排序方式: 共有26条查询结果,搜索用时 15 毫秒
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[目的]通过建立粪便中生殖激素含量的测定方法,为研究藏羚羊的繁殖特征奠定基础。[方法]以2-(11H-苯﹝α﹞咔唑)-乙基肼基甲酸酯(BCECH)为柱前衍生化试剂,探讨皮质醇、皮质酮、睾酮和孕酮4种类固醇激素衍生物的最佳色谱分离条件。通过比较4种类固醇激素标准品出峰时间,确定粪样中目标物质峰。[结果]最优衍生条件为:以乙腈为衍生化溶剂,以三氯乙酸为催化剂,衍生化温度65℃,衍生试剂用量为总摩尔类固醇的10倍以上。在建立的色谱条件下,藏羚粪样中4种类固醇激素含量色谱图有较多的杂质峰,表明粪样中的成分很复杂。[结论]该研究建立了藏羚羊粪便中类固醇激素高效液相色谱的分析方法,实现了藏羚粪便中4种类固醇化合物的定量测定。 相似文献
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B. Lal 《Fish physiology and biochemistry》2007,33(4):455-462
Numerous studies are available reporting the effects of pesticides on reproductive activity in Indian fishes. The majority
of these reports deals with histopathological changes in gonads and endocrine glands involved in the regulation of reproduction
following treatment with different pesticides. Pesticides are reported to cause degenerative changes in gonads and arrest
gametogenic processes either by acting directly on the gonads or by interfering with the secretory activity of the hypothalamo-hypophyseal-gonadal/thyroid
axis that regulates various reproductive events. Secretion of hormones such as gonadotropin-releasing hormone (GnRH), gonadotropin,
growth hormone, adrenocorticotropic hormone (ACTH), testosterone, estrogens, 17,20β-dihydroxyprogesterone and thyroid hormones
are in general lowered, leading to cessation of gametogenesis, vitellogenesis, oocyte maturation, ovulation, spermiation,
etc. Adverse effects of pesticides have also been demonstrated on fecundity, fertilization, hatching, and postembryonic development.
The effects are highly variable and depend on the nature, dose, and mode of application of the pesticides. 相似文献
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Total lipid extracts from an acid andic soil profile located on Madeira Island (Portugal) were analysed using gas chromatography (GC) and GC-mass spectrometry (GC/MS). The profile was covered mainly by grass. Bulk soil characteristics determined included soil pH (H2O) ranging from 4.5 to 4.0 and TOC, ranging from 84 to 30 g kg−1. A decrease of the contribution of lipids per TOC with depth was observed. The absence of typical bacterial markers might be an indication for reduced bacterial activity, most likely related to the low soil pH and the presence of Al and Fe (oxides). The distribution observed in the top layer with a dominant C26n-alkanol, steroids and triterpenoids, reflected mainly an input by grass leaves. A strong decrease in both relative and absolute concentration of these leaf-derived compounds was observed when comparing the litter layer with the mineral soil. The presence of C22-C32n-alkanoic acids, C22-C26 ω-hydroxy acids, C31n-alkane and C22-C32n-alkanols observed in the sub-soil is indicative of an important contribution by (grass) roots. In summer, a signal most likely reflecting the leaching of microbially derived products from the litter and/or aerial vegetation at the surface was observed. 相似文献
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Khalijah Awang Xe-Min Loong Kok Hoong Leong Unang Supratman Marc Litaudon Mat Ropi Mukhtar Khalit Mohamad 《Fitoterapia》2012
A study on the leaves of Aglaia exima led to the isolation of one new and seven known compounds: six triterpenoids and two steroids. Their structures were elucidated and analyzed mainly by using spectroscopic methods; 1D and 2D NMR, mass spectrometry, UV spectrometry and X-ray. All the triterpenoids and steroids were measured in vitro for their cytotoxic activities against eight cancer cell lines; lung (A549), prostate (DU-145), skin (SK-MEL-5), pancreatic (BxPC-3), liver (Hep G2), colon (HT-29), breast (MCF-7) and (MDA-MB-231). The new cycloartane triterpenoid, 24(E)-cycloart-24-ene-26-ol-3-one 1, showed potent cytotoxic activity against colon (HT-29) cancer cell line (IC50 11.5 μM). 相似文献
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利用活菌菌饼法和滤纸片法研究筛选64株海南粗榧内生真菌对罗非鱼源无乳链球菌的抑菌活性,并对活性菌株的代谢产物化学成分进行初步测试。菌饼试验结果显示,11株海南粗榧内生真菌对无乳链球菌具有明显抑制作用,占总菌株数的17.2%,抑菌圈在Φ(8.7±0.3~16.2±0.2)mm间。滤纸片试验结果显示,12株具有明显抑制作用,占总菌数的18.8%,抑菌圈在Φ(8.7±0.3~28.2±0.4)mm间。2种方法的最高活性菌株不一致,但最高活性菌株(B30、F52)和同时显示较高活性的菌株(B14、B30、B32、F7、F52)被测出都含有甾体及三萜类化合物。根据结果推测,对无乳链球菌有显著抑制作用的菌株可能含有甾体及三萜类物质。结果为深入研究内生真菌对罗非鱼无乳链球菌的抑制奠定基础,也为生物防治罗非鱼病害提供有益借鉴。 相似文献
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Mariko KUSE Hwa-Yong LEE Tomas J. ACOSTA Takuo HOJO Kiyoshi OKUDA 《The Journal of reproduction and development》2013,59(4):346-352
Cortisol (Cr), the most important glucocorticoid (GC), is well known to suppress uterine
prostaglandin F2α (PGF) production. However, the details of the regulatory mechanisms
controlling the cyclic changes in endometrial PGF production remain unclear. Here we
investigated the expression of the GC receptor (GC-Rα), the actions of cortisol throughout
the estrous cycle and the regulatory mechanism of GC-Rα in the bovine endometrium. The
levels of GC-Rα protein were greater at the mid-luteal stage (Days 8–12) than at the other
stages. Cr more strongly suppressed PGF production at the mid-luteal stage than at the
follicular stage. GC-Rα expression was increased by progesterone (P4) but decreased by
estradiol-17β (E2) in cultured endometrial stromal cells. The overall results suggest that
ovarian steroid hormones control the cyclic changes in endometrial PGF production by
regulating GC-Rα expression in bovine endometrial stromal cells. 相似文献
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In order to evaluate manipulation of spawning time as a potential means to extend 0+ Atlantic salmon (Salmo salar) smolt production in Tasmania, Australia, female salmon were exposed to a natural/simulated natural (42°S) photoperiod or an advanced (L:D 9:15) photoperiod from the austral summer solstice (20 December) under natural or advanced (~ 6 °C below natural temperature) temperature conditions. In late summer (26 February) injections of a commercial LHRHa preparation or vehicle (propylene glycol) commenced. Regular ovulation checks were conducted and ova were fertilised using milt from LHRHa-injected males held under matching photo-thermal conditions. Plasma levels of 17β-estradiol (E2) and testosterone (T) were monitored and reproductive success (cumulative % ovulation, % fertilisation and % survival to the eyed-egg stage) was recorded. Ovulations commenced first (09 March) in LHRHa-treated fish that experienced advanced photoperiod and thermal regimes whereas sham-treated fish exposed to natural photoperiod and temperature conditions where the last to ovulate (22 May-08 June). Treatment-related sequential changes in the timing of ovulations were reflected by sequential advances in the timing of peaks in plasma levels of E2 and T. The fertilisation of ova from LHRHa-treated fish that experienced advanced photoperiod and thermal regimes was significantly reduced (~ 52%) relative to all other treatments (> 80%) but there were no significant treatment-related differences in the survivals of eggs to the eyed stage (~ 50-90%). Consequently, a maximum advance in the timing of median ovulation of 71 days and commercially acceptable eyed-egg yields were generated, demonstrating that combinations of photoperiod, thermal and hormone treatments may be employed to significantly extend spawning and thereafter increase the availability of 0+ smolts for grow-out. 相似文献
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A new D:B-friedoolean-type triterpene, 3β-acetoxyglutin-5(10)-en-6-oxo (1), together with seventeen known compounds (2-18) was isolated from the roots of Scorzonera austriaca. Their structures were elucidated mainly by NMR and HR-ESI-MS, as well as on comparison with the reported data. Cytotoxicities of compounds 2, 4, 6, 10-14 and 16 against selected cancer cells of human promyelocytic leukemia (HL-60) and human hepatoma (BEL-7404) were measured in vitro. 相似文献