Showing papers in "Indian Journal of Microbiology in 2003"

Phosphate solubilization, exopolysaccharide production and indole acetic acid secretion by rhizobacteria isolated from Trigonella foenum-graecum

Abstract: Nine different bacteria isolated from the rhizosphere of field grown Trigonella were identified as Bacillus, Pseudomonas, Azotobacter, Rhizobium and Azospirillum. They were examined for solubilization of phosphate and production of exopolysaccharide and indole acetic acid. In addition to Pseudomonas isolate (TP2), Rhizobium also showed high tricalcium phosphate solubilizing activity in both solid and liquid medium. Increased incubation time and shake conditions improved the level of phosphate solubilizing activity in Bacillus isolate TB3. Azospirillium produced more exopolysaccharide and its hexose content was also higher in comparison to other isolates. Indole acetic acid production was maximum in Rhizobium after 96 h of incubation. The study supports that Rhizobium can be considered as an important PGPR for legumes as well as non-legumes.

Native microorganisms in the fermentation of kinema

Abstract: Kinema is a naturally fermented indigenous soybean food, common to the eastern himalayan regions of India, Nepal and Bhutan. Microbial diversity in kinema was assessed to establish the source of inocula during spontaneousfermentation. Microorganisms associated with kinema were present in or on the ingredient, equipment, ash and wrapping materials, which also contributed significant genetic resources. Species of Bacillus, Enterococcus, Geotrichum, Candida were recovered.

Production of α-amylase by Aspergillus niger using wheat bran in submerged and solid state fermentations

Abstract: Aspergillus niger NCIM 1248 produced α-amylase during submerged fermentation (SF) and solid state fermentation (SSF) conditions of wheat bran with mineral solution as moistening agent. At pH 5 and temperature 30°C, SSF in5 d and SF in 4 d produced optimum levels of α-amylase (50 and 33.3 Ug - 1 respectively). Supplementation of medium with sodium nitrate (0.2% N, w/w) and soluble starch (10%, w/w) led to maximum α-amylase production of 89.3 and 64.3 U g - 1 in SSF and SF fermentation respectively.

Efficiency of some phosphatase producing soil-fungi

Abstract: Seven efficient phosphatase producing fungi (PPF) were isolated and identified as Aspergillus rugulosus, A. fumigatus, A. terreus, A. niger, A. parasiticus, Pseudeurotium zonatum and Trichoderma harzianum. Their efficiency to hydrolyze different compounds of organic phosphorus (mono- and hexa-) was examined. The fungi reduced the pH of the medium, which was maximum with A. niger. A significant negative correlation of pH with development of fungal mats was observed (r = -0.39, n = 28, p < 0.05). The maximum secretion of acid phosphatase by PPF was at 21 d and alkaline phosphatase at 14 d. Acid phosphatase produced by PPF was three times higher than alkaline phosphatase. The intracellular phosphatase activity was significantly higher than extracellular activity. The efficiency to hydrolyse mono-phosphate by phosphatases released from the PPF was 4-times higher than hexa phosphate. T. harzianum was found to be most efficient organic P mobilizer as compared to the other fungi, tested. The efficiency per unit of enzyme produced by different fungi was different and that indicated the isoenzymes being of different types.

Optimisation of growth conditions for the production of extracellular lipase by Bacillus mycoides

Abstract: A bacterium, producing extracellular lipase was isolated from coconut oil cake and identified as Bacillus mycoides by morphological and biochemical characteristics. Growth of the organism and lipase production was maximumafter 72 h of incubation. It was unable to grow at 50° C. The optimum pH and temperature for the production of lipase were 8 and 28° C. Shake condition induced more lipase production. Olive oil and beef extract were found to be the best carbon and nitrogen sources. Na + induced more lipase than K + and Mg 2 +.

Impact of different carbon and nitrogen sources on phosphate solubilization by Pseudomonas fluorescens

Abstract: Various compounds of carbon and nitrogen were tested for their effect on solubilization of tricalcium phosphate (TCP) and rock phosphate (RP) by Pseudomonas fluorescens. Glucose and galactose were found to be the best carbon source while ammonium sulphate as best nitrogen source. Optimum C:N ratio for the solubilization was found to be 40 and the pH drift was always towards acidic side.

Bioregulatory and therapeutic effects of blue green algae

Abstract: In recent years, there has been a tremendous increase in the interest in micro algal metabolites. A novel 11-kDa virucidal protein, named cyanovirin- N (CV-N) has been isolated and sequenced from cultures of filamentous blue green alga, Nostoc ellipsosporum. This compound irreversibly inactivated diverse T-lymphocyte-tropic (T-tropic), laboratory adapted strains of HIV type 1, HIV type 2 and simian immunodeficiency virus (SIV). A water based extract of Aphanizommon flosaquae containing high concentrations of phycocyanin inhibited the in vitro growth of one out of four tumor cell lines, indicating that at least some tumor cell types may be directly sensitive to killing by phycocyanin. Another fresh water blue-green alga, Phormidium tenue containing several diacyl-glycerol compounds effectively inhibited chemically induced skin tumors in mice. Studies on whole blue green algae in humans, mice, rats, cats and chickens have demonstrated their effect on phagocytosis, NK cell function and inflammation. Blue green algae in general contain a significant amount of carotenoids, namely beta carotene, lycopene and lutein, providing it good antioxidant properties. By their quenching action on reactive oxygen species, antioxidants carry intrinsic anti-inflammatory properties. Macrolides are one of the structural types often seen in Streptomyces-metabolites, and several major antibiotics belong to this class. Macrolides are also produced by blue green algae that include scytophycins from Scytonema sp. and tolytoxin from Tolypothrix conglutinata var. colorata. The coming years may witness some interesting developments in biotechnology of blue green algae which may give a new dimension to the therapeutic utilization of blue green algae.

A comparative study on ethanol production from molasses using Saccharomyces cerevisiae and Zymomonas mobilis.

Abstract: Production of ethanol from molasses using Saccharomyces cerevisiae and Zymomonas mobilis was compared. Addition of different concentrations of ethanol in the medium markedly decreased the growth of both the cultures, however yeast was found to be more ethanol tolerant. There was no significant difference in ethanol production from molasses diluted to 5 - 15% (v/v), by both the cultures; however, S. cerevisiae produced more ethanol at sugar concentration above 15% (v/v). The temperature of 30°C was found optimum for maximum ethanol production from 20% (w/v) glucose and sucrose and 20% (v/v) molasses in 72 h.

Isolation and characterization of gut bacteria of millipede, Xenobolus carnifex (Fabricius)

Abstract: Bacterial strains from the gut of millipede, Xenobolus carnifex, were isolated and screened for their ability to produce different hydrolytic enzymes that are important in digesting the plant materials. Of 53 isolates, 48were cellulase and xylanase producers while 13 were amylase producers. Four strains produced proteinase. Three isolates namely, XGB12, XGB16 and XGB 41 had the ability to produce all the four enzymes. Based on the biochemical characteristics, the isolate XGB12 was confirmed as Proteus mirabilis while the isolates XGB16 and XGB41 were confirmed as Citrobacter freundii.

Removal of lead from aqueous solution by filamentous fungi

Abstract: Removal of lead from aqueous solution by live and dead biomass of different filamentous fungi, isolated from bio-contaminated diesel was studied. Bioaccumulation of lead by living fungal mycelia from 50 μg mL - 1 of lead solution (pH 5) was observed to be in the order of Aspergillus foetidus >Aspergillus terricola >Acremonium strictum >Cladosporium resinae >Phanerochaete chrysosporium >Aspergillus niger >Aureobasidium pullulans. Lead removal by non-living biomass of A. strictum, A. terricola and A. pullulans in batch mode was 84.7, 84 and 75.7% respectively. Removal of lead was more by dead fungal biomass than the living mycelia. Dried and pulverized fungal mycelia packed in a column removed up to 98% lead from a solution containing 25 μg lead mL - 1 at pH 5. Only A. foetidus showed lead adsorption after regeneration with 0.1 N HCl.

Gut bacterial flora of Helicoverpa armigera (Hub.) (Lepidoptera: Noctuidae)

Abstract: Twenty five isolates of bacteria representing eleven different genera belonging to diverse families were isolated and identified from different parts of the gut of Helicoverpa armigera (Hub.). Bacillus species dominated the bacterial flora. Total viable count (TVC) and heat stable count (HSC) showed higher incidence of spore forming bacteria in hind gut than the fore gut and mid gut.

Utilization of a Bacillus sp. APR4: protease in peptide synthesis

Abstract: Partially purified protease from Bacillus sp. APR4 was used to synthesize several dipeptide derivatives with different carboxyl and amino acid amide (Leu-NH 2 ) as nucleophile substrates in acetonitrile with a buffer concentration of 5% (v/v). Five dipeptides, N-Ac-CBz-Phe-Leu-NH 2 , N-Ala-Leu-NH 2 , L-Tyr-Leu-NH 2 , Z-L-Ser-Leu-NH 2 and Z-L-Pro-Leu-NH 2 were synthesized using this protease after 24 h reaction at 50°C.

Isolation of starch from potato using fungal enzyme

Abstract: Isolation of starch from potato using cellulase from Penicillium funiculosum was investigated. Hydrolysis of cellulose and rate of release of starch was assessed at various enzyme concentrations with different incubation time. The enzyme efficiently hydrolysed potato cell-wall and cell-envelope releasing the starch. About 68% starch was recovered in 6 h and the recovery was increased to 90% in 2 h by supplementing pectinase.

Degradation of phenol through ortho pathway by Pseudomonas sp. BC1

Abstract: Degradation of phenol by a bacterium BC1 is reported. The bacterium resembled to Pseudomonas pseudoalcaligenes in most of the morphological, biochemical and physiological characters. It was able to utilise phenol as sole source of carbon. Pseudomonas sp. BC1 was able to degrade phenol both in presence and absence of yeast extract at the rate of 5.87 and 5.43 mg h - 1 respectively. Crude cell extract showed the presence of catechol 1,2 dioxygenase, the ring cleavage enzyme. The activity of the enzyme was found to be 0.1035 m mole min - 1 mL - 1 , whereas specific activity was 0.03184 m mole min - 1 mg - 1 protein in the crude cell extract.

Application of monoclonal antibodies to flagellin of Salmonella typhi for its rapid detection in foods

Abstract: The aim of this study was to generate monoclonal antibodies (MoAbs) specific for H=d antigen of S. typhi and to develop a sandwich enzyme-linked immunosorbant assay (sELISA) for its rapid detection from food samples. Ninety eight hybridomas producing antibodies to group d flagella were generated and six stable clones were checked for specificity of their antibodies against various Salmonella serotypes and other closely related bacteria. Four of these clones were found to produce MoAbs specific for S. typhi and Salmonella serotypes having H = d antigens. A sELISA was developed utilizing antiflagellar polyclonal antibodies (PoAb) raised in a rabbit as the capture antibodies and 2/56 MoAb as detection antibody. sELISA had detection sensitivity of 10 5 cells mL - 1 in pure and mixed culture. The assay could detect 10 cfu of S. typhi bacteria g - 1 of chicken after 6 h growth in buffered peptone water. The assay developed was found specific for the detection of S. typhi (and other H=d Salmonella serotypes) and has the potential to be used as a rapid method for screening large numbers of samples for these organisms.

Biological activity of some substituted hydroxytriazenes

Abstract: Ten substituted hydroxytriazenes were synthesized, characterized and screened for their activity against five bacteria and five fungi. Out of ten compounds, four were found effective against some of the bacteria and fungi. One of the compounds, 3-hydroxy-3-phenyl-1-o-carboxyphenyltriazene was the best having MIC value 12.5 μg mL - L . Hydroxytriazenes can be further explored for this novel application apart from their analytical application as chelating agents.

Recovery of bacterial and mycotic fish pathogens from carps and other fish in Himachal Pradesh

Abstract: Of 156 carps and other fish both fresh and moribund, 81 showed visible macro-lesions. Samples of various organs of these fish contained bacteria like Aeromonas, Enterobacter, Escherchia and Vibrio.

Intrinsic antibiotic resistance and biochemical characteristics of Anabaena azollae isolated from Azolla - cultures

Abstract: Cultures of algal symbiont, Anabaena azollae were isolated from four different Azolla- species viz., A. filiculoides, A. microphylla, Azolla hybrids viz., TNAU and Rongping and were designated as A. azollae-AF, A. azollae-AM, A. azollae-TM and A. azollae - RP respectively. The isolated algal strains were examined for their intrinsic resistance to antibiotics and biochemical characteristics. A. azollae-AF and A. azollae-RP showed almost identical pattern of resistance to most of the antibiotics tested, while A. azollae-AM showed a different pattern. A. azollae-AM was able to tolerate maximum concentration of the antibiotics, while A. azollae-TH showed the least resistance. The free-living A. variabilis was found to be more resistant than isolates of A. azollae to different antibiotics. Both A. azollae and A. variabilis were highly sensitive to even low concentrations of erythromycin and streptomycin. A. azollae-AF recorded maximum heterocyst frequency, nitrogenase activity, ammonia excretion, ammonical N, protein, total N, K, chlorophyll a, iron and zinc content. The pigment, reducing and total sugars, and P were found to be higher in A. azollae-TH which had least heterocysts than other strains. A. azollae-AM recorded maximum Cu and Mn content. The results revealed biochemical diversity among the strains of A. azollae.

In vitro interaction of fungal antagonists with Phomopsis theae, the causal agent of collar canker disease in tea

Abstract: Interaction between the collar canker pathogen Phomopsis theae and fungal antagonists like Trichoderma harzianum and Gliocladium virens was studied in vitro. Dual culture studies, morphological interaction and antibiosis revealed the antagonistic properties. Interaction studies on the tea stem bits further confirmed this and revealed that T. harzianum and G. virens were able to suppress the growth and reproduction of P. theae. The results indicated the potential of these organisms as biocontrol agents against P. theae.

Antimicrobial activity of Caesalpina digyna on some human pathogenic microorganisms

Abstract: Antimicrobial activity of Caesalpina digyna was evaluated on some human pathogenic microorganisms. Aqueous extracts of dry fruits and seeds at various concentrations were assessed by disc diffusion method. The fruit extract showed broad spectrum of antimicrobial property and was more effective than the seed extract. Fruit extract at 2 mg mL - 1 was inhibitory to all the microorganisms. Staphylococcus aureus was inhibited the most and Pseudomonas aeruginosa the least. Salmonella typhi was inhibited the most and Yersinia enterocolitica the least by the seed extract. The minimal inhibitory concentration of fruit extract ranged from 200 - 800 μg mL - 1 where as for the seed extract it was 500 - 3000 μg mL - 1 .

Bacillus coagulans, a highly salt tolerant bacterium isolated from native soil of Rajasthan

Abstract: Highly salt tolerant, gram positive, aerobic and rod shaped bacterium was isolated from native soil (EC 2.2, pH 7.8) of Rajasthan near Jaipur, India. The bacterium was capable of growing very well in LB medium containing up to 6% NaCl (5.9 A 6 0 0 ). At higher concentration up to 10%, the growth was moderate to sparse. It was able to grow at temperature from 15 to 37°C and pH from 6.8 to 11. Through morphological and biochemical tests, the bacterium was identified as Bacillus coagulans. The bacterium was salt excluder and had proline mediated osmoregulatory mechanism for its salt tolerance.

Serogroups and drug sensitivity of Escherichia coli isolated from drinking water sources

Abstract: A total of 56 Escherichia coli-strains were isolated from different drinking water sources of greater Guwahati area. The isolates were typed into 10 serogroups. The serogroups O8,O60 and O68 occurred frequently followed by O14 and O102. The antibiogram study showed that the susceptibility of the isolates was highest to ciprofloxacin (89%), gentamicin (89%), norfloxacin (86%) and trimethoprim (86%), and lowest to cefotaxime (4%).

Detection of blackeye cowpea mosaic Potyvirus (BLCMV) in leaves and seeds of cowpea.

Abstract: Blackeye cowpea mosaic potyvirus (BLCMV) was detected in 128 out of 148 leaf and 17 out of 65 seed samples of cowpea based on indicator plant test and enzyme-linked immunosorbent assay (ELISA). Seed samples collected fromMysore showed maximum of 7% seed transmission. Concentration of BLCMV was more in the plants showing distortion symptoms. BLCMV concentration was higher in the artificially inoculated plants when compared to the naturally infected plants. ELISA detected a minimum of two infected seedlings in a sample of five. BICMV was detected in all the floral parts of an infected flower. It was also detected in embryonic axis and cotyledons of infected seeds but not in the seed coat.

Production of lactic acid during bioremediation of anaerobically digested molasses spent wash

Abstract: Lactic acid bacteria were isolated from soil by enrichment culture technique using anaerobically digested molasses spent wash (ADMSW), which was obtained from a biomethanation plant. The bacterial isolates could grow in 25% (v/v) ADMSW medium supplemented with 2% carbon, 4% moong bean sprouts (w/v) and 0.15% diammonium phosphate. Due to fermentation, there was reduction of COD by 41% and colour by 57% in the effluent. During the bioremediation process, lactic acid with an average yield of 15.4 gL - 1 was obtained as a byproduct.

Use of amylolytic cultures of Aspergillus for treatment of wastewater from potato processing

Abstract: Nine strains of four species of Aspergillus were screened for their amylolytic activity. Four strains having high amylolytic activity were selected and examined for treatment of wastewater from potato processing unit (PPW). A. foetidus MTCC508 and A. niger ITCC2012 were found to be promising for treating PPW, as they could bring 60 - 63% reduction in COD. Mixed culture of these two strains could synergistically reduce the COD by 90% within 60 h of incubation.

Characterization of biosurfactant synthesis in a hydrocarbon utilizing bacterial isolate

Abstract: Remediation of petroleum-spoilt soil depends on the metabolic activity of autochthonous microbial flora at the site of contamination. Presence of surface-active agents can enhance the microbial metabolic process by makingthe contaminant more easily available to all the organisms at the site. By inoculating a hydrocarbon degrading bacterial isolate the rate of diesel degradation was enhanced. This bacterium responded to hydrophobic substrates by producing biosurfactant. Vegetable oils containing unsaturated fatty acids, such as sunflower oil were very good inducers of the biosurfactant activity.

Development of transformation system for entomopathogenic fungus Metarhizium anisopliae (ENT 12) based on cnx - gene

Abstract: We report here the development of a heterologous transformation system for entomopathogenous fungus Metarhizium anisopliae using the cnx - gene (cofactor for nitrate and xanthine dehydrogenase) of Aspergillus nidulans. Mutant defective in the nitrate assimilation pathway was selected on the basis of chlorate (KClO 3 ) resistance by conventional means. Screening procedure was easy to differentiate nitrate reductase apoprotien structural gene mutants (niaD - ) from molybdenum cofactor gene mutants (cnx - ) as unlike most filamentous fungi, these mutants failed to grow on minimal medium containing hypoxanthine as a sole source of nitrogen. Plasmid clone carrying the cnx - gene (designated as cnx H) was able to transform stable cnx - mutants of M. anisopliae at a low frequency of 2 - 3 transformants μg - 1 DNA. Transformants were easily visible since the background growth was low and no abortives were observed. Most of them were mitotically stable.

Effect of dual inoculation of Bradyrhizobium japonicum and Azotobacter chroococcum

Abstract: The inoculation effect of Bradyrhizobium japonicum and Azotobacter chroococcum on soybean (Glycine max (L) Merrill var. Ransom was studied. Dual inoculation proved best in all the plant growth parameters. Inoculation withAzotobacter alone was also little better than un-inoculated control.

In vitro susceptibility of chloroquine (4-aminoquinolines) against pathogenic bacteria

Abstract: Chloroquine, an antimalaria drug, has also been used for the treatment of acanthamoeba, Clonorchis sinesis, taeniasis, rheumatoid arthritis and fungal infections. It has also been used as an immunomodulator. By using discdiffusion technique chloroquine phosphate was found to show a broad range antibacterial activity. It was found effective against Bacillus subtilis, Escherichia coli, Haemophilus influenzae, Proteus vulgaris, Pseudomonas aeruginosa, Salmonella typhi, S. enteritidis and Staphylococcus aureus. Neisseria catarrhalis and P. fluorescens were found resistant.

Genetically engineered Pseudomonas systems and their application in bioremediation

Abstract: Among the biodegrading bacteria investigated in the past 20 years, Pseudomonas spp. have been found to be the most versatile because of the vast array of their plasmid and chromosomal encoded catabolic genes capable of degrading a variety of chloro-aliphatics and aromatics. Over the years, efforts have been made to engineer a single Pseudomonas 'superbug' which can simultaneously catabolize a large number of these hazardous compounds like 4-chlorobenzoate, 4-chlorophenol and p-cresol, p-ethyltoluene, toluene, phenol, benzene and o-cresol. However, there is a considerable concern that these genetically engineered microorganisms (GEMs), would harm the environment by spreading their genetic material to native microbes which might change the microbial ecology in and around the area of their application. Although, currently there is no report of gene flow between kingdoms, reports of inter- and intra- specific horizontal gene transfer among microorganisms are plenty. Accordingly, scientists have designed and used specialized host-vector systems for engineering Pseudomonas - strains employing plasmids and transposons like 'field application vectors' or 'suicide containment systems'.