Potential applications of lactic acid bacteria and bacteriocins in antimycobacterial therapy

Tuberculosis(TB) is a communicable disease caused by Mycobacterium tuberculosis(M. tuberculosis). WHO estimated that 10.4 million new(incident) TB cases worldwide in year 2016. The increased prevalence of drug resistant strains and side effects associated with the current anti-tubercular drugs make the treatment options more complicated. Hence, there are necessities to identify new drug candidates to fight against various sub-populations of M. tuberculosis with less or no toxicity/side effects and shorter treatment duration. Bacteriocins produced by lactic acid bacteria(LAB) attract attention of researchers because of its "Generally recognized as safe" status. LAB and its bacteriocins possess an effective antimicrobial activity against various bacteria and fungi. Interestingly bacteriocins such as nisin and lacticin 3147 have shown antimycobacterial activity in vitro. As probiotics, LAB plays a vital role in promoting various health benefits including ability to modulate immune response against various infectious diseases. LAB and its metabolic products activate immune system and thereby limiting the M. tuberculosis pathogenesis. The protein and peptide engineering techniques paved the ways to obtain hybrid bacteriocin derivatives from the known peptide sequence of existing bacteriocin. In this review, we focus on the antimycobacterial property and immunomodulatory role of LAB and its metabolic products. Techniques for large scale synthesis of potential bacteriocin with multifunctional activity and enhanced stability are also discussed.     

CAG repeat length polymorphism in the androgen receptor gene and breast cancer risk: data on Indian women and survey from the world

We analyzed the length of the CAG repeats of the androgen receptor gene in Indian women with breast cancer, and compared the data with that of other populations across the world in an attempt to find a potential pattern of association. The study was undertaken on 1,408 individuals comprising 747 breast cancer patients and 661 control individuals recruited from three southern states of India: Andhra Pradesh, Tamil Nadu, and Karnataka. The comparison revealed no difference in mean length of the repeat between cases and controls in any of the three groups or in the analysis of pooled data. No significant difference between pre- and post-menopausal cases in any of the three groups or in the analysis of pooled data was observed. Most of the studies to date support either positive association (longer repeats--increased disease risk) or no association, and only 2 out of 20 studies reported negative association (inverse correlation between repeat length and disease risk). Comparison of these data with those from other populations revealed several interesting facts. Particularly notable is that repeat length shows association with breast cancer risk in a population-specific manner with most of the studies on American and Canadian women showing positive association, whereas those on Australian and Israeli women showing no association. Only one study had been conducted on other populations including Asians/South Asians; this restricted us from finding any patterns of association in these populations.     

Chlamydia muridarum-Specific CD4 T-Cell Clones Recognize Infected Reproductive Tract Epithelial Cells in an Interferon-Dependent Fashion

During natural infections Chlamydia trachomatis urogenital serovars replicate predominantly in the epithelial cells lining the reproductive tract. This tissue tropism poses a unique challenge to host cellar immunity and future vaccine development. In the experimental mouse model, CD4 T cells are necessary and sufficient to clear Chlamydia muridarum genital tract infections. This implies that resolution of genital tract infection depends on CD4 T-cell interactions with infected epithelial cells. However, no laboratory has shown that Chlamydia-specific CD4 T cells can recognize Chlamydia antigens presented by major histocompatibility complex class II (MHC-I) molecules on epithelial cells. In this report we show that MHC-II-restricted Chlamydia-specific CD4 T-cell clones recognize infected upper reproductive tract epithelial cells as early as 12 h postinfection. The timing of recognition and degree of T-cell activation are dependent on the interferon (IFN) milieu. Beta IFN (IFN-β) and IFN-γ have different effects on T-cell activation, with IFN-β blunting IFN-γ-induced upregulation of epithelial cell surface MHC-II and T-cell activation. Individual CD4 T-cell clones differed in their degrees of dependence on IFN-γ-regulated MHC-II for controlling Chlamydia replication in epithelial cells in vitro. We discuss our data as they relate to published studies with IFN knockout mice, proposing a straightforward interpretation of the existing literature based on CD4 T-cell interactions with the infected reproductive tract epithelium.Chlamydia trachomatis is the most common bacterial sexually transmitted infection in the developed world, with 2 to 3 million actively infected individuals in the United States (3) and similar numbers in Europe (17). In women C. trachomatis infections can ascend into the upper reproductive tract, causing pelvic inflammatory disease and scarring with resulting infertility and ectopic pregnancies.Histopathology studies show that C. trachomatis replicates predominantly in the reproductive tract epithelium during natural human infections (16, 36) and experimental murine C. muridarum infections (21). Inclusions are not seen in other cell types even though Chlamydia can undergo limited replication in macrophages and dendritic cells (33). It is unlikely that replication in non-epithelial cell lineages makes a major contribution to genital tract shedding. The mouse model for Chlamydia genital tract infections supports a critical role for CD4 T cells in protective immunity, as mice deficient in major histocompatibility complex class II (MHC-II) cannot control C. muridarum genital tract infections (22), and CD4 T-cell depletion is detrimental to resolution of primary genital tract infections (23). Because C. muridarum replicates in epithelial cells lining the reproductive tract, the most straightforward mechanism for clearing the genital tract would involve Chlamydia-specific CD4 T-cell interactions with infected epithelial cells. However in the absence of any data supporting this specific interaction, other indirect mechanisms based on CD4 T-cell production of gamma interferon (IFN-γ) and provision of help to B cells and CD8 T cells have been proposed as the mechanism for clearance (29).C. muridarum-specific CD4 T-cell lines protective in adoptive-transfer studies were shown to control C. muridarum replication in polarized epithelial monolayers (14). The mechanism of control was dependent on IFN-γ and physical interaction of T cells with the infected epithelial cells via LFA-1. In the presence of IFN-γ, T-cell engagement of epithelial cells via LFA-1 was shown to augment epithelial nitric oxide production above that induced by IFN-γ alone, and nitric oxide was shown to be the effector molecule responsible for controlling Chlamydia replication (13). This anti-Chlamydia effector mechanism did not require that the CD4 T-cell clone recognize the infected epithelial monolayer in an antigen-specific fashion, as the same preactivated CD4 T-cell clone controlled Chlamydia psittaci replication in polarized epithelial monolayers even though it does not recognize a C. psittaci antigen.Epithelial cells are semiprofessional antigen-presenting cells (APCs) and, in their unperturbed state, likely play a role in immunotolerance at mucosal surfaces (19). However in inflammatory environments, such as those resulting from transplant rejection and graft-versus-host disease, epithelial cells change their immunophenotype by upregulation of MHC-II (5, 25). In trachoma, an eye infection caused by Chlamydia trachomatis serovars A to C, conjunctival epithelial cells from human clinical specimens showed upregulated cell surface MHC-II and were presumably competent to present antigens to CD4 T cells (11, 12). In vitro studies have shown that rat and murine uterine epithelial cells process and present exogenous ovalbumin to OVA-specific CD4 T cells (28, 37). However in vitro processing and presentation of concentrated extracellular ovalbumin to CD4 T cells by uterine epithelial cells do not directly address whether Chlamydia antigens sequestered in membrane-bound inclusions get processed and presented to Chlamydia-specific CD4 T cells in vivo. The mechanics of CD4 T-cell contributions to resolution of genital tract infections remain unclear.For this study we derived an epithelial cell line from the upper reproductive tract of a female C57BL/6 mouse and a panel of 10 Chlamydia-specific CD4 T-cell clones from immune C57BL/6 mice that previously self-cleared C. muridarum genital tract infections. These reagents gave us the opportunity to directly investigate (i) whether Chlamydia-specific CD4 T cells can recognize C. muridarum-infected reproductive tract epithelial cells, (ii) when during the time course of infection recognition occurs, and (iii) the role of IFNs in modulating epithelial interactions with CD4 T cells. We present the results of those investigations here.(These data were presented in part at the 2009 Chlamydia Basic Research Conference.)     

阿萨希毛孢子菌和头状地霉菌血流感染的鉴别诊断初探

目的为临床微生物实验室建立少见类酵母样真菌血流感染诊断和鉴别诊断方法提供参考。方法采用临床资料分析,形态学检查、生化反应和分子生物学技术相结合的方法,对阿萨希毛孢子菌和头状地霉菌血流感染进行诊断和鉴别诊断。结果病例1和病例2类酵母样真菌血流感染均发生于患者白血病化疗后粒细胞缺乏期,患者病情严重,相似度高。挑取病例1、2血平皿上培养菌落进行革兰染色镜检,前者可见菌丝、关节孢子和小分生孢子,菌丝分枝分隔粗细不等,关节孢子长短不一,多呈矩形和桶型;后者可见中隔透明的菌丝断裂成关节孢子,呈长方形,不产生芽生分生孢子。API 20C AUX鉴定,提示分别为阿萨希毛孢子菌、头状地霉菌。所得序列在NCBI上进行比对,结果分别为阿萨希毛孢子菌、头状双足囊菌 头状地霉菌的有性期。结论综合应用多种技术手段有助于提高类酵母样真菌血流感染诊断的准确性。将毛孢子菌和地霉菌鉴定到种水平有利于提高临床对该类少见真菌感染的认识,合理选择抗真菌药物和改善预后。