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

2011 ◽  
Vol 77 (22) ◽  
pp. 8164-8170 ◽  
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.

scholarly journals Identification and Characterization of “Haemophilus quentini” Strains Causing Invasive Disease in Ontario, Canada (2016 to 2018)

2019 ◽  
Vol 57 (12) ◽  
Author(s):  
Julianne V. Kus ◽  
Michelle Shuel ◽  
Deirdre Soares ◽  
William Hoang ◽  
Dennis Law ◽  
...  
Keyword(s):  
Invasive Disease ◽  
Rrna Gene ◽  
Reference Laboratory ◽  
Childbearing Age ◽  
Ionization Time ◽  
Content Type ◽  
Flight Mass Spectrometry ◽  
Invasive Diseases ◽  
Identification And Characterization

ABSTRACT Haemophilus influenzae is a well-established human pathogen capable of causing a range of respiratory and invasive diseases. Since the 1970s, it has been observed that a nontypeable cryptic genospecies of H. influenzae, most often biotype IV, has been associated with the genitourinary tracts of females and with invasive neonatal infections. This distinct genospecies has been provisionally named “Haemophilus quentini.” Here, we report seven cases of invasive H. quentini disease in patients from Ontario, Canada, over a 2-year period. Significantly, while most reports of invasive disease with H. quentini to date have been in neonates, we observed five cases in adults (three in women of childbearing age and two in seniors) as well as two in neonates. Identification of H. quentini is challenging and was not possible for frontline laboratories, requiring work at the reference laboratory level. We describe in detail the biochemical results, matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-Tof MS) results, and PCR results with several targets, including the 16S rRNA gene and multilocus sequence typing (MLST) genes, for the seven Ontario H. quentini isolates and several controls. Our data, combined with those of other publications, support the fact that H. quentini is distinct from H. influenzae and Haemophilus haemolyticus. This organism is recognized as a pathogen of neonates, but we hypothesize that it may be underrecognized as an important pathogen in adults as well, particularly pregnant women. By sharing the detailed descriptions of these isolates, we hope to enable other laboratories to better identify H. quentini so that the true prevalence of this organism and disease can be explored.

scholarly journals Rapid Identification of Clinically Relevant Members of the Genus Exophiala by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry and Description of Two Novel Species, Exophiala campbellii and Exophiala lavatrina

2017 ◽  
Vol 55 (4) ◽  
pp. 1162-1176 ◽  
Author(s):  
Andrew M. Borman ◽  
Mark Fraser ◽  
Adrien Szekely ◽  
Daniel E. Larcombe ◽  
Elizabeth M. Johnson
Keyword(s):  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

ABSTRACT Exophiala is a ubiquitous pleomorphic genus comprising at least 40 species, many of which have been associated with superficial, visceral, or systemic infections in humans, other mammals, or cold-blooded animals. In this study, we investigated the potential of matrix-assisted laser desorption–ionization time of flight mass spectrometry (MALDI-TOF MS) for the identification of Exophiala species. A total of 89 isolates (including 50 human and 4 animal clinical isolates) stored in the National Collection of Pathogenic Fungi were identified by PCR amplification and sequencing of internal transcribed spacer region 1. Eighty-three of the isolates corresponded to 16 known species within Exophiala/Rhinocladiella . The remaining six isolates are shown by phylogenetic analyses based on four loci to represent two novel Exophiala species. Four isolates from domestic bathrooms which form a sister species with Exophiala lecanii-corni are described here as Exophiala lavatrina sp. nov. The remaining two isolates, both from subcutaneous infections, are distantly related to Exophiala oligosperma and are described here as Exophiala campbellii sp. nov. The triazoles and terbinafine exhibited low MICs against all Exophiala isolates in vitro . MALDI-TOF MS successfully distinguished all 18 species and identified all isolates after appropriate reference spectra were created and added to commercial databases. Intraspecific mean log scores ranged from 1.786 to 2.584 and were consistently significantly higher than interspecific scores (1.193 to 1.624), with the exception of E. lecanii-corni and E. lavatrina , for which there was considerable log score overlap. In summary, MALDI-TOF MS allows the rapid and accurate identification of a wide range of clinically relevant Exophiala species.

scholarly journals Evaluation of Matrix-Assisted Laser Desorption Ionization−Time of Flight Mass Spectrometry for Identification of Mycobacterium species, Nocardia species, and Other Aerobic Actinomycetes

2015 ◽  
Vol 54 (2) ◽  
pp. 376-384 ◽  
Author(s):  
S. P. Buckwalter ◽  
S. L. Olson ◽  
B. J. Connelly ◽  
B. C. Lucas ◽  
A. A. Rodning ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Aerobic Actinomycetes ◽  
Tof Ms ◽  
Matrix Assisted Laser

The value of matrix-assisted laser desorption ionization−time of flight mass spectrometry (MALDI-TOF MS) for the identification of bacteria and yeasts is well documented in the literature. Its utility for the identification of mycobacteria andNocardiaspp. has also been reported in a limited scope. In this work, we report the specificity of MALDI-TOF MS for the identification of 162Mycobacteriumspecies and subspecies, 53Nocardiaspecies, and 13 genera (totaling 43 species) of other aerobic actinomycetes using both the MALDI-TOF MS manufacturer's supplied database(s) and a custom database generated in our laboratory. The performance of a simplified processing and extraction procedure was also evaluated, and, similar to the results in an earlier literature report, our viability studies confirmed the ability of this process to inactivateMycobacterium tuberculosisprior to analysis. Following library construction and the specificity study, the performance of MALDI-TOF MS was directly compared with that of 16S rRNA gene sequencing for the evaluation of 297 mycobacteria isolates, 148Nocardiaspecies isolates, and 61 other aerobic actinomycetes isolates under routine clinical laboratory working conditions over a 6-month period. MALDI-TOF MS is a valuable tool for the identification of these groups of organisms. Limitations in the databases and in the ability of MALDI-TOF MS to rapidly identify slowly growing mycobacteria are discussed.

scholarly journals 4,6-α-Glucanotransferase, a Novel Enzyme That Structurally and Functionally Provides an Evolutionary Link between Glycoside Hydrolase Enzyme Families 13 and 70

2011 ◽  
Vol 77 (22) ◽  
pp. 8154-8163 ◽  
Author(s):  
Slavko Kralj ◽  
Pieter Grijpstra ◽  
Sander S. van Leeuwen ◽  
Hans Leemhuis ◽  
Justyna M. Dobruchowska ◽  
...  
Keyword(s):  
Glycoside Hydrolase ◽  
Lactobacillus Reuteri ◽  
Enzyme Reaction ◽  
Methylation Analysis ◽  
Ionization Time ◽  
Content Type ◽  
Flight Mass Spectrometry ◽  
Enzyme Families ◽  
Protein Enzyme

ABSTRACTLactobacillus reuteri121 uses the glucosyltransferase A (GTFA) enzyme to convert sucrose into large amounts of the α-d-glucan reuteran, an exopolysaccharide. Upstream ofgtfAlies another putative glucansucrase gene, designatedgtfB. Previously, we have shown that the purified recombinant GTFB protein/enzyme is inactive with sucrose. Various homologs ofgtfBare present in otherLactobacillusstrains, including theL. reuteritype strain, DSM 20016, the genome sequence of which is available. Here we report that GTFB is a novel α-glucanotransferase enzyme with disproportionating (cleaving α1→4 and synthesizing α1→6 and α1→4 glycosidic linkages) and α1→6 polymerizing types of activity on maltotetraose and larger maltooligosaccharide substrates (in short, it is a 4,6-α-glucanotransferase). Characterization of the types of compounds synthesized from maltoheptaose by matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS), methylation analysis, and 1-dimensional1H nuclear magnetic resonance (NMR) spectroscopy revealed that only linear products were made and that with increasing degrees of polymerization (DP), more α1→6 glycosidic linkages were introduced into the final products, ranging from 18% in the incubation mixture to 33% in an enriched fraction. In view of its primary structure, GTFB clearly is a member of the glycoside hydrolase 70 (GH70) family, comprising enzymes with a permuted (β/α)8barrel that use sucrose to synthesize α-d-glucan polymers. The GTFB enzyme reaction and product specificities, however, are novel for the GH70 family, resembling those of the GH13 α-amylase type of enzymes in using maltooligosaccharides as substrates but differing in introducing a series of α1→6 glycosidic linkages into linear oligosaccharide products. We conclude that GTFB represents a novel evolutionary intermediate between the GH13 and GH70 enzyme families, and we speculate about its origin.

scholarly journals Molecular characterization of a novel bla CTX-M-3-carrying Tn6741 transposon in Morganella morganii isolated from swine

2020 ◽  
Vol 69 (8) ◽  
pp. 1089-1094
Author(s):  
Xingwei Luo ◽  
Yajun Zhai ◽  
Dandan He ◽  
Xiaodie Cui ◽  
Yingying Yang ◽  
...  
Keyword(s):  
Type Species ◽  
Susceptibility Testing ◽  
Morganella Morganii ◽  
Ionization Time ◽  
Content Type ◽  
Genetic Environment ◽  
Link Type ◽  
Flight Mass Spectrometry ◽  
First Time

Introduction. The bla CTX-M-3 gene has rarely been reported in Morganella morganii strains and its genetic environment has not yet been investigated. Aim. To identify the bla CTX-M-3 gene in M. morganii isolated from swine and characterize its genetic environment. Methodology. A M. morganii isolate (named MM1L5) from a deceased swine was identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and subjected to antimicrobial susceptibility testing. The bla genes were detected and then the genetic location and environment of bla CTX-M-3 were investigated by Southern blot and PCR mapping, respectively. The M. morganii bla CTX-M-3 gene was cloned and expressed in Escherichia coli . Results. Isolate MM1L5 harboured the bla CTX-M-3 and bla TEM-1 genes. The bla CTX-M-3 gene, located on the chromosome, was co-carried with an IS26 and bla TEM-1 gene by a novel 6361 bp IS26-flanked composite transposon, designated Tn6741. This transposon consisted of a novel bla CTX-M-3-containing module, IS26-ΔISEcp1-bla CTX-M-3-Δorf477-IS26 (named Tn6710), and a bla TEM-1-containing module, IS26-Δorf477-bla TEM-1-tnpR-IS26, differing from previous reports. Phylogenetic analysis showed a significant variation based on the sequence of Tn6741, as compared to those of other related transposons. Interestingly, although the cloned bla CTX-M-3 gene could confer resistance to ceftiofur, cefquinome, ceftriaxone and cefotaxime, one amino acid substitution (Ile-142-Thr) resulted in a significant reduction of resistance to these antimicrobials. Conclusion. This is the first time that bla CTX-M-3 has been identified on a chromosome from a M. morganii isolate. Furthermore, the bla CTX-M-3 gene was located with an IS26 element and bla TEM-1 gene on a novel IS26-flanked composite transposon, Tn6741, suggesting that Tn6741 might act as a reservoir for the bla CTX-M-3 and bla TEM-1 genes and may become an important vehicle for their dissemination among M. morganii .

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