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1.
Monogr Soc Res Child Dev ; 81(4): 7-29, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27943323

RESUMO

Executive control (EC) is a central construct in developmental science, although measurement limitations have hindered understanding of its nature and development in young children, relation to social risk, and prediction of important outcomes. Disentangling EC from the foundational cognitive abilities it regulates and that are inherently required for successful executive task completion (e.g., language, visual/spatial perception, and motor abilities) is particularly challenging at preschool age, when these foundational abilities are still developing and consequently differ substantially among children. A novel latent bifactor modeling approach delineated respective EC and foundational cognitive abilities components that undergird executive task performance in a socio demographically stratified sample of 388 preschoolers in a longitudinal, cohort-sequential study. The bifactor model revealed a developmental shift, where both EC and foundational cognitive abilities contributed uniquely to executive task performance at ages 4.5 and 5.25 years, but were not separable at ages 3 and 3.75. Contrary to the view that EC is vulnerable to socio-familial risk, the contributions of household financial and learning resources to executive task performance were not specific to EC but were via their relation to foundational cognitive abilities. EC, though, showed a unique, discriminant relation with hyperactive symptoms late in the preschool period, whereas foundational cognitive abilities did not predict specific dimensions of dysregulated behavior. These findings form the basis for a new, integrated approach to the measurement and conceptualization of EC, which includes dual consideration of the contributions of EC and foundational cognitive abilities to executive task performance, particularly in the developmental context of preschool.


Assuntos
Desenvolvimento Infantil , Função Executiva , Psicologia da Criança , Pré-Escolar , Humanos , Modelos Psicológicos , Testes Neuropsicológicos
2.
J Econ Entomol ; 107(2): 538-45, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24772532

RESUMO

Myzus persicae (Sulzer) is an efficient vector of potyviruses in sweet potato, Ipomoea batatas (L.). These potyviruses also infect members of the morning glory family Ipomoea cordatotriloba Dennstedt and Ipomoea hederacea Jacqin commonly found within or around sweet potato fields. Infection of sweet potato with potyviruses increases the intrinsic rate of increase of M. persicae. Thus, from the epidemiological stand point, virus infection can modify vector population dynamics, and therefore increase virus spread. To better understand this, stylet penetration behaviors of M. persicae on virus infected and noninfected sweet potato cvs. 'Beauregard' and 'Evangeline', as well as morning glory plants I. cordatotriloba and I. hederacea were monitored. Stylet penetration behaviors associated with nonpersistent virus transmission such as time to first intracellular puncture (potential drop), number of potential drops, duration of potential drop, duration of potential drop subphase II-3, and number of potential drops with subphase II-3 pulses were significantly increased on virus-infected compared with noninfected Beauregard, but greatly reduced on virus-infected compared with noninfected I. hederacea plants. Stylet penetration behaviors associated with host acceptance such as reduced nonprobing duration and nonprobing events were greater on virus-infected compared with noninfected Beauregard plants. In contrast, on Evangeline, I. cordatotriloba and I. hederacea stylet penetration behaviors by M. persicae indicate it had less preference for virus-infected compared with noninfected plants.


Assuntos
Afídeos/fisiologia , Ipomoea/virologia , Potyvirus/fisiologia , Animais , Comportamento Alimentar , Ipomoea/crescimento & desenvolvimento , Doenças das Plantas/virologia , Dinâmica Populacional
3.
Res Dev Disabil ; 151: 104783, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38924954

RESUMO

Over 50 % of children and youth with cerebral palsy (CP) experience mental health challenges, with anxiety and depression most common. Youth with CP also experience several physiological symptoms such as fatigue, pain, sedentary lifestyle, and sleep disturbances that impact their daily living; however, little is known about the impact of these symptoms on mental health outcomes in these youth. This study addressed this gap and examined the individual and cumulative impacts of physiological symptoms on anxiety and depression symptoms in youth with CP. Forty youth with CP aged 8 to 18 years, and their caregiver, participated in this cross-sectional observational study. Pain, fatigue, anxiety, and depressive symptoms were measured using caregiver- and self-reported questionnaires and participants wore accelerometers for seven consecutive days, providing non-invasive physical activity and sleep pattern data. Youth with CP experienced substantial physiological symptoms and elevated anxiety and depression symptoms. Linear regression models determined that all physiological factors were predictive of caregiver-reported youth anxiety (R2 = 0.23) and youth depressive symptoms (R2 = 0.48). Fatigue, pain severity, sleep efficiency, and physical activity outcomes individually and cumulatively contributed to caregiver-reported youth anxiety and depression symptoms. These findings highlight the important role of physiological symptoms as potential risk factors and potential targets for intervention for mental health issues for in youth with CP.


Assuntos
Ansiedade , Paralisia Cerebral , Depressão , Fadiga , Dor , Transtornos do Sono-Vigília , Humanos , Paralisia Cerebral/psicologia , Paralisia Cerebral/fisiopatologia , Paralisia Cerebral/complicações , Masculino , Feminino , Adolescente , Ansiedade/psicologia , Ansiedade/epidemiologia , Criança , Depressão/psicologia , Depressão/epidemiologia , Estudos Transversais , Fadiga/psicologia , Fadiga/fisiopatologia , Transtornos do Sono-Vigília/psicologia , Transtornos do Sono-Vigília/epidemiologia , Transtornos do Sono-Vigília/fisiopatologia , Dor/psicologia , Dor/fisiopatologia , Comportamento Sedentário , Exercício Físico/psicologia , Cuidadores/psicologia , Saúde Mental , Acelerometria , Autorrelato , Inquéritos e Questionários
4.
J Affect Disord ; 358: 163-174, 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-38718944

RESUMO

BACKGROUND: Individuals with prenatal alcohol exposure (PAE) commonly experience co-occurring diagnoses, which are often overlooked and misdiagnosed and have detrimental impacts on accessing appropriate services. The prevalence of these co-occurring diagnoses varies widely in the existing literature and has not been examined in PAE without an FASD diagnosis. METHOD: A search was conducted in five databases and the reference sections of three review papers, finding a total of 2180 studies. 57 studies were included in the final analysis with a cumulative sample size of 29,644. Bayesian modeling was used to determine aggregate prevalence rates of co-occurring disorders and analyze potential moderators. RESULTS: 82 % of people with PAE had a co-occurring diagnosis. All disorders had a higher prevalence in individuals with PAE than the general population with attention deficit hyperactivity disorder, learning disorder, and intellectual disability (ID) being the most prevalent. Age, diagnostic status, and sex moderated the prevalence of multiple disorders. LIMITATIONS: While prevalence of disorders is crucial information, it does not provide a direct representation of daily functioning and available supports. Results should be interpreted in collaboration with more individualized research to provide the most comprehensive representation of the experience of individuals with PAE. CONCLUSIONS: Co-occurring diagnoses are extremely prevalent in people with PAE, with older individuals, females, and those diagnosed with FASD being most at risk for having a co-occurring disorder. These findings provide a more rigorous examination of the challenges faced by individuals with PAE than has existed in the literature, providing clinicians with information to ensure early identification and effective treatment of concerns to prevent lifelong challenges.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade , Comorbidade , Efeitos Tardios da Exposição Pré-Natal , Humanos , Feminino , Gravidez , Prevalência , Efeitos Tardios da Exposição Pré-Natal/epidemiologia , Transtorno do Deficit de Atenção com Hiperatividade/epidemiologia , Transtornos do Espectro Alcoólico Fetal/epidemiologia , Masculino , Deficiência Intelectual/epidemiologia , Deficiências da Aprendizagem/epidemiologia , Teorema de Bayes , Adulto , Transtornos Mentais/epidemiologia , Criança
5.
Plant Dis ; 97(1): 53-61, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30722262

RESUMO

Sweet potato feathery mottle virus (SPFMV), Sweet potato virus G (SPVG), and Sweet potato virus 2 (SPV2) are sweetpotato (Ipomoea batatas) potyviruses nonpersistently transmitted by aphids. Our objective was to determine how aphid abundance, aphid species diversity, and virus titers relate to the spread of SPFMV, SPVG, and SPV2 in Louisiana and Mississippi sweetpotato fields. The most abundant aphid species were Aphis gossypii, Myzus persicae, Rhopalosiphum padi, and Therioaphis trifolii. Aphids were captured during the entire crop cycle but virus infection of sentinel plants occurred mainly during the months of June to August. SPFMV was more commonly detected than SPVG or SPV2 in sentinel plants. Virus titers for SPFMV were higher in samples beginning in late June. Because significant aphid populations were present during April to June when virus titers were low in sweetpotato and there was very little virus infection of sentinel plants, low virus titers may have limited aphid acquisition and transmission opportunities. This is the first study to comprehensively examine aphid transmission of potyviruses in sweetpotato crops in the United States and includes the first report of R. maidis and R. padi as vectors of SPFMV, though they were less efficient than A. gossypii or M. persicae.

6.
J Econ Entomol ; 106(4): 1566-73, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24020267

RESUMO

Three aphid species, Aphis gossypii Glover and Myzus persicae (Sulzer) (efficient sweetpotato potyvirus vectors) and Rhopalosiphum padi (L.) (an inefficient vector), are commonly found in sweet potato, Ipomoea batatas (L.), in Louisiana. Field-grown sweet potatoes are naturally infected with several potyviruses: Sweet potato feathery mottle virus, Sweet potato virus G, and Sweet potato virus 2. Thus, these aphids commonly encounter virus-infected hosts. What is not known is how each of these aphids responds to sweet potato, either infected or virus-free. The objectives of this study were to 1) determine if these aphid species can colonize mixed virus-infected sweet potato 'Beauregard', and if so, 2) determine the effects of virus infection on the population dynamics of each aphid. A. gossypii failed to larviposit and R. padi deposited a single nymph that died within a day on mixed virus-infected Beauregard. M. persicae larviposited and colonized Beauregard and further life-table analyses were warranted. M. persicae had a significantly greater reproduction on sweet potato cultivars Beauregard and 'Evangeline' with mixed virus infection compared with noninfected plants. On morning glory species, Ipomoea cordatotriloba (Dennestedt) and Ipomoea hederacea (Jacquin), M. persicae had a significantly lower reproduction on Sweet potato feathery mottle virus-infected compared with noninfected plants.


Assuntos
Afídeos/fisiologia , Ipomoea/virologia , Vírus de Plantas/fisiologia , Potyvirus/fisiologia , Animais , Afídeos/virologia , Cadeia Alimentar , Ipomoea/crescimento & desenvolvimento , Tábuas de Vida , Louisiana , Reprodução , Especificidade da Espécie
7.
Plant Dis ; 96(9): 1331-1336, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30727156

RESUMO

Sweetpotato feathery mottle virus (SPFMV) is a nonpersistently transmitted virus known to infect sweetpotato (Ipomoea batatas) and wild morning glory plants. SPFMV is vectored by various aphid species, among them the green peach aphid, Myzus persicae, and the cotton aphid, Aphis gossypii. Our objective was to determine whether differences in acquisition hosts (sweetpotato and morning glory), aphid species (M. persicae and A. gossypii), and infection status (single versus mixed infection) influenced transmission of SPFMV. SPFMV transmission from I. hederacea with a natural mixed infection by A. gossypii (39%) was significantly greater than in other host-virus combinations. Successful transmissions by A. gossypii were significantly greater compared with M. persicae in all host-virus combinations. Virus titers in source leaves were significantly greater in single- and mixed-infected I. hederacea and single-infected I. cordatotriloba compared with other host-virus combinations. There was a significant positive correlation between virus titer and transmission by both aphid species. These results suggest that, under controlled conditions, SPFMV is more readily transmitted from infected morning glory plants than from sweetpotato. Additionally, mixed-infected plants are better virus sources for transmission than single-infected, and A. gossypii is a more efficient vector than M. persicae under laboratory conditions.

8.
AJNR Am J Neuroradiol ; 43(10): 1508-1515, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36137658

RESUMO

BACKGROUND AND PURPOSE: Pediatric posterior fossa tumors often present with hydrocephalus; postoperatively, up to 25% of patients develop cerebellar mutism syndrome. Arterial spin-labeling is a noninvasive means of quantifying CBF and bolus arrival time. The aim of this study was to investigate how changes in perfusion metrics in children with posterior fossa tumors are modulated by cerebellar mutism syndrome and hydrocephalus requiring pre-resection CSF diversion. MATERIALS AND METHODS: Forty-four patients were prospectively scanned at 3 time points (preoperatively, postoperatively, and at 3-month follow-up) with single- and multi-inflow time arterial spin-labeling sequences. Regional analyses of CBF and bolus arrival time were conducted using coregistered anatomic parcellations. ANOVA and multivariable, linear mixed-effects modeling analysis approaches were used. The study was registered at clinicaltrials.gov (NCT03471026). RESULTS: CBF increased after tumor resection and at follow-up scanning (P = .045). Bolus arrival time decreased after tumor resection and at follow-up scanning (P = .018). Bolus arrival time was prolonged (P = .058) following the midline approach, compared with cerebellar hemispheric surgical approaches to posterior fossa tumors. Multivariable linear mixed-effects modeling showed that regional perfusion changes were more pronounced in the 6 children who presented with symptomatic obstructive hydrocephalus requiring pre-resection CSF diversion, with hydrocephalus lowering the baseline mean CBF by 20.5 (standard error, 6.27) mL/100g/min. Children diagnosed with cerebellar mutism syndrome (8/44, 18.2%) had significantly higher CBF at follow-up imaging than those who were not (P = .040), but no differences in pre- or postoperative perfusion parameters were seen. CONCLUSIONS: Multi-inflow time arterial spin-labeling shows promise as a noninvasive tool to evaluate cerebral perfusion in the setting of pediatric obstructive hydrocephalus and demonstrates increased CBF following resolution of cerebellar mutism syndrome.


Assuntos
Neoplasias Encefálicas , Hidrocefalia , Neoplasias Infratentoriais , Mutismo , Criança , Humanos , Neoplasias Encefálicas/patologia , Hidrocefalia/diagnóstico por imagem , Hidrocefalia/cirurgia , Neoplasias Infratentoriais/diagnóstico por imagem , Neoplasias Infratentoriais/cirurgia , Perfusão , Complicações Pós-Operatórias , Marcadores de Spin , Estudos Prospectivos
13.
Magn Reson Med ; 62(6): 1646-51, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19785020

RESUMO

Gliomas are the most common primary brain tumors and the majority are highly malignant, with one of the worst prognoses for patients. Gliomas are characterized by invasive growth into normal brain tissue that makes complete surgical resection and accurate radiotherapy planning extremely difficult. We have performed independent component analysis of magnetic resonance spectroscopy imaging data from human gliomas to segment brain tissue into tumor core, tumor infiltration, and normal brain, with confirmation by diffusion tensor imaging analysis. Our data are consistent with previous studies that compared anomalies in isotropic and anisotropic diffusion images to determine regions of potential glioma infiltration. We show that coefficients of independent components can be used to create colored images for easy visual identification of regions of infiltrative tumor growth.


Assuntos
Biomarcadores Tumorais/análise , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/metabolismo , Imagem de Difusão por Ressonância Magnética/métodos , Glioma/diagnóstico , Glioma/metabolismo , Espectroscopia de Ressonância Magnética/métodos , Algoritmos , Humanos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Proteínas de Neoplasias/análise , Reconhecimento Automatizado de Padrão/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
14.
Plant Dis ; 93(9): 896-905, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30754532

RESUMO

Bacterial panicle blight (BPB) is among the three most limiting rice diseases in Louisiana and the southern United States. The identity and characterization of pathogens associated with this disease was unclear. This research details studies carried out on the pathogens causing BPB on rice in Louisiana and other rice producing southern states. Bacterial strains were isolated from BPB-infected sheath, panicle, or grain samples collected from rice fields in Louisiana, Arkansas, Texas, and Mississippi. In greenhouse inoculation tests, 292 of 364 strains were pathogenic on rice seedlings or panicles. Identification of strains in the pathogen complex by growth on S-PG medium, carbon source utilization profile (Biolog), cellular fatty acid analysis, and polymerase chain reaction (PCR) methods revealed that 76 and 5% of the strains were Burkholderia glumae and B. gladioli, respectively. The other strains have not been conclusively identified. Although strains of both species produced similar symptoms on rice, B. glumae strains were generally more aggressive and caused more severe symptoms on rice than B. gladioli. Virulent strains of both species produced toxoflavin in culture. The two species had similar growth responses to temperature, and optima ranged from 38 to 40°C for B. glumae and 35 to 37°C for B. gladioli. PCR was the most sensitive and accurate method tested for identifying the bacterial pathogens to the species level. The 16S rDNA gene and 16S-23S rDNA internal transcribed spacer (ITS) region sequences of the B. glumae and B. gladioli strains from rice showed more than 99% sequence homology with published sequences. A real-time PCR system was developed to detect and quantify this pathogen from infected seed lots. Our results clearly indicate that B. glumae and B. gladioli were the major pathogens causing BPB in the southern United States.

15.
Eur J Clin Nutr ; 60(9): 1122-9, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16670695

RESUMO

OBJECTIVE: We tested the relative importance of a low-glycemic response versus a high glycemic response breakfast meal on postprandial serum glucose, insulin and free fatty acid (FFA) responses after consumption of a standardized mid-day meal in adult individuals with Type 2 diabetes mellitus (DM). DESIGN: Following an overnight fast of 8-10 h, a randomized crossover intervention using control and test meals was conducted over a 3-week-period. A fasting baseline measurement and postprandial measurements at various time intervals after the breakfast and mid-day meal were taken. SUBJECTS: Forty-five Type 2 DM subjects completed the requirements and were included in the study results. INTERVENTIONS: Two different breakfast meals were administered during the intervention: (A) a high glycemic load breakfast meal consisting of farina (kJ 1833; carbohydrate (CHO) 78 g and psylium soluble fiber 0 g), (B) a low-glycemic load breakfast meal consisting of a fiber-loop cereal (kJ 1515; CHO 62 g and psyllium soluble fiber 6.6 g). A standardized lunch was provided approximately 4 h after breakfast. Blood plasma concentrations and area under the curve (AUC) values for glucose, insulin and FFA were measured in response to the breakfast and mid-day lunch. Statistical analyses were performed using SAS software (8.02). Comparisons between diets were based on adjusted Bonferroni t-tests. RESULTS: In post-breakfast analyses, Breakfast B had significantly lower area under the curve (AUC) values for plasma glucose and insulin compared to Breakfast A (P<0.05) (95% confidence level). The AUC values for FFA were higher for Breakfast B than for Breakfast A (P<0.05) (95% confidence level). Post-lunch analyses indicated similar glucose responses for the two breakfast types. Insulin AUC values for Breakfasts B were significantly lower than Breakfast A (P<0.05) (95% confidence level). The AUC values for FFA were unaffected by breakfast type. CONCLUSIONS: These data indicate that ingesting a low-glycemic load meal containing psyllium soluble fiber at breakfast significantly improves the breakfast postprandial glycemic, insulinemic and FFA responses in adults with Type 2 DM. These data revealed no residual postprandial effect of the psyllium soluble fiber breakfast meal beyond the second meal consumed. Thus, there was no evidence of an improvement postprandially in the glycemic, insulinemic and FFA responses after the consumption of the lunch meal.


Assuntos
Glicemia/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Metabolismo Energético/fisiologia , Ácidos Graxos não Esterificados/sangue , Índice Glicêmico , Insulina/metabolismo , Adulto , Idoso , Área Sob a Curva , Estudos Cross-Over , Diabetes Mellitus Tipo 2/sangue , Dieta , Carboidratos da Dieta/administração & dosagem , Carboidratos da Dieta/metabolismo , Fibras na Dieta/administração & dosagem , Fibras na Dieta/metabolismo , Jejum , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Prandial , Fatores de Tempo
16.
J Natl Cancer Inst ; 67(5): 1031-9, 1981 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-7029095

RESUMO

The indirect, labeled antibody and peroxidase-antiperoxidase complex (PAP) methods were studied to determine their sensitivity in detecting carcinoembryonic antigen (CEA) in conventionally processed specimens of morphologically normal human colon mucosa. CEA-positive staining was demonstrated in 13 of 19 specimens reacted with the PAP method, whereas only 4 of these specimens stained positive with the labeled antibody procedure. Detection of CEA with either technique was unrelated to normal mucosa content of antigen as determined by radioimmunoassay. Tissue fixation in 95% ethanol 1% acetic acid (EA) resulted in an enhanced and defined cytoplasmic staining of the normal colon cell lining the mucosal surface and upper levels of the glandular crypts. Cytoplasmic localization in Formalin-fixed specimens was absent or markedly reduced. Colon goblet cells and the small intestinal epithelium were CEA-negative in both Formalin- and EA-fixed specimens. These results show that the PAP immunoperoxidase method is more sensitive than the indirect, labeled antibody procedure in detecting CEA in morphologically normal colon mucosa. Furthermore, staining of tissues fixed in EA demonstrated that CEA is a product of the columnar epithelial cell and is not associated with goblet cells.


Assuntos
Antígeno Carcinoembrionário/análise , Técnicas Imunoenzimáticas , Mucosa Intestinal/imunologia , Colo/análise , Colo/citologia , Técnicas de Cultura , Citoplasma/imunologia , Estudos de Avaliação como Assunto , Humanos , Técnicas Imunológicas
17.
Plant Dis ; 90(10): 1347-1352, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30780944

RESUMO

Sweet potato virus disease (SPVD) is the most serious viral disease of sweetpotato globally. This disease is caused by the synergistic interaction between the aphid-transmitted potyvirus Sweet potato feathery mottle virus (SPFMV) and the whitefly-transmitted crinivirus Sweet potato chlorotic stunt virus (SPCSV). In sweetpotato, titers of SPFMV have been shown to be significantly enhanced when coinfecting with SPCSV. In this study, the effect of SPCSV on titers of different potyviruses and potyvirus strains infecting sweetpotato in the United States was investigated using real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR). No significant difference was observed in titers of the russet crack strain of SPFMV (SPFMV-RC), Ipomoea vein mosaic virus (IVMV), and Sweet potato virus G (SPVG) between single and mixed infections. Titers of all potyviruses and potyvirus strains evaluated were enhanced in the presence of SPCSV, suggesting that a conserved mechanism may underlie these interactions. Titers of the common strain of SPFMV (SPFMV-C), which did not cause SPVD-like symptoms when coinfecting with SPCSV, were also significantly enhanced in the presence of SPCSV. Furthermore, titers of SPCSV were found to be lower in treatments involving pairwise infections compared with plants infected by SPCSV alone. The degree of potyvirus titer enhancement did not correspond to the severity of symptoms observed in certain treatments involving pairwise infections.

18.
Plant Dis ; 90(6): 783-788, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30781240

RESUMO

Viral diseases, especially those caused by mixed infections, are among the economically most important diseases of sweetpotato. The difficulties inherent in detecting, quantifying, and isolating viruses directly from sweetpotato have impeded progress in sweetpotato virus research. Real-time polymerase chain reaction (PCR) assays were developed for the detection and relative quantification in singleplex reactions of the potyviruses Sweet potato feathery mottle virus (SPFMV), Sweet potato virus G (SPVG), and Ipomoea vein mosaic virus (IVMV); the crinivirus Sweet potato chlorotic stunt virus (SPCSV); and the begomovirus Sweet potato leaf curl virus(SPLCV) directly from infected sweetpotato plants. There was no significant effect from potential inhibitors in total nucleic acid extracts from sweetpotato leaves on the performance of the real-time PCR assays. Virus titers of SPFMV, IVMV, and SPVG were quantified using real-time PCR and found to be lower in singly infected sweetpotato plants compared with singly infected Brazilian morning-glory (Ipomoea setosa Ker.) and I. nil cv. Scarlet O'Hara plants. Real-time PCR was a more efficient detection method for SPLCV than conventional PCR assay.

19.
Plant Dis ; 90(1): 83-88, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30786480

RESUMO

During cycles of vegetative propagation, sweetpotato accumulates viruses that are thought to contribute to decline in yield and quality of cultivars, but the effects of specific viruses, many of which have been described only recently, are unknown. Field plots planted with graft-inoculated plants of a virus-tested (VT) mericlone of cv. Beauregard were used to assess the effects of three common potyviruses, Sweet potato feathery mottle virus (SPFMV), Sweet potato virus G (SPVG), and Ipomoea vein mosaic virus (IVMV); and a begomovirus, Sweet potato leaf curlvirus (SPLCV), compared with natural inoculum introduced by grafting plants from farmers' stock. Single infections with SPFMV, SPVG, or IVMV did not significantly affect yield, whereas mixed infections with SPFMV + SPVG or SPFMV + SPVG + IVMV resulted in mean yields 14% less than the VT controls. Infection with SPLCV resulted in mean yields 26% less than the VT controls, despite not causing symptoms on the foliage. However, grafting with farmers' plants infected with an unknown mixture of pathogens resulted in mean yields 31 to 44% less than the VT controls. Infection with potyviruses resulted in storage roots with tan periderm and infection with SPLCV induced darker periderm than the rosy VT controls. Infection with the viruses known to occur commonly in the United States did not reproduce the magnitude of yield reduction that has been observed with naturally infected plants.

20.
Plant Dis ; 90(6): 832, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30781266

RESUMO

Previous surveys for viruses in sweetpotatoes (Ipomoea batatas) in Africa did not assay for the presence of begomoviruses such as Sweet potato leaf curl virus (SPLCV), which have been found recently in the Americas and Asia. Symptomatic sweetpotato plants, including some with leaf curling symptoms similar to those observed in SPLCV-infected sweet-potato plants (2), were collected from a germplasm collection plot at Kakamega Research Station in Western Kenya during February 2005. Whiteflies, the vectors for begomoviruses, were observed in the same plots. Ipomoea setosa plants graft-inoculated with scions from the symptomatic sweetpotato developed leaf curl, leaf roll, interveinal chlorosis, and stunting symptoms similar to those caused by infection with SPLCV alone or in combination with Sweet potato feathery mottle virus. Total DNA was isolated from 10 I. setosa plants using the GenElute Plant Genomic DNA Kit (Sigma-Aldrich Inc., St. Louis, MO). Sweetpotato cuttings from 39 clones, selected from the Kenyan germplasm collection for their resistance or susceptibility to sweetpotato virus disease (SPVD), were sent to the Plant Germplasm Quarantine Office of USDA-ARS. The cuttings were planted in a greenhouse. Total DNA was extracted from sweetpotato leaves 1 month later using a cetyltrimethylammoniumbromide (CTAB) extraction method (1). Degenerate primers SPG1/SPG2, developed for PCR detection of begomoviruses (1), amplified a 912-bp DNA fragment from 3 of 10 DNA extracts from I. setosa and 5 of 39 sweetpotato plants held in quarantine. The primers anneal to regions of open reading frame (ORF) AC2 and ORF AC1 that are highly conserved in begomoviruses infecting sweetpotato. SPLCV-specific primers PW285-1/PW285-2 (2) amplified a 512-bp DNA fragment of ORF AC1 from seven samples (two from I. setosa and five from I. batatas). Amplicons from three independent PCR assays of two samples and single PCR assays of four additional samples were cloned into the pGEM-T Easy vector. Clone inserts were sequenced, and compared with sequences deposited in GenBank using the basic local alignment search tool (BLAST). Sequences were closely related to SPLCV (GenBank Accession No. AF104036) with nucleotide sequence identities varying from 93% (GenBank Accession No. DQ361004) to 97% (GenBank Accession No. DQ361005). The presence of the virus poses a challenge to the dissemination of planting materials in the region because begomovirus-infected plants often do not show symptoms. To our knowledge, this is the first report of a begomovirus infecting sweetpotato in Kenya or the East African Region. References: (1) R. Li et al. Plant Dis. 88:1347, 2004. (2) P. Lotrakul et al. Plant Dis. 82:1253, 1998.

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