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Yuan Lu Hongxin Zhao Chong Zhang Qiheng Lai Xi Wu Xin-Hui Xing 《Biotechnology letters》2009,31(10):1525-1530
An expression system for NAD+-dependent formate dehydrogenase gene (fdh1), from Candida boidinii, was constructed and cloned into Enterobacter aerogenes IAM1183. With the fdh1 expression, the total H2 yield was attributed to a decrease in activity of the lactate pathway and an increase of the formate pathway flux due to
the NADH regeneration. Analysis of the redox state balance and ethanol-to-acetate ratio in the fdhl-expressed strain showed that increased reducing power arose from the reconstruction of NADH regeneration pathway from formate
thereby contributing to the improved H2 production. 相似文献
995.
Xi Peng Yun Cui Wei Cui Junliang Deng Hengmin Cui 《Biological trace element research》2009,131(1):33-42
Selenium is an essential trace element possessing immune-stimulatory properties. The purpose of this 42-day study was to investigate
the effects of excess dietary sodium selenite on immune function by determining morphological changes and apoptosis of bursa
of Fabricius. Three hundred 1-day-old Avian broilers were fed on a basic diet (0.2 ppm selenium) or the same diet amended
to contain 1, 5, 10, and 15 ppm selenium supplied as sodium selenite (n = 60/group). Relative weight of bursa was significantly decreased in the 1, 5, 10, and 15 ppm groups at 28 days of age, when
compared with that of 0.2 ppm group. Pathological lesions were progressed with the dietary Se level increased. The gross lesions
of bursa involved obvious atrophy with decreased volume and pale color. Histopathologically, decreased number of lymphocytes
and loosely packed lymphocytes appeared in the medulla and cortex in the follicles. Ultrastructurally, mitochondria injury
and increased apoptotic cells with condensed nuclei were observed. In comparison to that of control group, excess Se (5, 10,
and 15 ppm) intake increased the percentage of Annexin V positive cells, as measured by flow cytometry. Terminal deoxynucleotidyl
transferase 2′-deoxyuridine 5′-triphosphate nick end-labeling assay showed that there were increased frequencies of apoptotic
cells in 10 and 15 ppm selenium groups. These data suggest that Se supplementation with sodium selenite should be carefully
evaluated as excess selenium (more than 5 ppm) intake could cause profound immunologic inhibition. 相似文献
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Yong‐Chun Wang Shu Zhang Ting‐Yuan Du Bing Wang Xi‐Qing Sun 《Journal of cellular biochemistry》2009,107(2):357-363
Alterations of nitric oxide contribute to post‐flight orthostatic intolerance. The aim of this study was to investigate the changes of inducible nitric oxide synthase (iNOS) and the mechanisms underlying regulation of iNOS by simulated microgravity in human umbilical vein endothelial cells (HUVECs). Clinorotation, a simulated‐model of microgravity, increased iNOS expression and promoter activity in HUVECs. The transactivations of NF‐κB and AP‐1 were suppressed by 24 h clinorotation. A key role for AP‐1, but not NF‐κB in the regulation of iNOS was shown. (1) PDTC, a NF‐κB inhibitor, had no effect on clinorotation upregulation of iNOS. (2) SP600125, a JNK‐specific inhibitor, which resulted in inhibition of AP‐1 activity, enhanced the iNOS expression and promoter activity in clinorotation. (3) Overexpression of AP‐1 remarkably attenuated the upregulation effect of clinorotation. These findings indicate that clinorotation upregulates iNOS in HUVECs by a mechanism dependent on suppression of AP‐1, but not NF‐κB. These results support a key role for AP‐1 in the signaling of postflight orthostatic intolerance. J. Cell. Biochem. 107: 357–363, 2009. © 2009 Wiley‐Liss, Inc. 相似文献
998.
Yan Gong Hong-Nong Chou Chi-dao Tu Xi Liu Jiantong Liu Lirong Song 《Journal of applied phycology》2009,21(2):225-231
Arsenic pollution and eutrophication are both prominent issues in the aquaculture ponds of Taiwan. It is important to study
the effects of arsenic on algal growth and toxin production in order to assess the ecological risk of arsenic pollution, or
at least to understand naturally occurring ponds. The sensitivity of algae to arsenate has often been linked to the structural
similarities between arsenate and phosphate. Thus, in this study we examined the effects of arsenate (10−8 to 10−4 M) on Microcystis aeruginosa TY-1 isolated from Taiwan, under two phosphate regimes. The present study showed that M. aeruginosa TY-1 was arsenate tolerant up to 10−4 M, and that this tolerance was not affected by extracellular phosphate. However, it seems that extracellular phosphate contributed
to microcystin production and leakage by M. aeruginosa in response to arsenate. Under normal phosphate conditions, total toxin yields after arsenate treatment followed a typical
inverted U-shape hormesis, with a peak value of 2.25 ± 0.06 mg L−1 in the presence of 10−7 M arsenate, whereas 10−8 to 10−6 M arsenate increased leakage of ∼75% microcystin. Under phosphate starvation, total toxin yields were not affected by arsenate,
while 10−6 and 10−5 M arsenate stimulated microcystin leakage. It is suggested that arsenate may play a role in the process of microcystin biosynthesis
and excretion. Given the arsenic concentrations in aquaculture ponds in Taiwan, arsenate favors survival of toxic M. aeruginosa in such ponds, and arsenate-stimulated microcystin production and leakage may have an impact on the food chain. 相似文献
999.
Four linear thiourea anion receptors (1-3) derived from simple amino acid have been synthesized and their bonding properties with various chiral N-protected amino acid anions were examined by using UV-vis and fluorescence titration experiments. Receptors 1a, 2, and 3 exhibit excellent enantioselective recognition abilities towards N-Boc-protected alanine anion in the UV-vis spectra, obvious difference in the color of solution indicate that the enantiomers of N-Boc-alanine anion could be distinguished by naked eye directly. Receptor 1a is also found to carry out enantioselective fluorescent recognition of the N-acetyl-glutamate. (1)H NMR experiments suggest that hydrogen-bonding interaction between the host and guest is the main factor in the recognition process. 相似文献
1000.