Search results for "Coccus"
showing 10 items of 1002 documents
A new fear in wine: Isolation of Staphylococcus epidermidis histamine producer
2016
Abstract Biogenic amines (BAs) are undesirable compounds in all foods and beverages because they may induce food-borne intoxications when consumed at high concentrations. The aim of this study was to identify the organism responsible for the synthesis of histamine in a Tempranillo red wine from Ribera de Duero D.O. (Denomination of origin), Spain. Bacteria present in wines after malolactic fermentation were isolated, identified and typed. Four strains of the species Oenococcus oeni and two strains of Staphylococcus epidermidis were found. None of the O. oeni strains produced histamine, cadaverine or putrescine, but one of the S. epidermidis strains (Pa) was able to produce all three in synt…
The Antisense RNA Approach: a New Application for In Vivo Investigation of the Stress Response of Oenococcus oeni, a Wine-Associated Lactic Acid Bact…
2015
ABSTRACT Oenococcus oeni is a wine-associated lactic acid bacterium mostly responsible for malolactic fermentation in wine. In wine, O. oeni grows in an environment hostile to bacterial growth (low pH, low temperature, and ethanol) that induces stress response mechanisms. To survive, O. oeni is known to set up transitional stress response mechanisms through the synthesis of heat stress proteins (HSPs) encoded by the hsp genes, notably a unique small HSP named Lo18. Despite the availability of the genome sequence, characterization of O. oeni genes is limited, and little is known about the in vivo role of Lo18. Due to the lack of genetic tools for O. oeni , an efficient expression vector in O…
Use of starter cultures ofLactobacillusto induce malolactic fermentation in wine
2017
Background and Aims Oenococcus oeni is the lactic acid bacteria species that best adapts to harsh wine conditions. This species is currently the main component of the malolactic starter cultures used in winemaking. Other species of lactic acid bacteria, however, such as Lactobacillus, can also conduct the malolactic fermentation, especially in low acidity wines. This study aimed to identify suitable Lactobacillus strains and inoculation methods to undertake the malolactic fermentation in wines with pH > 3.5. Methods and Results Six Lactobacillus strains of species L. mali (E4634), L. paracasei (E4539, E4541), L. plantarum (E4538, E4608) and L. satsumensis (E4555) were selected for their goo…
Lactic Acid Bacteria
2008
A typical lactic acid bacterium grown under standard conditions is aerotolerant, acid tolerant, organotrophic, and a strictly fermentative rod or coccus, producing lactic acid as a major end product. It lacks cytochromes and is unable to synthesize porphyrins. Its features can vary under certain conditions. Catalase and cytochromes may be formed in the presence of hemes and lactic acid can be further metabolized, resulting in lower lactic acid concentrations. Cell division occurs in one plane, except pediococci. The cells are usually nonmotile. They have a requirement for complex growth factors such as vitamins and amino acids. An unequivocal definition of LAB is not possible (Axelsson, Lac…
Identification and structural characterization of LytU, a unique peptidoglycan endopeptidase from the lysostaphin family
2017
AbstractWe introduce LytU, a short member of the lysostaphin family of zinc-dependent pentaglycine endopeptidases. It is a potential antimicrobial agent for S. aureus infections and its gene transcription is highly upregulated upon antibiotic treatments along with other genes involved in cell wall synthesis. We found this enzyme to be responsible for the opening of the cell wall peptidoglycan layer during cell divisions in S. aureus. LytU is anchored in the plasma membrane with the active part residing in the periplasmic space. It has a unique Ile/Lys insertion at position 151 that resides in the catalytic site-neighbouring loop and is vital for the enzymatic activity but not affecting the …
Microbial Succession in Spontaneously Fermented Grape Must Before, During and After Stuck Fermentation
2016
The microbial succession in spontaneously fermenting Riesling must was investigated from the beginning (pressing) until the end (sulphuring) of the fermentation in two harvest years (2008 and 2009) at a Moselle winery (Germany). In both years, the fermentation was interrupted by a stuck period. The length of the stuck period varied considerably (20 weeks in 2008 and one week in 2009). Different yeasts (Candida, Debaryomyces, Pichia, Hanseniaspora, Saccharomyces, Metschnikowia, Cryptococcus, Filobasidium and Rhodotorula) and bacteria (Gluconobacter, Asaia, Acetobacter, Oenococcus, Lactobacillus, Bacillus and Paenibacillus) were isolated successively by plating. The main fermenting organism w…
A new class of phenylhydrazinylidene derivatives as inhibitors of Staphylococcus aureus biofilm formation
2016
In the struggle against the emergence of the antibiotic resistance, new molecules targeting biofilm formation could be useful as adjuvant of conventional antibiotics. This study focused on a new class of 2-phenylhydrazinylidene derivatives as antivirulence agents. The compound 12e showed interesting activities against biofilm formation of all tested Staphylococcus aureus strains with IC50 ranging from 1.7 to 43 µM; compounds 12f and 13a resulted strong inhibitors of S. aureus ATCC 6538 and ATCC 29213 biofilm formation with IC50 of 0.9 and 0.8 µM, respectively. A preliminary study on the mechanism of action was carried on evaluating the inhibition of sortase A transpeptidase. Compound 12e re…
The unusual structure of Ruminococcin C1 antimicrobial peptide confers clinical properties.
2020
The emergence of superbugs developing resistance to antibiotics and the resurgence of microbial infections have led scientists to start an antimicrobial arms race. In this context, we have previously identified an active RiPP, the Ruminococcin C1, naturally produced by Ruminococcus gnavus E1, a symbiont of the healthy human intestinal microbiota. This RiPP, subclassified as a sactipeptide, requires the host digestive system to become active against pathogenic Clostridia and multidrug-resistant strains. Here, we report its unique compact structure on the basis of four intramolecular thioether bridges introduced post-translationally by a specific radical-SAM sactisynthase. This structure con…
Beta-Hemolytic Streptococcal Infective Endocarditis: Characteristics and Outcomes From a Large, Multinational Cohort
2020
Abstract Background Beta-hemolytic streptococci (BHS) are an uncommon cause of infective endocarditis (IE). The aim of this study was to describe the clinical features and outcomes of patients with BHS IE in a large multinational cohort and compare them with patients with viridans streptococcal IE. Methods The International Collaboration on Endocarditis Prospective Cohort Study (ICE-PCS) is a large multinational database that recruited patients with IE prospectively using a standardized data set. Sixty-four sites in 28 countries reported patients prospectively using a standard case report form developed by ICE collaborators. Results Among 1336 definite cases of streptococcal IE, 823 were ca…
An analysis in vivo of intracanal bacterial load before and after chemo-mechanical preparation: A comparative analysis of two irrigants and two activ…
2016
Background: The goals of this randomized double-blind trial were to assess the antimicrobial activity in vivo of Sodium hypochlorite (NaOCl) vs. chlorhexidine gluconate (CHX) used in combination either with EndoActivator® or IRRI S® files in patients with apical periodontitis. Material and Methods: A total of 120 patients with apical periodontitis (in single or multiple root canals) were randomly assigned to the four irrigation protocols outlined below: Group A: 5.25% sodium hypochlorite (NaOCl) + EndoActivator®; Group B: 5.25% NaOCl + IRRI S® files; Group C: 2% chlorhexidine gluconate (CHX) + EndoActivator®; Group D: 2% CHX + IRRI S® files. Paper points were used to collect microbiological…