scholarly journals Virulence gene expression, proteins secreted and morphological alterations of Vibrio parahaemolyticus and Vibrio alginolyticus in response to long-term starvation in seawater

2011 ◽  
Vol 5 (7) ◽  
pp. 792-801 ◽  
Author(s):  
Ben Abdallah Fethi ◽  
Ellafi Ali ◽  
Lagha Rihab ◽  
Kallel Heacute la ◽  
Bakhrouf Amina
Keyword(s):  
Gene Expression ◽  
Vibrio Parahaemolyticus ◽  
Virulence Gene ◽  
Vibrio Alginolyticus ◽  
Morphological Alterations ◽  
Virulence Gene Expression

scholarly journals Bile Acid-Induced Virulence Gene Expression of Vibrio parahaemolyticus Reveals a Novel Therapeutic Potential for Bile Acid Sequestrants

PLoS ONE ◽  
2010 ◽  
Vol 5 (10) ◽  
pp. e13365 ◽  
Author(s):  
Kazuyoshi Gotoh ◽  
Toshio Kodama ◽  
Hirotaka Hiyoshi ◽  
Kaori Izutsu ◽  
Kwon-Sam Park ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bile Acid ◽  
Vibrio Parahaemolyticus ◽  
Therapeutic Potential ◽  
Virulence Gene ◽  
Virulence Gene Expression ◽  
Bile Acid Sequestrants ◽  
Novel Therapeutic

scholarly journals Thymidine-Dependent Staphylococcus aureus Small-Colony Variants Are Associated with Extensive Alterations in Regulator and Virulence Gene Expression Profiles

2005 ◽  
Vol 73 (7) ◽  
pp. 4119-4126 ◽  
Author(s):  
Barbara C. Kahl ◽  
Gunnar Belling ◽  
Petra Becker ◽  
Indranil Chatterjee ◽  
Katrin Wardecki ◽  
...  
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Virulence Gene ◽  
Northern Analysis ◽  
Normal Strain ◽  
Transcription Analysis ◽  
Small Colony Variants ◽  
Virulence Gene Expression ◽  
Small Colony

ABSTRACT Chronic airway infection is a hallmark of cystic fibrosis (CF) and many CF patients are infected persistently by Staphylococcus aureus. Thymidine-dependent trimethoprim-sulfamethoxazole (SXT)-resistant S. aureus small-colony variants (SCVs), often in combination with isogenic normal S. aureus phenotypes, are highly prevalent and persistent in airway secretions of CF patients due to long-term SXT therapy (B. Kahl, M. Herrmann, A. S. Everding, H. G. Koch, K. Becker, E. Harms, R. A. Proctor, and G. Peters, J. Infect. Dis. 177:1023-1029, 1998). In this report, SCVs were compared to normal S. aureus by transcription analysis of important regulator (sigB, sarA, and agr) and virulence (α-hemolysin, hla, and protein A, spa) genes. Growth curve analyses revealed longer doubling times and lower final densities for SCVs than for normal strains. sigB activity was measured by transcription analysis of the sigB target gene asp23. For nearly all SCVs, expression of all regulators was decreased as assessed by asp23 reverse transcription-PCR for sigB and Northern analysis for sarA and agr. These results are in agreement with diminished hla signals in all SCVs and increased spa signals in 5 of 10 SCVs compared to the isogenic normal S. aureus. Both supplementation of SCVs with thymidine and activation of the agr quorum-sensing system by the supernatant of the isogenic normal strain reversed transcription to almost normal levels. In conclusion, multiple changes in growth characteristics and in regulator and virulence gene expression render SCVs less virulent and allow them to survive in the hostile environment present in the airways of CF patients, thereby illustrating adaptation of the bacteria during long-term persistence.

scholarly journals Morphological Alterations and Virulence Gene Expression of Listeria Monocytogenes Cells in Response to Gamma Irradiation Treatments

2021 ◽  
Vol 04 (5) ◽  
pp. 01-09
Author(s):  
Hamouda Elabed
Keyword(s):  
Gene Expression ◽  
Fatty Acid ◽  
Listeria Monocytogenes ◽  
Gamma Irradiation ◽  
Membrane Lipids ◽  
Virulence Gene ◽  
Morphological Alteration ◽  
Morphological Alterations ◽  
Virulence Gene Expression ◽  
Wide Range

Gamma irradiation is one of the most popular ray treatments in food industry. It's used to control micro-organisms proliferation in a wide range of products however the response of bacteria to low doses is still unknown. In this study we mainly focus on morphological alteration and virulence gene expression in Listeria monocytogenes after gamma irradiation treatments. The atomic force micrographs (AFM) showed that 0.5 kGy dose has no effect on the membrane morphology of L. monocytogenes. However, after 0.7 kGy treatment, the cells lost their typical shape and smooth membrane and 1 kGy dose was totally destructive. Moreover, membrane fatty acid composition was analyzed by the chromatographic method after different gamma doses. Significant modifications on fatty acids composition were detected in the irradiated strain showing a novo synthesis of membrane lipids: C12:0; C14:0; C15:0; C16:0 and C18:0. In addition, we reported an increase of the saturated fatty acid, essential for membrane adaptation under stress conditions. The expression levels of three virulence genes (hlyA, fri and prfA) were studied in the same conditions using real-time PCR technique. The analysis revealed that both prfA and fri genes were up-regulated after gamma treatment. The induction of prfA, which is a regulator gene, may affect the expression other genes controlling the adaptive form in the treated strain. This study open prospects for further researches to explain the regulatory mechanisms of the adaptive response in Listeria monocytogenes when exposed to sublethal irradiation-stress.

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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