Isolation and Physiological Characterization of a New Algicidal Virus Infecting the Harmful Dinoflagellate Heterocapsa pygmaea

Kim, Jin Joo; Kim, Chang Hoon; Takano, Yoshihito; Jang, In Kwon; Kim, Si Wouk; Choi, Tae Hee

doi:10.5423/ppj.nt.07.2012.0093

Cited by 8 publications

(4 citation statements)

References 23 publications

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“…Following the cryopreservation procedures of other algal virus researchers [ 13 – 16 ], we investigated the cryo-potential of the PBCV-1 particle. Cryoprotectant alone treatments elicited a lethal effect: ~87% of the infectious virus particles were inactivated in the presence of these chemicals following 24 hr exposure at 4°C.…”

Section: Resultsmentioning

confidence: 99%

“…Researchers investigated a combination of cryoprotectants and storage temperatures with the highest recovery (8.3% of infectious virus) employing flash freezing of HaV particles suspended in 20% DMSO. This protocol has been adapted for a handful of other algal viruses with viable recovery ranging from < 1% to 27% [ 14 – 16 ]. The typical low recovery in these procedures is likely due to physiological differences between viruses and cells including differences in permeability, osmolarity tolerance, and toxicity to osmoprotectants.…”

Section: Introductionmentioning

confidence: 99%

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Cryopreservation of Paramecium bursaria Chlorella Virus-1 during an active infection cycle of its host

et al. 2019

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Best practices in laboratory culture management often include cryopreservation of microbiota, but this can be challenging with some virus particles. By preserving viral isolates researchers can mitigate genetic drift and laboratory-induced selection, thereby maintaining genetically consistent strains between experiments. To this end, we developed a method to cryopreserve the model, green-alga infecting virus, Paramecium bursaria Chlorella virus 1 (PBCV-1). We explored cryotolerance of the infectivity of this virus particle, whereby freezing without cryoprotectants was found to maintain the highest infectivity (~2.5%). We then assessed the cryopreservation potential of PBCV-1 during an active infection cycle in its Chlorella variabilis NC64A host, and found that virus survivorship was highest (69.5 ± 16.5%) when the infected host is cryopreserved during mid-late stages of infection (i.e., coinciding with virion assembly). The most optimal condition for cryopreservation was observed at 240 minutes post-infection. Overall, utilizing the cell as a vehicle for viral cryopreservation resulted in 24.9–30.1 fold increases in PBCV-1 survival based on 95% confidence intervals of frozen virus particles and virus cryopreserved at 240 minutes post-infection. Given that cryoprotectants are often naturally produced by psychrophilic organisms, we suspect that cryopreservation of infected hosts may be a reliable mechanism for virus persistence in non-growth permitting circumstances in the environment, such as ancient permafrosts.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cryopreservation of Paramecium bursaria Chlorella Virus-1 during an active infection cycle of its host

et al. 2019

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show abstract

“…Following the cryopreservation procedures of other algal virus researchers (13–16), we investigated the cryo-potential of the PBCV-1 lysate. Cryoprotectant alone treatments elicited a lethal effect: ~87% of the infectious virus particles were inactivated in the presence of these chemicals following 24 hr exposure at 4° C. Given this effect, we decided to freeze PBCV-1 lysate at −150° C without any cryoprotectants.…”

Section: Resultsmentioning

confidence: 99%

Cryopreservation of Paramecium bursaria Chlorella Virus-1 during an active infection cycle of its host

Coy¹,

Alsante

Etten³

et al. 2019

Preprint

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20Best practices in laboratory culture management often include cryopreservation of microbiota, but 21 this can be challenging with some virus particles. By preserving viral isolates researchers can mitigate 22 genetic drift and laboratory-induced selection, thereby maintaining genetically consistent strains between 23 experiments. To this end, we developed a method to cryopreserve the model, green-alga infecting virus, 24 Paramecium bursaria Chlorella virus 1 (PBCV-1). We explored cryotolerance of the infectivity of this virus 25 particle, whereby freezing without cryoprotectants was found to maintain the highest infectivity (~2.5%). 26We then assessed the cryopreservation potential of PBCV-1 during an active infection cycle in its Chlorella 27 variabilis NC64A host, and found that virus survivorship was highest (69.5 ± 16.5 %) when the infected host 28 is cryopreserved during mid-late stages of infection (i.e., coinciding with virion assembly). The most 29 optimal condition for cryopreservation was observed at 240 minutes post-infection. Overall, utilizing the 30 cell as a vehicle for viral cryopreservation resulted in 24.9 -30.1 fold increases in PBCV-1 survival based 31 on 95% confidence intervals of frozen virus particles and virus cryopreserved at 240 minutes post-infection.32 Given that cryoprotectants are often naturally produced by psychrophilic organisms, we suspect that 33 cryopreservation of infected hosts may be a reliable mechanism for virus persistence in non-growth 34 permitting circumstances in the environment, such as ancient permafrosts. 35 Introduction 36Viruses are abundant components of all biological systems and they likely infect every lineage of 37 eukaryotic algae. Their impact is most readily noticed following infection and lysis of abundant bloom 38 forming algae (1-3), though lytic activity of all algal viruses contributes to significant biomass recycling via 39 the 'viral shunt' (4). To date, 65 eukaryotic algal viruses have been isolated and developed as laboratory 40 strains (5, 6). Most of these are maintained through serial propagation on their respective hosts. Though 41 this has been effective for culturing many strains over the last few decades (7, 8), each passage allows for 42 genetic mutations that can accumulate in a population (9), leading to a deviation from a standard 'wild-43 type.' Moreover, it is imperative to control evolution following the development of genetically tractable 44 algal hosts (10) and (ultimately) virus systems. A protocol for successful virus cryobiological preservation 45 would offer an opportunity to maintain genotypically consistent virus stocks. 46Cryopreservation is not a new concept in biological sciences. For most protocols, it involves 47 controlled cooling of biota to sub-freezing temperatures to achieve biological cessation while preserving 48 viability. This most often manifests as slow-cooling at a rate of 1° C / min in the presence of 49 osmoprotectant(s) (e.g., dimethylsulfoxide (DMSO), glycerol) for long-term storage at -130° C or bel...

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“…It is notable that a recent analysis of DNA mismatch repair genes (MutS) in several dsDNA algal viruses including CeV, HcDNAV, PoV, and PpV (Ogata et al, 2011) provided additional evidence supporting the hypothesis that these algal viruses are more closely related to mimiviruses than to phycodnaviruses. On the other hand, based on several diagnostic characteristics, the most recently discovered dsDNA dinoflagellate virus which infects Heterocapsa pygmaea, HpygDNAV, was considered a putative phycodnavirus (Kim et al, 2012). Because its genome awaits detailed characterization, however, this suggested classification is tentative.…”

Section: Raphidovirusmentioning

confidence: 99%

Diversity of Viruses Infecting Eukaryotic Algae

Short¹,

Staniewski²,

Chaban³

et al. 2020

Current Issues in Molecular Biology

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Algae are photosynthetic organisms that drive aquatic ecosystems, e.g. fuelling food webs or forming harmful blooms. The discovery of viruses that infect eukaryotic algae has raised many questions about their influence on aquatic primary production and their role in algal ecology and evolution. Although the full extent of algal virus diversity is still being discovered, this review summarizes current knowledge of this topic. Where possible, formal taxonomic classifications are referenced from the International Committee on Taxonomy of Viruses (ICTV); since the pace of virus discovery has far surpassed the rate of formal classification, however, numerous unclassified viruses are discussed along with their classified relatives. In total, we recognized 61 distinct algal virus taxa with highly variable morphologies that include dsDNA, ssDNA, dsRNA, and ssRNA genomes ranging from approximately 4.4 to 560 kb, with virion sizes from approximately 20 to 210 nm in diameter. These viruses infect a broad range of algae and, although there are a few exceptions, they are generally lytic and highly species or strain specific. Dedicated research efforts have led to the appreciation of algal viruses as diverse, dynamic, and ecologically important members of the biosphere, and future investigations will continue to reveal the full extent of their diversity and impact.

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Isolation and Physiological Characterization of a New Algicidal Virus Infecting the Harmful Dinoflagellate Heterocapsa pygmaea

Cited by 8 publications

References 23 publications

Cryopreservation of Paramecium bursaria Chlorella Virus-1 during an active infection cycle of its host

Cryopreservation of Paramecium bursaria Chlorella Virus-1 during an active infection cycle of its host

Cryopreservation of Paramecium bursaria Chlorella Virus-1 during an active infection cycle of its host

Diversity of Viruses Infecting Eukaryotic Algae

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