Physicochemical behavioral changes in consort with nitrogen metabolism of cyanobacterium Anabaena PCC 7120 under arsenite regimes.

The present study was undertaken to investigate the arsenite (As III)-induced changes in the diazotrophic cyanobacterium Anabaena PCC 7120. It was observed that the growth of cyanobacterial decreased with increase in As (III) concentration. The cells exposed to As (III) showed morphological variation (deformity) due to the formation of deeper constrictions in vegetative cells. Strain showed increased heterocyst differentiation (1.6-fold higher) whereas decreased nitrogenase activity at the concentration of 40 ppm As (III). The activities of NR, NiR, urease and GS decreased with increase in As (III) concentrations and attained their minimum levels at 40 ppm of As (III). The Ca2+-dependent ATPase activity increased with increase in As (III) concentration and attained its about 2.72-fold higher level at 40 ppm of As (III). In contrast, sharp decline in Mg2+-dependent ATPase activity (28%) was recorded at 1 ppm of As (III) over untreated control. The rates of photosynthetic O2 evolution and respiration decreased with increase in As (III) concentration and attained its minimal level at 40 ppm of As (III). Therefore, this study highlighted arsenite regimes efficiently correlated with behavioral changes in consort with strain.

Isolation and identification of allelochemicals produced by B. sonorensis for suppression of charcoal rot of Arachis hypogaea L.

Bacillus sonorensis MBCU2 isolated from vermicompost-amended soil from Gujarat, India showed most antagonistic activity against Macrophomina phaseolina by dual culture screening. The culture supernatant of MBCU2 completely suppressed the mycelia growth of pathogen, indicating that suppression was due to the presence of allelochemicals in the culture filtrate. Results of scanning electron microscopy revealed that MBCU2 caused morphological alteration in mycelia of M. phaseolina as evident by hyphal lysis and perforation. Lipopeptides (iturin A and surfactin) produced by MBCU2 were detected and identified by MALDI-TOF-MS as well as liquid chromatography coupled with ESI-MS/MS. Pot trial studies conducted by seed bacterization with MBCU2 resulted in statistically significant increase in Arachis hypogaea L. vegetative growth parameters such as root length (91%), shoot length (252%), fresh weight (71%), dry weight (57%), number of pod (128%), and number of seed (290%) in M. phaseolina infested soil over control as well as decreased M. phaseolina disease severity. We suggest that allelochemicals production can be linked to the mechanism of protection of A. hypogaea L. from M. phaseolina by B. sonorensis MBCU2.

Bioactive mushroom polysaccharides as antitumor: an overview.

Immuno-therapies are gaining more importance to treat certain forms of cancer. The goal of therapies is to enhance person's own IgG, IgA, IgM, IgD, IgE and macrophages to combat with neoplastic cells hence the effectiveness of the immune system. Since, early civilization mushrooms are considered as potent food as well as medicine. Mushrooms are well known for their bioactive compounds such as chizophyllan, lentinan, grifolan, PSP (polysaccharide-peptide complex) and PSK (polysaccharide-protein complex) which are considered as medicines against melignancy. They prevent oncogenesis by the direct effect on tumor metastasis and exhibits antitumor effects by the induction of immune response in host. Mushroom polysaccharides have promising future for treatment of cancers due to their mode of action and efficacy. Also there are some hurdles during this treatment, but it will start a new era of safer and effective medicine based on mushroom polysaccharides.

Development of herbal disinfectants formulation for mopping households and its antibacterial activity.

There are many household products like detergents, disinfectants, stain removers and cosmetics releasing chemicals that may be harmful to human health as well as cause hazardous effect on environment. Global world is now focusing on use of herbal products. They are eco-friendly and more suitable to household applications than chemicals. The present study focused on preparation of three plant-based formulations for household cleaning applications. Result showed antibacterial activity against most commonly available microbes viz. Escherichia coli and Staphylococcus aureus. This is the first report of Terminalia chebula for preparation of herbal cleaners.

Multifarious allelochemicals exhibiting antifungal activity from Bacillus subtilis MBCU5.

A potential antagonist, designated strain Bacillus subtilis MBCU5 was previously isolated from vermicompost-amended soils of Gandhinagar, Gujarat, India. Crude allelochemicals from strain MBCU5 displayed strong antifungal activity against Macrophomina phaseolina as well as Rhizoctonia solani. These crude allelochemicals were tentatively identified as iturin, fengycin and surfactin through TLC and HPTLC analysis. Lipopeptides produced by MBCU5 were identified by MALDI-TOF-MS and LC-ESI-MS/MS analysis showed that iturin homologues (m/z 1020-1120), surfactin (m/z 1008.7 and m/z 1022.7), fengycin A and fengycin B (m/z 1400-1550) types of allelochemicals which are responsible for antifungal activity against pathogens. PCR analysis showed presence of genes (i.e. Iturin A synthetase KJ531680 and Surfactin synthetase KJ601726) involved in the biosynthesis of allelochemicals. Many reports showed lipopeptides from Bacillus species; this is the first report executed of multifarious allelochemicals from vermicompost-amended soil due to the presence of predominant Bacillus species.

Role of allelochemicals in plant growth promoting rhizobacteria for biocontrol of phytopathogens.

Soil borne fungal diseases pose serious constraints on agro-productivity. Biological control is non-hazardous strategy to control plant pathogens and improve crop productivity. PGPR (plant growth promoting rhizobacteria) have long been used as plant disease control agents. PGPR produced a wide range of secondary compounds that may act as signals--that is, allelochemicals that include metabolites, siderophores, antibiotics, volatile metabolites, enzymes and others. Their mode of action and molecular mechanisms provide a great awareness for their application for crop disease management. The present review highlights the role of PGPR strains, specifically referring to allelochemicals produced and molecular mechanisms. Further research to fine tune combinations of allelochemicals, plant-microbe-pathogen interaction will ultimately lead to better disease control.