Early life vitamin D depletion and mechanical loading determine methylation changes in the RUNX2, RXRA, and osterix promoters in mice.

BACKGROUND: Early life vitamin D exposure is linked to later skeletal health with maternal vitamin D status in pregnancy associated with neonatal bone mass. The MAVIDOS study has demonstrated that vitamin D supplementation leads to reduced RXRA DNA methylation. Mice exposed to early life vitamin D deficiency have reduced bone mass and bone accrual in response to mechanical loading. Using the tibiae of these mice, we have examined the effect of diet and mechanical loading on the DNA methylation of promoters of genetic loci important for bone growth and development and their association with bone strength. RESULTS: Mechanical loading of mouse tibiae leads to a reduction of RXRA DNA methylation. Early life vitamin D deficiency is associated with altered methylation of osterix and Runx2 in these bones. Tibia strength was also demonstrated to be associated with a change in DNA methylation status in CpGs of the vitamin D receptor (VDR), ostrix, and RXRA genes. CONCLUSIONS: We have shown for the first time that mechanical loading of bone and early life vitamin D deficiency leads to changes in the epigenome of this tissue in key genes in the vitamin D and osteoblast differentiation pathway.

Genetic imprints of Brosimum alicastrum Sw. in Mexico.

PREMISE: The mechanisms generating the geographical distributions of genetic diversity are a central theme in evolutionary biology. The amount of genetic diversity and its distribution are controlled by several factors, including dispersal abilities, physical barriers, and environmental and climatic changes. We investigated the patterns of genetic diversity and differentiation among populations of the widespread species Brosimum alicastrum in Mexico. METHODS: Using nuclear DNA microsatellite data, we tested whether the genetic structure of B. alicastrum was associated with the roles of the Trans-Mexican Volcanic Belt and the Isthmus of Tehuantepec as geographical barriers to gene flow and to infer the role of past events in the genetic diversity patterns. We further used a maximum-likelihood population-effects mixed model (MLPE) to identify the main factor affecting population differentiation in B. alicastrum. RESULTS: Our results suggested that Mexican B. alicastrum is well differentiated into three main lineages. Patterns of the genetic structure at a finer scale did not fully correspond to the current geographical barriers to gene flow. According to the MLPE mixed model, isolation by distance is the best model for explaining the genetic differentiation of B. alicastrum in Mexico. CONCLUSIONS: We propose that the differentiation patterns might reflect (1) an ancient differentiation that occurred in Central and South America, (2) the effects of past climatic changes, and (3) the functions of some physical barriers to gene flow. This study provides insights into the possible mechanisms underlying the geographic genetic variation of B. alicastrum along a moisture gradient in tropical lowland forests.

Whole-body energy transfer strategies during football instep kicking: implications for training practices.

Knowledge of whole-body energy transfer strategies during football instep kicking can help inform empirically grounded training practices. The aim of this study was thus to investigate energy transfer strategies of 15 semi-professional players performing kicks for speed and accuracy. Three-dimensional kinematics and GRFs (both 1000 Hz) were incorporated into segment power analyses to derive energy transfers between the support leg, torso, pelvis and kick leg throughout the kick. Energy transferred from support leg (r = 0.62, P = 0.013) and torso (r = 0.54, P = 0.016) into the pelvis during tension arc formation and leg cocking was redistributed to the kick leg during the downswing (r = 0.76, P < 0.001) and were associated with faster foot velocities at ball contact. This highlights whole-body function during instep kicking. Of particular importance were: (a) regulating support leg energy absorption, (b) eccentric formation and concentric release of a 'tension arc' between the torso and kicking hip, and (c) coordinated proximal to distal sequencing of the kick leg. Resistance exercises that replicate the demands of these interactions may help develop more powerful kicking motions and varying task and/or environmental constraints might facilitate development of adaptable energy transfer strategies.

Isolation and characterization of microsatellites for the neotropical dioecious palm Chamaedorea tepejilote (Arecaceae) and cross-amplification in other Chamaedorea species.

Palms are important components of tropical and subtropical ecosystems and have even been considered keystone plant resources that can support a large array of pollinators and frugivores. Palms are also economically important. Chamaedorea tepejilote Liebm. is a widely distributed palm with important bioeconomic potential for food, traditional medicine and ornamental purposes. Eighteen microsatellite primers were developed for C. tepejilote. Polymorphism and genetic diversity were evaluated in 71 individuals from four populations in Costa Rica. Thirteen loci were polymorphic and the number of alleles in the pooled sample ranged between 5 and 20, the average number of alleles was 10.61. Average observed heterozygosity was Ho = 0.607 ± 0.04 (SD) and the average expected heterozygosity was He = 0.600 ± 0.03. The exclusion probability of the combined 13 loci, was PE = 0.998. We tested transferability of the markers in the congeneric C. costaricana, C. pinnantifrons and C. macrospadix. Dioecious species are common in tropical forests; however, few studies have analyzed gene flow patterns in these species. The markers developed for C. tepejilote are an important tool to quantify gene flow patterns and the distribution of genetic diversity within populations. This information will be useful for the development of conservation and management practices of this dioecious tropical palm species.

Isolation and characterization of microsatellite loci in Astroniumgraveolens (Anacardiaceae) and cross amplification in related species.

Microsatellite markers are a useful genetic tool to answer ecological and conservation genetics questions. Microsatellite primers were developed and characterized to evaluate forest fragmentation effects on genetic structure, diversity and gene flow patterns in the dioecious tropical tree Astroniumgraveolens (Anacardiaceae). Using genomic library enrichment, sixteen microsatellite loci were developed for A.graveolens. Polymorphism was evaluated in 80 individuals from four localities in Mexico. The overall number of alleles detected was 63, average alleles per locus 3.9 with a range from one to 11 per locus. Cross amplification trails on related species in the Anacardiaceae family: Spondiaspurpurea and Amphipterygiumadstringens, achieved successful amplification for all primers. Microsatellite markers described here are the first to be characterized for A.graveolens. These genetic markers will be a useful tool to assess the genetic consequences of habitat fragmentation and selective logging on A.graveolens populations. Cross amplification success on S.purpureaandA.adstringens suggest that they may be used for population genetic studies in other species within the family.

Isolation and characterization of microsatellites loci in Spondias purpurea (Anacardiaceae) and cross amplification in congeneric species.

Microsatellite markers provide high polymorphism levels, useful to study genetic diversity and gene flow patterns in plant populations. Here we develop and characterize microsatellite primers to evaluate patterns of genetic structure and diversity, and gene flow levels in the dioecious tropical tree Spondias purpurea (Anacardiaceae). Twenty-four microsatellite primers were developed for Spondias purpurea. Polymorphism was evaluated in 139 individuals from three localities in Mexico. Ten loci were polymorphic. The number of alleles ranged between two and 21, the average number of alleles was 5.88. Cross-amplification trials on S. mombin, S. radlkoferi, Astronium graveolens and Amphipterygium adstringens achieved successful amplification for only six microsatellites in S. mombin and S. radlkoferi. Microsatellites developed for S. purpurea will be a useful tool to estimate genetic diversity within and among populations, as well as to assess the consequences of habitat fragmentation on gene flow patterns of this species.

Screening in the community to reduce fractures in older women (SCOOP): a randomised controlled trial.

BACKGROUND: Despite effective assessment methods and medications targeting osteoporosis and related fractures, screening for fracture risk is not currently advocated in the UK. We tested whether a community-based screening intervention could reduce fractures in older women. METHODS: We did a two-arm randomised controlled trial in women aged 70-85 years to compare a screening programme using the Fracture Risk Assessment Tool (FRAX) with usual management. Women were recruited from 100 general practitioner (GP) practices in seven regions of the UK: Birmingham, Bristol, Manchester, Norwich, Sheffield, Southampton, and York. We excluded women who were currently on prescription anti-osteoporotic drugs and any individuals deemed to be unsuitable to enter a research study (eg, known dementia, terminally ill, or recently bereaved). The primary outcome was the proportion of individuals who had one or more osteoporosis-related fractures over a 5-year period. In the screening group, treatment was recommended in women identified to be at high risk of hip fracture, according to the FRAX 10-year hip fracture probability. Prespecified secondary outcomes were the proportions of participants who had at least one hip fracture, any clinical fracture, or mortality; and the effect of screening on anxiety and health-related quality of life. This trial is registered with the International Standard Randomised Controlled Trial registry, number ISRCTN 55814835. FINDINGS: 12 483 eligible women were identified and participated in the trial, and 6233 women randomly assigned to the screening group between April 15, 2008, and July 2, 2009. Treatment was recommended in 898 (14%) of 6233 women. Use of osteoporosis medication was higher at the end of year 1 in the screening group compared with controls (15% vs 4%), with uptake particularly high (78% at 6 months) in the screening high-risk subgroup. Screening did not reduce the primary outcome of incidence of all osteoporosis-related fractures (hazard ratio [HR] 0·94, 95% CI 0·85-1·03, p=0·178), nor the overall incidence of all clinical fractures (0·94, 0·86-1·03, p=0·183), but screening reduced the incidence of hip fractures (0·72, 0·59-0·89, p=0·002). There was no evidence of differences in mortality, anxiety levels, or quality of life. INTERPRETATION: Systematic, community-based screening programme of fracture risk in older women in the UK is feasible, and could be effective in reducing hip fractures. FUNDING: Arthritis Research UK and Medical Research Council.

ANRIL Promoter DNA Methylation: A Perinatal Marker for Later Adiposity.

Experimental studies show a substantial contribution of early life environment to obesity risk through epigenetic processes. We examined inter-individual DNA methylation differences in human birth tissues associated with child's adiposity. We identified a novel association between the level of CpG methylation at birth within the promoter of the long non-coding RNA ANRIL (encoded at CDKN2A) and childhood adiposity at age 6-years. An association between ANRIL methylation and adiposity was also observed in three additional populations; in birth tissues from ethnically diverse neonates, in peripheral blood from adolescents, and in adipose tissue from adults. Additionally, CpG methylation was associated with ANRIL expression in vivo, and CpG mutagenesis in vitro inhibited ANRIL promoter activity. Furthermore, CpG methylation enhanced binding to an Estrogen Response Element within the ANRIL promoter. Our findings demonstrate that perinatal methylation at loci relevant to gene function may be a robust marker of later adiposity, providing substantial support for epigenetic processes in mediating long-term consequences of early life environment on human health.

The effectiveness of a real life dose reduction strategy for tumour necrosis factor inhibitors in ankylosing spondylitis and psoriatic arthritis.

OBJECTIVE: To determine feasibility of TNF inhibitor (TNFi) dose reduction for severe AS and PsA patients. METHODS: A retrospective study in a real-world setting. Criteria for dose reduction of TNFi included BASDAI < 4 for ⩾6 months in AS; or DAS28-ESR ⩽ 3.2 for ⩾6 months in PsA. TNFi dose was reduced by one-third. Patients who flared (BASDAI > 4 in AS or DAS28-ESR > 3.2 in PsA) were re-escalated to standard treatment dose. RESULTS: Twenty-six per cent (33/125) of AS and 18% (15/83) of PsA patients fulfilled criteria and underwent TNFi dose reduction. Fifty-eight per cent (19/33) of AS and 60% (9/15) of PsA patients maintained TNFi dose reduction for mean (s.d) of 1.0 (0.8) years. Reinstating standard dose of TNFi recaptured low disease activity in all patients who failed dose reduction within 24 weeks, with no statistically significant difference in mean BASDAI compared with those maintaining TNFi dose reduction in AS at 24 weeks [mean (s.d) BASDAI 2.4 (1.1) vs 1.9 (1.5), respectively (P = 0.229)]; however in PsA, those who failed dose reduction had higher disease activity compared with patients maintained on TNFi dose reduction at 24 weeks [mean (s.d) DAS28-ESR 2.7 (0.6) vs 1.3 (0.5), respectively (P ⩽ 0.001)]. In PsA, a lower DAS28-ESR prior to dose reduction of TNFi was associated with more successful dose reduction. CONCLUSIONS: In a real-world setting, 60% of individuals with severe AS and PsA who achieve low disease activity can successfully reduce the dose of TNFi therapy by a third for a mean of 1 year.

Development and characterization of microsatellite primers in the endangered Mediterranean shrub Ziziphus lotus (Rhamnaceae).

PREMISE OF THE STUDY: Microsatellite primers were developed to characterize and evaluate patterns of genetic diversity and structure in the endangered Mediterranean shrub Ziziphus lotus (Rhamnaceae). METHODS AND RESULTS: Twenty microsatellite primers were developed for Z. lotus, of which 14 were polymorphic. We evaluated microsatellite polymorphism in 97 specimens from 18 Spanish and seven Moroccan populations. Between two and eight alleles were found per locus, and the average number of alleles was 5.54. Observed heterozygosity and expected heterozygosity ranged from 0.08 to 0.90 and from 0.08 to 0.82, respectively. Nine of these primers also amplified microsatellite loci in Z. jujuba. CONCLUSIONS: The microsatellite markers described here will be useful in studies on genetic variation, population genetic structure, and gene flow in the fragmented habitat of this species. These markers are a valuable resource for designing appropriate conservation measures for the species in the Mediterranean range.

Isolation and characterization of 12 microsatellite loci in soapbark, Quillaja saponaria (Quillajaceae).

PREMISE OF THE STUDY: Microsatellite primers were developed for the endemic Chilean tree Quillaja saponaria (Quillajaceae), a common member of the sclerophyllous Mediterranean forest, to investigate intraspecific patterns of genetic diversity and structure. METHODS AND RESULTS: Using an enriched library, 12 polymorphic microsatellite loci were developed in Q. saponaria. All loci consisted of dinucleotide repeats. The average number of alleles per locus was 5.3 (2-13), with a total of 64 alleles recorded in 39 individuals from three populations. CONCLUSIONS: The microsatellite markers described here are the first characterized for Q. saponaria. The polymorphic loci will be useful in studies of genetic diversity and genetic population differentiation in natural populations of this species.

Host phenology and geography as drivers of differentiation in generalist fungal mycoparasites.

The question as to why parasites remain generalist or become specialist is a key unresolved question in evolutionary biology. Ampelomyces spp., intracellular mycoparasites of powdery mildew fungi, which are themselves plant pathogens, are a useful model for studies of this issue. Ampelomyces is used for the biological control of mildew. Differences in mycohost phenology promote temporal isolation between sympatric Ampelomyces mycoparasites. Apple powdery mildew (APM) causes spring epidemics, whereas other powdery mildew species on plants other than apple cause epidemics later in the season. This has resulted in genetic differentiation between APM and non-APM strains. It is unclear whether there is genetic differentiation between non-APM Ampelomyces lineages due to their specialization on different mycohosts. We used microsatellites to address this question and found no significant differentiation between non-APM Ampelomyces strains from different mycohosts or host plants, but strong differentiation between APM and non-APM strains. A geographical structure was revealed in both groups, with differences between European countries, demonstrating restricted dispersal at the continent scale and a high resolution for our markers. We found footprints of recombination in both groups, possibly more frequent in the APM cluster. Overall, Ampelomyces thus appears to be one of the rare genuine generalist pathogenic fungi able to parasitize multiple hosts in natural populations. It is therefore an excellent model for studying the evolution of pathogens towards a generalist rather than host-specific strategy, particularly in light of the tritrophic interaction between Ampelomyces mycoparasites, their powdery mildew fungal hosts and the mildew host plants.

Development and characterization of microsatellite loci in the mistletoe Psittacanthus schiedeanus (Loranthaceae).

PREMISE OF THE STUDY: Microsatellite primers were developed for the parasitic Psittacanthus schiedeanus, a common mistletoe species on cloud forest-adapted tree hosts in Mesoamerica, to investigate intraspecific genetic patterns of diversity and genetic structure. • METHODS AND RESULTS: Using an enriched library, 10 polymorphic microsatellite loci were developed in P. schiedeanus. All loci consisted of dinucleotide repeats. Average alleles per locus were 12 (4-17), and a total of 120 alleles were recorded across 39 individuals from four populations in Mexico. Primers were tested in 11 additional species, but only amplified successfully in P. calyculatus and P. angustifolius. • CONCLUSIONS: The polymorphic loci described will be useful in studies of genetic diversity and genetic population differentiation in natural populations of these parasitic plants, and will provide valuable information to understand the importance of host distribution.

Temporal isolation explains host-related genetic differentiation in a group of widespread mycoparasitic fungi.

Understanding the mechanisms responsible for divergence and specialization of pathogens on different hosts is of fundamental importance, especially in the context of the emergence of new diseases via host shifts. Temporal isolation has been reported in a few plants and parasites, but is probably one of the least studied speciation processes. We studied whether temporal isolation could be responsible for the maintenance of genetic differentiation among sympatric populations of Ampelomyces, widespread intracellular mycoparasites of powdery mildew fungi, themselves plant pathogens. The timing of transmission of Ampelomyces depends on the life cycles of the powdery mildew species they parasitize. Internal transcribed spacer sequences and microsatellite markers showed that Ampelomyces populations found in apple powdery mildew (Podosphaera leucotricha) were genetically highly differentiated from other Ampelomyces populations sampled from several other powdery mildew species across Europe, infecting plant hosts other than apple. While P. leucotricha starts its life cycle early in spring, and the main apple powdery mildew epidemics occur before summer, the fungal hosts of the other Ampelomyces cause epidemics mainly in summer and autumn. When two powdery mildew species were experimentally exposed to Ampelomyces strains naturally occurring in P. leucotricha in spring, and to strains naturally present in other mycohost species in autumn, cross-infections always occurred. Thus, the host-related genetic differentiation in Ampelomyces cannot be explained by narrow physiological specialization, because Ampelomyces were able to infect powdery mildew species they were unlikely to have encountered in nature, but instead appears to result from temporal isolation.

Epidemiology of hip fracture: Worldwide geographic variation.

Osteoporosis is a major health problem, especially in elderly populations, and is associated with fragility fractures at the hip, spine, and wrist. Hip fracture contributes to both morbidity and mortality in the elderly. The demographics of world populations are set to change, with more elderly living in developing countries, and it has been estimated that by 2050 half of hip fractures will occur in Asia. This review conducted using the PubMed database describes the incidence of hip fracture in different regions of the world and discusses the possible causes of this wide geographic variation. The analysis of data from different studies show a wide geographic variation across the world, with higher hip fracture incidence reported from industrialized countries as compared to developing countries. The highest hip fracture rates are seen in North Europe and the US and lowest in Latin America and Africa. Asian countries such as Kuwait, Iran, China, and Hong Kong show intermediate hip fracture rates. There is also a north-south gradient seen in European studies, and more fractures are seen in the north of the US than in the south. The factors responsible of this variation are population demographics (with more elderly living in countries with higher incidence rates) and the influence of ethnicity, latitude, and environmental factors. The understanding of this changing geographic variation will help policy makers to develop strategies to reduce the burden of hip fractures in developing countries such as India, which will face the brunt of this problem over the coming decades.

A genetic linkage map of Venturia inaequalis, the causal agent of apple scab.

BACKGROUND: Venturia inaequalis is an economically-important disease of apple causing annual epidemics of scab worldwide. The pathogen is a heterothallic ascomycete with an annual cycle of sexual reproduction on infected apple leaf litter, followed by several cycles of asexual reproduction during the apple growing season. Current disease control is achieved mainly through scheduled applications of fungicides. Genetic linkage maps are essential for studying genome structure and organisation, and are a valuable tool for identifying the location of genes controlling important traits of interest such as avirulence, host specificity and mating type in V. inaequalis. In this study, we performed a wide cross under in vitro conditions between an isolate of V. inaequalis from China and one from the UK to obtain a genetically diverse mapping population of ascospore progeny isolates and produced a map using AFLP and microsatellite (SSR) markers. FINDINGS: Eighty-three progeny were obtained from the cross between isolates C0154 (China) x 01/213 (UK). The progeny was screened with 18 AFLP primer combinations and 31 SSRs, and scored for the mating type locus MAT. A linkage map was constructed consisting of 294 markers (283 AFLPs, ten SSRs and the MAT locus), spanning eleven linkage groups and with a total map length of 1106 cM. The length of individual linkage groups ranged from 30.4 cM (Vi-11) to 166 cM (Vi-1). The number of molecular markers per linkage group ranged from 7 on Vi-11 to 48 on Vi-3; the average distance between two loci within each group varied from 2.4 cM (Vi-4) to 7.5 cM (Vi-9). The maximum map length between two markers within a linkage group was 15.8 cM. The MAT locus was mapped to a small linkage group and was tightly linked to two AFLP markers. The map presented is over four times longer than the previously published map of V. inaequalis which had a total genetic distance of just 270 cM. CONCLUSION: A genetic linkage map is an important tool for investigating the genetics of important traits in V. inaequalis such as virulence factors, aggressiveness and mating type. The linkage map presented here represents a significant improvement over currently published maps for studying genome structure and organisation, and for mapping genes of economic importance on the V. inaequalis genome.

Variations in infant feeding practice are associated with body composition in childhood: a prospective cohort study.

CONTEXT: Most studies of infant diet and later body composition focus on milk feeding; few consider the influence of variations in the weaning diet. OBJECTIVE: Our objective was to examine how variations in milk feeding and the weaning diet relate to body composition at 4 yr. STUDY POPULATION: A total of 536 children participating in a prospective birth cohort study. DESIGN: Diet was assessed at 6 and 12 months of age. Compliance with weaning guidance was defined by the infant's score for a principal component analysis-defined dietary pattern (infant guidelines) at 12 months. Infants with high infant guidelines scores had diets characterized by high consumption of fruit, vegetables, and home-prepared foods. Body composition was assessed at 4 yr by dual x-ray absorptiometry. RESULTS: Longer duration of breastfeeding was associated with lower fat mass at 4 yr [4.5 kg, 95% confidence interval (CI) of 4.3-4.7 kg, in children breastfed for 12 months or more, compared with 5.0 (95% CI 4.7-5.3) kg in children never breastfed (P = 0.002)] but was not related to body mass index. Children with high infant guidelines scores had a higher lean mass [12.6 (95% CI 12.3-12.9) kg in children in the top quarter of the distribution, compared with 12.0 (95% CI 11.7-12.4) kg in children in the bottom quarter (P = 0.001)]. These associations were independent and were little changed by adjustment for confounding factors. CONCLUSIONS: These data suggest that variations in both milk feeding and in the weaning diet are linked to differences in growth and development, and they have independent influences on body composition in early childhood.