Recycling of the high valence states of heme proteins by cysteine residues of thimet-oligopeptidase

The peptidolytic enzyme THIMET-oligopeptidase (TOP) is able to act as a reducing agent in the peroxidase cycle of myoglobin (Mb) and horseradish peroxidase (HRP). The TOP-promoted recycling of the high valence states of the peroxidases to the respective resting form was accompanied by a significant decrease in the thiol content of the peptidolytic enzyme. EPR (electron paramagnetic resonance) analysis using DBNBS spin trapping revealed that TOP also prevented the formation of tryptophanyl radical in Mb challenged by H2O2. The oxidation of TOP thiol groups by peroxidases did not promote the inactivating oligomerization observed in the oxidation promoted by the enzyme aging. These findings are discussed towards a possible occurrence of these reactions in cells.FAPESP (08/04948-0)CNPqUNIFESPUFABCCAPE

Investigação sorológica de espécies de Ehrlichia em cães, equinos e humanos de um assentamento rural do sul do Brasil

Objetivou-se determinar a soroprevalência de Ehrlichia spp. e os fatores de risco associados a exposição em uma população restrita de cães, cavalos e humanos altamente expostos a picadas de carrapatos em um assentamento rural brasileiro utilizando um teste comercial de ELISA rápido e dois testes de imunofluorescência indireta (IFI) com antígenos brutos de E. canis e E. chaffeensis. Amostras de soro de 132 cães, 16 cavalos e 100 humanos foram utilizadas. Cinquenta e seis/132 (42,4%) cães foram soropositivos para E. canis. Cães > um ano apresentaram mais chance de serem soropositivos para E. canis do que cães ≤ um ano (p =0,0051). Dez/16 (62,5%) e 8/16 (50%) cavalos foram soropositivos pelo ELISA comercial e IFI, respectivamente. Cinco/100 (5%) humanos foramsoropositivos para E. canis e E. chaffeensis. Rhipicephalus sanguineus (n= 291, 97,98%) nos cães e A. cajennense (n = 25, 96,15%) nos cavalos foram os carrapatos mais encontrados. Concluindo, anticorpos anti-Ehrlichia spp. foram encontrados em cavalos; entretanto, a ausência de uma caracterização molecular impede qualquer conclusão sobre agente envolvido. Além disso, a alta soroprevalência de E. canis em cães e a evidência de anticorpos anti-Ehrlichia sp. em humanos, sugere que os casos de erliquiose humana no Brasil possam ser causados por E. canis ou outra espécie intimamente relacionada.The aims of this study were to determine the seroprevalence of Ehrlichia spp. and risk factors for exposure in a restricted population of dogs, horses, and humans highly exposed to tick bites in a Brazilian rural settlement using a commercial ELISA rapid test and two indirect immunofluorescent assays (IFA) with E. canis and E. chaffeensis crude antigens. Serum samples from 132 dogs, 16 horses and 100 humans were used. Fifty-six out of 132 (42.4%) dogs were seropositive for E. canis. Dogs > one year were more likely to be seropositive for E. canis than dogs ≤ one year (p = 0.0051). Ten/16 (62.5%) and 8/16 (50%) horses were seropositive by the commercial ELISA and IFA, respectively. Five out of 100 (5%) humans were seropositive for E. canis and E. chaffeensis. Rhipicephalus sanguineus (n = 291, 97.98%) on dogs and Amblyomma cajennense (n = 25, 96.15%) on horses were the most common ticks found. In conclusion, anti-Ehrlichia spp. antibodies were found in horses; however, the lack of a molecular characterization precludes any conclusion regarding the agent involved. Additionally, the higher seroprevalence of E. canis in dogs and the evidence of anti-Ehrlichia spp. antibodies in humans suggest that human cases of ehrlichiosis in Brazil might be caused by E. canis, or other closely related species

Anthropometric cranial measurements of normal newborn in Sergipe - Northeast of Brazil

O estudo antropométrico do crânio é fundamental para a avaliação do recém-nascido. As medidas antropométricas usadas na atualidade são baseadas em resultados obtidos há mais de cinco décadas, os quais não são capazes de determinar um padrão nacional em decorrência de possíveis influências de algumas etnias. Realizamos estudo descritivo analítico em uma Maternidade em Aracaju-SE, com medidas de perímetro cefálico, distancia biauricular e anteroposterior, índice cefálico e medida da fontanela; foram examinadas 450 recém-nascidos com idade gestacional entre 37 e 42 semanas; 49,3% era do gênero masculino e 50,6% do feminino. O perímetro cefálico variou entre 30,0 cm e 39,8 cm com média de 34,14±2,48 com P50 34 cm. O índice cefálico variou entre 0,69 e 1,13 com média de 0,98±0,06 com P50 1. Foi feito uma comparação entre os estudos estrangeiros e brasileiros; o recém-nascido sergipano aproxima-se mais dos resultados obtidos nos estudos da região sudeste do que dos resultados da região nordeste, geograficamente semelhante. A possibilidade de influencias étnicas foi levantada, como também a necessidade de realizar um estudo multicêntrico para criar um perfil antropométrico do recém-nascido brasileiro. _________________________________________________________________________________________ ABSTRACT: The anthropometric mesureaments of the skull is essential for the evaluation of the newborn. The anthropometrics measureaments utilized at the present time are based in the results obtained for more than five decades, which are not able to determine a national pattern mostly likely due to some ethnic influences. We carried out an analytical descriptive study in a maternity hospital in Aracaju-Sergipe, Northeast of Brazil. Measurements of cephalic perimeter, biauricular and anteroposterior distances, cephalic index and fontanels were obtained from 450 newborns with gestacional age from 37 and 42 weeks; 49.3% were male and 50.6% female. The cephalic perimeter ranged from 30.0 cm to 39.8 cm with mean value of 34.14±2.48 P50 34 cm, and cephalic index ranged from 0.69 and 1.13 with mean value of 0.98±0.06 P50 1. A comparison was made between brazilian and foreign studies; the results of the newborn from Sergipe were closer to results obtained in the southeast region than the ones obtained in the northeast region itself. The possibility of ethnical influences was raised as well as the need to design a multicentric study in order to define an anthropometric profile of the brazilian newborn

Xylella fastidiosa : An in vivo system to study possible survival strategies within citrus xylem vessels based on global gene expression analysis

Abstract Xylella fastidiosa inhabits the plant xylem, a nutrient-poor environment, so that mechanisms to sense and respond to adverse environmental conditions are extremely important for bacterial survival in the plant host. Although the complete genome sequences of different Xylella strains have been determined, little is known about stress responses and gene regulation in these organisms. In this work, a DNA microarray was constructed containing 2,600 ORFs identified in the genome sequencing project of Xylella fastidiosa 9a5c strain, and used to check global gene expression differences in the bacteria when it is infecting a symptomatic and a tolerant citrus tree. Different patterns of expression were found in each variety, suggesting that bacteria are responding differentially according to each plant xylem environment. The global gene expression profile was determined and several genes related to bacterial survival in stressed conditions were found to be differentially expressed between varieties, suggesting the involvement of different strategies for adaptation to the environment. The expression pattern of some genes related to the heat shock response, toxin and detoxification processes, adaptation to atypical conditions, repair systems as well as some regulatory genes are discussed in this paper. DNA microarray proved to be a powerful technique for global transcriptome analyses. This is one of the first studies of Xylella fastidiosa gene expression in vivo which helped to increase insight into stress responses and possible bacterial survival mechanisms in the nutrient-poor environment of xylem vessels

Hysteretic Behavior of Proprotein Convertase 1/3 (PC1/3)

The proprotein convertases (PCs) are calcium-dependent proteases responsible for processing precursor proteins into their active forms in eukariotes. The PC1/3 is a pivotal enzyme of this family that participates in the proteolytic maturation of prohormones and neuropeptides inside the regulated secretory pathway. In this paper we demonstrate that mouse proprotein convertase 1/3 (mPC1/3) has a lag phase of activation by substrates that can be interpreted as a hysteretic behavior of the enzyme for their hydrolysis. This is an unprecedented observation in peptidases, but is frequent in regulatory enzymes with physiological relevance. The lag phase of mPC1/3 is dependent on substrate, calcium concentration and pH. This hysteretic behavior may have implications in the physiological processes in which PC1/3 participates and could be considered an additional control step in the peptide hormone maturation processes as for instance in the transformation of proinsulin to insulin