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1.
摘要 目的:探讨LncRNA-NEAT1对妊娠期高血压大鼠JAK2/STAT3信号通路、炎症反应和妊娠结局的影响。方法:采用注射L-精氨酸甲酯的方法构建妊娠期高血压大鼠模型。采用Western blot检测JAK2/STAT3信号通路蛋白表达;采用ELISA法检测炎症因子和血管内皮损伤因子。观察并记录大鼠24 h蛋白尿、尾静脉压和死胎率。结果:与空白组相比,模型组、LncRNA-NEAT1过表达组、LncRNA-NEAT1抑制组JAK2、STAT3的蛋白表达水平明显更高(P<0.05);与模型组相比,LncRNA-NEAT1抑制组JAK2、STAT3的蛋白表达水平明显更低(P<0.05),而LncRNA-NEAT1过表达组JAK2、STAT3的蛋白表达水平明显更高(P<0.05);与空白组相比,模型组、LncRNA-NEAT1过表达组、LncRNA-NEAT1抑制组ET-1和sICAM-1水平明显更高,而NO水平明显更低(P<0.05);与模型组相比,LncRNA-NEAT1过表达组、LncRNA-NEAT1抑制组ET-1和sICAM-1水平明显更高(P<0.05),而NO水平明显更低(P<0.05),而LncRNA-NEAT1过表达组ET-1和sICAM-1表达水平明显更高,而NO明显更低(P<0.05);与空白组相比,模型组、LncRNA-NEAT1过表达组、LncRNA-NEAT1抑制组TNF-α、IL-1β、IL-18表达水平明显更高(P<0.05);与模型组相比,LncRNA-NEAT1抑制组TNF-α、IL-1β、IL-18表达水平明显更低(P<0.05),而LncRNA-NEAT1过表达组TNF-α、IL-1β、IL-18表达水平明显更高(P<0.05);与空白组相比,模型组、LncRNA-NEAT1过表达组、LncRNA-NEAT1抑制组尾静脉压和24h蛋白尿水平明显更高(P<0.05);与模型组相比,LncRNA-NEAT1抑制组尾静脉压和24 h蛋白尿表达水平明显更低(P<0.05),而LncRNA-NEAT1过表达组尾静脉压和24 h蛋白尿表达水平明显更高(P<0.05);LncRNA-NEAT1过表达组(21.56%)死胎率显著高于模型组(16.72%)和LncRNA-NEAT1抑制组(5.65%)。结论:妊娠期糖尿病大鼠LncRNA-NEAT1的表达下调可抑制JAK2/STAT3信号通路的表达并下调下游促炎因子的表达,进而缓解血管内皮损伤降低死胎率。  相似文献   

2.
摘要 目的:探讨苍耳子对慢性鼻-鼻窦炎大鼠炎症反应、NLRP3炎症小体及JAK2STAT3信号通路的影响。方法:选择清洁级SD大鼠40只作为研究对象。将40只大鼠随机分为5组。采用鼻腔内注射金黄色葡萄球菌悬浊液的方法构建慢性鼻-鼻窦炎大鼠模型。空白对照组(8只)、模型组(8只)、低剂量组(7.5 mg/kg,8只)、中剂量组(15 mg/kg,8只)和高剂量组(30 mg/kg,8只)。采用埋藏食物小球实验进行嗅觉功能检查,采用qRC-PCR检测JAK2/STAT3信号通路和NLRP3、ACS、caspase-1的mRNA表达水平并采用ELISA法检查大鼠血液样本中肿瘤坏死因子-α(TNF-α)和IL-1β、IL-18的表达水平。结果:建模前,各组大鼠找到食物小球的时间比较(P>0.05);治疗后7 d和治疗完成时,与对照组相比,模型组、低剂量组、中剂量组和高剂量组找到食物小球的时间明显更长(P<0.05),高剂量组找到食物小球的时间明显短于模型组、低剂量组、中剂量组(P<0.05)。与对照组相比,模型组、低剂量组、中剂量组和高剂量组JAK2 mRNA、STAT3 mRNA相对表达水平明显更高(P<0.05),高剂量组JAK2 mRNA、STAT3 mRNA相对表达水平明显低于模型组、低剂量组、中剂量组(P<0.05)。与对照组相比,模型组、低剂量组、中剂量组和高剂量组TNF-α、IL-1β、IL-18表达水平明显更高(P<0.05),高剂量组TNF-α、IL-1β、IL-18表达水平明显低于模型组、低剂量组、中剂量组(P<0.05)。与对照组相比,模型组、低剂量组、中剂量组和高剂量组NLRP3 mRNA、ACS mRNA、caspase-1 mRNA相对表达水平明显更高(P<0.05),高剂量组NLRP3 mRNA、ACS mRNA、caspase-1 mRNA相对表达水平明显低于模型组、低剂量组、中剂量组(P<0.05)。结论:CRS大鼠采用苍耳子挥发油进行治疗可通过调控JAK2/STAT3信号通路的表达和NLRP3炎症小体的表达,从而抑制下游炎症因子的过度分泌,最终为缓解CRS病情和改善嗅觉功能做出贡献。  相似文献   

3.
摘要 目的:探讨BNP/NPR-A/BKCa信号通路在大鼠神经痛形成中的作用及机制研究。方法:选取SPF级大鼠作为研究对象,并构建神经痛病理性疼痛大鼠模型。并分为空白对照组、假手术组、A组(20 ng/mL BNP梢内注射)、B组(50 ng/mL BNP梢内注射)和C组(100 ng/mL BNP梢内注射)。采用qRT-PCR和Western blot检测NPR-A和BKCa的mRNA和蛋白表达水平。采用ELISA法检查炎症因子。全细胞膜片钳技术检测痛觉神经元BKCa通道电流;对大鼠进行机械性痛觉过敏测试和温度性痛觉敏感测试。结果:与空白组相比,模型组、A、B和C组PWT和PWL明显更低(P<0.05);与模型组相比,A、B和C组PWT和PWL明显更高,且C组大于B和A组,B组大于A组(P<0.05)。与空白组相比,模型组NPR-A的蛋白和mRAN水平明显更高,而BKCa-α明显更低(P<0.05);与模型组相比,A、B和C组NPR-A和BKCa-α的蛋白和mRNA明显更高,且C组大于B和A组,B组大于A组(P<0.05)。各电压水平,与空白组相比,模型组、A、B和C组BKCa-α电流水平明显更低(P<0.05);与模型组相比,A、B和C组BKCa-α电流水平明显更高,且C组大于B和A组,B组大于A组(P<0.05)。与空白组相比,模型组、A、B和C组TNF-α、IL-6和IL-18水平明显更高(P<0.05);与模型组相比,A、B和C组TNF-α、IL-6和IL-18水平明显更低,且C组小于B和A组,B组小于A组(P<0.05)。结论:靶向上调BNP的表达水平可增加BKCa的表达及BKCa电流,同时BNP的表达上调还有助于抑制炎症因子水平,从而达到多途径缓解疼痛的目的。  相似文献   

4.
摘要 目的:探讨参苓白术散联合针刺对溃疡性结肠炎大鼠内质网应激、炎症反应的作用机制。方法:采用三硝基苯磺酸的方法构建溃疡性结肠炎大鼠模型。给予大鼠参苓白术散联合针刺干预。采用ELISA法检测大鼠病变结肠的炎症反应和氧化应激水平;采用肉眼观察各组结肠组织形态学评分;采用Western blot 检测大鼠内质网应激相关蛋白的表达。结果:与空白组相比,模型组、针刺组、参苓白术散、参苓白术散组联合针刺组大鼠体质量更低(P<0.05);与模型组相比,针刺组、参苓白术散、参苓白术散组联合针刺组溃疡指数评分和大鼠体质量更低(P<0.05),且参苓白术散组联合针刺组明显低于针刺组和参苓白术散组;与空白组相比,模型组、针刺组、参苓白术散、参苓白术散组联合针刺组ROS、GSH-Px、MDA更高(P<0.05);与模型组相比,针刺组、参苓白术散、参苓白术散组联合针刺组ROS、GSH-Px、MDA更低(P<0.05),且参苓白术散组联合针刺组明显低于针刺组和参苓白术散组;与空白组相比,模型组、针刺组、参苓白术散、参苓白术散组联合针刺组TNF-α、IL-1β、IL-18更高(P<0.05);与模型组相比,针刺组、参苓白术散、参苓白术散组联合针刺组TNF-α、IL-1β、IL-18更低(P<0.05),且参苓白术散组联合针刺组低于针刺组和参苓白术散组;与空白组相比,模型组、针刺组、参苓白术散、参苓白术散组联合针刺组GRP78、p-PERK、p-eIF2α更高(P<0.05);与模型组相比,针刺组、参苓白术散、参苓白术散组联合针刺组GRP78、p-PERK、p-eIF2α更低(P<0.05),且参苓白术散组联合针刺组明显低于针刺组和参苓白术散组。结论:参苓白术散组联合针刺可有效抑制溃疡性结肠炎大鼠内质网应激,进而抑制炎症反应和氧化应激反应,并促进溃疡性结肠炎大鼠病变病情转归。  相似文献   

5.
摘要 目的:探讨Snail1基因表达在妊娠期糖尿病大鼠氧化应激及肝脏损伤的作用机制。方法:健康成年C57BL/6雌性大鼠32只作为研究对象。采用高脂喂养联合小剂量链脲佐菌素注射的方式构建妊娠期糖尿病大鼠模型。将所有大鼠分为正常妊娠组,正常妊娠+Snail1过表达组,妊娠期糖尿病组,妊娠期糖尿病+Snail1过表达组。采用qRT-PCR检测大鼠Snail1的mRNA表达水平,并检测大鼠妊娠期体重、氧化应激指标、炎症指标和肝功能指标。结果:与正常妊娠组相比,正常妊娠+Snail1过表达组、妊娠期糖尿病组、妊娠期糖尿病+Snail1过表达组的孕鼠体重、胎鼠体重、胎盘重量、Snail1 mRNA,明显更高(P<0.05),且妊娠期糖尿病+Snail1过表达组孕鼠体重、胎鼠体重、胎盘重量、Snail1 mRNA均显著高于正常妊娠+Snail1过表达组和妊娠期糖尿病组(P<0.05);与正常妊娠组相比,正常妊娠+Snail1过表达组、妊娠期糖尿病组、妊娠期糖尿病+Snail1过表达组的FBG、FINS、HOMA-IR明显更高(P<0.05),且妊娠期糖尿病+Snail1过表达组FBG、FINS、HOMA-IR均显著高于正常妊娠+Snail1过表达组和妊娠期糖尿病组(P<0.05);与正常妊娠组相比,正常妊娠+Snail1过表达组、妊娠期糖尿病组、妊娠期糖尿病+Snail1过表达组的ROS、GSH-Px、MDA明显更高(P<0.05),且妊娠期糖尿病+Snail1过表达组ROS、GSH-Px、MDA均显著高于正常妊娠+Snail1过表达组和妊娠期糖尿病组(P<0.05);与正常妊娠组相比,正常妊娠+Snail1过表达组、妊娠期糖尿病组、妊娠期糖尿病+Snail1过表达组的TNF-α、IL-1β、IL-18明显更高(P<0.05),且妊娠期糖尿病+Snail1过表达组TNF-α、IL-1β、IL-18均显著高于正常妊娠+Snail1过表达组和妊娠期糖尿病组(P<0.05);与正常妊娠组相比,正常妊娠+Snail1过表达组、妊娠期糖尿病组、妊娠期糖尿病+Snail1过表达组的GPT、GOT、ALP明显更高(P<0.05),且妊娠期糖尿病+Snail1过表达组GPT、GOT、ALP均显著高于正常妊娠+Snail1过表达组和妊娠期糖尿病组(P<0.05)。结论:妊娠期糖尿病大鼠Snail1基因的表达上调可加重糖脂代谢紊乱,并激活下游氧化应激和炎症反应,进而加重大鼠肝脏损伤。  相似文献   

6.
摘要 目的:基于高迁移率族蛋白B1(HMGB1)/Toll样受体4(TLR4)/核因子κB(NF-κB)信号通路探讨忍冬苷对脓毒症肝损伤大鼠的影响。方法:60只雄性SD大鼠随机分为模型组、对照组、阳性对照组(地塞米松10 mg/kg)、忍冬苷低剂量(7.5 mg/kg)、忍冬苷中剂量(15 mg/kg)、忍冬苷高剂量(30 mg/kg)组,每组10只。采用盲肠结扎穿刺法建立大鼠脓毒症模型。实验结束后麻醉大鼠取血制备血清,检测血清中超氧化物歧化酶(SOD)活性和丙二醛(MDA)、白介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、白介素-10(IL-10)含量;分离肝组织称重,计算肝脏指数,一部分用于HE染色观察肝组织病理变化,一部分用于制备组织匀浆检测组织中肝功能指标谷丙转氨酶(ALT)、天冬氨酸转氨酶(AST)活性及HMGB1、TLR4、NF-κB蛋白表达。结果:与对照组比较,模型组大鼠血清中MDA、TNF-α、IL-6含量、肝脏指数以及肝组织中AST、ALT活性、HMGB1、TLR4、NF-κB蛋白表达显著增加(P<0.05),SOD活性与IL-10含量显著下降(P<0.05);且肝组织出现明显病灶,肝细胞水肿变性,大量炎性细胞浸润。与模型组比较,阳性对照组与忍冬苷各剂量组大鼠血清中MDA、TNF-α、IL-6含量、肝脏指数以及肝组织中AST、ALT活性、HMGB1、TLR4、NF-κB蛋白表达显著降低(P<0.05),SOD活性与IL-10含量显著升高(P<0.05);忍冬苷低、中剂量组仍可见病灶和水肿,但病变减轻;地塞米松组与忍冬苷高剂量组肝细胞结构趋于正常,未发现病灶。与阳性对照组比较,忍冬苷低、中剂量组大鼠血清中MDA、TNF-α、IL-6含量、肝脏指数以及肝组织中AST、ALT活性、HMGB1、TLR4、NF-κB蛋白表达显著升高(P<0.05),SOD活性与IL-10含量显著降低(P<0.05);忍冬苷高剂量组上述指标无显著差异(P>0.05)。结论:忍冬苷通过下调HMGB1/TLR4/NF-κB信号通路的表达,抑制氧化应激,减轻炎症反应,改善肝功能,发挥对脓毒症肝损伤的保护作用。  相似文献   

7.
摘要 目的:探讨甜橙黄酮通过AMP依赖的蛋白激酶(AMPK)/哺乳动物雷帕霉素靶蛋白(mTOR)信号通路对呼吸道合胞病毒(RSV)感染大鼠肺组织损伤的改善作用。方法:将30只雄性Wistar大鼠分为对照组、模型组、甜橙黄酮低剂量组(14 mg/kg)、甜橙黄酮中剂量组(28 mg/kg)、甜橙黄酮高剂量组(56 mg/kg)、甜橙黄酮高剂量+AICAR组(56 mg/kg+500 mg/kg的AMPK激活剂AICAR),计算大鼠肺指数。实时荧光定量聚合酶链式反应(qRT-PCR)法测定肺组织RSV病毒载量,酶联免疫吸附(ELISA)法测定大鼠肺泡灌洗液炎症因子水平,HE染色测定肺组织病理,蛋白免疫印迹(Western blot)法测定AMPK/mTOR通路蛋白表达。结果:与对照组相比,模型组大鼠肺组织存在炎性浸润,排列松散,肺指数、肺组织RSV病毒载量、肺泡灌洗液白细胞介素(IL)-1β、IL-6、肿瘤坏死因子-α(TNF-α)水平、炎症评分、p-AMPK/AMPK、mTORC1蛋白表达升高(P<0.05);与模型组相比,甜橙黄酮低剂量组、甜橙黄酮中剂量组、甜橙黄酮高剂量组大鼠肺组织损伤减轻,大鼠肺指数、肺组织RSV病毒载量、肺泡灌洗液IL-1β、IL-6、TNF-α水平、炎症评分、p-AMPK/AMPK、mTORC1蛋白表达降低(P<0.05);与甜橙黄酮高剂量组相比,甜橙黄酮高剂量+AICAR组大鼠肺组织损伤加重,肺指数、肺组织RSV病毒载量、肺泡灌洗液IL-1β、IL-6、TNF-α水平、炎症评分、p-AMPK/AMPK、MTORC1蛋白表达升高(P<0.05)。结论:甜橙黄酮可能通过抑制AMPK/mTOR信号通路发挥对RSV诱导的大鼠抗炎、抗病毒、抗肺部损伤作用。  相似文献   

8.
摘要 目的:研究桂枝茯苓胶囊对慢性盆腔炎(CPID)大鼠粘连修复相关指标、免疫功能及肿瘤坏死因子-α(TNF-α)、白细胞介素-2(IL-2)的影响。方法:选择SD清洁级雌性大鼠60只,根据随机数字表法将其分成6组,每组10只,分别为对照组、假手术组、模型组、高剂量组(给药剂量为2.0 g/kg)、中剂量组(给药剂量为1.0g/kg)、低剂量组(给药剂量为0.5 g/kg)。造模后,对照组和假手术组及模型组均予以蒸馏水灌胃,1次/d,剂量为1 mL/100 g,各剂量组均根据相应剂量的桂枝茯苓胶囊灌胃,1次/d。对比各组大鼠粘连修复相关指标[转化生长因子-β1(TGF-β1)和血管内皮生长因子(VEGF)]、免疫指标[红细胞C3b受体花环率、免疫复合物花环率、免疫球蛋白A(IgA)、IgG、IgM]、TNF-α、IL-2水平及子宫内膜病变情况。结果:造模后,各剂量组、对照组和假手术组红细胞C3b受体花环率、IL-2、IgA、IgG和IgM水平均明显高于模型组,但各剂量组IgA、IgG和IgM水平仍低于对照组和假手术组(均P<0.05);各剂量组、对照组和假手术组免疫复合物花环率、TNF-α、病理综合评分、TGF-β1和VEGF水平均明显低于模型组,但各剂量组病理综合评分、TGF-β1和VEGF水平仍高于对照组和假手术组(均P<0.05)。结论:桂枝茯苓胶囊治疗CPID可能与其抑制炎症水平、促进粘连修复、提升免疫功能有关。  相似文献   

9.
摘要 目的:分析葛根素注射液对糖尿病大鼠牙周炎的治疗效果及血清晚期糖基化终末产物(advanced glycosylation end products,AGEs)、炎性因子表达的影响。方法:随机选取10只大鼠作为正常对照组,另选40只建立糖尿病牙周炎大鼠,将建模成功的大鼠随机分成模型组、实验组和阳性组,每组10只。给药处理6周后,取血清检测AGEs、白细胞介素-6(interleukin-6,IL-6)、IL-8及肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)表达情况;取牙周组织观察压槽骨丧失程度。结果:与健康对照组相比,模型组大鼠胰岛素水平显著降低,血糖、AGEs、IL-6、IL-8和TNF-α水平显著升高,压槽骨降低高度显著增大(P<0.05)。与模型组相比,实验组和阳性组大鼠水平显著升高,血糖、AGEs、IL-6、IL-8和TNF-α水平显著降低,压槽骨降低高度升高减小(P<0.05)。结论:葛根素注射液可通过促进胰岛素表达,减少AGEs积聚,降低血糖及炎性因子IL-6、IL-8、TNF-α的表达抑制糖尿病大鼠牙周炎的发展。  相似文献   

10.
摘要 目的:研究肠内营养(enteral nutrition, EN)联合益生菌对直肠恶性肿瘤术后大鼠肠粘膜屏障及血清炎症因子的影响。方法:选取32只SPF级雄性SD大鼠,随机分对照组、模型组、EN组和EC组,每组8只。模型组、EN组和EC组建立直肠恶性肿瘤术后模型,EN组灌胃给予肠内营养混悬液,EC组灌胃肠内营养混悬液加益生菌颗粒,对照组和模型组灌胃同体积的生理盐水,四组大鼠均连续灌胃7 d。观察各组大鼠小肠超微结构;检测occludin蛋白、D-乳糖及炎症因子的表达水平。结果:模型组大鼠小肠上皮细胞紧密连接和绒毛结构遭破坏,EN组和EC组与模型组相比有明显改善。与对照组相比,模型组大鼠occludin蛋白和抑炎因子IL-10的表达水平均较低,D-乳糖、血清白介素1β(interleukin-1β, IL-1β)和肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)的表达水平较高(P<0.05);与模型组相比,EN组和EC组的occludin蛋白和IL-10的表达水平较高,D-乳糖、IL-1β和TNF-α的表达水平较低(P<0.05);与EN组相比,EC组occludin蛋白和IL-10的表达水平较高,D-乳糖、IL-1β和TNF-α的表达水平较低(P<0.05)。结论:肠内营养联合益生菌可有效改善直肠恶性肿瘤术后大鼠的肠道屏障功能,提高occludin蛋白的表达,降低D-乳糖的表达,降低促炎因子IL-1β和TNF-α的表达同时升高抑炎因子IL-10的表达。  相似文献   

11.
通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.  相似文献   

12.
Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m−2 s−1. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to Pfr.  相似文献   

13.
The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.  相似文献   

14.
15.
A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.  相似文献   

16.
龙胆科药用植物化学成分的研究现状   总被引:16,自引:0,他引:16  
龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。  相似文献   

17.
Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H2-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H2 with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD+, FMN+, and NAD(P)+ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H2OCO2+2H++2e- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation  相似文献   

18.
Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)8 barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)8 structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive ET and active ER. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive ET and active ER represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.  相似文献   

19.
20.
(鱼句)亚科花(鱼骨)型鱼类骨骼系统的比较   总被引:2,自引:0,他引:2  
对我国花型Hemibarbuspattern鱼类作了骨骼系统比较,结果表明,此类型鱼类脑颅较长,副蝶骨平直或稍弯曲,眶蝶骨腹纵嵴发达(铜鱼Coreius septentrionalis例外),下颞窝和咽突中等大,基枕骨后突发达;脑颅中的上筛骨的后突、侧筛骨的外筛突,蝶耳骨的外突、上耳骨的后突、围眶骨和后颞窝等均有明显的差异;咽颅中的舌颌骨、尾舌骨、鳃盖骨和下咽齿的列数等又有显著的区别;附肢骨骼中的腰带骨、脊椎骨中的复合神经骨和第4椎骨腹侧的悬器等也有不同之处。据此,这些差异和区别可作为属间或种间的分类依据。  相似文献   

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