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Comparative Study of the Standard Fluorescent Antibody to Membrane Antigen (FAMA) Assay and a Flow Cytometry-Adapted FAMA Assay To Assess Immunity to Varicella-Zoster Virus

LAFER, M. M.; WECKX, L. Y.; MORAES-PINTO, M. I. de; GARRETSON, A.; STEINBERG, S. P.; GERSHON, A. A.; LARUSSA, P. S.
Fonte: AMER SOC MICROBIOLOGY Publicador: AMER SOC MICROBIOLOGY
Tipo: Artigo de Revista Científica
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A flow cytometry-adapted fluorescent antibody to membrane antigen (FAMA) assay to detect IgG antibodies against varicella-zoster virus (VZV) was developed and tested in 62 serum samples, showing 90.32% accuracy obtained from a receiver operating characteristic (ROC) curve with a 0.9125 (95% confidence interval [CI], 0.829 to 1.00) area below the curve compared to the result with standard FAMA.; Brazilian Ministry of Education`s CAPES[0108-08-1]

Enhancement of diagnostic efficiency by a gamma interferon release assay for pulmonary tuberculosis

KANUNFRE, Kelly Aparecida; LEITE, Olavo Henrique Munhoz; LOPES, Max Igor; LITVOC, Marcelo; FERREIRA, Antonio Walter
Fonte: AMER SOC MICROBIOLOGY Publicador: AMER SOC MICROBIOLOGY
Tipo: Artigo de Revista Científica
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This study was designed to examine the use of the QuantiFERON-TB Gold assay as an aid in the diagnosis of active pulmonary tuberculosis (TB) in Brazilian patients. Using the receiver operating characteristic curve, the cutoff was adjusted to >= 0.20 IU/ml. The sensitivity increased to 86%, with 100% specificity. All TB patients with negative sputum smear microscopy and negative culture results were positive using this test.; FAPESP Fundacao de Amparo a Pesquisa do Estado de Sao Paulo[03/08308-2]; LIM-48 Hospital das Clinicas, School of Medicine,University of Sao Paulo HC-FM-USP; CNPq Conselho Nacional de Desenvolvimento Cientifico e Tecnologico

Dissemination of bla(KPC-2) by the Spread of Klebsiella pneumoniae Clonal Complex 258 Clones (ST258, ST11, ST437) and Plasmids (IncFII, IncN, IncL/M) among Enterobacteriaceae Species in Brazil

ANDRADE, Leonardo Neves; CURIAO, Tania; FERREIRA, Joseane Cristina; LONGO, Juliana Mucedola; CLIMACO, Eduardo Carneiro; MARTINEZ, Roberto; BELLISSIMO-RODRIGUES, Fernando; BASILE-FILHO, Anibal; EVARISTO, Marco Antonio; PELOSO, Pedro F. Del; RIBEIRO, Vaness
Fonte: AMER SOC MICROBIOLOGY Publicador: AMER SOC MICROBIOLOGY
Tipo: Artigo de Revista Científica
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This article reports the spread of bla(KPC-2) in the Sao Paulo and Rio de Janeiro states, facilitated by globally spread K. pneumoniae clonal complex 258 (CC258) clones (ST258, ST11, and ST437) and a diversity of plasmids (IncFII, IncN, and IncL/M, two untypeable plasmids carrying Tn4401a or Tn4401b) successfully disseminated among species of the Enterobacteriaceae (Enterobacter cloacae, Serratia marcescens, and Citrobacter freundii). It also constitutes the first description of sequence type 258 (ST258) in Brazil, which was associated with a nosocomial hospital outbreak in Ribeirao Preto city.; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico in Brazil (CNPq)[480848/2008-4]; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico in Brazil (CNPq)[142736/2008-2]; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico in Brazil (CNPq)[201191/2009-1]; European Commission[LSHM-CT-2009-227258 HEALTH-F3-2008-223031]; CIBERESP Network for Biomedical Research in Epidemiology and Public Health (Instituto Carlos III, Ministerio de Ciencia e Innovacion of Spain)[CB06/02/0053]; Instituto Carlos III, Spanish Ministry of Science and Innovation[FI09/00901]

Evaluation of Adult Chronic Chagas` Heart Disease Diagnosis by Molecular and Serological Methods

RAMIREZ, Juan David; GUHL, Felipe; UMEZAWA, Eufrosina Setsu; MORILLO, Carlos A.; ROSAS, Fernando; MARIN-NETO, Jose A.; RESTREPO, Silvia
Fonte: AMER SOC MICROBIOLOGY Publicador: AMER SOC MICROBIOLOGY
Tipo: Artigo de Revista Científica
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Chagas` disease caused by Trypanosoma cruzi is endemic in Latin America. T. cruzi presents heterogeneous populations and comprises two main genetic lineages, named T. cruzi I and T. cruzi II. Diagnosis in the chronic phase is based on conventional serological tests, including indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assay (ELISA), and diagnosis in the acute phase based on parasitological methods, including hemoculture. The objective of this study was to evaluate the diagnostic procedures of Chagas` disease in adult patients in the chronic phase by using a PCR assay and conventional serological tests, including TESA-blot as the gold standard. Samples were obtained from 240 clinical chronic chagasic patients. The sensitivities, compared to that of TESA-blot, were 70% for PCR using the kinetoplast region, 75% for PCR using the nuclear repetitive region, 99% for IIF, and 95% for ELISA. According to the serological tests results, we recommend that researchers assess the reliability and sensitivity of the commercial kit Chagatest ELISA recombinant, version 3.0 (Chagatest Rec v3.0; Wiener Lab, Rosario, Argentina), due to the lack of sensitivity. Based on our analysis, we concluded that PCR cannot be validated as a conventional diagnostic technique for Chagas` disease. These data have been corroborated by low levels of concordance with serology test results. It is recommended that PCR be used only for alternative diagnostic support. Using the nuclear repetitive region of T. cruzi...

DC-SIGN (CD209) gene promoter polymorphisms in a Brazilian population and their association with human T-cell lymphotropic virus type 1 infection

KASHIMA, Simone; RODRIGUES, Evandra Strazza; AZEVEDO, FRochele; CASTELLI, Erick da Cruz; MENDES-JUNIOR, Celso Teixeira; YOSHIOKA, France Keiko Nascimento; SILVA, Israel Tojal da; TAKAYANAGUI, Osvaldo Massaiti; COVAS, Dimas Tadeu
Fonte: SOC GENERAL MICROBIOLOGY Publicador: SOC GENERAL MICROBIOLOGY
Tipo: Artigo de Revista Científica
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This study evaluated four polymorphisms located in the DC-SIGN (CD209) gene promoter region (positions -336, -332 -201 and -139) in DNA samples from four Brazilian ethnic groups (Caucasians, Afro-Brazilian, Asians and Amerindians) to establish the population distribution of these single-nucleotide polymorphisms (SNPs) and correlated DC-SIGN polymorphisms and infection in samples from human T-cell lymphotropic virus type 1 (HTLV-1)-infected individuals. To identify CD209 SNPs, 452 bp of the CD209 promoter region were sequenced and the genotype and allelic frequencies were evaluated. This is the first study to show genetic polymorphism in the CD209 gene in distinct Brazilian ethnic groups with the distribution of allelic and genotypic frequency. The results showed that -336A and -139A SNPs were quite common in Asians and that the -201T allele was not observed in Caucasians, Asians or Amerindians. No significant differences were observed between individuals with HTLV-1 disease and asymptomatic patients. However, the -336A variant was more frequent in HTLV-1 -infected patients [HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), 80%; healthy asymptomatic HTLV-1 carriers, 90 %] than in the control group (70 %) [P=0.0197...

Membrane transporter proteins are involved in Trichophyton rubrum pathogenesis

MARANHAO, Fernanda C. A.; PAIAO, Fernanda G.; FACHIN, Ana Lucia; MARTINEZ-ROSSI, Nilce M.
Fonte: SOC GENERAL MICROBIOLOGY Publicador: SOC GENERAL MICROBIOLOGY
Tipo: Artigo de Revista Científica
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Trichophyton rubrum is a dermatophyte responsible for the majority of human superficial mycoses. The functional expression of proteins important for the initial step and the maintenance of the infection process were identified previously in T. rubrum by subtraction suppression hybridization after growth in the presence of keratin. In this study, sequences similar to genes encoding the multidrug-resistance ATP-binding cassette (ABC) transporter, copper ATPase, the major facilitator superfamily and a permease were isolated, and used in Northern blots to monitor the expression of the genes, which were upregulated in the presence of keratin. A sequence identical to the TruMDR2 gene, encoding an ABC transporter in T rubrum, was isolated in these experiments, and examination of a T rubrum Delta TruMDR2 mutant showed a reduction in infecting activity, characterized by low growth on human nails compared with the wild-type strain. The high expression levels of transporter genes by T. rubrum in mimetic infection and the reduction in virulence of the Delta TruMDR2 mutant in a disease model in vitro suggest that transporters are involved in T. rubrum pathogenicity.; FAPESP; CNPq; CAPES; FAEPA

Evaluation of Oral Antiseptic Rinsing before Sputum Collection To Reduce Contamination of Mycobacterial Cultures

PERES, Renata L.; PALACI, Moises; LOUREIRO, Rafaela B.; DIETZE, Reynaldo; JOHNSON, John L.; GOLUB, Jonathan E.; RUFFINO-NETTO, A.; MACIEL, Ethel L.
Fonte: AMER SOC MICROBIOLOGY Publicador: AMER SOC MICROBIOLOGY
Tipo: Artigo de Revista Científica
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To assess whether rinsing with oral antiseptics before sputum collection would reduce contamination of mycobacterial cultures, 120 patients with suspected tuberculosis were randomly assigned to rinse with chlorhexidine or cetylpyridinium mouthwash before collection. The culture contamination rate was significantly lower after rinsing with chlorhexidine before collection, especially for cultures grown in MGIT medium.; Fundo de Apoio a Ciencia e Tecnologia do Municipio de Vitoria (FACITEC); International Clinical Operational and Health Services Research and Training Award; Edital ICHORTA[5U2R TW006883-02]

Maxillary sinuses microbiology from patients with chronic rhinosinusitis

MANTOVANI, Karina; BISANHA, Andreia Alessandra; DEMARCO, Ricardo Cassiano; TAMASHIRO, Edwin; MARTINEZ, Roberto; ANSELMO-LIMA, Wilma Terezinha
Fonte: ASSOC BRASILEIRA OTORRINOLARINGOLOGIA & CIRURGIA CERVICOFACIAL Publicador: ASSOC BRASILEIRA OTORRINOLARINGOLOGIA & CIRURGIA CERVICOFACIAL
Tipo: Artigo de Revista Científica
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There isn`t definitive and consistent data concerning the distribution of bacterial species in patients with Chronic Sinusitis (CS). The variability of the results from studies in CS may be due to the different techniques used as collection method, variations in culture methods, previous antibiotic use, and difficulty in distinguishing bacterial flora from pathogenic agents. Study design: Clinical prospective. Aim: To identify the incidence of microorganisms in patients with CRS by growing bacteria from the secretion of the maxillary sinus. Patients and Methods: Cross-sectional study in 62 patients that had undergone FESS for treatment of chronic sinusitis; cultures from the maxillary sinus were obtained. Results: 62 samples, 33 (53.2%) had no growth; 29 (45.2%) counts of aerobic bacteria; one case (1.6%) of fungus growth; we did not find anaerobic bacteria. Pseudomonas aeruginosa was the one more frequently found - 8 samples (27.6%), Staphylococcus aureus and Staphylococcus epidermidis in 4 samples each; Streptococcus pneumoniae in 3 samples (10.4%); other Gram negative agents in 17 samples (31%). Conclusion: In the present study we concluded that Pseudomonas aeruginosa, other Gram negatives bacteria and Staphylococcus spp were the representatives of the bacterial flora found in the paranasal sinuses of patients with CS.

Clinical and Immunological Insights on Severe, Adverse Neurotropic and Viscerotropic Disease following 17D Yellow Fever Vaccination

SILVA, Maria Luiza; ESPIRITO-SANTO, Lucandra Ramos; MARTINS, Marina Angela; SILVEIRA-LEMOS, Denise; PERUHYPE-MAGALHAES, Vanessa; CAMINHA, Ricardo Carvalho; MARANHAO-FILHO, Pericles de Andrade; AUXILIADORA-MARTINS, Maria; MARTINS, Reinaldo de Menezes; GALL
Fonte: AMER SOC MICROBIOLOGY Publicador: AMER SOC MICROBIOLOGY
Tipo: Artigo de Revista Científica
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Yellow fever (YF) vaccines (17D-204 and 17DD) are well tolerated and cause very low rates of severe adverse events (YEL-SAE), such as serious allergic reactions, neurotropic adverse diseases (YEL-AND), and viscerotropic diseases (YEL-AVD). Viral and host factors have been postulated to explain the basis of YEL-SAE. However, the mechanisms underlying the occurrence of YEL-SAE remain unknown. The present report provides a detailed immunological analysis of a 23-year-old female patient. The patient developed a suspected case of severe YEL-AVD with encephalitis, as well as with pancreatitis and myositis, following receipt of a 17D-204 YF vaccination. The patient exhibited a decreased level of expression of Fc-gamma R in monocytes (CD16, CD32, and CD64), along with increased levels of NK T cells (an increased CD3(+) CD16(+/-) CD56(+/-)/CD3(+) ratio), activated T cells (CD4(+) and CD8(+) cells), and B lymphocytes. Enhanced levels of plasmatic cytokines (interleukin-6 [IL-6], IL-17, IL-4, IL-5, and IL-10) as well as an exacerbated ex vivo intracytoplasmic cytokine pattern, mainly observed within NK cells (gamma interferon positive [IFN-gamma(+)], tumor necrosis factor alpha positive [TNF-alpha(+)], and IL-4 positive [IL-4(+)]), CD8(+) T cells (IL-4(+) and IL-5(+))...

Evaluation of Leptospiral Recombinant Antigens MPL17 and MPL21 for Serological Diagnosis of Leptospirosis by Enzyme-Linked Immunosorbent Assays

OLIVEIRA, Tatiane R.; LONGHI, Mariana T.; MORAIS, Zenaide M. de; ROMERO, Eliete C.; BLANCO, Roberta M.; KIRCHGATTER, Karin; VASCONCELLOS, Silvio A.; NASCIMENTO, Ana L. T. O.
Fonte: AMER SOC MICROBIOLOGY Publicador: AMER SOC MICROBIOLOGY
Tipo: Artigo de Revista Científica
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Leptospirosis is a zoonosis of multisystem involvement caused by pathogenic strains of the genus Leptospira. In the last few years, intensive studies aimed at the development of a vaccine have provided important knowledge about the nature of the immunological mechanisms of the host. The purpose of this study was to analyze the immune responses to two recombinant proteins, MPL17 and MPL21 (encoded by the genes LIC10765 and LIC13131, respectively) of Leptospira interrogans serovar Copenhageni in individuals during infection. The recombinant proteins were expressed in Escherichia coli as six-His tag fusion proteins and were purified from the soluble bacterial fraction by affinity chromatography with Ni2+ -charged resin. The recombinant proteins were used to evaluate their ability to bind to immunoglobulin G (IgG) (and IgG subclass) or IgM antibodies in serum samples from patients in the early and convalescent phases of leptospirosis (n = 52) by enzyme-linked immunosorbent assays. The prevalences of total IgG antibodies against MPL17 and MPL21 were 38.5% and 21.2%, respectively. The titers achieved with MPL17 were statistically significantly higher than those obtained by the reference microscopic agglutination test. The specificity of the assay was estimated to be 95.5% for MPL17 and 80.6% for MPL21 when serum samples from individuals with unrelated febrile diseases and control healthy donors were tested. The proteins are conserved among Leptospira strains that cause human and animal diseases. MPL17 and MPL21 are most likely new surface proteins of leptospires...

Evolutionary history of dog rabies in Brazil

KOBAYASHI, Yuki; SUZUKI, Yoshiyuki; ITOU, Takuya; ITO, Fumio H.; SAKAI, Takeo; GOJOBORI, Takashi
Fonte: SOC GENERAL MICROBIOLOGY Publicador: SOC GENERAL MICROBIOLOGY
Tipo: Artigo de Revista Científica
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Although dogs are considered to be the principal transmitter of rabies in Brazil, dog rabies had never been recorded in South America before European colonization. In order to investigate the evolutionary history of dog rabies virus (RABV) in Brazil, we performed a phylogenetic analysis of carnivore RABV isolates from around the world and estimated the divergence times for dog RABV in Brazil. Our estimate for the time of introduction of dog RABV into Brazil was the late-19th to early-20th century, which was later than the colonization period but corresponded to a period of increased immigration from Europe to Brazil. In addition, dog RABVs appeared to have spread to indigenous animals in Brazil during the latter half of the 20th century, when the development and urbanization of Brazil occurred. These results suggest that the movement of rabid dogs, along with human activities since the 19th century, promoted the introduction and expansion of dog RABV in Brazil.; Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan; Japan Society for the Promotion of Science (JSPS)[18405039]; Japan Society for the Promotion of Science (JSPS)[21.4991]; Ministry of Health, Labour and Welfare, Japan[H18-007]

A newly identified protein of Leptospira interrogans mediates binding to laminin

LONGHI, Mariana T.; OLIVEIRA, Tatiane R.; ROMERO, Eliete C.; GONCALES, Amane P.; MORAIS, Zenaide M. de; VASCONCELLOS, Silvio A.; NASCIMENTO, Ana L. T. O.
Fonte: SOC GENERAL MICROBIOLOGY Publicador: SOC GENERAL MICROBIOLOGY
Tipo: Artigo de Revista Científica
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Pathogenic Leptospira is the aetiological agent of leptospirosis, a life-threatening disease that affects populations worldwide. The search for novel antigens that could be relevant in host-pathogen interactions is being pursued. These antigens have the potential to elicit several activities, including adhesion. This study focused on a hypothetical predicted lipoprotein of Leptospira, encoded by the gene LIC12895, thought to mediate attachment to extracellular matrix (ECM) components. The gene was cloned and expressed in Escherichia coli BL21 Star (DE3)pLys by using the expression vector pAE. The recombinant protein tagged with N-terminal hexahistidine was purified by metal-charged chromatography and characterized by circular dichroism spectroscopy. The capacity of the protein to mediate attachment to ECM components was evaluated by binding assays. The leptospiral protein encoded by LIC12895, named Lsa27 (leptospiral surface adhesin, 27 kDa), bound strongly to laminin in a dose-dependent and saturable fashion. Moreover, Lsa27 was recognized by antibodies from serum samples of confirmed leptospirosis specimens in both the initial and the convalescent phases of the disease. Lsa27 is most likely a surface protein of Leptospira as revealed in liquid-phase immunofluorescence assays with living organisms. Taken together...

Escherichia coli strains of serotype O51 : H40 comprise typical and atypical enteropathogenic E. coli strains and are potentially diarrheagenic

MOREIRA, Fabiana C.; VIEIRA, Monica A. M.; FERREIRA, Antonio J. P.; GIRAO, Dennys M.; VAZ, Tania M. I.; ROSA, Ana Claudia P.; KNOBL, Terezinha; IRINO, Kinue; FREYMUELLER, Edna; GOMES, Tania A. T.
Fonte: AMER SOC MICROBIOLOGY Publicador: AMER SOC MICROBIOLOGY
Tipo: Artigo de Revista Científica
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Escherichia coli strains of serotype O51:H40 were studied with regard to the presence of several virulence properties and their genetic diversity and enteropathogenicity in rabbit ileal loops. This serotype encompasses potential enteropathogenic strains mostly classified as being atypical enteropathogenic E. coli (EPEC) strains, which are genetically closer to enterohemorrhagic E. coli than to typical EPEC strains.

Isolation of Candida dubliniensis from denture wearers

GASPAROTO, Thais Helena; DIONISIO, Thiago Jose; OLIVEIRA, Carine Ervolino de; PORTO, Vinicius Carvalho; GELANI, Valeria; SANTOS, Carlos Ferreira; CAMPANELLI, Ana Paula; LARA, Vanessa Soares
Fonte: SOC GENERAL MICROBIOLOGY Publicador: SOC GENERAL MICROBIOLOGY
Tipo: Artigo de Revista Científica
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Candida albicans is considered the most important Candida species able to cause oral infections in denture wearers. In recent years, Candida dubliniensis has emerged as a pathogenic yeast in humans. The close phenotypic similarities of C. albicans and C. dubliniensis have led to the misidentification of these species. In this work, our aim was to verify through PCR the presence of C. dubliniensis in palate and maxillary denture samples from 112 denture wearers presenting with or without denture-related stomatitis (DRS). C. dubliniensis was isolated at low rates from both palate (5.3% and 10.7%) and maxillary denture (5.3% and 8.9%) samples from wearers regardless of the presence of the disease. However, when C. dubliniensis was detected in individuals with DRS, it was always associated with C. albicans. In addition, our results showed that C. albicans was the most commonly identified candidal species in maxillary denture and hard palate samples from DRS patients (78.5% and 89.2%, respectively) as well as from controls (31.2% and 28.5%, respectively). In conclusion, C. dubliniensis was detected in the oral environment of denture wearers. The association of C. dubliniensis with C. albicans occurred in approximately 10% of the DRS cases.; FAPESP[05/60668-9]; FAPESP[06/59612-1]

Penicillin/ampicillin efficacy among children with severe pneumonia due to penicillin-resistant pneumococcus (MIC=4 mu g ml(-1))

NASCIMENTO-CARVALHO, Cristiana M.; CARDOSO, Maria-Regina; BRANDILEONE, Maria-Cristina; FERRERO, Fernando; CAMARGOS, Paulo; BEREZIN, Eitan; RUVINSKY, Raul; SANT`ANNA, Clemax; MARCH, Maria-Fatima; FERIS-IGLESIAS, Jesus; MAGGI, Rubem; BENGUIGUI, Yehuda; CARI
Fonte: SOC GENERAL MICROBIOLOGY Publicador: SOC GENERAL MICROBIOLOGY
Tipo: Artigo de Revista Científica
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Interaction of Mycoplasma genitalium with host cells: evidence for nuclear localization

UENO, Priscilla M.; TIMENETSKY, Jorge; CENTONZE, Victoria E.; WEWER, Jimmy J.; CAGLE, Marianna; STEIN, Murry A.; KRISHNAN, Manickam; BASEMAN, Joel B.
Fonte: SOC GENERAL MICROBIOLOGY Publicador: SOC GENERAL MICROBIOLOGY
Tipo: Artigo de Revista Científica
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Mycoplasma genitalium (Mg) is a mollicute that causes a range of human urogenital infections. A hallmark of these bacteria is their ability to establish chronic infections that can persist despite completion of appropriate antibiotic therapies and intact and functional immune systems. Intimate adherence and surface colonization of mycoplasmas to host cells are important pathogenic features. However, their facultative intracellular nature is poorly understood, partly due to difficulties in developing and standardizing cellular interaction model systems. Here, we characterize growth and invasion properties of two Mg strains (G37 and 1019V). Mg G37 is a high-passage laboratory strain, while Mg 1019V is a low-passage isolate recovered from the cervix. The two strains diverge partially in gene sequences for adherence-related proteins and exhibit subtle variations in their axenic growth. However, with both strains and consistent with our previous studies, a subset of adherent Mg organisms invade host cells and exhibit perinuclear targeting. Remarkably, intranuclear localization of Mg proteins is observed, which occurred as early as 30 min after infection. Mg strains deficient in adherence were markedly reduced in their ability to invade and associate with perinuclear and nuclear sites.; National Institute of Allergy and Infectious Diseases (NIAID/NIH)[U19 AI045429]; U.S. National Institutes of Health (NIH); National Institute of Allergy and Infectious Diseases (NIAID/NIH)[AI41017]; U.S. National Institutes of Health (NIH); UTHSCSA; UTHSCSA; NIH-NCI[P30 CA54174]; U.S. National Institutes of Health (NIH); NIH-NIA[P30 AG013319]; U.S. National Institutes of Health (NIH); U.S. National Institutes of Health (NIH); NIH-NIA[P01AG19316]

Strain variation in ppGpp concentration and RpoS levels in laboratory strains of Escherichia coli K-12

SPIRA, Beny; HU, Xuye; FERENCI, Thomas
Fonte: SOC GENERAL MICROBIOLOGY Publicador: SOC GENERAL MICROBIOLOGY
Tipo: Artigo de Revista Científica
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Laboratory strains and natural isolates of Escherichia coli differ in their level of stress resistance due to strain variation in the level of the sigma factor sigma(S) (or RpoS), the transcriptional master controller of the general stress response. We found that the high level of RpoS in one laboratory strain (MC4100) was partially dependent on an elevated basal level of ppGpp, an alarmone responding to stress and starvation. The elevated ppGpp was caused by two mutations in spoT, a gene associated with ppGpp synthesis and degradation. The nature of the spoT allele influenced the level of ppGpp in both MC4100 and another commonly used K-12 strain, MG1655. Introduction of the spoT mutation into MG1655 also resulted in an increased level of RpoS, but the amount of RpoS was lower in MG1655 than in MC4100 with either the wild-type or mutant spoT allele. In both MC4100 and MG1655, high ppGpp concentration increased RpoS levels, which in turn reduced growth with poor carbon sources like acetate. The growth inhibition resulting from elevated ppGpp was relieved by rpoS mutations. The extent of the growth inhibition by ppGpp, as well as the magnitude of the relief by rpoS mutations, differed between MG1655 and MC4100. These results together suggest that spoT mutations represent one of several polymorphisms influencing the strain variation of RpoS levels. Stress resistance was higher in strains with the spoT mutation...

The pst operon of enteropathogenic Escherichia coli enhances bacterial adherence to epithelial cells

FERREIRA, Gerson Moura; SPIRA, Beny
Fonte: SOC GENERAL MICROBIOLOGY Publicador: SOC GENERAL MICROBIOLOGY
Tipo: Artigo de Revista Científica
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Enteropathogenic Escherichia coli (EPEC) adheres in vivo and in vitro to epithelial cells. Two main adhesins, the bundle-forming pilus and intimin, encoded by the Up operon and eae, respectively, are responsible for the localized and the intimate adherence phenotypes. Deletion of the pst operon of EPEC abolishes the transport of inorganic phosphate through the phosphate-specific transport system and causes the constitutive expression of the PHO regulon genes. In the absence of pst there is a decrease in the expression of the main EPEC adhesins and a reduction in bacterial adherence to epithelial cells in vitro. This effect is not related to PHO constitutivity, because a Delta pst phoB double mutant that is defective in the transcription of the PHO genes also displayed low levels of adherence and expression of adhesins. Likewise, a PHO-constitutive phoR mutation did not affect bacterial adherence. The expression of the per operon, which encodes the Up and ler regulators PerA and PerC, is also negatively affected by the pst deletion. Overall, the data presented here demonstrate that the pst operon of EPEC plays a positive role in the bacterial adherence mechanism by increasing the expression of perA and perC and consequently the transcription of bfp and eae.

Analysis of the genome of Spodoptera frugiperda nucleopolyhedrovirus (SfMNPV-19) and of the high genomic heterogeneity in group II nucleopolyhedroviruses

WOLFF, Jose Luiz Caldas; VALICENTE, Fernando Hercos; MARTINS, Renata; OLIVEIRA, Juliana Velasco De Castro; ZANOTTO, Paolo Marinho De Andrade
Fonte: SOC GENERAL MICROBIOLOGY Publicador: SOC GENERAL MICROBIOLOGY
Tipo: Artigo de Revista Científica
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The genome of the most virulent among 22 Brazilian geographical isolates of Spodoptera frugiperda nucleopolyhedrovirus, isolate 19 (SfMNPV-1 9), was completely sequenced and shown to comprise 132 565 bp and 141 open reading frames (ORFs). A total of 11 ORFs with no homology to genes in the GenBank database were found. Of those, four had typical baculovirus; promoter motifs and polyadenylation sites. Computer-simulated restriction enzyme cleavage patterns of SfMNPV-1 9 were compared with published physical maps of other SfMNPV isolates. Differences were observed in terms of the restriction profiles and genome size. Comparison of SfMNPV-1 9 with the sequence of the SfMNPV isolate 3AP2 indicated that they differed due to a 1427 bp deletion, as well as by a series of smaller deletions and point mutations. The majority of genes of SfMNPV-1 9 were conserved in the closely related Spodoptera exigua NPV (SeMNPV) and Agrotis segetum NPV (AgseMNPV-A), but a few regions experienced major changes and rearrangements. Synthenic maps for the genomes of group 11 NPVs revealed that gene collinearity was observed only within certain clusters. Analysis of the dynamics of gene gain and loss along the phylogenetic tree of the NPVs showed that group 11 had only five defining genes and supported the hypothesis that these viruses form ten highly divergent ancient lineages. Crucially...

Genetic diversity of heat-labile toxin expressed by enterotoxigenic Escherichia coli strains isolated from humans

LASARO, M. A.; RODRIGUES, J. F.; MATHIAS-SANTOS, C.; GUTH, B. E. C.; BALAN, A.; SBROGIO-ALMEIDA, M. E.; FERREIRA, L. C. S.
Fonte: AMER SOC MICROBIOLOGY Publicador: AMER SOC MICROBIOLOGY
Tipo: Artigo de Revista Científica
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The natural diversity of the eft operons, encoding the heat-labile toxin LT-I (LT), carried by enterotoxigenic Escherichia coli (ETEC) strains isolated from humans was investigated. For many years, LT was supposed to be represented by a rather conserved toxin, and one derivative, produced by the reference H10407 strain, was intensively studied either as a virulence factor or as a vaccine adjuvant. Amplicons encompassing the two LT-encoding genes (eltA and eltB) of 51 human-derived ETEC strains, either LT+ (25 strains) only or LT+/ST+ (26 strains), isolated from asymptomatic (24 strains) or diarrheic (27 strains) subjects, were subjected to restriction fragment length polymorphism (RFLP) analysis and DNA sequencing. Seven polymorphic RFLP types of the H10407 strain were detected with six (BsaI, DdeI, HhaI, HincII, HphI, and MspI) restriction enzymes. Additionally, the single-nucleotide polymorphic analysis revealed 50 base changes in the eft operon, including 21 polymorphic sites at eltA and 9 at eltB. Based on the deduced amino acid sequences, 16 LT types were identified, including LT1, expressed by the H10407 strain and 23 other strains belonging to seven different serotypes, and LT2, expressed by 11 strains of six different serotypes. In vitro experiments carried out with purified toxins indicated that no significant differences in GM1-binding affinity could be detected among LT1...