Isolation of proline-based cyclic dipeptides from Bacillus sp. N strain associated with rhabitid entomopathogenic nematode and its antimicrobial properties
- 1.2k Downloads
Entomopathogenic nematodes (EPN) are well-known as biological control agents and are found to have associated bacteria which can produce a wide range of bioactive secondary metabolites. We report herewith isolation of six proline containing cyclic dipeptides cyclo(d-Pro-l-Leu), cyclo(l-Pro-l-Met), cyclo(d-Pro-l-Phe), cyclo(l-Pro-l-Phe), cyclo(l-Pro-l-Tyr) and cyclo(l-Pro-d-Tyr) from ethyl acetate extract of the Luria Broth (LB) cell free culture filtrate of Bacillus sp. strain N associated with a new EPN Rhabditis sp. from sweet potato weevil grubs collected from Central Tuber Crops Research Institute farm. Antimicrobial studies of these 2,5-diketopiperazines (DKPs) against both medicinally and agriculturally important bacterium and fungi showed potent inhibitory values in the range of μg/mL. Cyclic dipeptides showed significantly higher activity than the commercial fungicide bavistin against agriculturally important fungi, viz., Fusarium oxysporum, Rhizoctonia solani, and Pencillium expansum. The highest activity of 2 μg/mL by cyclo(l-Pro-l-Phe) was recorded against P. expansum, a plant pathogen responsible for causing post harvest decay of stored apples and oranges. To our knowledge, this is the first report on the isolation of these DKPs from Rhabditis EPN bacterial strain Bacillus sp.
KeywordsEntomopathogenic nematodes Cyclic dipeptides Minimum inhibitory concentration Antimicrobial activity
We are grateful to Dr. R. Srinivas, HOD, NCMS, IICT, Hyderabad for HRMS analysis. This work was funded by Indian council of Medical Research (ICMR).
- Akhurst RJ (1982) Antibiotic activity of Xenorhabdus spp., bacteria symbiotically associated with insect pathogenic nematodes of the families Hettrorhabditidae and Steinernematidae. J Gen Microbiol 128:3061–3065Google Scholar
- CLSI, Clinical and Laboratory Standards Institute (2006) Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically. CLSI documents M27-S3, WayneGoogle Scholar
- CLSI, Clinical and Laboratory Standards Institute (2008) Reference methods for broth dilution antifungal susceptibility tests of yeasts. CLSI documents M27-S3, WayneGoogle Scholar
- Deepa I, Mohandas C, Makesh KT, Siji JV, Prakash KBS, Babu B (2010) Identification of new entomopathogenic nematodes (EPNs) based on sequences of D2–D3 expansion fragments of the 28SrRNA. J Root Crops 36(2):227–232Google Scholar
- Gaugler R, Kaya HK (1990) Entomopathogenic nematodes in biological control. CRC Press, Boca Raton, pp 75–90Google Scholar
- Holden MTG, Chhabra SR, de Nys R, Stead P, Bainton NJ, Hill PJ, Manefield M, Kumar N, Labatte M, England D, Rice S, Givskov M, Salmond GPC, Stewartm GSAB, Bycroft BW, Kjelleberg SA, Williams P (1999) Quorum-sensing cross talk: isolation and chemical characterization of cyclic dipeptides from Pseudomonas aeruginosa and other gram negative bacteria. Mol Microbiol 33:1254CrossRefGoogle Scholar
- Rollas S, Kalyoncuoglu N, Sur-Altiner D, Yegenglu Y (1993) 5-(4-Aminophenyl)-4-substituted 2,4-dihydro-3H-1,2,4-triazole-3-thiones: synthesis, antibacterial and antifungal activities. Pharmazie 48:308–309Google Scholar
- Thaler JO, Duvic B, Givaudan A, Boemare N (1998) Isolation and entomotoxic properties of the Xenorhabdus nematophilus F1 lecithinase. Appl Environ Microbiol 64:2367–2373Google Scholar
- Wang Y, Fang X, Cheng Y, Zhang X (2011) Manipulation of pH shift to enhance the growth and antibiotic activity of Xenorhabdus nematophila. J Biomed Biotechnol 2011:1–9Google Scholar