温带混交林碳水通量模拟及其对冠层分层方式的响应--耦合的气孔导度-光合作用-能量平衡模型

利用Leuning建立的耦合的光合作用、气孔导度和能量平衡方程,以将冠层分成多层的方式,包括Gaussian五点积分法、将冠层平均分为多层的方法,逐层计算温带混交林的碳水通量,最后累加至冠层尺度,以模拟CO2和H2O通量。该模型以常规气象观测数据作为驱动变量,计算出冠层与大气之间的碳水交换,与涡动相关系统的通量观测数据进行比较,分析了不同的冠层分层方式对多层模型模拟结果的影响。从3个温带混交林通量站涡动相关系统的能量平衡闭合度来看,中国长白山站CBS、韩国GDK和日本MMF站点的能量平衡比率(EBR)分别为0.76、0.66和1.07,居于国际同类观测范围(0.34—1.2)的中上水平,因此,涡动相关系统的观测数据较为可靠。从碳水通量的日变化来看,用Gaussian五点积分法将冠层分为五层的模型能较好的模拟碳水通量的"单峰形"日变化趋势。夜间Fc为负值且变化趋势较为平缓,表明生态系统进行呼吸作用释放CO2,从日出开始Fc逐渐变为正值,表明生态系统进行光合作用吸收CO2,Fc在中午时分达到最大值,下午Fc逐渐减小,日落之后又回复到夜间的负值。H2O通量的日变化曲线与CO2通量相似,且模拟值与涡动相关实测值具有较好的一致性。在多层模型中,对冠层采用不同的分层方法,对碳水通量模拟结果有一定的影响。以Gaussian五点积分法将冠层分为五层的方法作为对照,分别将冠层平均分为2、5、10、20层的方法得到的碳水通量与其进行比较。从平均值来看,分层越多,H2O通量模拟值越低,而CO2通量模拟值越高。不同的分层方法产生的差异,主要来自于不同层的辐射吸收、温湿度、风速等环境要素的垂直廓线差异,且叶片光合作用对光的响应是非线性的。

Allele Frequency Distribution of the NCAPG c.1326T>G SNP Associated with Growth-Related Traits in Niigata Population of Japanese Black Beef Cattle

Growth performance as well as marbling is the main breeding objectives in Japanese Black cattle, the major beef breed in Japan. A previous study has identified the c.1326T>G single nucleotide polymorphism (SNP) in the NCAPG (non-SMC condensin I complex, subunit G) gene that leads to the amino acid change p.Ile442Met in the NCAPG protein, which is a candidate causative variation for a bovine carcass weight (CWT) quantitative trait locus (QTL). In this study, we first confirmed the association of the c.1326T>G SNP with the growth-related traits, CWT, rib eye area (REA) and rib thickness (RT), and showed significant effect of the SNP genotypes on the marbling trait, beef marbling score (BMS), in the Japanese Black beef cattle population of the Niigata prefecture, with the G allele being associated with a favorable phenotype of these traits. Thus, we concluded that the c.1326T>G SNP is useful for effective marker-assisted selection to increase meat quality and meat productivity in Japanese Black beef cattle of the Niigata prefecture. Furthermore the frequency of the favorable G allele of the c.1326T>G SNP in the Niigata prefecture population was significantly lower than the frequency of this allele in Japanese Black cattle population of the Kagoshima prefecture. However, no statistically significant difference was detected between the allele frequencies estimated by maternal alleles in the half-sib progeny steers in the Niigata prefecture population and obtained in Japanese Black cattle population of the Kagoshima prefecture.

Allele Frequency Distribution in PNLIP Promoter SNP Is Different between High-Marbled and Low-Marbled Japanese Black Beef Cattle

Marbling defined by the amount and distribution of intramuscular fat is regarded as an economically important trait of beef cattle in Japan. The pancreatic lipase gene (PNLIP) is located within the genomic region of a bovine marbling quantitative trait locus. The rat homologue of PNLIP has been previously shown to be regarded as a possible candidate for the gene responsible for intramuscular fat content. These findings suggested that PNLIP was a positional and functional candidate for the marbling gene. In this study, we detected a single nucleotide polymorphism (SNP), g.37288470A > G, at 1917 bp upstream of the PNLIP transcription initiation site between Holstein steers and somatic nuclear-derived cloned steers from a Japanese Black sire with a very high estimated breeding value for marbling by sequencing analysis. Further, we found statistically significant difference in the allelic distribution of the SNP between 17 Japanese Black unrelated sires with extremely high predicted breeding values for marbling and 17 sires with extremely low ones (P = 0.0332). Our findings suggest that g.37288470A > G SNP in the promoter region of PNLIP might be associated with marbling by altering its gene expression, and be useful for effective marker-assisted selection to increase the levels of marbling in Japanese Black beef cattle.

Effects of Two-Year Variation in Soil Moisture Condition on the Development of Larch Root System in Eastern Siberia

Recent climate changes, including an increase in precipitation, have affected tree physiology in eastern Siberia. We investigated the response of larch to wet and dry soil water conditions in pot experiments using larch seedlings grown under near-natural conditions in eastern Siberia over two growing seasons. Three patterns of wet- and dry-treatment combinations were applied over 2 years: wet treatments in 2006 and 2007 (WW treatment), dry in 2006 and wet in 2007 (DW treatment), and dry in 2006 and 2007 (DD treatment). After 1 year of treatment, no significant difference between the dry and wet treatment was found in root distribution and needle water content, except for the content of abscisic acid in roots. After 2 years of treatment, the DW treatment induced different tendencies in the gas exchange activity and in the needle biomass and root distribution of seedlings in comparison with WW treatments, despite the same water condition in 2007. We suggest a possibility that seedlings that experience drought stress might store some memory of drought that influences their physiology in the next growing season.

Diabetic mouse models

The number of patients with lifestyle-related diseases, such as cardiovascular disease, diabetes mellitus, hypertension, atherosclerosis, and cancer, is increasing all over the world, and that of diabetics is increasing especially rapidly. Diabetic animal models have played a key role in elucidating the etiology of diabetes and developing anti-diabetic drugs. In this review, we overviewed characteristics of diabetic mouse models and pharmacological evaluation using the diabetic models.

Effect of phlorizin on metabolic abnormalities in Spontaneously Diabetic Torii (SDT) rats

The Spontaneously Diabetic Torii (SDT) rat is a novel model for nonobese type 2 diabetes. In this study we investigated the glycolipid metabolic changes with phlorizin-treatment, which inhibits intestinal glucose uptake and renal glucose reabsorption, in male SDT rats. Phlorizin (100 mg/kg, b.i.d., s.c.) was administered for 4 weeks to SDT rats from 20 to 24 weeks of age. As a result, phlorizin reduced the development of hyperglycemia and decreased the hemoglobin A1c (HbA1c) levels. In the liver, phlorizin increased mRNA levels of glucokinase, the enzymes related with the glycogen cascade and the proteins associated with lipid metabolism. In conclusion, chronic administration of phlorizin in SDT rats produced a good glycemic control and an improvement in liver function.

Female spontaneously diabetic Torii fatty rats develop nonalcoholic steatohepatitis-like hepatic lesions

AIM:To investigate the histological features of the liver in spontaneously diabetic Torii(SDT) fatty rats compared with age-matched Sprague-Dawley(SD) rats.METHODS:Female SDT Leprfa(SDT fatty) rats and age-matched SD rats were fed ad libitum. Body weight and biochemical parameters,such as serum glucose,triglyceride(TG),total cholesterol(TC),alanine aminotransferase(ALT) and aspartate aminotransferase(AST) levels as well as fatty acid and TG accumulation in the liver were evaluated at 8 wk of age in the nonfasting state and at 8-wk intervals from 8 to 40 wk of age. Histopathological examinations of the liver were performed using hematoxylin and eosin and Sirius Red staining as well as double staining for ED-1 and toluidine blue. The expression of genes involved in TG synthesis,inflammation,and fibrosis was examined in the liver.RESULTS:SDT fatty rats showed significantly increased body weight compared with SD rats. Serum glucose,TG,and TC levels were significantly higher in SDT fatty rats compared with SD rats. The serum AST and ALT levels in SDT fatty rats were significantly elevated at 8 wk of age compared with the levels in SD rats. Hepatic TG content was marked in SDT fatty rats from 8 to 32 wk of age. Histopathologically,severe hepatosteatosis accompanied by inflammation was observed at 8 wk of age,and fibrosis started to occur at 32 wk of age. Furthermore,Sirius Red and ED-1 staining were increased in the liver at 32 wk of age. Hepatic gene expression related to TG synthesis,inflammation and fibrosis tended to increase in SDT fatty rats compared with SD rats,and the gene expression related to TG secretion was decreased in SDT fatty rats compared with SD rats. CONCLUSION:Female SDT fatty rats have the potential to become an important animal model of nonalcoholic steatohepatitis with type 2 diabetes and obesity.

No replicated association of the c.-312A >G in<i>EDG</i>1 with marbling in Niigata population of Japanese Black beef cattle

Marbling, defined by the amount and the distribution of intramuscular fat and measured as beef marbling score (BMS), is an economically important trait of beef cattle in Japan. We recently reported that a single nucleotide polymorphism (SNP), namely, c.-312A > G, in the endothelial differentiation sphingolipid G-proteincoupled receptor, 1 (EDG1) gene was associated with the BMS level in the Japanese Black beef cattle population of Oita prefecture, with the G allele being associated with a high level of the BMS. Thus, the c.-312A > G SNP seems to be a candidate marker for marker-assisted selection. In this study, we investigated whether this association could be replicated in the Japanese Black beef cattle population of Niigata prefecture and analyzed the effect of the SNP genotypes on the carcass traits other than the BMS. No significant differences in the BMS level were detected among the genotypes of the c.-312A > G SNP in the Niigata Japanese Black beef cattle population. The SNP genotype had no significant effects on the carcass weight, rib eye area and rib thickness of the cattle population. These findings suggested that the association of the c.-312A > G SNP with the BMS level in the Japanese Black beef cattle population was not replicated in the Niigata population, and revealed no effects of the SNP genotype on the beef productivity in the Niigata population. Thus, we concluded that the c.-312A > G SNP is not useful for effective marker-assisted selection to increase meat quality and, additionally, meat productivity in Japanese Black beef cattle of Niigata prefecture.

Replicated association of the single nucleotide polymorphism in PNLIP with marbling in Niigata population of Japanese Black beef cattle

Marbling is regarded as an economically important trait of beef cattle inJapan, and measured as a beef marbling score (BMS). Our previous study reported an association between a single nucleotide polymorphism (SNP), rs4164 8172, in the pancreatic lipase (PNLIP) gene and the BMS level, using the Japanese Black beef cattle population of Oita prefecture. Further, we showed that the T allele at the rs41648172 SNP is associated with a high level of the BMS. Thus, we suggested that the rs41648172 SNP seems to be a candidate marker for marker-assisted selection. Our present study was designed to investigate whether this association could be replicated in other independent Japanese Black cattle population and analyze the effect of the SNP genotypes on the carcass traits other than the BMS. We detected the marginally significant effect of the genotypes of the rs41648172 SNP on the BMS level by using the Japanese Black beef cattle population of Niigata prefecture (P = 0.0919), and obtained the result of the T allele associated with an increase in the BMS level, consistent with our previous data. In addition, we showed no significant association of the SNP with the subcutaneous fat thickness, carcass weight, rib eye area, rib thickness and yield estimate in the Japanese Black beef cattle population ofNiigataprefecture. Thus, we concluded that the rs41648172 SNP was useful for effective marker-assisted selection to increase the BMS level in Japanese Black beef cattle, based on the replicated association of the rs41648172 SNP with the BMS level in the other independent Japanese Black beef cattle population and no effect of the SNP genotypes on the carcass traits other than BMS.

Non-Obese Type 2 Diabetic Rat Models-GK Rat and SDT Rat

The number of diabetic patients has recently been increasing all over the world together with lifestyle changes including sedentary life and high-calorie diet intake, and as a result the increase in these suffering from diabetes mellitus has become a global issue. Diabetic animal models play a key role in bettering our understanding of the pathophysiology of diabetes and in developing new therapies for the disease. Diabetes is classified into two types, type 1 and type 2, and type 2 diabetes is chiefly caused by a depletion of insulin secretion in the pancreas and insulin resistance in peripheral tissues. The Goto-Kakizaki (GK) rat and the Spontaneously Diabetic Torii (SDT) rat are genetic non-obese type 2 diabetic models, and the both rats are considered to be suitable models for investigating the etiology of the depletion of insulin secretion and impaired glucose tolerance. In this review, we overviewed the outline of pathophysiological features in GK rats and SDT rats, including biological parameters and pharmacological responses.

Elevated glucagon-like peptide-1 on a high-fat diet feeding prevents the incidence of diabetes mellitus in Spontaneously Diabetic Torii <i>Lepr^fa</i>rats

Nutritional regulation plays a critical role to reduce the incidence or progression of diabetes mellitus. In this study, we investigated the effects of a high-fat diet on Spontaneously Diabetic Torii Leprfa (SDT fatty) rats, a novel model for obese type 2 diabetes. The SDT fatty rats were divided into two dietary groups, which were fed a high-fat diet or a standard diet for 18 weeks, from 6 to 24 weeks of age. The calorie intake in the high-fat diet (HF) group was reduced after 10 weeks of age and the group inhibited an incidence of diabetes. Interestingly, the HF induced an increase of serum glucagon-like peptide-1 (GLP-1) levels in SDT fatty rats with refeeding. Fat tissue weights in the HF group increased, but the visceral fat/subcutaneous fat (V/S) ratio decreased. Moreover, histopathological observations revealed an improvement of the pancreatic abnormalities and fatty liver in the HF group. In conclusion, a preventive effect on diabetes in rats fed a high-fat diet has a relation with an increase in incretin hormone, and it might be advantageous for prevention of incidence or progression of diabetes to develop functional foods inducing an increase in incretin hormone.

PnET-CN模型对东亚森林生态系统碳通量模拟的适用性和不确定性分析

东亚地区森林类型多样,开展区域生态系统碳循环模拟时应考虑森林类型的差异。论文利用基于叶氮浓度-最大净光合作用速率关系的PnET-CN模型,对东亚地区8个森林生态系统通量观测站点的总生态系统碳交换(GEE)和生态系统呼吸(RE)进行模拟,以探讨模型的适用性并对不确定性来源进行分析。研究结果表明:1PnET-CN模型能较为准确地模拟东亚地区大部分森林生态系统站点的GEE和RE;2模型的适用性排序依次为温带、寒温带、亚热带、热带,模型未能很好地模拟热带湿地森林GEE和RE的季节与年际变异;3在同一气候区中,PnET-CN模型更加适用于针叶林碳交换的模拟;4PnET-CN模型比较准确地反映了东亚森林生态系统GEE、RE对气候因子(例如,温度或辐射)的响应,但在低温、较弱辐射条件下模型低估了GEE,在高温或较强辐射条件下高估了GEE;在低温条件下模型低估了RE,在高温条件下模型高估了RE。针对东亚多个森林通量站点的模拟情况,论文提出模型应在以下方面进行改进:1PnET-CN模型计算物候时除了考虑温度之外还应加入土壤湿度的影响,并对不同气候区森林生态系统赋予不同叶片凋落时长;2PnET-CN模型中温度对GEE的限制以及光合最适温度应该根据不同站点设置;3PnET-CN模型应该考虑森林生态系统对环境胁迫的适应性,加强对干旱等干扰的模拟;4同时对于拥有复杂水文条件的森林生态系统应该改进土壤含水量的算法,以准确反映该类型森林生态系统GEE和RE的季节变化。

The influence of meteorology and phenology on net ecosystem exchange in an eastern Siberian boreal larch forest

Aims Boreal forests play an important role in the global carbon cycle.Compared with the boreal forests in North America and Europe,relatively few research studies have been conducted in Siberian boreal forests.Knowledge related to the role of Siberian forests in the global carbon balance is thus essential for a full understanding of global carbon cycle.Methods This study investigated the net ecosystem exchange(NEE)during growing season(May-September)in an eastern Siberian boreal larch forest for a 3-year period in 2004-2006 with contrasting meteorological conditions.Important FindingsThe study found that the forest served as a carbon sink during all of the 3 studied years;in addition,the meteorological conditions essentially influenced the specific annual value of the strength of the carbon sinks in each year.Although 2005 was the warmest year and much wetter than 2004,2005 also featured the greatest amount of ecosystem respiration,which resulted in a minimum value of NEE.The study also found that the phenological changes observed during the three study years had a relatively small effect on annual NEE.Leaf expansion was 26 days earlier in 2005 than in the other 2 years,which resulted in a longer growing season in 2005.However,the NEE in 2005 was counterbalanced by the large rate of ecosystem respiration that was caused by the higher temperatures in the year.This study showed that meteorological variables had larger influences on the interannual variations in NEE for a Siberian boreal larch forest,as compared with phenological changes.The overall results of this study will improve our understanding of the carbon balance of Siberian boreal larch forests and thus can help to forecast the response of these forests to future climate change.