Phocid distemper virus See Phocine distemper virus

Phocid herpesvirus 1 (PhoHV-1) A species in the genus Varicellovirus isolated from harbor seals, Phoca vitulina, during an outbreak of pneumonia and focal hepatitis in a seal orphanage in the Netherlands in which half the seals died. Subsequently, related viruses were isolated from harbor seals in Germany and the USA, and from the European grey seal, Halichoerus grypus. Synonym: harbor seal herpesvirus.

Osterhaus ADME et al (1985) Arch Virol 86, 239

phocid herpesvirus 2 (PhHV-2) A group of herpesviruses were isolated from seals, Phoca vitulina, and a Californian sea lion, Zalophus californicus. These all bear closest sequence relationship to members of the subfamily Gammaherpesvirinae.

Harder TC et al (1996) J Gen Virol 77, 27

Phocine distemper virus (PDV) A species in the genus Morbillivirus. Caused an epizootic in harbor seals, Phoca vitulina, in the Baltic and North seas in 1988. Related to Canine distemper virus, about 70% by nucleotide sequence analysis. Epizootio-logy is poorly understood. Synonym: seal distemper virus.

Barrett T et al (1993) Virology 193, 1010 Kennedy S (1998) J Comp Pathol 119, 201 Visser IKG et al (1993) J Gen Virol 74, 631

phocine morbillivirus

phocine morbillivirus See Phocine distemper virus.

phosphatase An enzyme that catalyzes the hydrolysis and synthesis of phosphoric acid esters and the transfer of phosphate groups from phosphoric acid to other compounds.

phosphodiester bond Link formed between the nucleotides of polynu-cleotide chains by covalent bonding of the phosphoric acid with the 3'-hydroxyl group of one ribose or deoxyribose molecule and the 5'-hydroxyl group of the next ribose or deoxyribose ring. See nucleic acid.

phospholipase An enzyme that catalyzes the hydrolysis of a phospholipid, e.g. lecithinase that acts on lecithin. Used in the study of viral membranes.

phosphonoacetic acid (PAA) An antiviral agent, used as the sodium salt. Inhibits replication of some DNA viruses by blocking DNA synthesis. Superseded by phosphonoformate.

Felsenfeld AD et al (1978) Antimicrobiol Ag Chemother 14, 331

phosphonoformate See trisodium phos-phonoformate (foscarnet). Synonym: fosfonet.

phosphoprotein A protein that has had one or more amino acids phosphorylated by a protein kinase. The amino acids most commonly phosphorylated are serine, threonine and tyrosine.

phosphotungstic acid A negative stain used for electron microscopy of viruses. It consists of dodecatungstophosphoric acid dissolved in water to give a 1-2% solution and adjusted to about pH 7 with NaOH.

photodynamic inactivation Inactivation of viruses by visible light in the presence of certain photoreactive dyes: acridine orange, acriflavine, brilliant cresyl blue, methylene blue, neutral red, proflavine and toluidine blue. The dye is able to pass through the cell membrane and become associated with the DNA. The antiviral effect is seen when light energy absorbed by the dye causes photochemical oxidation of any viral DNA with which it has become associated. Clinical use limited to treatment of superficial herpetic lesions.

Myers MG et al (1975) New Engl J Med 293, 945 Yen GSL and Simon EH (1978) J Gen Virol 41, 273

photoreactivation The repair of UV-inactivated viral DNA by cellular enzymes activated by exposure to longwave light. Such enzymes are found in the cells of bacteria, birds and frogs but not placental mammals.

Pfefferkorn ER and Boyle MK (1972) J Virol 9, 474

photo-Shootur virus See Camelpox virus.

phylogenetic tree A diagrammatic representation of the interrelationships between biological attributes of organisms or genes. For viruses, it is usually based on genome nucleic acid sequences. See parsimony. Synonym: cladogram.

Hillis DM et al (1993) Meth Enzymol 224, 456

phylogeny The evolutionary history of a species or other taxonomic group.

phytohemagglutinin A plant-derived lectin that agglutinates mammalian erythro-cytes, and is a mitogen that stimulates predominantly T lymphocytes. The most commonly used phytohemagglutinin is derived from the red kidney bean, Phaseolus vulgaris.

Phytoreovirus A genus of the family Reoviridae containing species which infect plants and insects.

Pichinde virus (PICV) A species in the genus Arenavirus. One of the New World arenaviruses, belonging to the Tacaribe serogroup. Isolated from the rodents, Oryzomys albigularis and Thomasomys fus-catus, mosquitoes of Ixodes sp and mites of Gigantolaelaps sp in Colombia. Not reported to cause disease in humans.

picobirnavirus A virus first identified in rat feces and later in humans and other animals. Contains a genome consisting of two segments of double-stranded RNA, 2.6 and 1.5kb in length. A probable cause of diarrhea in humans.

Picodna virus A name proposed but not adopted for the family Parvoviridae.

Picola virus (PIAV) A serotype of Wongorr virus in the genus Orbivirus. Isolated from Culex annulirostris mosquitoes in Victoria, Australia. Not known to cause disease in humans.

Picornaviridae (Latin pico = small) A family of naked, ether-resistant viruses with icosahedral capsids 22-30nm in diameter. The capsid is composed of several different polypeptides whose apparent size can vary between closely related strains, but whose aggregate mol. wt. lies between 80000 and 120000. Typically there are equal amounts of four major capsid polypeptides, three (1B, 1C and 1D) of mol. wt. 20000-40000 and one (1A) of mol. wt. 5000-10000. Proteins 1A, 1B, 1C and 1D are commonly known as VP4, VP2, VP3 and VP1, respectively. Proteins 1B, 1C and 1D each possess a core structure comprising an eight-stranded beta sandwich (BETA-barrel). One molecule of each makes up the capsid structural unit. The capsid is composed of 60 structural units, with T = 1, pseudo T = 3 icosahedral symmetry. The genome RNA of 7-8.5kb in length is infectious. It is the message for protein translation and carries a poly A tract at the 3' end added transcriptionally. A small protein, VPg, is linked covalently to the 5' terminus. Virus multiplication occurs in the cytoplasm and functional proteins are mainly produced by processing and post-translational cleavage of a nascent precursor polyprotein. There are six genera: Aphthovirus, Enterovirus, Cardiovirus, Hepatovirus, Parechovirus and Rhinovirus, distinguished by sensitivity to acid, buoyant density of the virion and clinical features of infection in susceptible hosts.

Hyypia T et al (1997) J Gen Virol 78, 1 Minor P (1998) In Virology, vol. 1 of Topley & Wilson's Microbiology and Microbial Infections, Ninth edition, edited by BWJ Mahy and L Collier. London: Arnold, p. 485

picornavirus epidemic conjunctivitis virus A name proposed for acute hemorrhagic conjunctivitis virus since the severity and frequency of the subcon-junctival hemorrhages is very variable. This term would also include conjunctivitis due to coxsackie virus A24. Not adopted.

Lim KH and Yin-Murphy M (1977) Singapore Med J18, 41

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