Antibiofilm activity of symbiotic Bacillus species associated with marine gastropods

Abstract

Purpose: Generally, symbiotic marine bacteria are renowned for the synthesis of compounds with bioactive properties, and this has been documented in many previous studies. Therefore, the present study was aimed to isolate novel bacterial symbionts of gastropods that have the ability to synthesize bioactive compounds. These bioactive compounds could be used effectively as antibiofilm agents in order to overcome the problems associated with biofilm. Methods: The bacteria associated with the surface of marine gastropods were isolated and characterized. Following this, the bacterial metabolites were extracted and their antibiofilm effect was evaluated on biofilm-forming bacteria on artificial substrates. Moreover, the biofilm-forming bacterium Alteromonas sp. was treated with the extracts of symbiotic bacteria in order to evaluate the influence of extracts over the synthesis of extracellular polymeric substance (EPS). Besides, the biologically active chemical constituents of the extracts were separated using thin-layer chromatography and subjected to gas chromatography and mass spectrometry (GC-MS) analysis for characterization. Results: Three bacterial strains belonging to the species Bacillus firmus, Bacillus cereus and Bacillus subtilis were identified from the bacterial community associated with the gastropods. The antibiofilm assays revealed that the extract of three symbiotic bacteria significantly (p < 0.05) reduced the biofilm formation by the marine bacterium Alteromonas sp. on artificial materials. Also, the EPS synthesis by Alteromonas sp. was significantly inhibited due to symbiotic bacterial extract treatment. The chemical composition of the bioactive fraction isolated from the symbiotic bacteria extract revealed that most of the detected compounds were belonging to aromatic acid, fatty acid and carboxylic acid. Conclusion: The results of this study clearly revealed that the bacteria belonging to the above listed Bacillus species can be considered as a promising source of natural antibiofilm agents.

Bioprospecting the Antibiofilm and Antimicrobial Activity of Soil and Insect Gut Bacteria

“…Moreover, bacterial extracts from Streptomyces chrestomyceticus showed antimicrobial activity against Candida biofilms in concentrations ranging from 4 to 250 µg mL −1 [ 35 ], and extracts from three different species of Bacillus were able to inhibit Alteromonas sp. biofilms [ 36 ]. In this work, the antibiofilm activity of thirteen extracts from soil bacteria and insect gut bacteria is reported.…”

The anti-settlement activity of extracts of marine bacteria associated with soft corals against barnacle larvae

“…The Bacillus species used in this study and their accession number was provided in Table 1. The extraction process was carried out as previously described with some modifications (Viju et al, 2017;Viju et al, 2020). Briefly, 5ml aliquot of an overnight culture at an optical density of 0.2 at 600 nm (OD 600 ) was inoculated in a 500 ml flask containing marine nutrient broth (MNB) at half its capacity.…”

Natural Products and Pharmacological Properties of Symbiotic Bacillota (Firmicutes) of Marine Macroalgae

“…Another example is Taxol, previously obtained from a terrestrial plant, the Pacific yew [16], which was found afterwards to be a product of an endophytic fungus of the plant. Another reason to pursue symbiotic marine microorganisms is their ability to produce a greater variety of novel secondary metabolites than their free-living counterparts [17].…”