Lysogeny in marine Synechococcus

McDaniel, Lauren D.; Houchin, Lee; Williamson, Shannon J.; Paul, John H.

doi:10.1038/415496a

Cited by 128 publications

(103 citation statements)

References 9 publications

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“…However, Synechococcus in Tampa Bay demonstrate greater frequency of lysogenic conversion in summer months when abundances are greater (McDaniel et al, 2002). Thus, when C. watsonii abundance is elevated, transposase activity may be enhanced to defend against phage attack.…”

Section: Resultsmentioning

confidence: 99%

In situ transcriptomic analysis of the globally important keystone N2-fixing taxon Crocosphaera watsonii

et al. 2009

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The diazotrophic cyanobacterium Crocosphaera watsonii supplies fixed nitrogen (N) to N-depleted surface waters of the tropical oceans, but the factors that determine its distribution and contribution to global N 2 fixation are not well constrained for natural populations. Despite the heterogeneity of the marine environment, the genome of C. watsonii is highly conserved in nucleotide sequence in contrast to sympatric planktonic cyanobacteria. We applied a whole assemblage shotgun transcript sequencing approach to samples collected from a bloom of C. watsonii observed in the South Pacific to understand the genomic mechanisms that may lead to high population densities. We obtained 999 C. watsonii transcript reads from two metatranscriptomes prepared from mixed assemblage RNA collected in the day and at night. The C. watsonii population had unexpectedly high transcription of hypothetical protein genes (31% of protein-encoding genes) and transposases (12%). Furthermore, genes were expressed that are necessary for living in the oligotrophic ocean, including the nitrogenase cluster and the iron-stress-induced protein A (isiA) that functions to protect photosystem I from high-light-induced damage. C. watsonii transcripts retrieved from metatranscriptomes at other locations in the southwest Pacific Ocean, station ALOHA and the equatorial Atlantic Ocean were similar in composition to those recovered in the enriched population. Quantitative PCR and quantitative reverse transcriptase PCR were used to confirm the high expression of these genes within the bloom, but transcription patterns varied at shallower and deeper horizons. These data represent the first transcript study of a rare individual microorganism in situ and provide insight into the mechanisms of genome diversification and the ecophysiology of natural populations of keystone organisms that are important in global nitrogen cycling.

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Section: Resultsmentioning

confidence: 99%

In situ transcriptomic analysis of the globally important keystone N2-fixing taxon Crocosphaera watsonii

et al. 2009

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“…However, the FC data presented here are perhaps the strongest evidence thus far that the VLPs present in corals and their relatives, and in the zooxanthellae associated with them, are viruses. The infection of symbiotic algae by viruses would certainly not be surprising, as numerous free-living marine primary producers, including microalgae (Bratbak et al 1996, Lawrence et al 2001, Schroeder et al 2002, Brussaard 2004a), a wide range of cyanobacteria (Proctor & Fuhrman 1990, Wilson et al 1993, Fuller et al 1998, Suttle 2000, Hewson et al 2001, McDaniel et al 2002 and macroalgae (Kapp 1998, Maier & Muller 1998 are susceptible to viral infections. However, we cannot yet state unequivocally that viruses actively propagate within corals or their symbionts; it will be difficult to state this unless a good in vitro system can be established and perhaps used to develop diagnostic markers for detecting virus infection in natural coral reef systems.…”

Section: Discussionmentioning

confidence: 99%

Viruses: agents of coral disease?

Davy

Burchett²,

Dale³

et al. 2006

Dis. Aquat. Org.

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The potential role of viruses in coral disease has only recently begun to receive attention. Here we describe our attempts to determine whether viruses are present in thermally stressed corals Pavona danai, Acropora formosa and Stylophora pistillata and zoanthids Zoanthus sp., and their zooxanthellae. Heat-shocked P. danai, A. formosa and Zoanthus sp. all produced numerous virus-like particles (VLPs) that were evident in the animal tissue, zooxanthellae and the surrounding seawater; VLPs were also seen around heat-shocked freshly isolated zooxanthellae (FIZ) from P. danai and S. pistillata. The most commonly seen VLPs were tail-less, hexagonal and about 40 to 50 nm in diameter, though a diverse range of other VLP morphotypes (e.g. rounded, rod-shaped, droplet-shaped, filamentous) were also present around corals. When VLPs around heat-shocked FIZ from S. pistillata were added to non-stressed FIZ from this coral, they resulted in cell lysis, suggesting that an infectious agent was present; however, analysis with transmission electron microscopy provided no clear evidence of viral infection. The release of diverse VLPs was again apparent when flow cytometry was used to enumerate release by heat-stressed A. formosa nubbins. Our data support the infection of reef corals by viruses, though we cannot yet determine the precise origin (i.e. coral, zooxanthellae and/or surface microbes) of the VLPs seen. Furthermore, genome sequence data are required to establish the presence of viruses unequivocally. KEY WORDS: Viruses · Corals · Zooxanthellae· Coral disease · Coral health · StressResale or republication not permitted without written consent of the publisher

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“…Estimates of the bacterial lysogenic fraction-To estimate the lysogenic fraction among natural populations of marine bacteria, we used one of the most effective and widely used inducing agents, mitomycin C (Weinbauer and Suttle 1996;McDaniel et al 2002;Ortmann et al 2002;. Each sediment sample (25 ml of sediment added with 25 ml of 0.02-m prefiltered seawater) was incubated with mitomycin C (1 g ml Ϫ1 final concentration in 0.02-m prefiltered seawater).…”

Section: Methodsmentioning

confidence: 99%

Virus production and life strategies in aquatic sediments

Danovaro

2004

Limnology & Oceanography

114

146

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Aquatic sediments host much of the bacterial biomass and biodiversity and play a key role in biogeochemical cycles. However, the potential effect of viral infection remains unknown. We present estimates of virus production in a variety of benthic habitats of the Mediterranean Sea, characterized by different contamination levels and trophic states. Viriobenthos abundance in aquatic sediments ranged 10 8 -10 9 ml Ϫ1 of sediment and was ϳ20 times higher than virioplankton abundance. Vertical profiles in sediment cores revealed large virus numbers at 1-m depth below the sediment surface. Virus production in both marine and freshwater sediments was 1-2 orders of magnitude higher than typical values reported for virioplankton (0.13-1.60 ϫ 10 8 virus-like particles ml Ϫ1 sediment h Ϫ1 ), which indicates that virus turnover and infection rates can be higher in aquatic sediments than in the water column. Eutrophic and contaminated sediments displayed the highest virus production rates. Virus production was significantly correlated with the abundance of active bacteria and with bacterial cell production. We estimated an average burst size (BS) of 15-18 in marine and freshwater sediments. Virus-mediated bacterial mortality was high (on average, Ͼ40% of bacterial production) and increased from surface to deeper sediment levels, down to 100-cm depth. The fraction of bacteria with lysogenic infection (range, 0.0-1.8%) increased in deeper sediment layers (3.3% at 100-cm depth). Our results suggest that high benthic virus production rates can have a significant effect on benthic bacterial dynamics and indicate that virus production should be included in biogeochemical models of aquatic sediments.

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Lysogeny in marine Synechococcus

Cited by 128 publications

References 9 publications

In situ transcriptomic analysis of the globally important keystone N2-fixing taxon Crocosphaera watsonii

In situ transcriptomic analysis of the globally important keystone N2-fixing taxon Crocosphaera watsonii

Viruses: agents of coral disease?

Virus production and life strategies in aquatic sediments

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