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141.
Luhua Zhang Ying Li Ke Dai Xintian Wen Rui Wu Xiaobo Huang Jin Jin Kui Xu Qigui Yan Yong Huang Xiaoping Ma Yiping Wen Sanjie Cao 《PloS one》2015,10(5)
Haemophilus parasuis, belonging to the family Pasteurellaceae, is the causative agent of Glässer’s disease leading to serious economic losses. In this study, a successive markerless mutation system for H. parasuis using two sequential steps of natural transformation was developed. By the first homologous recombination, the target genes were replaced by a cassette carrying kanamycin resistance gene and sacB (which confers sensitivity to sucrose) gene using kanamycin selection, followed by the second reconstruction to remove the selection cassette, with application of sucrose to further screen unmarked mutants. To improve DNA transformation frequency, several parameters have been analyzed further in this work. With this method, two unmarked deletions in one strain have been generated successfully. It is demonstrated that this system can be employed to construct multi-gene scarless deletions, which is of great help for developing live attenuated vaccines for H. parasuis. 相似文献
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弥勒苣苔为中国特有的濒危植物,一度被认为灭绝后又被重新发现,引起了学界及公众的广泛关注。种子库是保护珍稀濒危物种的一种有效手段,对物种开展种子保存需要较为深入的了解其种子休眠及萌发特性;但对于弥勒苣苔,现有资料十分有限,本研究系统地探讨了弥勒苣苔种子的休眠状态及萌发习性。在对其种子进行X光透视后,发现其种子的胚发育完全,且基本充满整个种子,因此认为该种子不具有形态休眠。在多个变温及恒温条件下对新鲜种子进行萌发测试,发现在较高温度(高于20℃)下萌发率很高且萌发迅速,赤霉素及低温层积处理能够显著提高种子在较低温度下(低于20℃)的萌发率,因此可以判定其种子存在浅的生理休眠。种子在恒温下的萌发率比相应的变温下萌发率要高,可能是其对所处荫蔽环境的一种适应。硝酸钾对种子萌发有显著的促进作用,在野外环境下,硝酸钾有对生境空窗及较少竞争的指示作用。 相似文献
145.
Tianyu Li Yang Chen Jie Li Xiaobo Yang Haiying Zhang Xue Qin Yanling Hu Zengnan Mo 《PloS one》2015,10(9)
Recent studies suggest that serum homocysteine (HCY) level is correlated to inflammatory/immune factors that influence the development and progression of many diseases, such as cardiovascular disease. However, the association between serum HCY level and inflammatory/immune factors in healthy populations has not been systematically investigated. This study was conducted based on the Fangchenggang Area Male Health and Examination Survey (FAMHES) project. After comprehensive baseline analysis, we could not find any significant association between HCY level and inflammatory/immune factors. However, in the next linear regression analysis, serum C4 [age-adjusted: Beta = -0.053, 95%CI = (-3.798, -0.050), P = 0.044; multivariate adjusted: Beta = -0.064, 95%CI = (-4.271, -0.378), P = 0.019] and C-reactive protein (CRP) concentration [unadjusted: Beta = 0.056, 95%CI = (0.037, 0.740), P = 0.030] were positively related with HCY. In further binary regression analysis, a significant correlation was confirmed for C4 and HCY [age-adjusted: OR = 0.572, 95%CI = (0.359, 0.911); multivariate adjusted: OR = 0.558, 95%CI = (0.344, 0.905)]. In order to discover more potential associations, multivariate logistic regression analysis was applied and suggested that HCY and C4 were significantly correlated [age-adjusted: OR = 0.703, 95%CI = (0.519, 0.951); multivariate adjusted: OR = 0.696, 95%CI = (0.509, 0.951)]. In addition, immunoglobulin M (IgM) may influence the HCY level to some extent [unadjusted: OR = 1.427, 95%CI = (1.052, 1.936); age-adjusted: OR = 1.446, 95%CI = (1.061, 1.970); multivariate adjusted: OR = 1.447, 95%CI = (1.062, 1.973)]. Combining our results with recent studies, we propose that C4, CRP, and IgM in serum are significantly associated with HCY concentration. Further studies are needed on the mechanism of the interaction, especially among cardiovascular disease subjects. 相似文献
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147.
Hua Jin Xun Huang Yong Chen Hongxia Zhao Hongyan Ye Feicheng Huang Xiaobo Xing Jiye Cai 《Applied microbiology and biotechnology》2010,88(3):761-770
The photodynamic antimicrobial chemotherapy as a promising approach for efficiently killing pathogenic microbes is attracting
increasing interest. In this study, the cytotoxic and phototoxic effects of hematoporphyrin monomethyl ether (HMME) on the
Gram-positive and Gram-negative bacteria were investigated. The cell viability was assessed by colony-forming unit method,
and the results indicated that there was no significant cytotoxicity but high phototoxicity in the examined concentrations.
Notably, the Gram-positive bacteria were more sensitive to HMME in phototoxicity. Simultaneously, an atomic force microscope
(AFM) was used to detect the changes in morphological and nanomechanical properties of bacteria before and after HMME treatment.
AFM images indicate that upon photoinactivation, the bacterial surface changed from a smooth, homogeneous architecture to
a heterogenous, crackled morphology. The force spectroscopy measurements reveal that the cell wall became less rigid and the
Young’s modulus decreased about 50%, whereas the tip-cell-surface adhesion forces increased significantly compared to those
of native cells. It was speculated that the photodynamic effects of HMME induced the changes in the chemical composition of
the outer membrane and exposure of some proteins inside the envelope. AFM can be utilized as a powerful and sensitive method
for studying the interaction between bacteria and drugs. 相似文献
148.
Lihong Wang Hao Li Zhen Liu Xiaobo Xu Huaijing Wang Zhenzhong Li 《Cellular and molecular neurobiology》2010,30(1):43-49
The neuropeptide-immunoreactive (IR) and neurofilament-IR neurons are two major phenotypical classes in dorsal root ganglion
(DRG). Targets of neuronal innervation play a vital role in regulating the survival and differentiation of innervating neurotrophin-responsive
neurons. Monosialoganglioside (GM1) has been considered to have a neurotrophic factor-like activity. Both GM1 and target skeletal
muscle (SKM) cells are essential for the maintenance of the function of neurons. However, whether target SKM cells and GM1,
alone or associated, generate neuropeptide or neurofilament expression remains unclear. The aim of the present study is to
investigate the effects of GM1 or/and SKM on DRG neuronal phenotypes. DRG neurons containing the neuropeptide substance P
(SP) and neurofilament 200 (NF-200) were quantified using immunofluorescent labeling in cultures of DRG, which was dissected
out at times before (at embryonic days 12.5, E12.5) and after (at E19.5) sensory neurons contact peripheral targets in vivo.
DRG neurons were cultured in absence or presence of GM1 or/and SKM cells. In this experiment, we found that: (1) GM1 promoted
expression of SP and NF-200 in E12.5 DRG cultures; (2) SKM cells promoted expression of NF-200 but not SP in E12.5 DRG cultures;
(3) GM1 and target SKM cells had additive effects on expression of SP and NF-200 in E12.5 DRG cultures; and (4) SKM or/and
GM1 did not have effects on expression of SP and NF-200 in E19.5 DRG cultures. These results suggested that GM1 could influence
DRG, two major neuronal phenotypes, before sensory neurons contact peripheral targets in vivo. Target SKM cells could only
influence neurofilament-expressed neuronal phenotype before sensory neurons contact peripheral targets in vivo. GM1 and SKM
cells had the additive effects on two major DRG neuronal classes, which express neuropeptide or neurofilament when DRG cells
were harvested before sensory neurons contact peripheral targets in vivo. These results offered new clues for a better understanding
of the association of GM1 or/and SKM with neuronal phenotypes. 相似文献
149.
Patrick Collombat Xiaobo Xu Harry Heimberg Ahmed Mansouri 《Seminars in cell & developmental biology》2010,21(8):838-844
The pancreas is composed of two main compartments consisting of endocrine and exocrine tissues. The majority of the organ is exocrine and responsible for the synthesis of digestive enzymes and for their transport via an intricate ductal system into the duodenum. The endocrine tissue represents less than 2% of the organ and is organized into functional units called islets of Langerhans, comprising alpha-, beta-, delta-, epsilon- and PP-cells, producing the hormones glucagon, insulin, somatostatin, ghrelin and pancreatic polypeptide (PP), respectively. Insulin-producing beta-cells play a central role in the control of the glucose homeostasis. Accordingly, absolute or relative deficiency in beta-cells may ultimately lead to type 1 and/or type 2 diabetes, respectively. One major goal of diabetes research is therefore to understand the molecular mechanisms controlling the development of beta-cells during pancreas morphogenesis, but also those underlying the regeneration of adult injured pancreas, and assess their significance for future cell-based therapy. In this review, we will therefore present new insights into beta-cell development with focus on beta-cell regeneration. 相似文献
150.
Yu Z Liu L Yu X Chi J Han H Liu Y He W Sun Q Gao J Xu D 《Journal of biomolecular screening》2010,15(10):1260-1267
In this work, the authors developed a new screening approach using multiplexed immunization and immunogen array analysis to improve the efficiency of antibody screening for high-throughput antibody generation. The immunogen array is based on a 96-well format in which different immunogens and negative as well as positive controls are immobilized in each well, thus making it possible to screen hundreds of antibody candidates simultaneously. To demonstrate this approach, a model of 4 mixed immunogens immunization was employed. In total, 675 antibody candidates were screened before and after established antibody hybridomas in parallel with immunogen arrays and enzyme-linked immunosorbent assay. The signal intensity, specificity, and cross-reactivity of produced antibody candidates were analyzed using a hierarchical cluster algorithm to track the characteristics of antibody candidates during antibody generation, which might reduce the number of false-positive and false-negative binding of antibodies. Moreover, 4 monoclonal antibodies that were produced successfully recognized their corresponding target antigens. 相似文献