ABSTRACT Legionella pneumophila is the etiological agent of Legionnaires' disease. Crucial to pathogenesis this intracellular pathogen its ability subvert host cell defenses, permitting replication in specialized vacuoles within cells. The Dot/Icm type IV secretion system (T4SS), which translocates a large number bacterial effectors into cell, absolutely required for rerouting phagosome. Many display distinctive eukaryotic domains, among are protein kinase domains. In silico analysis and...

Legionella pneumophila, the etiological agent of legionellosis, replicates within phagocytic cells. Crucial to biogenesis replicative vacuole is Dot/Icm type 4 secretion system, which translocates a large number effectors into host cell cytosol. Among them LegK2, protein kinase that plays key role in infection. Here, we identified actin nucleator ARP2/3 complex as target LegK2. LegK2 phosphorylates ARPC1B and ARP3 subunits complex. LegK2-dependent phosphorylation triggers global cytoskeleton...

The exopolysaccharide (EPS) biosynthesis gene clusters of four Lactobacillus rhamnosus strains consist chromosomal DNA regions 18·5 kb encoding 17 ORFs that are highly similar among the strains. However, under identical conditions, EPS production varies considerably these strains, from 61 to 1611 mg l −1 . Fifteen genes co-transcribed starting first promoter upstream wzd Nevertheless, five transcription start sites were identified by 5′-RACE PCR analysis, and associated with sequences , rmlA...

Investigation of the chromosomal region downstream lacZ gene from Lactobacillus delbrueckii subsp. bulgaricus revealed presence a (prtB) encoding proteinase 1,946 residues with predicted molecular mass 212 kDa. The deduced amino acid sequence showed that PrtB displays significant homology N termini and catalytic domains lactococcal PrtP cell surface proteinases is probably synthesized as preproprotein. However, cysteine near histidine active site suggests belongs to subfamily subtilisins....

The proline iminopeptidase (PepIP) of Lactobacillus delbrueckii subsp. bulgaricus is a major peptidase located in the cell envelope. Its structural gene (pepIP) has been cloned into pUC18 and expressed at very high level Escherichia coli to give PepIP activity 15000-fold higher than that found L. bulgaricus. nucleotide sequence pepIP revealed an open reading frame 295 codons encoding protein with predicted M r 33006, which consistent apparent size product. amino acid shows significant...

ABSTRACT In order to develop a new system for the analysis of capsular biosynthetic pathways we have explored possibility expressing type 3 polysaccharide (CPS) from pathogen Streptococcus pneumoniae in Lactococcus lactis , an unencapsulated lactic acid bacterium being developed as vaccine delivery vehicle mucosal immunization. Only three four CPS biosynthesis genes were found be necessary abundant formation (120 mg liter −1 ) extracellular L. implying role 3-specific synthase transport or...

Proline iminopeptidase (PepIP) is a major peptidase in Lactobacillus delbrueckii subsp. bularicus CNRZ397, encoded by the pepIP gene. Amplification and expression of this gene Escherichia coli K12 resulted very high level enzyme production. Moreover, export into E. periplasm 45% PepIP activity allowed us to purify easily single ion-exchange chromatography step. trimer Mr 100000 , composed three identical subunits. In presence 0.1% BSA, was optimal at pH 6-7 stable temperatures below 40...

Pneumonia associated with Iegionnaires's disease is initiated in humans after inhalation of contaminated aerosols. In the environment, Legionella pneumophila thought to survive and multiply as an intracellular parasite within free-living amoeba. genome L. Lens, we identified a unique gene, tolC, encoding protein that highly homologous outer membrane TolC Escherichia coli. Deletion tolC by allelic exchange caused increased sensitivity various drugs. The complementation mutation trans restored...

Legionella pneumophila is a Gram-negative pathogen found mainly in water, either free-living form or within infected protozoans, where it replicates. This bacterium can also infect humans by inhalation of contaminated aerosols, causing severe pneumonia called legionellosis Legionnaires' disease. The involvement type II and IV secretion systems the virulence L. now well documented. Despite bioinformatic studies showing that I system (T1SS) could be present this pathogen, functionality based...

Objectives: A previous study on 12 in vitro-selected azithromycin-resistant Legionella pneumophila lineages showed that ribosomal mutations were major macrolide resistance determinants. In addition to these mechanisms have been well described many species, upstream of lpeAB operon, homologous acrAB Escherichia coli, identified two lineages. this study, we investigated the role LpeAB and L. pneumophila. Methods: The was studied by testing antibiotic susceptibility WT, deleted complemented...

Fifteen bismuth oxyhalides were synthetized, including BiOX, BiOX/BixOyXz, heterostructures and BiOXxY1−x (X, Y = Cl, Br, I) solid solutions. The photocatalytic activity intermediates formation of as-prepared bismuth-based semiconductors (BBS) compared with the benchmark TiO2 P25 photocatalyst for NOx air purification, phenol decomposition, E.Coli bacteria inactivation. possessed highest oxidation rate (K 0.003 min−1) NO degradation efficiency (η 38 %) when exposed to UV light, but also...

ABSTRACT The oral bacterium Streptococcus gordonii expresses two cell wall-associated polypeptides, designated SspA (1,542 amino acid residues) and SspB (1,462 residues), that have 70% sequence identity. These polypeptides are members of the antigen I/II family streptococcal adhesins mediate binding streptococci to salivary glycoproteins, collagen, other microorganisms such as Actinomyces naeslundii . To determine if differential properties, coding sequences sspA sspB genes were cloned into...

Journal Article Atypical citrate‐fermenting Lactococcus lactis strains isolated from dromedary's milk Get access H. Drici, Drici Université de Lyon, France; Villeurbanne; INSA CNRS UMR5240 Microbiologie, Adaptation et Pathogénie, FranceLaboratory of Applied Microbiology, University Es‐Sania, Oran, Algérie Search for other works by this author on: Oxford Academic Google Scholar C. Gilbert, Gilbert France M. Kihal, Kihal Laboratory D. Atlan Danièle Atlan, Lyon 1, France. E‐mail:...

Legionella pneumophila is an intracellular pathogen which replicates within protozoan cells and can accidently infect alveolar macrophages, causing acute pneumonia in humans. The second messenger cyclic di-GMP (c-di-GMP) has been shown to play key roles the regulation of various bacterial processes, including virulence. While investigating function 22 potential c-di-GMP-metabolizing enzymes L. Lens strain, we found three that directly contribute its ability both mammalian cells. These...

Abstract Background Several cases of legionellosis have been diagnosed in the same French thermal spa 1986, 1994 and 1997. L. pneumophila serogroup 1 (Lp1) strains isolated from several patients, but source contamination was not identified despite presence different Lp1 water samples three natural springs feeding at this period. Results Our strategy to investigate (Lp) biofilms developed a sulphur-rich warm spring contaminated site. Biofilm analysis revealed Lp serogroups (Lp1, Lp10 Lp12)....

Escherichia coli is able to reduce azo compounds such as methyl red (MR) and nitro 7-nitrocoumarin-3-carboxylic acid (7NCCA). The aim of this study was clarify the specificity major E. reductases.Enzymatic assays with pure enzymes obtained after cloning, overproduction purification under native or denaturing conditions were performed on three enzymes: AzoR, NfsA NfsB. Their dependence putative cofactors flavin mononucleotide (FMN), NADH NADPH studied well reductase capacity mutants depleted...

Abstract Development of low salt cucumber fermentation processes present opportunities to reduce the amount sodium chloride (NaCl) that reaches fresh water streams from industrial activities. The objective this research was translate brined with calcium (CaCl 2 ) instead NaCl commercial scale production. Although CaCl fermentations were stable in laboratory experiments, trials using 6440 L open‐top tanks rapidly underwent secondary fermentation. It understood a limited air purging routine,...

Nitroreductases, NAD(P)H dependent flavoenzymes, are found in most of bacterial species. Even if Enterococcus faecalis strains seems to present such activity because their sensitivity nitrofurans, no enzyme has been described. Nitroreductases were separated others reductases due capacity reduce nitro compounds. They further classified based on preference cofactor: NADH and/or NADPH. However, recently, azoreductases have studied for strong compounds, especially pro-drugs. This result suggests...

Whole cells of Lactobacillus delbrueckii subsp. bulgaricus CNRZ 397 ( Lb. 397) are able to hydrolyse α- and β-caseins. We have isolated a mutant altered for growth in milk unable or β-casein. Normal was restored by adding amino acids tryptone milk. No significant difference between the peptidase activities parent strains observed. The cell surface caseinolytic three lactobacilli species Lactococcus lactis Lc. ) were compared. As expected, characteristics proteinase activity casei similar...

Retrophosphorylation of the histidine kinase CheA in chemosensory transduction chain is a widespread mechanism for efficient dephosphorylation activated response regulator. First discovered Sinorhizobium meliloti, main regulator CheY2-P shuttles its phosphoryl group back to CheA, while second regulator, CheY1, serves as sink surplus groups from CheA-P. We have identified new component this phospho-relay system, small 97-amino-acid protein named CheS. CheS has no counterpart enteric bacteria...

Summary: Lactobacillus helveticus ITGL1 is able to hydrolyse many amino-acyl and dipeptidyl-p-nitroanilides. Analysis of heat inactivation kinetics, metal ion protease inhibitor effects, the subcellular location aminopeptidase activities in both parental strain mutants deficient lysyl-p-nitroanilide hydrolysis, led characterization two cell-wall-associated aminopeptidases. APII APIV. APII, which catalysed L-lysine p-nitroanilide was purified about 28-fold homogeneity from cell-wall extracts...

Legionnaires' Disease (LD) is a severe pneumonia mainly caused in Europe by Legionella pneumophila serogroup 1 (Lp1). Sequence-based typing methods reveal that some sequence types (ST) are overrepresented clinical samples such as ST1 and ST47, suggesting strains more fit for infection than others. In the present study, collection of 108 Lp1 isolates were used to evaluate strain-dependent immune responses from human macrophages. Clinical induced differential TNFα secretion significantly...