ELISA法检测鸡胚中抗生素残留量的研究及其应用

用ELISA法测定氨苄青霉素、氯霉素在流感疫苗生产用海兰白鸡鸡胚中的残留。实验通过比较空白组0d龄全鸡胚和给药组0d龄全鸡胚中氨苄青霉素、氯霉素的残留量,说明了饮水给药的方法能够建立抗生素残留的动物模型。通过比较10d龄鸡胚尿囊液、卵黄中氨苄青霉素、氯霉素的残留量,说明尿囊液中的残留量明显高于卵黄。通过绘制残留曲线,可以看出氨苄青霉素、氯霉素在海兰白鸡体内蓄积迅速,却消除缓慢。通过实验初步摸索出了氨苄青霉素和氯霉素在鸡胚中的分布、代谢及残留规律,获得了部分生产用鸡胚尿囊液的抗生素残留量数据,为进一步控制流感疫苗生产用鸡胚质量提供技术保障。     

三种蜂王浆蛋白质的营养评价

采用国际上通用的营养价值评价方法,全面评价了中蜂王浆、意蜂王浆和卡蜂王浆蛋白质的营养价值。三种王浆的必需氨基酸含量分别占其氨基酸总量的42.88%,40.98%和42.72%,含硫氨基酸为第一限制氨基酸。蛋白质的化学评分(CS)、氨基酸评分(AAS)、必需氨基酸指数(EAAI)、生物价(BV)、营养指数(NI)和氨基酸比值系数分(SRCAA)计算结果表明,三种蜂王浆都是良好的蛋白源,但中蜂王浆蛋白质的营养价值高于意蜂王浆和卡蜂王浆,明显与常规品质评价指标10-HDA的含量高低顺序不同。     

蔬菜中农药残留检测技术研究进展

对目前蔬菜中农药残留分析检测方法及其前处理过程以及快速检测技术作了综述。固相萃取(SPE)、超临界流体萃取(SFE)等新的萃取方法已逐渐代替了液-液萃取(LLE)等传统提取方法。色谱技术是农药残留分析中的重要手段。毛细管气相色谱(CGC)、高效液相色谱(HPLC)及其联用技术是现阶段农药残留分析中的主要检测方法。并指出了今后该领域的研究方向。     

氯霉素酶联免疫检测方法的研究

通过活化琥珀氯霉素的羧基使其与蛋白联结合成了免疫抗原 ,并制备了氯霉素的多克隆抗体 ,建立了氯霉素直接竞争酶联免疫检测方法 ,检测时间在 1h之内。抗体的ELISA效价达 3.2× 10 5以上 ,I50 为 12 .9ng ml,检测范围为 0 .2 4ng ml- 6 78.8ng ml。抗体与琥珀氯霉素的交叉反应率为 174 .5 4 % ,与其它抗生素的交叉反应率均小于 0 .0 1%。牛奶样品中平均添加回收率为10 6 .5 6 %。所建立的氯霉素酶联免疫检测方法达到了我国牛奶氯霉素残留限量 0 .2 5ng ml的要求 ,为国产的商品化氯霉素酶免疫检测试剂盒的研制奠定了基础     

QuEChERS-液相色谱-串联质谱法测定南药高良姜中31种农药残留

高良姜是药食两用资源,但有关其农药残留的研究较少。通过优化QuEChERS前处理方法并结合超高效液相色谱-三重四极杆串联质谱(UPLC-MS/MS)技术建立了高良姜中31种农药残留的测定方法。目标化合物由乙腈提取后在电喷雾电离(ESI)源多反应监测(MRM)正离子模式下检测,基质匹配外标法进行定量分析。31种农药在各自的线性范围内呈现良好的线性关系(R~20.99),检出限(LODs)和定量限(LOQs)分别为0.015～0.08 mg/kg和0.05～0.25 mg/kg。在三个添加水平下,31种农药的平均加标回收率在71.52%～116.38%,相对标准偏差(RSD)为0.07%～12.87%。24批高良姜样品共检出了甲基硫菌灵、水胺硫磷、杀虫丹等5种农药残留。该方法快速简便、净化效果好,可应用于高良姜中多农药残留的检测。本研究为高良姜在药食两用方面应用的安全性奠定了数据基础。     

HPLC法测定红豆杉细胞培养物中的α-萘乙酸

建立高效液相色谱法检测红豆杉细胞培养物中萘乙酸残留的方法。细胞培养液直接用二氯甲烷萃取,鲜细胞用99%乙醇浸提后,再用二氯甲烷萃取,分别得到回收率均达到87%以上的萘乙酸试样,色谱分离采用Nova-pak C18柱,柱温30℃,紫外检测波长为281 nm,进样体积5μL,外标法定量。结果显示萘乙酸的质量在0.001～0.125 ug(R=0.9998)范围内与色谱峰面积呈良好的线性关系,萘乙酸在细胞培养液中的检出限为0.02 mg/L,在鲜细胞中的检出限为0.2 mg/kg。本方法简便快速、灵敏度高,可监测红豆杉细胞培养生产紫杉醇过程中萘乙酸的残留。     

睾酮人工抗原的合成及酶联免疫方法的建立

为检测食品中睾酮的残留,合成睾酮人工抗原并建立一种用于检测睾酮的酶联免疫方法(ELISA)。通过混合酸酐法将肟化的睾酮与鸡卵清蛋白偶联,合成人工包被抗原,与睾酮单克隆抗体竞争结合,根据光密度(OD)值对睾酮定量。结果表明,经紫外吸收、红外光谱、SDS-PAGE电泳验证人工抗原合成成功,建立的间接竞争酶联免疫标准曲线线性范围为1～25μg/L,最低检测限为0. 261 7μg/L。对该检测方法进行稳定性测定,将储存3、7、10、14 d的试剂盒进行标准品测定,所得批间差异均小于5%。同时进行样品加标回收试验,平均加标回收率在87. 51%～102. 83%,说明建立的睾酮ELISA检测具有很高的准确度,可以应用于实际样品中睾酮的检测。本研究为进一步开发睾酮酶联免疫检测试剂盒检测食品中睾酮残留奠定基础,为保障我国肉制品质量安全提供一种有效的技术手段。     

应用益生菌监测牛奶抗生素残留

目的探索肠道益生菌在抗生素残留监测中的应用并建立牛奶中多种抗生素残留的微生物学筛检方法。方法厌氧培养分离健康人肠道益生菌并用纸片扩散法检测其对四环素、红霉素、青霉素、庆大霉素、氯霉素和万古霉素的敏感性。根据药敏结果及产酸能力选择工作菌株。建立基于厌氧培养的益生菌抗生素残留筛检方法并优化实验条件,测定其对不同抗生素的检测限,通过测定加标模拟阳性和阴性样本计算方法的准确性。结果短双歧杆菌A2可用于牛奶抗生素残留筛检。应用短双歧杆菌筛检牛奶中四环素、红霉素和青霉素的检测限分别为80μg/L、40μg/L和3μg/L,检测加标四环素、红霉素和青霉素的牛奶样品准确性为100.0%、92.5%和90.0%,无假阴性结果。结论应用益生菌的筛检方法敏感、简便,对环境和操作者友好,适用于监测牛奶中四环素、红霉素和青霉素等多种抗生素。     

一种快速测定植物油中的草铵膦、草甘膦及其代谢物氨甲基膦酸残留的方法

笔者建立了分散液液萃取非衍生-超高液相色谱-串联质谱快速检测植物油中的草铵膦、草甘膦及其代谢物氨甲基膦酸残留的方法。样品用正己烷溶解分散,再通过乙腈-水(体积比1∶1)液液萃取,以5 mmol/L、p H为12. 0的乙酸铵-氨水溶液和乙腈为流动相,梯度洗脱,Dikma Polyamino氨基柱(2. 0 mm×150 mm,5μm)色谱分离,采用电喷雾离子源负离子模式多反应监测(MRM)模式进行质谱测定。通过基质外标法定量,进而降低样品基质效应的影响。结果表明:在去除样品基质干扰方面取得良好的效果,草铵膦、草甘膦、氨甲基膦酸的线性范围分别为0. 005～0. 1、0. 01～0. 2、0. 01～0. 2 mg/L,相关系数(R2)均大于0. 999;检出限分别为0. 01、0. 02、0. 02 mg/kg,定量限为0. 02、0. 04、0. 04 mg/kg;草铵膦、草甘膦、氨甲基膦酸在3档加标水平下的回收率在73. 2%～89. 6%,相对标准偏差(RSD)在4. 86%～9. 24%。本方法的前处理样品无需衍生,简便、快捷、高效、准确可靠,可用于植物油中草铵膦、草甘膦及氨甲基膦酸的快速检测。     

蒙药材多叶棘豆中五种微量元素的形态分析

本文采用水煎法对蒙药材多叶棘豆中微量元素进行提取,并分别用微孔滤膜分离技术、大孔吸附树脂柱分离法、萃取法等分离方法对水煎液中元素各形态进行分离。利用FAAS法测定了原药材以及水煎液各形态中Cu、Zn、Mn、Fe和Ca五种微量元素含量并进行了形态分析。分析结果表明,水煎液中五种元素的总提取率在41.7%～87.0%,残留率在9.1%～26.4%,可溶态百分率在16.6%～80.0%,可溶态中五种元素的有机态与无机态的比例为36.9%～250%;该测定方法对各元素的加标回收率在90.3%～113.7%。多叶棘豆水煎液可溶态中Zn、Mn、Fe、Ca元素是以亲水性有机结合形态为主,Cu元素以无机离子型为主,多种形态共存的复杂体系。     

Land,livestock, and livelihoods: Changing dynamics of gender,caste, and ethnicity in a Nepalese Village

Over the past 10 years, Ghusel VDC, Lalitpur District has moved from primarily subsistence agriculture into the wider cash economy aided by the Small Farmers' Development Program (SFDP), which provides credit to farmers mainly for the purchase of buffalo for milk production, and by the National Dairy Corporation, which supports local dairy cooperatives. Analysis reveals that buffalo-keeping and milk sales are increasing the well-being of many households, while at the same time creating new inequalities in gender roles and responsibilities, greater inequities between Brahmin and Tamang residents in Ghusel, and placing pressures on the ecosystem for increased supplies of fodder and fuelwood. Evidence suggests that there is critical, need for attention to the social, and particularly gender-based, implications of maintaining livestock for milk sales and to the ecological underpinnings of this livelihood system.     

Influence of Fluoride on Rat Kidney Antioxidant System: Effects of Methionine and Vitamin E

The aim of the study has been to determine and compare the influence upon the kidney antioxidative system, exercised by administration of vitamin E, and vitamin E in combination with methionine, under conditions of oxidative stress induced by sodium fluoride. The experiment was carried out on Wistar FL rats (adult males) that, for 35 days, were administered water, NaF, NaF with vitamin E, or vitamin E with methionine (doses: 10 mg NaF/kg of body mass/24 h, 3 mg vitamin E per 10 μl per rat for 24 h, 2 mg methionine per rat for 24 h). The influence of administered sodium fluoride and antioxidants upon the antioxidative system in kidney was examined by analyzing the concentration of malondialdehyde (MDA) and the activity of the most important antioxidative enzymes (SOD, total and both its isoenzymes, GPX, GST, GR, and CAT). The studies carried out confirmed the disadvantageous effect of the administered dose of NaF upon the antixodiative system in rats (increase in the concentration MDA, decrease activity of all antioxidative enzymes). The administration of vitamin E increased the activity of studied enzymes with the exception of glutathione reductase GR; it also reduced the procesess of lipid peroxidation. It has been found that combined doses of vitamin E and methionine were most effective in inhibiting lipid peroxidation processes. The results confirmed the antioxidative properties of methionine.     

Identification of specific binding sites for leukotriene C4 in human fetal lung

Specific leukotriene C₄ (LTC₄) binding sites were identified in membrane preparations from human fetal lung. Specific binding of [³H]-LTC₄ represented 95 percent of total binding, reached steadystate within 10 minutes and was rapidly reversible upon addition of excess unlabeled LTC₄. Binding assays were performed at 4°C under conditions which prevented metabolism of [³H]-LTC₄ (80 mM serineborate, 10 mM cysteine, 10 mM glycine). Under these conditions, greater than 95 percent of the membrane bound radioactivity, as analyzed by high performance liquid chromatography, co-eluted with the LTC₄ standard. Computer-assisted analyses of saturation binding data showed a single class of binding sites with a dissociation constant (K_d) of 26 + 6 nM and a density (B_max) of 84 ± 18 pmol/mg protein. Pharmacological specificity was demonstrated by competition studies in which specific binding of [³H]-LTC₄ was displaced by LTC₄ and its structural analogs with inhibition constants (K_j) of 10 to 30 nM, whereas LTD₄, diastereoisomers of LTD₁, LTE₄ and the end organ antagonist FPL 55712 were 150 to 700 fold less potent competitors than LTC₄. These results provide evidence for specific, reversible, saturable, high affinity binding sites for [³H]-LTC₄ in human fetal lung membranes.     

Reorientation of Microfibrils and Microtubules at the Outer Epidermal Wall of Maize Coleoptiles During Auxin-Mediated Growth

Auxin-mediated elongation growth of isolated subapical coleoptile segments of maize (Zea mays L.) is controlled by the extensibility of the outer cell wall of the outer epidermis (Kutschera et al., 1987). Here we investigate the hypothesis that auxin controls the extensibility of this wall by changing the orientation of newly deposited microfibrils through a corresponding change in the orientation of cortical microtubules. On the basis of electron micrographs it is shown that cessation of growth after removal of the endogenous source of auxin is correlated with a relative increase of longitudinally orientated microfibrils and microtubules at the inner wall surface. Conversely, reinduction of growth by exogenous auxin is correlated with a relative increase of transversely orientated microfibrils and microtubules at the inner wall surface. These changes can be detected 30–60 min after the removal and addition of auxin, respectively. The functional significance of directional changes of newly desposited wall microfibrils for the control of elongation growth is discussed.     

多马胺能药物对鲇鱼促性腺激素（GtH）分泌活动的影响

以珠江流域鲇鱼（silurus asotus)为实验材料,研究了多巴胺（DA）能药物（DA及其D－2型受体拮抗物 ,DOM）对鲇鱼促性腺激素（GtH)释放的影响,结果表明,在性腺发育的各个时期,单独注射DOM（5ug/g)均不能显著提高鲇鱼血液基础GtH水平,当DOM与LHRH－A联合注射时能显著增强LHRH－A刺激GtH释放的作用;DA只能抑制GnRH诱导的GtH释放,对基础GtH释放无抑制作用,这种生殖内分泌调节方式与鲇形目的革胡子鲇（Clarias gariepinus)和大鳍Hu（Mystus macropterus)相似,而与鲤形目的鲁科（Cyrpindiae)鱼类不同。     

Gamma-glutamylcysteine protects ergothioneine-deficient Mycobacterium tuberculosis mutants against oxidative and nitrosative stress

Mycobacterium tuberculosis (M.tb.), the causative agent of tuberculosis (TB), cannot synthesize GSH, but synthesizes two major low molecular weight thiols namely mycothiol (MSH) and ergothioneine (ERG). Gamma-glutamylcysteine (GGC), an intermediate in GSH synthesis, has been implicated in the protection of lactic acid bacteria from oxidative stress in the absence of GSH. In mycobacteria, GGC is an intermediate in ERG biosynthesis, and its formation is catalysed by EgtA (GshA). GGC is subsequently used by EgtB in the formation of hercynine-sulphoxide-GGC. In this study, M.tb. mutants harbouring unmarked, in-frame deletions in each of the fives genes involved in ERG biosynthesis (egtA, egtB, egtC, egtD and egtE) or a marked deletion of the mshA gene (required for MSH biosynthesis) were generated. Liquid chromatography tandem mass spectrometry analyses (LC-MS) revealed that the production of GGC was elevated in the MSH-deficient and the ERG-deficient mutants. The ERG-deficient ΔegtB mutant which accumulated GGC was more resistant to oxidative and nitrosative stress than the ERG-deficient, GGC-deficient ΔegtA mutant. This implicates GGC in the detoxification of reactive oxygen and nitrogen species in M.tb.     

Interactions of an antitumor platinum compound with deoxyribonucleic acid, histones, L-amino acids, poly-L-amino acids, nucleosides and nucleotides

Interaction of cis-dichloro(dipyridine)platinum(II) (cis-PPC) with calf thymus DNA, calf thymus histone, l-amino acids, poly-l-amino acids, nucleosides, and nucleotides has been evaluated by equilibrium dialysis technics. At least a 28 % decrease in the association of cis-PPC with DNA occurs when the platinum compound is pre-incubated with l-amino acids. The greatest decrease in association is seen upon pre-incubation of the platinum compound with the free amino acids. Glut, Asp, Lys, Arg, and CySH, before the addition of a sack containing a solution of DNA. The low level of association between DNA and the amino acids tends to rule out competition between cis-PPC and amino acids for DNA association sites. cis-PPC was repelled from sacks containing positively charged poly-l-Lys, poly-l-Arg, and calf thymus histone; however, in the presence of poly-l-Glut and poly-l-Asp, cis-PPC associated with these negatively charged polymers to a considerable degree. Enhanced chloride dissociation from cis-PPC was observed in the presence of all of the amino acids and the nucleotides GMP, CMP, UMP, and TMP, but not in the presence of AMP or the nucleosides rG and dG. In the presence of calf thymus histone, the association of cis-PPC with calf thymus DNA was reduced by more than 50% at histone/DNA ratios of 0.8–1.0.These data suggest that cis-PPC or cis-Pt(II) may associate with electron-rich areas of not only nucleic acids and proteins but also with body pools of free nucleotides and amino acids. The presence of positively charged histones shielding DNA strands in vivo suggests that the most probable point of platinum-DNA association would be at de-repressed areas of DNA which are undergoing RNA synthesis. The aquated form of the platinum complex may also associate with acidic proteins which appear to be involved in the positive control of RNA synthesis and, as a result, this interaction may be of pharmacological significance.     

Tuning of electronic properties of one-dimensional cyano-bridged Cu-Ni, Cu-Pd, and Cu-Pt bimetallic assemblies by stereochemistry of ligands

Preparations, XPS and electronic spectroscopy, and magnetism of seven new one-dimensional cyano-bridged coordination polymers, chiral [Cu(RR-chxn)₂][Pd(CN)₄] · 2H₂O (1), [Cu(trans-chxn)₂][M(CN)₄] · 2H₂O (2, 4, and 6 for M = Pd, Ni, and Pt), and [Cu(cis-chxn)₂][M(CN)₄] · 2H₂O (3, 5, and 7 for M = Pd, Ni, and Pt) (RR-chxn = cyclohexane-(1R,2R)-diamine, trans-chxn = racemic trans-cyclohexane-(1,2)-diamine, and cis-chxn = racemic cis-cyclohexane-(1,2)-diamine) have been reported in view of tuning of their electronic properties by stereochemistry of chxn ligands and metal-substitution. Comparison of Cu 2p_1/2 and 2p_3/2 peaks of XPS and broad d-d bands around 18 000 cm⁻¹ of electronic spectra are described systematically for 1-7. Variable-temperature magnetic measurement shows that complexes 1-7 indicate weak antiferromagnetic interactions via cyano-bridges. Because of semi-coordination coupled with pseudo Jahn-Teller elongation and electrostatic interaction for 1, the axial Cu-N coordination bond distances of 2.330(7) and 3.092(8) Å are considerably longer than those of equatorial ones in the range from 2.016(6) to 2.030(6) Å. The former bond distances of 1 are intermediate values among the related Ni (2.324(6) and 3.120(8) Å) and Pt (2.34(1) and 3.09(1) Å) complexes.     

Biofortification of crops with seven mineral elements often lacking in human diets – iron, zinc, copper, calcium, magnesium, selenium and iodine

The diets of over two-thirds of the world's population lack one or more essential mineral elements. This can be remedied through dietary diversification, mineral supplementation, food fortification, or increasing the concentrations and/or bioavailability of mineral elements in produce (biofortification). This article reviews aspects of soil science, plant physiology and genetics underpinning crop biofortification strategies, as well as agronomic and genetic approaches currently taken to biofortify food crops with the mineral elements most commonly lacking in human diets: iron (Fe), zinc (Zn), copper (Cu), calcium (Ca), magnesium (Mg), iodine (I) and selenium (Se). Two complementary approaches have been successfully adopted to increase the concentrations of bioavailable mineral elements in food crops. First, agronomic approaches optimizing the application of mineral fertilizers and/or improving the solubilization and mobilization of mineral elements in the soil have been implemented. Secondly, crops have been developed with: increased abilities to acquire mineral elements and accumulate them in edible tissues; increased concentrations of 'promoter' substances, such as ascorbate, β-carotene and cysteine-rich polypeptides which stimulate the absorption of essential mineral elements by the gut; and reduced concentrations of 'antinutrients', such as oxalate, polyphenolics or phytate, which interfere with their absorption. These approaches are addressing mineral malnutrition in humans globally.     

八种脑-肠肽侧脑室内注射对大鼠基础胃酸分泌的影响

用乌拉坦麻醉大鼠作急性实验,采用连续灌流胃并收集流出液的方法,观察向侧脑室内注射微量脑-肠肽对大鼠基础胃酸分泌的影响。实验结果如下:(1)雨蛙肽、八肽胆囊收缩素、促甲状腺素释放激素及四肽胃泌素均使总酸排出量增加;(2)生长抑素、胰多肽、P 物质、胰高血糖素则使总酸排出量减少;(3)上述肽类用侧脑室注射的剂量作肌肉注射,除四肽胃泌素也产生明显的刺激胃酸分泌作用外,对胃酸分泌均无明显影响。以上结果提示,脑内的一些肽类可能以神经递质或调制物的方式,参与中枢对胃酸分泌的调节。