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311.
Lipoprotein lipase (LPL) plays a critical role in the metabolism of plasma lipoproteins. In 3T3-L1 adipocytes, insulin elicits the rapid release of LPL through mechanisms that are independent of energy metabolism and protein synthesis. Some of the metabolic actions of insulin may be mediated by the activation of a specific phospholipase that hydrolyzes a glycosyl phosphatidylinositol (PI) molecule. The insulin-sensitive glycosyl-PI is structurally similar to the glycolipid membrane anchor of a number of proteins. LPL appears to be anchored to the 3T3-L1 cell surface by glycosyl-PI, and its rapid release by insulin may be due to activation of a glycosyl-PI-specific phospholipase C.  相似文献   
312.
Oncogenic CARD11 mutations in human diffuse large B cell lymphoma   总被引:1,自引:0,他引:1  
Diffuse large B cell lymphoma (DLBCL) is the most common form of non-Hodgkin's lymphoma. In the least curable (ABC) subtype of DLBCL, survival of the malignant cells is dependent on constitutive activation of the nuclear factor-kappaB (NF-kappaB) signaling pathway. In normal B cells, antigen receptor-induced NF-kappaB activation requires CARD11, a cytoplasmic scaffolding protein. To determine whether CARD11 contributes to tumorigenesis, we sequenced the CARD11 gene in human DLBCL tumors. We detected missense mutations in 7 of 73 ABC DLBCL biopsies (9.6%), all within exons encoding the coiled-coil domain. Experimental introduction of CARD11 coiled-coil domain mutants into lymphoma cell lines resulted in constitutive NF-kappaB activation and enhanced NF-kappaB activity upon antigen receptor stimulation. These results demonstrate that CARD11 is a bona fide oncogenein DLBCL, providing a genetic rationale for the development of pharmacological inhibitors of the CARD11 pathway for DLBCL therapy.  相似文献   
313.
The present study was to examine effect of soy leaf powder (SLP) and soy leaf ethanol extract (SLEE) on serum lipoproteins in hamsters. The control group was fed a semisynthetic diet containing 0.1% cholesterol, while the tested groups were maintained on the same diet but supplemented with 3% SLP or the equivalent amount of SLEE derived from 3% SLP for 4 weeks. SLP supplementation led to a trend of lowering serum total cholesterol (TC) and nonhigh density lipoprotein cholesterol (non-HDL-C), with HDL-C being unaffected, whereas incorporation of SLEE into the diet led to an elevated level of HDL-C and a lower level of non-HDL-C with TC being unchanged. Both SLP and SLEE supplementation caused favorably a decrease in the ratio of non-HDL-C to HDL-C. The present results demonstrate that not only soybean seeds but also soy leaves are cardioprotective, by favorably modulating serum lipid profile.  相似文献   
314.
Nitrogen (N) removal within reservoirs can be substantial, but few studies have reported the relative importance of various N-retention pathways. Assessing N-removal processes in reservoirs is important for quantifying the impacts of reservoirs on downstream water quality. In this study, we used a time-series approach to quantify the relative importance of various N-removal processes in the Saylorville Reservoir in Iowa. Dynamic regression modeling of upstream–downstream changes in key water-quality surrogates (pH, hardness, alkalinity, and suspended solids) and their relation to N concentration changes were used to estimate the relative importances of denitrification, N assimilation by algal uptake, and sedimentation of N on N retention in the reservoir. Assuming that decreasing N concentrations in the reservoir are the sum of these three processes, we estimate that denitrification is the dominant N removal process (60.9 %) followed by algal assimilation (37.9 %) and sedimentation (1.2 %). Our approach represents a new method of establishing the relative importance of N-removal processes in reservoirs and quantifying the impacts of reservoirs on downstream water quality.  相似文献   
315.
This study dealt with a restoration project conducted at South‐East New Territories Landfill in Hong Kong, in order to screen suitable tree and shrub species (both native and pioneer species) for revegetation. For engineered landfills, landfill gas migration and leachate contamination to the topsoil are rarely problematic, but the lack of nutrients and moisture and poor physical soil conditions may jeopardize potential woodland establishment. The growth performance of 25 woody plant species subjected to 12 different soil amelioration and seedlings planting methods was compared. The results showed that the general performance (mortality rate, apical height, crown diameter and basal diameter) of pioneer species (notably Acacia species) was much better than that of native species in all blocks of woodland mix and scrub mix. The notch planting method was effective in helping seedling roots to have better contact with soil for water uptake, which subsequently increased the survival rates of seedlings, leading to a better tree coverage. Soil ameliorations (horticultural soil with fertilizer and horse and pig manure) generally increased the seedling survival rate and improved plant growth. Tree coverage on all the plant trial blocks was mainly established by the three Acacia species. A planting distance of 1 m was recommended for woodland establishment, and such dense seedlings planting would achieve a better tree coverage under a shorter period of time (than the distance of 3 m). Difficulties in woodland establishment were discussed, and the strategies for achieving a better tree growth were recommended. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
316.
Fertilizers applied to turfgrass may pose a threat to surface and groundwater quality, and hence, a study was carried out to evaluate the fate of fertilizer applied to turfgrass of the Clearwater Bay Golf and Country Club in Hong Kong. Lysimeters with reconstituted soils collected from fairways and greens with Bermudagrass (Cynodon dactylon) growing in the surface were used to evaluate the leaching loss of nitrate (NO3 -), ammonium (NH4 +), and phosphate (PO4 3-) for 22 weeks under greenhouse condition. Both soils received a slow release fertilizer at an application rate of 25 (low) or 50 (high) kg N ha-1, and an application frequency of monthly and fortnightly for fairways and greens, respectively, simulating the fertilizer application strategy of the golf course. Both low and high fertilizer application rate supported the same amount of biomass production for each soil type. Breakthrough of NO3 - occurred only in greens after 11 weeks of leaching, but the total amount of NO3 - leached did not differ significantly for the two different fertilizer application rates. The continued addition of fertilizer to greens resulted in a final leachate NO3 - concentration exceeding 45 mg L-1, while fairways maintained a concentration below 5 mg L-1. Also PO4 3- concentration in leachate of greens exceeded the surface water standard of 0.3 mg L-1. The results of the lysimeter study showed that the current application rate on greens would create adverse environmental impacts on the surface water and groundwater due to leaching loss of PO4 3 - and NO3 -.  相似文献   
317.
We assessed the effect of different tillage practices (i.e. conventional tillage and direct drilling) and pasture conditions on the infiltration and distribution of infiltrated rain water in an Australian Alfisol. Bromide was used as a tracer for the infiltrated rain under simulated rainfall conditions. The different infiltration patterns were then related to the macroporosity of the soils.

A 25-year-old permanent pasture was found to have the highest density (number per area) of macropores and percentages of transmitting macropores. A 9-year-old pasture phase in a pasture/crop rotation did not fully restore the macroporosity of the soil. Conventional cultivation by scarifying to 0.1 m for 4 years significantly reduced macropore density as well as continuity when compared with the pasture soil. The reduced macroporosity led to increased run-off by reducing preferential flow and altered the pathway of infiltrated water movement. As a consequence, the increase in water content below 0.1 m in the cultivated soil was predominantly from downward displacement of original soil solution, resulting in more leaching. The infiltrated rain water largely remained on the surface 0.1-m layer. In contrast, macroporosity found under direct drilling was similar to that of the pasture soil.  相似文献   

318.
Mancozeb is a fungicide frequently used in tropical countries. It rapidly decomposes into ethylenethiourea (ETU), a more stable and toxic metabolite than mancozeb that is, therefore, regarded as a pollutant of concern. The objective was to study ETU formation and decay kinetics in soil and water under tropical conditions in order to assess its potential for accumulation. Batch experiments, spiked with either mancozeb or ETU, were carried out under natural (= active) as well as tyndallized conditions. In active soils, dissipation of ETU occurred significantly faster (half‐life 1.5 h) than in tyndallized soils (half‐life time 28 h). In water under natural and sterile conditions, decay was slower than in soils with an ETU half‐life time of 115 and 99 h, respectively. Microbial activity was seen to play an important role in ETU dissipation in soil. However, in water nonbiological processes seem to be more important in the breakdown of the molecule, with hydrolysis being the most probable decay mechanism. Decay of both mancozeb and ETU was found to occur more rapidly than previously reported. The high humidity and temperatures under the simulated humid tropical conditions, and higher microbial activity, lead to more rapid decay of these molecules than under other conditions. Nevertheless, a concentration of 1.29 mg ETU L–1 was still observed 8 d after adding mancozeb (20.83 mg L–1) to water under humid tropical conditions. These results suggest that, in comparable regions in the humid tropics, it is unlikely that ETU would accumulate in soil but it represents a potential risk for accumulation in water bodies.  相似文献   
319.
通过酸解的方法获得不同结晶度的几丁质纳米晶体(Ch N),采用均质协同超声技术制备O/W型皮克林乳液。通过X射线衍射和傅里叶红外光谱计算分析了几丁质纳米颗粒的结晶度及官能团变化,进而对O/W乳液的微观结构、界面接触角、物理稳定性、热稳定性、乳析稳定性、储藏稳定性进行测定,分析了不同结晶度的Ch N对乳液稳定性的影响。结果表明:酸解并不会破坏几丁质的官能团,但是酸解可以改变几丁质的结晶度,且酸解2. 5 h时获得的Ch N结晶度最大,为78. 15%;结晶度高的Ch N制备的乳液形成更稳定的网状结构,Ch N更多地附着在油-水界面,使得乳液具有更小的界面接触角,提高了乳液的亲水性;研究还发现,结晶度高的Ch N制备的乳液热稳定性指数和物理稳定性指数较高,分别为63%和69. 52%;乳析稳定性好,乳析指数不足1%;另外,Ch N稳定的乳液在常温下储藏30 d均不分层,具有良好的储藏稳定性,且结晶度最高的Ch N制备的乳液粒径最小,储藏稳定性最好。因此,可以通过提高几丁质纳米晶体的结晶度制备稳定的O/W型皮克林乳液。  相似文献   
320.
以猪血为原材料,通过硫酸铵盐析和柱层析等方法,分离纯化出2种半胱氨酸蛋白抑制剂激肽原(kininogen).激肽原Ⅰ的得率为0.7%,纯化倍数为613.7;激肽原Ⅱ的得率为24.1%,纯化倍数为295.7.SDS—PAGE结果表明,激肽原Ⅰ和激肽原Ⅱ的分子质量分别为58ku和116ku.激肽原Ⅰ和激肽原Ⅱ对白鲢鱼(Hypophthalmichthys molitrix )鱼浆中肌原纤维蛋白降解都有一定的抑制作用,当激肽原Ⅱ添加量为鱼浆质量的0.03%时,可以使鱼糜凝胶强度提高24%.因此,激肽原可作为添加剂有效提高鱼糜制品的凝胶强度.  相似文献   
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