Sourabh Dwivedi

This is a paper I wrote for a course work and hence it is not very elaborate but I have tried for arguing and developing an insight on a post-modernist phenomenon called "Tourism". Though I develop a critique of the touristic experience but my aim is to locate culturally a common individual in the neo-liberal society. The conclusion of this paper is short due to limitations but there is a lot that could be said once the crux of the arguments is understood. I leave it to the readers to understand where they belong in this discourse.

The DNA damaging and anti-mutagenic activities of the aqueous (Aq) and dimethyl sulfoxide (DMSO) extracts of Unani (Greek) medicines were investigated, employing sensitive techniques such as single cell gel electrophoresis (comet assay), cytokinesis-block micronucleus (CMBN), plasmid DNA nicking and Ames Salmonella mutagenicity assays. Unani medicines viz. Khamira Abraisham HK. Arshadwala (CCRUM-1), Itrifal-e-Ustukhaddus (CCRUM-2), Jawarish-e-jalinoos (CCRUM-3), Majoon-e-Suparipak ( ...

The well-crystallized ZnO nanoparticles were synthesized by a simple and facile soft chemical approach, and their induction of oxidative stress in Cloudman S91 melanoma cancer cells was studied. The ZnO nanoparticles were characterized for their morphology, structure, and optical properties. The ZnO nanoparticles with the average size of approximately 10 nm grew in high density, possessing wurtzite hexagonal phase. To study the induction of oxidative stress by ZnO nanoparticles in Cloudman S91 melanoma cancer cells, various doses of ZnO nanoparticles were treated with melanoma cancer cells for 24 h of incubation at 37 degrees C. The viability of the cells was analyzed with MTT method, whereas the morphology of the cells was observed via confocal laser scanning microscopy (CLSM), which revealed that when the time interval was increased, the number of cells decreased. The apoptosis-correlated, intracellular production of reactive oxygen species (ROS) was also measured with melanoma cancer cells with varying ZnO nanoparticle doses.

This paper reports the synthesis and characterization of ZnO nanoparticles prepared by soft chemical process. The nanoparticles of ZnO possess wurtzite hexagonal phase and were used for the induction of cell death in malignant human T98G gliomas, KB epithermoids and HEK normal non-malignant kidney cells. By applying ZnO nanoparticles, the cells exhibit that the nanoparticles are more efficacious on T98G cancer cells, moderately effective on KB cells and least toxic on normal human HEK cells. The results demonstrated that the treatment with ZnO nanoparticles sensitize T98G cells by increasing both the mitotic (linked to cytogenetic damage) and interphase (apoptosis) death. The ZnO nanoparticles behave as genotoxic drugs, since they induce a micronucleus formation in cells. The present study could be helpful in designing more potent anticancer agents for the therapeutic uses.

The formation of bacterial biofilm is a major challenge in clinical applications. The main aim of this study is to describe the synthesis, characterization and biocidal potential of zinc oxide nanoparticles (NPs) against bacterial strain Pseudomonas aeruginosa. These nanoparticles were synthesized via soft chemical solution process in a very short time and their structural properties have been investigated in detail by using X-ray diffraction and transmission electron microscopy measurements. In this work, the potential of synthesized ZnO-NPs (∼ 10-15 nm) has been assessed in-vitro inhibition of bacteria and the formation of their biofilms was observed using the tissue culture plate assays. The crystal violet staining on biofilm formation and its optical density revealed the effect on biofilm inhibition. The NPs at a concentration of 100 µg/mL significantly inhibited the growth of bacteria and biofilm formation. The biofilm inhibition by ZnO-NPs was also confirmed via bio-transmission electron microscopy (Bio-TEM). The Bio-TEM analysis of ZnO-NPs treated bacteria confirmed the deformation and damage of cells. The bacterial growth in presence of NPs concluded the bactericidal ability of NPs in a concentration dependent manner. It has been speculated that the antibacterial activity of NPs as a surface coating material, could be a feasible approach for controlling the pathogens. Additionally, the obtained bacterial solution data is also in agreement with the results from statistical analytical methods.

The critical need for development of reliable and eco-friendly processes for synthesis of metallic nanoparticles has recently been realized in the field of nanotechnology. Increasing awareness toward green chemistry and biological ­processes has elicited a desire to explore environmentally friendly approaches for the synthesis of nanoparticles as a safer alternative to physical and chemical methods, which involves harsh conditions and use of hazardous chemicals. Therefore, the use of natural resources, including bacteria and fungi, has been exploited for cost-­effective and environmentally nonhazardous nanoparticle synthesis. The rich microbial diversity of bacteria and fungi contains the innate potential for the synthesis of nanoparticles and may be regarded as potential biofactories. In fact, microbial ­synthesis of nanoparticles has emerged as an important branch of nanobiotechnology. The synthesis of inorganic materials by biological systems occurs through remarkable processes at ambient temperature and pressures and neutral pH. Among the various biological systems, bacteria are relatively easy to manipulate genetically, whereas fungi have an advantage of easy handling during downstream processing and large-scale production. In spite of the successes achieved in biological synthesis of nanoparticles, there is still a need to improve the rate of synthesis and monodispersity of nanoparticles. Also, microbial cultivation and downstream processing techniques must be improved, and more efficient methods should be developed. Furthermore, in order to exploit the system to its maximum potential, it is essential to understand the biochemical and molecular mechanisms involved in nanoparticle synthesis. Delineation of specific genomic pathways and characterization of gene products involved in biosynthesis of nanoparticles are required. The underlying molecular mechanisms that mediate microbial synthesis of nanoparticles will help in understanding the molecular switches and factors necessary to control the size and shape, as well as crystallinity of nanoparticles. Indeed, biological systems are still relatively unexplored, and therefore, the opportunities are open for budding nanobiotechnologists to utilize nonpathogenic biological systems for metallic nanoparticle synthesis with commercial perspectives.

Fluorescence quenching data on interaction of a fungicide methyl thiophanate (MT) with human serum albumin (HSA) elucidated a primary binding site at sub-domain IIA. Stern–Volmer algorithm and double log plot revealed the binding affinity (Ka) and capacity (n) of HSA as 1.65 × 104 M−1 and 1.0 (r2 = 0.99), respectively. Cyclic voltammetric and circular dichroism (CD) studies reaffirmed MT–HSA binding and demonstrated reduction in α-helical content of HSA. Substantial release of the carbonyl and acid-soluble amino groups from MT treated HSA suggested protein damage. The plausible mechanism of methyl (+CH3) group transfer from MT to side chain NH group of tryptophan and HSA degradation elucidates the toxicological and clinical implications of this fungicide.

A fungal strain, KSU-09, isolated from the roots of date palm (Phoenix dactylifera), was identified as Amylomyces rouxii based on sequence analysis of the internal transcribed spacer (ITS) region of its rRNA genes. Mycelia-free water extracts obtained from mycelium suspended in water for 72 h facilitated the production of stable, predominantly monodispersed and spherical silver nanoparticles (AgNPs) in the size range of 5–27 nm upon addition of 1 mM silver nitrate, as determined by the XRD, AFM and TEM. The AgNPs exhibited antimicrobial activity against Shigella dysenteriae type I, Staphylococcus aureus, Citrobacter sp., Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Candida albicans and Fusarium oxysporum. Thus, the strain KSU-09 could be used for simple, non-hazardous and efficient synthesis of antimicrobial AgNPs.

The critical need for development of reliable and eco-friendly processes for synthesis of metallic nanoparticles has recently been realized in the field of nanotechnology. Increasing awareness toward green chemistry and biological processes has elicited a desire to explore environmentally friendly approaches for the synthesis of nanoparticles as a safer alternative to physical and chemical methods, which involves harsh conditions and use of hazardous chemicals. Therefore, the use of natural resources, including bacteria and fungi, has been ...

Biodegradation of phenylurea herbicide isoproturon was studied in soil microcosm bioaugmented with a novel bacterial strain JS-11 isolated from wheat rhizosphere. The molecular characterization based on 16SrDNA sequence homology confirmed its identity as Pseudomonas aeruginosa strain JS-11. The herbicide was completely degraded within 20 days at ambient temperature with the rate constant of 0.08 day(-1), following the first-order rate kinetics. In stationary phase, at a cell density of 6.5 × 10(9) CFU mL(-1), the bacteria produced substantially increased amounts of indole acetic acid (IAA) in the presence of tryptophan as compared with the control. Also, the bacteria exhibited a time-dependent increase in the amount of tri-calcium phosphate solubilization in Pikovskaya's medium. Further screening of the strain JS-11 for auxiliary activities revealed its remarkable capability of producing the siderophores and hydrogen cyanide (HCN), besides antifungal activity against a common phytopathogen Fusarium oxysporum. Thus, the versatile P. aeruginosa strain JS-11 with innate potential for multifarious biological activities is envisaged as a super-bioinoculant for exploitation in the integrated bioremediation, plant growth and disease management (IBPDM) in contaminated agricultural soils.