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991.
Karl-Heinz Loske 《Journal of Ornithology》1982,123(1):106
Summary Swallows(Hirundo rustica) are worth to be highly faithful to their breeding sites. Resettlements of adult swallows are described and it is concluded that calculating mortality rates by the recatching quotas may be problematic. 相似文献
992.
Zusammenfassung In der Umgebung von Schlüchtern (50.21 N, 09.31 E) führten wir von 1972/73 bis 1981/82 außerhalb der Fortpflanzungszeit regelmäßige Japannetzfänge an Futterstellen durch. Die Größe der dabei erfaßten Kohlmeisenpopulation war von der Zahl der durchgeführten Fänge abhängig. Die Zuwanderung unberingter Vögel fand über die gesamte Fangperiode statt. Die Bestandsfluktuation innerhalb einer Saison war ausgesprochen stark. Bei Ganztagesfängen nahm die Zahl erfaßter Individuen im Tagesverlauf rasch ab. In der an Futterstellen erfaßten Population hatten Zuwanderer den weitaus größten Anteil. Brutvögel und ortstreue Jungvögel aus den umliegenden Untersuchungsgebieten waren nur schwach vertreten. Zur weitgehend vollständigen Erfassung einer Japannetzpopulation sind tägliche Fänge erforderlich. Als ausreichend erwies sich im allgemeinen eine Zeit von zwei Stunden. In welcher Weise Japannetzfänge bei Kohlmeisen zur Klärung populationsdynamischer Fragen beitragen können, wird diskutiert.
Mist-netting at bird-feeders — a convenient method to study Great Tit populations?
Summary From 1972/73 to 1981/82 we mist-netted Great Tits at 25 bird-feeders near Schlüchtern (50.21 N, 09.31 E). In all years there was a strong positive correlation between number of birds registered and number of mist-nettings within a year. The number of immigrants did not decrease from August to March. There were strong fluctuations in numbers throughout the season. Mistnetting from dawn to dusk showed that more than half the individuals were captured within the first two hours. In Great Tits captured at bird-feeders immigrants outnumbered residents by far. Because of the strong fluctuations and the short stay at feeders Great Tits should be mist-netted every day. Two hours of mist-netting proved to be sufficient. In winter-populations the number of birds older than one year is underestimated because these birds are less inclined to visit bird-feeders. Population fluctuations may be overestimated because birds learn to avoid mist-nets. It is discussed how mist-netting can contribute to solve problems concerning population dynamics, migration, dispersal, invasion and settlement in Great Tits.相似文献
993.
KH Storbeck AC Swart N Lombard CV Adriaanse P Swart 《The Journal of steroid biochemistry and molecular biology》2012,132(3-5):311-321
Cytochrome b(5) (cyt-b(5)) is a ubiquitous hemoprotein also associated with microsomal cytochrome P450 17α-hydroxylase/17,20 lyase (CYP17A1). In the steroidogenic pathway CYP17A1 catalyses the metabolism of pregnenolone, yielding both glucocorticoid and androgen precursors. While not affecting the 17α-hydroxylation of pregnenolone, cyt-b(5) augments the 17,20 lyase reaction of 17-hydroxypregnenolone, catalyzing the formation of DHEA, through direct protein-protein interactions. In this study, multimeric complex formation of cyt-b(5) and the possible regulatory role of these complexes were investigated. Cyt-b(5) was isolated from ovine liver and used to raise anti-sheep cyt-b(5) immunoglobulins. Immunochemical studies revealed that, in vivo, cyt-b(5) is primarily found in the tetrameric form. Subsequent fluorescent resonance energy transfer (FRET) studies in COS-1 cells confirmed the formation of homomeric complexes by cyt-b(5) in live cells. Site-directed mutagenesis revealed that the C-terminal linker domain of cyt-b(5) is vital for complex formation. The 17,20-lyase activity of CYP17 was augmented by truncated cyt-b(5), which is unable to form complexes when co-expressed in COS-1 cells, thereby implicating the monomeric form of cyt-b(5) as the active species. This study has shown for the first time that cyt-b(5) forms homomeric complexes in vivo, implicating complex formation as a possible regulatory mechanism in steroidogenesis. 相似文献
994.
995.
Tim Raber Thomas Gorontzy Magarete Kleinschmidt Klaus Steinbach Karl-Heinz Blotevogel 《Current microbiology》1998,37(3):172-176
The ability of the strictly anaerobic sulfate-reducing bacterium Desulfobacula toluolica (strain Tol2) to cometabolically degrade p-toluidine (p-methylaniline) while using toluene as the primary source of carbon and energy has been studied. This organism has been shown
to modify and degrade toluidine in dense cell suspensions when no other source of carbon and energy is added. The metabolism
led to the formation of a variety of metabolites. From these metabolites a biphenyl-like compound as well as phenylacetic
acid have been identified by means of HPLC/MS techniques. The probable conversion of p-toluidine to p-aminophenylacetic acid and phenylacetic acid as dead end products suggested that this organism initiates p-toluidine degradation by the carboxylation of the methyl group. If this could be validated in further experiments, it would
be the first time that a toluidine was carboxylated at the methyl moiety by an anaerobic, sulfate-reducing bacterium.
Received: 6 March 1998 / Accepted: 3 April 1998 相似文献
996.
Burkhard Fleckenstein Karl-Heinz Wiesmüller Manfred Brich Günther Jung 《Letters in Peptide Science》1994,1(3):117-126
Summary Fast and convenient binding assays using synthetic peptides are of utmost and increasing importance, especially in the search for lead structures or in the field of diagnostics. A polymeric support suitable for solid-phase peptide synthesis was functionalized with two different anchor groups. The interior part of the aminomethylated polystyrene-1%-divinylbenzene resin beads, comprising about 98% of the total loading capacity, was modified by the acid-labile ADPV anchor whereas the 2% outer surface of the polymer was covalently coated with a PEG 10 000 derivative which renders the resin surface hydrophilic and biocompatible. The novel resin was characterized by introducing marker amino acids and by infrared spectroscopy. Employing this bifunctionalized resin for peptide synthesis, free as well as polymer-bound peptides were obtained which were tested for recognition by antibody. The resin-bound peptides proved to be suitable for ELISA and fluorescence assays, as shown by confocal laser microscopic investigations. Peptides from the interior part were obtained in high yield and purity as analyzed by HPLC, electrospray mass spectrometry and Edman degradation. 相似文献
997.
998.
Jürgen Hummel Patrick Steuer Karl-Heinz Südekum Sven Hammer Catrin Hammer W Jürgen Streich Marcus Clauss 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2008,149(2):142-149
Retention time of food in the digestive tract is a major aspect describing the digestive physiology of herbivores. Differences in feed retention times have been described for different ruminant feeding types. In this study, a dominantly grazing desert ruminant, the addax (Addax nasomaculatus), was investigated in this respect. Eight animals with a body weight (BW) of 87+/-5.3 kg on an ad libitum grass hay (Chloris gayana) diet were available. Co-EDTA and Cr-mordanted fibers (<2 mm) were used as pulse-dose markers. Mean retention time (MRT) in the digestive tract was calculated from faecal marker excretion. Average daily intake of the addax was found to be 1.7 kg dry matter (DM) or 60+/-8.3 g DM/kg BW(0.75). The MRT of fluid and particles in the reticulo-rumen (MRT(fluid)RR and MRT(particle)RR) were quantified to be 20+/-5.8 and 42+/-7.0 h respectively. When compared to literature data, MRT(fluid)RR was significantly longer than in cattle species, and MRT(particle)RR was significantly longer than in 11 taxa of all feeding types. The ratio of MRT(particle)RR/MRT(fluid)RR (2.3+/-0.5) was found to be within the range described for grazing ruminants. The long retention times found in the addax can be interpreted as an adaptation to a diet including a high proportion of slow fermenting grasses, while the long retention time of the fluid phase can be interpreted as a consequence of water saving mechanisms of the desert-adapted addax with a potentially low water turnover and capacious water storing rumen. 相似文献
999.
1000.
The anterior sternal epithelium of terrestrial isopods transports cuticular Ca(2+) to and from large sternal CaCO(3) deposits. We analyzed the anterior and posterior sternal epithelium by the means of the freeze-etch technique and measured the size distribution and density of intramembrane particles (IMPs) during three different molting stages. At least three IMP size classes around 4.5, 7.7, and 9.4 nm can be distinguished on the P-face of the apical and basolateral plasma membrane. An additional size class of around 12.8 nm is restricted to the apical compartment. In the anterior sternal epithelium, the density of these large particles changes by a factor of 1.9 during the molt cycle, suggesting a role in CaCO(3) formation and/or resorption. The density of the smaller IMPs rises transiently by a factor of 1.3 in the posterior sternal epithelium only. The IMP density of the basolateral plasma membrane increases significantly by a factor of 1.4 and 1.3 in the anterior and posterior sternal epithelia, respectively. The results indicate that increases in the IMP density contribute to the differentiation to an increased transport activity during the cyclic enlargements of the plasma membrane surface area in the anterior sternal epithelium. 相似文献