Anthropometric and physiological predictors of flat-water 1000 m kayak performance in young adolescents and the effectiveness of a high volume training camp.

Our purpose was to determine the relationship of anthropometric and physiological variables with 1000m flat-water kayak (K1000) performance. A secondary purpose was to determine the effectiveness of a high volume training camp. High performance young adolescent kayakers (n=13, 8 males, 5 females, 15±1 yrs) participated in this study. Testing before and after the 3-4 week training camp included anthropometric measurements (height, sitting height, arm span, and body mass), strength (1-RM: bench press and bench pull), flexibility (sit and reach), and an incremental kayak ergometer test to determine peak oxygen uptake (VO2peak) and anaerobic threshold, and an open water K1000 time trial. K1000 time was significantly correlated with height (r=-0.81; p\u3c0.01), sitting height (r=-0.85; p\u3c0.01), arm span (r=-0.87; p\u3c0.01), bench press (r=-0.92; p\u3c0.01), bench pull (r=-0.85; p\u3c0.01), VO2peak (r=-0.87; p\u3c0.01) and anaerobic threshold (r=-0.83; p\u3c0.05). Following the training camp there were no significant differences in body mass, strength, and VO2 peak, however, anaerobic threshold (33.6±6.2 to 42.3±8.8 ml•kg-1•min-1, p=0.001) and K1000 (302±44 to 289±31 sec, p=0.007) significantly improved. The results of this study suggest that K1000 performance in young adolescent kayakers appears to require a high aerobic and strength contribution and that a high volume training camp is effective for improving anaerobic threshold and performance

IL-6 Induced STAT3 Signalling Is Associated with the Proliferation of Human Muscle Satellite Cells Following Acute Muscle Damage

Although the satellite cell (SC) is a key regulator of muscle growth during development and muscle adaptation following exercise, the regulation of human muscle SC function remains largely unexplored. STAT3 signalling mediated via interleukin-6 (IL-6) has recently come to the forefront as a potential regulator of SC proliferation. The early response of the SC population in human muscle to muscle-lengthening contractions (MLC) as mediated by STAT3 has not been studied.Twelve male subjects (21±2 y; 83±12 kg) performed 300 maximal MLC of the quadriceps femoris at 180°•s(-1) over a 55° range of motion with muscle samples (vastus lateralis) and blood samples (antecubital vein) taken prior to exercise (PRE), 1 hour (T1), 3 hours (T3) and 24 hours (T24) post-exercise. Cytoplasmic and nuclear fractions of muscle biopsies were purified and analyzed for total and phosphorylated STAT3 (p-STAT3) by western blot. p-STAT3 was detected in cytoplasmic fractions across the time course peaking at T24 (p<0.01 vs. PRE). Nuclear total and p-STAT3 were not detected at appreciable levels. However, immunohistochemical analysis revealed a progressive increase in the proportion of SCs expressing p-STAT3 with ∼60% of all SCs positive for p-STAT3 at T24 (p<0.001 vs. PRE). Additionally, cMyc, a STAT3 downstream gene, was significantly up-regulated in SCs at T24 versus PRE (p<0.05). Whole muscle mRNA analysis revealed induction of the STAT3 target genes IL-6, SOCS3, cMyc (peaking at T3, p<0.05), IL-6Rα and GP130 (peaking at T24, p<0.05). In addition, Myf5 mRNA was up-regulated at T24 (p<0.05) with no appreciable change in MRF4 mRNA.We demonstrate that IL-6 induction of STAT3 signaling occurred exclusively in the nuclei of SCs in response to MLC. An increase in the number of cMyc+ SCs indicated that human SCs were induced to proliferate under the control of STAT3 signaling

The Organic Food Premium: A Local Assessment in the UK

The present study combines stated and revealed preferences in order to estimate the hypothetical bias of a sample of organic food consumers from Canterbury in the UK. It uses contingent valuation and hedonic pricing to compare stated and revealed preferences and employs the Almost Ideal Demand System to estimate the elasticity of organic products. The results show that the average price premium is fairly large (approximately 10%). They also demonstrate, crucially, that the size of this estimate is encouragingly similar whether a willingness-to-pay or hedonic pricing method is used. The estimated elasticity of organic products is on average above one, suggesting an elastic response to pricing policy in the present sample. Desirable next steps and potential policy applications for future research are also discussed

Patterns of Selection in Anti-Malarial Immune Genes in Malaria Vectors: Evidence for Adaptive Evolution in LRIM1 in Anopheles arabiensis

Co-evolution between Plasmodium species and its vectors may result in adaptive changes in genes that are crucial components of the vector's defense against the pathogen. By analyzing which genes show evidence of positive selection in malaria vectors, but not in closely related non-vectors, we can identify genes that are crucial for the mosquito's resistance against Plasmodium.We investigated genetic variation of three anti-malarial genes; CEC1, GNBP-B1 and LRIM1, in both vector and non-vector species of the Anopheles gambiae complex. Whereas little protein differentiation was observed between species in CEC1 and GNBP-B1, McDonald-Kreitman and maximum likelihood tests of positive selection show that LRIM1 underwent adaptive evolution in a primary malaria vector; An. arabiensis. In particular, two adjacent codons show clear signs of adaptation by having accumulated three out of four replacement substitutions. Furthermore, our data indicate that this LRIM1 allele has introgressed from An. arabiensis into the other main malaria vector An. gambiae.Although no evidence exists to link the adaptation of LRIM1 to P. falciparum infection, an adaptive response of a known anti-malarial gene in a primary malaria vector is intriguing, and may suggest that this gene could play a role in Plasmodium resistance in An. arabiensis. If so, our data also predicts that LRIM1 alleles in An. gambiae vary in their level of resistance against P. falciparum

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead