@article { ISI:000232157000036, title = {Cloning, preparation and preliminary crystallographic studies of penicillin V acylase autoproteolytic processing mutants}, journal = {Acta Crystallographica Section F-Structural Biology and Crystallization Communications}, volume = {61}, number = {1}, year = {2005}, month = {JAN}, pages = {124-127}, publisher = {BLACKWELL PUBLISHING}, type = {Article}, address = {9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND}, issn = {1744-3091}, doi = {10.1107/S1744309104031227}, author = {Chandra, P. M. and Brannigan, James A. and Prabhune, Asmita and Pundle, A. and Turkenburg, J. P. and Dodson, Guy G. and Suresh, C. G.} } @article { ISI:000232320400015, title = {Cloning, purification, crystallization and preliminary structural studies of penicillin V acylase from Bacillus subtilis}, journal = {Acta Crystallographica Section F-Structural Biology Communications}, volume = {61}, number = {7}, year = {2005}, month = {JUL}, pages = {680-683}, publisher = {INT UNION CRYSTALLOGRAPHY}, type = {Article}, address = {2 ABBEY SQ, CHESTER, CH1 2HU, ENGLAND}, abstract = {

{Penicillin acylase proteins are amidohydrolase enzymes that cleave penicillins at the amide bond connecting the side chain to their beta-lactam nucleus. An unannotated protein from Bacillus subtilis has been expressed in Escherichia coli, purified and confirmed to possess penicillin V acylase activity. The protein was crystallized using the hanging-drop vapour-diffusion method from a solution containing 4 M sodium formate in 100 mM Tris-HCl buffer pH 8.2. Diffraction data were collected under cryogenic conditions to a spacing of 2.5 A. The crystals belonged to the orthorhombic space group C222(1), with unit-cell parameters a = 111.0

}, issn = {2053-230X}, author = {Rathinaswamy, P. and Pundle, A. V. and Prabhune, Asmita and SivaRaman, H. and Brannigan, James A. and Dodson, Guy G. and Suresh, C. G.} } @article { ISI:000246341400004, title = {Cephalexin-mediated synthesis of quasi-spherical and anisotropic gold nanoparticles and their in situ capping by the antibiotic}, journal = {Journal of Physical Chemistry C }, volume = {111}, number = {19}, year = {2007}, month = {MAY}, pages = {6933-6938}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Here we report, for the first time, synthesis of gold nanostructures in aqueous medium by reducing gold ions using cephalexin, a potent broad-spectrum antibiotic, where the morphology of the gold nanoparticles is found to be dependent on the concentration of chloroauric acid. The characterization techniques indicate that particle surfaces are coated with the robust layer of the antibiotic making them stable for a long time. Thus, cephalexin acts as both the reducing and the capping agent. NMR and XPS analysis indicate that the sulfur moiety is responsible for the reduction and binding process.

}, issn = {1932-7447}, doi = {10.1021/jp067645r}, author = {Jagannathan, Ramya and Poddar, Pankaj and Prabhune, Asmita} } @article { ISI:000258819000009, title = {Characterization of smallest active monomeric penicillin V acylase from new source: a yeast, rhodotorula aurantiaca (NCIM 3425)}, journal = {Process Biochemistry}, volume = {43}, number = {9}, year = {2008}, month = {SEP}, pages = {961-967}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

An intracellular monomeric penicillin V acylase (PVA) of 36,000 Da exhibiting pI of 4.19, purified from newly identified yeast source, Rhodotorula aurantiaca (NCIM 3425). The enzyme was purified by hydrophobic interaction chromatography. The enzyme showed optimal activity at 45 degrees C and retained 80\% activity after incubation at 45 degrees C and pH 5.5 for I h. The enzyme showed maximum activity at pH 5.5 and was very stable between pH 5.5-6.5 with optimum stability at pH 6.0. It exhibited 50\% of its original activity after 30 min incubation at 60 degrees C. Enzyme hydrolyzed substrates with benzyl side chain but preferred penicillin V as primary substrate. N-terminally located serine supports the fact that it belongs to Ntn (N-terminal nucleophile)-hydrolase superfamily. The initial ten amino acid residues of R. aurantiaca PVA were identical to the initial sequence of NADH dehydrogenase (EC 1.6.99.3): however the enzyme lacks dehydrogenase activity. EGTA, EDTA, hexane and ethyl acetate stabilized the activity where as small chain alcohols inhibited it. 1,4-Dioxane, THF (tetrahydrofurane), phenol and benzyl alcohol severely inhibited enzyme activity while BME and DTT increased it. Tween 80 and Tween 20 highly enhanced the activity where as SIDS and Triton X-100 inhibited it. (C) 2008 Elsevier Ltd. All rights reserved.

}, keywords = {Intracellular enzyme, N-terminal sequencing, Penicillin V acylase, Purification, Rhodotorula aurantiaca, Substrate specificity}, issn = {1359-5113}, doi = {10.1016/j.procbio.2008.04.024}, author = {Kumar, Atul and Prabhune, Asmita and Suresh, C. G. and Pundle, Archana} } @conference { ISI:000271775103415, title = {COLL 41-studies in biosurfactants: sophorolipids}, booktitle = { 235th American-Chemical-Society National Meeting}, volume = {235}, year = {2008}, note = {235th American-Chemical-Society National Meeting, New Orleans, LA, APR 06-10, 2008}, month = {APR}, pages = {Meeting Abstract : 41 - Coll}, publisher = {American Chemical Society}, organization = {American Chemical Society}, type = {Meeting Abstract}, address = {1155 16th ST, NW, Washington, DC 20036 USA}, keywords = {Biosurfactants, Candida bombicola ATCC 22214, Fermentation Process, sophorolipids}, issn = {0065-7727}, author = {Momin, Shamim A. and Prabhune, Asmita and Sonchal, Bhushan P. and Shah, Sachin and Kothekar, Shrinivas C.} } @article { ISI:000276973200011, title = {Continuous flow synthesis of functionalized silver nanoparticles using bifunctional biosurfactants}, journal = {Green Chemistry}, volume = {12}, number = {4}, year = {2010}, month = {APR}, pages = {609-615}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Silver nanoparticles were synthesized by continuous flow methods using biosurfactants, namely, oleic acid sophorolipid (OASL) and stearic acid sophorolipid (SASL). Both the sophorolipids can act as reducing and capping agents. The effect of temperature on the completion of nanoparticle formation and the particle growth dynamics (size) were studied in batch mode. While the completion of the reaction using oleic acid sophorolipid needed 20 min, only 5 min were required with the stearic acid sophorolipid as capping and reducing agent. Hence all the continuous flow experiments were carried out using the stearic acid sophorolipid. The continuous flow synthesis of silver nanoparticles was carried out in a stainless steel helical coil and also in a spiral polymeric minichannel reactor. The DLS results show that higher flow rate leads to the formation of bigger and polydisperse particles because of incomplete reactions. Higher residence time allowed the completion of reaction leading to spherical, small and monodisperse particles.

}, issn = {1463-9262}, doi = {10.1039/b919550e}, author = {Kumar, D. V. Ravi and Kasture, Manasi and Prabhune, Asmita and Ramana, C. V. and Bhagavatula L. V. Prasad and Kulkarni, A. A.} } @article { ISI:000274207800015, title = {Cytotoxic and genotoxic assessment of glycolipid-reduced and -capped gold and silver nanoparticles}, journal = {New Journal of Chemistry}, volume = {34}, number = {2}, year = {2010}, month = {NOV}, pages = {294-301}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A systematic cytotoxic and genotoxic evaluation of glycolipid-conjugated silver and gold nanoparticles is carried out. These glycolipid nanoparticle conjugates are obtained by exploiting the reductive capability of a class of glycolipids called sophorolipids that play the role of capping agent as well. Further, when tested for their cytotoxicity and genotoxicity on HepG2 cells, these nanoparticles are found to be cytocompatible up to 100 mu M metal concentrations. Of the two metallic systems investigated, gold nanoparticles are found to be more cytocompatible than the same concentrations of silver nanoparticles. Similarly, it is also demonstrated that at 100 mu M, silver nanoparticles cause more DNA damage compared to gold nanoparticles of similar concentrations.

}, issn = {1144-0546}, doi = {10.1039/b9nj00277d}, author = {Singh, Sanjay and D{\textquoteright}Britto, Virginia and Prabhune, Asmita and Ramana, C. V. and Dhawan, Alok and Bhagavatula L. V. Prasad} } @article { ISI:000287363500022, title = {Cytotoxicity of sophorolipid-gellan gum-gold nanoparticle conjugates and their doxorubicin loaded derivatives towards human glioma and human glioma stem cell lines}, journal = {Nanoscale}, volume = {3}, number = {2}, year = {2011}, month = {JAN}, pages = {575-580}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Biocompatible gold nanoparticles were synthesized by using a naturally occurring gum-Gellan Gum-as a capping and reducing agent. These were further conjugated with sophorolipids which again were accessed through a biochemical transformation of a fatty acid. The cellular uptake of sophorolipid-conjugated gellan gum reduced gold nanoparticles and their cytotoxicity on human glioma cell line LN-229 and human glioma stem cell line HNGC-2 were investigated. Quite surprisingly even the simple sophorolipid-conjugated gellan gum reduced/capped gold nanoparticles showed greater efficacy in killing the glioma cell lines and, gratifyingly, the glioma stem cell lines also. The cytotoxic effects became more prominent once the anti cancer drug doxorubicin hydrochloride was also conjugated to these gold nanoparticles.

}, issn = {2040-3364}, doi = {10.1039/c0nr00598c}, author = {Dhar, Sheetal and Reddy, E. Maheswara and Prabhune, Asmita and Pokharkar, Varsha and Shiras, Anjali and Bhagavatula L. V. Prasad} } @article { ISI:000302770700013, title = {Characterization of smallest active monomeric lipase from novel rhizopus strain: application in transesterification}, journal = {Applied Biochemistry and Biotechnology}, volume = {166}, number = {7}, year = {2012}, month = {APR}, pages = {1769-1780}, publisher = {HUMANA PRESS INC}, address = {999 RIVERVIEW DRIVE SUITE 208, TOTOWA, NJ 07512 USA}, abstract = {

An extracellular lipase-producing fungus was isolated from oil-rich soil. This fungus belongs to the genus Rhizopus and clades with Rhizopus oryzae. Lipase was purified to homogeneity from this novel fungal source using ammonium sulphate precipitation followed by Q-Sepharose chromatography. The extracellular lipase was purified 8.6-fold, and enzymatic properties were studied. The molecular mass of the purified enzyme was estimated to be 17 kD by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and 16.25 kD by matrix-assisted laser desorption ionization/time-of-flight analysis. The native molecular mass was estimated to be 17.5 kD by gel filtration, indicating the protein to be monomer. The optimum pH and temperature for the enzyme catalysis were 7.0 A degrees C and 40 A degrees C, respectively. Enzyme was stable in pH range 6.0-7.0 and retains 95-100\% activity when incubated at 50 A degrees C for 1 h. The pI of the purified lipase was 4.2. Enzyme was stable in the organic solvents such as ethanol, hexane and methanol for 2 h. Purified enzyme was used for transesterification of oleic acid in the presence of ethanol for production of oleic acid ethyl ester with a conversion efficiency of 66\% after 24 h at 30 A degrees C.

}, keywords = {Lipase, Low molecular weight, Purification, Rhizopus, transesterification}, issn = {0273-2289}, doi = {10.1007/s12010-012-9584-0}, author = {Kantak, Jayshree B. and Prabhune, Asmita} } @article { ISI:000301921300006, title = {Crystallization and X-ray structure analysis of a thermostable penicillin G acylase from alcaligenes faecalis}, journal = {Acta Crystallographica Section F-Structural Biology and Crystallization Communications}, volume = {68}, number = {3}, year = {2012}, month = {MAR}, pages = {273-277}, publisher = {WILEY-BLACKWELL}, address = {COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA}, abstract = {

{The enzyme penicillin G acylase (EC 3.5.1.11) catalyzes amide-bond cleavage in benzylpenicillin (penicillin G) to yield 6-aminopenicillanic acid, an intermediate chemical used in the production of semisynthetic penicillins. A thermostable penicillin G acylase from Alcaligenes faecalis (AfPGA) has been crystallized using the hanging-drop vapour-diffusion method in two different space groups: C2221, with unit-cell parameters a = 72.9

}, keywords = {calcium binding, disulfide bridges, Ntn hydrolases, orthorhombic form, tetragonal form, Thermostability}, issn = {1744-3091}, doi = {10.1107/S1744309111053930}, author = {Varshney, Nishant Kumar and Kumar, R. Suresh and Ignatova, Zoya and Prabhune, Asmita and Pundle, Archana and Dodson, Eleanor J. and Suresh, C. G.} } @article { ISI:000326056600165, title = {Chemically conjugated sophorolipids on CdTe QDs: a biocompatible photoluminescence nanocomposite for theranostic applications}, journal = {RSC Advances}, volume = {3}, number = {44}, year = {2013}, month = {SEP}, pages = {22319-22325}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Functional nontoxic cadmium telluride (CdTe) quantum dots (QDs) have been synthesized using a natural functional glycolipid belonging to the family of sophorolipids (SL) as a surface-modifying agent. These SLs with open acidic form are highly suitable for QDs stabilization, are readily obtained by a fermentation process of the yeast Candida bombicola (polymorph Starmerella bombicola) in large amounts. In this work chemically stable, water soluble, and photoluminescent CdTe QDs were successfully conjugated to sophorolipids via a cross-linking reaction. The formation of SLs conjugated CdTe QDs was confirmed using different analytical techniques X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), Electron Diffraction (ED), Atomic Force Microscopy (AFM), Dynamic Light Scattering (DLS), and Photoluminescence (PL). It was shown that after being conjugated with SL the SL-CdTe QDs becomes biocompatible, still maintaining its water solubility and photoluminescence properties. The final SL coated photoluminescent CdTe QDs represent interesting biocompatible materials potentially useful for biomedical applications.

}, issn = {2046-2069}, doi = {10.1039/c3ra44535f}, author = {Singh, Pooja and Joshi, Kasturi and Guin, Debanjan and Prabhune, Asmita} } @article { ISI:000316341000001, title = {Crystalline xylitol production by a novel yeast, pichia caribbica (HQ222812), and its application for quorum sensing inhibition in gram-negative marker strain chromobacterium violaceum CV026}, journal = {Applied Biochemistry and Biotechnology}, volume = {169}, number = {6}, year = {2013}, month = {MAR}, pages = {1753-1763}, publisher = {HUMANA PRESS INC}, address = {999 RIVERVIEW DRIVE SUITE 208, TOTOWA, NJ 07512 USA}, abstract = {

Xylitol, a sugar alcohol, is fast gaining ground over other artificial sugar substitutes owing to its advantageous properties. Xylitol is a safer alternative for diabetics because of insulin-independent metabolism. It has beneficial properties suitable to form an important part of odontological formulations. Conventional commercial production of xylitol involves harsh chemical method operating at high temperature and pressure. Thus, microbial production of xylitol is preferred over chemical method, and yeasts have been extensively exploited for this purpose. In the present manuscript, quantitative production of xylitol from d-xylose with the yield of 0.852 gm/gm and volumetric productivity of 1.83 gm/l/h in crystalline form, using novel yeast Pichia caribbica is reported. Also, a mild, safe procedure for product extraction is described. The ability of xylitol to act as a quorum sensing antagonist in gram-negative marker strain Chromobacterium violaceum CV026 has been demonstrated for the first time.

}, keywords = {Crystallization, CV026, Pichia caribbica, Quorum sensing antagonist, xylitol}, issn = {0273-2289}, doi = {10.1007/s12010-012-0039-4}, author = {Mukherji, Ruchira and Joshi-Navare, Kasturi and Prabhune, Asmita} } @article { ISI:000330489500002, title = {Controlled release of antimicrobial Cephalexin drug from silica microparticles}, journal = {Materials Science \& Engineering C-Materials for Biological Applications}, volume = {34}, year = {2014}, month = {JAN}, pages = {9-14}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Release of antimicrobial drugs in a controlled fashion for extended duration of time has been investigated for long. Such controlled-drug-releasing materials show promising applications in medicinal bandages. Along with antimicrobial agents, one could also incorporate other therapeutic drugs, to make such bandages more versatile. In this context, silica micro particles were synthesized using direct reduction method, in which the synthesis was done in the presence of Cephalexin. Cephalexin was chosen as an antimicrobial candidate. The morphological characterization shows formation of monodispersed, silica microparticles of similar to 200 nm in size. The FTIR spectroscopy shows weak interaction of the drug molecule at its hydroxide (OH) site with oxygen ions on the silica surface. Upon conjugation, the UV-vis spectroscopy shows persistence of the Cephalexin signature, especially its R group, confirming its antimicrobial activity even after conjugation. Loading studies reveal 12\% Cephalexin loading on silica. The antimicrobial studies were done on three micro-organisms, namely, Staphylococcus aureus, Bacillus subtilis and Escherichia coli. Using zone-of-inhibition studies, it was found that E. coli, did not respond to the delivery of Cephalexin either directly or via microparticles. However, for both S. aureus and B. subtilis, the particles showed controlled release of Cephalexin for the duration of 48 h and continued maintenance and even increase in the zone of inhibition. This work demonstrates an effective protocol to prepare antimicrobial patches for controlled drug delivery. (C) 2013 Elsevier B.V. All rights reserved.

}, keywords = {Antimicrobial, Medicinal bandage, Silica microparticles, sustained drug release}, issn = {0928-4931}, doi = {10.1016/j.msec.2013.10.002}, author = {Rao, B. V. Bhaskara and Mukherji, Ruchira and Shitre, G. and Alam, F. and Prabhune, Asmita and Kale, Sangeeta N.} }