Approximations to the Bayes estimate for a quantal assay with simple exponential tolerance distribution

Approximations to Bayes estimate for quantal assay with simple exponential tolerance distributio

EFFECT OF RIGIDITY OF STRUCTURE ON THE SETTLEMENT OF FOUNDATION

The paper deals with a computation method based on a combined soil model. The model, making use of Repnikov's assumption, is suitable for application and calculation of shallow foundation in case of medium high panel building thus saving construction costs

Transformation and transposon mutagenesis of Leifsonia xyli subsp. Xyli, causal organism of Ratoon Stunting Discease of sugarcane

Conditions have been developed for genetic transformation and insertional mutagenesis in Leifsonia xyli subsp. xyli (Lxx), the causal organism of ratoon stunting disease (RSD), one of the most damaging and intractable diseases of sugarcane internationally. Transformation frequencies ranged from 1 to 10 colony forming units (CFU)/mug of plasmid DNA using Clavibacter/Escherichia coli shuttle vectors pCG188, pDM302, and pDM306 and ranged from 50 to 500 CFU/mug using cosmid cloning vectors pLAFR3 and pLAFR5-km. The transformation/transposition frequency was 0 to 70 CFU/mug of DNA, using suicide vectors pUCD623 and pSLTP2021 containing transposable elements Tn4431 and Tn5, respectively. It was necessary to grow Lxx in media containing 0.1% glycine for electroporation and to amplify large plasmids in a dam(-)/dcm(-) E. coli strain and purify the DNA by anion exchange. To keep selection pressure at an optimum, the transformants were grown on nitrocellulose filters (0.2-mum pore size) on media containing the appropriate antibiotics. Transposon Tn4431 containing a promoterless lux operon from Vibrio fischeri and a tetracycline-resistance gene was introduced on the suicide vector pUCD623. All but 1% of the putative transposon mutants produce light, indicating transposition into functional Lxx genes. Southern blot analysis of these transformants indicates predominantly single transposon insertions at unique sites. The cosmid cloning vector pLAFR5-km was stably maintained in Lxx. The development of a transformation and transposon mutagenesis system opens the way for molecular analysis of pathogenicity determinants in Lxx

Development of sugarcane as a biofactory for biopolymers

Sugarcane has the potential to be a key crop in the biofactory revolution. It is the second fastest growing tropical grass, produces a large biomass, partitions carbon into sucrose at up to 42% of the dry weight of the stalk, has a mobile pool of hexose sugars through most of its life cycle, is difficult to get to produce viable seed and therefore is vegetatively propagated, and can be harvested multiple times before replanting. To test the ability of sugarcane to be a biofactory we chose to engineer into sugarcane plants the genetic pathway for poly-3-hydroxybutyrate (PHB). The three gene pathway, phaA, phaB and phaC has been successfully engineered into a number of plant species. However, either levels of PHB accumulation were low or one or more of the products from the PHB biosynthetic pathway had adverse effects on the transgenic plants. We have targeted the products from the Ralstonia eutropha PHB biosynthetic pathway to several subcellular compartments of sugarcane. We found that the polymer accumulated in the leaves of chloroplast-targeted lines at levels up to 1.88% of dry weight and to 0.01% when the genes were targeted to the cytosol. No polymer was produced in lines harbouring the PHB biosynthetic genes targeted to mitochondria. We conducted a glasshouse trial with replicates of six independent lines of PHB-producing sugarcane. PHB production remained constant during the duration of the trial. Analysis of height, weight and sugar levels revealed no significant difference between transgenic and wild type lines

Application of biotechnology for future sugar industry diversification

Proceedings of the 2002 Conference of the Australian Society of Sugar Cane Technologist