Publications (31)88.33 Total impact
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Article: Pan-neuronal expression of APL-1, an APP-related protein, disrupts olfactory, gustatory, and touch plasticity in Caenorhabditis elegans.
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ABSTRACT: Patients with Alzheimer's disease show age-related cognitive decline. Postmortem autopsy of their brains shows the presence of large numbers of senile plaques, whose major component is the β-amyloid peptide. The β-amyloid peptide is a cleavage product of the amyloid precursor protein (APP). In addition to the neurodegeneration associated with β-amyloid aggregation in Alzheimer's disease patients, mutations in APP in mammalian model organisms have also been shown to disrupt several behaviors independent of visible amyloid plaque formation. However, the pathways in which APP function are unknown and difficult to unravel in mammals. Here we show that pan-neuronal expression of APL-1, the Caenorhabditis elegans ortholog of APP, disrupts several behaviors, such as olfactory and gustatory learning behavior and touch habituation. These behaviors are mediated by distinct neural circuits, suggesting a broad impact of APL-1 on sensory plasticity in C. elegans. Furthermore, we found that disruption of these three behaviors requires activity of the TGFβ pathway and reduced activity of the insulin pathway. These results suggest pathways and molecular components that may underlie behavioral plasticity in mammals and in patients with Alzheimer's disease.Journal of Neuroscience 07/2012; 32(30):10156-69. · 7.11 Impact Factor -
Article: Cyanobacterial hydrogen production
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ABSTRACT: With the global attention and research now being focussed on looking for an alternative to fossil fuel, hydrogen is the hope of future. Cyanobacteria are highly promising microorganisms for biological photohydrogen production. The review highlights the advancement in the biology of cyanobacterial hydrogen production in recent years. It discusses the enzymes involved in hydrogen production, viz. hydrogenases and nitrogenases, various strategies developed by cyanobacteria to limit nitrogenase inactivation by atmospheric and photosynthetic O2, different biochemical and physicochemical parameters influencing the commercial cyanobacterial hydrogen production and the methods opted by different researchers for eliminating them to obtain maximum and sustained hydrogen production. Integrating the existing knowledge, techniques and expertise available, much future improvement and progress can be made in the field.World Journal of Microbiology and Biotechnology 04/2012; 16(8):757-767. · 1.53 Impact Factor -
Article: Antibacterial activity of polymer coated cerium oxide nanoparticles.
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ABSTRACT: Cerium oxide nanoparticles have found numerous applications in the biomedical industry due to their strong antioxidant properties. In the current study, we report the influence of nine different physical and chemical parameters: pH, aeration and, concentrations of MgSO(4), CaCl(2), KCl, natural organic matter, fructose, nanoparticles and Escherichia coli, on the antibacterial activity of dextran coated cerium oxide nanoparticles. A least-squares quadratic regression model was developed to understand the collective influence of the tested parameters on the anti-bacterial activity and subsequently a computer-based, interactive visualization tool was developed. The visualization allows us to elucidate the effect of each of the parameters in combination with other parameters, on the antibacterial activity of nanoparticles. The results indicate that the toxicity of CeO(2) NPs depend on the physical and chemical environment; and in a majority of the possible combinations of the nine parameters, non-lethal to the bacteria. In fact, the cerium oxide nanoparticles can decrease the anti-bacterial activity exerted by magnesium and potassium salts.PLoS ONE 01/2012; 7(10):e47827. · 4.09 Impact Factor -
Article: Bacterial and archaea community present in the Pine Barrens Forest of Long Island, NY: unusually high percentage of ammonia oxidizing bacteria.
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ABSTRACT: Of the few preserved areas in the northeast of United States, the soil in the Pine Barrens Forests presents a harsh environment for the microorganisms to grow and survive. In the current study we report the use of clustering methods to scientifically select the sampling locations that would represent the entire forest and also report the microbial diversity present in various horizons of the soil. Sixty six sampling locations were selected across the forest and soils were collected from three horizons (sampling depths). The three horizons were 0-10 cm (Horizon O); 11-25 cm (Horizon A) and 26-40 cm (Horizon B). Based on the total microbial substrate utilization pattern and K-means clustering analysis, the soil in the Pine Barrens Forest can be classified into four distinct clusters at each of the three horizons. One soil sample from each of the four clusters were selected and archaeal and bacterial populations within the soil studied using pyrosequencing method. The results show the microbial communities present in each of these clusters are different. Within the microbial communities present, microorganisms involved in nitrogen cycle occupy a major fraction of microbial community in the soil. High level of diversity was observed for nitrogen fixing bacteria. In contrast, Nitrosovibrio and Nitrosocaldus spp are the single bacterial and archaeal population respectively carrying out ammonia oxidation in the soil.PLoS ONE 01/2011; 6(10):e26263. · 4.09 Impact Factor -
Article: Understanding the toxicity of aggregated zero valent copper nanoparticles against Escherichia coli.
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ABSTRACT: Copper nanoparticles are used in wide variety of applications and in the current study we report the antimicrobial activity of these particles. Influence of pH, temperature, aeration rate, concentration of nanoparticles and concentration of bacteria on the toxicity of copper nanoparticles against Escherichia coli have been studied using a centroid mixture design of experiment. The linear and quadratic regression model shows that the toxicity of copper nanoparticles not only depends on the primary effect of the parameters tested (pH, temperature, aeration, concentration of E. coli and concentration of nanoparticles), but also on the interactive effect of these parameters.Journal of hazardous materials 08/2010; 180(1-3):212-6. · 4.14 Impact Factor -
Article: Optimization of the fermentation media for sophorolipid production from Candida bombicola ATCC 22214 using a simplex centroid design.
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ABSTRACT: This article describes the use of a simplex centroid mixture experimental design to optimize the fermentation medium in the production of sophorolipids (SLs) using Candida bombicola. In the first stage, 16 media ingredients were screened for the ones that have the most positive influence on the SL production. The sixteen ingredients that were chosen are five different carbohydrates (fructose, glucose, glycerol, lactose, and sucrose), five different nitrogen sources (malt extract, peptone extract, soytone, urea, and yeast extract), two lipid sources (mineral oil and oleic acid), two phosphorus sources (K(2)HPO(4) and KH(2)PO(4)), MgSO(4), and CaCl(2). Multiple regression analysis and centroid effect analysis were carried out to find the sugar, lipid, nitrogen source, phosphorus source, and metals having the most positive influence. Sucrose, malt extract, oleic acid, K(2)HPO(4), and CaCl(2) were selected for the second stage of experiments. An augmented simplex centroid design for five ingredients requiring 16 experiments was used for the optimization stage. This produced a quadratic model developed to help understand the interaction amongst the ingredients and find the optimal media concentrations. In addition, the top three results from the optimization experiments were used to obtain constraints that identify an optimal region. The model together with the optimal region constraints predicts the maximum production of SLs when the fermentation media is composed of sucrose, 125 g/L; malt extract, 25 g/L; oleic acid, 166.67 g/L; K(2)HPO(4), 1.5 g/L; and CaCl(2), 2.5 g/L. The optimal media was validated experimentally and a yield of 177 g/L was obtained.Biotechnology Progress 02/2010; 26(4):938-44. · 2.34 Impact Factor -
Article: Influence of iron and copper nanoparticle powder on the production of lignocellulose degrading enzymes in the fungus Trametes versicolor.
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ABSTRACT: White rot fungi are one of the key group of microorganisms that help to enrich the soil via degradation of wood. In the current communication, influence of iron and copper nanoparticles on the production of lignocellulolytic enzymes by Trametes versicolor have been investigated. The production of enzymes in the presence of the two nanoparticles was compared to that of ferrous and cupric ions respectively. Results show that both the tested nanoparticles alter the production profile of the lignocellulolytic enzymes when compared to the control set. The production of laccase was not influenced by iron nanoparticles but was effected by copper nanoparticles within 24h of incubation. Both the nanoparticles decreased the production of beta-glucosidase, beta-xylosidase and cellobiohydrolase significantly. However, the production profile of Mn-peroxidase and remained statistically similar to that of control when the organism was incubated with iron and copper nanoparticles. The production profiles were also different when one compares the ionic form of metals and the nanoparticles, suggesting different mechanism of action of the particles on the organism. The difference in the production profile was not growth related as no significant difference was recorded for either form of iron and copper on the growth of T. versicolor.Journal of hazardous materials 02/2010; 178(1-3):1141-5. · 4.14 Impact Factor -
Article: A new efficient mixture screening design for optimization of media.
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ABSTRACT: Screening ingredients for the optimization of media is an important first step to reduce the many potential ingredients down to the vital few components. In this study, we propose a new method of screening for mixture experiments called the centroid screening design. Comparison of the proposed design with Plackett-Burman, fractional factorial, simplex lattice design, and modified mixture design shows that the centroid screening design is the most efficient of all the designs in terms of the small number of experimental runs needed and for detecting high-order interaction among ingredients.Biotechnology Progress 07/2009; 25(4):980-5. · 2.34 Impact Factor -
Article: Identification and quantification of sophorolipid analogs using ultra-fast liquid chromatography-mass spectrometry.
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ABSTRACT: An ultra-fast liquid chromatographic method combined with atmospheric pressure chemical ionization mass detection (UHPLC/APCI-MS) has been developed for the separation and quantification of sophorolipid analogs produced by the yeast Candida bombicola. The sophorolipid mixture was produced by growing the yeast in the presence of glucose and oleic acid under higher aeration. It was found that more than 95% of the analogs are lactonic sophorolipids and all the produced sophorolipids produced were either mono- or di-acetylated. Also observed was a sophorolipid analog with a tri-unsaturated fatty acid, which has not been reported previously.Journal of microbiological methods 07/2009; 78(3):354-6. · 2.43 Impact Factor -
Article: Sophorolipids improve sepsis survival: effects of dosing and derivatives.
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ABSTRACT: Sophorolipids, a family of natural and easily chemo-enzymatically modified microbial glycolipids, are promising modulators of the immune response. We have previously demonstrated that sophorolipids mediate anti-inflammatory effects, including decreasing sepsis-related mortality at 36 h in vivo in a rat model of septic peritonitis and in vitro by decreasing nitric oxide and inflammatory cytokine production. Here we assessed the effect of sophorolipids on sepsis-related mortality when administered as a (1) single bolus versus sequential dosing and (2) natural mixture versus individual derivatives compared with vehicle alone. Intra-abdominal sepsis was induced in male, Sprague Dawley rats, 200 to 240 g, via cecal ligation and puncture. Sophorolipids (5-750 mg/kg) or vehicle (ethanol/sucrose/physiological saline) were injected intravenously (i.v.) via tail vein or inferior vena cava at the end of the operation either as a single dose or sequentially (q24 h x 3 doses); natural mixture was compared with select sophorolipid derivatives (n = 10-15 per group). Sham-operated animals served as nonsepsis controls. Survival rates were compared at 1 through 6 d post sepsis induction and tissue was analyzed by histopathology. Significance was determined by Kruskal-Wallis analysis with Bonferroni adjustment and Student's t-test. Sophorolipid treatment at 5 mg/kg body weight improved survival in rats with cecal ligation and puncture-induced septic shock by 28% at 24 h and 42% at 72 h for single dose, 39% at 24 h and 26% at 72 h for sequential doses, and 23% overall survival for select sophorolipid derivatives when compared with vehicle control (P < 0.05 for sequential dosing). Toxicity was evident and dose-dependent with very high doses of sophorolipid (375-750 mg/kg body weight) with histopathology demonstrating interstitial and intra-alveolar edema with areas of microhemorrhage in pulmonary tissue when compared with vehicle controls (P < 0.05). No mortality was observed in sham operated controls at all doses tested. Administration of sophorolipids after induction of intra-abdominal sepsis improves survival. The demonstration that sophorolipids can reduce sepsis-related mortality with different dosing regimens and derivatives provides continuing evidence toward a promising new therapy. Toxicity is evident at 75 to 150x the therapeutic dose in septic animals.Journal of Surgical Research 10/2007; 142(2):314-9. · 2.25 Impact Factor -
Article: Development of a new approach for microbial decontamination of water using modified Fenton's reaction.
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ABSTRACT: Microbial decontamination of water was carried out using a novel radical generating system consisting of ion exchange resin, copper and hydrogen peroxide. The system was successful in reducing the microbial load in water by more than 99% in 15 min and is effective against all the microorganisms tested. The method was also successful in decontaminating the flood water obtained from Industrial Canal and 17th Street Canal in New Orleans. Decontamination is due to the formation of hydroxyl radicals, formed during the decomposition of hydrogen peroxide by the metal-polymer complex.Environmental Pollution 08/2007; 148(2):674-8. · 3.75 Impact Factor -
Article: Mixture design as a first step for optimization of fermentation medium for cutinase production from Colletotrichum lindemuthianum.
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ABSTRACT: Cutinase enzymes from fungi have found diverse applications in industry. However, most of the available literature on cutinase production is related to the cultivation of genetically engineered bacteria or yeast cells. In the present study, we use mixture design experiments to evaluate the influence of six nutrient elements on production of cutinase from the fungus Colletotrichum lindemuthianum. The nutritional elements were starch, glucose, ammonium sulfate, yeast extract, magnesium sulfate, and potassium phosphate. In the experimental design, we imposed the constraints that exactly one factor must be omitted in each set of experiments and no factor can account for more than one third of the mixture. Thirty different sets of experiments were designed. Results obtained showed that while starch is found to have negative influence on the production of the enzyme, yeast extract and potassium phosphate have a strong positive influence. Magnesium sulfate, ammonium sulfate, and glucose have low positive influence on the enzyme production. Contour plots have also been created to obtain information concerning the interaction effects of the media components on enzyme production.Journal of Industrial Microbiology and Biotechnology 06/2007; 34(5):349-55. · 2.73 Impact Factor -
Article: Sophorolipids having enhanced antibacterial activity.
Antimicrobial Agents and Chemotherapy 02/2007; 51(1):397-400. · 4.84 Impact Factor -
Article: Glycolipid Polymer Synthesized from Natural Lactonic Sophorolipids by Ring-Opening Metathesis Polymerization
Macromolecules 01/2007; 40(2):145-147. · 5.17 Impact Factor -
Article: Cyanobacterial flora from polluted marine shores.
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ABSTRACT: Citation of cyanobacterial cultures from the shores of south west coast of Gujarat, India and their relationship with sea water quality, influenced by extensive pollutant runoff is reported in this study. Intensity of pollution was evaluated by physico-chemical analysis of water. Higher load of suspended solids (60-1000 mg l(-1)) and nutrients (PO4- P: 1.3-4 micromole l(-1) and NO3- N: 12.5-17.8 micromole l(-1)) were persistent throughout the analysis. Community structure is seen to be influenced by such persistent pollution. Twenty nine cyanobacterial species were isolated belonging to 9 genera of 4 families, with an elevated occurrence of Oscillatoria and Lyngbya species. No heterocystous cyanobacteria were isolated throughout the study.Environmental Monitoring and Assessment 10/2006; 120(1-3):407-14. · 1.40 Impact Factor -
Article: Cyanobacterial flora from polluted industrial effluents.
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ABSTRACT: Effluents originating from pesticides, agro-chemicals, textile dyes and dyestuffs industries are always associated with high turbidity, colour, nutrient load, and heavy metals, toxic and persistent compounds. But even with such an anthropogenic nature, these effluents contain dynamic cyanobacterial communities. Documentation of cyanobacterial cultures along the water channels of effluents discharged by above mentioned industries along the west coast of India and their relationship with water quality is reported in this study. Intensity of pollution was evaluated by physico-chemical analysis of water. Higher load of solids, carbon and nutrients were found to be persistent throughout the analysis. Sediment and water samples were found to be colored in nature. Cyanobacterial community structure was found to be influenced by the anthropogenic pollution. 40 different cyanobacterial species were recorded from 14 genera of 5 families and an elevated occurrence of Phormidium, Oscillatoria and Chroococcus genera was observed in all the sampling sites.Environmental Monitoring and Assessment 06/2006; 116(1-3):91-102. · 1.40 Impact Factor -
Article: Influence of dimethyl sulfoxide on extracellular enzyme production by Pleurotus ostreatus.
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ABSTRACT: Dimethyl sulfoxide (DMSO) is commonly used as a co-solvent to dissolve poorly water-soluble biologically active agents to assess their biological activities such as for enzyme induction. The question addressed was whether DMSO can be assumed to be an inert co-solvent. The influence of DMSO on the production of extracellular enzymes by Pleurotus ostreatus was investigated. DMSO functioned as either an inducer or a repressor, depending on the enzyme studied. The production of laccase and endo-1,4-beta-xylanase increased by 29 and 250%, respectively, in presence of DMSO. However, DMSO repressed the activities of manganese peroxidase, beta-glucosidase, beta-xylanase, and endo-1,4-beta-glucanase by 30, 33, 99 and 16%, respectively. These results raise concerns about the interpretation of bioactivity measurements when DMSO is assumed to function as an inert co-solvent to solubilize water-insoluble molecules.Biotechnology Letters 06/2006; 28(9):651-5. · 1.68 Impact Factor -
Article: Sophorolipids block lethal effects of septic shock in rats in a cecal ligation and puncture model of experimental sepsis.
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ABSTRACT: Sophorolipids, a family of natural and easily chemoenzymatically modified microbial glycolipids, are promising modulators of the immune response. The potential of the therapeutic effect of sophorolipids was investigated in vivo in a rat model of sepsis and in vitro by analysis of nitric oxide and cytokine production. Prospective, randomized animal study. Experimental laboratory. Male Sprague-Dawley rats, 200-240 g. Intra-abdominal sepsis was induced in vivo in 166 rats via cecal ligation and puncture (CLP); 60 rats were used to characterize the model. The remaining rats were treated with sophorolipids or vehicle (dimethylsulfoxide [DMSO]/physiologic saline) by intravenous (iv) tail vein or intraperitoneal (IP) injection immediately post-CLP (25/group). Survival rates were compared at 36 hrs after surgery. In vitro, macrophages were cultured in lipopolysaccharide (LPS) +/- sophorolipid and assayed for nitric oxide (NO) production and gene expression profiles of inflammatory cytokines. In addition, splenic lymphocytes isolated from CLP rats +/- sophorolipid treatment (three per group) were analyzed for cytokine production by RNase protection assay. CLP with 16-gauge needles optimized sepsis induction and resultant mortality. Sophorolipid treatment improved rat survival by 34% (iv) and 14% (IP) in comparison with vehicle controls (p < .05 for iv treatment). Sophorolipids decreased LPS-induced macrophage NO production by 28% (p < .05). mRNA expression of interleukin (IL)-1beta was downregulated by 42.5 +/- 4.7% (p < .05) and transforming growth factor (TGF)-beta1 was upregulated by 11.7 +/- 1.5% (p < .05) in splenocytes obtained 6 hrs postsophorolipid treatment. LPS-treated macrophages cultured 36 hrs with sophorolipids showed increases in mRNA expression of IL-1alpha (51.7%), IL-1beta (31.3%), and IL-6 (66.8%) (p < .05). Administration of sophorolipids after induction of intra-abdominal sepsis significantly decreases mortality in this model. This may be mediated in part by decreased macrophage NO production and modulation of inflammatory responses.Critical Care Medicine 02/2006; 34(1):188-95. · 6.33 Impact Factor -
Article: Sophorolipids, microbial glycolipids with anti-human immunodeficiency virus and sperm-immobilizing activities.
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ABSTRACT: The increased incidence of human immunodeficiency virus (HIV)/AIDS disease in women aged 15 to 49 years has identified the urgent need for a female-controlled, efficacious, and safe vaginal topical microbicide. To meet this challenge, sophorolipid (SL) produced by Candida bombicola and its structural analogs have been studied in this report for their spermicidal, anti-HIV, and cytotoxic activities. The sophorolipid diacetate ethyl ester derivative is the most potent spermicidal and virucidal agent of the series of SLs studied. Its virucidal activity against HIV and sperm-immobilizing activity against human semen are similar to those of nonoxynol-9. However, it also induced enough vaginal cell toxicity to raise concerns about its applicability for long-term microbicidal contraception. Its structure-activity relationship has been established for creating new analogs with less cytotoxicity and higher activity.Antimicrobial Agents and Chemotherapy 11/2005; 49(10):4093-100. · 4.84 Impact Factor -
Article: Supramolecular assemblies of a naturally derived sophorolipid.
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ABSTRACT: Acidic sophorolipid (SL) molecules derived from yeasts represent a novel type of asymmetrical bolaamphiphiles due to their unique structural features that include an asymmetrical polar head size (disaccharide vs COOH), a kinked hydrophobic core (cis-9-octadecenoic chain), and a non-amide polar-nonpolar linkage. Light microscopy, small- and wide-angle X-ray scattering, FT-IR spectroscopy, and dynamic laser light scattering were used to investigate the supramolecular structures of the self-assembled aggregates of SL molecules at different pH values. In acidic conditions (pH < 5.5), giant twisted and helical ribbons of 5-11 microm width and several hundreds of micrometers length were observed for the first time. Increase in solution pH values slowed ribbon formation, decreased ribbon yield, and increased the helicity and entanglements of the giant ribbons. An interdigitated lamellar packing model of acidic SL-COOH molecules with a long period of 2.78 nm, stabilized by both the strong hydrophobic association between the cis-9-octadecenoic chains and strong disaccharide-disaccharide hydrogen bonding, is proposed. The neutralization of SL-COOH in water to SL-COONa produced clear solutions with the formation of short-range ordered aggregates. At concentrations below 1.0 mg/mL, the size of self-assembled aggregates increased as the concentration increased. At concentrations above 1.0 mg/mL, narrowly distributed micellar aggregates with a constant hydrodynamic radius (R(h)) of about 100 nm are formed. The large micelles show strong angular dependence with the fast mode appearing at scattering angle theta >/= 60 degrees.Langmuir 09/2004; 20(19):7926-32. · 4.19 Impact Factor
Top co-authors
Top Journals
Institutions
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2006–2012
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Dowling College
- Department of Biology
New York City, NY, USA
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2000–2012
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Sardar Patel University
Vallabh Vidyanagar, State of Gujarat, India
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2002–2005
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City University of New York - Brooklyn College
Brooklyn, NY, USA
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2004
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City University of New York - College of Staten Island
New York City, NY, USA
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