基因转录调控与早期三维生命体模式的构建

从分子生物学的角度而言,胚胎发育就是基因的时空调控过程,从而构建动物的三维模式.顺式调控是发育基因的基本原理;转录调控因子的激活与抑制决定了细胞分化与结构形成.     

A T7 promoter-specific, inducible protein expression system forBacillus subtilis

The adaptation and application of theEscherichia coli T7 RNA polymerase system for regulated and promoter-specific gene expression inBacillus subtilis is reported. The expression cassette used inBacillus subtilis was tightly regulated and T7 RNA polymerase (T7 RNAP) appeared 30 min after induction. The efficiency of T7 promoter-specific gene expression inB. subtilis was studied using one secretory and two cytosolic proteins of heterologous origin. The accumulation ofE. coli -galactosidase, as well as a 1,4--glucosidase fromThermoanaerobacter brockii inB. subtilis after T7 RNAP induction was strongly enhanced by rifampicin inhibition of host RNAP activity. The-amylase ofThermoactinomyces vulgaris, a secretory protein, was found to accumulate in the culture supernatant up to levels of about 70 mg/l 10–20 h after T7 RNAP induction, but was also deposited in cellular fractions. The addition of rifampicin inhibited-amylase secretion, but unexpectedly, after a short period, also prevented its further (intra)cellular accumulation     

Zn2＋参与遗传调控的研究进展

Zn^2＋在遗传调控中的作用十分广泛而显著.结合新近的研究资料,着重从染色质结构与功能、核酸的生物合成、DNA的结构及构象、基因表达的调控等四个主要方面来反映Zn^2＋与遗传调控的相关性,并阐述Zn^2＋在其中发挥作用的机理.     

RNAi knockdown of CAPAr gene affects survival and fecundity of Bemisia tabaci (Gennadius)

Bemisia tabaci (Gennadius) Asia II 1 cause significant economic losses to cotton crop, directly by feeding on sap and indirectly through virus transmission. Although the current control methods are the combination of different tactics but still the chemical control is heavily relied. B. tabaci has gained resistance to majority of the insecticides which has made it difficult to manage this pest using synthetic chemicals. RNAi based gene silencing has been evolved as potential biochemical tool for specific gene silencing of target insect-pest and has been successfully demonstrated for Hemipteran insects. Here, we report the successful silencing of the CAPAr gene in B. tabaci which encodes for the G-protein coupled receptor (a transmembrane membrane peptide). Silencing of CAPAr gene resulted into reduced survival and fecundity of B. tabaci. Oral delivery of dsRNA mediated artificial diet corresponding to CAPAr gene resulted into significantly high adult mortality of 30.74% in treatment dsCAPAr 1.0 µg/µl after 48 hr of dsRNA feeding. A significant reduction in whitefly female fecundity was recorded for all the dsCAPAr concentrations with lowest value of 53.51 eggs per female in dsCAPAr 1.0 µg/µl. The relative gene expression of CAPAr gene further confirms the down regulation of CAPAr gene in knock down adult whiteflies. Our investigation proves the importance of CAPAr for B. tabaci survival and may be exploited as potential tool which can be strategic in integrated management programme for B. tabaci.     

Drugging the undruggable proteins in cancer: A systems biology approach

In recent years, the research community has, with comprehensive systems biology approaches and related technologies, gained insight into the vast complexity of numerous cancers. These approaches allow an in-depth exploration that cannot be achieved solely using conventional low-throughput methods, which do not closely mimic the natural cellular environment. In this review, we discuss recent integrative multiple omics approaches for understanding and modulating previously identified ‘undruggable’ targets such as members of the RAS family, MYC, TP53, and various E3 ligases and deubiquitinases. We describe how these technologies have revolutionized drug discovery by overcoming an array of biological and technological challenges and how, in the future, they will be pivotal in assessing cancer states in individual patients, allowing for the prediction and application of personalized disease treatments.     

‘To be,or not to be’—The dilemma of ‘silent’ antimicrobial resistance genes in bacteria

Antimicrobial resistance is a serious threat to public health that dramatically undermines our ability to treat bacterial infections. Microorganisms exhibit resistance to different drug classes by acquiring resistance determinants through multiple mechanisms including horizontal gene transfer. The presence of drug resistance genotypes is mostly associated with corresponding phenotypic resistance against the particular antibiotic. However, bacterial communities harbouring silent antimicrobial resistance genes—genes whose presence is not associated with a corresponding resistant phenotype do exist. Under suitable conditions, the expression pattern of such genes often revert and regain resistance and could potentially lead to therapeutic failure. We often miss the presence of silent genes, since the current experimental paradigms are focused on resistant strains. Therefore, the knowledge on the prevalence, importance and mechanism of silent antibiotic resistance genes in bacterial pathogens are very limited. Silent genes, therefore, provide an additional level of complexity in the war against drug-resistant bacteria, reminding us that not only phenotypically resistant strains but also susceptible strains should be carefully investigated. In this review, we discuss the presence of silent antimicrobial resistance genes in bacteria, their relevance and their importance in public health.