RESUMEN
We suggest a bacteriophage genus, "Viunalikevirus", as a new genus within the family Myoviridae. To date, this genus includes seven sequenced members: Salmonella phages ViI, SFP10 and ΦSH19; Escherichia phages CBA120 and PhaxI; Shigella phage phiSboM-AG3; and Dickeya phage LIMEstone1. Their shared myovirus morphology, with comparable head sizes and tail dimensions, and genome organization are considered distinguishing features. They appear to have conserved regulatory sequences, a horizontally acquired tRNA set and the probable substitution of an alternate base for thymine in the DNA. A close examination of the tail spike region in the DNA revealed four distinct tail spike proteins, an arrangement which might lead to the umbrella-like structures of the tails visible on electron micrographs. These properties set the suggested genus apart from the recently ratified subfamily Tevenvirinae, although a significant evolutionary relationship can be observed.
Asunto(s)
Bacteriófagos/clasificación , Bacteriófagos/genética , Myoviridae/clasificación , Myoviridae/genética , Bacteriófagos/ultraestructura , Colifagos/clasificación , Colifagos/genética , Colifagos/ultraestructura , Genoma Viral , Glicósido Hidrolasas , Myoviridae/ultraestructura , Filogenia , Fagos de Salmonella/clasificación , Fagos de Salmonella/genética , Fagos de Salmonella/ultraestructura , Análisis de Secuencia de ADN , Especificidad de la Especie , Proteínas Virales/química , Proteínas Virales/genética , Proteínas de la Cola de los Virus/química , Proteínas de la Cola de los Virus/genéticaRESUMEN
BACKGROUND: Plasmodium vivax is responsible for approximately 80 million malaria cases in the world. Apical membrane antigen1 (AMA-1) is a type I integral membrane protein present in all Plasmodium species. AMA-1 interferes in critical steps of invasion of human hepatocytes by sporozoites and red blood cells by merozoites and is one of the most immunodominant antigens for eliciting a protective immune response in human. It is considered as a promising antigen for inclusion in a vaccine against P. vivax. Since more knowledge is needed to lighten the scope of such antigen we compared genetic variation in P. vivax AMA-1from an Iranian isolate with those reported from some of the other malarious countries so far. METHODS: P. vivax genomic DNA was extracted from the whole blood of an Iranian patient with patent P. vivax infection. The nucleotide sequence for 446 amino acid (AA) residues (42-488 of PvAMA-1) was amplified by PCR and cloned in pUC19 vector for sequencing. RESULTS: Sequence analysis of the antigen showed a high degree of identity (99%) with strong homology to the PvAMA-1 gene of P. vivax S3 and SKO814 isolates from India and Korea (Asian isolates) respectively, and 96% similarity with P. vivax Sal-1 AMA-1 gene from El Salvador. CONCLUSIONS: We cloned and characterized three domains of PvAMA-1 gene from an Iranian patient. Predicted protein sequence of this gene showed some discrepancies in corresponding protein in comparing with similar genes reported from other malarious countries.