Ontogenetic dietary information of the California sea lion (Zalophus californianus) assessed using stable isotope analysis

We used stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopes to examine ontogenetic dietary changes in 289 California sea lions (Zalophus californianus) at San Miguel Island, California during 2004–2007. Tissues analyzed included fur, red blood cells, plasma, and serum. For all tissues, pups had higher δ¹⁵N values and lower δ¹³C values compared to adults, which indicated that pups were feeding higher trophically than older conspecifics and on a lipid‐rich milk diet prior to weaning. Yearling δ¹⁵N values were slightly lower than pup or nearly indistinguishable from adult values depending on the tissue analyzed, indicating a dietary shift from maternal dependency to independent foraging. Juveniles (2–4 yr) and adults (>4 yr) had similar δ¹⁵N values indicating they fed at a similar trophic level. There did not appear to be a pronounced dietary shift in δ¹³C values. However, δ¹³C values integrated with telemetry data indicated that postweaned individuals fed in similar foraging areas. Dietary changes during early life stages may be due to differences in physiology, morphology, experience, or energetic requirements; however, young animals are able to attain the skills needed to consume adult prey types near the end of their second year of life.     

Adh 1 first intron polymorphisms in Argentinean populations of Ceratitis capitata

DNA size polymorphisms were utilized in a study of 24 natural populations of Ceratitis capitata Wiedemann (Diptera: Tephritidae) from Argentina. The first intron of alcohol dehydrogenase 1 gene (Adh₁) was amplified using exon priming intron crossing‐polymerase chain reaction. Three size variants were detected among the 307 samples analyzed. To better differentiate the size variants, further digestion of PCR products with the EcoRI restriction enzyme was carried out. Complete nucleotide sequences of the three‐allele variants were obtained and single changes, insertions, deletions, and EcoRI recognition sites were located. Population allele frequencies were analyzed and a global mean heterozygosity (He) of 0.33 was obtained. In most populations, observed allelic frequencies conformed to Hardy–Weinberg expectations. Significant differences between provinces and sampling sites within these provinces, and among some populations were found. The average number of insects exchanged among populations (Nm) was estimated and high values were observed between Argentina and populations from two African countries (Morocco and Kenya), Australia, and Hawaii (Kauai). Pest introduction sources and dispersion patterns in Argentina are discussed based on these results as well as on available bibliographical data.     

Non-synonymous polymorphisms in the P2RX 4 are related to bone mineral density and osteoporosis risk in a cohort of Dutch fracture patients

In the present study we investigated whether single nucleotide polymorphisms (SNPs) in the P2RX₄, which alter the P2X₄R function, are associated with the development of osteoporosis and whether an interaction between the P2X₄R and P2X₇R confer a synergistic effect of these two receptors on osteoporosis risk. Patients with fracture (690 females and 231 males, aged ≥50 years) were genotyped for three non-synonymous P2X₄R SNPs. Bone mineral density (BMD) was measured at the total hip, lumbar spine, and femoral neck. Subject carrying the variant allele of the Tyr315Cys polymorphism showed a 2.68-fold (95 % CI, 1.20–6.02) higher risk of osteoporosis compared with wild-type subject. Furthermore, significant lower lumbar spine BMD values were observed in subjects carrying the Cys315 allele as compared with wild-type (0.85 ± 0.17 and 0.93 ± 0.17 g/cm², respectively; p < 0.001). Assuming a recessive model, carriers of the variant allele of the Ser242Gly polymorphism showed increased BMD values at the lumbar spine compare to wild-type subject (1.11 ± 0.35 and 0.92 ± 0.17 g/cm², respectively; p = 0.0045). This is the first study demonstrating an association of non-synonymous polymorphisms in the P2RX₄ and the risk of osteoporosis, suggesting a role of the P2X₄R in the regulation of bone mass.

Electronic supplementary material

The online version of this article (doi:10.1007/s11302-012-9337-0) contains supplementary material, which is available to authorized users.     

Stochastic Approximation Boosting for Incomplete Data Problems

Summary Boosting is a powerful approach to fitting regression models. This article describes a boosting algorithm for likelihood‐based estimation with incomplete data. The algorithm combines boosting with a variant of stochastic approximation that uses Markov chain Monte Carlo to deal with the missing data. Applications to fitting generalized linear and additive models with missing covariates are given. The method is applied to the Pima Indians Diabetes Data where over half of the cases contain missing values.     

Cardiac recovery by stem and progenitor cells

For the 20th time in a row, the Netherlands Society of Cardiology (NVVC), the Interuniversity Cardiology Institute of the Netherlands (ICIN), and the sponsor, Sanofi-Aventis, have supported the competition for the best three PhD theses on a cardiovascular subject published last year. The prize carries the name of one of the great Dutchmen in the history of cardiology: Willem Einthoven (1860–1927), the pioneer of the human ECG and winner of the Nobel Prize in 1924.