Search for genetic variants in the p66Shc longevity gene by PCR-single strand conformational polymorphism in patients with early-onset cardiovascular disease.

Background: Among the possible candidate genes for atherosclerosis experimental data point towards the longevity gene p66(Shc). The p66(Shc) gene determines an increase of intracellular reactive oxygen species (ROS), affecting the rate of oxidative damage to nucleic acids. Knock-out p66(Shc-/-) mice show reduction of systemic oxidative stress, as well as of plasma LDL oxidation, and reduced atherogenic lesions. Thus, p66(Shc) may play a pivotal role in controlling oxidative stress and vascular dysfunction in vivo. Methods: We searched for sequence variations in the p66(Shc) specific region of the Shc gene and its upstream promoter by PCR-SSCP in a selected group of early onset coronary artery disease ( CAD) subjects (n. 78, mean age 48.5 +/- 6 years) and in 93 long-living control subjects ( mean age 89 +/- 6 years). Results: The analysis revealed two variant bands. Sequencing of these variants showed two SNPs: -354T > C in the regulatory region of p66(Shc) locus and 92C > T in the p66 specific region (CH2). Both these variants have never been described before. The first substitution partially modifies the binding consensus sequence of the SpI transcription factor, and was detected only in two heterozygous carriers (1 CAD subjects and 1 control subject). The 92C > T substitution in the CH2 region consists in an amino acid substitution at codon 31 (proline to leucine, P31L), and was detected in heterozygous status only in one CAD subject. No subjects homozygous for the two newly described SNPs were found. Conclusion: Only two sequence variations in the p66(Shc) gene were observed in a total of 171 subjects, and only in heterozygotes. Our observations, in accordance to other studies, suggest that important variations in the p66(Shc) gene may be extremely rare and probably this gene is not involved in the genetic susceptibility to CAD

Mutations at the same residue (R50) of Kir6.2 (KCNJ11) that cause neonatal diabetes produce different functional effects

Heterozygous mutations in the human Kir6.2 gene (KCNJ11), the pore-forming subunit of the ATP-sensitive K(+) channel (K(ATP) channel), are a common cause of neonatal diabetes. We identified a novel KCNJ11 mutation, R50Q, that causes permanent neonatal diabetes (PNDM) without neurological problems. We investigated the functional effects this mutation and another at the same residue (R50P) that led to PNDM in association with developmental delay. Wild-type or mutant Kir6.2/SUR1 channels were examined by heterologous expression in Xenopus oocytes. Both mutations increased resting whole-cell currents through homomeric and heterozygous K(ATP) channels by reducing channel inhibition by ATP, an effect that was larger in the presence of Mg(2+). However the magnitude of the reduction in ATP sensitivity (and the increase in the whole-cell current) was substantially larger for the R50P mutation. This is consistent with the more severe phenotype. Single-R50P channel kinetics (in the absence of ATP) did not differ from wild type, indicating that the mutation primarily affects ATP binding and/or transduction. This supports the idea that R50 lies in the ATP-binding site of Kir6.2. The sulfonylurea tolbutamide blocked heterozygous R50Q (89%) and R50P (84%) channels only slightly less than wild-type channels (98%), suggesting that sulfonylurea therapy may be of benefit for patients with either mutation

Maturity-Onset Diabetes of the Young in Children With Incidental Hyperglycemia:: A multicenter Italian study of 172 families

OBJECTIVE - To investigate the prevalence of maturity-onset diabetes of the young (MODY) in Italian children With incidental hyperglycemia. RESEARCH DESIGN AND METHODS - Among 748 subjects age 1-18 years with incidental hyperglycemia, minimal diagnostic criteria for MODY were met by 172 families. Mutational analyses of the glucokinase (GCK) and hepatocyte nuclear factor lot (HNF1A) genes were performed. RESULTS - We identified 85 GCK gene mutations in 109 probands and 10 HNF1A mutations in 12 probands. In GCK patients, the median neonatal weight and age at the first evaluation were lower than those found in patients with HNF1A mutations. Median fasting plasma glucose and impaired fasting glucose/impaired glucose tolerance frequency after oral glucose tolerance testing were higher in GCK patients, who also showed a lower frequency of diabetes than HNF1A patients. CONCLUSIONS - GCK mutations are the prevailing cause of MODY (63.4%) when the index case is recruited in Italian children with incidental hyperglycemia

New radiocarbon measurements from Tasmanian Huon pine: closing the current gap in tree-ring based calibration data for the early Younger Dryas.

The European absolute tree-ring chronologies have recently extended back to 12,594 cal BP [1], covering most of the Younger Dryas (YD). Radiocarbon data from these chronologies spanning the past 12,400 cal BP have been used to construct the younger part of the current internationally ratified calibration curve IntCal04 [2]. For the Late Glacial, radiocarbon data from a floating 1382-ring pine chronology are also available [3]. Here we present new high-precision, high-resolution radiocarbon measurements for the early YD chronozone derived from 4 sub-fossil logs of Huon pine with clearly defined annual tree rings. These logs were excavated from alluvial sediments along Stanley River in north-western Tasmania, Australia. A total of 137 samples, mostly decadal, were pretreated to alpha-cellulose, then converted to graphite and measured by AMS using the ANTARES facility at ANSTO [4], with a typical precision of 0.3-0.4%. A floating 617-ring Huon pine chronology has been constructed based on ring width and radiocarbon measurements. Our high-precision decadal 14C record, covering an age range from 10,350 to 10,760 14C years BP, has been linked to the European absolute tree-ring and floating Late Glacial Pine chronologies, bridging the current gap in the European tree-ring chronologies during the early YD and making a continuous and reliable atmospheric 14C record for the past 14,000 cal BP. Variations in atmospheric 14C during the YD recorded in tree rings and the possible mechanisms are also discussed.CEDAD; CIRCE; LABEC; ICT

Crop Updates - 2003 Oilseeds

This session covers fifteen papers from different authors ACKNOWLEDGMENTS VARIETIES Large scale canola varietal evaluation in WA, Peter Nelson, Oilseeds WA Performance of IT and TT canola varieties in the medium and high rainfall agzones of WA 2001-02, Graham Walton, Hasan Zaheer and Paul Carmody, Department of Agriculture QUALITY Reproductive biology, cotyledon development and oil accumulation in canola, J.A. Fortescue and D.W. Turner, School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia Plant and environmental factors affecting oil concentration in canola – a mini-review, D.W. Turner, School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia Potential benefits from interspecific crosses between canola and ‘near canola’ quality Indian mustard, Janet Wroth, School of Plant Biology, The University of Western Australia (UWA), Wallace Cowling, School of Plant Biology, UWA and CBWA Pty Ltd, Anh-Van Pham, School of Mathematics and Statistics, UWA NUTRITION, AGRONOMY AND MACHINERY Timing of nitrogen application for producing canola grain and oil, R. F. Brennan, Department of Agriculture Managing canola for soil type and moisture stress, Paul Carmody and Hasan Zaheer Department of Agriculture Machinery lessons from 2002 – canola establishment, Glen Riethmuller, Greg Hamilton and Jo Hawksley, Department of Agriculture Machinery lessons from 2002 – harvesting short crops, Glen Riethmuller, Department of Agriculture Does increasing canola seeding rate reduce the competitiveness of grass weeds? Zaicou-Kunesch, C.M., Zaheer, S.H. and Eksteen, D, Department of Agriculture PESTS AND DISEASES Aphid damage to canola – not all cultivars are equal, Françoise A. Berlandier and Christiaan Valentine, Department of Agriculture Should we be worried about developing insecticide resistance in aphids? Owain Edwards, CSIRO Entomology Benefits provided by treating canola seed with imidacloprid seed dressing, Roger Jones, Brenda Coutts, Lisa Smith and Jenny Hawkes, Department of Agriculture, and Centre for Legumes in Mediterranean Agriculture Blackleg levels in canola in 2002, Ravjit Khangura1, Moin Salam1, Art J Diggle1 and Martin J Barbetti1,2 1Department of Agriculture, 2University of Western Australia DBM in canola, Kevin Walden, Department of Agricultur

Mutant INS-Gene Induced Diabetes of Youth: Proinsulin Cysteine Residues Impose Dominant-Negative Inhibition on Wild-Type Proinsulin Transport

Recently, a syndrome of Mutant INS-gene-induced Diabetes of Youth (MIDY, derived from one of 26 distinct mutations) has been identified as a cause of insulin-deficient diabetes, resulting from expression of a misfolded mutant proinsulin protein in the endoplasmic reticulum (ER) of insulin-producing pancreatic beta cells. Genetic deletion of one, two, or even three alleles encoding insulin in mice does not necessarily lead to diabetes. Yet MIDY patients are INS-gene heterozygotes; inheritance of even one MIDY allele, causes diabetes. Although a favored explanation for the onset of diabetes is that insurmountable ER stress and ER stress response from the mutant proinsulin causes a net loss of beta cells, in this report we present three surprising and interlinked discoveries. First, in the presence of MIDY mutants, an increased fraction of wild-type proinsulin becomes recruited into nonnative disulfide-linked protein complexes. Second, regardless of whether MIDY mutations result in the loss, or creation, of an extra unpaired cysteine within proinsulin, Cys residues in the mutant protein are nevertheless essential in causing intracellular entrapment of co-expressed wild-type proinsulin, blocking insulin production. Third, while each of the MIDY mutants induces ER stress and ER stress response; ER stress and ER stress response alone appear insufficient to account for blockade of wild-type proinsulin. While there is general agreement that ultimately, as diabetes progresses, a significant loss of beta cell mass occurs, the early events described herein precede cell death and loss of beta cell mass. We conclude that the molecular pathogenesis of MIDY is initiated by perturbation of the disulfide-coupled folding pathway of wild-type proinsulin