beet yellows virus belong to the genus closterovirus in the closteroviridae family which is one the most important viruses of sugar beet worldwide. in order to identify and characterize some molecular aspects of the byv, 48 symptomatic leaf samples of sugar beet were collected from sugar beet field in khorasan razavi province of iran. leaves showing general yellowing, vein clearing and thicknes...

the plasmid palca1sifn containing cdna that encodes the human interferon a-2b was obtained from the atcc(no. 531667). in this system the expression of the gene is under the control of an alca promoter. alca p is a specific promoter for expression of different genes in aspergillusfilamentous. in this plasmid the coding region of ifn?-2b is preceded by the coding region of a synthetic signal pept...

equine influenza is an acute, infectious and highly contagious respiratory disease with worldwide distribution and high morbidity and low mortality. the disease caused by h7n7 and h3n8 subtypes of genus (type) a of influenza virus. the most significant clinical signs of this disease are fever, coughing and nasal discharge. in this study, the presence of antibody against two subtypes of equine i...

Protein synthesis is believed to be initiated with the amino acid methionine because the AUG translation initiation codon of mRNAs is recognized by the anticodon of initiator methionine transfer RNA. A group of positive-stranded RNA viruses of insects, however, lacks an AUG translation initiation codon for their capsid protein gene, which is located at the downstream part of the genome. The cap...

Passage of foot-and-mouth disease virus (FMDV) in cell culture in the presence of the mutagenic base analog 5-fluorouracil or 5-azacytidine resulted in decreases of infectivity and occasional extinction of the virus. Low viral loads and low viral fitness enhanced the frequency of extinction events; this finding was shown with a number of closely related FMDV clones and populations differing by ...

Simian virus 40 (SV40) was isolated from the brains of three rhesus monkeys and the kidneys of two other rhesus monkeys with simian immunodeficiency virus-induced immunodeficiency. A striking feature of these five cases was the tissue specificity of the SV40 replication. SV40 was also isolated from the kidney of a Taiwanese rock macaque with immunodeficiency probably caused by type D retrovirus...