Premsagar Korripally

Salt-tolerant plant growth-promoting (PGP) actinobacteria play an important role in enhancing plant tolerance to salinity stress and improving crop productivity. Here, 9 morphologically distinct actinobacterial isolates (A-I) were isolated from the rhizosphere soil of Oryza sativa cultivated in the Nalgonda district, Telangana, screened for PGP characteristics (nitrogen fixation, indole-3-acetic acid production (IAA), and phosphate solubilisation) and salt tolerance. Among them, isolate H exhibited superior PGP activity and salt tolerance, growing in media containing up to 10% NaCl. Hence, it was selected for further work. Isolate H produced cellulase, lipase, amylase and showed a positive catalase reaction. It utilised glucose, fructose, galactose, and sucrose, but not maltose. Antibiotic susceptibility analysis indicated that isolate H was partially resistant to penicillin but sensitive to tetracycline, ciprofloxacin, and vancomycin. Molecular identification based on 16S rDNA sequencing (1,356 bp) revealed that isolate H shared 99.78% sequence similarity and 99% query coverage with Streptomyces levis NBRC 15423(T), suggesting that the isolate belongs to the genus Streptomyces. Seed germination efficiency (%) revealed that the 24 hrs culture (T1) of isolate H had a significantly greater effect on rice seed germination than the 48 hrs culture (T2). The germination rate of rice seeds in T1 was 86.67%, followed by T2 (72.00%), the control (62.33%), and distilled water (55.67%), indicating that the 24 hrs grown culture of isolate H may be used to enhance rice seed germination under salt stress. This study provides preliminary evidence of the potential of a Streptomyces levis strain as a PGP bacterium under saline conditions.

Nine actinobacterial isolates were purified from the sediment sample of Kogilvai village, Warangal, Telangana, based on their capability to grow on the minimal medium with Ferulic acid (FA) as only Carbon (C) source. FA to Vanillin conversion capacity of these isolates was identified by Thin-layer chromatography (TLC). Biotransformation of FA to Vanillin was high by four isolates, S1, S3, O3 and O4 when compared to other five isolates (O1, O2, S2, S4 and S5) with initial pH 7 in basal medium. Among these four isolates, optimal and rapid FA to Vanillin bioconversion of 140 mg/L was shown by isolate S1 with UV-spectrophotometry. Its conversion was confirmed by High Performance Liquid Chromatography (HPLC) analysis with retention time of 2.9 min after 28hrs of incubation at 37°C with 1g/L ferulic acid in the medium with 150 rpm. Isolate S1 could utilize Lactose, Maltose, Glycerol, Fructose, Galactose, Sucrose, Dextrose, L-Arabinose, ONPG, Esculin and not other carbohydrates present in the Himedia Hicarbo kit. Molecular characterization showed that 16S rDNA gene sequence of isolate S1 was 98.27% similar to Limosilactobacillus fermentum CECT 562 with completeness of 96.7% and was identified as Limosilactobacillus sp. 16S rDNA gene sequence of isolate S1 was submitted to NCBI GenBank and its accession number was OR136396. As this isolate has high potential of FA to Vanillin biotransformation capacity, it can be further explored to be used for industrial setups for commercial exploitation.

In an attempt to synthesize new chemical entities with promising biological activity, a set of six novel pyrimidinedione analogues 6(a-f) was prepared. The compound 4 was coupled with different amines by using HBTU as a coupling reagent. The derivatives were characterized by ¹HNMR,¹³CNMR and HRMS. The analogues were evaluated for their antibacterial and antioxidant activity. The DPPH and ABTS methods were used to test the antioxidant activity of the moieties. Among the six pyrimidinedione analogues, 6b, 6d, and 6f exhibited significant antioxidant effects. The paper disc diffusion method was adopted to evaluate the antibacterial activity of the samples. The analogues 6b, 6c and 6e exhibited potency against gram-negative and gram-positive pathogens. Further, to evaluate the binding abilities of the analogues to the protein active sites, molecular docking studies were performed. The results of the docking studies were found to be consistent with the antibacterial potential of the analogues. The efficacy of these analogues provides insight into their use as novel antioxidant and antibacterial agents.

The diets of two-thirds of the world’s population are deficient in one or more essential elements and one of the approaches to enhance the levels of mineral elements in food crops is by developing plants with ability to accumulate them in edible parts. Besides conventional methods, transgenic technology can be used for enhancing metal acquisition in plants. Copper is an essential element, which is often deficient in human diet. With the objective of developing plants with improved copper acquisition, a high-affinity copper transporter gene (tcu-1) was cloned from fungus Neurospora crassa and introduced into a model plant (Nicotiana tabacum). Integration of the transgene was confirmed by Southern blot hybridization. Transgenic tobacco plants (T₀ and T₁) expressing tcu-1, when grown in hydroponic medium spiked with different concentrations of copper, showed higher acquisition of copper (up to 3.1 times) compared with control plants. Transgenic plants grown in soil spiked with copper could also take up more copper compared with wild-type plants. Supplementation of other divalent cations such as Cd²⁺ and Zn²⁺ did not alter uptake of Cu by transgenic plants. The present study has shown that expression of a heterologous copper transporter in tobacco could enhance acquisition of copper.