共查询到20条相似文献,搜索用时 15 毫秒
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从暴发水华的水体分离微囊藻(Microcystis)株,并依据gvpA-C间隔区和16S rDNA序列对其分型和比较。在gvpA-C间隔区序列中,有的类型具有一段172—176 bp的额外序列。以不包括额外序列的0.27 kb序列相比较,不同类型之间差异碱基位点达50余个。在16S rDNA碱基变异集中的0.69 kb序列中,不同类型之间有差异的碱基位点共有8个。与16S rDNA序列相比,微囊藻gvpA-C间隔区序列具有高度变异性,并且其PCR扩增可一步完成,不受其他细菌污染,因而可用于微囊藻株系分型。由于横向转移,2种分型存在交叉关系。此外,原本含有或不含有额外序列的微囊藻gvpA-C间隔区序列在系统进化树中分别聚成一簇。 相似文献
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运用解剖学、组织学方法比较研究西藏高原鳅(Triplophysa tibetana)、细尾高原鳅(Triplophysa stenura)和异尾高原鳅(Triplophysastewarti) 3种高原鳅的消化道结构。结果表明: (1)3种高原鳅的消化道均由口咽腔、食道、胃、肠组成。胃“U”型, 无幽门盲囊, 肠道短, 可分为前、中、后三个部分。异尾高原鳅胃长与消化道长比值最大, 比肠长最短, 为0.51±0.07, 与西藏高原鳅比肠长0.64±0.08和细尾高原鳅比肠长0.70±0.06, 差异显著。(2)异尾高原鳅胃黏膜层相对高度大于西藏高原鳅和细尾高原鳅, 肌肉层相对厚度也比其他2种鱼厚。前肠黏膜层为异尾高原鳅相对高度最大, 肌肉层为西藏高原鳅相对最厚。中肠与后肠黏膜层相对厚度由大到小为异尾高原鳅>细尾高原鳅>西藏高原鳅。综上所述, 3种高原鳅的消化道结构均符合肉食性鱼类特征, 推测异尾高原鳅的结构特征适于消化更多的动物性饵料。 相似文献
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Abstract— Ethyleneglycol-bis (β-aminoethyl ether)-N-N'-tetraacetic acid (EGTA) inhibited the incorporation of 32Pi into phosphatidylinositol (PI) in rat diaphragm incubated in Ca2+-free Krebs-Ringer medium. Only the labelling of the PI was altered, and no effects on the pool size of PI or on the incorporation of 32Pi into other phospholipids were observed. The effect of EGTA was concentration-dependent and appeared to be related to its Caa+-chelating properties; the inhibition of the incorporation of 32Pi could be completely reversed by the addition of excess Ca2+ but not Mg2+. The inhibitory effect of the EGTA was progressively enhanced by lengthening the preincubation of the tissue with EGTA, an observation suggesting that chelation of intracellular or membrane-bound Ca2+, rather than extracellular Ca2+, was involved in the effect. In contrast to its inhibition of the incorporation of 32Pi EGTA enhanced the incorporation of [3H]inositol into PI, but this effect was accompanied by an appreciable increase in total uptake of [3Hlinositol by the tissue. Our results suggest that the level of intracellular Ca2+ plays a role in the regulation of the incorporation of 32Pi into PI. Addition of unlabelled α-glycerophosphate to the incubation medium of tissues which had been preincubated with 2-deoxy-d -glucose failed to cause a significant diminution in the inhibition by EGTA of the incorporation of 32Pi into PI. This experiment suggests, but does not prove, that the effect of EGTA was not at the level of incorporation of 32Pi into α-glycerophosphate. 相似文献
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REVERSAL OF THE CO2 -RESPONSES OF STOMATA BY FUSICOCCIN 总被引:6,自引:5,他引:1
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文章对刀鲚(Coilia nasus)的肌间骨数目、形态、分布特征及组织学结构进行了系统研究。结果表明刀鲚肌间骨的形态种类与普通鲤科鱼类没有显著差别,但其分布类别却有很大不同,刀鲚不仅有髓弓小骨、椎体小骨和脉弓小骨,且在其背部上方和腹部下方仍存在大量肌间骨,这两类肌间骨的形态为简单的"1"形和"("形,分别位于背部上方和腹部下方肌膈的皱褶部;在短颌鲚(C. brachygnathus)背部上方和腹部下方也发现这两类肌间骨的存在,统称为肌骨杆(Myorhabdoi)。刀鲚个体肌间骨数目范围为492—543,其中髓弓小骨为114—142 (■=133),椎体小骨为28—51 (■=42),脉弓小骨为138—153 (■=142),背上肌骨杆为92—135 (=■114),腹下肌骨杆为66—98 (■=89)。采用茜素红与阿利新蓝组织染色观察不同类型肌间骨的组织结构特征,结果显示肌间骨由肌膈结缔组织包被,在髓弓小骨和脉弓小骨两种类型中,肌间骨之间通过结缔组织相互连接。研究在鱼类背上肌骨杆和腹下肌骨杆的发现,是对我国鱼类肌间骨系统进化研究的进一步补充。 相似文献
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P. MALLE M. VALLE P. EB R. TAILLIEZ 《Journal of Rapid Methods and Automation in Microbiology》1998,6(2):129-141
H2 S bacteria of seafish flesh are weakly halophilic and require on average 1.68% NaCl according to statistical studies. Enumeration is optimal on PCA-H2 S(a PCA medium supplemented with sulfur sources and increased NaCl concentrations) incubated at 25C. Total aerobic bacteria can be counted simultaneously on this medium. The proportion of H2 S bacteria relative to total aerobic bacteria increased slightly during prolonged storage of the fish, but was highly variable. Models relating H2 S bacterial counts to spoilage of fish are sigmoidal and showed that when the count exceeds 10,000 CFU/g, whole or filleted fish stored in ice at 0C are unfit for consumption. Shewanella putrefaciens accounted for 69% of the H2 S bacteria at the fifth day of storage and 100% at the fifteenth. 相似文献
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蚤类的幼虫形态,我国迄今已报告15种,其中蚤科Pulicidae 3种,多毛蚤科Hystrichopsyliidae 4种,细蚤科Leptopsyllidae 2种,蝠蚤科Ischnopsyllidae 1种,角叶蚤科Oeratophyllidae 5种。而角叶蚤科的黄鼠蚤属Citellophilus目前已报告2种,即方形黄鼠蚤指名亚种C.t.tesquorum(1961)和三鬃黄鼠蚤巴湖亚种C.trispinus balkhaschensis(叶瑞玉等,1982)。我们在探索方形黄鼠蚤松江亚种C.tesquorum sungaris的生物学特征中,对它的幼虫形态进行了研究,并与同属2个亚种的幼虫形态相比较。 相似文献
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STOMATAL-DEPENDENT AND STOMATAL-INDEPENDENT UPTAKE OF NOx 总被引:2,自引:2,他引:0
HENRIK SAXE 《The New phytologist》1986,103(1):199-205