Purification and genetic characterization of gassericin E, a novel co-culture inducible bacteriocin from Lactobacillus gasseri EV1461 isolated from the vagina of a healthy womanReportar como inadecuado

Purification and genetic characterization of gassericin E, a novel co-culture inducible bacteriocin from Lactobacillus gasseri EV1461 isolated from the vagina of a healthy woman - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

BMC Microbiology

, 16:37

Applied microbiology


BackgroundLactobacillus gasseri is one of the dominant Lactobacillus species in the vaginal ecosystem. Some strains of this species have a high potential for being used as probiotics in order to maintain vaginal homeostasis, since they may confer colonization resistance against pathogens in the vagina by direct inhibition through production of antimicrobial compounds, as bacteriocins. In this work we have studied bacteriocin production of gassericin E GasE, a novel bacteriocin produced by L. gasseri EV1461, a strain isolated from the vagina of a healthy woman, and whose production was shown to be promoted by the presence of certain specific bacteria in co-culture. Biochemical and genetic characterization of this novel bacteriocin are addressed.

ResultsWe found that the inhibitory spectrum of L. gasseri EV1461 was broad, being directed to species both related and non-related to the producing strain. Interestingly, L. gasseri EV1461 inhibited the grown of pathogens usually associated with bacterial vaginosis BV. The antimicrobial activity was due to the production of a novel bacteriocin, gassericin E GasE. Production of this bacteriocin in broth medium only was achieved at high cell densities. At low cell densities, bacteriocin production ceased and only was restored after the addition of a supernatant from a previous bacteriocin-producing EV1461 culture autoinduction, or through co-cultivation with several other Gram-positive strains inducing bacteria. DNA sequence of the GasE locus revealed the presence of two putative operons which could be involved in biosynthesis and immunity of this bacteriocin gaeAXI, and in regulation, transport and processing gaePKRTC. The gaePKR encodes a putative three-component regulatory system, involving an autoinducer peptide GaeP, a histidine protein kinase GaeK and a response regulator GaeR, while the gaeTC encodes for an ABC transporter GaeT and their accessory protein GaeC, involved in transport and processing of the bacteriocin. The gaeAXI, encodes for the bacteriocin gassericin E GasE, a putative peptide bacteriocin GaeX, and their immunity protein GaeI.

ConclusionsThe origin of the strain vagina of healthy woman and its ability to produce bacteriocins with inhibitory activity against vaginal pathogens may be an advantage for using L. gasseri EV1461 as a probiotic strain to fight and-or prevent bacterial infections as bacterial vaginosis BV, since it could be better adapted to live and compete into the vaginal environment.

KeywordsBacteriocin Quorum sensing Gassericin Three-component regulatory system AbbreviationsBVbacterial vaginosis

GasEgassericin E

CFSscell-free supernatants

PCRpolymerase chain reaction

BHIbrain heart Infusion

TSBtryptic soy broth agar

RCAreinforced clostridial agar broth medium

ETSAenriched tryptic soy agar

RPC-FPLCreverse-phase chromatography-fast protein liquid chromatography

SDS-PAGEsodium dodecyl sulfate polyacrylamide gel electrophoresis

MALDI-TOF-MSmatrix-assisted laser desorption-ionization time of flight mass spectrometry

dNTPsdeoxynucleotides triphosphates

BLASTbasic local alignment search tool


CFUcolony forming units

BUbacteriocin units

ORFsopen reading frames

AIPautoinducer peptide

HPKhistidine protein kinases

RRresponse regulator

TCRSthree-component regulatory system

BVABbacterial vaginosis associated bacteria

Electronic supplementary materialThe online version of this article doi:10.1186-s12866-016-0663-1 contains supplementary material, which is available to authorized users.

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Autor: Antonio Maldonado-Barragán - Belén Caballero-Guerrero - Virginia Martín - José Luis Ruiz-Barba - Juan Miguel Rodríguez

Fuente: https://link.springer.com/

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