The influence of volume of exercise on early adaptations to strength training

The purpose of this investigation was to compare the effects of single-set strength training and 3-set strength training during the early phase of adaptation in 18 untrained male subjects (age, 20-30 years). After initial testing, subjects were randomly assigned to either the 3L-1U group (n = 8), which trained 3 sets in leg exercises and 1 set in upper-body exercises, or the 1L-3U group (n = 10), which trained 1 set in leg exercises and 3 sets in upper-body exercises. Testing was conducted at the beginning and at the end of the study and consisted of 2 maximal isometric tests (knee extension and bench press) and 6 maximal dynamic tests (1 repetition maximum [1RM] tests). Subjects trained 3 days per week for 6 weeks. After warm-up, subjects performed 3 leg exercises and 4 upper-body exercises. In both groups, each set consisted of 7 repetitions (reps) with the load supposed to induce muscular failure after the seventh rep (7RM load). After 6 weeks of training, 1RM performance in all training exercises was significantly increased (10-26%, p < 0.01) in both groups. The relative increase in 1RM load in the 3 leg exercises was significantly greater in the 3L-1U group than in the 1L-3U group (21% vs. 14%, p = 0.01). However, the relative increase in 1RM load in the 3 upper-body exercises was similar in the 3L-1U group (16%) and the 1L-3U group (14%). These results show a superior adaptation to 3-set strength training, compared with 1-set strength training, in leg exercises but not in upper-body exercises during the early phase of adaptation.     

Comparative genomics of <Emphasis Type="Italic">Lactobacillus sakei</Emphasis> with emphasis on strains from meat

Lactobacillus sakei is a lactic acid bacterium important in food microbiology mainly due to its ability to ferment and preserve meat. The genome sequence of L. sakei strain 23K has revealed specialized metabolic capacities that reflect the bacterium’s adaption to meat products, and that differentiate it from other LAB. An extensive genomic diversity analysis was conducted to elucidate the core features of the species, and to provide a better comprehension of niche adaptation of the organism. Here, we describe the genomic comparison of 18 strains of L. sakei originating mainly from processed meat against the 23K strain by comparative genome hybridization. Pulsed field gel electrophoresis was used to estimate the genome sizes of the strains, which varied from 1.880 to 2.175 Mb, and the 23K genome was among the smallest. Consequently, a large part of the genome of this strain belongs to a common gene pool invariant in this species. The majority of genes important in adaption to meat products, the ability to flexibly use meat components, and robustness during meat processing and storage were conserved, such as genes involved in nucleoside scavenging, catabolism of arginine, and the ability to cope with changing redox and oxygen levels, which is indicative of the role these genes play in niche specialization within the L. sakei species. Moreover, an additional set of sequenced L. sakei genes beyond the 23K genome was present on the microarray used, and it was demonstrated that all the strains carry remnants of or complete bacteriocin operons. The genomic divergence corresponded mainly to five regions in the 23K genome, which showed features consistent with horizontal gene transfer. Carbohydrate-fermentation profiles of the strains were evaluated in light of the CGH data, and for most substrates, the genotypes were consistent with the phenotypes. We have demonstrated a highly conserved organization of the L. sakei genomes investigated, and the 23K strain is a suitable model organism to study core features of the L. sakei species.     

A heterogeneous computing environment to solve the 768-bit RSA challenge

In December 2009 the 768-bit, 232-digit number RSA-768 was factored using the number field sieve. Overall, the computational challenge would take more than 1700 years on a single, standard core. In the article we present the heterogeneous computing approach, involving different compute clusters and Grid computing environments, used to solve this problem.     

Impact of two myostatin (MSTN) mutations on weight gain and lamb carcass classification in Norwegian White Sheep (Ovis aries)

Background

Our aim was to estimate the effect of two myostatin (MSTN) mutations in Norwegian White Sheep, one of which is close to fixation in the Texel breed.

Methods

The impact of two known MSTN mutations was examined in a field experiment with Norwegian White Sheep. The joint effect of the two MSTN mutations on live weight gain and weaning weight was studied on 644 lambs. Carcass weight gain from birth to slaughter, carcass weight, carcass conformation and carcass fat classes were calculated in a subset of 508 lambs. All analyses were carried out with a univariate linear animal model.

Results

The most significant impact of both mutations was on conformation and fat classes. The largest difference between the genotype groups was between the wild type for both mutations and the homozygotes for the c.960delG mutation. Compared to the wild types, these mutants obtained a conformation score 5.1 classes higher and a fat score 3.0 classes lower, both on a 15-point scale.

Conclusions

Both mutations reduced fatness and increased muscle mass, although the effect of the frameshift mutation (c.960delG) was more important as compared to the 3''-UTR mutation (c.2360G>A). Lambs homozygous for the c.960delG mutation grew more slowly than those with other MSTN genotypes, but had the least fat and the largest muscle mass. Only c.960delG showed dominance effects.     

Dendritic Cells Loaded with Tumor Antigens and a Dual Immunostimulatory and Anti-Interleukin 10-Specific Small Interference RNA Prime T Lymphocytes against Leukemic Cells

Vaccines using dendritic cells (DCs) harboring leukemic antigens to stimulate T cells is a possible treatment of acute myeloid leukemia (AML). Limitations of breaking tolerance to leukemic cells and lack of specific activation of T cell-mediated cytotoxicity may explain the discouraging clinical results with this approach. To break self-tolerance against AML cells, we loaded DCs with AML antigens and a bifunctional small interference (si) RNA targeting interleukin (IL) 10 and simultaneously activating toll-like receptors (TLRs). In vitro, this active siRNA inhibited (P < .05) IL-10 production by silencing the IL-10 gene in DCs. The active siRNA stimulated production of tumor necrosis factor α, implying activation of TLRs. Vaccination in a nonimmunogenic rat model mimicking human AML with the loaded DCs induced a substantial and specific T-cell cytotoxicity. Leukemic rats treated with the active siRNA lived longer and had markedly less leukemic cell mass infiltrating their bone marrow compared with rats given inactive siRNA (P < .05). Furthermore, compared with inactive siRNA treatment, the active siRNA led to significantly less extramedullar leukemic dissemination, evidenced by reduced matrix metalloproteinase activity and smaller spleens. Our data demonstrate that this bifunctional siRNA may work as an immunomodulatory drug with antileukemic properties.     

Circumpolar analysis of morphological and genetic diversity in the Notostracan Lepidurus arcticus

This study presents a first circumpolar screening of the taxonomic and genetic diversity of the crustacean Lepidurus arcticus, belonging to the ‘living fossil’ order Notostraca. Sequencing of a 484 bp segment of the mitochondrial 12S rDNA from 48 populations revealed two distinct haplogroups, each consisting of separate haplotypes. Alignment with published sequences of other species of Lepidurus clearly revealed that all of the studied populations were distinctly different from other species. Some major geographical patterns for distribution of haplogroups and haplotypes were identified, perhaps the most remarkable being the difference in distribution of haplogroups between the neighbouring Svalbard and Bear Island where a larger number of populations were studied. On the Norwegian mainland both haplogroups co-occurred in the same areas, however, and strong conclusions of the distributional pattern are yet premature. The distribution of similar haplotypes over wide geographical ranges suggests high dispersal abilities by Lepidurus. Morphological taxonomic criteria assign all surveyed populations to L. arcticusin spite of a pronounced morphological plasticity. Analysis of major morphological features such as length:width ratio of cephalothorax, the cephalothorax:abdominal length ratio, size of supra-anal plate and eye morphology revealed some distinctive population specific properties. The two major haplogroups differed significantly with regard to the relative size of the supra-anal plate, which also is a standard taxonomic criterion. This first genetic screening of a limited number of populations suggests that a subtler genetic diversity will be revealed when including more populations over a larger geographic area as well as a finer geographical resolution.     

Seasonal seston stoichiometry: effects on zooplankton in cyanobacteria-dominated lakes

Seasonal dynamics in elemental composition [carbon (C), nitrogenand phosphorus (P)] of seston and zooplankton were studied overseveral years in three hypereutrophic Dutch lakes with persistentdominance and high biomass of cyanobacteria. In all three lakes,there was a strong pattern with decreased P-content and increasedC:P ratio in seston (<150 µm) coinciding with the increasein water temperature. The seston C:P ratios (at:at) were morethan doubled with the rising temperature, i.e. from 200 (at:at)in winter to 500 in summer. Sestonic C:P ratios increased overthe growing season, suggesting that seasonal dynamics amongautotrophs with high P-uptake in winter and support of subsequentphytoplankton growth by consumption of internal cellular P (P-quota)was the main cause of low sestonic P contents in late summer.This could, however, occur in concert with a physiologicallydriven decrease in cell-specific P at higher temperatures insummer. In contrast, the annual variation of C:P ratios of thezooplankton fraction was only 10% of that of seston. The variationsof C:P ratios of the zooplankton were, nevertheless, stronglycorrelated with those of seston. For most of the summer, sestonC:P ratios were far above the threshold ratio for P-limitationin Daphnia and other P-demanding species. This will pose furtherconstraints on growth performance of Daphnia in these lakes,thus adding to the fish predation pressure and the poor foodquality of cyanobacteria per se. The low grazing pressure causesa high biomass of low-quality autotrophs, promoting a stablestate with low trophic transfer efficiency.     

Molecular and Genetic Characterization of Propionicin F, a Bacteriocin from Propionibacterium freudenreichii

This work describes the purification and characterization of propionicin F, the first bacteriocin isolated from Propionibacterium freudenreichii. The bacteriocin has a bactericidal activity and is only active against strains of P. freudenreichii. Propionicin F appears to be formed through a processing pathway new to bacteriocins. The mass of the purified bacteriocin was determined by mass spectrometry, and the N-terminal amino acid sequence was determined by Edman degradation. Sequencing of pcfA, the bacteriocin structural gene, revealed that propionicin F corresponds to a 43-amino-acid peptide in the central part of a 255-amino-acid open reading frame, suggesting that mature propionicin F is excised from the probacteriocin by N- and C-terminal proteolytic modifications. DNA sequencing and Northern blot hybridizations revealed that pcfA is cotranscribed with genes encoding a putative proline peptidase and a protein from the radical S-adenosylmethionine family. A gene encoding an ABC transporter was also identified in close proximity to the bacteriocin structural gene. The potential role of these genes in propionicin F maturation and secretion is discussed.