Infection of Synechococcus cedrorum by the cyanophage AS-1M

Sherman, Louis A.; Pauw, Peter G.

doi:10.1016/0042-6822(76)90090-8

Cited by 33 publications

(22 citation statements)

References 16 publications

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“…Even after 18 h, the cells retained their characteristic green color and showed no visible signs of lysis. In contrast, the culture grown in light increased in density for several hours, then lysed between 6.5 and 9.5 h. The timing of the lysis was consistent with previous reports of AS-1 infection (14,15,16). This result indicates that cells unable to photosynthesize will not support normal lysis by AS-1.…”

Section: Resultssupporting

confidence: 81%

“…These results indicate that should AS-1 infection proceed for a critical period of time in light, the remainder of the infection process can take place while light is limited. The amount of light required for successful AS-1 infection can be related to the progression of events during AS-1 infection (15,16). AS-1 actively degrades the host DNA within 1 h after infection and will inhibit host protein synthesis 3 to 4 h after infection (16).…”

Section: Resultsmentioning

confidence: 99%

“…In addition, phylogenetic analysis has revealed that viruses in aquatic ecosystems are genetically diverse, suggesting that they are under significant selection pressure, perhaps in response to host defense systems and/or variations in the environment (22). Understanding how environmental factors and/or host genetics affect the success of viral infection is therefore relevant to the understanding of aquatic ecosystems.A previously characterized contractile DNA phage of Synechococcus elongatus named AS-1 is a member of the family Myoviridae, which includes the well-characterized T-even phages (11,(14)(15)(16) (Fig. 1A).…”

mentioning

confidence: 99%

“…A previously characterized contractile DNA phage of Synechococcus elongatus named AS-1 is a member of the family Myoviridae, which includes the well-characterized T-even phages (11,(14)(15)(16) (Fig. 1A).…”

mentioning

confidence: 99%

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Diel Infection of a Cyanobacterium by a Contractile Bacteriophage

Kao¹,

Green²,

Stein

et al. 2005

Appl Environ Microbiol

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Light was found to strongly influence the infection of a freshwater cyanobacterium (Synechococcus elongatus PCC 7942) by a contractile DNA phage named AS-1. Phage progeny production was correlated with the amount of light in the laboratory and occurred in a diel pattern under natural light. At least one effect of light on AS-1 infection is at the level of adsorption.Viruses are present in marine and freshwater systems at more than 10 7 particles per milliliter (4,18). This large number argues strongly for an important role in global biological and geochemical processes, including the recycling of nutrient stores due to virus-induced lysis (4,6,13,20). In addition, phylogenetic analysis has revealed that viruses in aquatic ecosystems are genetically diverse, suggesting that they are under significant selection pressure, perhaps in response to host defense systems and/or variations in the environment (22). Understanding how environmental factors and/or host genetics affect the success of viral infection is therefore relevant to the understanding of aquatic ecosystems.A previously characterized contractile DNA phage of Synechococcus elongatus named AS-1 is a member of the family Myoviridae, which includes the well-characterized T-even phages (11,(14)(15)(16) (Fig. 1A). AS-1 infects the well-characterized freshwater obligate phototroph Synechococcus elongatus PCC 7942 (14). A key feature of S. elongatus biology is that its gene expression is regulated by an intrinsic ϳ24-h circadian clock (5,7,8). The products of three key genes, kaiA, kaiB, and kaiC, are required for maintaining the normal gene expression rhythm (7,8). Deletion of any of these three genes will result in a loss of rhythmicity but will not significantly affect growth rates (5). We were initially interested in examining whether mutations in circadian rhythm regulators of S. elongatus would affect AS-1 infection. We found that deletions in the genes that regulate S. elongatus circadian rhythm had only minor effects on AS-1 progeny production, whereas light had a profound influence on the AS-1 infection process. MATERIALS AND METHODSS. elongatus strain AMC541 is the parental strain for the circadian mutants. Strains AMC702, AMC703, and AMC704 have deletions in the kaiA, kaiB, and kaiC genes, respectively. Additional genetic information concerning the strains used can be found in the report of Ditty et al. (5). Cultures were usually grown under constant illumination at 45 mol photons m Ϫ2 s Ϫ1 in a modified BG-11 medium (2). Light intensity was measured with a LiCor luminometer. The original preparation of AS-1 was obtained from the American Type Culture Collection. A stock of at least 10 9 phage per ml was prepared by infecting S. elongatus grown in the presence of light for more than 18 h, followed by two clarifications of the supernatant of the culture lysate by centrifugation. The clarified lysate was stored at 4°C with a drop of chloroform. As previously determined by Safferman et al. (14), the lysate was stable for a minimum of several weeks at 4°C...

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Section: Resultssupporting

confidence: 81%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Diel Infection of a Cyanobacterium by a Contractile Bacteriophage

Kao¹,

Green²,

Stein

et al. 2005

Appl Environ Microbiol

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“…The recent discovery that many lytic cyanophages carry host-like photosynthesis genes indicates that the lytic cycle of their associated cyanophages is also light dependent (Lindell et al, 2005;Sullivan et al, 2006). Additionally, it has been verified for cyanophages S-PM2, AS-1 and AS-1M that phage adsorption is light dependent (Sherman, 1976;Jia and Mann, 2005;Kao et al, 2005). It has been hypothesized that a wave of phage adsorption following dawn could lead to a release of progeny phage later in the day (Clokie and Mann, 2006).…”

Section: Discussionmentioning

confidence: 99%

Comparison of lysogeny (prophage induction) in heterotrophic bacterial and Synechococcus populations in the Gulf of Mexico and Mississippi river plume

et al. 2007

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Lysogeny has been documented as a fundamental process occurring in natural marine communities of heterotrophic and autotrophic bacteria. Prophage induction has been observed to be prevalent during conditions of low host abundance, but factors controlling the process are poorly understood. A research cruise was undertaken to the Gulf of Mexico during July 2005 to explore environmental factors associated with lysogeny. Ambient physical and microbial parameters were measured and prophage induction experiments were performed in contrasting oligotrophic Gulf and eutrophic Mississippi plume areas. Three of 11 prophage induction experiments in heterotrophic bacteria (27%) demonstrated significant induction in response to Mitomycin C. In contrast, there was significant Synechococcus cyanophage induction in seven of nine experiments (77.8%). A strong negative correlation was observed between lysogeny and log-transformed activity measurements for both heterotrophic and autotrophic populations (r ¼ À0.876, P ¼ 0.002 and r ¼ À0.815, P ¼ 0.025, respectively), indicating that bacterioplankton with low host growth favor lysogeny. Multivariate statistical analyses indicated that ambient level of viral abundance and productivity were inversely related to heterotrophic prophage induction and both factors combined were most predictive of lysogeny (q ¼ 0.899, P ¼ 0.001). For Synechococcus, low ambient cyanophage abundance was most predictive of lysogeny (q ¼ 0.862, P ¼ 0.005). Abundance and productivity of heterotrophic bacteria was strongly inversely correlated with salinity, while Synechococcus was not. This indicated that heterotrophic bacterial populations were well adapted to the river plume environments, thus providing a possible explanation for differences in prevalence of lysogeny observed between the two populations.

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Cyanophages and Viruses of Eukaryotic Algae

Sherman

BrownJr.

1978

Newly Characterized Protist and Invertebrate Viruses

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Infection of Synechococcus cedrorum by the cyanophage AS-1M

Cited by 33 publications

References 16 publications

Diel Infection of a Cyanobacterium by a Contractile Bacteriophage

Diel Infection of a Cyanobacterium by a Contractile Bacteriophage

Comparison of lysogeny (prophage induction) in heterotrophic bacterial and Synechococcus populations in the Gulf of Mexico and Mississippi river plume

Cyanophages and Viruses of Eukaryotic Algae

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