bacillomycin-d and surfactin-peptide

Topics: Aeromonas hydrophila; Animals; Antibiosis; Antimicrobial Cationic Peptides; Bacillus; Bacteriocins; Biological Control Agents; Carps; Fish Diseases; Lipopeptides; Peptides, Cyclic; Probiotics; Whole Genome Sequencing

In the current study, the biocontrol potential of a novel strain Bacillus sp. PPM3 isolated from marine sediment from the Red Sea in Hurghada, Egypt is recognized. This novel strain was selected out of 32 isolates based on its ability to suppress the growth of four plant pathogenic fungi: Aspergillus flavus, Fusarium graminearum, Mucor sp. and Alternaria sp. The new marine strain was identified and characterized by phenotypic and molecular approaches. The culture filtrate of Bacillus sp. PPM3 suppressed the growth and spore germination of all tested fungi in vitro with the highest value of inhibition reported for Mucor sp. (97.5%). The antifungal effect of the culture filtrate from the strain PPM3 was due to production of highly stable secondary metabolites resistant to extreme pH, temperature and enzymatic treatments. A PCR analysis confirmed the expression of genes involved in the synthesis of antifungal lipopeptides: iturin, bacillomycin D, mycosubtilin and surfactin. In a greenhouse experiment strain PPM3 effectively reduced disease incidence of F. graminearum in maize plants and displayed additional plant growth stimulating effect. The results show that novel marine strain PPM3 could have a potential in commercial application as biocontrol agent for treatment of various plant diseases caused by soil-borne and postharvest pathogenic fungi.

Topics: Alternaria; Antifungal Agents; Antimicrobial Cationic Peptides; Aspergillus flavus; Bacillus; Biological Control Agents; DNA, Bacterial; Egypt; Fungi; Fusarium; Geologic Sediments; Hydrogen-Ion Concentration; Indian Ocean; Lipopeptides; Lipoproteins; Mucor; Peptides; Peptides, Cyclic; Plant Development; Plant Diseases; RNA, Ribosomal, 16S; Secondary Metabolism; Seedlings; Species Specificity; Spores, Fungal; Temperature; Zea mays

Marine biofilms are a virtually untapped source of bioactive molecules that may find application as novel antifoulants in the marine paint industry. This study aimed at determining the potential of marine biofilm bacteria to produce novel biomolecules with potential application as natural antifoulants. Nine representative strains were isolated from a range of surfaces and were grown in YEB medium and harvested during the late exponential growth phase. Bacterial biomass and spent culture medium were extracted with ethanol and ethyl acetate, respectively. Extracts were assayed for their antifouling activity using two tests: (1) antimicrobial well diffusion test against a common fouling bacterium, Halomonas marina, and (2) anti-crustacean activity test using Artemia salina. Our results showed that none of the ethanolic extracts (bacterial biomass) were active in either test. In contrast, most of the organic extracts had antimicrobial activity (88%) and were toxic towards A. salina (67%). Sequencing of full 16 S ribosomal DNA analysis showed that the isolates were related to Bacillus mojavensis and Bacillus firmus. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF-MS) profiling of ethyl acetate extracts of culture supernatants showed that these species produce the bioactive lipopeptides surfactin A, mycosubtilin and bacillomycin D.

Topics: Animals; Anti-Bacterial Agents; Antimicrobial Cationic Peptides; Artemia; Bacillus; Biofilms; Calcium Carbonate; Halomonas; Hydrocharitaceae; Lipopeptides; Lipoproteins; Molecular Sequence Data; Peptides; Peptides, Cyclic; Phylogeny; Plant Leaves; Seawater; Sequence Analysis, DNA; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization