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81.
82.
Jacks DE Sowash J Anning J McGloughlin T Andres F 《Journal of strength and conditioning research / National Strength & Conditioning Association》2002,16(2):286-289
Changes in cortisol concentration in response to exercise at 3 different intensities were quantified. Ten apparently healthy, recreationally active males participated. On 4 separate occasions, subjects were assigned a random order of 1-hour cycle ergometer bouts of exercise at 44.5 +/- 5.5%, 62.3 +/- 3.8%, and 76.0 +/- 6.0% (mean +/- SD) of VO2peak and a resting control session. Saliva samples were collected before exercise at 10, 20, 40, and 59 minutes of exercise and at 20 minutes of recovery. Differences in cortisol concentration were assessed via multivariate analysis of variance (alpha = 0.05) Tukey post hoc analysis when indicated. During the highest-intensity exercise session, cortisol was significantly higher at 59 minutes of exercise (p = 0.004) and at 20 minutes of recovery (p = 0.016) than at those same time points during the resting control session. No significant differences in cortisol concentration were noted among resting, low-, and moderate-intensity exercise. Exercise <40 minutes in duration elicited no significant differences at any intensity. These data indicate that only exercise of high intensity and long duration results in significant elevations of salivary cortisol. 相似文献
83.
Comprehensive gene expression analysis by transcript profiling 总被引:20,自引:0,他引:20
Donson J Fang Y Espiritu-Santo G Xing W Salazar A Miyamoto S Armendarez V Volkmuth W 《Plant molecular biology》2002,48(1-2):75-97
84.
85.
We have investigated the role in the fold and RNA-binding properties of the KH modules of a hydrophobic to asparagine mutation of clinical importance in the fragile X syndrome. The mutation involves a well-conserved hydrophobic residue close to the N terminus of the second helix of the KH fold (alpha2(3) position). The effect of the mutation has been long debated: Although the mutant has been shown to disrupt the three-dimensional fold of several KH domains, the residue seems also to be directly involved in RNA binding, the main function of the KH module. Here we have used the KH3 of Nova-1, whose structure is known both in isolation and in an RNA complex, to study in detail the role of the alpha2(3) position. A detailed comparison of Nova KH3 structure with its RNA/KH complex and with other KH structures suggests a dual role for the alpha2(3) residue, which is involved both in stabilizing the hydrophobic core and in RNA contacts. We further show by nuclear magnetic resonance (NMR) studies in solution that L447 of Nova-1 in position alpha2(3) is in exchange in the absence of RNA, and becomes locked in a more rigid conformation only upon formation of an RNA complex. This implies that position alpha2(3) functions as a "gate" in the mechanism of RNA recognition of KH motifs based on the rigidification of the fold upon RNA binding. 相似文献
86.
The mechanical stability of ubiquitin is linkage dependent 总被引:12,自引:0,他引:12
Carrion-Vazquez M Li H Lu H Marszalek PE Oberhauser AF Fernandez JM 《Nature structural biology》2003,10(9):738-743
Ubiquitin chains are formed through the action of a set of enzymes that covalently link ubiquitin either through peptide bonds or through isopeptide bonds between their C terminus and any of four lysine residues. These naturally occurring polyproteins allow one to study the mechanical stability of a protein, when force is applied through different linkages. Here we used single-molecule force spectroscopy techniques to examine the mechanical stability of N-C-linked and Lys48-C-linked ubiquitin chains. We combined these experiments with steered molecular dynamics (SMD) simulations and found that the mechanical stability and unfolding pathway of ubiquitin strongly depend on the linkage through which the mechanical force is applied to the protein. Hence, a protein that is otherwise very stable may be easily unfolded by a relatively weak mechanical force applied through the right linkage. This may be a widespread mechanism in biological systems. 相似文献
87.
Kriete A Anderson MK Love B Freund J Caffrey JJ Young MB Sendera TJ Magnuson SR Braughler JM 《Genome biology》2003,4(5):R32
We have developed a unique methodology for the combined analysis of histomorphometric and gene-expression profiles amenable to intensive data mining and multisample comparison for a comprehensive approach to toxicology. This hybrid technology, termed extensible morphometric relational gene-expression analysis (EMeRGE), is applied in a toxicological study of time-varied vehicle- and carbon-tetrachloride (CCl4)-treated rats, and demonstrates correlations between specific genes and tissue structures that can augment interpretation of biological observations and diagnosis. 相似文献
88.
89.
The rate of expansion of bacterial colonies of S. liquefaciens is investigated in terms of a mathematical model that combines biological as well as hydrodynamic processes. The relative
importance of cell differentiation and production of an extracellular wetting agent to bacterial swarming is explored using
a continuum representation. The model incorporates aspects of thin film flow with variable suspension viscosity, wetting,
and cell differentiation. Experimental evidence suggests that the bacterial colony is highly sensitive to its environment
and that a variety of mechanisms are exploited in order to proliferate on a variety of surfaces. It is found that a combination
of effects are required to reproduce the variation of bacterial colony motility over a large range of nutrient availability
and medium hardness.
Received: 29 April 1999 相似文献
90.
Andres M Lozano Anthony E Lang William D Hutchison Jonathon O Dostrovsky 《Current opinion in neurobiology》1998,8(6):783-790
Important recent advances have been made in understanding the etiology and pathogenesis of Parkinson's disease, as well as in developing novel treatments. Two newly identified genes, α-synuclein and parkin, have been linked to parkinsonism. In addition, disturbances to the normal basal ganglia circuits in Parkinson's patients are being described at both anatomical and physiological levels. These developments provide a strong scientific basis for novel medical and surgical strategies to treat the profound motor disturbances in patients with Parkinson's disease. 相似文献