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Gnanasekaran, C., Govindan, R., Chelliah, C. K., Govindan, R., Ranganathan, P., Muthuchamy, M., et al. (2023). Isolation and molecular detection of endophytic actinomycetes Nocardiopsis dassonvillei DMS 1 (MH900216) from marine sea grasses with bacterial inactivation. Biocatal. Agric. Biotechnol., 54, 102938.
Abstract: In recent years, new antibiotics have been discovered around the world in order to inhibit multi drug resistant (MDR) pathogens. To overcome this problem, marine actinomycetes are an alternative choice for producing new bioactive compounds that inhibit MDR bacteria. The typical endophytic actinomycete (EA) Nocardiopsis dassonvillei (N. dassonvillei) DMS 1 (MH900216) was isolated from marine Sea grasses by surface sterilization method. After surface sterilization, it was confirmed that the pure, dry, white-colored spore producing colonies emerged from the internal tissue of the Sea grasses. The crude extract of N. dassonvillei DMS 1 (MH900216) demonstrated 8 and 10-mm zones of inhibition against A. baumannii and K. pneumoniae, respectively. The composition of N. dassonvillei DMS 1 (MH900216) with potential anti-bacterial properties was studied by GC-MS analysis and exhibited 22 chemical compounds. Subsequently, the molecular identification and phylogenetic construction of the isolated EA strain was confirmed as N. dassonvillei DMS 1 (MH900216). The liquid-liquid extraction of the compound demonstrated 24-and 26-mm zones of inhibition against A. baumannii and K. pneumoniae, respectively. Furthermore, the purified crude compound demonstrated 92% and 94% cell death against A. baumannii and K. pneumoniae, respectively, at a minimum inhibitory concentration of 500 mu g/mL. Overall, the present study demonstrated the antibacterial properties of the EA N. dassonvillei DMS 1 (MH900216) isolated from Sea grasses and their importance as alternative sources for discovering new antibiotics to inhibit MDR bacteria.
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Govindan, R., Gnanasekaran, C., Govindan, R., Muthuchamy, M., Quero, F., Jothi, A., et al. (2023). Anti-quorum Sensing and Anti-biofilm Effect of Nocardiopsis synnemataformans RMN 4 (MN061002) Compound 2,6-Di-tert-butyl, 1,4-Benzoquinone Against Biofilm-Producing Bacteria. Appl. Biochem. Biotechnol., Early Access.
Abstract: In this study, the anti-biofilm compound of 2,6-Di-tert-butyl, 1,4-benzoquinone was purified from Nocardiopsis synnemataformans (N. synnemataformans) RMN 4 (MN061002). To confirm the compound, various spectroscopy analyses were done including ultraviolet (UV) spectrometer, Fourier transform infrared spectroscopy (FTIR), analytical high-performance liquid chromatography (HPLC), preparative HPLC, gas chromatography-mass spectroscopy (GC-MS), liquid chromatography-mass spectroscopy (LC-MS), and 2D nuclear magnetic resonance (NMR). Furthermore, the purified compound was shown 94% inhibition against biofilm-producing Proteus mirabilis (P. mirabilis) (MN396686) at 70 mu g/mL concentrations. Furthermore, the metabolic activity, exopolysaccharide damage, and hydrophobicity degradation results of identified compound exhibited excellent inhibition at 100 mu g/mL concentration. Furthermore, the confocal laser scanning electron microscope (CLSM) and scanning electron microscope (SEM) results were shown with intracellular damages and architectural changes in bacteria. Consecutively, the in vivo toxicity effect of the compound against Artemia franciscana (A. franciscana) was shown to have a low mortality rate at 100 mu g/mL. Finally, the molecular docking interaction between the quorum sensing (QS) genes and identified compound clearly suggested that the identified compound 2,6-Di-tert-butyl, 1,4-benzoquinone has anti-quorum sensing and anti-biofilm activities against P. mirabilis (MN396686).
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