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1.
Plant Dis ; 106(6): 1736-1742, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34962417

RESUMO

Ralstonia solanacearum is a pathogen causing bacterial wilt disease of potato, resulting in 70% potato production losses in Kenya. A study was conducted to determine the diversity of R. solanacearum species complex strains within the main potato-growing regions of Kenya. Potato tubers were collected in different potato-growing regions of Kenya from visibly wilted potato plants as well as samples of tomato, irrigation water, and cultures for pathogen isolation. Genomic DNA was isolated from 135 purified cultures of RSSC isolates and PCR-amplified using multiplex and sequevar primers targeting the endoglucanase (egl) partial gene sequences. Pathogenicity tests using R. solanacearum strain (phylotype II sequevar I) were done on the cultivars Kenya Karibu, Shangi, Chulu, Wanjiku, and MoneyMaker. Phylogenetic analysis of the partial egl gene identified two genospecies, R. pseudosolanacearum sp. nov. (1.5%) and R. solanacearum (98.5%). All R. solanacearum strains clustered in sequevar I and were distributed in all the potato-growing regions surveyed. The cultivars were grown in a greenhouse for two cycles in a randomized complete block design and inoculated with R. solanacearum strain. The severity scores were assessed and the area under the disease progress curve (AUDPC) was determined. All the cultivars tested for pathogenicity exhibited wilting symptoms at varying intervals after infection, with none showing complete resistance to R. solanacearum. Cultivar Shangi exhibited minimum disease severity and progression of 41.14% and AUDPC of 1041.7, respectively, while 'Kenya Karibu' was the most susceptible with a high progression rate of 68.24% and AUDPC of 1897.5, respectively. 'MoneyMaker', 'Chulu', and 'Wanjiku' showed no significant difference in disease severity, depicting a simultaneous rate of infection among them. These findings provide valuable information to better understand the pathogen genetic diversity in Kenya and how it spreads.


Assuntos
Filogenia , Doenças das Plantas , Ralstonia solanacearum , Solanum tuberosum , Quênia , Doenças das Plantas/microbiologia , Ralstonia solanacearum/genética , Solanum tuberosum/microbiologia
2.
Int J Food Sci Technol ; 56(3): 1076-1092, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33776222

RESUMO

This review of the literature on varietal change in sub-Saharan Africa looks in detail at adoption of new varieties of bananas in Uganda, cassava in Nigeria, potato in Kenya, sweetpotato in Uganda and yams in Côte d'Ivoire. The review explored three hypotheses about drivers of varietal change. There was a strong confirmation for the hypothesis that insufficient priority given to consumer-preferred traits by breeding programmes contributes to the limited uptake of modern varieties (MVs) and low varietal turnover. Lack of evidence meant the second hypothesis of insufficient attention to understanding and responding to gender differences in consumer preferences for quality and post-harvest traits was unresolved. The evidence on the third hypothesis about the informal seed system contributing to slow uptake of MVs was mixed. In some cases, the informal system has contributed to rapid uptake of MVs, but often it appears to be a barrier with inconsistent varietal naming a major challenge.

3.
Alzheimer Dis Assoc Disord ; 34(3): 191-197, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32483017

RESUMO

BACKGROUND: Norms for the Uniform Data Set Version 3 Neuropsychological Battery are available for cognitively normal individuals based on age, education, and sex; however, these norms do not include race. We provide expanded norms for African Americans and whites. METHODS: Data from 32 Alzheimer's Disease Centers (ADCs) and ADC affiliated cohorts with global Clinical Dementia Rating Scale (CDR) Dementia Staging Instrument scores of 0 were included. Descriptive statistics for each test were calculated by age, sex, race, and education. Multiple linear regressions were conducted to estimate the effect of each demographic variable; squared semipartial correlation coefficients measured the relative importance of variables. RESULTS: There were 8313 participants (16% African American) with complete demographic information, ranging from 6600 to 7885 depending on the test. Lower scores were found for older and less educated groups, and African Americans versus whites. Education was the strongest predictor for most tests, followed in order by age, race, and sex. Quadratic terms were significant for age and education, indicating some nonlinearity, but did not substantially increase R. CONCLUSIONS: Although race-based norms represent incomplete proxies for other sociocultural variables, the appropriate application of these norms is important given the potential to improve diagnostic accuracy and to reduce misclassification bias in cognitive disorders of aging such as Alzheimer disease.


Assuntos
Envelhecimento , Negro ou Afro-Americano/estatística & dados numéricos , Voluntários Saudáveis , Testes Neuropsicológicos , População Branca/estatística & dados numéricos , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/diagnóstico , Bases de Dados Factuais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos/normas , Testes Neuropsicológicos/estatística & dados numéricos , Estados Unidos
4.
J Appl Gerontol ; 39(10): 1059-1068, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-31535922

RESUMO

The "Great Village," a cultural adaptation of a psychoeducation intervention the "Savvy Caregiver" for African American caregivers of persons living with dementia (PLwD), aims to develop caregivers' skills and improve the quality of the lives of both the PLwD and their caregivers. The goal of this study was to determine the effectiveness of the Great Village on depressive symptoms, anxiety, burden, and mastery in African American caregivers (N = 142). A three-arm randomized control trial (Great Village, Great Village + exercise, and attention control) was conducted over a period of 6 months. Caregivers who received either Great Village or Great Village + exercise reported significant reduction in depressive symptoms and improvement in mastery. Caregivers who received only Great Village reported a reduction in anxiety. Receiving no intervention worsened caregiver burden. African American caregivers should receive culturally tailored interventions to support their health and well-being and improve their competence in caregiving.


Assuntos
Cuidadores , Demência , Adaptação Psicológica , Negro ou Afro-Americano , Ansiedade , Características Culturais , Demência/terapia , Depressão , Feminino , Humanos , Masculino , Qualidade de Vida
5.
Phytopathology ; 109(11): 1922-1931, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31272278

RESUMO

Bacterial wilt (BW) caused by the Ralstonia solanacearum species complex (RSSC) is a serious threat to potato production in Uganda. However, little is known about the extent of the disease and the type of the pathogen strains involved. A nationwide survey was conducted to study BW prevalence and incidence in potato, and potato tuber and stem samples of potential alternative hosts were collected for pathogen isolation. DNA was extracted from pure cultures for genetic diversity studies. The pathogen was phylotyped by multiplex PCR; then, a subset of isolates was typed at sequevar level. Isolates of the same sequevar were then haplotyped using multilocus tandem repeat sequence typing (TRST) schemes. BW prevalence and incidence in potato farms were 81.4 and 1.7%, respectively. Three RSSC phylotypes were identified, with the majority of the strains belonging to Phylotype II (80%) followed by Phylotype I (18.5%) and III (1.5%). Phylotype I strains belonged to Sequevar 31, and Phylotype II strains belonged to Sequevar 1. Potato-associated Phylotype II Sequevar 1 strains were more diverse (27 TRST haplotypes) than nonpotato Phylotype I (5 TRST haplotypes). Mapping of TRST haplotypes revealed that three TRST haplotypes of Phylotype II Sequevar 1 strains play an important epidemiological role in BW of potato in Uganda being disseminated via latently infected seed.[Formula: see text]Copyright © 2019 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.


Assuntos
Epidemiologia Molecular , Ralstonia solanacearum , Solanum tuberosum , Tipagem Molecular , Filogenia , Doenças das Plantas/microbiologia , Ralstonia solanacearum/classificação , Ralstonia solanacearum/genética , Solanum tuberosum/microbiologia , Uganda
6.
Plant Dis ; 103(5): 959-965, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30895864

RESUMO

Bacterial wilt caused by Ralstonia solanacearum is considered among the most damaging diseases of potato in Sub-Saharan Africa and the most significant biotic constraint of potato production alongside late blight. Unlike late blight, which can be managed by chemical means, R. solanacearum can only be managed through cultural methods and clean seed. Laboratory testing to certify seed before planting is required to confirm the absence of the pathogen in Kenya. A loop-mediated isothermal amplification (LAMP) assay was developed using the UDP-(3-O-acyl)-N-acetylglucosamine deacetylase gene (IpxC) to screen seed potato for R. solanacearum strains. The assay was assessed using DNA extracted from R. solanacearum and other soil and potato pathogens to demonstrate specificity and sensitivity. The LAMP assay was validated using field samples from different potato growing regions of Kenya collected over two growing seasons and compared with established nucleic acid and protein-based assays. The IpxC LAMP assay was found to be specific and sensitive to R. solanacearum, detecting as low as 2.5 pg/µl of R. solanacearum DNA. Of the 47 potentially infected field samples collected, both IpxC LAMP and quantitative polymerase chain reaction (PCR) detected R. solanacearum DNA in 90% of the samples, followed by conventional PCR (86%) and ELISA (75%). This IpxC LAMP assay is a promising diagnostic tool to rapidly screen for R. solanacearum in seed potato with high sensitivity in Kenya. Copyright © 2019 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .


Assuntos
Agricultura/métodos , Ensaio de Imunoadsorção Enzimática , Técnicas de Amplificação de Ácido Nucleico , Ralstonia solanacearum , Solanum tuberosum , Ensaio de Imunoadsorção Enzimática/normas , Quênia , Técnicas de Amplificação de Ácido Nucleico/normas , Doenças das Plantas/microbiologia , Ralstonia solanacearum/genética , Ralstonia solanacearum/isolamento & purificação , Solanum tuberosum/microbiologia
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