Prymnesiovirus

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Prymnesiovirus
Systematics
Classification : Viruses
Area : Varidnaviria
Empire : Bamfordvirae
Phylum : Nucleocytoviricota
Class : Megaviricetes
Order : Algavirales
Family : Phycodnaviridae
Genre : Prymnesiovirus
Type : Chrysochromulina brevifilum virus PW1
(CbV-PW1) 
Taxonomic characteristics
Genome : dsDNA linear
Baltimore : Group 1
Symmetry : icosahedral
Cover : available
Scientific name
Prymnesiovirus
Left
NCBI  Taxonomy: 181086
ViralZone ( ExPASy , SIB): 592

Prymnesiovirus is a genus of viruses from the family Phycodnaviridae with flagellated algae as natural hosts. The genus isofficially registeredby the International Committee on Taxonomy of Viruses (ICTV)as of July 2017, with only one species, the type species Chrysochromulina brevifilum virus PW1 ( CbV-PW1 ). CbV-PW1 infects two species of marine phytoplankton , Haptolina brevifila alias Chrysochromulina brevifilum (Edvardsen et al., 2011), and C. strobilus , which belong to the Prymnesiophyceae ( Haptophyta ). The algae genus Chrysochromulina (or Haptolina ) of the hosts of CbV-PW1 is a particularly important genus, as itcan comprisemore than 50% of the photosynthetic cells of the nano plankton in the ocean.

construction

The virus particles (virions) of the genus Prymnesiovirus are enveloped and have rounded icosahedral geometry with T = 169 symmetry , the diameter is 100-170  nm , in Phaeocystis globosa virus 1 (PgV-01T) it is 106 nm. The genome is unsegmented and linear with a length of about 120 to 485  kb .

Propagation cycle

The virions pass via cell receptor endocytosis ( English cell receptor endocytosis ) in the host cell. Viral replication is nukleozytoplasmatisch and follows the DNA strand-displacement model ( English DNA beach displacement model ). The method of transcription is DNA-based ( English DNA-templated transcription ).

In 1995, Suttle and Chan were the first to isolate viruses that infect prymnesiophytes or haptophytes. In this study, ultra-thin sections of virus particles in Chyrsochromulina brevifilum were dissected and viewed using transmission electron microscopy (TME ). Electron micrographs in the early stages of infection suggest that virus replication takes place in the cytoplasm within a viroplasm (a viroplasm is a localized area in the cytoplasm or around the cell nucleus that serves as a "viral replication factory" or virus factory ). The viroplasm contains components such as virus genes, host proteins and ribosomes , which are necessary for replication. Virosomes are often surrounded by a membrane; in the case of CbV-PW1, this membrane was found to consist of a fibrillar matrix.

The virus leaves the host cell by lysis by means of lytic phospholipids . After breaking the organelles and lysing the host cell membrane, the virions are released from the infected cells. In 1995, Suttle and Chan counted more than 320 virus particles in an ultra-thin section of an infected cell. Estimates for these burst sizes range from a total of 320 to 600 virus particles per cell. The transmission route is passive diffusion.

Systematics

According to ICTV (as of July 2019, Master Species List # 34 2018b v1):

  • Genus prymnesiovirus
  • Species Chrysochromulina brevifilum virus PW1 (CbV-PW1, type species)

The National Center for Biotechnology Information (NCBI) also lists the following previously unclassified putative species of this genus:

  • Species Chrysochromulina brevifilum virus PW3 (CbV-PW3)
  • Species Chrysochromulina parva virus (PgV)
  • Species Prymadium parvum DNA virus BW1
  • Species Phaeocystis globosa virus
  • Species Phaeocystis globosa virus 12T (PgV-12T, T stands for Texel , Netherlands) - see note below
  • Species Phaeocystis globosa virus 14T (PgV-14T) - see note below

Further candidates after the 9th report of the ICTV were:

  • Species Phaeocystis globosa virus 1 (PgV-01T)
  • Species Phaeocystis globosa virus 2 to 11 (PgV-02T to PgV-11T)
  • Species Phaeocystis globosa virus 13 (PgV-13T)
  • Species Phaeocystis globosa virus 15 (PgV-15T)
  • Species Phaeocystis globosa virus 16 (PgV-16T) - see note below
  • Species Phaeocystis globosa virus 17 (PgV-17T)
  • Species Phaeocystis globosa virus 18 (PgV-18T)
  • Species Phaeocystis globosa virus 102 (PgV-102P, P stands for Plymouth , South West England)

According to more recent studies, some of these candidates are more likely to be assigned to the Mimiviridae (proposed subfamily “ Mesomimivirinae ” or sister family “ Mesomimiviridae ”, with the previous group “ OLPG ”). According to Claviere et al (2018), this applies in particular to PgV-16T, which definitely belongs to a different virus group than PgV-01T, according to Abrahão et al (2018), in addition to PgV-16T, also to PgV-12T and PgV-14T. Other candidates are:

  • Species Phaeocystis pouchetii virus (PpV)
  • Species Prymadium kappa virus RF01 and RF02 (PkV-RF01, PkV-RF02)
  • Species Chrysochromulina ericina virus (CeV) alias Haptolina ericina virus (HeV)

Individual evidence

  1. ↑ a b c d e ICTV: ICTV Master Species List 2019.v1 , New MSL including all taxa updates since the 2018b release, March 2020 (MSL # 35)
  2. ↑ a b c d e Viral Zone: Prymnesiovirus . ExPASy. Retrieved July 11, 2019.
  3. ↑ a b ICTV: Virus Taxonomy
  4. ↑ SF Mirza et al : Isolation and characterization of a virus infecting the freshwater algae Chrysochromulina parva , in: Virology Volume 486, December 2015, pp. 105-115, doi: 10.1016 / j.virol.2015.09.005 , see Fig. 4 .
  5. ^ A b c d e Curtis A. Suttle, Amy M. Chan: Viruses infecting the marine Prymnesiophyte Chrysochromulina spp .: Isolation, preliminary characterization and natural abundance . In: Marine Ecology Progress Series . 118, 1995, pp. 275-282. bibcode : 1995MEPS..118..275S . doi : 10.3354 / meps118275 .
  6. ^ Curtis A. Suttle, Amy M. Chan: Prymnesiovirus . In: The Springer Index of Viruses 2002, ISBN 978-3-540-67167-1 , pp. 741-743, doi : 10.1007 / 3-540-31042-8_128 .
  7. ↑ Chrysochromulina Lackey, 1939 :: AlgaeBase .
  8. ↑ a b c d Jean-Michel Claverie, Chantal Abergel: Mimiviridae : An Expanding Family of Highly Diverse Large dsDNA Viruses Infecting a Wide Phylogenetic Range of Aquatic Eukaryotes]. In: Viruses . 2018 Sep; 10 (9), September 18, 2018, p. 506, doi: 10.3390 / v10090506 , PMC 6163669 (free full text), PMID 30231528 , Tab. 2
  9. ^ Andrew MQ King: Virus Taxonomy: Classification and Nomenclature of Viruses: Ninth Report of the International Committee on Taxonomy of Viruses . Elsevier, January 1, 2012, ISBN 9780123846846 .
  10. ↑ NCBI: Prymnesiovirus (Genus)
  11. ↑ a b Andrew MQ King, Michael J. Adams et al. : [1] , 9th Report of the ICTV, 2011/2012, ScienceDirect
  12. ↑ a b c d Jônatas Abrahão, Lorena Silva, Ludmila Santos Silva, Jacques Yaacoub Bou Khalil, Rodrigo Rodrigues, Thalita Arantes, Felipe Assis, Paulo Boratto, Miguel Andrade, Erna Geessien Kroon, Bergmann Ribeiro, Ivan Bergier, Herve Seligmann, Eric Ghigo , Philippe Colson, Anthony Levasseur, Guido Kroemer, Didier Raoult, Bernard La Scola: Tailed giant Tupanvirus possesses the most complete translational apparatus of the known virosphere . In: Nature Communications . 9, No. 1, February 27, 2018. doi : 10.1038 / s41467-018-03168-1 .
  13. ↑ Willie Wilson, Declan C. Schroeder, Jenna Ho, Martin Canty: Phylogenetic analysis of PgV-102P, a new virus from the English Channel that infects Phaeocystis globosa , in: J Mar Biol Ass UK 86, June 2006, p. 485- 490, doi: 10.1017 / S0025315406013385
  14. ↑ NCBI: Phaeocystis pouchetii virus (species)
  15. ↑ a b c Lucie Gallot-Lavallee, Guillaume Blanc, Jean-Michel Claverie: Comparative genomics of Chrysochromulina Ericina Virus (CeV) and other microalgae-infecting large DNA viruses highlight their intricate evolutionary relationship with the established Mimiviridae family , in: J. Virol ., April 26, 2017, doi: 10.1128 / JVI.00230-17
  16. ↑ NCBI: Prymadium kappa virus (species)
  17. ↑ a b Torill Vik Johannessen, Gunnar Bratbak, Aud Larsenb, Hiroyuki Ogatac, Elianne S. Egged, Bente Edvardsen, Wenche Eikremd, Ruth-Anne Sandaaa: Characterization of three novel giant viruses reveals huge diversity among viruses infecting Prymnesiales (Haptophyta) , in : Virology, Volume 476, February 2015, pp. 180-188, doi: 10.1016 / j.virol.2014.12.014 , PMID 25546253
  18. ↑ NCBI: Chrysochromulina ericina virus (species)
  19. ^ JB Larsen, A. Larsen, G. Bratbak, R.-A. Sandaa: Phylogenetic Analysis of Members of the Phycodnaviridae Virus Family, Using Amplified Fragments of the Major Capsid Protein Gene , in: Applied and Environmental Microbiology, 2007/2008, doi: 10.1128 / AEM.02548-07 , PMID 18359826 , Fig. 4