Part A | 4.5
38 Part A Marine Flora and Fauna
Table 4.1 Viruses infecting marine organisms
Virus family
Nucleic acid Morphology
Size (nm)
Host
Baculoviridae
dsDNA
Enveloped, rods
200450 100400 Crustacea
Herpesviridae
dsDNA
Enveloped icosahedral
150200
Mollusks, fish, mammals
Iridoviridae
dsDNA
icosahedral
190200
Mollusks, fish
Lipothrixviridae
dsDNA
Enveloped, rod-shaped
40 400
Archaea
Nimaviridae
dsDNA
Enveloped, rod-shaped with tail-like
appendage
120 275
Crustacea
Papovaviridae
dsDNA
Round, icosahedral
4050
Mollusks
Phycodnaviridae
dsDNA
Icosahedral
130200
Algae
Corticoviridae
dsDNA
Icosahedral with spikes
6075
Bacteria
Tectiviridae
dsDNA
Icosahedral with spikes
6075
Bacteria
Myoviridae
dsDNA
icosahedral
80200
Bacteria
Podoviridae
dsDNA
Icosahedral with noncontractile tail
60
Bacteria
Siphoviridae
dsDNA
Icosahedral with noncontractile tail
60
Bacteria
Microviridae
ssDNA
Icosahedral with spikes
2527
Bacteria
Parvoviridae
ssDNA
Round, icosahedral
20
Crustacea
Birnaviridae
dsRNA
Round, icosahedral
60
Mollusks, fish
Reoviridae
dsRNA
Icosahedral, some with spikes
5080
Crustacea (?), mollusks, fish
Cystoviridae
dsRNA
Icosahedral with lipid coat
6075
Bacteria
Bunyaviridae
ssRNA
Round, enveloped
80120
Crustacea (?)
Caliciviridae
ssRNA
Round, icosahedral
3540
Fish, mammals
Coronaviridae
ssRNA
Rod-shaped with projections
200 42
Crustacea
Dicistroviridae
ssRNA
Round, icosahedral
30
Crustacea
Leviviridae
ssRNA
Round, icosahedral
26
Bacteria
Marnaviridae
ssRNA
Round, icosahedral
25
Algae
Nodaviridae
ssRNA
Round, icosahedral
30
Fish
Orthomyxoviridae ssRNA
Round, with spikes
80120
Fish
Paramyxoviridae
ssRNA
Enveloped, filamentous
60300 1000
Mammals
Picornaviridae
ssRNA
Round, icosahedral
27 30
Algae, crustacea (?),
thraustochytrids
Rhabdoviridae
ssRNA
Bullet-shaped with projections
45100 100430
Fish
4.5.2 Cyanophages
Cyanobacteria are photosynthetic prokaryotes; they are
one of the largest and most important groups of bacteria
on earth. Cyanobacteria play an important role as primary producers in the ocean world. Examples are the
cyanobacterial genera Synechococcus and Prochlorococcus, which together account for about 25% of global
photosynthesis [4.19]. However, some groups of viruses
infect cyanobacteria and cause mortality, that is, those
groups of viruses called cyanophages. At the beginning, the causes of cyanobacteria mortality was poorly
understood; it was assumed that it was due to protozoan infection rather than viral infection. However,
the recent research data suggests that up to 7% of
the heterotrophic bacteria and 5% of the cyanobacteria were associated with phages, and approximately
70% of prokaryotes might be infected by viruses [4.20].
In the 1990s, the first viral infection of marine unicellular cyanobacteria was reported and subsequently
the cyanophages were isolated and characterized [4.20,
21].
Horizontal Gene Transfer
The interaction of phages and cyanobacteria may possible for new pathways of carbon and nitrogen cycling
in marine food webs through gene transfer between
marine organisms [4.20]. Metagenomic analysis of viral fractions reveals that cyanophages are widely distributed in the marine environment and interaction
between cyanophages and cyanobacteria have been observed in the ocean [4.22]. Especially, most of the
38 Part A Marine Flora and Fauna
Table 4.1 Viruses infecting marine organisms
Virus family
Nucleic acid Morphology
Size (nm)
Host
Baculoviridae
dsDNA
Enveloped, rods
200450 100400 Crustacea
Herpesviridae
dsDNA
Enveloped icosahedral
150200
Mollusks, fish, mammals
Iridoviridae
dsDNA
icosahedral
190200
Mollusks, fish
Lipothrixviridae
dsDNA
Enveloped, rod-shaped
40 400
Archaea
Nimaviridae
dsDNA
Enveloped, rod-shaped with tail-like
appendage
120 275
Crustacea
Papovaviridae
dsDNA
Round, icosahedral
4050
Mollusks
Phycodnaviridae
dsDNA
Icosahedral
130200
Algae
Corticoviridae
dsDNA
Icosahedral with spikes
6075
Bacteria
Tectiviridae
dsDNA
Icosahedral with spikes
6075
Bacteria
Myoviridae
dsDNA
icosahedral
80200
Bacteria
Podoviridae
dsDNA
Icosahedral with noncontractile tail
60
Bacteria
Siphoviridae
dsDNA
Icosahedral with noncontractile tail
60
Bacteria
Microviridae
ssDNA
Icosahedral with spikes
2527
Bacteria
Parvoviridae
ssDNA
Round, icosahedral
20
Crustacea
Birnaviridae
dsRNA
Round, icosahedral
60
Mollusks, fish
Reoviridae
dsRNA
Icosahedral, some with spikes
5080
Crustacea (?), mollusks, fish
Cystoviridae
dsRNA
Icosahedral with lipid coat
6075
Bacteria
Bunyaviridae
ssRNA
Round, enveloped
80120
Crustacea (?)
Caliciviridae
ssRNA
Round, icosahedral
3540
Fish, mammals
Coronaviridae
ssRNA
Rod-shaped with projections
200 42
Crustacea
Dicistroviridae
ssRNA
Round, icosahedral
30
Crustacea
Leviviridae
ssRNA
Round, icosahedral
26
Bacteria
Marnaviridae
ssRNA
Round, icosahedral
25
Algae
Nodaviridae
ssRNA
Round, icosahedral
30
Fish
Orthomyxoviridae ssRNA
Round, with spikes
80120
Fish
Paramyxoviridae
ssRNA
Enveloped, filamentous
60300 1000
Mammals
Picornaviridae
ssRNA
Round, icosahedral
27 30
Algae, crustacea (?),
thraustochytrids
Rhabdoviridae
ssRNA
Bullet-shaped with projections
45100 100430
Fish
4.5.2 Cyanophages
Cyanobacteria are photosynthetic prokaryotes; they are
one of the largest and most important groups of bacteria
on earth. Cyanobacteria play an important role as primary producers in the ocean world. Examples are the
cyanobacterial genera Synechococcus and Prochlorococcus, which together account for about 25% of global
photosynthesis [4.19]. However, some groups of viruses
infect cyanobacteria and cause mortality, that is, those
groups of viruses called cyanophages. At the beginning, the causes of cyanobacteria mortality was poorly
understood; it was assumed that it was due to protozoan infection rather than viral infection. However,
the recent research data suggests that up to 7% of
the heterotrophic bacteria and 5% of the cyanobacteria were associated with phages, and approximately
70% of prokaryotes might be infected by viruses [4.20].
In the 1990s, the first viral infection of marine unicellular cyanobacteria was reported and subsequently
the cyanophages were isolated and characterized [4.20,
21].
Horizontal Gene Transfer
The interaction of phages and cyanobacteria may possible for new pathways of carbon and nitrogen cycling
in marine food webs through gene transfer between
marine organisms [4.20]. Metagenomic analysis of viral fractions reveals that cyanophages are widely distributed in the marine environment and interaction
between cyanophages and cyanobacteria have been observed in the ocean [4.22]. Especially, most of the