6,217 research outputs found

    Irregular deposition of cell wall polymers resulting from defective cellulose synthase complexes

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    The crystalline cellulose microfibril is formed by the spontaneous association of about 36 β-D-glucan chains, which are simultaneously synthesised by a large membrane-localised multi-enzyme cellulose synthase complex. Antisense technology has been previously employed separately on two of the constituent cellulose synthase catalytic subunits (CesA) of the complex in potato (Solanum tuberosum), namely CesA2 and CesA4, to generate potato tuber cell walls with reduced cellulose content. Genetic crossing of two transgenic potato lines csr2-1 and csr4-8 was carried out to investigate the effects of two defective CesAs in the same genetic background, with respect to cellulose deposition in the potato tuber cell walls. It was striking to observe, through fluorescence microscopy with calcofluor white, a strong fluorescence in the cell corners and less prominent and uneven fluorescence around the cells of the csr2 tubers as compared to others. It was also noted that these phenotypes were not pronounced in the csr2/csr4 double transformants as expected

    Evolution of Music by Public Choice

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    Music evolves as composers, performers, and consumers favor some musical variants over others. To investigate the role of consumer selection, we constructed a Darwinian music engine consisting of a population of short audio loops that sexually reproduce and mutate. This population evolved for 2,513 generations under the selective influence of 6,931 consumers who rated the loops’ aesthetic qualities. We found that the loops quickly evolved into music attributable, in part, to the evolution of aesthetically pleasing chords and rhythms. Later, however, evolution slowed. Applying the Price equation, a general description of evolutionary processes, we found that this stasis was mostly attributable to a decrease in the fidelity of transmission. Our experiment shows how cultural dynamics can be explained in terms of competing evolutionary forces

    Tomato: a crop species amenable to improvement by cellular and molecular methods

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    Tomato is a crop plant with a relatively small DNA content per haploid genome and a well developed genetics. Plant regeneration from explants and protoplasts is feasable which led to the development of efficient transformation procedures. In view of the current data, the isolation of useful mutants at the cellular level probably will be of limited value in the genetic improvement of tomato. Protoplast fusion may lead to novel combinations of organelle and nuclear DNA (cybrids), whereas this technique also provides a means of introducing genetic information from alien species into tomato. Important developments have come from molecular approaches. Following the construction of an RFLP map, these RFLP markers can be used in tomato to tag quantitative traits bred in from related species. Both RFLP's and transposons are in the process of being used to clone desired genes for which no gene products are known. Cloned genes can be introduced and potentially improve specific properties of tomato especially those controlled by single genes. Recent results suggest that, in principle, phenotypic mutants can be created for cloned and characterized genes and will prove their value in further improving the cultivated tomato.

    The review of recent advances in fish genetics and biotechnology

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    Great advances have been, and are being made in our knowledge of the genetics and molecular biology (including genomics, proteomics and structural biology). Global molecular profiling technologies such as microassays using DNA or oligonucleotide chip, and protein and lipid chips are being developed. The application of such biotechnological advances are inevitable in aquaculture in the areas of improvement of aquaculture stocks where many molecular markers such as RFLPs, AFLDs and RAPD are now available for genome analysis, finger printing and genetic linkage mapping. Transgenic technology has been developed in a number of fish species and research is being pursed to produce transgenic fish carrying genes that encode antimicrobial peptides such as lysozyme thereby achieving disease resistance in fish. Also it is a short cut to achieving genetic change for fast growth and other desirable traits like early sexual maturity, temperature tolerance and feed conversion efficiency. KEYWORDS: Fish genetics, transgenesis, monoploidy, diploidy, polyploidy,gynogenesis, androgenesis, cryopreservation

    Making the most of clade selection

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    Clade selection is unpopular with philosophers who otherwise accept multilevel selection theory. Clades cannot reproduce, and reproduction is widely thought necessary for evolution by natural selection, especially of complex adaptations. Using microbial evolutionary processes as heuristics, I argue contrariwise, that (1) clade growth (proliferation of contained species) substitutes for clade reproduction in the evolution of complex adaptation, (2) clade-level properties favoring persistence – species richness, dispersal, divergence, and possibly intraclade cooperation – are not collapsible into species-level traits, (3) such properties can be maintained by selection on clades, and (4) clade selection extends the explanatory power of the theory of evolution

    Publish or patent?: Knowledge dissemination in agricultural biotechnology

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    "Plant transformation research has achieved outstanding progress in the development of transgenic crops over the past decades, and the research results have been spread through journal publications and patents. With the recent emergence of stronger intellectual property rights, investments in crop research and the landscape of plant transformation research have changed, along with the patterns of knowledge dissemination. In this paper, we discuss the recent trends in plant transformation research by examining patent and journal publication data during the last decade. The data analysis shows that there have been significant shifts toward applied research by developing countries and toward patenting as a means of knowledge dissemination during the past few decades, reflecting the increasing role of the private sector in developing countries in crop improvement research." from authors' abstractBiotechnology research, patents, Crop improvement, Science and technology, Genetic resources, Biodiversity, Journal publication, Developing countries,

    Evaluation of the Effectiveness of Selected Antibiotics in the Suppression of Agrobacterium from Cowpea (Vigna Unguiculata L. Walp.) Embryo Explants and as Potential Selective Agents in Agrobacterium-Mediated Transformation

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    The purpose of the study was to provide baseline information on Agrobacterium growth control and suitable selective agent(s) for use in in vitro cowpea genetic transformation studies. Ampicillin was identified as an effective alternative to cefotaxime, in suppressing Agrobacterium tumefaciens. It shows no toxicity to cowpea tissues at a concentration of up to 500 mgl-1. Cefotaxime did not inhibit shoot regeneration or growth but ampicillin is more economical than cefotaxime. This study also examined the effect of four different aminoglycoside antibiotics; geneticin, paromomycin, kanamycin and neomycin, on the regeneration of cowpea decapitated embryos, in an attempt to develop a selection system for in vitro cowpea transformation and regeneration. Plant regeneration was completely inhibited by geneticin (50-500 mgl-1), kanamycin (200-500 mgl-1), paromomycin (400-500 mgl-1) and neomycin at (300-500 mgl-1). Kanamycin (200 mgl-1) and geneticin (10 mgl-1) are suggested as potential agents for selection of transformed cowpea tissues
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