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Mar Drugs. 2018 May 24;16(6). pii: E180. doi: 10.3390/md16060180.

A Marine Isolate of Bacillus pumilus Secretes a Pumilacidin Active against Staphylococcus aureus.

Author information

1
Department of Biology, Federico II University of Naples, 80126 Naples, Italy. ornellasaggese2010@libero.it.
2
Department of Biology, Federico II University of Naples, 80126 Naples, Italy. rosanna.culurciello@gmail.com.
3
Department of Chemical Sciences, Federico II University of Naples, 80126 Naples, Italy. angela.casillo@unina.it.
4
Department of Chemical Sciences, Federico II University of Naples, 80126 Naples, Italy. mariamichela.corsaro@unina.it.
5
Department of Biology, Federico II University of Naples, 80126 Naples, Italy. ericca@unina.it.
6
Department of Biology, Federico II University of Naples, 80126 Naples, Italy. lorbacci@unina.it.

Abstract

Producing antimicrobials is a common adaptive behavior shared by many microorganisms, including marine bacteria. We report that SF214, a marine-isolated strain of Bacillus pumilus, produces at least two different molecules with antibacterial activity: a molecule smaller than 3 kDa active against Staphylococcus aureus and a molecule larger than 10 kDa active against Listeria monocytogenes. We focused our attention on the anti-Staphylococcus molecule and found that it was active at a wide range of pH conditions and that its secretion was dependent on the growth phase, medium, and temperature. A mass spectrometry analysis of the size-fractionated supernatant of SF214 identified the small anti-Staphylococcus molecule as a pumilacidin, a nonribosomally synthesized biosurfactant composed of a mixture of cyclic heptapeptides linked to fatty acids of variable length. The analysis of the SF214 genome revealed the presence of a gene cluster similar to the srfA-sfp locus encoding the multimodular, nonribosomal peptide synthases found in other surfactant-producing bacilli. However, the srfA-sfp cluster of SF214 differed from that present in other surfactant-producing strains of B. pumilus by the presence of an insertion element previously found only in strains of B. safensis.

KEYWORDS:

B. pumilus; SF214; antimicrobials; lipopeptides; pumilacidin; surfactants; surfactin

PMID:
29882934
PMCID:
PMC6025400
DOI:
10.3390/md16060180
[Indexed for MEDLINE]
Free PMC Article

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