In vitro and in vivo phenotypes resulting from deletion of the high temperature requirement A (htrA) gene from the bovine vaccine strain Brucella abortus S19

1996 ◽  
Vol 49 (3-4) ◽  
pp. 197-207 ◽  
Author(s):  
Gregory T. Robertson ◽  
Philip H. Elzer ◽  
R.Martin Roop
Keyword(s):  
High Temperature ◽  
Vaccine Strain ◽  
Brucella Abortus ◽  
Temperature Requirement

Behaviour of a high-temperature-requirement A (HtrA) deletion mutant of Brucella abortus in goats

1996 ◽  
Vol 60 (1) ◽  
pp. 48-50 ◽  
Author(s):  
P.H Elzer ◽  
S.D Hagius ◽  
G.T Robertson ◽  
R.W Phillips ◽  
J.V Walker ◽  
...  
Keyword(s):  
High Temperature ◽  
Brucella Abortus ◽  
Deletion Mutant ◽  
Temperature Requirement

Microspore development inBrassica napus and the effect of high temperature on division in vivo and in vitro

PROTOPLASMA ◽  
1993 ◽  
Vol 172 (2-4) ◽  
pp. 154-165 ◽  
Author(s):  
Cheryl A. Telmer ◽  
W. Newcomb ◽  
Daina H. Simmonds
Keyword(s):  
High Temperature ◽  
Microspore Development

scholarly journals Mice Lacking Components of Adaptive Immunity Show Increased Brucella abortus virB Mutant Colonization

2007 ◽  
Vol 75 (6) ◽  
pp. 2965-2973 ◽  
Author(s):  
Hortensia García Rolán ◽  
Renée M. Tsolis
Keyword(s):  
Adaptive Immunity ◽  
Brucella Abortus ◽  
Mononuclear Phagocytes ◽  
Wild Type ◽  
Adaptive Immune ◽  
Type Iv ◽  
Absolute Requirement ◽  
The Relationship

ABSTRACT The Brucella abortus type IV secretion system (T4SS), encoded by the virB genes, is essential for survival in mononuclear phagocytes in vitro. In the mouse model, a B. abortus virB mutant was initially able to colonize the spleen at the level of the wild type for approximately 3 to 5 days, which coincided with the development of adaptive immunity. To investigate the relationship between survival in macrophages cultivated in vitro and persistence in tissues in vivo, we tested the ability of mutant mice lacking components of adaptive immunity to eliminate the virB mutant from the spleen during a mixed infection with the B. abortus wild type. Ifng −/− or β 2 m −/− mice were able to clear the virB mutant to the same degree as control mice. However, spleens of Rag1 −/− mice and Igh6 −/− mice were more highly colonized by the virB mutant than control mice after 14 to 21 days, suggesting that, in these mice, there is not an absolute requirement for the T4SS to mediate persistence of B. abortus in the spleen. Macrophages isolated from Igh6 −/− mice killed the virB mutant to the same extent as macrophages from control mice, showing that the reduced ability of these mice to clear the virB mutant from the spleen does not correlate with diminished macrophage function in vitro. These results show that in the murine model host, the T4SS is required for persistence beyond 3 to 5 days after infection and suggest that the T4SS may contribute to evasion of adaptive immune mechanisms by B. abortus.

scholarly journals virB-Mediated Survival of Brucella abortus in Mice and Macrophages Is Independent of a Functional Inducible Nitric Oxide Synthase or NADPH Oxidase in Macrophages

2002 ◽  
Vol 70 (9) ◽  
pp. 4826-4832 ◽  
Author(s):  
Yao-Hui Sun ◽  
Andreas B. den Hartigh ◽  
Renato de Lima Santos ◽  
L. Garry Adams ◽  
Renée M. Tsolis
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Nadph Oxidase ◽  
Inducible Nitric Oxide Synthase ◽  
Brucella Abortus ◽  
In Vivo Models ◽  
Oxide Synthase ◽  
Inducible Nitric Oxide

ABSTRACT The Brucella abortus virB locus is required for establishing chronic infection in the mouse. Using in vitro and in vivo models, we investigated whether virB is involved in evasion of the bactericidal activity of NADPH oxidase and the inducible nitric oxide synthase (iNOS) in macrophages. Elimination of NADPH oxidase or iNOS activity in macrophages in vitro increased recovery of wild-type B. abortus but not recovery of a virB mutant. In mice lacking either NADPH oxidase or iNOS, however, B. abortus infected and persisted to the same extent as it did in congenic C57BL/6 mice up until 60 days postinfection, suggesting that these host defense mechanisms are not critical for limiting bacterial growth in the mouse. A virB mutant did not exhibit increased survival in either of the knockout mouse strains, indicating that this locus does not contribute to evasion of nitrosative or oxidative killing mechanisms in vivo.

scholarly journals Characterization of Specific Immune Responses of Mice Inoculated with Recombinant Vaccinia Virus Expressing an 18-Kilodalton Outer Membrane Protein of Brucella abortus

2000 ◽  
Vol 7 (1) ◽  
pp. 114-118 ◽  
Author(s):  
Ramesh Vemulapalli ◽  
Silvio Cravero ◽  
Christine L. Calvert ◽  
Thomas E. Toth ◽  
Nammalwar Sriranganathan ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Vaccinia Virus ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Brucella Abortus ◽  
Virulent Strain ◽  
Shuttle Vector ◽  
Protein Fusion

ABSTRACT Using the shuttle vector pMCO2 and the vaccinia virus wild-type WR strain, we constructed a recombinant virus expressing an 18-kDa outer membrane protein of Brucella abortus. BALB/c mice inoculated with this virus produced 18-kDa protein-specific antibodies, mostly of immunoglobulin G2a isotype, and in vitro stimulation of splenocytes from these mice with purified maltose binding protein–18-kDa protein fusion resulted in lymphocyte proliferation and gamma interferon production. However, these mice were not protected against a challenge with the virulent strain B. abortus2308. Disruption of the 18-kDa protein's gene in vaccine strainB. abortus RB51 did not affect either the strain's protective capabilities or its in vivo attenuation characteristics. These observations suggest that the 18-kDa protein plays no role in protective immunity.

In vitro and in vivo characterization of smooth small colony variants of Brucella abortus S19

2006 ◽  
Vol 8 (2) ◽  
pp. 363-371 ◽  
Author(s):  
J. Jacob ◽  
G.M. Hort ◽  
P. Overhoff ◽  
M.E.A. Mielke
Keyword(s):  
Brucella Abortus ◽  
Small Colony Variants ◽  
Small Colony ◽  
In Vivo Characterization

Study on Assessment of High Temperature and Humidity in Working Environment on Human Health

2012 ◽  
Vol 610-613 ◽  
pp. 739-742 ◽  
Author(s):  
Yu Ping Sun ◽  
Neng Zhu
Keyword(s):  
High Temperature ◽  
Energy Metabolism ◽  
Human Health ◽  
Physiological Responses ◽  
Working Environment ◽  
Heat Diffusion ◽  
Metabolic Heat ◽  
Temperature And Humidity

In this study, a series of references on human physiology and psychology response to hot and humid environments were analyzed. On basis of the thermo metabolism system, energy metabolism system, cardiovascular system and respiratory system, impact mechanism of high temperature and humidity on human health was presented. The results indicate that the high temperature and humidity in working environment have significant impact on human health. The high temperature and humidity cause the reducing of temperature difference in vitro and in vivo, the difficult of metabolic heat diffusion, the significant increasing of energy metabolism and oxygen consumption, heart failure, hypoxia and other physiological responses.

scholarly journals WrpA Is an Atypical Flavodoxin Family Protein under Regulatory Control of the Brucella abortus General Stress Response System

2016 ◽  
Vol 198 (8) ◽  
pp. 1281-1293 ◽  
Author(s):  
Julien Herrou ◽  
Daniel M. Czyż ◽  
Jonathan W. Willett ◽  
Hye-Sook Kim ◽  
Gekleng Chhor ◽  
...  
Keyword(s):  
Stress Response ◽  
Mouse Model ◽  
Binding Site ◽  
Brucella Abortus ◽  
Chronic Infection ◽  
Content Type ◽  
General Stress Response ◽  
General Stress

ABSTRACTThe general stress response (GSR) system of the intracellular pathogenBrucella abortuscontrols the transcription of approximately 100 genes in response to a range of stress cues. The core genetic regulatory components of the GSR are required forB. abortussurvival under nonoptimal growth conditionsin vitroand for maintenance of chronic infection in anin vivomouse model. The functions of the majority of the genes in the GSR transcriptional regulon remain undefined.bab1_1070is among the most highly regulated genes in this regulon: its transcription is activated 20- to 30-fold by the GSR system under oxidative conditionsin vitro. We have solved crystal structures of Bab1_1070 and demonstrate that it forms a homotetrameric complex that resembles those of WrbA-type NADH:quinone oxidoreductases, which are members of the flavodoxin protein family. However,B. abortusWrbA-relatedprotein (WrpA) does not bind flavin cofactors with a high affinity and does not function as an NADH:quinone oxidoreductasein vitro. Soaking crystals with flavin mononucleotide (FMN) revealed a likely low-affinity binding site adjacent to the canonical WrbA flavin binding site. Deletion ofwrpA(ΔwrpA) does not compromise cell survival under acute oxidative stressin vitroor attenuate infection in cell-based or mouse models. However, a ΔwrpAstrain does elicit increased splenomegaly in a mouse model, suggesting that WrpA modulatesB. abortusinteraction with its mammalian host. Despite high structural homology with canonical WrbA proteins, we propose thatB. abortusWrpA represents a functionally distinct member of the diverse flavodoxin family.IMPORTANCEBrucella abortusis an etiological agent of brucellosis, which is among the most common zoonotic diseases worldwide. The general stress response (GSR) regulatory system ofB. abortuscontrols the transcription of approximately 100 genes and is required for maintenance of chronic infection in a murine model; the majority of GSR-regulated genes remain uncharacterized. We presentin vitroandin vivofunctional and structural analyses of WrpA, whose expression is strongly induced by GSR under oxidative conditions. Though WrpA is structurally related to NADH:quinone oxidoreductases, it does not bind redox cofactors in solution, nor does it exhibit oxidoreductase activityin vitro. However, WrpA does affect spleen inflammation in a murine infection model. Our data provide evidence that WrpA forms a new functional class of WrbA/flavodoxin family proteins.

scholarly journals Whole Ovine Ovaries as a Model for Human: Perfusion with CryoprotectantsIn VivoandIn Vitro

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Vladimir Isachenko ◽  
Gohar Rahimi ◽  
Maria Dattena ◽  
Peter Mallmann ◽  
Saltanat Baikoshkarova ◽  
...  
Keyword(s):  
High Temperature ◽  
Calf Serum ◽  
Surgical Removal ◽  
Vascular Pedicle ◽  
Perfusion Medium ◽  
Bovine Calf Serum ◽  
Freezing Medium ◽  
Human Ovaries

These experiments were performed to test the perfusion of ovine as a model for human ovaries by cryoprotectantsin vivoat high temperature when the permeability of capillaries is high and when blood is insensibly replaced by the solution of cryoprotectants. By our hypothetical supposition, ovaries could be saturated by cryoprotectants before their surgical removal. The objective was to examine the effectiveness of perfusion of ovine ovaries with vascular pediclein vivoandin vitro.Arteria ovaricawas cannuled and ovaries were perfused by Leibovitz L-15 medium + 100 IU/mL heparin + 5% bovine calf serum + 6% dimethyl sulfoxide + 6% ethylene glycol + 0.15 M sucrose + Indian inkin vivoandin vitro. In the first and second cycle of experiments, ovaries (n=13andn=23) were perfusedin vivoandin vitro, respectively, during 60 min with the rate of perfusion 50 mL/h (0.8 mL/min). It was established within vivoperfusion that only about 10% of ovarian tissues were perfused due to an appearance of multiple anastomoses when the perfusion medium goes fromarteria ovaricatoarteria uterinawithout inflow into the ovaries. It was concluded thatin vitroperfusion of ovine intact ovaries with vascular pedicle by freezing medium is more effective than this manipulation performedin vivo.

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