Author Keywords: Thermoregulation; convection; wind; blockage; metabolism measurement; allometry; heated taxidermic mount 相似文献
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Pyrrosia piloselloides (L.) Price is a constitutive CAM plant in the sporophytic phase of its life-cycle. Newly developed
sporophytes, still attached to the gametophytes, showed signs of CAM expression in terms of diurnal changes in titratable
acidity of the tissues. The gametophytes did not exhibit CAM.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
53.
Kristina Wallenius Tobias Kroon Therese Hagstedt Lars Löfgren Maria Sörhede-Winzell Jeremie Boucher Daniel Lindén Nicholas D. Oakes 《Journal of lipid research》2022,63(3):100176
Sodium-glucose cotransporter 2 (SGLT2) inhibitors have been shown to increase ketone bodies in patients with type 2 diabetes; however, the underlying mechanisms have not been fully elucidated. Here we examined the effect of the SGLT2 inhibitor dapagliflozin (1 mg/kg/day, formulated in a water, PEG400, ethanol, propylene glycol solution, 4 weeks) on lipid metabolism in obese Zucker rats. Fasting FFA metabolism was assessed in the anesthetized state using a [9,10-3H(N)]-palmitic acid tracer by estimating rates of plasma FFA appearance (Ra), whole-body FFA oxidation (Rox), and nonoxidative disposal (Rst). In the liver, clearance (Kβ-ox) and flux (Rβ-ox) of FFA into β-oxidation were estimated using [9,10-3H]-(R)-bromopalmitate/[U-14C]palmitate tracers. As expected, dapagliflozin induced glycosuria and a robust antidiabetic effect; treatment reduced fasting plasma glucose and insulin, lowered glycated hemoglobin, and increased pancreatic insulin content compared with vehicle controls. Dapagliflozin also increased plasma FFA, Ra, Rox, and Rst with enhanced channeling toward oxidation versus storage. In the liver, there was also enhanced channeling of FFA to β-oxidation, with increased Kβ-ox, Rβ-ox and tissue acetyl-CoA, compared with controls. Finally, dapagliflozin increased hepatic HMG-CoA and plasma β-hydroxybutyrate, consistent with a specific enhancement of ketogenesis. Since ketogenesis has not been directly measured, we cannot exclude an additional contribution of impaired ketone body clearance to the ketosis. In conclusion, this study provides evidence that the dapagliflozin-induced increase in plasma ketone bodies is driven by the combined action of FFA mobilization from adipose tissue and diversion of hepatic FFA toward β-oxidation. 相似文献
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Lili Guo Alexander A. Shestov Andrew J. Worth Kavindra Nath David S. Nelson Dennis B. Leeper Jerry D. Glickson Ian A. Blair 《The Journal of biological chemistry》2016,291(1):42-57
The antitumor agent lonidamine (LND; 1-(2,4-dichlorobenzyl)-1H-indazole-3-carboxylic acid) is known to interfere with energy-yielding processes in cancer cells. However, the effect of LND on central energy metabolism has never been fully characterized. In this study, we report that a significant amount of succinate is accumulated in LND-treated cells. LND inhibits the formation of fumarate and malate and suppresses succinate-induced respiration of isolated mitochondria. Utilizing biochemical assays, we determined that LND inhibits the succinate-ubiquinone reductase activity of respiratory complex II without fully blocking succinate dehydrogenase activity. LND also induces cellular reactive oxygen species through complex II, which reduced the viability of the DB-1 melanoma cell line. The ability of LND to promote cell death was potentiated by its suppression of the pentose phosphate pathway, which resulted in inhibition of NADPH and glutathione generation. Using stable isotope tracers in combination with isotopologue analysis, we showed that LND increased glutaminolysis but decreased reductive carboxylation of glutamine-derived α-ketoglutarate. Our findings on the previously uncharacterized effects of LND may provide potential combinational therapeutic approaches for targeting cancer metabolism. 相似文献
56.
Rae-38, a cDNA clone isolated from mouse embryonal carcinoma F9 cells, was sequenced, and the deduced RAE-38 protein showed about 86% homology to pig 3-hydroxyacyl CoA dehydrogenase (HCDH; EC 1.1.1.35). This clone can be used to elucidate the regulatory mechanism of HCDH gene expression in mammals. 相似文献
57.
George S. Bakken 《Journal of thermal biology》1990,15(3-4):207-210
1. 1.The presence of an animal in a wind tunnel increases the effective wind velocity, and so increases heat transfer rates.
2. 2.Potentially significant errors in thermal conductance and thermoregulatory metabolism measurements may result.
3. 3.In a given wind tunnel metabolism chamber, these errors are size dependent and thus may lead to invalid allometric or adaptive interpretations of data.
4. 4.The errors are also sensitive to the shape, orientation, and characteristics of the fur or feather insulation of the animal. Thus, only approximate guidelines can be given for choosing correction factors.
58.
Growth and maintenance respiration in leaves of northern red oak seedlings and mature trees after 3 years of ozone exposure 总被引:1,自引:0,他引:1
A two-component model of growth and maintenance respiration is used to study the response of northern red oak (Quercus rubra L.) seedlings and 32-year-old trees to sub-ambient (10 μmol h; cumulative dose based on 7 h daily mean), ambient (43 μmol h), and twice-ambient (85 μmolh) ozone. The relative growth rates (RGR) of leaves sampled from seedlings and trees were similar across treatments, as were specific leaf respiration rates (SRR). Growth coefficients estimated from the SRR versus RGR relationship averaged 25-3 mol CO2 kg?1 leaf dry mass produced for seedlings and 21-5 mol kg?1 for trees. Maintenance coefficients ranged from 0-89 to 1-07 mol CO2 kg?1 leaf dry mass d?1 for seedlings and from 0-64 to 0-84 mol kg-1 d?1 for trees. Neither coefficient was affected by ozone. Leaves sampled throughout the growing season also showed little response of respiration to ozone. This occurred despite a 30% reduction in net photosynthesis for trees grown at twice-ambient ozone. These results suggest that growth and maintenance respiration in young northern red oak leaves are not affected by ozone and that in older leaves injury can occur without a parallel increase in so-called ‘maintenance’ respiration. 相似文献
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