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Full-Text Articles in Plant Sciences
Initial Events Associated With Virus Pbcv-1 Infection Of Chlorella Nc64a, Gerhard Thiel, Anna Moroni, David Dunigan, James L. Van Etten
Initial Events Associated With Virus Pbcv-1 Infection Of Chlorella Nc64a, Gerhard Thiel, Anna Moroni, David Dunigan, James L. Van Etten
David D Dunigan Ph. D.
Chlorella viruses (or chloroviruses) are very large, plaque-forming viruses. The viruses are multilayered structures containing a large double-stranded DNA genome, a lipid bilayered membrane, and an outer icosahedral capsid shell. The viruses replicate in certain isolates of the coccal green alga, Chlorella. Sequence analysis of the 330-kbp genome of Paramecium bursaria Chlorella virus 1 (PBCV-1), the prototype of the virus family Phycodnaviridae, reveals <365 protein-encoding genes and 11 tRNA genes. Products of about 40% of these genes resemble proteins of known function, including many that are unexpected for a virus. Among these is a virus-encoded protein, called Kcv, which forms …
Dna Viruses: The Really Big Ones (Giruses), James L. Van Etten, Leslie C. Lane, David Dunigan
Dna Viruses: The Really Big Ones (Giruses), James L. Van Etten, Leslie C. Lane, David Dunigan
David D Dunigan Ph. D.
Viruses with genomes greater than 300 kb and up to 1200 kb are being discovered with increasing frequency. These large viruses (often called giruses) can encode up to 900 proteins and also many tRNAs. Consequently, these viruses have more protein-encoding genes than many bacteria, and the concept of small particle/small genome that once defined viruses is no longer valid. Giruses infect bacteria and animals although most of the recently discovered ones infect protists. Thus, genome gigantism is not restricted to a specific host or phylogenetic clade. To date, most of the giruses are associated with aqueous environments. Many of these …
Chlorovirus: A Genus Of Phycodnaviridae That Infects Certain Chlorella-Like Green Algae, Ming Kang, David Dunigan, James L. Van Etten
Chlorovirus: A Genus Of Phycodnaviridae That Infects Certain Chlorella-Like Green Algae, Ming Kang, David Dunigan, James L. Van Etten
David D Dunigan Ph. D.
Taxonomy: Chlorella viruses are assigned to the family Phycodnaviridae, genus Chlorovirus, and are divided into three species: Chlorella NC64A viruses, Chlorella Pbi viruses and Hydra viridis Chlorella viruses. Chlorella viruses are large, icosahedral, plaque-forming, dsDNA viruses that infect certain unicellular, chlorella-like green algae. The type member is Paramecium bursaria chlorella virus 1 (PBCV-1).
Physical properties: Chlorella virus particles are large (molecular weight ~1 × 109 Da) and complex. The virion of PBCV-1 contains more than 100 different proteins; the major capsid protein, Vp54, comprises ~40% of the virus protein. Cryoelectron microscopy and three-dimensional image reconstruction of PBCV-1 virions …
'Earlibrite' Strawberry, C. K. Chandler, D. E. Legard, David Dunigan, T. E. Crocker, C. A. Sims
'Earlibrite' Strawberry, C. K. Chandler, D. E. Legard, David Dunigan, T. E. Crocker, C. A. Sims
David D Dunigan Ph. D.
There is a need in west central Florida and other winter strawberry (Fragaria xananassa Duchesne) production areas for an early ripening cultivar to replace or be an alternative to 'Sweetcharlie' (Chandleretal., 1997a). 'Sweet Charlie' has benefitted the Florida strawberry industry through its relatively high production of fruit early in the season, when market prices are generally high. But the average fruit size is small, and the texture of its fruit is often soft, making shipment and shelf life of 'Sweet Charlie' problematic. 'Earlibrite' strawberry has produced high early-season (December through February) yields of large, flavorful fruit at the Univ. of …
Phycodnaviruses: A Peek At Genetic Diversity, David Dunigan, Lisa Fitzgerald, James L. Van Etten
Phycodnaviruses: A Peek At Genetic Diversity, David Dunigan, Lisa Fitzgerald, James L. Van Etten
David D Dunigan Ph. D.
The family Phycodnaviridae encompasses a diverse collection of large icosahedral, dsDNA viruses infecting algae. These viruses have genomes ranging from 160 to 560 kb. The family consists of six genera based initially on host range and supported by sequence comparisons. The family is monophyletic with branches for each genus, but the phycodnaviruses have evolutionary roots that connect with several other families of large DNA viruses, referred to as the nucleocytoplasmic large DNA viruses (NCLDV). The genomes of members in three genera in the Phycodnaviridae have recently been sequenced and the purpose of this manuscript is to summarize these data. The …
Microarray Analysis Of Paramecium Bursaria Chlorella Virus 1 Transcription, Giane M. Yanai-Balser, Garry A. Duncan, James D. Eudy, Dong Wang, Xiao Li, Irina V. Agarkova, David Dunigan, James L. Van Etten
Microarray Analysis Of Paramecium Bursaria Chlorella Virus 1 Transcription, Giane M. Yanai-Balser, Garry A. Duncan, James D. Eudy, Dong Wang, Xiao Li, Irina V. Agarkova, David Dunigan, James L. Van Etten
David D Dunigan Ph. D.
Paramecium bursaria chlorella virus 1 (PBCV-1), a member of the family Phycodnaviridae, is a large double-stranded DNA, plaque-forming virus that infects the unicellular green alga Chlorella sp. strain NC64A. The 330-kb PBCV-1 genome is predicted to encode 365 proteins and 11 tRNAs. To monitor global transcription during PBCV-1 replication, a microarray containing 50-mer probes to the PBCV-1 365 protein-encoding genes (CDSs) was constructed. Competitive hybridization experiments were conducted by using cDNAs from poly(A)- containing RNAs obtained from cells at seven time points after virus infection. The results led to the following conclusions: (i) the PBCV-1 replication cycle is temporally programmed …
The Chlorella Variabilis Nc64a Genome Reveals Adaptation To Photosymbiosis, Coevolution With Viruses, And Cryptic Sex, Guillaume Blanc, Gary Duncan, Irina Agarkova, Mark Borodovsky, James Gurnon, Alan Kuo, Erika Lindquist, Susan Lucas, Jasmyn Pangilinan, Juergen Polle, Asaf Salamov, Astrid Terry, Takashi Yamada, David Dunigan, Igor Grigoriev, Jean-Michel Claverie, James Van Etten
The Chlorella Variabilis Nc64a Genome Reveals Adaptation To Photosymbiosis, Coevolution With Viruses, And Cryptic Sex, Guillaume Blanc, Gary Duncan, Irina Agarkova, Mark Borodovsky, James Gurnon, Alan Kuo, Erika Lindquist, Susan Lucas, Jasmyn Pangilinan, Juergen Polle, Asaf Salamov, Astrid Terry, Takashi Yamada, David Dunigan, Igor Grigoriev, Jean-Michel Claverie, James Van Etten
David D Dunigan Ph. D.
Chlorella variabilis NC64A, a unicellular photosynthetic green alga (Trebouxiophyceae), is an intracellular photobiont of Paramecium bursaria and a model system for studying virus/algal interactions. We sequenced its 46-Mb nuclear genome, revealing an expansion of protein families that could have participated in adaptation to symbiosis. NC64A exhibits variations in GC content across its genome that correlate with global expression level, average intron size, and codon usage bias. Although Chlorella species have been assumed to be asexual and nonmotile, the NC64A genome encodes all the known meiosis-specific proteins and a subset of proteins found in flagella. We hypothesize that Chlorella might have …
Fungal Symbiosis From Mutualism To Parasitism: Who Controls The Outcome, Host Or Invader?, Regina S. Redman, David Dunigan, Rusty J. Rodriguez
Fungal Symbiosis From Mutualism To Parasitism: Who Controls The Outcome, Host Or Invader?, Regina S. Redman, David Dunigan, Rusty J. Rodriguez
David D Dunigan Ph. D.
• Plant symbiotic fungi are generally thought to express a single lifestyle that might increase (mutualism), decrease (parasitism), or have no influence (commensalism) on host fitness. However, data are presented here demonstrating that plant pathogenic Colletotrichum species are able to asymptomatically colonize plants and express nonpathogenic lifestyles. • Experiments were conducted in growth chambers and plant colonization was assessed by emergence of fungi from surface sterilized plant tissues. Expression of symbiotic lifestyles was assessed by monitoring the ability of fungi to confer disease resistance, drought tolerance and growth enhancement. • Several pathogenic Colletotrichum species expressed either mutualistic or commensal lifestyles …
‘Strawberry Festival’ Strawberry, C. K. Chandler, D. E. Legard, David Dunigan, T. E. Crocker, C. A. Sims
‘Strawberry Festival’ Strawberry, C. K. Chandler, D. E. Legard, David Dunigan, T. E. Crocker, C. A. Sims
David D Dunigan Ph. D.
Most of the strawberries (Fragaria xananassa Duchesne) produced in Florida are shipped fresh to locations throughout the eastern United States and Canada (Florida Agricultural Statistics [www.nass.usda.gov/ fl]). Therefore, Florida growers need cultivars that produce fruit that are attractive and flavorful, and maintain these qualities during and after long-distance shipment. 'Strawberry Festival' strawberry has produced commercially acceptable yields of firm, attractive, and flavorful fruit in trials at the Univ. of Florida's Gulf Coast Research and Education Center in Dover (GCREC-Dover) and in two commercial fields in west central Florida. It is recommended for trial in areas where strawberries are grown in …
The Genome Of The Polar Eukaryotic Microalga Coccomyxa Subellipsoidea Reveals Traits Of Cold Adaptation, Guillaume Blanc, Irina Agarkova, Jane Grimwood, Alan Kuo, Andrew Brueggeman, David Dunigan, James Gurnon, Istvan Ladunga, Erika Lindquist, Susan Lucas, Jasmyn Pangilinan, Thomas Pröschold, Asaf Salamov, Jeremy Schmutz, Donald Weeks, Takashi Yamada, Alexandre Lomsadze, Mark Borodovsky, Jean-Michel Claverie, Igor Grigoriev, James L. Van Etten
The Genome Of The Polar Eukaryotic Microalga Coccomyxa Subellipsoidea Reveals Traits Of Cold Adaptation, Guillaume Blanc, Irina Agarkova, Jane Grimwood, Alan Kuo, Andrew Brueggeman, David Dunigan, James Gurnon, Istvan Ladunga, Erika Lindquist, Susan Lucas, Jasmyn Pangilinan, Thomas Pröschold, Asaf Salamov, Jeremy Schmutz, Donald Weeks, Takashi Yamada, Alexandre Lomsadze, Mark Borodovsky, Jean-Michel Claverie, Igor Grigoriev, James L. Van Etten
David D Dunigan Ph. D.
Background: Little is known about the mechanisms of adaptation of life to the extreme environmental conditions encountered in polar regions. Here we present the genome sequence of a unicellular green alga from the division chlorophyta, Coccomyxa subellipsoidea C-169, which we will hereafter refer to as C-169. This is the first eukaryotic microorganism from a polar environment to have its genome sequenced. Results: The 48.8 Mb genome contained in 20 chromosomes exhibits significant synteny conservation with the chromosomes of its relatives Chlorella variabilis and Chlamydomonas reinhardtii. The order of the genes is highly reshuffled within synteny blocks, suggesting that intra-chromosomal rearrangements …
Chlorovirus-Mediated Membrane Depolarization Of Chlorella Alters Secondary Active Transport Of Solutes, Irina V. Agarkova, David Dunigan, James R. Gurnon, Timo Greiner, Julia Barres, Gerhard Thiel, James L. Van Etten
Chlorovirus-Mediated Membrane Depolarization Of Chlorella Alters Secondary Active Transport Of Solutes, Irina V. Agarkova, David Dunigan, James R. Gurnon, Timo Greiner, Julia Barres, Gerhard Thiel, James L. Van Etten
David D Dunigan Ph. D.
Paramecium bursaria chlorella virus 1 (PBCV-1) is the prototype of a family of large, double-stranded DNA, plaque-forming viruses that infect certain eukaryotic chlorella-like green algae from the genus Chlorovirus. PBCV-1 infection results in rapid host membrane depolarization and potassium ion release. One interesting feature of certain chloroviruses is that they code for functional potassium ion-selective channel proteins (Kcv) that are considered responsible for the host membrane depolarization and, as a consequence, the efflux of potassium ions. This report examines the relationship between cellular depolarization and solute uptake. Annotation of the virus host Chlorella strain NC64A genome revealed 482 putative transporter-encoding …
Bcl-2 Family Members Inhibit Oxidative Stress-Induced Programmed Cell Death In Saccharomyces Cerevisiae, Shao-Rong Chen, David Dunigan, Martin Dickman
Bcl-2 Family Members Inhibit Oxidative Stress-Induced Programmed Cell Death In Saccharomyces Cerevisiae, Shao-Rong Chen, David Dunigan, Martin Dickman
David D Dunigan Ph. D.
Selected antiapoptotic genes were expressed in baker’s yeast (Saccharomyces cerevisiae) to evaluate cytoprotective effects during oxidative stress. When exposed to treatments resulting in the generation of reactive oxygen species (ROS), including H2O2, menadione, or heat shock, wild-type yeast died and exhibited apoptotic-like characteristics, consistent with previous studies. Yeast strains were generated expressing nematode ced-9, human bcl-2, or chicken bcl-xl genes. These transformants tolerated a range of oxidative stresses, did not display features associated with apoptosis, and remained viable under conditions that were lethal to wildtype yeast. Yeast strains expressing a mutant antiapoptotic gene (bcl-2 Δα 5-6), known to be nonfunctional …
Capping Of Tobacco Mosaic Virus Rna: Analysis Of Viral-Coded Guanylyltransferase-Like Activity, David Dunigan, Milton Zaitlin
Capping Of Tobacco Mosaic Virus Rna: Analysis Of Viral-Coded Guanylyltransferase-Like Activity, David Dunigan, Milton Zaitlin
David D Dunigan Ph. D.
The 5’ end of tobacco mosaic virus (TMV) genomic RNA is capped with 7- methylguanosine. A virus-coded polypeptide with guanylyltransferase activity has been investigated. This enzyme is responsible for forming the 5’→5’ linkage of guanosine 5’-monophosphate to the 5’- diphosphate of an acceptor RNA, thereby forming the cap. A critical step in the mechanism for cap formation in the eukaryotic nucleus is for guanylyltransferase to bind covalently to guanosine 5’- monophosphate with the hydrolysis of pyrophosphate when guanosine 5’- triphosphate is the substrate. The TMV 126-kilodalton protein, which is most probably a component of the TMV replicase, was found to …
Cloning Of Nt.Cviqii Nicking Endonuclease And Its Cognate Methyltransferase: M.Cviqii Methylates Ag Sequence, Siu-Hong Chan, Zhenyu Zhu, David Dunigan, James L. Van Etten, Shuang-Yong Xu
Cloning Of Nt.Cviqii Nicking Endonuclease And Its Cognate Methyltransferase: M.Cviqii Methylates Ag Sequence, Siu-Hong Chan, Zhenyu Zhu, David Dunigan, James L. Van Etten, Shuang-Yong Xu
David D Dunigan Ph. D.
Chlorella virus NY-2A has a large, highly methylated dsDNA genome (45% of the cytosines are 5-methylcytosine and 37% of the adenines are N6-methyladenine). Here, we report the cloning, expression, and characterization of the NY-2A-encoded CviQII nicking-modification (N-M) system. The nicking endonuclease, Nt.CviQII, recognizes R ↓ AG (R = A or G, ↓ indicating cleavage site) sequences and cleaves the phosphodiester bond 5′ to the adenosine. Because of the difficulty in cloning and expressing the wild-type Nt.CviQII, C-terminal truncation mutants were generated and full-length Nt.CviQII was reconstructed by intein-mediated peptide ligation. The truncation mutants and the reconstructed full-length Nt.CviQII have the …