In many prokaryotes and eukaryotes, DNA methylation at cis-regulatory sequences determines whether gene expression is on or off. Stable inheritance of these expression states is required in bacterial pathogenesis, cancer and developmental pathways1,2. Here we delineate the factors that control the stability of these states by using the agn43 gene in Escherichia coli as a model system. Systemati...

1. When is it true? (5 points for each correct answer, -3 point for each wrong answer, 0 point for each blank) Fill in each blank with “always,” “sometimes,” or “never.” For example, • A nonsingular matrix is always invertible. • A square matrix is sometimes full-rank. • A strictly tall matrix is never onto. Here the matrix dimensions are such that each expression makes sense, but they are othe...

there is strong evidence demonstrating that nifedipine dissolved in ethanol selectively inhibits only l-type ca2+ current. in addition, acute ethanol exposure reduces voltage-dependent calcium currents. in the present study, we investigated the antagonistic effect of fixed concentration of nifedipine dissolved in different concentration of ethanol on l-type ca2+ current. in a na+-k+ free soluti...

False mildew is a serious disease of safflower crops in the Yaqui Valley, Mexico, and is caused by infection with a fungus belonging to the genus Ramularia. In the present study, a fungus isolated from leaf lesions was grown under different growth conditions in order to study its mycelial growth and spore production, determining that the solid medium of Septoria tritici at 18 °C of incubation a...

Results from clinical studies suggest that pregnancy alters hepatic drug metabolism in a cytochrome P450 (P450) isoform-specific manner, and rising concentrations of female hormones are potentially responsible for the changes. The objective of this study was to comprehensively characterize the effects of estrogen and progesterone on the expression and activity of major drugmetabolizing P450s. T...

We have demonstrated previously that glucose activates the multifunctional Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) in isolated rat pancreatic islets in a manner consistent with a role of this enzyme in the regulation of insulin secretion [Wenham, Landt and Easom (1994) J. Biol. Chem. 269, 4947-4952]. In the current study, the muscarinic agonist, carbachol, has been shown to ...

(c) Columns of A are independent. (d) A is tall (i.e., n ≤ m) and full-rank (i.e., rank(A) = min(m,n) = n). Solution: We will show the chain of equivalences (a) =⇒ (b) =⇒ (c) =⇒ (d) =⇒ (a). (a) =⇒ (b): By the rank–nullity theorem, we have dim(N (A)) + rank(A) = n, which implies rank(A) = n (since dim(N (A)) = 0). Since rank(A) = rank(A ), we then have rank(A ) = n. Since rank is equivalent to t...

Ecotourists appreciate nature and are willing to learn about nature and ecology. Th erefore ecotourism is often seen as a product package that supports sustainable tourism development. Th is study contributes to existing research in the fi eld of ecotourism as it investigates how travel motives and environmental concern of mountain tourists infl uences their actual demand for ecotourism. A surv...