光合细菌在微生物燃料电池中的应用研究进展

微生物燃料电池(Microbial fuel cells,MFCs)降解污染物的同时产生电能,受到广泛关注。光合细菌在MFCs领域的应用实现了污水处理、CO2捕捉、光电转换等多重功能,并显示出了良好的产电特性。本文根据光合细菌在MFCs中所起作用的不同对其产电机理进行评述,并在此基础上分析了光照对光合细菌型MFCs产电性能的影响;针对当前研究的不足与面临的问题,提出了今后光合细菌在MFCs领域的应用前景与发展方向。     

R22L天花粉蛋白的晶体结构

培养了R2 2LTCS的单晶 ,在SIEMENSX 2 0 0B面探测器系统上收集了一套 0 .1 91nm分辨率的X射线衍射数据 .数据处理用XENGEN程序系统完成 ,数据使用到 0 .2 2 0nm .用同晶差值Fourier法解析了突变体的晶体结构 ,经XPLOR程序修正得到了R2 2LTCS的分子结构 ,并找到了 6 1个水分子 ,最后R因子为 0 .1 82 ,键长和键角RMS偏差分别为 0 .0 0 1 3nm和 2 .770°.在R2 2LTCS分子中 ,与A1 6 1 ,A1 6 2主链氧成氢键的 2 2位精氨酸被亮氨酸取代后形成的空穴被水分子 2 91和 2 96所占据 ,与 2 2位Arg形成盐键相互作用的 1 6 8位Glu的侧链与TCS相比 ,转动了大约 5 0° ,羧基折向相反方向 ,并通过水分子 2 93与 1 6 5位的Lys侧链氨基桥连 .这些水参与的氢键网络部分代替了原R2 2的作用 .还讨论了二级结构间的保守氢键和盐键对活性口袋构象的影响     

mir-233 Modulates the Unfolded Protein Response in C. elegans during Pseudomonas aeruginosa Infection

The unfolded protein response (UPR), which is activated by perturbations of the endoplasmic reticulum homeostasis, has been shown to play an important role in innate immunity and inflammation. However, little is known about the molecular mechanisms underlying activation of the UPR during immune responses. Using small RNA deep sequencing and reverse genetic analysis, we show that the microRNA mir-233 is required for activation of the UPR in Caenorhabditis elegans exposed to Pseudomonas aeruginosa PA14. P. aeruginosa infection up-regulates the expression of mir-233 in a p38 MAPK-dependent manner. Quantitative proteomic analysis identifies SCA-1, a C. elegans homologue of the sarco/endoplasmic reticulum Ca²⁺-ATPase, as a target of mir-233. During P. aeruginosa PA14 infection, mir-233 represses the protein levels of SCA-1, which in turn leads to activation of the UPR. Whereas mir-233 mutants are more sensitive to P. aeruginosa infection, knockdown of sca-1 leads to enhanced resistance to the killing by P. aeruginosa. Our study indicates that microRNA-dependent pathways may have an impact on innate immunity by activating the UPR.     

Association between large artery stenosis,cerebral small vessel disease and risk of ischemic stroke

We aimed to assess the associations of large artery stenosis(LAS) and cerebral small vessel disease(CSVD) with the risk of ischemic stroke and to investigate their respective and combined contributions. In the prospective population-based Shunyi Study, 1,082 stroke-free participants aged 55.9±9.1 years were included. Participants were followed for incident stroke throughout the study period(2013–2019). Total small vessel disease score was used to measure CSVD burden. Cervico-cerebral large artery stenosis was evaluated via brain magnetic resonance angiography and carotid ultrasound. We estimated the risk of ischemic stroke in relation to LAS and CSVD with Cox regression models. During a mean follow-up of 4.2 years, 34 participants(3.1%) experienced at least one ischemic stroke. Severe LAS(≥50% stenosis versus no stenosis: HR=3.27(95% CI: 1.31–8.18))and high CSVD burden(total small vessel disease score 2–4 versus 0 point: HR=12.73(4.83–33.53)) were associated with increased stroke risk independently. In multivariate models, CSVD burden(7.72%) explained a larger portion of the variation in stroke risk than severity of LAS(3.49%). Our findings identified that both LAS and CSVD were associated with future ischemic stroke in asymptomatic subjects, while those with high CSVD burden deserve more attention in primary prevention of stroke.     

Comprehensive proteome analysis of malignant pleural effusion for lung cancer biomarker discovery by using multidimensional protein identification technology

Malignant pleural effusion (MPE) obtained from lung adenocarcinoma may contain potentially useful biomarkers for detection of lung cancer. In this study, we used a removal system for high-abundance proteins followed by one-dimensional SDS-PAGE combined with nano-LC-MS/MS to generate a comprehensive MPE proteome data set with 482 nonredundant proteins. Next, we integrated the MPE proteome and secretome data sets from three adenocarcinoma cell lines, with a view to identifying potential PE biomarkers originating from malignant cells. Four potential candidates, alpha-2-HS-glycoprotein (AHSG), angiogenin, cystatin-C, and insulin-like growth factor-binding protein 2, (IGFBP2), were isolated for preclinical validation using ELISA. Both AHSG and IGFBP2 levels were increased in lung patients with MPE (n = 68), compared to those with nonmalignant pleural effusion (n = 119). Notably, the IGFBP2 level was higher in MPE, compared with that in benign diseases (bacteria pneumonia and tuberculosis pleuritis), and significantly associated with malignancy, regardless of the cancer type. Our data additionally support an extracellular function of IGFBP2 in migration in lung cancer cells. These findings collectively suggest that the adenocarcinoma MPE proteome provides a useful data set for malignancy biomarker research.     

Emergence of scale-free leadership structure in social recommender systems

The study of the organization of social networks is important for the understanding of opinion formation, rumor spreading, and the emergence of trends and fashion. This paper reports empirical analysis of networks extracted from four leading sites with social functionality (Delicious, Flickr, Twitter and YouTube) and shows that they all display a scale-free leadership structure. To reproduce this feature, we propose an adaptive network model driven by social recommending. Artificial agent-based simulations of this model highlight a "good get richer" mechanism where users with broad interests and good judgments are likely to become popular leaders for the others. Simulations also indicate that the studied social recommendation mechanism can gradually improve the user experience by adapting to tastes of its users. Finally we outline implications for real online resource-sharing systems.     

In silico and in vitro characterization of anti-amyloidogenic activity of vitamin K3 analogues for Alzheimer's disease

Background

Aggregation of amyloid-beta (Aβ) has been proposed as the main cause of Alzheimer's disease (AD). Vitamin K deficiency has been linked to the pathogenesis of AD. Therefore, 15 synthesized vitamin K3 (VK3) analogues were studied for their anti-amyloidogenic activity.

Methods

Biological and spectroscopic assays were used to characterize the effect of VK3 analogues on amyloidogenic properties of Aβ, such as aggregation, free radical formation, and cell viability. Molecular dynamics simulation was used to calculate the binding affinity and mode of VK3 analogue binding to Aβ.

Results

Both numerical and experimental results showed that several VK3 analogues, including VK3-6, VK3-8, VK3-9, VK3-10, and VK3-224 could effectively inhibit Aβ aggregation and conformational conversion. The calculated inhibition constants were in the μM range for VK3-10, VK3-6, and VK3-9 which was similar to the IC₅₀ of curcumin. Cell viability assays indicated that VK3-9 could effectively reduce free radicals and had a protective effect on cytotoxicity induced by Aβ.

Conclusions

The results clearly demonstrated that VK3 analogues could effectively inhibit Aβ aggregation and protect cells against Aβ induced toxicity. Modified VK3 analogues can possibly be developed as effective anti-amyloidogenic drugs for the treatment of AD.

General significance

VK3 analogues effectively inhibit Aβ aggregation and are highly potent as anti-amyloidogenic drugs for therapeutic treatment of AD.     

Visualization of the structures of the hepatitis C virus replication complex

Hepatitis C viral RNA synthesis has been demonstrated to occur on a lipid raft membrane structure. Lipid raft membrane fraction purified by membrane flotation analysis was observed using transmission electron microscopy and atomic force microscopy. Particles around 0.7 um in size were found in lipid raft membrane fraction purified from hepatitis C virus (HCV) replicon but not their parental HuH7 cells. HCV NS5A protein was associated with these specialized particles. After several cycles of freezing-thawing, these particles would fuse into larger sizes up to 10 um. Knockdown of seven proteins associated with lipid raft (VAPA, COPG, RAB18, COMT, CDC42, DPP4, and KDELR2) of HCV replicon cells reduced the observed number of these particles and suppressed the HCV replication. Results in this study indicated that HCV replication complexes with associated lipid raft membrane form distinct particle structures of around 0.7 um as observed from transmission electron microscopy and atomic force microscopy.     

应用SRAP标记分析福瑞鲤及其原始亲本的遗传结构

摘要：应用SRAP分子标记对建鲤（Cyprinus carpio var. jian）、黄河鲤（C.c.haematopterus）和福瑞鲤（FFRC Strain Common Carp,C.carpio）进行遗传结构分析。结果显示,筛选出的10个多态性较好的引物组合共扩增出110个位点,其中多态性位点92个,平均多...