Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 78
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
J Nutr ; 154(2): 469-478, 2024 02.
Artículo en Inglés | MEDLINE | ID: mdl-38048992

RESUMEN

BACKGROUND: Aging and vitamin D deficiency have been associated with reduced nitric oxide (NO) synthesis and impaired endothelial function (EF) but the evidence in humans remains weak. OBJECTIVES: Two independent cross-sectional studies were designed to evaluate the association between age, sex, and plasma vitamin D concentrations with physiological and biochemical biomarkers of NO synthesis and EF in young and older healthy participants (Study 1) and in overweight and obese postmenopausal females (Study 2). METHODS: In Study 1, 40 young (20-49 y) and older (50-75 y) males and females (10 participants per age and sex group) were included. Resting blood pressure and ear-to-finger peripheral pulse wave velocity (PWV) were measured. A stable-isotopic method was used to determine whole-body NO production. Plasma 25-hydroxyvitamin D (25(OH)D), nitrate, nitrite, and asymmetric dimethylarginine (ADMA) concentrations were determined. In Study 2, 80 older overweight and obese females (age 61.2 ± 6.2 y, body mass index 29.5 ± 4.4 kg/m2) were recruited. Postocclusion reactive hyperemia (PORH) and peripheral PWV were measured. Plasma concentrations of 25(OH)D, nitrate, cyclic guanosine monophosphate, 3-nitrotyrosine (3-NT), endothelin-1, vascular endothelial growth factor, and ADMA were determined. RESULTS: In Study 1, whole-body NO production was significantly greater in young compared with older participants (0.61 ± 0.30 µmol·h-1·kg-1 compared with 0.39 ± 0.10 µmol·h-1·kg-1, P = 0.01) but there was no evidence of a sex difference (P = 0.81). Plasma 25(OH)D concentration was not associated with PWV (r = 0.18, P = 0.28) or whole-body NO production (r = -0.20, P = 0.22). Plasma ADMA concentration was associated positively with age (r = 0.35, P = 0.03) and negatively with whole-body NO production (r = -0.33, P = 0.04). In Study 2, age was associated with lower PORH (r = -0.28, P = 0.02) and greater ADMA concentrations (r = 0.22, P = 0.04). Plasma 25(OH)D concentration was inversely associated with 3-NT concentrations (r = -0.31, P = 0.004). CONCLUSIONS: Older age was associated with lower whole-body NO production. Plasma vitamin D concentrations were not associated with NO production or markers of EF but showed a weak, significant correlation with oxidative stress in postmenopausal overweight females.


Asunto(s)
Óxido Nítrico , Deficiencia de Vitamina D , Humanos , Masculino , Femenino , Persona de Mediana Edad , Anciano , Sobrepeso , Nitratos , Estudios Transversales , Análisis de la Onda del Pulso , Factor A de Crecimiento Endotelial Vascular , Envejecimiento , Vitamina D , Obesidad , Vitaminas
2.
Br J Nutr ; 131(5): 901-910, 2024 03 14.
Artículo en Inglés | MEDLINE | ID: mdl-37877251

RESUMEN

There is a dearth of data on Se status in very old adults. The aims of this study were to assess Se status and its determinants in 85-year-olds living in the Northeast of England by measuring serum Se and selenoprotein P (SELENOP) concentrations and glutathione peroxidase 3 (GPx3) activity. A secondary aim was to examine the interrelationships between each of the biomarkers. In total, 757 participants (463 women, 293 men) from the Newcastle 85+ Study were included. Biomarker concentrations were compared with selected cut-offs (serum Se: suboptimal 70 µg/l and deficient 45 µg/l; SELENOP: suboptimal 4·5 mg/l and deficient 2·6 mg/l). Determinants were assessed using linear regressions, and interrelationships were assessed using restricted cubic splines. Median (inter-quartile range) concentrations of serum Se, SELENOP and of GPx3 activity were 53·6 (23·6) µg/l, 2·9 (1·9) mg/l and 142·1 (50·7) U/l, respectively. Eighty-two percentage and 83 % of participants had suboptimal serum Se (< 70 µg/l) and SELENOP (< 4·5 mg/l), and 31 % and 40 % of participants had deficient serum Se (< 45 µg/l) and SELENOP (< 2·6 mg/l), respectively. Protein intake was a significant determinant of Se status. Additional determinants of serum Se were sex, waist:hip ratio, self-rated health and disease, while sex, BMI and physical activity were determinants of GPx3 activity. There was a linear association between serum Se and SELENOP, and nonlinear associations between serum Se and GPx3 activity and between SELENOP and GPx3 activity. These findings indicate that most participants had suboptimal Se status to saturate circulating SELENOP.


Asunto(s)
Selenio , Masculino , Adulto , Humanos , Femenino , Selenoproteína P/metabolismo , Biomarcadores , Antioxidantes , Inglaterra , Glutatión Peroxidasa
3.
Mol Biol Evol ; 39(1)2022 01 07.
Artículo en Inglés | MEDLINE | ID: mdl-34662426

RESUMEN

Wolbachia are a genus of widespread bacterial endosymbionts in which some strains can hijack or manipulate arthropod host reproduction. Male killing is one such manipulation in which these maternally transmitted bacteria benefit surviving daughters in part by removing competition with the sons for scarce resources. Despite previous findings of interesting genome features of microbial sex ratio distorters, the population genomics of male-killers remain largely uncharacterized. Here, we uncover several unique features of the genome and population genomics of four Arizonan populations of a male-killing Wolbachia strain, wInn, that infects mushroom-feeding Drosophila innubila. We first compared the wInn genome with other closely related Wolbachia genomes of Drosophila hosts in terms of genome content and confirm that the wInn genome is largely similar in overall gene content to the wMel strain infecting D. melanogaster. However, it also contains many unique genes and repetitive genetic elements that indicate lateral gene transfers between wInn and non-Drosophila eukaryotes. We also find that, in line with literature precedent, genes in the Wolbachia prophage and Octomom regions are under positive selection. Of all the genes under positive selection, many also show evidence of recent horizontal transfer among Wolbachia symbiont genomes. These dynamics of selection and horizontal gene transfer across the genomes of several Wolbachia strains and diverse host species may be important underlying factors in Wolbachia's success as a male-killer of divergent host species.


Asunto(s)
Wolbachia , Animales , Drosophila/genética , Drosophila/microbiología , Drosophila melanogaster/genética , Transferencia de Gen Horizontal , Genoma , Masculino , Wolbachia/genética
4.
BMC Med ; 21(1): 81, 2023 03 14.
Artículo en Inglés | MEDLINE | ID: mdl-36915130

RESUMEN

BACKGROUND: The identification of effective dementia prevention strategies is a major public health priority, due to the enormous and growing societal cost of this condition. Consumption of a Mediterranean diet (MedDiet) has been proposed to reduce dementia risk. However, current evidence is inconclusive and is typically derived from small cohorts with limited dementia cases. Additionally, few studies have explored the interaction between diet and genetic risk of dementia. METHODS: We used Cox proportional hazard regression models to explore the associations between MedDiet adherence, defined using two different scores (Mediterranean Diet Adherence Screener [MEDAS] continuous and Mediterranean diet Pyramid [PYRAMID] scores), and incident all-cause dementia risk in 60,298 participants from UK Biobank, followed for an average 9.1 years. The interaction between diet and polygenic risk for dementia was also tested. RESULTS: Higher MedDiet adherence was associated with lower dementia risk (MEDAS continuous: HR = 0.77, 95% CI = 0.65-0.91; PYRAMID: HR = 0.86, 95% CI = 0.73-1.02 for highest versus lowest tertiles). There was no significant interaction between MedDiet adherence defined by the MEDAS continuous and PYRAMID scores and polygenic risk for dementia. CONCLUSIONS: Higher adherence to a MedDiet was associated with lower dementia risk, independent of genetic risk, underlining the importance of diet in dementia prevention interventions.


Asunto(s)
Demencia , Dieta Mediterránea , Humanos , Estudios Prospectivos , Predisposición Genética a la Enfermedad , Bancos de Muestras Biológicas , Demencia/epidemiología , Demencia/genética , Demencia/prevención & control , Reino Unido/epidemiología
5.
Br J Nutr ; 127(10): 1567-1587, 2022 05 28.
Artículo en Inglés | MEDLINE | ID: mdl-34284830

RESUMEN

A multi-disciplinary expert group met to discuss vitamin D deficiency in the UK and strategies for improving population intakes and status. Changes to UK Government advice since the 1st Rank Forum on Vitamin D (2009) were discussed, including rationale for setting a reference nutrient intake (10 µg/d; 400 IU/d) for adults and children (4+ years). Current UK data show inadequate intakes among all age groups and high prevalence of low vitamin D status among specific groups (e.g. pregnant women and adolescent males/females). Evidence of widespread deficiency within some minority ethnic groups, resulting in nutritional rickets (particularly among Black and South Asian infants), raised particular concern. Latest data indicate that UK population vitamin D intakes and status reamain relatively unchanged since Government recommendations changed in 2016. Vitamin D food fortification was discussed as a potential strategy to increase population intakes. Data from dose-response and dietary modelling studies indicate dairy products, bread, hens' eggs and some meats as potential fortification vehicles. Vitamin D3 appears more effective than vitamin D2 for raising serum 25-hydroxyvitamin D concentration, which has implications for choice of fortificant. Other considerations for successful fortification strategies include: (i) need for 'real-world' cost information for use in modelling work; (ii) supportive food legislation; (iii) improved consumer and health professional understanding of vitamin D's importance; (iv) clinical consequences of inadequate vitamin D status and (v) consistent communication of Government advice across health/social care professions, and via the food industry. These areas urgently require further research to enable universal improvement in vitamin D intakes and status in the UK population.


Asunto(s)
Distinciones y Premios , Administración Financiera , Adolescente , Animales , Pollos , Femenino , Alimentos Fortificados , Humanos , Masculino , Embarazo , Reino Unido/epidemiología , Vitamina D , Vitaminas
6.
PLoS Pathog ; 15(9): e1007936, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31504075

RESUMEN

Wolbachia are the most widespread maternally-transmitted bacteria in the animal kingdom. Their global spread in arthropods and varied impacts on animal physiology, evolution, and vector control are in part due to parasitic drive systems that enhance the fitness of infected females, the transmitting sex of Wolbachia. Male killing is one common drive mechanism wherein the sons of infected females are selectively killed. Despite decades of research, the gene(s) underlying Wolbachia-induced male killing remain unknown. Here using comparative genomic, transgenic, and cytological approaches in fruit flies, we identify a candidate gene in the eukaryotic association module of Wolbachia prophage WO, termed WO-mediated killing (wmk), which transgenically causes male-specific lethality during early embryogenesis and cytological defects typical of the pathology of male killing. The discovery of wmk establishes new hypotheses for the potential role of phage genes in sex-specific lethality, including the control of arthropod pests and vectors.


Asunto(s)
Profagos/genética , Profagos/patogenicidad , Wolbachia/patogenicidad , Wolbachia/virología , Animales , Animales Modificados Genéticamente , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/fisiología , Drosophila/embriología , Drosophila/microbiología , Drosophila/virología , Drosophila melanogaster/embriología , Drosophila melanogaster/microbiología , Drosophila melanogaster/virología , Femenino , Genes Letales , Genes Virales , Interacciones Microbiota-Huesped/genética , Interacciones Microbiota-Huesped/fisiología , Masculino , Profagos/fisiología , Razón de Masculinidad , Simbiosis/genética , Simbiosis/fisiología , Proteínas Virales/genética , Proteínas Virales/fisiología
7.
Mol Ecol ; 30(1): 83-99, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-33089581

RESUMEN

Over time, populations of species can expand, contract, fragment and become isolated, creating subpopulations that must adapt to local conditions. Understanding how species maintain variation after divergence as well as adapt to these changes in the face of gene flow is of great interest, especially as the current climate crisis has caused range shifts and frequent migrations for many species. Here, we characterize how a mycophageous fly species, Drosophila innubila, came to inhabit and adapt to its current range which includes mountain forests in south-western USA separated by large expanses of desert. Using population genomic data from more than 300 wild-caught individuals, we examine four populations to determine their population history in these mountain forests, looking for signatures of local adaptation. In this first extensive study, establishing D. innubila as a key genomic "Sky Island" model, we find D. innubila spread northwards during the previous glaciation period (30-100 KYA) and have recently expanded even further (0.2-2 KYA). D. innubila shows little evidence of population structure, consistent with a recent establishment and genetic variation maintained since before geographic stratification. We also find some signatures of recent selective sweeps in chorion proteins and population differentiation in antifungal immune genes suggesting differences in the environments to which flies are adapting. However, we find little support for long-term recurrent selection in these genes. In contrast, we find evidence of long-term recurrent positive selection in immune pathways such as the Toll signalling system and the Toll-regulated antimicrobial peptides.


Asunto(s)
Drosophila , Flujo Génico , Aclimatación , Adaptación Fisiológica/genética , Animales , Drosophila/genética , Variación Genética , Islas
8.
J Fish Dis ; 44(6): 823-835, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33277726

RESUMEN

Atypical Aeromonas salmonicida (aAs) is currently one of the most routinely recovered bacterial pathogens isolated during disease outbreaks in farmed cleaner fish, ballan wrasse (Labrus bergylta, Ascanius). Vibrionaceae family bacteria have also been isolated from ballan wrasse in Scotland. This study determined the infectivity, pathogenicity and virulence of aAs and Vibrionaceae isolates in juvenile farmed ballan wrasse (n = 50; approx. 2 g) using a bath challenge, and fish were monitored for a period of 16 days. Atypical As caused significant mortalities in contrast to Vibrionaceae isolates. Notably, differential virulence was observed between two aAs vapA type V strains at similar challenge doses. Diseased fish exhibited a systemic infection where aAs was detected in all analysed tissues (liver, spleen and kidney) by PCR and qPCR. Macroscopically, moribund and survivor fish exhibited hepatomegaly and splenomegaly. In moribund and surviving fish, histopathology showed granulomatous hepatitis with eosinophilic granular cells surrounding bacterial colonies and endocarditis along with splenic histiocytosis. This is the first report of a successful aAs bath challenge model for juvenile ballan wrasse which provides an important tool for future studies on vaccine efficacy and immunocompetence.


Asunto(s)
Aeromonas salmonicida/aislamiento & purificación , Susceptibilidad a Enfermedades/veterinaria , Peces , Forunculosis/diagnóstico , Infecciones por Bacterias Gramnegativas/veterinaria , Factores de Edad , Animales , Susceptibilidad a Enfermedades/microbiología , Forunculosis/microbiología , Infecciones por Bacterias Gramnegativas/diagnóstico , Infecciones por Bacterias Gramnegativas/microbiología , Escocia
9.
Mol Biol Evol ; 36(7): 1405-1417, 2019 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-30865231

RESUMEN

Pathogenic microbes can exert extraordinary evolutionary pressure on their hosts. They can spread rapidly and sicken or even kill their host to promote their own proliferation. Because of this strong selective pressure, immune genes are some of the fastest evolving genes across metazoans, as highlighted in mammals and insects. Drosophila melanogaster serves as a powerful model for studying host/pathogen evolution. While Drosophila melanogaster are frequently exposed to various pathogens, little is known about D. melanogaster's ecology, or if they are representative of other Drosophila species in terms of pathogen pressure. Here, we characterize the genome of Drosophila innubila, a mushroom-feeding species highly diverged from D. melanogaster and investigate the evolution of the immune system. We find substantial differences in the rates of evolution of immune pathways between D. innubila and D. melanogaster. Contrasting what was previously found for D. melanogaster, we find little evidence of rapid evolution of the antiviral RNAi genes and high rates of evolution in the Toll pathway. This suggests that, while immune genes tend to be rapidly evolving in most species, the specific genes that are fastest evolving may depend either on the pathogens faced by the host and/or divergence in the basic architecture of the host's immune system.


Asunto(s)
Evolución Biológica , Drosophila/genética , Drosophila/inmunología , Genoma de los Insectos , Selección Genética , Animales , Femenino , Masculino , Interferencia de ARN
10.
Eur J Nutr ; 59(5): 1909-1918, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31292749

RESUMEN

INTRODUCTION: Growth in the number of very old (≥ 85 years) adults will likely lead to increased prevalence of disability. Our aim was to determine the contribution of protein intake, and the interaction between protein intake and physical activity (PA), to the transition between disability states and to death in the very old using the Newcastle 85+ Study. METHODS: The analytic sample comprised of 717 older adults aged 85 years at baseline and living in the community. Protein intake was estimated with 2 × 24-h multiple pass recalls (24 h-MPR) at baseline. Disability was measured as difficulty performing 17 activities of daily living (ADL) at baseline, at 18, 36, and 60 months, and defined as having difficulties in one or more ADL. The contribution of protein intake [g/kg adjusted body weight/day (g/kg aBW/d)] to transition probabilities to and from disability, and to death over 5 years was examined by multi-state models adjusted for key health covariates. RESULTS: Participants were expected to spend 0.8 years (95% CI 0.6-1.0) disability-free and 2.8 years (95% CI 2.6-2.9) with disability between the ages 85 and 90 years. One unit increase in protein intake (g/kg aBW/d) halved the likelihood of incident disability (HR 0.44, 95% CI 0.24-0.83) but not for other transitions. Similar reductions in disability incidence were also found in individuals with protein intake ≥ 0.8 (HR 0.50, 95% CI 0.31-0.80) and ≥ 1 g/kg aBW/d (HR 0.49, 95% CI 0.33-0.73). Participants with high PA and protein intake ≥ 1 g/kg aBW/d were less likely to transition from disability-free to disability than those within the same PA level but with protein intake < 1 g/kg aBW/d (HR 0.45, 95% CI 0.28-0.72). CONCLUSION: Higher protein intake, especially in combination with higher physical activity, may delay the incidence of disability in very old adults.


Asunto(s)
Actividades Cotidianas , Personas con Discapacidad , Anciano , Anciano de 80 o más Años , Ejercicio Físico , Humanos
11.
Subcell Biochem ; 91: 453-476, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30888662

RESUMEN

Osteoporosis is a "skeletal disorder characterized by compromised bone strength predisposing a person to an increased risk of fracture" which, in light of demographic change, is becoming an increasing burden on health care worldwide. Increasing age and female gender are associated with the condition, although a wider range of clinical risk factors are being used increasingly to identify those at risk of osteoporosis and its most important sequelae, fracture.While osteoporosis and fracture have long been associated with women in the post-menopausal age, fracture incidence increases because of the ageing of our population. Interventions to abate the progression of osteoporosis and to prevent fractures must focus on the old and the very old. Evidence associating nutritional factors, particularly calcium and vitamin D are reviewed as are the association of falls risk with fracture and the potential for interventions to prevent falls. Finally, the assessment of frailty in the oldest old, associated sarcopenia and multi-morbidity are considered in the evaluation of fall and fracture risk and the management of osteoporosis in the ninth decade of life and beyond.


Asunto(s)
Envejecimiento/patología , Osteoporosis Posmenopáusica/patología , Accidentes por Caídas/prevención & control , Envejecimiento/efectos de los fármacos , Densidad Ósea/efectos de los fármacos , Calcio/metabolismo , Calcio/farmacología , Femenino , Fracturas Óseas/etiología , Fracturas Óseas/prevención & control , Humanos , Osteoporosis Posmenopáusica/complicaciones , Osteoporosis Posmenopáusica/etiología , Osteoporosis Posmenopáusica/prevención & control , Factores de Riesgo , Vitamina D/metabolismo , Vitamina D/farmacología
12.
Calcif Tissue Int ; 105(4): 383-391, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31338563

RESUMEN

Alterations in musculoskeletal health with advanced age contribute to sarcopenia and decline in bone mineral density (BMD) and bone strength. This decline may be modifiable via dietary supplementation. To test the hypothesis that a specific oral nutritional supplement can result in improvements in measures of bone health. Participants (n 380) were participants of the PROVIDE study, a 13-week, multicenter, randomized, controlled, double-blind, 2 parallel-group study among non-malnourished older participants (≥ 65 years) with sarcopenia [determined by Short Physical Performance Battery (SPPB; 0-12) scores between 4 and 9, and a low skeletal muscle mass index (SMI; skeletal muscle mass/BW × 100) ≤ 37% in men and ≤ 28% in women using bioelectric impedance analysis] Supplementation of a vitamin D, calcium and leucine-enriched whey protein drink that comprises a full range of micronutrients (active; 2/day) was compared with an iso-caloric control. Serum 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), biochemical markers of bone formation (osteocalcin; OC, procollagen type 1 amino-terminal propeptide; P1NP) and resorption (carboxy-terminal collagen crosslinks; CTX), insulin like growth factor 1 (IGF-1) and total-body BMD were analysed pre- and post-intervention. Serum 25(OH)D concentrations increased from 51.1 ± 22.9 nmol/L (mean ± SD) to 78.9 ± 21.1 nmol/L in the active group (p < 0.001 vs. control). Serum PTH showed a significant treatment difference (p < 0.001) with a decline in the active group, and increase in the control group. Serum IGF-1 increased in the active group (p < 0.001 vs. control). Serum CTX showed a greater decline in the active group (p = 0.001 vs. control). There were no significant differences in serum OC or P1NP between groups during the intervention. Total body BMD showed a small (0.02 g/cm2; ~ 2%) but significant increase in the active group after supplementation (p = 0.033 vs. control). Consuming a vitamin D, calcium and leucine-enriched whey protein supplement for 13 weeks improved 25(OH)D, suppressed PTH and had small but positive effects on BMD, indicative of improved bone health, in sarcopenic non-malnourished older adults.


Asunto(s)
Densidad Ósea/efectos de los fármacos , Calcio/farmacología , Leucina/farmacología , Vitamina D/farmacología , Proteína de Suero de Leche/farmacología , Anciano , Envejecimiento/fisiología , Densidad Ósea/fisiología , Huesos/efectos de los fármacos , Huesos/metabolismo , Calcio/metabolismo , Suplementos Dietéticos , Método Doble Ciego , Femenino , Humanos , Leucina/metabolismo , Masculino , Persona de Mediana Edad , Fuerza Muscular/efectos de los fármacos , Músculo Esquelético/fisiología , Vitamina D/metabolismo
13.
Br J Nutr ; 121(7): 763-772, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30638442

RESUMEN

The consumption of high-Ca, high-protein dairy foods (i.e. milk, cheese, yogurt) is advocated for bone health across the lifespan to reduce the risk of low-trauma fractures. However, to date, the anti-fracture efficacy of dairy food consumption has not been demonstrated in randomised controlled trials but inferred from cross-sectional and prospective studies. The anti-fracture efficacy of dairy food consumption is plausible, but testing this requires a robust study design to ensure outcomes are suitably answering this important public health question. The evidence of skeletal benefits of dairy food consumption is equivocal, not because it may not be efficacious but because the study design and execution are often inadequate. The key issues are compliance with dietary intervention, dropouts, sample sizes and most importantly lack of deficiency before intervention. Without careful appraisal of the design and execution of available studies, precarious interpretations of outcomes may be made from these poorly designed or executed studies, without consideration of how study design may be improved. Dairy food interventions in children are further hampered by heterogeneity in growth: in particular sex and maturity-related differences in the magnitude, timing, location and surface-specific site of bone accrual. Outcomes of studies combining children of different sexes and maturity status may be masked or exaggerated by these differences in growth, so inaccurate conclusions are drawn from results. Until these critical issues in study design are considered in future dairy food interventions, the anti-fracture efficacy of dairy food consumption may remain unknown and continue to be based on conjecture.


Asunto(s)
Desarrollo Óseo/fisiología , Productos Lácteos/análisis , Fracturas Óseas/prevención & control , Longevidad/fisiología , Proyectos de Investigación/normas , Estudios Transversales , Femenino , Humanos , Masculino , Estudios Prospectivos
14.
Subcell Biochem ; 90: 191-220, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30779011

RESUMEN

One hundred years has passed since the discovery of vitamin D as the active component of cod-liver oil which cured the bone disease rickets. Since then our knowledge of vitamin D has expanded tremendously and has included recognition of the importance of UV radiation as a source of the vitamin as well as the discovery of the vitamin as a nutrient, a pro-hormone and a potent steroid hormone with a major role in calcium and bone metabolism. In the last 25 years or so, the discovery of the vitamin D receptor in over 30 different body tissues together with the existence of the alpha-1-hydroxylase enzyme in these tissues provided evidence of a pleiotropic role of vitamin D outside its classical role in the skeleton. These important discoveries have provided the basis for the increasing interest in vitamin D in the context of nutritional requirements for health including the prevention of chronic diseases of ageing. The recent publication of the Dietary Reference Intake report on vitamin D and calcium by the North American Institute of Medicine (IOM) is the most comprehensive report to date on the basis for setting nutritional requirements for vitamin D. This chapter will summarize the nutritional aspects of vitamin D and discuss the changes in vitamin D metabolism and requirements with ageing. It will summarize key evidence on the relationship between vitamin D status and some of the main ageing related health outcomes including bone, muscle and cognitive health as well as survival focusing on the published literature in very-old adults (those >= 85 years of age).


Asunto(s)
Envejecimiento , Vitamina D , Envejecimiento/metabolismo , Calcio/metabolismo , Humanos , Necesidades Nutricionales , Vitamina D/metabolismo , Vitaminas/metabolismo
15.
PLoS Genet ; 12(3): e1005920, 2016 03.
Artículo en Inglés | MEDLINE | ID: mdl-26982327

RESUMEN

In a classic example of the invasion of a species by a selfish genetic element, the P-element was horizontally transferred from a distantly related species into Drosophila melanogaster. Despite causing 'hybrid dysgenesis', a syndrome of abnormal phenotypes that include sterility, the P-element spread globally in the course of a few decades in D. melanogaster. Until recently, its sister species, including D. simulans, remained P-element free. Here, we find a hybrid dysgenesis-like phenotype in the offspring of crosses between D. simulans strains collected in different years; a survey of 181 strains shows that around 20% of strains induce hybrid dysgenesis. Using genomic and transcriptomic data, we show that this dysgenesis-inducing phenotype is associated with the invasion of the P-element. To characterize this invasion temporally and geographically, we survey 631 D. simulans strains collected on three continents and over 27 years for the presence of the P-element. We find that the D. simulans P-element invasion occurred rapidly and nearly simultaneously in the regions surveyed, with strains containing P-elements being rare in 2006 and common by 2014. Importantly, as evidenced by their resistance to the hybrid dysgenesis phenotype, strains collected from the latter phase of this invasion have adapted to suppress the worst effects of the P-element.


Asunto(s)
Elementos Transponibles de ADN/genética , Drosophila simulans/genética , Evolución Molecular , Infertilidad/genética , Animales , Cruzamientos Genéticos , Drosophila melanogaster/genética , Hibridación Genética , Especies Introducidas , Fenotipo , Filogenia
16.
PLoS Genet ; 12(5): e1006058, 2016 05.
Artículo en Inglés | MEDLINE | ID: mdl-27166958

RESUMEN

[This corrects the article DOI: 10.1371/journal.pgen.1005920.].

17.
J Virol ; 91(22)2017 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-28814516

RESUMEN

Hosts and viruses are locked in an evolutionary arms race. Hosts are constantly evolving to suppress virulence and replication, while viruses, which are reliant on host machinery for survival and reproduction, develop counterstrategies to escape this immune defense. Viruses must also adapt to novel conditions while establishing themselves in a host species. Both processes provide strong selection for viral adaptation. Understanding adaptive evolution in insect viruses can help us to better understand adaptive evolution in general and is important due to the use of these viruses as biocontrol agents and for protecting ecologically or economically important species from outbreaks. Here we examine the molecular evolution of baculoviruses and nudiviruses, a group of insect-infecting viruses with key roles in biocontrol. We looked for signatures of selection between genomes of baculoviruses infecting a range of species and within a population of baculoviruses. Both analyses found only a few strong signatures of positive selection, primarily in replication- and transcription-associated genes and several structural protein genes. In both analyses, we detected a conserved complex of genes, including the helicase gene, showing consistently high levels of adaptive evolution, suggesting that they may be key in antagonistic coevolution to escape host suppression. These genes are integral to the baculovirus life cycle and may be good focal genes for developing baculoviruses as effective biocontrol agents or for targeting baculoviruses infecting ecologically relevant species. Recombination and complex genomes make evolution in these double-stranded DNA viruses more efficient than that in smaller RNA viruses with error-prone replication, as seen via signatures of selection in specific genes within a population of baculoviruses.IMPORTANCE Most viral evolutionary studies focus on RNA viruses. While these viruses cause many human and animal diseases, such studies leave us with a lesser understanding of how DNA viruses adapt to hosts and how the host responds to these pathogens. In this paper, we focus on the evolution of baculoviruses, a group of insect-infecting DNA viruses, many of which have been used in biocontrol. We find that most of the genome is under purifying selection, with only a few key genes evolving adaptively. Our results provide a glimpse into how DNA viruses differ from RNA viruses in their evolutionary dynamics and identify genes that are key to DNA virus adaptation, improving our understanding of how this group of pathogens evolves.


Asunto(s)
Evolución Molecular , Genes Virales , Nucleopoliedrovirus/genética , Selección Genética
18.
Eur J Nutr ; 57(8): 2713-2722, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28948346

RESUMEN

PURPOSE: The very old (aged ≥ 85 years), fastest growing age group in most western societies, are at especially high risk of muscle mass and strength loss. The amount, sources and timing of protein intake may play important roles in the aetiology and management of sarcopenia. This study investigated the prevalence and determinants of low protein intake in 722 very old adults participating in the Newcastle 85+ Study. METHODS: Protein intake was estimated with 2 × 24-h multiple pass recalls (24 h-MPR) and contribution (%) of food groups to protein intake was calculated. Low protein intake was defined as intake < 0.8 g of protein per adjusted body weight per day. A backward stepwise multivariate linear regression model was used to explore socioeconomic, health and lifestyle predictors of protein intake. RESULTS: Twenty-eight percent (n = 199) of the community-living very old in the Newcastle 85+ Study had low protein intake. Low protein intake was less likely when participants had a higher percent contribution of meat and meat products to total protein intake (OR 0.97, 95% CI 0.95, 1.00) but more likely with a higher percent contribution of cereal and cereal products and non-alcoholic beverages. Morning eating occasions contributed more to total protein intake in the low than in the adequate protein intake group (p < 0.001). Being a woman (p < 0.001), having higher energy intake (p < 0.001) and higher tooth count (p = 0.047) was associated with higher protein intake in adjusted models. CONCLUSION: This study provides novel evidence on the prevalence of low protein intake, diurnal protein intake patterns and food group contributors to protein intake in the very old.


Asunto(s)
Dieta con Restricción de Proteínas , Proteínas en la Dieta/administración & dosificación , Anciano , Anciano de 80 o más Años , Bebidas , Estudios de Cohortes , Grano Comestible , Femenino , Evaluación Geriátrica , Estado de Salud , Humanos , Estilo de Vida , Masculino , Evaluación Nutricional , Encuestas Nutricionales , Factores Socioeconómicos
19.
Proc Natl Acad Sci U S A ; 112(21): 6659-63, 2015 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-25964349

RESUMEN

The P-element is one of the best understood eukaryotic transposable elements. It invaded Drosophila melanogaster populations within a few decades but was thought to be absent from close relatives, including Drosophila simulans. Five decades after the spread in D. melanogaster, we provide evidence that the P-element has also invaded D. simulans. P-elements in D. simulans appear to have been acquired recently from D. melanogaster probably via a single horizontal transfer event. Expression data indicate that the P-element is processed in the germ line of D. simulans, and genomic data show an enrichment of P-element insertions in putative origins of replication, similar to that seen in D. melanogaster. This ongoing spread of the P-element in natural populations provides a unique opportunity to understand the dynamics of transposable element spread and the associated piwi-interacting RNAs defense mechanisms.


Asunto(s)
Elementos Transponibles de ADN , Drosophila/genética , Animales , Secuencia de Bases , ADN/genética , Drosophila melanogaster/genética , Evolución Molecular , Femenino , Frecuencia de los Genes , Transferencia de Gen Horizontal , Genética de Población , Genoma de los Insectos , Masculino , Datos de Secuencia Molecular , Filogenia , ARN/genética , Especificidad de la Especie , Factores de Tiempo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA