Ribulose diphosphate carboxylase activities in cold-resistant common mallow, Malva neglecta Wallr. and a cold-sensitive tomato, Lycopersicon esculentum L., Ace 55 var.

Common mallow ( Malva neglecta Wallr.) and tomato ( Lycopersicon esculentum L. var. Ace 55) were compared as to certain characteristics: Co 2 fixation properties, ribulose diphosphate carboxyl activities, (RuDPCase) photosynthesis, respiration, and compensation points. Significant differences in these factors were observed in all cases except dark respiration. Mallow enzyme (RuDPCase) activities were higher per unit of enzyme than those of tomato. The Mallow RuDPCase exhibited slightly higher activity at 5 to 25 C. Mallow leaves retained their capacity for photosynthesis and respiration after long periods of exposure to subfreezing temperature. The cold adapted mallow had a higher CO 2 compensation point, suggesting a lower efficiency for CO 2 fixation. The results suggest that cold acclimation in common mallow affects photosynthesis but has little effect on respiration.     

Rat sternothyroid muscle: Dissection and preparation for electrophysiologic and electronmicrographic studies

Summary The sternothyroid muscle of the rat is described. The ease of dissection and localization of end-plate regions within the sternothyroid muscle by direct visualization of nerve supply provides a convenient mammalian muscle preparation for electrophysiological and ultrastructural research.This research was supported in part by the following grants: PHS 5429-16-20 (to C. M. Poser), NIH grant NS-07740 (to R. L. Parsons).We express our appreciation to Drs C. M. Poser and R. L. Parsons for providing us with laboratory space and equipment to conduct these experiments in addition to much helpful advice and criticism.     

Multiple hemoglobins in birds

Zusammenfassung Papierelektrophorese des Hämoglobins von zwanzig Vogelarten aus vier verschiedenen Ordnungen ergab zweiteilige Diagramme. Nur bei der Taube ist das Hämoglobin einheitlich, während sonst ziemlich allgemein in der Klasse der Aves zwei Komponenten nachweisbar sind.

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Approved by the Washington Agricultural Experiment Stations for publication. The investigation reported herein was supported, in part, from funds provided for biological and medical research by the State of Washington Initiative Measure No. 171.     

Average conditional correlation and tree structures for multivariate GARCH models

We propose a simple class of multivariate GARCH models, allowing for time‐varying conditional correlations. Estimates for time‐varying conditional correlations are constructed by means of a convex combination of averaged correlations (across all series) and dynamic realized (historical) correlations. Our model is very parsimonious. Estimation is computationally feasible in very large dimensions without resorting to any variance reduction technique. We back‐test the models on a six‐dimensional exchange‐rate time series using different goodness‐of‐fit criteria and statistical tests. We collect empirical evidence of their strong predictive power, also in comparison to alternative benchmark procedures. Copyright © 2006 John Wiley & Sons, Ltd.     

Common variants at 6q22 and 17q21 are associated with intracranial volume

During aging, intracranial volume remains unchanged and represents maximally attained brain size, while various interacting biological phenomena lead to brain volume loss. Consequently, intracranial volume and brain volume in late life reflect different genetic influences. Our genome-wide association study (GWAS) in 8,175 community-dwelling elderly persons did not reveal any associations at genome-wide significance (P < 5 × 10(-8)) for brain volume. In contrast, intracranial volume was significantly associated with two loci: rs4273712 (P = 3.4 × 10(-11)), a known height-associated locus on chromosome 6q22, and rs9915547 (P = 1.5 × 10(-12)), localized to the inversion on chromosome 17q21. We replicated the associations of these loci with intracranial volume in a separate sample of 1,752 elderly persons (P = 1.1 × 10(-3) for 6q22 and 1.2 × 10(-3) for 17q21). Furthermore, we also found suggestive associations of the 17q21 locus with head circumference in 10,768 children (mean age of 14.5 months). Our data identify two loci associated with head size, with the inversion at 17q21 also likely to be involved in attaining maximal brain size.     

Recurrent mutations in the U2AF1 splicing factor in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are hematopoietic stem cell disorders that often progress to chemotherapy-resistant secondary acute myeloid leukemia (sAML). We used whole-genome sequencing to perform an unbiased comprehensive screen to discover the somatic mutations in a sample from an individual with sAML and genotyped the loci containing these mutations in the matched MDS sample. Here we show that a missense mutation affecting the serine at codon 34 (Ser34) in U2AF1 was recurrently present in 13 out of 150 (8.7%) subjects with de novo MDS, and we found suggestive evidence of an increased risk of progression to sAML associated with this mutation. U2AF1 is a U2 auxiliary factor protein that recognizes the AG splice acceptor dinucleotide at the 3' end of introns, and the alterations in U2AF1 are located in highly conserved zinc fingers of this protein. Mutant U2AF1 promotes enhanced splicing and exon skipping in reporter assays in vitro. This previously unidentified, recurrent mutation in U2AF1 implicates altered pre-mRNA splicing as a potential mechanism for MDS pathogenesis.