Basic Fibroblast Growth Factor Expression is Implicated in Mesenchymal Stem Cells Response to Light-Induced Retinal Injury

Neurotrophic factors are involved in neuroprotection and its expression in mesenchymal stem cells (MSCs) may change during light-induced retinal injury. In this study, neurotrophic factor expression in MSCs was investigated after stimulation by supernatants of homogenized retina (SHR) from normal and light-injured rats. Conditioned media from control MSCs (CM-MSCs), MSCs stimulated by normal SHR (CM-NSHR), and MSCs stimulated by light-injured SHR (CM-ISHR) were examined regarding their ability to prevent degeneration of retinal explants. Basic fibroblast growth factor (bFGF) in MSCs was knockdown by lentivirus-mediated mRNA interference. Transfected MSCs were stimulated by SHR, and retinal preservation was reevaluated in the resultant conditioned media. We detected significant up-regulation of bFGF in CM-ISHR, accompanied by superior retinal neurotrophic effects in CM-ISHR over CM-NSHR and CM-MSCs. Down-regulation of bFGF in MSCs effectively inhibited this protective effect. Adding neutralizing antibody against bFGF to CM-ISHR also induced a similar effect. It is thus concluded that retinal injury may enhance neurotrophic factor expression in MSCs and promote the repair process. bFGF may play a critical role in MSCs’ response to retinal injury.     

新疆伊犁河不同河段鱼类的物种多样性和优势种

为了了解伊犁河鱼类群落结构和多样性特征, 于2012—2014年连续3年对我国境内新疆伊犁河上、中和下游不同河段进行鱼类资源调查。获得27种鱼类样本, 隶属于6目9科23属。伊犁河中、上游河段主要以斯氏高原鳅、新疆裸重唇鱼、新疆高原鳅和伊犁裂腹鱼等土著鱼类为优势种, 下游河段的优势种主要有鲤、草鱼和鲫等外来种。伊犁河中、上游河段鱼类种类稀少, 大中型鱼类资源稀少, 鱼类群落多样性低。梯级水电站的开发、过度捕捞以及外来种入侵对伊犁河鱼类鱼类群落造成了很大的影响。     

丝状真菌Amorphotheca resinae ZN1的糠醛降解代谢分析

木质纤维素在预处理过程产生的降解产物对后续的酶水解和微生物发酵过程产生了强烈的抑制。因此,这些抑制物的脱除即所谓的"脱毒"步骤是正常进行后续酶解和发酵的前提条件。我们对本实验室筛选的丝状真菌Amorphotheca resinae ZN1的糠醛的代谢路径进行了研究。丝状真菌A.resinae ZN1转化糠醛的降解代谢途径可以简述为:糠醛首先快速地转化为毒性较低的糠醇;在有氧条件下,糠醇又再度生成不致对微生物产生危害的低浓度糠醛,糠醛继续氧化为糠酸。推测糠酸可能继续进入TCA循环,进而完成糠醛的完全降解。研究结果为将来加快丝状真菌A.resinae ZN1生物脱毒速率、改善木质纤维素生物转化的限速步骤提供了重要的实验依据。     

啤酒抗日光嗅味的研究

啤酒中的３－甲基－２－丁烯－１－硫醇是由光照产生的。减少光照或减少其胶驱物质的产生是降低啤酒日光嗅味的有效途径。酵母和核黄素在ＭＢＴ的形成过程中起到关键作用同,还原酒花苦味物质能从根本上解决啤酒的日光嗅味。     

多肽抗体检测原发性肝癌血清标志物ELISA方法的建立及应用

血清多肽是癌症诊断信息的重要来源,建立、优化了检测多肽标志物的直接ELISA法,并应用于肝癌血清中的多肽标志物的检测。制备及纯化针对多肽标志物Pep5的单克隆抗体并进行辣根过氧化物酶标记,用其建立检测相应抗原的直接ELISA法。方法线性范围为1.5-20 ng/mL,检测限为1.24 ng/mL;标准品批内及批间CV分别小于3.66%及4.89%,血清样本批内及批间CV分别小于11.69%及18.18%;线性范围内(9、12和15 ng/mL)的回收率分别为98.98%,99.61%和101.58%。应用该方法共检测160例正常血清、104例肝硬化及156例肝癌患者血清,正常组与肝硬化组及肝癌组间差异显著(P<0.001),Pep5诊断肝癌的敏感性和特异性分别为80.8%和96.2%。同时检测94例HCC血清中的AFP和Pep5,AFP检出率为63.8%,Pep5检出率为90.4%,AFP联合Pep5检测时,能将HCC的检出率提高至94.7%。     

荧光定量RT-PCR检测血管内皮细胞PAI-1 mRNA方法的建立

为了建立用荧光定量PCR检测人微血管内皮细胞纤溶酶原激活剂抑制物-1（PAI-1）mRNA表达的方法。提取人微血管内皮细总RNA,经RT-PCR获得靶基因（PAI-1）及管家基因（β-actin）的PCR产物。纯化后,作为标准品梯度稀释,采用SYBR Green I定量PCR检测,建立标准曲线。方法学考核参数为特异性、线性范围、灵敏性和重复性。分析全反式维甲酸对内皮细胞表达PAI-1 mRNA的干预效果。这种定量方法特异性好,检测的灵敏度达10^3拷贝,线性范围为10^4-10^10拷贝,循环阈值与PCR体系中起始模板量的对数值之间有着良好的线性关系（r^2〉0.990）,批内变异≤4.93%,批间变异≤9.12%。全反式维甲酸能上调内皮细胞PAI-1 mRNA的表达,且呈剂量依赖性。因此,荧光定量RT-PCR检测血管内皮细胞PAI-1基因表达的方法有助于溶栓药物药理学的研究和新药筛选。     

工业微生物中NADH的代谢调控

NADH是微生物代谢网络中的一种关键辅因子。调节微生物胞内NADH的形式与浓度是定向改变和优化微生物细胞代谢功能, 实现代谢流最大化、快速化地导向目标代谢产物的重要手段之一。以下在详尽总结了NADH生理功能的基础上, 从生化工程(添加外源电子受体、不同氧化还原态底物及NAD合成前体物, 调节培养环境和氧化还原电势)和代谢工程(过量表达NADH代谢相关酶、缺失NADH竞争途径及引入NADH外源代谢途径)两方面分析、归纳了NADH代谢调控策略, 进而凝练出调控NADH/NAD+比率调节微生物细胞代谢功能研究方面亟待解决的3个科学问题及可能的解决途径。     

HIF-1α acts downstream of TNF-α to inhibit vasodilator-stimulated phosphoprotein expression and modulates the adhesion and proliferation of breast cancer cells

Metastasis is the leading cause of death in breast cancer patients. Recent evidence suggests that inflammation-related cytokine tumor necrosis factor-alpha (TNF-α) is implicated in tumor invasion and metastasis, but the mechanism of its involvement remains elusive. In this study, we employed MCF-7 breast cancer cells as an experimental model to demonstrate that TNF-α inhibits breast cancer cell adhesion and cell proliferation through hypoxia inducible factor-1alpha (HIF-1α) mediated suppression of vasodilator-stimulated phosphoprotein (VASP). We observed that TNF-α treatment attenuated the adhesion and proliferation of MCF-7 cells it also dramatically increased HIF-1α expression and decreased VASP expression. Through a variety of approaches, including promoter assay, electrophoretic mobility shift assay (EMSA), and chromatin immunoprecipitation (ChIP), we identified VASP as a direct target gene of HIF-1α. In addition, we confirmed that HIF-1α mediated the repression of VASP expression by TNF-α in MCF-7 cells. We also demonstrated that exogenous VASP expression or knockdown of HIF-1α relieved TNF-α induced inhibition of cell adhesion and proliferation. We identified a novel TNF-α/HIF-1α/VASP axis in which HIF-1α acts downstream of TNF-α to inhibit VASP expression and modulate the adhesion and proliferation of breast cancer cells. These data provide new insight into the potential anti-tumor effects of TNF-α.     

利用三阶段葡萄糖添加策略减少乙酸合成并促进重组大肠杆菌生产L-苯丙氨酸

为了降低副产物乙酸的积累和提高L-苯丙氨酸的产量,分别优化了L-苯丙氨酸发酵的初始葡萄糖浓度和葡萄糖的指数流加策略.结果表明,20 g/L的初始葡萄糖浓度可以控制细胞的比生长速率低于临界值0.3 h-1,显著地降低了乙酸的积累,提高了L-苯丙氨酸的产量.采用预设比生长速率μ3* =0.4(h-1)进行葡萄糖的指数流加取得了实际最大比生长速率0.29 h-1,使细胞的比生长速率低于临界值,促进了L-苯丙氨酸的合成,最终获得L-苯丙氨酸的产量达48.45 g/L,比本实验室原有水平提高了37％.     

Protein-protein interaction site predictions with three-dimensional probability distributions of interacting atoms on protein surfaces

Protein-protein interactions are key to many biological processes. Computational methodologies devised to predict protein-protein interaction (PPI) sites on protein surfaces are important tools in providing insights into the biological functions of proteins and in developing therapeutics targeting the protein-protein interaction sites. One of the general features of PPI sites is that the core regions from the two interacting protein surfaces are complementary to each other, similar to the interior of proteins in packing density and in the physicochemical nature of the amino acid composition. In this work, we simulated the physicochemical complementarities by constructing three-dimensional probability density maps of non-covalent interacting atoms on the protein surfaces. The interacting probabilities were derived from the interior of known structures. Machine learning algorithms were applied to learn the characteristic patterns of the probability density maps specific to the PPI sites. The trained predictors for PPI sites were cross-validated with the training cases (consisting of 432 proteins) and were tested on an independent dataset (consisting of 142 proteins). The residue-based Matthews correlation coefficient for the independent test set was 0.423; the accuracy, precision, sensitivity, specificity were 0.753, 0.519, 0.677, and 0.779 respectively. The benchmark results indicate that the optimized machine learning models are among the best predictors in identifying PPI sites on protein surfaces. In particular, the PPI site prediction accuracy increases with increasing size of the PPI site and with increasing hydrophobicity in amino acid composition of the PPI interface; the core interface regions are more likely to be recognized with high prediction confidence. The results indicate that the physicochemical complementarity patterns on protein surfaces are important determinants in PPIs, and a substantial portion of the PPI sites can be predicted correctly with the physicochemical complementarity features based on the non-covalent interaction data derived from protein interiors.