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.

Single-tube duplex-PCR for specific detection and differentiation of Brucella abortus S19 vaccine strain from other Brucella spp

2018 ◽  
Author(s):  
Aparajita Das ◽  
Bablu Kumar ◽  
Soumendu Chakravarti ◽  
Karam Pal Singh ◽  
Abhishek . ◽  
...  
Keyword(s):  
Vaccine Strain ◽  
Brucella Abortus ◽  
Salmonella Enteritidis ◽  
Pasteurella Multocida ◽  
Clinical Specimen ◽  
Duplex Pcr ◽  
Pcr Assay ◽  
Single Tube ◽  
S19 Vaccine ◽  
Duplex Pcr Assay

A simple single-tube duplex-PCR assay was optimized for rapid and sensitive detection and differentiation of Brucella abortus (B.abortus) S19 vaccine strain from other Brucella spp.(B.abortus 544,B abortus S99,B.melitensis 16M,B.suis).This assay was optimized using two primer pairs that were designed, one targeting genus specific multicopy IS711 and another eryC for the development of the duplex-PCR assay. Specificity of the assay was assessed using DNA templates from various Brucella species (B.abortus, B.melitensis, B.suis) and non Brucella bacteria like Staphylococcus aureus, Proteus vulgaris, Pasteurella multocida, Pseudomonas aeruginosa, Citrobacter freundii, E. coli, Salmonella enteritidis, Campylobacter jejuni and Listeria monocytogenes. The assay was also evaluated on spiked milk samples with known B.abortus cultures. The assay was able to detect up to 2.47 x 103CFU of B. abortus S99 organism in spiked milk sample. The assay was further validated in 53 clinical specimens (aborted foetal stomach content). Results confirm that Single tube duplex-PCR assay was useful for early and rapid detection and differentiation of B. abortus vaccine strain S19 from other Brucella spp in milk as well as in clinical specimen.

Brucella abortus S19 vaccine protects dairy cattle against natural infection with Brucella melitensis

Vaccine ◽  
2016 ◽  
Vol 34 (48) ◽  
pp. 5837-5839 ◽  
Author(s):  
Michael van Straten ◽  
Svetlana Bardenstein ◽  
Gaby Keningswald ◽  
Menachem Banai
Keyword(s):  
Dairy Cattle ◽  
Brucella Abortus ◽  
Brucella Melitensis ◽  
Natural Infection ◽  
S19 Vaccine

scholarly journals Brucella melitensis Biovar 1 and Brucella abortus S19 Vaccine Strain Infections in Milkers Working at Cattle Farms in the Khartoum Area, Sudan

PLoS ONE ◽  
2015 ◽  
Vol 10 (5) ◽  
pp. e0123374 ◽  
Author(s):  
Amira E. F. Osman ◽  
Abdullahi N. Hassan ◽  
Ali E. Ali ◽  
Theresia H. Abdoel ◽  
Henk L. Smits
Keyword(s):  
Vaccine Strain ◽  
Brucella Abortus ◽  
Brucella Melitensis ◽  
Cattle Farms ◽  
S19 Vaccine

scholarly journals The Brucella abortus Phosphoglycerate Kinase Mutant Is Highly Attenuated and Induces Protection Superior to That of Vaccine Strain 19 in Immunocompromised and Immunocompetent Mice

2010 ◽  
Vol 78 (5) ◽  
pp. 2283-2291 ◽  
Author(s):  
Cyntia G. M. C. Trant ◽  
Thais L. S. Lacerda ◽  
Natalia B. Carvalho ◽  
Vasco Azevedo ◽  
Gracia M. S. Rosinha ◽  
...  
Keyword(s):  
Mutant Strain ◽  
Brucella Abortus ◽  
Deletion Mutant ◽  
Bacterial Pathogen ◽  
Phosphoglycerate Kinase ◽  
Wild Type ◽  
Gene Encoding ◽  
Commercial Strain ◽  
Immunocompetent Mice

ABSTRACT Brucella abortus is a facultative intracellular bacterial pathogen that causes abortion in domestic animals and undulant fever in humans. The mechanism of virulence of Brucella spp. is not yet fully understood. Therefore, it is crucial to identify new molecules that can function as virulence factors to better understand the host-pathogen interplay. Herein, we identified the gene encoding the phosphoglycerate kinase (PGK) of B. abortus strain 2308. To test the role of PGK in Brucella pathogenesis, a pgk deletion mutant was constructed. Replacement of the wild-type pgk by recombination was demonstrated by Southern and Western blot analyses. The B. abortus Δpgk mutant strain exhibited extreme attenuation in bone marrow-derived macrophages and in vivo in BALB/c, C57BL/6, 129/Sv, and interferon regulatory factor-1 knockout (IRF-1 KO) mice. Additionally, at 24 h postinfection the Δpgk mutant was not found within the same endoplasmic reticulum-derived compartment as the wild-type bacteria, but, instead, over 60% of Brucella-containing vacuoles (BCVs) retained the late endosomal/lysosomal marker LAMP1. Furthermore, the B. abortus Δpgk deletion mutant was used as a live vaccine. Challenge experiments revealed that the Δpgk mutant strain induced protective immunity in 129/Sv or IRF-1 KO mice that was superior to the protection conferred by commercial strain 19 or RB51. Finally, the results shown here demonstrated that Brucella PGK is critical for full bacterial virulence and that a Δpgk mutant may serve as a potential vaccine candidate in future studies.

scholarly journals Citrate Synthase Mutants of Agrobacterium Are Attenuated in Virulence and Display Reduced vir Gene Induction

2005 ◽  
Vol 187 (14) ◽  
pp. 4844-4852 ◽  
Author(s):  
Maneewan Suksomtip ◽  
Pu Liu ◽  
Tamara Anderson ◽  
Sumalee Tungpradabkul ◽  
Derek W. Wood ◽  
...  
Keyword(s):  
Growth Rate ◽  
Deletion Mutant ◽  
Citrate Synthase ◽  
Brucella Melitensis ◽  
Gene Induction ◽  
Wild Type ◽  
Fold Reduction ◽  
Induced Tumors ◽  
A Minor ◽  
Similar Growth

ABSTRACT A citrate synthase (CS) deletion mutant of Agrobacterium tumefaciens C58 is highly attenuated in virulence. The identity of the mutant was initially determined from its amino acid sequence, which is 68% identical to Escherichia coli and 77% identical to Brucella melitensis. The mutant lost all CS enzymatic activity, and a cloned CS gene complemented a CS mutation in Sinorhizobium. The CS mutation resulted in a 10-fold reduction in vir gene expression, which likely accounts for the attenuated virulence. When a plasmid containing a constitutive virG [virG(Con)] locus was introduced into this mutant, the level of vir gene induction was restored to nearly wild-type level. Further, the virG(Con)-complemented CS mutant strain induced tumors that were similar in size and number to those induced by the parental strain. The CS mutation resulted in only a minor reduction in growth rate in a glucose-salts medium. Both the CS mutant and the virG(Con)-complemented CS strain displayed similar growth deficiencies in a glucose-salts medium, indicating that the reduced growth rate of the CS mutant could not be responsible for the attenuated virulence. A search of the genome of A. tumefaciens C58 revealed four proteins, encoded on different replicons, with conserved CS motifs. However, only the locus that when mutated resulted in an attenuated phenotype has CS activity. Mutations in the other three loci did not result in attenuated virulence and any loss of CS activity, and none were able to complement the CS mutation in Sinorhizobium. The function of these loci remains unknown.

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

scholarly journals N-3-Hydroxy Dodecanoyl-DL-homoserine Lactone (OH-dDHL) Triggers Apoptosis of Bone Marrow-Derived Macrophages through the ER- and Mitochondria-Mediated Pathways

2021 ◽  
Vol 22 (14) ◽  
pp. 7565
Author(s):  
Kyungho Woo ◽  
Dong Ho Kim ◽  
Man Hwan Oh ◽  
Ho Sung Park ◽  
Chul Hee Choi
Keyword(s):  
Bone Marrow ◽  
Quorum Sensing ◽  
Deletion Mutant ◽  
Transmembrane Protein ◽  
Cell Communication ◽  
Homoserine Lactone ◽  
Host Responses ◽  
Wild Type ◽  
Mutant Strains

Quorum sensing of Acinetobacter nosocomialis for cell-to-cell communication produces N-3-hydroxy dodecanoyl-DL-homoserine lactone (OH-dDHL) by an AnoR/I two-component system. However, OH-dDHL-driven apoptotic mechanisms in hosts have not been clearly defined. Here, we investigated the induction of apoptosis signaling pathways in bone marrow-derived macrophages treated with synthetic OH-dDHL. Moreover, the quorum-sensing system for virulence regulation was evaluated in vivo using wild-type and anoI-deletion mutant strains. OH-dDHL decreased the viability of macrophage and epithelial cells in dose- and time-dependent manners. OH-dDHL induced Ca2+ efflux and caspase-12 activation by ER stress transmembrane protein (IRE1 and ATF6a p50) aggregation and induced mitochondrial dysfunction through reactive oxygen species (ROS) production, which caused cytochrome c to leak. Pretreatment with a pan-caspase inhibitor reduced caspase-3, -8, and -9, which were activated by OH-dDHL. Pro-inflammatory cytokine and paraoxonase-2 (PON2) gene expression were increased by OH-dDHL. We showed that the anoI-deletion mutant strains have less intracellular invasion compared to the wild-type strain, and their virulence, such as colonization and dissemination, was decreased in vivo. Consequently, these findings revealed that OH-dDHL, as a virulence factor, contributes to bacterial infection and survival as well as the modification of host responses in the early stages of infection.

scholarly journals Borrelia burgdorferi Lacking BBK32, a Fibronectin-Binding Protein, Retains Full Pathogenicity

2006 ◽  
Vol 74 (6) ◽  
pp. 3305-3313 ◽  
Author(s):  
Xin Li ◽  
Xianzhong Liu ◽  
Deborah S. Beck ◽  
Fred S. Kantor ◽  
Erol Fikrig
Keyword(s):  
Life Cycle ◽  
Borrelia Burgdorferi ◽  
Deletion Mutant ◽  
Binding Protein ◽  
Kanamycin Resistance ◽  
Binding Activity ◽  
Mammalian Host ◽  
Wild Type ◽  
Fibronectin Binding Protein ◽  
Fibronectin Binding

ABSTRACT BBK32, a fibronectin-binding protein of Borrelia burgdorferi, is one of many surface lipoproteins that are differentially expressed by the Lyme disease spirochete at various stages of its life cycle. The level of BBK32 expression in B. burgdorferi is highest during infection of the mammalian host and lowest in flat ticks. This temporal expression profile, along with its fibronectin-binding activity, strongly suggests that BBK32 may play an important role in Lyme pathogenesis in the host. To test this hypothesis, we constructed an isogenic BBK32 deletion mutant from wild-type B. burgdorferi B31 by replacing the BBK32 gene with a kanamycin resistance cassette through homologous recombination. We examined both the wild-type strain and the BBK32 deletion mutant extensively in the experimental mouse-tick model of the Borrelia life cycle. Our data indicated that B. burgdorferi lacking BBK32 retained full pathogenicity in mice, regardless of whether mice were infected artificially by syringe inoculation or naturally by tick bite. The loss of BBK32 expression in the mutant had no adverse effect on spirochete acquisition (mouse-to-tick) and transmission (tick-to-mouse) processes. These results suggest that additional B. burgdorferi proteins can complement the function of BBK32, fibronectin binding or otherwise, during the natural spirochete life cycle.

scholarly journals exrB: amalB-linked gene inEscherichia coliB involved in sensitivity to radiation and filament formation

1974 ◽  
Vol 23 (2) ◽  
pp. 175-184 ◽  
Author(s):  
Joseph Greenberg ◽  
Leonard J. Berends ◽  
John Donch ◽  
Michael H. L. Green
Keyword(s):  
Escherichia Coli ◽  
Normal Growth ◽  
Filament Formation ◽  
Wild Type ◽  
Sensitive Mutant ◽  
Γ Radiation ◽  
Linked Gene ◽  
Derivatives Of

SUMMARYPAM 26, a radiation-sensitive mutant ofEscherichia colistrain B, is described. Its properties are attributable to a mutation in a gene,exrB, which is cotransducible withmalB. It differs fromuvrA(alsomalB-linked) derivatives of strain B in being sensitive to 1-methyl-3-nitro-1-nitroso-guanidine and γ-radiation, and in being able to reactivate UV-irradiated phage T3. It differs fromexrA(alsomalB-linked) derivatives of strain B in forming filaments during the course of normal growth as well as after irradiation. WhenexrBwas transduced into a K12 (lon+) strain, filaments did not form spontaneously. Three-point transductions established the order of markers asmet A malB exrB. Based on an analysis of the frequency of wild-type recombinants in a reciprocal transduction betweenexrAandexrBstrains, it was inferred that they are not isogenic and that the order of markers ismalB exrA exrB.

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.

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