RESUMO
Chlamydia are obligate intracellular eubacteria that are phylogenetically separated from other bacterial divisions. C. trachomatis and C. pneumoniae are both pathogens of humans but differ in their tissue tropism and spectrum of diseases. C. pneumoniae is a newly recognized species of Chlamydia that is a natural pathogen of humans, and causes pneumonia and bronchitis. In the United States, approximately 10% of pneumonia cases and 5% of bronchitis cases are attributed to C. pneumoniae infection. Chronic disease may result following respiratory-acquired infection, such as reactive airway disease, adult-onset asthma and potentially lung cancer. In addition, C. pneumoniae infection has been associated with atherosclerosis. C. trachomatis infection causes trachoma, an ocular infection that leads to blindness, and sexually transmitted diseases such as pelvic inflammatory disease, chronic pelvic pain, ectopic pregnancy and epididymitis. Although relatively little is known about C. trachomatis biology, even less is known concerning C. pneumoniae. Comparison of the C. pneumoniae genome with the C. trachomatis genome will provide an understanding of the common biological processes required for infection and survival in mammalian cells. Genomic differences are implicated in the unique properties that differentiate the two species in disease spectrum. Analysis of the 1,230,230-nt C. pneumoniae genome revealed 214 protein-coding sequences not found in C. trachomatis, most without homologues to other known sequences. Prominent comparative findings include expansion of a novel family of 21 sequence-variant outer-membrane proteins, conservation of a type-III secretion virulence system, three serine/threonine protein kinases and a pair of parologous phospholipase-D-like proteins, additional purine and biotin biosynthetic capability, a homologue for aromatic amino acid (tryptophan) hydroxylase and the loss of tryptophan biosynthesis genes.
Assuntos
Proteínas de Bactérias/genética , Chlamydia trachomatis/genética , Chlamydophila pneumoniae/genética , Genoma Bacteriano , Sequência de Aminoácidos , Proteínas de Bactérias/metabolismo , Chlamydia trachomatis/metabolismo , Chlamydia trachomatis/patogenicidade , Chlamydophila pneumoniae/metabolismo , Chlamydophila pneumoniae/patogenicidade , Sequência Conservada , Enzimas/genética , Enzimas/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Dados de Sequência Molecular , Óperon , Homologia de Sequência de Aminoácidos , Triptofano/biossínteseRESUMO
The scarcity of usable nitrogen frequently limits plant growth. A tight metabolic association with rhizobial bacteria allows legumes to obtain nitrogen compounds by bacterial reduction of dinitrogen (N2) to ammonium (NH4+). We present here the annotated DNA sequence of the alpha-proteobacterium Sinorhizobium meliloti, the symbiont of alfalfa. The tripartite 6.7-megabase (Mb) genome comprises a 3.65-Mb chromosome, and 1.35-Mb pSymA and 1.68-Mb pSymB megaplasmids. Genome sequence analysis indicates that all three elements contribute, in varying degrees, to symbiosis and reveals how this genome may have emerged during evolution. The genome sequence will be useful in understanding the dynamics of interkingdom associations and of life in soil environments.
Assuntos
Genoma Bacteriano , Análise de Sequência de DNA , Sinorhizobium meliloti/genética , Simbiose/genética , Aderência Bacteriana , Proteínas de Bactérias/genética , Proteínas de Transporte/genética , Cromossomos Bacterianos/genética , Biologia Computacional , Elementos de DNA Transponíveis , Metabolismo Energético/genética , Evolução Molecular , Duplicação Gênica , Genes Bacterianos , Genes Essenciais , Genes Reguladores , Medicago sativa/microbiologia , Nitrogênio/metabolismo , Fixação de Nitrogênio/genética , Plasmídeos , Polissacarídeos Bacterianos/genética , Replicon , Rhizobiaceae/genética , Sinorhizobium meliloti/fisiologiaRESUMO
In situ hybridization experiments with the use of recombinant herpes simplex virus type 1 DNA as probes have detected virus-specific RNA in herpes simplex virus type 1-transformed Syrian hamster cell lines. The relatively most abundant virus transcripts hybridized to the herpes simplex virus type 1 EcoRI-F fragment at map position 0.32-0.42.
Assuntos
Transformação Celular Neoplásica , Neoplasias Experimentais/microbiologia , RNA Viral/genética , Simplexvirus/genética , Animais , Linhagem Celular , Cricetinae , Embrião de Mamíferos , Fibroblastos , Metástase Neoplásica , Neoplasias Experimentais/patologia , RNA Viral/isolamento & purificaçãoRESUMO
Infection of CD-1 mouse embryo fibroblast(s) (MEF) with infectious bovine rhinotracheitis virus (IBRV) strain HMC resulted in persistent infection and subsequent transformation of these cells. IBRV-transformed MEF cultures consisted of short fibroblastoid cells, and IBRV-specific membrane and intracellular antigens were detectable in early in vitro passages by indirect imunofluorescence (IF) techniques. The presence of IBRV genetic information was confirmed in IF-positive and IF-negative cells by in situ hybridization. IBRV-transformed MEF induced fibrosarcomas in athymic nude mice given sc transplants. Infectious virus could not be rescued from the transformed cells or from tumor cells by cocultivation with rabbit kidney cells, by treatment with 5-iodo-2'-deoxyuridine, or by UV irradiation. Nontransformed control cells did not survive more than 10 in vitro passages and did not induce tumors when transplanted to athymic nude mice. These observations represent new data concerning the mouse cell-transforming potential of IBRV and confirm the presence of at least part of the virus genome in the transformants.
Assuntos
Transformação Celular Neoplásica/patologia , Transformação Celular Viral , Herpesvirus Bovino 1 , Animais , Antígenos de Neoplasias/análise , Antígenos Virais/imunologia , Transformação Celular Neoplásica/ultraestrutura , Células Cultivadas , Embrião de Mamíferos , Fibrossarcoma/patologia , Herpesvirus Bovino 1/genética , Herpesvirus Bovino 1/imunologia , Camundongos , Camundongos Nus , Transplante de Neoplasias , Neoplasias Experimentais/microbiologia , Neoplasias Experimentais/patologiaRESUMO
A short segment of the herpes simplex virus (HSV) DNA proximal IRL region hybridized to two doublet bands of EcoRI-digested human cellular DNA. The hybridization was abolished neither by increasing stringency conditions nor by inclusion of guanine-rich DNA in the hybridization mixture. Thus, the hybridization appeared to represent authentic base sequence homology between HSV DNA and middle repetitive human DNA.
Assuntos
DNA Viral , DNA , Hibridização de Ácido Nucleico , Simplexvirus/genética , Enzimas de Restrição do DNA , Desoxirribonuclease EcoRI , Humanos , Homologia de Sequência do Ácido NucleicoRESUMO
Varicella-zoster virus (VZV) DNA exists principally as two isomers. Despite the presence of inverted repeats bounding the long sequence region, the unique long sequence, UL, is found in one (prototype) orientation in 95-98% of VZV DNA molecules and in the inverted orientation in only 2-5% of the molecules. In searching for an explanation for this disparity, we superinfected VZV-infected cells with herpes simplex virus type 1 or pseudorabies virus. Neither superinfecting virus produced a measurable change in the frequency of isomerization of the VZV DNA long sequence region.
Assuntos
DNA Viral , Herpesvirus Humano 3/genética , Sequência de Bases , Mapeamento Cromossômico , Enzimas de Restrição do DNA , Herpesvirus Humano 3/ultraestrutura , Sequências Repetitivas de Ácido NucleicoRESUMO
A small DNA fragment containing the simple sequence [GGC]10 from the long repeat of herpes simplex virus type 1 (HSV-1) DNA hybridized to cellular DNA and polyadenylated RNA from different mammalian species. The number and intensity of blot hybridization signals were increased in human compared with rodent and simian nucleic acids. The hybridization was blocked specifically by human 28S ribosomal DNA, which shares only the GGC repeats with the herpes simplex virus DNA. These data indicate that GGC repeats were common components of cellular DNA and were expressed in mRNA. Blot hybridization analysis of viral RNA from the HSV-1 gene regions encompassing the GGC repeats revealed abundant stable mRNAs from portions of the virus genome not previously analyzed in detail and indicated that the viral GGC sequence was not expressed in stable cytoplasmic mRNA.
Assuntos
DNA Viral/genética , DNA/genética , Hibridização de Ácido Nucleico , RNA Mensageiro/genética , Simplexvirus/genética , Animais , Cricetinae , Haplorrinos , Camundongos , Poli A/genética , RNA/genética , RNA Viral/genética , Sequências Repetitivas de Ácido Nucleico , Transcrição GênicaAssuntos
DNA , Dactinomicina , Polinucleotídeos , Nucleotídeos de Adenina , Sítios de Ligação , Fenômenos Químicos , Química , Crustáceos , Nucleotídeos de Citosina , DNA/análise , Nucleotídeos de Guanina , Matemática , Nucleotídeos/análise , Polímeros , Ribonucleases , Espectrofotometria , Nucleotídeos de UracilaAssuntos
Colífagos/análise , Genes , RNA Mensageiro/isolamento & purificação , RNA Viral/isolamento & purificação , Centrifugação com Gradiente de Concentração , DNA de Cadeia Simples , DNA Viral , Eletroforese em Gel de Poliacrilamida , Escherichia coli , Genética Microbiana , Microscopia Eletrônica , Conformação de Ácido Nucleico , Hibridização de Ácido Nucleico , Isótopos de FósforoAssuntos
Colífagos , Transcrição Gênica , Aberrações Cromossômicas , Mapeamento Cromossômico , DNA Viral , RNA Polimerases Dirigidas por DNA , Eletroforese em Gel de Poliacrilamida , Escherichia coli , Microscopia Eletrônica , Modelos Biológicos , Peso Molecular , Mutação , Hibridização de Ácido Nucleico , Isótopos de Fósforo , RNA Mensageiro , RNA ViralRESUMO
Herpes simplex virus (HSV) DNA sediments homogeneously on a neutral sucrose gradient but heterogeneously on an alkaline sucrose gradient. Several factors that may influence the alkaline sedimentation pattern of HSV DNA were examined: e.g., the host cell, cell density at time of infection, multiplicity of infection, and the starting material for HSV DNA purification (whether HSV-infected cells or cell-free virus). Based on alkaline sedimentation analysis, these factors appear to play little or no role in the amount of intact single-stranded HSV DNA observed.
Assuntos
DNA de Cadeia Simples/análise , DNA Viral/análise , Concentração de Íons de Hidrogênio , Simplexvirus/análise , Animais , Linhagem Celular , Transformação Celular Viral , Centrifugação com Gradiente de Concentração , Chlorocebus aethiops , Rim , Sacarose , Cultura de Vírus , Replicação ViralRESUMO
Fragments of varicella zoster virus DNA produced by EcoRI endonuclease cleavage were cloned in vector pACYC 184 and those produced by HindIII cleavage were cloned in pBR322. Restriction enzyme cleavage maps established by double digestion and blot hybridization showed that varicella zoster virus DNA has a Mr of 80 +/- 3 x 10(6) and exists as a population of two isomers.
Assuntos
Clonagem Molecular , DNA Recombinante/metabolismo , DNA Viral/genética , Herpesvirus Humano 3/genética , Enzimas de Restrição do DNA , Microscopia Eletrônica , Peso Molecular , Hibridização de Ácido Nucleico , PlasmídeosRESUMO
The DNAs of a varicella-zoster virus vaccine and its parental virus were compared by CsCl buoyant density centrifugation and restriction enzyme cleavage analysis. The varicella-zoster virus vaccine DNA showed a heterogeneous buoyant profile and altered restriction enzyme cleavage patterns. These changed properties are probably the result of the accumulation of virus containing defective varicella-zoster virus DNA during extensive cell culture passage of the vaccine virus.
Assuntos
DNA Viral/genética , Herpesvirus Humano 3/genética , Vacinas Virais/análise , Enzimas de Restrição do DNA , Herpesvirus Humano 3/imunologiaRESUMO
Cytoplasmic RNA was isolated from varicella-zoster virus (VZV)-infected cells. By oligo(dT)-cellulose chromatography, the RNA was separated into polyadenylated, poly (A)+, and nonpolyadenylated, poly (A)-, fractions. RNA blot hybridization was employed to detect and map VZV transcripts. As VZV infection cannot be coordinated, cytoplasmic RNA was isolated from VZV-infected cells when the cells showed extensive cytopathology. Therefore, while the VZV transcripts represented heterogeneous temporal classes, it may be assumed that late VZV RNA predominated. At least 41, and as many as 67 (depending on DNA probe overlap), VZV polyadenylated transcripts have been identified. Preliminary evidence for the presence of two VZV-specific nonpolyadenylated, cytoplasmic transcripts was observed.
Assuntos
Herpesvirus Humano 3/genética , RNA Mensageiro/genética , RNA Viral/genética , Mapeamento Cromossômico , DNA Viral/genética , Genes Virais , Poli A/genética , RNA/genética , RNA Neoplásico/genética , Transcrição GênicaRESUMO
Five minority populations of aberrant, varicella-zoster virus (VZV)-derived genomes were identified among the encapsidated DNAs obtained from the nuclear and cytoplasmic fractions of an in vitro infection initiated with a lyophilized sample of the BIKEN VZV vaccine (strain Oka). These were (i) VZV genomes, present within nuclear but not cytoplasmic viral capsids, which had been cleaved at a specific site within the short segment and which were, therefore, 3.15 megadaltons (approximately 4% of the VZV genome length) short of full length; (ii) highly deleted, repetitive VZV genomes which contained the errant cleavage site but not the usual VZV genome terminal sequences; (iii) VZV genomes into which multiples of 1 through 5 defective genome repeat units had been inserted into a homologous site; (iv) VZV genomes with additions of 0.1 or 0.18 megadaltons of DNA at both the terminal and internal ends of the short segment; and (v) VZV DNA which had lost the HindIII restriction site at map position 0.11.