Research Article LC-MS based identification of secondary metabolites from marine antagonistic endophytic bacteria

Abstract

Halophytes occupy coastal and sub-coastal area of marine environment. They potential candidates for search of novel and new bacterial flora that have immense potential to yield novel therapeutic agents. Six different endophytic bacteria have been isolated from pneumatophores and roots of three halophytes (Salsola imbricata, Avicennia marina and Haplopeplis perfoliata) collected from western coastal area of Jeddah, Saudi Arabia. After testing against five fungal pathogens all were active against oomycetes fungal pathogens, Phytophthora capsici and Pythium ultimum. Molecular identification of the bacteria was done on the basis of 16S rRNA gene sequences which revealed 95.9-99.4% sequence identity to related type strains and were placed in four major genera and two major classes: Actinobacteria (Streptomyces and Nocardioides) and α-Proteobacteria (Inquilinus and Labrezia). Active metabolites of these six bacterial endophytes including EA61, EA83, EA85, EA87, EA97 and EA220 were identified by subjecting to chemical analyses using liquid chromatography-mass spectrometry (LC-MS). LC-MS analyses showed presence of different active compounds in the culture extracts of these isolates. Some of these metabolites are already reported as synthetic molecules and has diverse biological functions as antimicrobial, anti-inflammatory and anthelmintic compounds such as such as Sulfamethoxypyridazine, Sulfamonomethoxine, Sulfamerazine and Dimetridazole, Sulfadiazin. Genetics and Molecular Research 17 (1): gmr16039857 Bibi F, et al. 2 Nalidixic acid and Oxibendazole. This study provides an insight into potential bacterial flora of halophytes producing bioactive metabolites of medical significance.

Effect of Marine Bacteria and Ulvan on the Activity of Antioxidant Defense Enzymes and the Bio-Protection of Papaya Fruit against Colletotrichum gloeosporioides

“…Antagonist bacteria are generally isolated from plants, fruit, or soil [9], but the isolation of antagonistic microorganisms in extreme environments has been studied little. Bibi et al [10,11] mentioned that bacteria isolated from marine environments play an important role in plant protection against phytopathogens because of their capacity to produce diverse antimicrobial substances and induce host resistance. Some reports have indicated the efficiency of bacteria, such as Stenotrophomonas rhizophila and Bacillus amyloliquefaciens, in the biocontrol of phytopathogen fungi in peach [12], mango [13], and apple [14] postharvest.…”

Isolation and Identification of Bioactive Compounds from Streptomyces actinomycinicus PJ85 and Their In Vitro Antimicrobial Activities against Methicillin-Resistant Staphylococcus aureus

“…Bibi et al (2017) reported the presence of different active compounds, including sulfamonomethoxine, sulfadiazine, ibuprofen, and metronidazole-OH, in culture extracts of Streptomyces sp. EA85 based on LC–MS analysis [ 60 ]. In this study, active compounds present in the ethyl acetate extract of Streptomyces sp.…”

Untangling Structural and Functional Diversity of Prokaryotic Microbial Assemblage on Mangrove Pneumatophores

“…Another batch of epiphytic bacterial species on the pneumatophores was isolated from the Ayiramthengu mangrove ecosystem in India, predominated by phosphatase-solubilizing bacterial strains (78% of the total bacterial isolates), and these isolates could also produce extracellular enzymes lipase (75%), cellulase (71%), and amylase (52%) [84]. Bibi et al [85] isolated and identified three different endophytic bacterial strains, Nocardioides aromaticivorans, Streptomyces spectabilis, and Nocardioides albus, on the pneumatophores of A. marina collected from the western coastal area of Jeddah, Saudi Arabia, and all had antipathogenic activity against plant pathogens Phytophthora capsici and Pythium ultimum. Other than these, no information is available on other functional attributes of pneumatophore bacteria.…”

“…For many years, the application of culture-dependent microbiological techniques has remained an extremely proficient and robust tool for the assessment of the taxonomic and functional diversity of microbes in various ecosystems. To date, most of the studies assessing the functions of mangrove microbial isolates, in particular pneumatophore-associated microbes, have relied on the isolation of microbial species in specific growth media and investigated plant growth-promoting traits, the production of antimicrobial enzymes, and secondary metabolites [42,76,85]. However, it is well accepted that only a few microorganisms can be cultured in a laboratory, as very little is known about the organism's natural environment, making it difficult to fully replicate it.…”

“…Our understanding of the diversity of enzymes and metabolites remains very limited, which poses challenges related to the annotation of identified compounds for reconstructing metabolic pathways and assessing microbial processes. So far, only one study has employed metabolomics to detect the presence of various active metabolites, including allopurinol, diazepam, dimetridazole, gemfibrozil, ibuprofen, metronidazole-oh, nalidixic acid, oxibendazole, sulfamonomethoxine, sulfadiazin, sulfacetamide, and sulfaethoxypyridazine, in culture extracts of bacterial isolates from pneumatophores of A. marina collected from the western coastal area of Jeddah, Saudi Arabia [85]. The application of metaproteomics to study biological processes occurring within the PAPM community is yet to be explored.…”