Antimicrobial properties of chitosan nanoparticles: Mode of action and factors affecting activity

The present investigation describes the synthesis and characterization of novel biodegradable nanoparticles based on chitosan for biomedical applications. The presence of primary amine groups in repeating units of chitosan grants it several properties like antibacterial activity, antitumor activity and so on. Chitosan forms nanoparticles spontaneously on the addition of polyanion tripolyphosphate which has greater antimicrobial activity than parent chitosan. In the present study, chitosan nanoparticles (ChNP) were prepared by the ionic gelation method. The physiochemical characteristics of nanoparticles were analyzed using XRD, SEM, FTIR. The antibacterial activity of chitosan nanoparticles against medical pathogens Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa was evaluated by calculation of minimum inhibitory concentration (MIC) and compared with chitosan and chitin activity. The mode of action and factors affecting antibacterial activity were also analyzed. ChNP compounds exhibited superior antimicrobial activity against all microorganisms in comparison with chitosan and chitin. The antibiofilm activity was studied using crystal violet assay and growth on congo red agar. The study is thus a good demonstration of the applicability of chitosan nanoparticles as an effective antimicrobial agent with antibiofilm activity as well.     

Effect of single and dual phosphate-solubilizing bacterial strain inoculations on overall growth of mung bean plants

Available phosphorus is limiting in most cultivable soils in several parts of India, including Rajasthan. Four phosphate-solubilizing bacterial strains viz. Pseudomonas fluorescens BAM-4, Burkholderia cepacia BAM-6, B. cepacia BAM-12 and Aeromonas vaga BAM-77 were isolated from the rhizosphere of pearl millet (Pennisetum glaucum, cv. Raj 171), mung bean (Phaseolus aureus, cv. RMG 492) and sesame (Sesamum indicum, cv. RT 46). To the best of our knowledge, this is the first report on phosphate solubilization by Aeromonas vaga. Seed inoculation of mung bean with or without tricalcium phosphate (TCP) was performed to study the effect of single and dual bacterial inoculations in pot trials having sterilized sandy loam soil, and was found to enhance the growth and yield of plants. The results were on a par with chemical fertilizer, single superphosphate (SSP) and commercial biofertilizers, PSB (Bacillus polymyxa) and MC (Pseudomonas striata), used as standard reference. Addition of TCP to soil gave better results and dual inoculation was more effective than single inoculation of bacteria. Among the four strains studied, A. vaga and P. fluorescens were found to be more valuable as single inoculants in terms of plant growth, whereas in combination treatments, P. fluorescens along with B. cepacia and A. vaga performed very well both in the presence and absence of TCP.     

Improvement of Dry‐Fractionation Ethanol Fermentation by Partial Germ Supplementation

Ethanol fermentation of dry‐fractionated grits (corn endosperm pieces) containing different levels of germ was studied with the dry‐grind process. Partial removal of the germ fraction allows for marketing the germ fraction and potentially more efficient fermentation. Grits obtained from a dry‐milling plant were mixed with different amounts of germ (2, 5, 7, and 10% germ of the total sample) and compared with control grits (0% germ). Fermentation rates of germ‐supplemented grits (2, 5, 7, and 10% germ) were faster than control grits (0% germ). Addition of 2% germ was sufficient to achieve a high ethanol concentration (19.06% v/v) compared with control grits (18.18% v/v). Fermentation of dry‐fractionated grits (92, 95, and 97% grits) obtained from a commercial facility was also compared with ground whole corn (control). Fermentation rates were slower and final ethanol concentrations were lower for commercial grits than the control sample. However, in a final experiment, commercial grits were subjected to raw starch hydrolyzing (RSH) enzyme, resulting in higher ethanol concentrations (20.22, 19.90, and 19.49% v/v for 92, 95, and 97% grits, respectively) compared with the whole corn control (18.64% v/v). Therefore, high ethanol concentrations can be achieved with dry‐fractionated grits provided the inclusion of a certain amount of germ and the use of RSH enzyme for controlled starch hydrolysis.     

Phytotherapy and combined nanoformulations as a promising disease management in aquaculture: a review

Aquaculture International - Aquaculture-based foods have enriched nutritional and medicinal value to meet the needs of the global population. Recently, improper maintenance of aquatic organisms in...     

Environmentally benign scouring of wool fibers using mesophile acidic lipase

Surfaces of raw wool fibers possess high amounts of greasy substances that need to be removed prior to further processing. Acidic lipases using Bacillus licheniformis (MTCC 2618) were produced with the optimum activity levels closer to the room temperature. Scouring of wool fibers using mesophile acidic lipase has been attempted, in the present work, as an alternative to the existing alkaline treatment and the samples were assessed in terms of weight loss, moisture regain, tenacity, elongation, surface appearance, and friction of the fibers. The lipase scoured wool fibers showed moisture regain and weight loss values comparable to that of alkaline treatment, with lower static and dynamic frictional coefficients. Higher tenacity and elongation values were observed in the lipase scoured fibers compared to the alkaline scoured samples and clear appearance of the surface, compared to the raw wool fibers, was also observed in the lipase scoured samples.     

Guar genes to genome and meta-analysis of SSR markers in sequencing studies

Genetic Resources and Crop Evolution - Guar (Cyamopsis tetragonoloba (L.) Taub.), or cluster bean, traditionally grown for vegetable and fodder, has gained commercial importance across the globe...     

Effect of potential bioinoculants and organic manures on root‐rot and wilt,growth, yield and quality of organically grown Coleus forskohlii in a semiarid tropical region of Bangalore (India)

Based on earlier results obtained in pot experiments, 2‐year field experiments were conducted with five bioinoculants and neem cake under organic field conditions (with vermicompost as a nutritional supplement) to evaluate their potential to control root‐rot and wilt (a complex problem involving Fusarium chlamydosporum and Ralstonia solanacearum) of the medicinal plant Coleus forskohlii. Plants treated with arbuscular mycorrhizal fungus (Glomus fasciculatum), neem cake or Pseudomonas fluorescens showed significantly increased plant height (15–31%), plant spread (25–33%), number of branches (63–67%) and dry root (129–200%) yields, and reduced disease incidence (47–50%) compared to controls. Increases in yields were reflected by increases in N (51–81%), P (17–76%) and K (44–74%) uptake. The forskolin content of the roots was found not to be affected by any of the bioinoculants, but forskolin yield (calculated) was increased significantly by treatment with G. fasciculatum (227%), neem cake (222%) or P. fluorescens (159%).