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S. P. Epperly 《Journal of fish biology》1989,35(1):139-152
Juvenile Atlantic menhaden, Brevoortia tyrannus , were collected from estuarine waters of the Atlantic coast of the United States. Those collected north of latitude 40°N had lower numbers of total and trunk vertebrae, ventral scutes and interhaemal spines, and shallower heads, smaller eyes, shorter predorsal lengths, and lower frequencies of the fastest allele observed at the transferrin locus than those collected south of Long Island. Although the evidence is still inconclusive, the potential for at least two subpopulations still exists: one which spawns in the spring and early summer and is responsible for the primary recruitment in the northern North Atlantic area, and one which spawns in the autumn and winter and contributes the majority of recruitment in the middle and southern North Atlantic areas of the United States. 相似文献
3.
Nuclear protein matrix was isolated from guinea pig seminal vesicle epithelium and liver. The two matrices were similar in fine structure as seen by transmission electron microscopy, in protein electropherograms, and in percent composition relative to protein, DNA, and RNA. Scanning electron microscopy was used to examine intact seminal vesicle nuclei, nuclei after treatment with Triton X-100 and DNAse I, and purified nuclear matrix. The matrix surface presented a 'porous' appearance by both scanning and transmission electron microscopy. The matrices of liver and seminal vesicle epithelium (SVE) and the intact nuclei of SVE were assayed for specific binding of free synthetic androgen, 17 alpha-methyltrienolone (R1881). Saturable specific binding was demonstrable for seminal vesicle matrix but not for liver matrix. Maximal binding of androgen occurred at a concentration of approximately 12 nM and was demonstrated to be 1.34 +/- 0.22 pmol of R1881 per mg of seminal vesicle matrix protein; the Kd was approximately 8 nM. The binding of labeled R1881 to matrix could be inhibited with low concentrations of unlabeled androgens, but not with estrogens or other steroids. Our data indicate that the binding of androgen to matrix could account for at least 21% of the binding to intact nuclei. 相似文献
4.
Abstract A class of very potent nucleoside transport inhibitors is present in two molecular forms around physiological pH. We investigated whether the monoprotonated or the unionized species of these molecules binds to this camer protein with higher affinity. 相似文献
5.
A. Daneshjoo AH. Mokhtar N. Rahnama A. Yusof 《Biology of sport / Institute of Sport》2013,30(4):281-288
The study investigates the effects of the 11+ and HarmoKnee injury prevention programmes on knee strength in male soccer players. Under-21-year-old players (n=36) were divided equally into: the 11+, HarmoKnee and control groups. The programmes were performed for 24 sessions (20-25 min each). The hamstrings and quadriceps strength were measured bilaterally at 60°·s-1, 180°·s-1 and 300°·s-1. The concentric quadriceps peak torque (PT) of the 11+ increased by 27.7% at 300°·s-1 in the dominant leg (p<0.05). The concentric quadriceps PT of HarmoKnee increased by 36.6%, 36.2% and 28% in the dominant leg, and by 31.3%, 31.7% and 20.05% at 60°·s-1, 180°·s-1 and 300°·s-1 in the non-dominant leg respectively. In the 11+ group the concentric hamstring PT increased by 22%, 21.4% and 22.1% at 60°·s-1, 180°·s-1 and 300°·s-1, respectively in the dominant leg, and by 22.3%, and 15.7% at 60°·s-1 and 180°·s-1, in the non-dominant leg. In the HarmoKnee group the hamstrings in the dominant leg showed an increase in PT by 32.5%, 31.3% and 14.3% at 60°·s-1, 180°·s-1 and 300°·s-1, and in the non-dominant leg hamstrings PT increased by 21.1% and 19.3% at 60°·s-1 and 180°·s-1 respectively. The concentric hamstrings strength was significantly different between the 11+ and control groups in the dominant (p=0.01) and non-dominant legs (p=0.02). The HarmoKnee programme enhanced the concentric strength of quadriceps. The 11+ and HarmoKnee programmes are useful warm-up protocols for improving concentric hamstring strength in young professional male soccer players. The 11+ programme is more advantageous for its greater concentric hamstring strength improvement compared to the HarmoKnee programme. 相似文献
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Alteration of the tumor microenvironment by aberrant stromal cells influences many aspects of cell biology, including differentiation of stem cells and tumor metastasis. The role of transforming growth factor (TGF)-β signaling in stromal cells of the tissue microenvironment is critical to both pathways. We examined murine marrow stromal cells with deletion of Smad3 and found that they have an altered cell cycle profile, with a higher fraction of cells in G2/M phase. Deletion of Smad3 significantly abrogates TGF-β signaling and suppresses phosphorylation of CDC27–anaphase-promoting complex (APC) during mitosis, thereby resulting in elevated cyclin-dependent kinase (CDK)1 activity via increased levels of cyclin B. Enhanced CDK1 activity due to deregulation of APC leads in turn to hyperphosphorylation of separase, impeding chromatid separation. A residue Ser1126Ala mutation in separase specifically abolished separase hyperphosphorylation in Smad3-deficient cells. The present results unveil a new function for the TGF-β pathway in the regulation of APC to mediate chromatid separation during mitosis. 相似文献
8.
Kanai A Epperly M Pearce L Birder L Zeidel M Meyers S Greenberger J de Groat W Apodaca G Peterson J 《American journal of physiology. Heart and circulatory physiology》2004,286(1):H13-H21
The existence of mitochondrial nitric oxide (NO) synthase (mtNOS) has been controversial since it was first reported in 1995. We have addressed this issue by making direct microsensor measurements of NO production in the mitochondria isolated from mouse hearts. Mitochondrial NO production was stimulated by Ca2+ and inhibited by blocking electrogenic Ca2+ uptake or by using NOS antagonists. Cardiac mtNOS was identified as the neuronal isoform by the absence of NO production in the mitochondria of mice lacking the neuronal but not the endothelial or inducible isoforms. In cardiomyocytes from dystrophin-deficient (mdx) mice, elevated intracellular Ca2+, increased mitochondrial NO production, slower oxidative phosphorylation, and decreased ATP production were detected. Inhibition of mtNOS increased contractility in mdx but not in wild-type cardiomyocytes, indicating that mtNOS may protect the cells from overcontracting. mtNOS was also implicated in radiation-induced cell damage. In irradiated rat/mouse urinary bladders, we have evidence that mitochondrially produced NO damages the urothelial "umbrella" cells that line the bladder lumen. This damage disrupts the permeability barrier thereby creating the potential to develop radiation cystitis. RT-PCR and Southern blot analyses indicate that mtNOS is restricted to the umbrella cells, which scanning electron micrographs show are selectively damaged by radiation. Simultaneous microsensor measurements demonstrate that radiation increases NO and peroxynitrite (ONOO-) production in these cells, which can be prevented by transfection with manganese superoxide dismutase (MnSOD) or instillation of NOS antagonists during irradiation or irradiation of bladders devoid of mtNOS. These studies demonstrate that mtNOS is in the cardiomyocytes and urothelial cells, that it is derived from the neuronal isoform, and that it can be either protective or detrimental. 相似文献
9.
Bowen BW Bass AL Chow SM Bostrom M Bjorndal KA Bolten AB Okuyama T Bolker BM Epperly S Lacasella E Shaver D Dodd M Hopkins-Murphy SR Musick JA Swingle M Rankin-Baransky K Teas W Witzell WN Dutton PH 《Molecular ecology》2004,13(12):3797-3808
Juvenile loggerhead turtles (Caretta caretta) from West Atlantic nesting beaches occupy oceanic (pelagic) habitats in the eastern Atlantic and Mediterranean, whereas larger juvenile turtles occupy shallow (neritic) habitats along the continental coastline of North America. Hence the switch from oceanic to neritic stage can involve a trans-oceanic migration. Several researchers have suggested that at the end of the oceanic phase, juveniles are homing to feeding habitats in the vicinity of their natal rookery. To test the hypothesis of juvenile homing behaviour, we surveyed 10 juvenile feeding zones across the eastern USA with mitochondrial DNA control region sequences (N = 1437) and compared these samples to potential source (nesting) populations in the Atlantic Ocean and Mediterranean Sea (N = 465). The results indicated a shallow, but significant, population structure of neritic juveniles (PhiST = 0.0088, P = 0.016), and haplotype frequency differences were significantly correlated between coastal feeding populations and adjacent nesting populations (Mantel test R2 = 0.52, P = 0.001). Mixed stock analyses (using a Bayesian algorithm) indicated that juveniles occurred at elevated frequency in the vicinity of their natal rookery. Hence, all lines of evidence supported the hypothesis of juvenile homing in loggerhead turtles. While not as precise as the homing of breeding adults, this behaviour nonetheless places juvenile turtles in the vicinity of their natal nesting colonies. Some of the coastal hazards that affect declining nesting populations may also affect the next generation of turtles feeding in nearby habitats. 相似文献
10.
Ben M Minogue Stephen M Richardson Leo AH Zeef Anthony J Freemont Judith A Hoyland 《Arthritis research & therapy》2010,12(1):R22