Étude par coulométrie de la pénétration de l'eau dans des films de polymères formulés

Hulls protection towards settlement and growth of fouling is obtained by antifouling paints with a progressive release of toxic molecules at the ships surface. The research of a new generation of paints more compatible with living species implies to understand the phenomena involved in paints erosion and biocides release. Water penetration in polymeric matrix is important in regard to the control of ester functions hydrolysis and so to the control of bioactive molecules release. Among the different analytical methods aimed at the determination of the water amount in polymers, we have proposed to use coulometry in order to study the water penetration in polymeric films immersed in synthetic sea water. The analytical protocols developed have enabled to understand the evolution of six different matrixes during the immersion and the comparison of their ability to control release. Coulometry has made possible the study of the effects of additives used in the paints formulation on water uptake. Experimental data have shown that additives modify the evolution of the binder during immersion and that activity of paints is complex. Coulometry is a useful method to test polymers aimed at marine applications

Characterisation of genome regions incorporated from an important wild relative into Australian sugarcane

Author for correspondence e-mail: [email protected] audienceMandalay is an important Saccharum spontaneum clone used historically in Australian sugarcane breeding programs, and has given rise to many valuable cultivars. In order to better understand the genetic contribution of Mandalay to Australian varieties and elite parental material, a combined pedigree and quantitative trait loci (QTL) mapping approach was undertaken. A genetic map containing 400 single-dose markers was constructed for the Australian sugarcane clone MQ77–340, one parent of an Australian sugarcane population (Q117 · MQ77–340), using amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers. This cultivar was selected because it is a direct descendent of Mandalay; its grandparents are Korpi, a S. o.cinarum clone, and Mandalay. The 400 markers were scattered onto 101 linkage groups (LGs) with an estimated map length of 3582 cM. The ancestral origin of all of the markers was determined with approximately 25% of the markers shown to originate from Mandalay, and a similar percentage from Korpi. Of the 101 LGs, 65 contained markers originating from Mandalay and/or Korpi. QTL analysis was undertaken using the map and 3 years of field data for three sugar-related traits (pol, brix, and CCS) and using single year .eld data for .bre, stalk weight and cane and sugar yield. Markers from both Mandalay and Korpi were found to be associated with both positive and negative effects on all of the traits analyse

Markers associated with stalk number and suckering in sugarcane colocate with tillering and rhizomatousness QTLs in sorghum

Two important factors influencing sugar yield, the primary focus of sugarcane plant breeding programs, are stalk number and suckering. Molecular markers linked to both of these traits are sought to assist in the identification of high sugar yield, high stalk number, low-suckering sugarcane clones. In this preliminary mapping study, 108 progeny from a biparental cross involving two elite Australian sugarcane clones were evaluated at two sites for two years for both stalk number and suckering. A total of 258 DNA markers, including both restriction fragment length polymorphisms (RFLPs) and radio-labelled amplified fragments (RAFs), were scored and evaluated using single-factor analysis. Sixteen (7 RFLPs and 9 RAFs) and 14 (6 RFLPs and 8 RAFs) markers were identified that were significantly associated (P < 0.01) with stalk number and suckering, respectively, across both years and sites. The seven and six RFLP markers associated with stalk number and suckering, respectively, were generated by eight different RFLP probes, of which seven had been mapped in sorghum and (or) sugarcane. Of significant interest was the observation that all seven RFLP probes could be shown to be located within or near QTLs associated with tillering and rhizomatousness in sorghum. This observation highlights the usefulness of comparative mapping between sorghum and sugarcane and suggests that the identification of useful markers for stalk number and suckering in sugarcane would be facilitated by focussing on sorghum QTLs associated with related traits