RESUMO
The German Neurospora Genome Project has assembled sequences from ordered cosmid and BAC clones of linkage groups II and V of the genome of Neurospora crassa in 13 and 12 contigs, respectively. Including additional sequences located on other linkage groups a total of 12 Mb were subjected to a manual gene extraction and annotation process. The genome comprises a small number of repetitive elements, a low degree of segmental duplications and very few paralogous genes. The analysis of the 3218 identified open reading frames provides a first overview of the protein equipment of a filamentous fungus. Significantly, N.crassa possesses a large variety of metabolic enzymes including a substantial number of enzymes involved in the degradation of complex substrates as well as secondary metabolism. While several of these enzymes are specific for filamentous fungi many are shared exclusively with prokaryotes.
Assuntos
Genoma Fúngico , Neurospora crassa/genética , Mapeamento Cromossômico , Cromossomos Fúngicos/genética , DNA Fúngico/química , DNA Fúngico/genética , Bases de Dados de Ácidos Nucleicos , Internet , Fases de Leitura Aberta/genética , Filogenia , Análise de Sequência de DNARESUMO
Chlamydiae are the major cause of preventable blindness and sexually transmitted disease. Genome analysis of a chlamydia-related symbiont of free-living amoebae revealed that it is twice as large as any of the pathogenic chlamydiae and had few signs of recent lateral gene acquisition. We showed that about 700 million years ago the last common ancestor of pathogenic and symbiotic chlamydiae was already adapted to intracellular survival in early eukaryotes and contained many virulence factors found in modern pathogenic chlamydiae, including a type III secretion system. Ancient chlamydiae appear to be the originators of mechanisms for the exploitation of eukaryotic cells.
Assuntos
Evolução Biológica , Chlamydiales/classificação , Chlamydiales/genética , Genoma Bacteriano , Acanthamoeba/microbiologia , Animais , Proteínas de Bactérias/análise , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Membrana Celular/química , Parede Celular/química , Chlamydia/classificação , Chlamydia/genética , Chlamydia/metabolismo , Chlamydia/patogenicidade , Chlamydiales/metabolismo , Chlamydiales/patogenicidade , Chlamydophila/classificação , Chlamydophila/genética , Chlamydophila/metabolismo , Chlamydophila/patogenicidade , Transporte de Elétrons , Ordem dos Genes , Transferência Genética Horizontal , Genes Bacterianos , Dados de Sequência Molecular , Proteínas de Transporte de Nucleotídeos/metabolismo , Filogenia , Simbiose , Virulência , Fatores de Virulência/genética , Fatores de Virulência/metabolismoRESUMO
Helicobacter hepaticus causes chronic hepatitis and liver cancer in mice. It is the prototype enterohepatic Helicobacter species and a close relative of Helicobacter pylori, also a recognized carcinogen. Here we report the complete genome sequence of H. hepaticus ATCC51449. H. hepaticus has a circular chromosome of 1,799,146 base pairs, predicted to encode 1,875 proteins. A total of 938, 953, and 821 proteins have orthologs in H. pylori, Campylobacter jejuni, and both pathogens, respectively. H. hepaticus lacks orthologs of most known H. pylori virulence factors, including adhesins, the VacA cytotoxin, and almost all cag pathogenicity island proteins, but has orthologs of the C. jejuni adhesin PEB1 and the cytolethal distending toxin (CDT). The genome contains a 71-kb genomic island (HHGI1) and several genomic islets whose G+C content differs from the rest of the genome. HHGI1 encodes three basic components of a type IV secretion system and other virulence protein homologs, suggesting a role of HHGI1 in pathogenicity. The genomic variability of H. hepaticus was assessed by comparing the genomes of 12 H. hepaticus strains with the sequenced genome by microarray hybridization. Although five strains, including all those known to have caused liver disease, were indistinguishable from ATCC51449, other strains lacked between 85 and 229 genes, including large parts of HHGI1, demonstrating extensive variation of genome content within the species.