Metabolism of [ring-2,6-14]parathion in plant cell suspension cultures of carrot (Daucus carota), purple foxglove (Digitalis purpurea), soybean,thorn apple (Datura stramonium) and wheat (Triticum aestivum)

By means of standardized procedures, the metabolism of [ring-2,6-¹⁴C]-parathion was investigated in carrot (Daucus carota L.), purple foxglove (Digitalis purpurea L.), soybean (Glycine max Merrill cv. ?Mandarin’?, and Glycine max Merrill cv. ?Harosoy 63’? cultivated on B5 and Miller media, respectively), thorn apple (Datura stramonium L.), and wheat (Triticum aestivum L.) cell suspension cultures. In the wheat and soybean (Mandarin) cells only 2.9 and 8.9%, respectively, of the applied parthion remained unmetabolized after 48 h of incubation, while 51.2, 57.9, 60.3, and 62.4% of the unchanged parent were detected in the D. purpurea, D. Stramonium, carrot and soybean (Harosoy) cultures, respectively. In all suspensions, paraoxon and 4-nitrophenol were found as phase I metabolites, thus demonstrating that plant tissues can catalyse oxidative desulfuration and dearylation of parathion. 4-Nitrophenol was also glycosylated with glucose and possibly galactose. Further, as yet unidentified, metabolites indicated that bio-transformations had also occurred at the aromatic moiety. Large amounts of non-extractable residues were detected in the wheat suspension (38.3%), while the other cultures showed a lower incorporation of ¹⁴C into insoluble cell material (0.9-9.4%). For a prospective ecotoxicological evaluation of the metabolic fate of pesticides and xenobiotics in plants in general, the differential metabolic capacity of plant cell cultures and plants should be taken into account.     

Bone mineral changes in growing, pregnant and lactating cattle

Bone mineral content (BMC) was determined in one or two coccygeal vertebrae by dichromatic photon absorptiometry in two sets of cattle: A. This set consisted of six fattening bulls. Their increases of BMC and weights were closely correlated. However, BMC increased slightly more than weight. B. There were 28 cows in this set. BMC was measured during lactation and pregnancy. It was found that BMC increased during the dry period and decreased during early lactation. There were great individual variations in BMC, and the skeletal turnover seemed to be great.     

鱼类对饲料中糖的利用研究进展

糖类是鱼类饲料中廉价的能量源,然而,与陆生动物相比,鱼类对饲料中糖的利用能力较低。本文综述了这方面的最新研究进展,包括鱼类对饲料糖的利用能力与鱼饲料中糖的适宜含量、影响因素及鱼类的糖代谢机制。     

奶牛酒精阳性乳与自由基代谢及乳腺损伤关系的研究

对酒精阳性乳患牛衄清与乳清中的抗氧化指标进行了检测，从自由基代谢与损伤的角度探讨了酒精阳性乳的发病机理；同时检测了阳性牛血清与全乳中微量元素Zn、Cu、Mn、Fe的含量，分析了微量元素含量变化与自由基代谢的关系。试验结果显示阳性牛体内发生了过度的过氧化反应，机体总抗氧化能力下降，机体的扰氧化系统已不能有效地清除活性氧及代谢产物，过多的氧自由基可能对乳腺上皮分泌细胞细胞膜造成微损伤，从而引起乳腺细胞分泌异常乳。     

Interactions between dietary fatty acids and hepatic gene expression in livers of pigs during the weaning period

The aim of the present study was to evaluate the impact of dietary fatty acids (FA) during the weaning period on expression of genes involved in the oxidation and metabolism of FA (peroxisome proliferator-activated receptor (PPAR-), stearoyl-CoA-desaturase (SCD), Δ6-desaturase (D6D), acetyl CoA carboxylase (ACC) and fatty acid synthase (FAS)). Liver samples were obtained from littermates, either on day 28 of age just before weaning, or at day 56 after the 4 weeks ad lib. provision of 5% of either animal fat, fish oil or sunflower oil. In conclusion, genes involved in the regulation of FA conversion (SCD, D6D) were influenced by the n-6 to n-3 ratio, whereas the FA oxidation, as indicated by the expression of PPAR-, was highly likely regulated by the hepatic ratio between mono- and poly-unsaturated FA. Furthermore, weaning and/or age affected the hepatic expression of genes involved in FA synthesis and conversion, but not the expression of PPAR-.     

甲壳素、壳聚糖对家禽生产性能及脂肪代谢的影响

本文就甲壳素、壳聚糖的发现、来源、制备、结构和性质;甲壳素、壳聚糖对家禽生产性能及脂肪代谢的影响;甲壳素和壳聚糖的降脂机理及今后的研究发展方向进行综述。     

共轭亚油酸对五龙鹅生长发育和脂质代谢的影响

1日龄五龙鹅192只，随机分为4个处理，分别饲喂共轭亚油酸（CLA）水平为0．0、5．0、15．0和25．0g／kg的日粮，通过测定不同生长阶段的体增重（BWG）、采食量（FI）、料重比（F／G）、腹脂率（AFP），以及与脂质代谢有关血清生化指标，研究不同水平CLA日粮对五龙鹅生长发育和脂质代谢的影响。结果表明：在日粮中分别添加5．0g／kg和15．0g／kgCLA，对五龙鹅BWG无显著影响（P〉0．05），能够显著降低FI和F／G（P〈0．05）；显著降低AFP和血清甘油三酯（TG）、胆固醇（TC）、极低密度脂蛋白（VLDL）含量（P〈0．05或P〈0．01），增加了血清高密度脂蛋白胆固醇（HDL-C）含量和高、低密度脂蛋白胆固醇之比（HDL-C／LDL-C）（P〈0．05）。日粮中添加25．0g／kgCLA，极显著地降低了FI和AFP（P〈0．01），对血清TG、TC、HDL-C、VLDL含量和HDL-C／LDL-C的影响差异不显著（P〉0．05）。适宜添加CLA对五龙鹅的生长发育和脂质代谢具有很好的促进和调节作用，即在五龙鹅的整个生长期内，CLA添加量不高于15．0g／kg时，不但能在不影响BWG的前提下提高饲料利用率，而且能够通过降低脂肪沉积和调节脂质代谢起到预防动脉粥样硬化的作用；但过多添加CLA（25．0g／kg）会使五龙鹅的生长发育受到抑制。     

Status of black grass (Alopecurus myosuroides) resistance to acetyl-coenzyme A carboxylase inhibitors in France

We assessed the contributions of target site‐ and non‐target site‐based resistance to herbicides inhibiting acetyl‐coenzyme A carboxylase (ACC) in Alopecurus myosuroides (black grass). A total of 243 A. myosuroides populations collected across France were analysed using herbicide sensitivity bioassay (24 300 seedlings analysed) and ACC genotyping (13 188 seedlings analysed). Seedlings resistant to at least one ACC‐inhibiting herbicide were detected in 99.2% of the populations. Mutant, resistant ACC allele(s) were detected in 56.8% of the populations. Among the five resistant ACC alleles known in A. myosuroides, alleles containing an isoleucine‐to‐leucine substitution at codon 1781 were predominant (59.5% of the plants containing resistant ACC alleles). Comparison of the results from herbicide sensitivity bioassays with genotyping indicated that more than 75% of the plants resistant to ACC‐inhibiting herbicides in France would be resistant via increased herbicide metabolism. Analysis of herbicide application records suggested that in 15.9% of the populations studied, metabolism‐based resistance to ACC‐inhibiting herbicides was mostly selected for by herbicides with other modes of action. Our study revealed the importance of non‐target site‐based resistance in A. myosuroides. Using herbicides with alternative modes of action to control populations resistant to ACC‐inhibiting herbicides, the recommended management approach, may thus be jeopardised by the widespread occurrence of metabolism‐based resistance mechanisms conferring broad‐spectrum cross‐resistance.     

VE在硒缺乏动物自由基代谢中的作用

为探讨ＶＥ在硒缺乏动物自由基代谢中的作用及添加ＶＥ对自由基代谢的影响,本试验采用低硒（低于１０－９）、补ＶＥ（１０－４）日粮饲喂小鼠,并对动物增重,血液、肝组织内丙二醛（ＭＤＡ）、硒谷胱甘肽过氧化物酶（Ｓｅ－ＧＳＨ－Ｐｘ）及自由基（ＦＲｓ）水平进行了系统检测。试验发现,添加ＶＥ除可阻止缺硒所致的动物生长迟缓外,还可明显降低相关组织内ＭＤＡ的含量,但它并不直接影响Ｓｅ－ＧＳＨ－Ｐｘ的活力。试验结果表明,ＶＥ主要通过对机体脂质过氧化反应的抑制作用及其对自由基所致膜结构损伤的修复而参与机体自由基代谢,在硒缺乏状态下,它能与硒协同作用而影响病程发展和疾病转归。     

南方红豆杉生物技术研究进展

南方红豆杉是中国特有珍贵树种,集药用、材用与观赏等多种价值于一体。主要对南方红豆杉组织培养、细胞培养、分子标记与基因工程等生物技术研究方面的现状进行了综述,进一步阐述了南方红豆杉生物技术研究中存在的问题,并提出了应重点开展的研究领域。