表达猪流行性腹泻病毒S1基因植物乳酸杆菌工程菌的免疫原性分析

为探究表达猪流行性腹泻病毒(Porcine epidemic diarrhea virus,PEDV)S1基因的植物乳杆菌工程菌是否对动物产生保护力,利用构建的含重组质粒pVE5523-S1乳杆菌口服免疫豚鼠3次,每次间隔14d,每次2×108 CFU/只.并以植物乳杆菌及含表达质粒pVE5523植物乳杆菌为阴性对照,...     

Interactomes of SARS‐CoV‐2 and human coronaviruses reveal host factors potentially affecting pathogenesis

Host–virus protein–protein interactions play key roles in the life cycle of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). We conducted a comprehensive interactome study between the virus and host cells using tandem affinity purification and proximity‐labeling strategies and identified 437 human proteins as the high‐confidence interacting proteins. Further characterization of these interactions and comparison to other large‐scale study of cellular responses to SARS‐CoV‐2 infection elucidated how distinct SARS‐CoV‐2 viral proteins participate in its life cycle. With these data mining, we discovered potential drug targets for the treatment of COVID‐19. The interactomes of two key SARS‐CoV‐2‐encoded viral proteins, NSP1 and N, were compared with the interactomes of their counterparts in other human coronaviruses. These comparisons not only revealed common host pathways these viruses manipulate for their survival, but also showed divergent protein–protein interactions that may explain differences in disease pathology. This comprehensive interactome of SARS‐CoV‐2 provides valuable resources for the understanding and treating of this disease.     

Synapses of amphids defective (SAD-A) kinase promotes glucose-stimulated insulin secretion through activation of p21-activated kinase (PAK1) in pancreatic β-Cells

The p21-activated kinase-1 (PAK1) is implicated in regulation of insulin exocytosis as an effector of Rho GTPases. PAK1 is activated by the onset of glucose-stimulated insulin secretion (GSIS) through phosphorylation of Thr-423, a major activation site by Cdc42 and Rac1. However, the kinase(s) that phosphorylates PAK1 at Thr-423 in islet β-cells remains elusive. The present studies identified SAD-A (synapses of amphids defective), a member of AMP-activated protein kinase-related kinases exclusively expressed in brain and pancreas, as a key regulator of GSIS through activation of PAK1. We show that SAD-A directly binds to PAK1 through its kinase domain. The interaction is mediated by the p21-binding domain (PBD) of PAK1 and requires both kinases in an active conformation. The binding leads to direct phosphorylation of PAK1 at Thr-423 by SAD-A, triggering the onset of GSIS from islet β-cells. Consequently, ablation of PAK1 kinase activity or depletion of PAK1 expression completely abolishes the potentiating effect of SAD-A on GSIS. Consistent with its role in regulating GSIS, overexpression of SAD-A in MIN6 islet β-cells significantly stimulated cytoskeletal remodeling, which is required for insulin exocytosis. Together, the present studies identified a critical role of SAD-A in the activation of PAK1 during the onset of insulin exocytosis.     

Batch, fed-batch and repeated fed-batch fermentation processes of the marine thraustochytrid Schizochytrium sp. for producing docosahexaenoic acid

Different fermentation processes, including batch, fed-batch and repeated fed-batch processes by Schizochytrium sp., were studied and compared for the effective DHA-rich microbial lipids production. The comparison between different fermentation processes showed that fed-batch process was a more efficient cultivation strategy than the batch process. Among the four different feeding strategies, the glucose concentration feed-back feeding strategy had achieved the highest fermentation results of final cell dry weight, total lipids content, DHA content and DHA productivity of 72.37, 48.86, 18.38 g l^?1 and 138.8 mg l^?1 h^?1, respectively. The repeated fed-batch process had the advantages of reducing the time and cost for seed culture and inoculation between each fermentation cycles. The results of fermentation characteristics and lipid characterization of the repeated fed-batch process indicated that this repeated fed-batch process had promising industrialization prospect for the production of DHA-rich microbial lipids.     

The phylogeny of leaf beetles (Chrysomelidae) inferred from mitochondrial genomes

The high-level classification of Chrysomelidae (leaf beetles) currently recognizes 12 or 13 well-established subfamilies, but the phylogenetic relationships among them remain ambiguous. Full mitochondrial genomes were newly generated for 27 taxa and combined with existing GenBank data to provide a dataset of 108 mitochondrial genomes covering all subfamilies. Phylogenetic analysis under maximum likelihood and Bayesian inference recovered the monophyly of all subfamilies, except that Timarcha was split from Chrysomelinae in some analyses. Three previously recognized major clades of Chrysomelidae were broadly supported: the ‘chrysomeline’ clade consisting of (Chrysomelinae (Galerucinae + Alticinae)); the ‘sagrine’ clade with internal relationships of ((Bruchinae + Sagrinae) + (Criocerinae + Donaciinae)), and the ‘eumolpine’ clade comprising (Spilopyrinae (Cassidinae (Eumolpinae (Cryptocephalinae + Lamprosomatinae)))). Relationships among these clades differed between data treatments and phylogenetic algorithms, and were complicated by two additional deep lineages, Timarcha and Synetinae. Various topological tests favoured the PhyloBayes software as the preferred inference method, resulting in the arrangement of (chrysomelines (eumolpines + sagrines)), with Timarcha placed as sister to the chrysomeline clade and Synetinae as a deep lineage splitting near the base. Whereas mitogenomes provide a solid framework for the phylogeny of Chrysomelidae, the basal relationships do not agree with the topology of existing molecular studies and remain one of the most difficult problems of Chrysomelidae phylogenetics.     

新疆罗布泊地区可培养嗜盐古菌多样性及其功能酶筛选

【目的】探索新疆罗布泊地区高盐环境可培养嗜盐古菌的多样性及其功能酶应用潜力。【方法】采集罗布泊地区13份土样,用纯培养并结合基于16S rRNA基因系统发育分析的方法来研究样品中嗜盐古菌的多样性。按系统进化树的聚类关系,挑选出一些菌株进行盐度耐受及淀粉酶、蛋白酶、酯酶的酶活检测。【结果】从13份土样中共分离到56株嗜盐古菌,经16S rRNA基因克隆测序,通过MEGA 4.0构建N-J树分析,56株菌分布于嗜盐古菌的10个生效发表属和5个潜在新属。运用Shannon-Wiener方法计算其多样性指数为1.820。挑选17株嗜盐古菌所测试盐浓度实验结果表明这一批嗜盐古菌的大部分生长范围在10%-35%之间,最适盐浓度在20%-25%之间。不同酶活检测结果为:淀粉酶酶活率为70.6%,蛋白酶酶活率为35.3%,酯酶酶活率为82.4%。【结论】新疆罗布泊周边地区由于气候及地理位置的独特性,蕴藏丰富的嗜盐古菌资源。本实验所设计的分离方法对嗜盐古菌的分离是极其有效的,为进一步研究新疆罗布泊及周边地区嗜盐古菌资源提供了技术基础。盐度耐受实验结果验证在低盐环境中分离嗜盐古菌新物种的可行性。同时,嗜盐古菌的酶活比率较高且活性较强为进一步开发利用嗜盐古菌资源提供了理论依据。     

Differential expression of signaling pathways in odontogenic differentiation of ectomesenchymal cells isolated from the first branchial arch

The aim of this study was to screen for differential expression of signaling pathways in odontogenic differentiation of ectomesenchymal cells isolated from the first branchial arch of embryonic day 10 (E10) mice by real time RT-PCR microarray. Observations of cellular morphology, immunocytochemistry, and RT-PCR were used to identify the cell source. A real time RT-PCR microarray was then used to detect the differential expression of signaling pathways in cells dissected from animals at two different developmental stages. These assays identified 25 up-regulated genes and 16 down-regulated genes involved in odontogenic differentiation of the ectomesenchymal cells of the first branchial arch. They represented the main members of Wnt, Hedgehog, TGF-β, NF-κB, and LDL signaling pathways. This study determined that these signaling pathways are important for odontogenic differentiation of ectomesenchymal cells of the first branchial arch.     

Acetylbritannilactone Modulates Vascular Endothelial Growth Factor Signaling and Regulates Angiogenesis in Endothelial Cells

The present study was conducted to determine the effects of 1-O-acetylbritannilactone (ABL), a compound extracted from Inula britannica L., on vascular endothelial growth factor (VEGF) signaling and angiogenesis in endothelial cells (ECs). We showed that ABL promotes VEGF-induced cell proliferation, growth, migration, and tube formation in cultured human ECs. Furthermore, the modulatory effect of ABL on VEGF-induced Akt, MAPK p42/44, and p38 phosphorylation, as well as on upstream VEGFR-2 phosphorylation, were associated with VEGF-dependent Matrigel angiogenesis in vivo. In addition, animals treated with ABL (26 mg/kg/day) recovered blood flow significantly earlier than control animals, suggesting that ABL affects ischemia-mediated angiogenesis and arteriogenesis in vivo. Finally, we demonstrated that ABL strongly reduced the levels of VEGFR-2 on the cell surface, enhanced VEGFR-2 endocytosis, which consistent with inhibited VE-cadherin, a negative regulator of VEGF signaling associated with VEGFR-2 complex formation, but did not alter VE-cadherin or VEGFR-2 expression in ECs. Our results suggest that ABL may serve as a novel therapeutic intervention for various cardiovascular diseases, including chronic ischemia, by regulating VEGF signaling and modulating angiogenesis.