Systematic truncations of chromosome 4 and their responses to antifungals in Candida albicans.

BACKGROUND: Candida albicans is an opportunistic human fungal pathogen responsible for superficial and systemic life-threatening infections. Treating these infections is challenging as many clinical isolates show increased drug resistance to antifungals. Chromosome (Chr) 4 monosomy was implicated in a fluconazole-resistant mutant. However, exposure to fluconazole adversely affects Candida cells and can generate numerous mutations. Hence, the present study aimed to truncate Chr4 and challenge the generated Candida strains to antifungals and evaluate their role in drug response. RESULTS: Herein, Chr4 was truncated in C. albicans using the telomere-mediated chromosomal truncation method. The resulting eight Candida strains carrying one truncated homolog of Chr4 were tested for response to multiple antifungals. The minimal inhibitory concentration (MIC) for these strains was determined against three classes of antifungals. The MIC values against fluconazole, amphotericin B, and caspofungin were closer to that of the wild type strain. Microdilution assay against fluconazole showed that the mutants and wild type strains had similar sensitivity to fluconazole. The disc diffusion assay against five azoles and two polyenes revealed that the zones of inhibition for all the eight strains were similar to those of the wild type. Thus, none of the generated strains showed any significant resistance to the tested antifungals. However, spot assay exhibited a reasonably high tolerance of a few generated strains with increasing concentrations of fluconazole. CONCLUSION: This analysis suggested that Chr4 aneuploidy might not underlie drug resistance but rather drug tolerance in Candida albicans.

Mechanism of streptomyces albidoflavus STV1572a derived 1-heneicosanol as an inhibitor against squalene epoxidase of Trichophyton mentagrophytes.

An increase in incidences of tinea infections paves the way to discover the novel antifungal drugs from unexplored natural resources. The quality of life in patients with tinea infection may be affected by different factors, including morbidity, length of illness, social and demographic factors. The present investigation explores the functional principle of a bioactive compound isolated from actinomycetes, S. albidoflavus STV1572a by in-silico and in-vitro studies. In continuation of our previous reports on the antidermatophytic potential of S. albidoflavus STV1572a, this study progresses with the in-silico molecular docking study of the seven GC-MS discovered ligands, and six dermatophytic modelled targets. Through virtual screening, it was revealed that a docking score -8.8 between 1-heneicosanol and squalene epoxidase favored partially in understanding the mode of action. Further validation of in-silico study was performed by a sterol quantification assay which confirmed the antidermatophytic mechanism of 1-heneicosanol. Taken together, the evidence from this study suggests that 1-heneicosanol has a potential antidermatophytic compound and can be considered for dermatophytic treatment.

Structural, molecular, functional and immunological characterization of Wuchereria bancrofti-galectin.

Galectins regulate growth and differentiation of immune cells and inflammation through their carbohydrate-binding function in humans, while also play a role in parasite survival. This study focused on the galectin of lymphatic filarial parasite Wuchereria bancrofti (Wb-Gal). The multiple sequence alignment with other galectins showed that the Wb-Gal belonged to galactoside binding lectin family, particularly tandem repeat type galectin-9. A homology model of Wb-Gal was developed in the I-TASser server using high similarity 3D structures with a quality score of 89.5. Molecular docking and dynamics studies revealed that the CCRD and NCRD of Wb-Gal bind with galactose and lactose. Further, Wb-Gal was cloned into the pET28 vector, expressed in E. coli Rosetta strain and purified by affinity chromatography. In the hemagglutination assays, the rWb-Gal bound to lactose, galactose, and glucose. Indirect Enzyme-Linked Immunosorbent Assay (ELISA) using different clinical filarial sera showed that the IgG and IgM response was against Wb-Gal x very high in all filarial clinical groups, whereas the IgA and IgG2 response was minimum to negligible. There was an enhanced response of IgG1 and IgG4 antibodies in Microfilaremics (MF) cases compared to Chronic Pathology (CP) and Endemic Normal (EN) individuals. Interestingly, the IgE response was comparatively higher in EN than MF and CP. These studies show that Wb-Gal is a member of the lectin family of proteins binding to different carbohydrates and may have an important role in the pathophysiology of filarial infection which needs to be investigated in greater detail.