dMycobacterium tuberculosis expresses the 28-kDa protein HupB (Rv2986c) and the Fe 3؉ -specific high-affinity siderophores mycobactin and carboxymycobactin upon iron limitation. The objective of this study was to understand the functional role of HupB in iron acquisition. A hupB mutant strain of M. tuberculosis, subjected to growth in low-iron medium (0.02 g Fe ml ؊1 ), showed a marked reduction of both siderophores with low transcript levels of the mbt genes encoding the MB biosynthetic machinery. Complementation of the mutant strain with hupB restored siderophore production to levels comparable to that of the wild type. We demonstrated the binding of HupB to the mbtB promoter by both electrophoretic mobility shift assays and DNA footprinting. The latter revealed the HupB binding site to be a 10-bp AT-rich region. While negative regulation of the mbt machinery by IdeR is known, this is the first report of positive regulation of the mbt operon by HupB. Interestingly, the mutant strain failed to survive inside macrophages, suggesting that HupB plays an important role in vivo.

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DD-Carboxypeptidases (DD-CPases) are low-molecular-mass (LMM) penicillin-binding proteins (PBPs) that are mainly involved in peptidoglycan remodelling, but little is known about the DD-CPases of mycobacteria. In this study, a putative DD-CPase of Mycobacterium smegmatis, MSMEG_2433 is characterized. The gene for the membrane-bound form of MSMEG_2433 was cloned and expressed in Escherichia coli in its active form, as revealed by its ability to bind to the Bocillin-FL (fluorescent penicillin). Interestingly, in vivo expression of MSMEG_2433 could restore the cell shape oddities of the septuple PBP mutant of E. coli, which was a prominent physiological characteristic of DD-CPases. Moreover, expression of MSMEG_2433 in trans elevated beta-lactam resistance in PBP deletion mutants (DdacAdacC) of E. coli, strengthening its physiology as a DD-CPase. To confirm the biochemical reason behind such physiological behaviours, a soluble form of MSMEG_2433 (sMSMEG_2433) was created, expressed and purified. In agreement with the observed physiological phenomena, sMSMEG_2433 exhibited DD-CPase activity against artificial and peptidoglycan-mimetic DD-CPase substrates. To our surprise, enzymic analyses of MSMEG_2433 revealed efficient deacylation for beta-lactam substrates at physiological pH, which is a unique characteristic of beta-lactamases. In addition to the MSMEG_2433 active site that favours DD-CPase activity, in silico analyses also predicted the presence of an omega-loop-like region in MSMEG_2433, which is an important determinant of its beta-lactamase activity. Based on the in vitro, in vivo and in silico studies, we conclude that MSMEG_2433 is a dual enzyme, possessing both DD-CPase and beta-lactamase activities.

Though nonscalpel vasectomy (NSV) technique was introduced in India in 1992 to increase male participation in family planning, it has failed to get adequate momentum and to achieve its goal. We conducted a cross-sectional questionnaire-based survey to get insight into apathy of men towards NSV. The study included 428 respondents. Most of the respondents (97.4%) were aware of NSV as a method for permanent male sterilization. The majority of them (97.2%) knew that NSV is done without any charge and cash incentive is given to the NSV client after the procedure. Though 68.0% respondents agreed that permanent sterilization is a possible option for them, only 34.1% respondents were willing to adopt NSV as a method of family planning. Fear of surgical procedure (40.7%), permanent nature of procedure (22.2%), and religious belief (19.0%) were the common reasons for unwillingness to adopt NSV. We conclude that there is a need to design and develop need-based information, education and communication (IEC) strategy to bridge the existing information gap among the eligible couples regarding NSV to improve its adoption. Involvement of community leaders and satisfied clients and utilization of television and radio would enhance the effectiveness of such interventions.