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271.
272.
Qian Lu Chong Wang Rong Pan Xinghua Gao Zhifeng Wei Yufeng Xia Yue Dai 《Journal of cellular biochemistry》2013,114(5):1009-1019
Histamine, a major mediator present in mast cells that is released into the extracellular milieu upon degranulation, is well known to possess a wide range of biological activities in several classic physiological and pathological processes. However, whether and how it participates in angiogenesis remains obscure. In the present study, we observed its direct and synergistic action with basic fibroblast growth factor (bFGF), an important inducer of angiogenesis, on in vitro angiogenesis models of endothelial cells. Data showed that histamine (0.1, 1, 10 µM) itself was absent of direct effects on the processes of angiogenesis, including the proliferation, migration, and tube formation of endothelial cells. Nevertheless, it could concentration‐dependently enhance bFGF‐induced angiogenesis as well as production of vascular endothelial growth factor (VEGF) from endothelial cells. The synergistic effect of histamine on VEGF production could be reversed by pretreatments with diphenhydramine (H1‐receptor antagonist), SB203580 (selective p38 mitogen‐activated protein kinase (MAPK) inhibitor) and L ‐NAME (nitric oxide synthase (NOS) inhibitor), but not with cimetidine (H2‐receptor antagonist) and indomethacin (cyclooxygenase (COX) inhibitor). Moreover, histamine could augment bFGF‐incuced phosphorylation and degradation of IκBα, a key factor accounting for the activation and translocation of nuclear factor κB (NF‐κB) in endothelial cells. These findings indicated that histamine was able to synergistically augment bFGF‐induced angiogenesis, and this action was linked to VEGF production through H1‐receptor and the activation of endothelial nitric oxide synthase (eNOS), p38 MAPK, and IκBα in endothelial cells. J. Cell. Biochem. 114: 1009–1019, 2013. © 2012 Wiley Periodicals, Inc. 相似文献
273.
274.
Biological removal of carbon, nitrogen and sulfur is drawing increasing research interest in search for an efficient and cost-effective wastewater treatment. While extensive work on separate removal of nitrogen and sulfur is well documented, investigation on simultaneous denitrifying sulfide removal has only been reported recently. Most of the work on denitrifying sulfide removal has been focusing on bioreactor performance, loading and operating conditions. Nonetheless, underlying principles elucidating the biochemical reactions and the mechanisms of the microbial degradation are yet to be established. In addition, unstable denitrifying sulfide removal which is a major operating problem that hinders practical application of the process, is yet to be resolved. This paper provides a review on the state-of-the-art development of simultaneous biological removal of sulfur, nitrogen and carbon. Research on bioreactor operation and performance, reactor configurations, mechanisms and modeling work including the use of mass balance analysis and artificial neural networks is delineated. An in-depth discussion on the microbial community and functional consortium is also provided. Challenges and future work on simultaneous biological removal of nitrogen–sulfur–carbon are also outlined. 相似文献
275.
Xing Pan Xiao-Jun Li Xi-Juan Liu Hui Yuan Jia-Fu Li Ying-Liang Duan Han-Qing Ye Ya-Ru Fu Guan-Hua Qiao Cong-Cong Wu Bo Yang Xiao-Hui Tian Kang-Hong Hu Ling-Feng Miao Xiao-Ling Chen Jun Zheng Simon Rayner Philip H. Schwartz William J. Britt Jiang Xu Min-Hua Luo 《Journal of virology》2013,87(20):10968-10979
Congenital human cytomegalovirus (HCMV) infection is the most frequent infectious cause of birth defects, primarily neurological disorders. Neural progenitor/stem cells (NPCs) are the major cell type in the subventricular zone and are susceptible to HCMV infection. In culture, the differentiation status of NPCs may change with passage, which in turn may alter susceptibility to virus infection. Previously, only early-passage (i.e., prior to passage 9) NPCs were studied and shown to be permissive to HCMV infection. In this study, NPC cultures derived at different gestational ages were evaluated after short (passages 3 to 6) and extended (passages 11 to 20) in vitro passages for biological and virological parameters (i.e., cell morphology, expression of NPC markers and HCMV receptors, viral entry efficiency, viral gene expression, virus-induced cytopathic effect, and release of infectious progeny). These parameters were not significantly influenced by the gestational age of the source tissues. However, extended-passage cultures showed evidence of initiation of differentiation, increased viral entry, and more efficient production of infectious progeny. These results confirm that NPCs are fully permissive for HCMV infection and that extended-passage NPCs initiate differentiation and are more permissive for HCMV infection. Later-passage NPCs being differentiated and more permissive for HCMV infection suggest that HCMV infection in fetal brain may cause more neural cell loss and give rise to severe neurological disabilities with advancing brain development. 相似文献
276.
Zhechen Qi Kenneth M. Cameron Pan Li Yunpeng Zhao Shichao Chen Guangcun Chen Chengxin Fu 《Botanical journal of the Linnean Society. Linnean Society of London》2013,173(4):535-548
Smilacaceae, composed of Smilax and Heterosmilax, are a cosmopolitan family of > 200 species of mostly climbing monocots with alternate leaves characterized by reticulate venation, a pair of petiolar tendrils and usually prickly stems. Although there has been a long history of studying Smilax since Linnaeus named the genus in 1753, the phylogenetic history of this dioecious family remains unclear. Here we present results based on nuclear ribosomal internal transcribed spacer (nrITS) and plastid matK and rpl16 intron DNA sequence data from 125 taxa of Smilacaceae. Our taxon sampling covers all sections of Smilax and Heterosmilax and major distribution zones of the family; species from Ripogonaceae and Philesiaceae are used as outgroups. Our molecular analysis indicates that phylogenetic relationships largely contradict the traditional morphological classification of the family, instead showing a conspicuous geographical pattern among the species clades. The previously recognized genus Heterosmilax was found to be embedded in Smilax. Species in the family are separated into primarily New World and Old World clades, except for a single species lineage, Smilax aspera, that is sister to the remaining species of the family, but with poor statistical support. Ancestral character state reconstructions and examination of distribution patterns among the clades provide important information for future taxonomic revisions and historical biogeography of the group. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 535–548. 相似文献
277.
Hai-Xue Pan Ji-An Li Lei Shao Chun-Bao Zhu Jun-Sheng Chen Gong-Li Tang Dai-Jie Chen 《Biotechnology letters》2013,35(1):107-114
Ramoplanins produced by Actinoplanes are new structural class of lipopeptide and are currently in phase III clinical trials for the prevention of vancomycin-resistant enterococcal infections. The depsipeptide structures of ramoplanins are synthesized by non-ribosomal peptide synthetases (NRPS). Romo-orf17, a stand-alone NRPS, is responsible for the recruitment of Thr into the linear NRPS pathways for which the corresponding adenylation domain is absent. Here, systematical gene inactivation and complementation have been carried out in a Actinoplanes sp. using homologous recombination and site-specific integration methods. A hybrid gene coding for the N-terminal region of the stand-alone NRPS and the A-PCP domains of a heterologous NRPS restored production of ramoplanins. The results elucidate the unusual N-terminal region which is essential for the biosynthesis of ramoplanins. 相似文献
278.
Jun-Sheng Chen Yuan-Xi Wang Lei Shao Hai-Xue Pan Ji-An Li Hui-Min Lin Xiao-Jing Dong Dai-Jie Chen 《Biotechnology letters》2013,35(9):1501-1508
Ramoplanin is a lipopeptide antibiotic active against multi-drug-resistant, Gram-positive pathogens. Structurally, it contains a di-mannose moiety attached to the peptide core at Hpg11. The biosynthetic gene cluster of ramoplanin has already been reported and the assembly of the depsipeptide has been elucidated but the mechanism of transferring sugar moiety to the peptide core remains unclear. Sequence analysis of the biosynthetic gene cluster indicated ramo-orf29 was a mannosyltransferase candidate. To investigate the involvement of ramo-orf29 in ramoplanin biosynthesis, gene inactivation and complementation have been conducted in Actinoplanes sp. ATCC 33076 by homologous recombination. Metabolite analysis revealed that the ramo-orf29 inactivated mutant produced no ramoplanin but the ramoplanin aglycone. Thus, ramo-orf29 codes for the mannosyltransferase in the ramoplanin biosynthesis pathway. This lays the foundation for further exploitation of the ramoplanin mannosyltransferase and aglycone in combinatorial biosynthesis. 相似文献
279.
Xiao K. Wang Qiu F. Ma Wei Jiang Jing Lv Wei D. Pan Tao Song 《Geomicrobiology journal》2013,30(6):296-303
Magnetotactic bacteria synthesize intracellular magnetic particles, magnetosomes, which arrange in chain(s) and confer on cell a magnetic dipolar moment. To explore the function of geomagnetic field to magnetotactic bacteria, the effects of hypomagnetic field on magnetosome formation in Magnetospirillum magneticum AMB-1 were studied. Cells were cultivated in a specially designed device where geomagnetic field was reduced by about 100-fold to less than 500nT. AMB-1 cultures were incubated in hypomagnetic field or geomagnetic field. Results showed that hypomagnetic field had no significant effects on the average number of magnetic particles per bacterium and bacterial iron depletion. However, the growth (OD) of cell at stationary-phase was lower and cellular magnetism (R mag) at exponential growth phase was higher than that of bacteria cultivated in geomagnetic field. Statistic results on transmission electron microscopy (TEM) micrographs showed that the average size of magnetic particles in AMB-1 cells in hypomagnetic field group was larger than that of in geomagnetic field group and more ratio of larger-size magnetic particles (>50 nm) was observed when cultivated 16 h under hypomagnetic field. Furthermore, the influences of hypomagnetic field on gene expression were studied in AMB-1 cells. Quantitative RT-PCR results showed that hypomagnetic field up-regulated mms13, down-regulated mms6 and had no effect on magA. Together, the results showed that hypomagnetic field could affect the growth of AMB-1 at the stationary-phase, the crystallization process of magnetosomes, and mms13, mms6 expressions. In addition, our results suggested that the geomagnetic field plays an important role in the biomineralization of magnetosomes. 相似文献
280.