RESUMO
We have identified a novel family of five 3' co-terminal transcripts in murine cytomegalovirus (MCMV) arranged in a tail-to-tail orientation with respect to the MCMV glycoprotein H (gH) gene M75. They share the same exon 2 sequence but possess different exon 1 sequences. Two of these spliced transcripts (M73) encode the MCMV homolog of glycoprotein N (gN) entirely within exon 1. Two other transcripts designated M73.5 encode a previously described virion glycoprotein gp24 that shares its first 20 amino acids with gN, but which has another 64 amino acids encoded within exon 2. The fifth transcript, designated m60, has an 80-bp exon 1 near the MCMV oriLyt region 10.8 kb upstream of exon 2. Both MCMV M73.5 and m60 encode type II glycoproteins expressed at the cell surface. Their shared exon 2 coding sequences likely represent the highly conserved region of an as yet unidentified betaherpesvirus-specific glycoprotein species.
Assuntos
Glicoproteínas/genética , Muromegalovirus/genética , Proteínas Estruturais Virais/genética , Células 3T3 , Processamento Alternativo , Sequência de Aminoácidos , Animais , Células COS , DNA Complementar/química , DNA Complementar/isolamento & purificação , Éxons , Glicoproteínas/biossíntese , Glicoproteínas/química , Camundongos , Dados de Sequência Molecular , Splicing de RNA , RNA Mensageiro/genética , Alinhamento de Sequência , Transfecção , Proteínas Estruturais Virais/biossíntese , Proteínas Estruturais Virais/química , Vírion/genéticaRESUMO
The purpose of this study was to investigate genetic variation in the anaerobic intestinal spirochaete Brachyspira aalborgi by partial sequencing of the 16S rRNA and NADH oxidase genes. The spirochaete is poorly cultivable; hence, only six isolates were available for analysis. Additional sequences were amplified from DNA extracted from fixed colorectal biopsies from 26 patients with histological evidence of intestinal spirochaetosis, and from the faeces of six non-human primates (NHP). Multiple biopsies from sites along the large intestine were tested from three of the 26 patients. Sequences from two biopsies were closely related to those of the spirochaete Brachyspira pilosicoli. Eight B. aalborgi-like 16S rDNA sequences were generated from the biopsies from the other 24 patients, and four from the NHP faeces. The B. aalborgi 16S rDNA sequences were divided into three clusters, 1, 2 and 4, with individual sequence similarities to the type strain ranging from 97.49 to 100 %. All human isolates of B. aalborgi were located in cluster 1, as was the sequence of the so-called 'Brachyspira ibaraki'. All four 16S rDNA sequences from the NHP faeces and the two NHP isolates of B. aalborgi were located in cluster 4, which was distinct. Cluster 4 may represent a novel Brachyspira species. Evidence for multiple strains of B. aalborgi or other Brachyspira species was found in biopsies from two patients. In the three individuals from whom multiple biopsies were amplified, the sequences at each intestinal site were the same, indicating the presence of one dominant strain.
Assuntos
Brachyspira/genética , Variação Genética , Complexos Multienzimáticos/genética , NADH NADPH Oxirredutases/genética , RNA Ribossômico 16S/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Sequência de Bases , Brachyspira/classificação , Brachyspira/enzimologia , Portador Sadio/microbiologia , Criança , Análise por Conglomerados , DNA Bacteriano/química , DNA Ribossômico/química , Fezes/microbiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , Primatas , Infecções por Spirochaetales/microbiologiaRESUMO
The purpose of this study was to investigate the presence of the anaerobic intestinal spirochetes Brachyspira aalborgi and Brachyspira pilosicoli in the feces of captive nonhuman primates (n = 35) from 19 species housed at the Zoological Gardens, Perth, Western Australia. Both spirochete species are known to infect human beings. DNA was extracted from freshly collected feces with a commercially available QIAamp DNA stool minikit and subjected to PCR protocols amplifying portions of the 16S rRNA genes of the two spirochete species. The feces were also subjected to selective culture for the spirochetes. Subsequently, feces from 62 other captive animals or birds representing 39 species at the zoo were examined by PCR to determine whether they were reservoirs of infection. Six fecal samples from individuals from four primate species (two vervet monkeys, two Tonkean macaques, one Japanese macaque, and one hamadryas baboon) tested positive in the B. aalborgi PCR. B. aalborgi was not detected by PCR in any of the other animal or bird species tested, and B. pilosicoli was not detected in the primates or any of the other animals or birds. B. aalborgi was isolated from both PCR-positive vervet monkeys. This is the first time that B. aalborgi has been isolated from nonhuman primates and the first time that it has been isolated from the feces of any species.
