The fight against leprosy has entered the crucial final phase in India, with the government's announcement of a national plan for zero transmission by 2027. Presently, leprosy has pockets of high prevalence in India and unknown transmission chains. At this juncture, we focus on essential aspects of this disease to help everyone understand the basics of the causative agent, disease prognosis, epidemiology, disease-associated societal implications and prevention strategies. Our endeavour aims to inspire novel concepts among early career researchers for combating leprosy.

Tuberculosis (TB) remains a significant global health challenge, with a massive burden in densely populated countries like India. Mycobacterium tuberculosis (Mtb), the causative agent, poses formidable treatment challenges due to its slow growth, latency, and intrinsic drug resistance mechanisms. Although conventional drugs like Isoniazid, Rifampicin, and Ethambutol have shown efficacy against mycobacteria, their prolonged treatment periods demand novel approaches to improve patient compliance and treatment outcomes. Nanoparticles (NPs) like silver nanoparticles (AgNPs) have emerged as promising drug carriers as an alternative approach for TB treatment. AgNPs hold potential as nanocarriers and antimycobacterial agents, especially when combined with rifampicin, a conventional TB drug. In this study, citrate-capped AgNPs were conjugated with rifampicin and evaluated against Mycobacterium smegmatis, a surrogate organism for MTB. The enhanced effects of AgNPs and rifampicin were investigated to enhance rifampicin's efficacy in TB treatment. We observed that prolonged conjugation between AgNPs and rifampicin may allow the nanoconjugate to penetrate bacterial cells more effectively, which in turn could help to overcome certain drug resistance mechanisms. This innovative approach offers a promising avenue for developing an improved drug delivery system for TB treatment, particularly against drug-resistant strains, where conventional therapies have limited success.

The adenylating enzymes (AEs) of the ANL family contribute to the lipid synthesis process in Mycobacterium tuberculosis (MTB). FAALs (Fatty Acyl-AMP Ligase) and FACLs (Fatty Acyl-CoA Ligase) are members of the ANL enzyme family and are closely associated with the metabolism of mycobacterial lipids responsible for successful infections. Therefore, given their role in both biosynthesis and breakdown processes within fatty acid metabolism, these two groups of proteins might be potential drug targets. The growing abundance of structural, biochemical, and genetic information on mycobacterial FAAL and FACL enzymes could provide a solid foundation for the creation of next-generation anti-tuberculosis drugs, via rational drug designing.

This is the first part of a two-part series article. Recently, we have been in the middle of a difficult time due to the Covid-19 pandemic. Pandemics or global epidemics are not new to humankind; they have occurred many times in history. The discourse of epidemiology describes mainly the causal factors which need to be mitigated to prevent or combat the effects of epidemics. In epidemiology, we are not concerned for a person, but rather every individual globally, to make life healthier for all. In this article, we will discuss the basics of epidemiological practice that scientists have used for centuries to prevent epidemics with great results. Overall, we plan for better global health aided by epidemiology.

Tuberculosis (TB) causes maximum mortality and morbidity worldwide. 25 per cent of the global population harbour Mycobacterium tuberculosis (Mtb) and therefore are at risk of developing active disease. Of late, the disseminated diseases of TB are on the increase. Nearly one-third of all TB infections can be classified as extrapulmonary-TB (EPTB). TB can spread to the bone, brain, intestine, peritoneum, genitourinary system, and female genital sites leading to problems of conception. Therefore undoubtedly, TB has turned out to be a tremendous public health problem globally. The emergence of drug-resistant bacteria calls for new anti-tuberculous drugs to enhance response to antimicrobial therapy for active TB. However, discoveries of very effective anti-TB new medicines have not materialised yet. Thus, nutritional anti-TB intervention is highly important. In the pre-antibiotic era, Vitamin D was used for the treatment of TB. Its active component 1,25-dihydroxy-vitamin D3 was shown to display anti-TB activity in vitro. Vitamin D deficient humans display greater susceptibility to TB. Vitamin D deficiency induces worse disease progression in TB cases as observed in many clinical trials. The efficacy of the addition of vitamin D supplements in TB treatment has also been estimated. Thus, by now, the role of vitamin D in TB prevention and treatment is well established. Knowledge of the molecular mechanism of vitamin D is crucially vital for new anti-TB drug design. This review article discusses the recent advancement regarding the molecular mechanism of vitamin D-related anti-TB action. Further elucidation of this area may help novel anti-TB drug development.

Mycobacterium leprae causes leprosy. M. leprae enters the body through the upper respiratory tract where it interacts with host’s cells. Interferon (IFN) is a class of cytokines in human body that are released in case of viral and intracellular pathogen infection and they activate the immune cells to eradicate those pathogens. IFN-γ (Type-II IFN) confers immunity against bacterial, viral, and protozoan diseases. Loss of function mutations in IFN-γ results in poor immunity towards mildly virulent mycobacterium. Upon M. leprae invasion, monocytes enter the site of infection and differentiates into macrophages. IFN-γ induces endothelial cells (EC) of the pathogenic micro-environment to cause monocyte differentiation into pro-inflammatory M1 macrophages for immediate antimicrobial activity. This differentiation is ceased in the absence of endothelial cells. M1 macrophages are clinically more active than anti-inflammatory M2 macrophages induced by resting EC. The former produced higher amounts of pro-inflammatory cytokines in response to the TLR2/1 ligand of M. leprae. The former also showed elevation of vitamin D-associated antimicrobial pathway genes, which are required to counter M. leprae. In addition, the former accumulates less oxidised LDL to prevent growth of M. leprae. Thus, advancement of IFN-γ research would help in the design of next-generation anti- leprosy therapeutics.

Female genital tuberculosis (GTB) contributes significantly to infertility in low- and middle-income countries. Dissemination of infection from pulmonary and extrapulmonary sites is the major reason for causation of GTB. Additionally, sexual transmission of GTB from male partners has been reported. We selected 81 couples desiring babies from an in vitro fertilization clinic. We used multiplex-PCR for mycobacterial detection in semen of males, in the endometrium of their female counterparts and in the products of conception (POC) from miscarriage. Data interpretation shows that these pregnancies failed owing to sexual transmission of mycobacteria. We noticed by multiplex PCR that mycobacterial infestation in the female can take place in either endometrium or POC from asymptomatic males harbouring mycobacteria in their semen. Therefore, we propose sexual transfer of mycobacteria to be a probable cause of miscarriage. Thus, we suggest multiplex PCR based screening of semen for all males of the couples attempting successful childbirth.

Tuberculosis (TB) is one of the leading causes of death from an infectious disease worldwide. India remains to be the country carrying highest burden of the disease. One of the potent problems of present days, in this field, is the emergence of Multi-Drug-Resistant Tuberculosis (MDR-TB). MDR is defined as resistance to isoniazid (INH) and rifampin (RIF). The spread of MDR-TB is one of the biggest challenges to global public health system. Thus, detection of MDR-TB strains is critically important for containment of global TB epidemics. In this study, we are determining the MDR incidence rate in the West Bengal state of India, which is one of the most TB prone areas of the world. The RIF-resistant mutations of Mycobacterium tuberculosis (MTB) were shown to map in the rpoB locus and INH-resistant mutations of MTB were shown to map in inhA and katG loci. Therefore, in the present study, we have detected MDR-TB strains by mapping rpoB, katG & inhA mutations. Our Line Probe Assay (LPA) based results from a vast pool of MTB organisms (carrying 3653 bonafide sputum positive patient isolates) indicated the presence of 14.37% MDR isolates which matches in general with the previously reported results from various parts of the world (approx. 12-16%). Therefore, we conclude that our MDR rate is generally comparable to that of the other investigations performed in the rest of the world. We also found that the male patients are more likely to contract the MDR strains than the female patients (1.97:1.0). This data also conforms to the global statistics.

Drug resistance in tuberculosis (TB) is a global problem and both developed as well as under developed parts of the world are predisposed to drug resistant TB. Multiple drug resistant–TB (MDR-TB) designates the very strain of the pathogen which is resistant to at least two primary anti-TB drugs isoniazid and rifampicin. This strain after acquiring a further bacillary resistance to any second line injectable drug and any of the fluoroquinolones is termed as extensively drug resistant TB (XDR-TB). The present review is endeavored to recapitulate the contemporary state of multidrug resistance in TB, the pathophysiology and recent developments for a rapid and reliable detection of the infection and management of MDR-TB. The challenge of MDR-TB management must be embarked on by skilled doctors at operational BCL-3 laboratory facilities where all allied services for the in-vitro sensitivity testing of mycobacteria are available because it includes extended treatment with costly second–line drugs containing meticulous toxicity. Even more dreaded are some newly emerging TB strains namely XDR-TB which is resistant to many more anti-TB agents (such as isonicotinic acid hydrazide and rifampicin plus second line injectable streptomycin, amikacin and kanamycin). Newer discovery of novel anti-TB drugs through recent research regarding the management of drug resistant tuberculosis would help avert and eradicate MDR-TB as well as XDR-TB. For shortening of the TB–treatment regimen, a few drugs, especially gatifloxacin and moxifloxacin, are being tested, while PA-824, OPC-67683 and TMC-207 are also being studied for both drug resistant and drug susceptible disease. Given the past global trends in MDR-TB, if aggressive preventive and management strategies are not implemented against it, XDR-TB would emerge to a larger extent which would severely cripple global control efforts of TB. However, very recently a newly discovered drug bedoquinoline is demonstrating strong promise towards containment of XDR-TB.

Cancer-derived heat shock protein gp96 induces a tumor-specific protective immune response primarily mediated by cytotoxic T lymphocytes (CTL) directed toward cancer-associated peptides associated with gp96. Both innate and adaptive immune responses have been demonstrated using a cell culture-based signaling mechanism. When used as an extraneous vaccine, one critical interaction which must occur for an immune response to be generated is the interaction between gp96 and the antigen presenting cell (APC) surface receptors (CD91, SR-A, TLR-2, and TLR-4). Our previous study concluded that gp96 purified from various rat and human prostate cancers is differentially glycosylated based on the amino and neutral monosaccharide content, and it was postulated that the monosaccharides may play a role in its biological activity. In this report, we report differences in the cancer-specific sialic acid content of gp96 purified from normal rat prostate compared to two rat prostate cancers, MAT-LyLu and Dunning G, as well as between two human prostate cancer cells, LnCaP and DU145. We also examined the modulatory effect of sialic acid residues on the binding of gp96 to APCs and its subsequent activation. Our results supported the contention that significant differences in the sialic acid content exist between Dunning G, MAT-LyLu, and normal rat prostate gp96, which affected its binding and biochemical activity to APCs. We therefore postulate that varied glycans of HPS96, a hitherto neglected structural component, may play a pivotal role in its anticancer activity. We suggest that construction of the glycan tree is a key to identification of the necessary and sufficient elements in the structure-function activity of HSP96.

4780 Autologous HSP96 is being evaluated as a multivalent peptide cancer vaccine. The ability of HSP96 to act as a peptide chaperone forms the basis for its use as a multivalent biological cancer vaccine. Internalization of HSP96/peptide complex occurs through cell surface receptors, such as CD91 resulting in cross presentation of cancer specific antigenic peptides and elicitation of tumor specific cytotoxic T lymphocytes (CTLs). HSP96 is a glycoprotein containing two known N-linked glycan structures and four more potential N-linked glycosylation sites. However, the role of these glycosyl moieties, if any, on the structure and function of HSP96 is currently unknown. We discovered that purified HSP96, from various human and rat prostate tumors have significant differences in glycosylation patterns which is correlated with cell specific phenotype and removal of glycosyl moieties modulates peptide binding affinity. We demonstrated these effects using glycosylated and unglycosylated purified HSP96 and VSV-8 peptide (RGYVYQGL). These results for the first time implicate glycans as signatorial elements of tissue derived HSP96 that modulate its peptide chaperoning and binding ability. Other functions of HSP96 such as the integral ATPase activity and cell surface receptor mediated endocytosis may also be dependent on glycan structures. These studies are intended to define the structural components that determine the pleomorphic functions of HSP96 based cancer vaccines.

Heat shock protein gp96 induces a tumor-specific protective immunity in a variety of experimental tumor models. Because the primary sequences of the glycoprotein, gp96 are identical between tumor and normal tissues, the peptides associated with gp96 and/or the posttranslational modifications of gp96, determine its immunogenicity. Gp96-associated peptides constitute the antigenic repertoire of the source tissue; thus, purified gp96-peptide complexes have clinical significance as autologous cancer vaccines. However, the role of altered glycosylation and its contribution in the biological as well as immunologic activity of gp96 still remains uncharacterized. We examined the cancer-specific glycosylation patterns of gp96. To this end, monosaccharide compositions of gp96 were compared between normal rat prostate and two cancerous rat prostate tissues, nonmetastatic/androgen-dependent Dunning G and metastatic/androgen-independent MAT-LyLu, as well as two human nonmetastatic prostate cancer cell lines, androgen-dependent LnCaP and androgen-independent DU145. Marked differences were observed between the gp96 monosaccharide compositions of the normal and cancerous tissues. Furthermore, gp96 molecules from more aggressive cellular transformations were found to carry decreasing quantities of several monosaccharides as well as sum total content of neutral and amino sugars. We believe that the unique glycosylation patterns contribute to cellular phenotype and that the posttranslational modifications of gp96 may affect its functional attributes.

A Neisseria gonorrhoeae (gonococcus, GC) pilin glycosylation gene, pgtA, can either possess or lack phase-variation ability. Many GC, particularly the disseminated strains, carry a phase-variable pgtA. However, other GC, predominantly the uncomplicated gonorrhea isolates, carry a pgtA lacking phase-variability. These and other results suggest GC pilin glycan's pathogenic involvement.

Biotechnology, a multidisciplinary science, has many applications. A major application in chemical and pharmaceutical industries involves the use of enzymes, mostly from microbial sources, in the production process of many useful products. Various compounds including many proteins and enzymes are produced through microbial fermentation. Filamentous fungi, with their many virtues and long history of industrial use, have lately become targets for gene manipulation for producing strains with improved yield and better expression-secretion system for homologous and heterologous eukaryotic gene products. To genetically modify filamentous fungi for enhanced expression of a desired gene and secretion of its product, it requires a suitably designed gene-construct with correctly chosen and aligned sequences of the gene of interest and its controlling elements, as well as an efficient gene-transfer system for transforming the host fungus. An important feature of the transformation of filamentous fungi is that the transforming DNA stably integrates into the host genome. Substantial research for understanding the molecular aspects of filamentous fungal expression systems is necessary for its biotechnological application in an industrial context.

The pilus of pathogenic Neisseria is a polymer composed mainly of the glycoprotein, pilin. Recent investigations significantly enhanced characterization of pilin glycan (Pg) from N. gonorrhoeae (gonococcus, GC) and N. meningitidis (meningococcus, MC). Several pilin glycosylation genes were discovered recently from these bacteria and some of these genes transfer sugars previously unknown to be present in neisserial pili. Due to these findings, glycans of GC and MC pilin are now considered more complex. Furthermore, various Pg can be expressed by different strains and variants of GC, as well as MC. Intra-species variation of Pg between different groups of GC or MC can partly be due to polymorphisms of glycosylation genes. In pilus of pathogenic Neisseria, alternative glycoforms are also produced due to phase-variation (Pv) of pilin glycosylation genes. Most remarkably, the pgtA (pilin glycosyl transferase A) gene of GC can either posses or lack the ability of Pv. Many GC strains carry the phase-variable (Pv+) pgtA, whereas others carry the allele lacking Pv (Pv–). Mostly, the GC isolates from disseminated gonococcal infection (DGI) carry Pv+ pgtA but organisms from uncomplicated gonorrhea (UG) contain the Pv– allele. This data suggests that Pv of pgtA facilitates DGI, whereas constitutive expression of the Pv– pgtA may promote UG. Additional implications of Pg in various physiological and pathogenic mechanisms of Neisseria can also be envisaged based on various recent data.

The pilin glycoprotein (PilE) is the main building block of the pilus of Neisseria gonorrhoeae (gonococcus [GC]). GC pilin is known to carry a disaccharide O-glycan, which has an alphaGal attached to the O-linked GlcNAc by a 1-3 glycosidic bond. In this report, we describe the cloning and characterization of the GC gene, pilus glycosyl transferase A (pgtA), which encodes the galactosyl transferase that catalyzes the synthesis of this Gal-GlcNAc bond of pilin glycan. A homopolymeric tract of Gs (poly-G) is present in the pgtA gene of many GC strains, and this pgtA with poly-G can undergo phase variation (Pv). However, in many other GC, pgtA lacks the poly-G and is expressed constitutively without Pv. Furthermore, by screening a large number of clinical isolates, a significant correlation was observed between the presence of poly-G in pgtA and the dissemination of GC infection. Poly-G was found in pgtA in all (24 out of 24) of the isolates from patients with disseminated gonococcal infection (DGI). In contrast, for the vast majority (20 out of 28) of GC isolated from uncomplicated gonorrhea (UG) patients, pgtA lacked the poly-G. These results indicate that Pv of pgtA is likely to be involved in the conversion of UG to DGI.

The genes encoding the glycosyltransferases responsible for the addition of the five sugars in the alpha -oligosaccharide (alpha -OS) moiety of lipooligosaccharide (LOS) have been identified. Disruption of these glycosyltransferase genes singly or in combination results in corresponding truncations in LOS. In the present work we show that sequential deletion of the terminal four sugar residues of gonococcal alpha -OS had no discernible effect on the invasion of human conjunctival, endometrial, and cervical cell lines. However, deletion of the proximal glucose, which resulted in the complete deletion of alpha -OS, significantly impaired invasion of the gonococci into all three cell lines. The effect of deleting alpha -OS on invasion was independent of and additive to the known invasion-promoting factor OpaA. These data suggest that the proximal glucose residue of the alpha -OS chain of LOS is required for efficient invasion of gonococci into host mucosa.