scholarly journals Conserved pheromone production, response and degradation byStreptococcus mutans

2019 ◽  
Author(s):  
Antonio Pedro Ricomini Filho ◽  
Rabia Khan ◽  
Heidi Aarø Åmdal ◽  
Fernanda C. Petersen
Keyword(s):  
Proteolytic Activity ◽  
Late Response ◽  
Protease Gene ◽  
Endogenous Production ◽  
Different Strains ◽  
Isogenic Mutants ◽  
Culture Supernatants ◽  
Luciferase Reporters ◽  
Production Response ◽  
Bacteriocin Gene

ABSTRACTStreptococcus mutans, a bacterium with high cariogenic potential, coordinates competence for natural transformation and bacteriocin production via the XIP and CSP pheromones. CSP is effective in inducing bacteriocin responses, but not competence in chemically defined media (CDM). This is in contrast to XIP, which is a strong inducer of competence in CDM, but can also stimulate bacteriocin genes as a late response. Inter-connections between the pathways activated by the two pheromones have been characterized in certain detail inS. mutansUA159, but it is mostly unknown whether such findings are representative for the species. In this study, we used bioassays based on luciferase reporters for the bacteriocin genecipBand the alternative sigma factorsigXto investigate variousS. mutansisolates for production and response to CSP and XIP pheromones in CDM. Similar toS. mutansUA159, endogenous CSP was undetectable in the culture supernatants of all tested strains. During optimization of the bioassay using thecipBreporter, we discovered that the acivity of exogenous CSP used as a standard was reduced over time duringS. mutansgrowth. Using a FRET-CSP reporter peptide, we found thatS. mutansUA159 was indeed able to degrade CSP, and that such proteolytic activity was not significantly different in isogenic mutants with deletion of the protease genehtrA, or the competence genessigX, oppD, andcomR. CSP proteolysis was also detected in all the wild type strains, indicating that such activity is conserved inS. mutans. For the XIP pheromone, endogenous production was observed in the supernatants of all 34 tested strains at peak concentrations in culture supernatants that varied between 200 nM and 26000 nM. Transformation in the presence of exogenous XIP was detected in all, but one, of the isolates. The efficiency of transformation varied, however, among the different strains, and for those with the highest transformation rates, endogenous XIP peak concentrations in the supernatants were above 2000 nM XIP. We conclude that XIP production and inducing effect on transformation, as well as proteolytic activity leading to the inactivation of CSP are conserved functions among differentS. mutansisolates. Understanding the functionality and conservation of pheromone systems inS. mutansmay lead to novel strategies to prevent or treat unbalances in oral microbiomes that may favour diseases.

scholarly journals Cysteine protease gene expression and proteolytic activity during senescence of Alstroemeria petals

2002 ◽  
Vol 53 (367) ◽  
pp. 233-240 ◽  
Author(s):  
Carol Wagstaff ◽  
Michael K. Leverentz ◽  
Gareth Griffiths ◽  
Brian Thomas ◽  
Usawadee Chanasut ◽  
...  
Keyword(s):  
Gene Expression ◽  
Proteolytic Activity ◽  
Cysteine Protease ◽  
Protease Gene ◽  
Cysteine Protease Gene

Genomic diversity and immunomodulatory activity of Lactobacillus plantarum isolated from dairy products

2017 ◽  
Vol 8 (4) ◽  
pp. 597-604 ◽  
Author(s):  
M. Zago ◽  
E. Scaltriti ◽  
B. Bonvini ◽  
M.E. Fornasari ◽  
G. Penna ◽  
...  
Keyword(s):  
Immune Response ◽  
Lactobacillus Plantarum ◽  
Dairy Products ◽  
Genomic Diversity ◽  
Immunomodulatory Activity ◽  
Preclinical Models ◽  
Riboflavin Production ◽  
Commercial Use ◽  
Different Strains ◽  
Culture Supernatants

In this study, we aimed to investigate some functional characteristics and the immunomodulatory properties of three strains of Lactobacillus plantarum of dairy origin which, in a previous screening, showed to be candidate probiotics. Genome sequencing and comparative genomics, which confirmed the presence of genes involved in folate and riboflavin production and in the immune response of dendritic cells (DCs), prompted us to investigate the ability of the three strains to accumulate the two vitamins and their immunomodulation properties. The ability of the three strains to release antioxidant components in milk was also investigated. Small amounts of folate and riboflavin were produced by the three strains, while they showed a good antioxidant capacity in milk with FRAP method. The immune response experiments well correlated with the presence of candidate genes influencing in DCs cytokine response to L. plantarum. Specifically, the amounts of secreted cytokins by DCs after stimulation with cells of Lp790, Lp813 and Lp998 resulted pro-inflammatory whereas stimulation with culture supernatants (postbiotics) inhibited the release of interleukin (IL)-12p70 and increased the release of the anti-inflammatory IL-10 cytokine. This study adds further evidence on the importance of L. plantarum in human health. Understanding how probiotics (or postbiotics) work in preclinical models can allow a rational choice of the different strains for clinical and/or commercial use.

scholarly journals Identification of Major Glucan-Associated Cell Wall Proteins of Candida albicans and Their Role in Fluconazole Resistance

2002 ◽  
Vol 46 (6) ◽  
pp. 1688-1694 ◽  
Author(s):  
Letizia Angiolella ◽  
Mia M. Micocci ◽  
Simona D'Alessio ◽  
Antonietta Girolamo ◽  
Bruno Maras ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Direct Sequencing ◽  
Cell Wall Proteins ◽  
Secretory Material ◽  
Fluconazole Resistance ◽  
Associated Proteins ◽  
Resistant Strains ◽  
Different Strains ◽  
Culture Supernatants

ABSTRACT Identification of major glucan-associated proteins (GAPs) of the cell wall of a number of Candida albicans isolates susceptible or resistant to fluconazole (FLC) was addressed by direct sequencing of the protein bands resolved by unidimensional gel electrophoresis. Changes in the GAP compositions of the different strains grown in the presence of the drug were also investigated. In the FLC-susceptible strains, the major (more abundant) GAPs were enolase (46 kDa), two isoforms of phosphoglyceromutase (32 and 29 kDa), and two β-(1-3)-exoglucanases (44 and 34 kDa), one of which (the 34-kDa component) was glycosylated. When these strains were grown in the presence of FLC there were substantial decreases in the intensities of the two enzymes of the glycolytic pathway (enolase and the phosphoglyceromutases), which were apparently replaced by enhancement of the exoglucanase constituents, particularly the 44-kDa one. This GAP pattern closely mimicked that observed in the FLC-resistant strains whether they were grown in the presence or in the absence of the drug. Both the enolase and the exoglucanase constituents were detected in the culture supernatants of FLC-treated cells, together with substantial amounts of highly glycosylated, probably mannoprotein secretory material, suggesting that FLC may cause marked alterations of GAP incorporation into the cell wall. Altogether, we were able to identify all major GAP constituents and monitor their distributions in the cell wall of C. albicans during treatment with FLC. The near equivalence of the GAP profile for the FLC-susceptible strain grown in the presence of FLC to that for the FLC-resistant strain suggests that the effects of the drug on GAPs may be stably incorporated into the cell wall of the fungus upon acquisition of resistance.

Evaluation of the Proteolytic Activity Present in Cho Cell Culture Supernatants

1997 ◽  
pp. 295-300
Author(s):  
C. Tans ◽  
S. Wattiaux De Coninck ◽  
M.-M. Gonze ◽  
L. Fabry
Keyword(s):  
Cell Culture ◽  
Proteolytic Activity ◽  
Cho Cell ◽  
Cho Cell Culture ◽  
Culture Supernatants

scholarly journals Helicobacter pylori Supernatants Cause Epithelial Cytoskeletal Disruption That Is Bacterial Strain and Epithelial Cell Line Dependent but Not Toxin VacA Dependent

2003 ◽  
Vol 71 (6) ◽  
pp. 3623-3627 ◽  
Author(s):  
James R. Bebb ◽  
Darren P. Letley ◽  
Joanne L. Rhead ◽  
John C. Atherton
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cell ◽  
Cell Line ◽  
Broth Culture ◽  
Epithelial Cell Line ◽  
Vacuolating Cytotoxin ◽  
Epithelial Cell Lines ◽  
Isogenic Mutants ◽  
Culture Supernatants ◽  
Cytoskeletal Disruption

ABSTRACT We show here that Helicobacter pylori broth culture supernatants disrupt the actin cytoskeleton of epithelial cell lines, leading to cell rounding and apoptosis through anoikis. We demonstrate that there are marked quantitative differences between strains and that there are different cell line sensitivities. By constructing VacA null isogenic mutants, we show that the effect is not due to the vacuolating cytotoxin.

scholarly journals The effect of phytohormones on the growth, cellulose production and pellicle properties of Gluconacetobacter xylinus ATCC 53582

2013 ◽  
Vol 2 (1s) ◽  
pp. 7 ◽  
Author(s):  
Osama Qureshi ◽  
Hira Sohail ◽  
Andrew Latos ◽  
Janice L. Strap
Keyword(s):  
Bacterial Cellulose ◽  
High Performance ◽  
Crystallinity Index ◽  
Cellulose Synthesis ◽  
Gluconacetobacter Xylinus ◽  
Cellulose Production ◽  
Endogenous Production ◽  
Microbe Interactions ◽  
Wet Weight ◽  
Culture Supernatants

<em>Gluconacetobacter xylinus</em> is a plant-associated bacterium best studied for its cellulose production. Bacterial cellulose is important in facilitating plant-microbe interactions but little is known about the effect that exogenous phytohormones have on bacterial cellulose synthesis or the growth of <em>G. xylinus</em>. We characterized the growth, development and effect on pellicle characteristics caused by exogenous indole-3- acetic acid (IAA), gibberellic acid (GA), abscisic acid (ABA) and zeatin (Z) over a range of concentrations (1 nM to 100 &mu;M). These phytohormones are plant growth regulators known to be involved plant development including fruit ripening and stress tolerance. Each of these hormones stimulated <em>G. xylinus</em> growth and influenced its pellicle characteristics. Exogenous IAA had the greatest effect on <em>G. xylinus</em> pellicles. Growth in IAA produced thin pellicles with very little cellulose. In general, pellicle wet weight was inversely proportional to the bacterial cellulose yield when cultures were grown in the presence of ABA, suggesting ABA influenced pellicle density and hydration. The crystallinity index, CI (IR) of cellulose produced in the presence of each phytohormone over a variety of concentrations was determined by Fourier transform infrared spectroscopy. The observed effect on cellulose crystallinity was concentration and hormone dependent. GA caused the greatest alterations in crystallinity with the highest CI (IR)=0.94 at 1 &mu;M and the lowest CI (IR)=0.47 at 500 nM. Endogenous production of hormones by <em>G. xylinus</em> was investigated by high performance liquid chromatography of extracts prepared from both cell pellets and culture supernatants. We found <em>G. xylinus</em> synthesized GA, ABA and Z but did not produce IAA.

scholarly journals Role of RgpA, RgpB, and Kgp Proteinases in Virulence of Porphyromonas gingivalis W50 in a Murine Lesion Model

2001 ◽  
Vol 69 (12) ◽  
pp. 7527-7534 ◽  
Author(s):  
Neil M. O'Brien-Simpson ◽  
Rita A. Paolini ◽  
Brigitte Hoffmann ◽  
Nada Slakeski ◽  
Stuart G. Dashper ◽  
...  
Keyword(s):  
Proteolytic Activity ◽  
Type Strain ◽  
Wild Type Strain ◽  
Viable Cell ◽  
Wild Type ◽  
Whole Cell ◽  
Isogenic Mutant ◽  
Cell Dose ◽  
Viable Cells ◽  
Isogenic Mutants

ABSTRACT Extracellular Arg-x- and Lys-x-specific cysteine proteinases are considered important virulence factors and pathogenic markers forPorphyromonas gingivalis, a bacterium implicated as a major etiological agent of chronic periodontitis. Three genes.rgpA, rgpB, and kgp,encode an Arg-x-specific proteinase and adhesins (RgpA), an Arg-x-specific proteinase (RgpB), and a Lys-x-specific proteinase and adhesins (Kgp), respectively. The contribution to pathogenicity of each of the proteinase genes of P. gingivalis W50 was investigated in a murine lesion model using isogenic mutants lacking RgpA, RgpB, and Kgp. Whole-cell Arg-x-specific proteolytic activity of both the RgpA− and RgpB− isogenic mutants was significantly reduced (3- to 4-fold) relative to that of the wild-type W50. However, for the Kgp− isogenic mutant, whole-cell Arg-x activity was similar to that of the wild-type strain. Whole-cell Lys-x proteolytic activity of the RgpA− and RgpB− mutants was not significantly different from that of wild-type W50, whereas the Kgp− mutant was devoid of Lys-x whole-cell proteolytic activity. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis using proteinase-specific antibodies of cell sonicates of the wild-type and mutant strains showed that the proteinase catalytic domain of each of the mutants was not expressed. This analysis further showed that RgpB appeared as 72- and 80-kDa bands, and the catalytic domains of RgpA and Kgp appeared as processed 45-kDa and 48-kDa bands, respectively. In the murine lesion model, mice were challenged with three doses of each mutant and wild-type strain. At the lower dose (3.0 × 109 viable-cells), no lesions were recorded for each of the mutants, whereas wild-type W50 induced large ulcerative lesions. At a dose of 6.0 × 109 viable-cells, all the mice challenged with the wild-type strain died, whereas mice challenged with the RgpA− and RgpB− isogenic mutants did not die but developed lesions. Mice challenged with the Kgp−isogenic mutant at this dose did not develop lesions. At a 1.2 × 1010 viable-cell dose, only 40% of mice challenged with the Kgp− mutant developed lesions, and these lesions were significantly smaller than lesions induced by the wild-type strain at the 3.0 × 109 viable-cell dose. All the mice challenged with the RgpA− mutant died at the 1.2 × 1010 viable-cell dose, whereas only 20% died when challenged with the RgpB− mutant at this dose. Wild-type phenotype was restored to the RgpB− mutant by complementation with plasmid pNJR12::rgpBcontaining the rgpB gene. There was no difference between the pNJR12::rgpB-complemented RgpB− mutant and the wild-type W50 strain in whole-cell Arg-x activity, protein profile, or virulence in the murine lesion model. These results show that the three proteinases, RgpA, RgpB, and Kgp, all contributed to virulence of P. gingivalis W50 in the murine lesion model and that the order in which they contributed was Kgp ≫ RgpB ≥ RgpA.

Common Characteristics of the Swiss and Argentine Strains of Clostridium botulinum Type G1

1985 ◽  
Vol 48 (1) ◽  
pp. 7-10 ◽  
Author(s):  
HAIM M. SOLOMON ◽  
DONALD A. KAUTTER ◽  
RICHARD K. LYNT
Keyword(s):  
Proteolytic Activity ◽  
Yeast Extract ◽  
Clostridium Botulinum ◽  
Soil Extract ◽  
Human Origin ◽  
Activation Reaction ◽  
Botulinum Type ◽  
Carbohydrate Fermentation ◽  
Different Strains ◽  
Soil Extract Agar

Five strains of Clostridium botulinum type G of human origin, from Switzerland, were compared with two strains isolated from soil in Argentina. The Swiss and Argentine strains are the only type G strains isolated to date. Characteristics compared were toxigenicity, sporulation, proteolysis and carbohydrate fermentation. High toxin titers were produced in trypticase-peptone-glucose-yeast extract broth incubated anaerobically at 30°C for 10 d. Sporulation occurred in three strains incubated anaerobically on soil extract agar at 35°C for 15 d. Different concentrations of soil extract in the medium promoted sporulation of different strains. Toxins of the Swiss and Argentine strains showed identical patterns for trypsin activation, reaction to A-F antitoxin and neutralization by antitoxin prepared from strain 89G. All seven strains showed delayed proteolytic activity but failed to ferment any of the sugars tested.

scholarly journals Characterisation of the thermostable protease AprX in strains of Pseudomonas fluorescens and impact on the shelf-life of dairy products: preliminary results

2016 ◽  
Vol 5 (4) ◽  
Author(s):  
Nadia Andrea Andreani ◽  
Lisa Carraro ◽  
Luca Fasolato ◽  
Stefania Balzan ◽  
Rosaria Lucchini ◽  
...  
Keyword(s):  
Shelf Life ◽  
Pseudomonas Fluorescens ◽  
Proteolytic Activity ◽  
Dairy Products ◽  
Trinitrobenzenesulfonic Acid ◽  
Predominant Role ◽  
Typing Method ◽  
Milk Samples ◽  
Different Strains ◽  
Reference Strains

Bacterial proteases are involved in food spoilage and shelf-life reduction. Among the bacterial proteases, a predominant role in spoilage of dairy products seems to be played by the thermostable metallo-protease AprX, which is produced by various strains of <em>Pseudomonas fluorescens</em>. Differences in AprX enzyme activity among different strains were highlighted, but the most proteolytic strains were not identified. In this study, the presence of the aprX gene was evaluated in 69 strains isolated from food matrices and 18 reference strains belonging to the P. fluorescens group, which had been previously typed by the multi locus sequence typing method. Subsequently, a subset of reference strains was inoculated in ultra-high temperature milk, and the expression of the <em>aprX</em> gene was evaluated at 22 and 6°C. On the same milk samples, the proteolytic activity was then evaluated through Azocasein and trinitrobenzenesulfonic acid solution assays. Finally, to assess the applicability of the former assay directly on dairy products the proteolityc activity was tested on industrial <em>ricotta</em> samples using the Azocasein assay. These results demonstrate the spread of <em>aprX</em> gene in most strains tested and the applicability of Azocasein assay to monitor the proteolytic activity in dairy products.

Acidification test based on the use of biomass for screening ofLeuconostoc. Application toLn. mesenteroidesstrains isolated from French raw milk cheeses

1995 ◽  
Vol 62 (3) ◽  
pp. 521-527 ◽  
Author(s):  
Yeter Demirci ◽  
Denis Hemme
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Lactococcus Lactis ◽  
Proteolytic Activity ◽  
Raw Milk ◽  
Efficient Tool ◽  
Ph Values ◽  
Different Strains

SummaryUnlike that of other lactic acid bacteria, the growth ofLeuconostocspp. in milk is poor and the resulting acidification cannot be used to distinguish different strains. An acidification test based on the use of high initial numbers (109cfu/ml) has been developed and proved to be an efficient tool for discriminating between 110Leuconostocstrains isolated from French raw milk cheeses. The pH values after 24 h ranged from 6.55 to 4.05 and distinguished four acidification groups. All 34% of the strains that acidified milk to at least pH 5.1, coagulating it and should be considered as Lac+. The differences in rates and degrees of acidification could not be related to the proteolytic activity which was, from all 27 representative strains tested, similar to that ofLactococcus lactisPrt–variants.

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