4 research outputs found
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Survey of Cyanophages: A Study of the Bacteriophages associated with Pacific Northwest Cyanobacterial blooms
Cyanobacterial blooms are a growing concern in the Pacific Northwest because of their
threat to watershed health and drinking water supplies. Bacteriophages are pathogens of
bacteria and may contribute to the growth and decline of seasonal blooms. Bacteriophage
S-CRM01, a lytic T4-type myophage, has been isolated from a freshwater strain of
Synechococcus (Dreher et al., 2011). This phage was isolated from a cyanobacterial
bloom of primarily toxic Microcystis aeruginosa, but an endemic Synechococcus lineage,
that was a minor constituent of the bloom, is the actual host for this phage. This survey
was conducted to assess the distribution of phage S-CRM01 in Oregon and Northern
California in bodies of water with cyanobacterial blooms. On the basis of PCR
identification of plaques on LC16 cyanobacteria plates, S-CRM01 was present across a
length of about 250 km along the Klamath River valley, from the Williamson River Delta
at the northern end of Upper Klamath Lake as far downstream as Seiad Valley in 2009.
Although this phage has not been shown to infect toxic cyanobacteria, it is still valuable
in the freshwater phage community where few genomes have been sequenced
Recommended from our members
Survey of Cyanophages: A Study of the Bacteriophages associated with Pacific
Cyanobacterial blooms are a growing concern in the Pacific Northwest because of their
threat to watershed health and drinking water supplies. Bacteriophages are pathogens of
bacteria and may contribute to the growth and decline of seasonal blooms. Bacteriophage
S-CRM01, a lytic T4-type myophage, has been isolated from a freshwater strain of
Synechococcus (Dreher et al., 2011). This phage was isolated from a cyanobacterial
bloom of primarily toxic Microcystis aeruginosa, but an endemic Synechococcus lineage,
that was a minor constituent of the bloom, is the actual host for this phage. This survey
was conducted to assess the distribution of phage S-CRM01 in Oregon and Northern
California in bodies of water with cyanobacterial blooms. On the basis of PCR
identification of plaques on LC16 cyanobacteria plates, S-CRM01 was present across a
length of about 250 km along the Klamath River valley, from the Williamson River Delta
at the northern end of Upper Klamath Lake as far downstream as Seiad Valley in 2009.
Although this phage has not been shown to infect toxic cyanobacteria, it is still valuable
in the freshwater phage community where few genomes have been sequenced
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A freshwater cyanophage whose genome indicates close relationships to photosynthetic marine cyanomyophages
Bacteriophage S-CRM01 has been isolated from a freshwater strain of Synechococcus and shown to
be present in the upper Klamath River valley in northern California and Oregon. The genome of this
lytic T4-like phage has a 178,563 bp circular genetic map with 297 predicted protein-coding genes
and 33 tRNA genes that represent all 20 amino acid specificities. Analyses based on gene sequence
and gene content indicate a close phylogenetic relationship to the “photosynthetic” marine
cyanomyophages infecting Synechococcus and Prochlorococcus. Such relatedness suggests that
freshwater and marine phages can draw on a common gene pool. The genome can be considered as
being comprised of three regions. Region 1 is populated predominantly with structural genes,
recognized as such by homology to other T4-like phages and by identification in a proteomic
analysis of purified virions. Region 2 contains most of the genes with roles in replication,
recombination, nucleotide metabolism and regulation of gene expression, as well as 5 of the 6
signature genes of the photosynthetic cyanomyophages (hli03, hsp20, mazG, phoH and psbA; cobS
is present in Region 3). Much of Regions 1 and 2 are syntenous with marine cyanomyophage
genomes, except that a segment encompassing Region 2 is inverted. Region 3 contains a high
proportion (85%) of genes that are unique to S-CRM01, as well as most of the tRNA genes. Regions
1 and 2 contain many predicted late promoters, with a combination of CTAAATA and ATAAATA
core sequences. Two predicted genes that are unusual in phage genomes are homologs of cellular
spoT and nusG.Keywords: Myoviridae, Phage tRNA, T4-like phage, Cyanomyophage, Freshwater phage, spoT, Klamath River, nus