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1.
The phylogeny of the Piscicolidae was analysed from combined 18S rDNA, cytochrome c oxidase subunit I (CO-I), nicotinamide adenine dinucleotide dehydrogenase subunit I (ND-I) and morphological data using parsimony. A worldwide distribution of Piscicolidae was represented for the first time. While the family Piscicolidae was supported as a monophyletic group, the traditional subfamilies based on morphology were not supported. The Platybdellinae was polyphyletic and formed four distinct clades, and Bathybdella sawyeri did not group with any other platybdellins. The Piscicolinae was also polyphyletic, also forming four distinct clades. The pontobdellin genus Stibarobdella was shown to be the basal taxon within the Piscicolidae; however, the Pontobdellinae was found to be paraphyletic if Oxytonostoma was included. The genera Aestabdella , Austrobdella, and Malmiana were found to be paraphyletic; the genera Calliobdella, Cystobranchus, and Platybdella were found to be polyphyletic. The species Myzobdella lugubris was not found to be monophyletic. It is proposed that Oxytonostoma be transferred out of the Pontobdellinae, that Aestabdella be synonymized with Pterobdella , that Calliobdella vivida be returned to Cystobranchus , that Gonimosobdella be synonymized with Cystobranchus , and that Piscicolaria be synonymized with Myzobdella . The synonymy of Malmiana and Heptacyclus is confirmed, with Heptacyclus having priority. Piscicola milneri is confirmed to be a separate species from Piscicola geometra . 相似文献
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R H Gross 《BioTechniques》1990,8(6):684-689
The Gene Construction Kit is a new tool for manipulating and displaying DNA sequence information. Constructs can be displayed either graphically or as formatted sequence. Segments of DNA can be cut out with restriction enzymes and pasted into other sites. The program keeps track of staggered ends and notifies the user of incompatibilities and offers a choice of ligation options. Each segment of a construct can have its own defined thickness, pattern, direction and color. The sequence listing can be displayed in any font and style in user defined grouping. Nucleotide positions can be displayed as can restriction sites and protein sequences. The DNA can be displayed as either single- or double-stranded. Restriction sites can be readily marked. Alternative views of the DNA can be maintained and the history of the construct automatically stored. Gel electrophoresis patterns can be generated and can be used in cloning project design. Extensive comments can be stored with the construct and can be searched rapidly for key words. High quality illustrations showing multiple editable constructs with added graphics and text information can be generated for slides, posters or publication. 相似文献
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The successful application of a simple flow calorimeter, called the enzyme thermistor, to the specific monitoring of different enzymes in the eluants from some common chromatographic procedures is described. The enzyme thermistor enables a specific enzyme to be continuously determined even in optically dense solutions where spectrophotometric procedures cannot be used. The instrument can be operated either on-line or it can be used for discrete samples. The sensitivity is in the order of 0.1 IU/ml for most enzymes. 相似文献
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Fish bred in tanks or ponds cannot be easily tagged individually. The parentage of any individual may be determined by DNA fingerprinting, but is sufficiently expensive that large numbers cannot be so finger-printed. The measurement of the objective trait can be made on a much larger sample relatively cheaply. This article deals with experimental designs for selecting individuals to be finger-printed and for the estimation of the individual and family breeding values. The general setup provides estimates for both genetic effects regarded as fixed or random and for fixed effects due to known regressors. The family effects can be well estimated when even very small numbers are finger-printed, provided that they are the individuals with the most extreme phenotypes. 相似文献
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Cathepsin B (EC 3.4.22.1) from buffalo spleen was isolated to homogeneity and its molecular weight was determined to be 25 KDa. The enzyme was found to be a glycoprotein having a total carbohydrate content of 7%. The NH2- and COOH-terminal amino acid residues were identified as Leu and Thr, respectively. The specific extinction coefficient, E1%1cm, of the enzyme was determined to be 13.2. The value of intrinsic viscosity and equivalent hydrodynamic radius of the enzyme were calculated to be 3.47 ml/gm and 2.34 nm, respectively. Polyclonal antibodies raised in rabbits were found to cross-react distinctly with the purified buffalo enzyme. Using BANA as substrate, the Km and Vmax values were determined to be 0.93 mM and 5.57 Units/mg, respectively. The buffalo enzyme was also found to be highly active against protein substrates, and the Km values for casein and BSA were measured to be 1.12 and 1.74 microM, respectively. 相似文献
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The progress and changes in management of tuberculosis are extensive and dramatic. Chemotherapy now leads the list of methods, and combinations of drugs containing isoniazid are the most effective. The use of such drugs in chemoprophylaxis has a new and expanding basis of value.The other methods of therapy are considered to be adjunctive. Among them, pulmonary resection is of greatest value, although needed less often. Rest may be less complete than once was prescribed, and of shorter duration; exercise may be prescribed sooner and be more vigorous.Rehabilitation is a part of treatment. It may be physical, mental, and social restoration or training. It may often be initiated in the early phases of treatment. The methods depend on the individual, the objective, and the pulmonary disease. 相似文献
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我们抢救成活1例因服100片速可眠致重度昏迷、呼吸停止54小时的女青年,体会如下:①必须迅速彻底洗胃。②自主呼吸停止时,应立即气管插管。③要适当应用中枢兴奋剂,有利于争取时间进行综合治疗。④要适当应用脱水剂并用利尿剂,以控制脑水肿。⑤必须严格执行昏迷护理常规,维持水电解质平衡,预防合并症。 相似文献
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Lewis Grodsky 《The Western journal of medicine》1967,106(1):44-48
The unsatisfactory results of radical operations in advanced anal cancer could be bettered by earlier diagnosis of the malignant lesion. The possibility of cancer should always be kept in mind when treating any of the common chronic anal diseases. Preliminary biopsy studies should be done more frequently if suspicious lesions are present and all tissues removed during minor anorectal operations should always be examined by a pathologist. Each surgical specimen should be labeled to show the site from which it was removed. Follow-up care of the patient would be simplified if the exact site of cancer origin could be identified.A recent ten-year survey of minor anorectal surgical procedures at the University of California Medical Center showed clinically unsuspected anal cancer found in 2 per cent of cases on tissue examination by the pathologist. The cancers were generally early and of the keratinizing squamous cell and nonkeratinizing varieties. 相似文献
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The results of recent spectroscopic measurements on chlorophyll a in bilayers and lipid vesicles stimulated a re-examination of energy transfer in photosynthesis. The Förster resonance transfer mechanism is believed to be applicable under reasonable assumptions despite recent criticism. The Förster parameter was newly determined to be R0 = 65 Å; previous uncertainty due to unknown transition moment orientation can be avoided by assuming the black film dichroic result to be applicable in vivo. The effect due to the still incompletely known thylakoid structure and chlorophyll aggregation is discussed qualitatively. Agreement with experimental fluorescence lifetimes and quantum efficiencies may be obtained with a reasonable choice of parameters. 相似文献
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Liu Q Huang Q Teng M Weeks CM Jelsch C Zhang R Niu L 《The Journal of biological chemistry》2003,278(42):41400-41408
The crystal structure of acutohaemolysin, a lysine 49 phospholipase A2 protein with 1010 non-hydrogen protein atoms and 232 water molecules, has been determined ab initio using the program SnB at an ultrahigh resolution of 0.8 A. The lack of catalytic activity appears to be related to the presence of Phe102, which prevents the access of substrate to the active site. The substitution of tryptophan for leucine at residue 10 interferes with dimer formation and may be responsible for the additional loss of hemolytic activity. The ultrahigh resolution of the experimental diffraction data permits alternative conformations to be modeled for disordered residues, many hydrogen atoms to be located, the protonation of the Nepsilon2 atom in the catalytic residue His48 to be observed experimentally, and the density of the bonding electrons to be analyzed in detail. 相似文献
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中国蕨科的数量分类研究 总被引:5,自引:0,他引:5
本文用聚类分析的方法,对中国蕨科23个种代表9个属做了数量分类研究,通过23OTUs×37个性状的原始数值矩阵标准化后,用欧氏距离系数计算相似性,采用WPGMA法进行聚类分析,以探索各属之间的系统位置和亲缘关系。其结果与我国植物学家经典分类处理基本上一致,并对粉背蕨属(Aleuritopteris)也做了修正,认为粉背蕨系(Ser.Farinosae)和银粉背蕨系(Sef.Argenteae)也可做为两个新属处理比较合理。另外对距离系数和结合线在类群划分申的作用进行了讨论和评价。 相似文献
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蛾螺科三种螺的核型观察 总被引:5,自引:0,他引:5
本文介绍了蛾螺科三种螺的核型。水泡蛾螺(Buccinum pcmphigum)为2n=30,染色体的形态分类组成为16m+10sm+4st,NF=56;Plicifusus scissuratus为2n=34,染色体的形态分类组成为20m+10sm+4st,NF=64;香螺(Neptumea cumingi)为2n=60,染色体的形态分类组成为30m+22sm+8st,NF=112。 蛾螺科核型分析,显示贝类染色体数目及其形态与贝类进化有关。 相似文献
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A behavior or strategy which is evolutionarily stable must be both optimal and stable. The strategy must be optimal in that it maximizes the expected fitness of all the individuals using it. In addition, the strategy must be resistant to invasion by a mutant. The difference between the Nash solution of game theory and the ESS used in ecology is that the Nash solution only satisfies an optimality criterion and not an evolutionary stability criterion. We extend the ESS definition of Maynard Smith and Price so that it can be applied directly to two-strategy evolutionary games. The concept of a balanced game is introduced, and necessary conditions are derived which are similar to the Nash necessary conditions. The balanced game necessary conditions may be used for direct calculation of ESS candidates. These results are used to examine the optimal flowering time of an annual plant experiencing competition from neighboring plants. The plant competition model is general, and the results may be applied to a wide range of interference competition problems. 相似文献
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The most critical point for the biosafety is not sophisticated devices or facilities, but education of workers and their compliance to the regulation. Appropriate devices should be carefully selected in the introduction of new devices, and they should be properly maintained. The class II biosafety cabinet is one of the delicate safety equipments. It should be kept adequately maintained throughout the lifetime of the cabinet to insure safety of the laboratory. For the maintenance, appropriate measuring equipments should be used by trained technicians. The recently enforced law for control of recombinant DNA researches should be applied for the handling of pathogens even in non-recombinant DNA researches after proper modifications. 相似文献
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Sections of mitochondria in Paramecium and Euplotes present a consistent pattern. The mitochondrion in these cells can be conceived of as a twisted mass of closely compacted tubules. Two general kinds of substances can be recognized: the electron-dense that borders the lumen of the tubule, and the less dense that forms the continuum. In sections of mitochondria in rat kidney and snail oviduct, tubular internal organization can be recognized. In the same organs, mitochondria with lamellar internal structure can be demonstrated. The thesis is developed that the mitochondrion is a structure capable of differentiation and change, and that developmental continuity among the different kinds may exist. Mitochondria that appear to be different may be quite similar basically; mitochondria that appear to be similar in structure may be different in other ways. The tubule is proposed as the most basic of the presently recognized mitochondrial structures. 相似文献
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Asymmetric ultrafiltration membranes suitable for covalent bonding of urease can be prepared from membranes based upon polyamide or polysulfone. Because the original membrane polymers are not chemically reactive, they have to be converted in such a way that known reactions for enzyme fixation can be used such as the diazo, the acyl-acid, the carbodiimide, and the methylbromide reaction. The enzyme was fixed within the porous substructure of the membrane. The amount of enzyme immobilized at the membrane dense skin was found to be negligible. The kinetics can be described according to the Michaelis-Menten model. Compared to the native urease, the activity of the membrane-bonded enzyme was very low. The reasons can be sought in the transmembrane transport and in the fixation procedure as well. 相似文献
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我们利用微型计算机图形技术对两种铁氧还蛋白的分子结构进行了研究,输入蛋白晶体数据,重构出铁氧还蛋白分子的三维结构模型,并可使之统X轴、Y轴和Z轴旋转;计算出肽链上原子之间的健长、健角、(?)角:显示微区结构;进一步可使两个铁氧还蛋白的三维结构图叠合,(?)利比较分析.实验表明,微型计算机分子图开技术在研究蛋白质等生物大分子结构,运动及中与功能的关系方面是有效的工具; 相似文献