The ameliorative effect of fulvic acid(0, 300, and 600 mg L-1) on photosystem II and antioxidant enzyme activity of the rapeseed(Brassica napus L.) plant under water stress(60, 100, and 140 mm evaporation from class A...The ameliorative effect of fulvic acid(0, 300, and 600 mg L-1) on photosystem II and antioxidant enzyme activity of the rapeseed(Brassica napus L.) plant under water stress(60, 100, and 140 mm evaporation from class A pan) was studied using split plots in a randomized complete block design with three replications. Results indicated that application of fulvic acid(FA) improved the maximum quantum efficiency of PSII(Fv/Fm)and performance index(PI) of plants under both well-watered and limited-water conditions. The time span from Foto Fmand the energy necessary for the closure of all reaction centers was significantly increased, but the size of the plastoquinone pool was reduced with increasing water stress levels. Plants treated with FA had higher peroxidase and catalase activities under all irrigation conditions. Activities of ascorbate peroxidase and superoxide dismutase in plants increased with increasing water stress. Malondialdehyde increased under severe water stress, but application of FA significantly decreased lipid peroxidation. Production of reactive oxygen species(ROS) is a common phenomenon in plants under stress. Under this condition, the balance between the production of ROS and the quenching activity of antioxidants is upset, often resulting in oxidative damage. In this study, application of FA significantly increased fluorescence of chlorophyll a, inhibiting ROS production and enhancing antioxidant enzymes activity that destroyed ROS. Thus, ROS in plant cells was reduced under water stress by application of FA and consequently lipid peroxidation was reduced.展开更多
Ablotlc stresses, such as drought, high salinity, and cold/freezing, lead plants to produce excess reactive oxygen species. Catalase, a unique hydrogen peroxide-scavenging enzyme, plays a very Important role In plants...Ablotlc stresses, such as drought, high salinity, and cold/freezing, lead plants to produce excess reactive oxygen species. Catalase, a unique hydrogen peroxide-scavenging enzyme, plays a very Important role In plants. To characterize the catalase involved In plant response to ablotlc stresses, we constructed a cDNA library from 4℃-treated Festuca arundinacea Schreb seedlings and isolated a catalase gene from this library. The cDNA （FaCat1, 1 735 bp） contained an open reading frame of 1 479 bp. BLAST analysis Indicated that the deduced amino acid sequence showed 96% Identity with that from wheat TaCat1 and 87% Identity with that from maize ZmCat2. Northern blotting analysis showed an obvious Increase of FaCat1 transcripts In leaves In contrast with roots. Time-course analysis of the expression of FaCat1 in F. arundinacea leaves showed that FaCat1 expression was upregulated in cold- and salt-stressed leaves, with the FaCat1 transcripts accumulat-Ing mostly at 4 or 2 h after cold or salt stress, respectively. No significant changes in FaCat1 transcription were observed in dried leaves and inhibition of FaCat1 transcription was found In absclsic acid （ABA）-treated leaves, Indicating that the FaCat1 gene is differentially expressed during cold, high salt, drought, and ABA treatment In F. arundinacea leaves.展开更多
Activating transcription factor 4 （ATF4） has been shown to play key roles in many physiological processes. There are no reports, however, demonstrating a direct link between ATF4 and lipid metabolism. We noticed tha...Activating transcription factor 4 （ATF4） has been shown to play key roles in many physiological processes. There are no reports, however, demonstrating a direct link between ATF4 and lipid metabolism. We noticed that Atf4- deficient mice are lean, suggesting a possible role for ATF4 in regulating lipid metabolism. The goal of our current study is to investigate the involvement of ATF4 in lipid metabolism and elucidate the underlying mechanisms. Studies using Atf4-deficient mice revealed increased energy expenditure, as measured by oxygen consumption. These mice also showed increases in lipolysis, expression of uncoupling protein 2 （UCP2） and p-oxidation genes and decreases in expression of lipogenic genes in white adipose tissue （WAT）, suggesting increased utilization and decreased synthesis of fatty acids, respectively. Expression of UCP1, 2 and 3 was also increased in brown adipose tissue （BAT）, suggesting increased thermogenesis. The effect of ATF4 deletion on expression of UCPs in BAT suggests that increased thermogenesis may underlie increased energy expenditure. Thus, our study identifies a possible new function for ATF4 in regulating lipid metabolism and thermogenesis.展开更多
Wax deposits on the wall of a crude oil pipeline are a solid wax network of fine crystals, filled with oil, resin, asphaltene and other impurities. In this paper, a series of experiments on wax deposition in a laborat...Wax deposits on the wall of a crude oil pipeline are a solid wax network of fine crystals, filled with oil, resin, asphaltene and other impurities. In this paper, a series of experiments on wax deposition in a laboratory flow loop were performed under different conditions （flow rate, temperature differential between crude oil and pipeline wall, and dissolved wax concentration gradient）, and the wax deposits were analyzed, so quantitative relationships among wax content, wax appearance temperature （WAT）, shear stress, and radial concentration gradient of dissolved wax at the solid/liquid interface were obtained. Finally, a model was established to predict WAT and the wax content of the deposit.展开更多
In plastic and reconstructive surgery there is an increasing demand for malleable implants to repair soft tissue congenital defects, or those resulting from aging, traumatic injury and tumour resection. However, curre...In plastic and reconstructive surgery there is an increasing demand for malleable implants to repair soft tissue congenital defects, or those resulting from aging, traumatic injury and tumour resection. However, currently available methods present a number of limitations such as volume loss over time and eventual resorption of the graft. Tissue engineering techniques provide promising therapeutic solutions to these inconveniences through development of engineered equivalents that best imitate adipose tissue, both structurally and functionally. Here we review the latest achievements in the human adipose tissue engineering field, with a focus on its regenerative potential for a number of clinical applications.展开更多
文摘The ameliorative effect of fulvic acid(0, 300, and 600 mg L-1) on photosystem II and antioxidant enzyme activity of the rapeseed(Brassica napus L.) plant under water stress(60, 100, and 140 mm evaporation from class A pan) was studied using split plots in a randomized complete block design with three replications. Results indicated that application of fulvic acid(FA) improved the maximum quantum efficiency of PSII(Fv/Fm)and performance index(PI) of plants under both well-watered and limited-water conditions. The time span from Foto Fmand the energy necessary for the closure of all reaction centers was significantly increased, but the size of the plastoquinone pool was reduced with increasing water stress levels. Plants treated with FA had higher peroxidase and catalase activities under all irrigation conditions. Activities of ascorbate peroxidase and superoxide dismutase in plants increased with increasing water stress. Malondialdehyde increased under severe water stress, but application of FA significantly decreased lipid peroxidation. Production of reactive oxygen species(ROS) is a common phenomenon in plants under stress. Under this condition, the balance between the production of ROS and the quenching activity of antioxidants is upset, often resulting in oxidative damage. In this study, application of FA significantly increased fluorescence of chlorophyll a, inhibiting ROS production and enhancing antioxidant enzymes activity that destroyed ROS. Thus, ROS in plant cells was reduced under water stress by application of FA and consequently lipid peroxidation was reduced.
文摘Ablotlc stresses, such as drought, high salinity, and cold/freezing, lead plants to produce excess reactive oxygen species. Catalase, a unique hydrogen peroxide-scavenging enzyme, plays a very Important role In plants. To characterize the catalase involved In plant response to ablotlc stresses, we constructed a cDNA library from 4℃-treated Festuca arundinacea Schreb seedlings and isolated a catalase gene from this library. The cDNA （FaCat1, 1 735 bp） contained an open reading frame of 1 479 bp. BLAST analysis Indicated that the deduced amino acid sequence showed 96% Identity with that from wheat TaCat1 and 87% Identity with that from maize ZmCat2. Northern blotting analysis showed an obvious Increase of FaCat1 transcripts In leaves In contrast with roots. Time-course analysis of the expression of FaCat1 in F. arundinacea leaves showed that FaCat1 expression was upregulated in cold- and salt-stressed leaves, with the FaCat1 transcripts accumulat-Ing mostly at 4 or 2 h after cold or salt stress, respectively. No significant changes in FaCat1 transcription were observed in dried leaves and inhibition of FaCat1 transcription was found In absclsic acid （ABA）-treated leaves, Indicating that the FaCat1 gene is differentially expressed during cold, high salt, drought, and ABA treatment In F. arundinacea leaves.
文摘Activating transcription factor 4 （ATF4） has been shown to play key roles in many physiological processes. There are no reports, however, demonstrating a direct link between ATF4 and lipid metabolism. We noticed that Atf4- deficient mice are lean, suggesting a possible role for ATF4 in regulating lipid metabolism. The goal of our current study is to investigate the involvement of ATF4 in lipid metabolism and elucidate the underlying mechanisms. Studies using Atf4-deficient mice revealed increased energy expenditure, as measured by oxygen consumption. These mice also showed increases in lipolysis, expression of uncoupling protein 2 （UCP2） and p-oxidation genes and decreases in expression of lipogenic genes in white adipose tissue （WAT）, suggesting increased utilization and decreased synthesis of fatty acids, respectively. Expression of UCP1, 2 and 3 was also increased in brown adipose tissue （BAT）, suggesting increased thermogenesis. The effect of ATF4 deletion on expression of UCPs in BAT suggests that increased thermogenesis may underlie increased energy expenditure. Thus, our study identifies a possible new function for ATF4 in regulating lipid metabolism and thermogenesis.
文摘Wax deposits on the wall of a crude oil pipeline are a solid wax network of fine crystals, filled with oil, resin, asphaltene and other impurities. In this paper, a series of experiments on wax deposition in a laboratory flow loop were performed under different conditions （flow rate, temperature differential between crude oil and pipeline wall, and dissolved wax concentration gradient）, and the wax deposits were analyzed, so quantitative relationships among wax content, wax appearance temperature （WAT）, shear stress, and radial concentration gradient of dissolved wax at the solid/liquid interface were obtained. Finally, a model was established to predict WAT and the wax content of the deposit.
文摘In plastic and reconstructive surgery there is an increasing demand for malleable implants to repair soft tissue congenital defects, or those resulting from aging, traumatic injury and tumour resection. However, currently available methods present a number of limitations such as volume loss over time and eventual resorption of the graft. Tissue engineering techniques provide promising therapeutic solutions to these inconveniences through development of engineered equivalents that best imitate adipose tissue, both structurally and functionally. Here we review the latest achievements in the human adipose tissue engineering field, with a focus on its regenerative potential for a number of clinical applications.
