Isolation of the gene encoding pilin of Bacteroides nodosus (strain 198), the causal organism of ovine footrot

The gene for pilin, the monomeric protein subunit from which the pilus of Bacteroides nodosus is constructed, has been isolated. Isolation was achieved by cloning the fragmented genome of B. nodosus in Escherichia coli RR1 using the plasmid vector pBR322. Pilin-producing colonies were identified by screening with a colony immunoassay using antiserum from a sheep immunized against purified pili from B. nodosus strain 198, and were further characterized by immunoblot analysis. Final confirmation of the presence of the pilin gene was by nucleotide sequence data which translated to the known pilin amino acid sequence.     

A conceptual review on systems biology in health and diseases: from biological networks to modern therapeutics

Human physiology is an ensemble of various biological processes spanning from intracellular molecular interactions to the whole body phenotypic response. Systems biology endures to decipher these multi-scale biological networks and bridge the link between genotype to phenotype. The structure and dynamic properties of these networks are responsible for controlling and deciding the phenotypic state of a cell. Several cells and various tissues coordinate together to generate an organ level response which further regulates the ultimate physiological state. The overall network embeds a hierarchical regulatory structure, which when unusually perturbed can lead to undesirable physiological state termed as disease. Here, we treat a disease diagnosis problem analogous to a fault diagnosis problem in engineering systems. Accordingly we review the application of engineering methodologies to address human diseases from systems biological perspective. The review highlights potential networks and modeling approaches used for analyzing human diseases. The application of such analysis is illustrated in the case of cancer and diabetes. We put forth a concept of cell-to-human framework comprising of five modules (data mining, networking, modeling, experimental and validation) for addressing human physiology and diseases based on a paradigm of system level analysis. The review overtly emphasizes on the importance of multi-scale biological networks and subsequent modeling and analysis for drug target identification and designing efficient therapies.     

Contribution of NDH-dependent cyclic electron transport around photosystem I to the generation of proton motive force in the weak mutant allele of pgr5

In angiosperms, cyclic electron transport (CET) around photosystem I (PSI) consists of two pathways, depending on PGR5/PGRL1 proteins and the chloroplast NDH complex. In single mutants defective in chloroplast NDH, photosynthetic electron transport is only slightly affected at low light intensity, but in double mutants impaired in both CET pathways photosynthesis and plant growth are severely affected. The question is whether this strong mutant phenotype observed in double mutants can be simply explained by the additive effect of defects in both CET pathways. In this study, we used the weak mutant allele of pgr5-2 for the background of double mutants to avoid possible problems caused by the secondary effects due to the strong mutant phenotype. In two double mutants, crr2-2 pgr5-2 and ndhs-1 pgr5-2, the plant growth was unaffected and linear electron transport was only slightly affected. However, NPQ induction was more severely impaired in the double mutants than in the pgr5-2 single mutant. A similar trend was observed in the size of the proton motive force. Despite the slight reduction in photosystem II parameters, PSI parameters were severely affected in the pgr5-2 single mutant, the phenotype that was further enhanced by adding the NDH defects. Despite the lack of ?pH-dependent regulation at the cytochrome b₆f complex (donor-side regulation of PSI), the plastoquinone pool was more reduced in the double mutants than in the pgr5-2 single mutants. This phenotype suggests that both PGR5/PGRL1- and NDH-dependent CET contribute to supply sufficient acceptors from PSI by balancing the ATP/NADPH production ratio.     

Comparative genomic and phenomic analysis of Clostridium difficile and Clostridium sordellii,two related pathogens with differing host tissue preference

Background

Clostridium difficile and C. sordellii are two anaerobic, spore forming, gram positive pathogens with a broad host range and the ability to cause lethal infections. Despite strong similarities between the two Clostridial strains, differences in their host tissue preference place C. difficile infections in the gastrointestinal tract and C. sordellii infections in soft tissues.

Results

In this study, to improve our understanding of C. sordellii and C. difficile virulence and pathogenesis, we have performed a comparative genomic and phenomic analysis of the two. The global phenomes of C. difficile and C. sordellii were compared using Biolog Phenotype microarrays. When compared to C. difficile, C. sordellii was found to better utilize more complex sources of carbon and nitrogen, including peptides. Phenotype microarray comparison also revealed that C. sordellii was better able to grow in acidic pH conditions. Using next generation sequencing technology, we determined the draft genome of C. sordellii strain 8483 and performed comparative genome analysis with C. difficile and other Clostridial genomes. Comparative genome analysis revealed the presence of several enzymes, including the urease gene cluster, specific to the C. sordellii genome that confer the ability of expanded peptide utilization and survival in acidic pH.

Conclusions

The identified phenotypes of C. sordellii might be important in causing wound and vaginal infections respectively. Proteins involved in the metabolic differences between C. sordellii and C. difficile should be targets for further studies aimed at understanding C. difficile and C. sordellii infection site specificity and pathogenesis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1663-5) contains supplementary material, which is available to authorized users.     

白介素-1β对高糖刺激的人肾小管上皮细胞转分化的影响

目的探讨炎症细胞因子白介素-1β（interleukin-1βIL-1β）对高糖刺激的人肾小管上皮细胞转分化的影响。-方法体外培养人肾近曲小管上皮细胞株（HKCs）,随机分为正常对照组（5.5 mmol/L normal glucose）;高糖组（30 mmol/L high glucose）;高糖＋IL-1β（5ng/ml）组。分别于处理后24h、48h、72h收集细胞,采用免疫细胞化学染色和Western蛋白印迹法检测细胞角蛋白-18（cytokeratin-18 CK-18）、α-平滑肌肌动蛋白（α-smooth muscle actinα-SMA）水平。结果高糖能够诱导肾小管上皮细胞α-SMA蛋白的合成增加,而肾小管上皮细胞的标志物CK-18的表达逐渐减少;IL-1β与高糖同时刺激可使肾小管上皮细胞α-SMA蛋白表达进一步增多,而其自身标志物CK-18的表达则明显下降。结论炎症因子IL-1β能增强高糖对肾小管上皮细胞转分化的作用。     

Phenotypic and AFLP characterization of two new pineapple somaclones derived from in vitro culture

Fifty pineapple buds (cv. Red Spanish Pinar, donor) were collected from field-grown plants and cultured in vitro. Forty-three young pineapple shoots were obtained after 42 d of implantation. Shoots were micropropagated for 168 d to produce 24,768 shoots. Three hundred young leaves were randomly selected as explants for callus formation. Calli proliferated for 4 months. Five hundred calli were randomly selected and transferred to the plantlet regeneration medium. Four hundred twenty-seven in vitro-plantlets were obtained and later hardened ex vitro. Then, 387 plantlets were transferred to the field environment and asexually propagated for two generations (30 months). Only two phenotype variants were identified: P3R5 and Dwarf. A more detailed study was carried out to compare these two variants with the donor plant. The variant P3R5 showed differences in the number of slips and suckers, and in the presence of thorns in the leaves and in the fruit crowns. The somaclonal variant Dwarf, was different from the donor plant in regard with the plant height; the peduncle diameter; the number of shoots, slips and suckers; the fruit mass with crown; the number of eyes in the fruit; the fruit height and diameter; the leaf color; the plant architecture; the length of plant generation cycle; and the fruit color and shape. Both somaclonal variants showed different AFLP banding patterns in comparison with the donor cultivar.     

In vitro activation and differentiation of naïve CD4 and CD8 T cells into HCV Core- and NS3-specific armed effector cells: A new role for CD4 T cells

Viral clearance in hepatitis C virus (HCV) infection has been correlated with strong, multi-specific and sustained T cell responses. The number of functionally active effector T cells determines the outcome of infection. Only a small number of antigen-specific naïve T cells are originally present. Upon infection, they undergo activation, clonal expansion and differentiation to become effector cells. In this study, we determined the ability of dendritic cells (DCs) to prime T cells in vitro to become effector cells upon stimulation with various TLR ligands or IFNα. T cell priming and activation was determined by proliferation and production of effector molecules, IFN-γ and Granzyme B (GrB). HCV Core-specific T cells showed significant increase in proliferation, and the number of HCV Core-specific CD4⁺ and CD8⁺ T cells producing IFN-γ and GrB was higher than control or NS3-specific T cells. These in vitro-primed CD4⁺ and CD8⁺ T cells exhibit the phenotype of just-activated and/or armed effector lymphocytes confirming the transition of naïve T cells to effector cells. This is the first study demonstrating the activation of GrB⁺CD4⁺ T cells against antigen(s) derived from HCV. Our study suggests a novel role of CD4⁺ T cells in immunity against HCV.     

基于交叉抚育的雄性根田鼠对异性同胞尿气味的识别

通过交叉抚育建立室内繁殖种群,在断奶后（80日龄）分别取这些供体的新鲜尿气味作刺激物,在行为观察箱中观察和记录雄性根田鼠对雌鼠气味的行为反应,以研究根田鼠同胞识别的化学通讯机制。结果表明：①在不同的发育时期（2～70日龄）,雄性同巢同胞与异巢同胞的体重没有显著差异。②雄性根田鼠对雌性同巢非同胞气味的接近潜伏期显著长于对异巢非同胞的接近潜伏期（P〈0．05）,其对异巢非同胞气味的访问时间和嗅舔时间都显著高于同巢非同胞气味（P〈0．05）。③雄性根田鼠对雌性异巢同胞和异巢非同胞气味的不存在明显偏好。其对两者的接近潜伏期、访问频次、访问时间、嗅舔频次和嗅舔时间等行为响应均无显著差异（P〈0．05）。这些结果表明,80日龄时,雄性根田鼠能够识别熟悉和陌生的无亲属关系雌性尿气味,但不能区分陌生的亲属和非亲属,因此,其异性同胞识别的机制为共生熟悉模式。