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1.
封面说明     
帝企鹅 Aptenodytes forsteri 鸟纲、企鹅总目、企鹅科。分布于南极等处。体型大,直立时高达1m,平均体重约30kg。腹部羽色与其他种不同,胸腹部呈淡柠檬黄色。前肢特化成鳍状,善于划水,无飞翔能力。羽成鳞片状。腿短且移于体后,趾间具蹼.骨骼沉重而不充气,皮  相似文献   

2.
秃鹫骨骼的解剖学特点   总被引:4,自引:0,他引:4  
对秃鹫(aegypius monachus)骨骼进行了详细的观察、描述和功能分析.结果表明,其头骨较宽;上喙粗长、前端近垂直下弯;前额骨游离,眶突发达;龙骨突不发达;叉骨呈"U"形,叉骨头膨大、具发达的叉骨,乌喙骨关节面;前肢骨明显长于后肢骨;第一掌骨伸肌突发达;跗跖骨前后宽扁,跗后跟嵴短;足部近端趾节略长于远端趾节.这些特征与秃鹫的取食方法与偏好及飞行与栖息特点密切相关.  相似文献   

3.
黄线狭鳕骨骼的研究   总被引:5,自引:0,他引:5  
本文记述黄线狭鳕骨骼系统的结构,有以下特点:鼻骨发达,背面形成一深沟;额骨,翼耳骨,前鳃盖骨和围眶骨有发达的感觉管;额骨上有囟门,泪骨很发达,耳石特大;下鳃盖骨特别肥厚,后匙骨上端亦很肥厚,呈槌状。  相似文献   

4.
金鱼藻营养器官的形态解剖学研究   总被引:1,自引:0,他引:1  
通过对金鱼藻最常见的营养器官茎和叶的形态解剖观察发现:整个植株脆性较大;茎中通气组织不发达,木质部和机械组织不发达,凯氏带不明显;叶片薄而透明,二歧状分枝,表皮含大量的叶绿体,通气组织特别发达,气腔有端壁且有通道相连,木质部退化.  相似文献   

5.
本文记述黄线狭鳕骨骼系统的结构。有以下特点:鼻骨发达,背面形成一深沟;额骨、翼耳骨、前鳃盖骨和围眶骨有发达的感觉管;额骨上有囱门;泪骨很发达;耳石特大;下鳃盖骨特别肥厚;后匙骨上端亦很肥厚,呈槌状。  相似文献   

6.
运用形态解剖和组织学方法对宽体沙鳅消化系统进行了研究.宽体沙鳅的胃呈U形;消化道较短,为体长的1.02±0.05倍.咽部粘膜层味蕾发达;未见食道纵肌层;胃分贲门部、盲囊部和幽门部,贲门部具胃腺,盲囊部环肌层发达,幽门部肌肉层3层,呈纵-环-纵排列,幽门括约肌发达;肠各段组织结构无明显差异;肝脏2叶,左叶发达;胰腺组织弥散在肝、脾、胃、肠等的系膜上或随血管的分支进入肝脏组织内.  相似文献   

7.
本文记述采自云南的鲤科鱼类一新种。Sauvage(1878)以上下唇具乳突等特征建立了方口鲃属Cosmochilus,迄今共3个种。新种命名为南腊方口鲃C.nanlaensis sp.nov.以乳突不发达、呈绒毛状;第一鳃弓鳃耙稀疏;上颌须呈退化状,口角须亦不发达;背鳍末根不分枝鳍条较短;侧线鳞数目偏少等特征易与本属其他种类相区别。文末附本属鱼类之检索表。  相似文献   

8.
根据1984—2017年上海动物园圈养斑嘴环企鹅Spheniscus demersus数据,应用Sparks 1.6和PMx 1.0进行数据整理、统计学和遗传学分析。结果显示,该种群数量呈增长状态,但也存在如下问题:(1)种群中未知性别比例过高,占46.25%;(2)种群年龄结构不合理,0~4岁及7~8岁个体数量不足,育龄个体中未知性别的数量较多;(3)雌雄个体0~1岁、10~13岁的死亡率偏高,曲霉菌病是致死的主要原因;(4)参与繁殖的奠基者数量(9只)和潜在奠基者数量(1只)少,分属2个家系,且后代数和贡献值明显不均衡,种群的平均亲缘关系值为0.097 2,种群的平均近亲繁殖系数为0.099 5,存在近亲繁殖现象;(5)虽然现有种群保留了野生个体90.28%的基因多样性,但未来丢失也较快。因此,为了建立健康的斑嘴环企鹅种群,应尽快引进新的血统,开展性别鉴定工作,采取预防为主、防治结合的方式降低曲霉菌病的致病率;采用各种技术如人工授精技术提高企鹅受精率,为繁殖个体,尤其是后代数量过少的奠基者个体提供均等的繁殖机会,从而加强上海动物园圈养斑嘴环企鹅的种群管理。  相似文献   

9.
本实验用氚标记环磷酸腺苷(~3H-cAMP)及碘标记环一磷酸鸟苷(I~(125)-cAGP)的放射免疫法,测定了体外培养S_(180)-V系细胞周期中悬浮的M期细胞和其贴瓶细胞与均相细胞内cAMP及cGMP的含量,并对相应的细胞形态的变化做了扫描电镜观察。此外,对这三种群体细胞体积进行了测量,据此对这些细胞内cAMP及cGMP浓度进行了换算。实验结果表明:M期细胞体积的平均值接近其它时相细胞平均细胞体积的2倍,M期细胞的cAMP含量明显低于贴瓶细胞和均相细胞内cAMP含量,而cGMP含量略有提高,但差异不显著,但cAMP/cGMP比值与贴瓶细胞(非M期的其它时相细胞)及均相细胞(包括M期时相的混合细胞)相比,显著降低,相差2—3倍。用扫描电镜对上述测定的各类细胞组份进行了对应的观察,从其外形的变化表明,S_(180)-V系细胞的骨架系统很不发达,在cANP含量低的漂浮组(M期细胞)比贴瓶细胞的骨骼系统更不发达.  相似文献   

10.
蛇雕消化系统形态学研究   总被引:10,自引:5,他引:5  
对蛇雕消化系统进行了解剖观察,结果表明:蛇雕有锋利的喙,利于撕裂食物;舌根表面具有尖端指向后方的栉状突,可防止食物滑脱;粗大且收缩性较大的食管,嗉囊发达,肌胃不太发达,相对于体长而言肠管较短,但小肠较发达,具有不发达的双侧盲肠。并与部分食植物的鸟类作了比较。  相似文献   

11.
Genes encoding phytochelatin (PC) synthase have been found in higher plants, fission yeast and worm. Recently, kinetic and mutagenic analyses of recombinant PC synthase have been revealing the molecular mechanisms underlying PC synthesis, however, a conclusive model has not been established. To clarify the mechanism of PC synthase found in eukaryotes, we have compared the two-step reactions catalyzed by the prokaryotic Nostoc PC synthase (NsPCS) and the eukaryotic Arabidopsis PC synthase (AtPCS1). Comparative analysis shows that in the first step of PC synthesis corresponding to the cleavage of -glutamylcysteine (-EC) from glutathione (GSH), free GSH or PCs acts as a donor molecule to supply a -EC unit for elongation of the PC chain, and heavy metal ions are required to carry out the cleavage. Furthermore, functional analyses of various mutants of NsPCS and AtPCS1, selected by comparing the sequences of NsPCS and AtPCS1, indicate that the N-terminal region (residues 1–221) in AtPCS1 is the catalytic domain, and in this region, the Cys56 residue is associated with the PC synthesis reaction. These results enable us to propose an advanced model of PC synthesis, describing substrate specificity, heavy metal requirement, and the active site in the enzyme.  相似文献   

12.
Cytoplasmic expression of complex eukaryotic proteins inEscherichia coli usually yields inactive protein preparations. In some cases, (part) of the biological activity can be recovered by rather inefficient denaturation-renaturation procedures. Recently, novel concepts have been developed for the expression of fully functional eukaryotic proteins inE. coli. Essential to the success of these procedures is the transport of such proteins across the inner membrane to the periplasmic space, allowing proper folding and the establishment of disulfide bonding. Subsequently, fully functional proteins can be exposed on the surface of filamentous (bacterio)phages, provided a system is employed that consists of a cloning vector (e.g. the phagemid pComb3, Barbas et al., 1991) that generates phage particles in the presence of a helper phage. The main advantage of surface display of recombinant proteins is to facilitate the screening of very large numbers of different molecules by simple selection methods (panning). In addition, periplasmic expression yields relatively large quantities (e.g. 1 mg l–1 of culture) soluble protein. In this review, the principle aspects of this novel expression system based on the phagemid pComb3 will be discussed. Two examples for functional periplasmic expression of human proteins inE. coli will be presented, namely i) the antigen-binding moiety (Fab fragment) of human immunoglobulins (IgGs) and ii) the human plasminogen activator inhibitor 1, an essential regulator of the plasminogen activation system. Finally, perspectives for the application of this system to express mutant proteins, fragments of proteins and peptides are indicated.Abbreviations ApR ampicillin resistance - cfu colony forming unit(s) - cpIII gene III-encoded coat protein of M13 - cpVIII gene VIII-encoded coat protein of M13 - ER endoplasmic reticulum - Fab fragment of Ig containing light chain, variable region and first constant region of heavy chain - Fd variable region and first constant region of the heavy chain - Fv fragment containing variable regions of heavy and light chain - Ig immunoglobulin - KmR kanamycin resistance - kb kilobase or 1000 basepairs - PAI-1 plasminogen activator inhibitor 1 - t-PA tissue-type plasminogen activator - u-PA urokinase-type plasminogen activator  相似文献   

13.
Highly metal-polluted (Pb, Cd, Zn) soil from a non-ferrous mine and smelter site in southern Poland, further referred to as Waryski soil, was used to test indigenous plant species for stabilization effectiveness of heavy metals in soils. Results of pilot investigations with commercially available cultivars of plant species showed that these cultivars could not grow on this highly polluted soil even with the application of soil amendments to stabilize the heavy metals. Based on these results, mesocosm and field experiments with an indigenous, metal-tolerant ecotype of Deschampsia cespitosa from the Waryñski site were carried out. The mesocosm experiment showed that applications of calcium phosphate (3.8% w/w) as a heavy metal-stabilizing amendment decreased Cd and Zn concentrations 2 and 3-fold respectively in leachates, whereas lead content was not significantly changed. This decrease in the concentration of heavy metals in leachates was correlated with a lower accumulation of Pb, Cd and Zn in the roots and shoots of D. cespitosa, ecotype Waryñski. In the field experiment, lower accumulations of Cd in roots and shoots and Zn in shoots in the amendment added plot were observed during the second year of investigations. In the first growing season, D. cespitosa plant cover in the amendment enriched mesocosms ranged from 95 to 100%, compared to 10% in mesocosms without calcium phosphate. In the second year of the experiment, in non-amendment enriched mesocosms D. cespitosa was substituted with Cardaminopsis arenosa(95% cover). C. arenosa is an undesirable species for phytostabilization, as it accumulates high amounts of zinc and cadmium in its shoots, even thought it provided better growth cover in not amended soils. However, in amended mesocosms, soil surface cover by D. cespitosa was still very high (90%). Similar results were obtained in field experiments. Addition of calcium phosphate to the soil also resulted in excellent D. cespitosa root system development when compared to soils without amendment. In amended mesocosms, high plant cover and root system development significantly decreased the volume of leachates and improved water retention. These results indicate that the use of D. cespitosa, ecotype Waryski in combination with calcium phosphate as a heavy metals immobilizing agent is sufficient to restore a dense vegetative cover to highly heavy metal-polluted soil.  相似文献   

14.
By means of sucrose density centrifugation three membrane fractions, named light, medium and heavy have been isolated from cells of Rhodopseudomonas capsulata strain 37b4, adapting from chemotrophic to phototrophic growth conditions. Succinate dehydrogenase activity of aerobically grown cells was mainly confined to the heavy (chromatophore) fraction. Upon changing to phototrophic conditions the activity of the succinate dehydrogenase increased in the medium and light fraction. All fractions contain bacteriochlorophyll. NADH dehydrogenase of chemotrophically grown cells was enriched in the light and medium fraction but is increased in the heavy fraction under phototrophic growth conditions. The capacity of photophosphorylation is high in the light and heavy fraction. The results indicate a differentially incorporation of functional subunits into specific parts of the membrane system during membrane differentiation.Abbreviations Bchl bacteriochlorophyll - CCCP carbonyl cyanide m-chlorophenyl hydrazone - DCCD N,N-dicyclohexyl carbodiimide  相似文献   

15.
Summary Clathrin-coated vesicles have been isolated from cotyledons of both developing and germinating pea seeds using differential centrifugation, ribonuclease treatment, discontinuous sucrose gradients, and isopycnic centrifugation on a linear D2O-Ficoll gradient. The yield of coated vesicles from developing pea cotyledons was exceptional, being 1.6 × higher than the yield from hog and bovine brain, 5.3 × higher than the yield from carrot suspension cultures, and 13 × the yield from cotyledons of germinating pea seeds. The pea coated vesicles are similar to other plant coated vesicles in size (approximately 80 nm in diameter) and in having a clathrin heavy chain of 190,000 Mr. The lipid phosphorus to protein ratio, 190–250 nmol P per mg protein, of the coated vesicles from plants is comparable to that reported for highly purified coated vesicles from animals. The nondenatured pea clathrin reacted weakly with an antiserum to bovine brain clathrin, but pea clathrin denatured by sodium dodecyl sulfate did not.Abbreviations CLC Clathrin light chain - CHC clathrin heavy chain - CV coated vesicle - DTT dithiothreitol - EGTA ethyleneglycol-bis-(-aminoethyl ether) N,N-tetraacetic acid - SDS-PAGE sodium dodecyl sulfate polyacrylamide gel electrophoresis - TBS Tris buffered saline  相似文献   

16.
Greenhouse experiments were conducted to evaluate the impact of red mud, the residue of the Bayer process for extracting alumina from bauxite, on wetland to investigate whether red mud can be used for wetland restoration. Two wetland species,Spartina alterniflora Loisel. andSagittaria lancifolia L., were used to test their response to the following substrate treatments: 100% marsh sediment, 100% red mud, a mixture of 50% marsh sediment and 50% red mud, a mixture of 50% red mud and 50% compost, and neutralized red mud. Each substrate treatment received two fertilization levels, fertilized (N–P–K) and unfertilized. Red mud could support the growth of the salt marsh species,Spartina alterniflora, but not the fresh marsh species.Sagittaria lancifolia. The high Na content and salinity of red mud, even when mixed with marsh sediment or compost, appeared to be the primary cause for the high mortality ofSagittaria in these substrates. Fertilization did not reduce the stress response ofSagittaria to red mud, but significantly increased the growth ofSpartina. Red mud is low in available N and P and required fertilizer or organic matter (e.g., compost) addition to increase fertility. In experiments with both fresh and salt marsh sediments, the concentrations of soluble heavy metals, with the exception of Mn, were not significantly greater for red mud than for marsh sediment. Thus, the release of heavy metals from red mud over the short-term may not pose an environmental concern. However, the mobilization of heavy metals over the long-term and the influence of plants in accumulating metals requires further investigation.  相似文献   

17.
Summary AllAspergillus nidulans 5S rRNA pseudogenes known so far are the result of integration of an approx. 0.2-kbp-long DNA sequence into the 5S rRNA genes. This sequence, called block C, is present in at least five copies in theA. nidulans genome and seems to be associated either with 5S rRNA genes or pseudogenes. In contrast to the 78% sequence conservation of the C-block in pseudogenes, the truncated 5 halves of the pseudogenes are very highly conserved (96.9–100%). We postulate that the 5S rRNA pseudogenes are still a subject of concerted evolution. The C-block sequence shows similarity to the switch region of the mouse heavy chain immunoglobulin gene. A characteristic motif GGGTGAG is repeated several times in both sequences; the sequence conservation is 63%.  相似文献   

18.
Yang  Jing-Rong  Duthie  Hamish C. 《Hydrobiologia》1993,269(1):57-66
Teratological forms of Stephanodiscus niagarae Ehrenb. and S. parvus Stoermer & Håkansson were observed during a study of diatoms preserved in a radiometrically dated core from Hamilton Harbour (Lake Ontario, Canada). Morphological features and ultrastructures of both species were studied under the light and scanning electron microscope. The valve structure of abnormal forms of S. niagarae appears to be weakly silicified, especially in the central area. The shape of satellite pores are very irregular in comparison with the round shape of the normal specimen. The central fultoportulae are characterized as small tubes extending out of the external valve. Two types of abnormal frustules are present in the population of S. parvus studied. In one type valves are underdeveloped and only the siliceous layer and ribs are present, and in the other type the valves are strongly silicified and the areolae are almost completely occluded.The teratological forms of both species appeared in the core sediments after 1911, and both became the dominant components of diatom assemblages after 1970. Their occurrence and increased abundance coincides with records of heavy metal pollution in the harbour.  相似文献   

19.
Combination of genetic systems of degradation of polyaromatic hydrocarbons, resistance to heavy metals, and promotion of plant growth/protection is one of the approaches to the creation of polyfunctional strains for phytoremediation of soils after co-contamination with organic pollutants and heavy metals. A plant-growth-promoting rhizosphere strain Pseudomonas chlororaphis PCL1391 (pBS216*, pBS501) has been obtained, in which the nah operon of plasmid pBS216 provides naphthalene biodegradation and the cnr-like operon of plasmid pBS501 provides resistance to cobalt and nickel due to the extrusion of heavy metal cations from the cells. In the presence of 100 μM of nickel, the viability, growth rate, and naphthalene biodegradation efficiency of the resistant strain PCL1391 (pBS216*, pBS501) were much higher as compared with the sensitive PCL1391 (pBS216). During the growth of the resistant strain, in contrast to the sensitive strain, nickel (100 μM) had no inhibiting effect on the activity of the key enzymes of naphthalene biodegradation. Original Russian Text ? T.V. Siunova, T.O. Anokhina, A.V. Mashukova, V.V. Kochetkov, A.M. Boronin, 2007, published in Mikrobiologiya, 2007, Vol. 76, No. 2, pp. 212–218.  相似文献   

20.
Complementary DNAs of two kinesin-related genes,katB andkatC, were isolated fromArabidopsis thaliana and sequenced. The carboxyl-terminal regions of the polypeptides encoded by these genes, especially the presumptive ATP-binding and microtubule-binding domains, share significant sequence homology with the mechanochemical motor domain of the kinesin heavy chain. The predicted secondary structures of KatB and KatC proteins include a large globular domain in the carboxyl-terminal region and a small globular domain in the amino-terminal region that are separated by a long -helical coiled-coil with heptad repeats. A truncated KatC polypeptide (KatC(207–754)), which includes the carboxylterminal region of KatC, was expressed inEscherichia coli and was shown to possess microtubule-stimulated ATPase activity and to bind to microtubules in an ATP-sensitive manner, both of which are characteristics of kinesin and kinesin-like proteins.  相似文献   

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