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1.
本实验对9只蒸汽吸入伤犬在高频喷射通气(HFJV)或高频双向喷射通气(HFTJV)条件下解剖死腔(V_(anat))和生理死腔(V_(phys)的变化进行了观察。结果:①HFJV和HFTJV的CO_2排出量(Vco_2)(4.90±0.65,6.32±1.30ml·min ̄1·kg ̄1)的差异非常显著(P<0.01),②HFTJV的VV_(anat)(76.66±19ml)和V_(phys)(80.87±20ml)比HFJV(分别为88.17±22ml和90.69±22ml)的均显著减少(P<0.05)。③HFJV和HFTJV的功能残气量(FRC)(433±56,444±56ml无显著差异。因此,HFTJV确有加速CO_2排除的效能,其作用应归因于V_(anat),和V_(phys)的减少,它可能成为解决Ⅱ型呼吸衰竭CO_2排除障碍的一种有效途径。  相似文献   

2.
黑曲霉产木聚糖酶发酵条件的研究   总被引:17,自引:0,他引:17  
正交设计试验结果表明,黑曲霉(Aspergillus niger m12)产木聚糖酶活力达76.60u/ml,合适的产酶发酵条件如下,培养基(g/L):麸皮40,尿素6.67,KH2PO4 1.0,MgSO4.7H2O0.5,NaCl0.3,Tween-80 3.0,CaCO3 2.0,28℃,120r/min水浴振荡培养5.5d。  相似文献   

3.
黑曲霉生产β-葡萄糖苷酶发酵条件的研究产   总被引:1,自引:0,他引:1  
经多项式回归分析,研究了不同浓度N 源、C 源、无机盐等对酶产量的影响,确定出最佳培养基配方为:麸皮4 .9 % ,(NH4)2SO4 0 .4 % ,KH2PO4 0 .29 % ,CaCl2 0 .05 % ,MgSO4·7H2O0 .04 % ,FeSO4·7H2 O5mg·L- 1 ,ZnCl2 1 .4mg·L- 1 ,0 .2 % 油酸钠.并对培养温度、时间、培养基初始pH、通气量、接种量、接种方式等培养条件进行优化,使黑曲霉生产β葡萄糖苷酶的产量由17U·ml- 1 增至21 .3U·ml- 1 .  相似文献   

4.
铝对玉米生长和硝酸还原酶活性的影响   总被引:2,自引:0,他引:2  
测定了生长在Al2(SO4)3100μmol/L氮素营养液中的两个玉米品种(SC704和VA35的根系和叶片)的NADH-硝酸还原酶(EC1.6.6.1)和NAD(P)H-硝酸还原酶(EC1.6.6.2)活性。  相似文献   

5.
长果升麻的化学成分研究   总被引:4,自引:0,他引:4  
从长果升麻(Souliea vaginata)根茎中分离出6种皂甙,经光谱(FAB-MS、1H-NMR、1H-1H-COSY、13C-NMR、1H-13C-COSY)分析,分别鉴定为27-deoxyactein(1),actein(2),25-0-乙酰升麻醇木糖甙(3),25-甲基升麻醇木糖甙(4),升麻醇木糖甙(5),24-acetylhydroshengmanol xyloside(6),其中  相似文献   

6.
用奎吖咽(quinacrine)作荧光指标剂,测定玉米(ZeamaysL.)根尖微粒体(MIC)膜囊泡的H~+-泵活性,结果表明1mmol/LNaN_3仅抑制该泵活性约8%,而0.8mmol/L钒酸盐(Van)则可抑制其活性达80%,说明MIC制剂中H~+-泵活性主要由质膜(PM)H~+-ATPase产生。此泵活性严格需要Mg~(2+),二价阳离子作用大小的顺序为Mg~(2+)>Mn~(2+)>Zn~(2+)>Ca~(2+)=0;阴离子作用大小的1顺序为Br~->Cl~->NO_3~->SO_4~(2-),并初步证实当质膜同侧发生电子传递时,没有跨膜H~+梯度(△μH~+)生成。  相似文献   

7.
不同浓度四氯化碳(CCl4)对草鱼肝原代细胞的损伤实验中,CCl4浓度为10μl/ml可引起细胞血清中丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)、乳酸脱氢酶(LDH)逸出量与细胞破损率显著增高,培养液中添加亚硒酸钠(Na2SeO3)0.2μg/ml,则可降低ALT、AST、LDH的逸出量,减轻细胞破损程度。Na2SeO3保护实验中,Na2SeO2+CCl4组预先腹腔注射(ip)0.1mg/kg.bw连续三日,末次ipCCl4混合液1ml/kg.bw,24h内肝组织超氧物歧化酶(SOD)相对活性比CCl4组提高达91.5%,第七日仍提高达54.5%,与对照组的水平基本接近;血清中丙氨酸氨基转氨酶(ALT)水平逐渐降低。本实验还观察到Na2SeO3可引起肝脂质过氧化物显著降低,肝微粒体蛋白含量与细胞色素P—450活性升高;组织切片观察显示肝组织损伤程度减轻,72h后细胞核增多。表明Na2SeO3可提高草鱼肝清除自由基能力,增强肝脏解毒功能。  相似文献   

8.
为研究胃粘膜壁细胞容积致敏感氯通道电流的定位、电生理特征及药物效应并推断其在壁细胞病理生理过程中所起作用,对急性分离的大鼠胃粘膜壁细胞进行全细胞膜片钳记录,将电极液设置为高渗(Δ≈70mOsm),使细胞出现稳定的体积增大后,在其基底膜上记录到容积致敏感氯通道电流(volume-sensitivechloridechannelcurent,VSClCC),该电流具有外向整流性及电压和时间依赖性,可被10μmol/L花生四烯酸(arachidonicacid,AA)可逆性抑制(71.3±10.9%)。细胞外液pH值由7.4降低至4.0,VSClCC的幅度显著下降(63.1±14.0%),而其激活及失活动力学无改变;pH升高至9.0对VSClCC无影响。壁细胞VSClCC对细胞内外钙离子浓度均呈现明显的依赖性。结果表明,壁细胞基底膜上存在本底氯通道和容积致敏感氯通道两种不同的氯离子通道。VSClCC可能参与某些胃粘膜疾病的病理生理过程。  相似文献   

9.
不同钙-醇溶解体系丝素蛋白的制备及表征研究   总被引:1,自引:0,他引:1  
采用 4种中性盐溶液 Ca(NO3)24H2O 甲醇、Ca(NO3)24H2O 乙醇、CaCl2 甲醇 水和 CaCl2 乙醇 水(摩尔比分别为 1∶2、1∶2、1∶2∶8、1∶2∶8)处理蚕丝纤维,透析后经冷冻干燥制成固体,利用SDS PAGE、电镜扫描和红外光谱对制得的固体进行表征。SDS PAGE结果表明:Ca(NO3)24H2O 醇体系降解丝素蛋白较 CaCl2 醇 水体系降解程度高;电镜扫描的结果表明 Ca(NO3)24H2O 甲醇和 CaCl2 乙醇 水溶解体系处理的丝素蛋白溶解比较完全,Ca(NO3)24H2O 甲醇处理的丝素蛋白冻干后为颗粒状,而 CaCl2 乙醇 水处理的丝素蛋白冻干后为片状。红外光谱的结果表明:4种溶液处理后的丝素蛋白构象均介于 β折叠和无规则卷曲之间,从而为丝素蛋白在药物缓释载体领域的应用提供了一定的理论依据。  相似文献   

10.
盐度和CO2倍增环境下碱蓬幼苗呼吸酶活性的变化   总被引:3,自引:0,他引:3  
研究了生长在正常大气CO2和CO2倍增环境中的盐生植物碱蓬(Suaedasalsa)幼苗呼吸酶活性对KCl和NaCl的反应.结果表明,在CO2倍增(700μl·L-1)和正常大气CO2(350μl·L-1)下,300mmol·L-1KCl和NaCl均能抑制琥珀酸脱氢酶(SDH)和苹果酸脱氢酶(MDH)活性,而异柠檬酸脱氢酶(IDH)活性为NaCl抑制、KCl促进;NaCl和KCl明显抑制细胞色素氧化酶(CO)和光呼吸中乙醇酸氧化酶(GO)、羟基丙酮酸还原酶(HPR)活性;并指出在KCl胁迫下,CO2使三羧酸循环(TCAC)的运行变慢,NaCl胁迫下使其加快,TCAC运行限速步骤与MDH无关,CO为盐对呼吸代谢影响的重要位点.另外,K+、Na+对蛋白表达的影响有差异,CO2可使盐胁迫下的碱蓬幼苗蛋白表达降低.  相似文献   

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It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.  相似文献   

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Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.  相似文献   

17.
Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.  相似文献   

18.
肝癌中HBV和HCV基因和抗原的分布及意义   总被引:1,自引:0,他引:1  
采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细  相似文献   

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For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.  相似文献   

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