Abstract
Many members of the Halobacteriaceae were found to produce halocins, molecules that inhibit the growth of other halophilic archaea. Halocin H4 that is produced by Haloferax mediterranei and inhibits the growth of Halobacterium salinarum is one of the best studied halocins to date. The gene encoding this halocin had been previously identified as halH4, located on one of Hfx. mediterranei megaplasmids. We generated a mutant of the halH4 gene and examined the killing ability of the Haloferax mediterranei halH4 mutant with respect to both Halobacterium salinarum and Haloferax volcanii. We showed that both wild-type Hfx. mediterranei and the halH4 mutant strain efficiently inhibited the growth of both species, indicating halocin redundancy. Surprisingly, the halH4 deletion mutant exhibited faster growth in standard medium than the wild type, and is likely to have a better response to several nucleotides, which could explain this phenotype.
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Acknowledgments
The authors would like to thank Jerry Eichler for providing Hbt. salinarum strain and Neta Altman-Price for helpful advice and discussion. This research was supported by THE ISRAEL SCIENCE FOUNDATION (Grant No. 201/12).
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Communicated by A. Oren.
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792_2013_579_MOESM1_ESM.tif
Fig. S1 Cell survival before and after interspecies mating, measured by CFU (colony forming unites). Based on 4 biological repeats, error bars indicate SEM. (TIFF 31 kb)
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Fig. S2 Growth curve analysis of Hfx. mediterranei W.T (WR505), Hfx. mediterranei ΔpyrE (WR510) and Hfx. mediterranei WR510 ΔhalH4 on YPC medium compared to strain WR505 on YPC medium supplemented with nucleic acids. Based on 3 biological repeats, representative results are shown. (TIFF 182 kb)
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Naor, A., Yair, Y. & Gophna, U. A halocin-H4 mutant Haloferax mediterranei strain retains the ability to inhibit growth of other halophilic archaea. Extremophiles 17, 973–979 (2013). https://doi.org/10.1007/s00792-013-0579-8
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DOI: https://doi.org/10.1007/s00792-013-0579-8