The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Ashraf S Ibrahim - One of the best experts on this subject based on the ideXlab platform.
-
prophylactic treatment with vt 1161 protects immunosuppressed mice from Rhizopus arrhizus var arrhizus infection
Antimicrobial Agents and Chemotherapy, 2017Co-Authors: Teclegiorgis Gebremariam, Nathan P Wiederhold, Edward P Garvey, William J Hoekstra, Robert J Schotzinger, Thomas F Patterson, Scott G Filler, Sondus Alkhazraji, Ashraf S IbrahimAbstract:Author(s): Gebremariam, Teclegiorgis; Alkhazraji, Sondus; Lin, Lin; Wiederhold, Nathan P; Garvey, Edward P; Hoekstra, William J; Schotzinger, Robert J; Patterson, Thomas F; Filler, Scott G; Ibrahim, Ashraf S | Abstract: We compared prophylactic or continuous therapy with the investigational drug VT-1161 to that with posaconazole in treating murine mucormycosis due to Rhizopus arrhizus var. arrhizus In the prophylaxis studies, only VT-1161 resulted in improved survival and lowered tissue fungal burden of immunosuppressed infected mice. In the continuous therapy, VT-1161 outperformed posaconazole in prolonging mouse survival time despite its comparable effect in lowering tissue fungal burden. These results support the further development of VT-1161 against mucormycosis.
-
vt 1161 protects immunosuppressed mice from Rhizopus arrhizus var arrhizus infection
Antimicrobial Agents and Chemotherapy, 2015Co-Authors: Teclegiorgis Gebremariam, Nathan P Wiederhold, Annette W Fothergill, Edward P Garvey, William J Hoekstra, Robert J Schotzinger, Thomas F Patterson, Scott G Filler, Ashraf S IbrahimAbstract:We studied the efficacy of the investigational drug VT-1161 against mucormycosis. VT-1161 had more potent in vitro activity against Rhizopus arrhizus var. arrhizus than against R. arrhizus var. delemar. VT-1161 treatment demonstrated dose-dependent plasma drug levels with prolonged survival time and lowered tissue fungal burden in immunosuppressed mice infected with R. arrhizus var. arrhizus and was as effective as high-dose liposomal amphotericin B treatment. These results support further development of VT-1161 against mucormycosis.
John M. Tobin - One of the best experts on this subject based on the ideXlab platform.
-
reactive dye biosorption by Rhizopus arrhizus biomass
Enzyme and Microbial Technology, 2002Co-Authors: T Omahony, Eric Guibal, John M. TobinAbstract:The biosorption of three commonly used reactive dyes, from aqueous solutions by oven-dried Rhizopus arrhizus biomass was studied in a batch system with respect to pH, initial dye concentration and initial metal ion concentration. The biomass exhibited maximum dye uptake at pH 2 due to its positively charged nature at acidic pH and the anionic nature of the reactive dyes. Reactive orange 16 dye was adsorbed most effectively to a maximum of approximately 200 mg/g. The presence of high levels of cadmium did not significantly impair the adsorption capacity of the biomass. Dye removal from a multicomponent solution of all three dyes was also achieved. Rhizopus biomass was found to exhibit superior removal properties than activated charcoal.
-
Reactive dye biosorption by Rhizopus arrhizus biomass
Enzyme and Microbial Technology, 2002Co-Authors: Tom O'Mahony, Eric Guibal, John M. TobinAbstract:The biosorption of three commonly used reactive dyes, from aqueous solutions by oven-dried Rhizopus arrhizus biomass was studied in a batch system with respect to pH, initial dye concentration and initial metal ion concentration. The biomass exhibited maximum dye uptake at pH 2 due to its positively charged nature at acidic pH and the anionic nature of the reactive dyes. Reactive orange 16 dye was adsorbed most effectively to a maximum of approximately 200mg/g. The presence of high levels of cadmium did not significantly impair the adsorption capacity of the biomass. Dye removal from a multicomponent solution of all three dyes was also achieved. Rhizopus biomass was found to exhibit superior removal properties than activated charcoal. © 2002 Elsevier Science Inc. All rights reserved.
-
adsorption of metal ions by Rhizopus arrhizus biomass characterization studies
Enzyme and Microbial Technology, 1994Co-Authors: Joseph M Brady, John M. TobinAbstract:Freeze-dired, oven-dried, and nonmetabolizing live Rhizopus arrhizus biomass were tested for their capacity to adsorb the test ions, Sr2+, cd2+, and Cu2+, over the pH range 4–6. Metal uptake values for each biomass type were found to increase in the order Cu2+ > Cd2+ > Sr2+. Freeze-dried biomass proved to be the most efficient biomass type for metal adsorption, followed in order by oven-dried and live biomass for Sr2+ systems, and live and oven-dried biomass for Cd2+ and Cu2+ systems. Each test ion displaced constant levels of Ca2+ and Mg2+ ions from the three biomass types, indicating that biomass pretreatment had no apparent effect on the ion-exchange capacity of Rhizopus arrhizus. Similarly, the levels of H+ displacement resulting from test ion adsorption were unaffected by pretreatment but were found to increase in the order Cu2+ > Cd2+ > Sr2+. Linear reciprocal Langmuir and Scatchard transformation plots reflected the predominantly ion-exchange mechanism of Sr2+ and Cd2+ adsorption, and a curved Scatchard transformation plot reflected the more covalent nature of Cu2+ adsorption.
-
immobilisation protocols and effects on cadmium uptake by Rhizopus arrhizus biosorbents
Biotechnology Techniques, 1993Co-Authors: John M. Tobin, B Lhomme, J C RouxAbstract:Protocols were developed for the immobilisation of Rhizopus arrhizus biomass using alginate, polyacrylamide, epoxy resin and polyvinylformal materials and the resulting biosorbents were tested for the removal of cadmium from solution. Polyvinyl formal immobilisation produced the optimal biosorbent with cell loadings of up to 80% and metal adsorption capacities of 84% of that of free biomass.
Subrata Chattopadhyay - One of the best experts on this subject based on the ideXlab platform.
-
biosorption of azo dyes by spent Rhizopus arrhizus biomass
Applied Water Science, 2017Co-Authors: Neeta A Salvi, Subrata ChattopadhyayAbstract:In the present study, spent Rhizopus arrhizus biomass was used for the removal of six azo dyes from aqueous solutions. The dye removal capacity of the biomass was evaluated by conducting batch tests as a function of contact time, biomass dosage, pH and initial dye concentrations. The pseudo-second-order kinetic model fitted well with the experimental data with correlation coefficients greater than 0.999, suggesting that chemisorptions might be the rate limiting step. The equilibrium sorption data showed good fit to the Langmuir isotherm model. Among the six dyes tested, the maximum monolayer adsorption capacity for fast red A and metanil yellow was found to be 108.8 and 128.5 mg/g, respectively. These encouraging results suggest that dead Rhizopus arrhizus biomass could be a potential biomaterial for the removal of azo dyes from aqueous dye solution.
-
laboratory scale up synthesis of chiral carbinols using Rhizopus arrhizus
Tetrahedron-asymmetry, 2016Co-Authors: Neeta A Salvi, Subrata ChattopadhyayAbstract:Abstract Rhizopus arrhizus mediated bioreduction was optimized using acetophenone as a model substrate. Various parameters such as bio-processing conditions, reaction time, substrate concentration, temperature, and solvent carrier were studied. This optimized protocol was further exploited for scaled up bioreductions of various prochiral ketones. This study demonstrates the versatility of the fungus Rhizopus arrhizus as a biocatalyst to obtain chiral carbinols in good to excellent yields and selectivities.
-
Modified Rhizopus arrhizus biomass for sorption of 241Am and other radionuclides
Journal of Radioanalytical and Nuclear Chemistry, 2010Co-Authors: Subhash Chandra Tripathi, Neeta A Salvi, P S Dhami, R Kannan, P. W. Naik, S. K. Munshi, Subrata ChattopadhyayAbstract:The improvement and the refinement of non-viable Rhizopus arrhizus biomass were investigated via immobilization. Immobilization was carried out by using sodium alginate/CaCl2 solution and formaldehyde/HCl cross-linking with dead Rhizopus arrhizus biomass and were used for the sorption of radionuclides from low level effluent wastes. The sodium alginate/CaCl2 immobilized biomass (ratio 1:2) showed about 86% sorption for 241Am activity but due to its soft nature and tendency to undergo distortion in shape, is unsuitable for practical applications. The biomass cross-linked with 15% formaldehyde/0.1 M HCl solution has a relatively high mechanical strength and rigidity. It was showing a sorption of >99% for 241Am activity and has the sorption capacity of ~65 mg/g for americium and uranium. Hence, it can be utilized for the removal of radionuclides from radioactive waste effluents.
-
asymmetric reduction of halo substituted arylalkanones with Rhizopus arrhizus
Tetrahedron-asymmetry, 2008Co-Authors: Neeta A Salvi, Subrata ChattopadhyayAbstract:The Rhizopus arrhizus-mediated asymmetric reduction of various haloaryl alkanones furnished the respective (S)-carbinols with good to excellent enantioselectivities. It was found that the reaction course was primarily governed by the relative position of the halogen with respect to the carbonyl group, and its size. The relative order of efficacies of the nature of the halogen and their substitution pattern were Br > Cl > F and o- > p- > m-. The ortho-effect was the most predominant factor in the stereochemical outcome of the reaction, which was also confirmed with some non-halo-substituted acetophenones.
-
Rhizopus arrhizus mediated asymmetric reduction of alkyl 3 oxobutanoates
Tetrahedron-asymmetry, 2004Co-Authors: Neeta A Salvi, Subrata ChattopadhyayAbstract:Alkyl 3-oxobutanoates (alkyl: methyl, ethyl, allyl, isobutyl, t-butyl) were reduced enantioselectively to the corresponding (S)-alcohols by the fungus Rhizopus arrhizus and other Rhizopus sp. The best result obtained was with t-butyl 3-oxobutanoate, which was reduced by R. arrhizus with 99% enantiomeric excess and ∼68% isolated yield.
Scott G Filler - One of the best experts on this subject based on the ideXlab platform.
-
prophylactic treatment with vt 1161 protects immunosuppressed mice from Rhizopus arrhizus var arrhizus infection
Antimicrobial Agents and Chemotherapy, 2017Co-Authors: Teclegiorgis Gebremariam, Nathan P Wiederhold, Edward P Garvey, William J Hoekstra, Robert J Schotzinger, Thomas F Patterson, Scott G Filler, Sondus Alkhazraji, Ashraf S IbrahimAbstract:Author(s): Gebremariam, Teclegiorgis; Alkhazraji, Sondus; Lin, Lin; Wiederhold, Nathan P; Garvey, Edward P; Hoekstra, William J; Schotzinger, Robert J; Patterson, Thomas F; Filler, Scott G; Ibrahim, Ashraf S | Abstract: We compared prophylactic or continuous therapy with the investigational drug VT-1161 to that with posaconazole in treating murine mucormycosis due to Rhizopus arrhizus var. arrhizus In the prophylaxis studies, only VT-1161 resulted in improved survival and lowered tissue fungal burden of immunosuppressed infected mice. In the continuous therapy, VT-1161 outperformed posaconazole in prolonging mouse survival time despite its comparable effect in lowering tissue fungal burden. These results support the further development of VT-1161 against mucormycosis.
-
vt 1161 protects immunosuppressed mice from Rhizopus arrhizus var arrhizus infection
Antimicrobial Agents and Chemotherapy, 2015Co-Authors: Teclegiorgis Gebremariam, Nathan P Wiederhold, Annette W Fothergill, Edward P Garvey, William J Hoekstra, Robert J Schotzinger, Thomas F Patterson, Scott G Filler, Ashraf S IbrahimAbstract:We studied the efficacy of the investigational drug VT-1161 against mucormycosis. VT-1161 had more potent in vitro activity against Rhizopus arrhizus var. arrhizus than against R. arrhizus var. delemar. VT-1161 treatment demonstrated dose-dependent plasma drug levels with prolonged survival time and lowered tissue fungal burden in immunosuppressed mice infected with R. arrhizus var. arrhizus and was as effective as high-dose liposomal amphotericin B treatment. These results support further development of VT-1161 against mucormycosis.
Teclegiorgis Gebremariam - One of the best experts on this subject based on the ideXlab platform.
-
prophylactic treatment with vt 1161 protects immunosuppressed mice from Rhizopus arrhizus var arrhizus infection
Antimicrobial Agents and Chemotherapy, 2017Co-Authors: Teclegiorgis Gebremariam, Nathan P Wiederhold, Edward P Garvey, William J Hoekstra, Robert J Schotzinger, Thomas F Patterson, Scott G Filler, Sondus Alkhazraji, Ashraf S IbrahimAbstract:Author(s): Gebremariam, Teclegiorgis; Alkhazraji, Sondus; Lin, Lin; Wiederhold, Nathan P; Garvey, Edward P; Hoekstra, William J; Schotzinger, Robert J; Patterson, Thomas F; Filler, Scott G; Ibrahim, Ashraf S | Abstract: We compared prophylactic or continuous therapy with the investigational drug VT-1161 to that with posaconazole in treating murine mucormycosis due to Rhizopus arrhizus var. arrhizus In the prophylaxis studies, only VT-1161 resulted in improved survival and lowered tissue fungal burden of immunosuppressed infected mice. In the continuous therapy, VT-1161 outperformed posaconazole in prolonging mouse survival time despite its comparable effect in lowering tissue fungal burden. These results support the further development of VT-1161 against mucormycosis.
-
vt 1161 protects immunosuppressed mice from Rhizopus arrhizus var arrhizus infection
Antimicrobial Agents and Chemotherapy, 2015Co-Authors: Teclegiorgis Gebremariam, Nathan P Wiederhold, Annette W Fothergill, Edward P Garvey, William J Hoekstra, Robert J Schotzinger, Thomas F Patterson, Scott G Filler, Ashraf S IbrahimAbstract:We studied the efficacy of the investigational drug VT-1161 against mucormycosis. VT-1161 had more potent in vitro activity against Rhizopus arrhizus var. arrhizus than against R. arrhizus var. delemar. VT-1161 treatment demonstrated dose-dependent plasma drug levels with prolonged survival time and lowered tissue fungal burden in immunosuppressed mice infected with R. arrhizus var. arrhizus and was as effective as high-dose liposomal amphotericin B treatment. These results support further development of VT-1161 against mucormycosis.