Utpal Pandya

University of Houston | U of H, UH

Streptococcus pneumoniae, a facultative human pathogen associated with wide variety of diseases, such as pneumonia, meningitis, sepsis and otitis media. Factors involved in the initial colonization, survival and etiology of this commensal bacteria in the human host from the ex vivo environment is still not clearly understood. Here, we report altera...

High-aspect rotating vessels (HARVs) are used to study the effects low-shear modeled microgravity (LSMMG) on bacterial gene expression. LSMMG is generated by orienting HARVs with the axis of rotation perpendicular to the gravity vector while gravitational controls are oriented with the axis of rotation parallel to the gravity vector. Microarray ana...

Space flight has been shown to result in altered immune responses. The current study was designed to investigate this possibility by using the bed rest model of some space flight conditions. A large number of women are included as subjects in the study. The hypothesis being tested is: 60 days head-down tilt bed rest of humans will affect the immune...

Streptococcus pneumoniae is a common commensal of the upper respiratory tract of healthy humans and is an important pathogen in young children, immunocompromised adults, and the elderly. To better understand the strategies employed by this bacterial species in adapting to conditions present at different infection sites in the host, global transcrip...

A protein chip-based proteomics profiling platform employing SELDI-TOF mass spectrometry was used to identify differentially expressed proteins of Streptococcus pneumoniae. The bacterial pellets from the 100 ml culture were washed and resuspended in 5ml PBS supplemented with 1mM PMSF prior to sonication. The clarified cell lysates were normalized a...

The physiological significance of the selenium-independent glutathione peroxidase (GPx) activity of glutathione S-transferases (GSTs), associated with the major Alpha class isoenzymes hGSTA1-1 and hGSTA2-2, is not known. In the present studies we demonstrate that these isoenzymes show high GPx activity toward phospholipid hydroperoxides (PL-OOH) an...

We have recently shown that RLIP76, a Ral-binding, GTPase-activating protein, is an ATP-dependent transporter of doxorubicin (DOX) as well as glutathione conjugates [Awasthi, S., et al. (2000) Biochemistry 39, 9327−9334]. RLIP76 overexpressed in human cells or transformed E. coli undergoes proteolysis to yield several fragments, including two promi...

Using antibodies against S-(2,4-dinitrophenyl)glutathione (DNP-SG) ATPase, we have cloned RLIP76, a Ral-binding, GTPase-activating protein involved in Ras-Ral-Rho signaling pathway. Recombinant RLIP76 shows DOX and DNP-SG-stimulated ATPase activity comparable to that of DNP-SG ATPase. When reconstituted in proteoliposomes, RLIP76 mediates ATP-depen...

Human glutathione S-transferases (GSTs) hGSTA1-1 and hGSTA2-2 catalyze glutathione-dependent reduction of phospholipid hydroperoxides (P-OOH) and 5-hydroperoxyeicosatetraenoic acid (5-HPETE). In human liver these isozymes contribute to a major portion of glutathione peroxidase activity towards P-OOH. K562 cells transfected with hGSTA1-1, hGSTA2-2,...

Clinical efficacy of alkylating anticancer drugs, such as chlorambucil, is often limited by the emergence of drug resistant tumor cells. Increased glutathione (GSH) conjugation (inactivation) of alkylating anticancer drugs or their activated metabolites due to overexpression of the Pi class GSH S-transferase (hGSTP1-1) is believed to be an importan...

Curcumin (diferuloylmethane), a yellow pigment of turmeric with antioxidant properties has been shown to be a cancer preventative in animal studies. It contains two electrophilic alpha, beta-unsaturated carbonyl groups, which can react with nucleophilic compounds such as glutathione (GSH), but formation of the GSH-curcumin conjugates has not previo...

Active transport of conjugated and unconjugated electrophiles out of cells is essential for cellular homeostasis. We have previously identified in human tissues a transporter, DNP-SG [S-(2,4-dinitrophenyl)glutathione] ATPase, capable of carrying out this function [Awasthi et al. (1998) Biochemistry 37, 5231−5238, 5239−5248]. We now report the cloni...

Administration of naphthalene is known to cause cataract formation in rats and rabbits and naphthalene-initiated cataract is frequently used as a model for studies on senile cataract in humans. Oxidative stress has been implicated in the mechanism of naphthalene-induced cataract. Curcumin, a constituent of turmeric, a spice used in Indian curry dis...

Our previous studies have shown that curcumin, a dietary antioxidant present in turmeric, attenuates 4-hydroxynonenal induced lens opacification in organ culture (Awasthi et al, Amer. J. Clin. Nutr. 1996;64:761–766). Oxidative stress has been implicated in the mechanism of galactosemic cataract formation. Therefore, the present studies were designe...

To delineate the role of the glutathione S-transferase (GST) isozyme hGST 5.8 in protection mechanisms against oxidative stress, the effect of low-level transient exposure of H2O2 to retinal pigmented epithelial (RPE) cells on hGST 5.8 and other enzymes involved in defense against oxidative stress was examined. Cultured human RPE cells were exposed...

Curcumin, an antioxidant present in the spice turmeric (Curcuma longa), has been shown to inhibit chemical carcinogenesis in animal models and has been shown to be an anti-inflammatory agent. While mechanisms of its biological activities are not understood, previous studies have shown that it modulates glutathione (GSH)-linked detoxification mechan...

In order to elucidate the protective role of glutathione S-transferases (GSTs) against oxidative stress, we have investigated the kinetic properties of the human α-class GSTs, hGSTA1-1 and hGSTA2-2, toward physiologically relevant hydroperoxides and have studied the role of these enzymes in glutathione (GSH)-dependent reduction of these hydroperoxi...

We have recently demonstrated mutually inhibitory ATP-dependent transport of dinitrophenyl-S-glutathione (DNP-SG) and doxorubicin by DNP-SG ATPase purified from human erythrocyte membranes (S. Awasthiet al.,1998a,b). Our previous studies indicate a broad substrate specificity for this transport mechanism, including someP-glycoprotein substrates. Pr...

We have studied the filarial parasites Brugia malayi, Acanthocheilonema viteae and Setaria cervi adults and microfilariae of malayi and S. cervi and demonstrated the presence of ATP-independent (Topo I) and ATP-dependent (TOPO II) DNA topoisomerase activities. The enzyme activities were localized in the nuclear fraction of the parasites. Their dist...

The interaction of DNA from filarial parasite Setaria cervi with polyamines was monitored by melting temperature (Tm) profile, condensation and B to Z DNA transition and compared with DNA of Escherichia coli, Micrococcus luteus and calf thymus having different GC content. Polyamines, viz. spermine and spermidine, stabilized the secondary structure...

The bovine filarial parasite Setaria cervi adult females and its microfilarial stage possessed an active antioxidant system. Appreciable activities of superoxide dismutase, catalase, xanthine oxidase and glutathione peroxidase were detected in both the stages of parasite. The glutathione reductase, glucose-6­ phosphate dehydrogenase, glutathione-s-...

Long-term habitation in space exposes humans to a variety of environmental stresses not encountered on earth such as ionizing radiation and microgravity. Decreases in immune function and increases in microbial growth and antibiotic resistance during space flight could create an increased health risk to crewmembers (Sonnenfeld et al., 1990; Mishra e...

Estimates of 7x105 cubic meters of crude oil were released into the Gulf of Mexico as a consequence of the April 20th, 2010 Deep Water Horizon drilling rig explosion, leaving thousands of square miles of earth's surface covered in crude oil. Dispersants were used on large slicks and injected at the well head, resulting in oil being suspended throug...