3-Hydroxy-3-methylglutaryl coenzyme A （HMG CoA） reductase produces mevalonate, an important intermediate in the synthesis of cholesterol and essential nonsterol isoprenoids. The reductase is subject to an exorbitant...3-Hydroxy-3-methylglutaryl coenzyme A （HMG CoA） reductase produces mevalonate, an important intermediate in the synthesis of cholesterol and essential nonsterol isoprenoids. The reductase is subject to an exorbitant amount of feedback control through multiple mechanisms that are mediated by sterol and nonsterol end-products of mevalonate metabolism. Here, I will discuss recent advances that shed light on one mechanism for control of reductase, which involves rapid degradation of the enzyme. Accumulation of certain sterols triggers binding of reductase to endoplasmic reticulum （ER） membrane proteins called Insig-1 and Insig-2. Reductase-Insig binding results in recruitment of a membrane-associated ubiquitin ligase called gp78, which initiates ubiquitination of reductase. This ubiquitination is an obligatory reaction for recognition and degradation of reductase from ER membranes by cytosolic 26S proteasomes. Thus, sterol-accelerated degradation of reductase represents an example of how a general cellular process （ER-associated degradation） is used to control an important metabolic pathway （cholesterol synthesis）.展开更多
Through linear regression analysis to the trend of annual,seasonal and monthly precipitation of 72 meteorological stations in Hubei Province from 1961 to 1995,it is revealed that: 1) annual precipitation was increasin...Through linear regression analysis to the trend of annual,seasonal and monthly precipitation of 72 meteorological stations in Hubei Province from 1961 to 1995,it is revealed that: 1) annual precipitation was increasing by 61.0mm/10a in the eastern part of Hubei (112°E as a dividing line) and decreasing by 34.9mm/10a in the western part; 2) precipitation in winter and summer (January,February,March,June and July) was increasing in almost whole province which usually with non-uniformity of precipitation distribution from the south to the north. The precipitation in spring,autumn and winter (April,September,November and December) was decreasing in most of the areas which usually with non-uniformity of precipitation distribution from the east to the west. March and December were transition periods between two spatial distribution patterns mentioned above; 3) the eastern part of Hubei has beome one of precipitation increasing centers in China. The results was consistent with the trend that more frequent flood and drought events happened in Hubei Province which are more different in spatial and temporal scales.展开更多
Basic climatic characteristics are analyzed concerning the precipitation anomalies in raining seasons over regions south of the Changjiang River (the Yangtze). It finds that the regions are the earliest in eastern Chi...Basic climatic characteristics are analyzed concerning the precipitation anomalies in raining seasons over regions south of the Changjiang River (the Yangtze). It finds that the regions are the earliest in eastern China where raining seasons begin and end. Precipitation there tends to decrease over the past 50 years. Waters bounded by 9(S -1(S, 121(E - 129(E are the key zones of SST anomalies that affect the precipitation in these regions over May ~ July in preceding years. Long-term air-sea interactions make it possible for preceding SST anomalies to affect the general circulation that come afterwards, causing precipitation anomalies in the raining seasons in regions south of the Changjiang River in subsequent years.展开更多
The data of 16o national meteorological observatory （NMO） stations with long-term monthly temperature data for China were analyzed in this study to show the basin-centered summer temperature decrease against global ...The data of 16o national meteorological observatory （NMO） stations with long-term monthly temperature data for China were analyzed in this study to show the basin-centered summer temperature decrease against global warming in the past half century. The summer and winter isotherm structures of 1950s and 1990s worked out by interpolation show the isotherm structure variations： the isotherm structure generally moves northward in winter, but in summer it is characterized with separate high-temperature and low-temperature centers and the isotherm structure moves inward the centers with global warming, indicating that the temperature in the highland areas increases but that in the lowland areas decreases in the summer of the duration. The possible mechanism of the basin-centered temperature decrease in summer is discussed in this paper.展开更多
Seasonal rainfall predictability over the Huaihe River basin is evaluated in this paper on the basis of 23-year(1981-2003) retrospective forecasts by 10 climate models from the Asia-Pacific Economic Cooperation(APEC) ...Seasonal rainfall predictability over the Huaihe River basin is evaluated in this paper on the basis of 23-year(1981-2003) retrospective forecasts by 10 climate models from the Asia-Pacific Economic Cooperation(APEC) Climate Center(APCC) multi-model ensemble(MME) prediction system.It is found that the summer rainfall variance in this basin is largely internal,which leads to lower rainfall predictability for most individual climate models.By dividing the 10 models into three categories according to their sea surface temperature(SST) boundary conditions including observed,predicted,and persistent SSTs,the MME deterministic predictive skill of summer rainfall over Huaihe River basin is investigated.It is shown that the MME is effective for increasing the current seasonal forecast skill.Further analysis shows that the MME averaged over predicted SST models has the highest rainfall prediction skill,which is closely related to model's capability in reproducing the observed dominant modes of the summer rainfall anomalies in Huaihe River basin.This result can be further ascribed to the fact that the predicted SST MME is the most effective model ensemble for capturing the relationship between the summer rainfall anomalies over Huaihe River basin and the SST anomalies(SSTAs) in equatorial oceans.展开更多
文摘3-Hydroxy-3-methylglutaryl coenzyme A （HMG CoA） reductase produces mevalonate, an important intermediate in the synthesis of cholesterol and essential nonsterol isoprenoids. The reductase is subject to an exorbitant amount of feedback control through multiple mechanisms that are mediated by sterol and nonsterol end-products of mevalonate metabolism. Here, I will discuss recent advances that shed light on one mechanism for control of reductase, which involves rapid degradation of the enzyme. Accumulation of certain sterols triggers binding of reductase to endoplasmic reticulum （ER） membrane proteins called Insig-1 and Insig-2. Reductase-Insig binding results in recruitment of a membrane-associated ubiquitin ligase called gp78, which initiates ubiquitination of reductase. This ubiquitination is an obligatory reaction for recognition and degradation of reductase from ER membranes by cytosolic 26S proteasomes. Thus, sterol-accelerated degradation of reductase represents an example of how a general cellular process （ER-associated degradation） is used to control an important metabolic pathway （cholesterol synthesis）.
文摘Through linear regression analysis to the trend of annual,seasonal and monthly precipitation of 72 meteorological stations in Hubei Province from 1961 to 1995,it is revealed that: 1) annual precipitation was increasing by 61.0mm/10a in the eastern part of Hubei (112°E as a dividing line) and decreasing by 34.9mm/10a in the western part; 2) precipitation in winter and summer (January,February,March,June and July) was increasing in almost whole province which usually with non-uniformity of precipitation distribution from the south to the north. The precipitation in spring,autumn and winter (April,September,November and December) was decreasing in most of the areas which usually with non-uniformity of precipitation distribution from the east to the west. March and December were transition periods between two spatial distribution patterns mentioned above; 3) the eastern part of Hubei has beome one of precipitation increasing centers in China. The results was consistent with the trend that more frequent flood and drought events happened in Hubei Province which are more different in spatial and temporal scales.
基金Interannual and Interdecadal Variation Laws Governing the Mei-yu in the Changjiang-Huanhe Rivers valley Key Foundation Project in National Natural Science Foundation (40233037) Research on the Interactions between the South Asia High and Asia Monsoon a
文摘Basic climatic characteristics are analyzed concerning the precipitation anomalies in raining seasons over regions south of the Changjiang River (the Yangtze). It finds that the regions are the earliest in eastern China where raining seasons begin and end. Precipitation there tends to decrease over the past 50 years. Waters bounded by 9(S -1(S, 121(E - 129(E are the key zones of SST anomalies that affect the precipitation in these regions over May ~ July in preceding years. Long-term air-sea interactions make it possible for preceding SST anomalies to affect the general circulation that come afterwards, causing precipitation anomalies in the raining seasons in regions south of the Changjiang River in subsequent years.
基金The work is supported by NKBRSF, PR China, No. 2oo2CBII1507 The National Key of Science and Technology, No. 2oo4BAso8B22 the Chinese National Natural Science Foundation （90302006, 90511026）；the Hundred Talents Program （2004401, KZCX3-SW-339） of the Chinese Academy of Sciences and the Project for 0utstanding Scientists （40121101） of the National Natural Science Foundation of China.
文摘The data of 16o national meteorological observatory （NMO） stations with long-term monthly temperature data for China were analyzed in this study to show the basin-centered summer temperature decrease against global warming in the past half century. The summer and winter isotherm structures of 1950s and 1990s worked out by interpolation show the isotherm structure variations： the isotherm structure generally moves northward in winter, but in summer it is characterized with separate high-temperature and low-temperature centers and the isotherm structure moves inward the centers with global warming, indicating that the temperature in the highland areas increases but that in the lowland areas decreases in the summer of the duration. The possible mechanism of the basin-centered temperature decrease in summer is discussed in this paper.
基金supported by the National Natural Science Foundation of China (41175073)the National Science Foundation of China (NSFC)-Yunnan Province Joint Grant (U1133603)+1 种基金the National Basic Research Program of China (2010CB428403 and 2009CB421406)the NOAA Climate Program Office and Michigan State University (NA10OAR4310246 and NA12OAR 4310081)
文摘Seasonal rainfall predictability over the Huaihe River basin is evaluated in this paper on the basis of 23-year(1981-2003) retrospective forecasts by 10 climate models from the Asia-Pacific Economic Cooperation(APEC) Climate Center(APCC) multi-model ensemble(MME) prediction system.It is found that the summer rainfall variance in this basin is largely internal,which leads to lower rainfall predictability for most individual climate models.By dividing the 10 models into three categories according to their sea surface temperature(SST) boundary conditions including observed,predicted,and persistent SSTs,the MME deterministic predictive skill of summer rainfall over Huaihe River basin is investigated.It is shown that the MME is effective for increasing the current seasonal forecast skill.Further analysis shows that the MME averaged over predicted SST models has the highest rainfall prediction skill,which is closely related to model's capability in reproducing the observed dominant modes of the summer rainfall anomalies in Huaihe River basin.This result can be further ascribed to the fact that the predicted SST MME is the most effective model ensemble for capturing the relationship between the summer rainfall anomalies over Huaihe River basin and the SST anomalies(SSTAs) in equatorial oceans.
