Biochemical, pathological and molecular characterisation of Phomopsis vexans: A causative of leaf blight and fruit rot in brinjal.

The pathogen Phomopsis vexans causes leaf blight, fruit rot, and damping off in brinjal plants, all of which are extremely detrimental. The pathogen affects host plant photosynthetic efficiency and fruit quantity and quality. An appreciation of the pathogenicity of P. vexans is essential for the effective control of infections in the field. Consequently, the goal of this study was to characterise P. vexans in terms of their biochemistry, molecular diversity, and pathogenicity. In terms of cellulase (97.7 U), catalase (12.2 U), and ascorbate peroxidase (147.3 U) activity, isolate PV1 performed best, followed by PV5 (CL-97.0 U, CAT-11.1 U and APX-144.4 U), and PV8 (CL-88.8 U, CAT-9.8 U and APX-141.9 U). In a greenhouse pathogenicity test, isolate PV1 had the highest incidence (97%) and severity (88.6%) of disease, whereas isolate PV6 showed the lowest incidence (57.2%) and severity (70%) of disease. The biochemical enzyme activity of P. vexans corresponds well with its greenhouse pathogenicity results, and its combination can be exploited to identify pathogenic P. vexans isolates. Using RAPD and ISSR primers, molecular characterisation indicated genetic diversity but could not distinguish isolates by geographical origin or pathogenicity. The pathogen P. vexans was verified by ITS1 and ITS4 molecular analysis, and the sequences were subsequently deposited in the NCBI database. In conclusion, the enzyme activity relevant to pathogenicity (CL, CAT and APX) in conjunction with the invivo pathogenicity assay might be utilised to differentiate between pathogenic (virulent) and non-pathogenic (avirulent) P. vexans isolates and develop suitable disease management strategies.

Biodegradable chitosan-sodium alginate-oleic acid nanocarrier promotes bioavailability and target delivery of lutein in rat model with no toxicity.

Efficient delivery of macular carotenoid lutein to target retinal tissue is possible with enhanced intestinal uptake remains a major challenge owing to the polarity, sensitivity to light, heat and solubility. In this study, to overcome such constraints, biodegradable polymers chitosan-sodium alginate-oleic acid based nano-carrier loaded with lutein (LNCs) was prepared and safety efficacy was examined in vivo. Acute-toxicity of LNCs (0.1, 1, 10 and 100 mg/kg body weight) revealed that the LD50 of LNCs was higher than 100 mg/kg body weight. In subacute-toxicity of LNCs (1 and 10 mg/kg body weight) revealed no mortality with no morphological and clinical changes in rats. Histology, haematology and biochemical analysis of urine and plasma confirmed no toxicity of LNCs compared to control. Post-prandial plasma and tissue (retina) levels of lutein from LNCs were higher. Results demonstrate increased bioavailability of lutein from LNCs with no toxicity suggests applications in food and pharma.

Chitosan-oleic acid-sodium alginate a hybrid nanocarrier as an efficient delivery system for enhancement of lutein stability and bioavailability.

Lutein is a hydrophobic antioxidant carotenoid with proven retinal and macular protection against oxidative stress. However, low aqueous solubility and bioavailability limit its clinical application. Hence, focus of the study was to improve the solubility and bioavailability of lutein by using a chitosan-oleic acid-sodium alginate-based nano-carrier system (LNCs). LNCs were prepared by ionic gelation and optimized by Plackett-Burman factorial algorithm. The size and zeta potential of LNCs were characterized by electron microscopy and dynamic light scattering. LNCs were within a size range of 40-160 nm with a desired zeta potential of +45 ± 5 mV and PDI of 0.174 ± 0.02. Further, LNCs displayed 1000-fold higher aqueous solubility with controlled and sustained release kinetics in vitro. Compared to micellar lutein, higher intracellular transport (40%) of lutein from LNCs in Caco-2 cells. Oral gavage of single dose of LNCs in rats resulted in higher (128.3%) bioavailability of lutein compared to micellar lutein. Further, a dose-dependent increase in plasma (135.20, 165.30 nmol/mL) and eyes (1.51 & 3.98 µg/g) was observed upon oral gavage of LNCs (10 and 100 mg/kg BW). Results demonstrate higher solubility and bioavailability of lutein from LNCs and hence could be an efficient therapeutic tool to conquer macular degeneration and retinopathy.

Characterization of non-aflatoxigenic strains of Aspergillus flavus as potential biocontrol agent for the management of aflatoxin contamination in groundnut.

In the present study, nine non-aflatoxigenic Aspergillus flavus strains were evaluated for their potential to reduce A. flavus infection and aflatoxin contamination in groundnut. Genetic characterization of these strains revealed six different deletion patterns (A-F) for thirteen examined genes from the aflatoxin biosynthesis pathway. Strain AFGS5 recorded maximum number of gene deletion (F) which included 12 out of 13 tested genes. Our findings indicated that aflR was the most frequently absent gene among the observed deletion patterns. A dendrogram inferred from combining random amplified polymorphic DNA and microsatellite data showed three of the non-aflatoxigenic strains segregating from other sampled isolates (aflatoxigenic and non-aflatoxigenic) tested. Greenhouse experiments, involving non-aflatoxigenic strains as biocontrol agents resulted in two strains, AFGS5 and AFGS12, which significantly reduced the population of aflatoxigenic fungi and the level of total aflatoxins in the rhizosphere/geocarposphere of soil samples as well as in groundnut seeds. Based on our findings, the use of these native non-aflatoxigenic strains; AFGS5 or AFGS12 in particular, as biopesticides could offer efficacious mitigation of aflatoxin contamination.