Development of novel simple sequence repeat markers in bitter gourd (Momordica charantia L.) through enriched genomic libraries and their utilization in analysis of genetic diversity and cross-species transferability.

Microsatellite or simple sequence repeat (SSR) markers are the preferred markers for genetic analyses of crop plants. The availability of a limited number of such markers in bitter gourd (Momordica charantia L.) necessitates the development and characterization of more SSR markers. These were developed from genomic libraries enriched for three dinucleotide, five trinucleotide, and two tetranucleotide core repeat motifs. Employing the strategy of polymerase chain reaction-based screening, the number of clones to be sequenced was reduced by 81 % and 93.7 % of the sequenced clones contained in microsatellite repeats. Unique primer-pairs were designed for 160 microsatellite loci, and amplicons of expected length were obtained for 151 loci (94.4 %). Evaluation of diversity in 54 bitter gourd accessions at 51 loci indicated that 20 % of the loci were polymorphic with the polymorphic information content values ranging from 0.13 to 0.77. Fifteen Indian varieties were clearly distinguished indicative of the usefulness of the developed markers. Markers at 40 loci (78.4 %) were transferable to six species, viz. Momordica cymbalaria, Momordica subangulata subsp. renigera, Momordica balsamina, Momordica dioca, Momordica cochinchinesis, and Momordica sahyadrica. The microsatellite markers reported will be useful in various genetic and molecular genetic studies in bitter gourd, a cucurbit of immense nutritive, medicinal, and economic importance.

Surface-active potential of biosurfactants produced in curd whey by Pseudomonas aeruginosa strain-PP2 and Kocuria turfanesis strain-J at extreme environmental conditions.

Surface-active potential of biosurfactants produced cost-effectively in curd whey by Pseudomonas aeruginosa strain-PP2 and Kocuria turfanesis strain-J were tested using parameters viz. surface tension (ST) reduction, F(CMC) (highest dilution factor to reach critical micelle concentration) and emulsification index (EI-24) of pesticides; monocrotophos and imidacloprid at extreme environmental conditions. Results have shown that ST reduction of biosurfactants was stable at pH 2-11. High F(CMC) of the biosurfactant in the fermented whey at low pH improved emulsification of pesticides. ST marginally increased at 5% and 15% NaCl, resulting in high EI-24 and F(CMC). Over a range of temperatures 30-121 °C, ST remained low with a higher F(CMC) and EI-24 at 60 °C than at 121 and 30 °C. The biosurfactants have shown differences in their surface-active property and have marked specificity to emulsify pesticides in extreme environmental conditions.

Selection of indicator bacteria based on screening of 16S rDNA metagenomic library from a two-stage anoxic-oxic bioreactor system degrading azo dyes.

Dye degradation has gained attention of late due to indiscriminate disposal from user industries. Enhancing efficiency of biological treatment provides a cheaper alternative vis-à-vis other advanced technologies. Dye molecules are metabolized biologically via anoxic and oxic treatments. In this study, bacterial community surviving on dye effluent working in anoxic-oxic bioreactor was analyzed using 16S rDNA approach. Azo-dye decolorizing and degrading bacterial community was enriched in lab-scale two-stage anoxic-oxic bioreactor. 16S rDNA metagenomic libraries of enriched population were constructed, screened and phylogenetically analyzed separately. Removal of approximately 35% COD with complete decolorization was observed in anoxic bioreactor. Process was carried out by uncultured gamma proteobacterium constituting 48% of the total population and 12% clones having homology to Klebsiella. Aromatic amines generated during partial treatment under anoxic bioreactor were treated by aerobic population having 72% unculturable unidentified bacterium and rest of the population consisting of Thauera sp., Pseudoxanthomonas sp., Desulfomicrobium sp., Ottowia sp., Acidovorax sp., and Bacteriodetes bacterium sp.

Isolation, evaluation and characterization of Bacillus subtilis from cotton rhizospheric soil with biocontrol activity against Fusarium oxysporum.

Present investigation is based on the isolation of Bacillus subtilis from cotton rhizosphere and their evaluation as biocontrol agent against Fusarium oxysporum. The production of extracellular hydrolytic enzyme was studied for determining the antagonism. 43% of 21 isolates were identified under the B. subtilis group on the basis of biochemical characterization. 38% isolates showed competitive activity against Fusarium oxysporum and exhibit more than 50% mycelial inhibition in dual culture bioassay. The pot assay of cotton by seed treatment and soil amendment technique under green house condition showed the competent activity of the isolates in preventing the wilting of cotton seedlings due to F. oxysporum infection. SVI values of 30 day old seedlings indicated that the soil inoculation with B. subtilis BP-2 and seed treatment with B. subtilis BP-9 significantly promoted the growth of cotton seedlings. RAPD profiling revealed the diversity in the Bacillus subtilis group, ranging from 10 to 32%. The discriminative pattern among the isolates belonging to the same species was validated by 16S rDNA partial sequencing which identified them into four different strains of B. subtilis.

Kinetic study approach of remazol black-B use for the development of two-stage anoxic-oxic reactor for decolorization/biodegradation of azo dyes by activated bacterial consortium.

The laboratory-isolated strains Pseudomonas aeruginosa, Rhodobacter sphaeroides, Proteus mirabilis, Bacillus circulance, NAD 1 and NAD 6 were observed to be predominant in the bacterial consortium responsible for effective decolorization of the azo dyes. The kinetic characteristics of azo dye decolorization by bacterial consortium were determined quantitatively using reactive vinyl sulfonated diazo dye, remazol black-B (RB-B) as a model substrate. Effects of substrate (RB-B) concentration as well as different substrates (azo dyes), environmental parameters (temperature and pH), glucose and other electron donor/co-substrate on the rate of decolorization were investigated to reveal the key factor that determines the performance of dye decolorization. The activation energy (E(a)) and frequency factor (K(0)) based on the Arrhenius equation was calculated as 11.67 kcal mol(-1) and 1.57 x 10(7)mg lg MLSS(-1)h(-1), respectively. The Double-reciprocal or Lineweaver-Burk plot was used to evaluate V(max), 15.97 h(-1) and K(m), 85.66 mg l(-1). The two-stage anoxic-oxic reactor system has proved to be successful in achieving significant decolorization and degradation of azo dyes by specific developed bacterial consortium with a removal of 84% color and 80% COD for real textile effluents vis-à-vis >or=90% color and COD removal for synthetic dye solution.

Decolorization of azo dyes and simulated dye bath wastewater using acclimatized microbial consortium--biostimulation and halo tolerance.

Anaerobic acclimatization of activated sludge from a textile effluent treatment plant to high concentration of RB5 could effectively decolorize RB5 dye solution. The strains viz. Pseudomonas aeruginosa and Bacillus circulans and other unidentified laboratory isolates (NAD1 and NAD6) were predominantly present in the microbial consortium. The conditions for efficient decolorization, biostimulation to increase effectiveness of microbial consortium, its tolerance to high salt concentration and non-specific ability towards decolorization of eight azo dyes, are reported. The optimum inoculums concentration for maximum decolorization were found to be 1-5 ml of 1800+/-50 mg l(-1) MLSS and 37 degrees C, respectively. The decolorization efficiency was 70-90% during 48 h. The biomass showed efficient decolorization even in the presence of 10% NaCl, as tested with RB5. In the presence of flavin adenine dinucleotide (FAD) more than 99% decolorization occurred in 8h. The decolorization of RB5 was traced to extracellular enzymes. The effectiveness of acclimatized biomass under optimized conditions towards decolorization of two types of synthetic dye bath wastewaters that were prepared using chosen azo dyes is reported.