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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Mora-Ruiz, M. D., Font-Verdera, F., Diaz-Gil, C., Urdiain, M., Rodriguez-Valdecantos, G., Gonzalez, B., et al. (2015). Moderate halophilic bacteria colonizing the phylloplane of halophytes of the subfamily Salicornioideae (Amaranthaceae). Syst. Appl. Microbiol., 38(6), 406–416.
Abstract: Halophytes accumulate large amounts of salt in their tissues, and thus are susceptible to colonization by halotolerant and halophilic microorganisms that might be relevant for the growth and development of the plant. Here, the study of 814 cultured strains and 14,189 sequences obtained by 454 pyrosequencing were combined in order to evaluate the presence, abundance and diversity of halophilic, endophytic and epiphytic microorganisms in the phytosphere of leaves of members of the subfamily Salicornioideae from five locations in Spain and Chile. Cultures were screened by the tandem approach of MALDI-TOF/MS and 16S rRNA gene sequencing. In addition, differential centrifugation was used to enrich endophytes for further DNA isolation, 16S rRNA gene amplification and 454 pyrosequencing. Culturable and non-culturable data showed strong agreement with a predominance of Proteobacteria, Firmicutes and Actinobacteria. The most abundant isolates corresponded to close relatives of the species Chromohalobacter canadensis and Salinicola halophilus that comprised nearly 60% of all isolates and were present in all plants. Up to 66% of the diversity retrieved by pyrosequencing could be brought into pure cultures and the community structures were highly dependent on the compartment where the microorganisms thrived (plant surface or internal tissues). (C) 2015 Elsevier GmbH. All rights reserved.
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