RESUMO
Arabinogalactan proteins (AGP) are a diverse family of proteoglycans associated with the cell surfaces of plants. AGP have been implicated in a wide variety of plant cell processes, including signaling in symbioses. This study investigates the existence of putative AGP in free-living cyanobacterial cultures of the nitrogen-fixing, filamentous cyanobacteria Nostoc punctiforme and Nostoc sp. strain LBG1 and at the symbiotic interface in the symbioses between Nostoc spp. and two host plants, the angiosperm Gunnera manicata (in which the cyanobacterium is intracellular) and the liverwort Blasia pusilla (in which the cyanobacterium is extracellular). Enzyme-linked immunosorbent assay, immunoblotting, and immunofluorescence analyses demonstrated that three AGP glycan epitopes (recognized by monoclonal antibodies LM14, MAC207, and LM2) are present in free-living Nostoc cyanobacterial species. The same three AGP glycan epitopes are present at the Gunnera-Nostoc symbiotic interface and the LM2 epitope is detected during the establishment of the Blasia-Nostoc symbiosis. Bioinformatic analysis of the N. punctiforme genome identified five putative AGP core proteins that are representative of AGP classes found in plants. These results suggest a possible involvement of AGP in cyanobacterial-plant symbioses and are also suggestive of a cyanobacterial origin of AGP.
Assuntos
Regulação Bacteriana da Expressão Gênica/fisiologia , Hepatófitas/microbiologia , Magnoliopsida/microbiologia , Mucoproteínas/metabolismo , Nostoc/metabolismo , Simbiose/fisiologia , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Simulação por Computador , Epitopos , Técnica Indireta de Fluorescência para Anticorpo , Regulação da Expressão Gênica de Plantas/fisiologia , Hepatófitas/metabolismo , Magnoliopsida/metabolismo , Modelos Biológicos , Mucoproteínas/genética , Nostoc/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismoRESUMO
Hepatitis B, formerly called serum hepatitis, is a disease of worldwide importance because of the extent of morbidity and mortality it inflicts on its victims, and the demands it imposes on the economic and medical resources of a country. The hepatitis B surface antigen (HBsAg) is the first serologic marker to appear following a hepatitis B viral infection. As the condition improves clinically, the titre falls and subsequently disappears (usually within six months). If the titre persists after six months the patient is likely to become a chronic carrier. HBsAg is the only serologic marker tested for in St. Vincent and the Grenadines. Testing for this marker began in 1986. This article presents the results analysed over the last five years. Based on the results of the population tested, future steps that should be taken to control the spread of the disease are recommended (AU)
