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Peveler WW Bishop PA Whitehorn EJ 《Journal of strength and conditioning research / National Strength & Conditioning Association》2006,20(3):519-522
The amount of adenosine triphosphate (ATP) stored in the muscle available for immediate use is limited, and once used, must be resynthesized in the muscle. Ribose, a naturally occurring pentose sugar, helps resynthesize ATP for use in muscles. There have been claims that ribose supplements increase ATP levels and improve performance. Other studies have provided mixed results on the effectiveness of ribose as an ergogenic aid at high doses. None of these studies have compared the impact of the recommended dose of ribose on athletes and nonathletes under exercise conditions that are most conducive for effectiveness. The purpose of this study was to evaluate the effectiveness of ribose as an ergogenic aid at the dose recommended for supplements currently on the market during an exercise trial to maximize its efficacy. Male subjects (n = 11) performed 2 trials 1 week apart. Each trial consisted of three 30-second Wingate tests with a 2-minute recovery between each test. Trials were counterbalanced, with 1 trial being performed with 625 mg of ribose and the other with a placebo. Peak power, mean power, and percent decrease in power were recorded during each Wingate test. Repeated-measures analysis of variance (p > 0.05) found no significant differences between ribose and placebo. These results suggest that ribose had no effect on performance when taken orally, at the dose suggested by the distributor. 相似文献
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Johnson MS Bolick A Alexander M Huffman D Oborny E Monroe A 《The Journal of parasitology》2012,98(1):111-116
Centrocestus formosanus (Trematoda: Heterophyidae) is an invasive fish parasite in the Comal River, Texas, and is considered a threat to the federally endangered fountain darter, Etheostoma fonticola . Monitoring densities of C. formosanus cercariae is crucial to determining levels of infection pressure. We sampled 3 sites in the Comal River during 2 sampling periods, the first during 2006-2007, and again during 2009-2010. Two of the sites were located in the upstream reach of Landa Lake, sites HS and LA, and the third site was located downstream of Landa Lake in the old channel of the river. Cercariae densities were highest at the downstream most site (EA), followed by sites LA and HS, during both sampling periods, but a significant decline in cercariae density was observed between the first and second sampling periods. Several abiotic factors were monitored, including total stream discharge, wading discharge, temperature, and dissolved oxygen, but no river-wide trends were observed. Therefore, we speculate that these factors do not adequately explain the observed long-term decline in cercariae density. We propose that the decline is simply a reflection of a typical pattern followed by most invasive species as they gradually become integrated into the local community following an initial explosive growth in population size. Although cercariae densities may be abating, fountain darters in the Comal River are still threatened by the parasite, and conservation efforts must focus on reducing levels of infection pressure from the parasite whenever possible. 相似文献
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Suzanne S. Stokes Robert Albert Ed T. Buurman Beth Andrews Adam B. Shapiro Oluyinka M. Green Andrew R. McKenzie Ludovic R. Otterbein 《Bioorganic & medicinal chemistry letters》2012,22(23):7019-7023
A previously described aryl sulfonamide series, originally found through HTS, targets GlmU, a bifunctional essential enzyme involved in bacterial cell wall synthesis. Using structure-guided design, the potency of enzyme inhibition was increased in multiple isozymes from different bacterial species. Unsuitable physical properties (low Log D and high molecular weight) of those compounds prevented them from entering the cytoplasm of bacteria and inhibiting cell growth. Further modifications described herein led to compounds that possessed antibacterial activity, which was shown to occur through inhibition of GlmU. The left-hand side amide and the right-hand side sulfonamides were modified such that enzyme inhibitory activity was maintained (IC50 <0.1 μM against GlmU isozymes from Gram-negative organisms), and the lipophilicity was increased giving compounds with Log D ?1 to 3. Antibacterial activity in an efflux-pump deficient mutant of Haemophilus influenzae resulted for compounds such as 13. 相似文献
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Vrisekoop N van Gent R de Boer AB Otto SA Borleffs JC Steingrover R Prins JM Kuijpers TW Wolfs TF Geelen SP Vulto I Lansdorp P Tesselaar K Borghans JA Miedema F 《Journal of immunology (Baltimore, Md. : 1950)》2008,181(2):1573-1581
It remains uncertain whether full T cell reconstitution can be established in HIV-infected children and adults with long-term sustained virological control by highly active antiretroviral therapy (HAART). In this study, we comprehensively analyzed various phenotypical markers of CD4 T cell recovery. In addition to measuring T cell activation and proliferation markers, CD4 T cell generation and aging of the CD4 T cell compartment were assessed by measuring TCR excision circles and the fraction of CD31-expressing naive CD4 T cells. In all children and in adults with relatively high CD4 T cell counts at start of therapy (>200 cells/microl), total CD4 T cell numbers normalized within 1 year of therapy. After long-term HAART (4.4-9.6 years), naive CD4 T cell counts had normalized in both groups. Although in adults with low baseline CD4 T cell counts (<200 cells/microl) total CD4 T cell numbers normalized eventually after at least 7 years of HAART, naive CD4 T cell counts had still not recovered. TCR excision circle data showed that thymic T cell production contributed to naive T cell recovery at all ages. The fraction of CD31-expressing naive CD4 T cells was found to be normal, suggesting that the CD4 T cell repertoire was diverse after long-term HAART. Hence, under sustained viral suppression during long-term HAART, the T cell compartment has the potential to fully recover by generating new naive T cells both in children and in adults with high baseline CD4 T cells counts. Irrespective of baseline CD4 T cell counts, reconstitution occurred without a significant effect on T cell aging as reflected by markers for replicative history. 相似文献
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RNase-based self-incompatibility: puzzled by pollen S 总被引:1,自引:0,他引:1
Many plants have a genetically determined self-incompatibility system in which the rejection of self pollen grains is controlled by alleles of an S locus. A common feature of these S loci is that separate pollen- and style-expressed genes (pollen S and style S, respectively) determine S allele identity. The long-held view has been that pollen S and style S must be a coevolving gene pair in order for allelic recognition to be maintained as new S alleles arise. In at least three plant families, the Solanaceae, Rosaceae, and Plantaginaceae, the style S gene has long been known to encode an extracellular ribonuclease called the S-RNase. Pollen S in these families has more recently been identified and encodes an F-box protein known as either SLF or SFB. In this perspective, we describe the puzzling evolutionary relationship that exists between the SLF/SFB and S-RNase genes and show that in most cases cognate pairs of genes are not coevolving in the expected manner. Because some pollen S genes appear to have arisen much more recently than their style S cognates, we conclude that either some pollen S genes have been falsely identified or that there is a major problem with our understanding of how the S locus evolves. 相似文献
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