雌激素对荷斯坦奶牛输卵管上皮细胞中前列腺素E2受体EP2和EP4 mRNA表达的影响

本实验旨在探讨奶牛输卵管上皮细胞中是否存在前列腺素E2受体EP2和EP4,且该受体mRNA表达是否受雌激素(E2)的调控。将前列腺素类化合物PGE2和受体选择性激动剂(butaprost)按10-9mol/L-10-5mol/L的浓度分别作用于体外培养的奶牛输卵管上皮细胞,应用Elisa方法检测细胞中第二信使cAMP量的变化。然后,将E2作用于体外培养的奶牛输卵管上皮细胞,应用real time RT-PCR技术检测EP2和EP4受体mRNA表达量的变化。Elisa实验结果显示,前列腺素类化合物PGE2和受体选择性激动剂(butaprost)可引起奶牛输卵管上皮中cAMP量的变化,且cAMP量具有对PGE2和butaprost浓度依存性的变化规律,表明奶牛输卵管上皮细胞中存在前列腺素受体EP2和EP4。Real time RT-PCR实验结果表明,奶牛输卵管上皮细胞中存在前列腺素受体EP2和EP4,且E2对EP2和EP4受体mRNA的表达具有调控作用,低浓度(10-12mol/L)可提高该受体mRNA的表达量。     

除虫脲在人工胃/肠液和肠道菌群及生物样品中的稳定性研究

为了考察除虫脲(DFB)在人工胃/肠液和肠道菌群及生物样品中的稳定性,为合理开发DFB口服制剂提供试验依据.采用高效液相色谱法(HPLC),分别将DFB与空白人工胃液(pH为1.3,不含酶)、空白人工肠液(pH为6.8,不含酶)、人工胃液(pH为1.3,含胃蛋白酶)、人工肠液(pH为6.8,含胰蛋白酶)、SD大鼠(雄性...     

Pregnancy interception with a combination of prostaglandins: studies in monkeys

Treatment with combinations of synthetic prostaglandins, one with an ovarian site of action and one with a uterine site of action, terminated pregnancy in all rhesus monkeys given the injection on day 28 of fertile menstrual cycles. Single prostaglandins, even at higher doses, interrupted pregnancy in only one-third of the monkeys. The most effective treatment, 5-oxa-17-phenyl-18,19,20-trinor prostaglandin F1 alpha methyl ester plus 9-deoxo-16,16-dimethyl-9-methylene prostaglandin E2, promptly intercepted early pregnancy after a single administration and without side effects.     

Reinitiation of growth in senescent mouse mammary epithelium in response to cholera toxin

Several lines of mouse mammary tissue that had been serially transplanted until mitotic senescence was reached were exposed in vivo to plastic implants that slowly released cholera toxin. Gland tissue surrounding the implants displayed new end buds, indicating reinitiation of growth and morphogenesis. The ability of cholera toxin, which elevates intracellular adenosine 3',5'-monophosphate, to temporarily reverse the senescent phenotype suggests that this mitotic dysfunction results not from generalized cellular deterioration but from specific changes in cell regulation.     

Prostaglandins: localization in subcellular particles of rat cerebral cortex

Homogenates of rat cerebral cortex contain material corresponding to prostaglandins E(1), E(2), F(1)alpha, and F(2)alpha which are concentrated mainly in the light microsomal and mitochondrial fractions. Only the former fraction exhibits significant ability to synthesize prostaglandins E(1) and F(1)alpha from bis-homo-gamma-linolenic acid. After subfractionation of the crude mitochondrial fraction, prostaglandin E and F material is found mainly in the cholinergic and noncholinergic nerve endings. We conclude that the nerve endings are a storage site, whereas the light microsomes are the site of synthesis.     

Oxytocin receptors and human parturition: a dual role for oxytocin in the initiation of labor

The concentration of oxytocin receptors increased in the myometrium of pregnant women and reached maximum levels in early labor. Concentrations of oxytocin receptors were also high in the decidua and reached a maximum at parturition. In vitro, prostaglandin production by the decidua, but not by the myometrium, was increased by the addition of oxytocin. Oxytocin may therefore stimulate uterine contractions by acting both directly on the myometrium and indirectly on decidual prostaglandin production. Oxytocin receptors are probably crucial for the onset of human labor, and the stimulus for the increase in uterine prostaglandins may be oxytocin originating from the fetus.     

鱼用口服疫苗免疫佐剂研究进展

免疫佐剂是一种先于或与抗原同时使用,能够增强机体的非特异性免疫能力及相应抗原的免疫原性,但其本身不具备抗原特性的物质.文章对鱼用口服疫苗免疫佐剂的作用机理以及霍乱毒素(CT)、大肠杆菌不耐热肠毒素(LT)、细胞因子等几种主要鱼用口服疫苗免疫佐剂的应用情况进行综述,发现鱼用口服疫苗免疫佐剂的研究应用过程中仍存在作用机理研究相对滞后、忽略肠道黏膜免疫机理特殊性、使用成本过高、安全性等问题,建议今后加强对鱼类肠道黏膜免疫机理以及口服疫苗免疫佐剂作用机理的研究,优化口服疫苗免疫佐剂的免疫剂量和程序,降低生产成本,研发出更为广泛、廉价的口服疫苗免疫佐剂,提高其安全性等,以促进水产养殖业的健康发展.     

实时荧光定量PCR检测感染小鼠肠道内容物的LT肠毒素基因

构建LT-PMD19质粒标准品,进行SYBR Green荧光定量PCR检测产肠毒素大肠杆菌(ETEC)LT基因,以确定该方法的特异性和灵敏度,绘制标准曲线;通过腹腔注射0.2mL ETEC菌液建立小鼠腹泻模型,分别于感染后4h、15h、2d、7d和14d各处死2只,通过建立的荧光定量PCR方法对小肠液中的ETEC的LT基因进行定量检测。研究结果显示,用建立的荧光定量PCR检测LT基因无非特异性扩增,标准曲线呈良好的线性关系(R2=0.999),标准品的熔解曲线均呈单峰,灵敏度为8.18×103拷贝数/μL;小鼠感染4h后LT毒素含量最高,剖检可见小肠肿大,充满黄绿色的内容物,感染后7d、14d均未检测出LT毒素,肠道未见明显病变,表明LT肠毒素在肠道内的生成规律与肠道病变损伤呈正相关。     

Prostaglandins stimulate thyroid function in pregnant women

Intravaginal or intravenous administration of prostaglandin F(2alpha) to pregnant women produced significant elevations of plasma triiodothyronine and thyroxine concentrations, but no rise of thyrotropin. These observations are consistent with those of previous in vitro studies indicating that prostaglandins can act directly on the thyroid gland to stimulate thyroid hormone synthesis or release, or both.     

嗜线虫致病杆菌杀虫毒素对棉铃虫的中肠组织病理学研究

 嗜线虫致病杆菌HB310菌株与小卷蛾斯氏线虫HB310共生，对多种昆虫均具有较高生物活性。本实验通过盐析和非变性凝胶电泳等方法从嗜线虫致病杆菌HB310菌株的细胞内分离纯化出具胃毒活性的蛋白毒素Ⅱ。经毒素Ⅱ处理的棉铃虫幼虫，中肠组织的病理学变化类似于发光杆菌Tca毒素和Btδ-内毒素。棉铃虫4龄幼虫口服毒素Ⅱ 6 h后中肠组织开始发生变化：首先围食膜前端破碎，中肠柱状细胞伸长；随着时间推移，12 h后整个围食膜被破坏消失，中肠组织病变加重，肠壁细胞排列疏松混乱；随着毒素作用的逐渐减弱，处理72 h后棉铃虫中肠围食膜又重新出现。毒素Ⅱ离体处理棉铃虫围食膜，同样可以导致围食膜破碎。     

Immune response to cholera toxin epitope inserted in Salmonella flagellin

Bacterial flagella are potent immunogens and aromatic-dependent (aro) Salmonella as live vaccines evoke humoral and cellular immune responses. Such strains expressing epitopes of protective antigens as inserts in flagellin would provide a novel way to vaccinate against diseases caused by unrelated pathogens. A synthetic oligonucleotide specifying an epitope of cholera toxin subunit B was inserted in a Salmonella flagellin gene. The chimeric flagellin functioned normally and the epitope was expressed at the flagellar surface. Parenteral administration to mice of an aro A flagellin-negative strain of S. dublin expressing the chimeric flagellin gene evoked antibody to cholera toxin.     

Prostaglandins E1 and E2 antagonize norepinephrine effects on cerebellar purkinje cells: microelectrophoretic study

In microelectrophoretic experiments, prostaglandins E(1) and E(2) antagonize the reduction in discharge rate of cerebellar Purkinje cells produced by norepinephrine. Slowing of discharge evoked by 3',5'-adenosine monophosphate or gamma aminobutyric acid is not antagonized. These data provide the first indication that endogenous prostaglandins may physiologically function to modulate central noradrenergic junctions.     

Diarrhea toxin obtained from a waterbloom-producing species, Microcystis aeruginosA Kützing

A diarrhea-producing toxin from a blue-green alga, Microcystis aeruginosa Kützing, was obtained from standing laboratory cultures. The non-dialyzable fraction of the lysate from whole cells produced fluid accumulation in the ligated small intestinal loops in guinea pigs.     

Regulation of muscle differentiation: stimulation of myoblast fusion in vitro by catecholamines

Epinephrine and isoproterenol provoke primary chick myoblasts to initiate precocious cell fusion. Both the rise in intracellular adenosine 3' ,5-monophosphate (cyclic AMP) and cell fusion generated by these effectors are prevented by propranolol, which is a specific blocker of the beta-adrenergic receptor. Propranolol has no effect either on the precocious cell fusion provoked by prostaglandin E or on cell fusion in control cultures. The results support the idea that a rise in cyclic AMP is the critical intracellular change responsible for initiating events that culminate in myoblast differentiation 4 to 5 hours later. They also indicate that the culminate in myoblast differentiation 4 to 5 hours later. They also indicate that the hormone responsible for the positive regulation of myoblast differentiation in vitro is not acting through the beta-adrenergic receptor.     

Separation of type 2 toxins of Vibrio cholerae

Choleragenic toxin was separated from vascular permeability factor by ion-exchange chromatography of supernatants of dialyzed peptone cultures of Vibrio cholerae. The choleragenic toxin eluted from columns of QAE-Sephadex with low-ionicity systems is free of permeability factor activity. Further elution of these columns with 0.5M NaCl removes both the permeability factor and residual choleragenic toxin. When this latter material is chromatographed on columns of carboxymethyl-Sephadex, the permeability factor toxin is eluted by 0.02M phosphate buffer and is free of choleragenic activity. Therefore, choleragenic and permeability factor activities of the type 2 cholera toxins are different and can be separated by these procedures.     

双歧杆菌对病原菌粘附肉鸡肠粘液的影响

研究两歧双歧杆菌、禽大肠杆菌O78、大肠杆菌ATCC25922、鸡白痢沙门氏菌和鼠伤寒沙门氏菌与肉鸡不同肠段粘液糖蛋白的粘附性能，探讨两歧双歧杆菌对四种病原菌的粘附排斥作用。结果表明，在不同的肠道部位，两歧双歧杆菌、鸡白痢沙门氏菌和鼠伤寒沙门氏菌与肠粘液糖蛋白的粘附能力不同，而禽大肠杆菌O78、大肠杆菌ATCC25922在各肠段粘液上的粘附性能相近；在相同的肠道部位，所试菌与肠粘液糖蛋白的粘附能力有差异，其中两歧双歧杆菌的粘附作用最强；肠粘液糖蛋白经两歧双歧杆菌处理后，禽大肠杆菌O78、大肠杆菌ATCC25922和鸡白痢沙门氏菌的粘附作用受到抑制，而鼠伤寒沙门氏菌在十二指肠、空肠粘液上的粘附率未见下降。     

Selective reduction of forskolin-stimulated cyclic AMP accumulation by inhibitors of protein synthesis

Inhibiting protein synthesis by incubating C6-2B rat astrocytoma cells with cycloheximide or emetine for periods up to 24 hours caused a progressive decrease in the accumulation of adenosine 3',5'-monophosphate (cyclic AMP) when the cells were challenged for 30 minutes with 100 microM forskolin. In contrast, cholera toxin-stimulated (6 nM, 3 hours) cyclic AMP accumulation was not diminished in cycloheximide-treated cells, and cyclic AMP was only minimally diminished in response to a 30-minute challenge with 10 microM (-)-isoproterenol. These experiments suggest the presence of a previously unrecognized cyclase component, which is essential for forskolin-stimulated cyclic AMP accumulation and has a shorter half-life than the beta-adrenergic receptor, the guanine nucleotide regulatory proteins, or the cyclase catalytic component.     

Host-Specific Phytotoxic Polysaccharide from Apple Tissue Infected by Erwinia amylovora

A toxin isolated from apple fruit tissue infected by Erwinia amylovora is 98 percent galactose in polymeric form, 0.375 percent protein, and has an average molecular weight of approximately 165,000. Young shoots of rosaceous, but not nonrosaceous, species wilt in a manner characteristic of the disease when placed in toxin solutions with concentrations as low as 10 micrograms per milliliter. Varieties of apple and pear susceptible to Erwinia amylovora wilt in 1 to 3 hours, whereas resistant varieties display symptoms 12 to 24 hours after treatment.     

Pulmonary alveolar hypoxia: release of prostaglandins and other humoral mediators

Hypoxic ventilation of isolated perfused cat lungs caused the frequent appearance in pulmonary perfusates of biologically active substances, which included prostaglandins or prostaglandin-like compounds. In anesthetized cats, inhibition of prostaglandin biosynthesis with infusions of aspirin (more than 50 milligrams per kilogram) reduced the pulmonary vasoconstrictor and bronchoconstrictor responses to hypoxic breathing.