In vitro suppression of quercetin on hypertrophy and extracellular matrix accumulation in rat glomerular mesangial cells cultured by high glucose

Quercetin's protective effects on the glomerulosclerosis of diabetic nephropathy (DN) in rat mesangial cells were investigated. The cell cycles, type IV collagen and laminin, TGF-β₁ mRNA, Smad 2/3 and Smad 7, and activities of cell antioxidases were measured. Compared with the high glucose group, quercetin may decrease the cell percentages of G₀/G₁ phase, Smad 2/3 expression, laminin and type IV collagen, and TGF-β₁ mRNA level significantly. The antioxidant capacity, the cell percentages of S phase and Smad 7 expression was significantly increased by quercetin. These results suggest that quercetin is a protective agent against glomerulosclerosis in DN.     

Distribution and plant community associations of the understory bamboo <Emphasis Type="Italic">Fargesia qinlingensis</Emphasis> in the Foping National Nature Reserve,China

• Introduction  

Fargesia qinlingensis is the primary food source for the endangered giant panda during the summer months in the Qinling Mountains, but little is known about its spatial distribution and plant community associations.     

Effect of Rice Residues on Carbon Dioxide and Nitrous Oxide Emissions from a Paddy Soil of Subtropical China

A pot incubation experiment with rice residues (straw and root) was conducted under aerobic condition (60% of WHC, water holding capacity) for a period of 55 days in a greenhouse. The emissions of carbon dioxide (CO₂) and nitrous oxide (N₂O) were determined by the closed chamber method in a paddy soil. The soil was derived from quaternary red clay, and collected from the Ecological Station of Red Soil, the Chinese Academy of Sciences, located in Jiangxi Province, a subtropical region of China. The emissions of CO₂ and N₂O were increased by the amendment of rice residues. Significantly positive correlation was found between N₂O and CO₂ fluxes (R = 0.650*?0.870*, P ≤ 0.05). The cumulative emissions during the early stage of the incubation (<25 days after residue addition) accounted for about 67%–86% and 67%–80% of the total amount of CO₂ and N₂O emissions, respectively. Cumulative emissions and emission factors of the two gases were higher in the soils amended with rice straw than those with rice root. The two gas fluxes were positively correlated with microbial biomass C and N, as well as soluble organic C. N₂O flux was positively correlated with NH₄ ⁺–N content at the early stage (<25 days), and negatively with NO₃ ^?–N content at the later stage of this incubation (25–55 days), implying that both nitrification and denitrification may have contributed to N₂O production.     

Evaluation of isoflavone aglycon and glycoside distribution in soy plants and soybeans by fast column high-performance liquid chromatography coupled with a diode-array detector

An ultrafast HPLC/UV-vis DAD method working at 254 nm was applied for the determination of isoflavone aglycons and glycosides (genistin, genistein, daidzein, daidzin, glycitin, glycitein, ononin, formononetin, sissotrin, and biochanin A) in roots, stems, leaves, and soy pods of soy plants and in soybeans of five varieties (Korada, Quito, Rita, OAC Erin, and OAC Vison). An Atlantis dC18 ultrafast RP chromatographic column (20 mm x 2.1 mm, 3 microm particle size) was applied for separation of the isoflavone aglycons and glycosides. A flow rate of the mobile phase (0.1% (v/v) acetic acid, pH 3.75-solvent A and methanol-solvent B) was 0.35 mL min(-1), and the column temperature was 36 degrees C. A linear gradient profile from 13 up to 22% B (v/v) from zero to 2.5 min, up to 30% B to 3.21 min, up to 35% B to 4 min, up to 40% B to 4.5 min, up to 50% B to 5.14 min, and followed by negative gradient up to 13% B to 7.71 min was used. The absolute limits of detection per sample injection (5 microL) were the highest for biochanin A (166.2 fmol) and the lowest for genistin (17.0 fmol), respectively. An accelerated solvent extraction (ASE) in combination with sonication was applied for isolation of biologically active compounds. A solid-phase extraction procedure was used to purify the extracts in the case of analysis of soy plants parts. The recoveries of 96-106% were obtained for the different concentrations of the isoflavone aglycons and glycosides and the different matrixes (overall RSDs 2-9%). The highest isoflavone concentrations were found in roots (12.5 microg g(-1) dry weight), while the amounts were about 3-1100 microg g(-1) fresh weight in different varieties of soybeans.     

黄土高原粮食供求前景分析

根据多年的研究积因，在分析黄土高原土地资源与质量的基础上，对粮食生产的现状与力，以及粮食生产人口增长趋势等几方面问题进行了论述。到２０００和２０１０年人均可保有粮口０．１７ｈｍ＾２和０．１５ｈｍ＾２，粮食生产力至少可分别达到２５２０ｋｇ／ｈｍ＾２和３４７０ｋｇ／ｈｍ＾２，人口自然增长率可控制到《中国计划生育纲要》规定的目标，人均粮在两个时段将分别达到４００ｋｇ和５００ｋｇ以上。     

土壤颗粒尺寸分布分维及对粘附行为的影响

依据Tyler和Wheatcraft推导的土壤颗粒累积质量—尺寸标度关系,计算了我国主要土壤的颗粒尺寸分布(PSD)分维,结果表明:淡栗钙土、黄绵土、黑垆土、褐土((土娄)土)、潮土、灰漠土、黑土、黄棕壤、黄壤、红壤及赤红壤(砖红壤)的PSD分维依次增大,土壤粘粒含量增加使其PSD分维增大。结合上壤颗粒表面分形特性及土壤粘附的基本原理,探讨了土壤PSD分维对土壤—固体表面粘附行为的影响。PSD分维高的土壤与固体表面粘附力大,与固体表面发生明显粘附的起始含水量提高,发生明显粘附的含水量区间增宽。     

甜高粱田间去叶装置的初步试验

研制的甜高粱田间去叶装置,可安装在收割机前,利用拖拉机液压升降系统压力油为动力,通过液压马达驱动橡胶弹性剥指高速回转,剥去甜高粱叶。试验表明,采用这种弹性剥指去叶装置,可在茎秆切断前,于机械化收割同时在田间去叶,去叶率较高。液压传动型式简化了结构,解决了总体布置的难度,有利于在生产中应用。     

科学运用机械通风推进绿色安全储粮

通过科学合理运用机械通风技术,同时辅以隔热保冷密闭措施,可使储粮较长时间处于低温或准低温状态,不仅能有效抑制害虫及微生物的生长繁殖和危害,减少或避免化学药剂的熏蒸;还能有效预防和消除储粮的发热霉变,延缓粮食的品质劣变,确保粮情稳定,达到保质保鲜,实现绿色安全储粮。     

微波消解——凯式定氮法在大豆蛋白质含量测定中的应用

介绍微波消解-凯式定氮法测定大豆中蛋白质含量的方法,采用密闭微波消解样品,优化微波消解条件。方法的相对标准偏差为1.75%,回收率在99.2%~102.2%之间。分析结构与国标对照无显著性差异。该法具有消化时间短、环境污染小等特点,为快速测定大豆蛋白含量以及改善操作人员工作环境,提供了参考。     

氟磺胺草醚降解菌的分离鉴定及生长特性研究

氟磺胺草醚广泛应用于大豆田防除阔叶杂草,其长残留问题十分严重,微生物降解是解决氟磺胺草醚残留问题的有效途径。利用高压富集的方法,从长期施用氟磺胺草醚的田间土壤中,分离筛选出6株能够以氟磺胺草醚为唯一碳源生长的降解菌,其中一个菌株在查氏液体培养基中培养5d,对40mg a.i./L氟磺胺草醚的降解率为92.13%。通过形态特征鉴定并对该菌株18S rRNA的部分序列进行基因测序,对其在系统发育分类学上的地位加以分析,同时研究环境条件对其生长的影响。结果表明,该菌株为真菌,初步鉴定为黄曲霉(Aspergillus flavus),实验室命名为TZ1985。菌株TZ1985最适生长温度为25℃,最适培养基pH值为7.0,生长最适葡萄糖含量为0.6%,生长最适氟磺胺草醚的浓度是10mg a.i./L。