Role of two-component regulatory systems in intracellular survival of Mycobacterium tuberculosis

The typical two-component regulatory systems (TCSs), consisting of response regulator and histidine kinase, play a central role in survival of pathogenic bacteria under stress conditions such as nutrient starvation, hypoxia, and nitrosative stress. A total of 11 complete paired two-component regulatory systems have been found in Mycobacterium tuberculosis, including a few isolated kinase and regulatory genes. Increasing evidence has shown that TCSs are closely associated with multiple physiological process like intracellular persistence, pathogenicity, and metabolism. This review gives the two-component signal transduction systems in M. tuberculosis and their signal transduction roles in adaption to the environment.     

链球菌病类活疫苗活菌计数参考品的研制

研制链球菌病类活疫苗活菌计数参考品,可以更加科学地评价活菌计数结果的准确性和有效性.首先,制备了 一批链球菌病类活疫苗活菌计数参考品,对其物理性状、纯粹性、真空度、剩余水分进行检验,并对其均一性、运输稳定性、热稳定性进行测定,另组织3家单位通过协作标定的方式对参考品活菌数进行赋值,用协作标定法统计参考品在12个月内的保...     

Long non-coding RNA MEG3 promotes autophagy and apoptosis of nasopharyngeal carcinoma cells via PTEN up-regulation by binding to microRNA-21

Long non-coding RNAs (lncRNAs) have been highlighted as attractive markers for diagnosis and prognosis as well as new therapeutic targets in multiple cancers, including nasopharyngeal carcinoma (NPC). Here, we attempted to investigate the underlying regulatory role of the lncRNA maternally expressed gene 3 (MEG3) in NPC development. As determined by RT-qPCR, MEG3 expression was down-regulated in NPC cells. Online RNA crosstalk analysis predicted the binding of miR-21 to MEG3 and PTEN, respectively. MEG3 was validated to bind to miR-21 while PTEN was identified as a target of miR-21 by dual-luciferase reporter gene assay. Exogenous transfection was done to change the levels of MEG3, miR-21 and PTEN in HK-1 cells to investigate their effects on the autophagy and apoptosis of NPC cells. The results suggested that MEG3 overexpression in HK-1 cells up-regulated PTEN and down-regulated miR-21, by which MEG3 further inhibited autophagy and apoptosis ability of NPC cells. The tumour formation ability was tested after injecting the HK-1 cells into nude, mice and tumour growth was monitored. Consistently, MEG3 overexpression inhibited the tumour formation in vivo. Collectively, MEG3 promotes the autophagy and apoptosis of NPC cells via enhancing PTEN expression by binding to miR-21.     

Identification of five small heat shock protein genes in Spodoptera frugiperda and expression analysis in response to different environmental stressors

Spodoptera frugiperda (J. E. Smith) is a highly adaptable polyphagous migratory pest in tropical and subtropical regions. Small heat shock proteins (sHsps) are molecular chaperones that play important roles in the adaptation to various environment stressors. The present study aimed to clarify the response mechanisms of S. frugiperda to various environmental stressors. We obtained five S. furcifera sHsp genes (SfsHsp21.3, SfsHsp20, SfsHsp20.1, SfsHsp19.3, and SfsHsp29) via cloning. The putative proteins encoded by these genes contained a typical α-crystallin domain. The expression patterns of these genes during different developmental stages, in various tissues of male and female adults, as well as in response to extreme temperatures and UV-A stress were studied via real-time quantitative polymerase chain reaction. The results showed that the expression levels of all five SfsHsp genes differed among the developmental stages as well as among the different tissues of male and female adults. The expression levels of most SfsHsp genes under extreme temperatures and UV-A-induced stress were significantly upregulated in both male and female adults. In contrast, those of SfsHsp20.1 and SfsHsp19.3 were significantly downregulated under cold stress in male adults. Therefore, the different SfsHsp genes of S. frugiperda play unique regulatory roles during development as well as in response to various environmental stressors.     

FAK contributes to proteinuria in hypercholesterolaemic rats and modulates podocyte F‐actin re‐organization via activating p38 in response to ox‐LDL

Focal adhesion kinase (FAK) is a non‐receptor protein tyrosine kinase that regulates cell adhesion, proliferation and differentiation. In the present study, a rat model of high fat diet‐induced hypercholesterolaemia was established to investigate the involvement of FAK in lipid disorder‐related kidney diseases. We showed focal fusion of podocyte foot process that occurred at as early as 4 weeks in rats consuming high fat diet, preceding the onset of proteinuria when aberrant phosphorylation of FAK was found. These abnormalities were ameliorated by dietary intervention of TAE226, a reported inhibitor of FAK. FAK is also an adaptor protein initiating cascades of intracellular signals including c‐Src, Rho GTPase and mitogen‐activated protein kinase (MAPK). P38 MAPK belongs to the latter and is centrally involved in kidney diseases. Our cell culture data revealed oxidized low‐density lipoprotein (ox‐LDL) triggered hyper‐phosphorylation of FAK and p38, ectopic expression of cellular markers (manifested as decreased WT1, podocin and NEPH1, and increased vimentin and mmp9), and re‐arrangement of F‐actin filaments with enhanced cell motility; these mutations were significantly rectified by FAK shRNA. Notably, pre‐treatment of p38 inhibitor did not alter FAK activation, albeit its deletion of p38 hyper‐activity and attenuation of cellular abnormalities, demonstrating that p38 acted as a downstream effector of FAK signalling and ox‐LDL damaged podocytes in a FAK/p38‐dependent manner. This was further identified by animal data that p38 activation was also abrogated by TAE226 treatment in hypercholesterolaemic rats, suggesting that FAK/p38 axis might also be involved in in vivo events. These findings provided a potential early mechanism of hypercholesterolaemia‐related podocyte damage and proteinuria.     

Individualism in plant populations: using stochastic differential equations to model individual neighbourhood-dependent plant growth

We study individual plant growth and size hierarchy formation in an experimental population of Arabidopsis thaliana, within an integrated analysis that explicitly accounts for size-dependent growth, size- and space-dependent competition, and environmental stochasticity. It is shown that a Gompertz-type stochastic differential equation (SDE) model, involving asymmetric competition kernels and a stochastic term which decreases with the logarithm of plant weight, efficiently describes individual plant growth, competition, and variability in the studied population. The model is evaluated within a Bayesian framework and compared to its deterministic counterpart, and to several simplified stochastic models, using distributional validation. We show that stochasticity is an important determinant of size hierarchy and that SDE models outperform the deterministic model if and only if structural components of competition (asymmetry; size- and space-dependence) are accounted for. Implications of these results are discussed in the context of plant ecology and in more general modelling situations.     

Morphogenesis and Molecular Phylogeny of a New Freshwater Ciliate,Notohymena apoaustralis n. sp. (Ciliophora,Oxytrichidae)

The live morphology, infraciliature, and morphogenesis of a new oxytrichid ciliate, Notohymena apoaustralis n. sp. collected from a freshwater pond in Qingdao (Tsingtao), China, were studied in vivo and after protargol impregnation. Notohymena apoaustralis n. sp. is characterized as follows: undulating membranes in Notohymena‐pattern; cortical granules yellow‐green, grouped around the marginal cirri and dorsal bristles, and in short irregular rows elsewhere in the cell; single contractile vacuole positioned at anterior 1/3 of the body length; two macronuclear nodules and one micronucleus; about 39 adoral membranelles; 18 frontoventral transverse cirri in typical Oxytricha‐pattern; one right and one left marginal row, almost confluent posteriorly; dorsal ciliature in typical Oxytricha‐pattern; 8–10 caudal cirri arranged in three rows, one each at the posterior end of dorsal kineties 1, 2, and 4, indistinguishable from marginal cirri in life. The morphogenetic process in N. apoaustralis n. sp. is consistent with that of the type species, Notohymena rubescens Blatterer and Foissner, 1988. Phylogenetic analyses based on small subunit rDNA sequence data suggest a sister relationship between N. apoaustralis n. sp. and Paraurostyla weissei, which cluster in a clade with Rubrioxytricha ferruginea.