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111.
Yuxin Zhang Zhonglong Liu Kexin Wang Shenji Lu Shuai Fan Lili Xu Bin Cai 《International journal of biological sciences》2021,17(7):1837
Joint capsule fibrosis caused by excessive inflammation results in post-traumatic joint contracture (PTJC). Transforming growth factor (TGF)-β1 plays a key role in PTJC by regulating fibroblast functions, however, cytokine-induced TGF-β1 expression in specific cell types remains poorly characterized. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine involved in inflammation- and fibrosis-associated pathophysiology. In this study, we investigated whether MIF can facilitate TGF-β1 production from fibroblasts and regulate joint capsule fibrosis following PTJC. Our data demonstrated that MIF and TGF-β1 significantly increased in fibroblasts of injured rat posterior joint capsules. Treatment the lesion sites with MIF inhibitor 4-Iodo-6-phenylpyrimidine (4-IPP) reduced TGF-β1 production and relieved joint capsule inflammation and fibrosis. In vitro, MIF facilitated TGF-β1 expression in primary joint capsule fibroblasts by activating mitogen-activated protein kinase (MAPK) (P38, ERK) signaling through coupling with membrane surface receptor CD74, which in turn affected fibroblast functions and promoted MIF production. Our results reveal a novel function of trauma-induced MIF in the occurrence and development of joint capsule fibrosis. Further investigation of the underlying mechanism may provide potential therapeutic targets for PTJC. 相似文献
112.
Hongwei Gu Xuwang Cai Xinyang Zhang Jie Luo Xiaoyang Zhang Xiao Hu Wentong Cai Ganwu Li 《PLoS pathogens》2021,17(10)
Uropathogenic Escherichia coli (UPEC) deploy an array of virulence factors to successfully establish urinary tract infections. Hemolysin is a pore-forming toxin, and its expression correlates with the severity of UPEC infection. Two-component signaling systems (TCSs) are a major mechanism by which bacteria sense environmental cues and respond by initiating adaptive responses. Here, we began this study by characterizing a novel TCS (C3564/C3565, herein renamed orhK/orhR for oxidative resistance and hemolysis kinase/regulator) that is encoded on a UPEC pathogenicity island, using bioinformatic and biochemical approaches. A prevalence analysis indicates that orhK/orhR is highly associated with the UPEC pathotype, and it rarely occurs in other E. coli pathotypes tested. We then demonstrated that OrhK/OrhR directly activates the expression of a putative methionine sulfoxide reductase system (C3566/C3567) and hemolysin (HlyA) in response to host-derived hydrogen peroxide (H2O2) exposure. OrhK/OrhR increases UPEC resistance to H2O2 in vitro and survival in macrophages in cell culture via C3566/C3567. Additionally, OrhK/OrhR mediates hemolysin-induced renal epithelial cell and macrophage death via a pyroptosis pathway. Reducing intracellular H2O2 production by a chemical inhibitor impaired OrhK/OrhR-mediated activation of c3566-c3567 and hlyA. We also uncovered that UPEC links the two key virulence traits by cotranscribing the c3566-c3567 and hlyCABD operons. Taken together, our data suggest a paradigm in which a signal transduction system coordinates both bacterial pathogen defensive and offensive traits in the presence of host-derived signals; and this exquisite mechanism likely contributes to hemolysin-induced severe pathological outcomes. 相似文献
113.
厦门凤林红树林湿地大型底栖动物群落 总被引:8,自引:0,他引:8
为摸清厦门集美凤林红树林湿地的大型底栖动物群落结构及其多样性现状,2002年1、4、7和10月在厦门集美凤林红树林区进行大型底栖动物调查,4个季度共获得大型底栖动物42种。生物量优势种是软体动物门的珠带拟蟹守螺(Cerithideacingulata)和节肢动物门的弧边招潮(Ucaarcuata)。密度优势种是软体动物门的短拟沼螺(Assimineabrevicula)和环节动物门的沼蚓(Limnodriloidessp.)。集美凤林红树林区大型底栖动物年平均密度和年平均生物量分别为1,990ind./m2和139.0g/m2。密度的季节变化是:1月>4月>10月>7月,生物量的季节变化是1月>10月>4月>7月。聚类分析和数量分布表明,优势种珠带拟蟹守螺、短拟沼螺、弧边招潮和沼蚓的季节变化各不相同。与2002年10月深圳湾福田红树林区大型底栖动物群落的物种多样性指数平均值(0.56)比较,厦门凤林红树林区的平均值较高(2.66)。文中分析了影响大型底栖动物多样性的环境因素。 相似文献
114.
Two novel metal-organic hybrid coordination polymers {[Cu(bpo)(chdc)(H2O)](H2O)0.5}n (1) and [Pb(chdc)(H2O)]n (2) have been synthesized under different conditions and structurally characterized by single-crystal X-ray diffraction technique, where H2chdc refers to a flexible 1,4-cyclohexanedicarboxylic acid ligand and bpo is 2,5-bis(4-pyridyl)-1,3,4-oxadiazole. Complex 1 has a two-dimensional (2-D) grid-like [11.28 × 13.63 Å2] framework in which the CuII centers are extended via bidentate bridging ligands bpo and e,e-trans-chdc along two directions, exhibiting large porous cavities. Coordination polymer 2 represents the first PbII complex of H2chdc in which the larger PbII centers are connected by e,a-cis-chdc anions to afford a 2-D close-knit structure. 相似文献
115.
L. W. Zhu P. Zhao X. A. Cai X. P. Zeng G. Y. Ni J. Y. Zhang L. L. Zou T. T. Mei M. H. Yu 《Trees - Structure and Function》2012,26(2):535-542
Stem CO2 efflux (E
s) has been estimated from a temperature-related equation, but sap flux often affects measurements of E
s, which leads to misunderstanding real stem respiration. In order to observe the relationship between E
s and stem temperature and to analyze the effect of sap velocity on E
s, stem temperature, E
s and sap flux were measured from a subtropical Schima superba plantation in South China on three trees for consecutive 3 days in July and October 2009. Stem temperature, E
s and sap velocity were significantly higher in July than in October. Stem temperature could explain 17–41 and 54–75% variations
of E
s in July and October, respectively. A negative relationship between E
s and stem temperature was found during 1800–2300 hours in July. The daytime E
s was 9.2, 4.3 and 2.4% higher than the predicted for three trees in July, and this occurred only on Tree 1 in October. Sap
velocity was positively correlated with E
s for three trees in July, and the increase of E
s with the increase of sap velocity was only observed on Tree 1 in October. These results demonstrated that the occurrence
of sap flux could account for the increase of daytime E
s, and the effect of sap velocity on E
s varied with the seasons from the S. superba stem. 相似文献
116.
【目的】为了研究青草沙水库中土著微生物对藻类生长的抑制作用,从水库水体中筛选出对藻类有抑制作用的细菌并研究其对铜绿微囊藻的抑制效果。【方法】通过对水库水体中的细菌进行划线分离和筛选,挑选出一株对铜绿微囊藻生长有较好抑制作用的菌株CL。考察其对铜绿微囊藻的抑制效果及不同培养时间和菌液浓度对抑藻效果的影响,并对菌株进行16S rDNA序列分析。【结果】实验菌液浓度为4.5×108CFU/mL 8.4×108CFU/mL时,细菌对铜绿微囊藻的抑制率可达45.4%。抑藻效果随培养时间先增后降,在静置培养第6天抑藻效果达到最大。该菌经过16S rDNA序列分析,属于黄单胞菌科的寡养单胞菌。【结论】从青草沙水库中筛选出了对铜绿微囊藻有抑制作用的土著细菌寡养单胞菌,对青草沙水体铜绿微囊藻的控制具有一定的潜在应用价值。 相似文献
117.
Jiang SY Bhalla R Ramamoorthy R Luan HF Venkatesh PN Cai M Ramachandran S 《Transgenic research》2012,21(4):785-795
Both drought and high salinity stresses are major abiotic factors that limit the yield of agricultural crops. Transgenic techniques have been regarded as effective ways to improve crops in their tolerance to these abiotic stresses. Functional characterization of genes is the prerequisite to identify candidates for such improvement. Here, we have investigated the biological functions of an Oryza sativa Ribosome-inactivating protein gene 18 (OSRIP18) by ectopically expressing this gene under the control of CaMV 35S promoter in the rice genome. We have generated 11 independent transgenic rice plants and all of them showed significantly increased tolerance to drought and high salinity stresses. Global gene expression changes by Microarray analysis showed that more than 100 probe sets were detected with up-regulated expression abundance while signals from only three probe sets were down-regulated after over-expression of OSRIP18. Most of them were not regulated by drought or high salinity stresses. Our data suggested that the increased tolerance to these abiotic stresses in transgenic plants might be due to up-regulation of some stress-dependent/independent genes and OSRIP18 may be potentially useful in further improving plant tolerance to various abiotic stresses by over-expression. 相似文献
118.
Nitrogen-15 Carr-Purcell-Meiboom-Gill (CPMG) transverse relaxation experiment are widely used to characterize protein backbone dynamics and chemical exchange parameters. Although an accurate value of the transverse relaxation rate, R(2), is needed for accurate characterization of dynamics, the uncertainty in the R(2) value depends on the experimental settings and the details of the data analysis itself. Here, we present an analysis of the impact of CPMG pulse phase alternation on the accuracy of the (15)N CPMG R(2). Our simulations show that R(2) can be obtained accurately for a relatively wide spectral width, either using the conventional phase cycle or using phase alternation when the r.f. pulse power is accurately calibrated. However, when the r.f. pulse is miscalibrated, the conventional CPMG experiment exhibits more significant uncertainties in R(2) caused by the off-resonance effect than does the phase alternation experiment. Our experiments show that this effect becomes manifest under the circumstance that the systematic error exceeds that arising from experimental noise. Furthermore, our results provide the means to estimate practical parameter settings that yield accurate values of (15)N transverse relaxation rates in the both CPMG experiments. 相似文献
119.
Regio- and stereo-selective synthesis of vinyl glucose ester catalyzed by an alkaline protease of Bacillus subtilis 总被引:1,自引:0,他引:1
Qi Wu Deshui Lu Ying Cai Xingtao Xue Zhichun Chen Xianfu Lin 《Biotechnology letters》2001,23(24):1981-1985
The transesterification of -d-glucose with divinylsuccinate, divinyladipate and divinylsebacate in pyridine at 55 °C for 3 days was catalyzed by an alkaline protease from Bacillus subtilis to give corresponding 6-O-vinyl glucose esters at 30%, 53% and 35% yield, respectively. The stereo-selectivity of the alkaline protease toward the -anomer was affected by the acyl donor chain length. 6-O-Vinylsuccinyl-d-glucose was mixture of - and -anomers (/=44/56), the other two products were the pure -d-glucose derivatives. 相似文献
120.
In order to assess the importance of sexual and asexual reproduction during the life history of Scirpus mariqueter, its reproductive and growth characters were concurrently examined along an elevational gradient (from low elevation to high elevation). The proportions of flowering shoot and inflorescence mass, seed : flower ratio and seed weight were used to quantify the investment in sexual reproduction. The proportions of current-year shoot and rhizome mass were used to quantify the investment in asexual reproduction, and the proportion of corm mass was used for growth, respectively. It was found that vegetative propagation predominated at low elevation, whereas sexual reproduction predominated at high elevation; and that sexual reproduction increased with declining asexual reproduction along the gradient. The results suggest that asexual reproduction is relatively favored in the early life stage, whereas sexual reproduction is favored when the population becomes mature and aged, probably because of the functional differentiation between the two reproductive types. Sexual productive characters (i.e. the proportions of flowering shoot and inflorescence mass) were negatively correlated to both growth and asexual reproductive characters along the gradient, indicating there might exist some trade-offs among growth, sexual and asexual reproduction during the life history. However, no obvious pattern was found between asexual reproductive characters and growth characters along the elevational gradient, possibly because of the varied relationships between them at different life stages. The variations in sexual and asexual reproduction in the species and the relationship between them are thought to be of great significance for local population growth, species persistence and evolution. 相似文献