鲍鱼内脏酶解物可调节肠道菌群及短链脂肪酸缓解小鼠系统低度炎症

为探究鲍鱼内脏酶解物对辣椒素诱导的系统低度炎症模型小鼠炎性因子、肠道菌群及短链脂肪酸的影响,将30只雄性小鼠随机分为6组：空白对照组、辣椒素致炎模型组、鱼油对照组、鲍鱼内脏酶解物低、中、高剂量组(0.30、0.60、1.20 g/(kg·d)),干预7 d后,ELISA法检测小鼠血清中肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)、白细胞介素-10(IL-10),鲎试剂法测定小鼠血清中细菌脂多糖(LPS)的含量,16S rRNA基因高通量测序和生物信息学方法考察小鼠肠道菌群的结构组成,GC-MS法测定小鼠粪便中短链脂肪酸的含量。结果显示,辣椒素模型组小鼠血清中TNF-α、IL-6和LPS含量显著升高,肠道菌群OTUs数显著降低,菌群各门、属水平比例存在显著变化,其中寡养单胞菌属(Stenotrophomonas)和棒状杆菌属(Corynebactrium)等有害相对丰度显著增加,粪便中的乙酸、丙酸以及总短链脂肪酸含量显著降低,异戊酸含量显著升高,而经鲍鱼内脏酶解物干预后,小鼠血清中IL-1β、IL-6和LPS含量显著降低,肠道中乳杆菌属(La...     

地锦粗提物对脾虚小鼠脏器指数和抗氧化能力的影响

目的探讨地锦粗提物对脾虚小鼠脏器指数和抗氧化能力的影响,为防治脾虚提供参考。方法 30只昆明小鼠随机分成3组,每组10只,即对照组、脾虚组和地锦组。脾虚组和地锦组采用泻下加劳倦方法,灌服大承气汤30 g/(kg.d),并负重游泳,对照组灌服生理盐水30 g/(kg.d),不游泳,持续60 d,然后灌胃60 d,地锦组灌胃地锦水醇浸出液30 g/(kg.d),脾虚组和对照组给予相当剂量的生理盐水。实验结束后取心、肝、脾、肺、肾,称重并计算脏器指数,测血浆过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)活力,测心、肝、脾、肺、肾中超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量。结果脾虚组心指数和肺指数极显著增加,左肾指数显著增加,地锦组心指数显著增加。地锦组的血浆CAT和GSH-Px活力显著高于脾虚组,地锦组肝和脾中的SOD活力显著高于脾虚组,地锦组脾、肺MDA含量显著低于脾虚组。结论地锦粗提物可降低脾虚小鼠的脏器指数,并可提高脾虚小鼠抗氧化能力。     

合生元益生菌冲剂对小鼠肠道菌群调节作用的研究

目的 研究合生无益生菌冲剂对小鼠肠道菌群的调节作用.方法 将小鼠分为阴性对照组、合生元益生菌冲剂组.阴性对照组灌服蒸馏水14 d,合生元益生菌冲剂组灌服1 g/kg·d剂量的台生元益生菌冲剂14 d,检测实验前后肠道菌群数量.结果 灌服后小鼠肠道菌群与灌服前比较,,双歧杆菌数量有显著性增加（P＜0.05）,肠杆菌、肠球菌、乳杆菌和产气荚膜梭菌数量有无显著性变化（P＞0.05）.结论 合生元益生菌冲剂对小鼠肠道菌群具有一定的调节作用.     

16S rDNA实时荧光定量PCR检测大蒜提取物对小鼠肠道菌群的调节作用

目的 探究蒜氨酸、大蒜辣素、大蒜粉对小鼠肠道菌群的调节作用。方法 将SPF级C57BL/6J小鼠分为空白对照组、蒜氨酸组、大蒜辣素组和大蒜粉组,每组10只。空白对照组小鼠灌服蒸馏水30 d,蒜氨酸组、大蒜辣素组、大蒜粉组小鼠灌服不同浓度的受试物溶液30 d,采用16S rDNA实时荧光定量PCR检测实验前后小鼠粪便样本中乳杆菌、双歧杆菌、肠杆菌、肠球菌、产气荚膜梭菌水平变化。结果 给药30 d后,与空白对照组相比、实验前后自身对比,蒜氨酸组、大蒜辣素组、大蒜粉组小鼠的肠杆菌、肠球菌水平无明显变化;乳杆菌、双歧杆菌水平显著增加;产气荚膜梭菌水平显著降低。结论 蒜氨酸、大蒜辣素、大蒜粉对肠道菌群具有有益的调节作用,是一种良好的天然有益于肠道菌群的食品。     

中草药对小鼠肠道菌群影响的实验研究

目的研究党参、茯苓、白术、白芍和陈皮五味中药制成的复方合剂对肠道菌群调节作用。方法将小鼠分为正常对照组、低剂量组、中剂量组和高剂量组。对照组灌服蒸馏水14 d,低剂量组、中剂量组和高剂量组灌服不同剂量的复方合剂14 d,检测实验前后肠道菌群数量。结果灌服后小鼠肠道菌群与灌服前比较,乳杆菌、双歧杆菌数量明显增加,肠球菌数量明显减少,肠杆菌数量差异无统计学意义。结论党参、茯苓、白术、白芍和陈皮五味中药制成的复方合剂对小鼠肠道菌群具有一定的调节作用。     

蛴螬肽提取物对铅致小鼠肾中毒的解毒保护作用机制研究

目的 本实验通过构建醋酸铅致小鼠肾中毒模型,探讨蛴螬肽提取物对小鼠的解毒保护作用机制,为机体铅性肾病的防治提供试验依据。方法 随机取小鼠分为对照组、模型组、阳性药组以及不同剂量蛴螬肽组(80、160、320 mg/kg),除对照组外所有组小鼠隔天腹腔注射醋酸铅20 mg/kg,连续15 d。此时对照组和模型组小鼠同时灌服生理盐水而阳性药组小鼠灌服二巯基丁二酸(DMSA 70 mg/kg)混悬液,蛴螬肽组小鼠灌服不同剂量蛴螬肽提取物,每天1次连续15 d,采用HE染色显微镜观察肾组织状态;检测肾功能指标(BUN、Cr)和肾组织中抗氧化酶水平(SOD、GSH-Px)及过氧化物(MDA)含量;RT-PCR、Western Blot技术检测分析Ⅱ相解毒酶(NQO1)、抗氧化酶(HO-1)和信号分子(Nrf2)基因和蛋白表达水平。结果 蛴螬肽组与模型组小鼠相比,体重增加但低于对照组,肾组织形态显著改善,血清中BUN、Cr水平显著降低(P<0.05),肾组织中抗氧化酶(SOD、GSH-Px)水平显著提高(P<0.05),MDA含量显著减少,Ⅱ相解毒酶基因(NQO1)、抗氧化酶(HO-1...     

中药地黄饮子对小鼠抗体激发水平的影响

目的:探讨地黄饮子对小鼠抗体激发水平的影响。方法:将40只经卵核蛋白免疫过的小鼠随机分A、B两组,分别灌服地黄饮子和葡萄糖,1次/d,每次0.5mL只,连续7d后,加强免疫,再经7d,用ELISA法检测血清中相应抗体生成水平。结果:与葡萄糖组比较,地黄饮子组小鼠抗体水平升高,差异有显著性意义(P<0.05)。结论:地黄饮子有可能促进小鼠抗体激发水平和免疫水平的提高。     

中药地黄饮子对小鼠抗体激发水平的影响

目的：探讨地黄饮子对小鼠抗体激发水平的影响。方法：将40只经卵核蛋白免疫过的小鼠随机分A、B两组,分别灌服地黄饮子和葡萄糖,1次/d,每次0.5mL只,连续7d后,加强免疫,再经7d,用ELISA法检测血清中相应抗体生成水平。结果：与葡萄糖组比较,地黄饮子组小鼠抗体水平升高,差异有显著性意义（P〈0.05）。结论：地黄饮子有可能促进小鼠抗体激发水平和免疫水平的提高。     

大蒜素对小鼠脾细胞雌激素和雄激素受体影响的实验研究

本研究旨在探讨大蒜素对小鼠脾细胞雌激素和雄激素受体的影响。将健康ICR清洁小鼠,按性别随机分成三组实验组和三组对照组。实验组分别连续灌服大蒜素14、21和28 d,对照组同期分别灌服等量生理盐水。采用RT-PCR法检测雌性各组小鼠脾细胞雌激素受体(ERα和ERβ)的mRNA表达水平和雄性各组小鼠脾细胞雄激素受体(AR)的mRNA水平。实验结果显示,雌性小鼠连续灌服大蒜素第14和21 d时实验组ERαmRNA表达水平明显高于对照组(P0.05),第14 d时ERβmRNA表达水平明显高于对照组(P0.05)。雄性小鼠连续灌服大蒜素第14、21和28 d时实验组AR mRNA表达水平均明显高于对照组(P0.05)。综上提示大蒜素可增强小鼠脾细胞雌激素受体(ERα和ERβ)和雄激素受体(AR)mRNA的表达水平。     

谷氨酰胺对溃疡性结肠炎小鼠结肠损伤的影响

目的：探讨谷氨酰胺（Gln）对溃疡性结肠炎小鼠结肠黏膜损伤的影响。方法：将64只35日龄中国昆明鼠随机分为4组（n=16）：即Ⅰ组（空白对照组）、Ⅱ组（模型组）、Ⅲ组（Gln低剂量组）、Ⅳ组（Gin高剂量组）,Ⅱ、Ⅲ、Ⅳ组采用乙酸灌肠法人工复制小鼠溃疡性结肠炎模型,模型复制成功后Ⅰ、Ⅱ组均给予一定量的生理盐水灌服,Ⅲ、Ⅳ组分别灌服与生理盐水量相等的低（2mmol·kg^-1 bw）、高（4mmol·kg^-1 bw）两种浓度的Gln溶液,连续灌服7d后将小鼠处死。观察结肠病理组织学变化,检测血清内毒素含量,结肠组织的抗氧化水平、髓过氧化物酶（Ⅶ的）活性。结果：Gln减轻了由结肠炎造成的结肠黏膜的病理损伤,一定程度上缓解了结肠炎时血清内毒素急剧升高、结肠抗氧化水平降低及髓过氧化物酶活性升高等现象。结论：Gln对溃疡性结肠炎所致小鼠结肠损伤具有一定的修复作用。     

壳聚糖酶的克隆表达与壳寡糖的制备分析

目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。     

国内外蝗害治理技术现状与展望

本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...     

Kinetics and thermodynamics of peroxidase- and laccase-catalyzed oxidation of N-substituted phenothiazines and phenoxazines

N -substituted phenothiazines (PTs) and phenoxazines (POs) catalyzed by fungal Coprinus cinereus peroxidase and Polyporus pinsitus laccase were investigated at pH 4–10. In the case of peroxidase, an apparent bimolecular rate constant (expressed as k _cat/K _m) varied from 1 ×10⁷M⁻¹s⁻¹to 2.6×10⁸M⁻¹s⁻¹ at pH 7.0. The constants for PO oxidation were higher in comparison to PT. pH dependence revealed two or three ionizable groups with pK _a values of 4.9–5.7 and 7.7–9.7 that significantly affected the activity of peroxidase. Single-turnover experiments showed that the limiting step of PT oxidation was reduction of compound II and second-order rate constants were obtained which were consistent with the constants at steady-state conditions. Laccase-catalyzed PT and PO oxidation rates were lower; apparent bimolecular rate constants varied from 1.8×10⁵M⁻¹s⁻¹ to 2.0×10⁷M⁻¹s⁻¹ at pH 5.3. PO constants were higher in comparison to PT, as was the case with peroxidase. The dependence of the apparent bimolecular constants of compound II or copper type 1 reduction, in the case of peroxidase or laccase, respectively, was analyzed in the framework of the Marcus outer-sphere electron-transfer theory. Peroxidase-catalyzed reactions with PT, as well as PO, fitted the same hyperbolic dependence with a maximal oxidation rate of 1.6×10⁸M⁻¹s⁻¹ and a reorganization energy of 0.30 eV. The respective parameters for laccase were 5.0×10⁷M⁻¹s⁻¹ and 0.29 eV. Received: 20 September 1999 / Accepted: 24 February 2000     

Coiled-coil nanomechanics and uncoiling and unfolding of the superhelix and alpha-helices of myosin

The nanomechanical properties of the coiled-coils of myosin are fundamentally important in understanding muscle assembly and contraction. Force spectra of single molecules of double-headed myosin, single-headed myosin, and coiled-coil tail fragments were acquired with an atomic force microscope and displayed characteristic triphasic force-distance responses to stretch: a rise phase (R) and a plateau phase (P) and an exponential phase (E). The R and P phases arise mainly from the stretching of the coiled-coils, with the hinge region being the main contributor to the rise phase at low force. Only the E phase was analyzable by the worm-like chain model of polymer elasticity. Restrained molecular mechanics simulations on an existing x-ray structure of scallop S2 yielded force spectra with either two or three phases, depending on the mode of stretch. It revealed that coiled-coil chains separate completely near the end of the P phase and the stretching of the unfolded chains gives rise to the E phase. Extensive conformational searching yielded a P phase force near 40 pN that agreed well with the experimental value. We suggest that the flexible and elastic S2 region, particularly the hinge region, may undergo force-induced unfolding and extend reversibly during actomyosin powerstroke.     

Synthesis of hapten and conjugates of coumestrol and development of immunoassay

3-O-Carboxymethylcoumestrol was prepared as the hapten for immunoassay by a partial alkylation of coumestrol with ethyl chloroacetate in acetone alkalized with potassium carbonate. 3-O-Ethoxycarbonylmethylcoumestrol was separated by column chromatography and finally was hydrolyzed with formic acid. 1H and 13C NMR data (APT, COSY, HMQC, and HMBC) revealed that the reaction was regioselective, as 3-O-ethoxycarboxymethylcoumestrol was the only monosubstituted derivative. The hapten was then conjugated to bovine serum albumin and used for immunization of rabbits. A radioimmunoassay (RIA) system was established based on the polyclonal antiserum and a 125I-labeled hapten-tyrosine methyl ester conjugate as the radioligand. Parameters of the RIA: sensitivity: 12 pg per tube, 50% intercept: 140 pg per tube, working range: 20-4000 pg per tube. The cross-reactivity of a panel isoflavonoid and lignan phytoestrogens was either negligible (e.g. formononetin 0.07%; biochanin A 0.06%) or not detectable at all. The major immunoreactive peak in HPLC fractions from an alfalfa extract had the same retention time as coumestrol standard and represented 94.8% of the signal. The remaining 5.2% of immunoreactivity was distributed between five minor peaks. We conclude that after the validation for particular matrices, the method will be a useful tool for analysis of coumestrol, especially in low volume and low concentration samples.     

白术同源四倍体的诱导和鉴定及其与二倍体过氧化物酶的比较

以白术（Atractylodes macrooephala Koidz.）二倍体组培苗为材料,对其四倍体诱导方法进行研究,共获得45个白术同源四倍体株系,为优良株系的选育提供了材料。此外,还分析比较了其中8个白术四倍体株系与二倍体的过氧化物酶同工酶（POD）的酶谱差异,发现四倍体各株系过氧化物酶同工酶谱比二倍体的均多了Rf0.310的谱带,且总过氧化物酶比活力也发生了很大改变,对探讨白术四倍体优良株系的生理生化机理具有一定的参考价值。     

Effect of soil salinity and water stresses on growth and content of nitrogen,chloride and phosphate of wheat and triticale

Summary Three wheats and one triticale were grown, up to flowering stage, in pots on calcareous soil adjusted to a range of salinities (S₁=3.5, S₂=6, S₃=8.5, and S₄=11 mmhos/cm, 20°C, soilpaste extract) by adding solution consisting of 3∶2∶1 of Na-, Ca- and Mg chlorides in chemical equivalent amounts. Moisture in the pots was kept at 100% (W₁), 40% (W₂) and 20% (W₃) of the available water. The vegetative growth, nitrogen and phosphate were affected by S and W treatments, chloride was affected only by S. The interaction S×W affected only dry weight. Varietal effect was observed between wheat as a group and triticale. Multiple quadratic regression equations of these properties on salinity and water revealed that the higher the available water the wider the range of tolerable salinity. Triticale was relatively more tolerant to water stress. Salinity increases Cl and decreases N, whereas water stress enhances N accumulation to a certain extent. However, in triticale at S₃ and S₄ the effect of water stress on N was overshadowed by the excessive salinity. This did not occur for the wheat (Florence). P trends were described. R² for P was low (0.7435–0.3603) which made interpretations rather difficult.     

放牧对牧草光合作用、呼吸作用和氮、碳吸收与转运的影响

研究放牧对草地植物生理活动的影响,对于揭示草地放牧演替的生理机制有重要意义.大量研究表明,家畜放牧对牧草光合作用、呼吸作用以及C和N吸收与转运的影响,可以分为生理伤害和生理恢复2个阶段.放牧通过改变草地冠层结构影响牧草光合作用,净光合作用速率短期内迅速下降,随着叶面积指数增加又逐渐上升,呼吸作用有相似的变化趋势.牧草放牧后再生长所需的C和N最初主要来自根系和留茬中的贮藏物质,此后随着牧草生长恢复逐渐由同化作用供给,C代谢与土壤N水平负相关.放牧后牧草生理活动变化与牧草遗传特性、种间竞争、家畜放牧特征、非生物环境等因素密切相关.