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31.
Ulf Dittmer Wolfgang Lüke Christiane Stahl-Hennig Cheick Coulibaly Harald Petry Walter Bodemer Gerhard Hunsmann Gerald Voss 《Journal of medical primatology》1994,23(5):298-303
Both naive and vaccinated macaques acquired a virus-specific proliferative helper T-cell reactivity in response to infection with the nonpathogenic human immunodeficiency virus type 2 (HIV-2). In contrast, macaques infected with the pathogenic simian immunodeficiency virus of the macaque strain (SIVmac) did not develop a helper T-cell response. Furthermore, a vaccine-induced preexisting T-cell reactivity was abrogated after SIVmac infection in vaccine failures. These differences may reflect the different pathogenicity of the two closely related viruses. 相似文献
32.
Frank T. Röder Thomas Schmülling Christiane Gatz 《Molecular & general genetics : MGG》1994,243(1):32-38
We have investigated the use of the tetracycline-dependent gene expression system to regenerate and propagate tobacco plants transformed with a gene whose product — when highly expressed — interferes with regeneration and/or further reproduction. Plants transformed with the Agrobacterium rhizogenes rolB gene under the control of the tetracycline-dependent expression system were phenotypically indistinguishable from wild type owing to efficient repression of the promoter. Induction of the rolB gene with tetracycline led to high-level expression of the rolB mRNA, which resulted in extremely stunted plants with necrotic and wrinkled leaves that did not develop a floral meristem. Upon cessation of tetracycline treatment healthy shoots developed even from severely affected meristems. Data on the dose response of the rolB phenotype as a function of tetracycline concentration demonstrate that the tetracycline-dependent gene expression system can be used to modulate the manifestation of a particular phenotype. 相似文献
33.
A. El-Kharbotly C. Leonards-Schippers D. J. Huigen E. Jacobsen A. Pereira W. J. Stiekema F. Salamini C. Gebhardt 《Molecular & general genetics : MGG》1994,242(6):749-754
Phytophthora infestans (Mont.) de Bary is the most important fungal pathogen of the potato (Solanum tuberosum). The introduction of major genes for resistance from the wild species S. demissum into potato cultivars is the earliest example of breeding for resistance using wild germplasm in this crop. Eleven resistance alleles (R genes) are known, differing in the recognition of corresponding avirulence alleles of the fungus. The number of R loci, their positions on the genetic map and the allelic relationships between different R variants are not known, except that the R1 locus has been mapped to potato chromosome V The objective of this work was the further genetic analysis of different R alleles in potato. Tetraploid potato cultivars carrying R alleles were reduced to the diploid level by inducing haploid parthenogenetic development of 2n female gametes. Of the 157 isolated primary dihaploids, 7 set seeds and carried the resistance alleles R1, R3 and R10 either individually or in combinations. Independent segregation of the dominant R1 and R3 alleles was demonstrated in two F1 populations of crosses among a dihaploid clone carrying R1 plus R3 and susceptible pollinators. Distorted segregation in favour of susceptibility was found for the R3 allele in 15 of 18 F1 populations analysed, whereas the RI allele segregated with a 1:1 ratio as expected in five F1 populations. The mode of inheritance of the R10 allele could not be deduced as only very few F1 hybrids bearing R10 were obtained. Linkage analysis in two F1 populations between R1, R3 and RFLP markers of known position on the potato RFLP maps confirmed the position of the R1 locus on chromosome V and localized the second locus, R3, to a distal position on chromdsome XI. 相似文献
34.
35.
Sieghart Sopper Susanne Hemm Jürgen Meixensberger Cheik Coulibaly Christiane Stahl-Hennig Gerhard Hunsmann Bernhard Fleckenstein Volker ter Meulen Rüdiger Drries 《Journal of medical primatology》1993,22(2-3):138-146
Paired sera and CSF samples were collected from SIVmac-infected macaques. Animals infected with SIVmac251 maintained low gag and high env-specific antibody levels in plasma. Increasing env-specific antibody titers in CSF were associated in one animal with strong intrathecal synthesis. SIVmac239-infected monkeys revealed high antibody titers of gag and env-specificity, in one animal accompanied by weak intrathecal synthesis of virus-specific antibodies. In all animals, the CD4/CD8 ratio in CSF decreased faster compared to blood. 相似文献
36.
37.
A. El-Kharbotly C. Leonards-Schippers D. J. Huigen E. Jacobsen A. Pereira W. J. Stiekema F. Salamini C. Gebhardt 《Molecular genetics and genomics : MGG》1994,242(6):749-754
Phytophthora infestans (Mont.) de Bary is the most important fungal pathogen of the potato (Solanum tuberosum). The introduction of major genes for resistance from the wild species S. demissum into potato cultivars is the earliest example of breeding for resistance using wild germplasm in this crop. Eleven resistance alleles (R genes) are known, differing in the recognition of corresponding avirulence alleles of the fungus. The number of R loci, their positions on the genetic map and the allelic relationships between different R variants are not known, except that the R1 locus has been mapped to potato chromosome V The objective of this work was the further genetic analysis of different R alleles in potato. Tetraploid potato cultivars carrying R alleles were reduced to the diploid level by inducing haploid parthenogenetic development of 2n female gametes. Of the 157 isolated primary dihaploids, 7 set seeds and carried the resistance alleles R1, R3 and R10 either individually or in combinations. Independent segregation of the dominant R1 and R3 alleles was demonstrated in two F1 populations of crosses among a dihaploid clone carrying R1 plus R3 and susceptible pollinators. Distorted segregation in favour of susceptibility was found for the R3 allele in 15 of 18 F1 populations analysed, whereas the RI allele segregated with a 1:1 ratio as expected in five F1 populations. The mode of inheritance of the R10 allele could not be deduced as only very few F1 hybrids bearing R10 were obtained. Linkage analysis in two F1 populations between R1, R3 and RFLP markers of known position on the potato RFLP maps confirmed the position of the R1 locus on chromosome V and localized the second locus, R3, to a distal position on chromdsome XI. 相似文献
38.
Catherine Jumarie Christiane Malo 《In vitro cellular & developmental biology. Animal》1994,30(11):753-760
Summary Caco-2 cell human colon adenocarcinoma cell line was used to study the hormonal regulation of small intestinal epithelial
cell differentiation. We had previously shown that insulin-transferrin-selenium and triiodothyronine (5 × 10−8
M)-supplemented medium can best replace serum after 2 days of culture for both the maintenance and differentiation of Caco-2
cells. The present study demonstrates that precoating petri dishes with complete serum allows the growth and differentiation
of Caco-2 cells seeded directly in serum-free medium. On the other hand, precoating with dialyzed serum inhibits alkaline
phosphatase and dipeptidyl-dipeptidase IV activities by more than 50%. The results obtained with complete serum-precoated
culture plates indicate that there is no synergy between insulin and triiodothyronine because cells maintained in transferrin-selenium
and triiodothyronine-supplemented medium, with or without insulin, express comparable enzyme activities. Moreover, large increases
in alkaline phosphatase and dipeptidyl-dipeptidase IV activities were observed when triiodothyronine was added to the culture
medium by the time confluency was reached. In contrast, γ-glutamyltransferase was lowered to a greater extent when triiodothyronine
was present from the beginning of culture. These findings show that triiodothyronine preferentially stimulates alkaline phosphatase
and dipeptidyl-dipeptidase IV activities during the differentiation period whereas it selectively inhibits γ-glutamyltransferase
during the proliferation phase. Triiodothyronine acts in a dose-dependent manner. 相似文献
39.
Bernd-Ulrich Meyburg Wolfgang Scheller und Christiane Meyburg 《Journal of Ornithology》1993,134(2):173-179
Zusammenfassung 1992 konnte ein Schreiadler mit Hilfe der Satelliten-Telemetrie nach dem Abzug aus dem Brutgebiet in Mecklenburg-Vorpommern 2125 km weit verfolgt werden. Die Ortung erfolgte durch das AGROS-System. Der Abzug erfolgte am 16. oder 17. August in SE-Richtung. Nach 660 km Luftlinie in den polnisch-slowakischen West-Beskiden schwenkte der Vogel nach Süden ab und flog fast geradlinig zwischen dem 19 ° und 22 ° E weite auf dem kürzesten Weg in Richtung Nordafrika, bis er nach 1340 km am 29. September im äußersten Südwesten des Peloponnes eintraf. Dort zögerte er, seinen Zug fortzusetzen und flog mindestens 12 Tage in nördlicher und südlicher Richtung an der Westküste hin und her. Das plötzliche Ausbleiben von Signalen nach dem 8. Oktober bei bestem Ladezustand der Batterien wird dahingehend gedeutet, daß der Adler abgeschossen wurde oder bei dem Versuch, das Mittelmeer zu überqueren, umkam.
Satellite tracking of a juvenile Lesser Spotted Eagle (Aquila pomarina) during autumn migration
Summary In 1992, for the first time a Lesser Spotted Eagle was tracked with a satellite transmitter (PTT) for 2,125 km on its migration route from its birthplace in Mecklenburg-Vorpommern (Northern Germany). Locations were obtained by the ARGOS system. The migration began on 16 or 17 August in a south-easterly direction. After 660 km the young eagle veered south in the Beskidy mountains on the Polish-Slovak border (about 80 km south of Katowice) and flew in an almost straight line between 19 ° and 22 ° E on the shortest route to North Africa (not towards the Bosphorus) until after covering another 1,340 km it reached the extreme south-west of the Peloponnese (Greece) on 24 September. There it lingered for at least 12 days flying north and south, up and down the west coast before probably continuing on its migration. The abrupt cessation of signals after 8 October, notwithstanding the prime condition of the batteries, indicated that the eagle had been shot or perished in an attempt to cross the Mediterranean.相似文献
40.