Isolation and Characterization of a Novel Actinomycete Isolated from Marine Sediments and Its Antibacterial Activity against Fish Pathogens

Abstract

Marine habitats are especially complex, with a varied diversity of living organisms. Marine organisms, while living in such intense conditions, have developed great physiological and metabolic potential to survive. This has led them to produce several potent metabolites, which their terrestrial counterparts are unable to produce. Over the past few years, marine Actinomycetes have been considered one of the most abundant sources of diverse and novel metabolites. In this work, an attempt was made to isolate Actinomycetes from marine sediments in terms of their ability to produce several novel bioactive compounds. A total of 16 different Actinomycete colonies were obtained from marine sediment samples. Among the 16 Actinomycete isolates, 2 isolates demonstrated in vitro antibacterial activity against Aeromonas hydrophila and Vibrio parahemolyticus. However, among them, only one isolate was found to have potent antibacterial activity, and hence, was taken for further analysis. This isolate was designated as Beijerinickia fluminensis VIT01. The bioactive components obtained were extracted and later subjected to Fourier transform infrared spectroscopy (FTIR) and gas chromatography–mass spectroscopy (GC-MS) analyses for identification. Several novel bioactive compounds were reported from the data obtained and were found to have potent antibacterial activity. Hence, they could be used as an alternative to antibiotics for treating several fish pathogens in the aquaculture industry.

Identification of Antimicrobial Metabolites from the Egyptian Soil-Derived Amycolatopsis keratiniphila Revealed by Untargeted Metabolomics and Molecular Docking

“…Actinomycetes are among the richest providers of secondary metabolites and produce potent bioactive metabolites [ 56 ]. The genus Amycolatopsis is a significant supplier of many antibiotics and other useful bioactive natural products.…”

“…The genus Amycolatopsis is a significant supplier of many antibiotics and other useful bioactive natural products. Rifamycin and vancomycin are the two most well-known antibiotics Amycolatopsis strains produce [ 10 , 56 ]. Recent years have seen a surge in interest in the OSMAC strategy.…”

Biodiversity and biological applications of marine actinomycetes—Abu-Qir Bay, Mediterranean Sea, Egypt

“…The standard inoculum of the actinomycetes under test was streaked over the surface of the agar plates, incubated at 35 ± 2 °C for 7 days and pH 7. At the end of the incubation period, the growth was recorded visually by the presence of substrate and aerial mycelia [ 9 , 10 ].…”

“…The highest concentration of salt that allowed growth was recorded. There was no clear-cut borderline between growth and no growth since in most cases growth was retarded and or less dense in the form of smaller colonies, with higher salt concentrations tolerated as compared with the control [ 9 , 10 ].…”

Napyradiomycin B4 Suppresses RANKL-Induced Osteoclastogenesis and Prevents Alveolar Bone Destruction in Experimental Periodontitis

“…Marine-derived actinomycetes have gained attention as a reservoir of bioactive compounds that exhibit various biological properties relevant to human health, and many novel products with anticancer, antibacterial, and antimalarial functions have been isolated and characterized. − Napyradiomycins are meroterpenoid natural products mainly produced by marine-derived actinomycetes, and their cytotoxic, antimicrobial, antioxidant, anti-inflammatory, and ATPase inhibitory activities have been reported. − The chemical structures of napyradiomycins are divided into three classes by the types of C-10a-attached side chain: Class A possessed a linear side chain; Class B consisted with the cyclized side chain to the formation of a cyclohexane ring; and Class C showed a 14-membered ring formation of side chains by cyclization between C7 and C10a. Recently, the ability of several napyradiomycin derivatives, including napyradiomycin B4, to activate nuclear factor-erythroid 2-related factor 2 (Nrf2) was demonstrated, and the ablation of Nrf2 enhances RANKL-mediated osteoclastogenesis and osteoclastic bone resorption, indicating a negative regulation of osteoclast differentiation by Nrf2. , …”