ABSTRACT
A database containing information on the trait complex for terminal phloem of dicots leaf having been created during the last thirty years was analyzed. The typology of terminal phloem was verified. The monotypy of plant taxa up to the family level was confirmed. For orders and subclasses, the wide distribution of structural parallelisms was demonstrated. The lists of plant families with similar structures of the phloem terminals was elaborated. As a result of comparative analysis of these lists and paleobotanic data on the age of plant families, the specificity of the types of terminal phloem and the associated morphological and functional characteristics of the groups of families of the same evolutionary, age were revealed. Ancestral type prevails among the families belonging to Prodicots, which were emerged during Cretaceous. Symplastic type is characteristic to the families of Eudicots and biomes appeared in Paleogene, while the apoplastic type is characteristic to the families and biomes of Neogene. For each group to taxa, plant stem and root parasitism is characteristic for the crown taxa completing the structural sequences of trees and herbs. All these data allow discussion of the questions of climatic adaptogenesis of the character complex studied here, the impossibility of structural iterations in morphological evolution, and the reasons of similarities and differences in the evolutionary and contemporary zonal series of the terminal phloem in Dicots.
Subject(s)
Adaptation, Biological , Biodiversity , Biological Evolution , Phloem/classification , Phylogeny , Plant Leaves/classification , Plants/classification , Phloem/anatomy & histology , Plant Leaves/anatomy & histologyABSTRACT
The physico-chemical properties of ribosomes and rRNA isolated from the mitochondria of the phytoflagellata Astasia longa were studied. It was shown that the mitochondrial ribosomes of A. longa have the sedimentation coefficient of 81S (those of the cytoplasm-82S); upon a decrease of Mg2+ concentration in the medium they dissociate into subparticles with sedimentation coefficients of 60 and 45S. The relative protein content in the mitochondrial ribosomes of A. longa is equal to 42% (rho = 1,60 g/cm3), that of cytoplasmic ribosomes-49%. The molecular weights of mitochondrial rRNA are equal to 1,05 . 10(6) and 0,71 . 10(6) and differ from those for cytoplasmic rRNA (1,32 . 10(6) and 0,94 . 10(6)). It was shown that the GC-content in mitochondrial rRNA is equal to 32,0 mol. %, that in cytoplasmic rRNA-55,9 mol. %. Thus, the mitochondrial ribosomes of A. longa differ in some of their properties from both procaryotic and eucaryotic ribosomes and are probably related to a special type of mitochondrial ribosomes.
Subject(s)
Eukaryota/ultrastructure , Mitochondria/ultrastructure , Ribosomes/ultrastructure , Animals , Base Composition , Cell Fractionation/methods , Molecular Weight , Protein Binding , RNA, Ribosomal/analysis , Ribosomal Proteins/analysisABSTRACT
The methods of extracting total protein from the biomass of Spirulina platensis are discussed. The results of studying different procedures of cell wall disruption, soluble protein extraction and precipitation are presented. The best results can be obtained using mechanical disintegration of Spirulina cells for 20 min (at a temperature not higher than 25 degrees C), soluble protein extraction with 0.4% NaOH, and its subsequent precipitation at the isoelectric point with 5% HCl.
Subject(s)
Bacteria/analysis , Bacterial Proteins/isolation & purification , Evaluation Studies as Topic , Hydrogen-Ion Concentration , Methods , TemperatureABSTRACT
Ribosomes and rRNAs were isolated from cells of green-blue alga Anabaena variabilis. The sedimentation properties of the ribosomes as well as density, molecular weights and nucleotide composition of rRNAs were determined. The ribosomes were found to have the S20,w value equal to 67.2+/-0.4S, whereas those of the ribosome subunits were 48.6+/-0.8 and 29.5+/-1.1S. The buoyant density of the ribosomes in CsCl was 1.641+/-+/-0.002 g/cm3; a calculated relative protein content was 35%. The molecular weights of rRNAs estimated by electrophoresis in PAAG containing 0.5% agarose, are 1.1-10(-6) and 0.56-10(6) daltons. The nucleotide composition of rRNA was determined and rRNA was shown to belong to the GC type. Consequently, the blue-green alga ribosomes do not differ in the parameters studied from bacterial ribosomes.
Subject(s)
Cyanobacteria/ultrastructure , RNA, Ribosomal , Ribosomes , Centrifugation, Density Gradient , Chemical Phenomena , Chemistry , Cyanobacteria/analysis , Molecular Weight , Nucleotides , RNA, Ribosomal/isolation & purification , Ribosomes/analysisABSTRACT
Nucleotide composition of the sum total DNA of B. bifidum, biotype III, was determined by paper chromatography in combination with ultraviolet spectrophotometry. DNA of B. bifidum was referred to the GC-type (GC -- 62.6 mol%). Two additional nitrogen bases were present in the DNA composition; 5-methylcytosine and 6-methylaminopurine -- 0.45 mol% and 0.20 mol%, respectively. Nucleotide composition of the sum total RNA was studied with the aid of high-voltage electrophoresis in combination with ultraviolet spectrophotometry. The sum total RNA was referred to the high GC-type (GC -- 64.9 mol%). These data permit to consider it reasonable to refer bifidobacteria to the Bifidobacterium genus.
