The secretion of bacterial virulence factors and flagellar components requires the assistance of specific type III and flagellar chaperones. Standard computational annotation of the genome of Xanthomonas axonopodis pv citri, a plant pathogen that causes citrus canker, initially did not identify any genes belonging to these chaperone categories since the primary sequence homology between them was very low. However, in a search for hypothetical proteins with characteristics similar to these chaperones, we have now identified 30 chromosomal and 10 plasmidial potential genes encoding chaperones belonging to types III/IV, and flagellar secretion systems in this organism. The significance of these findings is discussed.

CONTEXTO: Neste trabalho foi estudada a alteração molecular em um paciente brasileiro de 72 anos com talassemia beta homozigótica com evolução clínica intermediária, esplenectomizado e necessitando de transfusões ocasionais. Os dados hematológicos mostravam anemia microcítica e hipocrômica (Hemoglobina = 7,9 g/dl, Volume Corpuscular Médio = 76fl, Hemoblobina Corpuscular Média = 26 pg) e a eletroforese de hemoglobina revelou Hemoglobina Fetal = 14,2%, Hemoglobina A2 = 6,2% e Hemoglobina A = 79,4%. OBJETIVO: Identificar as duas mutações envolvendo um paciente com sintomas de talassemia beta intermediária. TIPO DE ESTUDO: Investigação molecular das possíveis mutações responsáveis pelo quadro clínico descrito. LOCAL: Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, São Paulo, Brasil. PROCEDIMENTOS: Após a extração de DNA do sangue deste paciente, foi feita reação de polimerase em cadeia (polymerase chain reaction, PCR) utilizando cinco pares de primers que amplificaram éxons e a região promotora do gene da globina beta. O produto da amplificação foi seqüenciado e os cromatogramas, analisados por programas de computador (Phred, Phrap e Consed). RESULTADOS: Foram encontradas duas mutações responsáveis pela doença;-101 (C > T) e códon 39 (C > T). CONCLUSÕES: Este caso representa a primeira descrição da mutação 101 (C > T) na população brasileira e está associado a evolução clínica benigna.

CONTEXT: We verified molecular alterations in a 72-year-old Brazilian male patient with a clinical course of homozygous beta-thalassemia intermedia, who had undergone splenectomy and was surviving without regular blood transfusions. The blood cell count revealed microcytic and hypochromic anemia (hemoglobin = 6.5 g/dl, mean cell volume = 74 fl, mean cell hemoglobin = 24 pg) and hemoglobin electrophoresis showed fetal hemoglobin = 1.3%, hemoglobin A2 = 6.78% and hemoglobin A = 79.4%. OBJECTIVE: To identify mutations in a patient with the symptoms of beta-thalassemia intermedia. DESIGN: Molecular inquiry into the mutations possibly responsible for the clinical picture described. SETTING: The structural molecular biology and genetic engineering center of the Universidade Estadual de Campinas, Campinas, Brazil. PROCEDURES: DNA extraction was performed on the patient's blood samples. The polymerase chain reaction (PCR) was done using five specific primers that amplified exons and the promoter region of the beta globin gene. The samples were sequenced and then analyzed via computer programs. RESULTS: Two mutations that cause the disease were found: -101 (C > T) and codon 39 (C > T). CONCLUSIONS: This case represents the first description of 101 (C > T) mutation in a Brazilian population and it is associated with a benign clinical course.