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1.
Emerg Infect Dis ; 28(10): 2125-2126, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36007931

RESUMO

Epidemic typhus, caused by Rickettsia prowazekii bacteria and transmitted through body lice (Pediculus humanus corporis), was a major public health threat in Eastern Europe as a consequence of World War II. In 2022, war and the resulting population displacement in Ukraine risks the return of this serious disease.


Assuntos
Infestações por Piolhos , Pediculus , Rickettsia prowazekii , Tifo Epidêmico Transmitido por Piolhos , Animais , Humanos , Pediculus/microbiologia , Tifo Epidêmico Transmitido por Piolhos/epidemiologia , Tifo Epidêmico Transmitido por Piolhos/história , Tifo Epidêmico Transmitido por Piolhos/microbiologia , Ucrânia/epidemiologia
2.
PLoS Negl Trop Dis ; 16(5): e0010354, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35639778

RESUMO

Murine typhus, which is caused by Rickettsia typhi, has a wide range of clinical manifestations. It has a low mortality rate but may result in meningoencephalitis and interstitial pneumonia in severe cases. Comparisons of complete genome sequences of R. typhi isolates from North Carolina, USA (Wilmington), Myanmar (B9991PP), and Thailand (TH1527) identified only 26 single nucleotide polymorphism (SNP) and 7 insertion-deletion (INDEL) sites in these highly syntenic genomes. Assays were developed to further define the distribution of these variant sites among 15 additional isolates of R. typhi with different histories from Asia, the USA, and Africa. Mismatch amplification mutation assays (MAMA) were validated for 22 SNP sites, while the 7 INDEL sites were analyzed directly on agarose gels. Six SNP types, 9 INDEL types, 11 total types were identified among these 18 isolates. Replicate DNA samples as well as comparisons of isolates with different passage and source histories gave consistent genetic typing profiles. Comparison of the SNP and INDEL markers to R. typhi's nearest neighbor Rickettsia prowazekii demonstrated that the majority of the SNPs represent intra-species variation that arose post divergence of these two species while several INDEL sites also exhibited intraspecies variability among the R. prowazekii genomes that have been completely sequenced. The assays for the presence of these SNP and INDEL sites, particularly the latter, comprise a low technology gel method for consistently distinguishing R. typhi and R. prowazekii as well as for differentiating genetic types of R. typhi.


Assuntos
Rickettsia prowazekii , Rickettsia , Tifo Endêmico Transmitido por Pulgas , Animais , Camundongos , Rickettsia/genética , Rickettsia prowazekii/genética , Rickettsia typhi/genética , Análise de Sequência de DNA , Tailândia
3.
J Microbiol Methods ; 176: 106034, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32805367

RESUMO

The authors applied a new methodological approach based not only on the study of IgM/IgG to Rickettsia prowazekii in sera, but also on the estimation of the avidity index of specific IgG. The data allowed the authors to draw new conclusions about the 1998 epidemic typhus outbreak in Russia.


Assuntos
Anticorpos Antibacterianos/sangue , Surtos de Doenças , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Rickettsia prowazekii/imunologia , Tifo Epidêmico Transmitido por Piolhos , Humanos , Estudos Retrospectivos , Federação Russa/epidemiologia , Tifo Epidêmico Transmitido por Piolhos/sangue , Tifo Epidêmico Transmitido por Piolhos/epidemiologia , Tifo Epidêmico Transmitido por Piolhos/imunologia
4.
Biochem J ; 477(2): 491-508, 2020 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-31922183

RESUMO

Acyl carrier proteins (ACPs) are small helical proteins found in all kingdoms of life, primarily involved in fatty acid and polyketide biosynthesis. In eukaryotes, ACPs are part of the fatty acid synthase (FAS) complex, where they act as flexible tethers for the growing lipid chain, enabling access to the distinct active sites in FAS. In the type II synthesis systems found in bacteria and plastids, these proteins exist as monomers and perform various processes, from being a donor for synthesis of various products such as endotoxins, to supplying acyl chains for lipid A and lipoic acid FAS (quorum sensing), but also as signaling molecules, in bioluminescence and activation of toxins. The essential and diverse nature of their functions makes ACP an attractive target for antimicrobial drug discovery. Here, we report the structure, dynamics and evolution of ACPs from three human pathogens: Borrelia burgdorferi, Brucella melitensis and Rickettsia prowazekii, which could facilitate the discovery of new inhibitors of ACP function in pathogenic bacteria.


Assuntos
Proteína de Transporte de Acila/ultraestrutura , Infecções Bacterianas/microbiologia , Ácido Graxo Sintases/ultraestrutura , Conformação Proteica , Proteína de Transporte de Acila/química , Proteína de Transporte de Acila/genética , Sequência de Aminoácidos/genética , Infecções Bacterianas/tratamento farmacológico , Borrelia burgdorferi/química , Borrelia burgdorferi/patogenicidade , Borrelia burgdorferi/ultraestrutura , Brucella melitensis/química , Brucella melitensis/patogenicidade , Brucella melitensis/ultraestrutura , Domínio Catalítico , Ácido Graxo Sintases/química , Ácido Graxo Sintases/genética , Interações Hospedeiro-Patógeno/genética , Humanos , Lipídeo A/química , Lipídeo A/genética , Simulação de Dinâmica Molecular , Complexos Multienzimáticos , Ressonância Magnética Nuclear Biomolecular , Ligação Proteica/genética , Percepção de Quorum/genética , Rickettsia prowazekii/química , Rickettsia prowazekii/patogenicidade , Rickettsia prowazekii/ultraestrutura
5.
Bioorg Med Chem Lett ; 28(8): 1376-1380, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29551481

RESUMO

Methionine aminopeptidase (MetAP) is a dinuclear metalloprotease responsible for the cleavage of methionine initiator residues from nascent proteins. MetAP activity is necessary for bacterial proliferation and is therefore a projected novel antibacterial target. A compound library consisting of 294 members containing metal-binding functional groups was screened against Rickettsia prowazekii MetAP to determine potential inhibitory motifs. The compounds were first screened against the target at a concentration of 10 µM and potential hits were determined to be those exhibiting greater than 50% inhibition of enzymatic activity. These hit compounds were then rescreened against the target in 8-point dose-response curves and 11 compounds were found to inhibit enzymatic activity with IC50 values of less than 10 µM. Finally, compounds (1-5) were docked against RpMetAP with AutoDock to determine potential binding mechanisms and the results were compared with crystal structures deposited within the PDB.


Assuntos
Antibacterianos/química , Metaloproteases/antagonistas & inibidores , Metionil Aminopeptidases/antagonistas & inibidores , Inibidores de Proteases/química , Bibliotecas de Moléculas Pequenas/química , Domínio Catalítico , Ensaios Enzimáticos , Metaloproteases/química , Metionil Aminopeptidases/química , Simulação de Acoplamento Molecular , Rickettsia prowazekii/enzimologia
6.
Acta Trop ; 178: 115-118, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29126839

RESUMO

Pediculus humanus capitis is a small ectoparasitic insect that has lived and feds on human beings for thousands of years. Molecular techniques have been used for Pediculus species identification and evolutionary, phylogenic, and ecological studies. A total of 23 adults of P. h. capitis were collected in Gaziantep, located in southeast Turkey, and DNA was isolated from all P. h. capitis using DNA extraction kit. All DNA samples were screened for investigate of Ricettsia prowazekii, Bartonella quintana and Borrelia recurrentis with real-time polymerase chain reaction. In addition, we investigated genetic variation in DNA samples of Pediculus humanus capitis using the cytochrome oxidase I genetic DNA sequence. We found 4 (17.4%) Ricettsia prowazekii and 3 (13.1%) Bartonella quintana in DNA samples of Pediculus humanus capitis, while we did not find any Bartonella recurrentis in any of the DNA samples. We demonstrated 1.8% genetic variations in DNA samples of Pediculus humanus capitis with Bartonella quintana. The phylogenetic tree based on the cytochrome oxidase I gene revealed that P. h. capitis in southeast Turkey are classified into two clades (clade A, clade B) and Bartonella quintana was found in only clade B. However, we did not find any genetic variations in other DNA samples in this region. The genetic variations may be related to P. h.capitis vector of Bartonella quintana has found in this study. In addition, this study was shown that P. h. capitis do transmit Rickettsia prowazekii and Bartonella quintana to people, epidemic typhus and trench fever may emergence in Gaziantep southeast of Turkey in the future.


Assuntos
Saúde Pública , Febre das Trincheiras/epidemiologia , Tifo Epidêmico Transmitido por Piolhos/epidemiologia , Adulto , Animais , Bartonella quintana/isolamento & purificação , Humanos , Pediculus/microbiologia , Reação em Cadeia da Polimerase em Tempo Real , Rickettsia prowazekii/isolamento & purificação , Risco , Febre das Trincheiras/genética , Turquia/epidemiologia , Tifo Epidêmico Transmitido por Piolhos/genética
7.
Ticks Tick Borne Dis ; 8(6): 827-836, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28709615

RESUMO

Natural pathogen transmission of Rickettsia prowazekii, the etiologic agent of epidemic typhus, to humans is associated with arthropods, including human body lice, ticks, and ectoparasites of eastern flying squirrel. Recently, we have documented the presence of small RNAs in Rickettsia species and expression of R. prowazekii sRNAs during infection of cultured human microvascular endothelial cells (HMECs), which represent the primary target cells during human infections. Bacterial noncoding transcripts are now well established as critical post-transcriptional regulators of virulence and adaptation mechanisms in varying host environments. Despite their importance, little is known about the expression profile and regulatory activities of R. prowazekii sRNAs (Rp_sRs) in different host cells encountered as part of the natural life-cycle. To investigate the sRNA expression profile of R. prowazekii during infection of arthropod host cells, we employed an approach combining in vitro infection, bioinformatics, RNA sequencing, and PCR-based quantitation. Global analysis of R. prowazekii transcriptome by strand-specific RNA sequencing enabled us to identify 67 cis-acting (antisense) and 26 trans-acting (intergenic) Rp_sRs expressed during the infection of Amblyomma americanum (AAE2) cells. Comparative evaluation of expression during R. prowazekii infection of HMECs and AAE2 cells by quantitative RT-PCR demonstrated significantly higher expression of four selected Rp_sRs in tick AAE2 cells. Examination of the coding transcriptome revealed differential up-regulation of >150 rickettsial genes in either HMECs or AAE2 cells and yielded evidence for host cell-dependent utilization of alternative transcription start sites by 18 rickettsial genes. Our results thus suggest noticeable differences in the expression of both Rp_sRs as well as the coding transcriptome and the exploitation of multiple transcription initiation sites for select genes during the infection of human endothelium and tick vector cells as the host and yield new insights into rickettsial virulence and transmission mechanisms.


Assuntos
Vetores Aracnídeos/microbiologia , Regulação Bacteriana da Expressão Gênica , Ixodes/microbiologia , RNA Bacteriano/genética , Pequeno RNA não Traduzido/genética , Rickettsia prowazekii/genética , Transcriptoma , Animais , Perfilação da Expressão Gênica , Interações Hospedeiro-Patógeno , Humanos , Rickettsia prowazekii/metabolismo , Análise de Sequência de RNA , Doenças Transmitidas por Carrapatos/transmissão
8.
Am J Trop Med Hyg ; 96(5): 1088-1093, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28500797

RESUMO

AbstractFlea-borne (murine) typhus is a global rickettsiosis caused by Rickettsia typhi. Although flea-borne typhus is no longer nationally notifiable, cases are reported for surveillance purposes in a few U.S. states. The infection is typically self-limiting, but may be severe or life-threatening in some patients. We performed a retrospective review of confirmed or probable cases of fatal flea-borne typhus reported to the Texas Department of State Health Services during 1985-2015. When available, medical charts were also examined. Eleven cases of fatal flea-borne typhus were identified. The median patient age was 62 years (range, 36-84 years) and 8 (73%) were male. Patients presented most commonly with fever (100%), nausea and vomiting (55%), and rash (55%). Respiratory (55%) and neurologic (45%) manifestations were also identified frequently. Laboratory abnormalities included thrombocytopenia (82%) and elevated hepatic transaminases (63%). Flea or animal contact before illness onset was frequently reported (55%). The median time from hospitalization to administration of a tetracycline-class drug was 4 days (range, 0-5 days). The median time from symptom onset to death was 14 days (range, 1-34 days). Flea-borne typhus can be a life-threatening disease if not treated in a timely manner with appropriate tetracycline-class antibiotics. Flea-borne typhus should be considered in febrile patients with animal or flea exposure and respiratory or neurologic symptoms of unknown etiology.


Assuntos
Rickettsia prowazekii/patogenicidade , Rickettsia typhi/patogenicidade , Tifo Endêmico Transmitido por Pulgas/diagnóstico , Tifo Epidêmico Transmitido por Piolhos/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Antibacterianos/administração & dosagem , Exantema/diagnóstico , Exantema/fisiopatologia , Evolução Fatal , Feminino , Febre/diagnóstico , Febre/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Náusea/diagnóstico , Náusea/fisiopatologia , Rickettsia prowazekii/isolamento & purificação , Rickettsia typhi/isolamento & purificação , Texas , Trombocitopenia/diagnóstico , Trombocitopenia/fisiopatologia , Tempo para o Tratamento , Transaminases/metabolismo , Falha de Tratamento , Tifo Endêmico Transmitido por Pulgas/tratamento farmacológico , Tifo Endêmico Transmitido por Pulgas/microbiologia , Tifo Endêmico Transmitido por Pulgas/patologia , Tifo Epidêmico Transmitido por Piolhos/tratamento farmacológico , Tifo Epidêmico Transmitido por Piolhos/microbiologia , Tifo Epidêmico Transmitido por Piolhos/patologia , Vômito/diagnóstico , Vômito/fisiopatologia
9.
Am J Trop Med Hyg ; 96(5): 1084-1087, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28500808

RESUMO

AbstractRickettsial infections are recognized as important causes of fever throughout southeast Asia. Herein, we determined the seroprevalence to rickettsioses within rural and urban populations of northern Vietnam. Prevalence of individuals with evidence of prior rickettsial infections (IgG positive) was surprisingly low, with 9.14% (83/908) testing positive to the three major rickettsial serogroups thought to circulate in the region. Prevalence of typhus group rickettsiae (TG)-specific antibodies (6.5%, 58/908) was significantly greater than scrub typhus group orientiae (STG)- or spotted fever group rickettsiae (SFG)-specific antibodies (P < 0.05). The majority of TG seropositives were observed among urban rather than rural residents (P < 0.05). In contrast, overall antibody prevalence to STG and SFG were both very low (1.1%, 10/908 for STG; 1.7%, 15/908 for SFG), with no significant differences between rural and urban residents. These results provide data on baseline population characteristics that may help inform development of Rickettsia serological testing criteria in future clinical studies.


Assuntos
Anticorpos Antibacterianos/sangue , Infecções por Rickettsia/epidemiologia , Tifo por Ácaros/epidemiologia , Tifo Epidêmico Transmitido por Piolhos/epidemiologia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Orientia tsutsugamushi/classificação , Orientia tsutsugamushi/isolamento & purificação , Prevalência , Rickettsia/classificação , Rickettsia/isolamento & purificação , Infecções por Rickettsia/sangue , Infecções por Rickettsia/diagnóstico , Rickettsia prowazekii/classificação , Rickettsia prowazekii/isolamento & purificação , População Rural , Tifo por Ácaros/sangue , Tifo por Ácaros/diagnóstico , Estudos Soroepidemiológicos , Sorotipagem , Tifo Epidêmico Transmitido por Piolhos/sangue , Tifo Epidêmico Transmitido por Piolhos/diagnóstico , População Urbana , Vietnã/epidemiologia
10.
Bioorg Med Chem ; 25(3): 813-824, 2017 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-28089350

RESUMO

Methionine aminopeptidase (MetAP) is a class of ubiquitous enzymes essential for the survival of numerous bacterial species. These enzymes are responsible for the cleavage of N-terminal formyl-methionine initiators from nascent proteins to initiate post-translational modifications that are often essential to proper protein function. Thus, inhibition of MetAP activity has been implicated as a novel antibacterial target. We tested this idea in the present study by targeting the MetAP enzyme in the obligate intracellular pathogen Rickettsia prowazekii. We first identified potent RpMetAP inhibitory species by employing an in vitro enzymatic activity assay. The molecular docking program AutoDock was then utilized to compare published crystal structures of inhibited MetAP species to docked poses of RpMetAP. Based on these in silico and in vitro screens, a subset of 17 compounds was tested for inhibition of R. prowazekii growth in a pulmonary vascular endothelial cell (EC) culture infection model system. All compounds were tested over concentration ranges that were determined to be non-toxic to the ECs and 8 of the 17 compounds displayed substantial inhibition of R. prowazekii growth. These data highlight the therapeutic potential for inhibiting RpMetAP as a novel antimicrobial strategy and set the stage for future studies in pre-clinical animal models of infection.


Assuntos
Antibacterianos/farmacologia , Inibidores Enzimáticos/farmacologia , Metionil Aminopeptidases/antagonistas & inibidores , Rickettsia prowazekii/efeitos dos fármacos , Animais , Antibacterianos/síntese química , Antibacterianos/química , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , Células Endoteliais/efeitos dos fármacos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Metionil Aminopeptidases/metabolismo , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Estrutura Molecular , Artéria Pulmonar/efeitos dos fármacos , Ratos , Rickettsia prowazekii/enzimologia , Relação Estrutura-Atividade
11.
Dynamis (Granada) ; 37(2): 489-515, 2017. tab, graf
Artigo em Espanhol | IBECS | ID: ibc-168868

RESUMO

El tifus exantemático padecido de forma epidémica en los años consecutivos a la Guerra Civil fue momento de una peculiar movilización científica en el Instituto y Escuela Nacional de Sanidad que comenzaban su andadura bajo el franquismo, contando con una significativa participación multinacional, desde la Fundación Rockefeller al Instituto Pasteur, que convirtió España en nudo donde se cruzaban las teorías y las prácticas de las escuelas más relevantes en torno a la consecución de una vacuna eficaz. El artículo reconstruye los elementos en dicha movilización y analiza sus resultados. Las carencias informativas del momento, cierta tensión entre los participantes y la rápida evolución de la situación privaron de resultados prácticos inmediatos a la Sanidad española, lo que no puede decirse en lo tocante al recorrido profesional de varios de los científicos funcionarios implicados. La auténtica explotación de resultados de esta experiencia se llevó a cabo en los Estados Unidos años después (AU)


No disponible


Assuntos
Humanos , História do Século XX , Tifo Epidêmico Transmitido por Piolhos/epidemiologia , Infecções por Rickettsia/epidemiologia , Vacinas Antirrickéttsia/história , Rickettsia prowazekii/patogenicidade , Controle de Doenças Transmissíveis/história
12.
Rev. esp. med. prev. salud pública ; 22(3): 37-44, 2017. ilus
Artigo em Espanhol | IBECS | ID: ibc-169185

RESUMO

El tifus epidémico, está causado por Rickettsia Prowazekii, y es transmitido por el piojo del cuerpo. Durante siglos, ha producido epidemias devastadoras, considerándose que esta infección ha causado más muertes que todas las guerras juntas. La primera epidemia de la que existe constancia tuvo lugar durante el cerco de Granada por los Reyes Católicos, en 1489. Desde entonces hasta el siglo XX, ha acompañado en numerosas ocasiones a los ejércitos, habiendo sido la enfermedad decisiva en algunos casos, para el resultado de los conflictos, debido al número de fallecidos que ocasionó. Algunas situaciones concretas, como guerras, campamentos de refugiados, hacinamiento e inadecuadas condiciones higiénicas, favorecen el desarrollo de la enfermedad. El descubrimiento por Charles Nicolle (1856-1936) del vector de transmisión, el piojo del cuerpo, supuso un avance sustancial en el control de la misma y la llegada de los antibióticos hizo posible su curación


Epidemic typhus is caused by Rickettsia prowazekii and it is transmitted through body lice. For centuries, due to devastating epidemics it has caused more casualties than all wars known in humanity. The first epidemic of which we have record, took place during the siege of Granada by the Spanish Catholic King and Queen in 1489. Since then, and up to the 20th. century, typhus has been linked to armies in combat. Given the large number of deaths caused by this disease, its presence has been crucial in the results of certain conflicts. Certain situations favor the development of typhus epidemics such as wars, overcrowding, refugee camps and inadecuate hygienic conditions. The discovery by Charles Nicolle (1856-1936) of the transmission mechanism by body lice, was a substantial step towards controlling the disease. The appearance of antibiotics determined its definite healing


Assuntos
Humanos , Tifo Epidêmico Transmitido por Piolhos/epidemiologia , Rickettsia prowazekii/patogenicidade , Tifo Epidêmico Transmitido por Piolhos/prevenção & controle , Epidemias/história
13.
Microbiol Spectr ; 4(4)2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27726780

RESUMO

Epidemic typhus caused by Rickettsia prowazekii is one of the oldest pestilential diseases of humankind. The disease is transmitted to human beings by the body louse Pediculus humanus corporis and is still considered a major threat by public health authorities, despite the efficacy of antibiotics, because poor sanitary conditions are conducive to louse proliferation. Epidemic typhus has accompanied disasters that impact humanity and has arguably determined the outcome of more wars than have soldiers and generals. The detection, identification, and characterization of microorganisms in ancient remains by paleomicrobiology has permitted the diagnosis of past epidemic typhus outbreaks through the detection of R. prowazekii. Various techniques, including microscopy and immunodetection, can be used in paleomicrobiology, but most of the data have been obtained by using PCR-based molecular techniques on dental pulp samples. Paleomicrobiology enabled the identification of the first outbreak of epidemic typhus in the 18th century in the context of a pan-European great war in the city of Douai, France, and supported the hypothesis that typhus was imported into Europe by Spanish soldiers returning from America. R. prowazekii was also detected in the remains of soldiers of Napoleon's Grand Army in Vilnius, Lithuania, which indicates that Napoleon's soldiers had epidemic typhus. The purpose of this article is to underscore the modern comprehension of clinical epidemic typhus, focus on the historical relationships of the disease, and examine the use of paleomicrobiology in the detection of past epidemic typhus outbreaks.


Assuntos
Surtos de Doenças , Fósseis/microbiologia , Paleopatologia/métodos , Rickettsia prowazekii/isolamento & purificação , Tifo Epidêmico Transmitido por Piolhos/epidemiologia , Tifo Epidêmico Transmitido por Piolhos/história , Animais , Técnicas Bacteriológicas/métodos , Saúde Global , História do Século XVIII , História do Século XIX , História do Século XX , História do Século XXI , Humanos , Pediculus/crescimento & desenvolvimento , Pediculus/microbiologia , Reação em Cadeia da Polimerase/métodos , Rickettsia prowazekii/genética
14.
J Biol Chem ; 291(38): 19962-74, 2016 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-27474738

RESUMO

Rickettsia belong to a family of Gram-negative obligate intracellular infectious bacteria that are the causative agents of typhus and spotted fever. Outer membrane protein B (OmpB) occurs in all rickettsial species, serves as a protective envelope, mediates host cell adhesion and invasion, and is a major immunodominant antigen. OmpBs from virulent strains contain multiple trimethylated lysine residues, whereas the avirulent strain contains mainly monomethyllysine. Two protein-lysine methyltransferases (PKMTs) that catalyze methylation of recombinant OmpB at multiple sites with varying sequences have been identified and overexpressed. PKMT1 catalyzes predominantly monomethylation, whereas PKMT2 catalyzes mainly trimethylation. Rickettsial PKMT1 and PKMT2 are unusual in that their primary substrate appears to be limited to OmpB, and both are capable of methylating multiple lysyl residues with broad sequence specificity. Here we report the crystal structures of PKMT1 from Rickettsia prowazekii and PKMT2 from Rickettsia typhi, both the apo form and in complex with its cofactor S-adenosylmethionine or S-adenosylhomocysteine. The structure of PKMT1 in complex with S-adenosylhomocysteine is solved to a resolution of 1.9 Å. Both enzymes are dimeric with each monomer containing an S-adenosylmethionine binding domain with a core Rossmann fold, a dimerization domain, a middle domain, a C-terminal domain, and a centrally located open cavity. Based on the crystal structures, residues involved in catalysis, cofactor binding, and substrate interactions were examined using site-directed mutagenesis followed by steady state kinetic analysis to ascertain their catalytic functions in solution. Together, our data reveal new structural and mechanistic insights into how rickettsial methyltransferases catalyze OmpB methylation.


Assuntos
Proteínas da Membrana Bacteriana Externa/química , Histona-Lisina N-Metiltransferase/química , Rickettsia prowazekii/química , Rickettsia typhi/química , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Catálise , Cristalografia por Raios X , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Cinética , Domínios Proteicos , Dobramento de Proteína , Rickettsia prowazekii/genética , Rickettsia prowazekii/metabolismo , Rickettsia typhi/genética , Rickettsia typhi/metabolismo
15.
Am J Trop Med Hyg ; 95(2): 452-6, 2016 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-27352876

RESUMO

In August 2012, laboratory tests confirmed a mixed outbreak of epidemic typhus fever and trench fever in a male youth rehabilitation center in western Rwanda. Seventy-six suspected cases and 118 controls were enrolled into an unmatched case-control study to identify risk factors for symptomatic illness during the outbreak. A suspected case was fever or history of fever, from April 2012, in a resident of the rehabilitation center. In total, 199 suspected cases from a population of 1,910 male youth (attack rate = 10.4%) with seven deaths (case fatality rate = 3.5%) were reported. After multivariate analysis, history of seeing lice in clothing (adjusted odds ratio [aOR] = 2.6, 95% confidence interval [CI] = 1.1-5.8), delayed (≥ 2 days) washing of clothing (aOR = 4.0, 95% CI = 1.6-9.6), and delayed (≥ 1 month) washing of beddings (aOR = 4.6, 95% CI = 2.0-11) were associated with illness, whereas having stayed in the rehabilitation camp for ≥ 6 months was protective (aOR = 0.20, 95% CI = 0.10-0.40). Stronger surveillance and improvements in hygiene could prevent future outbreaks.


Assuntos
Bartonella quintana/isolamento & purificação , Surtos de Doenças , Ftirápteros/microbiologia , Rickettsia prowazekii/isolamento & purificação , Febre das Trincheiras/epidemiologia , Tifo Epidêmico Transmitido por Piolhos/epidemiologia , Adolescente , Adulto , Animais , Bartonella quintana/patogenicidade , Estudos de Casos e Controles , Coinfecção , Humanos , Incidência , Masculino , Razão de Chances , Centros de Reabilitação , Rickettsia prowazekii/patogenicidade , Fatores de Risco , Ruanda/epidemiologia , Análise de Sobrevida , Febre das Trincheiras/diagnóstico , Febre das Trincheiras/mortalidade , Febre das Trincheiras/transmissão , Tifo Epidêmico Transmitido por Piolhos/diagnóstico , Tifo Epidêmico Transmitido por Piolhos/mortalidade , Tifo Epidêmico Transmitido por Piolhos/transmissão
16.
PLoS One ; 11(3): e0152365, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27010457

RESUMO

Rickettsia prowazekii, the causative agent of epidemic typhus, is an obligate intracellular bacterium that replicates only within the cytosol of a eukaryotic host cell. Despite the barriers to genetic manipulation that such a life style creates, rickettsial mutants have been generated by transposon insertion as well as by homologous recombination mechanisms. However, progress is hampered by the length of time required to identify and isolate R. prowazekii transformants. To reduce the time required and variability associated with propagation and harvesting of rickettsiae for each transformation experiment, characterized frozen stocks were used to generate electrocompetent rickettsiae. Transformation experiments employing these rickettsiae established that fluorescent rickettsial populations could be identified using a fluorescence activated cell sorter within one week following electroporation. Early detection was improved with increasing amounts of transforming DNA. In addition, we demonstrate that heterogeneous populations of rickettsiae-infected cells can be sorted into distinct sub-populations based on the number of rickettsiae per cell. Together our data suggest the combination of fluorescent reporters and cell sorting represent an important technical advance that will facilitate isolation of distinct R. prowazekii mutants and allow for closer examination of the effects of infection on host cells at various infectious burdens.


Assuntos
Separação Celular/métodos , Rickettsia prowazekii/isolamento & purificação , Animais , Fluorescência , Proteínas de Fluorescência Verde/genética , Camundongos
17.
Artigo em Russo | MEDLINE | ID: mdl-26470431

RESUMO

Materials, that summarize data of original research and scientific literature on epidemiology and problems of persistence during epidemic typhus, whose causative agent (Rickettsia prowazekii) is reactivated in the organism of the previously ill and is manifested as Brill-Zinser disease, are presented. A retrospective analysis was carried out with the data obtained by Russian (All-Union) Centre for Rickettsioses during study of epidemiologic examination maps of 5705 typhus nidi and results of 19 463 blood sera analysis during study of immunologic structure of population in the territories of the former USSR for the period from 1970 to 1992. A decrease of epidemic typhus morbidity and an increase of the fraction of Brill-Zinser disease took place as a result of pediculosis corporis control. In separate territories specific weight of Brill-Zinser disease was 48% in 1952, up to 80% in 1969, and from 1977 all the ill were previously ill. However, during the perestroika period and afterwards, due to a reduction of economic and hygienic living conditions, appearance of refugees, the immune structure regarding typhus began to change. Due to the buildup of the population migration process and the presence of risk groups (refugees, homeless) among population of regions, where local wars are waged, the enhancement of methods of epidemic typhus and Brill-Zinser disease diagnostics and pediculosis corporis eradication is necessary. Study of R. prowazekii by molecular-genetics methods is necessary for complete understanding of its mechanism of persistence.


Assuntos
Rickettsia prowazekii/imunologia , Tifo Epidêmico Transmitido por Piolhos , Humanos , Tifo Epidêmico Transmitido por Piolhos/epidemiologia , Tifo Epidêmico Transmitido por Piolhos/imunologia , Tifo Epidêmico Transmitido por Piolhos/microbiologia , Tifo Epidêmico Transmitido por Piolhos/prevenção & controle
18.
J Struct Biol ; 189(2): 98-104, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25498244

RESUMO

A convenient strategy to interrogate the biology of regulatory proteins is to replace individual domains by an equivalent domain from a related protein of the same species or from an ortholog of another species. It is generally assumed that the overall properties of the native protein are retained in the chimera, and that functional differences reflect only the specific determinants contained in the swapped domains. Here we used this strategy to circumvent the difficulty in obtaining crystals of Rickettsia prowazekii RalF, a bacterial protein that functions as a guanine nucleotide exchange factor for eukaryotic Arf GTPases. A RalF homolog is encoded by Legionella pneumophila, in which a C-terminal capping domain auto-inhibits the catalytic Sec7 domain and localizes the protein to the Legionella-containing vacuole. The crystal structures of domain-swapped chimeras were determined and used to construct a model of Legionella RalF with a RMSD of less than 1Å with the crystal structure, which validated the use of this approach to build a model of Rickettsia RalF. In the Rickettsia RalF model, sequence differences in the capping domain that target it to specific membranes are accommodated by a shift of the entire domain with respect to the Sec7 domain. However, local sequence changes also give rise to an artifactual salt bridge in one of the chimeras, which likely explains why this chimera is recalcitrant to activation. These findings highlight the structural plasticity whereby chimeras can be engineered, but also underline that unpredictable differences can modify their biochemical responses.


Assuntos
Proteínas de Bactérias/química , Fatores de Troca do Nucleotídeo Guanina/química , Rickettsia prowazekii , Clonagem Molecular , Cristalografia por Raios X , Ligação de Hidrogênio , Legionella pneumophila , Modelos Moleculares , Estrutura Secundária de Proteína , Proteínas Recombinantes de Fusão/química
19.
Wien Med Wochenschr ; 165(7-8): 152-63, 2015 Apr.
Artigo em Alemão | MEDLINE | ID: mdl-25448128

RESUMO

After description of the medical institutions and epidemiological situations of the Austro-Hungarian army in World War I the provisions against spotted fever focused on louse control are discussed. The letter specified for the army had to be adjusted for the local populations. 1915 in the k.u.k. military service in Galicia Edmund Weil and Arthur Felix cultivated Proteus strains from urine of soldiers with spotted fever. As sera of such patients agglutinated these bacteria in considerable titers the investigators developed the reliable diagnostic "Weil-Felix-Test" used still today. In the same military area and time Rudolf Weigl invented the anal infection of lice. This enabled him to harvest a great amount of louse intestines containing the spotted fever Rickettsiae in their epithelial cells. Lots with defined numbers of intestines were homogenized, sterilized and used with success as vaccine for medical staff. This sort of vaccine still was used in World War II.


Assuntos
Microbiologia/história , Medicina Militar/história , Rickettsia prowazekii/imunologia , Vacinas Antirrickéttsia/história , Testes Sorológicos/história , Tifo Epidêmico Transmitido por Piolhos/história , Vacinação/história , I Guerra Mundial , Áustria-Hungria , História do Século XX , Humanos , Masculino
20.
PLoS One ; 9(11): e113285, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25412248

RESUMO

Louse borne typhus (also called epidemic typhus) was one of man's major scourges, and epidemics of the disease can be reignited when social, economic, or political systems are disrupted. The fear of a bioterrorist attack using the etiologic agent of typhus, Rickettsia prowazekii, was a reality. An attenuated typhus vaccine, R. prowazekii Madrid E strain, was observed to revert to virulence as demonstrated by isolation of the virulent revertant Evir strain from animals which were inoculated with Madrid E strain. The mechanism of the mutation in R. prowazekii that affects the virulence of the vaccine was not known. We sequenced the genome of the virulent revertant Evir strain and compared its genome sequence with the genome sequences of its parental strain, Madrid E. We found that only a single nucleotide in the entire genome was different between the vaccine strain Madrid E and its virulent revertant strain Evir. The mutation is a single nucleotide insertion in the methyltransferase gene (also known as PR028) in the vaccine strain that inactivated the gene. We also confirmed that the vaccine strain E did not cause fever in guinea pigs and the virulent revertant strain Evir caused fever in guinea pigs. We concluded that a single nucleotide insertion in the methyltransferase gene of R. prowazekii attenuated the R. prowazekii vaccine strain E. This suggested that an irreversible insertion or deletion mutation in the methyl transferase gene of R. prowazekii is required for Madrid E to be considered a safe vaccine.


Assuntos
Proteínas de Bactérias/genética , Proteínas de Choque Térmico , Metiltransferases/genética , Fragmentos de Peptídeos , Rickettsia prowazekii/patogenicidade , Tifo Epidêmico Transmitido por Piolhos/veterinária , Fatores de Virulência/genética , Animais , Análise Mutacional de DNA/métodos , Genoma Bacteriano , Cobaias , Dados de Sequência Molecular , Mutação , Rickettsia prowazekii/enzimologia , Rickettsia prowazekii/genética , Tifo Epidêmico Transmitido por Piolhos/microbiologia , Tifo Epidêmico Transmitido por Piolhos/prevenção & controle , Vacinas Atenuadas/genética , Vacinas Atenuadas/metabolismo
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