and RuBisCo are predominantly localized to the pyrenoid in the green algaeChlamydomonas reinhardtii andColeochaete scutata. The co-immunolocalization of RuBisCo activase and RuBisCo to the pyrenoid in these two green algal species suggests that pyrenoid-localized RuBisCo is catalytically competent. We conclude that the pyrenoid functions as a unique metabolic compartment of the chloroplast in which the reactions of the photosynthetic carbon reduction pathway are initiated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01403899
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
    Digitale Medien
    Digitale Medien
    Distribution of naturally occurring quinones (1991)
    Springer
    Pharmacy world & science 13 (1991), S. 70-73 
    Details
    ISSN: 1573-739X
    Schlagwort(e): Algae ; Angiosperms ; Arthropods ; Bacteria ; Fungi ; Lichens ; Marine animals ; Quinones, naturally occurring
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Angiosperms, fungi (including lichens), and bacteria are the main sources of natural quinones. Small numbers are present in algae, ferns, conifers, sponges, echinoderms, other marine animals, and arthropods. In angiosperms quinones have some chemotaxonomic value at the genus and family level but more surveys are required.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01974983
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    Experimental documentation of natural hybridization inCactaceae: Origin of Lloyd's Hedgehog Cactus,Echinocereus ×lloydii (1991)
    Springer
    Plant systematics and evolution 178 (1991), S. 107-122 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Cactaceae ; Echinocereus ; Natural hybridization ; systematics ; dioecy ; flavonoids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The origin ofEchinocereus ×lloydii Britt. & Rose, pro sp. (Lloyd's Hedgehog Cactus) was investigated using comparative morphology, cytology, biochemistry, and particularly, artificial hybridization. Numerous artificial crosses between the putative parentsE. coccineus Engelm. (a species of claret-up cactus) andE. dasyacanthus Engelm. (Texas Rainbow Cactus) were successful, resulting in the production of hundreds of seeds with hybrid embryos. The F1 hybrid progeny (i.e., syntheticE. ×lloydii) grew to sexual maturity in about four and one-half years, whereupon successful backcrosses and F2 generation hybrids were also obtained. The known F1 hybrids closely approximated naturalE. ×lloydii. The fertility of these syntheticE. ×lloydii was high, like their natural counterparts. The populations ofE. ×lloydii in Pecos County, Texas are inferred to have originated as the result of natural interspecific hybridization. It is assumed thatE. ×lloydii or similar plants may arise wherever the parental taxa grow sympatrically.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00937985
    Standort Signatur Erwartet Verfügbarkeit
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