A deer (subfamily Cervinae) genetic linkage map and the evolution of ruminant genomes

Comparative maps between ruminant species and humans are increasingly important tools for the discovery of genes underlying economically important traits. In this article we present a primary linkage map of the deer genome derived from an interspecies hybrid between red deer (Cervus elaphus) and Père David's deer (Elaphurus davidianus). The map is approximately 2500 cM long and contains >600 markers including both evolutionary conserved type I markers and highly polymorphic type II markers (microsatellites). Comparative mapping by annotation and sequence similarity (COMPASS) was demonstrated to be a useful tool for mapping bovine and ovine ESTs in deer. Using marker order as a phylogenetic character and comparative map information from human, mouse, deer, cattle, and sheep, we reconstructed the karyotype of the ancestral Pecoran mammal and identified the chromosome rearrangements that have occurred in the sheep, cattle, and deer lineages. The deer map and interspecies hybrid pedigrees described here are a valuable resource for (1) predicting the location of orthologs to human genes in ruminants, (2) mapping QTL in farmed and wild deer populations, and (3) ruminant phylogenetic studies.     

Identification of cysteine residues responsible for oxidative cross-linking and chemical inhibition of human nucleoside-triphosphate diphosphohydrolase 3.

Cysteine-to-serine mutations were constructed to test the functional and structural significance of the three non-extracellular cysteine residues in ecto-nucleoside-triphosphate diphosphohydrolase 3 (eNTPDase3). None of these cysteines were found to be essential for enzyme activity. However, Cys(10), located on the short N-terminal cytoplasmic tail, was found to be responsible for dimer formation occurring via oxidation during membrane preparation as well as for dimer cross-linking resulting from exogenously added sulfhydryl-specific cross-linking agents. The resistance to further cross-linking of these dimers into higher order oligomers by lysine-specific cross-linkers suggests that this enzyme may form its native tetrameric structure as a "dimer of dimers" with nonequivalent interactions between subunits. Cys(501), located in the hydrophobic C-terminal membrane-spanning domain of eNTPDase3, was found to be the site of chemical modification by a sulfhydryl-specific reagent, p-chloromercuriphenylsulfonic acid (pCMPS), leading to inhibition of enzyme activity. The effect of pCMPS was negligible after dissociation of the enzyme into monomers by Triton X-100, suggesting that the mechanism of inhibition is dependent on the oligomeric structure. Because Cys(501) is accessible for modification by the membrane-impermeant reagent pCMPS, we hypothesize that eNTPDase3 (and possibly other eNTPDases) contains a water-filled crevice allowing access of water and hydrophilic compounds to at least part of the protein's C-terminal membrane-spanning helix.     

Protein-heparin interactions measured by BIAcore 2000 are affected by the method of heparin immobilization

Surface plasmon resonance (SPR) biosensors such as the BIAcore 2000 are a useful tool for the analysis of protein-heparin interactions. Generally, biotinylated heparin is captured on a streptavidin-coated surface to create heparinized surfaces for subsequent binding analyses. In this study we investigated three commonly used techniques for the biotinylation of heparin, namely coupling through either carboxylate groups or unsubstituted amines along the heparin chain, or through the reducing terminus of the heparin chain. Biotinylated heparin derivatives were immobilized on streptavidin sensor chips and several heparin-binding proteins were examined. Of the surfaces investigated, heparin attached through the reducing terminus had the highest binding capacity, and in some cases had a higher affinity for the proteins tested. Heparin immobilized via intrachain bare amines had intermediate binding capacity and affinity, and heparin immobilized through the carboxylate groups of uronic acids had the lowest capacity for the proteins tested. These results suggest that immobilizing heparin to a surface via intrachain modifications of the heparin molecule can affect the binding of particular heparin-binding proteins.     

Studies on Inhibition of Intestinal Absorption of Radioactive Strontium: II. Effects of Administration of Sodium Alginate by Orogastric Intubation and Feeding

A method is reported that enables selective suppression of absorption of radioactive strontium from ingested food material, permitting calcium to remain available to the body. Studies were carried out by measuring blood levels and bone uptake of Sr⁸⁹ and Ca⁴⁵ at different time intervals after orogastric intubation of rats. The addition of sodium alginate, derived from brown marine algae, to the radioactive isotopes increased the overall physiological discrimination against strontium by amounts up to 60% after 24 hours. This discrimination was further increased by feeding sodium alginate mixed with standard diet in the proportions of 20:80 and 30:70. The observed ratio was reduced by administration of sodium alginate from 0.25 to 0.09.Determination of the limiting dosage in rats is restricted to the amounts which rats will consume. In the event of an inadvertent release of radioactive strontium, human subjects probably could increase their intake of alginate at will, permitting a greater effectiveness of sodium alginate than could be obtained in experimental animals.     

Studies on the Inhibition of Intestinal Absorption of Radioactive Strontium: III. The Effect of Administration of Sodium Alginate in Food and in Drinking Water

A method is reported which permits selective suppression of absorption of radioactive strontium from ingested food material, permitting calcium to be available to the body. Studies were carried out by measuring bone uptake of Sr⁸⁹ and Ca⁴⁵ when various amounts of sodium alginate were fed with the diet. Long-term studies were made in which two different levels of radioactivity were used, to determine the pattern of Sr⁸⁹ deposition with continuous intake of binding agent. It was found that administration of sodium alginate as a jelly overcomes the problem of constipation and effectively reduces Sr⁸⁹ uptake, up to 83%. This fact represents a significant finding with respect to the use of the compound in human subjects. Addition of sodium alginate to drinking water is effective with low levels of Sr⁸⁹ intake.This naturally occurring water-soluble macromolecular substance possesses several advantages in use for the suppression of absorption of radioactive strontium when compared with synthetic ion exchange resins: there is no disturbance of electrolyte balance; efficiency is not reduced by treatment over a prolonged period of time; and finally, the product is palatable.     

Correlates of Total Sedentary Time and Screen Time in 9–11 Year-Old Children around the World: The International Study of Childhood Obesity,Lifestyle and the Environment

Purpose

Previously, studies examining correlates of sedentary behavior have been limited by small sample size, restricted geographic area, and little socio-cultural variability. Further, few studies have examined correlates of total sedentary time (SED) and screen time (ST) in the same population. This study aimed to investigate correlates of SED and ST in children around the world.

Methods

The sample included 5,844 children (45.6% boys, mean age = 10.4 years) from study sites in Australia, Brazil, Canada, China, Colombia, Finland, India, Kenya, Portugal, South Africa, the United Kingdom, and the United States. Child- and parent-reported behavioral, household, and neighborhood characteristics and directly measured anthropometric and accelerometer data were obtained. Twenty-one potential correlates of SED and ST were examined using multilevel models, adjusting for sex, age, and highest parental education, with school and study site as random effects. Variables that were moderately associated with SED and/or ST in univariate analyses (p<0.10) were included in the final models. Variables that remained significant in the final models (p<0.05) were considered correlates of SED and/or ST.

Results

Children averaged 8.6 hours of daily SED, and 54.2% of children failed to meet ST guidelines. In all study sites, boys reported higher ST, were less likely to meet ST guidelines, and had higher BMI z-scores than girls. In 9 of 12 sites, girls engaged in significantly more SED than boys. Common correlates of higher SED and ST included poor weight status, not meeting physical activity guidelines, and having a TV or a computer in the bedroom.

Conclusions

In this global sample many common correlates of SED and ST were identified, some of which are easily modifiable (e.g., removing TV from the bedroom), and others that may require more intense behavioral interventions (e.g., increasing physical activity). Future work should incorporate these findings into the development of culturally meaningful public health messages.