Journal of Microbiology and Biotechnology, May 1, 2012
With an aim to isolate a tannase positive organism, the microbial mat growing on the stored areca... more With an aim to isolate a tannase positive organism, the microbial mat growing on the stored areca extract leachate surface was screened. Once the tannase positive organism was isolated, it was identified by ITS/18S rRNA gene sequencing. Further, the enzyme was purified and examined for its biochemical properties. A potent extracellular tannase-producing yeast was isolated and was identified as Geotrichum cucujoidarum. After the shake flask studies, the enzyme activity of 4.42 U/ml and specific activity of 29.86 U/mg were achieved in a medium with tannic acid as an inducer. Later, ethanol (70%) precipitation followed by purification through FPLC using SEC 650 column resulted in 166.37 U/mg specific activity and a recovery of 50.54%. The purified enzyme was a monomer with a molecular weight of 63 kDa. The optimum pH and the temperature of the enzyme were found to be 5.0 and 30°C, respectively. The Michaelis-Menten constant (Km) was found to be 2.9 mM, and the turn over number (kcat) and catalytic efficiency (kcat/km) of the purified tannase were 102 S-1 and 35.17 mM-1S-1 respectively. Temperature and pH stability profiles of the enzyme, influence of various metal ions, chelators and surfactants on enzyme activity and kinetic constants of enzyme shows that the tannase produced from Geotrichum cucujoidarum is unique and is a potential candidate for further studies.
Stevia rebaudiana Bertoni (Asteraceae) is one of the most important commercial crops in the world... more Stevia rebaudiana Bertoni (Asteraceae) is one of the most important commercial crops in the world (4). It is known to produce glycosides that are as much as 300 times sweeter than sucrose and do not affect blood sugar levels. Unlike artificial sweeteners like saccharin, they are noncarcinogenic and safe for diabetics. An unknown disease emerged during the summers of 2007 to 2009 in a field of S. rebaudiana at CIMAP Lucknow, India, where more than 20% of the plants exhibited symptoms typical of phytoplasma infection including leaf yellowing, reduced size of leaves, shoot proliferation, flower bud deficiency, as well as bushy and stunted growth. Some of these plants were potted and kept in a glasshouse for investigation. Affected plants in the field expressed a quick decline consisting of growth cessation, bronzing of mature leaves, wilting, and death, resulting in a significant reduction in biomass and quality. Typical phytoplasma-like (pleomorphic) bodies ranging from 450 to 900 nm ...
Journal of Biomolecular Structure and Dynamics, 2015
We have investigated in vitro antifungal efficiency of nitrogen-doped carbon nanohorn (NCNH) agai... more We have investigated in vitro antifungal efficiency of nitrogen-doped carbon nanohorn (NCNH) against Rhizoctonia solani (R. solani) plant pathogenic fungi. NCNH with size of 50-60 nm and concentrations of 10, 50, 100, and 150 μg mL(-1) were used. The results showed that growth of fungi in the presence of NCNH was significantly (p > .05) inhibited at 150 μg mL(-1) (85.13 ± .97) after 72 h. The results were validated through computational approaches. Molecular docking analysis of NCNH with endochitinase protein of R. solani was performed to validate the potential of antifungal activity of NCNH. Docking results showed different conformations of interaction of NCNH with endochitinase enzyme. The conformation with least binding energy -13.54 kcal/mol was considered further. It is likely that NCNH interacts with the pathogens by mechanically wrapping, which may be one of the major toxicity actions of NCNH against R. solani. The analysis showed that NCNH might interwinds to endochitinase of R. solani leading to the deactivation of the enzyme. To best of our knowledge, this is the first report of antifungal efficacy of NCNH against R. solani and provides useful information about the application of NCNH in resisting crop disease.
A new strain, SD12, was isolated from tannery waste polluted soil and identified as Pseudomonas a... more A new strain, SD12, was isolated from tannery waste polluted soil and identified as Pseudomonas aeruginosa on the basis of phenotypic traits and by comparison of 16S rRNA sequences. This bacterium exhibited broad-spectrum antagonistic activity against phytopathogenic fungi. The strain produced phosphatases, cellulases, proteases, pectinases, and HCN and also retained its ability to produce hydroxamate-type siderophore. A bioactive metabolite was isolated from P. aeruginosa SD12 and was characterized as 1-hydroxyphenazine ((1-OH-PHZ) by nuclear magnetic resonance (NMR) spectral analysis. The strain was used as a biocontrol agent against root rot and wilt disease of pyrethrum caused by Rhizoctonia solani. The stain is also reported to increase the growth and biomass of Plantago ovata. The purified compound, 1-hydroxyphenazine, also showed broad-spectrum antagonistic activity towards a range of phytopathogenic fungi, which is the first report of its kind.
A bacterial strain, Streptomyces sp. CIMAP- A1 was isolated from Geranium rhizosphere and identif... more A bacterial strain, Streptomyces sp. CIMAP- A1 was isolated from Geranium rhizosphere and identified by morphological, physiological, biochemical and molecular characters (16S rDNA gene sequence). Phylogenetically, it was found most closely related to S. vinacendrappus, strain NRRL-2363 with 99% sequence similarity. The strain had potential antagonistic activity (in vitro) against wide range of phytopathogenic fungi like Stemphylium sp., Botrytis cinerea, Sclerotinia sclerotiorum, Colletotrichum spp., Curvularia spp., Corynespora cassicola and Thielavia basicola. The extracellular secondary metabolites produced by the strain in the culture filtrates significantly inhibited the spore germination, growth of germ tube of the germinated spores and radial growth of Alternaria alternata, Colletotrichum acutatum, Curvularia andropogonis and Fusarium moniliforme. The extraction of culture filtrate with solvents and purification by following VLC and PTLC methods always yielded a 10th fractio...
Bacterial strains PsF84 and PsF610 were isolated from tannery sludge polluted soil, Jajmau, Kanpu... more Bacterial strains PsF84 and PsF610 were isolated from tannery sludge polluted soil, Jajmau, Kanpur, India. 16S rRNA gene sequence and phylogenetic analysis confirmed the taxonomic affiliation of PsF84 as Pseudomonas monteilii and PsF610 as Pseudomonas plecoglossicida. A greenhouse study was carried out with rose-scented geranium (Pelargonium graveolenscv. bourbon) grown in soil treated with tannery sludge in different proportions viz. soil: sludge ratio of 100:0, 25:75, 50:50, 75:25 and 0:100 to evaluate the effects of bacterial inoculation on the heavy metal uptake. The isolates solubilized inorganic phosphorus and were capable of producing indole acetic acid (IAA) and siderophore. The isolate PsF84 increased the dry biomass of shoot by 44%, root by 48%, essential oil yield 43% and chlorophyll by 31% respectively over uninoculated control. The corresponding increase with the isolate PsF610 were 38%, 40%, 39% and 28%, respectively. Scanning electron microscopic (SEM) studies reveal ...
Four different arbuscular mycorrhizal (AM) fungi, Glomus aggregatum, Glomus fasciculatum, Glomus ... more Four different arbuscular mycorrhizal (AM) fungi, Glomus aggregatum, Glomus fasciculatum, Glomus intraradices and Glomus mosseae, were used alone and in combinations with Bacillus subtilis to evaluate their capability to increase the productivity of geranium. Mycorrhizal treatment increased the growth and total biomass invariably over non-mycorrhizal control plants. In AM alone treatment, the best result was obtained for G. mosseae treatment, where 380.9 and 335.3 g fresh herb yield per pot was recorded in ...
Abstract: A new strain of Streptomyces was isolated from heavy metal polluted soil of industrial ... more Abstract: A new strain of Streptomyces was isolated from heavy metal polluted soil of industrial (tannery) area of Jajmau, Kanpur, India. The strain was designated as Streptomyces sp. CIMAP A 2 based on cultural, morphological and physiological studies. Further, molecular characterization of the strain was carried out based on sequencing 1520 bp fragment of 16s rRNA amplicon, which validated it as Streptomyces species (MTCC 10489). The strain was found to be antagonistic to different human pathogenic bacteria as ...
Journal of Microbiology and Biotechnology, May 1, 2012
With an aim to isolate a tannase positive organism, the microbial mat growing on the stored areca... more With an aim to isolate a tannase positive organism, the microbial mat growing on the stored areca extract leachate surface was screened. Once the tannase positive organism was isolated, it was identified by ITS/18S rRNA gene sequencing. Further, the enzyme was purified and examined for its biochemical properties. A potent extracellular tannase-producing yeast was isolated and was identified as Geotrichum cucujoidarum. After the shake flask studies, the enzyme activity of 4.42 U/ml and specific activity of 29.86 U/mg were achieved in a medium with tannic acid as an inducer. Later, ethanol (70%) precipitation followed by purification through FPLC using SEC 650 column resulted in 166.37 U/mg specific activity and a recovery of 50.54%. The purified enzyme was a monomer with a molecular weight of 63 kDa. The optimum pH and the temperature of the enzyme were found to be 5.0 and 30°C, respectively. The Michaelis-Menten constant (Km) was found to be 2.9 mM, and the turn over number (kcat) and catalytic efficiency (kcat/km) of the purified tannase were 102 S-1 and 35.17 mM-1S-1 respectively. Temperature and pH stability profiles of the enzyme, influence of various metal ions, chelators and surfactants on enzyme activity and kinetic constants of enzyme shows that the tannase produced from Geotrichum cucujoidarum is unique and is a potential candidate for further studies.
Stevia rebaudiana Bertoni (Asteraceae) is one of the most important commercial crops in the world... more Stevia rebaudiana Bertoni (Asteraceae) is one of the most important commercial crops in the world (4). It is known to produce glycosides that are as much as 300 times sweeter than sucrose and do not affect blood sugar levels. Unlike artificial sweeteners like saccharin, they are noncarcinogenic and safe for diabetics. An unknown disease emerged during the summers of 2007 to 2009 in a field of S. rebaudiana at CIMAP Lucknow, India, where more than 20% of the plants exhibited symptoms typical of phytoplasma infection including leaf yellowing, reduced size of leaves, shoot proliferation, flower bud deficiency, as well as bushy and stunted growth. Some of these plants were potted and kept in a glasshouse for investigation. Affected plants in the field expressed a quick decline consisting of growth cessation, bronzing of mature leaves, wilting, and death, resulting in a significant reduction in biomass and quality. Typical phytoplasma-like (pleomorphic) bodies ranging from 450 to 900 nm ...
Journal of Biomolecular Structure and Dynamics, 2015
We have investigated in vitro antifungal efficiency of nitrogen-doped carbon nanohorn (NCNH) agai... more We have investigated in vitro antifungal efficiency of nitrogen-doped carbon nanohorn (NCNH) against Rhizoctonia solani (R. solani) plant pathogenic fungi. NCNH with size of 50-60 nm and concentrations of 10, 50, 100, and 150 μg mL(-1) were used. The results showed that growth of fungi in the presence of NCNH was significantly (p > .05) inhibited at 150 μg mL(-1) (85.13 ± .97) after 72 h. The results were validated through computational approaches. Molecular docking analysis of NCNH with endochitinase protein of R. solani was performed to validate the potential of antifungal activity of NCNH. Docking results showed different conformations of interaction of NCNH with endochitinase enzyme. The conformation with least binding energy -13.54 kcal/mol was considered further. It is likely that NCNH interacts with the pathogens by mechanically wrapping, which may be one of the major toxicity actions of NCNH against R. solani. The analysis showed that NCNH might interwinds to endochitinase of R. solani leading to the deactivation of the enzyme. To best of our knowledge, this is the first report of antifungal efficacy of NCNH against R. solani and provides useful information about the application of NCNH in resisting crop disease.
A new strain, SD12, was isolated from tannery waste polluted soil and identified as Pseudomonas a... more A new strain, SD12, was isolated from tannery waste polluted soil and identified as Pseudomonas aeruginosa on the basis of phenotypic traits and by comparison of 16S rRNA sequences. This bacterium exhibited broad-spectrum antagonistic activity against phytopathogenic fungi. The strain produced phosphatases, cellulases, proteases, pectinases, and HCN and also retained its ability to produce hydroxamate-type siderophore. A bioactive metabolite was isolated from P. aeruginosa SD12 and was characterized as 1-hydroxyphenazine ((1-OH-PHZ) by nuclear magnetic resonance (NMR) spectral analysis. The strain was used as a biocontrol agent against root rot and wilt disease of pyrethrum caused by Rhizoctonia solani. The stain is also reported to increase the growth and biomass of Plantago ovata. The purified compound, 1-hydroxyphenazine, also showed broad-spectrum antagonistic activity towards a range of phytopathogenic fungi, which is the first report of its kind.
A bacterial strain, Streptomyces sp. CIMAP- A1 was isolated from Geranium rhizosphere and identif... more A bacterial strain, Streptomyces sp. CIMAP- A1 was isolated from Geranium rhizosphere and identified by morphological, physiological, biochemical and molecular characters (16S rDNA gene sequence). Phylogenetically, it was found most closely related to S. vinacendrappus, strain NRRL-2363 with 99% sequence similarity. The strain had potential antagonistic activity (in vitro) against wide range of phytopathogenic fungi like Stemphylium sp., Botrytis cinerea, Sclerotinia sclerotiorum, Colletotrichum spp., Curvularia spp., Corynespora cassicola and Thielavia basicola. The extracellular secondary metabolites produced by the strain in the culture filtrates significantly inhibited the spore germination, growth of germ tube of the germinated spores and radial growth of Alternaria alternata, Colletotrichum acutatum, Curvularia andropogonis and Fusarium moniliforme. The extraction of culture filtrate with solvents and purification by following VLC and PTLC methods always yielded a 10th fractio...
Bacterial strains PsF84 and PsF610 were isolated from tannery sludge polluted soil, Jajmau, Kanpu... more Bacterial strains PsF84 and PsF610 were isolated from tannery sludge polluted soil, Jajmau, Kanpur, India. 16S rRNA gene sequence and phylogenetic analysis confirmed the taxonomic affiliation of PsF84 as Pseudomonas monteilii and PsF610 as Pseudomonas plecoglossicida. A greenhouse study was carried out with rose-scented geranium (Pelargonium graveolenscv. bourbon) grown in soil treated with tannery sludge in different proportions viz. soil: sludge ratio of 100:0, 25:75, 50:50, 75:25 and 0:100 to evaluate the effects of bacterial inoculation on the heavy metal uptake. The isolates solubilized inorganic phosphorus and were capable of producing indole acetic acid (IAA) and siderophore. The isolate PsF84 increased the dry biomass of shoot by 44%, root by 48%, essential oil yield 43% and chlorophyll by 31% respectively over uninoculated control. The corresponding increase with the isolate PsF610 were 38%, 40%, 39% and 28%, respectively. Scanning electron microscopic (SEM) studies reveal ...
Four different arbuscular mycorrhizal (AM) fungi, Glomus aggregatum, Glomus fasciculatum, Glomus ... more Four different arbuscular mycorrhizal (AM) fungi, Glomus aggregatum, Glomus fasciculatum, Glomus intraradices and Glomus mosseae, were used alone and in combinations with Bacillus subtilis to evaluate their capability to increase the productivity of geranium. Mycorrhizal treatment increased the growth and total biomass invariably over non-mycorrhizal control plants. In AM alone treatment, the best result was obtained for G. mosseae treatment, where 380.9 and 335.3 g fresh herb yield per pot was recorded in ...
Abstract: A new strain of Streptomyces was isolated from heavy metal polluted soil of industrial ... more Abstract: A new strain of Streptomyces was isolated from heavy metal polluted soil of industrial (tannery) area of Jajmau, Kanpur, India. The strain was designated as Streptomyces sp. CIMAP A 2 based on cultural, morphological and physiological studies. Further, molecular characterization of the strain was carried out based on sequencing 1520 bp fragment of 16s rRNA amplicon, which validated it as Streptomyces species (MTCC 10489). The strain was found to be antagonistic to different human pathogenic bacteria as ...
Uploads
Papers by Seema Dharni