ABSTRACT
BACKGROUND: Lactobacillus delbrueckii was one of the most common milk lactic acid bacterial strains (LAB) which characterized as probiotic with many health influencing properties. RESULTS: Among seven isolates, KH1 isolate was the best producer of folic acid with 100 µg/ml after 48 h of incubation; FolE gene expression after 24 h of incubation was in the highest value in case of KH1 with three folds. Lactose was the best carbon source for this KH1, besides the best next isolates KH80 and KH98. The selected three LAB isolates were identified through 16S rDNA as Lactobacillus delbrueckii. These three isolates have high tolerance against acidic pH 2-3; they give 45, 10, and 22 CFUs at pH 3, besides 9, 6, and 4 CFUs at pH2, respectively. They also have resistance against elevated bile salt range 0.1-0.4%. KH1 recorded 99% scavenging against 97.3% 1000 µg/ml ascorbic acid. Docking study exhibits the binding mode of folic acid which exhibited an energy binding of - 8.65 kcal/mol against DHFR. Folic acid formed four Pi-alkyl, Pi-Pi, and Pi-sigma interactions with Ala9, Ile7, Phe34, and Ile60. Additionally, folic acid interacted with Glu30 and Asn64 by three hydrogen bonds with 1.77, 1.76, and 1.96 Å. CONCLUSION: LAB isolates have probiotic properties, antioxidant activity, and desired organic natural source for folic acid supplementation that improve hemoglobin that indicated by docking study interaction.
ABSTRACT
Rice is a major food crop that has a critical role in ensuring food security for the global population. However, major abiotic stresses such as salinity and alkalinity pose a major threat to rice farming worldwide. Compared with salinity stress, there is limited progress in elucidating the molecular mechanisms associated with alkalinity tolerance in rice. Since both stresses coexist in coastal and arid regions, unraveling of the underlying molecular mechanisms will help the breeding of high-yielding stress-tolerant rice varieties for these areas. This study examined the morpho-physiological and molecular response of four rice genotypes to both salinity and alkalinity stresses. Geumgangbyeo was highly tolerant and Mermentau was the least tolerant to both stresses, while Pokkali and Bengal were tolerant to only salinity and alkalinity stress, respectively. A set of salinity and alkalinity stress-responsive genes showed differential expression in the above rice genotypes under both stress conditions. The expression patterns were consistent with the observed morphological responses in these rice genotypes, suggesting the potential role of these genes in regulating tolerance to these abiotic stresses. Overall, this study suggested that divergence in response to alkalinity and salinity stresses among rice genotypes could be due to different molecular mechanisms conferring tolerance to each stress. In addition to providing a basis for further investigations into differentiating the molecular bases underlying tolerance, this study also emphasizes the possibilities of developing climate-resilient rice varieties using donors that are tolerant to both abiotic stresses.
