Search results for "Coccus"
showing 10 items of 1002 documents
Evaluation of yogurt and various beverages as carriers of lactic acid bacteria producing 2-branched (1,3)-β-D-glucan
2011
8 páginas, 2 figuras, 2 tablas -- PAGS nros. 3271-3278
Pneumococcal HxxHxH triad – Copper(II) interactions – How important is the ‘x’?
2019
Abstract PhtA, a Streptococcus pneumoniae polyhistidine triad protein, which contributes to virulence by interacting with components of the immune system, by being involved in adherence of bacteria and in Zn(II) uptake, contains five copies of the HxxHxH sequence. Since this motif is also present in numerous Cu(II) binding proteins, we decided to focus on the bioinorganic chemistry of copper(II) with three of such PhtA repeats, in order to understand which of the PhtA triads binds Cu(II) with the highest affinity and explain if Cu(II) would be able to outcompete Zn(II) from its native binding site under physiological metal concentrations.
Citrate permease gene expression inLactococcus lactissubsp.lactisstrains IL1403 and MG1363
1996
Citrate permease gene expression in the plasmid-free Lactococcus lactis strains IL1403 and MG1363 was studied. The ability to transport citrate results in diacetyl and acetoin production in IL1403 but not in MG1363. Citrate lyase, α-acetolactate decarboxylase, diacetyl and acetoin reductase were detected in IL1403. These data show that L. lactis ssp. lactis strain IL1403 is a citrate permease mutant of the biovar. diacetylactis. Immunological analysis revealed the α-and β-subunits of citrate lyase not only in IL1403 but also in MG1363 where no citrate lyase activity was found.
pH Homeostasis and Citric Acid Utilization: Differences Between Leuconostoc mesenteroides and Lactococcus lactis
1997
This study presents the effects of citric acid and extracellular pH (pHe) on the intracellular pH (pHi) of wild-type and citrate negative variants (cit−) Leuconostoc mesenteroides subsp. mesenteroides (Ln. mesenteroides M) and Lactococcus lactis subsp. lactis bv. diacetylactis (L. lactis LD). A recent method using a pH-sensitive fluorescent indicator carboxyfluorescein succinimidyl ester (cFSE) was adapted to measure the pHi of these two lactic acid bacteria in resting cells. Energized cells with 10 mM lactose of Ln. mesenteroides M and L. lactis LD modified their pH gradient (ΔpH) in the same manner; when the pHe was decreased from 7 to 4, the pHi decreased from 7 to about 5. The adjunctio…
Exoenzymes of Wine Microorganisms
2008
The production of wine from grape juice is predominantly the result of enzymatic reactions. The enzymes originate from the grape itself, from epiphytic fungi like Botrytis cinerea colonizing the grape surface and finally from yeasts and bacteria growing in the must until termination of alcoholic fermentation. Especially nonSaccharomyces yeasts, also called “wild” yeasts, belonging to the genera Kloeckera, Candida, Debaryomyces, Rhodotorula, Pichia, Zygosaccharomyces, Hanseniaspora, Kluyveromyces, and Metschnikowia produce and secrete several enzymes (esterases, glycosidases, lipases, glucanases, proteases, cellulases, etc.) to the periplasmatic space and the medium where they may interact w…
Transport of Sugars and Sugar Alcohols by Lactic Acid Bacteria
2008
Lactic acid bacteria (LAB) play an important role in the fermentation of beverages like wine and beer, and in the production of dairy products, sour dough, sausages and cheese. The knowledge of the genome sequence offers an insight into the metabolism of the bacteria and provides means to optimize the manufacturing of the products. By now genomes of several lactic acid bacteria are sequenced, including wine related bacteria Oenococcus oeni PSU-1, Pediococcus pentosaceus ATCC 25745, Leuconostoc mesenteroides ATCC 8293 (http://www.jgi.doe.gov/; Klaenhammer et al. 2002; Mills et al. 2005) and Lactobacillus plantarum WCFS1 (http://www.cmbi. ru.nl/plantarum/; http://www.lacplantcyc.nl/; Kleerebe…
Inhibition of bacterial virulence factors of foodborne pathogens by paprika (Capsicum annuum L.) extracts
2022
Abstract Capsicum annuum extracts of different polarities were tested for their antimicrobial, antibiofilm, and anti-Quorum sensing (QS) activity against several pathogenic microorganisms and possible toxic effects using an in vivo model (Galleria mellonella L.). Hexane (HE) and Chloroform extract (CE) were the most active in inhibiting biofilm formation of the eight bacteria tested, with inhibition percentages between 22 and 88% for a concentration of 100 μg/mL. These extracts were potent inhibitors of Staphylococcus aureus biofilm, and microscopy analysis confirmed a significant reduction in adhered cells. Moreover, polystyrene surfaces coated with these extracts decreased Staph. aureus a…
ChemInform Abstract: One-Step Synthesis, Crystallographic Studies and Antimicrobial Activity of New 4-Diazopyrazole Derivatives.
2010
Summary A number of new 4-diazopyrazole derivatives were prepared by the reaction of 1- R -3-methyl-5(R 1 -substituted)benzamidopyrazoles with a sevenfold excess of nitrous acid in acetic medium. The compounds were tested for activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus faecalis, Listeria monocytogenes, Candida albicans, Candida tropicalis and Paecilomyces varioti . The highest microbial susceptibility was shown by Gram-positive bacteria, with minimum inhibitory concentrations (MIC) in the range 0.5–12.5 μg/mL. For S aureus the R 1 substituents were screened utilizing the Topliss operational scheme. The 4-nitro g…
An investigation of the bacteriocinogenic potential of lactic acid bacteria associated with wheat (triticum durum) kernels and non-conventional flours
2008
One hundred and thirty-seven lactic acid bacteria (LAB), previously isolated from wheat (Triticum durum) grains and non-conventional flour samples, were tested for the production of antibacterial substances. A total of 16 strains (5 Enterococcus faecium, 5 Enterococcus mundtii, 4 Pediococcus pentosaceus, 1 Lactobacillus coryniformis and 1 Lactococcus garvieae) were found to inhibit the growth of Listeria innocua. The antibacterial activities were preliminarily investigated for their general behaviour with proteolytic (proteinase K, protease B and trypsin), amylolytic (α-amylase) and lipolytic (lipase) enzymes, after heat treatment, and exposure to different pHs and ethanol concentrations. B…
Staphylococcus aureus alpha-toxin attack on human platelets promotes assembly of the prothrombinase complex.
1990
alpha-Toxin, the major cytolysin of Staphylococcus aureus, promotes blood coagulation by its attack on human platelets (Bhakdi S., Muhly, M., Mannhardt, U., Hugo, F., Klapettek, K., Mueller-Eckhardt, C., and Roka, L. (1988) J. Exp. Med. 168, 527-542). In the present study we demonstrate that toxin attack on gel-filtered human platelets initiates the assembly of prothrombinase complexes at rates up to 10-fold of controls. Treatment of platelets with 0.1 microgram/ml alpha-toxin resulted in generation of 1.4 units of thrombin/10(8) platelets. A similar rate of thrombin generation was noted when platelets were subjected to three cycles of freezing and thawing. However, the alpha-toxin-induced …