New Papovavirus Contaminating Shope Papillomata

Virome of high-altitude canine digestive tract and genetic characterization of novel viruses potentially threatening human health

The majority of currently emerging infectious illnesses are zoonotic infections, which have caused serious public health and economic implications. The development of viral metagenomics has helped us to explore unknown viruses. We collected 1,970 canine feces from Yushu and Guoluo in the plateau region of China for this study to do a metagenomics analysis of the viral community of the canine digestive tract. Our analysis identified 203 novel viruses, classified into 11 known families and 2 unclassified groups. These viruses include the hepatitis E virus, first identified in dogs, and the astrovirus, coronavirus, polyomavirus, and others. The relationship between the newly identified canine viruses and known viruses was investigated through the use of phylogenetic analysis. Furthermore, we demonstrated the cross-species transmission of viruses and predicted new viruses that may cause diseases in both humans and animals, providing technical support for the prevention and control of diseases caused by environmental pollution viruses. IMPORTANCE Most emerging infectious diseases are due to zoonotic disease agents. Because of their effects on the security of human or animal life, agriculture production, and food safety, zoonotic illnesses and livestock diseases are of worldwide significance. Because dogs are closely related to humans and domestic animals, they serve as one of the important links in the transmission of zoonotic and livestock diseases. Canines can contaminate the environment in which humans live such as water and soil through secretions, potentially altering the human gut microbiota or causing diseases. Our study enriched the viral community in the digestive tract microbiome of dogs and found types of viruses that threaten human health, providing technical support for the prevention and control of early warning of diseases caused by environmental contaminant viruses.

Comparing phylogenetic codivergence between polyomaviruses and their hosts

Seventy-two full genomes corresponding to nine mammalian (67 strains) and two avian (5 strains) polyomavirus species were analyzed using maximum likelihood and Bayesian methods of phylogenetic inference. Our fully resolved and well-supported (bootstrap proportions > 90%; posterior probabilities = 1.0) trees separate the bird polyomaviruses (avian polyomavirus and goose hemorrhagic polyomavirus) from the mammalian polyomaviruses, which supports the idea of spitting the genus into two subgenera. Such a split is also consistent with the different viral life strategies of each group. Simian (simian virus 40, simian agent 12 [Sa12], and lymphotropic polyomavirus) and rodent (hamster polyomavirus, mouse polyomavirus, and murine pneumotropic polyomavirus [MPtV]) polyomaviruses did not form monophyletic groups. Using our best hypothesis of polyomavirus evolutionary relationships and established host phylogenies, we performed a cophylogenetic reconciliation analysis of codivergence. Our analyses generated six optimal cophylogenetic scenarios of coevolution, including 12 codivergence events (P < 0.01), suggesting that Polyomaviridae coevolved with their avian and mammal hosts. As individual lineages, our analyses showed evidence of host switching in four terminal branches leading to MPtV, bovine polyomavirus, Sa12, and BK virus, suggesting a combination of vertical and horizontal transfer in the evolutionary history of the polyomaviruses.

Common and unique features of T antigens encoded by the polyomavirus group

Although 12 different members of the polyomavirus group have now been identified, only SV40 and PyV have been studied extensively. Whereas each member of the group shows a restricted host range, viruses infecting species from birds to humans have been reported. Although little is known concerning the biology of natural infections in the wild, it is apparent that these viruses exhibit various cell-type tropisms. Some viruses, such as LPV (B lymphocytes) or KV (pulmonary endothelium), are tightly restricted to specific cell types, while others, such as PyV, infect a variety of tissues in the animal. Despite these differences, all polyomaviruses share a common strategy of productive infection, expressing T antigens which act both on cellular targets, preparing cellular metabolism for supporting optimal viral replication, and then on targets within the viral genome, to regulate viral DNA replication, transcription, and assembly. Presumably, this common replication strategy restricts the degree to which the sequences of these viruses can diverge. Thus, sequence motifs conserved among these different viruses may indicate key structural elements essential for biochemical function. In this article I have compared the sequences of all polyomavirus-encoded large and small T antigens sequenced to date. This has led to the following conclusions and speculations. (i) Comparison of the domain organization of different large T antigens reveals that these proteins fall into two structural classes. Members of the SV40 class, which include SV40, JCV, BKV, and SA12, possess a carboxyl-terminal domain, which in SV40 has been shown to be dispensable for viral DNA replication but essential for virion assembly. The PyV class lacks the carboxyl-terminal domain and carries additional amino acids within the amino-terminal domain. When total amino acid identity is examined, members of the SV40 class show the highest degree of conservation (65 to 85%), while sequence identity among the remaining viruses varies from 18 to 55%. (ii) The DNA binding domains of most large T antigens are closely related, with amino acid identities ranging from 35 to 86%. Several residues within this domain are invariant among all T antigens. All of these viruses have multiple copies of the consensus T-antigen-binding pentanucleotide (GAGGC) in their ori region, suggesting that all T antigens recognize this sequence. The single exception is the large T antigen encoded by the avian virus BFDV. The putative DNA binding domain of this protein shows little or no sequence relation to that of other T antigens. Furthermore, the GAGGC motif is not found in the ori region of this virus.(ABSTRACT TRUNCATED AT 400 WORDS)

Characterization of a new polyomavirus (Polyomavirus papionis-2) isolated from baboon kidney cell cultures

Viruses with papovavirus morphology were seen in fluids from baboon kidney cell cultures on three separate occasions (isolates A, B, and C). The size of the virions, 47.9 nm, placed the virus in the polyomavirus genus. It grew well in baboon kidney and Vero cells and less well in human embryo lung (HEL) fibroblasts. The virus could not be identified as the previously described baboon polyomavirus, SA 12, or as any of the other known primate polyomaviruses BK, JC or SV 40, the non-primate viruses mouse polyoma, K, rabbit kidney vacuolating virus (RKV) or bovine polyomavirus (FRKV) by immunofluorescence, immune electron microscopy or hemagglutination inhibition (HI) tests. A rabbit antiserum to the new virus (isolate A) reacted only with the three isolates and not with the other primate polyomaviruses studied. Thirteen percent of 118 wild-caught baboons (Papio anubis) had HI antibody to the new polyomavirus and 21 percent were seropositive for SA 12; only two baboons had antibody to both viruses. These results suggest that in baboons there are two antigenically distinct polyomaviruses which circulate independently. The two viruses may also be distinguished by their hemagglutinating properties: SA 12 agglutinated erythrocytes from a wider range of species but only the newly recognized polyomavirus agglutinated baboon erythrocytes. We propose that the two baboon viruses, SA 12 and the new virus, should be named Polyomavirus papionis-1 and Polyomavirus papionis-2 respectively.

Concurrent replication of a papovavirus and a C-type virus in the CCL 33 porcine cell line

A papovavirus, CCL 33 PV, isolated from a porcine cell line, CCL 33 (GT), was characterized. Based on a comparison of four isoenzyme systems, CCL 33 (GT) and CCL 33 (ATCC), obtained directly from the American Type Culture Collection, appeared to be the same. In addition to the previously characterized C-type virus of CCL 33 cultures, CCL 33 (GT) produced CCL 33 PV in high quantity, but CCL 33 (ATCC) produces a papovalike virus, presumably the same as CCL 33 PV, in barely detectable amounts. Serological results showed that CCL 33 PV is apparently identical to a papovavirus (SPV) isolated by Newman and Smith after inoculation of CCL 33 with concentrated porcine trypsin. These studies extend the characterization of this papovavirus, demonstrating that CCL 33 PV is weakly hemagglutinating after neuraminidase treatment, has a high affinity for a component of fetal bovine serum and is highly infectious in appropriate porcine cell systems rather than very defective as reported previously. Moreover, it was concluded from the data that CCL 33 PV is probably indigenous to the CCL 33 porcine cell line.

Transformation of rabbit kidney cells by BKV(MM) human papovavirus

Primary rabbit kidney cells were transformed by BKV(MM), a papovavirus isolated from the urine of a child with the Wiskott-Aldrich syndrome. The transformed cells contained BK T-antigen, but no antigen that reacted with SV40 U-antiserum. The transformed cells failed to produce tumors in nude mice, and BKV (MM) was not rescued from transformed cells by cell fusion or chemical induction methods. The transformed cells supported the growth of rabbit kidney vacuolating virus (RKV), and could be used to quantitate RKV by plaque formation under an agar overlay.

Human papovavirus, BK strain: biological studies including antigenic relationship to simian virus 40

Some of the properties of a new human papovavirus, BK, have been examined. Host range studies of BK virus (BKV) showed human cells to be more sensitive to infection than monkey cells; human fetal brain cells appear to be highly sensitive to BKV, with the production of extensive cytopathology characterized by cytoplasmic vacuolization. The hemagglutinin of BKV is associated with the virion and is resistant to ether or heating at 56 C for 30 min. Fluorescent antibody as well as neutralization tests indicated antigenic similarities between simian virus 40 (SV40) and BKV. Cells undergoing lytic infection with BKV synthesized intranuclear T antigen(s) which reacted with SV40 T antibody demonstrable by immunofluorescence. However, BKV did not appear to induce SV40 transplantation antigens in transplantation-resistance tests. Evidence was obtained that BKV was present in humans prior to the widespread use of polio vaccines, thus ruling out the possibility that BKV is an SV40-related monkey virus, introduced into the human population by accidental contamination of poliovirus vaccines.

Induction of arginase activity with the Shope papilloma virus in tissue culture cells from an argininemic patient

Inoculation of the Shope virus in tissue cultures of human fibroblasts from a patient with a deficiency of the enzyme arginase results in an induction of arginase activity, apparently virus coded.

Change in the structure of Shope papilloma virus-induced arginase associated with mutation of the virus

The change in the state of the virus-induced enzyme associated with a mutation in the virus provides additional evidence that the enzyme is synthesized from virus rather than rabbit genetic information. This change in structure results in differences in stability of polymerization, degree of optical rotary dispersion (ORD) specific rotation, change in elution characteristics from carboxymethyl cellulose, and a reduction in specific activity of the arginase. Liver arginase differs markedly in ORD characteristics from the virus-induced enzyme. In contrast to the virus-induced enzyme, it showed no negative Cotton effect at 233 nm until it was activated with manganese. Manganese had no influence on the ORD spectrum of virus-induced arginase. In addition, liver arginase is denatured by 4 M urea, while the virus-induced enzyme requires 10 M urea for denaturation.

Isolation and characterization of a herpes-like virus from New Zealand albino rabbit kidney cell cultures: a probable reisolation of virus 3 of Rivers

An agent which possesses the physical, chemical, cytopathic, histological, and electron microscopic attributes of a herpes group virus was isolated from an uninoculated batch of primary rabbit kidney cell cultures. Preliminary evidence indicates that antibodies against the agent are found in some sera of other "normal" New Zealand albino rabbits. In cell cultures, the virus grew best and almost exclusively in cells of rabbit origin. On the basis of these facts, the name herpesvirus cuniculi (HC) is suggested for the isolate. A batch of anti-herpesvirus bovis antiserum prepared in rabbits was found to be "contaminated" with unsuspected neutralizing antibodies against HC. Caution is mandatory when using rabbits, rabbit tissues, or rabbit sera for work with any herpes group virus unless precautions are taken to rule out unsuspected infection with or antibodies against HC. This agent may well represent a reisolation of virus III, a rabbit herpes virus, described by Rivers in 1923; the isolation of this virus has not been reported since 1940. It is important to reemphasize the existence of this agent in an animal which is commonly used for laboratory investigation of herpes group viruses.

Human papova (wart) virus

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