交配和温度对小地老虎雌蛾性信息素产生的影响

研究了交配和温度对小地老虎雌蛾性信息素产生的影响,结果表明,交配对性信息素各组分的滴度无显著影响,因此不影响小地老虎在下一暗期的再次求偶和交配.但环境温度对小地老虎性信息素的含量则有显著的影响,20～25℃最有利于小地老虎性信息素的生物合成,而低温和高温则均不利于小地老虎性信息素的正常产生与释放.     

小地老虎雄蛾对雌蛾性信息的EAG反应

利用触角电位记录（EAG）技术,测定了小地老虎Agrotis ypsilon (Rottemberg) 雄蛾对性信息素标准化合物Z7-12：Ac（A）、Z9-14：Ac（B）、Z11-16：Ac（C）、Z5-10：Ac（D）和Z8-12：Ac（E）的EAG反应。结果表明：这些标准化合物均能引起EAG反应,其中组分A（Z7-12：Ac）引起的反应最强,为5.65 mV,组分B（Z9-14：Ac）和C（Z11-16：Ac）居中; 组分D（Z5-10：Ac）的EAG反应值最小,为2.50 mV。二元混合物、三元混合物、四元混合物和全组分的EAG反应较高,其EAG反应值均显著高于单组分的反应值。三元混合物ABC的反应值最高,与5头雌蛾腺体的正己烷浸提液的EAG值相当。在使用剂量为0.01 ng～100 μg反应内,小地老虎雄蛾触角对性信息素各组分及其混合物的剂量反应曲线大致呈“S”形。从不同日龄雄蛾对标准化合物的反应中,发现在羽化后第3天达到最高值,之后则随日龄增加EAG反应降低。     

豆荚螟中国种群性信息素鉴定

利用气相色谱一质谱联用技术（GC—MS）和气相色谱与风洞技术对交配期的豆荚螟（Etiella zinckenella）处女雌蛾的腺体提取物进行定性分析并侦测其中的活性组分,最终确定豆荚螟性信息素的有效组分为顺9一十四碳烯醇乙酸酯（z9—14AC）、顺11一十四碳烯醇乙酸酯（Z11—14AC）、十四碳烯醇乙酸酯（14AC）,三种成分在腺体中的比例分别1：3：1的存在。     

小地老虎的交配行为和能力

在温度为(25±1)℃、相对湿度为70%±7%、光周期(L∶D)为14∶10h的条件下对小地老虎Agrotis ypsilon(Rottemberg)的交配行为和能力进行研究。结果表明:成虫在羽化后1d才进行交配。雄蛾和雌蛾都可以多次交配。交配能力受性比的影响很大,当1头雄蛾仅与1头雌蛾相处时,其交配能力低;当1头雄蛾与多于2头的雌蛾在一起时或1头雌蛾与多于2头的雄蛾在一起时,交配能力则显著增加。还讨论了该研究结果应用的可能性。     

用性信息素诱捕法大面积防治梨小食心虫的田间试验

1981至1982年,在辽宁省绥申县白梨产区用合成梨小食心虫性信息素诱捕法进行了大面积防治梨小食心虫Grapholitha molesta(Busck)的田间试验。防治面积分别为4,000公顷和5,400公顷。平均每公顷设15个性信息素诱捕器。化学防治区每年8—9月份喷两次农药,诱捕区不喷这两次农药。诱捕区梨小食心虫雌蛾的交配率比化防区下降74.2—82.9%;梨小卵的寄生率提高79.2%;梨小虫果率下降50.3—72.8%。     

用性信息素加农药诱杀器防治梨小食心虫的田间试验

在设计出性信息素加农药诱杀器后,以60、135、240、480个／km2诱杀器田间处理,看出以135个／km2诱杀器处理即有明显的防治效果。经在不同的虫口密度果园试验,以诱蛾量下降率、为害率和雌蛾交配率3项指标考察,该诱杀器1次挂出,在田间有效期达70～80天,取得了较理想防治效果。     

旋花蛾性信息素成分的鉴定

提取和鉴定了杂草田旋花Convolvulus arvensis的天敌旋花蛾Tyta luctuosa的性信息素主要成分;并应用风洞实验对雄蛾进行了测试。结果表明;腺体提取物和雌蛾求偶时所释放的主要性信息素成分均为2种化合物:顺-9-十四碳烯醛（Z9-14∶Ald）和顺-11-十六碳烯醛（Z11-16∶Ald）。腺体提取物中2种化合物的总量在个体间差异很大（22～167 ng）;但二者的比率相对稳定（Z9-14∶Ald/Z11-16∶Ald=0.3±0.15）。雌蛾所释放的性信息素量及比率在个体间也存在差异。每只雌蛾求偶时平均每小时释放94 ng Z9-14∶Ald和45 ng Z11-16∶Ald;平均比率为2.2。风洞实验结果显示;48%的雄蛾可被合成的性信息素混合物（0.4 μg Z9-14∶Ald, 2 μg Z11-16∶Ald）引诱完成逆风飞行并最终触及刺激源;而2种对照组（以求偶期雌蛾或性信息素腺体提取物为刺激源）的引诱率则分别为62%和44%。     

甜菜夜蛾性信息素鉴定及应用研究进展

近年甜菜夜蛾在我国大面积频频暴发 ,但缺少有效的防治手段。该文概述了有关甜菜夜蛾性信息素鉴定及应用方面的研究进展 ,认为利用性信息素可有效预测和防治甜菜夜蛾的发生和为害。我国应加强这一技术的研究和开发 ,使其尽快应用于农业生产尤其是无公害蔬菜生产中甜菜夜蛾的防治     

中国豆野螟性信息素腺体组份的化学结构鉴定

研究中国豆野螟Marucavitrata(Fabricius)性信息素腺体成分。分析证实(反,反)-10,12-十六碳二烯醛(E,E-10,12-16∶ALD)是中国豆野螟性信息素腺体的主要组份;同时利用GC和GC-MS发现(反,反)-10,12-十六碳二烯醇(E,E-10,12-16∶OH)和反-10-十六碳单烯醛(E-10-16∶ALD)也是中国豆野螟性信息素腺体的组份;三者在腺体中分别以51∶4∶45的比例存在。     

小地老虎雄性外生殖器的肌肉系统及神经分布

小地老虎Agrotis ypsilon Rott.雄性外生殖器由第8腹节的5对肌肉支持,它具有充分功能的抱器(clasper)和第9腹节的侧骨片,具有8对外生殖器特有的肌肉。具有一对由第9,10,11节原始腹部神经节的侧神经组成的成对的粗大神经干9+10+11,神经干的神经分支分布神经到外生殖器。     

A possible role of alanine for ammonia transfer between astrocytes and glutamatergic neurons

The metabolism of [U-(13)C]lactate (1 mM) in the presence of unlabeled glucose (2.5 mM) was investigated in glutamatergic cerebellar granule cells, cerebellar astrocytes, and corresponding co-cultures. It was evident that lactate is primarily a neuronal substrate and that lactate produced glycolytically from glucose in astrocytes serves as a substrate in neurons. Alanine was highly enriched with (13)C in the neurons, whereas this was not the case in the astrocytes. Moreover, the cellular content and the amount of alanine released into the medium were higher in neurons than astrocytes. On incubation of the different cell types in medium containing alanine (1 mM), the astrocytes exhibited the highest level of accumulation. Altogether, these results indicate a preferential synthesis and release of alanine in glutamatergic neurons and uptake in cerebellar astrocytes. A new functional role of alanine may be suggested as a carrier of nitrogen from glutamatergic neurons to astrocytes, a transport that may operate to provide ammonia for glutamine synthesis in astrocytes and dispose of ammonia generated by the glutaminase reaction in glutamatergic neurons. Hence, a model of a glutamate-glutamine/lactate-alanine shuttle is presented. To elucidate if this hypothesis is compatible with the pattern of alanine metabolism observed in the astrocytes and neurons from cerebellum, the cells were incubated in a medium containing [(15)N]alanine (1 mM) and [5-(15)N]glutamine (0.5 mM), respectively. Additionally, neurons were incubated with [U-(13)C]glutamine to estimate the magnitude of glutamine conversion to glutamate. Alanine was labeled from [5-(15)N]glutamine to 3.3% and [U-(13)C]glutamate generated from [U-(13)C]glutamine was labeled to 16%. In spite of the modest labeling in alanine, it is clear that nitrogen from ammonia is transferred to alanine via transamination with glutamate formed by reductive amination of alpha-ketoglutarate. With regard to the astrocytic part of the shuttle, glutamine was labeled to 22% in one nitrogen atom whereas 3.2% was labeled in two when astrocytes were incubated in [(15)N]alanine. Moreover, in co-cultures, [U-(13)C]alanine labeled glutamate and glutamine equally, whereas [U-(13)C]lactate preferentially labeled glutamate. Altogether, these results support the role proposed above of alanine as a possible ammonia nitrogen carrier between glutamatergic neurons and surrounding astrocytes and they show that lactate is preferentially metabolized in neurons and alanine in astrocytes.     

气相色谱-质谱定量检测水产品腐败菌群体感应DKPs信号分子

【目的】为了分析水产品腐败菌群体感应的新型信号分子二酮哌嗪(DKPs)化合物,建立一种简便、灵敏的气相色谱-质谱(GC-MS)定量检测方法。【方法】通过优化气相色谱和质谱条件、培养基和提取溶剂建立定量检测方法,确定Cyclo-(L-Pro-L-Gly)、Cyclo-(L-Pro-L-Leu)、Cyclo-(L-Leu-L-Leu)和Cyclo-(L-Pro-L-Phe)4种DKPs标准品的特征离子,并检测水产品腐败菌荧光假单胞菌(Pseudomonas fluorescens)和波罗的海希瓦氏菌(Shewanella baltica)中的DKPs。【结果】4种DKPs化合物在1-200 mg/L范围内线性良好,检测限为0.06、0.10、0.06和0.04 mg/L,定量限为0.16、0.18、0.14和0.12 mg/L,回收率为51.8%-88.5%,标准偏差为1.4%-8.3%。以LB培养基为细菌培养基,氯仿作为萃取溶剂,检测的DKPs含量较高。两种水产品腐败菌都检测到DKPs活性,主要种类为Cyclo-(L-Pro-L-Leu)和Cyclo-(L-Pro-L-Phe)。随着两种细菌的生长,培养上清中DKPs含量显著增加,在12 h达到最高。【结论】建立了检测细菌DKPs的GC-MS定量方法,具有较高精密度、准确度,能够准确定量分析4种DKPs的含量。为探究水产品特定腐败菌DKPs的调控机制奠定基础。     

Increased Nuclear DNA Oxidation in the Brain in Alzheimer's Disease

Abstract: Multiple lines of evidence indicate that oxidative stress is a contributor to neuronal death in Alzheimer's disease (AD). The oxidative damage that occurs to DNA may play a role in both normal aging and neurodegenerative diseases, including AD. This is a study of the oxidative damage that occurs in nuclear DNA in the brains of AD patients and cognitively intact, prospectively evaluated, age-matched control subjects. Nuclear DNA from frontal, temporal, and parietal lobes and cerebellum was isolated from 11 control subjects and 9 AD subjects, and oxidized purine and pyrimidine bases were quantitated using gas chromatography/mass spectrometry. Stable isotope-labeled oxidized base analogues were used as internal standards to measure 5-hydroxyuracil, 5-hydroxycytosine, 8-hydroxyadenine, 4,6-diamino-5-formamidopyrimidine (Fapy-adenine), 8-hydroxyguanine, and 2,6-diamino-4-hydroxy-5-formamidopyrimidine (Fapy-guanine). Statistically significant elevations of 5-hydroxycytosine, 5-hydroxyuracil, 8-hydroxyadenine, and 8-hydroxyguanine were found in AD brain compared with control subjects ( p < 0.05). There was an increased trend in the levels of Fapy-adenine in the AD brain, and Fapy-guanine showed a trend toward higher levels in control brains compared with AD. A generally higher level of oxidative DNA damage was present in neocortical regions than cerebellum. No significant correlation was observed between the oxidized bases and neurofibrillary tangle and senile plaque counts. Our results demonstrate that nuclear DNA damage by oxygen-derived radicals is increased in AD and support the concept that the brain is under increased oxidative stress in AD.     

A capillary gas chromatography/mass spectrometric method for the quantification of hydroxysteroids in human plasma

A specific and sensitive methodology for the quantitative determination of hydroxysteroids dehydroepiandrosterone and pregnenolone and their main metabolites in human plasma is described. Hydroxysteroids were extracted using methanol and steroids were further separated by reverse-phase high-performance liquid chromatography, allowing for minimization of the possible chromatographic interferences. Eluted fractions were collected, pooled, and analyzed by gas chromatography-mass spectrometry as trimethylsilyl ether derivatives. The quantification was performed with single-ion monitoring of the highly abundant m/z 129 or m/z 358 fragments. The combination of the chromatographic characteristics to the specific fragments ensured the selectivity and specificity of the method. Under these conditions the method was linear (typical R2 is superior to 0.98 for all hydroxysteroids studied) over the concentration range of 2 x 10(-9) to 10(-6)M with good precision and accuracy.     

Global analysis of metabolites in rat and human urine based on gas chromatography/time-of-flight mass spectrometry

Sediment in urine may contain low-molecular-weight compounds that should be included in the analysis. To date, no systematic investigation has addressed this issue. We investigated three primary factors that influence the extraction efficiency of metabolites during preparation of urine samples for metabolomic research: centrifugation, pH, and extraction solvents. Obtained with the use of gas chromatography/time-of-flight mass spectrometry (GC/TOFMS) technique and principal component analysis (PCA), our results indicate that (1) conventional centrifugation causes an apparent loss of some metabolites, indicating that urine samples for metabolomic research should not be centrifuged before procedures are undertaken to recover the metabolites; (2) pH adjustment has a large impact on the recovery of metabolites and is therefore not encouraged; (3) with design of experiment analysis, methanol and water yield the optimal extraction efficiency. Differences between rat and human urine were observed and are discussed. Ninety-nine metabolites identified in rat and human urine are presented. An efficient protocol is proposed for the pretreatment of urine samples.     

Potassium-Induced Release of Endogenous Morphine from Rat Brain Slices

Abstract: Endogenous morphine has been clearly demonstrated by gas chromatography/mass spectrometry in the brain, spinal fluid, adrenal glands, and liver of mammals. To clarify the role of endogenous morphine, its release from rat brain slices was studied in vitro in the presence of high potassium concentrations, with and without calcium in the medium. The perfusate was hydrolyzed, solid phase-extracted, and then analyzed by gas chromatography/mass spectrometry. Depolarization due to high potassium concentrations increased the release of the alkaloid manyfold with respect to the basal value, and the release was dependent on the presence of calcium in the medium. These results suggest that endogenous morphine might act as a neurotransmitter or neuromodulator in the rat CNS.     

Quantification of isoflavones and lignans in urine using gas chromatography/mass spectrometry

Phytoestrogens (isoflavones and lignans) are of increasing interest due to their potential to prevent certain types of complex diseases. However, epidemiological evidence is needed on the levels of phytoestrogens and their metabolites in foods and biological fluids in relation to risk of these diseases. We report an assay for phytoestrogens which is sensitive, accurate, and uses low volumes of sample. Suitable for epidemiological studies, the assay consists of a simple sample preparation procedure and has been developed for the analysis of five isoflavones (daidzein, O-desmethylangolensin, equol, genistein, and glycitein) and two lignans (enterodiol and enterolactone), which requires only 200 microl of urine and utilizes one solid-phase extraction stage for sample preparation prior to derivatization for GC/MS analysis. Limits of detection were in the region 1.2 ng/ml (enterodiol) to 5.3ng/ml (enterolactone) and the method performed well in the UK Government's Food Standards Agency-sponsored quality assurance scheme for phytoestrogens. For the first time, average levels of all the above phytoestrogens were measured in samples of urine collected from a free living population sample of women. Results show a large range in both the amount and the type of phytoestrogens excreted.