Expression of alternansucrase in potato plants

Alternan, which consists of alternating α-(1→3)/α-(1→6)-linked glucosyl residues, was produced in potato tubers by expressing a mature alternansucrase (Asr) gene from Leuconostoc mesenteroides NRRL B-1355 in potato. Detection of alternan was performed by enzyme-linked immunosorbent assay in tuber juices, revealing a concentration between 0.3 and 1.2 mg g-1 fresh wt. The Asr transcript levels correlated well with alternan accumulation in tuber juices. It appeared that the expression of sucrose-regulated starch-synthesizing genes (ADP-glucose pyrophosphorylase subunit S and granule-bound starch synthase I) was down-regulated. Despite this, the physico-chemical properties of the transgenic starches were unaltered. These results are compared to those obtained with other transgenic potato plants producing mutan [α-(1→3)-linked glucosyl residues] and dextran [α-(1→6)-linked glucosyl residues]

Expression of a rice chitinase gene in transgenic banana ('Gros Michel', AAA genome group) confers resistance to black leaf streak disease

Peer reviewe

Towards a more versatile alpha-glucan biosynthesis in plants

peer reviewedDuring the last 10 years, the increased need for starches with novel properties has occupied the research community, and many efforts were concentrated on unraveling the starch bio- synthesis pathways. The knowledge generated in these investigations was subsequently used to produce tailor-made starches in higher plants using recombinant DNA technology. Examples of starches with new functionalities are those with a modified degree of branching (Schwall et al. 2000, Shewma- ker et al. 1994, Kortstee et al. 1996) and the amylose-free starch (Visser et al. 1991a, Kuipers et al.1994), some of which hold potential for applications in the paper-, textile-, plastics-, food and pharmaceutical industry. The accumulation of more starch has also been an objective, but this will not be dis- cussed further here, (see: Slattery et al. 2000). In our laboratory, we have embarked on two generic tech- nologies with a very wide range of applicability: (i) introduction of new linkages types and structural elements using glu- cansucrases, and (ii) engineering granule-boundness by using microbial starch-binding domains (SBDs). It is expected that these technologies will contribute substantially to the biosynthesis of more versatile α-glucans in the near future, leading to starches with altered functionalities that cannot be obtained by conventional breeding. In this study recent developments in starch modification using heterologous expression of microbial genes will be reviewed, with emphasis on the potato plant

Transformed Plant Expressing a Mutansucrase and Synthesizing a Modified Starch

publication date: 2009-12-03; filing date: 2006-01-09The present invention relates to plant cells and plants, which are genetically modified, wherein the genetic modification leads to the expression in plastids of such plant cells and plants of an enzyme having the activity of a mutansucrase. Furthermore, the present invention relates to means and methods for the manufacture of such plant cells and plants. Plant cells and plants of this type synthesise a modified starch. The present invention therefore also relates to the starch synthesised by the plant cells and plants according to the invention as well as to methods for the manufacture of the starch and to the manufacture of starch derivatives of this modified starch

Fusion proteins comprising the catalytic domain of mutansucrase and a starch-binding domain can alter the morphology of amylose-free potato starch granules during biosynthesis

It has been shown previously that mutan can be co-synthesized with starch when a truncated mutansucrase (GtfICAT) is directed to potato tuber amyloplasts. The mutan seemed to adhere to the isolated starch granules, but it was not incorporated in the starch granules. In this study, GtfICAT was fused to the N- or C-terminus of a starch-binding domain (SBD). These constructs were introduced into two genetically different potato backgrounds (cv. Kardal and amf), in order to bring GtfICAT in more intimate contact with growing starch granules, and to facilitate the incorporation of mutan polymers in starch. Fusion proteins of the appropriate size were evidenced in starch granules, particularly in the amf back- ground. The starches from the various GtfICAT/ SBD transformants seemed to contain less mutan than those from transformants with GtfICAT alone, suggesting that the appended SBD might inhibit the activity of GtfICAT in the engineered fusion proteins. Scanning electron microscopy showed that expression of SBD-GtfICAT resulted in alterations of granule morphology in both genetic backgrounds. Surprisingly, the amf starches con- taining SBD-GtfICAT had a spongeous appearance, i.e., the granule surface contained many small holes and grooves, suggesting that this fusion protein can interfere with the lateral interactions of amylopectin sidechains. No differences in phys- ico-chemical properties of the transgenic starches were observed. Our results show that expression of granule-bound and ‘‘soluble’’ GtfICAT can affect starch biosynthesis differently

Subcutaneous Implantable Cardioverter-Defibrillators in Patients With Congenital Heart Disease

International audienc

Relation of outcomes to ABC (Atrial Fibrillation Better Care) pathway adherent care in European patients with atrial fibrillation: an analysis from the ESC-EHRA EORP Atrial Fibrillation General Long-Term (AFGen LT) Registry

International audienceAbstract Aims There has been an increasing focus on integrated, multidisciplinary, and holistic care in the treatment of atrial fibrillation (AF). The ‘Atrial Fibrillation Better Care’ (ABC) pathway has been proposed to streamline integrated care in AF. We evaluated the impact on outcomes of an ABC adherent management in a contemporary real-life European-wide AF cohort. Methods and results Patients enrolled in the ESC-EHRA EURObservational Research Programme in AF General Long-Term Registry with baseline data to evaluate ABC criteria and available follow-up data were considered for this analysis. Among the original 11 096 AF patients enrolled, 6646 (59.9%) were included in this analysis, of which 1996 (30.0%) managed as ABC adherent. Patients adherent to ABC care had lower CHA2DS2-VASc and HAS-BLED scores (mean ± SD, 2.68 ± 1.57 vs. 3.07 ± 1.90 and 1.26 ± 0.93 vs. 1.58 ± 1.12, respectively; P < 0.001). At 1-year follow-up, patients managed adherent to ABC pathway compared to non-adherent ones had a lower rate of any thromboembolic event (TE)/acute coronary syndrome (ACS)/cardiovascular (CV) death (3.8% vs. 7.6%), CV death (1.9% vs. 4.8%), and all-cause death (3.0% vs. 6.4%) (all P < 0.0001). On Cox multivariable regression analysis, ABC adherent care showed an association with a lower risk of any TE/ACS/CV death [hazard ratio (HR): 0.59, 95% confidence interval (CI): 0.44–0.79], CV death (HR: 0.52, 95% CI: 0.35–0.78), and all-cause death (HR: 0.57, 95% CI: 0.43–0.78). Conclusion In a large contemporary cohort of European AF patients, a clinical management adherent to ABC pathway for integrated care is associated with a significant lower risk for cardiovascular events, CV death, and all-cause death