Medical Library

The flowering locus Hr colocalizes with a major QTL affecting winter frost tolerance in Pisum sativum L.

An understanding of the genetic determinism of frost tolerance is a prerequisite for the development of frost tolerant cultivars for cold northern areas. In legumes, it is not known to which extent vernalization requirement or photoperiod responsiveness are necessary for the development of frost tolerance. In pea (Pisum sativum L.) however, the flowering locus Hr is suspected to influence winter frost tolerance by delaying floral initiation until after the main winter freezing periods have passed. The objective of this study was to dissect the genetic determinism of frost tolerance in pea by QTL analysis and to assess the genetic linkage between winter frost tolerance and the Hr locus. A population of 164 recombinant inbred lines (RILs), derived from the cross Champagne x Terese was evaluated both in the greenhouse and in field conditions to characterize the photoperiod response from which the allele at the Hr locus was inferred. In addition, the population was also assessed for winter frost tolerance in 11 field conditions. Six QTL were detected, among which three were consistent among the different experimental conditions, confirming an oligogenic determinism of frost tolerance in pea. The Hr locus was found to be the peak marker for the highest explanatory QTL of this study. This result supports the hypothesis of the prominent part played by the photoperiod responsiveness in the determinism of frost tolerance for this species. The consistency of three QTL makes these positions interesting targets for marker-assisted selection.

Lejeune-Hénaut I, Hanocq E, Béthencourt L, Fontaine V, Delbreil B, Morin J, Petit A, Devaux R, Boilleau M, Stempniak JJ, Thomas M, Lainé AL, Foucher F, Baranger A, Burstin J, Rameau C, Giauffret C.

UMR INRA/USTL SADV, Estrées-Mons BP50136, 80203, Péronne Cedex, France, lejeune@mons.inra.fr.

A grapevine (Vitis vinifera L.) genetic map integrating the position of 139 expressed genes.

Grapevine molecular maps based on microsatellites, AFLP and RAPD markers are now available. SSRs are essential to allow cross-talks between maps, thus upgrading any growing grapevine maps. In this work, single nucleotide polymorphisms (SNPs) were developed from coding sequences and from unique BAC-end sequences, and nested in a SSR framework map of grapevine. Genes participating to flavonoids metabolism and defence, and signal transduction pathways related genes were also considered. Primer pairs for 351 loci were developed from ESTs present on public databases and screened for polymorphism in the \”Merzling\” (a complex genotype Freiburg 993-60 derived from multiple crosses also involving wild Vitis species) x Vitis vinifera (cv. Teroldego) cross population. In total 138 SNPs, 108 SSR markers and a phenotypic trait (berry colour) were mapped in 19 major linkage groups of the consensus map. In specific cases, ESTs with putatively related functions mapped near QTLs previously identified for resistance and berry ripening. Genes related to anthocyanin metabolism mapped in different linkage groups. A myb gene, which has been correlated with anthocyanin biosynthesis, cosegregated with berry colour on linkage group 2. The possibility of associating candidate genes to known position of QTL is discussed for this plant.

Salmaso M, Malacarne G, Troggio M, Faes G, Stefanini M, Grando MS, Velasco R.

Genetics and Molecular Biology Department, Istituto Agrario San Michele all’Adige, via Mach 1, 38010, San Michele a/A (TN), Italy, marzia.salmaso@gmail.com.

Susceptibility to Fusarium head blight is associated with the Rht-D1b semi-dwarfing allele in wheat.

Fusarium head blight (FHB) is an important disease of wheat worldwide. The cultivar Spark is more resistant than most other UK winter wheat varieties but the genetic basis for this is not known. A mapping population from a cross between Spark and the FHB susceptible variety Rialto was used to identify quantitative trait loci (QTL) associated with resistance. QTL analysis across environments revealed nine QTL for FHB resistance and four QTL for plant height (PH). One FHB QTL was coincident with the Rht-1D locus and accounted for up to 51% of the phenotypic variance. The enhanced FHB susceptibility associated with Rht-D1b is not an effect of PH per se as other QTL for height segregating in this population have no influence on susceptibility. Experiments with near-isogenic lines supported the association between susceptibility and the Rht-D1b allele conferring the semi-dwarf habit. Our results demonstrate that lines carrying the Rht-1Db semi-dwarfing allele are compromised in resistance to initial infection (type I resistance) while being unaffected in resistance to spread within the spike (type II resistance).

Srinivasachary , Gosman N, Steed A, Simmonds J, Leverington-Waite M, Wang Y, Snape J, Nicholson P.

Crop Genetics, John Innes Centre, Norwich Research Park, Colney Lane, Norwich, NR4 7UH, UK.

The adult plant rust resistance loci Lr34/Yr18 and Lr46/Yr29 are important determinants of partial resistance to powdery mildew in bread wheat line Saar.

Powdery mildew, caused by Blumeria graminis f. sp. tritici is a major disease of wheat (Triticum aestivum L.) that can be controlled by resistance breeding. The CIMMYT bread wheat line Saar is known for its good level of partial and race non-specific resistance, and the aim of this study was to map QTLs for resistance to powdery mildew in a population of 113 recombinant inbred lines from a cross between Saar and the susceptible line Avocet. The population was tested over 2 years in field trials at two locations in southeastern Norway and once in Beijing, China. SSR markers were screened for association with powdery mildew resistance in a bulked segregant analysis, and linkage maps were created based on selected SSR markers and supplemented with DArT genotyping. The most important QTLs for powdery mildew resistance derived from Saar were located on chromosomes 7DS and 1BL and corresponded to the adult plant rust resistance loci Lr34/Yr18 and Lr46/Yr29. A major QTL was also located on 4BL with resistance contributed by Avocet. Additional QTLs were detected at 3AS and 5AL in the Norwegian testing environments and at 5BS in Beijing. The population was also tested for leaf rust (caused by Puccinia triticina) and stripe rust (caused by P. striiformis f. sp. tritici) resistance and leaf tip necrosis in Mexico. QTLs for these traits were detected on 7DS and 1BL at the same positions as the QTLs for powdery mildew resistance, and confirmed the presence of Lr34/Yr18 and Lr46/Yr29 in Saar. The powdery mildew resistance gene at the Lr34/Yr18 locus has recently been named Pm38. The powdery mildew resistance gene at the Lr46/Yr29 locus is designated as Pm39.

Lillemo M, Asalf B, Singh RP, Huerta-Espino J, Chen XM, He ZH, Bjørnstad A.

Department of Plant and Environmental Sciences, Norwegian University of Life Sciences, P.O. Box 5003, 1432 , Ã…s, Norway, morten.lillemo@umb.no.

[Value of breast MRI as supplement to mammography and sonography for high risk breast cancer patients.]

PURPOSE: The aim of this study is to give an overview on early detection of breast cancer in patients with an increased risk of breast cancer. Sensitivities and diagnostic accuracies of breast MRI, mammography and ultrasound were compared. MATERIAL AND METHODS: A systematic literature search of the past 3 years was performed. Studies which compared breast imaging modalities and used image-guided biopsy results as standard of reference were included. Patients included had to have had an increased lifetime risk for breast cancer (>15%). RESULTS: Regarding sensitivity and diagnostic accuracy, breast MRI performed best in comparison to the other modalities within this collective of patients. Sensitivities ranged from 71-100%, 0-78%, and 13-65%, for MRI, mammography, and ultrasound, respectively CONCLUSION: Breast MRI is a well established tool for screening in patients at high risk for developing breast cancer and is a valuable supplement to mammography and ultrasound within this selected cohort of patients.

Schlossbauer T, Hellerhoff K, Reiser M.

Institut für Klinische Radiologe, Klinikum Großhadern der Ludwig-Maximilians-Universität München, Marchioninistr. 15, 81377, München, Deutschland, thomas.schlossbauer@med.uni-muenchen.de.

[The role of radiologists in emergency medicine and shock room management - new challenges!]

Schueller G, Imhof H.

Univ.-Klinik für Radiodiagnostik, Medizinische Universität Wien, Währinger Gürtel 18-20, A-1090, Wien, Österreich, gerd.schueller@meduniwien.ac.at.

Digital preparation of a probable neoceratopsian preserved within an egg, with comments on microstructural anatomy of ornithischian eggshells.

We describe the first known embryo of a neoceratopsian dinosaur, perhaps the most ubiquitous Laurasian group of Cretaceous dinosaurs, which is preserved completely enclosed within an egg. This specimen was collected from Late Cretaceous beds of southern Mongolia, which commonly preserve fossils of the neoceratopsian, Yamaceratops dorngobiensis. The small egg was scanned using high-resolution X-ray computed tomography and digitally prepared from the matrix. The preserved and imaged elements support a diagnosis of the embryo to Neoceratopsia and allow preliminary observations of ontogenetic transformations within this group. The addition of an embryo also adds another important data point to the already impressive postnatal ontogenetic series that are available for this clade.

Balanoff AM, Norell MA, Grellet-Tinner G, Lewin MR.

Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY, 10024, USA, abalanoff@amnh.org.

Pulmonary vein stents in infants and children: is there lasting benefit?

Sreeram N, Emmel M, Trieschmann U, Brockmeier K, Bennink G.

Department of paediatric cardiology, University Hospital of Cologne, Kerpenerstraße 62, 50937, Cologne, Germany, n.sreeram@uni-koeln.de.

Vascular endothelial functions, carotid intima-media thickness, and soluble CD40 ligand levels in dipper and nondipper essential hypertensive patients.

OBJECTIVE: The lack of nocturnal decline in blood pressure (BP) is associated with an increase in cardiovascular events. Soluble CD40 ligand (sCD40L) is involved in the pathogenesis of risk factor-related vascular damage. The purpose of this study was to examine the relationship between vascular endothelial functions, carotid intima-media thickness (cIMT), plasma sCD40L levels and circadian BP profile in patients with essential hypertension. MATERIAL AND METHODS: The study population consisted of 81 essential hypertensive out-patients. BP dipping was defined as a night-to-day systolic and diastolic decrease >/=10%. Forty-seven dipper and 34 nondipper patients were compared. High sensitivity C-reactive protein (hs-CRP), sCD40L and urinary albumin were measured. Brachial artery flow-mediated dilatation (FMD) and cIMT was compared between the groups. RESULTS: sCD40L level (3.28 +/- 2.08 and 2.30 +/- 1.99 ng/ml, respectively, P = 0.036) and urinary albumin concentration (36.7 +/- 20.1 and 23 +/- 29.7 mg/l, respectively, P < 0.0001) were higher in nondippers than in dippers. Serum hs-CRP levels were not significantly different. FMD was found higher in dippers than nondippers (11.8 +/- 3.9% and 6.6 +/- 2.2%, respectively, P < 0.0001). The average cIMT was significantly higher in nondippers than dippers (0.928 +/- 0.060 Vs. 0.734 +/- 0.134 mm; P < 0.0001). CONCLUSIONS: Nondipper patern has an additional negative effect on endothelial functions in hypertensive patients. Nondippers have enhanced sCD40L levels, which may contribute to their increased susceptibility to develop vascular damage.

Alioglu E, Turk UO, Bicak F, Tengiz I, Atila D, Barisik V, Ercan E, Akin M.

Department of Cardiology, Central Hospital, Izmir, Turkey, dreminalioglu@yahoo.com.

Balloon valvuloplasty of aortic valve stenosis in childhood: early and medium term results.

BACKGROUND: Isolated aortic valve stenosis in childhood is treated by balloon valvuloplasty. The role of independent risk factors for the outcome remains unclear. MATERIAL AND METHODS: We analysed the early and medium term outcome of balloon valvuloplasty in isolated aortic valve stenosis in 44 pediatric patients with isolated, severe aortic valve stenosis at an age younger than 18 years, who received a primary balloon valvuloplasty during the last 5 years in our institution. We evaluated the type of aortic valve morphology, age, clinical status, and myocardial function at the time of the intervention as independent risk factor. RESULTS: A significant early relief of the pressure gradient across the aortic valve (P < 0.001) after balloon valvuloplasty was found. This was independent of the aortic valve morphology. Two neonates with a highly stenotic tricuspid aortic valve and severely compromised haemodynamics died within the first 30 days after the intervention. During medium term follow up (mean 22.5 months) we observed a functional deterioration for the stenosis as well as for the insufficiency of the aortic valve. \”Symptoms before intervention\” is an independent risk factors (P < 0.001) for valvuloplasty failure. Patients at an \”age at intervention </= 28 days\” (P = 0.02) and patients with \”reduced myocardial systolic function\” (P = 0.01) had a shorter time to reintervention. CONCLUSIONS: The type of aortic valve morphology only has a weak predictive value for the outcome of balloon valvuloplasty during medium term follow up. Critical ill neonates with an impaired myocardial function are at a higher risk for valvuloplasty failure.

Knirsch W, Berger F, Harpes P, Kretschmar O.

Division of Paediatric Cardiology, University Children’s Hospital Zurich, Steinwiesstrasse 75, 8032, Zürich, Switzerland, walter.knirsch@kispi.uzh.ch.