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1.
BMC Med Educ ; 18(1): 276, 2018 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-30466411

RESUMO

Following publication of the original article [1], the author reported that Fig. 1 was missing.

2.
BMC Med Educ ; 18(1): 236, 2018 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-30309368

RESUMO

BACKGROUND: Promoting cultural competence of health professionals working with Aboriginal and Torres Strait Islander communities is key to improving health outcomes. Cultural Educators and Cultural Mentors (CE/ CMs) have critical roles in Australian general practice training, yet these are not well understood. METHODS: Guided by a CE/CM Network, our research team including experienced CE/CMs, used surveys and semi-structured interviews to explore these roles and investigate best practice in employment and support. Participants sampled from stakeholders involved in general practice education across Australia included CE/CMs, Medical Educators, General Practice Supervisors and Registrars, and representatives of Regional Training Organisations, Indigenous Health Training Posts and other key organisations. We undertook thematic analysis using a framework approach, refined further in team discussions that privileged views of CE/ CM members. RESULTS: Participants comprised 95 interviewees and 55 survey respondents. We organised our findings under three overarching themes: understandings about cultural education and mentoring; employment and support of CE/CMs; and delivery and evaluation of cultural education and mentoring. Our findings supported a central role for Aboriginal and Torres Strait Islander CE/CMs in face-to-face Registrar education about culture and history and related impacts on health and healthcare. Cultural education was reported to provide base-line learning as preparation for clinical practice whilst cultural mentoring was seen as longitudinal, relationship-based learning. Mentoring was particularly valued by Registrars working in Aboriginal and Torres Strait Islander communities. Challenges described with employment and support included difficulties in finding people with skills and authority to undertake this demanding work. Remuneration was problematic, particularly for CMs whose work-time is difficult to quantify, and who are often employed in other roles and sometimes not paid. Other improved support recommended included appropriate employment terms and conditions, flexibility in role definitions, and professional development. Recommendations concerning implementation and evaluation included valuing of cultural education, greater provision of mentoring, partnerships with Medical Educators, and engagement of CE/CMs in rigorous evaluation and assessment processes. CONCLUSIONS: Our research highlights the importance of the unique CE/CM roles and describes challenges in sustaining them. Professional and organisational support is needed to ensure delivery of respectful and effective cultural education within general practitioner training.

5.
Theor Appl Genet ; 129(8): 1507-17, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27160855

RESUMO

KEY MESSAGE: SNP markers were developed for the OWBM resistance gene Sm1 that will be useful for MAS. The wheat Sm1 region is collinear with an inverted syntenic interval in B. distachyon. Orange wheat blossom midge (OWBM, Sitodiplosis mosellana Géhin) is an important insect pest of wheat (Triticum aestivum) in many growing regions. Sm1 is the only described OWBM resistance gene and is the foundation of managing OWBM through host genetics. Sm1 was previously mapped to wheat chromosome arm 2BS relative to simple sequence repeat (SSR) markers and the dominant, sequence characterized amplified region (SCAR) marker WM1. The objectives of this research were to saturate the Sm1 region with markers, develop improved markers for marker-assisted selection (MAS), and examine the synteny between wheat, Brachypodium distachyon, and rice (Oryza sativa) in the Sm1 region. The present study mapped Sm1 in four populations relative to single nucleotide polymorphisms (SNPs), SSRs, Diversity Array Technology (DArT) markers, single strand conformation polymorphisms (SSCPs), and the SCAR WM1. Numerous high quality SNP assays were designed that mapped near Sm1. BLAST delineated the syntenic intervals in B. distachyon and rice using gene-based SNPs as query sequences. The Sm1 region in wheat was inverted relative to B. distachyon and rice, which suggests a chromosomal rearrangement within the Triticeae lineage. Seven SNPs were tested on a collection of wheat lines known to carry Sm1 and not to carry Sm1. Sm1-flanking SNPs were identified that were useful for predicting the presence or absence of Sm1 based upon haplotype. These SNPs will be a major improvement for MAS of Sm1 in wheat breeding programs.


Assuntos
Mapeamento Cromossômico , Ligação Genética , Polimorfismo de Nucleotídeo Único , Sintenia , Triticum/genética , Animais , Brachypodium/genética , Chironomidae , DNA de Plantas/genética , Genes de Plantas , Marcadores Genéticos , Haplótipos , Oryza/genética , Fenótipo
6.
Theor Appl Genet ; 129(3): 485-93, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26660463

RESUMO

KEY MESSAGE: Genetic and mutational analyses of wheat leaf rust resistance gene Lr13 and hybrid necrosis gene Ne2 m indicated that they are the same gene. Hybrid necrosis in wheat characterized by chlorosis and eventual necrosis of plant tissues in certain wheat hybrids is controlled by the interaction of complementary dominant genes Ne1 and Ne2 located on chromosome arms 5BL and 2BS, respectively. Multiple alleles at each locus can be identified by differences in necrotic phenotypes when varieties are crossed with a fixed accession of the other genotype. Some of at least five Ne2 alleles were described as s (strong), m (medium) and w (weak); alleles of Ne1 were similarly described. Ne2m causes moderate necrosis in hybrids with genotypes having Ne1s. Ne2 is located on chromosome arm 2BS in close proximity to Lr13. Most wheat lines with Ne2m carry Lr13, and all wheat lines with Lr13 appear to carry Ne2m. To further dissect the relationship between Lr13 and Ne2m, more than 350 crosses were made between cv. Spica (Triticum aestivum) or Kubanka (T. durum) carrying Ne1s and recombinant inbred lines or doubled haploid lines from three crosses segregating for Lr13. F1 plants from lines carrying Lr13 crossed with Spica (Ne1s) always showed progressive necrosis; those lacking Lr13 did not. Four wheat cultivars/lines carrying Lr13 were treated with the mutagen EMS. Thirty-five susceptible mutants were identified; eight were distinctly less glaucous and late maturing indicative of chromosome 2B or sub-chromosome loss. Hybrids of phenotypically normal Lr13 mutant plants crossed with Spica did not produce symptoms of hybrid necrosis. Thus, Lr13 and one particular Ne2m allele may be the same gene.


Assuntos
Basidiomycota/patogenicidade , Resistência à Doença/genética , Doenças das Plantas/genética , Triticum/genética , Alelos , Mapeamento Cromossômico , Cruzamentos Genéticos , Genes Dominantes , Genes de Plantas , Marcadores Genéticos , Genótipo , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Triticum/microbiologia
8.
PLoS One ; 9(10): e109466, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25310300

RESUMO

The gastric pathogen Helicobacter pylori is one of the most genetically diverse of bacterial species. Much of its diversity stems from frequent mutation and recombination, preferential transmission within families and local communities, and selection during persistent gastric mucosal infection. MLST of seven housekeeping genes had identified multiple distinct H. pylori populations, including three from Africa: hpNEAfrica, hpAfrica1 and hpAfrica2, which consists of three subpopulations (hspWAfrica, hspCAfrica and hspSAfrica). Most detailed H. pylori population analyses have used strains from non-African countries, despite Africa's high importance in the emergence and evolution of humans and their pathogens. Our concatenated sequences from seven H. pylori housekeeping genes from 44 Gambian patients (MLST) identified 42 distinct sequence types (or haplotypes), and no clustering with age or disease. STRUCTURE analysis of the sequence data indicated that Gambian H. pylori strains belong to the hspWAfrica subpopulation of hpAfrica1, in accord with Gambia's West African location. Despite Gambia's history of invasion and colonisation by Europeans and North Africans during the last millennium, no traces of Ancestral Europe1 (AE1) population carried by those people were found. Instead, admixture of 17% from Ancestral Europe2 (AE2) was detected in Gambian strains; this population predominates in Nilo-Saharan speakers of North-East Africa, and might have been derived from admixture of hpNEAfrica strains these people carried when they migrated across the Sahara during the Holocene humid period 6,000-9,000 years ago. Alternatively, shared AE2 ancestry might have resulted from shared ancestral polymorphisms already present in the common ancestor of sister populations hpAfrica1 and hpNEAfrica.


Assuntos
Variação Genética , Helicobacter pylori/genética , Adolescente , Adulto , Idoso , Evolução Biológica , Criança , Pré-Escolar , Feminino , Gâmbia , Mucosa Gástrica/microbiologia , Genes Bacterianos , Genes Essenciais , Haplótipos , Infecções por Helicobacter/etnologia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/classificação , Helicobacter pylori/isolamento & purificação , Humanos , Masculino , Pessoa de Meia-Idade , Tipagem de Sequências Multilocus , Adulto Jovem
9.
Theor Appl Genet ; 127(9): 2005-9, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25112203

RESUMO

KEY MESSAGE: KU3198 is a common wheat accession that carries one novel leaf rust resistance (Lr) gene, Lr70 , and another Lr gene which is either novel, Lr52 or an allele of Lr52. Leaf rust, caused by Puccinia triticina Eriks. (Pt), is a broadly distributed and economically important disease of wheat. Deploying cultivars carrying effective leaf rust resistance (Lr) genes is a desirable method of disease control. KU3198 is a common wheat (Triticum aestivum L.) accession from the Kyoto collection that was highly resistant to Pt in Canada. An F2 population from the cross HY644/KU3198 showed segregation for two dominant Lr genes when tested with Pt race MBDS which was virulent on HY644. Multiple bulk segregant analysis (MBSA) was employed to find putative chromosome locations of these Lr genes using SSR markers that provided coverage of the genome. MBSA predicted that the Lr genes were located on chromosomes 5B and 5D. A doubled haploid population was generated from the cross of JBT05-714 (HY644*3/KU3198), a line carrying one of the Lr genes from KU3198, to Thatcher. This population segregated for a single Lr gene conferring resistance to Pt race MBDS, which was mapped to the terminal region of the short arm of chromosome 5B with SSR markers and given the temporary designation LrK1. One F3 family derived from the HY644/KU3198 F2 population that segregated only for the second Lr gene from KU3198 was identified. This family was treated as an F2-equivalent population and used for mapping the Lr gene, which was located to the terminal region of chromosome 5DS. As no other Lr gene has been mapped to 5DS, this gene is novel and has been designated as Lr70.


Assuntos
Basidiomycota/patogenicidade , Resistência à Doença/genética , Genes de Plantas , Doenças das Plantas/genética , Triticum/genética , Mapeamento Cromossômico , Cruzamentos Genéticos , DNA de Plantas/genética , Marcadores Genéticos , Repetições de Microssatélites , Análise de Sequência de DNA
10.
BMC Infect Dis ; 13: 422, 2013 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-24010891

RESUMO

BACKGROUND: Helicobacter pylori infection is acquired in early childhood and persists for life (or until eradication treatment is taken). Seropositivity of H. pylori at age 49-51 years was assessed in relation to socio-economic deprivation in early life and the timing of other childhood infections common at that time. METHODS: Prospectively collected socio-economic and morbidity data from the Newcastle Thousand Families study, a birth cohort established in 1947. H. pylori IgG seropositivity was assessed at 49-51 years and examined in relation to both whether the individual had been diagnosed with one of measles, mumps or chicken pox, and, if so, the age at first infection. This was done in logistic regression models, allowing adjustment for socio-economic status and housing quality in childhood. RESULTS: Adult H. pylori status was strongly linked to disadvantaged socio-economic status in early life (p ≤ 0.002), unlike measles, mumps and chicken pox which showed no associations. Early measles infection was independently associated with H. pylori seropositivity (p = 0.01). CONCLUSIONS: Of the four infectious diseases that we have studied, it appears that H. pylori differs from the others by the strength of association with socio economic deprivation in early childhood. Our findings further highlight the complex interaction between measles, childhood infections and other non-microbiological factors that occur within a whole population. These data suggest a strong association between H. pylori and deprivation and raise the possibility of an interaction between early measles exposure and increased risk of exposure to H. pylori infection.


Assuntos
Anticorpos Antibacterianos/imunologia , Infecções por Helicobacter/imunologia , Helicobacter pylori/imunologia , Pré-Escolar , Estudos de Coortes , Feminino , Infecções por Helicobacter/economia , Infecções por Helicobacter/epidemiologia , Infecções por Helicobacter/etiologia , Humanos , Masculino , Sarampo/complicações , Pessoa de Meia-Idade , Fatores de Risco , Fatores Socioeconômicos , Reino Unido/epidemiologia
11.
Eur J Epidemiol ; 28(3): 257-65, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23412929

RESUMO

Studies of the association between early life infections and cancer have produced inconsistent findings, possibly due to limited adjustment for confounding and retrospective designs. This study utilised data from the Newcastle Thousand Families Study, a prospective cohort of 1,142 individuals born in Newcastle-upon-Tyne in 1947, to assess the impact of various childhood infectious diseases on cancer mortality during ages 15-60 years. Detailed information was collected prospectively on a number of early life factors. Deaths from cancer during ages 15-60 years were analysed in relation to childhood infections, adjusting for potential early-life confounders, using Cox proportional-hazards regression. In a subsample who returned questionnaires at aged 49-51 years, additional adjustment was made for adult factors to predict death from cancer during ages 50-60 years. Childhood history of measles and influenza, were both independently associated with lower cancer mortality during ages 15-60 years (adjusted hazard ratios = 0.39, 95% CI 0.17-0.88 and 0.49, 95% CI 0.24-0.98 respectively). In contrast, childhood pertussis was associated with higher cancer mortality during ages 15-60 years (adjusted hazard ratio = 4.88, 95% CI 2.29-10.38). In the subsample with additional adjustment for adult variables, measles and pertussis remained significantly associated with cancer mortality during ages 50-60 years. In this pre-vaccination cohort, childhood infection with measles and influenza were associated with a reduced risk of death from cancer in adulthood, while pertussis was associated with an increased risk. While these results suggest some disease-specific associations between early-life infections and cancer, further studies are required to confirm the specific associations identified.


Assuntos
Envelhecimento/imunologia , Doenças Transmissíveis/epidemiologia , Mortalidade Prematura , Neoplasias/epidemiologia , Adolescente , Adulto , Distribuição por Idade , Fatores Etários , Doenças Transmissíveis/complicações , Feminino , Seguimentos , Humanos , Influenza Humana/mortalidade , Masculino , Sarampo/mortalidade , Pessoa de Meia-Idade , Neoplasias/etiologia , Razão de Chances , Valor Preditivo dos Testes , Modelos de Riscos Proporcionais , Estudos Prospectivos , Fatores de Risco , Fatores Socioeconômicos , Inquéritos e Questionários , Reino Unido/epidemiologia , Coqueluche/mortalidade , Adulto Jovem
12.
Theor Appl Genet ; 126(2): 443-9, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23052026

RESUMO

An important aspect of studying putative new genes in wheat is determining their position on the wheat genetic map. The primary difficulty in mapping genes is determining which chromosome carries the gene of interest. Several approaches have been developed to address this problem, each with advantages and disadvantages. Here we describe a new approach called multiple bulked segregant analysis (MBSA). A set of 423 simple sequence repeat (SSR) markers were selected based on profile simplicity, frequency of polymorphism, and distribution across the wheat genome. SSR primers were preloaded in 384-well PCR plates with each primer occupying 16 wells. In practice, 14 wells are reserved for "mini-bulks" that are equivalent to four gametes (e.g. two F(2) individuals) comprised of individuals from a segregated population that have a known homozygous genotype for the gene of interest. The remaining two wells are reserved for the parents of the population. Each well containing a mini-bulk can have one of three allele compositions for each SSR: only the allele from one parent, only the allele from the other parent, or both alleles. Simulation experiments were performed to determine the pattern of mini-bulk allele composition that would indicate putative linkage between the SSR in question and the gene of interest. As a test case, MBSA was employed to locate an unidentified stem rust resistance (Sr) gene in the winter wheat cultivar Norin 40. A doubled haploid (DH) population (n = 267) was produced from hybrids of the cross LMPG-6S/Norin 40. The DH population segregated for a single gene (χ (1:1) (2) = 0.093, p = 0.76) for resistance to Puccinia graminis f.sp. tritici race LCBN. Four resistant DH lines were included in each of the 14 mini-bulks for screening. The Sr gene was successfully located to the long arm of chromosome 2D using MBSA. Further mapping confirmed the chromosome location and revealed that the Sr gene was located in a linkage block that may represent an alien translocation. The new Sr gene was designated as Sr54.


Assuntos
Basidiomycota/fisiologia , Segregação de Cromossomos , Resistência à Doença/genética , Genes de Plantas/genética , Doenças das Plantas/microbiologia , Caules de Planta/genética , Triticum/genética , Basidiomycota/patogenicidade , Mapeamento Cromossômico , Cromossomos de Plantas/genética , Regulação da Expressão Gênica de Plantas , Marcadores Genéticos , Imunidade Inata , Repetições de Microssatélites/genética , Microscopia Eletrônica de Transmissão e Varredura , Fenótipo , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Caules de Planta/imunologia , Caules de Planta/microbiologia , Estações do Ano , Triticum/imunologia , Triticum/microbiologia
13.
Antimicrob Agents Chemother ; 57(3): 1231-7, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23263004

RESUMO

Helicobacter pylori is a globally important and genetically diverse gastric pathogen that infects most people in developing countries. Eradication efforts are complicated by antibiotic resistance, which varies in frequency geographically. There are very few data on resistance in African strains. Sixty-four Gambian H. pylori strains were tested for antibiotic susceptibility. The role of rdxA in metronidazole (Mtz) susceptibility was tested by DNA transformation and sequencing; RdxA protein variants were interpreted in terms of RdxA structure. Forty-four strains (69%) were resistant to at least 8 µg of Mtz/ml. All six strains from infants, but only 24% of strains from adults, were sensitive (P = 0.0031). Representative Mtz-resistant (Mtz(r)) strains were rendered Mtz susceptible (Mtz(s)) by transformation with a functional rdxA gene; conversely, Mtz(s) strains were rendered Mtz(r) by rdxA inactivation. Many mutations were found by Gambian H. pylori rdxA sequencing; mutations that probably inactivated rdxA in Mtz(r) strains were identified and explained using RdxA protein's structure. All of the strains were sensitive to clarithromycin and erythromycin. Amoxicillin and tetracycline resistance was rare. Sequence analysis indicated that most tetracycline resistance, when found, was not due to 16S rRNA gene mutations. These data suggest caution in the use of Mtz-based therapies in The Gambia. The increasing use of macrolides against respiratory infections in The Gambia calls for continued antibiotic susceptibility monitoring. The rich variety of rdxA mutations that we found will be useful in further structure-function studies of RdxA, the enzyme responsible for Mtz susceptibility in this important pathogen.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Farmacorresistência Bacteriana/genética , Infecções por Helicobacter/tratamento farmacológico , Helicobacter pylori/genética , Mutação , Nitrorredutases/genética , Adolescente , Adulto , Idoso , Amoxicilina/farmacologia , Criança , Pré-Escolar , Claritromicina/farmacologia , Análise Mutacional de DNA , Farmacorresistência Bacteriana/efeitos dos fármacos , Eritromicina/farmacologia , Feminino , Gâmbia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/efeitos dos fármacos , Helicobacter pylori/isolamento & purificação , Humanos , Lactente , Masculino , Metronidazol/farmacologia , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , RNA Ribossômico 16S/genética , Tetraciclina/farmacologia
14.
PLoS One ; 6(11): e27954, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22140492

RESUMO

BACKGROUND: The prevalence of Helicobacter pylori including strains with putatively virulent genotypes is high, whereas the H. pylori-associated disease burden is low, in Africa compared to developed countries. In this study, we investigated the prevalence of virulence-related H. pylori genotypes and their association with gastroduodenal diseases in The Gambia. METHODS AND FINDINGS: DNA extracted from biopsies and H. pylori cultures from 169 subjects with abdominal pain, dyspepsia or other gastroduodenal diseases were tested by PCR for H. pylori. The H. pylori positive samples were further tested for the cagA oncogene and vacA toxin gene. One hundred and twenty one subjects (71.6%) were H. pylori positive. The cagA gene and more toxigenic s1 and m1 alleles of the vacA gene were found in 61.2%, 76.9% and 45.5% respectively of Gambian patients harbouring H. pylori. There was a high prevalence of cagA positive strains in patients with overt gastric diseases than those with non-ulcerative dyspepsia (NUD) (p = 0.05); however, mixed infection by cagA positive and cagA negative strains was more common in patients with NUD compared to patients with gastric disease (24.5% versus 0%; p = 0.002). CONCLUSION: This study shows that the prevalence of H. pylori is high in dyspeptic patients in The Gambia and that many strains are of the putatively more virulent cagA+, vacAs1 and vacAm1 genotypes. This study has also shown significantly lower disease burden in Gambians infected with a mixture of cag-positive and cag-negative strains, relative to those containing only cag-positive or only cag-negative strains, which suggests that harbouring both cag-positive and cag-negative strains is protective.


Assuntos
Antígenos de Bactérias/metabolismo , Proteínas de Bactérias/metabolismo , Coinfecção/microbiologia , Infecções por Helicobacter/epidemiologia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Coinfecção/epidemiologia , Coinfecção/terapia , Efeitos Psicossociais da Doença , Gâmbia/epidemiologia , Genes Bacterianos/genética , Genótipo , Infecções por Helicobacter/terapia , Helicobacter pylori/genética , Humanos , Pessoa de Meia-Idade , Gastropatias/genética , Gastropatias/microbiologia , Resultado do Tratamento , Virulência/genética , Adulto Jovem
15.
Gut Pathog ; 3(1): 5, 2011 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-21507253

RESUMO

BACKGROUND: Helicobacter pylori is an important agent of gastroduodenal disease in Africa and throughout the world. We sought to determine an optimum method for genotyping H. pylori strains from children and adults in The Gambia, West Africa. RESULTS: Virulence genes were amplified in 127 of 190 cases tested (121 adults and 6 children); each of 60 bacterial cultures, and 116 from DNA extracted directly from biopsies. The proportion of biopsies that were cagA+, the ratio of vacAs1/s2, and vacAm1/m2, and the proportion of mixed strain populations in individual subjects changed with age. Strains lacking virulence cagA and vacA genes and with apparently homogeneous (one predominant strain) infections were more common among infants than adults. CONCLUSIONS: In order to detect the range of bacterial genotypes harbored by individual patients, direct PCR proved slightly superior to isolation of H. pylori by biopsy culture, but the techniques were complementary, and the combination of both culture and direct PCR produced the most complete picture. The seemingly higher virulence of strains from adult than infant infections in The Gambia merits further analysis.

16.
ACS Nano ; 5(5): 4104-11, 2011 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-21506567

RESUMO

A combined experimental and theoretical analysis of the charge transport through single-molecule junctions is performed to define the influence of molecular end groups for increasing electrode separation. For both amine-ended and thiol-ended octanes contacted to gold electrodes, we study signatures of chain formation by analyzing kinks in conductance traces, the junction length, and inelastic electron tunneling spectroscopy. The results show that for amine-ended molecular junctions no atomic chains are pulled under stretching, whereas the Au electrodes strongly deform for thiol-ended molecular junctions. This advanced approach hence provides unambiguous evidence that the amine anchors bind only weakly to Au.


Assuntos
Alcanos/química , Aminas/química , Microscopia de Tunelamento/métodos , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Compostos de Sulfidrila/química , Módulo de Elasticidade , Transporte de Elétrons , Teste de Materiais , Tamanho da Partícula , Semicondutores
17.
Theor Appl Genet ; 122(1): 143-9, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20725713

RESUMO

Stem rust (caused by Puccinia graminis Pers.:Pers. f. sp. tritici Eriks. & E. Henn.) has re-emerged as a threat to wheat production with the evolution of new pathogen races, namely TTKSK (Ug99) and its variants, in Africa. Deployment of resistant wheat cultivars has provided long-term control of stem rust. Identification of new resistance genes will contribute to future cultivars with broad resistance to stem rust. The related Canadian cultivars Peace and AC Cadillac show resistance to Ug99 at the seedling stage and in the field. The purpose of this study was to elucidate the inheritance and genetically map resistance to Ug99 in these two cultivars. Two populations were produced, an F(2:3) population from LMPG/AC Cadillac and a doubled haploid (DH) population from RL6071/Peace. Both populations showed segregation at the seedling stage for a single stem rust resistance (Sr) gene, temporarily named SrCad. SrCad was mapped to chromosome 6DS in both populations with microsatellite markers and a marker (FSD_RSA) that is tightly linked to the common bunt resistance gene Bt10. FSD_RSA was the closest marker to SrCad (≈ 1.6 cM). Evaluation of the RL6071/Peace DH population and a second DH population, AC Karma/87E03-S2B1, in Kenya showed that the combination of SrCad and leaf rust resistance gene Lr34 provided a high level of resistance to Ug99-type races in the field, whereas in the absence of Lr34 SrCad conferred moderate resistance. A survey confirmed that SrCad is the basis for all of the seedling resistance to Ug99 in Canadian wheat cultivars. While further study is needed to determine the relationship between SrCad and other Sr genes on chromosome 6DS, SrCad represents a valuable genetic resource for producing stem rust resistant wheat cultivars.


Assuntos
Basidiomycota/fisiologia , Mapeamento Cromossômico/métodos , Imunidade Inata/genética , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Plântula/genética , Triticum/genética , Canadá , Cruzamentos Genéticos , Genes de Plantas/genética , Marcadores Genéticos , Genótipo , Plântula/microbiologia , Triticum/imunologia , Triticum/microbiologia
18.
Theor Appl Genet ; 121(6): 1083-91, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20552325

RESUMO

Adult plant resistance (APR) to leaf rust and stripe rust derived from the wheat (Triticum aestivum L.) line PI250413 was previously identified in RL6077 (=Thatcher*6/PI250413). The leaf rust resistance gene in RL6077 is phenotypically similar to Lr34 which is located on chromosome 7D. It was previously hypothesized that the gene in RL6077 could be Lr34 translocated to another chromosome. Hybrids between RL6077 and Thatcher and between RL6077 and 7DS and 7DL ditelocentric stocks were examined for first meiotic metaphase pairing. RL6077 formed chain quadrivalents and trivalents relative to Thatcher and Chinese Spring; however both 7D telocentrics paired only as heteromorphic bivalents and never with the multivalents. Thus, chromosome 7D is not involved in any translocation carried by RL6077. A genome-wide scan of SSR markers detected an introgression from chromosome 4D of PI250413 transferred to RL6077 through five cycles of backcrossing to Thatcher. Haplotype analysis of lines from crosses of Thatcher × RL6077 and RL6058 (Thatcher*6/PI58548) × RL6077 showed highly significant associations between introgressed markers (including SSR marker cfd71) and leaf rust resistance. In a separate RL6077-derived population, APR to stripe rust was also tightly linked with cfd71 on chromosome 4DL. An allele survey of linked SSR markers cfd71 and cfd23 on a set of 247 wheat lines from diverse origins indicated that these markers can be used to select for the donor segment in most wheat backgrounds. Comparison of RL6077 with Thatcher in field trials showed no effect of the APR gene on important agronomic or quality traits. Since no other known Lr genes exist on chromosome 4DL, the APR gene in RL6077 has been assigned the name Lr67.


Assuntos
Basidiomycota/genética , Cromossomos de Plantas/genética , Genes de Plantas , Folhas de Planta/genética , Triticum/genética , Alelos , Basidiomycota/imunologia , Marcadores Genéticos , Haplótipos , Hibridização Genética , Imunidade Inata , Repetições Minissatélites/genética , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Plantas/genética , Plantas/imunologia , Triticum/imunologia
19.
Theor Appl Genet ; 119(3): 541-53, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19471904

RESUMO

Common bunt, caused by Tilletia caries (DC.) Tul. & C. Tul. and T. laevis J.G Kuhn, is an economically important disease of wheat (Triticum aestivum L.) worldwide. The resistance in the winter wheat cultivar 'Blizzard' is effective against known races of common bunt in western Canada. The incorporation of resistance from Blizzard into field-ready cultivars may be accelerated through the use of molecular markers. Using the maize pollen method, a doubled haploid population of 147 lines was developed from the F(1) of the second backcross of Blizzard (resistant) by breeding line '8405-JC3C' (susceptible). Doubled haploid lines were inoculated at seeding with race T19 or T19 and L16 and disease reaction was examined under controlled conditions in 1999 and natural conditions in 2002, and 2003. Resistant:susceptible-doubled haploid lines segregated in a 1:1 ratio for bunt reaction, indicating single major gene segregation. Microsatellite primers polymorphic on the parents were screened on the population. Initial qualitative segregation analysis indicated that the wheat microsatellite markers Xgwm374, Xbarc128 and Xgwm264, located on wheat chromosome 1BS, were significantly linked to the resistance locus. Qualitative results were confirmed with quantitative trait locus analysis. The genetic distance, calculated with JoinMap, between the bunt resistance locus and overlapping markers Xgwm374, Xgwm264 and Xbarc128 was 3.9 cM. The three markers were validated on doubled haploid populations BW337/P9502&DAF1BB and Blizzard/P9514-AR17A3E evaluated for common bunt reaction in the growth chamber in 2007. These markers will be useful in selecting for the common bunt resistance from Blizzard and assist in identifying the resistance among potential new sources of resistance.


Assuntos
Cromossomos de Plantas , Genes de Plantas , Marcadores Genéticos , Doenças das Plantas/genética , Triticum/genética , Mapeamento Cromossômico , Cruzamentos Genéticos , DNA de Plantas/genética , DNA de Plantas/isolamento & purificação , Haploidia , Imunidade Inata , Repetições de Microssatélites , Polimorfismo Genético , Locos de Características Quantitativas , Reprodutibilidade dos Testes
20.
Public Health Nutr ; 12(10): 1862-70, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19257919

RESUMO

OBJECTIVE: To investigate the association between Helicobacter pylori infection and anaemia. DESIGN: Six cross-sectional studies. H. pylori infection was assessed by the [13C]urea breath test using MS or IR analysis. Hb was measured for all countries. Ferritin and transferrin receptors were measured for Argentina, Bolivia, Mexico, and Venezuela. SETTING: Health services in Argentina, Brazil and Mexico or public schools in Bolivia, Cuba and Venezuela. SUBJECTS: In Argentina, 307 children aged 4-17 years referred to a gastroenterology unit; in Bolivia, 424 randomly selected schoolchildren aged 5-8 years; in Brazil, 1007 adults (157 men, 850 women) aged 18-45 years attending thirty-one primary health-care units; in Cuba, 996 randomly selected schoolchildren aged 6-14 years; in Mexico, seventy-one pregnant women in their first trimester attending public health clinics; in Venezuela, 418 children aged 4-13 years attending public schools. RESULTS: The lowest prevalence of H. pylori found was among children in Argentina (25.1%) and the highest in Bolivia (74.0%). In Bolivia, Cuba and Venezuela children showed similar prevalence of H. pylori infection as in Brazilian and Mexican adults (range 47.5% to 81.8%). Overall anaemia prevalence was 11.3% in Argentina, 15.4% in Bolivia, 20.6% in Brazil, 10.5% in Cuba and 8.9% in Venezuela. Adjusted analyses allowing for confounding variables showed no association between H. pylori colonization and anaemia in any study. Hb, ferritin and transferrin receptor levels were also not associated with H. pylori infection in any country. CONCLUSIONS: The present study showed no evidence to support the hypothesis that H. pylori contributes to anaemia in children, adolescents, adults or pregnant women in six Latin American countries.


Assuntos
Anemia/etiologia , Infecções por Helicobacter/complicações , Helicobacter pylori , Adolescente , Adulto , Anemia/epidemiologia , Criança , Pré-Escolar , Fatores de Confusão (Epidemiologia) , Estudos Transversais , Cuba/epidemiologia , Feminino , Ferritinas/sangue , Infecções por Helicobacter/epidemiologia , Humanos , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Razão de Chances , Gravidez , Prevalência , América do Sul/epidemiologia , Adulto Jovem
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