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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 90 (1999), S. 257-266 
    ISSN: 1570-7458
    Schlagwort(e): host suitability ; acceptance ; biological control ; new associations ; Lepidoptera ; Pyralidae ; New World ; Old World ; stemborers ; Braconidae ; larval parasitoids ; Gramineae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The present study examined the acceptability and suitability of Old World stemborers (Chilo partellus and C. orichalcociliellus) for the development of New World parasitoids (Apanteles deplanatus and A. minator) and New World stemborers (Diatraea saccharalis and D. grandiosella) for the development of Old World parasitoids (Cotesia sesamiae, C. flavipes and C. chilonis). Results revealed that acceptance and suitability were high in old associations. In new associations, parasitoids accepted about 60% of the new association hosts. In addition, 10 out of 17 new associations were successful. Apanteles species appeared to be more physiologically host specific than Cotesia species. For example, two of four new association hosts were accepted by A. deplanatus and only one (D. saccharalis) was partially suitable for progeny development. Among the Cotesia species, Cotesia flavipes appeared to have a wider host range than the two other species. It attacked all hosts offered and successfully parasitized all but one (D. grandiosella). Diatraea saccharalis was accepted and was a suitable host for the development of all parasitoid species tested, whereas D. grandiosella was unsuitable for the development of four out of five parasitoid species tested. No clear pattern was observed as behavioral acceptance did not always agree with the pattern of physiological suitability. Implications of these findings for importation biological control of stemborers are discussed.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 91 (1999), S. 327-336 
    ISSN: 1570-7458
    Schlagwort(e): biological control ; in vitro rearing ; rearing techniques ; host selection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract An artificial host egg was developed as a first attempt to improve the techniques for in vitro rearing of Trichogramma galloi Zucchi and T. pretiosum Riley (Hymenoptera, Trichogrammatidae). Plastic membranes (polyethylene, polypropylene and polystyrene) of different thickness were tested for their usefulness in manufacturing artificial eggs, using a thermal system to produce semi-spherical cupules on the plastic surface. These artificial eggs were filled with larval hemolymph of Helicoverpa zea (Boddie) (Lepidoptera, Noctuidae), and the optimal size of the artificial egg and density of females/artificial egg for the highest host acceptance (percentage of artificial eggs with at least one parasitoid egg) as well as the ideal level of parasitism (eggs/artificial egg) were determined. High-density polyethylene 7–8 and 9–10 μm thick resulted in the best acceptance and level of parasitization for both parasitoid species. Six females per artificial egg resulted in the best rate of parasitization for these parasitoids, although these data were not different when using 4 or 5 females of T. galloi. The size, shape and surface texture of the artificial eggs were found to provide enough cues to elicit parasitization behavior in Trichogramma females, since no chemical stimulus was provided.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    ISSN: 1570-7458
    Schlagwort(e): Trichogramma spp. ; Helicoverpa armigera ; Chrysoperla carnea ; Portugal ; parasitism ; biological control ; non-target species
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Parasitism of two host species by five Trichogramma species (Hymenoptera, Trichogrammatidae) was studied in the laboratory. The host species were: i) the bollworm Helicoverpa armigera Hübner (Lepidoptera, Noctuidae), an important pest of many crops in the tropics and subtropics, and ii) one of its natural enemies, the lacewing Chrysoperla carnea Stephens (Neuroptera, Chrysopidae), a predator often used as a biological control agent. The proportion of H. armigera eggs parasitized from the total number of parasitized hosts differed between Trichogramma species. The average number of parasitized eggs per female in 24 h by Trichogramma pintoi and T. bourarachae was 10 of H. armigera and about 0.5 of C. carnea. For the other three Trichogramma species (T. cordubensis, T. evanescens and T. turkestanica) these averages varied from 6 to 11 H. armigera eggs and from 3 to 4 C. carnea eggs. Total adult offspring production, contacts with hosts, secondary clutch size and sex-ratio of each Trichogramma species were determined as well. The results show that sympatric Trichogramma may parasitize target and non-target species in different proportions. If this difference corresponds to the field situation, simple laboratory tests could be performed to select not only efficient biogical control agents, but also species which are the least detrimental to non-target hosts.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 92 (1999), S. 21-28 
    ISSN: 1570-7458
    Schlagwort(e): host feeding ; host paralysis ; oviposition ; pre-oviposition phase ; Hypothenemus hampei ; Scolytidae ; biological control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effect of the density of the coffee berry borer, Hypothenemus hampei (Coleoptera: Scolytidae) on reproductive and host-feeding behaviours of the parasitoid Cephalonomia stephanoderis (Hymenoptera: Bethylidae) was evaluated under laboratory conditions. The number of hosts used for oviposition was density-dependent at low host density. Beyond a density of six hosts/day, the oviposition rate reached a maximum of 1.2 eggs/day due to egg limitation. Cephalonomia stephanoderis females responded to increasing host availability with a linear increase in host feeding. Overall, parasitoids killed more coffee berry borers by feeding and paralysis than by parasitism. At low host density, the pre-oviposition phase was extended, oogenesis was delayed, more males were produced, and host feeding occasionally occurred concurrently with oviposition. We suggest that the efficacy of C. stephanoderis as a biological control agent depends on seasonal variations in host density. Inoculative vs inundative releases in coffee plantations are discussed in relation to the abundance of the coffee berry borer during the fructification and interharvest periods.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 91 (1999), S. 449-457 
    ISSN: 1570-7458
    Schlagwort(e): Schizaphis graminum ; Aphelinus asychis ; aphid ; parasitoid ; natural enemy ; biological control ; greenbug ; host selection ; plant volatile
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Aphelinus asychis (Walker) can be valuable as a biocontrol agent of the aphid, Schizaphis graminum (Rondani), a major pest on grain crops in the United States. This study reports the wind tunnel, and olfactometric responses of this parasitoid to the host (aphid), plant (sorghum), and host-plant complex (aphid-infested sorghum). In addition, the parasitoids' response to malathion-treated plants is also presented. The goal of the present study was to test the hypothesis that volatiles associated with the host attract natural enemies, as reported in cases of many hymenopterous parasitoids, and also to learn about the effects of insecticides on these parasitoids. In wind tunnel studies, these parasitoids moved upwind in the direction of the host-infested plant. There was no direct flight observed, however, these parasitoids were observed to hop and jump, and sometimes walk to their host. In the olfactometer experiments, we found that A. asychis is attracted to host-plant complex. The parasitoids' response to malathion in the olfactometer suggested that a malathion formulation when applied to plants can lure these beneficials, thus providing new insight into the ongoing task of integrating chemical and biological control of insect pests.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 93 (1999), S. 267-273 
    ISSN: 1570-7458
    Schlagwort(e): Macrolophus caliginosus ; mirid bug ; life table ; longevity ; fecundity ; development time ; mortality ; sex ratio ; oviposition period ; intrinsic rate of increase ; spider mite ; Tetranychus urticae ; tomato ; biological control ; glasshouse pests
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The life table characteristics of the polyphagous mirid Macrolophus caliginosus Wagner (Heteroptera: Miridae) preying on various stages of Tetranychus urticae Koch (Acari: Tetranychidae) with tomato as host plant were described at 22 °C. The following average parameters were obtained: Female longevity: 28.7 days; fecundity: 0.7 eggs/female/day; egg mortality: 2.6%; pre-oviposition period: 5.5 days; oviposition period: 18.1 days; post-oviposition period: 3.2 days; juvenile development time: 26.8 days; juvenile mortality: 34.9%; and sex ratio (♀/(♀+♂): 0.46. Life table parameters were estimated as net reproduction rate (R 0): 6.15; intrinsic rate of increase (r m): 0.031 day−1; finite rate of increase (λ): 1.032; mean generation time (T c): 58.17 days; and doubling time (T 2) 22.2 days. The parameters obtained were in accordance with those reported for M. caliginosus fed on another mite species (T. turkestani Ugarov & Nikolski (Acari: Tetranychidae)). However, compared to the performance of M. caliginosus fed on common glasshouse insect pests, a diet consisting of only mites appeared to be inferior. However, being a voracious predator, M. caliginosus may be a valuable addition to existing methods of mite control.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 92 (1999), S. 73-82 
    ISSN: 1570-7458
    Schlagwort(e): biological control ; food web interactions ; volatiles ; Phytoseiidae ; predatory bugs ; thrips ; predator-predator interactions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Arthropods use odours associated with the presence of their food, enemies and competitors when searching for patches. Responses to these odours therefore determine the spatial distribution of animals, and are decisive for the occurrence and strength of interactions among species. Therefore, a logical first step in studying food web interactions is the analysis of behaviour of individuals that are searching for patches of food. We followed this approach when studying interactions in an artificial food web occurring on greenhouse cucumber in the Netherlands. In an earlier paper we found that one of the predators of the food web, the predatory mite Phytoseiulus persimilis Athias-Henriot, used to control spider mites, discriminates between odours from plants with spider mites, Tetranychus urticae Koch, and plants with spider mites plus conspecific predators. The odours used for discrimination are produced by adult prey in response to the presence of predators, and probably serve as an alarm pheromone to warn related spider mites. Other predator species may also trigger production of this alarm pheromone, which P. persimilis could use in turn to avoid plants with heterospecific predators. We therefore studied the response of the latter to odours from plants with spider mites and 3 other predator species, i.e. the generalist predatory bug Orius laevigatus (Fieber), the polyphagous thrips Frankliniella occidentalis and the spider-mite predator Neoseiulus californicus (McGregor). Both olfactometer and greenhouse release experiments yielded no evidence that P. persimilis avoids plants with any of the 3 heterospecific predators. This suggests that these predators do not elicit production of alarm pheromones in spider mites, and we argue that this is caused by a lack of coevolutionary history. The consequences of the lack of avoidance of heterospecific predators for interactions in food webs and biological control are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 93 (1999), S. 51-61 
    ISSN: 1570-7458
    Schlagwort(e): Metarhizium anisopliae ; Atta sexdens rubropilosa ; leaf-cutting ants ; biological control ; social homeostasis ; entomopathogenic fungus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract There is growing interest in the use of entomopathogenic organisms to control leaf-cutting ants (Hymenoptera: Formicidae: Attini). However, the way leaf-cutting ants react as a colony to biohazards is poorly understood. We investigated the effects of Metarhizium anisopliae (Metschnikoff) (Deuteromycotina: Hyphomycetes) applied to the foraging arenas of mini-nests (queenless sub-colonies) of the leaf-cutting ant Atta sexdens rubropilosa (Forel). Dry spores were applied either alone or mixed with citrus powder, at 0.5 g or 0.05 g per mini-nest. The spores were removed four days after application, and all dead ants removed every three days. Ant numbers near the Metarhizium increased as the ants attempted to clean up the biohazard. The ants attempted to place the spores in piles, which they then covered over with other material. They were able to deal with the low doses in this way, but the high doses overwhelmed them. All treated mini-nests suffered increased ant mortality during the first ten days after application. This mortality was particularly high in the media worker caste which had played the major role in attempting to clean up the spores. Foraging activity decreased, as did the health of the fungus gardens. The mini-nests exposed to the low dose of spores mixed with citrus powder then recovered fully. The health of the other treated mini-nests declined gradually until around 26 days after application, when they began deteriorating sharply. However, the decline of these mini-nests after day 26 was not due directly to the pathogenic action of the Metarhizium, nor to the initial ant mortality it had caused. The results suggest that the social stress caused by even such a short-lived Metarhizium epizootic was sufficient to cause the decline and ultimate death of the mini-nests. This has important implications for the control of leaf-cutting ants. It also demonstrates how important the social homeostasis of the colony is to leaf-cutting ants.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 93 (1999), S. 227-230 
    ISSN: 1570-7458
    Schlagwort(e): Rhopalosiphum padi ; cereal aphids ; wheat ; induced responses ; feeding site
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 90 (1999), S. 103-107 
    ISSN: 1570-7458
    Schlagwort(e): learning ; Orius majusculus (Reuter) ; Heteroptera ; Anthocoridae ; predator ; biological control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 90 (1999), S. 183-189 
    ISSN: 1570-7458
    Schlagwort(e): Hymenoptera ; Aphelinidae ; Platygasteridae ; Hemiptera ; Aleyrodidae ; whiteflies ; Bemisia ; Amitus bennetti ; parasitoid ; biological control ; life history ; instar preference ; oviposition behaviour
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Amitus bennetti Viggiani & Evans (Hymenoptera: Platygasteridae) is a recently described parasitoid of the silverleaf whitefly, Bemisia argentifolii Bellows & Perring (Homoptera: Aleyrodidae). Behaviour and life history of the parasitoid are described. The first nymphal instar of B. argentifolii is preferred by the parasitoid, but the 1st through 4th instar may be parasitised. Females first investigate hosts with their antennae, then walk over the host, and eventually step with their front legs on the leaf and insert their ovipositor inside the host facing away from the host, while the hind legs are still on the host. The time from encounter to oviposition (=latency to oviposition) is shortest on the 1st instar. Oviposition duration (mean=39 s) comprises 50% of the handling time. Development time from egg to adult decreases from 72 days at 15 °C to 42 days at 20 °C to 28 days at 25 °C. We estimate that 400 degree days is required for development, with a development threshold of 10 °C. Adult longevity in the absence of hosts was 29, 26 and 19 days and with hosts present 8, 8 and 5 days at 15, 20 and 25 °C, respectively. Amitus bennetti is proovigenic and oviposits most eggs shortly after adult emergence. During the first day of their adult lives females laid 1, 31 and 49 eggs at 15, 20 and 25 °C, respectively. Compared with other parasitoid species, the development time of A. bennetti is very long, and the implications of this for management of B. argentifolii are discussed.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 92 (1999), S. 157-164 
    ISSN: 1570-7458
    Schlagwort(e): plant resistance ; antibiosis ; tolerance ; antixenosis ; Russian wheat aphid ; wheat ; Homoptera ; Aphididae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The Russian wheat aphid, Diuraphis noxia (Mordvilko), is one of the most important aphid pests of wheat, Triticum aestivum L., worldwide. Among the various pest management options, plant resistance is an economical management tactic to control D. noxia in cereal crops such as wheat. Researchers have identified D. noxia resistant germplasm and it has been incorporated into wheat. This study compared D. noxia resistance between the ‘Betta’ wheat isolines Betta-Dn1, Betta-Dn2, and Betta-Dn5 and their corresponding donor gene plant introduction (PI) lines PI 137739 (Dn1), PI 262660 (Dn2), and PI 294994 (Dn5). Although the Betta isolines and PI lines showed D. noxia resistance when compared with Betta wheat, the degree of resistance in the isolines to D. noxia was different from their corresponding PI donors. Aphid number, aphid fecundity, and biomass per aphid were not different between Betta-Dn1 and PI 137739 or Betta-Dn2 and PI 262660; however, the same parameters were significantly lower on PI 294994 compared with Betta-Dn5. This indicated that aphid resistance in PI 137739 and PI 262660 was probably governed by a single dominant gene, while the resistance in PI 294994 was controlled by more than one gene. Additionally, plant biomass reduction was aphid density dependent, which suggested that use of appropriate aphid infestation level is important when using plant biomass reduction as an indicator of resistance. Plant resistance categorization showed that there was no detectable difference in antixenosis among the seven lines evaluated. However, the higher aphid fecundity observed on PI 262660 compared with PI 137739 and PI 294994, in addition to no significant differences among the three PIs in plant biomass reduction, suggested PI 262660 was a tolerant line, while PI 137739 and PI 294994 were antibiotic lines. Plant tolerance could not be elucidated among the three Betta isolines using aphid fecundity and plant biomass reduction as indicators.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 93 (1999), S. 77-86 
    ISSN: 1570-7458
    Schlagwort(e): Acari ; behaviour ; biological control ; Gerbera jamesonii ; herbivore induced synomones ; infochemicals ; indirect defence ; Phytoseiidae ; semiochemicals ; terpenoids ; Tetranychus urticae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Jasmonic acid (JA) is a plant hormone that is involved in the induction of plant defence in response to herbivore attack. We studied the effect of exposure of gerbera leaves to JA on indirect plant defence, i.e. attraction of natural enemies of herbivores. Treatment of gerbera leaves with JA or feeding damage by the herbivorous spider mite Tetranychus urticae, both induced the production of a complex odour blend that attracts the predatory mite Phytoseiulus persimilis. This phytoseiid predator is a very effective biological control agent of the spider mite T. urticae. Comparison of headspace composition of gerbera leaves exposed to either JA or T. urticae revealed a large degree of resemblance, but some quantitative and qualitative differences were recorded. The major chemical group in both treatments is formed by the terpenoids which quantitatively comprised up to 80% of the total odour blend. These terpenoids included (E)-4,8-dimethyl-1,3,7-nonatriene, (E)-β-ocimene and linalool that are known to attract P. persimilis. Aldehydes, alcohols, esters and ketones, together with nitrogenous compounds formed the remaining constituents of the odour blend. The induction of predator attractants in plants by JA may be applied in biological control programs, which is discussed in this paper.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 91 (1999), S. 111-114 
    ISSN: 1570-7458
    Schlagwort(e): sieve element ; salivation ; aphid ; plant resistance ; wheat ; Sitobion fragariae ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Extended sieve element salivation (E1 waveform in the electrical penetration graph) is a characteristic activity during early sieve element punctures, particularly in resistant plants. In order to explore a chemically-mediated mechanism of resistance associated with sieve element salivation, we compared the pattern of feeding behaviour of the aphid, Sitobion fragariae (Walker), on two cultivars of the wheat Triticum aestivum L., with different concentrations of hydroxamic acids (Hx). During 24 h of electronic monitoring, aphids dedicated over 50% of the total time to phloem ingestion from the sieve elements. Total time allocated to E1 in the experiment, time to first E1 within the experiment, time allocated to E1 before a sustained phloem ingestion (E2) and the contribution of sieve element salivation to the phloem phase (E1/[E1+E2]) were significantly higher in the high-Hx cultivar. The increased salivation in plants with higher contents of Hx suggests the existence, at least in this system, of a chemically-mediated sieve element constraint.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Journal of heuristics 5 (1999), S. 145-158 
    ISSN: 1572-9397
    Schlagwort(e): evolutionary algorithms ; genetic algorithms ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract This paper shows how evolutionary algorithms can be described in a concise, yet comprehensive and accurate way. A classification scheme is introduced and presented in a tabular form called TEA (Table of Evolutionary Algorithms). It distinguishes between different classes of evolutionary algorithms (e.g., genetic algorithms, ant systems) by enumerating the fundamental ingredients of each of these algorithms. At the end, possible uses of the TEA are illustrated on classical evolutionary algorithms.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 41 (1985), S. 265-266 
    ISSN: 1420-9071
    Schlagwort(e): Rat ; hydrochlorothiazide ; pain threshold ; antinociceptive activity ; analgesic activity ; morphine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Hydrochlorothiazide, acutely injected in rats, has a weak analgesic activity per se and potentiates and prolongs the antinociceptive effect of morphine.
    Materialart: Digitale Medien
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  • 17
    ISSN: 1420-9071
    Schlagwort(e): Hydroxamic acid ; cereals ; maize ; wheat ; aphids ; greenbug
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary 2-β-Glucosyl-4-hydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA-Glc), the main hydroxamic acid from maize and wheat, and its aglucone, decreased survival ofSchizaphis graminum reared on artificial diets. Both compounds were toxic for aphids and acted as feeding deterrents, at concentrations as low as 1 mM. The natural concentrations of glucosides of hydroxamic acids in wheat leaves reach up to 6 mmoles/kg fresh weight, thus falling within the range in which DIMBOA-Glc causes delecterious effects to diet-fed aphids.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 38 (1985), S. 171-175 
    ISSN: 1570-7458
    Schlagwort(e): biological control ; release ; establishment ; Hymenoptera ; Encyrtidae ; Epidinocarsis lopezi ; Cassava mealybug ; Homoptera ; Pseudococcidae ; Phenacoccus manihoti
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Epidinocarsis lopezi (Apoanagyrus) lopezi a été introduit du Paraguay au Nigéria pour lutter contre la cochenille du manioc, Phenacoccus manihoti. Il a été lâché dans quatre champs de manioc pour étudier son acclimatation et son installation au Nigéria. Trois ans après les lâchers, les résultats ont permis de conclure que E. lopezi s'est établi avec succès et se disperse dans la plupart des zones de culture du manioc au Nigeria; il a aussi survécu à trois saisons pluvieuses pendant lesquelles les populations de P. manihoti ont été très faibles. Quatorze mois après les premiers lâchers, cet encyrtide a été obtenu à environ 150 km du lieu de libération.
    Notizen: Abstract The encyrtid wasp Epidinocarsis (= Apoanagyrus) lopezi (De Santis) was imported from Paraguay into Nigeria for the biological control of the cassava mealybug, Phenacoccus manihoti Matile-Ferrero. It was mass-reared and released at four localities in Nigeria. The parasitoid is now established and it is dispersing throughout cassava growing areas of Nigeria.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 38 (1985), S. 3-13 
    ISSN: 1570-7458
    Schlagwort(e): Hymenoptera ; Trichogramma ; strains and species ; variations ; biological control ; candidate selection ; activity ; low temperature ; inundative releases
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Afin de sélectionner une souche de Trichogramma sp. (Hymenoptera, Trichogrammatidae) candidate pour des lâchés inondatifs contre les Lépidoptères pestes de chou aux Pays-Bas, l'activité de parasitisation d'une collection de 60 souches différentes de Trichogramma spp. a été étudiée à 12°C pendant des durées d'exposition de 2 h et 24 h. L'activité proportionnelle et le degré de parasitisation des femelles varient significativement selon des souches et ne sont par corrélés. Ceci suggère l'action des deux mécanismes distincts, dépendant de la température et contrôlant independamment chacun de ces processus. Les souches indigènes sont caractérisées par une faible activité à 12°C, mettant en doute leur utilisation pour les lâchés inondatifs. Dans 3 souches testées à 12, 17, 20, 25 et 30°C, l'activité augmente linéairement avec la température, jusqu'a ce que quasi toutes les femelles parasitent les oeufs hôtes à 20°C et 25°C. Le taux de parasitisation augmente avec la température atteignant un maximum à 20–25°C puis diminue à 30°C. Le temps de manipulation d'un oeuf hôte diminue asymptotiquement lorsque la température croît. Les résultats de cette étude suggèrent que la capacité d'adaptation aux températures basses varie selon les souches de Trichogramma. Cette caractéristique constitue un critère utile pour l'évaluation de souches candidates potentielles.
    Notizen: Abstract In order to select a candidate strain of Trichogramma sp. for inundative releases against lepidopteran pests in cabbage field-crops in the Netherlands, the parasitization activity of a collection of 60 different Trichogramma spp. strains was studied during 2 h and 24 h exposures at 12°C. Activity and parasitism varied significantly among strains and the two characteristics were not correlated, suggesting the action of two differentially temperature-dependent mechanisms influencing both characteristics. Native strains were characterized by a low activity at 12°C, making their usefulness for inundative releases doubtful. In three strains tested at 12, 17, 20, 25 and 30°C, activity increased linearly with temperature, until nearly all females parasitized at 20 or 25°C. Parasitism increased with increasing temperature to a maximum at 20–25°C and declined at 30°C. Handling time decreased asymptotically with increasing temperature. The results of this study suggest that Trichogramma strains vary in adaptability to low temperature, making this characteristic a useful criterion for evaluation of candidate strains.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 39 (1985), S. 177-182 
    ISSN: 1570-7458
    Schlagwort(e): biological control ; brassica ; labiate herbs ; larval feeding ; oviposition ; Lepidoptera ; Pieris brassicae ; Plutella xylostella
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Des plantes médicinales ont traditionnellement été utilisées en association avec des plantes cultivées dans l'espoir que leur odeur repousserait les insectes nuisibles. Des extraits à l'alcool et des essences volatiles de labiées médicinales ont été essayés au laboratoire pour examiner leur effets répulsif et dissuadant pour la ponte de Plutella xylostella et l'alimentation des chenilles de P. xylostella et Pieris brassicae. Les extraits alcooliques d'hysope, de romarin, de sauge, de thym et de trèfle blanc réduisent la ponte de P. xylostella sur des morceaux de feuilles de chou traitées. Les essences volatiles de sauge et de thym réduisent la ponte de P. xylostella sur des morceaux de feuilles de chou dans des expériences de choix. L'alimentation des chenilles de dernier stade de P. xylostella et P. brassicae dans des expériences de choix est réduite par l'application d'extraits alcooliques des labiées médicinales.
    Notizen: Abstract Herbs have been traditionally used as intercrops with crop plants on the assumption that their odour repels pest species. Alcohol extracts and essential oils of labiate herbs were tested in the laboratory for deterrent/repellent responses to ovipositing Plutella xylostella (L.) and feeding larvae of P. xylostella and Pieris brassicae L. Alcohol extracts of hyssop, rosemary, sage, thyme and white clover reduce oviposition by P. xylostella on pieces of brassica leaf in dual-choice tests. Essential oils of sage and thyme reduce oviposition on pieces of brassica leaf. Feeding, in dual-choice tests, by final instar P. xylostella and P. brassicae larvae is reduced by application of alcohol extracts of herbs.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 38 (1985), S. 113-120 
    ISSN: 1570-7458
    Schlagwort(e): diapause ; genetic improvement ; Metaseiulus occidentalis ; Tetranychus urticae ; Phytoseiidae ; Tetranychidae ; Acari ; glasshouse ; biological control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Au cours d'un programme destiné à évaluer la valeur du prédateur, Metaseiulus occidentalis Nesbitt pour lutter contre Tetranychus urticae Koch sur roses dans les serres de Berkeley (California) nous avons comparé chez deux souches le comportement lié à la diapause. Une souche a une diapause normale, l'autre a été sélectionnée génétiquement pour son absence de diapause. Les adultes avec diapause normale recherchent des abris sur un dispositif expérimental conçu à partir d'un pied de haricot. Les femelles perdant l'aptitude à la diapause ainsique celles de la souche normale soumise à une longue photophase ont tendance à se disperser par voie aérienne à partir du dispositif expérimental, surtout quand les proies sont rares. Les femelles de M. occidentalis aptes à la diapause élevées aux environs de la photophase critique (11.2h) avec des températures variant entre 17°5 et 24°5 pendant le nyctémère réagissent en fonction de la disponibilité en proies: quand les proies manquent, les prédateurs ont plus tendance à entrer en diapause que quand les proies sont abondantes. Avec une longue photopériode, les femelles à jeûn abandonnent le système expérimental, (probablement par dispersion aérienne) et les femelles fécondées se dispersent plus facilement que les mâles et les femelles vierges. Aucune différence dans la tendance à la dispersion aérienne n'a été observée aux courtes photophases. La dispersion aérienne des femelles adultes s'est produite à des vitesses de 1.5 m/sec.
    Notizen: Abstract Diapause behaviou of two strains of Metaseiulus occidentalis (Nesbitt) was compared as part of a project to evaluate this predator as a control agent for Tetranychus urticae Koch on roses in greenhouses in Berkeley, California. One strain had a normal diapause and the other had been genetically selected for ‘non-diapause.’ Predators in diapause sought shelters on a simple bean plant test system. Females lacking the ability to diapause and the normal strain under long photophases tended to disperse aerially from the bean plant systems, particularly when prey were scarce. M. occidentalis females with the capacity to diapause reared near the critical photophase (11.2h) at fluctuating temperatures of 17.5 to 24.5°C within a 24 h period were influenced by the availability of prey: if prey were lacking, predators were more likely to enter diapause than if prey were abundant. Starved females left the plant system, probably through aerial dispersal, and mated females dispersed more readily than males and virgin females under long daylengths. No differences in aerial dispersal tendency were observed at short photophases. Aerial dispersal of adult females occurred at air speeds of ca. 1.5 m/s.
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 39 (1985), S. 261-264 
    ISSN: 1570-7458
    Schlagwort(e): Agrotis segetum ; Lepidoptera Noctuidae ; biological control ; entomogenous nematodes ; Neoaplectana bibionis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Unter Freilandbedingungen wurde die biologische Bekämpfung von Erdraupen (Agrotis segetum Schiff., Lepidoptera, Noctuidae) mit dem entomophagen Nematoden Neoaplectana bibionis Bovien geprüft. Mit Salat bepflanzte Parzellen wurden mit Erdraupen besetzt. Anschliessend wurde auf die Parzellen N. bibionis, das Insektizid Endosulfan oder Wasser ausgebracht. Die Versuche wurden in Gebieten mit lehmigen und sandigen Böden durchgeführt. Für eine ausreichende Bekämpfung der Erdraupen waren auf dem sandigen Boden 2.5×105 Nematoden/m2 und auf dem lehmigen Boden 1×106 Nematoden/m2 erforderlich. Die Wirkung dieser Behandlungen entsprach der mit Endosulfan.
    Notizen: Abstract Biological control of the soil-inhabitating larvae (cutworms) of Agrotis segetum Schiff. using the entomogenous nematode Neoaplectana bibionis Bovien was investigated under field conditions. Cutworms were introduced to plots planted with lettuce, Lactuca sativa L. After planting and infection with cutworms the plots were treated with either N. bibionis, the insecticide endosulfan or water. The trials were sited on locations with loamy and sandy soil. Adequate control of cutworms was obtained using 2.5×105 nematodes/m2 on sandy soil and 1×106 nematodes/m2 on loamy soil. Effects of these treatments with nematodes were equal to the effect of endosulfan.
    Materialart: Digitale Medien
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 37 (1985), S. 17-31 
    ISSN: 1570-7458
    Schlagwort(e): aerial dispersal ; Metaseiulus occidentalis ; Acarina ; Phytoseiidae ; Tetranychidae ; spider mites ; pesticide resistance ; almonds ; biological control ; genetic improvement ; carbaryl ; western predatory mite ; European red mite ; two-spotted spider mite ; Pacific mite
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé La dispersion aérienne du phytoseïdae, M. occidentalis (Nesbitt), a été estimée comme élément de la lutte contre les populations résistantes aux insecticides établies dans les vergers de Californie. La dispersion maximale s'est produite fin juillet et début a oût en 1982 et 1983. La plupart des prédateurs (et des acariens) quittent les vergers avec les vents dominants du nordouest. Dans le verger, les vents dominants sont moins importants et la dispersion est généralement au hasard. Tant les acariens que les prédateurs se dispersaient au hasard par rapport à la taille des amandiers, mais les relevés sur 24 heures laissent supposer qu'il n'y a pas une distribution aléatoire pendant la journée. La plupart des mouvements aériens se produisirent entre 16 et 22 heures quand HR et vitesse du vent augmentaient et température diminuait. Les acariens et prédateurs ont été piégés sur des panneaux à 200 m du verger.
    Notizen: Abstract Aerial dispersal of the phytoseiid Metaseiulus occidentalis (Nesbitt) was evaluated as a component in managing pesticide-resistant populations established in California almond orchards. Peak dispersal occurred in late July and early August during 1982 and 1983. Most predators (and spider mites) left the orchards on the prevailing winds from the northwest. Within the orchard, the prevailing winds had less influence, and dispersal was usually random. Both spider mites and predators dispersed randomly with regard to height from the almond trees, but data obtained during one 24-h interval suggest they do not disperse randomly throughout the day. Most aerial movements occurred between 16–22 h when relative humidity and wind speeds increased and temperatures decreased. Spider mites and predators were trapped on panels located 200 m from the orchard. A survey of carbaryl resistance levels in M. occidentalis collected from almond orchards surrounding the release sites indicates that carbaryl-resistant M. occidentalis dispersed at least 800 m between 1981–83. However, growers wishing to use the resistant strains should release them in their orchards as natural dispersal appears to be too slow. Migration of native M. occidentalis into the release sites appeared to be sufficiently rare that dilution of carbaryl-resistant populations was minimal during a 2–4 year period.
    Materialart: Digitale Medien
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 37 (1985), S. 33-39 
    ISSN: 1570-7458
    Schlagwort(e): Entomophthora ; Musca domestica ; biological control ; insect pathology ; epidemiology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Mortalitätsrate von Musca domestica nach Behandlung mit Entomophthora muscae Sporen wurde in Laborversuchen in Abhängigkeit von Wirtsalter,-geschlecht und Expositionsdauer festgestellt. Fliegen verschiedenen Alters (14 Tage, 7 Tage, 3 Tage und jünger als 1 Tag) wurden gemeinsam in 237 ml Kartonbehältern gehalten. Die Behälter besassen Netzdeckel, auf denen frisch an einer Entomophthora Infektion gestorbene Fliegen ausgelegt wurden. Auf diese Weise wurden die Versuchstiere 8 Stunden (‘low exposure’) bzw. 48 Stunden (‘high exposure’) lang mit Entomophthora Sporen kontaminiert. Mit Hilfe von am Boden der Versuchsgefässe ausgelegten Objektträgern wurde die relative Menge Entomophthora Sporen festgestellt, der die Versuchstiere ausgesetzt waren. Der Totenfall wurde täglich für die Dauer von 10 Tagen registriert; dabei wurde zwischen Konidienträgern (‘external signs’) und Leichen ohne Konidien (‘no external signs’) unterschieden. Die Versuchsgruppen, die 48 Stunden lang mit Entomophthora Sporen behandelt worden waren, wiesen im Vergleich zu den kürzer behandelten Versuchsgruppen höhere Mortalität und einen höheren Anteil an Konidienträgern auf. Darüber hinaus wurde das Auftreten von Konidienträgern bei den länger behandelten Gruppen früher beobachtet. Im Vergleich zu unbehandelten Kontrollgruppen erhöhte die Behandlung mit Entomophthora Sporen auch die Rate nicht konidientragender Leichen. Bei gleicher Expositionsdauer zeigten Weibchen und Männchen ähnliche Mortalitätsraten. Ein höherer Anteil Konidienträger bei den Weibchen wurde bei einem von zwei entsprechenden Versuchen beobachtet. Konidienträger traten bei Weibchen später als bei Männchen auf. In Bezug auf die Inkubationszeit konnte kein geschlechsspezifischer Unterschied festgestellt werden, wenn Versuchsgruppen mit gleichem Gewicht verglichen wurden. Bei beiden Geschlechtern erfolgte die Bildung von Konidien bei grösseren Individuen später als bei kleineren Individuen. Das Alter der Versuchstiere beeinflusste sowohl die Mortalitätsrate als auch die Häufigkeit und das zeitliche Auftreten von Konidienträgern. Jüngere Fliegen wiesen einen höheren Anteil Konidienträger auf; bei Fliegen mit einem Alter von weniger als einem Tag wurde das Auftreten von Konidienträgern früher beobachtet als bei älteren Individuen. Die untersuchten Faktoren können auch für die Epidemiologie von Entomophthora freilebender Musca domestica Populationen eine wichtige Rolle spielen. In Populationen mit niedrigerem Durchschnittsalter wird sich eine Infektion rascher ausbreiten, da jüngere Fliegen eine kürzere Inkubationszeit aufweisen und auch nach kürzerer Kontaminationsdauer Konidien an den getöteten Individuen ausgebildet werden. Darüber hinaus wird sich eine Infektion dann rascher ausbreiten, wenn die Population mit einer grösseren Sporenmenge infiziert wird, da dann eine kürzere Inkubationzeit und ein höherer Anteil Konidienträger zu erwarten ist.
    Notizen: Abstract Adult Musca domestica were exposed to conidial showers from cadavers that were killed by Entomophthora muscae. Of the 4 host ages (14 days, 7 days, 3 days and 〈1 day), older flies were more likely to die without postmortem signs of infection, while younger flies were more likely to die with signs and produce primary conidia. The youngest fly group also succumbed to infection significantly sooner than older flies. Total mortality did not differ for the 2 sexes, but females died significantly more often with signs in one trial. Males died significantly earlier than did females, but differences were not significant when the sexes were paired by weight. Increased levels of pathogen exposure significantly increased both total mortality and the number of flies dying with signs; it also decreased incubation period. The potential significance of these findings in the epidemiology of the disease is discussed.
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology reporter 17 (1999), S. 323-331 
    ISSN: 1572-9818
    Schlagwort(e): Agrobacterium ; modular vector ; transformation ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Wheat (cv Chinese Spring) tissues were transformed using Agrobacterium tumefasciens and a new plasmid modular vector, pMVTBP. We constructed pMVTBP with unique restriction sites connecting (1) the CaMV 35S promoter, (2) a Kozak sequence, (3) the FLAG epitope, (4) the (His)6 epitope, (5) a coding region (for wheat TATA Binding Protein, wTBP) and (6) the CaMV 35S 3′UTR. This vector thus allows easy exchange of different regulatory or coding sequences. Explants of either germinating mature seeds, or immature embryos, were induced to callus for up to two weeks, treated with virulence-induced bacteria for one hour, then regenerated into plantlets. Transient expression of a GUS reporter gene, assayed at about one week, occurred in 10–12% of calluses. Expression of the FLAG-tagged wTBP was also detected, by immunostaining. Stable expression, by selective growth on geneticin, and by GUS expression at about six weeks, occurred in 1–2% of calluses, quite comparable to that achieved by other methods.
    Materialart: Digitale Medien
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  • 26
    ISSN: 1573-0832
    Schlagwort(e): biological control ; compatible solutes ; Epicoccum nigrum ; polyols ; solid substrate fermentation ; water activity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Epicoccum nigrum conidia were produced by solid fermentation on wheat grains (cv. Rendeveaux and Brigadier) at different water activities (aw). Conidial production was highest at high aw(0.996) than at reduced aw (0.98). However, conidial production at reduced aw was improved when the aw of the substrate was adjusted with a mixture of glycerol and water. Maximum levels ofconidiation were 7–11 × 106 conidia g−1 grain. The aw of the solid substrate affected the pattern of accumulation of compatible solutes in the conidia. Mannitol was the main polyol in all conidialtypes. However, the amounts of mannitol were higher in conidia produced at high aw. At reduced aw the conidia of E. nigrum accumulated moreglycerol, which is more efficient in the osmorregulation proccess than mannitol. Arabitol accumulated in low amounts, specifically in conidia produced at the lower aw, on cv. Rendeveaux but not on cv. Brigadier. Trehalose was detected in higher amounts in cv. Rendeveaux than in cv. Brigadier, andthe amounts were higher in conidia produced at high aw. A significant amount of endogenous solutes was detected in the washing liquid used for the separation of the conidia.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 53 (1999), S. 139-146 
    ISSN: 1573-0867
    Schlagwort(e): critical levels of Mn ; soil extractants ; Mn-deficiency ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Seven chemical extractants were tested for their relative performance to predict the response of wheat to Mn application in coarse textured alkaline soils of semi-arid region. Five out of the seven extractants were found to be promising for the estimation of critical level of available Mn in these soils, as the amount of Mn extracted by these extractants was positively and significantly correlated with relative grain yield as well as Mn uptake. The critical deficiency level of soil available Mn with 0.005 M DTPA, 0.02% hydroquinone, 0.02 N sodium pyrophosphate, 0.1N H3PO4 and 0.05N HCl+0.025N H2SO4 was 3.1, 13.8, 23.5, 5.3 and 17.8 mg kg-1 soil, respectively. The 1N ammonium acetate and 0.01M CaCl2 were found to be unsuitable extractants for these soils. Further field trials at eight locations with varying levels of Mn deficiency showed successive increase in the grain yield of wheat with foliar Mn application, emphasizing the need for Mn fertilization when wheat is grown on Mn deficient soils.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 6 (1985), S. 171-176 
    ISSN: 1573-0867
    Schlagwort(e): Chloride ; phosphorus ; salinity ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A pot study with four levels each P (control, 6.5, 13.0, 19.5 mg kg−1) and Cl− in irrigation water (control, 30, 60, 90me l−1) was carried out to test Cl− and P interaction on wheat. It has been found that optimum P nutrition alleviates the toxic effect of excess Cl−. Highest P rate resulted in a significant yield increase upto a Cl− level of 60me l−1. Cl− depressed P content in the plant only at a Cl− level of 90me l−1, while P rates had no major impact on the Cl− concentration in the plant. Lower Cl− concentration at higher P rates are rather a dilution effect than an antagonistic one. With optimum P supply higher Cl− contents in the plants were tolerated than with a low P supply.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 8 (1985), S. 91-96 
    ISSN: 1573-0867
    Schlagwort(e): chickpea ; Egyptian clover ; field experiments ; K uptake ; mustard ; wheat ; yield
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A field experiment on a potassium deficient Typic ustochrept soil of the University Farm at Pura, Kanpur compared the responses of wheat, chickpea, mustard and Egyptian clover to added potassium for two consecutive years commencing in 1979–80. All the crops responded to potassium fertilization. Sensitivity of various crops to potassium deficiency was in the order: Egyptian clover 〉 chickpea 〉 wheat 〉 mustard. Higher sensitivity of Egyptian clover and chickpea compared to wheat was in agreement with their comparatively high root cation exchange capacity. Mustard by contrast showed higher root cation exchange capacity and exhibited least potassium sensitivity because of its higher potassium utilization efficiency. Leaf K content and total uptake of potassium by all crops was increased by applying potassium upto the highest level.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 8 (1985), S. 173-178 
    ISSN: 1573-0867
    Schlagwort(e): critical limit of Mn ; highly permeable soils ; methods and rates of Mn ; Mn deficiency ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Two field experiments were conducted on Mn-deficient soils to evaluate the efficiency of rates, methods and time of MnSO4.H2 O application for wheat. Manganese sulphate was broadcast and mixed in soils at the rate of 5 to 50kg Mn ha−1 before seeding and 10 to 40 kg Mn ha−1 as top dress at 28 days — just before first irrigation. Three sprays of 1% MnSO4·H2O unneutralised solutions were applied, the first at 26 days — 2 days before first irrigation and the others afterward at weekly intervals. Both the methods caused a significant and marked increase in grain yield. Three foliar sprays were as effective as soil applications of 20 to 40 Kg Mn ha−1 before seeding. The difference in grain yield resulting from soil applications of Mn before seeding and applications at the first irrigation was not significant. The DTPA-Mn status of 20 fields, selected on the basis of varying degree of Mn deficiency, was related to grain yield (r = 0.77**). Also grain yield of all the experiments had a significant correlation with Mn content of grain (r = 0.55** to 0.82**) and straw (r = 0.77** to 0.82**). The critical limits calculated by statistical method were 1.25, 2.18 and 3.5 mg Mn kg−1 soil for severe deficiency, deficiency and latent deficiency respectively for wheat.
    Materialart: Digitale Medien
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  • 31
    ISSN: 1572-9761
    Schlagwort(e): Coccinellidae ; Aphididae ; wheat ; spatial scale ; species diversity ; numerical response
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The influence of prey density, within-field vegetation, and the composition and patchiness of the surrounding landscape on the abundance of insect predators of cereal aphids was studied in wheat fields in eastern South Dakota, USA. Cereal aphids, aphid predators, and within-field vegetation were sampled in 104 fields over a three year period (1988–1990). The composition and patchiness of the landscape surrounding each field were determined from high altitude aerial photographs. Five landscape variables, aggregated at three spatial scales ranging from 2.6 km2 to 581 km2, were measured from aerial photographs. Regression models incorporating within-field and landscape variables accounted for 27–49% of the variance in aphid predator abundance in wheat fields. Aphid predator species richness and species diversity were also related to within-field and landscape variables. Some predators were strongly influenced by variability in the composition and patchiness of the landscape surrounding a field at a particular spatial scale while others responded to variability at all scales. Overall, predator abundance, species richness, and species diversity increased with increasing vegetational diversity in wheat fields and with increasing amounts of non-cultivated lands and increasing patchiness in the surrounding landscape.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Integrated pest management reviews 4 (1999), S. 127-143 
    ISSN: 1572-9745
    Schlagwort(e): wheat ; stored-grain ; integrated pest management ; aeration ; biological control ; grain sampling ; insect monitoring ; modeling ; area-wide IPM
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Management of stored-grain insect pests by farmers or elevator managers should be based upon a knowledge of the grain storage environment and the ecology of insect pests. Grain storage facilities and practices, geographical location, government policies, and marketing demands for grain quality are discussed as factors influencing stored-grain insect pest management decisions in the United States. Typical practices include a small number of grain samples designed to provide grain quality information for segregation, blending and marketing. This low sampling rate results in subjective evaluation and inconsistent penalties for insect-related quality factors. Information on the efficacy of insect pest management practices in the United States, mainly for farm-stored wheat, is discussed, and stored-grain integrated pest management (IPM) is compared to field-crop IPM. The transition from traditional stored-grain insect pest control to IPM will require greater emphasis on sampling to estimate insect densities, the development of sound economic thresholds and decision-making strategies, more selective use of pesticides, and greater use of nonchemical methods such as aeration. New developments in insect monitoring, predictive computer models, grain cooling by aeration, biological control, and fumigation are reviewed, their potential for improving insect pest management is discussed, and future research needs are examined.
    Materialart: Digitale Medien
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Integrated pest management reviews 4 (1999), S. 21-37 
    ISSN: 1572-9745
    Schlagwort(e): carrot weevil ; IPM ; Anaphes spp. ; biological control ; ecology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The carrot weevil, Listronotus oregonensis (LeConte) (Coleoptera: Curculionidae) is a major pest of carrots in northeastern North America. The females oviposit in the leaf petiole and the developing larvae make tunnels in the carrot roots. Exclusive reliance on chemical control and the poor control obtained, prompted, in the early 1980s, research on the ecology and physiology of the pest and its natural enemies. Carrot weevil females start their oviposition by 147±9 DD7°C but they oviposit only in carrots past the 4 true-leaf-stage. As a result, oviposition is delayed, and damage reduced, in late-sown carrots. Monitoring carrot weevil adults in the spring with either carrot root sections or wooden plate traps enables growers to apply control treatments only if the population density justifies it. Egg parasitoids of the genus Anaphes (Hymenoptera: Mymaridae) are the most important natural enemies and they account, in untreated plots, for up to 80% mortality. Their effectiveness could be improved by managing field borders to establish secondary host species. An IPM programme was developed in the 1980s based on the research results obtained and, through regular monitoring, has achieved a substantial decrease in pesticide use.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Integrated pest management reviews 4 (1999), S. 39-52 
    ISSN: 1572-9745
    Schlagwort(e): Scapteriscus ; Neocurtilla ; Gryllotalpa ; biological control ; turf ; pastures ; vegetables
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract There are at least 70 species of mole crickets (Orthoptera: Gryllotalpidae). Some are rare, others are innocuous, and a few are important pests. These soil-dwelling pests damage underground parts of a long list of cultivated plants. Although tillage and flooding are used successfully in some situations to bring these pests to the soil surface and expose them to vertebrate and other predators, chemical pesticides are widely used against them. Knowledge of their life history is used to time application of chemical treatments to save money, but is not used as widely as it might be. Classical biological control has been used against immigrant mole crickets in Hawaii, Puerto Rico, and the southern USA. In Florida, three Scapteriscus species from South America cause major damage to pastures and turf and are targets of a classical biological control program. Population levels of two of the pest species have been reduced substantially in Florida by establishment of a tachinid fly (Ormia depleta) and a steinernematid nematode (Steinernema scapterisci) from South America. The nematode also functions as a biopesticide. Managers of pastures and turf in Florida have thus far derived benefit from these classical biological control agents without understanding their function: use of chemicals is reduced when mole cricket populations are lower due to action of these organisms. Future enhancement of the action of O. depleta and of a sphecid wasp (Larra bicolor, which also was introduced from South America) probably will demand deliberate planting of nectar sources for adults of these biological control agents, and the advantage will be to managers who adopt such a strategy. Chemical pesticide use is strongly promoted by a large chemical industry, whereas biopesticidal use has thus far been little promoted and sales have been few. Even managers who do not change their simple strategy of pesticide use in response to damage by mole crickets, and have no knowledge of the differing life cycles of the three Scapteriscus species or of the presence and action of the classical biological control agents, will derive benefit as these biological control agents (and a predatory beetle which has not yet been released) increase their distribution.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Integrated pest management reviews 4 (1999), S. 97-126 
    ISSN: 1572-9745
    Schlagwort(e): agriculture ; biological control ; campaign ; chemosterilent ; commensal ; control methods ; economics ; environmental and cultural methods ; horticulture ; India ; pest management ; pre- and post-harvest crop losses ; poultry farms ; rodent ; rodenticide ; South Asia ; trapping
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Eighteen species of rodents are pests in agriculture, horticulture, forestry, animal and human dwellings and rural and urban storage facilities in India. Their habitat, distribution, abundance and economic significance varies in different crops, seasons and geographical regions of the country. Of these, Bandicota bengalensis is the most predominant and widespread pest of agriculture in wet and irrigated soils and has also established in houses and godowns in metropolitan cities like Bombay, Delhi and Calcutta. In dryland agriculture Tatera indica and Meriones hurrianae are the predominant rodent pests. Some species like Rattus meltada, Mus musculus and M. booduga occur in both wet and dry lands. Species like R. nitidus in north-eastern hill region and Gerbillus gleadowi in the Indian desert are important locally. The common commensal pests are Rattus rattus and M. musculus throughout the country including the islands. R. rattus along with squirrels Funambulus palmarum and F. tristriatus are serious pests of plantation crops such as coconut and oil palm in the southern peninsula. F. pennanti is abundant in orchards and gardens in the north and central plains and sub-mountain regions. Analysis of the information available on the damage and economic losses caused by rodents in rice, wheat, sugarcane, maize, pearl millet, sorghum, oil seed, legume and vegetable crop fields, horticulture and forestry, poultry farms, and rural and urban dwellings and storage facilities clearly shows that chronic damage ranging from 2% to 15% persists throughout the country and severe damage, sometimes even up to 100% loss of the field crop, is not rare. Several traditional and modern approaches and methods of rodent control are being used. The existing knowledge of the environmental, cultural, biological, mechanical and chemical methods of rodent control in India is reviewed. Considerable variations exist in the susceptibility of the pest species to different methods, particularly to rodenticides and trapping, their field applicability, efficacy and economics in different crops, seasons and geographical regions, behavioural responses of the pest species to these methods in different ecological conditions and their adoption by farmers in different regions of India. Environmental and cultural techniques, such as clean cultivation, proper soil tillage and crop scheduling, barriers, repellents and proofing which may reduce rodent harbourage, food sources and immigration have long lasting effects but are seldom adopted. However, their significance in relation to normal agricultural practices, intensification and diversification are discussed. Rodenticides, which provide an immediate solution to the rodent problem, form the major component of rodent control strategies in India. Poison baiting of rodents with zinc phosphide and burrow fumigation with aluminium phosphide are common in agricultural fields and recently Racumin (coumatetralyl) and bromadiolone have been introduced for the control of both agricultural and commensal rodent pests in India. Methods and timings of campaigns and successes and problems in implementation of rodent control are also reviewed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Integrated pest management reviews 4 (1999), S. 307-312 
    ISSN: 1572-9745
    Schlagwort(e): microbial control ; biological control ; biopesticide ; mycopesticide ; Metarhizium ; Beauveria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Microbial control agents generally kill insects more slowly than chemical pesticides, and fast-moving migratory pests may not at first sight appear to offer the most promising targets for microbial control. Operators responsible for control may need to have recourse to chemical control agents. Nevertheless, there are many occasions when pests breed and feed outside the crop and a microbial control agent can be used. Similarly, immature stages may cause little damage and early treatment in the crop can avoid damage. Microbial control agents are particularly likely to be favoured if the pest breeds in a conservation area, and if a publicly-accountable agency is responsible for control. Other key points of importance are the IPM context, in particular detection, planning and forecasting of outbreaks and the role of natural enemies. With these points in mind, we identify several locust and grasshopper systems where microbial control is becoming established; additionally, Sunn pest of wheat and Armyworm are identified as promising situations forbreak microbials.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Journal of the history of biology 32 (1999), S. 509-555 
    ISSN: 1573-0387
    Schlagwort(e): Louis Agassiz ; Spencer Baird ; Charles Girard ; reputation ; taxonomy ; ichthyology ; Museum of Comparative Zoology ; Smithsonian Institution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geschichte
    Notizen: Abstract The reputations of scientists among their contemporaries depend not only on accomplishment, but also on interactions affected by influence and personality. The historical lore of most fields of scientific endeavor preserve these reputations, often through the identification of founders, innovators, and prolific workers whose contributions are considered fundamental to progress in the field. Historians frequently rely on the historical lore of scientists to guide their studies of the development of ideas, exhibiting justifiable caution in reassessing reputations in the light of current knowledge. However, the transmission of historical lore can obscure the relative importance of accomplishment, influence and personality in shaping contemporary reputations, leaving the historian to either accept reputations at face value or attempt to reconstruct the context in which they were created. The science of taxonomy, because of its rules of priority, leaves a relatively accurate record of historical accomplishment through the persistence of taxa in catalogues and faunal guides. These records allow the modern historian an unbiased means to assess the relative accomplishments of historical figures and therefore a means to critically reassess reputations independent of personality and influence. In the historical lore of North American ichthyology, Louis Agassiz at Harvard and Spencer Baird at the Smithsonian emerge as central figures in the early development of the field during the mid-1800s, contributing not only through the quality and quantity of their science, but also through their roles as institutional leaders and mentors to workers who followed. Charles Girard, originally a student of Agassiz's and later a coworker with Baird, receives little notice in the history of ichthyology, and his reputation is that of a minor player in the initial description of the North American fish fauna, and one whose work appears to have been flawed or even careless when compared to his contemporaries. However, a review of both contemporary and modern taxonomic works reveals that Girard's productivity far exceeded that of either Agassiz or Baird. Furthermore, an examination of the tendency of Girard and his contemporaries to introduce synonymous names into the literature, which might reflect careless or uncritical work, suggests that Girard was among the more accomplished workers of hisera, including Agassiz and Baird. Girard's low ranking in the folklore of North American ichthyology, therefore, can not be attributed to discernible shortcomings in his scientific work, but rather to a public and private campaign of criticism waged by Agassiz after Girard's departure from Harvard. While Agassiz's dispute with Girard stemmed from their personal interactions, he expressed them as criticisms of Girard's work, and thus helped shape Girard's scientific reputation as it has been transmitted through the lore of ichthyology. This case study reveals how scientific reputation may not always rest on accomplishment, but can be influenced by personal interactions obscured by time but nonetheless important to history.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 194 (1985), S. 429-432 
    ISSN: 1432-041X
    Schlagwort(e): Tail bud ; Tail gut ; Gut ; Organogenesis ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The formation of the tail portion of the primitive gut was investigated by light and electron microscopy in 10- and 11-day rat embryos. The observations permit the conclusion that the tail gut does not form as a posterior extension of the hindgut but originates from the tail bud mesenchyme by mechanism analogous to the secondary neurulation. It includes cell condensation, aquisition of apicobasal polarity and the radial, rosette-like arrangement around a central cavity. These cells bear the cytological characteristics of both the absorptive epithelial cells and the mesenchymal cells at their apical (adluminal) and abluminal ends respectively.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 41 (1985), S. 282-283 
    ISSN: 1420-9071
    Schlagwort(e): Hydra ; chromosomes ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A simple method to prepare chromosome spreads of hydra is described. Chromosome counts for a non-symbiotic ‘brown hydra’,Hydra vulgaris attenuata, and the Swiss strain of a symbiotic ‘green hydra’ indicated a diploid number of about 2n=30 in each case. It is suggested that chromosome number may be used to define hydra species more precisely.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 40
    ISSN: 1420-9071
    Schlagwort(e): Rat ; alloxan diabetes ; intestinal villus ; alkaline phosphatase ; sucrase ; epithelial cells ; villus-crypt axis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The sucrase activity in enterocytes isolated from the villus crypt axis was found to increase in all regions of the villus from day 2 after induction of diabetes, and the increase continued until day 4. In contrast, alkaline phosphatase activity increased mainly in the apical one-third of the villus-crypt column, and the increase occurred abruptly on day 4 with increase in food intake.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 41 (1985), S. 273-275 
    ISSN: 1420-9071
    Schlagwort(e): Rat ; embryo ; embryo ; rat ; β-hydroxybutyrate ; diabetes ; maternal ; fetal malformation ; malformation ; fetal ; ketone bodies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In order to investigate further the relationship between maternal diabetes and fetal malformation, rat embryos were grown in vitro in the presence of β-hydroxybutyrate, one of the ketone bodies produced by diabetics. At 10 mM, β-hydroxybutyrate produced minor abnormalities and at 20 mM it produced major abnormalities in rat embryos.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 41 (1985), S. 441-446 
    ISSN: 1420-9071
    Schlagwort(e): Methanogenic bacteria ; Archaebacteria ; classification ; physiology ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 43
    ISSN: 1432-1211
    Schlagwort(e): Key words Class II MHC sequence ; Rat ; Cloning ; RT-PCR ; Polymorphism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 44
    ISSN: 1573-1561
    Schlagwort(e): Allelopathy ; gamma irradiation ; Sorghum bicolor ; Amaranthus retroflexus ; nitrification ; biological control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The effect of low doses of gamma irradiation on the allelopathic potential ofSorghum bicolor against weeds and nitrification was investigated. The results revealed that all test doses (500, 1000 and 1500 rad) significantly increased the allelopathic activity of root exudates, aqueous extracts, and decaying residues aganst seed germination and seedling growth ofAmaranthus retroflexus. The results also indicated that all test doses stimulated the allelopathic potential of aqueous extracts and decaying residues against nitrification activity. The possible application of this approach in biological control is briefly discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 25 (1999), S. 1555-1565 
    ISSN: 1573-1561
    Schlagwort(e): Yeasts ; Botrytis cinerea ; apple ; volatiles ; gray mold ; biological control ; fungal interaction ; acetate esters
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The fungus, Botrytis cinerea, causes decay in apples in postharvest storage. Conidia of B. cinerea on polycarbonate membranes were incubated on filter paper disks saturated with water or suspensions of yeasts (2 × 106 CFU/filter) and then exposed for 24 hr at 22°C to 0–16 μl of ethyl, butyl, or hexyl acetates injected into the headspaces of 500-cc glass jars. Germination of conidia was increased by exposure to 4–16 μl of ethyl acetate compared to the no-ester controls. Conidia were stimulated to germinate by 4 μl of butyl acetate and 8 μl of hexyl acetate, but greater volumes were toxic to germination. The yeasts Cryptococcus laurentii and Sporobolomyces roseus were more effective at reducing the stimulatory effect than Saccharomyces cerevisiae. Acetate esters also stimulated germination of conidia on polycarbonate membranes on apples inside jars. Cryptococcus laurentii or S. roseus suppressed this effect more than S. cerevisiae. Germination of conidia on a membrane on water inside a 3.9-liter jar containing an apple was 2.5-fold greater than the no-apple control. Butyl acetate increased Botrytis infection of apple wounds. Butyl and hexyl acetate were detected by GLC in the headspace of Golden Delicious apples. Results indicated that some acetate esters produced by apple stimulated germination of B. cinerea conidia, and this effect was suppressed by yeasts.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 239 (1985), S. 3-8 
    ISSN: 1432-0878
    Schlagwort(e): GnRH receptors ; Gonadotropes ; Coated pits ; Internalization ; High-resolution autoradiography ; LHRH, Gonadoliberin ; Pituitary gland ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Localization of GnRH receptors in rat pituitary gonadotropes was studied by use of 125I-[azidobenzoyl-D-Lys6]GnRH which, upon photolysis, is covalently bound to the receptor molecule. Using high resolution autoradiography, it was found that, after a 90-min incubation of the analog with pituitary cells at 4° C, 93% of the silver grains were associated with the plasma membrane of the gonadotropes. After 45-min incubation of the cells at 37° C, clustering and internalization of the receptor-bound GnRH analog were evident. Silver grains were associated with coated pits, intracellular vesicles, Golgi complexes, lysosome-like structures and secretory granules. The data indicate that receptor-bound GnRH agonist is internalized, at least in part, via coated pits and is subsequently routed to lysosomes where degradation of the hormone-receptor complex may occur. The presence of a considerable amount of silver grains associated with secretory granules may suggest that some of the internalized receptor molecules can escape degradation and be recycled to the cell membrane.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 239 (1985), S. 31-35 
    ISSN: 1432-0878
    Schlagwort(e): Lymph filtration ; Antigen and antibody distribution ; Subcapsular sinus ; Lymph node ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A recent study of lymph nodes of the rat showed that they are morphologically and physiologically compartmentalized. A compartment of a node includes a portion of subcapsular sinus into which the lymph, entering via the related afferent lymphatic opening, is filtered. The study also showed that colloidal carbon injected locally in a small dose becomes predominantly associated with the areas of the inner wall of the subcapsular sinus that cover the extrafollicular zone of the peripheral cortex. Little carbon is seen over the folliculo-nodules (follicles with a nodule or germinal center). The question arose as to whether drained natural substances, as antigens and antibodies, follow the same pattern of distribution in the subcapsular sinus as the carbon. Therefore, small doses of fluorescein isothyocyanate (FITC)-conjugated antigens were injected locally into normal rats whose own antibodies in the nodes were stained by immunofluorescence. The pattern of distribution of the antigens in the draining nodes was found to be the same as that of the carbon. Furthermore, the lymph-carried antibodies of the rats were found to follow the same pattern. The morphological basis for such a pattern is explained. The results are further discussed with regard to the probable normal entry route of lymph-carried antigens in the parenchyma of nodes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 239 (1985), S. 137-140 
    ISSN: 1432-0878
    Schlagwort(e): Lanthanum ; Odontoblasts ; Tight junctions ; Tooth pulp ; Ultrastructure ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Odontoblasts are known to be involved in the process of dentinogenesis but it is not clear whether substances may also be deposited in predentine and dentine by passing between these cells. Although tight junctions have been described, it is not clear if they are macular or “leaky” as opposed to continuous or “tight”. In this study use has been made of the permeability of fenestrated capillaries amongst the odontoblasts to deposit the penetrative tracer lanthanum in the interodontoblastic space. This was done by perfusion of anaesthetized rats with physiological solutions containing lanthanum nitrate at 37° C. Immersion fixation of transverse segments of mandibular incisors and examination with an electron microscope showed that lanthanum could permeate 40–50 μm between the odontoblasts to reach the peripheral pulp. Towards the predentine, often less than 10 μm from the capillaries, its progress was abruptly and completely halted by the junctions at the apical ends of the odontoblast cell bodies. Lanthanum was not found in the predentine. The mature secretory odontoblasts in the rat incisor have therefore been shown to be joined by continuous tight junctions. In the process of dentinogenesis this means that all substances deposited in predentine and dentine must arrive by passing through the odontoblasts.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 239 (1985), S. 183-188 
    ISSN: 1432-0878
    Schlagwort(e): Fenestrations ; Basal lamina ; Intestine, small ; Immune system ; SEM ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Fenestrations of the basal lamina of rat intestinal villi were revealed by scanning electron microscopy after removal of the overlying epithelial cells by osmic acid maceration. These fenestrations are circular to oval in shape and are 0.5 μm to 5 μm in diameter. They are richly distributed at a density of 1–2x104/mm2 in the upper two thirds of the villi, except at the very tips. Roughly 500 fenestrations are found on each side of an average sized tongue-shaped villus. Transmission electron-microscopic observations showed that these fenestrations were passages for migrating cells of the immune system such as lymphocytes, eosinophils and macrophages. Protrusions from the basal parts of epithelial cells were also observed passing through these fenestrations. These findings are discussed with respect to their immunological implications and to the passage of nutrients.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 239 (1985), S. 293-298 
    ISSN: 1432-0878
    Schlagwort(e): Acid phosphatase cytochemistry ; Lysosomes ; Synovial membrane ; Synoviocytes ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The lysosomal system of the two types of synoviocytes (A and S) from the knee joint of normal rat synovial membrane was studied by electron-microscopic acid phosphatase cytochemistry. In random sections of the synovial intima lysosomes were more often encountered in the A-cell profiles than in the S-cell profiles. Characteristically, type-A synoviocytes showed many large and medium-sized lysosomes the cytochemical appearance of which varied considerably. No acid phosphatase activity was detectable in the cisternae of the Golgi apparatus or in the Golgi vesicles. In type-S synoviocytes the lysosomes were smaller, and more uniform in cytochemical appearance. Heavy deposits of acid phosphatase reaction product were constantly demonstrated in cisternae of the Golgi apparatus as well as in smooth-walled Golgi vesicles in type-S cells. The findings that type-A and type-S synoviocytes show distinctly different organization of the lysosomal system indicate that the roles of the lysosomes in these two types of cells may be different.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 296 (1999), S. 235-246 
    ISSN: 1432-0878
    Schlagwort(e): Key words Transplantation ; Parkinson’s disease ; CNS fetal development ; CNS differentiation ; Neurotrophic factors ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract We have previously shown that a combination of the cytokines interleukin (IL)-1, IL-11, leukemia inhibitory factor (LIF), and glial cell line-derived neurotrophic factor (GDNF) can convert rat fetal (E14.5) mesencephalic progenitor cells into tyrosine hydroxylase (TH)-immunoreactive (ir) neurons in vitro. The experiments described here characterize the mesencephalic progenitor cells and their cytokine-induced conversion into dopamine (DA) neurons. For all experiments, we used bromodeoxyuridine (BrdU)-ir cultures of (E14.5) mesencephalic progenitor cells that had been expanded at least 21 days. We first demonstrated that IL-1 induced DA neuron conversion in mesencephalic progenitors, but not in striatal progenitors (P〈0.001). Thus, these cells should be classified as lineage-restricted progenitors, and not omnipotent stem cells. To further characterize cell populations in these cultures, we used monoclonal antibodies against Hu (an early marker for neurons), growth-associated protein (GAP)-43 (a marker for neuronal process extension), TH (a marker for DA neurons), and glial fibrillary acidic protein (GFAP, a marker for astrocytes). We assessed (E14.5) mesencephalic progenitor cell cultures (plated at 125,000 cells/cm2) incubated in the cytokine mixture (described above) or in complete media (CM, negative control). Following 7 days incubation, GFAP-positive cells formed a nearly confluent carpet in both types of cultures. However, numbers of Hu-ir and GAP-43-ir cells in the cytokine-incubated cultures far exceeded those in CM-incubated controls (P=0.0003, P=0.0001, respectively), while numbers of TH-ir cells were 58-fold greater in the cytokine-incubated cultures versus CM-incubated controls. The TH phenotype persisted for 7 days following withdrawal of the differentiation media. Numerous double-labeled cells that were BrdU-ir and also TH-ir, or Hu-ir and also TH-ir, were observed in the cytokine-incubated cultures. These data suggest that cytokines ”drive” the conversion of progenitor cells into DA neurons.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 239 (1985), S. 651-655 
    ISSN: 1432-0878
    Schlagwort(e): Gap junctions ; cAMP ; Liver ; Freeze-fracturing ; Morphometry ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Since cAMP has recently been reported to be a possible physiological modulator of cell-to-cell communication, we performed a quantitative freeze-fracture investigation on the hepatocyte gap junctions after administration of a membrane-permeant derivative of this cyclic nucleotide. For this purpose, male rats received two intraperitoneal injections of 100 mg dibutyryl cAMP/kg body weight with a time interval of 2.5 h. Litter mates were injected with saline only. Five hours after the start of the treatment, tissue blocks of the left lateral liver lobe were fixed by immersion and processed for freeze-fracture. By point counting on negatives projected on a square double-lattice test system the relative gap junctional area on contiguous hepatocyte membranes was determined. As compared to control animals, the proportion of the membrane area occupied by gap junctions in dibutyryl cAMP-treated liver parenchyma significantly increased from 4.9% to 6.1%. Within the gap junctions no changes in shape, particle density or packing pattern were observed. Possibly, the enlarged gap junctional area provides structural pathways for the integration of the response of hepatocytes to messages mediated by cAMP.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 239 (1985), S. 131-136 
    ISSN: 1432-0878
    Schlagwort(e): Capillary permeability ; Lanthanum ; Peripheral nerves ; Tooth pulp ; Ultrastructure ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Experiments were performed to compare the permeability of capillaries supplying the endoneurial environment, which is invested by perineurium, with vascular permeability in the pulp where perineurium is absent. Anaesthetised rats were perfused through the aorta with physiological solutions containing lanthanum nitrate at 37° C. Pieces of inferior alveolar nerve and segments of mandibular incisors were immersion-fixed and transverse sections were examined electron microscopically for the distribution of lanthanum. In the pulp the nerve fibres pass between lanthanum-impermeable arterioles and venules en route to the incisal end. In the peripheral pulp a few capillaries were permeable but the most permeable capillaries lay between the odontoblasts. Pulpal capillary permeability was attributed to the fenestrated endothelium and contrasted with the unfenestrated endoneurial capillaries which were impermeable to lanthanum. Whereas the tight junctions of endoneurial capillaries are known to prevent certain blood-borne substances from entering the endoneurium, it was not clear whether the permeability of the pulpal capillaries, which are distant from the nerve fibres, could affect the nerve fibre environment. No extravasated lanthanum reached the pulpal nerve fibres suggesting that they are not affected. Technically it was not possible to examine the incisal third of the tooth where the situation could be different because the volume of the pulp decreases and capillaries lie closer to the nerve fibres.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 54
    ISSN: 1432-0878
    Schlagwort(e): Neuropeptides ; Autonomic denervation ; Neuropeptide Y ; Vasoactive intestinal polypeptide (VIP) ; Substance P ; Urinary bladder ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The origin and distribution in the urinary bladder of nerve fibers containing neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP) and substance P (SP) were investigated in rats. Experimental procedures comprised preganglionic decentralization or postganglionic denervation of the bladder and also chemical sympathectomy as well as capsaicin treatment of newborn rats. Nerve fibers containing NPY were richly distributed in the detrusor muscle and also in the pelvic ganglia. Numerous NPY-containing nerve cell bodies were found in pelvic ganglia. A rich occurrence of VIP fibers and a more sparse distribution of SP-containing fibers were also found in the bladder as well as a relatively rich representation of VIP- containing nerve cell bodies in the pelvic ganglia. After decentralization the intensity of VIP and NPY immunofluorescence increased in nerve cell bodies of the pelvic ganglia and in nerve fibers in the wall of the bladder. Postganglionic denervation, on the other hand, eliminated all peptides examined in the bladder wall. After postganglionic denervation the situation in the ganglia was approximately the same as after decentralization. Chemical sympathectomy (6-OHDA) did not seem to change significantly the frequency and distribution of VIP-, SP- and NPY-fibers in the muscle layer of the bladder or in the pelvic ganglia, while the NPY-containing nerve fibers in the submucosal layer and around blood vessels of the bladder disappeared. Adrenergic nerve fibers in the wall of the bladder (visualized by histofluorescence) were markedly reduced in number after administration of 6-OHDA. Capsaicin-treatment of newborn rats caused a loss of SP-fibers in the wall of the bladder, supporting the view that these fibers are sensory in nature in the urinary bladder. Although it cannot be entirely excluded that NPY-containing fibers in the wall of the bladder are adrenergic, the present results suggest that the NPY-fibers as well as the VIP-fibers of the bladder wall originate mainly in non-adrenergic cell bodies of the pelvic ganglia. However, perivascular NPY-containing nerve fibers are adrenergic in nature.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 239 (1985), S. 177-182 
    ISSN: 1432-0878
    Schlagwort(e): Lymphoid tissue ; Lung ; Bronchi ; Immuno-histochemistry ; Enzyme histochemistry ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Immunohistochemical, enzyme-histochemical and electron-microscopical methods were used to study non-lymphoid cells of control and stimulated rat bronchus associated lymphoid tissue (BALT) in situ and in suspensions. Particular attention was paid to the so-called antigenhandling cells, i.e., the interdigitating cells (IDC), which are situated in the T-cell areas, the follicular dendritic cells (FDC), which appear to be restricted to germinal centers, and macrophages, present both in T-cell and B-cell areas. The interdigitating cells were distinguished by being Ia-positive and by the presence of acid phosphatase and non-specific esterase activity in an area near the nucleus. Follicular dendritic cells could be observed in situ by using a monoclonal antibody and by the in vitro trapping of HRP-anti-HRP complexes. Several types of macrophages were found. At the electron-microscopical level no well-developed IDC and FDC could be detected in control BALT. However, in BALT of lipopolysaccharide-stimulated and mycoplasma-infected rats, well-developed IDC and FDC were found. It can be concluded that IDC's and FDC's can be found in BALT.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 239 (1985), S. 405-415 
    ISSN: 1432-0878
    Schlagwort(e): Testis ; Leydig cell ; FSH ; Morphometry ; Ultrastructure ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The effects of FSH on the testicular interstitial tissue of immature hypophysectomized rats were studied by comparing morphological changes in Leydig cells with quantitative changes in interstitial tissue histology using morphometric analysis. Three groups of rats received subcutaneous injections of 0.5 ml saline vehicle or 10 μg rFSH or 20 ng oLH (equivalent to the amount of LH known to contaminate the FSH), twice daily for 7 days. Administration of FSH significantly increased testis weight and stimulated more advanced spermatogenesis compared to saline or LH. Morphometric analysis of testes of LH-treated rats showed a small but significant increase in total interstitial cell volume compared to saline treatment. FSH caused much greater increases in the total volume of interstitial tissue and interstitial cells than either saline or LH and significantly increased the total volume of interstitial fluid by comparison with the other groups. FSH but not saline or LH treatment resulted in a striking hypertrophy of Leydig cells, to produce cells ultrastructurally identical to Leydig cells from adults. Since the target tissue of FSH is the seminiferous epithelium, the observed effects on Leydig cells by FSH treatment suggest that the secretion of factors by the seminiferous tubules may mediate the maturation of Leydig cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 57
    ISSN: 1432-0878
    Schlagwort(e): Trachea ; Basal lamina ; Anchoring fibril ; Ruthenium red-positive filaments ; New anchoring device ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The structural relationship between the basal lamina and the underlying reticular tissue was studied, with special attention to the relationship among basal lamina-associated anchoring fibrillar (AF) arcs (Kawanami et al. 1978, 1979) and other fibrillar components, in the epithelium-denuded trachea of the rat. Quantitative analysis of a large number of AF arcs reveals that the majority of the AF arcs has no other fibrillar components of passage. This suggests that most AF arcs do not serve as a real anchoring device, connecting the basal lamina with the underlying reticular tissue, as has so far been suggested by Kawanami et al. (1978). Ruthenium-red staining reveals the presence of a unique meshwork of microthread-like filaments connecting the undersurface of the basal lamina or the AF arcs with the underlying fibrillar components with a remarkable continuity, suggesting that the filaments act as a real anchoring device; these filaments link, instead of the AF arcs, the basal lamina, to the subjacent reticular tissue. Various enzymatic treatments of the filaments indicate that their chemical nature is probably non-collagenous (glyco)protein without glycosaminoglycan moieties.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 58
    ISSN: 1432-0878
    Schlagwort(e): Key words Subcommissural organ ; Isograft ; Xenograft ; Reissner’s fiber ; Cerebrospinal fluid ; Rat ; Bovine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  The subcommissural organ (SCO) secretes glycoproteins into the cerebrospinal fluid (CSF) that aggregate and form Reissner’s fiber (RF). The factors involved in this aggregation are not known. One factor may be the hydrodynamics of the CSF when flowing through the aqueduct. This hypothesis was tested by isografting rat SCO and xenografting bovine SCO into the lateral ventricle of rats. Xenografts were either fresh bovine SCO or explants cultured for 30 days before transplantation. The grafts were investigated by electron microscopy and immunocytochemistry using antibodies against RF glycoproteins, serotonin and the glucose transporter I. Maximal time of transplantation was 43 days for isografts and 14 days for xenografts. The isografts were not reinnervated but were revascularized; they secreted into the ventricle RF glycoproteins that became progressively packed into pre-RF and RF structures identical to those formed by the SCO in situ. RF was confined to the host ventricle and at its distal end the constituent proteins disassembled. Xenografts were neither reinnervated nor revascularized and secreted into the host ventricle a material that never formed an RF. These findings indicate that the CSF factor responsible for the formation of RF is species specific, and that this process does not depend on the hydrodynamics of the CSF. The blood vessels revascularizing the isografted SCO acquired the characteristics of the vessels irrigating the SCO in situ, namely, a tight endothelium displaying glucose transporter I, and a perivascular space containing long-spacing collagen, thus indicating that basal release of glycoproteins may also occur in the grafted SCO.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 239 (1985), S. 37-42 
    ISSN: 1432-0878
    Schlagwort(e): Subcapsular sinus ; Subsinus layer ; Peripheral cortex ; Lymph node ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The peripheral cortex of a lymph node consists of folliculo-nodules (follicles with a nodule or germinal center) and an extrafollicular zone. In the course of an analysis of the nodes in rats under various experimental or abnormal conditions, our attention became focused on the particularities of a thin layer of peripheral cortex underlying the subcapsular sinus. The present paper reports on observations which led to the identification of the “subsinus layer” of the peripheral cortex. The observations suggest that this layer complements the activity of the inner wall of the subcapsular sinus. The layer probably contributes to the selection of certain elements from the afferent lymph and guides them towards the node area where they can join the cell population involved in the immunological activity in which they are to participate.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 60
    ISSN: 1432-0878
    Schlagwort(e): Pancreatic acini ; Secretion ; Amylase ; Secretagogues ; Receptors ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Incubation of rat pancreatic lobules for 90 min with optimal concentrations of caerulein, carbachol or secretin caused the release of about 30% of the amylase content. Combination of secretin with carbachol or caerulein increased the amylase output to about 40%. With secretin, as with carbachol or caerulein, heterogeneity of cellular responsiveness was observed, some acini being partially or completely depleted of their zymogen granules, whereas others appeared to be resting. When secretin was combined with carbachol or caerulein, granule depletion, originally confined to small groups of neighbouring acini, spread to form large areas of degranulated cells, sometimes comprising a whole section of a lobule. In dispersed acini, under the same conditions, carbachol caused the release of about 60% of the amylase content, and secretin 40%. When both secretagogues were combined, a significant increase to 78% was observed. Under these conditions, there was some important cellular damage, as indicated by the release of 20% of the amylase content and between 6 and 12% of lactate dehydrogenase into the media, in the absence of stimulus. These results were corroborated by cytological observations. On the basis of their secretory response two groups of acini can be distinguished, those that respond to carbachol, caerulein or secretin and those that respond to the combination of secretin with carbachol or caerulein. Electrophoretic patterns of secretory proteins released by lobules stimulated by these different types of secretagogues were essentially similar. The pattern was quite different, however, in the absence of a stimulus. The most striking feature was the presence of a band at 63 Kd whereas a 73.5 Kd band was found only under conditions of stimulation. The latter results support the view that under resting and stimulated conditions secretory proteins are released from distinct compartments in the acinar cell.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 239 (1985), S. 229-233 
    ISSN: 1432-0878
    Schlagwort(e): Chemotherapy ; Vincristine ; Constipation ; Mucosa ; Regulatory peptides ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The microtubule-disrupting drug vincristine is a common component of anti-cancer chemotherapeutic regimes, which produces acute constipation as a side effect. Although generally attributed to damage to the myenteric plexus, the precise mechanism of this disturbance is unknown. In addition, vincristine causes marked aberrations in the secretory response of pancreatic endocrine tissue in both man and rats. No information is available on its possible effect on regulatory peptides of the gastrointestinal tract. In this study we have produced vincristine-induced constipation in rats at a dosage comparable with that employed in the treatment of human subjects. Immunocytochemistry revealed concomitant disturbances in cells exhibiting immunoreactivity for gastrin in the antrum, for gastric inhibitory polypeptide and 5-hydroxytryptamine in the duodenum, for enteroglucagon in the colon, and for somatostatin in all three sites. These widespread effects are transient in nature with normal cell numbers and morphology being reestablished within 6 days. It is suggested that the observed effects are a direct result of microtubule disruption and that gastrointestinal regulatory peptide and amine immunoreactive cells have a rapid regeneration potential.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 62
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 239 (1985), S. 235-239 
    ISSN: 1432-0878
    Schlagwort(e): Erythropoiesis ; Autophagy ; Mitochondria ; Electron microscopy ; Stereology ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Late erythroblasts and reticulocytes from bone marrow of male Wistar rats were studied by electron-microscopic stereology. Late erythroblasts with morphological signs of nuclear extrusion (EN+erythroblasts) and late erythroblasts without these signs (EN-erythroblasts) were analysed separately. The volumes of mitochondria, autophagosomes, autophagocytosed mitochondria, autophagocytosed cytoplasm and degraded material inside autophagosomes were calculated per unit volume of cytoplasm. The results demonstrate that (1) the volume density of mitochondria in the cytoplasm decreases by 34% during maturation from (EN-)- to (EN+)-erythroblasts (p〈 0.001) and by 60% during differentiation from (EN+)-erythroblasts to reticulocytes (p〈0.001), (2) a fivefold increase in the volume density of autophagosomes in the cytoplasm is noted during maturation from (EN-)- to (EN+)-erythroblasts (p〈0.01), whereas the value of this parameter remains essentially unchanged during the subsequent differentiation to reticulocytes, (3) no mitochondria are found inside autophagosomes of (EN-)-erythroblasts, whereas mitochondria occupy 26% and 35%, respectively, of the autophagosomal volume in (EN+)-erythroblasts and in reticulocytes. Our results show that autophagocytosis of mitochondria starts at the moment of nuclear extrusion and continues in the bone marrow reticulocytes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 239 (1985), S. 547-553 
    ISSN: 1432-0878
    Schlagwort(e): Endochondral bone development ; Osteoblast ; Osteoclast ; Horseradish peroxidase ; Electron microscopy ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary To investigate the mechanisms whereby bone cells absorb organic bone-matrix components during endochondral bone development, rat humeri were examined, employing horseradish peroxidase as a soluble protein tracer. Intravenously-injected peroxidase filled the osteoid layer and penetrated into the osteocyte lacunae and canaliculi, but did not enter the mineralized bone matrix. Whereas osteocytes rarely took up exogenous peroxidase, osteoblasts and osteoclasts actively endocytosed peroxidase in pinocytotic coated vesicles, tubular structures, and vacuoles. They also formed endocytotic vacuoles containing peroxidase in the Golgi area. The Golgi apparatus and dense bodies of these bone cells were, however, free of reaction products. Osteoclast ruffled borders were responsible for peroxidase absorption. In the osteoblast, osteocyte and osteoclast, endogenous peroxidatic reaction was detected only in mitochondria and not in other membrane-bounded vesicles and bodies. These results strongly suggest that both osteoblasts and osteoclasts participate in the resorption of bone-matrix organic components during bone remodelling.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 239 (1985), S. 627-631 
    ISSN: 1432-0878
    Schlagwort(e): Thyroidectomy ; Cerebellum ; Coated pit ; Mossy fiber terminal ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The influence that thyroid hormones have on the development of the cerebellar cortex is well known. Their absence in adults leads to important functional changes probably related to abnormalities in nerve terminal activity, although no morphological alterations have hitherto been described. Using ultrastructural morphometric methods, we have studied the effects of thyroidectomy on the cerebellar cortex mossy fiber terminals of adult rats with different survival periods. No significant changes in the volume and surface area of these terminals were found. The numbers of synaptic vesicles in groups 7, 15 and 30 days after thyroidectomy were significantly greater than in controls. A significant increase in coated pit formation was found when thyroidectomized groups were compared with controls. This increase is due to the lack of thyroxin since it can be counteracted by thyroxin administration. Whether this increased coated pit formation is a membrane retrieval mechanism or is related to the uptake of extracellular molecules remains to be determined.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 65
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 240 (1985), S. 247-249 
    ISSN: 1432-0878
    Schlagwort(e): Heart ; Mitochondria ; Perfusion ; Ultrastructure ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Mitochondria isolated from heart tissue after a 1-min perfusion with Hanks medium were found to have significantly lower rates of State-3 respiration and respiratory control ratios compared to mitochondria isolated from non-perfused hearts. Examination of the mitochondrial preparations by electron microscopy revealed that a large proportion of the mitochondria isolated from perfused heart tissue were swollen and broken compared to mitochondria from non-perfused hearts.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 240 (1985), S. 417-423 
    ISSN: 1432-0878
    Schlagwort(e): Cysteine protease ; Epidermal cells ; Antigen localization ; Cell differentiation ; Antigen distribution ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Monospecific antibody directed to cysteine protease of 2-day-old rat epidermis recently characterized as being different from the proteases previously reported was produced in rabbits. By immunofluorescence microscopy and immunoperoxidase staining with an avidin-biotin-peroxidase method the protease was found to be present in the epidermis of rodents of different ages as well as that of humans, but not in the dermis. The staining in germinative cells was more intense than in cells in the superficial layers. It appeared as irregular patches in the nuclei and stained more diffusely in the cytoplasm where small granular components, strongly stained, were identified. The staining patterns in granular cells showed accumulation of the antigen in a granular form. The morphology and distribution of granules resembled those of keratohyalin-like granules in the nucleus and dense homogenous deposits in the cytoplasm. In cornified cells the reaction product was localized by the plasma membrane where concentration of the dense homogenous deposits occurred, suggesting that the cysteine protease is one component of the unique and characteristic structure of differentiated keratinocytes. In addition, the cysteine protease antigen having the same molecular weight as the epidermal enzyme was detected in liver, kidney and lung indicating a wider tissue distribution of the protease. The significance of the protease in regulation of cellular functions remains to be investigated.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 67
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 241 (1985), S. 1-8 
    ISSN: 1432-0878
    Schlagwort(e): Pituitary gland, pars intermedia ; Reserpine ; Secretory granules ; α-MSH ; β-Endorphin ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Reserpine has a stimulatory effect on the pars intermedia of the rat pituitary, probably mediated by its action on regulatory catecholaminergic nerves. The effect of single intraperitoneal injections of 0.1–20 mg/kg b.w. of reserpine was studied in adult male rats. Reserpine at a dose of 2 mg/kg b.w. induced degranulation, orientation of the secretory granules along the cell membrane and loss of formaldehyde-chloral-induced fluorescence, accompanied by an activation of the granular endoplasmic reticulum and the Golgi apparatus. With higher doses progressive degranulation and loss of fluorescence were observed. The effect was, however, heterogeneous, and with all doses cells displaying normal ultrastructure and normal fluorescence were regularly present. To study the release of granular products (containing a different components of the pro-opiomelanocortin chain) from individual cells, formaldehyde-chloral induced fluorescence and α-MSH- and β-endorphin immunoreactivies were demonstrated in consecutive sections from pituitaries of rats given 8 mg/kg body weight of reserpine 24 h before sacrifice. The results indicate coordinated release of these granular products at the cellular level after reserpine treatment.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 68
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 240 (1985), S. 49-55 
    ISSN: 1432-0878
    Schlagwort(e): Lymph node ; Reticular cell ; Mast cell granule ; Fibronectin ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Granules released from mast cells were examined by electron microscopy in regional lymph nodes of rats after the injection of a large dose of horseradish peroxidase (HRP). Thirty minutes after the injection, a large number of mast-cell granules were present in sinuses, most of which adhered to the surfaces of reticular cells and some to macrophages. Two hours after the injection, a number of granules had been taken up by both reticular cells and macrophages. Reticular cells took up more granules than macrophages. Twenty-four hours after the injection, granules were scarce in both types of cells and in the extracellular space. Reticular cells surely participate in dealing with released mast-cell granules in the lymph node. Fibronectin bound to all mastcell granules was demonstrated by immunohistochemistry. Fibronectin probably enables negatively charged mast-cell granules to approach negatively charged cell surfaces to be taken up by both reticular cells and macrophages.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 69
    ISSN: 1432-0878
    Schlagwort(e): Macrophage activation ; Pseudomonas aeruginosa ; X-ray microanalysis ; Elemental analysis ; Electrolytes ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Electron probe X-ray microanalysis (XRMA) of freeze-dried ultrathin sections provides the capability of measuring intracellular elemental content. This methodology was used to investigate the stimulus-permeability coupling responses associated with phagocytosis of Pseudomonas aeruginosa by cultured pulmonary alveolar macrophages (PAMs) of rats. PAMs were challenged with P. aeruginosa suspended in Gey's buffer at a bacteria to PAM ratio of 50∶1 for 1 h at 37° C. A 1-mm3 pellet of the unchallenged control PAMs, challenged PAMs and P. aeruginosa alone was quench-frozen in nitrogen-cooled, liquid propane, and 0.1-μm cryosections were cut at -100° C. X-ray spectra were collected for nucleus and cytoplasm of 39 control PAMs, 36 challenged PAMs and 40 P. aeruginosa. Concentrations (mmole/kg dry weight) were obtained for Na, Cl, K, Ca, Mg, P, S for each cell. In the control PAMs, the content was similar to other mammalian cells. Moreover, there were no differences in elemental content between nucleus and cytoplasm. In the challenged PAMs, Na concentration was 4 times that of control PAMs (p〈0.001) whereas Cl was double (p〈0.001), K was 29% lower (p〈0.001), and Ca was 4 times higher (p〈0.05). The elemental concentration profile in the P. aeruginosa was distinctly different from that of the PAMs: higher Na, Ca, Mg, but lower Cl and K values. These results demonstrate elemental content changes in cultured PAMs challenged with P. aeruginosa that indicate a stimulus-permeability response by membranes associated with the phagocytic process.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 240 (1985), S. 271-276 
    ISSN: 1432-0878
    Schlagwort(e): Pituitary ; Castration ; Gonadotropes ; Mitosis ; Testosterone replacement ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The proliferation of gonadotropes in the anterior pituitary of the castrated male rat was examined immunohistochemically after colchicine treatment. The results show a more than 10-fold increase in mitotic frequency in gonadotropes 1 or 2 weeks after castration, as compared with controls. This result explains the increase in the population of immunoreactive LH cells in castrated male rats. The gonadotropes decreased significantly 1 month after castration. The mitotic activity of gonadotropes was almost completely suppressed in castrates implanted with a silastic tube filled with testosterone.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 240 (1985), S. 281-285 
    ISSN: 1432-0878
    Schlagwort(e): Cell dissociation ; Chromaffin cells ; Adrenal medulla ; Tissue transplantation ; Brain grafts ; Rat ; Marmoset monkey
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Adrenal chromaffin cells from adult rats and monkeys were mechanically dissociated and implanted into the striatum of adult rats by stereotaxic injection. Rat chromaffin cells survived (5%) and showed differentiation by forming processes 1 h-28 days after implantation. Monkey chromaffin cells survived for 48 h but showed very little formation of processes. The method presented allows rapid nonenzymatic dissociation and transplantation of adrenal medullary cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 240 (1985), S. 529-534 
    ISSN: 1432-0878
    Schlagwort(e): Collagen fibril ; Freeze-fracture ; Tail tendon ; Rat ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of the collagen of rat tail tendon was investigated by the freeze-fracture technique. Collagen fibers were pretreated with the digestive enzymes, α-amylase, elastase and collagenase to remove matrix substances. Some of the samples were etched for 20 min. Fibrils had an average diameter of 318±12 nm and a banded structure with a mean periodicity of 64.2±0.9 mm; the banding was most marked in α-amylase/elastase-treated specimens, although the periodicity was independent of pretreatment. Microfibrils were well-displayed following α-amylase/elastase and collagenase pretreatments. A difference in the diameters of microfibrils was, however, observed between etched specimens (8.3±0.3 nm) and those prepared by other experimental methods (11.4±0.5 nm). In replicas of collagenase-treated and etched specimens, the interconnecting filaments in the interfibrillar region formed a network that was continuous with the microfibrils of collagen fibrils. The diameter of the interconnecting filaments was the same as that of microfibrils. Microfibrillar bundles were observed in the interfibrillar region.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 73
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 240 (1985), S. 575-584 
    ISSN: 1432-0878
    Schlagwort(e): CRF neurons ; Neurosecretory neurons ; Hypothalamus ; Immunohistochemistry ; Colchicine ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The immunoreactive CRF-neurons of the rat hypothalamus have been examined immunohistochemically employing anti-rat CRF serum. These neurons are confined to the paraventricular nucleus, dorsomedial-lateral hypothalamic area, and suprachiasmatic nucleus, and are, respectively, also immunoreactive to anti-Met-enk, -alpha-MSH, and -VIP sera. Intraventricular administration of colchicine (50 μg/5 μl/rat) induces a dramatic enhancement of the immunostainability of the cell somata, and also accelerates the development of immunoreactivity of other stored peptides, especially in the paraventricular nucleus. The CRF-neurons respond to adrenalectomy by showing increased immunoreactivity and an increase in the number of cell bodies; in the dorsomedial-lateral area and suprachiasmatic nucleus, there is also an enhanced immunoreactivity for alpha-MSH and VIP, respectively. CRF-cells in the paraventricular nucleus become markedly hypertrophied, but do not show any enhanced immunoreactivity for Met-enk. Since the axons of the paraventricular neurons run to the median eminence, it is probable that they are involved with the endocrine control of hypophysial ACTH release. It is concluded that the CRF-containing neurons in rat hypothalamus consist of three types which are functionally and morphologically different.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 74
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 240 (1985), S. 663-667 
    ISSN: 1432-0878
    Schlagwort(e): PRL-like material ; Histoimmunology ; Testis ; Adenohypophysis ; Rat ; Mouse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Anti-rat prolactin (PRL) antibodies were localized by histoimmunological methods in the cytoplasm of testicular interstitial cells, Sertoli cells, spermatogonia and primary spermatocytes of the rat and mouse. Control of specificity by affinity chromatography methods showed this PRL-like material to be non-specific in these testicular tissues, but specific in adenohypophyseal cells. These results are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 75
    ISSN: 1432-0878
    Schlagwort(e): Kupffer cells ; Liver endothelial cells ; Cultures ; Surface receptors ; Percoll ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary This paper presents a study on the structure and function of Kupffer cells (KC) and liver endothelial cells (LEC) isolated by a simple and rapid technique involving 1) perfusion of the liver with collagenase; 2) cell separation by means of density centrifugation in Percoll; and 3) cell culture, taking advantage of the fact that KC and LEC differ in their preferences for growth substrate. The KC, which attach and spread under serum-free conditions on surfaces of glass or plastic during the first 15 min in culture exhibit a typical macrophage-like morphology including membrane ruffling and a heterogenous content of vacuoles. Moreover, these cells express (a) Fc receptors (FcR) for binding and phagocytosis of erythrocytes covered with immune globulin G (E-IgG), and (b) complement receptors (CR) for binding and serum dependent phagocytosis of erythrocytes covered with either human C3b or mouse inactivated C3b (iC3b). The cells also bind fluid phase fluoresceinated C3b. Approximately 30% of the KC express immune response-associated (Ia)-antigens. The LEC attach and spread on fibronectin coated surfaces, but not on glass or plastic surfaces, during the first two hours in culture with or without serum, and are morphologically distinct from KC. Cultured LEC are well spread out with no membrane ruffling and with numerous large vesicles surrounding the regularly shaped nucleus. These cells bind, but do not ingest E-IgG via the FcR, but no binding of fluid phase C3b or particle fixed C3b or iC3b can be observed. Incubation of LEC with fluorescein amine conjugates of ovalbumin or formaldehyde treated serum albumin, but not with fluoresceinated native serum albumin, results in accumulation of fluorescence specifically localized in the large perinuclear vesicles. Neither KC nor any other cell types tested have the ability to accumulate fluorescence upon incubation with these compounds. Iaantigens are not present on the LEC. Cytochemical demonstration of unspecific esterase, acid phosphatase, and peroxidase reveals different patterns and intensities of staining in KC as compared to LEC.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 241 (1985), S. 657-662 
    ISSN: 1432-0878
    Schlagwort(e): Epididymis ; Differentiation ; Organ culture ; Castration ; Ultrastructure ; Morphometry ; Cell types ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The differentiation capacity of the rat epididymis after depletion of androgen was studied in organ culture and in castrated rats. The differentiation of ‘narrow cells’ in 5- and 10-day-old explants and in 10-day-old castrated rats suggests that: (i) the testicular androgens are not essential for their differentiation, (ii) a differential androgen dependence exists among the epididymal cell types, (iii) the undifferentiated epithelial cells are the precursors of the narrow cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 241 (1985), S. 671-675 
    ISSN: 1432-0878
    Schlagwort(e): Collagenase ; Osteoclast ; Bone resorption ; Osteoblast ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The cell-free endocranial surface of young adult rat parietal bones was used as a substrate for bone cell-derived mammalian collagenase. Incubation of parietal bones in a concentration of enzyme comparable to that secreted by osteoblastic cells in vitro caused destruction of surface osteoid, and resulted in exposure of mineral onto the bone surface. Bones so pre-treated were considerably more susceptible to osteoclastic resorption than bones preincubated in the absence of collagenase. These results are consistent with the view that the osteoid layer which covers bone surfaces acts as a barrier to osteoclastic contact with underlying, resorption — stimulating bone mineral; and that cells of the osteoblastic lineage induce osteoclastic resorption through collagenase secretion which, by digestion of the surface osteoid, exposes bone mineral to osteoclastic contact.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 241 (1985), S. 445-451 
    ISSN: 1432-0878
    Schlagwort(e): Bed nucleus of the stria terminalis (NIST) ; Blood supply ; Double-ink perfusion ; Arteries ; Veins ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The topographical distribution of the blood vessels in the bed nucleus of the stria terminalis (NIST) has been mapped in rats. Arteries and veins were visualized in red and blue by using a double-ink perfusion technique. Arteries supplying the NIST arise from the anterior cerebral artery directly or through the anterior communicating and interhemispheric arteries. Only a few, dorsal branches derive from the medial cerebral artery through thalamostriatal arteries. According to their terminal branches, NIST arteries can be divided into five groups: medial, ventral, lateral, septal and dorsal, which have only a relatively small overlap in their territories. About 90% of veins from the NIST drain into the major basal veins. Medial branches run into the perioptic and interhemispheric veins, while the ventral branches and the large lateral vein drain directly into the anterior cerebral vein. A small proportion of NIST veins run dorsalward into the vena cerebri magna via thalamostriatal veins.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 241 (1985), S. 459-463 
    ISSN: 1432-0878
    Schlagwort(e): Myocardium ; Regeneration ; Ultrastructure ; Cold injury ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The sequential cytological events in the myocardium of the rat were followed for 3 weeks after cold injury by light and electron microscopy. The traumatized area was initially filled with leukocytes and undifferentiated mononucleated cells and subsequently mainly with fibroblasts surrounded by collagen fibers. However, in the margins of the necrotic area repair processes of damaged myocardial cells and probably also the appearance of newly formed cells were evident. The ultrastructural features of these cells were characterized by clusters of ribosomes, numerous mitochondria that were dispersed in the cytoplasm and formation of junctional complexes and transverse tubular systems. Fibrillogenesis was also clearly evident in these cardiomyocytes. The myofibrillar material was initially dispersed in the cytoplasm and associated with clusters of ribosomes and thereafter with presumptive Z-bands and intercalated discs. The myofibrils became further organized in the shape and orientation of those of mature cells two to three weeks after injury. It is concluded that following cold injury regeneration in the mammalian myocardium takes place but is limited to the perinecrotic area. The process resembles the sequential cytological events which occur in cardiomyocytes during embryonic and postnatal development of the ventricular myocardium.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 80
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 241 (1985), S. 465-472 
    ISSN: 1432-0878
    Schlagwort(e): Striated muscle ; Muscle fiber type ; Schwann cells ; Motor endplate ; Scanning electron microscopy ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The three-dimensional organization of the motor end plates in the red, white and intermediate striated muscle fibers of the rat intercostal muscle was observed under a field-emission type scanning electron microscope after removal of connective tissue components by HCl hydrolysis. The motor endplate of the white fiber had terminal branches (or axon terminals), which were large, long and thin, and small but numerous nerve swellings (or terminal boutons). The motor endplate of the red fiber had terminal branches, which were small, short and thick, and had large but fewer nerve swellings. The motor endplate of the intermediate fiber was intermediate in size and structure between these two. In detached nerve-ending preparations, primary synaptic grooves with slit-like openings of the junctional folds appeared on the surface of the muscle fibers. The primary synaptic grooves were more developed in the white fiber than in the red fiber, and they were intermediate in the intermediate fiber. The numerical ratio of slit-like openings was 1∶1.8∶3.5 in the red, intermediate and white fiber, respectively. The Schwann cells and their processes were observed on the surface of the motor endplate, with the processes covering the upper orifices of the primary synaptic grooves and sealing the terminal branches. The number of Schwann cells was usually three in the white fiber, two in the intermediate fiber and one in the red fiber.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 81
    ISSN: 1432-0878
    Schlagwort(e): Noradrenaline- and adrenaline-storing cells ; Noradrenaline ; Adrenaline ; Adrenal medulla ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The pre- and postnatal development of the adrenal medulla was examined in the rat by immunohistochemistry and by assay of catecholamines. Immunohistochemistry involved the use of antibodies to noradrenaline (NA), adrenaline (A) and the biosynthesizing enzymes dopamine β-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT). Adrenal glands were obtained from animals from the 16th day of gestation to the 7th postnatal day at daily intervals, and at the 14th postnatal day, and from adult rats. Tissues were fixed in ice-cold, 4% paraformaldehyde, buffered at pH 7.3. Cryostat sections (7 μm) were stained with the indirect immunofluorescence technique. Adrenals from the same developmental stages were assayed for the presence of DA (dopamine), NA and A by ion-pair reversed-phase liquid chromatography with electrochemical detection. In adult adrenals the majority of the medullary cells (approximately 80%) were highly immunoreactive to A and moderately immunoreactive to NA. They also showed immunoreactivity to both DBH and PNMT, i.e., they are synthesizing and storing A. The remaining cell clusters were only stained by antibodies to DBH and NA (NA-synthesizing and -storing cells). These findings correlate well with the relative concentrations of A and NA as determined by assay. Three developmental phases could be distinguished. In the first phase, the 16th and 17th prenatal day, medullary cells were only immunoreactive to DBH and NA, and only very small amounts of A as compared to NA were found. During the second period, from the 18th prenatal day to 2 or 3 days after birth, all medullary cells were immunoreactive to DBH, NA, PNMT and A, and during this phase the adrenaline concentration increased daily and became the predominant amine on the 20th day of gestation. Adrenaline represented 75% of total catecholamine on the 1st to 3rd day after birth. The third phase started at the 2nd or 3rd postnatal day and was characterized by the presence of an increasing number of medullary cells solely immunoreactive to DBH and NA, hence synthesizing and storing NA. The remaining cells were immunoreactive to DBH, NA, PNMT and A. Postnatally, the relative concentration of A continued to rise reaching 79% by the 4th postnatal day. These results indicate that initially the adrenal medullary cells are synthesizing and storing almost exclusively NA. Probably, adrenaline synthesis begins at the 16th–17th day of gestation and the cells are then capable of synthesizing and storing both NA and A (“mixed cell type”) with A synthesis and storage rapidly becoming predominant. Finally, after birth, separate NA-synthesizing and -storing cell types are formed and the so-called A cells stored predominantly (probably 〉90%) adrenaline with a small proportion of noradrenaline. In the medullary blastema and in the sympathetic ganglia of prenatal animals two cell types, only immunoreactive to DBH and NA, were observed. Presumably, these cells represent developing sympathetic neurons and extra-adrenal chromaffin cells; the latter cell type occasionally invades the adrenal gland. Thus, prospective medullary cells are able to synthesize and store NA before they have made contact with the cortical blastema but A-synthesizing cells are found only within the adrenal gland. Low but significant amounts of DA were found in the adrenal before birth and during the first two postnatal weeks but in the adult animal this accounted for less than 0.1% of total catecholamine.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 242 (1985), S. 391-398 
    ISSN: 1432-0878
    Schlagwort(e): Development, ontogenetic ; Lymph nodes ; Non-lymphoid cells ; Lymphocytes ; Immunohistochemistry ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The postnatal development of the various cell populations in the rat popliteal lymph node was investigated applying enzyme-histochemical and immunohistochemical techniques. From birth, T-lymphocytes and interdigitating cells were demonstrable. During the development of the young lymph node, T-lymphocytes of the helper phenotype outnumbered the T-cells with a suppressor phenotype; they account for approximately 70% and 30% of all T-lymphocytes, respectively. At the very first day of postnatal life, post-capillary venules were already present. B-lymphocytes occurred later than T-cells during ontogeny; they were found on the second day after birth, most of them being IgM- or IgG-bearing lymphocytes. The first primary follicles occurred at day 18 and contained principally membrane-stained IgM cells and, to a lesser extent, membrane-stained IgG cells. The appearance of follicular dendritic cells correlated with the formation of primary follicles. With respect to the macrophages, it appeared that the ED1- and ED3-positive subpopulations were present with a similar distributional pattern as seen in adults, but in considerably lower numbers. The expression of ED2, however, showed a sudden increase in the third week of life. Findings of the present study are discussed in relation to those obtained in other investigations dealing with the ontogenetic development of lymphoid organs.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 83
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 242 (1985), S. 505-510 
    ISSN: 1432-0878
    Schlagwort(e): Hyaluronic acid uptake ; Liver ; Liver endothelial cells ; Kupffer cells ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The uptake of [3H]acetyl-labelled hyaluronic acid (HA) Abbreviations used in this paper: HA hyaluronic acid; i.v. intravenous was examined in the liver, spleen and kidney of the rat after i.v. injection. 3H-activity was located by light- and electron-microscopic autoradiography after measurement by scintillation counting of tissue digests. In the liver, approximately 90% of the radioactivity was located in the sinusoidal endothelial cells, with autoradiographic grains distributed throughout the cytoplasm; 50% of the grains overlay vacuoles 0.3 to 1.2 μm in diameter. A few grains (4%) were located in Disse's space or nearby in the cytoplasm of hepatocytes. No grains were found in Kupffer cells. The remainder were randomly scattered across the sections in a pattern indicating nonspecific background activity. These observations are in accordance with the selective uptake of HA exhibited by dissociated liver cells in vitro. HA concentrations in the spleen and kidney were too low for detection by autoradiography. Splenic concentrations were much lower than in rabbits or mice; in this respect the uptake of circulating HA in the rat resembles that reported for chondroitin 4-sulphate.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 84
    ISSN: 1432-0878
    Schlagwort(e): Exocrine pancreas ; Rat ; Cortisone ; Ultrastructure ; Enzyme secretion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary We have investigated the short-term effects of hydrocortisone (60 mg/kg per day) and placebo on basal and stimulated pancreatic secretion in the conscious rat. Volume and enzyme secretion were determined; fine structural changes were examined simultaneously. The pancreatic and bile ducts were cannulated separately; pancreatic juice was drained via an isolated fistula, and bile was recirculated into the duodenum. The application of hydrocortisone led to an almost complete inhibition of the secretory response of the exocrine pancreas when stimulated with 0.25 U secretin in combination with 5 × 10-8 g caerulein per h. It strongly affected the secretion rates of volume, protein, lipase, chymotrypsin, trypsin and carboxypeptidase, whereas the secretion rate of alpha-amylase continued to show a slight increase after stimulation. After stimulation with secretin and caerulein, the hydrocortisone-treated animals showed a higher density of zymogen granules in the acinar cell and an increase in the number of autophagic vacuoles in comparison to the equally stimulated placebo-treated rats. It is concluded that the short-term inhibition of pancreatic secretion by hydrocortisone occurs largely as a result of an inhibition of cellular enzyme discharge.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 242 (1985), S. 457-460 
    ISSN: 1432-0878
    Schlagwort(e): Thyroid gland ; Innervation ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Axon profiles in thyroid glands obtained from adult male Wistar rats were studied electron-microscopically, using common and serial thin sections. Bouton profiles of nerve fibers, resembling the terminal or en passant type, often appeared closely associated with vascular smooth muscle cells via basement membranes. These structures are probably adrenergic, since they contained mainly small-core vesicles (mean diameter: 41.2 nm), in addition to a few large-core (mean diameter: 88.4 nm) and flattened vesicles. Nerve fibers containing microtubules and sometimes mitochondria and vesicles were seen lying between basement membranes and follicular cells. The incidence of nerve fiber contacts on profiles of follicular cells was 0.0177±0.0092 (S.D.). Using serial sections, follicles were seen to have up to two nerve endings, separated from the plasma membranes of the follicular cells by a gap of 22 nm. They contained mainly flattened vesicles and several large-core vesicles (mean diameter: 95.1 nm). Small-core vesicles were rarely seen in these nerve endings. Furthermore, subsurface cistern-like rough endoplasmic reticulum was found immediately under the plasma membranes of follicular cells facing membranes of nerve endings. These results suggest that the nerve fibers in contact with follicular cells are different from the adrenergic type.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 86
    ISSN: 1432-0878
    Schlagwort(e): Lymph node ; Antigen stimulation ; Dendritic cells ; Enzyme- and immunocytochemistry ; Ultrastructure ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Non-lymphoid dendritic cells were isolated from normal and paratyphoid vaccine-stimulated lymph nodes draining the rat skin. They were studied using enzymecytochemical, immunocytochemical and electron-microscopical methods. These cells had an irregular outline and an eccentrically situated nucleus. All showed acid phosphatase activity in a central area and expressed Ia antigen on the plasma membrane. Birbeck granules were exclusively present in dendritic cells isolated from lymph nodes in the induction phase of the immune response. This observation concurs with the presence of Birbeck granules in interdigitating cells in situ during the same period of the immune response. It is concluded that the dendritic cells are the in-vitro equivalents of the non-actively phagocytizing population of interdigitating cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 87
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 295 (1999), S. 55-64 
    ISSN: 1432-0878
    Schlagwort(e): Key words Axonal transport ; Purkinje cell ; Organotypic culture ; Microinjection ; Antimitotic drugs ; Cytoskeleton ; Dendritic transport ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Axonal and dendritic transport in single Purkinje neurons of cerebellar slice cultures was quantified as single transport distances. Examination of the cells within a vital tissue was regarded as being an approach to the in situ condition. The Purkinje cells were organotypically integrated in the in vitro tissues and extended long axonal projections connecting synapses to the target neurons. The tracer horseradish peroxidase (HRP) was applied via microinjection to the somata of the Purkinje cells and the injected neurons were incubated thereafter for defined time-intervals. The tracer was transported anterogradely into the neuron processes. The measurements on both the axonal and the dendritic transport of microinjected HRP revealed continuous transportation with increasing times of postincubation. This transport was reduced by the use of microtubule-depolymerizing drugs. The axonal transport of the tracer was either retarded in colchicine-treated cells or continuously reduced for up to 50% in vinblastine-treated neurons. Thus, a correlation of axonal transport to the microtubules was demonstrated. The dendrites were filled with the tracer after 60 min of postincubation. Dendritic transport was reduced by the use of vinblastine, and not significantly by colchicine. The results strongly support the dependence of neuronal transport on microtubules as a component of the cytoskeleton.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 240 (1985), S. 585-591 
    ISSN: 1432-0878
    Schlagwort(e): Parathyroid gland ; Ageing ; Secretory cycle ; Morphometry ; Fixation ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Parathyroid glands of newborn to 1-year-old male Sprague-Dawley rats were fixed by perfusion or by immersion, and prepared for electron microscopy. Parathyroid glands fixed by immersion exhibited parenchymal cells with variable ultrastructure, indicating that these cells were in different stages of the proposed secretory cycle in parathyroid cells. In contrast, parathyroid cells of glands fixed by perfusion were uniform in ultrastructure, suggesting that all cells were in the same stage of secretory activity. Parathyroid glands of 3-, 4-, 6-, 8- and 10-week-old rats also were fixed by perfusion and analysed by electron-microscopic morphometry. These data demonstrated an increase in cell volume and in surface area of the membrane compartments concerned with parathyroid hormone secretion: these changes were not related to variations in serum calcium concentration. Both the qualitative observations and the quantitative data do not favour the idea of a secretory cycle in rat parathyroid cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 89
    ISSN: 1432-0878
    Schlagwort(e): Parathyroid ; Storage granule ; Hypercalcemia ; Immunocytochemistry ; Acid phosphatase ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Short-term effects of CaCl2-treatment on parathyroid cells of the rat, especially on their storage granules, were studied at the ultrastructural level. After an injection of 4% CaCl2, serum calcium levels (SCL) rapidly increased from 9.1 mg/dl (controls) to a maximum of 14.9 mg/dl at 20 min. At 5 min after the injection, the number of type-I storage granules (large core) [NSG-I] and that of type-II storage granules (small core) [NSG-II] remained unchanged, in spite of elevated SCL (12.4 mg/dl). As soon as SCL rose to 13.2 mg/dl at 7.5 min, NSG-I gradually decreased to a minimum at 30 min; in contrast, NSG-II gradually increased to a maximum at 30 min. Vacuolar bodies also increased together with the augmentation of type-II storage granules. The average diameter of the core of the storage granules decreased significantly after the injection. Protein A-gold method for immunocytochemistry showed that the cores of these granules contain parathormone. Acid-phosphatase activity was occasionally found in storage granules of both types, especially in those of type II. It is concluded (i) that type-I storage granules may be transformed into vacuolar bodies via type-II granules as a result of hydrolysis, and (ii) that these processes may be accelerated during hypercalcemia.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 241 (1985), S. 183-192 
    ISSN: 1432-0878
    Schlagwort(e): Postnatal development ; Oxidative metabolism ; Enzyme histochemistry ; Fiber type ; Muscle, striated, skeletal ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The postnatal development, between 0 and 90 days, of three hindlimb muscles and diaphragm of the rat was investigated with respect to fiber types and diameter (histochemistry) and substrate oxidation rates and enzyme activities (biochemistry). The process of muscle fiber differentiation into mature patterns was evaluated by visual classification into 3 or 4 groups having different staining intensities for 3 enzyme-histochemical reactions, enabling 26 fiber types to be distinguished. These exhibited specific sizes and growth rates that varied among the muscles. One of the hindleg muscles (flexor digitorum brevis) remained much more immature than soleus and extensor digitorum longus. The histochemical and biochemical findings correlated well. The capacity for pyruvate and palmitate oxidation, and the activities of cytochrome c oxidase and citrate synthase, increased markedly between 9 and 37 days in soleus and extensor digitorum longus (except citrate synthase in the latter) but not in flexor digitorum brevis. Creatine kinase activity increased in all hindlimb muscles. Both the capacity and the activity of pyruvate oxidation (determined in homogenates and intact isolated muscles, respectively), were in accordance with the fiber type composition. In contrast to oxidation capacity, the activity of pyruvate oxidation decreased after birth until the mature stage, when a value of 18–42% of that of early postnatal muscles was recorded.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 91
    ISSN: 1432-0878
    Schlagwort(e): Secretory granules ; Salivary glands ; Secretion ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A method is described for the isolation of two populations of secretory granules from rat parotid glands utilizing differences in their sedimentation characteristics. The granule preparations were analyzed for homogeneity by electron microscopy and chemical analyses. The soluble contents of both types of granules were obtained by hypotonic lysis, and the proteins compared by SDS-PAGE and ion exchange-gel filtration chromatography. Both populations of secretory granules appear to have the same protein composition as that of the parotid saliva. The secretory granules with the smaller apparent buoyant density became labelled with radioactive leucine earlier than the heavier granules when a pulse of this amino acid was supplied to a gland slice system. The lighter granules appear to represent an earlier stage in maturation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 92
    ISSN: 1432-0878
    Schlagwort(e): CRF immunohistology ; Paraventricular nuclei ; Pituitary gland, pars nervosa ; Electron microscopy ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A fine network of corticotropin-releasing factor (CRF)-immunopositive fibers was found in the posterior lobe of the pituitary of the rat. The intermediate and distal lobes were free of CRF-immunoreactivity. Varicose, terminal-like axons were frequently observed around capillary vessels. Surgical isolation of the paraventricular nuclei resulted in a complete disappearance of CRF-immunoreactive fibers from the posterior lobe. CRF-immunopositive fibers show the general characteristics of peptidergic axons. These ultrastructural observations support the idea that CRF is secreted into capillary vessels.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 93
    ISSN: 1432-0878
    Schlagwort(e): Corticotropin-releasing factor (CRF) ; Mammillary body ; Immunohistology ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The presence and distribution of CRF-immunoreactive cells and nerve fibers were studied in the mammillary body of the rat, 12 days after placing various types of lesions within the hypothalamus. Anterior and anteriolateral cuts, placed in the midhypothalamus immediately behind the paraventricular nuclei resulted in an almost complete disappearance of CRF-immunoreactive fibers from the median eminence and simultaneous appearance of CRF-containing neurons in the mammillary body. Posterior or postero-lateral hypothalamic cuts carried out in front of the mammillary body caused the accumulation of CRF-immunoreactive material in neurons and neural processes located behind the cut-line. This type of intervention had no effect on the quantity of CRF fibers in the median eminence. A cut running through the central part of the mammillary body in the frontal plane resulted in appearance of CRF neurons only in the posterior half of the mammillary region. Placing a cut behind and over the mammillary body, CRF-immunoreactive neurons became detectable below the superior cut-line. No immunoreactive neurons were observed in the mammillary body when the frontal cut reached the base of the brain at the posterior border of the nucleus, leaving intact its anterior and superior connections. In all these cases when the mammillo-thalamic tract was transected, CRF neurons became detectable in the mammillary body.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 94
    ISSN: 1432-0878
    Schlagwort(e): Thymus ; Non-lymphoid cells ; Cell contacts ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary This study attempted to define reciprocal positions of cell types within the thymus. Random or non-random contacts between specific cell types were analyzed by means of graph theory. For analysis, thymus blocks were sectioned serially and, then, thymus cells were categorized into types, based on morphological criteria. The distribution of individual cell types within the cortex, cortico-medullary zone and medulla was presented in form of a map. In the analysis, three types of epithelial cell, characteristic of each thymus zone, macrophages, Langerhans-like cells and lymphocytes were found in non-random relations to one another. Moreover, characteristic groups of cells associated with one another were also demonstrated.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 240 (1985), S. 485-487 
    ISSN: 1432-0878
    Schlagwort(e): Oxytocin ; Vasopressin ; Neuropeptide ; Testis ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The presence of oxytocin, vasopressin and neurophysin in the testis of adult Wistar and Brattleboro rats has been examined immunocytochemically. After fixation in modified Bouin's solution, or Bouin's sublimate fixative, immunostaining was accomplished with the peroxidase-antiperoxidase method. The presence of immunoreactive oxytocin was demonstrated in 80% of the interstitial cell population of both rat strains while no staining was observed for vasopressin or neurophysin.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 96
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 240 (1985), S. 493-496 
    ISSN: 1432-0878
    Schlagwort(e): Calcium-binding protein (CaBP) ; Horizontal cells ; Retina ; Vitamin D ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Horizontal cells of rat retina were labeled intensely by a specific antibody to cerebellar calcium-binding protein. The amacrine cells stained very weakly. The presence of calcium-binding protein in horizontal cells could be of interest for the understanding of the feedback action of these cells on photoreceptors.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 240 (1985), S. 277-280 
    ISSN: 1432-0878
    Schlagwort(e): Adrenal vasculature ; Portal system ; Microspheres ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The intra-glandular vascular arrangement in the adrenal has been studied using non-radioactive microspheres injected by three different routes: in-vivo injection into the left ventricle under pentobarbital anesthesia, postmortem orthograde, and postmortem retrograde injection. The doses of microspheres were 105 (average size 24.7 μm), 106 (15.8 μm) and 107 (9.9 μm). The entrapment rate of microspheres by the medulla as compared with the whole gland was measured in the serially sectioned tissue (section thickness 60 μm). The entrapment rates of 25-μm microspheres differed between the orthograde and retrograde injections, while the entrapment rates for 15-μm microspheres were essentially similar irrespective of the route of injection. Our results support the conclusion from previous microangiographic studies that the adrenal cortex and medulla are supplied by different arteries but have a common venous outflow, and that direct communication between cortical and medullary sinusoids is not likely. The medullary blood flow per gram tissue weight is estimated to be larger than cortical blood flow.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 241 (1985), S. 581-584 
    ISSN: 1432-0878
    Schlagwort(e): Pituicytes ; GABA ; Electron-microscopic autoradiography ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Distribution of (3H)GABA in the rat neural lobe was investigated 5 min after intracarotid administration using quantitative electron-microscopic autoradiography. Specificity of (3H)GABA-uptake was tested by pretreatment of control animals with nipecotic acid. It was concluded that, apart from a small fraction in the perivascular spaces, radioactivity was present exclusively in pituicytes. The results confirm and quantify earlier in-vitro observations; they are compared with recent immunocytochemical findings that reveal the presence of glutamate-decarboxylase-containing axons in the neural lobe. It is concluded that there may be GABAergic terminals that lack an uptake mechanism for exogenous transmitter. Nevertheless, (3H)GABA autoradiography is useful in demonstrating other functional components of GABAergic systems, i.e., glial cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 242 (1985), S. 57-66 
    ISSN: 1432-0878
    Schlagwort(e): Lamina propria ; Intestinal mucosa ; Reticular tissue ; Scanning electron microscopy ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The three-dimensional architecture of the lamina propria in the jejunal mucosa of the rat was studied by scanning electron microscopy. The lamina propria is a typical reticular tissue with fine nets of reticular fibers and free and fixed cells lying among them. However, the lamina propria in the core of villi displayed structural features closer to other reticular or lymphoid tissues than that among the crypts. In the villi, the tissue was supported by a spongy framework of interconnecting fibroblasts, and densely infiltrated by free cells. Among the crypts, cellular elements were rather sparsely dispersed in a complex network of reticular fibers. A thin layer of reticular fibers lined the basal lamina of the epithelium. This layer contained a network of flattened cells which anastomosed with each other via slender processes. The basal lamina and the fibrous layer were perforated with round pores, through which free cells or basal processes of the epithelial cells passed. Many macrophages were found resting on the reticular framework of the lamina propria, frequently in close association with immunoblast-like cells. This paper further includes scanning electron-microscopic observations on the central lacteal with special reference to its luminal projections and trabeculae.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 241 (1985), S. 677-681 
    ISSN: 1432-0878
    Schlagwort(e): Autophagosome formation ; Pinealocytes ; Acid phosphatase ; Lysosome wrapping mechanism ; Rat ; Mongolian gerbil
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Autophagosome formation in rat and gerbil pinealocytes is described. It starts with the setting up of a tubular acid phosphatase-rich cisterna which gradually wraps around cytoplasmic areas to be catabolized. In light of obtained findings, it seems that the autophagosome formation in pinealocytes is a type of lysosome wrapping mechanism.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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