Human chromosome 21-derived miRNAs are overexpressed in down syndrome brains and hearts

Down syndrome (DS), or Trisomy 21, is the most common genetic cause of cognitive impairment and congenital heart defects in the human population. To date, the contribution of microRNAs (miRNAs) in DS has not been investigated. Bioinformatic analyses demonstrate that human chromosome 21 (Hsa21) harbors five miRNA genes; miR-99a, let-7c, miR-125b-2, miR-155, and miR-802. MiRNA expression profiling, miRNA RT-PCR, and miRNA in situ hybridization experiments demonstrate that these miRNAs are overexpressed in fetal brain and heart specimens from individuals with DS when compared with age- and sex-matched controls. We hypothesize that trisomic 21 gene dosage overexpression of Hsa21-derived miRNAs results in the decreased expression of specific target proteins and contribute, in part, to features of the neuronal and cardiac DS phenotype. Importantly, Hsa21-derived miRNAs may provide novel therapeutic targets in the treatment of individuals with DS.     

Hoechst 33258, distamycin A,and high mobility group protein I (HMG-I) compete for binding to mouse satellite DNA

The experiments described were designed to test the hypothesis that the (A+T)-specific DNA binding ligands Hoechst 33258 and distamycin A affect the condensation of mouse centromeric heterochromatin by competing for binding to satellite DNA with one or more chromosomal proteins. The studies focused on the nonhistone chromosomal protein HMG-I since its binding properties predict it would be a target for competition. Gel mobility shift assays show that HMG-I forms specific complexes with satellite DNA and that the formation of these complexes is competed for by both Hoechst and distamycin. In addition, methidium propyl EDTA Fe(II) [MPE Fe(II)] footprints of ligand-satellite DNA complexes showed essentially the same protection pattern for both drugs and a similar, but not identical, HMG-I footprint. If these in vitro results reflect the in vivo situation then the incomplete condensation of centromeric heterochromatin observed when mouse cells are grown in the presence of either chemical ligand could be a consequence of competition for binding of HMG-I (and possibly other proteins) to satellite DNA.by E.R. Schmidt     

The effects of oxidation on the reverse-phase high-performance liquid chromatography characteristics of the high mobility groups 1 and 2 proteins

Ion-pair reverse-phase high-performance liquid chromatography is a quick and convenient method for obtaining essentially pure preparations of the HMG (high mobility group)-1 and HMG-2 proteins if dithiothreitol is added to the eluted HMG protein fractions to prevent oxidation and their subsequent altered migration on acid-urea polyacrylamide gels. Unexpectedly, we found that this chromatographic separation technique can resolve the oxidized and reduced forms of both HMG-1 and HMG-2 proteins. We show that oxidized HMG-1 and -2 protein subfractions are responsible for some, but by no means all, of the HMG-1 and -2 protein heterogeneity previously reported by Elton and Reeves (2). At least two different HMG-1 protein species (one major and one minor) and at least four different HMG-2 protein species (two major and two minor) are consistently found in fully reduced "enriched" HMG-1 and -2 pig thymus protein preparations.     

Exercise training increases glucose transporter protein GLUT-4 in skeletal muscle of obese Zucker (fa/fa) rats

The present study examined the level of GLUT-4 glucose transporter protein in gastrocnemius muscles of 36 week old genetically obese Zucker (fa/fa) rats and their lean (Fa/-) littermates, and in obese Zucker rats following 18 or 30 weeks of treadmill exercise training. Despite skeletal muscle insulin resistance, the level of GLUT-4 glucose transporter protein was similar in lean and obese Zucker rats. In contrast, exercise training increased GLUT-4 protein levels by 1.7 and 2.3 fold above sedentary obese rats. These findings suggest endurance training stimulates expression of skeletal muscle GLUT-4 protein which may be responsible for the previously observed increase in insulin sensitivity with training.     

Evaluating Archaeological Evidence for Demographics,Abandonment, and Recovery in Late Antique and Byzantine Anatolia

Archaeological evidence, particularly that deriving from systematic regional surveys, offers great potential for understanding social and demographic change in Anatolia between 300 and 1200 CE. We first consider major factors inherent to regional archaeological data sets that complicate simple synthesis and generalization between projects. We then provide a synthesis focused on longue durée questions relevant to cross-disciplinary examination of the relationship between environmental and societal change and examine potential connections between major changes in settlement patterns observed in the seventh- and eighth- century archaeological data and larger questions of systemic collapse and resilience in the face of climate change. To conclude, we assess current archaeological evidence for the processes of agricultural adaptation at the transition associated with the end of the ancient economy.     

Aristolochia zebrina sp. nov. (Aristolochiaceae) from southeastern Brazil

Aristolochia zebrina is described, illustrated and discussed in comparison with the two most similar species, A. papillaris Mast. and A. tamnifolia (Klotzsch) Duch. The new species is distinguished from its relatives mainly by the ellipsoid utricle, the narrowly ovate, revolute, and efimbriate floral limb with dark purple longitudinal stripes inside, and the glabrous and smooth capsules, which are broadly cylindrical. So far, the new species has only been found in ‘restingas’ (sandy soils) and wet tropical Tabuleiro forests in northern Espírito Santo, southeastern Brazil.