RESUMO
Beef colour is essential to consumer acceptability with dark muscle colours being problematic. Dark meat has less light scattering but the mechanisms are unknown. We hypothesise that three mechanisms are responsible for decreased light scattering in dark meat, namely (i) larger lateral separation of myofilaments, (ii) decreased optical protein density in the I-band and (iii) decreased denaturation of sarcoplasmic proteins. Nineteen beef longissimus thoracis muscles, divided into 'light', 'medium' and 'dark' colour groups, were assessed for light scattering by reflectance confocal microscopy, sarcomere length, and myofilament lattice spacing by small-angle X-ray diffraction. Dark muscles had a longer lattice spacing, shorter sarcomeres and wider muscle fibre diameters compared to lighter colour groups, indicating that the transverse spacing of muscle fibres that occurs post-mortem, with pH decline, is central to light scattering development. Dark muscles also had more degradation of the Z-disc and higher sarcoplasmic protein activities, which could impact on the optical density and contribute to lower light scattering.
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Cor , Fibras Musculares Esqueléticas/ultraestrutura , Músculo Esquelético/citologia , Miofibrilas , Carne Vermelha/análise , Animais , Bovinos , Luz , Microscopia Confocal/métodos , Músculo Esquelético/anatomia & histologia , Sarcômeros , Difração de Raios X/métodosRESUMO
Beef meat colour is impacted by both myoglobin status and the light scattering properties of the muscle, and the specific causative scattering elements of the latter are still unknown. We hypothesize that stretching muscles during rigor will generate a structure which favours light scattering, by increasing the length of the I-band (longer sarcomeres) and that a high rigor temperature will cause protein reconfiguration, changing the muscle structure and promoting light scattering. Muscle fibre fragments were isolated from four beef M. sternomandibularis and subjected to stretching (plus, minus) and three incubation temperatures (5, 15, 35⯰C). Reflectance confocal laser scanning microscopy (rCLSM) revealed sarcomere stretching alone was not solely responsible for light scattering development. A high rigor temperature (35⯰C) was more favourable for light scattering. Stretching and taking muscle into rigor at 35⯰C promoted transverse shrinkage of muscle fibres and increased light scattering and could be applied post-mortem (PM) to reduce the occurrence of problematic dark meat.
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Cor , Manipulação de Alimentos/métodos , Temperatura Alta , Proteínas Musculares/química , Músculo Esquelético , Carne Vermelha/análise , Sarcômeros , Animais , Bovinos , Feminino , Humanos , Luz , Microscopia Confocal/métodos , Fibras Musculares Esqueléticas/ultraestrutura , Músculo Esquelético/citologia , Músculo Esquelético/ultraestrutura , Desnaturação Proteica , Rigor MortisRESUMO
Most studies have focused on myoglobin regarding meat colour development, with little focus on the contribution of muscle structure and light scattering. Our aim was to investigate the pH-dependent changes in muscle structure, on the light scattering properties of the meat. Beef longissimus thoracis muscles were segregated into light, medium or dark colour groups (n=18). 'Dark' muscles had a high ultimate pH (pHu), lower lightness (L*), redness (a*), higher myoglobin concentration and deoxymyoglobin content compared to other muscles. Reflectance confocal laser scanning microscopy (rCLSM) revealed 'dark' muscles had decreased global brightness (indicator of light scattering) and increased fibre width. In a secondary experiment, decreasing the homogenisation buffer pH from 6.10 to 5.40 induced a 17% shrinkage in high pHu muscle fibres, which increased light scattering by ~25%. In conclusion, rCLSM demonstrated that muscle structure contributes to the magnitude of light scattering by a pH dependent mechanism.
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Fibras Musculares Esqueléticas/citologia , Músculos Paraespinais/química , Músculos Paraespinais/citologia , Carne Vermelha/análise , Animais , Bovinos , Cor , Concentração de Íons de Hidrogênio , Microscopia Confocal , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/citologia , MioglobinaRESUMO
This study demonstrates the effect of active pharmaceutical ingredient (API) particle habit on the sticking propensity of ibuprofen. Four diverse crystal habits with similar physico chemical properties are reported and the sticking propensity was found to increase with shape regularity. The surface energy of the extreme habits were shown to be different where particles that were more regular in shape exhibited surface energies of 9mJ/m2 higher than those that were needle-like in habit. Computational and experimental data reveals that the increase in surface energy of the regular shaped particles can be attributed to the increase in the specific (polar) component, which is due to greater presence of faces which contain the carboxylic acid functionality at the surface. The increase in the specific energy component is shown to correlate with the sticking propensity of ibuprofen. It is proposed that investigation of the chemical causality of sticking, for this API and others, using the techniques demonstrated in this paper will be of increasing importance.
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Ibuprofeno/análise , Química Farmacêutica , Tamanho da Partícula , Propriedades de Superfície , ComprimidosRESUMO
OBJECTIVES: To assess Former Persons Under Monitoring (FPUM)s' experiences and perceptions of the United States (US) Ebola Active Monitoring Program. STUDY DESIGN: Retrospective assessment survey of FPUM. METHODS: An electronic survey was distributed to FPUMs monitored in Washington, DC, during October 2014-September 2015 (n = 830). RESULTS: Most FPUMs (>70%) had a favourable perception of the program. Less than 5% avoided future travel or participation in outbreak response activities as a result of their monitoring experience. Approximately 29% experienced a negative consequence in the US due to their travel history. Only 19.2% reported that the Check and Report Ebola (CARE) phone was their only means of communication and 56.5% never used it for daily reporting. Experiences and perceptions varied significantly by citizenship with citizens of Ebola-affected countries more likely to have a favourable perception of the program, use CARE phones and express concern about Ebola transmission and development. CONCLUSIONS: FPUMs perceived the program as beneficial and undergoing monitoring was not a barrier to future travel. Negative consequences resulting from travel were frequent. Targeted distribution of resources (e.g. CARE phones) should be considered for future programs.
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Surtos de Doenças/prevenção & controle , Doença pelo Vírus Ebola/prevenção & controle , Vigilância da População/métodos , Viagem , África Ocidental/epidemiologia , District of Columbia , Doença pelo Vírus Ebola/epidemiologia , Humanos , Avaliação de Programas e Projetos de Saúde , Estudos Retrospectivos , Inquéritos e QuestionáriosRESUMO
A wide variety of herbal remedies are used in traditional Australian medicine to treat inflammatory disorders, including autoimmune inflammatory diseases. One hundred and six extracts from 40 native Australian plant species traditionally used for the treatment of inflammation and/or to inhibit bacterial growth were investigated for their ability to inhibit the growth of a microbial trigger for ankylosing spondylitis (K. pneumoniae). Eighty-six of the extracts (81.1%) inhibited the growth of K. pneumoniae. The D. leichardtii, Eucalyptus spp., K. flavescens, Leptospermum spp., M. quinquenervia, Petalostigma spp., P. angustifolium, S. spinescens, S. australe, S. forte and Tasmannia spp. extracts were effective K. pneumoniae growth inhibitors, with MIC values generally <1000 µg/mL. The T. lanceolata peppercorn extracts were the most potent growth inhibitors, with MIC values as low as 16 µg/mL. These extracts were examined by non-biased GC-MS headspace analysis and comparison with a compound database. A notable feature was the high relative abundance of the sesquiterpenoids polygodial, guaiol and caryophyllene oxide, and the monoterpenoids linalool, cineole and α-terpineol in the T. lanceolata peppercorn methanolic and aqueous extracts. The extracts with the most potent K. pneumoniae inhibitory activity (including the T. lanceolata peppercorn extracts) were nontoxic in the Artemia nauplii bioassay. The lack of toxicity and the growth inhibitory activity of these extracts against K. pneumoniae indicate their potential for both preventing the onset of ankylosing spondylitis and minimising its symptoms once the disease is established.
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Gerenciamento Clínico , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/crescimento & desenvolvimento , Extratos Vegetais/farmacologia , Plantas Medicinais , Espondilite Anquilosante , Austrália , Humanos , Testes de Sensibilidade Microbiana , Componentes Aéreos da Planta , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/uso terapêutico , Espondilite Anquilosante/tratamento farmacológico , Espondilite Anquilosante/epidemiologia , Espondilite Anquilosante/microbiologiaRESUMO
Some patients suffering from the same neuropsychiatric disorder may have no overlapping symptoms whilst others may share symptoms common to other distinct disorders. Therefore, the Research Domain Criteria initiative recognises the need for better characterisation of the individual symptoms on which to focus symptom-based treatment strategies. Many of the disorders involve dysfunction within the prefrontal cortex (PFC) and so the marmoset, due to their highly developed PFC and small size, is an ideal species for studying the neurobiological basis of the behavioural dimensions that underlie these symptoms.Here we focus on a battery of tests that address dysfunction spanning the cognitive (cognitive inflexibility and working memory), negative valence (fear generalisation and negative bias) and positive valence (anhedonia) systems pertinent for understanding disorders such as ADHD, Schizophrenia, Anxiety, Depression and OCD. Parsing the separable prefrontal and striatal circuits and identifying the selective neurochemical modulation (serotonin vs dopamine) that underlie cognitive dysfunction have revealed counterparts in the clinical domain. Aspects of the negative valence system have been explored both at individual- (trait anxiety and genetic variation in serotonin transporter) and circuit-based levels enabling the understanding of generalisation processes, negative biases and differential responsiveness to SSRIs. Within the positive valence system, the combination of cardiovascular and behavioural measures provides a framework for understanding motivational, anticipatory and consummatory aspects of anhedonia and their neurobiological mechanisms. Together, the direct comparison of experimental findings in marmosets with clinical studies is proving an excellent translational model to address the behavioural dimensions and neurobiology of neuropsychiatric symptoms. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 328-353, 2017.
Assuntos
Sintomas Afetivos/fisiopatologia , Anedonia/fisiologia , Callithrix/fisiologia , Disfunção Cognitiva/fisiopatologia , Modelos Animais de Doenças , Medo/fisiologia , Transtornos Mentais/fisiopatologia , Córtex Pré-Frontal/fisiopatologia , Sintomas Afetivos/metabolismo , Animais , Disfunção Cognitiva/metabolismo , Humanos , Transtornos Mentais/metabolismo , Córtex Pré-Frontal/metabolismoRESUMO
Genetic control of resistance to Fusarium head blight (FHB) is quantitative, making phenotypic selection difficult. Genetic markers to resistance are helpful to select favorable genotypes. This study was conducted to determine if Fhb1 and Fhb5 present in the Sumai 3 source of FHB resistance occur in Sumai 3-derived North American spring wheat cultivars and to understand the appropriateness of using markers to select for the favorable alleles at these loci in breeding. Sumai 3-derived parents Alsen, ND3085, ND744, Carberry, and Glenn were used in crosses to generate 14 doubled haploid breeding populations. The parents and progeny were genotyped with five Fhb1 and three Fhb5 microsatellite markers. Progeny were selected based on performance relative to parents and other control cultivars in FHB nurseries near Portage la Prairie and Carman, MB. χ2 and t test analyses were performed on marker and FHB data. The χ2 test frequently determined the proportion of lines carrying molecular variants associated with FHB resistance increased following nursery selection for FHB. Similarly, the t test regularly demonstrated that selection for FHB resistance lowered the mean level of disease associated with resistant marker haplotypes. The study affirmed FHB resistance sources Alsen, Carberry, ND3085, and ND744 have Fhb1 and Fhb5 loci like Sumai 3, but no evidence was found that Glenn carries Fhb1 and Fhb5 resistance alleles. The results justified use of Fhb1 and Fhb5 markers for marker assisted selection in populations derived from Alsen, Carberry, ND3085, and ND744, but not Glenn. Combined or individual application of Xgwm493 and Xgwm533 in selection of genotypes carrying Fhb1, and Xgwm150, Xgwm304, and Xgwm595 for Fhb5 will enhance FHB resistance in wheat.
RESUMO
Purpose/objectives The aims of this study were to describe the development of a novel e-learning resource and to assess its impact on student learning experiences and orthodontic knowledge.Methods Thirty-two 4th year dental undergraduate students at Queen Mary University of London were randomly allocated to receive electronic access to e-learning material covering various undergraduate orthodontic topics over a 6-week period. Thirty-one control students were not given access during the study period. All students were asked to complete electronic quizzes both before (T0) and after (T1) the study period and a general questionnaire concerning familiarity with e-learning. The test group also completed a user satisfaction questionnaire at T1. Two focus groups were also undertaken to explore learners' experiences and suggestions in relation to the resource.Results The mean quiz result improved by 3.9% and 4.5% in the control and test groups, respectively. An independent t-test, however, demonstrated a lack of statistical significance in knowledge gain between control and test groups (P = 0.941). The qualitative feedback indicated that students believed that use of the resource enhanced knowledge and basic understanding with students expressing a wish to ingrain similar resources in other areas of undergraduate teaching.Conclusions Use of the novel orthodontic e-resource by 4th year undergraduate students over a 6-week period did not result in a significant improvement in subject knowledge. However, the e-learning has proven popular among undergraduates and the resources will continue to be refined.
Assuntos
Educação em Odontologia , Educação a Distância , Internet , Estudantes de Odontologia , Retroalimentação , Grupos Focais , Humanos , AprendizagemRESUMO
Severe losses attributable to pre-harvest sprouting (PHS) have been reported in Canada in recent years. The genetics of PHS resistance have been more extensively studied in hexaploid wheat and generally not using combinations of elite agronomic parents. The objective of our research was to understand the genetic nature of PHS resistance in an elite durum cross. A doubled haploid (DH) population and checks were phenotyped in replicated trials for grain yield and PHS traits over 3 years in western Canada. The response of intact spikes to sprouting conditions, sampled over two development time points, was measured in a rain simulation chamber. The DH population was genotyped with simple sequence repeat and Diversity Arrays Technology markers. Genotypes were a significant source of variation for grain yield and PHS resistance traits in each tested environment. Transgressive segregant DH genotypes were identified for grain yield and PHS resistance measurements. Low or no correlation was detected between grain yield and PHS, while correlation between PHS resistance measurements was moderate. The heritability of PHS resistance was moderate and higher than grain yield. Significant quantitative trait loci with small effect were detected on chromosomes 1A, 1B, 5B, 7A and 7B. Both parents contributed to the PHS resistance. Promising DH genotypes with high and stable grain yield as well as PHS resistance were identified, suggesting that grain yield and PHS can be improved simultaneously in elite genetic materials, and that these DH genotypes will be useful parental material for durum breeding programs.
RESUMO
PURPOSE: To analyze the frequency, rationale and determinants of attending physicians requesting that their eligible patients not be approached for participation in a thromboprophylaxis trial. METHODS: Research personnel in 67 centers prospectively documented eligible non-randomized patients due to physicians declining to allow their patients to be approached. RESULTS: In 67 centers, 3,764 patients were enrolled, but 1,460 eligible patients had no consent encounter. For 218 (14.9 %) of these, attending physicians requested that their patients not be approached. The most common reasons included a high risk of bleeding (31.2 %) related to fear of heparin bioaccumulation in renal failure, the presence of an epidural catheter, peri-operative status or other factors; specific preferences for thromboprophylaxis (12.4 %); morbid obesity (9.6 %); uncertain prognosis (6.4 %); general discomfort with research (3.7 %) and unclear reasons (17.0 %). Physicians were more likely to decline when approached by less experienced research personnel; considering those with[10 years of experience as the reference category, the odds ratios (OR) for physician refusals to personnel without trial experience was 10.47 [95 % confidence interval (CI) 2.19-50.02] and those with less than 10 years experience was 1.72 (95 % CI 0.61-4.84). Physicians in open rather than closed units were more likely to decline (OR 4.26; 95 % CI 1.27-14.34). Refusals decreased each year of enrollment compared to the pilot phase. CONCLUSIONS: Tracking, analyzing, interpreting and reporting the rates and reasons for physicians declining to allow their patients to be approached for enrollment provides insights into clinicians' concerns and attitudes to trials. This information can encourage physician communication and education, and potentially enhance efficient recruitment.
Assuntos
Cuidados Críticos/psicologia , Fibrinolíticos/uso terapêutico , Consentimento Livre e Esclarecido/psicologia , Médicos/psicologia , Recusa de Participação/psicologia , Trombose/prevenção & controle , Dalteparina/efeitos adversos , Dalteparina/uso terapêutico , Método Duplo-Cego , Fibrinolíticos/efeitos adversos , Heparina/administração & dosagem , Heparina/uso terapêutico , Humanos , Unidades de Terapia Intensiva , Participação do Paciente , Seleção de Pacientes , Padrões de Prática Médica , Estudos ProspectivosRESUMO
Stem rust (Puccinia graminis f. sp. tritici) is responsible for major production losses in hexaploid wheat (Triticum aestivum L.) around the world. The spread of stem rust race Ug99 and variants is a threat to worldwide wheat production and efforts are ongoing to identify and incorporate resistance. The objectives of this research were to identify quantitative trait loci (QTL) and to study their epistatic interactions for stem rust resistance in a population derived from the Canadian wheat cultivars AC Cadillac and Carberry. A doubled haploid (DH) population was developed and genotyped with DArT(®) and SSR markers. The parents and DH lines were phenotyped for stem rust severity and infection response to Ug99 and variant races in 2009, 2010 and 2011 in field rust nurseries near Njoro, Kenya, and to North American races in 2011 and 2012 near Swift Current, SK, Canada. Seedling infection type to race TTKSK was assessed in a bio-containment facility in 2009 and 2012 near Morden, MB. Eight QTL for stem rust resistance and three QTL for pseudo-black chaff on nine wheat chromosomes were identified. The phenotypic variance (PV) explained by the stem rust resistance QTL ranged from 2.4 to 48.8 %. AC Cadillac contributed stem rust resistance QTL on chromosomes 2B, 3B, 5B, 6D, 7B and 7D. Carberry contributed resistance QTL on 4B and 5A. Epistatic interactions were observed between loci on 4B and 5B, 4B and 7B, 6D and 3B, 6D and 5B, and 6D and 7B. The stem rust resistance locus on 6D interacted synergistically with 5B to improve the disease resistance through both crossover and non-crossover interactions depending on the environment. Results from this study will assist in planning breeding for stem rust resistance by maximizing QTL main effects and epistatic interactions.
Assuntos
Resistência à Doença/genética , Doenças das Plantas/imunologia , Locos de Características Quantitativas/genética , Triticum/genética , Basidiomycota , Mapeamento Cromossômico , Cromossomos de Plantas , Grão Comestível/genética , Epistasia Genética , Genótipo , Doenças das Plantas/microbiologia , Caules de Planta , Triticum/imunologia , Triticum/microbiologiaRESUMO
Leaf rust (Puccinia triticina Eriks.), stripe rust (Puccinia striiformis f. tritici Eriks.) and stem rust (Puccinia graminis f. sp. tritici) cause major production losses in durum wheat (Triticum turgidum L. var. durum). The objective of this research was to identify and map leaf, stripe and stem rust resistance loci from the French cultivar Sachem and Canadian cultivar Strongfield. A doubled haploid population from Sachem/Strongfield and parents were phenotyped for seedling reaction to leaf rust races BBG/BN and BBG/BP and adult plant response was determined in three field rust nurseries near El Batan, Obregon and Toluca, Mexico. Stripe rust response was recorded in 2009 and 2011 nurseries near Toluca and near Njoro, Kenya in 2010. Response to stem rust was recorded in field nurseries near Njoro, Kenya, in 2010 and 2011. Sachem was resistant to leaf, stripe and stem rust. A major leaf rust quantitative trait locus (QTL) was identified on chromosome 7B at Xgwm146 in Sachem. In the same region on 7B, a stripe rust QTL was identified in Strongfield. Leaf and stripe rust QTL around DArT marker wPt3451 were identified on chromosome 1B. On chromosome 2B, a significant leaf rust QTL was detected conferred by Strongfield, and at the same QTL, a Yr gene derived from Sachem conferred resistance. Significant stem rust resistance QTL were detected on chromosome 4B. Consistent interactions among loci for resistance to each rust type across nurseries were detected, especially for leaf rust QTL on 7B. Sachem and Strongfield offer useful sources of rust resistance genes for durum rust breeding.
RESUMO
Video analysis has become a useful tool in the preparation for sport performance and its use has highlighted the different physiological demands of seemingly similar sports and playing positions. The aim of the current study was to examine the performance differences between classical ballet and contemporary dance. In total 93 dance performances (48 ballet and 45 contemporary) were analysed for exercise intensity, changes in direction and specific discrete skills (e. g., jumps, lifts). Results revealed significant differences between the 2 dance forms for exercise intensity (p<0.001), changes in direction (p<0.001) and discrete skills (p<0.05) with gender differences noted in the latter (p<0.05). Ballet was characterised by longer periods at rest (38 s x min(-1)) and high to very high exercise intensities (9 s x min(-1)), whilst contemporary dance featured more continuous moderate exercise intensities (27 s x min(-1)). These differences have implications on the energy systems utilised during performance with ballet potentially stressing the anaerobic system more than contemporary dance. The observed high rates in the discrete skills in ballet (5 jumps x min(-1); 2 lifts x min(-1)) can cause local muscular damage, particularly in relatively weaker individuals. In conclusion, classical ballet and contemporary dance performances are as significantly different in the underlying physical demands placed on their performers as the artistic aspects of the choreography.
Assuntos
Desempenho Atlético/fisiologia , Dança/fisiologia , Exercício Físico/fisiologia , Gravação em Vídeo , Feminino , Humanos , Masculino , Músculo Esquelético/metabolismo , Fatores Sexuais , Estudos de Tempo e MovimentoRESUMO
Functional ankle instability (FAI) is a common condition following ankle injury characterised by increased risk of injury. Ankle sprains are a common acute form of injury suffered in dancing and loss of balance can affect not only risk of injury risk but also performance aesthetics. Whole body vibration training (WBVT) is a new rehabilitation method that has been linked with improving balance and muscle function. 38 female dancers with self reported unilateral FAI were randomly assigned in 2 groups: WBVT and control. Absolute centre of mass (COM) distribution during single leg stance, SEBT normalised research distances and Peroneus longus mean power frequency (f(med)) where measured pre and post 6-week intervention. There was a significant improvement in COM distribution over the 6 weeks from 1.05 ± 0.57 to 0.33 ± 0.42 cm² (P<0.05), and 4 of the 8 planes of direction in the SEBT Ant, Antlat, Med and Antmed from 77.5 ± 7.1 to 84.1 ± 5.8% (P<0.05) compared to control groups during the course of the 6 week training intervention. There was no evidence of improvement in peroneus longus (f(med)) over time (P=0.915) in either group. WBVT improved static balance and SEBT scores amongst dancers exhibiting ankle instability but did not affect peroneus longus muscle fatigue.
Assuntos
Terapia por Exercício/métodos , Instabilidade Articular/terapia , Entorses e Distensões/terapia , Vibração , Adolescente , Articulação do Tornozelo/patologia , Dança , Feminino , Humanos , Fadiga Muscular , Músculo Esquelético/metabolismo , Fatores de Tempo , Adulto JovemRESUMO
We investigated the associations between leg length and specific ballet movements in different skill groups. Volunteers were from an undergraduate dance programme (n=18), a pre-professional school (n=43) and from an elite classical ballet company (n=45). Individual data were collected for anthropometry, vertical jump, leg dexterity, and leg active and passive ROM. ANCOVA identified both main effects as significant with regard to vertical jump (gender P<0.001 and skill P=0.017); leg length was also identified as a significant covariate (P=0.023). Analysis of leg dexterity identified no significant effects with gender, skill or leg length. Active and passive range of motion noted gender (P=0.001) and skill (P<0.001) differences. Leg length was found to be negatively associated with both active and passive ROM (P=0.002). In conclusion, the present data highlight the diverse and conflicting effects of leg length on fundamental ballet skills. The longer legs that benefit vertical jump have a negative influence on range of motion and leg dexterity except for highly skilled dancers, who through skill, seem to have overcome the effects of some of these dichotomies.
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Dança/fisiologia , Perna (Membro)/anatomia & histologia , Amplitude de Movimento Articular/fisiologia , Adolescente , Adulto , Análise de Variância , Antropometria , Feminino , Humanos , Masculino , Fatores Sexuais , Adulto JovemRESUMO
Levels of the heavy metal cadmium (Cd) in food products are a food safety concern. Grain Cd is higher in durum (Triticum turgidum L. var. durum) than in common wheat, so reduction of Cd in durum grain is a priority of breeding programs. Previous research demonstrated that a single dominant gene, Cdu1, confers the low grain Cd phenotype, but the map location of the gene is not known. A doubled haploid population segregating for Cd concentration, developed from the cross of W9262-260D3 (a Kyle*2/Biodur inbred selection with low Cd uptake) and Kofa (high Cd uptake) and mapped with microsatellite markers, was used to locate Cdu1. Grain Cd concentration was determined by standard laboratory methods on field grain samples in 2000 and 2001. The Cd concentration segregated bimodally, allowing Cdu1 to be mapped qualitatively as well as quantitatively with quantitative trait locus analysis. The Cdu1 gene mapped to the long arm of chromosome 5B.
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Cádmio/metabolismo , Mapeamento Cromossômico/métodos , Cromossomos de Plantas/genética , Genes de Plantas/genética , Triticum/genética , Transporte Biológico , Marcadores Genéticos , Escore Lod , Locos de Características Quantitativas/genética , Sementes/metabolismo , Especificidade da Espécie , Triticum/classificação , Triticum/metabolismoRESUMO
Grain protein concentration (GPC) is one of the most important factors influencing pasta-making quality. Durum wheat (Triticum turgidum L. var durum) cultivars with high GPC produce pasta with increased tolerance to overcooking and greater cooked firmness. However, the large environmental effect on expression of GPC and the negative correlation with grain yield have slowed genetic improvement of this important trait. Understanding the genetics and identification of molecular markers associated with high GPC would aid durum wheat breeders in trait selection at earlier generations. The objectives of this study were to identify and validate molecular markers associated with quantitative trait loci (QTL) for elevated GPC in durum wheat. A genetic map was constructed using SSR and DArT markers in an F(1)-derived doubled haploid (DH) population derived from the cross DT695 x Strongfield. The GPC data were collected from replicated trials grown in six Canadian environments from 2002 to 2005. QTL associated with variation for GPC were identified on the group 1, 2, and 7 chromosomes and on 5B and 6B, but only QGpc.usw-B3 on 2B and QGpc.usw-A3 on 7A were expressed consistently in four and six environments, respectively. Positive alleles for GPC at these loci were contributed by the high-GPC parent Strongfield. The QGpc.usw-A3 QTL was validated in a second DH population, and depending on environment, selection for the Strongfield allele at barc108 resulted in +0.4% to +1.0% increase in GPC, with little effect on yield in most environments. Given the consistent expression pattern in multiple populations and environments, barc108 could be useful for marker-assisted selection for high GPC.
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Adaptação Fisiológica , Produtos Agrícolas/genética , Grão Comestível/genética , Proteínas de Plantas/metabolismo , Locos de Características Quantitativas , Triticum/genética , Canadá , Grão Comestível/metabolismo , Meio Ambiente , Marcadores Genéticos , Variação Genética , Escore Lod , Repetições Minissatélites , Fenótipo , Reprodutibilidade dos Testes , Triticum/metabolismoRESUMO
The yellow pigment (YP) of durum wheat (Triticum turgidum L. var durum) semolina is due in part to the presence of carotenoid pigments found in the endosperm and is an important end-use quality trait. Phytoene synthase (Psy) is considered a rate-limiting enzyme in the carotenoid biosynthetic pathway and in this study, three alleles of Psy1-A1 were sequenced from four durum wheat cultivars and a co-dominant marker was developed for genetic mapping. Psy1-A1 mapped to chromosome 7AL near Xwmc809 in three durum mapping populations and was significantly associated with a pigment quantitative trait loci (QTL) identified on that chromosome. A second QTL localized 25 cM proximal to Psy1-A1 in two populations, and the interaction between the two QTL was not significant. Consistent with QTL mapping data, the Psy1-A1o allele was associated with elevated pigment in a validation population comprising 93 diverse cultivars and breeding lines. These results confirm an earlier hypothesis that Psy1, and at least one additional gene in the distal region of 7AL, are associated with grain YP differences in durum wheat. The functional co-dominant marker developed in this study differentiates the Psy1-A1 alleles reported here and could be used as a target to enhance YP selection in durum wheat breeding programs.
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Alquil e Aril Transferases/genética , Alelos , Genes de Plantas , Pigmentação/genética , Triticum/genética , Sequência de Aminoácidos , Sequência de Bases , Mapeamento Cromossômico , Cromossomos de Plantas , Clonagem Molecular , Cruzamentos Genéticos , DNA Complementar/química , DNA de Plantas , Éxons , Marcadores Genéticos , Variação Genética , Geranil-Geranildifosfato Geranil-Geraniltransferase , Haploidia , Íntrons , Dados de Sequência Molecular , Fases de Leitura Aberta , Locos de Características Quantitativas , Recombinação Genética , Homologia de Sequência de AminoácidosRESUMO
Approximately 3000 birds, mainly passerines, caught in mist nets in the northern provinces of South Africa, were examined for ticks. A total of 178 ticks, belonging to 14 species, were recovered from 83 birds of 43 different species. Hyalomma rufipes was the most numerous tick, with 26 larvae and 109 nymphs collected, followed by Amblyomma marmoreum, with 13 larvae and two nymphs. Despite the study being conducted within the distribution range of Amblyomma hebraeum, it was not seen on any passerines, whereas three larger species were infested. The potential for small birds to spread ticks with their associated tick-borne pathogens is discussed.