Insights into irr and rirA gene regulation on the virulence of Brucella melitensis M5-90

2020 ◽  
Vol 66 (5) ◽  
pp. 351-358
Author(s):  
Huan Zhang ◽  
Benben Wang ◽  
Wenxing Wu ◽  
Xiaoyu Deng ◽  
Zhiran Shao ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Brucella Abortus ◽  
Vaccine Candidate ◽  
Brucella Melitensis ◽  
Response Regulator ◽  
Iron Acquisition ◽  
Brucella Species ◽  
Splenic Index ◽  
Number Of Bacteria ◽  
Growth Ability

Iron is a fundamental element required by most organisms, including Brucella. Several researchers have suggested that the iron response regulator (irr) and rhizobial iron regulator (rirA) genes regulate iron acquisition by Brucella abortus, influencing heme synthesis by and virulence of this pathogen. However, little is known about another Brucella species, Brucella melitensis. In this research, we successfully constructed two mutants: M5-90Δirr and M5-90ΔrirA. The adhesion, invasion, and intracellular survivability of these two mutants were evaluated in RAW264.7 cells infected with 1 × 106 CFU of M5-90Δirr, M5-90ΔrirA, or M5-90. We also tested the sensitivity of cells to hydrogen peroxide and their ability to grow. In addition, the virulence of these two mutants was evaluated in BALB/c mice. The results showed that the ability of these two mutants to invade and adhere inside the murine macrophages RAW264.7 was attenuated but their ability to replicate intracellularly was strengthened, enhancing the resistance to hydrogen peroxide. The M5-90Δirr mutant showed stronger growth ability than the parental strain under iron-limiting conditions. No differences were observed in the number of bacteria in spleen between M5-90 and M5-90Δirr at 7 or 15 days postinfection. However, the number of M5-90ΔrirA in spleen reduced significantly at 15 days postinfection. The splenic index of the M5-90Δirr group is evidently lower than that of M5-90. This is the first report that irr and rirA genes of B. melitensis are associated not only with virulence but also with growth ability. Together, our data suggest that M5-90Δirr is a promising Brucella vaccine candidate.

scholarly journals Multiplex PCR Assay for the Identification and Differentiation of all Brucella Species and the Vaccine Strains Brucella abortus S19 and RB51 and Brucella melitensis Rev1

2006 ◽  
Vol 52 (4) ◽  
pp. 779-781 ◽  
Author(s):  
David García-Yoldi ◽  
Clara M Marín ◽  
María J de Miguel ◽  
Pilar M Muñoz ◽  
José L Vizmanos ◽  
...  
Keyword(s):  
Multiplex Pcr ◽  
Brucella Abortus ◽  
Brucella Melitensis ◽  
Brucella Species ◽  
Pcr Assay ◽  
Multiplex Pcr Assay

scholarly journals Thermostable Cross-Protective Subunit Vaccine against Brucella Species

2014 ◽  
Vol 21 (12) ◽  
pp. 1681-1688 ◽  
Author(s):  
John W. Cherwonogrodzky ◽  
Nicole D. Barabé ◽  
Michelle L. Grigat ◽  
William E. Lee ◽  
Robert T. Poirier ◽  
...  
Keyword(s):  
Subunit Vaccine ◽  
Vaccine Candidate ◽  
Single Injection ◽  
Brucella Melitensis ◽  
Bacterial Colonization ◽  
Brucella Species ◽  
Promising Candidate ◽  
Content Type ◽  
A Subunit ◽  
Multiple Strains

ABSTRACTA subunit vaccine candidate was produced fromBrucella suis145 (biovar 4; expressing both the A antigen ofBrucella abortusand the M antigen ofBrucella melitensis). The preparation consisted mostly of polysaccharide (PS; >90% [wt/wt]; both cell-associated PS and exo-PS were combined) and a small amount of protein (1 to 3%) with no apparent nucleic acids. Vaccinated mice were protected (these had a statistically significant reduction in bacterial colonization compared to that of unvaccinated controls) when challenged with representative strains of threeBrucellaspecies most pathogenic for humans, i.e.,B. abortus,B. melitensis, andB. suis. As little as 1 ng of the vaccine, without added adjuvant, protected mice againstB. suis145 infection (5 × 105CFU), and a single injection of 1 μg of this subunit vaccine protected mice fromB. suis145 challenge for at least 14 months. A single immunization induced a serum IgG response toBrucellaantigens that remained elevated for up to 9 weeks. The use of heat (i.e., boiling-water bath, autoclaving) in the vaccine preparation showed that it was thermostable. This method also ensured safety and security. The vaccine produced was immunogenic and highly protective against multiple strains ofBrucellaand represents a promising candidate for further evaluation.

Identification, geographic distribution and risk factors of Brucella abortus and Brucella melitensis infection in cattle in Algeria

2021 ◽  
Vol 254 ◽  
pp. 109004
Author(s):  
Nedjma Lounes ◽  
Falk Melzer ◽  
Ashraf E. Sayour ◽  
Hassiba Tali Maamar ◽  
Kheira Rahal ◽  
...  
Keyword(s):  
Risk Factors ◽  
Geographic Distribution ◽  
Brucella Abortus ◽  
Brucella Melitensis

Improvement of the attenuated mutant strain of Brucella melitensis Rev1 as a potential vaccine candidate

Biologia ◽  
2021 ◽  
Author(s):  
Elham Mehdizadeh Marzenaki ◽  
Ali Reza Saeedinia ◽  
Mehdi Zeinoddini ◽  
Ali Asghar Deldar
Keyword(s):  
Mutant Strain ◽  
Vaccine Candidate ◽  
Brucella Melitensis ◽  
Potential Vaccine Candidate ◽  
Potential Vaccine

scholarly journals Construction of Brucella melitensis ghost as a putative vaccine candidate against re-emerging disease – Brucellosis

2020 ◽  
Vol 101 ◽  
pp. 475-476
Author(s):  
B. Sumathi ◽  
B. Veeregowda ◽  
S. Byregowda ◽  
D. Rathnamma ◽  
S. Rajeswari ◽  
...  
Keyword(s):  
Vaccine Candidate ◽  
Brucella Melitensis ◽  
Emerging Disease

scholarly journals Deletion of znuA Virulence Factor Attenuates Brucella abortus and Confers Protection against Wild-Type Challenge

2006 ◽  
Vol 74 (7) ◽  
pp. 3874-3879 ◽  
Author(s):  
Xinghong Yang ◽  
Todd Becker ◽  
Nancy Walters ◽  
David W. Pascual
Keyword(s):  
Brucella Abortus ◽  
Deletion Mutant ◽  
Pasteurella Multocida ◽  
Brucella Melitensis ◽  
Normal Growth ◽  
Wild Type ◽  
Minimal Growth ◽  
M Genome ◽  
S19 Vaccine ◽  
Knockout Mutation

ABSTRACT znuA is known to be an important factor for survival and normal growth under low Zn2+ concentrations for Escherichia coli, Haemophilus spp., Neisseria gonorrhoeae, and Pasteurella multocida. We hypothesized that the znuA gene present in Brucella melitensis 16 M would be similar to znuA in B. abortus and questioned whether it may also be an important factor for growth and virulence of Brucella abortus. Using the B. melitensis 16 M genome sequence, primers were designed to construct a B. abortus deletion mutant. A znuA knockout mutation in B. abortus 2308 (ΔznuA) was constructed and found to be lethal in low-Zn2+ medium. When used to infect macrophages, ΔznuA B. abortus showed minimal growth. Further study with ΔznuA B. abortus showed that its virulence in BALB/c mice was attenuated, and most of the bacteria were cleared from the spleen within 8 weeks. Protection studies confirmed the ΔznuA mutant as a potential live vaccine, since protection against wild-type B. abortus 2308 challenge was as effective as that obtained with the RB51 or S19 vaccine strain.

scholarly journals Production of the Siderophore 2,3-Dihydroxybenzoic Acid Is Required for Wild-Type Growth of Brucella abortus in the Presence of Erythritol under Low-Iron Conditions In Vitro

2003 ◽  
Vol 71 (5) ◽  
pp. 2927-2832 ◽  
Author(s):  
Bryan H. Bellaire ◽  
Philip H. Elzer ◽  
Cynthia L. Baldwin ◽  
R. Martin Roop
Keyword(s):  
Brucella Abortus ◽  
Reproductive Tract ◽  
Iron Acquisition ◽  
Energy Sources ◽  
Growth Defect ◽  
Wild Type ◽  
Dihydroxybenzoic Acid ◽  
Experimental Findings ◽  
The Relationship

ABSTRACT Production of the siderophore 2,3-dihyroxybenzoic acid (2,3-DHBA) is required for the wild-type virulence of Brucella abortus in cattle. A possible explanation for this requirement was uncovered when it was determined that a B. abortus dhbC mutant (BHB1) defective in 2,3-DHBA production displays marked growth restriction in comparison to its parent strain, B. abortus 2308, when cultured in the presence of erythritol under low-iron conditions. This phenotype is not displayed when these strains are cultured under low-iron conditions in the presence of other readily utilizable carbon and energy sources. The addition of either exogenous 2,3-DHBA or FeCl3 relieves this growth defect, suggesting that the inability of the B. abortus dhbC mutant to display wild-type growth in the presence of erythritol under iron-limiting conditions is due to a defect in iron acquisition. Restoring 2,3-DHBA production to the B. abortus dhbC mutant by genetic complementation abolished the erythritol-specific growth defect exhibited by this strain in low-iron medium, verifying the relationship between 2,3-DHBA production and efficient growth in the presence of erythritol under low-iron conditions. The positive correlation between 2,3-DHBA production and growth in the presence of erythritol was further substantiated by the observation that the addition of erythritol to low-iron cultures of B. abortus 2308 stimulated the production of 2,3-DHBA by increasing the transcription of the dhbCEBA operon. Correspondingly, the level of exogenous iron needed to repress dhbCEBA expression in B. abortus 2308 was also greater when this strain was cultured in the presence of erythritol than that required when it was cultured in the presence of any of the other readily utilizable carbon and energy sources tested. The tissues of the bovine reproductive tract are rich in erythritol during the latter stages of pregnancy, and the ability to metabolize erythritol is thought to be important to the virulence of B. abortus in pregnant ruminants. Consequently, the experimental findings presented here offer a plausible explanation for the attenuation of the B. abortus 2,3-DHBA-deficient mutant BHB1 in pregnant ruminants.

scholarly journals Candida albicans Response Regulator Gene SSK1 Regulates a Subset of Genes Whose Functions Are Associated with Cell Wall Biosynthesis and Adaptation to Oxidative Stress

2003 ◽  
Vol 2 (5) ◽  
pp. 1018-1024 ◽  
Author(s):  
Neeraj Chauhan ◽  
Diane Inglis ◽  
Elvira Roman ◽  
Jesus Pla ◽  
Dongmei Li ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Signal Transduction ◽  
Hydrogen Peroxide ◽  
Cell Wall ◽  
Response Regulator ◽  
Cell Wall Biosynthesis ◽  
Regulator Protein ◽  
Two Component ◽  
Response Regulator Protein ◽  
Mutant Cells

ABSTRACT Ssk1p of Candida albicans is a putative response regulator protein of the Hog1 two-component signal transduction system. In Saccharomyces cerevisiae, the phosphorylation state of Ssk1p determines whether genes that promote the adaptation of cells to osmotic stress are activated. We have previously shown that C. albicans SSK1 does not complement the ssk1 mutant of S. cerevisiae and that the ssk1 mutant of C. albicans is not sensitive to sorbitol. In this study, we show that the C. albicans ssk1 mutant is sensitive to several oxidants, including hydrogen peroxide, t-butyl hydroperoxide, menadione, and potassium superoxide when each is incorporated in yeast extract-peptone-dextrose (YPD) agar medium. We used DNA microarrays to identify genes whose regulation is affected by the ssk1 mutation. RNA from mutant cells (strain CSSK21) grown in YPD medium for 3 h at 30°C was reverse transcribed and then compared with similarly prepared RNA from wild-type cells (CAF2). We observed seven genes from mutant cells that were consistently up regulated (three-fold or greater compared to CAF2). In S. cerevisiae, three (AHP1, HSP12, and PYC2) of the seven genes that were up regulated provide cells with an adaptation function in response to oxidative stress; another gene (GPH1) is regulated under stress conditions by Hog1p. Three other genes that are up regulated encode a cell surface protein (FLO1), a mannosyl transferase (MNN4-4), and a putative two-component histidine kinase (CHK1) that regulates cell wall biosynthesis in C. albicans. Of the down-regulated genes, ALS1 is a known cell adhesin in C. albicans. Verification of the microarray data was obtained by reverse transcription-PCR for HSP12, AHP1, CHK1, PYC2, GPH1, ALS1, MNN4-4, and FLO1. To further determine the function of Ssk1p in the Hog1p signal transduction pathway in C. albicans, we used Western blot analysis to measure phosphorylation of Hog1p in the ssk1 mutant of C. albicans when grown under either osmotic or oxidative stress. We observed that Hog1p was phosphorylated in the ssk1 mutant of C. albicans when grown in a hyperosmotic medium but was not phosphorylated in the ssk1 mutant when the latter was grown in the presence of hydrogen peroxide. These data indicate that C. albicans utilizes the Ssk1p response regulator protein to adapt cells to oxidative stress, while its role in the adaptation to osmotic stress is less certain. Further, SSK1 appears to have a regulatory function in some aspects of cell wall biosynthesis. Thus, the functions of C. albicans SSK1 differ from those of S. cerevisiae SSK1.

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