Typhoid fever as cellular microbiological model

Andrade, Dahir Ramos de; Júnior, Dahir Ramos de Andrade

doi:10.1590/s0036-46652003000400002

Cited by 11 publications

(7 citation statements)

References 39 publications

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“…It is well known that the invasion of Salmonella activates caspase-1 and triggers the release of the pro-inflammatory cytokines interleukin (IL)-18 and IL-1β by macrophages [ 47 , 48 ]. Additionally, TNF-α, as a main pro-inflammatory cytokine with antibacterial activity against Salmonella can be produced by macrophages [ 49 ]. To explore whether acetylation of PhoP affects the inflammation activation in macrophage, cell supernatants were collected after S .…”

Section: Resultsmentioning

confidence: 99%

Acetylation of Lysine 201 Inhibits the DNA-Binding Ability of PhoP to Regulate Salmonella Virulence

et al. 2016

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The two-component system PhoP-PhoQ is highly conserved in bacteria and regulates virulence in response to various signals for bacteria within the mammalian host. Here, we demonstrate that PhoP could be acetylated by Pat and deacetylated by deacetylase CobB enzymatically in vitro and in vivo in Salmonella Typhimurium. Specifically, the conserved lysine residue 201(K201) in winged helix–turn–helix motif at C-terminal DNA-binding domain of PhoP could be acetylated, and its acetylation level decreases dramatically when bacteria encounter low magnesium, acid stress or phagocytosis of macrophages. PhoP has a decreased acetylation and increased DNA-binding ability in the deletion mutant of pat. However, acetylation of K201 does not counteract PhoP phosphorylation, which is essential for PhoP activity. In addition, acetylation of K201 (mimicked by glutamine substitute) in S. Typhimurium causes significantly attenuated intestinal inflammation as well as systemic infection in mouse model, suggesting that deacetylation of PhoP K201 is essential for Salmonella pathogenesis. Therefore, we propose that the reversible acetylation of PhoP K201 may ensure Salmonella promptly respond to different stresses in host cells. These findings suggest that reversible lysine acetylation in the DNA-binding domain, as a novel regulatory mechanism of gene expression, is involved in bacterial virulence across microorganisms.

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Section: Resultsmentioning

confidence: 99%

Acetylation of Lysine 201 Inhibits the DNA-Binding Ability of PhoP to Regulate Salmonella Virulence

et al. 2016

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“…Outros estudos em cães da raça Beagle demonstraram que a ivermectina não afetou a espermatogênese, fertilidade e performance na reprodução destes animais, podendo ser utilizada em cães reprodutores (ANDRADE & SANTARÉM, 2002). SCHNIEDER et al (1996) utilizaram a doramectina na dose 1 mg/kg subcutânea em cinco fêmeas gestantes nos dias 40 e 55 de gestação, não detectando qualquer alteração ou reação adversa nas fêmeas e nos filhotes durante a gestação e após o nascimento.…”

Section: Resultsunclassified

Quatro Protocolos De Tratamento Da Sarna Sarcóptica Em Coelhos

Martins

2018

MSJ

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Esse estudo objetivou avaliar o efeito de quatro princípios ativos no tratamento da sarna sarcóptica causada pelo ácaro Sarcoptes scabiei var. cuniculi em coelhos. Distribuíram-se, aleatoriamente, 20 coelhos adultos, machos e fêmeas, com sinais clínicos de sarna e diagnóstico laboratorial positivo, em quatro grupos de cinco. No grupo I fez-se uso tópico de monossulfureto de tetraetiltiuram 5%, diluído em 1:1, durante uma semana; nos grupos II e III aplicou-se, respectivamente, ivermectina e doramectina 1%, via subcutânea, em dose única de 1000µg/kg; no grupo IV fez-se uso tópico, de 4g/animal/dia de enxofre 98% (pó) diluído em óleo vegetal, durante uma semana. Após 30 dias, realizaram-se exames laboratoriais, não constatando o agente etiológico. Esse resultado, associado ao desaparecimento dos sinais clínicos, permite afirmar que houve 100% de recuperação nos quatro grupos. Não foram observados abortos ou redução da libido nos machos. Apesar de eficientes, os tratamentos dos grupos I e IV, provocaram inquietude, irritabilidade cutânea e foram de difícil operacionalização. Verificou-se, nos grupos II e III, o manejo rápido, de fácil execução, além disso, os animais não demonstraram sinais de intranquilidade ou estresse. Os princípios ativos ivermectina e doramectina 1% apresentaram eficácia superior no tratamento da sarna sarcóptica em coelhos.

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“…This does not follow the pattern observed in actual human infection where the bacterial counts in the blood decrease with increasing duration of illness [52], such that by the fourth week, the bacterial concentration is 82% less than it was in the first week. Although death typically occurs after the third week of disease, in cases that survive, the fever declines in the fourth week without antibiotic therapy [56].…”

Section: Discussionmentioning

confidence: 99%

Within-host mathematical modelling of the incubation period ofSalmonellaTyphi

et al. 2019

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Mechanistic mathematical models are often employed to understand the dynamics of infectious diseases within a population or within a host. They provide estimates that may not be otherwise available. We have developed a within-host mathematical model in order to understand how the pathophysiology of Salmonella Typhi contributes to its incubation period. The model describes the process of infection from ingestion to the onset of clinical illness using a set of ordinary differential equations. The model was parametrized using estimated values from human and mouse experimental studies and the incubation period was estimated as 9.6 days. A sensitivity analysis was also conducted to identify the parameters that most affect the derived incubation period. The migration of bacteria to the caecal lymph node was observed as a major bottle neck for infection. The sensitivity analysis indicated the growth rate of bacteria in late phase systemic infection and the net population of bacteria in the colon as parameters that most influence the incubation period. We have shown in this study how mathematical models aid in the understanding of biological processes and can be used in estimating parameters of infectious diseases.

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Typhoid fever as cellular microbiological model

Cited by 11 publications

References 39 publications

Acetylation of Lysine 201 Inhibits the DNA-Binding Ability of PhoP to Regulate Salmonella Virulence

Acetylation of Lysine 201 Inhibits the DNA-Binding Ability of PhoP to Regulate Salmonella Virulence

Quatro Protocolos De Tratamento Da Sarna Sarcóptica Em Coelhos

Within-host mathematical modelling of the incubation period ofSalmonellaTyphi

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