A Screening Test for the Determination of Ethylene Sensitivity

Ethephon, which releases ethylene within plant tissues after application, was chosen to perform assessments of the relative sensitivity of crops to ethylene and to determine which stages of plant development were most sensitive. The species chosen were: barley, wheat, oats, canola and field pea, all of which are important crops in the province of Alberta, Canada. Plants were treated with ethephon at one of 7 different stages. Plants were assessed for their vegetative and reproductive growth, including height, biomass, yield and seed quality. Visual symptoms were photographed and documented to compare them with symptoms caused by ethylene applied as a gas. It was concluded that in barley, wheat and canola the late vegetative and early reproductive stages were most sensitive, at least when sensitivity was defined as reductions in yield and quality. As for field pea, ethephon had no effect on yield but did cause increased numbers of pods, which in certain conditions could lead to increased yields. Significant effects on vegetative growth were only observed in the early vegetative stages of development but with no effects on yield. The screening protocol successfully identified sensitive cultivars and growth stages for further investigation of the effects of ethylene exposure.     

QuEChERS-超高效液相色谱-串联质谱法同时测定斑马鱼中多种激素生物标志物

本文建立了一种同时测定斑马鱼体内23种激素生物标志物的快速分析方法.该方法采用QuEChERS方法对样品进行提取和净化,待测物采用超高效液相色谱-串联质谱法（UPLC-MS/MS）分析,检测的23种激素生物标志物均采用同位素内标法定量.仪器检测限（IDL）范围为0.01-0.19 ng·mL^-1,方法定量限（MQL）范围为0.01-0.12 ng·mL^-1.加标浓度为5 ng·mL^-1和50 ng·mL^-1时,基质效应基本处于67.3%-132.1%之间,相对回收率基本处于73.4%-110.2%之间,方法相对标准偏差介于0.3%-20.0%之间.该方法成功应用于精喹禾灵暴露下斑马鱼体内23种激素生物标志物的含量分析.     

植物激素对平菇菌丝生长及酶活性的影响

采用固体平板和液体摇瓶培养方法,研究了赤霉素、2,4-D、吲哚乙酸和萘乙酸4种激素对平菇-126菌丝生长及酶活性的影响。结果表明,吲哚乙酸虽然能提高发酵液胞外蛋白的含量和过氧化物酶活性,但对菌丝的生长起抑制作用,这与吲哚乙酸能引起平菇菌丝裂解和细胞膜渗漏有关;萘乙酸、低浓度2,4-D能促进菌丝的伸长;萘乙酸、赤霉素在低浓度下也能促进菌丝的分枝,对菌丝的生长整体上起促进作用。除吲哚乙酸外,其他3种激素对平菇菌丝生长影响都有两重性：低浓度下能促进菌丝的生长,浓度过高则会对菌丝生长产生毒害作用。     

Suppression of estrogenic activity of 17-beta-estradiol by beta-cyclodextrin

The suppressive effects of cyclodextrins (CDs) on the strong estrogenic activity of 17β-estradiol (E2) in water environments were investigated in this study. Cyclodextrins are doughnut-shaped molecules that possess a hydrophobic cavity and a hydrophilic exterior. The cavity can incorporate nonpolar molecules as guests to form inclusion complexes. β-CD and 2-hydroxypropyl-β-CD (HP-β-CD) were the most successful in forming a complex with E2 and improving its low aqueous solubility. The E2/CDs complexes bound to the estrogen receptor in a cell-free system as determined by ELISA and suppressed the hormone activities as measured by a yeast two-hybrid assay. These results indicate that hydrophobic E2 is easily transported through the lipid zone of the plasma membrane into the target cell and can bind to the nuclear receptor. However, the hydrophilic E2/β-CD and E2/HP-β-CD complexes do not penetrate the membrane. Therefore, these CDs are able to suppress the hormone activity of E2 through complex formation.     

苦马豆素致糖基转移酶活性改变对小鼠生殖激素分泌的影响

苦马豆素是疯草主要有毒成分,抑制α-甘露糖苷酶的活性,引起N-聚糖加工过程失调。笔者课题组前期研究得出：苦马豆素致糖蛋白激素(促卵泡素和促黄体素)糖基化位点上糖链结构发生改变,引起促性腺激素功能发生改变。而苦马豆素中毒对家畜生殖激素分泌的调节机制尚不明确。苦马豆素腹腔注射对小鼠进行染毒,收集妊娠期和分娩期小鼠的血液、子宫和卵巢组织,检测糖基转移酶活性、生殖激素水平及其受体mRNA和类固醇限速酶蛋白质表达量。结果表明：在妊娠和分娩期,苦马豆素致子宫内膜固有层大量低聚糖蓄积,显著抑制N-聚糖加工过程关键糖基转移酶的活性(P<0.05);染毒组小鼠血液的生殖激素包括促卵泡素(FSH)、促黄体素(LH)、雌激素(E2)和孕酮(P4)水平显著低于对照组(P<0.05)。在整个妊娠周期,染毒组小鼠4种激素受体mRNA的表达量显著低于对照组(P<0.05)。在妊娠后期,染毒组小鼠3-β羟基类固醇脱氢酶(3-βHSD)和芳香化酶(CYP19A1)蛋白表达量显著低于对照组(P<0.05)。苦马豆素可使N-聚糖加工紊乱,引起促性腺激素分泌降低,进一步降低生殖激素受体和性类固醇激素限速酶的表达量,致使性类固醇激素分泌下降,导致生殖激素分泌紊乱,最终结果造成机体繁殖性能下降。     

Bioanalytical and instrumental analysis of thyroid hormone disrupting compounds in water sources along the Yangtze River

Thyroid hormone (TH) agonist and antagonist activities of water sources along the Yangtze River in China were surveyed by a green monkey kidney fibroblast (CV-1) cell-based TH reporter gene assay. Instrumental analysis was conducted to identify the responsible thyroid-active compounds. Instrumentally derived l-3,5,3′-triiodothyronine (T₃) equivalents (T₃-EQs) and thyroid receptor (TR) antagonist activity equivalents referring to dibutyl phthalate (DBP-EQs) were calculated from the concentrations of individual congeners. The reporter gene assay demonstrated that three out of eleven water sources contained TR agonist activity equivalents (TR-EQs), ranging from 286 to 293 ng T₃/L. Anti-thyroid hormone activities were found in all water sources with the TR antagonist activity equivalents referring to DBP (Ant-TR-EQs), ranging from 51.5 to 555.3 μg/L. Comparisons of the equivalents from instrumental and biological assays suggested that high concentrations of DBP and di-2-ethylhexyl phthalate (DEHP) were responsible for the observed TR antagonist activities at some locations along the Yangtze River.