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J W Moyer

Publications and source records attributed to J W Moyer.

13 recordsLinked to original sources
PubMed2005

The molecular population genetics of the Tomato spotted wilt virus (TSWV) genome.

RNA viruses are characterized by high genetic variability resulting in rapid adaptation to new or resistant hosts. Research for plant RNA virus genetic structure and its variability has been relatively scarce compared to abundant research done for human and animal RNA viruses. Here, we utilized a molecular population genetic framework to characterize the evolution of a highly pathogenic plant RNA virus [Tomato spotted wilt virus (TSWV), Tospovirus, Bunyaviridae]. Data from genes encoding five viral proteins were used for phylogenetic analysis, and for estimation of population parameters, subpopulation differentiation, recombination, divergence between Tospovirus species, and selective constraints on the TSWV genome. Our analysis has defined the geographical structure of TSWV, attributed possibly to founder effects. Also, we identify positive selection favouring divergence between Tospovirus species. At the species level, purifying selection has acted to preserve protein function, although certain amino acids appear to be under positive selection. This analysis provides demonstration of population structuring and species-wide population expansions in a multisegmented plant RNA virus, using sequence-based molecular population genetic analyses. It also identifies specific amino acid sites subject to selection within Bunyaviridae and estimates the level of genetic heterogeneity of a highly pathogenic plant RNA virus. The study of the variability of TSWV populations lays the foundation in the development of strategies for the control of other viral diseases in floral crops.

Base Sequence↗
PubMed2003

Seasonal dispersal patterns of Frankliniella fusca (Thysanoptera: Thripidae) and tomato spotted wilt virus occurrence in central and eastern North Carolina.

The seasonal abundance and temporal pattern of Frankliniella fusca Hinds dispersal were monitored from 1996 to 2000 at 12 locations in central and eastern North Carolina. The predominant vector species of tomato spotted wilt virus (TSWV) captured across all locations was F. fusca (98%). The temporal patterns of F. fusca dispersal observed during spring seasons varied among locations in all years except 2000. Regression analysis estimated that times of first flight in the spring seasons varied among locations, whereas flight duration intervals were similar. Temporal patterns of F. fusca captured varied significantly between aerial traps placed 0.1 and 1.0 m above the soil surface. Fewer total thrips were captured at 0.1 m, although thrips dispersal occurred earlier and over a greater time interval compared with 1.0-m traps. Temporal patterns of TSWV occurrence differed among locations in the spring seasons of 1999 and 2000, whereas patterns of virus occurrence were similar during the fall seasons. Patterns of F. filsca dispersal and subsequent TSWV occurrence were synchronous at locations in 1999 and 2000 where the greatest number of TSWV lesions was recorded. Knowledge of the temporal patterns of F. fiasca dispersal and TSWV occurrence may be a useful indicator for describing the time when susceptible crops are at highest risk of TSWV infection.

Animals↗
PubMed2001

Overcoming host- and pathogen-mediated resistance in tomato and tobacco maps to the M RNA of Tomato spotted wilt virus.

A viral genetic system was used to map the determinants of the ability of Tomato spotted wilt virus (TSWV) to overcome the R gene (Sw-5) in tomato and the resistance conferred by the nucleocapsid gene of TSWV (N gene) in tobacco. A complete set of reassortant genotypes was generated from TSWV isolates A and D. TSWV-A was able to overcome the Sw-5 gene in tomato and the TSWV N gene in tobacco, whereas TSWV-D was repressed by both forms of resistance. The ability to overcome both forms of resistance was associated with the M RNA segment of TSWV-A (M(A)). Overcoming the Sw-5 gene was linked solely to the presence of M(A), and the ability of M(A) to overcome the TSWV N gene was modified by the L RNA and the S RNA of TSWV-A, which is consistent with previous reports that suggest that the nucleocapsid gene is not the primary determinant for overcoming the nucleocapsid-mediated resistance. Sequence analysis of the M RNA segment of TSWV-A, -D, and the type isolate BR-01 revealed multiple differences in the coding and noncoding regions, which prevented identification of the resistance-breaking nucleotide sequences.

Bunyaviridae↗
PubMed1998

Tomato spotted wilt Tospovirus genome reassortment and genome segment-specific adaptation.

A system to associate specific genome segments with viral phenotypes and to study factors influencing genome reassortment was developed for tomato spotted wilt Tospovirus (TSWV). Reassortant isolates were generated by co-inoculating a TSWV isolate, TSWV-D, with TSWV-10 or TSWV-MD. The parental origin of each genome segment in putative reassortant isolates was determined by segment-specific restriction fragment length polymorphisms. The TSWV isolates readily exchanged genome segments in a nonrandom fashion. The S RNA from TSWV-D was dominant over the S RNA from TSWV-10. The intergenic region (IGR) of the S RNA was correlated with competitiveness of this genome segment in reassortant isolates. The less competitive S RNA contained a net increase of 62 nt, including a 33-nt duplication in the IGR. This duplicate sequence was highly conserved among isolates from the southeastern United States and an isolate from Bulgaria. The evidence supports the hypothesis that the IGR of the S RNA with an ambisense coding strategy serves a regulatory function which influences the occurrence of this segment in the viral population. In addition, it was demonstrated that stable parental phenotypes can be mapped to specific genome segments as well as generating novel phenotypes not associated with either parent.

Adaptation, Biological↗
PubMed1992

Comparison of the capsid protein cistron from serologically distinct strains of sweetpotato feathery mottle virus (SPFMV).

Complementary DNA clones corresponding to the 3' terminus of sweetpotato feathery mottle virus (SPFMV) strains RC and C were synthesized and sequenced. An open reading frame followed by a 3' terminal non-coding region of 222 nucleotides and a terminal polyadenylation track was present in clones from both strains. Putative N-terminal capsid protein cleavage sites were identified for both strains 945 nucleotides 5' of the first stop codon. Sequence comparisons of these strains show 98% nucleic acid identity in the last 351 nucleotides of the capsid protein cistron and 100% in the corresponding amino acids. This relatively short homologous sequence element near the C terminus is responsible for the wide spectrum hybridization among SPFMV strains using in vitro transcribed antiviral RNA probes (riboprobes). The sequence similarity in the remaining N terminal 645 nucleotides is only 62% and 65% for their predicted amino acids. A tendency of decreasing nucleotide mismatches in the alignment from 5' to 3' end of both capsid protein cistrons was detected. Although the alignment of the predicted amino acid sequence of the SPFMV-RC capsid protein with those of other potyviruses showed significant homology, hybridization with riboprobes from both the 5' and 3' regions of the capsid protein cistron of SPFMV was virus-specific.

Amino Acid Sequence↗
PubMed1992

The M RNA of impatiens necrotic spot Tospovirus (Bunyaviridae) has an ambisense genomic organization.

The nucleotide sequence of Impatiens necrotic spot virus (INSV) M RNA was determined from cDNA clones. The INSV M RNA was 4972 nucleotides in length with two open reading frames (ORFs) in an ambisense genomic organization. The larger ORF near the 3' end of the viral RNA, coding for a protein with a predicted molecular weight of 124.9 kDa, was in the viral complementary sense and produced the G2 and G1 proteins. A smaller ORF in the viral sense was capable of coding for a 34.1-kDa polypeptide, designated the NSm protein. Two subgenomic RNA species were detected in INSV-infected tissue that corresponded to the predicted sizes (3.3 and 1.0 kb) of the G2-G1 and NSm mRNAs. The ORFs were separated by a 478 nucleotide A-U-rich intergenic region similar to the regions found in other viral RNAs with ambisense ORFs. The intergenic region was predicted to form a stable stem-loop structure (-81.2 kcal/mole). The ambisense genomic organization is characteristic of the S RNA for members of the Phlebovirus, Uukuvirus, and Tospovirus genera in the Bunyaviridae family. This is the first report of an ambisense Bunyaviridae M RNA.

Amino Acid Sequence↗
PubMed1991

Nucleotide sequence of the 3' non-coding region and N gene of the S RNA of a serologically distinct tospovirus.

A tomato spotted wilt-like virus (TSWV-I) is a distinct member of the Tospovirus genus of the Bunyaviridae and is distinguished from the typical TSWV by having a serologically distinct nucleoprotein (N). A cDNA clone extending from the 3' terminus of the viral RNA through the entire N open reading frame (ORF) was sequenced. The TSWV-I N ORF is capable of encoding a polypeptide of 262 amino acids with a predicted Mr of 28.8K. In vitro transcription and translation of the clone produced a protein which comigrated with TSWV-I N and was immunoprecipitated by TSWV-I antibodies. Hybridization analysis of lithium chloride-precipitated RNA from healthy and TSWV-I-infected tissue detected a virus-specific 1.2 kb subgenomic RNA. The TSWV-I S RNA terminal consensus sequence (8 nucleotides) was identical to that of TSWV; the remaining TSWV-I untranslated region showed only 51% identity with that of TSWV. Comparison of the TSWV-I and TSWV N proteins showed 67% identity at the amino acid level. The degree of similarity in the terminal sequence, untranslated region and N ORF is similar to that expected between distinct serogroups within certain genera of the Bunyaviridae.

Amino Acid Sequence↗
PubMed1988

Quantitative structure activity studies of antiarrhythmic properties in a series of lidocaine and procainamide derivatives.

The use- and voltage-dependent depression of the maximum upstroke velocity of the cardiac action potential by a series of lidocaine and procainamide derivatives was studied in guinea pig papillary muscles. The derivatives were chosen to test the effects of the structural and physicochemical differences between lidocaine and procainamide on the kinetics of sodium channel block. Three derivatives were similar to lidocaine with a rapid onset of use-dependent block at fast stimulation rates and short time constants of recovery at normal resting potentials. Seven derivatives were similar to procainamide having slower rates of block development and longer recovery time constants. In order to quantify the differences in sodium channel block the data were analyzed by a model based on the modulated receptor hypothesis. This hypothesis proposes that each of the sodium channel states (rested, open and inactivated) has characteristic association and dissociation rate constants for each sodium channel blocker, drug bound channels do not conduct sodium and have altered inactivation kinetics. This model was solved for the dissociation constants of the drug for the rested and open states, the association and dissociation rate constants for the inactivated channels and the voltage shift of the inactivation kinetics for drug-bound channels. Quantitative structure-activity analysis on the derived parameters revealed that the affinity of the drugs for the open channel state is related to the compounds lipid solubility, the degree of voltage shift was proportional to molecular weight and the dissociation from the inactivated channels was correlated with both the molecular weight and charge.

Action Potentials↗
PubMed1979

Mutagenic action of a series of epoxides.

The mutagenicity of a series of 13 epoxide compounds was studied using a bacterial plate assay system. The histidine-dependent tester strains TA98 (for frameshift mutagens) and TA100 (for base-pair substitution mutagens) of Salmonella typhimurium were used. Mutagenicity was evaluated both with and without the additon of rat liver microsomal extract. Dieldrin, diglycidyl ether of bis phenol A and 3 of its homologues were not mutagenic. Allyl glycidyl ether, n-butyl glycidyl ether, vinly cyclohexene diepoxide, glycidol, glycidal-dehyde, diglycidyl ether, diepoxybutane and diglycidyl ether of substituted glycerine were mutagenic in the TA100 strain, causing reversion of the bacteria to histidine independence. Dose-reponse curves of the mutagenicity of the latter 4 compounds were obtained. On a molar basis, glycidaldehyde was about 20-50 times more potent in producing mutation that were the other 3 epoxides in the dose-response test. In general, the mutagenicity of the epoxides was not enhanced or diminished by the addition of microsomal extract.

Drug Evaluation, Preclinical↗