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Full-Text Articles in Life Sciences

Chlorella Viruses Isolated In China, Yanping Zhang, Dwight Burbank, James L. Van Etten Sep 1988

Chlorella Viruses Isolated In China, Yanping Zhang, Dwight Burbank, James L. Van Etten

Department of Plant Pathology: Faculty Publications

Plaque-forming viruses of the unicellular, eucaryotic, exsymbiotic, Chlorella-like green algae strain NC64A, which are common in the United States, were also present in fresh water collected in the People's Republic of China. Seven of the Chinese viruses were examined in detail and compared with the Chlorella viruses previously isolated in the United States. Like the American viruses, the Chinese viruses were large polyhedra and sensitive to chloroform. They contained numerous structural proteins and large double-stranded DNA genomes of at least 300 kilobase pairs. Each of the DNAs from the Chinese viruses contained 5-methyldeoxycytosine, which varied from 12.6 to 46.7% …


Perspectives On Process In Plant Virology, Myron K. Brakke Jan 1988

Perspectives On Process In Plant Virology, Myron K. Brakke

Department of Plant Pathology: Faculty Publications

The editors asked that I write a chapter on landmarks in plant virology, a topic that has been covered by several authors, for example by Henderson Smith (89), Bawden (9), Holmes (51), Markham (62), Harrison (44), Black (12), and Matthews (64). In 1 938, the first of these authors, Henderson Smith (89), divided his presidential address to the Society for Applied Biology between the control of plant-virus diseases and the nature of plant viruses. Progress since then has been much more rapid in the latter than in the former area. Henderson Smith could easily understand today's literature on losses, control, …


A Non-Capsid Protein Associated With Unencapsidated Virus Rna In Barley Infected With Barley Stripe Mosaic Virus, Myron K. Brakke, E. M. Ball, W. G. Langenberg Jan 1988

A Non-Capsid Protein Associated With Unencapsidated Virus Rna In Barley Infected With Barley Stripe Mosaic Virus, Myron K. Brakke, E. M. Ball, W. G. Langenberg

Department of Plant Pathology: Faculty Publications

Barley tissue with an acute systemic infection of barley stripe mosaic virus contained a large amount of unencapsidated virus RNA which was stable in extracts made in ribosome isolation buffer. The virus RNA in ribosome preparations sedimented in a broad band at 80S to 100S in sucrose gradients, which is less than the virion sedimentation rate of 180S to 200S. A protein of apparent Mr 60 000, which sedimented with the virus RNA, was present in ribosome extracts from infected plants but absent from those from uninfected plants. The protein is probably a virus protein because its apparent molecular …


Effect Of Wheat Streak Mosaic Virus Infection On Total Dna And Chloroplast Ribosomal Rna In Wheat Leaves, Myron K. Brakke, J. L. White, R. G. Samson, J. Joshi Jan 1988

Effect Of Wheat Streak Mosaic Virus Infection On Total Dna And Chloroplast Ribosomal Rna In Wheat Leaves, Myron K. Brakke, J. L. White, R. G. Samson, J. Joshi

Department of Plant Pathology: Faculty Publications

The amount of chloroplast 23s rRNA relative to either DNA or to cytoplasmic 28s rRNA was reduced in young wheat leaves infected with wheat streak mosaic virus.
ChlorophyiJ was reduced in infected leaves. Fresh weight per leaf and DNA content per leaf were reduced in infected leaves, but DNA per g was increased.
Cytoplasmic ribosomal RN.A appeared to degrade more slowly during senescence in infected leaves than in uninfected. Virus was undetectable by density gradient centrifugation in systemicaliy infected leaves less than 6 cm long and reached its highest concentration when young leaves reached their maximum size. Mosaic developed in …


Comparisons Of Mitochondrial Dna From The Sibling Species Heterodera Glycines And H. Schachtii, A. D. Radice, Thomas O. Powers, Laurie J. Sandall, R. D. Riggs Jan 1988

Comparisons Of Mitochondrial Dna From The Sibling Species Heterodera Glycines And H. Schachtii, A. D. Radice, Thomas O. Powers, Laurie J. Sandall, R. D. Riggs

Department of Plant Pathology: Faculty Publications

Restriction fragment patterns of mitochondrial DNA from sibling species of cyst nematodes Heterodera glycines and H. schachtii were examined. Fourteen restriction endonucleases recognizing four, five, and six base-pair sequences yielded a total of 90 scorable fragments of which 10% were shared by both species. Mitochondrial genome sizes for H. glycines and H. schachtii were estimated to be 22.5-23.5 kb and 23.0 kb, respectively. A single wild type mitochondrial genome was identified in all populations of H. glycines examined, although other mitochondrial genomes were present in some populations. The H. schachtii genome exhibited 57 scorable fragments, compared with 33 identified in …


Estimation Of Genetic Divergence In Meloidogyne Mitochondrial Dna, Thomas O. Powers, Laurie J. Sandall Jan 1988

Estimation Of Genetic Divergence In Meloidogyne Mitochondrial Dna, Thomas O. Powers, Laurie J. Sandall

Department of Plant Pathology: Faculty Publications

Restriction fragments from purified mitochondrial DNA can be readily detected following rapid end-labeling with [α-32P] nucleoside triphosphates and separation by gel electropboresis. Mitochondrial DNA from 12 populations of Meloidogyne species was digested with 12 restriction enzymes producing more than 60 restriction fragments for each species. The mitochondrial genome of M. arenaria is the most genetically distinct of the four species compared. M. arenaria shows approximately 2.1-3.1% nucleotide sequence divergence from the mitochondrial genomes of M. javanica, M. incognita, and M. hapla. Among the latter three species, interspecific estimates of sequence divergence range from 0.7 to …


Chlorophyll, Chloroplast Ribosomal Rna, And Dna Are Reduced By Rarley Stripe Mosaic Virus Systemic Infection, Myron K. Brakke, J. L. White, R. G. Samson, Jay Joshi Jan 1988

Chlorophyll, Chloroplast Ribosomal Rna, And Dna Are Reduced By Rarley Stripe Mosaic Virus Systemic Infection, Myron K. Brakke, J. L. White, R. G. Samson, Jay Joshi

Department of Plant Pathology: Faculty Publications

Barley stripe mosaic virus became systemic 3 days alter inoculation of barley plants in the two-leaf stage. The first leaf to show mosaic was leaf 3. which was 4.5 cm long at 3 days after inoculation when it was invaded by virus. Since all of Ieaf 3 showed mosaic, the events leading to mosaic occurred during cell expansion and after cell division. which is limited to the basal centimeter of young cereal leaves. Molecular changes associated with mosaic formation included a 509, reduction in chloroplast ribosomal RNA and chlorophyll, expressed as amount per unit DNA, in young leaves with an …