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At least 37 records · Page 2Linked to original sources
PubMed1995

Nucleotide sequence of feline immunodeficiency virus: classification of Japanese isolates into two subtypes which are distinct from non-Japanese subtypes.

Seven isolates of feline immunodeficiency virus (FIV), Shizuoka, Yokohama, Sendai-1, Sendai-2, Fukuoka, Aomori-1, and Aomori-2, were isolated from FIV-seropositive domestic cats in Japan, and their proviral DNAs were amplified by PCR. The nucleotide sequences of their env and gag genes were determined and compared with those of previously described isolates: U.S. and European isolates and one Japanese isolate, TM2. Phylogenetic analyses of complete env gene sequences demonstrate that worldwide isolates are classified into three subtypes: Japanese TM2, Japanese Shizuoka, and non-Japanese subtypes (U.S. and European isolates), with 20% amino acid distances from each other. This pattern indicates that an evolutionary radiation of these three subtypes of FIV occurred at approximately the same time. The sequence data of gag genes also confirmed these results. Furthermore, the Sendai-1 isolate was identified as an imported FIV isolate.

Amino Acid Sequence↗
PubMed1991

Genetic diversity of human parvovirus B19 determined using a set of restriction endonucleases recognizing four or five base pairs and partial nucleotide sequencing: use of sequence variability in virus classification.

Analysis of the restriction site polymorphism (RSP) of human parvovirus B19 using 12 restriction endonucleases (REs) recognizing four or five bp sequences (4- or 5-bp REs) revealed a significant difference between strains previously classified as being of the same genome type, and a relationship between two strains of different genome types, thereby indicating a global spread of B19 virus strains. These findings demonstrate the advantage of this set of 4- and 5-bp REs for the calculation of the degree of genetic diversity and clearly it is necessary to amend the taxonomy of B19 virus strains using these REs. We examined the nucleotide (nt) sequence between nt 3141 and 3411, at the N terminus of the VP2 protein coding region, in 12 B19 virus strains. The pattern of distribution of nucleotide differences between the strains confirmed the classification by RSP analysis. Between nt 3293 and nt 3364, a region in which an antigenic epitope may be encoded, there was no evidence of a nucleotide change causing an amino acid change. Thus, the amino acid sequence in this potential epitope is probably conserved.

Cloning, Molecular↗
PubMed1972

Wild-type gross leukemia virus: classification of soluble antigens (GSA).

By inhibiting techniques using indirect immunofluorescence tests and indirect immunoelectron microscopy, the G(Gross) soluble antigens (GSA) in the body fluids of AKR and C58 mice, which have a high incidence of spontaneous leukemia, were classified according to the known specificity of G antigens in the murine Gross leukemia system. GSA existing in the plasma of nonleukemic and leukemic AKR mice and in the ascitic fluid of transplanted AKR spontaneous leukemia K36 showed the several specificities corresponding to G cell surface antigens, GCSAa, b, and c, and type-specific and group-specific viral envelope antigens, tsVEA and gsVEA, respectively. However, the plasma of nonleukemic C58 mice lacks GSAc, which can be recognized by the G-typing mouse serum. GSA corresponding to G(IX) antigen was not detected in the body fluids.

AKR murine leukemia virus↗
PubMedDate not supplied

[Classification of viruses by computer].

The study used the information mass containing information on 83 viruses characterized by 41 markers. The suitability of one of the variants of cluster analysis for virus classification was demonstrated. It was established that certain stages of automatic allotment of viruses into groups by the degree of similarity of their properties end the formation of groups which consist of viruses sufficiently close to each other by their properties and are sufficiently isolated. Comparison of these groups with the classification proposed by the ICVT established their correspondence to individual families. Analysis of the obtained classification system permits sufficiently grounded conclusions to be drawn with regard to the classification position of certain viruses, the classification of which has not yet been completed by the ICVT.

Bacteriophages↗
PubMed1986

Nature and classification of viruses affecting small animals.

The classification of animal viruses is predicated upon the various parameters discussed herein and the molecular biology of viruses. Although many of the parameters used for classification purposes have little obvious relation to the disease the veterinarian observes, it is necessary to utilize this information collectively to understand viral classification and its relationship to disease pathogenesis, treatment, diagnosis, and prevention because all these are predicted on the classification of animal viruses (Table 2).

Animals↗
PubMedDate not supplied

[Numerical classification of viruses within families].

The possibility of using cluster analysis for allocation of viruses into groups having a taxonomic rank below the family was studied. As a result, a modified variant of cluster analysis is proposed which may be used for investigation of similarities and differences among viruses within individual families and formation of groups corresponding to those of a lower taxonomic rank than the family. The use of this modified variant of cluster analysis allowed the authors to distinguish groups in the majority of the families studied corresponding to ICTV genera. The data have been obtained suggesting the necessity of changing the taxonomic rank of some virus groups. The above studies have shown the possibility of developing numerical classification of viruses at the subfamily and genus levels, in other words, a single hierarchical numerical classification of viruses.

Adenoviridae↗
PubMed1986

Evidence that the amino acid composition of the particle proteins of plant viruses is characteristic of the virus group. I. Multidimensional classification of plant viruses.

The amino acid (AA) contents of the coat proteins of 134 plant viruses and strains were classified by principal components analysis. The virus groupings that were obtained correlated well with the classification of Matthews. The relationships of each virus were dependent on the number of AA residues (axis 1) and on the percentage composition of each AA in the proteins (axes 2-4). The classification indicated which data were anomalous and needed confirmation. There seemed to be more anomalies in estimates of protein size than of protein composition.

Amino Acids↗
PubMed1992

What is a virus?

The earlier reluctance of some plant virologists to use the term "virus species" has been overcome and the species has now been accepted as the basic unit in virus classification. A virus species is a polythetic class of viruses that constitutes a replicating lineage and occupies a particular ecological niche. Because of the polythetic nature of virus species, there is no single property, such as a particular level of genome homology, that could be used as the sole criterion for delineating individual virus species.

Plant Viruses↗
PubMed1967

Preliminary classification of viruses based on quantitative comparisons of viral nucleic acids.

It is proposed that classifications used in science are of two main types; those which are designed to solve practical problems and which are based on conventions, and those which are designed to solve theoretical problems, based on theories, and in which the classes are tested by experiment. An attempt has been made to construct a preliminary classification of viruses which is of the second type. It is based on the theories of molecular biology, with the use of computer-based comparisons of the molecular weights and base ratios of viral nucleic acids to assign the viruses to clusters which show a high degree of correlation with groupings based on nucleic acid hybridization, serological cross-reactions, and phenotypic properties.

Classification↗