title: Bioactive stilbenes from a Bacillus sp. N strain associated with a novel rhabditid entomopathogenic nematode.
abstract: OBJECTIVE
  The aim of the present study was to purify and characterize a natural antimicrobial compound from Bacillus sp. strain N associated with a novel rhabditid entomopathogenic nematode.
  
  
  RESULTS
  The cell-free culture filtrate of a bacterium associated with a novel entomopathogenic nematode (EPN), Rhabditis (Oscheius) sp. exhibited strong antimicrobial activity. The ethyl acetate extract of the bacterial culture filtrate was purified by column chromatography, and two bioactive compounds were isolated and their chemical structures were established based on spectral analysis. The compounds were identified as 3,4',5-trihydroxystilbene (1) and 3,5-dihydroxy-4-isopropylstilbene (2). The presence of 3,4',5-trihydroxystilbene (resveratrol) is reported for the first time in bacteria. Compound 1 showed antibacterial activity against all the four test bacteria, whereas compound 2 was effective against the Gram-positive bacteria only. Compounds 1 and 2 were active against all the five fungi tested and are more effective than bavistin, the standard fungicide. The antifungal activity of the compounds against the plant pathogenic fungi, Rhizoctonia solani is reported for the first time.
  
  
  CONCLUSIONS
  Cell-free extract of the bacterium and isolated stilbenes demonstrated high antibacterial activity against bacteria and fungi especially against plant pathogenic fungi. We conclude that the bacterium-associated EPN are promising sources of natural bioactive secondary metabolites.
  
  
  CONCLUSIONS
  Stilbene compounds can be used for the control of fungi and bacteria.
authors.affiliation: Division of Crop Protection/Division of Crop Utilisation, Central Tuber Crops Research Institute, Thiruvananthapuram, Kerala, India.
authors.forename: S N
authors.initials: SN
authors.lastname: Kumar
authors.forename: J V
authors.initials: JV
authors.lastname: Siji
authors.forename: K N
authors.initials: KN
authors.lastname: Rajasekharan
authors.forename: B
authors.initials: B
authors.lastname: Nambisan
authors.forename: C
authors.initials: C
authors.lastname: Mohandas
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000378:metabolism* / Q000494:pharmacology; D001407:Bacillus / Q000378:metabolism*; D001688:Biological Products / Q000378:metabolism / Q000494:pharmacology; D009348:Nematoda / Q000378:metabolism / Q000382:microbiology*; D000077185:Resveratrol; D013267:Stilbenes / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D001688:Biological Products; D013267:Stilbenes; D000077185:Resveratrol