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Interactive analysis of phylogeny and character evolution using the computer program MacClade 总被引:15,自引:0,他引:15
W P Maddison D R Maddison 《Folia primatologica; international journal of primatology》1989,53(1-4):190-202
Computer programs for phylogenetic analysis have been important tools in systematics and evolutionary biology, but most have been designed primarily for the reconstruction of phylogenetic trees and not the interpretation of patterns of character evolution. Described here is the computer program MacClade, designed for interactive analysis of character evolution and phylogeny. For a given tree and a matrix of character data, MacClade displays its reconstruction of character evolution by shading the branches of the tree to indicate ancestral states. Trees can be manipulated for instance by picking up and moving branches. Assumptions underlying the reconstruction of character evolution can be varied extensively. With these manipulations and MacClade's graphical feedback, one can explore the relationships among phylogenetic trees, character data, assumptions and interpretations of character evolution. MacClade has extensive facilities for editing data, displaying various summaries of character evolution in charts and diagrams, and printing. 相似文献
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Fractions and subcellular structures were prepared from rat brain homogenate and their purity was assessed using enzyme markers, gamma-aminobutyric acid binding, DNA content, and electron microscopy. Insulin binding was highest on the plasma membrane preparations and approximately 50% less so on brain homogenate crude mitochondrial (P2), myelinated axon, and synaptosome preparations. Very low levels of binding were found on mitochondria and nuclei. Differences in binding between fractions were due to numbers of binding sites, and not variable binding affinity. There was a close relationship between insulin binding and the activity of Na/K ATPase (E.C. 3.6.1.4) in all fractions (r = 0.98). Insulin binding to the P2 was compared with plasma membrane fractions in seven brain regions, and the results demonstrated the same close relationship between insulin binding and plasma membrane content in all regions except hypothalamus. Plasma membrane insulin binding was well represented by the binding on P2 membranes in all regions except hypothalamus and brainstem. It was concluded that insulin binding is distributed evenly over the surface of brain cells and is not increased on nerve endings. 相似文献
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Isolation and characterization of a large,neurite-associated glycoconjugate from neuroblastoma cells
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A high molecular weight glycoconjugate has been isolated from neurite-producing neuronal tumor cells in culture and has been designated as I(0) based on its elution characteristics in gel filtration chromatography. This molecule cannot be found in a variety of nonneuronal cells. I(0) is found in the substratum-attached material or cell fraction of neurite-producing neuroblastoma cells, depending upon culture conditions. It is found in the substratum-bound fraction of B104 rat neuroblastoma cells during serum starvation and in the EGTA-detached cell fraction of B104 cells grown in chemically defined N2 medium. It occurs only in the cell fraction of the human neuroblastoma line Platt. Examination of behavioral variants of the B104 rat line further strengthens the association of I(0) with neurite production; the constitutive neurite-producing E(R)B9 variant contains I(0) while the non-neurite-producing E(R)A11 variant does not. I(0) is large, eluting in the void volume of sepharose-CL2B columns. Radioiodination of intact cells with lactoperoxidase shows I(0) to be a cell surface component. Metabolic radiolabeling studies show that it contains a high proportion of polysaccharide to protein, does not contain mannose, and is unsulfated. Alkaline borohydride reduction release two size classes of large polysaccharide chain. The alkaline reduction results, along with the mannose incorporation studies, show the presence of O-glycosidic linkages and few, if any, N-linkages. Resistance to nitrous acid deamination, insensitivity to glycosaminoglycan lyases, and the absence of sulfation, indicate that I(0) does not contain the glycosaminoglycans hyaluronic acid, chondroitin-, dermatan-, or heparin- sulfates. Affinity column chromatography reveals high binding affinity of I(0) to polyornithine and no binding to gelatin (collagen) or the glycosaminoglycans hyaluronate and heparin. These studies describe a unique high molecular weight glycoconjugate on the surface of neurite-producing neuroblastoma cell lines from two species. 相似文献
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V C Tsang K R Tsang K Hancock M A Kelly B C Wilson S E Maddison 《Journal of immunology (Baltimore, Md. : 1950)》1983,130(3):1359-1365
A systematic and quantitative search was conducted to identify and isolate a serologically pertinent antigen with high specific activity and low cross-reactivity from adult worms of Schistosoma mansoni. Adult worms of S. mansoni quickly thawed from liquid N2 temperatures were disrupted by controlled homogenization in isotonic buffered sucrose. Differential centrifugation of the homogenate yielded three particulate and one soluble fractions: the 480 x G pellet (nuclear), the 7650 x G pellet (mitochondrial), the 360,000 x G pellet (microsomal), and the 360,000 x G supernatant (cytosol). Quantitative analysis indicated a major concentration of specific antigenic activities in the microsomal fraction. Further purifications of the urea-solubilized, n-butanol-treated microsomal particles by gel filtration and ionic-exchange chromatography resulted in a microsomal antigen (MAMA) possessing high specific activity and low cross-reactivity. The final purification post-ionic exchange chromatograph showed a 30-fold increase of specific antigen activity over that of the cytosol fraction. Sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE) and enzyme-linked immunotransfer blot by the "Western blot" technique (EITB) indicated specific antigenic activities in association with several different m.w. bands (heterogeneous m.w. by extrapolation = 4.3 to 11.9 x 10(6), 2.0 x 10(5), and 2.0 x 10(4) daltons) of the MAMA fraction. When compared with other reported serologic antigens, MAMA showed substantially higher specific activity and lower cross-reactivity. 相似文献
8.
Deep-level diagnostic value of the rDNA-ITS region 总被引:14,自引:0,他引:14
The similarity of certain reported angiosperm rDNA internal transcribed
spacer (ITS) region sequences to those of green algae prompted our analysis
of the deep-level phylogenetic signal in the highly conserved but short
5.8S and hypervariable ITS2 sequences. We found that 5.8S sequences yield
phylogenetic trees similar to but less well supported than those generated
by a ca. 10-fold longer alignment from rDNA-18S sequences, as well as
independent evidence. We attribute this result to our finding that,
compared to 18S, the 5.8S has a higher proportion of sites subject to vary
and greater among-site substitution rate homogeneity. We also determined
that our phylogenetic results are not likely affected by intramolecular
compensatory mutation to maintain RNA secondary structure nor by evident
systematic biases in base composition. Despite historical homology, there
appears to be no ITS2 primary sequence similarity shared sufficient
similarity to cluster correctly on the basis of alignability. Our results
indicate that groups, however, share sufficient similarity to cluster
correctly on the basis of alignability. Our results indicate that ITS
region sequences can diagnose organismal origins and phylogenetic
relationships at many phylogenetic levels and provide a useful paradigm for
molecular evolutionary study.
相似文献
9.
Production of Serine Proteases by the Oyster Pathogen Perkinsus marinus (Apicomplexa) In Vitro 总被引:1,自引:1,他引:0
JEROME F. LA PEYRE DORIS Y. SCHAFHAUSER ESAM H. RIZKALLA MOHAMED FAISAL 《The Journal of eukaryotic microbiology》1995,42(5):544-551
ABSTRACT. Analysis of the cell-free supernatants of Perkinsus marinus cultures by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and silver staining revealed the presence of as many as 17 bands ranging in molecular weight from 239 to 32 kDa. These bands were not present in un-inoculated medium. Moreover, P. marinus produces extracellular proteins that possess proteolytic activities; the cell-free supernatants of P. marinus cultures could digest a variety of proteins including gelatin, casein, fibronectin and laminin. Oyster plasma was also digested by cell-free culture supernatants. The proteolytic activity in cell-free culture supernatants was detected 24 h post-inoculation, while no proteolytic activity could be detected in cell lysates. The proteolytic activities were characterized using substrate-impregnated sodium dodecylsulfate-polyacrylamide gels and had approximate molecular weights ranging from 55 to 35 kDa. The proteolytic activity of cell-free culture supernatants was inhibited by the serine protease inhibitors phenylmethylsulphonyl fluoride, 3,4-dichloroisocoumarin and soybean trypsin inhibitor. In contrast, inhibitors (i.e. trans-epoxysuccinyll-leucylamido(4-guanidino)-butane, 1, 10-phenanthroline, captopril, ethylenediaminetetracetic acid, pepstatin A or diazoacetyl-DL-norleucine methyl ester) from the other three classes of proteases had no effect. It was concluded that the P. marinus proteases in cell-free culture supernatants are serine proteases. 相似文献
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