兽药类环境内分泌干扰效应及评价研究进展

兽药在保障动物健康、提高畜禽产品质量尤其在畜牧业集约化发展等方面起着至关重要的作用,然而兽药和饲料添加剂的大量使用成为生态环境污染和人体健康损害的一个重要因素。研究表明许多抗生素类和激素类兽药是典型的环境内分泌干扰物,通过多种方式干扰生物体雄激素、雌激素、甲状腺激素等内分泌过程,产生内分泌干扰效应。本文介绍了典型兽药的污染现状及其内分泌干扰效应研究最新进展;以环境内分泌干扰物的最新研究方法为基础,较全面地评述了可用于兽药类内分泌干扰物的快速筛选、检测及评价方法,并对该领域未来研究提出了展望和建议,以期为环境和农业等管理部门制定兽药的使用、排放、管理政策提供科学依据。     

植物激素对平菇茵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.     

环境激素的危害与防治研究

环境激素是继臭氧层破坏、温室效应之后的又一全球性环境问题,对环境激素污染问题的认识、研究与防治已经开始受到全球的重视。环境激素直接影响生物多样性,危及生物安全,对人类未来构成潜在威胁。环境激素发挥着类似激素的作用,它们进入体内,扰乱了激素的正常分泌,使人和动物的生理程序发生紊乱,导致生殖、免疫等功能发生障碍,对机体、后代或种群引起可逆性或不可逆性生物学效应。本文就环境激素的种类、作用机理、防治对策等方面进行了综述。     

UV-B辐射胁迫对大豆幼苗内源激素的影响

为了探索UV-B辐射胁迫对大豆幼苗内源激素的影响,试验以大豆幼苗为材料,采用水培实验的方法研究了UV-B辐射胁迫对大豆幼苗生长素(IAA)、生长素氧化酶(IAAO)、脱落酸(ABA)、赤霉素(GA)的影响.结果表明,UV-B辐射(T1:0.15W.m-2和T2:0.45 W.m-2)胁迫下,大豆幼苗IAAI、AAO、ABA、GA含量在胁迫期(1~5 d)和恢复期(6~11 d)分别呈现"先下降后有所回升"、"先升后降再升"、"先升后降"、"下降"趋势.进而从内源激素层面表明了UV-B辐射伤害大豆幼苗的机理效应。     

HPLC/MSn法鉴定环境激素邻苯二甲酸丁基苄酯在小鼠尿中的代谢产物

应用HPLC-MSⁿ方法,研究了邻苯二甲酸丁基苄酯在小鼠尿液中的代谢产物,并对尿中推测的代谢物和标准品分别进行HPLC-UV和二级全扫描质谱（MS²）分析,结果在尿中发现了6个代谢产物,分别为邻苯二甲酸、马脲酸、邻苯二甲酸单丁酯、邻苯二甲酸苄酯、邻苯二甲酸单丁酯葡萄糖醛酸结合物及邻苯二甲酸苄酯葡萄糖醛酸结合物.推断环境激素邻苯二甲酸丁基苄酯在小鼠体内的代谢途径为原形首先水解生成邻苯二甲酸单丁酯、邻苯二甲酸苄酯、邻苯二甲酸,部分邻苯二甲酸发生脱羧反应生成苯甲酸,苯甲酸再与内源性物质甘氨酸结合成马脲酸,邻苯二甲酸单丁酯、邻苯二甲酸苄酯和内源性β-D-葡萄糖醛酸结合,生成水溶性较大的邻苯二甲酸单丁酯葡萄糖醛酸结合物和邻苯二甲酸苄酯葡萄糖醛酸结合物.     

The effects of bisphenol A on sex hormone levels of F0 female rats and F1 male rats during weaning period

The effects of bisphenol A (BPA) were examined on sex hormones of F1 generation male rats during weaning period. Female rats were exposed to BPA from day 0 after pregnancy to the weaning period at doses of 50, 100, or 200 mg kg^?1. The sex hormone levels of F1 generation male rats were determined. This study shows that F0 generation female rats fed with 200 mg kg^?1 BPA had a significantly higher serum prolactin (PRL) levels at the end of weaning. Significantly higher levels of serum estradiol (E₂) were also found in female rats fed 100 or 200 mg kg^?1 BPA. Serum levels of E₂ in F1 male generation rats were higher in treatment groups compared to control groups while serum testosterone (T) levels were lower. Follicle stimulating hormone (FSH) in F1 generation rats fed 200 mg kg^?1 was markedly decreased. The relative testicular weights were significantly less in 100 and 200 mg kg^?1 BPA groups. BPA was found to alter the sex hormone levels in F1 male rats during weaning period and thus disrupted endocrine functions.     

Time-dependent effects of pentabrominated diphenyl ethers on gonadal hormone and genital system histology in male rats

The aim of this study was to examine the effects of pentabrominated diphenyl ethers (PBDE) on gonadal hormone levels and histology in male rats. Rats in treatment groups were orally gavaged with PBDE-99 at a dose of 120 mg?kg^?1 for 5, 15, 30, or 45 days, while controls received equal volume of corn oil. In the treated groups, changes were not found on day 5. On day 15, testicular weight increased, serum levels of estradiol (E₂) decreased, proliferation cell nuclear antigen (PCNA) positive expression was reduced, and sperms within the seminiferous tubules were damaged. On day 30, testicular weight was further increased, serum levels of testosterone (T) and E₂ decreased, PCNA positive expression was further reduced, some primary spermatocytes cells did not express, and seminiferous epithelium was degenerated. At 45 days, testicular weight decreased, levels of T, E₂ concentrations were lower, histopathologic examination revealed severe degeneration of seminiferous epithelium, and only a part of spermatogonial cells were expressed. The earliest alterations occurred at 15 days. PBDE-99 produced time-dependent reduction of gonadal hormone levels and degeneration of gonadal system histology.     

Effect of anti-juvenile hormone agent,KK-42 on the incorporation rate of radioactive glycine and biosynthesis of silk proteins of silkworm,Bombyx mori L.

The effects of anti-juvenile hormone agent, KK-42 on incorporation rate of radioactive glycine in cocoon crop production and biosynthesis of silk proteins of silkworm, Bombyx mori L. were studied in a popular bivoltine silkworm hybrid, Xinhang (Chinese) × Keming (Japanese). Administration of KK-42 on first day larvae of fourth instar induced 100% trimolters, and the total larval duration was shortened by four days, which has marked advantages in sericulture. The impact of KK-42 on enhanced incorporation rate of radioactive glycine, cocoon weight, RNA content, and fibroin content was significant compared to control, which leads to superior quality of silk. This has a significant economic importance in the reeling industry.     

EEDs对鱼类性激素合成途径干扰作用研究进展

环境内分泌干扰物(environmental endocrine disruptors,EEDs)是一类可以改变生物体内激素的合成、释放、运输、代谢、结合、作用或清除等一系列生物过程的外源物质。性激素的生物合成需要一系列酶的参与,体内和体外研究表明,性激素合成途径中的类固醇生成酶是EEDs通过非性激素受体介导途径发挥内分泌扰乱作用的重要靶点,性激素合成途径的扰乱可能导致生物体生殖系统受损。本文综述了EEDs对鱼类性激素合成底物和类固醇生成酶的影响、信号转导机制及其生殖危害;并对性激素合成途径中促性腺激素调控机理、多种转录因子间的相互作用、不同物种间类固醇生成酶的差异以及各内分泌轴线的相互作用研究进行了展望,以期为EEDs通过非性激素受体介导途径发挥内分泌干扰效应的机制研究提供思路。     

铬胁迫下不同品种小麦萌发和内源激素的变化

采用K2(CrO4)3溶液,设5个浓度,对3种不同抗性的小麦品种(新麦19、矮抗58和豫麦18)进行萌发期胁迫处理,研究了幼苗的发芽势、发芽率、根长、芽长及内源激素含量的变化.结果表明:(1)随着铬浓度的增加,发芽势、发芽率和芽长均基本呈"先升后降"趋势;(2)同一浓度铬处理下,发芽率、发芽势和芽长从大到小的顺序依次为:新麦19、矮抗58、豫麦18,根长从大到小的顺序为:豫麦18、新麦19、矮抗58;(3)150 mg L-1的铬胁迫下,IAA与ABA在小麦幼苗、幼根中含量降低,在籽粒中含量升高,其中新麦19籽粒和根芽中ABA含量均高于其他品种的;(4)不同浓度铬胁迫下,IAA/ABA值在新麦19中最低,变化幅度最小,新麦19表现出较强的抵抗铬胁迫能力.图3表1参20