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991.
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Werner Hummel 《Biotechnology letters》1990,12(6):403-408
Summary A dehydrogenase catalyzing the NADPH-dependent reduction of acetophenone to R(+)-phenylethanol was found inLactobacillus kefir. A continuous conversion of 10 mM acetophenone with a yield of up to 90% was achieved in an enzyme-membrane-reactor with simultaneous NADPH-regeneration using glucose-6-phosphate and glucose-6-phosphate dehydrogenase. Enzyme-catalyzed oxidation of phenylethanol occurred with the R(+)-enantiomer only, whereas S(–) was not converted by the enzyme. The formation of R(+)-phenylethanol with an enantiomeric excess of 100% was confirmed by chiral HPLC. 相似文献
994.
Comparative in situ hybridization in various primate species has revealed a pseudoautosomal location for the human ANT3 gene and an X-specific location for the steroid sulfatase (STS) gene throughout the higher primate species up to the New World monkeys. However, ANT3 and STS map together on an autosome of two prosimian species of the genus Lemur and Eulemur. These results suggest an autosome-to-X/Y translocation after the simians radiated from the prosimians, resulting in a pseudoautosomal location of genes such as ANT3 and STS. In simian primates, STS then became X-specific by a pericentric inversion in the Y chromosome followed by mutational inactivation of the Y allele. 相似文献
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998.
Juvenile noble crayfish,
Astacusastacus
(Crustacea, Astacidea) in the second year of age were kept in the laboratory for a twelve-month period under continuing “summer conditions” (LD 16:8, 19°C). Molting processes in this population could be synchronized by artificial moonlight cycles. Peaks of exuviations occurred at “new moons”. Males showed a slightly higher degree of synchronization than females. A phase-shift of the artificial lunar cycle in relation to the natural cycle resulted in a corresponding shift of the molting cycle. This clearly demonstrates that changes in the nocturnal light regime provide the primary external information for the lunar-monthly molting rhythm. There is a first indication that lunar photic stimuli do not act directly but as a zeitgeber which entrains an endogenous molting rhythm to the lunar cycle. Moreover, the results of the long-term experiments suggest that the hibernal resting period of
A
. astacus
in the field (no molts between October and April) may also involve some endogenous programming. Continuing artificial summer conditions can delay but not completely suppress this resting period. The adaptive significance of the phenomena and how the findings may be applied to improve the management of crowded crayfish stocks are discussed. 相似文献
999.
Felix Schneider Melanie Hoppe Mirko Koziolek Werner Weitschies 《AAPS PharmSciTech》2018,19(7):2843-2850
Despite extensive research in the field of gastroretentive dosage forms, this “holy grail” of oral drug delivery yet remained an unmet goal. Especially under fasting conditions, the reproducible retention of dosage forms in the stomach seems to be an impossible task. This is why such systems are often advised to be taken together with food. But also the postprandial motility can contribute significantly to the failure of gastroretentive dosage forms. To investigate the influence of postprandial pressure conditions on drug release from such systems, we used a novel in vitro dissolution tool, the dissolution stress test device. With the aid of this device, we simulated three different intragastric pressure profiles that may occur after postprandial intake. These transit scenarios were based on recently obtained, postprandial SmartPill® data. The tested systems, Glumetza® 1000 and Madopar® HBS 125, are marketed dosage forms that are based on different approaches to achieve proper gastric retention. All three transit scenarios revealed a highly pressure-sensitive drug release behavior, for both drugs. For Madopar® HBS 125, nearly complete drug release was observed even after early occurring pressures. Glumetza® 1000 seemed to be more resistant to these, most likely due to incomplete wetting of the system. On the contrary to these findings, data from standard dissolution tests using the paddle apparatus displayed controlled drug release for both systems for about 6 h. Based on these results, it can be doubted that established gastroretentive systems stay intact over a longer period of time, even under postprandial conditions. 相似文献
1000.
Vanessa Drendel Bianca Heckelmann Christoph Schell Lucas Kook Martin L. Biniossek Martin Werner Cordula A. Jilg Oliver Schilling 《Clinical proteomics》2018,15(1):25