Blog List

Monday 14 November 2016

Gene Transfer Techniques and their relevance to Woody Plants

Published Date
Volume 66 of the series Forestry Sciences pp 1-24
  • Subhash C. Minocha
  • John C. Wallace

Abstract

For decades, the concept of foreign DNA transfer into plant cells and its integration into the genome of the recipient cell was an intriguing curiosity (Lurquin, 1977). It was not until the advent of Southern hybridization (Southern, 1975) and the availability of restriction enzymes that the presence of `non-plant’ DNA (in this case, the T-DNA of Agrobacterium tumefaciens) in plant cells was unequivocally demonstrated (Chilton et al., 1977; Roberts, 1982). Once it became known that Agrobacterium could transfer a defined segment of its plasmid DNA into plant cells and that this DNA could become covalently integrated into the genomic DNA of the host cell, where it was expressed, plans for the transfer of known foreign genes into plant cells could be laid out (Roberts, 1982). An understanding of the roles of auxin and cytokinin biosynthetic genes that were present on the T-DNA and the availability of tools to selectively recombine genes with the Ti plasmid led to the possibility of genetic engineering for improvement of plants. Since these discoveries in the late 1970s, both the tools and the concepts of genetic manipulation of plants using specific genes have improved tremendously. During this period, we have revisited the earlier approaches of direct passive uptake of DNA, improved the efficiency of gene transfer by direct and vector-mediated techniques, designed genes for optimal expression in the transgenic cells/plants, and cloned a plethora of genes for potential use in genetic improvement of plants. As a result, during the past two years (1998–1999), a large proportion of the field-planted material of some of our major crops has been genetically modified using the tools of genetic engineering (Birch, 1997; Moffat, 1998). In addition, these techniques have led to a quantum leap in our understanding of some very basic aspects of plant development, physiology, and biochemistry (Birch, 1997). In this regard, transformation technology has helped us to tag and clone genes that were previously known only from the phenotypes they produce, to test critical hypotheses regarding the developmental roles of several of these genes, and to explore the regulatory aspects of key metabolic pathways (Koncz et al., 1989; Klein et al., 1990; Feldmann, 1991; Lindsey, 1998; Maes et al., 1999).

For further details log on website :
http://link.springer.com/chapter/10.1007/978-94-017-2313-8_8

Effect of Types of Wood on the Thermal Conductivities of Wood Saw Dust Particle Reinforced Composites

Published Date
doi:10.1016/j.proeng.2014.11.812
10th International Conference on Mechanical Engineering, ICME 2013
Open Access, Creative Commons license
Author 


  • M. Faruk Hossain
  • Shoumya Nandy Shuvo ,
  • M.A. Islam
    • Materials and Metallurgical Engineering Department, BUET, Dhaka-1000

    Abstract

    Wood dust reinforcing polymer matrix composites has been one of the epoch-making and pioneering study both from scientific and economical eye over the last decades, due to the eco-friendliness and aesthetical properties. Wood dust is suitable and beguiling filler for thermoset polymers due to its cost effectiveness, low density and high specific properties. It is biodegradable and nonabrasive during processing. The research was proceeded with the objective of evaluating the effect of different types of wood saw dust on the properties of composite materials. In this experiment, thermal behaviours of composites reinforced with wood dust particles of various woods (three types of woods) were investigated. Size was a viable parameter to control the properties of developed composites. As a result two different particle sizes as medium and coarse sized wood particles were used to develop the composites and characterize their thermal conductivities. The results of the experiment thus observed were quite interesting. Pure polyester has been found to have lower thermal conductivity compared to that of any wood reinforced polyester and that wood strength or true density has been found to influence the thermal conductivity of the as-received polymer. With increase in the dust particle content, thermal conductivities of all composites have been found to increase.

    References 


    • [1]
    • Encyclopedia of Polymer Science Engineering, H.F. Mark Edition, John Wiley and Sons, New York, 1985.


      • [7]
      • H.D. RozmanH. IsmailR.M. JaffriA. AminullahZ.A. Mohd Ishak
      • Mechanical properties of polyethylene-oil palm empty fruit bunch composites
      • Journal of Polymer Plastic Technology and EngineeringVolume 37Issue 41998pp. 495–507
      • [8]
      • A.K. BledziS. ReihmaneJ. Gassan
      • Thermoplastics reinforced with wood fillers
      • a literature review of Polymer Plastic Technology and EngineeringVolume 37Issue 41998pp. 451–468
      • [9]
      • H.D. RozmanP.P. LimA. AbusamahR.N. KumarH. IsmailZ.A. Mohd Ishak
      • The physical properties of oil palm empty fruit bunch (EFB) composites made from various thermoplastics
      • International Journal of Polymeric MaterialsVolume 441999pp. 179–195
      • [11]
      • C.A.S. HillH.P.S. Abdul Khali
      • Effect of fiber treatments on mechanical properties of coir or oil palm fiber reinforced polyester composites
      • Journal of Applied Polymer ScienceVolume 782000pp. 1685–1697
      • [14]
      • K. Oksman and J. F. Selin, “Plastics and composites from polylactic acid”, In Wallenberger FT, Weston NE, editors, Natural fibers, plastics and composites, vol-1. Norwell Kluwer Academic Press, 2004.
      • [15]
      • H. DalavagC. KlasonH.E. Stromvall
      • The efficiency of cellulosic fillers in common thermoplastics, filling with processing aids and coupling agents
      • International Journal of Polymeric MaterialsVolume 11Issue 11985pp. 9–38
      • [16]
      • B.D. ParkJ.J. Balatinecz
      • Effects of impact modification on the mechanical properties of wood-fiber thermoplastic composites with high impact polypropylene (HIPP)
      • Journal of Thermoplastic Composite MaterialsVolume 9Issue 41996pp. 342–364
      • [17]
      • Z. NogellovaB.V. KoktaI. Chodak
      • A composite LDPE/wood flour cross-linked by peroxide
      • Journal of Macromolecular Science- Part A: Pure and Applied ChemistryVolume A35Issue 7-81998pp. 1069–1077

    • Selection and peer-review under responsibility of the Department of Mechanical Engineering, Bangladesh University of Engineering and Technology (BUET).
    • ⁎ 
      Corresponding author. Tel.: +880-1711453647.


    For further details log on website :
    http://www.sciencedirect.com/science/article/pii/S1877705814029336

    Advantages and Disadvantages of Fasting for Runners

    Author BY   ANDREA CESPEDES  Food is fuel, especially for serious runners who need a lot of energy. It may seem counterintuiti...