Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 14 of 14

Full-Text Articles in Life Sciences

Signaling Via Camp In Fungi: Interconnections With Mitogen-Activated Protein Kinase Pathways, James Kronstad, Adriana De Maria, Deanna Funnell, R. David Laidlaw, Nancy Lee, Mário Moniz De Sá, Marilee Ramesh Oct 1998

Signaling Via Camp In Fungi: Interconnections With Mitogen-Activated Protein Kinase Pathways, James Kronstad, Adriana De Maria, Deanna Funnell, R. David Laidlaw, Nancy Lee, Mário Moniz De Sá, Marilee Ramesh

Department of Plant Pathology: Faculty Publications

The cAMP signal transduction pathway controls a wide variety of processes in fungi. For example, considerable progress has been made in describing the involvement of cAMP pathway components in the control of morphogenesis in Saccharomyces cerevisiae, Ustilago maydis, and Magnaporthe grisea. These morphological processes include the establishment of filamentous growth in S. cerevisiae and U. maydis, and the differentiation of an appressorial infection structure in M. grisea. The discovery that appressorium formation requires cAMP signaling provides an immediate connection to fungal virulence. This connection may have broader implications among fungal pathogens because recent work indicates …


A Sensitive Elisa For Pythium Ultimum Using Polyclonal And Species-Specific Monoclonal Antibodies, G. Y. Yuen, J. Q. Xia, C. L. Sutula Sep 1998

A Sensitive Elisa For Pythium Ultimum Using Polyclonal And Species-Specific Monoclonal Antibodies, G. Y. Yuen, J. Q. Xia, C. L. Sutula

Department of Plant Pathology: Faculty Publications

A double-antibody sandwich indirect enzyme-linked immunosorbent assay (ELISA) was developed for the detection and quantification of Pythium ultimum. A polyclonal antibody produced to cell walls of P. ultimum was used as the capture antibody, while a P. ultimum-specific monoclonal antibody (MAb E5) was used for recognition of the fungus. In the ELISA, culture extracts of 7 isolates of P. ultimum exhibited strong positive reactions, whereas none of the 37 isolates of other Pythium spp. and fungal genera had positive reactions. P. ultimum was detected by ELISA in roots of bean, cabbage, and sugar beet seedlings grown in pathogen-infested …


Interactions Between The Structural Domains Of The Rna Replication Proteins Of Plant-Infecting Rna Viruses, Erin K. O'Reilly, Zhaohui Wang, Roy C. French, C. Cheng Kao Sep 1998

Interactions Between The Structural Domains Of The Rna Replication Proteins Of Plant-Infecting Rna Viruses, Erin K. O'Reilly, Zhaohui Wang, Roy C. French, C. Cheng Kao

Department of Plant Pathology: Faculty Publications

Brome mosaic virus (BMV), a positive-strand RNA virus, encodes two replication proteins: the 2a protein, which contains polymerase-like sequences, and the 1a protein, with N-terminal putative capping and C-terminal helicase-like sequences. These two proteins are part of a multisubunit complex which is necessary for viral RNA replication. We have previously shown that the yeast two-hybrid assay consistently duplicated results obtained from in vivo RNA replication assays and biochemical assays of protein-protein interaction, thus permitting the identification of additional interacting domains. We now map an interaction found to take place between two 1a proteins. Using previously characterized 1a mutants, a perfect …


A Partial Host Range Of The High Plains Virus Of Corn And Wheat, Dallas L. Seifers, Tom L. Harvey, T. J. Martin, Stanley G. Jensen Aug 1998

A Partial Host Range Of The High Plains Virus Of Corn And Wheat, Dallas L. Seifers, Tom L. Harvey, T. J. Martin, Stanley G. Jensen

Department of Plant Pathology: Faculty Publications

Barley (Hordeum vulgare), cheat (Bromus secalinus), corn (Zea mays), oat (Avena sativa), rye (Secale cereale), and wheat (Triticum aestivum) were infected by a Kansas isolate of the High Plains virus (HPV) in greenhouse experiments, but several other grass species were not. Infection of a host was dependent upon wheat curl mite numbers. Although both green foxtail (Setaria viridis) and yellow foxtail (S. glauca) are found naturally infected by HPV, only yellow foxtail could be infected in greenhouse experiments. Field sampling (1994 to 1996) of …


Certification And The American Phytopathological Society, L. J. Stowell, J. Amador, O.W. Barnett, R. J. Cook, D. E. Mathre, A. K. Vidaver, S. A. Tolin Aug 1998

Certification And The American Phytopathological Society, L. J. Stowell, J. Amador, O.W. Barnett, R. J. Cook, D. E. Mathre, A. K. Vidaver, S. A. Tolin

Department of Plant Pathology: Faculty Publications

The profession of plant pathology strives to improve the health and safety of the public through improved plant health systems. This includes the benefits afforded by well-managed urban landscapes and abundant food and fiber. However, the proud glow of the profession of plant pathology has dimmed over the past 20 years to the point that some members of the American Phytopathological Society (APS), the principal professional society of plant pathologists in the United States, are not sure what a plant pathologist should know or what a plant pathologist is responsible for (Phytopathology News 30:162). Without a unified, positive direction for …


Phylogenetic Relationships Within The Family Potyviridae: Wheat Streak Mosaic Virus And Brome Streak Mosaic Virus Are Not Members Of The Genus Rymovirus, Drake C. Stenger, Jeffrey S. Hall, Il-Ryong Choi, Roy C. French Jul 1998

Phylogenetic Relationships Within The Family Potyviridae: Wheat Streak Mosaic Virus And Brome Streak Mosaic Virus Are Not Members Of The Genus Rymovirus, Drake C. Stenger, Jeffrey S. Hall, Il-Ryong Choi, Roy C. French

Department of Plant Pathology: Faculty Publications

The complete nucleotide sequence of wheat streak mosaic virus (WSMV) has been determined based on complementary DNA clones derived from the 9,384-nucleotide (nt) RNA of the virus. The genome of WSMV has a 130-nt 5&#;&#;leader and 149-nt 3&#;-untranslated region and is polyadenylated at the 3&#;&#;end. WSMV RNA encodes a single polyprotein of 3,035 amino acid residues and has a deduced genome organization typical for a member of the family Potyviridae (5&#;-P1/HC-Pro/P3/6K1/CI/6K2/VPg-NIa/NIb/CP-3&#;). Because WSMV shares with ryegrass mosaic virus (RGMV) the biological property of transmission by eriophyid mites, WSMV has been assigned to the genus Rymovirus, of which RGMV is …


Expression Of Human Lactoferrin Cdna Confers Resistance To Ralstonia Solanacearum In Transgenic Tobacco Plants, Zhanyuan Zhang, Dermot P. Coyne, Anne K. Vidaver, Amitava Mitra Jun 1998

Expression Of Human Lactoferrin Cdna Confers Resistance To Ralstonia Solanacearum In Transgenic Tobacco Plants, Zhanyuan Zhang, Dermot P. Coyne, Anne K. Vidaver, Amitava Mitra

Department of Plant Pathology: Faculty Publications

A construct containing a human lactoferrin cDNA was used to transform tobacco (Nicotiana tabacum) using an Agrobacterium-mediated DNA-transfer system to express this human protein in transgenic plants. Transformants were analyzed by Southern, Northern, and Western blots to determine integration of the cDNA into the plant genome and lactoferrin gene expression levels. Most transgenic plants demonstrated significant delays of bacterial wilt symptoms when inoculated with the bacterial pathogen Ralstonia solanacearum. Quantification of the expressed lactoferrin protein by enzyme-linked immunosorbent assay in transgenic plants indicated a significant positive relationship between lactoferrin gene expression levels and levels of disease …


Physiologic Specialization Of Puccinia Recondita F. Sp. Tritici In Nebraska During 1995 And 1996, J. E. Watkins, S. S. Rutledge, P. Stephen Baenziger, W. Youngquist Jun 1998

Physiologic Specialization Of Puccinia Recondita F. Sp. Tritici In Nebraska During 1995 And 1996, J. E. Watkins, S. S. Rutledge, P. Stephen Baenziger, W. Youngquist

Department of Plant Pathology: Faculty Publications

Field samples of Puccinia recondita f. sp. tritici, collected from four wheat-growing regions in Nebraska in 1995 and from three in 1996, were characterized for virulence. Twenty virulence phenotypes were identified in 1995 and 18 in 1996. Virulence phenotypes MBR-10,18 (virulent on Lr genes, 1, 3, 3ka, 10, 11, 18, and 30) and MDR-10,18 (virulent on Lr genes 1, 3, 3ka, 10, 11, 18, 24, and 30) were the most prevalent, with each phenotype comprising 21.6% of the isolates characterized in 1995. Of the 1995 isolates, 24% were virulent on 10 or more host genes. No virulence to Lr16 and …


Polymerase Chain Reaction Detection And Phylogenetic Characterization Of An Agent Associated With Yellow Vine Disease Of Cucurbits, Francisco J. Avila, Benny D. Bruton, Jacqueline Fletcher, J. L. Sherwood, Sam D. Pair, Ulrich Melcher May 1998

Polymerase Chain Reaction Detection And Phylogenetic Characterization Of An Agent Associated With Yellow Vine Disease Of Cucurbits, Francisco J. Avila, Benny D. Bruton, Jacqueline Fletcher, J. L. Sherwood, Sam D. Pair, Ulrich Melcher

Department of Plant Pathology: Faculty Publications

Diagnosis of yellow vine disease (YVD) in cucurbits, an important disease in the south-central United States, relies on external symptom appearance, phloem discoloration, and the presence of bacterium-like organisms (BLOs) in phloem. Polymerase chain reaction (PCR) amplification of BLO nucleotide sequences was explored as a means to improve diagnostic techniques. PCR, using a primer pair based on sequences of the citrus-greening BLO, amplified a 0.15-kilobase (kb) fragment from the DNA of symptomatic plants, but not from that of asymptomatic plants. Its nucleotide sequence suggested that the DNA amplified was of prokaryotic origin. A primer pair, designed to amplify nonspecific prokaryotic …


Characterization Of The Large (L) Rna Of Peanut Bud Necrosis Tospovirus, S. Gowda, Satyanarayana Tatineni, R. A. Naidu, A. Mushegian, W. O. Dawson, D. V. R. Reddy Jan 1998

Characterization Of The Large (L) Rna Of Peanut Bud Necrosis Tospovirus, S. Gowda, Satyanarayana Tatineni, R. A. Naidu, A. Mushegian, W. O. Dawson, D. V. R. Reddy

Department of Plant Pathology: Faculty Publications

The nucleocapsids purified from peanut plants systemically infected with peanut bud necrosis virus (PBNV), a member of the genus Tospovirus, contained both viral(v) and viral complementary(vc) sense L RNAs. Defective forms of L RNA containing ‘core polymerase region’ were observed. The full length L RNA of PBNV was sequenced using overlapping cDNA clones. The 8911 nucleotide L RNA contains a single open reading frame (ORF) in the vc strand, and encodes a protein of 330 kDa. At the 50 and 30 termini of the v sense RNA there were 247 and 32 nt untranslated regions, respectively, containing an 18 …


A Phylogenetic Analysis Of Heterorhabditis (Nemata: Rhabditidae) Based On Internal Transcribed Spacer 1 Dna Sequence Data, B. J. Adams, A. M. Burnell, Thomas O. Powers Jan 1998

A Phylogenetic Analysis Of Heterorhabditis (Nemata: Rhabditidae) Based On Internal Transcribed Spacer 1 Dna Sequence Data, B. J. Adams, A. M. Burnell, Thomas O. Powers

Department of Plant Pathology: Faculty Publications

Internal transcribed spacer 1 sequences were used to infer phylogenetic relationships among 8 of the 9 described species and one putative species of the entomopathogenic nematode genus Heterorhabditis. Sequences were aligned and optimized based on pairwise genetic distance and parsimony criteria and subjected to a variety of sequence alignment parameters. Phylogenetic trees were constructed with maximum parsimony, cladistic, distance, and maximum likelihood algorithms. Our results gave strong support for four pairs of sister species, while relationships between these pairs also were resolved but less well supported. The ITS1 region of the nuclear ribosomal repeat was a reliable source of …


Lindsay M. Black, 1907 To 1997, Myron K. Brakke, D. V. R. Reddy Jan 1998

Lindsay M. Black, 1907 To 1997, Myron K. Brakke, D. V. R. Reddy

Department of Plant Pathology: Faculty Publications

Plant pathology and virology lost a pioneer when Lindsay MacLeod Black died on 23 December 1997. We lost a friend and mentor. Black was noted for proving conclusively that a plant virus can multiply in both leafhopper vectors and plants; characterizing unstable, leafhopper-transmitted viruses; and developing insect tissue cultures for studying plant viruses.


Signaling Via Camp In Fungi: Interconnections With Mitogen-Activated Protein Kinase Pathways, James Kronstad, Adriana De Maria, Deanna L. Funnell, R. David Laidlaw, Nancy Lee, Mário Moniz De Sá, Marilee Ramesh Jan 1998

Signaling Via Camp In Fungi: Interconnections With Mitogen-Activated Protein Kinase Pathways, James Kronstad, Adriana De Maria, Deanna L. Funnell, R. David Laidlaw, Nancy Lee, Mário Moniz De Sá, Marilee Ramesh

Department of Plant Pathology: Faculty Publications

The cAMP signal transduction pathway controls a wide variety of processes in fungi. For example, considerable progress has been made in describing the involvement of cAMP pathway components in the control of morphogenesis in Saccharomyces cerevisiae, Ustilago maydis, and Magnaporthe grisea. These morphological processes include the establishment of filamentous growth in S. cerevisiae and U. maydis, and the differentiation of an appressorial infection structure in M. grisea. The discovery that appressorium formation requires cAMP signaling provides an immediate connection to fungal virulence. This connection may have broader implications among fungal pathogens because recent work indicates that …


Peanut Yellow Spot Virus Is A Member Of A New Serogroup Of Tospovirus Genus Based On Small (S) Rna Sequence And Organization, Satyanarayana Tatineni, S. Gowda, K. Lakshminarayana Reddy, S. E. Mitchell, W. O. Dawson, D. V. R. Reddy Jan 1998

Peanut Yellow Spot Virus Is A Member Of A New Serogroup Of Tospovirus Genus Based On Small (S) Rna Sequence And Organization, Satyanarayana Tatineni, S. Gowda, K. Lakshminarayana Reddy, S. E. Mitchell, W. O. Dawson, D. V. R. Reddy

Department of Plant Pathology: Faculty Publications

Peanut yellow spot virus (PYSV) represents a distinct tospovirus species based on serology and nucleic acid hybridization. The sequence of the S RNA was 2 970 nucleotides with 22 nucleotide long inverted repeats (with three mismatches) at the termini. The coding was ambisense with a long open reading frame (ORF) in each strand. The 5'-large ORF (1 440 nucleotides in the viral sense (v) strand) encoded a protein with a predicted size of 53.2 kDa that was identified as the nonstructural (NSs) protein based on 16–21% sequence identity and 42– 48% sequence similarity with other tospoviruses. A 3' ORF (741 …