Studies: on the nucleic acids of developing, dormant and germinating seeds of vicia faba (L)

Seeds of Vicia faba (L)take about 130 days from the fertilisation of the ovule to become fully mature. After an initial phase of cell division, storage protein is synthesised in the cotyledon cells and accumulates in organelles termed protein bodies. During the latter phase, the RNA, contents of cotyledon cells increase sixfold. Methylated albumin-kieselguhr chromatography revealed that the newly synthesised RNA, consists of 13% low molecular weight RNA and 87% ribosomal RNA, suggesting that storage protein synthesis may be mediated by the mRNA/tRNA/ ribosome mechanism. Isolated protein bodies contain only traces of RNA, indicating that storage protein is not synthesised in these organelles. Biochemical methods show that, during the phase of cell division, there are many free ribosomes and relatively few membrane bound ribosomes. Correlated with the onset of storage protein synthesis, there is a large increase in the numbers of membrane bound ribosomes, but the numbers of free3ribosomes remain approximately constant. Experiments with ( H) - uridine show that there is no interconversion of these two classes of ribosomes, and both were shown to incorporate amino-acids "in vivo". It is suggested, therefore, that each class of ribosomes may be synthesising different groups of proteins, the membrane bound ribosomes being responsible for the synthesis of storage protein.At the cessation of nutrient reserve accumulation, seeds dehydrate and there is a gradual loss of membrane boundribosomes with a subsequent rise in the numbers of free ribosomes.Upon germination, endoplasmic reticulum with associated32ribosomes is formed once more. Experiments with ( P) - ortho-phosphate indicate that these ribosomes are synthesised "de novo", rather than being formed by the attachment of pre-existing, free ribosomes to membranes. The breakdown of various types of nucleic acids was studied during the senescence of testas in seed development, and cotyledons in seed germination

Infuence of the year and HMW glutenin subunits on end-use quality predictors if bread wheat waxy lines

The effects of environment and the high molecular weight glutenins on some quality properties (sedimentation volume, % protein content, and starch pasting viscosity) of bread wheat mutant waxy lines were evaluated. Thirty-eight 100% amylose-free F 2 derived F 6 and F 7 lines were used. The results indicated that the environment did not influence sedimentation volume, mixograph parameters and starch viscosity parameters of waxy flour. Variation in the % protein content was determined mainly by the environment. The sedimentation volume and the mixograph peak development time were influenced by the variation at over expression of Bx7 and the mixograph peak development time was influenced by the Glu-D1 locus. One starch viscosity parameter, time to peak viscosity, was influenced by variation at the Glu-A1 locus. This parameter is significantly lower in the waxy lines than the parent line, which shows the influence of the waxy loci. No significant correlation was observed for sedimentation volume, mixograph parameters, protein content and viscosity parameters of waxy line

A characteristic particle method for traffic flow simulations on highway networks

A characteristic particle method for the simulation of first order macroscopic traffic models on road networks is presented. The approach is based on the method "particleclaw", which solves scalar one dimensional hyperbolic conservations laws exactly, except for a small error right around shocks. The method is generalized to nonlinear network flows, where particle approximations on the edges are suitably coupled together at the network nodes. It is demonstrated in numerical examples that the resulting particle method can approximate traffic jams accurately, while only devoting a few degrees of freedom to each edge of the network.Comment: 15 pages, 5 figures. Accepted to the proceedings of the Sixth International Workshop Meshfree Methods for PDE 201

Relationships between traditional and fundamental dough-testing methods

Two fundamental test systems were used to evaluate the visco-elastic properties of doughs from wheat samples of three varieties grown at four distinct sites. For comparison, tests were also performed with traditional equipment, namely the Mixograph, an extension tester and a Farinograph-type small-scale recording mixer. Uniaxial dough elongation (with an Instron) produced results similar to the conventional extension tester, except that results were provided in fundamental units (Pascals), the critical value recorded being the elongational stress at maximum strain. Stress relaxation measurements were performed following a small initial shear strain. With this method, it was possible to distinguish between the viscosity and the elastic components of dough visco-elasticity. In all the tests the extra dough-strength properties were evident for the variety (Guardian) that had the 5 + 10 glutenin subunits, in contrast to the other two with the 2 + 12 combination of subunits

Polymorphism at High Molecular Weight Glutenin Subunits and Morphological Diversity of Aegilops geniculata Roth Collected in Algeria

A collection of 35 accessions of the tetraploid wild wheat Aegilops geniculata Roth (MM, UU) sampled in northern Algeria was evaluated for morphological and biochemical variability. Morphological and ecological analyses based on morphological traits and bioclimatic parameters, respectively, were assessed using principal component analysis (PCA). Accessions were differentiated by width characters, namely spike’s width, and a weak relationship between morphological traits and ecological parameters was found. Polymorphism of high molecular weight (HMW) glutenin subunits was carried on by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Among accessions analyzed, 27 alleles were identified at the two loci Glu-M1 and Glu-U1: resulting in twenty-nine patterns and a nomenclature was proposed. Two alleles at the Glu-U1 locus expressed a new subunit with a slightly slower mobility than subunit 8. These results provide new information regarding the genetic variability of HMW glutenin subunits, as well as their usefulness in cultivated wheat quality improvement