| identification of a new human dna virus (ttv-like mini virus, tlmv) intermediately related to tt virus and chicken anemia virus. | tt virus (ttv) is the only known human virus with single-stranded circular dna, with a possible but yet unclear relationship to chicken anemia virus (cav) of the family circoviridae. here we report a new human virus resembling ttv and cav, designated ttv-like mini virus (tlmv). this non-enveloped virus was smaller (< 30 nm) but had a similar density (1.31-1.34 g/ml in cscl) to ttv, when a tlmv/ttv-coinfected plasma was analyzed. full-length sequencing revealed that the tlmv genome was a circular ... | 2000 | 10881684 |
| full or near full length nucleotide sequences of tt virus variants (types sanban and yonban) and the tt virus-like mini virus. | tt virus (ttv) is a common virus and consists of many genotypes and variants. in addition, there exists a virus which both differs greatly from and retains a considerable resemblance to ttv, such as the ttv-like mini virus (tlmv) as we reported previously. here we report the near full length genomic sequences of 4 isolates of a new variant of ttv (designated yonban) along with the full length sequences of 2 isolates of the ttv-sanban lineage and 7 isolates of the tlmv species derived from human ... | 2000 | 10971131 |
| genetic analysis of full-length genomes and subgenomic sequences of tt virus-like mini virus human isolates. | the phylogenetic relationship between the complete genomic sequences of ten japanese and one french isolate of tt virus-like mini virus (tlmv) was investigated. analysis of the variability of the nucleotide sequences and the detection of signature patterns for overlapping genes suggested that orfs 1 and 2 are probably functional. however, this was not the case for a putative third orf, orf3. throughout the viral genome, several nucleotide or amino acid motifs that are conserved in circoviruses s ... | 2001 | 11161277 |
| [molecular cloning and sequencing of 5' non-coding region of ttv-like mini virus]. | to investigate the ttv- like mini virus (tlmv) infection in chinese patients with non a-g hepatitis and to analyse sequence of 5' non-coding region (5'ncr)of tlmv. | 2000 | 11498688 |
| high detection rates of ttv-like mini virus sequences in sera from brazilian blood donors. | tt virus (ttv) is an unenveloped virus with a single-stranded, circular dna genome of 3,818-3,853 nucleotides (nt) that infects humans and non-human primates. recently, the existence of a novel human virus, ttv-like mini virus (tlmv), that shows a genetic organization similar to that of ttv, but with smaller virion particle and genome, was proposed [takahashi et al. (2000) archives of virology 145:979-993]. to date, no information is available with respect to the prevalence and pathogenicity of ... | 2001 | 11505464 |
| genomic and evolutionary characterization of tt virus (ttv) in tupaias and comparison with species-specific ttvs in humans and non-human primates. | tt virus (ttv) was recovered from the sera of tupaias (tupaia belangeri chinensis) by pcr using primers derived from the noncoding region of the human ttv genome, and its entire genomic sequence was determined. one tupaia ttv isolate (tbc-ttv14) consisted of only 2199 nucleotides (nt) and had three open reading frames (orfs), spanning 1506 nt (orf1), 177 nt (orf2) and 642 nt (orf3), which were in the same orientation as the orfs of the human prototype ttv (ta278). orf3 was presumed to arise from ... | 2001 | 11514713 |
| existence of tt virus dna and ttv-like mini virus dna in infant cord blood: mother-to-neonatal transmission. | the route of transmission of tt virus (ttv) was studied by examining the existence of ttv dna in different body fluids from the new born infants and their mothers. a total of 52 pregnant women with normal serum alanine aminotransferase levels were enrolled in this study. ttv dna was examined using a polymerase chain reaction method using takahashi's primers which can detect all genotypes of ttv and okamoto's primers which detect only some of the genotypes of ttv. ttv dna was detected in the sera ... | 2001 | 11673113 |
| molecular epidemiology of ttv-like mini virus in norway. | tt virus (ttv), the first human circovirus to be discovered, appears to be present in most people; less is known about the prevalence of the related ttv-like mini virus (tlmv). a sensitive nested pcr, specific for tlmv, detected the virus in 48% of 201 sera (norwegian blood donors) previously found to have a 90% prevalence of ttv. more samples were either positive for both or negative for both viruses than what would have been expected from a random distribution (p = 0.08). sequence analysis rev ... | 2002 | 11855630 |
| ttv, a new human virus with single stranded circular dna genome. | tt virus (ttv) was found in 1997 from a hepatitis patient without virus markers. however, the real impact of ttv on liver diseases remains uncertain to date. due to the lack of suitable cell systems to support the growth of ttv, the biology of ttv is still obscure. this review tries to summarise the current status of ttv on aspects other than the taxonomic diversity of ttv. ttv was the first human virus with a single stranded circular dna genome. ttv was considered to be a member of circoviridae ... | 2002 | 11987140 |
| real-time pcr methods for independent quantitation of ttv and tlmv. | there is considerable interest in the possible clinical effects of the human circoviruses tt virus (ttv) and ttv-like mini virus (tlmv). most people appear to have at least one of these viruses replicating actively in their bodies, thus mere correlation of the presence of virus and disease states are probably less informative than a quantitative analysis of viraemia. real-time pcr based methods, with either sybr green or taqman probe, designed to quantitate selectively ttv and tlmv are described ... | 2002 | 12020793 |
| high genetic diversity revealed by the study of tlmv infection in french hemodialysis patients. | tt virus-like minivirus (tlmv) was recently discovered as a human circovirus. little is known about its natural history and molecular epidemiology. a study of tlmv infection is described in a population of french hemodialysis patients. tlmv dna was tested by seminested pcr system located in the noncoding region in 81 patients divided into seven groups according to the origin of their renal disease. quantitation of tlmv dna in serum was carried out. sequences from 28 patients were compared with 4 ... | 2002 | 12116016 |
| chicken anemia virus vp2 is a novel dual specificity protein phosphatase. | the function of viral protein 2 (vp2) of the immunosuppressive circovirus chicken anemia virus (cav) has not yet been established. we show that the cav vp2 amino acid sequence has some similarity to a number of eukaryotic, receptor, protein-tyrosine phosphatase (ptpase) alpha proteins as well as to a cluster of human tt viruses within the sanban group. to investigate if cav vp2 functions as a ptpase, purified glutathione s-transferase (gst)-vp2 fusion protein was assayed for ptpase activity usin ... | 2002 | 12151384 |
| serum concentrations of tt virus and tt virus-like mini virus in patients developing aids. | changes in viraemia of two chronically replicating circoviruses, tt virus (ttv) and ttv-like mini virus (tlmv), were investigated in patients developing hiv-related immune deficiency. in a few cases, episodes of a considerable increase in viraemia were observed, but in most patients there were no discernible increases as immune deficiency progressed. the deterioration of immune function associated with aids did not by itself have any obvious effect on ttv and tlmv. | 2002 | 12172090 |
| mixed infections of adults and children with multiple ttv-like mini virus isolates. | testing of the dna of ttv-like mini virus (tlmv) was done with serum samples obtained from 184 patients (children and adults) who visited different outpatient clinics at a university hospital in florianopolis, south of brazil. tlmv dna was detected by pcr primers from the non-coding region of the genome. a global tlmv prevalence of 78% was found (94% among children below 11 years). pcr products from three serum samples (patients a-c) were cloned, and the sequences with a length of 201-227 nucleo ... | 2002 | 12210422 |
| effect of immune modulation on tt virus (ttv) and ttv-like-mini-virus (tlmv) viremia. | the present study was designed to investigate how two chronically replicating viruses, tt virus (ttv) and ttv-like mini virus (tlmv), interact with host defence systems. successive serum samples from three groups of subjects, undergoing modifications of their antiviral defence, were tested by real-time pcr to measure changes in viral titers, and by sequence analyses to indicate whether increases in viremia could be attributed to infection with an unfamiliar strain: 1) in patients receiving immun ... | 2003 | 12629661 |
| distribution of tt virus (ttv), ttv-like minivirus, and related viruses in humans and nonhuman primates. | tt virus (ttv) and ttv-like minivirus (tlmv) are small dna viruses with single-stranded, closed circular, antisense genomes infecting man. despite their extreme sequence heterogeneity (>50%), a highly conserved region in the untranslated region (utr) allows both viruses to be amplified by polymerase chain reaction (pcr). ttv/tlmv infection was detected in 88 of 100 human plasma samples; amplified sequences were differentiated into ttv and tlmv by analysis of melting profiles, showing that both v ... | 2003 | 12642105 |
| human circoviruses. | tt virus (ttv) and ttv-like mini virus (tlmv) represent the first described human circoviruses. they do not show significant sequence homology with any other animal circovirus identified to date. they are both detected with high prevalences in various body fluids. the spread mode may include the parenteral way, the transmission by saliva droplets and the fecal-oral route. genetic variability within a viral group is high and the co-infection by distinct viral strains is common in a given individu ... | 2004 | 14741121 |
| progression towards aids leads to increased torque teno virus and torque teno minivirus titers in tissues of hiv infected individuals. | torque teno virus (ttv) and torque teno minivirus (ttmv) are highly prevalent in the general population and although no disease has been associated with these viruses yet, co-infections with other pathological viruses are frequent. both viruses are extremely heterogeneous, especially for dna viruses, and the role of the immune system in controlling the infections has yet to be established. in this study the ttv/ttmv viral loads in hiv positive tissues have been investigated for the first time. t ... | 2007 | 17133553 |
| torque teno virus (ttv): current status. | torque teno virus (ttv), currently classified into the family circoviridae, genus anellovirus, was first found in a patient with non-a-e hepatitis. ttv has a single stranded circular dna of approximately 3.8 kb. ttvs are extraordinarily diverse, spanning five groups including sanban and sen viruses. torque teno mini virus (ttmv) with approximately 2.9 kb genome also has wide variants. recently, two related 2.2- and 2.6-kb species joined this community. recombinations between variants are frequen ... | 2007 | 17146841 |
| identification and genomic characterization of a novel human torque teno virus of 3.2 kb. | in the process of searching for the recently described small anelloviruses 1 and 2 (savs) with the genomic dna length of 2.2 or 2.6 kb in human sera, we isolated a novel virus with its genomic organization resembling those of torque teno virus (ttv) of 3.8-3.9 kb and torque teno mini virus (ttmv) of 2.8-2.9 kb. the entire genomic sequence of three isolates (md1-032, md1-073 and md2-013), which comprised 3242-3253 bases and exhibited 76-99 % identities with the savs within the overlapping sequenc ... | 2007 | 17554026 |
| analysis of the entire genomes of fifteen torque teno midi virus variants classifiable into a third group of genus anellovirus. | recently, we identified a novel human virus with a circular dna genome of 3.2 kb, tentatively designated as torque teno midi virus (ttmdv), with a genomic organization resembling those of torque teno virus (ttv) of 3.8-3.9 kb and torque teno mini virus (ttmv) of 2.8-2.9 kb. to investigate the extent of genomic variability of ttmdv genomes, the full-length sequence was determined for 15 ttmdv isolates obtained from viremic individuals in japan. the 15 ttmdv isolates comprised 3175-3230 bases and ... | 2007 | 17712598 |
| circular genomes related to anelloviruses identified in human and animal samples by using a combined rolling-circle amplification/sequence-independent single primer amplification approach. | a combined rolling-circle amplification (rca) and sequence-independent single primer amplification (sispa) approach was applied to four samples of human plasma and one sample of saliva from a cat. this approach permitted the characterization of nine anelloviruses. most of them were identified as highly divergent strains that were classified into species of the genus anellovirus. the smallest anellovirus described so far in humans was characterized (2posma, 2002 nt; 'small anellovirus' species). ... | 2007 | 17872521 |
| development of pcr assays with nested primers specific for differential detection of three human anelloviruses and early acquisition of dual or triple infection during infancy. | we recently identified a novel human virus classifiable into a third group in the genus anellovirus, tentatively designated torque teno midi virus (ttmdv), with a circular dna genome of 3.2 kb and genomic organization resembling those of torque teno virus (ttv) (3.8 to 3.9 kb) and torque teno mini virus (ttmv) (2.8 to 2.9 kb). ttmdv was characterized by extreme genetic diversity similar to the ttv and ttmv genomes. taking advantage of universal and virus species-specific primers derived from a h ... | 2008 | 18094127 |
| analysis of the entire genomes of torque teno midi virus variants in chimpanzees: infrequent cross-species infection between humans and chimpanzees. | humans are frequently infected with three anelloviruses which have circular dna genomes of 3.6-3.9 kb [torque teno virus (ttv)], 2.8-2.9 kb [torque teno mini virus (ttmv)] and 3.2 kb [a recently discovered anellovirus named torque teno midi virus (ttmdv)]. unexpectedly, human ttmdv dna was not detectable in any of 74 chimpanzees tested, although all but one tested positive for both human ttv and ttmv dna. using universal primers for anelloviruses, novel variants of ttmdv that are phylogeneticall ... | 2009 | 19141443 |
| history of discoveries and pathogenicity of tt viruses. | since 1997, groups of novel nonenveloped dna viruses with a circular, single-stranded (negative sense) dna genome of 3.6-3.9 kb, 3.2 kb, or 2.8-2.9 kb in size have been discovered and designated torque teno virus (ttv), torque teno midi virus (ttmdv), and torque teno mini virus (ttmv), respectively, in the floating genus anellovirus. these three anelloviruses frequently and ubiquitously infect humans, and the infections are characterized by lifelong viremia and great genetic variability. althoug ... | 2009 | 19230554 |
| tt viruses in animals. | infection with tt virus (torque teno virus, ttv), a small, nonenveloped virus with a circular, single-stranded dna genome classified in the floating genus anellovirus, is not restricted to humans. using highly conserved primers derived from the untranslated region of the human ttv genome, a variety of ttv-like viruses have been found circulating in nonhuman primates such as chimpanzees, macaques, and tamarins. ttv variants in nonhuman primates are species-specific, although some genetic groups o ... | 2009 | 19230556 |
| chicken anemia virus. | chicken anemia virus (cav), the only member of the genus gyrovirus of the circoviridae, is a ubiquitous pathogen of chickens and has a worldwide distribution. cav shares some similarities with torque teno virus (ttv) and torque teno mini virus (ttmv) such as coding for a protein inducing apoptosis and a protein with a dual-specificity phosphatase. in contrast to ttv, the genome of cav is highly conserved. another important difference is that cav can be isolated in cell culture. cav produces a si ... | 2009 | 19230563 |
| quantitative detection of porcine torque teno virus in porcine circovirus-2-negative and porcine circovirus-associated disease-affected pigs. | torque teno virus (ttv) is a recently identified virus that has a wide range of host tropisms from humans to shrews. human ttv and torque teno mini virus are distributed worldwide, and their high prevalence in human populations has been reported. pigs have their own species-specific ttv, and like human ttv, a high prevalence of porcine ttv also has been reported. despite its high prevalence, the role of ttv-related disease or syndrome in humans and pigs has not been determined. in the swine indu ... | 2010 | 20224089 |
| transfusion transmission of highly prevalent commensal human viruses. | anellovirus species torque teno virus (ttv), torque teno mini virus (ttmv), and torque teno midi virus (ttmdv) and flavivirus gbv-c are highly prevalent and genetically diverse chronic human viral infections that have not yet been associated with disease. | 2010 | 20497515 |
| torque teno mini virus infection and multiple sclerosis. | abstract multiple sclerosis (ms) is a disease of young adults which is characterized by autoimmune demyelination of the central nervous system. interaction of genetics and environmental factors are required to cause ms. among the proposed environmental factors for ms, viral infections are thought to play a predominant role in the pathogenesis of the disease. the torque teno mini virus (ttmv), which has recently been shown to infect humans, is a member of circoviridae, and has a circular dna with ... | 2011 | 21545307 |
| sequence analysis of a torque teno canis virus isolated in china. | in the present study, a total of 158 fecal samples were collected from diarrheal dogs younger than 1 year old in pet clinic in china. 20 specimens (20/158, 13%) were positive for torque teno canis virus dna using detection pcr. one representative positive isolate designated ldl was randomly selected, cloned and sequenced. the complete genome of the ldl chinese strain was 2799 nucleotides in length and contains three open reading frames (orfs), which encode 576 (orf1), 101 (orf2), and 243 (orf3) ... | 2011 | 21645561 |