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ABSTRACT: Extracellular biogenic synthesis of silver nanoparticles with various shapes using rice bacterial blight bacterium, Xanthomonas oryzae pv. oryzae BXO8 is reported. The synthesized silver nanoparticles are characterized by UV-Vis spectroscopy, powder X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), and high-resolution transmission electron microscopy (HR-TEM). Based on the evidence of HR-TEM, the synthesized particles were found to be spherical with anisotropic structures such as triangles and rods with an average size of 14.86 nm. The crystalline nature of silver nanoparticles is evident from the bright circular spots in the SAED pattern, clear lattice fringes in high resolution TEM images and peaks in the XRD pattern. FTIR spectrum shows biomolecules containing amide and carboxylate groups are involved in the reduction and stabilization of silver nanoparticles. Using such a biological method for the synthesis of silver nanoparticles is a simple, viable, cost-effective, and environment friendly process, which can be used in antimicrobial therapy.
Journal of Microbiology and Biotechnology 06/2013; · 1.38 Impact Factor
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ABSTRACT: The size and morphology determines the thermodynamic, physical and electronic properties of metal nanoparticles. The extracellular synthesis of gold nanoparticles by fungus, Cylindrocladium floridanum, which acts as a source of reducing and stabilizing agent has been described. The synthesized nanoparticles were characterized using techniques such as UV-Vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray analysis (EDAX), and high-resolution transmission electron microscopy (HR-TEM). Based on the evidence of HR-TEM, the synthesized particles were found to be spherical with an average size of 19.05 nm. Powder XRD pattern proved the formation of (111)-oriented face-centered cubic crystals of metallic gold. This microbial approach by fungus for the green synthesis of spherical gold nanoparticles has many advantages such as economic viability, scaling up and environment friendliness.
MIRCEN Journal of Applied Microbiology and Biotechnology 06/2013; · 1.08 Impact Factor
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ABSTRACT: Tobacco wastes that contain nicotine alkaloids are harmful to human health and the environment. In the investigation, a novel nicotine-biodegrading bacterium TND35 was isolated and identified as Pseudomonas plecoglossicida on the basis of phenotypic, biochemical characteristics and 16S rRNA sequence homology. We have studied the nicotine biodegradation potential of strain TND35 by detecting the intermediate metabolites using an array of approaches such as HPLC, GC-MS, NMR and FT-IR. Biotransformation metabolites, N-methylmyosmine, 4-hydroxy-1-(3-pyridyl)-1-butanone (HPB) and other three new intermediate metabolites namely, 3,5-bis (1-methylpyrrolidin-2-yl) pyridine, 2,3-dihydro-1-methyl-5-(pyridin-3-yl)-1H-pyrrol-2-ol and 5-(pyridin-3-yl)-1H-pyrrol-2(3H)-one have been identified. Interestingly, these intermediate metabolites suggest that the strain TND35 employs a novel nicotine biodegradation pathway, which is different from the reported pathways of Aspergillus oryzae 112822, Arthrobacter nicotinovorans pAO1, Agrobacterium tumefaciens S33 and other species of Pseudomonas. The metabolite, HPB reported in this study can also be used as biochemical marker for tobacco related cancer studies.
Biodegradation 04/2013; · 2.02 Impact Factor
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ABSTRACT: β-1,3-Glucanases are abundant in plants and have been characterized from a wide range of species. They play key roles in cell division, trafficking of materials through plasmodesmata, in withstanding abiotic stresses and are involved in flower formation through to seed maturation. They also defend plants against fungal pathogens either alone or in association with chitinases and other antifungal proteins. They are grouped in the PR-2 family of pathogenesis-related (PR) proteins. Use of β-1,3-glucanase genes as transgenes in combination with other antifungal genes is a plausible strategy to develop durable resistance in crop plants against fungal pathogens. These genes, sourced from alfalfa, barley, soybean, tobacco, and wheat have been co-expressed along with other antifungal proteins, such as chitinases, peroxidases, thaumatin-like proteins and α-1-purothionin, in various crop plants with promising results that are discussed in this review.
Biotechnology Letters 08/2012; 34(11):1983-90. · 1.68 Impact Factor
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ABSTRACT: Of 80 fluorescent pseudomonad strains screened for phosphate solubilization, three strains (BFPB9, FP12 and FP13) showed the
ability to solubilize tri-calcium phosphate (Ca3(PO4)2). During mineral phosphate solubilization, decrease of pH in the culture medium due to the production of organic acids by
the strains was observed. These phosphate solubilizing strains produced indole-3-acetic acid (IAA) and protease as well as
exhibited a broad-spectrum antifungal activity against phytopathogenic fungi. When tested in PCR using the gene-specific primers,
strain BFPB9 showed the presence of hcnBC genes that encode hydrogen cyanide. On the basis of phenotypic traits, 16S rRNA sequence homology and subsequent phylogenetic
analysis, strains BFPB9, FP12 and FP13 were designated as Pseudomonas aeruginosa, P. plecoglossicida and P. mosselii, respectively. Present investigation reports the phosphate solubilization potential and biocontrol ability of new strains
that belong to P. plecoglossicida and P. mosselii. Because of the innate potential of phosphate solubilization, production of siderophore, IAA, protease, cellulase and HCN
strains reported in this study can be used as biofertilizers as well as biocontrol agents.
World Journal of Microbiology and Biotechnology 04/2012; 25(4):573-581. · 1.53 Impact Factor
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ABSTRACT: Fluorescent pseudomonads from banana rhizospheric soil were isolated and screened for the production of enzymes and hormones
such as phosphatase, indole-3-acetic acid (IAA), 1-aminocyclopropane-1-carboxylate (ACC) deaminase, protease, and antifungal
metabolites. Of 95 isolates, 50 (52%) isolates solubilized tri-calcium phosphate (TCP), 63 (66%) isolates produced plant growth
hormone IAA, 10 (11%) isolates exhibited ACC deaminase, and 23 (24%) isolates produced protease. Isolates were screened for
antifungal activity toward phytopathogenic fungi. Gene-specific primers have identified the putative antibiotic producing
isolates. These putative isolates were grown in the production media and production of antibiotics was confirmed by thin-layer
chromatography (TLC) and high-performance liquid chromatography (HPLC). Genotypic analysis by BOX (bacterial repetitive BOX
element)-polymerase chain reaction (PCR) resulted into three distinct genomic clusters at a 50% similarity level and 62 distinct
BOX profiles. Based on the sequence similarity of 16S rRNA and construction of subsequent phylogenetic tree analysis, isolates
were designated as Pseudomonas monteilii, P. plecoglossicida, P. fluorescens, P. fulva, P. mosselii, P. aeruginosa, P. alcaligenes, and P. pseudoalcaligenes. Present study revealed the genetic and functional diversity among isolates of fluorescent pseudomonads associated with rhizospheric
soil of banana and also identified P. monteilii as dominant species. The knowledge on genetic and functional diversity of fluorescent pseudomonads associated with banana
rhizosphere is useful to understand their ecological role and for their utilization in sustainable agriculture.
Microbial Ecology 04/2012; 56(3):492-504. · 2.91 Impact Factor
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ABSTRACT: The size, shape and controlled dispersity of nanoparticles play a vital role in determining the physical, chemical, optical and electronic properties attributing its applications in environmental, biotechnological and biomedical fields. Various physical and chemical processes have been exploited in the synthesis of several inorganic metal nanoparticles by wet and dry approaches viz., ultraviolet irradiation, aerosol technologies, lithography, laser ablation, ultrasonic fields, and photochemical reduction techniques. However, these methodologies remain expensive and involve the use of hazardous chemicals. Therefore, there is a growing concern for the development of alternative environment friendly and sustainable methods. Increasing awareness towards green chemistry and biological processes has led to a necessity to develop simple, cost-effective and eco-friendly procedures. Phototrophic eukaryotes such as plants, algae, and diatoms and heterotrophic human cell lines and some biocompatible agents have been reported to synthesize greener nanoparticles like cobalt, copper, silver, gold, bimetallic alloys, silica, palladium, platinum, iridium, magnetite and quantum dots. Owing to the diversity and sustainability, the use of phototrophic and heterotrophic eukaryotes and biocompatible agents for the synthesis of nanomaterials is yet to be fully explored. This review describes the recent advancements in the green synthesis and applications of metal nanoparticles by plants, aquatic autotrophs, human cell lines, biocompatible agents and biomolecules.
Advances in colloid and interface science 12/2011; 169(2):59-79. · 5.68 Impact Factor
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ABSTRACT: In the present investigation, the silver-bionanocomposite with fcc structured Ag-nanocrystals was synthesized using the fungus, Cylindrocladium floridanum through a novel, environmentally benign biological process. Silver-bionanocomposite was systematically characterized by UV-Vis spectroscopy, XRD, SEM, EDX, and TEM techniques. TEM analysis of mycelia confirmed the presence of silver nanoparticles (AgNPs) on the outer surface of the cell wall and inner of cytoplasmic membrane of the fungus, when cultured in aqueous solution of AgNO3 at 30 °C for a period of 7 days in static condition. Additionally, it was observed that bionanocomposite with AgNPs functions as an efficient heterogeneous catalyst in the degradation of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP), in the presence of reducing agent, sodium borohydride which was reflected by UV-Vis spectra of the catalytic reaction kinetics. This is the first report of the silver-bionanocomposite using fungus, Cy. floridanum, heterogeneously catalyzing the reduction of a toxic pollutant, 4-NP to 4-AP.
Bioresource technology 08/2011; 102(22):10737-40. · 4.25 Impact Factor
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ABSTRACT: Greener synthesis of nanogold-biocomposite by fungus, Cylindrocladium floridanum was reported in this study. Results revealed that when cultured in static condition for a period of 7d, the fungus accumulated gold nanoparticles on the surface of the mycelia. Bionanocomposites with Au nanocrystals were characterized by UV-Vis spectroscopy, XRD, SEM, EDX and high-resolution TEM. The SPR band of UV-Vis spectrum at 540 nm confirmed the presence of gold nanoparticles on the surface of the fungal mycelia. The fcc (111)-oriented crystalline nature of particles was identified by XRD pattern. The synthesized particles are spherical in shape as evidenced by TEM image. The biocomposites with Au nanoparticles function as an efficient heterogeneous catalyst in the degradation of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP), in the presence of reducing agent, sodium borohydride which was reflected by UV-Vis spectra of the catalytic reaction kinetics. The reduction of 4-nitrophenol follows pseudo-first-order kinetic model with the reaction rate constant of 2.67 × 10(-2)min(-1) with 5.07 × 10(-6)mol/dm(3) of gold at ca. 25 nm. The rate of the reaction was increased by increasing the concentration of gold nanoparticles from 2.54 × 10(-6) to 12.67 × 10(-6)mol/dm(3) (∼ 25 nm) and with reduced size from 53.2 to 18.9 nm respectively. This is the first report on fungal-matrixed gold(0) nanocomposites heterogeneously catalyzing the reduction of the toxic organic pollutant, 4-nitrophenol that enable the recovery and recycling of AuNPs catalysts.
Journal of hazardous materials 02/2011; 189(1-2):519-25. · 4.14 Impact Factor
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ABSTRACT: Antagonistic fluorescent pseudomonads isolated from rice rhizospheric soil were characterized using biochemical, taxonomical and molecular tools. Production of cyclopropane fatty acid (CFA) was correlated with their antagonistic potential. Strains were grouped into 18 different genotypes on the basis of amplified ribosomal DNA restriction analysis (ARDRA) and repetitive (rep)-PCR based genotypic fingerprinting analyses. High phylogenetic resolution among antagonistic fluorescent pseudomonad strains was obtained based on the DNA gyrase B subunit (gyrB) and RNA polymerase sigma factor 70 (rpoD) gene sequence analyses. Combined gyrB and rpoD sequence analysis resulted in the accurate estimation of molecular phylogeny and provided a significant correlation between the genetic distances among strains. Present study demonstrated the genetic and functional relationship of fluorescent pseudomonads. The knowledge on genetic and functional potential of fluorescent pseudomonads associated with rice rhizosphere is useful to understand their ecological role and for their utilization in sustainable agriculture.
The Journal of Microbiology 12/2010; 48(6):715-27. · 1.10 Impact Factor
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ABSTRACT: An array of physical, chemical and biological methods have been used to synthesize nanomaterials. In order to synthesize noble metal nanoparticles of particular shape and size specific methodologies have been formulated. Although ultraviolet irradiation, aerosol technologies, lithography, laser ablation, ultrasonic fields, and photochemical reduction techniques have been used successfully to produce nanoparticles, they remain expensive and involve the use of hazardous chemicals. Therefore, there is a growing concern to develop environment-friendly and sustainable methods. Since the synthesis of nanoparticles of different compositions, sizes, shapes and controlled dispersity is an important aspect of nanotechnology new cost-effective procedures are being developed. Microbial synthesis of nanoparticles is a green chemistry approach that interconnects nanotechnology and microbial biotechnology. Biosynthesis of gold, silver, gold-silver alloy, selenium, tellurium, platinum, palladium, silica, titania, zirconia, quantum dots, magnetite and uraninite nanoparticles by bacteria, actinomycetes, fungi, yeasts and viruses have been reported. However, despite the stability, biological nanoparticles are not monodispersed and the rate of synthesis is slow. To overcome these problems, several factors such as microbial cultivation methods and the extraction techniques have to be optimized and the combinatorial approach such as photobiological methods may be used. Cellular, biochemical and molecular mechanisms that mediate the synthesis of biological nanoparticles should be studied in detail to increase the rate of synthesis and improve properties of nanoparticles. Owing to the rich biodiversity of microbes, their potential as biological materials for nanoparticle synthesis is yet to be fully explored. In this review, we present the current status of microbial synthesis and applications of metal nanoparticles.
Advances in colloid and interface science 02/2010; 156(1-2):1-13. · 5.68 Impact Factor
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ABSTRACT: Phosphorus is an essential macronutrient for the growth of plants. However, in most soils a large portion of phosphorus becomes insoluble and therefore, unavailable to plants. Knowledge on biodiversity of phosphate-solubilizing fluorescent pseudomonads is essential to understand their ecological role and their utilization in sustainable agriculture.
Of 443 fluorescent pseudomonad strains tested, 80 strains (18%) showed positive for the solubilization of tri-calcium phosphate (Ca3(PO4)2) by the formation of visible dissolution halos on Pikovskaya's agar. These phosphate solubilizing strains showed high variability in utilizing various carbon sources. Numerical taxonomy of the phosphate solubilizing strains based on their carbon source utilization profiles resulted into three major phenons at a 0.76 similarity coefficient level. Genotypic analyses of strains by BOX (bacterial repetitive BOX element)-polymerase chain reaction (PCR) resulted into three distinct genomic clusters and 26 distinct BOX profiles at a 80% similarity level. On the basis of phenotypic characterization and 16S rRNA gene phylogenetic analyses strains were identified as Pseudomonas aeruginosa, P. mosselii, P. monteilii, P. plecoglossicida, P. putida, P. fulva and P. fluorescens. These phosphate solubilizing strains also showed the production of plant growth promoting enzymes, hormones and exhibited antagonism against phytopathogenic fungi that attack on various crops. Gene specific primers have identified the putative antibiotic producing strains. These putative strains were grown in fermentation media and production of antibiotics was confirmed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC).
Present study revealed a high degree of functional and genetic diversity among the phosphate solubilizing fluorescent pseudomonad bacteria. Due to their innate potential of producing an array of plant growth promoting enzymes, hormones and antifungal metabolites these phosphate solubilizing strains are considered to play a vital role in plant growth promotion, disease suppression and subsequent enhancement of yield.
BMC Microbiology 01/2009; 8:230. · 3.04 Impact Factor
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ABSTRACT: Plant transformation systems for creating transgenics require separate process for introducing cloned DNA into living plant cells. Identification or selection of those cells that have integrated DNA into appropriate plant genome is a vital step to regenerate fully developed plants from the transformed cells. Selectable marker genes are pivotal for the development of plant transformation technologies because marker genes allow researchers to identify or isolate the cells that are expressing the cloned DNA, to monitor and select the transformed progeny. As only a very small portion of cells are transformed in most experiments, the chances of recovering transgenic lines without selection are usually low. Since the selectable marker gene is expected to function in a range of cell types it is usually constructed as a chimeric gene using regulatory sequences that ensure constitutive expression throughout the plant. Advent of recombinant DNA technology and progress in plant molecular biology had led to a desire to introduce several genes into single transgenic plant line, necessitating the development of various types of selectable markers. This review article describes the developments made in the recent past on plant transformation systems using different selection methods adding a note on their importance as marker genes in transgenic crop plants.
Journal of plant physiology 10/2008; 165(16):1698-716. · 2.50 Impact Factor
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ABSTRACT: Site-directed mutagenesis on a recombinant plasmid, pUC8, that contained the cah gene, was conducted and confirmed by sequence analysis. Single base substitution, G to A at nucleotide position 81 or T to C at nucleotide position 84 of cah gene does not change the amino acid sequence of cah enzyme but eliminates the HindIII site. The wild-type cah and its mutants were cloned and overexpressed in pQE-60 Escherichia coli expression system. Western blot analysis confirmed the production of 27.7-kDa cah enzyme by all the recombinants. The mutated cah gene devoid of HindIII site was used to generate a recombinant plant transformation vector (pCAMBIA-cah). Agrobacterium-mediated transformation was performed in Nicotiana tabaccum cv. Samsun plants by employing the leaf-disc method. The integration and expression of cah gene in transgenic plants were confirmed by polymerase chain reaction, Southern and Western blot analyses. Antimicrobial activity of cyanamide against phytopathogenic fungi and bacteria was determined. Cyanamide can be used as fertilizer as well as an antimicrobial salt against phytopathogenic fungi and bacteria. The present investigation reports the heterologous expression of the cah marker gene. Due to its innate ability to convert cyanamide to urea and the broad-spectrum antimicrobial activity of cyanamide, the cah gene can be used to facilitate plant growth promotion and biocontrol of phytopathogens.
Current Microbiology 02/2008; 56(1):42-7. · 1.82 Impact Factor
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ABSTRACT: Abstract
Background
Phosphorus is an essential macronutrient for the growth of plants. However, in most soils a large portion of phosphorus becomes insoluble and therefore, unavailable to plants. Knowledge on biodiversity of phosphate-solubilizing fluorescent pseudomonads is essential to understand their ecological role and their utilization in sustainable agriculture.
Results
Of 443 fluorescent pseudomonad strains tested, 80 strains (18%) showed positive for the solubilization of tri-calcium phosphate (Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>) by the formation of visible dissolution halos on Pikovskaya's agar. These phosphate solubilizing strains showed high variability in utilizing various carbon sources. Numerical taxonomy of the phosphate solubilizing strains based on their carbon source utilization profiles resulted into three major phenons at a 0.76 similarity coefficient level. Genotypic analyses of strains by BOX (bacterial repetitive BOX element)-polymerase chain reaction (PCR) resulted into three distinct genomic clusters and 26 distinct BOX profiles at a 80% similarity level. On the basis of phenotypic characterization and 16S rRNA gene phylogenetic analyses strains were identified as Pseudomonas aeruginosa, P. mosselii, P. monteilii, P. plecoglossicida, P. putida, P. fulva and P. fluorescens . These phosphate solubilizing strains also showed the production of plant growth promoting enzymes, hormones and exhibited antagonism against phytopathogenic fungi that attack on various crops. Gene specific primers have identified the putative antibiotic producing strains. These putative strains were grown in fermentation media and production of antibiotics was confirmed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC).
Conclusion
Present study revealed a high degree of functional and genetic diversity among the phosphate solubilizing fluorescent pseudomonad bacteria. Due to their innate potential of producing an array of plant growth promoting enzymes, hormones and antifungal metabolites these phosphate solubilizing strains are considered to play a vital role in plant growth promotion, disease suppression and subsequent enhancement of yield.
BMC Microbiology. 01/2008;
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ABSTRACT: Sheath rot disease of rice caused by Sarocladium oryzae (Sawada) (=Acrocylindrium oryzae, Sawada) has become an important production constraint in all rice-growing countries. Pathogenicity, phytotoxic metabolites, and random amplified polymorphic DNA (RAPD) markers were used to assess the level of genetic variability of S. oryzae derived from rice cultivars, CR1018, IR36, and IR50, of different locations in North East and South India. Variability in pathogenicity, phytotoxic metabolite production, and DNA polymorphisms was detected among S. oryzae isolates. Results indicated that S. oryzae isolates produced both cerulenin and helvolic acid at concentrations 0.3-0.62 and 0.9-4.8 microg mL(-1) of culture filtrate, respectively. Isolates that produce higher concentration of helvolic acid induced a high percent incidence of sheath rot disease. Oligonucleotide primers, GF and MR, generated either a simple (up to 2 bands) or complex (up to 6 bands) RAPD pattern. According to their level of similarity, S. oryzae isolates from North East and South India were grouped separately into two major clusters and 13 genotypes. Molecular- and pathogenicity-based classifications were not correlated, but a high level of genetic variability within S. oryzae isolates was identified. The molecular variability of S. oryzae isolates will be an important consideration in breeding programs to develop durable resistance for sheath rot disease.
Current Microbiology 07/2005; 50(6):319-23. · 1.82 Impact Factor
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ABSTRACT: In order to understand the mode of action of taxonomically related Pseudomonas syringae pathovar strains that infect pea, tomato, and soya bean, we examined their extracellular polysaccharides (EPS). Maximum production of polysaccharide in shake culture of these pathogens was observed between 24 and 60 h. P. syringae pv. pisi 519, the bacterial blight pathogen of pea, produced a higher amount of polysaccharide (34.87 microg/mL) at 60 h compared with 32.67 microg/mL produced by P. syringae pv. glycinea NCPPB 1783, the bacterial blight pathogen of soya bean, and 30.03 microg/mL produced by P. syringae pv. tomato NCPPB 269, the bacterial speck pathogen of tomato. EPS produced by P. syringae pv. pisi 519, P. syringae pv. tomato NCPPB 269, and P. syringae pv. glycinea NCPPB 1783 was characterized with infrared (FTIR), nuclear magnetic resonance (NMR), high performance thin layer chromatography, (HPTLC), and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. HPTLC profiles revealed the presence of glucose and glucuronic acid in all bacteria and mannose only in P. syringae pv. tomato. Molecular mass of EPS of P. syringae pv. pisi (m/z 933.8), P. syringae pv. tomato (m/z 950.4), and P. syringae pv. glycinea (m/z 933.5) was confirmed by MALDI-TOF mass spectrometry.
Current Microbiology 08/2004; 49(1):35-41. · 1.82 Impact Factor
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ABSTRACT: A novel hydrocarbonoclastic bacterium was isolated from rice rhizospheric soil using an enrichment culture technique. Detailed taxonomic studies identified the organism, designated strain PUP6, as a member of the genus Pseudomonas. The bacterium grew in minimal medium amended with n-alkane members of hydrocarbons, n-dodecane (C12H26), n-hexadecane (C16H34), n-octadecane (C18H38), n-octacosane (C28H58); and petroleum fractions such as crude oil and lubricating oil when provided as sole carbon and energy source. Degradation of these n-alkane hydrocarbons and oils in minimal salts medium by strain PUP6 was estimated using gas chromatography with a flame ionization detector. In addition to its hydrocarbonoclastic properties, this bacterium exhibits a broad spectrum of fungal antibiosis against various phytopathogenic fungi. An antifungal metabolite produced by strain PUP6 was isolated, characterized and identified as phenazine-1-carboxamide on the basis of nuclear magnetic resonance and mass spectroscopic analyses. Strain PUP6 also produced plant-growth-promoting siderophores, indoleacetic acid (IAA), phosphate solubilizing enzymes, and fungal cell wall degrading enzymes such as protease and chitinase. This study can be considered as the first report on n-alkane hydrocarbon and oil degradation by a rhizosphere soil bacterium that exhibits biofertilizing and biocontrol traits. Due to its innate multiple functional traits beyond its role in degradation of hydrocarbons, strain PUP6 may be used as plant-growth-promoting rhizobacterium and biocontrol agent against phytopathogenic fungi.
Research in Microbiology 157(6):538-46. · 2.76 Impact Factor
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ABSTRACT: In this paper, we report the facile environmental friendly “greener synthesis” of anisotrophic nanostructures and isotrophic spherical gold nanoparticles using the cell-free filtrate of fungus, Sclerotium rolfsii. We found that NADPH-dependent enzyme present in the cell-free filtrate of S. rolfsii, when incubated with the aqueous chloroauric acid solution has the ability to synthesize gold nanoparticles within 10–15 min at ambient temperature. The morphologies of synthesized nanoparticles were anisotrophic like triangles, hexagonals, decahedrals, and rods and isotrophic sphericals. The synthesized isotrophic spherical nanoparticles were in the average size of ca. 25 nm and stable in aqueous solution up to 2 months. The shape and size of gold nanoparticles were modulated by the change in the ratio of metal salt and cell-free filtrate of S. rolfsii. Spherical and anisotrophic shapes like triangles, decahedrals, hexagonals and rods nanoparticles were produced at higher and lower concentrations of filtrate respectively. The controlled synthesis of well-defined size, shape and composition has enormous applications in the fields of biolabeling, biosensing, drug delivery, cancer therapy and catalysis.Graphical abstractHighlights► Synthesis of AuNPs using the cell-free filtrate of Sclerotium rolfsii was described. ► UV–Vis absorption spectra showed facile formation of AuNPs in 10–15 min. ► XRD analysis showed intense peaks corresponding to the fcc structure of AuNPs. ► HR-TEM analysis confirmed the formation of stable anisotrophic and isotrophic AuNPs. ► SDS-PAGE showed NADPH-dependent enzyme may be responsible for the formation of AuNPs.
Colloids and Surfaces A Physicochemical and Engineering Aspects 380:156-161. · 2.24 Impact Factor
