The present study aims to assess the physicochemical properties and prevalence of microbial communities in soils samples collected from different locations of Cachar district, Assam, India. Bacterial communities in the soil were screened by morphological, biochemical and 16S rDNA sequence analysis and were identified as Bacillus megaterium, Bacillus cereus, Pseudomonas aeruginosa and Chromobacterium pseudoviolaceum. High concentrations of toxic metals negatively affect bacterial growth, and therefore, the minimum inhibitory concentration of isolated bacteria was determined against Cd, Pb, Fe and Cu by agar dilution technique. Co-resistance of antibiotic was also determined, which demonstrated that most of the metal-tolerant isolates were resistant to Methicillin and Penicillin. However, P. aeruginosa showed resistance to other antibiotics such as Cefdinir, Ampicillin, Kanamycin, Rifampicin and Vancomycin. The development and evolution of antibiotic resistance in soil bacteria occurs very likely naturally as a result of unethical and non-scientific disposal of toxic substances and industrial discharge, which also includes heavy-metal effluents and other clinical by-products. Therefore, pragmatic measures must be taken to limit the spread of antimicrobial resistance across the environment and to reduce the incidence of healthcare-associated infections.
Small RNAs that are highly conserved across many plant species are involved in stress responses. Plants are exposed to many types of unfavorable conditions during their life cycle that result in some degree of stress. Recent studies on microRNAs (miRNAs) have highlighted their great potential as regulators of stress tolerance in plants. One of the possible ways in which plants counter environmental stresses is by altering their gene expression by the action of miRNAs. miRNAs regulate the expression of target genes by hybridizing to their nascent reverse complementary sequences marking them for cleavage in the nucleus or translational repression in the cytoplasm. Some miRNAs have been reported to be key regulators in biotic as well as abiotic stress responses across many species. The present review highlights some of the regulatory roles of orthologous plant miRNAs in response to various types of stress conditions.
Objective
The screening of traditional fermented products is essential for the assessment of safety, security and further development of functional foods for the well-being of human health. The aim of the present study was to isolate and identify bacteria from fermented raw milk samples that exhibit health benefit upon consumption.
Method
In order to confirm the isolates as probiotics, several in-vitro assays were conducted to assess the probiotic properties of isolated bacteria. The initial screening includes tolerance to acid, bile, pancreatin and NaCl. The cell surface properties demonstrate their interaction with mucosal epithelium, which includes hydrophobicity and auto-aggregation assay. Safety assessment was done by performing hemolytic test and antibiotic susceptibility test. The antagonistic activity of probiotic strain was further evaluated against some pathogenic bacteria.
Results
Lactobacillus plantarum isolated from fermented raw milk was preliminarily identified by biochemical tests and further confirmed using 16S rRNA identification. The isolate designated as L. plantarum strain GCC_19M1, demonstrated significant tolerance to low pH, 0.3 % bile, 0.5 % pancreatin and 5 % NaCl. In the presence of simulated gastric juice (at pH 3), the isolate exhibited a survival rate of 93.48 to 96.97 %. Further, the development of ecological niches in the human gut and their successful accumulation has been revealed by auto-aggregation and hydrophobicity properties. Absence of hemolytic activity ensures the non-virulent nature of the strain. L. plantarum strain GCC_19M1 showed susceptibility towards towards gentamicin, tetracycline, kanamycin, meropenem and ceftriaxone, and exhibited an antagonistic effect on pathogenic bacteria.
Conclusion
The obtained results conveyed that L. plantarum strain GCC_19M1 has strong probiotic potential, and its presence in the fermented raw milk products may serve as a potent functional probiotic food.
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