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The study compared the effect of two adaptations of a scientific article on students' comprehension and use of scientific inquiry skills. One adaptation preserved as much as possible the canonical form of the original article (APL, Adapted Primary Literature) and the other was written in a more narrative mode typical of secondary literature (SL). Both adaptations contained the same content. Two hundred and eleven senior high school students in a Western Canadian school district participated. The numbers of males and females were approximately equal, and all students were registered in an introductory calculus course. All students were given a 90 min class by their teachers that introduced them to the basic mathematical concepts needed to read the articles. Students were randomly assigned to read either the APL or the SL and afterwards to complete a questionnaire, which was common to both groups. Major findings showed that the SL students better understood the article, that the APL students thought more critically about the article, that females understood the article better than males, and that students' attitudes towards reading the articles, regardless of group, were positively associated with their comprehension and use of inquiry skills. The results coincide in important ways with those of similar studies in Israel, and show that asking students to read text that resembles scientific writing increases their use of critical thinking skills when reading.

[beta]-Actin, once thought to be an exclusively cytoplasmic protein, is now known to have important functions within the nucleus. Nuclear [beta]-actin associates with and functions in chromatin remodeling complexes, ribonucleic acid polymerase complexes, and at least some ribonucleoproteins. Proteins involved in regulating actin polymerization are also found in the interphase nucleus. We define the dynamic properties of nuclear actin molecules using fluorescence recovery after photobleaching. Our results indicate that actin and actin-containing complexes are reduced in their mobility through the nucleoplasm diffusing at ~0.5 [micro][m.sup.2] [s.sup.-1]. We also observed that ~20% of the total nuclear actin pool has properties of polymeric actin that turns over rapidly. This pool could be detected in endogenous nuclear actin by using fluorescent polymeric actin binding proteins and was sensitive to drugs that alter actin polymerization. Our results validate previous reports of polymeric forms of nuclear actin observed in fixed specimens and reveal that these polymeric forms are very dynamic.

The commonly occurring E23K and I337V Kir6.2 polymorphisms in the ATP-sensitive potassium (KATP) channel are more frequent in Caucasian type 2 diabetic populations. However, the underlying cellular mechanisms contributing to the pathogenesis of type 2 diabetes remain uncharacterized. Chronic elevation of plasma free fatty acids observed in obese and type 2 diabetic subjects leads to cytosolic accumulation of long-chain acyl CoAs (LC-CoAs) in pancreatic beta-cells. We postulated that the documented stimulatory effects of LC-CoAs on KATP channels might be enhanced in polymorphic KATP channels. Patch-clamp experiments were performed on inside-out patches containing recombinant KATP channels (Kir6.2/SUR1) to record macroscopic currents. KATP channels containing Kir6.2 (E23K/I337V) showed significantly increased activity in response to physiological palmitoyl-CoA concentrations (100-1,000 nmol/l) compared with wild-type KATP channels. At physiological intracellular ATP concentrations (mmol/l), E23K/I337V polymorphic KATP channels demonstrated significantly enhanced activity in response to palmitoyl-CoA. The observed increase in KATP channel activity may result in multiple defects in glucose homeostasis, including impaired insulin and glucagon-like peptide-1 secretion and increased glucagon release. In summary, these results suggest that the E23K/I337V polymorphism may have a diabetogenic effect via increased KATP channel activity in response to endogenous levels of LC-CoAs in tissues involved in the maintenance of glucose homeostasis. [ABSTRACT FROM AUTHOR]