Javed Musarrat

Oxidative stress mediated apoptosis induced by nickel ferrite nanoparticles in cultured A549 cells

Due to the interesting magnetic and electrical properties with good chemical and thermal stabilities, nickel ferrite nanoparticles are being utilized in many applications including magnetic resonance imaging, drug delivery and hyperthermia. Recent studies have shown that nickel ferrite nanoparticles produce cytotoxicity in mammalian cells. However, there is very limited information concerning the toxicity of nickel ferrite nanoparticles at the cellular and molecular level. The aim of this study was to investigate the cytotoxicity, oxidative stress and apoptosis induction by well-characterized nickel ferrite nanoparticles (size 26 nm) in human lung epithelial (A549) cells. Nickel ferrite nanoparticles induced dose-dependent cytotoxicity in A549 cells demonstrated by MTT, NRU and LDH assays. Nickel ferrite nanoparticles were also found to induce oxidative stress evidenced by generation of reactive oxygen species (ROS) and depletion of antioxidant glutathione (GSH). Further, co-treatment with the antioxidant L-ascorbic acid mitigated the ROS generation and GSH depletion due to nickel ferrite nanoparticles suggesting the potential mechanism of oxidative stress. Quantitative real-time PCR analysis demonstrated that following the exposure of A549 cells to nickel ferrite nanoparticles, the level of mRNA expressions of cell cycle checkpoint protein p53 and apoptotic proteins (bax, caspase-3 and caspase-9) were significantly up-regulated, whereas the expression of anti-apoptotic proteins (survivin and bcl-2) were down-regulated. Moreover, activities of caspase-3 and caspase-9 enzymes were also significantly higher in nickel ferrite nanoparticles exposed cells. To the best of our knowledge this is the first report showing that nickel ferrite nanoparticles induced apoptosis in A549 cells through ROS generation and oxidative stress via p53, survivin, bax/bcl-2 and caspase pathways.

Characterization of a new Pseudomonas aeruginosa strain NJ-15 as a potential biocontrol agent.

Phylogenetic characterization of soil isolate NJ-15, based on sequence homology of a partial 746-bp fragment of 16SrDNA amplicon, with the ribosomal database sequences (http://www.msu.edu/RDP/cgis/phylip.cgi), validated the strain as Pseudomonas aeruginosa. The strain NJ-15 produced a substantial amount of indole acetic acid (IAA) in tryptophan-supplemented medium. Besides, the strain also exhibited significant production of both the siderophore and hydrogen cyanide (HCN) on chrome azurol S and Kings B media, respectively. The data revealed lower HCN production under iron-limiting conditions vis-à-vis higher HCN release with iron stimulation. Significant growth inhibition of phytopathogenic fungi occurred in the order as Fusarium oxysporum > Trichoderma herizum > Alternaria alternata > Macrophomina phasiolina upon incubation with strain NJ-15 cells. Thus, the secondary metabolites producing new Pseudomonas aeruginosa strain NJ-15 exhibited innate potential of plant growth promotion and biocontrol activities in vitro.

Titanium dioxide nanoparticles induced cytotoxicity, oxidative stress and DNA damage in human amnion epithelial (WISH) cells

Titanium dioxide nanoparticles (TiO(2)-NPs) induced cytotoxicity and DNA damage have been investigated using human amnion epithelial (WISH) cells, as an in vitro model for nanotoxicity assessment. Crystalline, polyhedral rutile TiO(2)-NPs were synthesized and characterized using X-ray diffraction (XRD), UV-Visible spectroscopy, Fourier transform infra red (FTIR) spectroscopy, and transmission electron microscopic (TEM) analyses. The neutral red uptake (NRU) and [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) assays revealed the concentration dependent cytotoxic effects of TiO(2)-NPs (30.6nm) in concentration range of 0.625-10μg/ml. Cells exposed to TiO(2)-NPs (10μg/ml) exhibited significant reduction (46.3% and 34.6%; p<0.05) in catalase activity and glutathione (GSH) level, respectively. Treated cells showed 1.87-fold increase in intracellular reactive oxygen species (ROS) generation and 7.3% (p<0.01) increase in G(2)/M cell cycle arrest, as compared to the untreated control. TiO(2)-NPs treated cells also demonstrated the formation of DNA double strand breaks with 14.6-fold (p<0.05) increase in Olive tail moment (OTM) value at 20μg/ml concentration, vis-à-vis untreated control, under neutral comet assay conditions. Thus, the reduction in cell viability, morphological alterations, compromised antioxidant system, intracellular ROS production, and significant DNA damage in TiO(2)-NPs exposed cells signify the potential of these NPs to induce cyto- and genotoxicity in cultured WISH cells.

Chitinases: An update

Chitin, the second most abundant polysaccharide in nature after cellulose, is found in the exoskeleton of insects, fungi, yeast, and algae, and in the internal structures of other vertebrates. Chitinases are enzymes that degrade chitin. Chitinases contribute to the generation of carbon and nitrogen in the ecosystem. Chitin and chitinolytic enzymes are gaining importance for their biotechnological applications, especially the chitinases exploited in agriculture fields to control pathogens. Chitinases have a use in human health care, especially in human diseases like asthma. Chitinases have wide-ranging applications including the preparation of pharmaceutically important chitooligosaccharides and N-acetyl D glucosamine, preparation of single-cell protein, isolation of protoplasts from fungi and yeast, control of pathogenic fungi, treatment of chitinous waste, mosquito control and morphogenesis, etc. In this review, the various types of chitinases and the chitinases found in different organisms such as bacteria, plants, fungi, and mammals are discussed.

Apoptosis induction by silica nanoparticles mediated through reactive oxygen species in human liver cell line HepG2.

Silica nanoparticles are increasingly utilized in various applications including agriculture and medicine. In vivo studies have shown that liver is one of the primary target organ of silica nanoparticles. However, possible mechanisms of hepatotoxicity caused by silica nanoparticles still remain unclear. In this study, we explored the reactive oxygen species (ROS) mediated apoptosis induced by well-characterized 14nm silica nanoparticles in human liver cell line HepG2. Silica nanoparticles (25-200μg/ml) induced a dose-dependent cytotoxicity in HepG2 cells. Silica nanoparticles were also found to induce oxidative stress in dose-dependent manner indicated by induction of ROS and lipid peroxidation and depletion of glutathione (GSH). Quantitative real-time PCR and immunoblotting results showed that both the mRNA and protein expressions of cell cycle checkpoint gene p53 and apoptotic genes (bax and caspase-3) were up-regulated while the anti-apoptotic gene bcl-2 was down-regulated in silica nanoparticles treated cells. Moreover, co-treatment of ROS scavenger vitamin C significantly attenuated the modulation of apoptotic markers along with the preservation of cell viability caused by silica nanoparticles. Our data demonstrated that silica nanoparticles induced apoptosis in human liver cells, which is ROS mediated and regulated through p53, bax/bcl-2 and caspase pathways. This study suggests that toxicity mechanisms of silica nanoparticles should be further investigated at in vivo level.

Production of antimicrobial silver nanoparticles in water extracts of the fungus Amylomyces rouxii strain KSU-09.

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 72h facilitated the production of stable, predominantly monodispersed and spherical silver nanoparticles (AgNPs) in the size range of 5-27nm upon addition of 1mM 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.

Microbial strategies for crop improvement

The Use of Microorganisms to Facilitate the Growth of Plants in Saline Soils.- Recent Advances in Plant Growth Promotion by Phosphate-Solubilizing Microbes.- Developing Beneficial Microbial Biofilms on Roots of Non legumes: A Novel Biofertilizing Technique.- Role of 1-Aminocyclopropane-1-carboxylate deaminase in Rhizobium-Legume Symbiosis.- Strategies for Crop Improvement in Contaminated Soils Using Metal-Tolerant Bioinoculants.- Functional Diversity Among Plant Growth-Promoting Rhizobacteria: Current Status.- Plant Growth Promoting Rhizobacteria and Sustainable Agriculture.- Soil Health - A Precondition for Crop Production.- Recent Advances in Biopesticides.- Benefits of Arbuscular Mycorrhizal Fungi to Sustainable Crop Production.- Enhancement of Rhizobia-Legumes Symbioses and Nitrogen Fixation for Crops Productivity Improvement.- Monitoring the Development of Nurse Plant Species to Improve the Performances of Reforestation Programs in Mediterranean Areas.- Pea Cultivation in Saline Soils: Influence of Nitrogen Nutrition.- Plant Growth-Promoting Diazotrophs and Productivity of Wheat on the Canadian Prairies.- Factors Affecting the Variation of Microbial Communities in Different Agro-Ecosystems.- Strategies for Utilizing Arbuscular Mycorrhizal Fungi and Phosphate-Solubilizing Microorganisms for Enhanced Phosphate Uptake and Growth of Plants in the Soils of the Tropics.

Differential binding of tetracyclines with serum albumin and induced structural alterations in drug-bound protein

Interaction of tetracycline (TC) derivatives viz. oxytetracycline, doxycycline, demeclocycline and chlorotetracycline with bovine serum albumin (BSA) and concomitant changes in protein conformation were studied using fluorescence quenching and circular dichroism measurements. Fluorescence data revealed the presence of one to three binding sites on BSA for different TC derivatives. Binding studies with the marker ligands, warfarin and bilirubin, elucidated site-I as a primary binding site for TCs on albumin. Scatchard analysis revealed the binding affinity (K(a)) and capacity (n) for these derivatives vary in the range from 0.8 to 3.2 x 10(6) l/mole and 1.3-3.4, respectively. Significant reduction (60-45%) in secondary structure (alpha-helical content) of BSA was noticed upon interaction with different TC derivatives in presence of Cu (II) ions. High affinity binding of TCs with BSA signifies drug stability. However, excessive binding at higher TC concentrations in combination with Cu (II) induces conformational change in protein structure, which may exert detrimental effect on cellular protein.

Copper oxide nanoparticles induced mitochondria mediated apoptosis in human hepatocarcinoma cells.

Copper oxide nanoparticles (CuO NPs) are heavily utilized in semiconductor devices, gas sensor, batteries, solar energy converter, microelectronics and heat transfer fluids. It has been reported that liver is one of the target organs for nanoparticles after they gain entry into the body through any of the possible routes. Recent studies have shown cytotoxic response of CuO NPs in liver cells. However, the underlying mechanism of apoptosis in liver cells due to CuO NPs exposure is largely lacking. We explored the possible mechanisms of apoptosis induced by CuO NPs in human hepatocellular carcinoma HepG2 cells. Prepared CuO NPs were spherical in shape with a smooth surface and had an average diameter of 22 nm. CuO NPs (concentration range 2–50 µg/ml) were found to induce cytotoxicity in HepG2 cells in dose-dependent manner, which was likely to be mediated through reactive oxygen species generation and oxidative stress. Tumor suppressor gene p53 and apoptotic gene caspase-3 were up-regulated due to CuO NPs exposure. Decrease in mitochondrial membrane potential with a concomitant increase in the gene expression of bax/bcl2 ratio suggested that mitochondria mediated pathway involved in CuO NPs induced apoptosis. This study has provided valuable insights into the possible mechanism of apoptosis caused by CuO NPs at in vitro level. Underlying mechanism(s) of apoptosis due to CuO NPs exposure should be further invested at in vivo level.

ZnO nanoparticles induced oxidative stress and apoptosis in HepG2 and MCF-7 cancer cells and their antibacterial activity.

Liver and breast cancer are the most traumatic diseases because they affect the major organs of the body. Nanomedicine recently emerged as a better option for the treatment of these deadly diseases. As a result, many nanoparticles have been used to treat cancer cell lines. Of the various nanoparticles, zinc oxide exhibits biocompatibility. Therefore, the aim of the present study was to investigate the activity of zinc oxide nanoparticles (ZnO-NPs) against HepG2 and MCF-7 cells. The NPs (∼13±2 nm) were prepared via a non-protonated chemical route and were well-characterized through standard techniques. The study showed that treatment with NPs is notably effective against the proliferation of HepG2 and MCF-7 cancer cells in a dose-dependent manner. The MTT (3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide, a tetrazole) assays revealed the concentration-dependent cytotoxic effects of NPs in range of 2.5-100 μg/ml. HepG2 and MCF-7 cells were exposed to ZnO-NPs and exhibited a significant reduction in their cell viability (95% and 96%; p<0.05) in response to a very low concentration (25 μg/ml) of the ZnO-NPs; this finding was confirmed with FACS (fluorescence-activated cell sorting) data. The reduction in cell viability in response to NP treatment induces cytotoxicity in the cultured cells. The quantitative RT-PCR (real-time polymerase chain reaction) results demonstrate that the exposure of HepG2 cells to ZnO-NPs results in significant upregulation of the mRNA expression level of Bax, p53, and caspase-3 and the down regulation of the anti-apoptotic gene Bcl-2. The NPs were also tested against five pathogenic bacteria through the disk diffusion method, and their antibacterial activities were compared with that of ZnO salt.