棘胸蛙（Quasipaa spinosa）对重复急性冷暴露的生理应激与适应耐受

为探讨棘胸蛙(Quasipaa spinosa)这一溪源性两栖类对环境温度极端变化做出的生理响应与适应机制,测定了该物种在反复遭受急性冷暴露(4℃,12 h)过程中其非特异性免疫反应、氧化还原状态以及热休克蛋白70(Hsp70)mRNA表达的变化,结果发现:棘胸蛙在初次冷暴露过程中外周血细胞吞噬活性(第4小时和第12小时;P0.05)、脾巨噬细胞呼吸爆发强度(第4小时和第12小时;P0.05)以及胃溶菌酶活力受到显著抑制(第12小时;P0.05);当蛙返回到22℃环境12 h后3种免疫指标均恢复到初始和对照组水平(P0.05)。经过连续7 d冷暴露后,除溶菌酶外,血细胞吞噬活性和脾巨噬细胞呼吸爆发强度均能恢复到初始和对照组水平(P0.05)。另外,冷暴露增加了肝脏和肾脏内丙二醛(MDA)的含量,但肾脏内MDA含量升高的幅度要明显大于肝脏;肝脏SOD活力和GSH含量也表现出急性和适应性升高,而肾脏仅SOD活力有所升高,暗示在低温胁迫状态下棘胸蛙肝脏氧自由基清除能力要强于肾脏。HSP70作为应激保护蛋白,当机体遭受冷暴露后肝脏Hsp70 mRNA表达量始终未呈现出应激性升高,反而受到显著抑制(P0.05)。综上所述,棘胸蛙在经历多次急性冷胁迫后体内部分非特异性免疫功能以及肝脏氧化防御系统可以产生不同程度的适应性改变。     

松子壳多糖对小鼠主要免疫细胞功能的影响

目的探讨松子壳多糖（pine nut shell polysaccharide,PSP）对小鼠主要免疫细胞的影响。方法应用MTT法测定PSP对小鼠脾淋巴细胞的毒性和对ConA或LPS诱生小鼠脾T、B淋巴细胞的转化,用中性红吞噬试验测定腹腔巨噬细胞的吞噬功能,应用乳酸脱氢酶释放法测定NK细胞的杀伤活性。结果 PSP对脾细胞毒性很低,各种浓度对小鼠脾淋巴细胞的增殖均有较强的促进作用（P〈0.01）;PSP在浓度50～300μg/mL时,明显促进T淋巴细胞的转化（P〈0.01）,但是当浓度达到300μg/mL时表现出一定的抑制作用（P〉0.05）;PSP在25～200μg/mL时显著促进了小鼠脾B淋巴细胞的转化（P〈0.05）,但是当浓度达到300μg/mL时,抑制作用极显著（P〈0.01）;不同浓度均可以增强小鼠腹腔巨噬细胞吞噬中性红的能力及其代谢功能,当浓度在100μg/mL时能显著的促进巨噬细胞吞噬中性红的能力（P〈0.01）;PSP在浓度100～300μg/mL时,能极显著的促进NK细胞对Yac-1的杀伤作用（P〈0.01）,当浓度达到400μg/mL,对NK细胞杀伤性的促进作用开始减弱。结论 PSP对小鼠脾淋巴细胞的毒性较低,能增强免疫细胞活性,有望成为新一代免疫调节剂。     

小麦肽对受环磷酰胺免疫抑制小鼠的免疫调节及抗氧化功能

本研究旨在分析小麦蛋白活性肽对免疫抑制小鼠免疫功能和抗氧化功能的调节作用。小鼠灌胃小麦肽10d,第8天用环磷酰胺诱导免疫抑制,测定血清溶血素、抗体生成细胞含量、脾细胞增殖、体外腹腔巨噬细胞吞噬能力、肝脏抗氧化酶活性和丙二醛(MDA)含量以及血清清除DPPH和·OH的能力。实验结果表明,环磷酰胺处理显著的降低了小鼠血清中抗SRBC抗体(溶血素HC50)水平和腹腔巨噬细胞的吞噬能力;同时伴随着肝脏超氧化物歧化酶活性(SOD)、过氧化氢酶活力(CAT)、总抗氧化能力(T-AOC)的降低和MDA含量的提高。给小鼠灌胃小麦肽可以恢复HC50和脾细胞增殖,显著提高抗体生成细胞含量和腹腔巨噬细胞吞噬能力;此外,小麦肽增强了小鼠血清清除DPPH和清除·OH的能力。以上结果表明,小麦肽可以调节应激状态引起的机体抗氧化体系紊乱及免疫功能的降低。这可能与小麦肽缓冲自由基生成、激活腹腔巨噬细胞和脾淋巴细胞活性有关。     

在低氧损伤中牛磺酸对视网膜神经节转化细胞RGC-5抗氧化作用的研究

目的:观察低氧(Hypoxia,Hyp)对大鼠视网膜神经节转化细胞(retina ganglion cell-5,RGC-5)氧化应激损伤的影响及牛磺酸(Taurine,Tau)的防护效应.方法:将RGC-5置于低氧条件(5%O2,5%CO2,90%N2),加入不同浓度的牛磺酸(0.05mM、0.1mM、0.5mM、1mM)预处理后培养12h,24h和48h,使用MTT法检测细胞活力,并通过对NO、GSH、MDA等指标的检测,观察牛磺酸对RGC-5的保护效应.结果:低氧处理后RGC-5细胞活力明显降低(P＜0.05),牛磺酸处理组细胞活力明显高于低氧组,其中0.1mM牛磺酸组作用最为显著(P＜0.05);低氧组与常氧组比较,RGC-5的NO、GSH含量明显降低(P＜0.05),而MDA含量显著升高(P＜0.05);牛磺酸处理组与低氧组比较,RGC-5细胞GSH,NO的含量显著升高(P＜0.05),而MDA的含量显著降低(P＜0.05).结论:牛磺酸能有效增强低氧损伤中RGC-5细胞的活力,其机制可能与牛磺酸可以提高其抗氧化能力有关.     

Cd2+-B[α]P复合污染对菲律宾蛤仔急性毒性和解毒代谢酶活力的影响

文章研究了Cd2+-B[α]P复合污染对菲律宾蛤仔的急性毒性和鳃丝、消化盲囊解毒代谢酶活力的影响。结果表明:Cd2+对菲律宾蛤仔48、72、96h LC50分别为50.41、24.12、14.68 mg/L,Cd2+-B[α]P对菲律宾蛤仔的联合急性毒性48—96h表现为协同作用。Cd2+、B[α]P单一与复合污染对菲律宾蛤仔鳃丝、消化盲囊谷胱甘肽(GSH)含量、谷胱甘肽硫转移酶(GST)和超氧化物歧化酶(SOD)活力的影响显著(P<0.05),而对照组无显著变化。单一染毒组组织GSH含量在12d内呈峰值变化,分别于1d、3d达到最大值,12d后保持稳定,表现为恢复至对照组水平或被诱导;复合污染处理组组织GSH含量除Cd2++B[α]P(15μg/L+0.01μg/L)处理组在3d内呈峰值变化外,其他处理组均呈逐渐下降趋势,均于12d后稳定,被显著抑制。各染毒处理组组织GST、SOD活力在12d内呈峰值变化,分别于1d、3d达到最大值,12d后各处理组GST、SOD活力趋于稳定,GST活力与对照组无明显差异,而SOD活力明显高于对照组水平。由此可见,菲律宾蛤仔在Cd2+-B[α]P复合胁迫下急性毒性效应明显,组织解毒代谢酶活力表现出明显的时间、剂量效应性,鳃丝、消化盲囊GSH含量和SOD活力可作为菲律宾蛤仔Cd2+-B[α]P复合污染评价的潜在生物标志物。     

邻苯二甲酸二乙基己酯对鲤非特异性免疫的影响及遗传毒性

以水和吐温-80为对照,用5、20、80、160 mg/L的邻苯二甲酸二乙基己酯（DEHP）对鲤染毒20d,研究了DEHP对鲤非特异性免疫功能的影响及遗传毒性。结果表明: 吐温-80组与水对照组相比除红细胞总核异常率显著升高外,所测定的各项指标差异均不显著。80、160 mg/L组白细胞吞噬活力、吞噬指数,血清抗菌活力,溶菌酶活性均显著低于水对照组和吐温-80组（P0.05或P0.01）,且20 mg/L组白细胞吞噬活力、吞噬指数显著低于水对照组。与吐温-80组相比,160 mg/L组血清C3含量显著降低,5、20、80 mg/L组C3含量,5、20、80、160 mg/L组C4含量则无显著性差异。20、80、160 mg/L组C3含量,160 mg/L组C4含量显著低于水对照组（P0.05或P0.01）。160 mg/L组红细胞微核率显著高于吐温-80组,80、160 mg/L组红细胞微核率显著高于水对照组。在DEHP实验浓度范围内,红细胞核异常率、总核异常率,肝细胞DPC系数均显著高于水对照组和吐温-80组。一定浓度的DEHP对鲤具有免疫毒性和遗传毒性。       

亚致死剂量高效氯氰菊酯对蚯蚓体内生化指标的影响

采用接触滤纸法, 测定蚯蚓经亚致死剂量高效氯氰菊酯染毒24 h、48 h 和72 h 后其体内蛋白含量、超氧化物歧化酶(SOD)活力、过氧化氢酶(CAT)活力和丙二醛(MDA)含量的变化, 探讨不同染毒时间和暴露浓度对蚯蚓的毒性效应。结果表明, 在高效氯氰菊酯亚致死剂量下, 染毒24 h 时蛋白含量在50 mg·L^-1 达到最大值, 而染毒72 h 时蛋白含量在5 mg·L^-1 达到最大值, 表现为短时间内促进蛋白合成而长时间下抑制。高效氯氰菊酯对SOD 和CAT 活力的诱导作用明显, SOD 活力在低浓度激活, 高浓度抑制; CAT 活力呈现出先升高后降低的趋势; MDA 含量诱导作用不明显,短时间内随暴露浓度升高而升高, 但随染毒时间延长趋于正常水平。因此SOD 和CAT 可作为蚯蚓受到氧化胁迫的指示指标, 而MDA 无法作为指示指标。此外, 各生化指标对高效氯氰菊酯毒性效应的敏感性存在差异, SOD 活力影响最大, CAT 次之, MDA 最小。     

果寡糖对银鲫非特异性免疫功能的影响

为研究果寡糖（Fructooligosaccharides）对银鲫（Carassius auratus）非特异性免疫功能的影响,以50g左右的银鲫为实验对象,在其基础饲料中分别添加浓度为0．5g／kg（A。组）、1g／kg（A：组）、2g／kg（A,组）、4g／kg（A。组）的果寡糖,另设基础饲料为对照组（A。组）,分别于7d、14d、21d、28d、42d、56d检测银鲫血液中白细胞吞噬活性、血清溶菌酶活力、血清SOD酶活性和补体C3的含量。结果表明,A2组的白细胞吞噬活性、血清溶菌酶活力、血清SOD酶活性和补体C3的含量显著高于A0组（P〈0．05）,分别于第28、第21、第14、第14天达到最大值;A,组的白细胞吞噬活性、血清溶菌酶活力、血清SOD酶活性和补体C3的含量显著高于A0组（p〈0．05）,分别于第14、第14、第7、第14天达到最大值。A3组的补体C3的含量显著高于A2组（P〈0．05）,白细胞吞噬活性、血清溶菌酶活力、血清SOD酶活性与A2组相比差异不显著,但其活性高于A2组。A1组、A4组与A0组之间的白细胞吞噬活性、血清溶菌酶活力、血清SOD酶活性和补体C3的含量在各时间点均无显著差异。     

N,N-二甲基乙酰胺对东亚三角涡虫(Dugesia japonica)毒性效应的研究

N,N-二甲基乙酰胺(DMA)的大量应用导致其越来越多的进入环境.然而水环境中的DMA对水生生物的毒性尚不明确.通过急毒性、再生、抗氧化酶活力及彗星电泳试验.探讨DMA对东亚三角涡虫(Dugesia japonica)的毒性作用.研究发现,DMA处理涡虫24、48、72、96 h的半致死浓度(LC50)分别为27.7、18.4、10.7、6.7 g/L;浓度大于0.9 g/L的DMA会损伤再生组织,延缓涡虫完成再生;处理48 h后,DMA浓度为0～5 g/L时,涡虫体内过氧化物歧化酶(SOD)及谷胱甘肽过氧化物酶(GSH-PX)活力呈上升趋势,大于5 g/L时酶活力开始下降,而过氧化氢酶(CAT)活力在DMA浓度小于1 g/L时呈下降趋势,大于1 g/L后呈现上升趋势;DMA对涡虫DNA的损伤作用不明显,浓度达到10 g/L后才表现出遗传毒性(P<0.05).结果表明DMA对涡虫有明显的生物毒性,同时涡虫对DMA毒性的反应灵敏,可用于监测水环境DMA污染.     

羊耳菊提取物主要活性成分在大鼠体内的组织分布研究

为了研究大鼠灌胃羊耳菊提取物后7个指标成分在体内的组织分布情况,实验建立同时测定大鼠组织中4,5-二咖啡酰基奎宁酸、新绿原酸、绿原酸、3,4-二咖啡酰基奎宁酸、1,3-二咖啡酰基奎宁酸、隐绿原酸、木犀草苷的UPLC-MS/MS方法,将羊耳菊提取物灌胃给予SD大鼠,分别于给药0. 5、1. 5、5 h取其主要脏器和组织,采用UPLC-MS/MS测定各时间点下7个指标成分在脏器和组织中的分布情况。大鼠灌胃羊耳菊提取物后,对于新绿原酸,其浓度0. 5 h在小肠、肾、肺、肝达到峰值; 1. 5 h在胃、肌、脾达到峰值; 5 h在心达到峰值。对于绿原酸,其浓度0. 5 h在小肠、肾、肺、心达到峰值; 1. 5 h在胃、肌、脾、肝达到峰值。对于隐绿原酸,其浓度0. 5 h在小肠、肾、肺达到峰值; 1. 5 h时在心、肝、脾、肺、胃达到峰值。对于1,3-二咖啡酰基奎宁酸,其浓度0. 5 h在心、肺、肾、小肠达到峰值; 1. 5 h在肝、脾、肌、胃达到峰值。对于3,4-二咖啡酰基奎宁酸,其浓度0. 5 h在小肠和肾达到峰值; 1. 5 h在肝、脾、肌、胃达到峰值; 5 h在心、肺达到峰值。对于4,5-二咖啡酰基奎宁酸,其浓度0. 5 h在小肠、肾、心达到峰值; 1. 5 h在肝、脾、肌、胃达到峰值; 5 h在肺达到峰值。对于木犀草苷,其浓度0. 5h在小肠和心达到峰值; 1. 5 h在肝、脾、胃达到峰值; 5 h在肺和肾达到峰值。7个指标成分可迅速、广泛地分布在各组织器官中,脑组织中未检测到该7种成分。7种成分主要分布在胃、小肠和肾组织中,对肾脏表现出较强的亲和力,推测肾脏可能是羊耳菊的主要排泄器官之一。     

牛磺酸对小麦幼苗生长的生理效应

采用牛磺酸溶液培育小麦幼苗,测定10、100、500、1 000、5 000 mg/L的牛磺酸对小麦幼苗的光合作用PS Ⅱ光化学效率、细胞膜相对透性和膜脂过氧化以及生长的影响.结果表明,与对照组相比,适宜浓度的牛磺酸处理可促进小麦幼苗的生长,使其根长、株高、单株幼苗的干重和鲜重增加,并在一定程度上提高叶片的光化学效率,降低细胞膜相对透性和膜脂过氧化产物的含量;最适处理浓度约为500 mg/L.说明牛磺酸对小麦幼苗细胞膜有一定的保护作用.     

Effect of the EM Bokashi® Multimicrobial Probiotic Preparation on the Non-specific Immune Response in Pigs

The aim of the study was to determine the effect of EM Bokashi® on the phagocytic activity of monocytes and granulocytes, oxidative burst, SWC3, and CD11b + CD18+ expression on monocytes and granulocytes, and the serum concentration of cytokine and lysozyme in pig. 60 Sixty female piglets were divided into two groups: I – control and II – experimental. For the experimental group, a probiotic in the form of the preparation EM Bokashi® was added to the basal feed. Flow cytometry was used to determine selected non-specific immune response parameters, intracellular production of hydrogen peroxide by peripheral granulocytes and monocytes, and surface particles in peripheral blood. The EM Bokashi® preparation used in the study was found to increase phagocytic activity mainly in monocytes, with an increased percentage of phagocytic cells in the experimental group. The highest serum lysozyme concentration in the piglets in the experimental group (2.89 mg/dl), was noted on day 42 of the study. In the group of pigs receiving EM Bokashi®, the percentage of phagocytic cells with SWC3 (monocyte/granulocyte) expression was statistically significantly higher than in the control. The increase in the number of cells with SWC3 (monocyte/granulocyte) expression in the peripheral circulation in combination with the greater capacity of the cells for phagocytosis and respiratory burst confirms that the non-specific immune response was modulated in the pigs supplemented with EM Bokashi®.

     

补骨脂素对肝星状细胞(HSC-T6)增殖、氧化应激及Ⅰ型胶原分泌的影响

通过研究植物雌激素香豆素补骨脂素对体外培养的大鼠肝星状细胞HSC-T6增殖及相关因子表达的影响,为补骨脂素治疗肝纤维化提供实验依据。常规培养肝星状细胞HSC-T6,采用0.1 mmol/L的H2O2制造HSC-T6氧化应激的模型。分别用MTT法检测肝星状细胞增殖、放射免疫法检测细胞上清液中超氧化物歧化酶(SOD),丙二醛(MDA),还原性谷胱甘肽(GSH),谷胱甘肽过氧化物酶(GSH-Px)的活性和含量,ELISA法测定Ⅰ型胶原的分泌。结果表明:与正常对照组组比较,补骨脂素在浓度为10μmol/L,1μmol/L,0.1μmol/L,均呈现出抑制HSC-T6增殖的作用(P<0.05),且最佳作用时间为48 h(P<0.05);与模型组比较,补骨脂素各个浓度组能够提高SOD和GSH-Px的活性(P<0.05),并降低细胞上清液中MDA和GSH的含量(P<0.05);与模型组比较,补骨脂素各个浓度组在作用48 h后,细胞上清液中的Ⅰ型胶原的表达量均降低(P<0.05)。因此,作为植物雌激素的一种,补骨脂素能有效的抑制HSC-T6的增殖及抗HSC-T6氧化应激,很可能成为雌激素的替代品在治疗肝纤维化中。     

Effect of copper sulfate on the immune response and susceptibility to Vibrio alginolyticus in the white shrimp Litopenaeus vannamei

White shrimp Litopenaeus vannamei (Boone) held in 35 per thousand seawater were challenged with Vibrio alginolyticus at a dose of 3 x 10(5) colony-forming units (cfu) shrimp(-1), and then placed in water containing concentrations of Cu2+ at 0 (control), 1, 5, 10 and 20 mg l(-1). Mortality of shrimp in 5, 10 and 20 mg l(-1) Cu2+ was significantly higher than those in 1 mg l(-1) Cu2+ and the control solution after 24-96 h. In another experiment, L. vannamei which had been exposed to control, 1, 5, 10 and 20 mg l(-1) Cu2+ for 24, 48 and 96 h were examined for THC (total haemocyte count), phenoloxidase activity, respiratory burst (release of superoxide anion), phagocytic activity and clearance efficiency to V. alginolyticus. Copper concentrations at 1 mg l(-1) or greater for 24h resulted in decreased THC, phenoloxidase activity, phagocytic activity and clearance efficiency, whereas copper concentration at 20 mg l(-1) caused significant increase in respiratory burst of L. vannamei. In conclusion, concentration of Cu2+ at 1 mg l(-1) or greater increased the susceptibility of L. vannamei to V. alginolyticus infection by a depression in immune ability. The release of superoxide anion by L. vannamei exposed to 20 mg l(-1) Cu2+ was considered to be cytotoxic to the host.     

壬基酚对波纹巴非蛤(Paphia undulata)内脏团毒性效应

采用半静态毒性实验方法测定了壬基酚(NP)对波纹巴非蛤(Paphiaundulata)的96-hLC50值,同时研究了低、中、高3个浓度(1、10和25μg·L-1)NP胁迫下以及胁迫解除后波纹巴非蛤内脏团中超氧化物歧化酶(SOD)、谷胱甘肽(GSH)、过氧化物酶(POD)以及丙二醛(MDA)含量的变化趋势。急性毒性实验结果表明,NP对波纹巴非蛤的96-hLC50值为260μg·L-1。胁迫初期,低、中浓度组的SOD活性被极显著抑制(P<0.01),而POD活性则被极显著诱导(P<0.01),表现为典型的"毒性兴奋效应"。胁迫过程中,低、中浓度组波纹巴非蛤内脏团的SOD活性和GSH含量呈先下降后上升的趋势,而POD活性和MDA含量则呈先上升后下降的趋势;高浓度组SOD活性呈先抑制后诱导的趋势,POD活性和MDA含量呈先下降后升高再降低的趋势,而GSH含量则一直显著高于对照组。GSH和MDA含量在整个胁迫期间均出现剧烈的波动,且浓度越高其变化程度越大。胁迫解除后,低、中浓度组的各种指标逐渐恢复到对照组水平,但高浓度组与对照组仍存在着极显著差异。上述结果表明,NP对波纹巴非蛤内脏团的抗氧化酶系统造成较为明显的影响,而波纹巴非蛤则对一定程度的NP胁迫所带来的氧化损伤具有自我修复的能力,但对高浓度NP胁迫所造成的脂质过氧化损伤短期内却无法消除。     

Effect of saponin immersion on enhancement of the immune response of white shrimp Litopenaeus vannamei and its resistance against Vibrio alginolyticus

The haemocyte count, phenoloxidase (PO) activity, specific alpha(2)-macroglobulin (alpha2-M) activity, respiratory burst, superoxide dismutase (SOD) activity, glutathione peroxidase (GPx) activity, phagocytic activity, and clearance efficiency against Vibrio alginolyticus were examined when the white shrimp Litopenaeus vannamei (10.42+/-2.0g) were immersed in seawater (34 per thousand) containing different concentrations of saponin (0, 0.5, 1 and 2mgL(-1)) for 24, 48 and 72h. Hyaline cells (HC), the total haemocyte count (THC), specific alpha2-M activity, respiratory burst, SOD activity, and GPx activity directly increased with the saponin concentration, whereas PO activity was inversely related to the saponin concentration. White shrimp L. vannamei that were immersed in saponin at 1 and 2mgL(-1) showed increased phagocytic activity and clearance efficiency to V. alginolyticus over 48-72h. In another experiment, shrimp immersed in seawater containing different concentrations of saponin after 72h were challenged with V. alginolyticus at 3.2x10(5) colony-forming units (cfu)shrimp(-1), and then placed in seawater. The survival rate of shrimp immersed in seawater containing saponin at either dose was significantly higher than that of control shrimp after 12h, as well as at the termination of the experiment (5days after the challenge). It was therefore concluded that L. vannamei immersed in water containing saponin at 2mgL(-1) or less exhibited an immunomodulatory effect, as well as protection against V. alginolyticus infection.     

外源一氧化氮对渗透胁迫下小麦幼苗叶片膜脂过氧化的缓解作用

采用15%的聚乙二醇-6000(PEG-6000)对扬麦158三叶一心期的幼苗根部进行轻度渗透胁迫处理,并通过添加不同浓度的一氧化氮(nitric oxide,NO)供体硝普钠(sodium nitropussidi,SNP)和相应的对照(BO-3/NO-2),研究外源NO处理对渗透胁迫下小麦幼苗叶片膜脂过氧化作用的影响.结果发现,0.1 nnol/L的SNP能降低渗透胁迫造成的小麦幼苗叶片脂氧合酶(lipoxygenase,LOX)活性的提高,降低超氧阴离子(O-2)的产生速率和质膜相对透性的增加以及丙二醛(MDA)和H2O2的累积;0.1 mmol/L的SNP还能够诱导超氧化物歧化酶(superoxide dismutase,SOD)活性,加速脯氨酸(Pro)的累积,而0.5mmo1/L的SNP和0.1mmo1/L的NO3/NO2(对照)处理的效果则不明显.上述结果表明低浓度NO对渗透胁迫造成的膜脂过氧化有明显的缓解效应.     

Lysozyme as a local defense factor in the gastrointestinal tract of patients with chronic diseases of the digestive organs]

No microbial growth in platings of the gastric juice of patients with gastric ulcer and chronic anacidic gastritis was observed. It means that the absence of hydrochloric acid in the gastric juice does not deprive it of any antimicrobial action. The possible role of lysozyme in providing sterility of the proximal part of the gastro-intestinal tract was studied. Eighty patients with chronic diseases of the digestive organs were observed. It was noted that the levels of lysozyme in the gastric juice was high and markedly exceeded the maximum concentrations required for lysis of organisms most resistant to it. The maximum concentration was determined at pH of the gastric juice equal to 7.0-7.5 (265 gamma/ml+/-28). No lysozyme in the content of the duodenum and jejunal juice was found in most cases. Its presence in the above parts of the gastro-intestinal tract was mainly associated with microbial growth. The maximum concentration of lysozyme (40 gamma/ml) in the jejunal juice was observed in a female patient with chronic enterocolitis and significant microbial proliferation in the thin colon (more than 10(4) microbial bodies per 1 ml of the juice). Such parallelism between the presence of lysozyme in the gastric juice and microbial proliferation in it may be considered as a protective-adoptive reaction of the host.     

Bioaccumulation, oxidative stress and HSP70 expression in Cyprinus carpio L. exposed to microcystin-LR under laboratory conditions

Microcystin-LR (MC-LR) produced by cyanobacteria are potent specific hepatotoxins. So far the pathogenesis of environmental MC-LR toxicity to aquatic organisms has not been fully elucidated. In the present study the accumulation of MC-LR was investigated in various organs/tissues of Cyprinus carpio L. (C. carpio) following exposure to MC-LR for 14 d at environmentally relevant concentrations (0.1 to 10 μg L(-1)). Results showed that the presence of MC-LR enhanced toxin accumulation in all investigated organs and the highest accumulation was found in the liver of fish exposed to 5.0 μg L(-1) of MC-LR. An EPR analysis indicated ·OH intensity in liver was significantly induced at 0.1 μg L(-1) of MC-LR and then restored when the MC-LR concentration was greater than 0.1 μg L(-1). After 14-day exposure, MC-LR (1.0-10.0 μg L(-1) of MC-LR) caused a pronounced promotion of glutathione S-transferase (GST) activity and a depletion of reduced glutathione (GSH) content in fish liver, which indicated that GSH was involved in detoxification of MC-LR and the conjugation reaction of MC-LR and GSH occurred. A mild oxidative damage was evidenced by the accumulation of malondialdehyde (MDA) level at 5.0 μg L(-1) of MC-LR exposure, but which was restored when the MC-LR concentration was increased to 10.0 μg L(-1). The responses of antioxidant enzymes and the induction of HSP70 expression might contribute to MC-LR tolerance of C. carpio. However, the protein phosphatase (PP) activities were strikingly inhibited in all treated groups. Thus, the overall toxicity of environmental MC-LR on C. carpio seems to be initiated in the liver via both the ROS pathway and the PP inhibition pathway, and the latter might be more important when ambient MC-LR concentration is greater than 0.1 μg L(-1). More importantly, these results can help to support the evaluation on the potential effects of MC-LR under common environmental concentrations.     

The phagocytosis-associated respiratory burst in human monocytes is associated with increased uptake of glutathione

During the phagocytic respiratory burst, oxygen is converted to potent cytotoxic oxidants. Monocytes and macrophages are potentially long-lived, and we have hypothesized that protective mechanisms against oxidant stress are varied and fully expressed in these cells. We report here that the respiratory burst in monocytes is accompanied by an increase in the uptake of [35S]glutathione ([35S]GSH) after 20-30 min to levels up to 10-fold greater than those at baseline. By 30 min, 49% of the cell-associated radioactivity was in the cytosol, 41% was in membrane, and 10% was associated with the nuclear fraction. GSH uptake was inhibited by catalase, which removes hydrogen peroxide (H2O2), and micromolar H2O2 stimulated GSH uptake effectively in monocytes and also lymphocytes. Oxidation of GSH to glutathione disulfide with H2O2 and glutathione peroxidase prevented uptake. Acivicin, which inhibits GSH breakdown by gamma-glutamyl transpeptidase (GGT), had no effect on the enhanced uptake seen during the respiratory burst. Uptake of cysteine or cystine, possible products of GGT activity, stayed the same or decreased during the respiratory burst. These results suggest that a GGT-independent mechanism is responsible for the enhanced GSH uptake seen during the respiratory burst. We describe here a sodium-independent, methionine-inhibitable transport system with a Km (8.5 microM) for GSH approximating the plasma GSH concentration. These results suggest that monocytes have a specific GSH transporter that is triggered by the release of H2O2 during the respiratory burst and that induces the uptake of GSH into the cell. Such a mechanism has the potential to protect the phagocyte against oxidant damage.