Zeeshan Fatima
Amity Institute of Biotechnology
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Featured researches published by Zeeshan Fatima.
Microbial Pathogenesis | 2016
Moiz A. Ansari; Zeeshan Fatima; Saif Hameed
Previously we have deciphered the antifungal effect of sesamol (Ses), a phenolic compound obtained from sesame oil, against human fungal pathogen Candida albicans. To gain deeper insights into the possible mechanisms involved, transcription profiling was done in presence of Ses which revealed various targets through which Ses was barricading the growth of C. albicans. We observed that Ses perturbs membrane integrity confirming our previous observations and displayed disrupted plasma membrane ATPase activity. We further investigated that Ses leads to inhibited morphological transition, biofilm formation and epithelial cell adhesion which are significant virulence attributes required for pathogenesis. Interestingly, Ses also causes amendment in iron homeostasis as revealed by hypersensitivity under iron deprivation, ferroxidase assay to estimate iron levels and concomitant upregulation of FTR2, a high affinity iron transporter. Finally we assessed that Ses causes defect in mitochondrial functioning and DNA repair mechanism. Together, being source of consumable natural product, further studies on Ses are warranted so that it can be exploited as effective antifungal agent.
Biochemical and Biophysical Research Communications | 2018
Moiz A. Ansari; Zeeshan Fatima; Kamal Ahmad; Saif Hameed
The metabolic pathway such as glyoxylate cycle (GC) enables Candida albicans, to survive under glucose deficient conditions prevalent in the hostile niche. Thus its key enzymes (Isocitrate lyase; ICL and malate synthase; MLS) represent attractive targets against C.xa0albicans. We have previously reported the antifungal potential of a natural monoterpenoid perillyl alcohol (PA). The present study uncovers additional role of PA as a potent GC inhibitor. We explored that PA phenocopied ICL1 deletion mutant and were hypersensitive under low carbon utilizing conditions. The effect of PA on GC was substantiated by molecular docking analyses, which reveals the in-silico binding affinity of PA with ICL and MLS and explored that PA binds to the active sites of both proteins with better binding energy in comparison to their known inhibitors 3-nitropropionate and bromopyruvate respectively. Enzyme kinetics by Lineweaver-Burk plot unravels that PA inhibits ICL and MLS enzymes in competitive and non-competitive manner respectively. Moreover, semi-quantitative RT-PCR indicated that PA inhibits ICL1 and MLS1 mRNA expressions. Lastly, we demonstrated the antifungal efficacy of PA by enhanced survival of Caenorhabditis elegans model and less hemolytic activity (10.6%) on human blood cells. Further studies are warranted for PA to be considered as viable drug candidate.
The International Journal of Mycobacteriology | 2016
Sharda Sharma; Rahul Pal; Saif Hameed; Zeeshan Fatima
Objective/Background: Tuberculosis (TB) remains a global threat, claiming one-third of the population annually. The ever increasing emergence of multidrug-resistant TB (MDR-TB) is the major impediment to effective anti-TB therapy. Under such circumstances, deciphering the antimycobacterial potential of natural compounds has gained considerable prominence. This study evaluated the antimycobacterial activity of vanillin (Van), a natural food-flavoring agent and preservative, along with its potential mechanisms of action. Methods: Drug susceptibilities were performed using broth microdilution, spot, and filter-disc assays. Membrane damage was studied by nitrocefin hydrolysis and electron microscopy. Virulence attributes were assessed by biofilm formation and cell adherence. Iron availability was estimated by enzymatic (ferroxidase) assay. Results: We found that the antimycobacterial activity of Van against Mycobacterium smegmatis (a surrogate of Mycobacterium tuberculosis) is 125 μg/mL. Additionally, we observed disruption of membrane homeostasis in the presence of Van, as revealed by enhanced membrane permeability and transmission electron microscopy images showing a disturbed cell envelope. Concomitant with our findings, we also observed that Van leads to enhanced drug susceptibility to membrane targeting known anti-TB drugs. Furthermore, Van affects significant virulence traits of Mycobacterium by inhibiting biofilm formation and cell adhesion. Finally, we observed that Van disrupted iron homeostasis as displayed by hypersensitivity to iron deprivation. Conclusion: The results established for the first time that Van could be an effective antimycobacterial agent that could be exploited further in treating mycobacterial infections.
Brazilian Journal of Infectious Diseases | 2016
Rahul Pal; Saif Hameed; Sharda Sharma; Zeeshan Fatima
Novel strategies to combat the ever increasing burden of drug resistance in Mycobacterium tuberculosis (MTB) causing tuberculosis (TB) remains a global concern. The ability of MTB to sense and adapt to restricted iron conditions in the hostile environment is essential for their survival and confers the basis of their success as dreadful pathogen. The striking and clinically relevant virulence trait of MTB is its ability to form biofilms and adhere to the host cells. The present study elucidated the effect of iron deprivation on biofilm formation and cell adherence of Mycobacterium smegmatis, a non-pathogenic surrogate of MTB. Firstly, we showed that iron deprivation leads to enhanced cell sedimentation rate and altered colony morphology depicting alterations in cell surface envelope properties. We explored that biofilm formation and cell adherence to polystyrene surface as well as human oral epithelial cells were considerably reduced under iron deprivation both in presence of 2,2 BP (iron chelator) and siderophore mutant Δ011-14 strain. We further investigated that the potency of three first line anti-TB drugs (Isoniazid, Ethambutol, Rifampicin) to inhibit both biofilm formation and cell adhesion were enhanced under iron deprivation in contrast to the drugs when tested alone. Taken together, by virtue of the indispensability of iron for functional virulence traits in mycobacteria, iron deprivation strategies could be further exploited against this notorious human pathogen to explore novel drug targets.
Journal of global antimicrobial resistance | 2017
Sandeep Hans; Sharda Sharma; Saif Hameed; Zeeshan Fatima
OBJECTIVESnNovel strategies to overcome multidrug resistance (MDR) in Tuberculosis (TB) still remain a concern. Usage of natural compounds nowadays to surmount the increasing burden of MDR-TB has shown promising results. The aim of this study was to evaluate the antimycobacterial potential of sesamol (Ses) a natural phenolic compound against Mycobacterium smegmatis, a surrogate for MTB and its underlying mechanism of action along with its effect on mycobacterial virulence traits.nnnMETHODSnCell surface phenotypes were estimated microscopically and spectrophotometrically respectively. Membrane parameters were assessed using propidium iodide (PI) uptake, passive diffusion of drug with substrate EtBr and phenotypic susceptibility assay. Changes in lipid profiles were estimated by lipase assay. Oxidative and genotoxic damage were studied using fluorescent probes DCFDA and DAPI. Biofilm formation was studied using crystal violet and calcoflour white staining probes along with biomass measurement. Cell adherence was estimated using buccal epithelial cells.nnnRESULTSnWe observed that antimycobacterial activity of Ses was 6mM and it enhances the efficiency of known anti-TB drugs. Ses affects cell surface phenotypes as displayed by altered colony morphology, impaired sliding motility and enhanced cell sedimentation rate. Membrane perturbation was revealed by hypersensitivity against SDS, reduced PI uptake, enhanced passive diffusion and lipase activity. In addition, Ses leads to oxidative and DNA damage along with abrogated iron homeostasis. Furthermore, we uncover phenotypes related to virulence like inhibited biofilm formation and cell adherence to buccal epithelial cells.nnnCONCLUSIONnThis study for the first time establishes the anti-mycobacterial potential of Ses that may be further exploited for improving the therapeutic strategies and warrants further attention.
PLOS ONE | 2018
Shweta Singh; Zeeshan Fatima; Kamal Ahmad; Saif Hameed
Among the several mechanisms of multidrug resistance (MDR), overexpression of drug efflux pumps CaCdr1p and CaMdr1p belonging to ATP binding cassette (ABC) and major facilitator superfamily (MFS) respectively remain the predominant mechanisms of candidal infections. Therefore inhibiting or modulating the function of these transporters continues to draw attention as effective strategy to combat MDR. We have previously reported the antifungal potential of Geraniol (Ger), a natural monoterpenoid from Palmarosa oil, against Candida albicans. Herein, we explored the fungicidal nature of Ger. The Rhodamine 6G (R6G) and Nile red accumulation confirms the specific effect on CaCdr1p. Mechanistic insights with Candida cells overexpressing CaCdr1p and CaMdr1p revealed that Ger specifically modulates CaCdr1p activity. Kinetic studies further unraveled the competitive inhibition of Ger for R6G efflux as evident from increased apparent Km without affecting Vmax value. The effect of Ger on CaCdr1p was substantiated by molecular docking analyses, which depicted in-silico binding affinity of Ger with CaCdr1p and explored that Ger binds to the active site of CaCdr1p with higher binding energy. Although RT-PCR and western blot revealed no change in expressions of CDR1 and CaCdr1p, confocal microscopy images however depicted CaCdr1p mislocalization in presence of Ger. Interestingly, Ger was synergistic (FICI<0.5) with fluconazole (FLC) which is a well known antifungal drug. Furthermore, Ger sensitizes the FLC sensitive and resistant clinical matched pair of isolates Gu4/Gu5 and led to abrogated R6G efflux and depleted ergosterol. Furthermore, Rhodamine B labeling demonstrates altered mitochondrial potential with Ger which suggest possible linkage of dysfunctional mitochondria with CaCdr1p activity. We also estimated phenotypic virulence marker extracellular phospholipase activity which was considerably diminished along with inhibited cell adherence and biofilm biomass. Lastly, antifungal efficacy of Ger was demonstrated by enhanced survival of Caenorhabditis elegans model and negligible hemolytic activity (20%). Together, modulation of efflux pump activity by Ger and FLC synergism represent a promising approach for combinatorial treatment of candidiasis.
Journal of pathogens | 2018
Rahul Pal; Moiz A. Ansari; Venkata Saibabu; Shrayanee Das; Zeeshan Fatima; Saif Hameed
Significance of methylene blue (MB) in photodynamic therapy against microbes is well established. Previously, we have reported the antifungal potential of MB against Candida albicans. The present study attempts to identify additional antimicrobial effect of MB against another prevalent human pathogen, Mycobacterium tuberculosis (MTB). We explored that MB is efficiently inhibiting the growth of Mycobacterium at 15.62u2009μg/ml albeit in bacteriostatic manner similar to its fungistatic nature. We uncovered additional cell surface phenotypes (colony morphology and cell sedimentation rate) which were impaired only in Mycobacterium. Mechanistic insights revealed that MB causes energy dependent membrane perturbation in both C. albicans and Mycobacterium. We also confirmed that MB leads to enhanced reactive oxygen species generation in both organisms that could be reversed upon antioxidant supplementation; however, DNA damage could only be observed in Mycobacterium. We provided evidence that although biofilm formation was disrupted in both organisms, cell adherence to human epithelial cells was inhibited only in Mycobacterium. Lastly, RT-PCR results showed good correlation with the biochemical assay. Together, apart from the well-established role of MB in photodynamic therapy, this study provides insights into the distinct antimicrobial mode of actions in two significant human pathogens, Candida and Mycobacterium, which can be extrapolated to improve our understanding of finding novel therapeutic options.
Journal of pathogens | 2018
Rahul Pal; Saif Hameed; Varatharajan Sabareesh; Parveen Kumar; Sarman Singh; Zeeshan Fatima
Many of the earlier studies involving the effect of isoniazid (INH) treatment have solely focused on the fatty acyl (FA) category of Mycobacterium tuberculosis (MTB) lipids. This motivated us with the major interest to examine the impact of INH on various other categories of MTB lipids. Towards this, we chose to interpret our mass spectral data (LC-ESI-MS) by a standalone software, MS-LAMP, in which “Mtb LipidDB” was integrated. Analysis by MS-LAMP revealed that INH treatment can alter the composition of “glycerolipids (GLs)” and “glycerophospholipids (GPLs)” categories of MTB lipids, in addition to the variations to FA category. Interpretation by “MycoMass” database yielded similar results as that of Mtb LipidDB, except that significant alterations to polyketides (PKs) category also were observed. Probing biosynthetic pathways of certain key lipids belonging to any of GLs, GPLs, and PKs categories can be attractive target(s) for drug discovery or can be useful to identify means to overcome drug resistance or to obtain insights into the causal factors of virulence. To the best of our knowledge, this is the first report hinting at the influence of INH on GLs, GPLs, and PKs of MTB.
Current Drug Discovery Technologies | 2018
Shrayanee Das; Saif Hameed; Zeeshan Fatima
Tuberculosis (TB) caused by Mycobacterium tuberculosis (MTB), still remains a deadly disease worldwide. With prolonged usage of anti-TB drugs, the current therapeutic regimes are becoming ineffective, particularly due to emergence of drug resistance in MTB. Under such compelling circumstances, it is pertinent to look for new drug targets. The cell wall envelope of MTB is composed of unique lipids that are frequently targeted for anti-TB therapy. This is evident from the fact that most of the commonly used front line drugs (Isoniazid and Ethambutol) acts on lipid machinery of MTB. Thus, despite the fact that much of the attention is towards understanding the MTB lipid biology, in search for identification of new drug targets, our knowledge of bacterial cell wall non-lipid components remains rudimentary and underappreciated. Better understanding of such components of mycobacterial cell structure will help in the identification of new drug targets that can be utilized on the persistent mycobacterium. This review at a common platform summarizes some of the non-lipid cell wall components in MTB that have potential to be exploited as future drug targets.
Current Pharmacogenomics and Personalized Medicine (formerly Current Pharmacogenomics) | 2018
Venkata Saibabu; Zeeshan Fatima; Saif Hameed