Fluazifop-butyl causes membrane peroxidation in the herbicide-susceptible broad leaf weed bristly starbur (Acanthospermum hispidum)

In order to clarify the action mechanism of fluazifop-butyl, an aryloxyphenoxypropionate (AOPP) herbicide in bristly starbur (Acanthospermum hispidum DC.), a unique fluazifop-butyl-susceptible broad-leaved weed, ethylene evolution and membrane lipid peroxidation in the plant seedlings were investigated. Foliar application of fluazifop-P-butyl induced ethylene evolution only from bristly starbur, but not from oat (Avena sativa L.), another fluazifop-butyl-susceptible species, and two tolerant species, pea (Pisum sativum L.) and hairy beggarticks (Bidens pilosa L.). The other AOPP herbicides, quizalofop-ethyl and fenoxaprop-ethyl, and a cyclohexanedione (CHD) herbicide, sethoxydim, did not enhance ethylene production from bristly starbur. This fluazifop-butyl-induced ethylene production in bristly starbur was completely suppressed by aminoethoxyvinylglycine (AVG), a 1-aminocyclopropane-1-carboxylic acid (ACC) synthase inhibitor, but not by p-chlorophenoxyisobutyric acid (PCIB), an anti-auxin compound, suggesting this evolved ethylene was not auxin-induced. Phytotoxic action by fluazifop-P-butyl (5 μM) in bristly starbur was reduced markedly by two lipid-soluble antioxidants, vitamin E, and ethoxyquin. The ethylene production from the plant was also inhibited by these two antioxidants. Content of malondialdehyde, an indicator of lipid peroxidation, increased only by fluazifop-P-butyl in bristly starbur seedlings but not in oat, and this increase was inhibited by ethoxyquin. These results strongly suggest that the primary site of action for fluazifop-butyl in bristly starbur is on the membranes and active oxygen species and/or free radicals are involved in peroxidation. Ethylene evolution is probably induced by these reactive oxygen species.     

盐胁迫对珠美海棠和山定子膜保护酶系统的影响

实验以耐盐种珠美海棠(MaluszumiMats)和盐敏感种山定子[Malusbaccata(L.)Borkh]为试材,比较研究了在盐胁迫下叶片质膜透性、叶绿素和丙二醛(MDA)含量、膜保护酶超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)活性及根质膜透性的变化,为探索苹果属植物耐盐机制提供素材。结果表明,盐胁迫对根质膜透性没有明显的影响;但导致叶片质膜透性增加,盐敏感种山定子的质膜透性高于耐盐的珠美海棠。随盐胁迫加重,叶绿素a、b含量降低,叶绿素a/b比值增加,类胡萝卜素变化不明显。MDA含量随盐胁迫而升高,但珠美海棠低于山定子。山定子叶片中SOD、POD、CAT活性随盐胁迫加重而降低,而珠美海棠SOD活性在盐胁迫下保持稳定,POD、CAT活性增高。由此可见珠美海棠在盐胁迫条件下有活性较高的膜保护酶系统。     

Ghrelin对大鼠胃蛋白酶和H+-K+-ATP酶活性的体外作用

从断奶大鼠中获得新鲜的胃粘膜,分离培养胃粘膜上皮细胞,培养30 h后,试验组换为分别含有1×10^-4、1×10^-3、1×10^-2和1×10^-1μmol/L生长素（Ghrelin）的新鲜培养液,对照组换为不含Ghrelin的正常新鲜培养液。继续培养4 h,收集培养液和细胞,分别测定培养液中胃蛋白酶活性和细胞中H^＋-K^＋-ATPase活性。试验结果表明：1×10^-3μmol/L的Ghrelin可显著提高胃蛋白酶的活性（P〈0.05）,1×10^-4、1×10^-3和1×10^-2μmol/L的Ghrelin显著提高胃黏膜上皮细胞中H^＋-K^＋-ATPase的活性（P〈0.05）。表明Ghrelin体外作用于胃粘膜上皮细胞可刺激胃蛋白酶和胃酸的分泌。     

杨树膜脂脂肪酸和磷脂的组成与抗寒性的关系

对一年生草本植物小麦、水稻、玉米等从生物膜膜脂的组成和配比的角度来探讨抗寒机理已有很多的报告,对多年生木本植物的研究还不很多。以前的研究结果大部分都支持了脂肪酸不饱和度与抗寒性的相关性,但各种植物也不尽相同,甚至有一些相反的结论。为了比较杨树耐寒品种和不耐寒品种在化学和生理特性上的差别,本研究用现代仪器分析方法测定了耐寒欧美杨(45杨)和不耐寒美洲黑杨(69杨)的膜脂总脂肪酸、磷脂组分的配比和总磷脂含量,为判别杨树无性系新品种的抗寒能力提供了依据。     

耐受自身代谢产物及耐二甲基亚砜红霉素高产菌株的选育

为提高红霉素发酵单位,考察了二甲基亚砜(DMSO)添加时间和体积分数对红霉素合成的影响,采用筛选自身代谢产物突变株的方法,将突变株进行常压室温等离子体(ARTP)诱变和耐受高浓度DMSO处理。结果显示,在36 h向发酵瓶中添加30000μg/m L红霉素,筛选得到化学效价比对照提高22.4%的菌株。DMSO最适添加时间为发酵48 h,最适添加剂量为0.2%,其可提高发酵单位10.1%。     

Transportation and handling stress of white suckers raised in cages

Changes in plasma cortisol concentrations were measured in juvenile white suckers, Catostomus commersoni (Lacepede), as a measure of their response to transportation (8 h) and chase challenge stressors. The study attempted to evaluate the ability of this species to withstand standard aquacultural husbandry practices. Plasma cortisol concentrations were elevated during and following transportation. Recovery from transportation (as plasma cortisol levels reached baseline values) was prolonged in fish transported under winter conditions compared with fish transported during the summer months. The plasma cortisol response to a 5 min chase challenge in well-fed juvenile white suckers was typically of 2 to 3 h periodicity with the peak values between 15 and 30 min. This pattern was similar in fish fed three commercial diets (although rates of recovery differed), and was unaffected by fasting. The return of plasma cortisol concentrations to baseline values following the chase-challenge stressor was prolonged in fasted groups. The results of this study showed that juvenile white suckers require several days to recover from transportation and under the acclimation conditions applied, the recovery was faster in the fish transported during the summer.     

Breed Differences in Natriuretic Peptides in Healthy Dogs

Background

Measurement of plasma concentration of natriuretic peptides (NPs) is suggested to be of value in diagnosis of cardiac disease in dogs, but many factors other than cardiac status may influence their concentrations. Dog breed potentially is 1 such factor.

Objective

To investigate breed variation in plasma concentrations of pro‐atrial natriuretic peptide 31‐67 (proANP 31‐67) and N‐terminal B‐type natriuretic peptide (NT‐proBNP) in healthy dogs.

Animals

535 healthy, privately owned dogs of 9 breeds were examined at 5 centers as part of the European Union (EU) LUPA project.

Methods

Absence of cardiovascular disease or other clinically relevant organ‐related or systemic disease was ensured by thorough clinical investigation. Plasma concentrations of proANP 31‐67 and NT‐proBNP were measured by commercially available ELISA assays.

Results

Overall significant breed differences were found in proANP 31‐67 (P < .0001) and NT‐proBNP (P < .0001) concentrations. Pair‐wise comparisons between breeds differed in approximately 50% of comparisons for proANP 31‐67 as well as NT‐proBNP concentrations, both when including all centers and within each center. Interquartile range was large for many breeds, especially for NT‐proBNP. Among included breeds, Labrador Retrievers and Newfoundlands had highest median NT‐proBNP concentrations with concentrations 3 times as high as those of Dachshunds. German Shepherds and Cavalier King Charles Spaniels had the highest median proANP 31‐67 concentrations, twice the median concentration in Doberman Pinschers.

Conclusions and Clinical Importance

Considerable interbreed variation in plasma NP concentrations was found in healthy dogs. Intrabreed variation was large in several breeds, especially for NT‐proBNP. Additional studies are needed to establish breed‐specific reference ranges.     

甲基汞对鲤鱼血浆渗透压及鳃丝Na＋－K＋－ATPase活性的影响

以水体甲基汞不同浓度（μｇ／Ｌ）分别染毒鲤鱼２４小时和１周。实验结果表明：在浓度高于５０μｇ／Ｌ染毒２４小时和浓度２０μｇ／Ｌ染毒１周时，多数染毒鱼的血浆Ｋ＋和Ｍｇ２＋浓度增高，Ｎａ＋和Ｃｌ－浓度下降，ＰＯ３－４值变化不明显。血浆Ｃａ２＋浓度仅在２００μｇ／Ｌ染毒２４小时和高于４０μｇ／Ｌ染毒１周时，染毒鱼的血浆Ｃａ２＋出现极显著下降。甲基汞量高于１００μｇ／Ｌ染毒２４小时和８０μｇ／Ｌ染毒１周，染毒鱼的血浆渗透压呈明显下降趋势。鳃线粒体Ｎａ＋－Ｋ＋－ＡＴＰａｓｅ活性仅在染毒２４小时浓度为２５μｇ／Ｌ和５０μｇ／Ｌ剂量时受到抑制。甲基汞还引起了血糖含量的明显增高。     

蛋用型鸡血浆极低密度脂蛋白浓度,肥度,生产性能之间的相关研究

以褐壳蛋鸡祖代母本种鸡为研究材料，用比浊法测定血浆极低密度脂蛋白浓度。试验结果表明，母鸡８１周龄腹脂重，腹脂率，鲜肝脂肪含量的变异系数分别高达４７％，３９％，４７％。表明这些性状在鸡群中未做过选择。血浆ＶＬＤＬ浓度与腹脂重，腹脂度，肝重，肝脂含量均呈正表型相关趋势。     

低温胁迫下弓葵幼苗膜脂过氧化及保护酶活性的变化

 低温胁迫下弓葵( Butia capitata Becc) 幼苗叶片的MDA 含量逐渐增加, 膜脂过氧化作用增强。- 8 ℃条件下的膜脂过氧化作用明显强于2 ℃。细胞膜透性在2 ℃条件下变化不大, - 8 ℃时则随低温胁迫时间延长而急剧上升, 细胞膜受到伤害。- 8 ℃胁迫下细胞保护酶SOD、POD 和CAT 活性短期(6 h) 内升高,然后下降, 24 h 以后3 种保护酶受到低温胁迫的严重抑制。在2 ℃胁迫下, SOD 活性在6 h 内变化不大, 随后下降; CAT活性变化趋势与- 8 ℃时相似, 但变化幅度较小; POD 虽也呈现先升后降的趋势, 但降幅明显小于升幅, 至48 h 时POD 活性仍维持较高水平。2 ℃低温胁迫不是抑制而是促进POD 活性的提高。