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1.
We have isolated the delta-globin gene of the New-World spider monkey,
Ateles geoffroyi, and compared its nucleotide sequence with those of other
primate delta- and beta-globin genes. Among primate delta-globin genes, the
rate of nonsynonymous substitutions is much less than the rate of
synonymous substitutions. This suggests that primate delta- globin genes
may remain under evolutionary conservation, perhaps because hemoglobin A2
has an as yet unknown physiological importance.
相似文献
2.
Total cellular fatty acids for 20 strains of Erwinia amylovora grown on trypticase soy agar (TSA) for 3 days at 27°C, and for 3 strains grown on nutrient agar (NA), King's B (KB), glucoseyeast extract carbonate (GYCA) and TSA for 1, 3 and 6 days were analyzed by gas-liquid chromatography. Forty one percent of total fatty acids were saturated even-carbon straight chains, 6 % were saturated odd-carbon chains, 34 % unsaturated acids, 6 % hydroxy-substituted acids, 1 % branched chains, 7 % cyclic acids, and 4 % unidentified components. Composition was affected by growth medium, physiological age of cells, and chromatograph sensitivity. On TSA and NA saturated odd-carbon and cyclic acids of the 3 strains (combining 1, 3 and 6-day data) were higher than on KB and GYCA. Cyclic acids increased with physiological age on GYCA and KB medium. Even-carbon straight chain and unsaturated fatty acids (major components) constituted a significantly lower percentage of total fatty acids in chromatograms of high sensitivity (30–50 components) than of low instrument sensitivity (15–20 components). 相似文献
3.
Biochemical pathways in prokaryotes can be traced backward through evolutionary time 总被引:10,自引:0,他引:10
For the first time, a credible prokaryotic phylogenetic tree is being
assembled by Woese and others using quantitative sequence analysis of
oligonucleotides in the highly conservative rRNA. This provides an
evolutionary scale against which the evolutionary steps that led to the
arrangement and regulation of contemporary biochemical pathways can be
measured. This paper presents an emerging evolutionary picture of aromatic
amino acid biosynthesis within a large superfamily assemblage of
prokaryotes that is sufficiently developed to illustrate a new perspective
that will be applicable to many other biochemical pathways.
相似文献
4.
In Drosophila pseudoobscura, the amylase (Amy) multigene family is
contained within a series of inversions, or gene arrangements, on the third
chromosome. The Standard (ST), Santa Cruz (SC), and Tree Line (TL)
inversions are central to the phylogeny of arrangements, and have clusters
of other arrangements derived from them. The gene arrangements belonging to
each of these three clusters have a characteristic number of Amy genes,
ranging from three in ST to two in SC to one in TL. This distribution
pattern can reflect a history of either duplications or deletions, although
the data available in the past did not permit a decision between these
alternatives. We provide unambiguous evidence that three Amy genes were
present before the divergence of the ST, SC, and TL arrangements. Thus, the
current status of the Amy multigene family is the result of deletions in
the TL and SC arrangements, which created three new pseudogenes: TL
Amy2-psi, TL Amy3-psi, and SC Amy3- psi. Analysis of pseudogene sequences
revealed that, in the SC and ST arrangements, pseudogene evolution has been
retarded, most likely due to the homogenization effect of gene conversion.
Finally, by determining the original copy number, we have reconstructed the
evolutionary history of the Amy multigene family and linked it with the
evolution of the central gene arrangements.
相似文献
5.
Hydroxyl Radicals and a Thylakoid-Bound Endopeptidase are Involved in Light- and Oxygen-Induced Proteolysis in Oat Chloroplasts 总被引:4,自引:0,他引:4
Casano Leonardo M.; Lascano H. Ramiro; Trippi Victorio S. 《Plant & cell physiology》1994,35(2):145-152
The hypothesis that light- and oxygen-induced proteolysis inchloroplasts is mediated by active oxygen species was examined.In order to determine whether or not H2O2 and/or {dot}OH radicalsare involved in these degradative processes we compared thedegradation of proteins in isolated oat chloroplasts exposedto white light at 80 W m-2 with that in chloroplasts incubatedin darkness in the absence or presence of H2O2 or a {dot}OH-generatingsystem composed by ascorbic acid, FeCl3 and H2O2 (Asc-Fe-H2O2).Light enhanced the rate of degradation of at least 18 polypeptides,while proteolysis was almost negligible in darkness in the abscenceof additives. H2O2 had a very small effect. However, Asc-Fe-H2O2-treatedchloroplasts in darkness showed a pattern of protein degradationalmost identical to that observed in the light. A thylakoid-boundendopeptidase (EP), the activity of which increased under photooxidativeenvironmental conditions and treatment with an {dot}OH-generatingsystem, was partially purified and characterized as a serinetypeprotease. Treatments with inhibitors of serine-type proteaseprevented both light- and Asc- Fe-H2O2-induced proteolysis.EP was more active against both soluble and membranous proteinsthat had been pretreated with Asc-Fe-H2O2 than against untreatedproteins. It is proposed that a high dose of light irradiationpromotes proteolysis by increasing the formation of {dot}OH,which may modify proteins such that they become more susceptibleto EP-catalyzed hydrolysis.
1Fisiología Vegetal, Dept. de Biología Vegetal,Universidad de Alcalá de Henares, Present address: 28871Alcalá de Henares (Madrid), España. 相似文献
6.
The application of sensory methodology for measuring deodorizing effect of an air conditioner equipped with electric plasma was introduced. Deodorizing effect was measured using chemical and sensory methods at different time (0, 30 and 60 min) and mode (control, blowing and cooling) of an air conditioner. Smoke from a roll of cigarette in a closed room was used as a source of odor and the concentrations of acetic acid and ammonia were measured as odorous chemical components. As one of the sensory methods triangle test was used and as a first step to obtain deodorizing effects by triangle test, the threshold of each panelist was obtained as the log dilution ratio of odor concentration at which the difference from odorless air was detected. The odor concentration at each time and mode was calculated using the threshold of the panel and the deodorizing effect was obtained on the basis of the odor concentration. In addition to a triangle test, scaling methods such as category scaling or magnitude estimation were used to measure deodorizing effect of an air conditioner. Deodorizing effects by scaling methods were calculated based on odor intensity with time at each mode. The regression analysis was done between the efficacy of deodorizing effect by sensory test and those by acetic acid and ammonia, the R2 values of the regression equations for triangle test, category scale, and magnitude estimation were 0.84, 0.72 and 0.69, respectively. Deodorizing effect by triangle test explained the decrease of acetic acid and ammonia better than those by category scaling or magnitude estimation while high cost and time consuming labor involved in triangle tests reduced the merit. The results of this study demonstrated that various sensory methods could be used to measure deodorizing effect of air conditioners and further researches on fast and reliable methods are needed to establish the official procedures. 相似文献
7.
8.
Giovanni Spinelli Marialuisa Melli Eva Arnold Caterina Casano Fabrizio Gianguzza Mirella Ciaccio 《Journal of molecular biology》1980,139(2):111-122
Sea urchin RNA extracted from early and mesenchyme blastula embryos and oocytes and fractionated on denaturing sucrose density gradients, was hybridized with histone DNA recombinants of Psammechinus miliaris (clone λh22) and of Paracentrotus lividus (clone pPH70). Histone sequences are found in the 9 S and larger than 9 S regions of the formamide/sucrose density gradients. The melting of the RNA-DNA duplexes obtained by hybridization of polysomal and high molecular weight RNA of embryos of P. lividus at the stage of early blastula, suggests a degree of heterogeneity in the high Mr RNA. The high Mr RNA contains at least four of the five histone gene sequences covalently linked. 相似文献
9.
Eva M. del Campo Leonardo M. Casano Eva Barreno 《Molecular phylogenetics and evolution》2013,66(3):857-867
The RPL10A gene encodes the RPL10 protein, required for joining 40S and 60S subunits into a functional 80S ribosome. This highly conserved gene, ubiquitous across all eukaryotic super-groups, is characterized by a variable number of spliceosomal introns, present in most organisms. These properties facilitate the recognition of orthologs among distant taxa and thus comparative studies of sequences as well as the distribution and properties of introns in taxonomically distant groups of eukaryotes. The present study examined the multiple ways in which RPL10A conservation vs. sequence changes in the gene over the course of evolution, including in exons, introns, and the encoded proteins, can be exploited for evolutionary analysis at different taxonomic levels. At least 25 different positions harboring introns within the RPL10A gene were determined in different taxa, including animals, plants, fungi, and alveolates. Generally, intron positions were found to be well conserved even across different kingdoms. However, certain introns seemed to be restricted to specific groups of organisms. Analyses of several properties of introns, including insertion site, phase, and length, along with exon and intron GC content and exon–intron boundaries, suggested biases within different groups of organisms. The use of a standard primer pair to analyze a portion of the intron-containing RPL10A gene in 12 genera of green algae within Chlorophyta is presented as a case study for evolutionary analyses of introns at intermediate and low taxonomic levels. Our study shows that phylogenetic reconstructions at different depths can be achieved using RPL10A nucleotide sequences from both exons and introns as well as the amino acid sequences of the encoded protein. 相似文献