Cell-Free Preparations of Lactobacillus acidophilus Strain La-5 and Bifidobacterium longum Strain NCC2705 Affect Virulence Gene Expression in Campylobacter jejuni

2013 ◽  
Vol 76 (10) ◽  
pp. 1740-1746 ◽  
Author(s):  
A. MUNDI ◽  
V. DELCENSERIE ◽  
M. AMIRI-JAMI ◽  
S. MOORHEAD ◽  
M. W. GRIFFITHS
Keyword(s):  
Campylobacter Jejuni ◽  
Lactobacillus Acidophilus ◽  
Diarrheal Disease ◽  
Bifidobacterium Longum ◽  
Virulence Gene ◽  
Active Role ◽  
Inhibitory Effect ◽  
Virulence Gene Expression ◽  
Luxs Mutant ◽  
Methyl Cycle

Campylobacter spp. are among the most commonly reported bacterial causes of acute diarrheal disease in humans worldwide. Potential virulence factors include motility, chemotaxis, colonization ability, adhesion to intestinal cells, invasion and epithelial translocation, intracellular survival, and formation of toxins. Probiotic Lactobacillus and Bifidobacterium strains are known to have an inhibitory effect against the growth of various foodborne pathogens. The objective of this study was to investigate the effect of Lactobacillus acidophilus strain La-5 and Bifidobacterium longum strain NCC2705 cell-free spent media (CFSM) on the expression of virulence genes (cadF, cdtB, flaA, and ciaB) of Campylobacter jejuni strain 81-176 and a luxS mutant, using real-time PCR. Our results demonstrated that the CFSM of both probiotic strains were able to down-regulate the expression of ciaB (ratio of −2.80 and −5.51, respectively) and flaA (ratio of −7.00 and −5.13, respectively) in the wild-type Campylobacter strain. In the luxS mutant, where the activated methyl cycle is disrupted, only the ciaB gene (ratio −7.21) was repressed in the presence of La-5 CFSM. A supplementation of homocysteine to restore the disrupted cycle was able to partially reestablish the probiotic effect of both strains. luxS and the activated methyl cycle might play an active role in the modulation of virulence of C. jejuni by probiotic extracts.

scholarly journals Effects of resveratrol on cariogenic virulence properties of Streptococcus mutans

2020 ◽  
Author(s):  
Jinheng Li ◽  
Tiantian Wu ◽  
Weiwei Peng ◽  
yaqin zhu
Keyword(s):  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Acid Production ◽  
Virulence Gene ◽  
Acid Tolerance ◽  
Extracellular Polysaccharide ◽  
Inhibitory Effect ◽  
Water Soluble ◽  
Virulence Gene Expression ◽  
Virulence Properties

Abstract Background: Streptococcus mutans is the principal etiological agent of human dental caries. The major virulence factors of S. mutans are acid production, acid tolerance, extracellular polysaccharide (EPS) synthesis and biofilm formation. The aim of this study is to evaluate the effect of resveratrol, a natural compound, on virulence properties of S. mutans . Results: Resveratrol at sub-MIC levels significantly decreased acid production and acid tolerance, inhibited synthesis of water-soluble polysaccharide and water-insoluble polysaccharide, compromised biofilm formation. Related virulence gene expression ( ldh, relA, gtfC, comDE ) was down-regulated with increasing concentrations of resveratrol. Conclusions : Resveratrol has an inhibitory effect on S. mutans cariogenic virulence properties and it represents a promising anticariogenic agent. Keywords : resveratrol, Streptococcus mutans , acidogenicity, aciduricity, extracellular polysaccharide, biofilm

scholarly journals Inhibitory effect of goat and cow milk fermented by Bifidobacterium longum on Serratia marcescens and Campylobacter jejuni

2011 ◽  
Vol 24 (No. 4) ◽  
pp. 164-171 ◽  
Author(s):  
H. Pavlović ◽  
J. Hardi ◽  
V. Slačanac ◽  
M. Halt ◽  
D. Kocevski
Keyword(s):  
Serratia Marcescens ◽  
Campylobacter Jejuni ◽  
Bifidobacterium Longum ◽  
Goat Milk ◽  
Fermented Milk ◽  
Inhibitory Effect ◽  
Cow Milk ◽  
Fermentation Time ◽  
Ph Values ◽  
Fermentation Parameters

This study was performed to determine the influence of fermented goat and cow milk produced by the use of Bifidobacterium longum Bb-46 on pathogenic Serratia marcescens and Campylobacter jejuni strains. The correlation between the inhibitory effect and some fermentation parameters (the number of viable probiotic cells and pH of fermented milk) was also determined. Bifidobacterium longum counts and pH values were also measured in milk samples during fermentation. The results showed that the inhibitory effect of Bifidobacterium longum Bb-46 fermented goat milk on Serratia marcescens increased with the fermentation time. The highest inhibitory effect of fermented cow milk occurred in the middle course of fermentation. Statistically significant correlation between the inhibition degree of Serratia marcescens growth and pH values of fermented goat milk was noted as opposed to the correlation between the inhibition degree of Serratia marcescens growth and pH values of fermented cow milk which was not statistically significant. All samples of goat and cow fermented milk exhibited inhibitory effects on the growth of Campylobacter jejuni.  

scholarly journals Culture of Campylobacter jejuni with Sodium Deoxycholate Induces Virulence Gene Expression

2008 ◽  
Vol 190 (7) ◽  
pp. 2286-2297 ◽  
Author(s):  
Preeti Malik-Kale ◽  
Craig T. Parker ◽  
Michael E. Konkel
Keyword(s):  
Campylobacter Jejuni ◽  
Cell Invasion ◽  
Virulence Gene ◽  
Sodium Deoxycholate ◽  
Culture Conditions ◽  
Metabolic Labeling ◽  
Virulence Gene Expression ◽  
Reverse Transcription Pcr ◽  
Virulence Potential

ABSTRACT Campylobacter jejuni, a spiral-shaped gram-negative bacterium, is a leading bacterial cause of human food-borne illness. Acute disease is associated with C. jejuni invasion of the intestinal epithelium. Further, maximal host cell invasion requires the secretion of proteins termed Campylobacter invasion antigens (Cia). As bile acids are known to alter the pathogenic behavior of other gastrointestinal pathogens, we hypothesized that the virulence potential of Campylobacter may be triggered by the bile acid deoxycholate (DOC). In support of this hypothesis, culturing C. jejuni with a physiologically relevant concentration of DOC significantly altered the kinetics of cell invasion, as shown by gentamicin protection assays. In contrast to C. jejuni harvested from Mueller-Hinton (MH) agar plates, C. jejuni harvested from MH agar plates supplemented with DOC secreted the Cia proteins, as judged by metabolic labeling experiments. DOC was also found to induce the expression of the ciaB gene, as determined by β-galactosidase reporter, real-time reverse transcription-PCR, and microarray analyses. Microarray analysis further revealed that DOC induced the expression of virulence genes (ciaB, cmeABC, dccR, and tlyA). In summary, we demonstrated that it is possible to enhance the pathogenic behavior of C. jejuni by modifying the culture conditions. These results provide a foundation for identifying genes expressed by C. jejuni in response to in vivo-like culture conditions.

scholarly journals Conjugated Linoleic Acid Reduces Cholera Toxin ProductionIn VitroandIn Vivoby Inhibiting Vibrio cholerae ToxT Activity

2015 ◽  
Vol 59 (12) ◽  
pp. 7471-7476 ◽  
Author(s):  
Jeffrey H. Withey ◽  
Dhrubajyoti Nag ◽  
Sarah C. Plecha ◽  
Ritam Sinha ◽  
Hemanta Koley
Keyword(s):  
Linoleic Acid ◽  
Cholera Toxin ◽  
Diarrheal Disease ◽  
Treatment Options ◽  
Virulence Gene ◽  
Content Type ◽  
Virulence Gene Expression ◽  
Intravenous Rehydration ◽  
Regulator Protein ◽  
Current Therapies

ABSTRACTThe severe diarrheal disease cholera is endemic in over 50 countries. Current therapies for cholera patients involve oral and/or intravenous rehydration, often combined with the use of antibiotics to shorten the duration and intensity of the disease. However, as antibiotic resistance increases, treatment options will become limited. Linoleic acid has been shown to be a potent negative effector ofV. choleraevirulence that acts on the major virulence transcription regulator protein, ToxT, to inhibit virulence gene expression. ToxT activates transcription of the two major virulence factors required for disease, cholera toxin (CT) and toxin-coregulated pilus (TCP). A conjugated form of linoleic acid (CLA) is currently sold over the counter as a dietary supplement and is generally recognized as safe by the U.S. Food and Drug Administration. This study examined whether CLA could be used as a new therapy to reduce CT production, which, in turn, would decrease disease duration and intensity in cholera patients. CLA could be used in place of traditional antibiotics and would be very unlikely to generate resistance, as it affects only virulence factor production and not bacterial growth or survival.

scholarly journals Effects of resveratrol on cariogenic virulence properties of Streptococcus mutans

2020 ◽  
Author(s):  
Jinheng Li ◽  
Yaqin Zhu ◽  
Tiantian Wu ◽  
Weiwei Peng
Keyword(s):  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Acid Production ◽  
Virulence Gene ◽  
Acid Tolerance ◽  
Extracellular Polysaccharide ◽  
Inhibitory Effect ◽  
Water Soluble ◽  
Virulence Gene Expression ◽  
Virulence Properties

Abstract Background: Streptococcus mutans is the principal etiological agent of human dental caries. The major virulence factors of S. mutans are acid production, acid tolerance, extracellular polysaccharide (EPS) synthesis and biofilm formation. The aim of this study is to evaluate the effect of resveratrol, a natural compound, on virulence properties of S. mutans . Methods: The effect of resveratrol on acidogenicity was investigated by pH drop and lactate dehydrogenase (LDH) assay, on aciduricity through survival rate at pH 5.0 and F-ATPase assay, on EPS synthesis (including water-soluble polysaccharide and water-insoluble polysaccharide) by quantitative measurement, on biofilm formation by crystal violet assay and structure observation. The expression of related virulence genes was also detected . Results: Resveratrol at sub-MIC levels can significantly decrease acid production, acid tolerance, EPS synthesis and biofilm formation. Related virulence gene expression ( ldh , relA , gtfC , comDE ) was down-regulated with increasing concentrations of resveratrol. Conclusion: Resveratrol has an inhibitory effect on S. mutans cariogenic virulence properties and it represents a promising anticariogenic agent .

scholarly journals Effects of resveratrol on cariogenic virulence properties of Streptococcus mutans

2019 ◽  
Author(s):  
Jinheng Li ◽  
Tiantian Wu ◽  
Weiwei Peng ◽  
Yaqin Zhu
Keyword(s):  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Acid Production ◽  
Virulence Gene ◽  
Acid Tolerance ◽  
Extracellular Polysaccharide ◽  
Inhibitory Effect ◽  
Water Soluble ◽  
Virulence Gene Expression ◽  
Virulence Properties

Abstract Background: Streptococcus mutans is the principal etiological agent of human dental caries. The major virulence factors of S. mutans are acid production, acid tolerance, extracellular polysaccharide (EPS) synthesis and biofilm formation. The aim of this study is to evaluate the effect of resveratrol, a natural compound, on virulence properties of S. mutans . Methods: The effect of resveratrol on acidogenicity was investigated by pH drop and lactate dehydrogenase (LDH) assay, on aciduricity through survival rate at pH 5.0 and F-ATPase assay, on EPS synthesis (including water-soluble polysaccharide and water-insoluble polysaccharide) by quantitative measurement, on biofilm formation by crystal violet assay and structure observation. The expression of related virulence genes was also detected . Results: Resveratrol at sub-MIC levels can significantly decrease acid production, acid tolerance, EPS synthesis and biofilm formation. Related virulence gene expression ( ldh , relA , gtfC , comDE ) was down-regulated with increasing concentrations of resveratrol. Conclusion: Resveratrol has an inhibitory effect on S. mutans cariogenic virulence properties and it represents a promising anticariogenic agent .

Vibrio harveyi virulence gene expression in vitro and in vivo during infection in black tiger shrimp Penaeus monodon

2020 ◽  
Vol 139 ◽  
pp. 153-160
Author(s):  
S Peeralil ◽  
TC Joseph ◽  
V Murugadas ◽  
PG Akhilnath ◽  
VN Sreejith ◽  
...  
Keyword(s):  
Gene Expression ◽  
Virulence Genes ◽  
Vibrio Harveyi ◽  
Penaeus Monodon ◽  
Challenge Test ◽  
Virulence Gene ◽  
Economic Losses ◽  
Virulence Gene Expression

Luminescent Vibrio harveyi is common in sea and estuarine waters. It produces several virulence factors and negatively affects larval penaeid shrimp in hatcheries, resulting in severe economic losses to shrimp aquaculture. Although V. harveyi is an important pathogen of shrimp, its pathogenicity mechanisms have yet to be completely elucidated. In the present study, isolates of V. harveyi were isolated and characterized from diseased Penaeus monodon postlarvae from hatcheries in Kerala, India, from September to December 2016. All 23 tested isolates were positive for lipase, phospholipase, caseinase, gelatinase and chitinase activity, and 3 of the isolates (MFB32, MFB71 and MFB68) showed potential for significant biofilm formation. Based on the presence of virulence genes, the isolates of V. harveyi were grouped into 6 genotypes, predominated by vhpA+ flaB+ ser+ vhh1- luxR+ vopD- vcrD+ vscN-. One isolate from each genotype was randomly selected for in vivo virulence experiments, and the LD50 ranged from 1.7 ± 0.5 × 103 to 4.1 ± 0.1 × 105 CFU ml-1. The expression of genes during the infection in postlarvae was high in 2 of the isolates (MFB12 and MFB32), consistent with the result of the challenge test. However, in MFB19, even though all genes tested were present, their expression level was very low and likely contributed to its lack of virulence. Because of the significant variation in gene expression, the presence of virulence genes alone cannot be used as a marker for pathogenicity of V. harveyi.

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