Salinity controls soil microbial community structure and function in coastal estuarine wetlands

Soil salinity acts as a critical environmental filter on microbial communities, but the consequences for microbial diversity and biogeochemical processes are poorly understood. Here, we characterized soil bacterial communities and microbial functional genes in a coastal estuarine wetland ecosystem across a gradient (~5 km) ranging from oligohaline to hypersaline habitats by applying the PCR-amplified 16S rRNA (rRNA) genes sequencing and microarray-based GeoChip 5.0 respectively. Results showed that saline soils in marine intertidal and supratidal zone exhibited higher bacterial richness and Faith's phylogenetic diversity than that in the freshwater-affected habitats. The relative abundance of taxa assigned to Gammaproteobacteria, Bacteroidetes and Firmicutes was higher with increasing salinity, while those affiliated with Acidobacteria, Chloroflexi and Cyanobacteria were more prevalent in wetland soils with low salinity. The phylogenetic inferences demonstrated the deterministic role of salinity filtering on the bacterial community assembly processes. The abundance of most functional genes involved in carbon degradation and nitrogen cycling correlated negatively with salinity, except for the hzo gene, suggesting a critical role of the anammox process in tidal affected zones. Overall, the salinity filtering effect shapes the soil bacterial community composition, and soil salinity act as a critical inhibitor in the soil biogeochemical processes in estuary ecosystems.     

Regulation of lipopolysaccharide-induced inflammatory response by heat shock protein 27 in THP-1 cells

HSP27 is a member of the small HSP family which has been linked to different signaling pathways regulating critical cellular functions. But the role of HSP27 in LPS-induced inflammatory signaling pathways is still unclear. In the present study, both overexpression and RNA interference experiments indicated that HSP27 increased LPS-induced expression of iNOS and COX-2 and release of NO/PGE2 through enhancing NF-κB but not MAPK activation. The effects of HSP27 on LPS-induced iNOS/COX-2 expression and relative signaling cascade were closely related with the phosphorylation of HSP27. Further studies have shown that HSP27-regulated LPS-induced activation of NF-κB by interacting with TRAF6 and increasing the association of TRAF6-IKKγ. This could be a probable mechanism by which HSP27 modulates LPS-induce inflammatory signaling pathways. Thus, HSP27 may play a potential role in regulating inflammatory responses in immunologic system.     

Improvement of gougerotin and nikkomycin production by engineering their biosynthetic gene clusters

Nikkomycins and gougerotin are peptidyl nucleoside antibiotics with broad biological activities. The nikkomycin biosynthetic gene cluster comprises one pathway-specific regulatory gene (sanG) and 21 structural genes, whereas the gene cluster for gougerotin biosynthesis includes one putative regulatory gene, one major facilitator superfamily transporter gene, and 13 structural genes. In the present study, we introduced sanG driven by six different promoters into Streptomyces ansochromogenes TH322. Nikkomycin production was increased significantly with the highest increase in engineered strain harboring hrdB promoter-driven sanG. In the meantime, we replaced the native promoter of key structural genes in the gougerotin (gou) gene cluster with the hrdB promoters. The heterologous producer Streptomyces coelicolor M1146 harboring the modified gene cluster produced gougerotin up to 10-fold more than strains carrying the unmodified cluster. Therefore, genetic manipulations of genes involved in antibiotics biosynthesis with the constitutive hrdB promoter present a robust, easy-to-use system generally useful for the improvement of antibiotics production in Streptomyces.     

Genome-wide association study reveals the genetic architecture of 27 agronomic traits in tomato

Tomato (Solanum lycopersicum) is a highly valuable fruit crop, and yield is one of the most important agronomic traits. However, the genetic architecture underlying tomato yield-related traits has not been fully addressed. Based on ∼4.4 million single nucleotide polymorphisms obtained from 605 diverse accessions, we performed a comprehensive genome-wide association study for 27 agronomic traits in tomato. A total of 239 significant associations corresponding to 129 loci, harboring many previously reported and additional genes related to vegetative and reproductive development, were identified, and these loci explained an average of ∼8.8% of the phenotypic variance. A total of 51 loci associated with 25 traits have been under selection during tomato domestication and improvement. Furthermore, a candidate gene, Sl-ACTIVATED MALATE TRANSPORTER15, that encodes an aluminum-activated malate transporter was functionally characterized and shown to act as a pivotal regulator of leaf stomata formation, thereby affecting photosynthesis and drought resistance. This study provides valuable information for tomato genetic research and breeding.

A large-scale genome-wide association study sheds light on genetic and genomic bases underlying important yield-related traits in tomato.     

P38α/β在黑色素瘤细胞辐射应急响应中的作用

P38有丝分裂原激活蛋白激酶(MAPK)在肿瘤的发生发展中的作用仍然存在争议。实验结果显示,P38α/β特异性抑制剂SB202190可以显著增加黑色素瘤细胞的倍增时间、降低细胞的微核率,但对γH2AX foci的形成和克隆存活率并没有明显影响。提示P38α/β可能不影响人黑色素瘤细胞的DNA损伤修复能力及细胞的辐射敏感性,而是通过提高细胞的增殖速率、增加基因组不稳定性来促进人黑色素瘤细胞的恶性发展。     

Genomic organization, phylogenetic comparison and expression profiles of annexin gene family in tomato (Solanum lycopersicum)

Annexins have been suggested to play pivotal roles in stress resistance and plant development. However, related studies on fruit-bearing plants, especially on fruit development, are very limited. In the present study, we provide a comprehensive overview of the annexin family in tomato, describing the gene structure, promoter cis-regulatory elements, organ expression profile, and gene expression patterns under hormone and stress treatments. Bioinformatic analysis revealed that the nine tomato annexins were structurally different from their animal counterparts, but highly conserved annexin domains were still found in most of them. Cis-regulatory element prediction showed that there were important elements in the 2kb upstream promoter regions, including stress- and hormone-responsive-related elements. The expression patterns of these genes were investigated, and the results revealed that they were regulated under developmental processes and environmental stimuli. Among them, AnnSl1.1 and AnnSl2 were highly expressed in most of the tested organs. Genes preferentially or specifically expressed in organs, such as stigma or ovary (AnnSl6), stamen (AnnSl8), and fruit pericarp (AnnSl1.2 and AnnSl9), were identified. Some annexin genes were induced by plant hormones including abscisic acid (AnnSl3, AnnSl6, AnnSl8, and AnnSl9) and gibberellic acid (AnnSl1.1, AnnSl1.2, AnnSl4, and AnnSl7). Most of these annexin genes were induced by salt, drought, wounding, and heat or cold stresses. The present study provides significant information for understanding the diverse roles of annexins in tomato growth and development.