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1.
Ther Clin Risk Manag ; 16: 749-758, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32884276

RESUMO

The outlook for transthyretin amyloidosis (ATTR) is changing with the availability of new and emerging treatments. ATTR now appears to be more common than previously thought and is no longer viewed as an obscure diagnosis with a grim prognosis. Now more than ever, there is growing emphasis on the need for early diagnosis because the treatments appear to be most effective if started in earlier stages of the disease. Diagnosing ATTR is a challenge as it may initially present with nonspecific symptoms and it is often thought of as a diagnosis of exclusion. Increased awareness is imperative as new treatments offer hope and have the potential to change the disease trajectory. ATTR commonly presents with neurological and cardiac features. Transthyretin (TTR) is a protein produced in the liver which misfolds either due to genetic mutations or due to aging and results in deposition of amyloid fibrils in organs and tissues. Apart from the traditional imaging modalities, newer techniques including echocardiographic strain imaging, magnetic resonance imaging (MRI), and nuclear scintigraphy, as well as the increased availability of genetic testing are aiding in making a timely diagnosis. In this review, we present the current understanding of the ATTR disease process, diagnostic and surveillance approaches, newer treatment modalities, and the future directions.

2.
Equine Vet J ; 51(5): 696-700, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30600546

RESUMO

BACKGROUND: A comprehensive study of the effect of supramaximal exercise in lipid homeostasis of Thoroughbreds provides the basis for future research on the role of lipids on energy metabolism in racehorses. OBJECTIVE: To compare the plasma lipidome of Thoroughbreds before and after supramaximal exercise using an untargeted lipidomics approach. STUDY DESIGN: Pilot experimental study. METHODS: Four Thoroughbred horses were used. The maximal oxygen consumption (VO2 max ) was calculated for each horse. Horses then underwent treadmill exercise at the speed for which the oxygen requirements had been calculated to be 115% VO2 max . Plasma samples were obtained before (T0) and immediately (T1), 15 (T2) and 30 (T3) minutes post-exercise, and evaluated using liquid chromatography/mass spectrometry. Data analysis consisted of principal component analysis and one-way repeated measures analysis of variance. RESULTS: A total of 933 plasma lipids were detected. Supramaximal exercise-induced significant changes in the signal intensity of 13 lipids; all ubiquitous in the organism as major components of biological membranes or energy substrates. MAIN LIMITATIONS: A treadmill was used to replicate track conditions. Also, sample size involved only four horses and the statistical analyses failed to achieve the desired power of 80%. CONCLUSIONS: The findings in this pilot study suggest that supramaximal exercise induces changes in specific plasma lipids in Thoroughbred racehorses. While the biological significance of these findings remains to be determined, these results provide baseline information for future studies in lipidomics applied to equine exercise physiology. Further research is warranted to better understand the role of lipids on energy metabolism in Thoroughbred racehorses.


Assuntos
Cavalos/metabolismo , Metabolismo dos Lipídeos/fisiologia , Condicionamento Físico Animal/fisiologia , Animais , Cavalos/sangue , Consumo de Oxigênio , Projetos Piloto
3.
Cell Death Discov ; 1: 15004, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-27551440

RESUMO

The novel regulation mechanism in mtDNA-less cells was investigated. Very low mtDNA copy in mtDNA-less 206 ρ° cells was identified. But no 13 mitochondria-specific proteins were translated in 206 ρ° cells. Their mitochondrial respiration complexes V, III and II were 86.5, 29.4 and 49.6% of 143B cells, respectively. Complexes I and IV completely lack in 206 ρ° cells. Non-mitochondrial respiration to generate ATP in 206 ρ° cells was discovered. The expression levels of some mitochondrial RNAs including 12S rRNA, COX1, COX2, COX3, ND4 and ND5 were low. However, ND1, ND3 and Cyto b were not expressed in 206 ρ° cells. Unequal transcription of mitochondrial RNAs indicated the post-transcriptional cleavage and processing mechanisms in the regulation of mitochondrial gene expression in 206 ρ° cells. MicroRNAs (miRNAs) may modulate these mitochondrial RNA expression in these cells. RNA-induced silencing complex indeed within 206 ρ° cell mitochondria indicated miRNAs in 206 ρ° cell mitochondria. miRNA profile in mtDNA-less 206 ρ° cells was studied by next-generation sequencing of small RNAs. Several mitochondria-enriched miRNAs such as miR-181c-5p and miR-146a-5p were identified in 206 ρ° cell mitochondria. miR-181c-5p and miR-146a-5p had 23 and 19 potential targets on mitochondrial RNAs respectively, and these two miRNAs had multiple targets on mitochondria-associated messenger RNAs encoded by nuclear genes. These data provided the first direct evidence that miRNAs were imported into mitochondria and regulated mitochondrial RNA expressions.

4.
Vet Rec ; 160(10): 343-5, 2007 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-17351179

RESUMO

Avian influenza presents both challenges and opportunities to leaders around the world engaged in pandemic influenza preparedness planning. Most resource-poor countries will be unable to stockpile antivirals or have access to eventual human vaccines for pandemic flu. Preparedness plans, directed at controlling avian influenza at the source, enable countries simultaneously to promote national and global health, animal welfare and international development. Improving the veterinary infrastructure and capacity of resource-poor countries is one way to prevent potential pandemic flu deaths in resource-rich countries. In this article, Amanda Martinot, James Thomas, Alejandro Thiermann and Nabarun Dasgupta argue that national health leaders need to consider more comprehensive strategies that incorporate veterinary surveillance and improvements in veterinary infrastructure for the control of avian influenza epizootics as part of national pandemic preparedness planning. This, they argue, will require a shift in attitude, from thinking in terms of preparation for an inevitable pandemic to pre-emption of the potential pandemic through prevention measures in the animal population.


Assuntos
Surtos de Doenças/veterinária , Influenza Aviária/epidemiologia , Influenza Aviária/prevenção & controle , Animais , Planejamento em Desastres , Surtos de Doenças/prevenção & controle , Humanos , Aves Domésticas , Medicina Veterinária
5.
Anim Genet ; 38(2): 141-6, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17326800

RESUMO

The Rhadinovirus ovine herpesvirus-2 (OvHV-2) is the most common causative agent of malignant catarrhal fever (MCF) in clinically susceptible ruminants including cattle and bison. American bison (Bison bison) are highly susceptible to clinical MCF. Nevertheless, approximately 20% of bison on ranches or in feedlots become infected with the virus without developing clinical disease. Defining the genetic basis for differences in susceptibility between bison could facilitate development of improved control strategies for MCF. One genetic region that influences susceptibility to infectious diseases is the major histocompatibility complex (MHC). In this study, a Bison bison (Bibi) DRB3 oligonucleotide microarray was used to type 189 bison from 10 herds where MCF outbreaks had occurred. Binary logistic regression was used to classify DRB3 alleles as resistant (R), susceptible (S) or neutral (N). Animals were reclassified using six DRB3 genotype categories: N/N, N/R, N/S, R/S, R/R and S/S. Analysis of homogeneity across herds showed that there was a herd effect. Consequently, a penalized logistic regression model was run with herd and genotype categories as the explanatory variables. The R/R genotype was associated with resistance to MCF (P = 0.0327), while the S/S genotype was associated with clinical MCF (P = 0.0069). This is the first evidence that MHC class IIa polymorphism is associated with resistance or susceptibility to OvHV-2-induced MCF.


Assuntos
Bison , Genes MHC da Classe II/genética , Infecções por Herpesviridae/veterinária , Imunidade Inata/genética , Febre Catarral Maligna/genética , Febre Catarral Maligna/imunologia , Infecções Tumorais por Vírus/veterinária , Animais , Primers do DNA , Frequência do Gene , Genótipo , Infecções por Herpesviridae/genética , Infecções por Herpesviridae/imunologia , Modelos Logísticos , Análise de Sequência com Séries de Oligonucleotídeos , Infecções Tumorais por Vírus/genética , Infecções Tumorais por Vírus/imunologia
6.
Arch Environ Contam Toxicol ; 51(4): 529-36, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16998632

RESUMO

Laboratory bioassays consisting of sediments spiked with three concentrations (30, 130, and 260 microg g-1 As dry wt) of arsenic (As+3) were used to assess morphologic responses and growth in Chironomus tentans larvae. Chironomid larvae were raised in contaminated sediments from egg stage to emergence, and mouthpart abnormalities, larval length, and larval head width were used as end points to determine differences between metal-spiked and control specimens. C. tentans exhibited significantly higher mouthpart deformity proportions, smaller body sizes, smaller head widths, and slower development than control larvae. Our results demonstrate a dose-response relationship between As and mentum deformities in C. tentans. However, the proportion of deformed larvae did not increase with time in the treatment tanks. Results demonstrate that As induces mouthpart abnormalities at various concentrations. This research provides more support for the use of chironomid abnormalities as a tool for the assessment of heavy-metal pollution in aquatic systems.


Assuntos
Anormalidades Induzidas por Medicamentos , Arsênio/toxicidade , Chironomidae/efeitos dos fármacos , Crescimento/efeitos dos fármacos , Animais , Chironomidae/crescimento & desenvolvimento , Relação Dose-Resposta a Droga , Larva/efeitos dos fármacos
7.
Lupus ; 14(11): 910-3, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16335585

RESUMO

Lymphomas, both within and outside the central nervous system, are uncommon among patients with systemic lupus erythematosus (SLE). We describe a 58-year old Korean woman with SLE who presented with acute headache and confusion in the setting of prednisone and mycophenolate mofetil (MMF) therapy used to treat focal proliferative and membranous lupus nephritis. Three-dimensional brain magnetic resonance imaging (MRI) showed two peripherally ('ring') enhancing lesions within the basal ganglia, bilaterally, with associated mass effect and subfalcine herniation. A brain biopsy revealed an Epstein-Barr virus (EBV)-positive diffuse large B cell lymphoma. This is the first description of CNS lymphoma in a patient treated with MMF for lupus nephritis. While intracerebral lymphoma in the immunocompromised patient with lupus is rare, this disorder should be considered in the differential diagnosis of new-onset neurological symptoms among such patients.


Assuntos
Neoplasias Encefálicas/etiologia , Imunossupressores/administração & dosagem , Nefrite Lúpica/tratamento farmacológico , Linfoma de Células B/etiologia , Ácido Micofenólico/análogos & derivados , Neoplasias Encefálicas/patologia , Feminino , Humanos , Nefrite Lúpica/complicações , Linfoma de Células B/patologia , Pessoa de Meia-Idade , Ácido Micofenólico/administração & dosagem
8.
Plant Dis ; 89(2): 146-152, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30795216

RESUMO

The effects of tuber depth, soil type, and soil moisture on potato tuber infection due to Phytophthora infestans were assessed under greenhouse conditions in soil contained in large pots. Healthy tubers were used to assess infection and were either hand buried in soil at specific depths or naturally formed from potato plants growing in the soil. A spore suspension of P. infestans was chilled to induce zoospore formation and a suspension of resulting zoospores and sporangia were applied to the soil. Soil depth at which tubers became infected was used to determine the extent of spore movement in the soils. Tuber infection significantly decreased with increasing soil depth. Most infected tubers were found at the surface of soil; infection was rare on tubers at 5 cm or deeper in the soil. Amount of tuber infection varied among soil types. Significantly less tuber infection occurred in a Shano silt loam than in medium and fine sands. Only tubers on the soil surface were infected in the Shano silt loam. Depth in soil at which tubers became infected did not differ significantly among Quincy fine sand, Quincy loamy fine sand, and Quincy medium sand. Increased soil moisture did not significantly increase the soil depth at which tuber infection occurred, regardless of the soil type.

9.
Arch Environ Contam Toxicol ; 42(3): 286-91, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11910456

RESUMO

Elevated morphological deformity rates in Chironomidae larvae have been attributed to such pollutants as oil tars, pesticides, organochlorines, and heavy metals. The potential of chironomids as biological indicators of heavy metal contamination and bioavailability in a contaminated ecosystem was assessed. Chironomid larvae and river sediment were collected from the Coeur d' Alene River system, Idaho, USA, contaminated with heavy metals from mining activities. Chironomid larvae collected at contaminated sites exhibited mouthpart deformity proportions between 3.8 and 10.3% compared to the control site of 0.9%. As, Cd, Cu, Ni, Pb, and Zn were determined in both larvae and sediment samples. Significant correlation between metal concentrations and deformity rates were observed for all metals except Ni. The data also suggests that feeding habits may influence differences in pollution tolerance among genera.


Assuntos
Chironomidae/crescimento & desenvolvimento , Anormalidades Congênitas/etiologia , Monitoramento Ambiental , Metais Pesados/efeitos adversos , Poluentes da Água/efeitos adversos , Animais , Disponibilidade Biológica , Biomarcadores , Anormalidades Congênitas/veterinária , Dieta , Ecossistema , Exposição Ambiental , Larva/crescimento & desenvolvimento
10.
Proc Natl Acad Sci U S A ; 98(26): 15342-7, 2001 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-11742070

RESUMO

The neuronal nucleus plays a vital role in information processing, but whether it supports computational functions such as paired-pulse facilitation, comparable to synapses, is unclear. Ca(2+)-dependent movement of calmodulin (CaM) to the nucleus is highly responsive to Ca(2+) entry through L-type channels and promotes activation of the transcription factor CREB (cAMP-responsive element binding protein) through phosphorylation by CaM-sensitive kinases. We characterized key features of this CaM translocation and its possible role in facilitation of nuclear signaling. Nuclear CaM was elevated within 15 s of stimulus onset, preceding the first signs of CREB phosphorylation in hippocampal pyramidal neurons. Depolarization-induced elevation of nuclear CaM also was observed in cerebellar granule cells, neocortical neurons, and dentate gyrus granule cells. Nuclear translocation of CaM was not blocked by disruption of actin filaments or microtubules, or by emptying endoplasmic reticulum Ca(2+) stores with thapsigargin. Translocation of fluorescently tagged CaM was prevented by fusing it with the Ca(2+)/CaM binding peptide M13, suggesting that nuclear CaM accumulation depends on association with endogenous Ca(2+)/CaM binding proteins. To determine whether increased nuclear [CaM] might influence subsequent nuclear signal processing, we compared responses to two consecutive depolarizing stimuli. After a weak "priming" stimulus that caused CaM translocation, CREB phosphorylation caused by a subsequent stimulus was significantly faster, more sensitive to Ca(2+) elevation, and less specifically dependent on Ca(2+) influx through L-type channels. CaM translocation not only supports rapid signaling to the nucleus, but also could provide a "memory" for facilitatory effects of repeated neural activity, seen in altered phosphorylated CREB dynamics and Ca(2+) channel dependence.


Assuntos
Calmodulina/metabolismo , Núcleo Celular/metabolismo , Hipocampo/metabolismo , Neurônios/metabolismo , Animais , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Hipocampo/citologia , Transporte Proteico , Ratos
11.
J Pers Soc Psychol ; 81(5): 800-14, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11708558

RESUMO

Two experiments examined whether exposure to pictures of admired and disliked exemplars can reduce automatic preference for White over Black Americans and younger over older people. In Experiment 1, participants were exposed to either admired Black and disliked White individuals, disliked Black and admired White individuals, or nonracial exemplars. Immediately after exemplar exposure and 24 hr later, they completed an Implicit Association Test that assessed automatic racial attitudes and 2 explicit attitude measures. Results revealed that exposure to admired Black and disliked White exemplars significantly weakened automatic pro-White attitudes for 24 hr beyond the treatment but did not affect explicit racial attitudes. Experiment 2 provided a replication using automatic age-related attitudes. Together, these studies provide a strategy that attempts to change the social context and, through it, to reduce automatic prejudice and preference.


Assuntos
Atitude , Automatismo , Preconceito , Adulto , Negro ou Afro-Americano , Envelhecimento , Associação , Feminino , Humanos , Masculino , Semântica , Percepção Social , Estereotipagem , População Branca
12.
Environ Toxicol Chem ; 20(11): 2475-81, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11699772

RESUMO

Laboratory experiments were used to assess morphological responses of Chironomus tentans larvae exposed to three levels of zinc and lead. Chironomus tentans egg masses were placed into triplicate control and metal-spiked aquaria containing the measured concentrations 1,442, 3,383, and 5,562 microg/g Pb dry weight and 1,723, 3,743, and 5,252 microg/g Zn dry weight. Larvae were collected at 10-d intervals after egg masses were placed in aquaria until final emergence. Larvae were screened for mouthpart deformities and metal body burdens. Deformities increased with time of exposure in both Zn and Pb tanks. Deformity rates between the three Zn concentrations differed statistically, with low and medium Zn levels containing the highest overall deformity rates of 12%. Deformity rates for larvae held in the Pb aquaria were found to differ significantly. Larvae in the low-Pb tanks had a deformity rate of 9%. Larvae and water from both the Zn and Pb aquaria had increasing metal concentrations with increasing sediment metal concentration. Results demonstrate that Zn and Pb each induce chironomid mouthpart deformities at various concentrations. However, a clear dose-related response was not demonstrated. Our research provides more support for the potential use of chironomid deformities as a tool for the assessment of heavy metal pollution in aquatic systems.


Assuntos
Chironomidae/crescimento & desenvolvimento , Anormalidades Congênitas/veterinária , Chumbo/efeitos adversos , Poluentes da Água/efeitos adversos , Zinco/efeitos adversos , Animais , Chironomidae/efeitos dos fármacos , Relação Dose-Resposta a Droga , Monitoramento Ambiental , Sedimentos Geológicos/química , Larva/crescimento & desenvolvimento , Testes de Toxicidade
13.
J Bacteriol ; 183(22): 6636-44, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11673434

RESUMO

Flagellar number in Pseudomonas aeruginosa is controlled by FleN, a putative ATP/GTP binding protein. Disruption of fleN results in multiflagellation of the otherwise monoflagellate strains PAK and PAO1 and is associated with a chemotactic defect. We propose that flagellar number is maintained by the antiactivator FleN, which downregulates flagellar genes by binding to their transcriptional activator, FleQ, an enhancer binding protein belonging to the NifA subfamily. In this report we demonstrate direct interaction of FleN and FleQ in the yeast two-hybrid system. Mutagenesis of the putative ATP/GTP binding motif in FleN(24K-->Q) and truncation of FleN at either the N or C terminus abrogates this interaction. FleN does not inhibit the DNA binding ability of FleQ in vitro, thus indicating that it probably utilizes another mechanism(s) to serve as a FleQ antiactivator.


Assuntos
Proteínas de Bactérias/metabolismo , Flagelos/metabolismo , Pseudomonas aeruginosa/metabolismo , Transativadores/metabolismo , Proteínas de Ligação a DNA , Mutação , Transativadores/química , Transativadores/genética , Técnicas do Sistema de Duplo-Híbrido
14.
J Nutr ; 131(5): 1548-54, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11340114

RESUMO

Conjugated linoleic acids (CLA) are conjugated isomers of linoleic acid, which may promote health with regard to cancer, heart disease, diabetes, bone formation, growth modulation and immunity. The c9,t11 isomer of CLA, rumenic acid (RA), is the major isomer present in the diet. However, dietary intakes of CLA and RA by humans have not been examined rigorously, nor has the relationship between dietary CLA or RA and health (e.g., body composition). Three-day dietary records (DR) were collected from adult men (n = 46) and women (n = 47) and analyzed using a nutrient database modified to contain total CLA and RA. Simultaneously, 3-d food duplicates (FD) were collected to determine analytically individual fatty acid intakes, including those of total CLA and RA. Chronic total CLA and RA intakes were estimated using a semiquantitative food-frequency questionnaire (FFQ). Body composition was estimated using body mass index and percentage of body fat. Total CLA intake was estimated from FD to be 212 +/- 14 and 151 +/- 14 mg/d (mean +/- SEM) for men and women, respectively; RA intake was estimated to be 193 +/- 13 and 140 +/- 14 mg/d for men and women, respectively. In general, CLA and RA intakes estimated by DR and FFQ were significantly lower than those estimated by FD. Body composition was not significantly related to dietary total CLA or RA intake. In conclusion, results suggest that DR and FFQ methodologies are not reliable estimators of individual total CLA and RA intakes and may underestimate total CLA and RA intakes of groups. Intake of total CLA and RA was found to be significantly lower than that suggested previously by others.


Assuntos
Registros de Dieta , Ácido Linoleico/administração & dosagem , Lipídeos/sangue , Adulto , Antropometria , Índice de Massa Corporal , Inquéritos sobre Dietas , Feminino , Humanos , Masculino , Estados Unidos
15.
Tuber Lung Dis ; 80(3): 141-59, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10970762

RESUMO

By subtractive hybridization, we isolated genes, differentially expressed in virulent strain (dev), that are expressed at higher levels in the virulent Mycobacterium tuberculosis H37Rv strain in comparison to its avirulent counterpart, H37Ra, and consequently may be associated with the virulence phenotype of M. tuberculosis. A two-component system, devR-devS, was identified by DNA sequencing of a dev clone. DevR, the predicted gene product of devR, is a response regulator (RR) in the NarL/ UhpA subfamily of two-component systems. The devS gene product displayed homology with histidine protein kinases (HPKs) including UhpB, NarX and NarQ. The devR-devS locus is preceded by gene Rv3134c that encodes a putative alanine-aline- rich protein. This locus was conserved in M. tuberculosis and M. bovis BCG but not in other mycobacteria. A devR -lacZ transcription fusion demonstrated beta-galactosidase activity in M. smegmatis and in M. tuberculosis. The devR and devS genes were cotranscribed and the levels of their transcripts were lower in two isolates of the avirulent H37Ra strain in comparison to the virulent H37Rv strain of M. tuberculosis. The level of DevR protein was also lower in one of the H37Ra strains in comparison to the H37Rv strain. However, in a third isolate of H37Ra, RNA and protein expression was equivalent to that in the H37Rv strain. Electron microscopic immunogold analysis of M. tuberculosis grown in laboratory medium and within human monocytes revealed specific labelling for DevR protein within the bacteria and the phagosomal lumen of infected monocytes. These findings collectively suggest a potential role for devR-devS in the regulation of genetic programmes unique to the tubercle bacillus.


Assuntos
Genes Bacterianos , Mycobacterium tuberculosis/genética , Células Cultivadas , Regulação Bacteriana da Expressão Gênica , Dados de Sequência Molecular , Monócitos/citologia , Monócitos/microbiologia , Mycobacterium tuberculosis/citologia , Mycobacterium tuberculosis/patogenicidade , Hibridização de Ácido Nucleico , Fenótipo , Alinhamento de Sequência , Análise de Sequência de DNA , Transdução de Sinais/genética , Transcrição Gênica , Técnicas do Sistema de Duplo-Híbrido , Virulência/genética
16.
Biometrics ; 56(2): 402-8, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10877296

RESUMO

The chi2 goodness-of-fit test is commonly used for testing if animals use resources in proportion to availability. This method assumes independence of resource selection among animals. In reality, this assumption is violated if animals display antisocial or gregarious behavior. Data from a study of sharp-tailed grouse in eastern Washington suggested some dependency among observations. Realizing that this dependency can have a great influence on inference for resource selection data, we develop a technique to incorporate information on dependent observations through a simple adjustment of the usual goodness-of-fit statistic. We also demonstrate how confidence intervals on proportional use may be modified for dependent observations. Simulation is used to compare our method to other methods.


Assuntos
Animais Selvagens , Comportamento Animal , Distribuição de Qui-Quadrado , Animais , Biometria/métodos , Aves , Conservação dos Recursos Naturais , Modelos Estatísticos , Método de Monte Carlo
17.
Infect Immun ; 68(3): 1474-9, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10678962

RESUMO

Binding of Pseudomonas aeruginosa strain PAK to mucin has been shown to be mediated by the flagellar cap protein, product of the fliD gene. Since the flagellar cap is very likely an exposed structure, the FliD polypeptide should be recognized by the host immune system, analogous to the recognition of dominant epitopes located in the exposed parts of the flagellin polypeptide within the assembled flagellum. In P. aeruginosa, a number of distinct flagellin variants are made, and these variable sequences presumably allow the newly infected P. aeruginosa to escape recognition by the antibody induced during a previous infection. Since similar mechanisms may direct the selection of FliD variants, we examined the extent of sequence heterogeneity among various FliD sequences among a selected group of P. aeruginosa. The results of PCR and nucleotide sequencing of the fliD region of eight different P. aeruginosa strains (laboratory strains PAK, PAO1, and PA103; clinical strains 1244, CS2, and CS32; cystic fibrosis strains CS29 and MDR) suggested that there were two distinct types of FliD in P. aeruginosa, which we named A type and B type. The results of Western blotting using the polyclonal antibodies raised against the purified FliD of A type (PAK) or B type (PAO1) further confirmed the existence of two distinct antigenic types of FliD proteins, with no cross-reactivity between the two serotypes. Further Western immunoblot analysis of the same strains using polyclonal FliC antibody showed that the strains with A-type FliD possessed a-type FliC and those with B-type FliD had b-type FliC. Similar Western blot analyses of 50 more P. aeruginosa strains obtained from varied sources revealed that all strains contained either A-type or B-type FliD, suggesting the existence of only two types of FliD in P. aeruginosa and indicating that fliC and fliD were coinherited. This limited diversity of FliC and FliD serotypes seems to be a unique feature of flagellar proteins. A chromosomal mutant having an insertion in the fliD gene of P. aeruginosa PAO1 was constructed. The motility defect of this mutant and a previously constructed PAK fliD mutant was better complemented with the fliD gene of the homologous types.


Assuntos
Proteínas de Bactérias/análise , Flagelos/química , Pseudomonas aeruginosa/química , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Flagelina/genética , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , Pseudomonas aeruginosa/classificação , Sorotipagem
18.
J Bacteriol ; 182(2): 357-64, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10629180

RESUMO

The single polar flagellum of Pseudomonas aeruginosa plays an important role in the pathogenesis of infection by this organism. However, regulation of the assembly of this organelle has not been delineated. In analyzing the sequence available at the Pseudomonas genome database, an open reading frame (ORF), flanked by flagellar genes flhF and fliA, that coded for a protein (280 amino acids) with an ATP-binding motif at its N terminus was found. The ORF was inactivated by inserting a gentamicin cassette in P. aeruginosa PAK and PAO1. The resulting mutants were nonmotile on motility agar plates, but under a light microscope they exhibited random movement and tumbling behavior. Electron microscopic studies of the wild-type and mutant strains revealed that the mutants were multiflagellate, with three to six polar flagella per bacterium as rather than one as in the wild type, indicating that this ORF was involved in regulating the number of flagella and chemotactic motility in P. aeruginosa. The ORF was named fleN. An intact copy of fleN on a plasmid complemented the mutant by restoring motility and monoflagellate status. The beta-galactosidase activities of eight flagellar operon or gene promoters in the wild-type and fleN mutant strains revealed a direct correlation between six promoters that were upregulated in the fleN mutant (fliLMNOPQ, flgBCDE, fliEFG, fliDS orf126, fleSR, and fliC) and positive regulation by FleQ, an NtrC-like transcriptional regulator for flagellar genes. Based on these results, we propose a model where FleN influences FleQ activity (directly or indirectly) in regulating flagellar number in P. aeruginosa.


Assuntos
Flagelos/genética , Pseudomonas aeruginosa/genética , Transativadores/genética , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Sequência de Bases , Microscopia Eletrônica , Dados de Sequência Molecular , Pseudomonas aeruginosa/ultraestrutura , Alinhamento de Sequência , Software
19.
J Pers Soc Psychol ; 77(5): 991-1003, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10573876

RESUMO

Two experiments tested whether the perceived entitativity of groups (i.e., cohesiveness) influences judgments about those groups, in terms of both their observable physical properties and underlying psychological traits. Entitativity was manipulated with groups whose members were similar or dissimilar in skin color. Experiment 1 demonstrated that beliefs about entitativity elicited more accurate judgments of skin color for entitative than nonentitative social groups, although memory for individual members of entitative groups was relatively impoverished. Experiment 2 revealed that entitative groups were viewed as not only physically similar but also psychologically homogeneous and elicited strong negative trait and behavioral judgments. Together, these findings suggest that physical properties (e.g., similarity) can create perceptions of psychological "groupness" that have important consequences for group perception.


Assuntos
Etnicidade/psicologia , Pigmentação da Pele , Identificação Social , Percepção Social , Adulto , Feminino , Humanos , Individualidade , Julgamento , Masculino , Preconceito , Distribuição Aleatória
20.
J Virol ; 73(4): 2798-802, 1999 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10074127

RESUMO

A 46-kDa receptor, coxsackievirus-adenovirus (Ad) receptor (CAR), mediates cell attachment of a number of different Ad serotypes; however, not all Ad serotypes utilize this receptor for infection. Moreover, the precise amino acid sequences in the Ad fiber protein that mediate cell attachment have yet to be identified. We investigated the interaction of subgroup D Ads with human ocular cells. Ad serotype 37 (Ad37), a virus associated with epidemic keratoconjunctivitis, but not a closely related virus serotype, Ad19p, exhibited preferential binding to and infection of human conjunctival cells. A single amino acid substitution in the Ad19p fiber distal domain (knob), Glu240 to Lys, conferred binding to conjunctival cells, while the reverse substitution in the Ad37 fiber abrogated cell binding. These findings provide new information on the fiber sequences that regulate Ad host cell tropism.


Assuntos
Infecções por Adenoviridae/virologia , Adenoviridae/genética , Proteínas do Capsídeo , Capsídeo/genética , Túnica Conjuntiva/virologia , Sequência de Aminoácidos , Substituição de Aminoácidos , Capsídeo/metabolismo , Linhagem Celular , Humanos , Modelos Moleculares , Dados de Sequência Molecular , Replicação Viral/genética
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