基于生物信息学分析从Streptomyces albofaciens JCM 4342中发现2,3-二羟基苯甲酸酯-L-丝氨酸脱水三聚体和二聚体天然产物

[背景] 铁是细菌生长的基本元素,而三价铁在自然水环境中几乎无法溶解。细菌已经进化出产生各种铁载体的能力,以促进铁的吸收。对于链霉菌,其特有的铁载体是去铁胺,同时它们也可以产生其他结构的铁载体,如ceolichelin、白霉素、肠杆菌素（enterobactin）和griseobactin。[目的] 揭示链霉菌中铁载体生物合成基因簇（Biosynthetic Gene Clusters,BGCs）的分布特点和基因簇特征,并探索其所合成铁载体的化合物结构。[方法] 利用生物信息学工具系统地分析308个具有全基因组序列信息的链霉菌中的铁载体生物合成基因簇,并用色谱和波谱方法分离和表征肠杆菌素相关天然产物。[结果] 发现Streptomyces albofaciens JCM 4342和其他少数菌株同时含有一个缺少2,3-二羟基苯甲酸（2,3-DHB）生物合成基因的孤立的肠杆菌素生物合成基因簇和另外一个推测可合成griseobactin的基因簇。从S.albofaciens JCM 4342发酵液中鉴定出4个肠杆菌素衍生的天然产物,包括链状2,3-二羟基苯甲酸酯-l-丝氨酸（2,3-DHBS）的三聚体和二聚体以及它们的脱水产物。[结论] 2个基因簇间存在一种特别的协同生物合成机制。推测是griseobactin基因簇负责合成2,3-DHB,而孤立的肠杆菌素基因簇编码的生物合成酶可夺取该底物,进而完成上述4种肠杆菌素衍生天然产物的生物合成。     

PARP1 rs1136410 C/C genotype associated with an increased risk of esophageal cancer in smokers

Molecular Biology Reports - DNA repair system plays a crucial role in maintaining genomic integrity and stability and in protecting against cancer. Poly(ADP-ribose) polymerase 1 (PARP1) functions...     

Elastin-like polypeptide and γ-zein fusions significantly increase recombinant protein accumulation in soybean seeds

Transgenic Research - Soybean seeds are an ideal host for the production of recombinant proteins because of their high content of proteins, long-term stability of seed proteins under ambient...     

非结构蛋白在非洲猪瘟病毒感染中作用

非洲猪瘟(African swine fever,ASF)是由非洲猪瘟病毒(African swine fever virus,ASFV)感染引起的一种急性、出血性猪传染病,给疫情发生国家(地区)的养猪业造成重大经济损失.ASFV为双股DNA病毒,基因组含有150～167个开放阅读框(ORFs),可编码150～200种蛋白质,其中非结构蛋白有100余种.ASFV编码的酶、转录因子、调节宿主细胞功能蛋白和病毒免疫逃逸相关蛋白等作为重要的非结构蛋白,在病毒核苷酸代谢、DNA复制、修复、转录、蛋白修饰以及病毒与宿主细胞相互作用等过程中发挥重要作用,但仍有许多非结构蛋白的功能尚不明晰.因此,本文综述了 ASFV非结构蛋白在病毒感染中的作用,以期为ASFV非结构蛋白的进一步研究提供参考.     

Flu Universal Vaccines: New Tricks on an Old Virus

Conventional influenza vaccines are based on predicting the circulating viruses year by year, conferring limited effectiveness since the antigenicity of vaccine strains does not always match the circulating viruses. This necessitates development of universal influenza vaccines that provide broader and lasting protection against pan-influenza viruses. The discovery of the highly conserved immunogens(epitopes) of influenza viruses provides attractive targets for universal vaccine design. Here we review the current understanding with broadly protective immunogens(epitopes) and discuss several important considerations to achieve the goal of universal influenza vaccines.     

A chloride efflux transporter,BIG RICE GRAIN 1, is involved in mediating grain size and salt tolerance in rice

Grain size is determined by the size and number of cells in the grain. The regulation of grain size is crucial for improving crop yield; however, the genes and molecular mechanisms that control grain size remain elusive. Here, we report that a member of the detoxification efflux carrier /Multidrug and Toxic Compound Extrusion (DTX/MATE) family transporters, BIG RICE GRAIN 1 (BIRG1), negatively influences grain size in rice (Oryza sativa L.). BIRG1 is highly expressed in reproductive organs and roots. In birg1 grain, the outer parenchyma layer cells of spikelet hulls are larger than in wild-type (WT) grains, but the cell number is unaltered. When expressed in Xenopus laevis oocytes, BIRG1 exhibits chloride efflux activity. Consistent with this role of BIRG1, the birg1 mutant shows reduced tolerance to salt stress at a toxic chloride level. Moreover, grains from birg1 plants contain a higher level of chloride than those of WT plants when grown under normal paddy field conditions, and the roots of birg1 accumulate more chloride than those of WT under saline conditions. Collectively, the data suggest that BIRG1 in rice functions as a chloride efflux transporter that is involved in mediating grain size and salt tolerance by controlling chloride homeostasis.     

Genomes of 12 fig wasps provide insights into the adaptation of pollinators to fig syconia

Figs and fig pollinators are one of the few classic textbook examples of obligate pollination mutualism. The specific dependence of fig pollinators on the relatively safe living environment with sufficient food sources in the enclosed fig syconia implies that they are vulnerable to habitat changes. However, there is still no extensive genomic evidence to reveal the evolutionary footprint of this long-term mutually beneficial symbiosis in fig pollinators. In fig syconia, there are also non-pollinator species. The non-pollinator species differ in their evolutionary and life histories from pollinators. We conducted comparative analyses on 11 newly sequenced fig wasp genomes and one previously published genome. The pollinators colonized the figs approximately 66.9 million years ago, consistent with the origin of host figs. Compared with nonpollinators, many more genes in pollinators were subject to relaxed selection. Seven genes were absent in pollinators in response to environmental stress and immune activation. Pollinators had more streamlined gene repertoires in the innate immune system, chemosensory toolbox, and detoxification system. Our results provide genomic evidence for the differentiation between pollinators and nonpollinators. The data suggest that owing to the long-term adaptation to the fig, some genes related to functions no longer required are absent in pollinators.