Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 48
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Gen Virol ; 101(1): 105-111, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31769392

RESUMO

A novel picorna-like virus, provisionally named Aphis glycines virus 1 (ApGlV1) was discovered by high-throughput sequencing of soybean total RNAs and detected in suction trap-collected Aphis glycines. The ApGlV1 genome contains two large ORFs organized similar to those of dicipiviruses in the Picornaviridae where ORFs 1 and 2 encode structural and nonstructural proteins, respectively. Both ORFs are preceded by internal ribosome entry site (IRES) elements. The 5' IRES was more active in dual luciferase activity assays than the IRES in the intergenic region. The ApGlV1 genome was predicted to encode a serine protease instead of a cysteine protease and showed very low aa sequence identities to recognized members of the Picornavirales. In phylogenetic analyses based on capsid protein and RNA-dependent RNA polymerase sequences, ApGlV1 consistently clustered with a group of unclassified bicistronic picorna-like viruses discovered from arthropods and plants that may represent a novel family in the order Picornavirales.


Assuntos
Sítios Internos de Entrada Ribossomal/genética , Picornaviridae/genética , Vírus não Classificados/genética , Genoma Viral/genética , Fases de Leitura Aberta/genética , Vírus de RNA/genética , RNA Viral/genética , Proteínas Virais/genética
2.
Plant Dis ; 103(8): 1876-1883, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31161932

RESUMO

Soybean cyst nematode (SCN; Heterodera glycines Ichinohe) is a major pathogen of soybean [Glycine max (L.) Merr.] in the United States. The spatial distribution of SCN in 10 naturally infested research sites in North Dakota was examined between 2006 and 2009. Egg densities were measured in plots and expressed as arithmetic means or grouped into classes using two categorical scales based on the effect of SCN on yield. Data were used to determine spatial distribution, egg cluster sizes, minimum plot sizes, and replications in field experiments. SCN populations varied among plots from undetected to 25,800 eggs/100 cm3 of soil, and differences between adjacent plots were as high as sixfold. Mean to median ratios and Lloyd's index of patchiness suggested an aggregated distribution in nine of the 10 sites. SCN cluster sizes varied in five of the 10 sites and optimum plot size over all sites varied depending on calculation methods. The minimum number of replications needed to detect specific differences among plots varied between field sites. Grouping data into either of the two categories generally increased the ability to detect differences between plots. The spatial distribution of SCN can be a critical factor affecting design and outcomes of field experiments.


Assuntos
Glycine max , Doenças das Plantas , Tylenchoidea , Animais , North Dakota , Doenças das Plantas/parasitologia , Doenças das Plantas/estatística & dados numéricos , Glycine max/parasitologia , Tylenchoidea/fisiologia
3.
PLoS One ; 14(2): e0212140, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30730982

RESUMO

Common bean (Phaseolus vulgaris L.) is an important high protein crop grown worldwide. North Dakota and Minnesota are the largest producers of common beans in the USA, but crop production is threatened by soybean cyst nematode (SCN; Heterodera glycines Ichinohe) because most current cultivars are susceptible. Greenhouse screening data using SCN HG type 0 from 317 plant introductions (PI's) from the USDA core collection was used to conduct a genome wide association study (GWAS). These lines were divided into two subpopulations based on principal component analysis (Middle American vs. Andean). Phenotypic results based on the female index showed that accessions could be classified as highly resistant (21% and 27%), moderately resistant (51% and 48%), moderately susceptible (27% and 22%) and highly susceptible (1% and 3%) for Middle American and Andean gene pools, respectively. Mixed models with two principal components (PCs) and kinship matrix for Middle American genotypes and Andean genotypes were used in the GWAS analysis using 3,985 and 4,811 single nucleotide polymorphic (SNP) markers, respectively which were evenly distributed across all 11 chromosomes. Significant peaks on Pv07, and Pv11 in Middle American and on Pv07, Pv08, Pv09 and Pv11 in Andean group were found to be associated with SCN resistance. Homologs of soybean rhg1, a locus which confers resistance to SCN in soybean, were identified on chromosomes Pv01 and Pv08 in the Middle American and Andean gene pools, respectively. These genomic regions may be the key to develop SCN-resistant common bean cultivars.


Assuntos
Resistência à Doença/genética , Genoma de Planta/genética , Estudo de Associação Genômica Ampla , Phaseolus/genética , Phaseolus/imunologia , Doenças das Plantas/imunologia , Tylenchoidea/fisiologia , Animais , Fenótipo , Polimorfismo de Nucleotídeo Único
4.
Vet J ; 232: 40-45, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29428090

RESUMO

The aim of this prospective study was to investigate possible endocrine components to foal rejection behaviour in post-partum Arabian mares. Arabian mares were divided into two groups based on their maternal behaviour: (1) mares with normal post-parturient behaviour (8 mares); and (2) mares that demonstrated foal-rejecting behaviour post-partum (15 mares). Most mares were visited and sampled twice, in the first and third days post-partum. Serum samples were used for measurement of progesterone, oestradiol and prolactin concentrations. There were no statistically significant differences in oestradiol, progesterone or prolactin concentrations between the groups. In the rejecting mares, there was a statistically significant decrease in the progesterone (mean±standard deviation, SD, 3.14±6.2ng/dL on day 1 and 0.49±0.18ng/dL on day 3) and prolactin (mean±SD 216.2±325.4ng/mL on day 1 and 145.2±311.4ng/mL on day 3) concentrations between days 1 and 3, while the oestradiol concentration did not change significantly. In the non-rejecting mares, progesterone concentrations decreased significantly (mean±SD 0.8±0.23ng/dL on day 1 and 0.43±0.22 on day 3) while the oestradiol and prolactin concentrations did not change significantly. The oestradiol to progesterone ratio was significantly higher in non-rejecting mares on day 1 (mean±SD 114.8±140.2 on day 1 and 143.4±72.6 on day 3) and this ratio increased significantly from days 1 to 3 in the rejecting mares (mean±SD 47.3±21.1 on day 1 and 122.1±123.7 on day 3).


Assuntos
Estradiol/sangue , Cavalos/sangue , Comportamento Materno/fisiologia , Período Pós-Parto/sangue , Progesterona/sangue , Prolactina/sangue , Animais , Feminino , Estudos Prospectivos
5.
Plant Dis ; 102(2): 327-333, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30673525

RESUMO

Fusarium solani species complex (FSSC) 11 is the primary phylogenetic species of FSSC causing root rot in soybean in the north-central United States. A polymerase chain reaction (PCR)-based assay was developed to identify and differentiate FSSC 11 from the less aggressive FSSC 5 and other Fusarium and Pythium spp. associated with soybean roots. The primer set FSSC11-F and FSSC11-R designed from the RNA polymerase second largest subunit gene yielded the expected amplicon of about 900 bp with DNA from all 22 FSSC 11 isolates tested in PCR. However, it did not produce an amplicon with DNA from 29 isolates of FSSC 5, seven other Fusarium spp., three Pythium spp., and soybean tested in PCR. Furthermore, the primer set successfully detected FSSC 11 from a DNA mixture containing the DNA of FSSC 11, FSSC 5, other Fusarium spp., and soybean. The primer set also detected FSSC 11 from both soil and soybean roots. Additionally, the prevalence of FSSC 11 in soybean roots was determined in five fields in North Dakota by both a culture-independent PCR approach with FSSC11-F and FSSC11-R and a culture-dependent approach. Results from both the culture-dependent and culture-independent approaches with FSSC11-F and FSSC11-R were consistent and revealed the presence of the FSSC 11 in three of five fields sampled.


Assuntos
Fusarium/isolamento & purificação , Glycine max/microbiologia , Doenças das Plantas/microbiologia , Reação em Cadeia da Polimerase/métodos , Primers do DNA/análise , Raízes de Plantas/microbiologia , Sensibilidade e Especificidade , Microbiologia do Solo
6.
Microb Ecol ; 74(3): 550-560, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28386770

RESUMO

Associations between soil properties and Pythium groups on soybean roots were investigated in 83 commercial soybean fields in North Dakota. A data set containing 2877 isolates of Pythium which included 26 known spp. and 1 unknown spp. and 13 soil properties from each field were analyzed. A Pearson correlation analysis was performed with all soil properties to observe any significant correlation between properties. Hierarchical clustering, indicator spp., and multi-response permutation procedures were used to identify groups of Pythium. Logistic regression analysis using stepwise selection was employed to calculate probability models for presence of groups based on soil properties. Three major Pythium groups were identified and three soil properties were associated with these groups. Group 1, characterized by P. ultimum, was associated with zinc levels; as zinc increased, the probability of group 1 being present increased (α = 0.05). Pythium group 2, characterized by Pythium kashmirense and an unknown Pythium sp., was associated with cation exchange capacity (CEC) (α < 0.05); as CEC increased, these spp. increased. Group 3, characterized by Pythium heterothallicum and Pythium irregulare, were associated with CEC and calcium carbonate exchange (CCE); as CCE increased and CEC decreased, these spp. increased (α = 0.05). The regression models may have value in predicting pathogenic Pythium spp. in soybean fields in North Dakota and adjacent states.


Assuntos
Glycine max/microbiologia , Pythium/fisiologia , Microbiologia do Solo , Solo/química , Modelos Biológicos , North Dakota , Raízes de Plantas/microbiologia , Probabilidade
7.
Transbound Emerg Dis ; 64(2): 593-602, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26392206

RESUMO

It is claimed that the distribution of Culicoides-borne viruses is highly influenced by climate. Equine encephalosis virus (EEV) is a Culicoides-borne orbivirus which affects horses and was recently found to be endemic in Israel. To test whether climate is a crucial factor in the geographical distribution of EEV, we collected blood samples from horses in Israel during the years 2002, 2007 and 2010 and tested them for the abundance of antibodies to EEV. Samples were also collected in 2011 from horses that were seronegative to the virus in 2010, to determine the rate of infection with EEV. It was found that seroprevalence fluctuated between the years and that in each year it was highest in a different climatic region. Interestingly, analysis of infection rate at the different farms showed a negative association with seroprevalence at prior observations. In addition, analysis of precipitation preceding the outbreak of EEV which occurred during 2008 revealed that an extremely dry period existed several months prior to the febrile outbreak with the average precipitation of spring 2008 being significantly lower than the average spring precipitation of the years 1997-2009. It is therefore conjectured that exposure to EEV is not climate specific. Rather, it is highly influenced by herd immunity and weather fluctuations which might change annually. This finding may have important implications for the prediction of the abundance of Culicoides-borne viruses in endemic regions.


Assuntos
Doenças dos Cavalos/transmissão , Orbivirus , Infecções por Reoviridae/transmissão , Animais , Clima , Surtos de Doenças/veterinária , Doenças dos Cavalos/epidemiologia , Doenças dos Cavalos/virologia , Cavalos , Imunidade Coletiva , Israel/epidemiologia , Orbivirus/isolamento & purificação , Infecções por Reoviridae/epidemiologia , Infecções por Reoviridae/veterinária , Tempo (Meteorologia)
8.
Arch Virol ; 162(4): 1089-1092, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27921175

RESUMO

The complete nucleotide sequence of a new soybean-infecting member of the genus Nepovirus (provisionally named "soybean latent spherical virus" [SLSV]) was identified by high-throughput sequencing of RNAs from soybean leaf samples from North Dakota, USA. The sequences of RNAs 1 (8,190 nt) and 2 (5,788 nt) were completed by rapid amplification of cDNA ends. Each contained a single long open reading frame and a 3' nontranslated region of greater than 1,500 nt. The predicted amino acid sequences of the two ORFs were most closely related to nepoviruses in subgroup C. Full-length cDNAs of RNAs 1 and 2 were cloned and used to inoculate soybean plants, which did not display obvious symptoms. These results suggest that SLSV represents a new species in the genus Nepovirus.


Assuntos
Glycine max/virologia , Nepovirus/genética , Nepovirus/isolamento & purificação , Doenças das Plantas/virologia , Sequência de Aminoácidos , Sequência de Bases , Genoma Viral , Sequenciamento de Nucleotídeos em Larga Escala , Dados de Sequência Molecular , Nepovirus/classificação , Nepovirus/fisiologia , Fases de Leitura Aberta , Filogenia , RNA Viral/genética , Alinhamento de Sequência , Proteínas Virais/química , Proteínas Virais/genética
9.
Phytopathology ; 107(3): 293-304, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27841963

RESUMO

Soybean (Glycine max (L.) Merr.) is produced across a vast swath of North America, with the greatest concentration in the Midwest. Root rot diseases and damping-off are a major concern for production, and the primary causal agents include oomycetes and fungi. In this study, we focused on examination of oomycete species distribution in this soybean production system and how environmental and soil (edaphic) factors correlate with oomycete community composition at early plant growth stages. Using a culture-based approach, 3,418 oomycete isolates were collected from 11 major soybean-producing states and most were identified to genus and species using the internal transcribed spacer region of the ribosomal DNA. Pythium was the predominant genus isolated and investigated in this study. An ecology approach was taken to understand the diversity and distribution of oomycete species across geographical locations of soybean production. Metadata associated with field sample locations were collected using geographical information systems. Operational taxonomic units (OTU) were used in this study to investigate diversity by location, with OTU being defined as isolate sequences with 97% identity to one another. The mean number of OTU ranged from 2.5 to 14 per field at the state level. Most OTU in this study, classified as Pythium clades, were present in each field in every state; however, major differences were observed in the relative abundance of each clade, which resulted in clustering of states in close proximity. Because there was similar community composition (presence or absence) but differences in OTU abundance by state, the ordination analysis did not show strong patterns of aggregation. Incorporation of 37 environmental and edaphic factors using vector-fitting and Mantel tests identified 15 factors that correlate with the community composition in this survey. Further investigation using redundancy analysis identified latitude, longitude, precipitation, and temperature as factors that contribute to the variability observed in community composition. Soil parameters such as clay content and electrical conductivity also affected distribution of oomycete species. The present study suggests that oomycete species composition across geographical locations of soybean production is affected by a combination of environmental and edaphic conditions. This knowledge provides the basis to understand the ecology and distribution of oomycete species, especially those able to cause diseases in soybean, providing cues to develop management strategies.


Assuntos
Variação Genética , Glycine max/parasitologia , Oomicetos/isolamento & purificação , Doenças das Plantas/parasitologia , Aphanomyces/classificação , Aphanomyces/isolamento & purificação , Aphanomyces/patogenicidade , Ecologia , Meio Ambiente , Sequenciamento de Nucleotídeos em Larga Escala , Oomicetos/classificação , Oomicetos/patogenicidade , Phytophthora/classificação , Phytophthora/isolamento & purificação , Phytophthora/patogenicidade , Doenças das Plantas/prevenção & controle , Raízes de Plantas/parasitologia , Pythium/classificação , Pythium/isolamento & purificação , Pythium/patogenicidade , Plântula/parasitologia , Sementes/parasitologia , Análise de Sequência de DNA , Virulência
10.
Phytopathology ; 107(3): 280-292, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27801078

RESUMO

Oomycete pathogens are commonly associated with soybean root rot and have been estimated to reduce soybean yields in the United States by 1.5 million tons on an annual basis. Limited information exists regarding the frequency and diversity of oomycete species across the major soybean-producing regions in North America. A survey was conducted across 11 major soybean-producing states in the United States and the province of Ontario, Canada. In 2011, 2,378 oomycete cultures were isolated from soybean seedling roots on a semiselective medium (CMA-PARPB) and were identified by sequencing of the internal transcribed spacer region of rDNA. Sequence results distinguished a total of 51 Pythium spp., three Phytophthora spp., three Phytopythium spp., and one Aphanomyces sp. in 2011, with Pythium sylvaticum (16%) and P. oopapillum (13%) being the most prevalent. In 2012, the survey was repeated, but, due to drought conditions across the sampling area, fewer total isolates (n = 1,038) were collected. Additionally, in 2012, a second semiselective medium (V8-RPBH) was included, which increased the Phytophthora spp. isolated from 0.7 to 7% of the total isolates. In 2012, 54 Pythium spp., seven Phytophthora spp., six Phytopythium spp., and one Pythiogeton sp. were recovered, with P. sylvaticum (14%) and P. heterothallicum (12%) being recovered most frequently. Pathogenicity and virulence were evaluated with representative isolates of each of the 84 species on soybean cv. Sloan. A seed-rot assay identified 13 and 11 pathogenic species, respectively, at 13 and 20°C. A seedling-root assay conducted at 20°C identified 43 species as pathogenic, having a significantly detrimental effect on the seedling roots as compared with the noninoculated control. A total of 15 species were pathogenic in both the seed and seedling assays. This study provides a comprehensive characterization of oomycete species present in soybean seedling roots in the major production areas in the United States and Ontario, Canada and provides a basis for disease management and breeding programs.


Assuntos
Glycine max/parasitologia , Oomicetos/isolamento & purificação , Doenças das Plantas/parasitologia , Aphanomyces/classificação , Aphanomyces/isolamento & purificação , Aphanomyces/patogenicidade , Geografia , Oomicetos/classificação , Oomicetos/patogenicidade , Filogenia , Phytophthora/classificação , Phytophthora/isolamento & purificação , Phytophthora/patogenicidade , Doenças das Plantas/prevenção & controle , Raízes de Plantas/parasitologia , Pythium/classificação , Pythium/isolamento & purificação , Pythium/patogenicidade , Plântula/parasitologia , Sementes/parasitologia , Virulência
11.
PLoS One ; 11(7): e0159338, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27441552

RESUMO

Soybean cyst nematode (SCN; Heterodera glycines Ichinohe) reproduces on the roots of common bean (Phaseolus vulgaris L.) and can cause reductions in plant growth and seed yield. The molecular changes in common bean roots caused by SCN infection are unknown. Identification of genetic factors associated with SCN resistance could help in development of improved bean varieties with high SCN resistance. Gene expression profiling was conducted on common bean roots infected by SCN HG type 0 using next generation RNA sequencing technology. Two pinto bean genotypes, PI533561 and GTS-900, resistant and susceptible to SCN infection, respectively, were used as RNA sources eight days post inoculation. Total reads generated ranged between ~ 3.2 and 5.7 million per library and were mapped to the common bean reference genome. Approximately 70-90% of filtered RNA-seq reads uniquely mapped to the reference genome. In the inoculated roots of resistant genotype PI533561, a total of 353 genes were differentially expressed with 154 up-regulated genes and 199 down-regulated genes when compared to the transcriptome of non- inoculated roots. On the other hand, 990 genes were differentially expressed in SCN-inoculated roots of susceptible genotype GTS-900 with 406 up-regulated and 584 down-regulated genes when compared to non-inoculated roots. Genes encoding nucleotide-binding site leucine-rich repeat resistance (NLR) proteins, WRKY transcription factors, pathogenesis-related (PR) proteins and heat shock proteins involved in diverse biological processes were differentially expressed in both resistant and susceptible genotypes. Overall, suppression of the photosystem was observed in both the responses. Furthermore, RNA-seq results were validated through quantitative real time PCR. This is the first report describing genes/transcripts involved in SCN-common bean interaction and the results will have important implications for further characterization of SCN resistance genes in common bean.


Assuntos
Resistência à Doença/genética , Perfilação da Expressão Gênica/métodos , Glycine max/parasitologia , Phaseolus/genética , Phaseolus/parasitologia , Doenças das Plantas/genética , Tylenchoidea/fisiologia , Animais , Regulação da Expressão Gênica de Plantas , Genoma de Planta , Genótipo , Infecções por Nematoides/genética , Doenças das Plantas/imunologia , Reação em Cadeia da Polimerase em Tempo Real , Reprodutibilidade dos Testes , Análise de Sequência de RNA , Fatores de Transcrição/metabolismo , Transcriptoma/genética
12.
J Virol ; 90(15): 6846-6863, 2016 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-27194764

RESUMO

UNLABELLED: Mycoviruses can have a marked effect on natural fungal communities and influence plant health and productivity. However, a comprehensive picture of mycoviral diversity is still lacking. To characterize the viromes of five widely dispersed plant-pathogenic fungi, Colletotrichum truncatum, Macrophomina phaseolina, Diaporthe longicolla, Rhizoctonia solani, and Sclerotinia sclerotiorum, a high-throughput sequencing-based metatranscriptomic approach was used to detect viral sequences. Total RNA and double-stranded RNA (dsRNA) from mycelia and RNA from samples enriched for virus particles were sequenced. Sequence data were assembled de novo, and contigs with predicted amino acid sequence similarities to viruses in the nonredundant protein database were selected. The analysis identified 72 partial or complete genome segments representing 66 previously undescribed mycoviruses. Using primers specific for each viral contig, at least one fungal isolate was identified that contained each virus. The novel mycoviruses showed affinity with 15 distinct lineages: Barnaviridae, Benyviridae, Chrysoviridae, Endornaviridae, Fusariviridae, Hypoviridae, Mononegavirales, Narnaviridae, Ophioviridae, Ourmiavirus, Partitiviridae, Tombusviridae, Totiviridae, Tymoviridae, and Virgaviridae More than half of the viral sequences were predicted to be members of the Mitovirus genus in the family Narnaviridae, which replicate within mitochondria. Five viral sequences showed strong affinity with three families (Benyviridae, Ophioviridae, and Virgaviridae) that previously contained no mycovirus species. The genomic information provides insight into the diversity and taxonomy of mycoviruses and coevolution of mycoviruses and their fungal hosts. IMPORTANCE: Plant-pathogenic fungi reduce crop yields, which affects food security worldwide. Plant host resistance is considered a sustainable disease management option but may often be incomplete or lacking for some crops to certain fungal pathogens or strains. In addition, the rising issues of fungicide resistance demand alternative strategies to reduce the negative impacts of fungal pathogens. Those fungus-infecting viruses (mycoviruses) that attenuate fungal virulence may be welcome additions for mitigation of plant diseases. By high-throughput sequencing of the RNAs from 275 isolates of five fungal plant pathogens, 66 previously undescribed mycoviruses were identified. In addition to identifying new potential biological control agents, these results expand the grand view of the diversity of mycoviruses and provide possible insights into the importance of intracellular and extracellular transmission in fungus-virus coevolution.


Assuntos
Ascomicetos/virologia , Micovírus/classificação , Micovírus/genética , Genoma Viral , Metagenômica , Doenças das Plantas/virologia , Plantas/virologia , Transcriptoma , Micovírus/isolamento & purificação , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Micélio/virologia , Filogenia , RNA Viral/genética
13.
PLoS One ; 10(9): e0139188, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26417989

RESUMO

Sclerotinia sclerotiorum is an important pathogen of numerous crops in the North Central region of the United States. The objective of this study was to examine the genetic diversity of 145 isolates of the pathogen from multiple hosts in the region. Mycelial compatibility groups (MCG) and microsatellite haplotypes were determined and analyzed for standard estimates of population genetic diversity and the importance of host and distance for genetic variation was examined. MCG tests indicated there were 49 different MCGs in the population and 52 unique microsatellite haplotypes were identified. There was an association between MCG and haplotype such that isolates belonging to the same MCG either shared identical haplotypes or differed at no more than 2 of the 12 polymorphic loci. For the majority of isolates, there was a one-to-one correspondence between MCG and haplotype. Eleven MCGs shared haplotypes. A single haplotype was found to be prevalent throughout the region. The majority of genetic variation in the isolate collection was found within rather than among host crops, suggesting little genetic divergence of S. sclerotiorum among hosts. There was only weak evidence of isolation by distance. Pairwise population comparisons among isolates from canola, dry bean, soybean and sunflower suggested that gene flow between host-populations is more common for some crops than others. Analysis of linkage disequilibrium in the isolates from the four major crops indicated primarily clonal reproduction, but also evidence of genetic recombination for isolates from canola and sunflower. Accordingly, genetic diversity was highest for populations from canola and sunflower. Distribution of microsatellite haplotypes across the study region strongly suggest that specific haplotypes of S. sclerotiorum are often found on multiple crops, movement of individual haplotypes among crops is common and host identity is not a barrier to gene flow for S. sclerotiorum in the north central United States.


Assuntos
Ascomicetos/genética , Produtos Agrícolas/microbiologia , Variação Genética/genética , Repetições de Microssatélites/genética , Doenças das Plantas/microbiologia , Ascomicetos/classificação , Ascomicetos/isolamento & purificação , Brassica napus/microbiologia , DNA Fúngico/genética , Deriva Genética , Geografia , Haplótipos/genética , Helianthus/microbiologia , Desequilíbrio de Ligação/genética , Análise de Componente Principal , Glycine max/microbiologia , Estados Unidos
14.
J Virol ; 89(9): 5060-71, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25694604

RESUMO

UNLABELLED: A recombinant strain of Sclerotinia sclerotiorum hypovirus 2 (SsHV2) was identified from a North American Sclerotinia sclerotiorum isolate (328) from lettuce (Lactuca sativa L.) by high-throughput sequencing of total RNA. The 5'- and 3'-terminal regions of the genome were determined by rapid amplification of cDNA ends. The assembled nucleotide sequence was up to 92% identical to two recently reported SsHV2 strains but contained a deletion near its 5' terminus of more than 1.2 kb relative to the other SsHV2 strains and an insertion of 524 nucleotides (nt) that was distantly related to Valsa ceratosperma hypovirus 1. This suggests that the new isolate is a heterologous recombinant of SsHV2 with a yet-uncharacterized hypovirus. We named the new strain Sclerotinia sclerotiorum hypovirus 2 Lactuca (SsHV2L) and deposited the sequence in GenBank with accession number KF898354. Sclerotinia sclerotiorum isolate 328 was coinfected with a strain of Sclerotinia sclerotiorum endornavirus 1 and was debilitated compared to cultures of the same isolate that had been cured of virus infection by cycloheximide treatment and hyphal tipping. To determine whether SsHV2L alone could induce hypovirulence in S. sclerotiorum, a full-length cDNA of the 14,538-nt viral genome was cloned. Transcripts corresponding to the viral RNA were synthesized in vitro and transfected into a virus-free isolate of S. sclerotiorum, DK3. Isolate DK3 transfected with SsHV2L was hypovirulent on soybean and lettuce and exhibited delayed maturation of sclerotia relative to virus-free DK3, completing Koch's postulates for the association of hypovirulence with SsHV2L. IMPORTANCE: A cosmopolitan fungus, Sclerotinia sclerotiorum infects more than 400 plant species and causes a plant disease known as white mold that produces significant yield losses in major crops annually. Mycoviruses have been used successfully to reduce losses caused by fungal plant pathogens, but definitive relationships between hypovirus infections and hypovirulence in S. sclerotiorum were lacking. By establishing a cause-and-effect relationship between Sclerotinia sclerotiorum hypovirus Lactuca (SsHV2L) infection and the reduction in host virulence, we showed direct evidence that hypoviruses have the potential to reduce the severity of white mold disease. In addition to intraspecific recombination, this study showed that recent interspecific recombination is an important factor shaping viral genomes. The construction of an infectious clone of SsHV2L allows future exploration of the interactions between SsHV2L and S. sclerotiorum, a widespread fungal pathogen of plants.


Assuntos
Ascomicetos/virologia , Transfecção , Vírus/genética , Ascomicetos/genética , Ascomicetos/crescimento & desenvolvimento , Lactuca/microbiologia , Lactuca/virologia , Dados de Sequência Molecular , Filogenia , RNA Viral/genética , Análise de Sequência de DNA , Homologia de Sequência , Glycine max/microbiologia , Virulência , Vírus/classificação , Vírus/isolamento & purificação
15.
Plant Dis ; 99(1): 31-38, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30699738

RESUMO

The oomycete Pythium comprises one of the most important groups of seedling pathogens affecting soybean. There has been limited research on Pythium spp. pathogenic on soybean in the northern Great Plains. The objectives of this research were to isolate and identify Pythium spp. infecting soybean in North Dakota and to test their pathogenicity. Identification of Pythium spp. was achieved using molecular techniques and morphological features. A total of 26 known Pythium spp. and three unknown species were recovered from soybean seedling roots collected from 125 fields between 2011 and 2012. In 2011, the three most abundant species isolated were P. ultimum, Pythium sp. (unknown; GenBank HQ643777.1), and P. heterothallicum, representing 21, 16, and 12% of 2,675 isolates, respectively. More species and isolates were obtained in 2011, a wet and cool year, compared with 2012, which was dry and warm. The majority of Pythium spp. caused pre-emergence damping-off on soybean with less than 50% emergence in a 2-week test using infested soil at 23°C. In contrast, in the presence of P. orthogonon, P. nunn, or P. rostratifingens there was approximately 80% or greater emergence and most plants survived for several weeks, although lesions were observed on roots. Mortierella spp., a zygomycete, was commonly isolated along with Pythium spp. in 2012, but not in 2011. This is the first report of P. kashmirense, P. minus, P. periilum, P. rostratifingens, P. terrestris, P. viniferum, and P. violae as pathogens of soybean seedlings. In addition, this is the first report of P. kashmirense, P. viniferum, and P. terrestris in the United States.

17.
Equine Vet J Suppl ; (43): 111-4, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23447889

RESUMO

REASONS FOR PERFORMING STUDY: There is a consensus in the veterinary literature that Parascaris equorum (ascarid) impaction carries a poor prognosis. Hence surgery is often delayed and foals are often subjected to euthanasia after diagnosis of ascarid impaction is established. Our clinical impression was that ascarid impaction carries a better prognosis than previously reported. OBJECTIVES: Our expectation was that manually evacuating the impaction into the caecum, thus refraining from opening the small intestine, would improve the prognosis for survival of horses with ascarid impaction. The aim of this study was to examine medical records of horses treated surgically for ascarid impaction, record their clinical findings and evaluate the association of outcome with the method of relieving the impaction. METHODS: The medical records of all horses presented to our hospital between October 2002 and December 2011 that underwent exploratory celiotomy for ascarid impaction were reviewed. Information retrieved from the medical record included surgical findings, surgical technique, complications, short- and long-term survival. The association between categorical variables was assessed using the Fisher's exact test. A P value < 0.05 was considered statistically significant. RESULTS: Fifteen horses fulfilled the inclusion criteria. Eighty percent of horses (12/15) survived to discharge and 60% (6/10) survived for at least one year. Five horses are doing well but are still in convalescence. Horses that underwent small intestinal enterotomy or resection and anastomosis (n = 5) were less likely to survive to discharge (P = 0.022). CONCLUSIONS: In our study, manual evacuation of ascarid impaction into the caecum, while refraining from opening the small intestine resulted in significantly improved survival in horses with ascarid impaction. POTENTIAL RELEVANCE: Refraining from opening the small intestine may be the key to improving surgical outcome in horses with ascarid impaction.


Assuntos
Infecções por Ascaridida/veterinária , Ascaridoidea , Doenças dos Cavalos/parasitologia , Obstrução Intestinal/veterinária , Intestino Delgado/parasitologia , Animais , Infecções por Ascaridida/patologia , Infecções por Ascaridida/cirurgia , Doenças dos Cavalos/patologia , Doenças dos Cavalos/cirurgia , Cavalos , Obstrução Intestinal/parasitologia , Obstrução Intestinal/patologia , Obstrução Intestinal/cirurgia , Intestino Delgado/patologia , Intestino Delgado/cirurgia
18.
Plant Dis ; 95(10): 1239-1243, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30731694

RESUMO

Phaseolus vulgaris is a host of soybean cyst nematode (SCN; Heterodera glycines), a pathogen recently introduced into the major dry bean production area of North Dakota and northern Minnesota. The nematode reproduces less on most bean classes compared with soybean but can reduce plant growth and seed yield. An important question is the following: will SCN adapt to dry bean and, over time, increase in ability to reproduce on roots? To answer this question, the following experiments were conducted with cultivars from three bean classes. The cultivars 'Premiere' and 'Cirrus' (navy), 'Buster' and 'Othello' (pinto), and 'Eclipse' and 'Jaguar' (black) were grown in "Cone-tainers" in sand in plastic pots immersed in a water bath at 27°C in the greenhouse. Seedlings were inoculated with 2,000 eggs per plant of SCN HG 0 and cysts were harvested and counted after 40 days. The eggs were immediately extracted from those cysts and seedlings were inoculated again and grown for 40 days using the same methods. Soybean 'Lee 74' was used as a control. A female index (number of cysts produced on the test plant divided by the number of cysts produced on Lee 74) was calculated for each bean cultivar after each period of 40 days. This procedure was repeated until eight generations of eggs were completed and then the experiment was repeated. There was no significant (P ≤ 0.05) change over time in the female index on the six bean cultivars. Therefore, there was no evidence that SCN HG 0 was increasing reproduction on dry bean cultivars during two 11-month periods of continual reproduction of HG 0 on roots.

19.
Clin Pharmacol Ther ; 87(4): 393-5, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20305671

RESUMO

DNATwist is a Web-based learning tool (available at http://www.dnatwist.org) that explains pharmacogenomics concepts to middle- and high-school students. Its features include (i) a focus on drug responses of interest to teenagers (e.g., alcohol intolerance), (ii) reusable graphical interfaces that reduce extension costs, and (iii) explanations of molecular and cellular drug responses. In testing, students found the tool and topic understandable and engaging. The tool is being modified for use at the Tech Museum of Innovation in California.


Assuntos
Internet , Farmacogenética/educação , Ensino , Adolescente , Consumo de Bebidas Alcoólicas/efeitos adversos , California , Humanos , Estudantes , Ensino/economia
20.
Neurology ; 74(6): 494-501, 2010 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-20142616

RESUMO

OBJECTIVE: To analyze the risk factors, presentation, etiologies, and outcomes of adult cancer patients with intracranial hemorrhage (IH). METHODS: We analyzed 208 patients retrospectively with the diagnosis of IH from the Memorial Sloan-Kettering neurology database from January 2000 through December 2007. Charts were examined for clinical and radiographic data. Survival was calculated using the Kaplan-Meier method. Survival between groups was compared via the log-rank test. Logistic regression models were used to assess for prognostic indicators of 30- and 90-day mortality. RESULTS: There were 181 intracerebral and 46 subarachnoid hemorrhages. Sixty-eight percent of patients had solid tumors, 16% had primary brain tumors, and 16% had hematopoietic tumors. Hemiparesis and headache were the most common symptoms. Intratumoral hemorrhage (61%) and coagulopathy (46%) accounted for the majority of hemorrhages, whereas hypertension (5%) was rare. Median survival was 3 months (95% confidence interval [CI] 2-4), and 30-day mortality was 31%. However, nearly one-half of patients were completely or partially independent at the time of discharge. Patients with primary brain tumors had the longest median survival (5.9 months, 95% CI 2.9-11.8, p = 0.05). Independent predictors of 30-day mortality were not having a primary brain tumor, impaired consciousness, multiple foci of hemorrhage, hydrocephalus, no ventriculostomy, and treatment of increased intracranial pressure. CONCLUSIONS: Intracranial hemorrhage in patients with cancer is often due to unique mechanisms. Prognosis is poor, but comparable to intracranial hemorrhage in the general population. Aggressive care is recommended despite high mortality, because many patients have good functional outcomes.


Assuntos
Hemorragia Cerebral/complicações , Neoplasias/complicações , Hemorragia Subaracnóidea/complicações , Adulto , Idoso , Idoso de 80 Anos ou mais , Hemorragia Cerebral/mortalidade , Hemorragia Cerebral/terapia , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Neoplasias/mortalidade , Neoplasias/terapia , Estudos Retrospectivos , Fatores de Risco , Esteroides/uso terapêutico , Hemorragia Subaracnóidea/mortalidade , Hemorragia Subaracnóidea/terapia , Resultado do Tratamento , Ventriculostomia , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...