苯并(a)芘与壬基酚对河川沙塘鳢的联合毒性研究

为探究环境内分泌干扰物联合毒性对鱼类的影响,选取苯并芘(benzo[a]pyrene,BaP)及千幕酚(4-nonlyphenol,NP)对河川沙塘鳢Odontobutis potamophila进行单独和联合毒性研究.研究了NP和BaP对河川沙塘鳢血清雌二醇(E2)、卵黄蛋白原(Vtg)、血清谷草转氨酶(GOT)以及肝脏7-乙氧基-3-异吩咏唑酮-脱乙基酶(7-ethoxyresoufin-O-deethylase,EROD)和超氧化物岐化酶(SOD)的影响.结果 表明,BaP单一暴露时,随着BaP剂量浓度的升高雌鱼血清E2含量下降,肝脏EROD活性升高;25 mg/kg BaP试验组雌鱼肝脏EROD活性显著高十对照组;肝脏SOD和血清GOT活性与对照无筹异;NP和BaP联合暴露中,200 mg/kg NP+10 mg/kg BaP、200 mg/kg NP+2 mg/kg BaP试验组雄性个体血清Vtg平均含量比200 mg/kg NP组低50%左右,而血清E2含最显著高于对照组,肝脏EROD酶活性、血清GOT活性变化与BaP剂量浓度呈正相关,而肝脏SOD酶活性则与BaP剂量浓度呈负相关;200 mg/kg NP+25 mg/kg BaP试验组肝脏SOD活性显著低于对照组,而血清GOT活性则显著高于对照组.显示NP和BaP联合作用时BaP可拮抗NP对雄鱼Vtg的诱导效应;200 mg/kg NP+2 mg/kg BaP可导致河川沙塘鳢肝脏肝细胞损伤.     

淮河淮南段与巢湖水质污染对鲫鱼（Carassius auratus）的毒性效应

研究了枯水期淮河淮南段及巢湖西半湖水质污染对鲫鱼的毒性效应。从淮河淮南段与巢湖采集鱼类样本,并以未受人为污染的安丰塘鱼类为对照,分析了鲫鱼肝脏丙二醛（Malondialdehyde,MDA）含量、超氧化物歧化酶（Superoxide dismutase,SOD）活性、谷胱甘肽硫转移酶（Glutathione S-transferase,GST）活性、7-乙氧基异吩恶唑-O-脱乙基酶（7-ethoxyresorufin-O-deethylase,EROD）活性及DNA单链损伤情况,结果表明,淮河淮南段鲫鱼肝脏MDA含量、SOD活性、GST活性、EROD活性均高于对照组,分别是对照组的2.88、1.48、2.03和3.93倍;巢湖鲫鱼肝脏MDA含量、SOD活性、EROD活性均高于对照组,分别是对照组的2.28、1.85和2.74倍。肝细胞DNA单链断裂的测定显示淮河淮南段与巢湖的水质污染均对鲫鱼有遗传毒性。     

石菖蒲不同部位对戊四唑点燃大鼠神经肽Y含量的影响

目的:研究石菖蒲不同部位对戊四唑点燃癫痫模型大鼠神经肽Y含量的影响.方法:SD大鼠80只,腹腔注射戊四唑(PTZ)溶液35mg·kg1体重,隔天1次,共14次.点燃成功的大鼠,分8组,每天灌胃1次,分别给予石菖蒲挥发油50mg·kg-1体重、石菖蒲去油水提液高剂量28g·kg-1体重、中剂量14·kg-1体重、低剂量7g·kg-1体重、β-细辛醚100mg·kg-1体重、α-细辛醚70mg·kg-1体重,阳性对照组给予丙戊酸钠(VPA)126mg·kg-1体重治疗,模型组给予同量生理盐水.另设正常组5只,正常喂养,不作任何处理.治疗36天后注射同剂量戊四唑点燃测试药效,断头取脑,分取海马用放免法测定神经肤Y(NPY)含量.结果:与正常组比较,治疗后造模的各组大鼠海马神经肽Y含量升高,石菖蒲去油水提液低剂量组、阳性组有统计学意义(P<0.01),模型组与正常组比较有统计学意义(P<0.05).结论:治疗后造模各组大鼠海马神经肤Y含量升高,起抗癫痫作用.     

孕期大鼠暴露PFOS对胎鼠肝脏毒性的影响

目的:研究在孕期暴露PFOS对胎鼠的肝脏毒性的影响.方法:将孕期为12天的16只SD雌性大鼠,随机分为4组给予不同剂量的PFOS[0(对照),5,10,20 mg·kg-1],连续灌胃7天,在GD19天时对母鼠和胎鼠的体重、胎鼠肝脏的生化指标、母鼠血清的生化指标进行了相应的检测.结果:与对照组相比,母鼠体重在20 mg·kg-1组显著下降(P＜0.001);胎鼠的体重和体长在20mg·kg-1组显著下降(P＜0.001);胎鼠的肝脏重量降低,呈剂量依赖性,并伴有肝细胞浊肿、变性甚至坏死;10 mg· kg-1组胎鼠肝脏中的酶活性(ALT、AST、GGT和ALP等)显著升高(P＜0.001);母鼠血清的大部分生化指标未发生明显变化.结论:孕期大鼠暴露在PFOS的环境下会严重损伤胎鼠的肝脏功能.     

姜黄素对小鼠胆汁淤积性肝纤维化的改善作用及其机制研究*

目的:探讨姜黄素对小鼠胆管结扎所致的胆汁淤积性肝纤维化的保护作用,为肝纤维化治疗提供新的治疗方法。方法:42只健康成年雄性BALB/c小鼠随机分为假手术(n=6)处理组、假手术+姜黄素(n=6)处理组、胆管结扎(BDL)处理组(n=10)、BDL+姜黄素处理组(n=10),BDL+姜黄素+锌原卟啉(ZnPP)处理组(n=10)。BDL手术7 d后,假手术+姜黄素组、BDL+姜黄素组每日给予姜黄素(30 mg / kg)腹腔注射;BDL+姜黄素+ZnPP组每日给予姜黄素(30 mg / kg)以及nPP(50 μmol/ kg)腹腔注射;对于假手术组和BDL组,小鼠每天一次腹膜内注射等体积的盐水。整个给药过程持续7 d。小鼠BDL14 d后,取血和肝脏组织,检测谷草转氨酶(AST)、谷丙转氨酶(ALT)水平,观察肝组织病理形态变化、肝纤维化情况、检测肝组织中血红素加氧酶-1(HO-1)的蛋白表达。结果:与假手术组相比,BDL组小鼠肝脏胆囊肿大,血清谷草转氨酶(ALT)、谷丙转氨酶(AST)水平显著升高 (P＜0.05),同时,天狼星红染色及促纤维化相关基因的qRT-PCR结果显示肝脏出现胶原蛋白沉积,巨噬细胞及中性粒细胞免疫组化结果显示肝脏出现炎性细胞浸润;与BDL组相比,姜黄素治疗组血清ALT、AST水平明显降低(P＜0.05),胶原蛋白沉积及炎性细胞浸润情况有所改善,同时,补充姜黄素后HO-1表达升高(P＜0.05);对姜黄素治疗组给予HO-1活性抑制剂ZnPP发现,姜黄素对肝损伤的保护作用被逆转。结论:姜黄素可以改善BDL所致的肝脏炎症及肝纤维化,这种保护作用可能与姜黄素调节HO-1活性有关。     

2,4,6－三氯苯酚诱导鲫鱼肝脏自由基的产生及其氧化应激

采用电子顺磁共振的方法,研究了鲫鱼腹腔注射2,4,6-三氯苯酚(2,4,6-TCP)不同时间(4、8、12、24、72 h)后其肝脏自由基强度的变化、氧化应激反应及其损伤机理.结果表明：2,4,6-TCP极显著促进了鲫鱼肝脏自由基的产生;鲫鱼肝脏内超氧化物歧化酶 (SOD) 与谷胱甘肽硫转移酶 (GST) 的活性受到显著诱导 ,过氧化氢酶 (CAT) 活性受到抑制,还原型谷胱甘肽 (GSH) 含量与对照组无明显差异,氧化型谷胱甘肽 (GSSG) 含量显著升高 ,丙二醛(MDA) 含量极显著增加.     

矢车菊素-3-葡萄糖苷对重金属镉胁迫后大鼠氧化损伤的缓解作用

为研究矢车菊素-3-葡萄糖苷(Cy-3-glu)对重金属镉胁迫后的脂质过氧化和氧化应激反应的缓解作用,将雄性SD大鼠随机分成4组(每组5只)分别灌服Cy-3-glu(100、200 mg·kg-1),同时腹腔注射重金属镉(Cd),收集组织样本进行测定。结果显示,灌服Cy-3-glu的SD大鼠能明显缓解由重金属镉胁迫导致的大鼠体重下降,并且肝脏、肾脏、睾丸等脏器指数随Cy-3-glu剂量的升高而呈显著或极显著上升;Cy-3-glu能显著改善由重金属镉引起的肝脏ROS、MDA含量升高;抗氧化酶系活性也随之发生改变,Cy-3-glu(200 mg·kg-1)保护组能够显著提高大鼠SOD酶活,但对于POD、CAT酶活性并未表现一定的量效关系。表明Cy-3-glu可以使肝脏的抗氧化潜力明显恢复,通过清除自由基、缓解脂质过氧化、激活相关抗氧化酶活性,从而降低机体的ROS、MDA含量,缓解由重金属镉引起的大鼠肝脏氧化应激反应,发挥保护作用。     

11-羰基-β-乙酰乳香酸抗氧化胃保护作用及机制研究

目的:研究11-羰基-β-乙酰乳香酸(AKBA)的抗氧化作用及胃保护效果。方法:30只SD大鼠随机分为5组:正常组(生理盐水5 mL/kg),模型组(吲哚美辛48 mg/kg),西咪替丁组(100 mg/kg),低剂量AKBA组(100 mg/kg),高剂量AKBA组(200mg/kg)。预给药1小时后,用吲哚美辛(48 mg/kg)灌胃造模,评价溃疡指数(UI)、胃内容物酸度(p H)、胃壁黏液量(GWM)、前列腺素E2(PGE-2)及一氧化氮(NO)的含量,并检测超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的活性,丙二醛(MDA)含量及核转录相关因子2(Nrf2)和血红素加氧酶1(HO-1)的表达量。结果:(1)与造模组相比,AKBA高剂量组(P0.05)与西咪替丁组(P0.001)显著降低了吲哚美辛诱导的胃粘膜损伤,AKBA低剂量组的差异无统计学意义;(2)AKBA与西咪替丁均显著升高胃内容物p H(P0.001)(AKBA低剂量组P0.05),增加GWM含量(P0.001);(3)与造模组相比,AKBA及西咪替丁组均显著增高PGE-2及NO含量(P0.001);(4)与造模组相比,AKBA及西咪替丁组均显著增高SOD活性(P0.001)(AKBA低剂量组P0.05)及CAT活性(P0.001)并降低了MDA含量(P0.001);(5)与造模组相比,AKBA高剂量组及西咪替丁组促进Nrf2及HO-1表达明显增高(P0.05)。结论:AKBA有较好的胃保护效果,同时可以通过升高GWM、降低胃内容物p H,升高NO含量,阻止PGE-2的降低,同时恢复SOD、CAT的活性,降低MDA含量,促进Nrf2及HO-1的表达发挥胃黏膜保护的作用。     

苯并[a]芘暴露对三疣梭子蟹鳃、肝胰腺组织毒理学指标的影响

本文研究了三疣梭子蟹(Portunus trituberculatus)在对苯并[a]芘(BaP)富集(15 d)、释放(15d)过程中其鳃和肝胰腺组织的4种毒理学指标的响应.4种毒理学指标分别为7-乙氧基异吩噁唑酮-脱乙基酶(EROD)、谷胱甘肽硫转移酶(GST)、超氧化物歧化酶(SOD)和脂质过氧化(LPO).设置了0.05 μg/L和0.45 μg/L两个实验组以及海水和丙酮对照组.结果显示,在富集阶段,与海水对照组相比,第1天时0.05 μg/L和0.45μg/L实验组鳃、肝胰腺组织的各毒理指标均显著受到诱导(P＜0.05),诱导程度随BaP暴露浓度的增加而增大.而后鳃、肝胰腺组织的EROD、GST活性以及鳃组织的SOD活性达到峰值后下降,肝胰腺组织的SOD活性以及鳃、肝胰腺组织的丙二醛(MDA)含量则持续增加.鳃组织的EROD、GST、SOD活性到达峰值时间早于肝胰腺组织,其活性以及MDA含量也低于肝胰腺组织.在释放阶段,0.45pg/L实验组鳃组织的SOD活性,0.05μ-g/L和0.45 μg/L两个实验组肝胰腺组织的SOD活性均依然显著高于同期海水对照组水平(P＜0.05),其余各浓度实验组鳃、肝胰腺组织均能恢复到同期海水对照组水平(P＞ 0.05).实验结果表明,三疣梭子蟹的鳃组织对于BaP暴露响应时间比肝胰腺组织更早,但均具有一定的恢复能力.     

硫酸软骨素对慢性酒精中毒大鼠脑损伤的保护作用

目的:探讨硫酸软骨素对慢性酒精中毒脑损伤的作用及可能机制.方法:雄性 Wistar 大鼠60只随机分为6组,酒精模型组以剂量为8ml·kg-1·d-150%的酒精每天灌胃一次,纳洛酮药物组给予乙醇半小时后腹腔注射纳洛酮0.08mg·k-1·d-1,硫酸软骨素低、中、高剂量干预组在酒精模型组的基础上分别给予硫酸软骨素50、100、150mg·kg-1·d-1,空白对照组给予等体积的蒸馏水,持续2周;第三周把50%的酒精的剂量递增为12mg·kg-1·d-1,持续灌胃6周.在第八周末实验结束后取血,分离血清,留取脑组织.HE染色观察各组大鼠神经细胞的变化.生化测定各组大鼠血清及脑组织匀浆中谷胱甘肽过氧化物酶(GSH-PX)和超氧化物歧化酶(SOD)的活性以及脂质过氧物终未产物丙二醛(MDA);并测定脑皮质中β-内啡肽含量(β-EP).结果:模型组大鼠大脑皮质和海马区神经元数量明显减少,神经细胞排列紊乱.硫酸软骨素中剂量组大鼠大脑皮质和海马区神经细胞排列层次较清晰.与酒精组相比较,硫酸软骨素中剂量组大鼠血清和脑组织匀浆中MDA含量明显降低(P<0.01),脑皮质中β-内啡肽含量明显降低(P<0.01);GSH-PX含量及SOD活性显著升高(P<0.01).结论:硫酸软骨素对大鼠慢性酒精中毒脑损伤具有保护作用.     

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.     

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.     

Structure and function of S-adenosylhomocysteine hydrolase

In mammals, S-adenosylhomocysteine hydrolase (AdoHcyase) is the only known enzyme to catalyze the breakdown of S-adenosylhomocysteine (AdoHcy) to homocysteine and adenosine. AdoHcy is the product of all adenosylmethionine (AdoMet)-dependent biological transmethylations. These reactions have a wide range of products, and are common in all facets of biometabolism. As a product inhibitor, elevated levels of AdoHcy suppress AdoMet-dependent transmethylations. Thus, AdoHcyase is a regulator of biological transmethylation in general. The three-dimensional structure of AdoHcyase complexed with reduced nicotinamide adenine dinucleotide phosphate (NADH) and the inhibitor (1′R, 2′S, 3′R)-9-(2′,3′-dihyroxycyclopenten-1-yl)adenine (DHCeA) was solved by a combination of the crystallographic direct methods program, SnB, to determine the selenium atom substructure and by treating the multiwavelength anomalous diffraction data as a special case of multiple isomorphous replacement. The enzyme architecture resembles that observed for NAD-dependent dehydrogenases, with the catalytic domain and the cofactor binding domain each containing a modified Rossmann fold. The two domains form a deep active site cleft containing the cofactor and bound inhibitor molecule. A comparison of the inhibitor complex of the human enzyme and the structure of the rat enzyme, solved without inhibitor, suggests that a 17° rigid body movement of the catalytic domain occurs upon inhibitor/substrate binding.     

Chiral Separation of G‐type Chemical Warfare Nerve Agents via Analytical Supercritical Fluid Chromatography

Chemical warfare nerve agents (CWNAs) are extremely toxic organophosphorus compounds that contain a chiral phosphorus center. Undirected synthesis of G‐type CWNAs produces stereoisomers of tabun, sarin, soman, and cyclosarin (GA, GB, GD, and GF, respectively). Analytical‐scale methods were developed using a supercritical fluid chromatography (SFC) system in tandem with a mass spectrometer for the separation, quantitation, and isolation of individual stereoisomers of GA, GB, GD, and GF. Screening various chiral stationary phases (CSPs) for the capacity to provide full baseline separation of the CWNAs revealed that a Regis WhelkO1 (SS) column was capable of separating the enantiomers of GA, GB, and GF, with elution of the P(+) enantiomer preceding elution of the corresponding P(–) enantiomer; two WhelkO1 (SS) columns had to be connected in series to achieve complete baseline resolution. The four diastereomers of GD were also resolved using two tandem WhelkO1 (SS) columns, with complete baseline separation of the two P(+) epimers. A single WhelkO1 (RR) column with inverse stereochemistry resulted in baseline separation of the GD P(–) epimers. The analytical methods described can be scaled to allow isolation of individual stereoisomers to assist in screening and development of countermeasures to organophosphorus nerve agents. Chirality 26:817–824, 2014. © 2014 The Authors. Chirality published by John Wiley Periodicals, Inc.     

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.     

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.     

In vitro studies of the rabbit immune system. IV. Differential mitogen responses of isolated T and B cells.

The mitogenic responses of separated rabbit lymphocyte populations functionally analogous to mouse T and B cells have been tested in vitro. Purified T cells were prepared by passage over nylon wool (NW) and purified B cells prepared by treatment with antithymocyte serum and complement (ATS + C). ATS + C kills 70% of peripheral blood lymphocytes (PBL's) and 50% of the spleen cells while passage over NW yields 40% of the applied PBL's and 5–23% of the applied spleen cells. NW-purified T cells from the spleen or PBL's respond fully to concanavalin A (Con A) but have a reduced response to phytohemaglutinin (PHA) and little or no response to goat anti-rabbit immunoglobulin (anti-Ig). PBL's that survive ATS + C (B cells) are stimulated by anti-Ig but not by Con A or PHA. B cells purified from spleen do not respond to Con A or PHA but will respond to anti-Ig under appropriate conditions. A full spleen B-cell response to anti-Ig required removal of Ig produced by the cultures that blocked anti-Ig stimulation. It is concluded that, for rabbit lymphocytes, Con A and PHA are primarily T-cell mitogens and that anti-Ig is primarily a B-cell mitogen. However, the mitogen response of unfractionated PBL or spleen cell populations indicates an overlap in reactivity. This could be due to cells sharing T and B properties, alteration of cell populations by the fractionation procedures used, or recruitment of one population in the presence of a mitogenic response of the other population.     

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.     

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。     

A chromium-tolerant plant growing in Cr-contaminated land

In this paper, a kind of Typhaceae plant species, Typha angustifolia L, with a high tolerance to Cr is described. Experiments were carried out to examine its ability to tolerant Cr and its physiological response. The results showed that there was no difference in growth, plant height, and biomass response to external Cr (VI) between the plants exposed to 100 microM Cr (VI) and control (0 microM), while increasing Cr levels to 200-800 microM induced a significant decrease in plant height and biomass, but no significant injury was detected, even for the plants exposed to 800 microM Cr. Chromium induced significant increases in superoxide dismutase (SOD) and peroxidase (POD) activities. Meanwhile, a significantly positive correlation was found between Cr and Mn or Cu in leaves and roots, respectively. The Cr tolerance of the plant appeared to be associated with the enhancement of SOD and POD activities and the improvement in uptake and translocation of the essential microelements.