Effect of SnoN protein on high-glucose-induced expression of fibronectin in primary cultured rat renal tubular cells

AIM: To investigate the effect of Ski-related novel protein N(SnoN) on high-glucose-induced expression of fibronetin (FN) in primary cultured rat renal tubular cells (RTECs). METHODS: The primary renal cells were cultured, and the cell types were indentified to be RTECs. The cells were divided into 3 groups: normal-glucose group (DMEM+2% FBS), high-glucose group (19.5 mmol/L D-glucose+DMEM+2% FBS) and high-osmotic group (19.5 mmol/L D-mannitol+DMEM+2% FBS). The cells were harvested at 30 min, 2 h, 12 h, 24 h, 48 h, 72 h and 96 h. SnoN expression in primary cultured RTECs was knocked down by RNA interference, then the cells were divided into 4 groups: normal-glucose group, high-glucose group, control siRNA group and SnoN siRNA group. The protein expressions of SnoN and FN in RTECs was examined by the methods of Western blotting, immunocytochemistry staining and immunofluorescence cytochemistry. RT-PCR was used to examine the mRNA expression of FN and SnoN. RESULTS: The RTECs constituted the major cell type of cultured cells. SnoN protein was decreased in a time-dependent manner in RTECs under high-glucose condition. The FN protein and mRNA levels raised in high-glucose group and sustained through entire experiment. Moderate reduction of SnoN in RTECs was observed by RNAi strategy, which greatly up-regulated the expression of FN (P<0.05). CONCLUSION: The down-regulation of SnoN participates high-glucose-induced expression of FN in RTECs.     

苏北盐沼环境梯度上甲苯通量变化特征研究

2004年4月至2005年1月在苏北盐沼沿环境梯度采用静态箱技术原位测定了甲苯气体通量。为确定高等植物对通量的贡献,进行了高等植物地上部分去除实验。结果表明:环境梯度上,在生长季(4—10月)盐沼整体上表现为甲苯的净汇,消耗率变化范围为2.50～17.45μmol/(m2.d),其中,互花米草带消耗率最高。在非生长季(11月至次年3月)表层冻结的植被带表现为甲苯的弱源,通量变化范围为5.15～10.76μmol/(m2.d)。光滩全年均表现为排放甲苯。由于盐沼消耗率大于排放率,生长季长于非生长季,所以海岸带盐沼全年表现为消耗甲苯。高等植物地上部分是甲苯的重要汇,但是消耗机制还不清楚。盐沼甲苯净消耗率与土壤温度、光照强度、土壤可溶性盐含量、土壤有机质、硫酸盐含量和大气中甲苯浓度呈正相关关系。     

氮肥运筹对夏玉米产量、氮素利用率及土壤养分残留量的影响

通过2年定位试验,在山西省临汾市采用大田随机区组试验法,在等氮磷钾施肥条件下,研究氮肥运筹对夏玉米产量及其构成因素、不同生育期植株氮磷钾吸收量,并监测0~40 cm土壤速效养分含量动态变化。结果表明,施氮肥处理均使不施氮肥处理(CK)夏玉米显著增产,2014,2015年增产幅度分别为5.72%~27.71%和6.05%~27.84%;其中,一次性施用缓控释肥处理BBF和CRF的夏玉米产量接近或高于常规尿素3次施肥(U3)和2次施肥(U2),增产效果优于一次性基施等量普通复合肥(CF)处理;BBF和CRF处理夏玉米穗粒数、单穗粒重和百粒质量等产量构成因素指标均较优,与U3处理间差异不显著;BBF和CRF处理下植株氮磷钾养分积累量高是产量提高的基础,2年氮肥表观利用率平均达29.59%和28.95%,高于CF处理(22.27%)。常规尿素分次施肥处理施肥次数越多,玉米产量和氮肥利用率越高。各施氮肥处理对土壤速效养分残留量影响在不同生育期各异。BBF和CRF处理0~20 cm土层碱解氮含量随玉米生育期表现为先低后高再低的趋势,这与玉米整个生育期氮素吸收形成一定协同效应,且生育后期残留量低。各施氮肥处理20~40 cm土壤碱解氮含量在苗期变化不大,大喇叭口期和成熟期以U1和U2增加明显。与CK相比,各施氮处理玉米收获后0~40 cm土壤碱解氮残留量均增加。0~20 cm和20~40 cm土壤速效磷和缓效钾含量在生育期的差异较施氮处理间的差异更明显。因此,一次性基施缓控释肥可达到接近或增加常规尿素2次或3次施肥对夏玉米的增产效果,较好地协调养分供应与夏玉米养分吸收,提高氮素养分利用率,后期土壤养分残留量低,实现夏玉米一次性施肥高产高效的效果。     

滴灌施肥与有机配施对金菠萝养分吸收及产量品质影响

本试验以金菠萝(MD-2)为试材,研究了常规施肥和滴灌施肥条件下,有机肥与化肥配施对菠萝生长、养分吸收及产量品质的影响。结果表明：滴灌施肥可显著提高金菠萝总叶片数、茎高、茎粗、D叶长、D叶宽和果柄粗,分别增加了 42.28%、87.81%、49.97%、18.98%、25.56%和54.76%。常规施肥条件下,增施有机肥可显著增加茎高和茎粗,分别增加了56.33%和29.28%。滴灌施肥处理金菠萝根、茎、叶、果柄和果实干重均显著高于常规施肥处理,分别增加了81.77%、303.20%、150.84%、99.56%和86.79%。金菠萝植株N、P、K积累量以及果实横径、单果重和产量均表现为滴灌施肥(含增施有机肥)处理显著高于对照和常规施肥(含增施有机肥)处理。常规施肥处理金菠萝果实的Vc和可滴定酸含量最高,且与其他处理差异显著,但该处理糖酸比最低,增施有机肥显著降低了果实可滴定酸含量。常规施肥+有机肥、滴灌施肥和对照的糖酸比相对较高。     

尿素硝酸铵溶液对玉米产量、品质及养分吸收的影响

采用大田试验,研究了尿素硝酸铵溶液（UAN）在夏玉米上的施用效果。结果显示：与尿素相比,同等施氮条件下,施用UAN可提高玉米产量,主要归因于穗粒数的增加;优化施氮量减量20%施用,玉米产量有所降低,但仍高于尿素优化施氮量处理。同等施氮或减氮20%条件下,施用UAN的产值和经济效益也均高于尿素处理,籽粒粗蛋白和淀粉含量也有提高。玉米籽粒氮、磷含量和累积量,秸秆中磷含量和累积量也显著增加;氮素吸收效率、氮素表观回收率、氮素农学利用效率和氮肥生产效率也高于尿素处理。同等施氮量处理,施用UAN较尿素土壤硝态氮有向地下淋洗的趋势,减量施用,硝态氮向地下淋洗的速率减慢。和尿素相比,施用UAN还可提高玉米籽粒和地上部水分利用效率,减量施用,水分利用效率有所下降。综合而言,从产量、经济效益、氮肥利用效率和水分利用效率来看,施用UAN的效果好于尿素。     

四氧嘧啶与链脲佐菌素诱导小鼠糖尿病模型的效果比较

用相同总剂量的四氧嘧啶1次给药和2次给药及较大剂量链脲佐菌素1次给药3种方法诱导小白鼠糖尿病模型,多次测定血糖,体重等糖尿病相关指标,以确定糖尿病模型建立的最佳方法。结果表明,四氧嘧啶建模率为91．94％,高于链脲佐菌素建模率(66．7％)(P<0．05);四氧嘧啶建模组的死亡率为15％及体重下降率为 18．1％,均高于链脲佐菌素建模组(死亡率3．3％,体重下降率12．0％)(P<0．05);四氧嘧啶连续2次小剂量给药的建模效果优于1次性大剂量给药。两种药物比较,虽然四氧嘧啶的建模率高于链脲佐菌素,但其对建模小鼠的损害亦明显大于链脲佐菌素,建模时连续小剂量给药,并于4．5～5 h后灌胃质量分数50％葡萄糖,可以降低死亡率, 提高建模率。     

High dietary starch impaired growth performance,liver histology and hepatic glucose metabolism of juvenile largemouth bass,Micropterus salmoides

A 60‐day experiment was carried out to investigate dietary starch levels on growth performance, hepatic glucose metabolism and liver histology of largemouth bass, Micropterus salmoides. Fish (initial weight 22.00 ± 0.02 g) were fed five graded levels of dietary corn starch (0, 50, 100, 150 and 200 g/kg). Fish fed low (0 and 50 g/kg) dietary starch showed significantly higher weight gain than other groups (p < .05). Liver lipid and glycogen accumulations were induced when dietary starch higher than 100 g/kg. After 20 days of feeding, hexokinase activity and mRNA expression were decreased in fish fed dietary starch higher than 150 g/kg (p < .05) and the pyruvate kinase showed the opposite tendency. Insulin receptor 1 (irs1), glucagon‐like peptide‐1 receptor and glucose transport protein 2 (glut2) mRNA expression were decreased with the increasing dietary starch after 10 days of feeding (p < .05). These results indicated gluconeogenesis was depressed and β‐oxidation was enhanced in response to high dietary starch, while the glycolysis was inhibited and endocrine system was impaired when fish fed high dietary starch; then, glucose homeostasis was disturbed and finally led to the glucose intolerance of largemouth bass.     

不同浓度的K~+、Ca~(2+)和葡萄糖对乌原鲤精子活力的影响

通过观察精子的快速运动时间和寿命,研究了不同浓度梯度的K+、Ca2+和葡萄糖溶液对乌原鲤精子活力的影响。结果表明:不同浓度的K+、Ca2+和葡萄糖溶液对乌原鲤精子运动的诱导效果不同。3种溶液最适于乌原鲤精子运动的浓度分别为:K+100 mmol/L;Ca2+37.8 mmol/L;葡萄糖125mmol/L,且在这3种溶液低浓度时精子活力较强,超过一定浓度精子的运动开始被抑制。     

Orexin-A stimulates the glucose output of porcine hepatocytes

Orexin-A （OxA） is a key neuropeptide involved in the central control of appetite and the maintenance of energy homeostasis, as well as in the regulation of glycemia. In the present study, OxA receptors, OXtR and OX2R were identified to be highly expressed in porcine hepatocytes. 100 nM OxA could rapidly stimulate the glucose output of porcine hepatocytes in 10min. Primary hepatocytes treated by 1 nM-500 nM OxA for 24 h significantly increase the released glucose and the concentration of albumin, total bile acids and triglyceride in the supernatant. The mRNA expression level of such gluconeogenesis and fat mobilization related genes as acetyl-coA carboxylase, glycogen phosphorylase, fatty acid translocase and phosphoenolpyrurate carboxykinase were also up-regulated accordingly. The results first demonstrated that OxA had direct effect on the hepatic glucose and lipid metabolism, which was an aspect for OxA to exert its maintenance function of energy homeostasis.     

Increasing photosynthetic performance and post-silking N uptake by moderate decreasing leaf source of maize under high planting density

To date,little attention has been paid to the effects of leaf source reduction on photosynthetic matter production,root function and post-silking N uptake characteristics at different planting densities.In a 2-year field experiment,Xianyu 335,a widely released hybrid in China,was planted at 60 000 plants ha~(–1 )(conventional planting density,CD) and 90 000 plants ha~(–1) (high planting density,HD),respectively.Until all the filaments protruded from the ear,at which point the plants were subjected to the removal of 1/2 (T1),1/3 (T2) and 1/4 (T3) each leaf length per plant,no leaf removal served as the control(CK).We evaluated the leaf source reduction on canopy photosynthetic matter production and N accumulation of different planting densities.Under CD,decreasing leaf source markedly decreased photosynthetic rate (P_n),effective quantum yield of photosystem II (ΦPSII) and the maximal efficiency of photosystem II photochemistry (F_v/F_m) at grain filling stage,reduced post-silking dry matter accumulation,harvest index (HI),and the yield.Compared with the CK,the 2-year average yields of T1,T2 and T3 treatments decreased by 35.4,23.8 and 8.3%,respectively.Meanwhile,decreasing leaf source reduced the root bleeding sap intensity,the content of soluble sugar in the bleeding sap,post-silking N uptake,and N accumulation in grain.The grain N accumulation in T1,T2 and T3 decreased by 26.7,16.5 and 12.8% compared with CK,respectively.Under HD,compared to other treatments,excising T3 markedly improved the leaf P_n,ΦPSII and F_v/F_m at late-grain filling stage,increased the post-silking dry matter accumulation,HI and the grain yield.The yield of T3 was 9.2,35.7 and 20.1% higher than that of CK,T1 and T2 on average,respectively.The T3 treatment also increased the root bleeding sap intensity,the content of soluble sugar in the bleeding sap and post-silking N uptake and N accumulation in grain.Compared with CK,T1 and T2 treatments,the grain N accumulation in T3 increased by 13.1,40.9 and 25.2% on average,respectively.In addition,under the same source reduction treatment,the maize yield of HD was significantly higher than that of CD.Therefore,planting density should be increased in maize production for higher grain yield.Under HD,moderate decreasing leaf source improved photosynthetic performance and increased the post-silking dry matter accumulation and HI,and thus the grain yield.In addition,the improvement of photosynthetic performance improved the root function and promoted postsilking N uptake,which led to the increase of N accumulation in grain.