02718nas a2200265   4500008004100000022001400041245018300055210006900238260007700307300001400384490000600398520169400404653001702098653001902115653001802134653002402152653001102176100002302187700001802210700003002228700002302258700001902281700002402300856012802324       2008                        eng d  a1439-422700aExtracellular synthesis of crystalline silver nanoparticles and molecular evidence of silver resistance from morganella sp.: towards understanding biochemical synthesis mechanism0 aExtracellular synthesis of crystalline silver nanoparticles and   aPO BOX 10 11 61, D-69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcJUN  a1415-14220 v93 a<p>There has been significant progress in the biological synthesis of nanomaterials. However, the molecular mechanism of synthesis of such bio-nanomaterials remains largely unknown. Here, we report the extracellular synthesis of crystalline silver nanoparticles (AgNPs) by using Morganella sp., and show molecular evidence I of silver resistance by elucidating the synthesis mechanism. The AgNPs were 20 +/- 5 nm in diameter and were highly stable at 1 room temperature. The kinetics of AgNPs formation was investigated. Detectable particles were formed after on hour of reaction, and their production remained exponential up to 18 h, and saturated at 24 h. Morganella sp. was found to be highly resistant to silver cations and was able to grow in the presence of more than 0.5 mm AgNO3. Three gene homologues viz. silE, silP and silS were identified in silver-resistant Morganella sp. The homologue of silE from Morganella sp. showed 99% nucleotide sequence similarity with the previously reported gene, silE, which encodes a periplasmic silver-binding protein. The homologues of silP and silS were also highly similar to previously reported sequences. Similar activity was totally absent in closely related Escherichia coli; this suggests that a unique mechanism of extracellular AgNPs synthesis is associated with silver-resistant Morganella sp. The molecular mechanism of silver resistance and its gene products might have a key role to play in the overall synthesis process of AgNPs by Morganella sp. An understanding of such biochemical mechanisms at the molecular level might help in developing an ecologically friendly and cost-effective protocol for microbial AgNPs synthesis.</p>10aBiosynthesis10aMorganella sp.10aNanoparticles10asil gene homologues10aSilver1 aParikh, Rasesh, Y.1 aSingh, Sanjay1 aPrasad, Bhagavatula L. V.1 aPatole, Milind, S.1 aSastry, Murali1 aShouche, Yogesh, S.  uhttps://library.ncl.res.in/content/extracellular-synthesis-crystalline-silver-nanoparticles-and-molecular-evidence-silver-001819nas a2200253   4500008004100000245009700041210006900138260000800207300001000215490000600225520098700231653001701218653001701235653001801252653001701270653001901287100001801306700002501324700002101349700001901370700001701389700003001406856012901436       2010                        eng d00aBacterial synthesis of phtocatalytically active and biocompatible TiO2 and ZnO nanoparticles0 aBacterial synthesis of phtocatalytically active and biocompatibl  cDEC  a80-990 v23 a<p>TiO2 and ZnO nanoparticles are well known for their photocatalytic and ultraviolet (UV)-absorbent properties and have successfully entered into the market as consumer products. Large volume production of these nanoparticles by industries require environmentally friendly processes of synthesis. In this article, we show that when challenged with an appropriate precursor, the bacterium Actinobacter spp. can lead to the extracellular synthesis of ZnO and TiO2 nanoparticles. The biological way of synthesizing these materials probably leads to the in situ doping of elements like C, F, and N into their crystal lattices, which is evidenced by a red shift in the absorption edge. Because the doping is expected to affect the photocatalytic activity of these materials under different light conditions, such investigations have also been undertaken here. Further, the biocompatibility of these nanomaterials (cytotoxicity and genotoxicity) has also been investigated in detail.</p>10aBiosynthesis10agenotoxicity10aNanoparticles10aNanotoxicity10aPhotocatalysis1 aSingh, Sanjay1 aBritto, Virginia, D.1 aBharde, Atul, A.1 aSastry, Murali1 aDhawan, Alok1 aPrasad, Bhagavatula L. V.  uhttps://library.ncl.res.in/content/bacterial-synthesis-phtocatalytically-active-and-biocompatible-tio2-and-zno-nanoparticles02140nas a2200253   4500008004100000022001400041245010600055210006900161260009500230300001200325490000700337520118100344653002901525653001701554653002901571653001801600653002201618100002401640700001901664700002701683700001801710700003001728856012801758       2010                        eng d  a1533-488000aVice to virtue: intracellular biogenic nanoparticles for the generation of carbon supported catalysts0 aVice to virtue intracellular biogenic nanoparticles for the gene  a25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USAbAMER SCIENTIFIC PUBLISHERScFEB  a905-9110 v103 a<p>Intracellular biogenic nanoparticles are considered disadvantageous as the separation of the nanoparticles from the biomass becomes intricate. However realizing the importance of carbon supported catalyst for many important organic reactions we envisaged these nanoparticles as a source for carbon supported catalyst. Herein we demonstrate the heat treatment of intracellular biogenic nanoparticles under inert atmosphere as an efficient method for the preparation of carbon supported metal oxide catalysts. Aspergillus ochraceus, a fungus isolated from foundries, on incubation with K(2)TiF(6) led to the synthesis of intracellular titanium oxide nanoparticles. The nanoparticles embedded biomass upon heat treatment at 600 degrees C in a nitrogen environment gave titanium oxide nanoparticles implanted in a carbonaceous matrix. The material thus formed was characterized using FTIR spectroscopy, Raman spectroscopy, HRTEM and X-ray diffraction. Appreciable benzaldehyde selectivity was observed when styrene oxidation was carried out over such immobilized catalysts. The conversion rate was determined to be 76% and the benzaldehyde selectivity was greater than 80%.</p>10aBenzaldehyde Selectivity10aBiosynthesis10aCarbon Supported Titania10aNanoparticles10aStyrene Oxidation1 aVijayakumar, P., S.1 aSelvakumar, S.1 aGholap, Ramkrishna, S.1 aSingh, A., P.1 aPrasad, Bhagavatula L. V.  uhttps://library.ncl.res.in/content/vice-virtue-intracellular-biogenic-nanoparticles-generation-carbon-supported-catalysts-0