Genomic and Proteomic Characterization of Bacteriocin-ProducingLeuconostoc mesenteroidesStrains Isolated from Raw Camel Milk in Two Southwest Algerian Arid Zones

Information on the microbiology of camel milk is very limited. In this work, the genetic characterization and proteomic identification of 13 putative producing bacteriocinLeuconostocstrains exhibiting antilisterial activity and isolated from camel milk were performed. DNA sequencing of the 13 selected strains revealed high homology among the 16S rRNA genes for all strains. In addition, 99% homology withLeuconostoc mesenteroideswas observed when these sequences were analysed by the BLAST tool against other sequences from reference strains deposited in the Genbank. Furthermore, the isolates were characterized by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDITOF MS) which allowed for the identification of 2 mass peaks 6242 m/z and 5118 m/z that resulted to be specific to the speciesL. mesenteroides. Remarkably, the phyloproteomic tree provided more intraspecific information ofL. mesenteroidesthan phylogenetic analysis. Accordingly, phyloproteomic analysis groupedL. mesenteroidesstrains into different subbranches, while allL. mesenteroidesisolates were grouped in the same branch according to phylogenetic analysis. This study represents, to our knowledge, the first report on the use of MALDI-TOF MS on the identification of LAB isolated from camel milk.

Download Full-text

Phenotypic and molecular characterization of chickpea rhizobia isolated from different areas of Tunisia

Canadian Journal of Microbiology ◽

10.1139/w06-127 ◽

2007 ◽

Vol 53 (3) ◽

pp. 427-434 ◽

Cited By ~ 17

Author(s):

Boulbaba L’taief ◽

Bouaziz Sifi ◽

Maher Gtari ◽

Mainassara Zaman-Allah ◽

Mokhtar Lachaâl

Keyword(s):

Rflp Analysis ◽

16S Rrna Genes ◽

Rrna Genes ◽

Phenotypic Characteristics ◽

Cicer Arietinum L ◽

Mesorhizobium Ciceri ◽

Length Polymorphisms ◽

Reference Strains ◽

Tolerance To Salinity

Several phenotypic markers were used in this study to determine the biodiversity of rhizobial strains nodulating Cicer arietinum L. in various areas of Tunisia. They include symbiotic traits, the use of 21 biochemical substrates, and tolerance to salinity and pH. In addition, restriction fragment length polymorphisms (RFLPs) of PCR-amplified 16S rDNA were compared with those of reference strains. Numeric analysis of the phenotypic characteristics showed that the 48 strains studied fell into three distinct groups. This heterogeneity was highly supported by the RFLP analysis of 16S rRNA genes, and two ribotypes were identified. Chickpea rhizobia isolated from Tunisian soils are both phenotypically and genetically diverse. Results showed that 40 and 8 isolates were assigned, respectively, to Mesorhizobium ciceri and Mesorhizobium mediterraneum .

Download Full-text

Identification and Characterization of Leucocyclicin Q, a Novel Cyclic Bacteriocin Produced by Leuconostoc mesenteroides TK41401

Applied and Environmental Microbiology ◽

10.1128/aem.06348-11 ◽

2011 ◽

Vol 77 (22) ◽

pp. 8164-8170 ◽

Cited By ~ 61

Author(s):

Yoshimitsu Masuda ◽

Hiroshi Ono ◽

Hiroshi Kitagawa ◽

Haruo Ito ◽

Fuqin Mu ◽

...

Keyword(s):

Leuconostoc Mesenteroides ◽

Bacillus Coagulans ◽

Antimicrobial Spectrum ◽

Strong Activity ◽

Ionization Time ◽

Content Type ◽

Flight Mass Spectrometry ◽

Identification And Characterization ◽

Tof Ms

ABSTRACTThe culture supernatant ofLeuconostoc mesenteroidesTK41401, isolated from Japanese pickles, possessed antimicrobial activity against broad range of a bacterial genera and particularly strong activity againstBacillus coagulans, the major contaminant of pickles. An antimicrobial peptide was purified in three chromatographic steps, and its molecular mass was determined to be 6,115.59 Da by electrospray ionization time-of-flight mass spectrometry (ESI-TOF MS). The primary structure of this peptide was determined by amino acid and DNA sequencing, and these analyses revealed that it was translated as a 63-residue precursor. This precursor showed high similarity to the precursor of lactocyclicin Q, a cyclic bacteriocin produced byLactococcussp. strain QU 12. The molecular weight calculated after cyclization, which was presumed to involve the same process as in lactocyclicin Q (between L3 and W63), agreed with that estimated by ESI-TOF MS. This peptide was proved to be a novel cyclic bacteriocin, and it was termed leucocyclicin Q. The antimicrobial spectrum of this bacteriocin clearly differed from that of lactocyclicin Q, even though their primary structures were quite similar. This is the first report of a cyclic bacteriocin produced by a strain of the genusLeuconostoc.

Download Full-text