Compositional turnover and variation in Eemian pollen sequences in Europe

Vegetation History and Archaeobotany - The Eemian interglacial represents a natural experiment on how past vegetation with negligible human impact responded to amplified temperature changes...     

TORC1-regulated protein kinase Npr1 phosphorylates Orm to stimulate complex sphingolipid synthesis

The evolutionarily conserved Orm1 and Orm2 proteins mediate sphingolipid homeostasis. However, the homologous Orm proteins and the signaling pathways modulating their phosphorylation and function are incompletely characterized. Here we demonstrate that inhibition of nutrient-sensitive target of rapamycin complex 1 (TORC1) stimulates Orm phosphorylation and synthesis of complex sphingolipids in Saccharomyces cerevisiae. TORC1 inhibition activates the kinase Npr1 that directly phosphorylates and activates the Orm proteins. Npr1-phosphorylated Orm1 and Orm2 stimulate de novo synthesis of complex sphingolipids downstream of serine palmitoyltransferase. Complex sphingolipids in turn stimulate plasma membrane localization and activity of the nutrient scavenging general amino acid permease 1. Thus activation of Orm and complex sphingolipid synthesis upon TORC1 inhibition is a physiological response to starvation.     

Maternal weight affects placental DNA methylation of genes involved in metabolic pathways in the common marmoset monkey (Callithrix jacchus)

Accumulating evidence suggests that dysregulation of placental DNA methylation (DNAm) is a mechanism linking maternal weight during pregnancy to metabolic programming outcomes. The common marmoset, Callithrix jaccus, is a platyrrhine primate species that has provided much insight into studies of the primate placenta, maternal condition, and metabolic programming, yet the relationships between maternal weight and placental DNAm are unknown. Here, we report genome-wide DNAm from term marmoset placentas using reduced representation bisulfite sequencing. We identified 74 genes whose DNAm pattern is associated with maternal weight during gestation. These genes are predominantly involved in energy metabolism and homeostasis, including the regulation of glycolytic and lipid metabolic processes pathways.     

Body mass growth in common marmosets: Toward a model of pediatric obesity

While much is known about adult obesity in nonhuman primates, very little is known regarding development of childhood adiposity. As small monkeys that are easy to handle and have a relatively fast life history, common marmoset monkeys (Callithrix jacchus) offer interesting opportunities to examine the question of fat versus lean mass growth in a nonhuman primate. This article provides an overview of our understanding of early life growth in mass in marmoset monkeys, based primarily upon our past 20 years of research, culminating in our recent findings on early life obesity in this species. Common marmosets display variance in early life growth patterns that is related to both pre‐ and postnatal factors and the marmoset uterine environment is exquisitely designed to reflect resources available for the gestation of multiple offspring, making them an interesting model of developmental programming. We have demonstrated that obesity can be generated in very early life in captive marmosets, with excess adiposity evident by one month of age, making this species a potentially valuable model in which to study pediatric obesity and its sequelae. Birth weight is associated with adiposity in animals vulnerable to obesity. Early life exposure to higher fat diets enhances the chances of postweaning obesity development. However, overall higher food consumption is also associated with obesity development at later ages. One unexpected finding in our studies has been the relatively high body fat percentage of neonatal (12–18%) marmosets suggesting that hypotheses regarding the uniqueness of high human neonatal adiposity merit further examination. Am J Phys Anthropol, 2013. © 2012 Wiley Periodicals, Inc.     

Barriers and Facilitators of Participation in Sports: A Qualitative Study on Dutch Individuals with Lower Limb Amputation

Introduction

Although individuals with lower limb amputation may benefit from participation in sports, less than 40% do so.

Aim

To identify the barriers and facilitators that influence participation in sports for individuals with lower limb amputation.

Design

Qualitative study.

Participants

Twenty six individuals with lower limb amputation, all originating from the Dutch provinces of Groningen and Drenthe, of which 13 athletes.

Methods

Semi-structured interviews were used to gather information. Following thematic analysis, emerging themes were organized in three categories Technical, Social and Personal.

Results

Sport was perceived as enjoyable activity that would help participants to become and stay healthy, improve the number of social contacts, reduce phantom pain and decrease daily tension. Inadequate facilities, problematic transportation, trivialization from others, poor health and lack of motivation or the lack of a sports partner were barriers commonly mentioned by non-athletes. Remarkably, while all athletes were successful prosthetic users, the majority chose to participate in sports for which prosthesis was neither required nor needed.

Conclusions

Each individual with lower limb amputation needs to be counselled according to the barriers and facilitators he/she personally experiences. Athletes appeared to be more proactive in searching for a solution and also appeared less discouraged by failing.     

Methods for studying prion protein (PrP) metabolism and the formation of protease-resistant PrP in cell culture and cell-free systems

Transmissible spongiform encephalopathies (TSE) or prion diseases result in aberrant metabolism of prion protein (PrP) and the accumulation of a protease-resistant, insoluble, and possibly infectious form of PrP, PrP-res. Studies of PrP biosynthesis, intracellular trafficking, and degradation has been studied in a variety of tissue culture cells. Pulse-chase metabolic labeling studies in scrapie-infected cells indicated that PrP-res is made posttranslationally from an apparently normal protease sensitive precursor, PrP-sen, after the latter reaches the cell surface. Cell-free reactions have provided evidence that PrP-res itself can induce the conversion of PrP-sen to PrP-res in a highly species- and strain-specific manner. These studies have shed light on the mechanism of PrP-res formation and suggest molecular bases for TSE species barrier effects and agent strain propagation.     

Relations among birth condition, maternal condition, and postnatal growth in captive common marmoset monkeys (Callithrix jacchus)

The present study characterizes the relations among maternal condition, litter size, birth condition, and growth in body weight for a population of common marmosets. The subjects of the study were marmosets born into a single colony between 1994 and 2001. Three sets of analyses were conducted to answer the following questions: 1) Is there a relationship between litter size, maternal condition, and birth condition? In the study population, maternal body weight, maternal age, litter size, and birth condition were related in a complex fashion. Birth weight and prenatal long‐bone growth, as reflected in knee–heel length, were both related to maternal age, with older mothers supporting higher prenatal growth. Age and maternal condition appeared to interact as determinants of long‐bone growth, as the combination of older and larger mothers resulted in significantly longer knee–heel lengths in their offspring. 2) Is there a relationship between birth condition or maternal condition and subsequent growth or final adult size? The early growth rate in this population was similar to early growth rates reported for three different marmoset colonies, suggesting that early growth may be relatively inflexible in this species. However, within this population, the variation that did occur in early growth rate was related to birth weight and maternal weight. Later growth and adult weight were related to birth weight and litter size: small twin infants displayed slower later growth rates and were smaller as adults than twins that began life at a higher birth weight, while the birth weight of triplets was not related to adult size. In these marmosets, small infants that were the result of increased litter size differed from small infants whose small birth size resulted from other factors. This reinforces the proposal that the causes of low birth weight will be relevant to the development of the marmoset as a model of prenatal environmental effects. Am. J. Primatol. 62:83–94, 2004. © 2004 Wiley‐Liss, Inc.     

Molecular basis of scrapie strain glycoform variation

Transmissible spongiform encephalopathies (TSE) are characterized by the conversion of a protease-sensitive host glycoprotein, prion protein or PrP-sen, to a protease-resistant form (PrP-res). PrP-res molecules that accumulate in the brain and lymphoreticular system of the host consist of three differentially glycosylated forms. Analysis of the relative amounts of the PrP-res glycoforms has been used to discriminate TSE strains and has become increasingly important in the differential diagnosis of human TSEs. However, the molecular basis of PrP-res glycoform variation between different TSE agents is unknown. Here we report that PrP-res itself can dictate strain-specific PrP-res glycoforms. The final PrP-res glycoform pattern, however, can be influenced by the cell and significantly altered by subtle changes in the glycosylation state of PrP-sen. Thus, strain-specific PrP-res glycosylation profiles are likely the consequence of a complex interaction between PrP-res, PrP-sen, and the cell and may indicate the cellular compartment in which the strain-specific formation of PrP-res occurs.