Enhancing electrical outputs of the fuel cells with Geobacter sulferreducens by overexpressing nanowire proteins

Protein nanowires are critical electroactive components for electron transfer of Geobacter sulfurreducens biofilm. To determine the applicability of the nanowire proteins in improving bioelectricity production, their genes including pilA, omcZ, omcS and omcT were overexpressed in G. sulfurreducens. The voltage outputs of the constructed strains were higher than that of the control strain with the empty vector (0.470–0.578 vs. 0.355 V) in microbial fuel cells (MFCs). As a result, the power density of the constructed strains (i.e. 1.39–1.58 W m⁻²) also increased by 2.62- to 2.97-fold as compared to that of the control strain. Overexpression of nanowire proteins also improved biofilm formation on electrodes with increased protein amount and thickness of biofilms. The normalized power outputs of the constructed strains were 0.18–0.20 W g⁻¹ that increased by 74% to 93% from that of the control strain. Bioelectrochemical analyses further revealed that the biofilms and MFCs with the constructed strains had stronger electroactivity and smaller internal resistance, respectively. Collectively, these results demonstrate for the first time that overexpression of nanowire proteins increases the biomass and electroactivity of anode-attached microbial biofilms. Moreover, this study provides a new way for enhancing the electrical outputs of MFCs.     

高温强光对小麦叶绿体Deg1蛋白酶和D1蛋白的影响及水杨酸的调节作用

以小麦品种矮抗58为材料,采用0.3 mmol/L水杨酸(SA)溶液预处理灌浆期小麦叶片,以水预处理为对照,进行3种不同的光温处理:适宜温度中等光强(25℃,600 μmol m-2 s-1)2h、高温强光(38℃,1600μmol m-2 s-1)2h、高温强光2h后置于适宜温度中等光强下恢复3h.测定不同光温条件下,小麦叶绿体的Deg1蛋白酶、D1蛋白和PSⅡ功能的变化及SA的调节效应.结果表明,高温强光胁迫导致Deg1蛋白酶和D1蛋白降解,PSⅡ功能发生可逆损伤.与对照相比,水杨酸预处理不仅能够抑制高温强光下小麦叶绿体Deg1蛋白酶和D1蛋白的降解,维持较高的PSⅡ原初光化学效率(Fv/ Fm)、实际光化学效率(φPSⅡ)、电子传递速率和净光合速率(Pn),而且加快回到非逆境下PSⅡ功能的恢复.     

土壤中聚乙烯降解菌的筛选、鉴定及降解特性

[目的] 农用地膜主要成分为聚乙烯（polyethylene,PE）,因其难以被降解,其废弃物常造成“白色污染”,本研究从常年覆盖农用地膜的土壤中筛选PE降解菌,并探究其对PE制品的降解效能。[方法] 采集的土壤样品用PE为唯一碳源的无机盐培养基进行富集,筛选、纯化PE降解菌,分离菌通过形态染色、生理生化特征、16S rRNA基因序列分析进行鉴定,检测其在不同PE浓度（0%、0.05%、0.10%、0.25%、0.50%、1.00%、2.00%、3.00%）的无机盐培养基中的生长曲线,最后通过扫描电镜、光镜观察,检测分离菌对农用地膜的降解效能。[结果] 从土壤中筛选获得一株能够降解PE的分离菌株（命名为SW1）,初步鉴定其为放线菌的诺卡氏菌属Nocardia sp.。SW1的生长对PE具有明显浓度依赖,在含2% PE的无机盐培养基中生长最快,在培养的第48 h菌液浓度开始明显增加,第60 h达到最大,而在不含PE的无机盐培养基中未见生长。形态生理学观察表明,35℃培养15 d后,扫描电镜观察可见有大量菌嵌入膜内或附于膜表面生长,膜表面粗糙,并开始出现破损;培养60 d后,光镜观察可见膜大面积破损,并出现空洞。[结论] 从土壤中筛选获得了一株能够有效降解PE制品的放线菌菌株Nocardia sp. SW1。该研究丰富了PE制品降解微生物的菌种资源,为PE塑料废弃物的生物降解提供了科学数据与参考。     

Genome-wide dissection of segregation distortion using multiple inter-subspecific crosses in rice

Mendelian inheritance can ensure equal segregation of alleles from parents to offspring, which provides fundamental basis for genetics and molecular biology. Segregation distortion(SD) leads to preferential transmission of certain alleles from generation to generation. Such violation of Mendelian genetic principle is often accompanied by reproductive isolation and eventually speciation. Although SD is observed in a wide range of species from plants to animals, genome-wide dissection of such biased transmission of gametes is rare. Using nine inter-subspecific rice crosses, a genome-wide screen for SD loci is performed, which reveals 61 single-locus quantitative trait loci and 194 digenic interactions showing distorted transmission ratio, among which 24 new SD loci are identified. Biased transmission of alleles is observed in all nine crosses, suggesting that SD exists extensively in rice populations. 72.13% distorted regions are repeatedly detected in multiple populations, and the most prevalent SD hotspot that observed in eight populations is mapped to chromosome 3. Xian alleles are transmitted at higher frequencies than geng alleles in inter-subspecific crosses, which change the genetic composition of the rice populations. Epistatic interaction contributes significantly to the deviation of Mendelian segregation at the whole-genome level in rice, which is distinct from that in animals. These results provide an extensive archive for investigating the genetic basis of SD in rice, which have significant implications in understanding the reproductive isolation and formation of inter-subspecific barriers during the evolution.     

Virtual Pharmacist: A Platform for Pharmacogenomics

We present Virtual Pharmacist, a web-based platform that takes common types of high-throughput data, namely microarray SNP genotyping data, FASTQ and Variant Call Format (VCF) files as inputs, and reports potential drug responses in terms of efficacy, dosage and toxicity at one glance. Batch submission facilitates multivariate analysis or data mining of targeted groups. Individual analysis consists of a report that is readily comprehensible to patients and practioners who have basic knowledge in pharmacology, a table that summarizes variants and potential affected drug response according to the US Food and Drug Administration pharmacogenomic biomarker labeled drug list and PharmGKB, and visualization of a gene-drug-target network. Group analysis provides the distribution of the variants and potential affected drug response of a target group, a sample-gene variant count table, and a sample-drug count table. Our analysis of genomes from the 1000 Genome Project underlines the potentially differential drug responses among different human populations. Even within the same population, the findings from Watson’s genome highlight the importance of personalized medicine. Virtual Pharmacist can be accessed freely at http://www.sustc-genome.org.cn/vp or installed as a local web server. The codes and documentation are available at the GitHub repository (https://github.com/VirtualPharmacist/vp). Administrators can download the source codes to customize access settings for further development.     

A Biochemical Approach to Understand the Pathogenesis of Advanced Pulmonary Arterial Hypertension: Metabolomic Profiles of Arginine,Sphingosine-1-Phosphate,and Heme of Human Lung

Pulmonary arterial hypertension (PAH) is a vascular disease characterized by persistent precapillary pulmonary hypertension (PH), leading to progressive right heart failure and premature death. The pathological mechanisms underlying this condition remain elusive. Analysis of global metabolomics from lung tissue of patients with PAH (n = 8) and control lung tissue (n = 8) leads to a better understanding of disease progression. Using a combination of high-throughput liquid-and-gas-chromatography-based mass spectrometry, we showed unbiased metabolomic profiles of disrupted arginine pathways with increased Nitric oxide (NO) and decreased arginine. Our results also showed specific metabolic pathways and genetic profiles with increased Sphingosine-1-phosphate (S1P) metabolites as well as increased Heme metabolites with altered oxidative pathways in the advanced stage of the human PAH lung. The results suggest that PAH has specific metabolic pathways contributing to the vascular remodeling in severe pulmonary hypertension. Profiling metabolomic alterations of the PAH lung has provided a new understanding of the pathogenic mechanisms of PAH, which benefits therapeutic targeting to specific metabolic pathways involved in the progression of PAH.     

Ferritinophagy is Involved in Experimental Subarachnoid Hemorrhage-Induced Neuronal Ferroptosis

Ferroptosis is a novel form of regulated cell death involved in the pathophysiological process of experimental subarachnoid hemorrhage (SAH), but how neuronal ferroptosis occurs remains unknown. In this study, we report that SAH-induced ferroptosis is macroautophagy/autophagy dependent because the inhibition of autophagy by knocking out autophagy-related gene 5 (ATG5) apparently mitigated SAH-induced ferroptosis. We created an experimental SAH model in Sprague–Dawley rats to determine the possible mechanism. We found that SAH can trigger neuronal ferroptosis, as evidenced by the disruption of iron homeostasis, elevation of intracellular lipid peroxidation (LPO) and decreased expression of ferroptosis–protective proteins. Then, we inhibited autophagy by ATG5 gene knockout, showing that autophagy inhibition can reduce the intracellular iron level and LPO, improve the expression of ferroptosis–protective proteins, and subsequently alleviate SAH-induced cell death. Additionally, autophagy inhibition also attenuated SAH prognostic indicators, such as brain edema, blood–brain barrier permeability, and neurological deficits. These findings not only present an opinion that SAH triggers neuronal ferroptosis via activation of ferritinophagy but also indicate that regulating ferritinophagy and maintaining iron homeostasis could provide clues for the prevention of early brain injury.

     

多标记物法在心力衰竭风险评估中的应用

心力衰竭的发生发展涉及多条生理病理通路,选择不同通路中的多个生物标记物能够提高对心力衰竭风险评估的准确性。总结了心 力衰竭发生发展过程中与心肌损伤、内皮功能障碍、神经激素紊乱、炎症反应、氧化应激过程相关的生物标记物,基于多标记物评价方法 的数学模型及多标记物法在心力衰竭和药物心脏毒性风险评估中的应用。