Formation of school subjects as curriculum content : patterns and structures
To show that curriculum content is always socially constructed and might be a result of struggling social forces giving way for different interpretations, interpretations that lean on different pol ...
The formation of a school subject and the nature of curriculum content: an analysis of liberal studies in Hong Kong
This essay explores the nature of the curriculum content of liberal studies—a core school subject in the new senior secondary curriculum in Hong Kong—with reference to the curriculum‐making processes entailed in the formation of that subject. The central thesis is that a school subject is introduced to schools and classrooms as a distinct representation of content embodied in curriculum materials, entailing a theory of content—a special way of selecting, organizing, and framing the content for social, cultural, educational, curricular, and pedagogical purposes. Knowing the content of a school subject thus entails knowing more than the content per se; it entails an understanding of the underlying theory of content, which is necessary for disclosing and realizing the educational potential embodied in the content.
ATP-dependent S-(2,4-dinitrophenyl)glutathione transport in canalicular plasma membrane vesicles from rat liver.
Uptake of the thioether S-(2,4-dinitrophenyl)glutathione (DNPSG) in canalicular plasma membrane vesicles from rat liver is enhanced in the presence of ATP and exhibits an overshoot with a transient 5.5-fold accumulation of DNPSG. Stimulation by ATP is not caused by the generation of a membrane potential, based on responses of the indicator dye oxonol V. ATP-dependent uptake has an apparent Km of 71 microM for DNPSG and a Vmax of 0.34 nmol.min-1.mg of vesicle protein-1. Protein thiol groups are essential for transport activity as indicated by the sensitivity of DNPSG transport to sulfhydryl reagents. There is competitive inhibition with other thioethers, S-hexylglutathione (Ki = 66 microM), the photoaffinity label S-(4-azidophenacyl)glutathione (Ki = 56 microM), as well as with glutathione disulfide (Ki = 0.44 mM) and with the bile acid taurocholate (Ki = 0.61 mM). GSH (2 mM) or cholate (0.4 mM) does not inhibit. Both glutathione disulfide and taurocholate show ATP-dependent transport in the canalicular membrane vesicles which is inhibited by DNPSG. No ATP-dependent transport is found for GSH. Transport of DNPSG is also inhibited competitively by alpha-naphthyl-beta-D-glucuronide (Ki = 0.42 mM) but not by alpha-naphthylsulfate (2 mM), and there is substantial inhibition with the glucuronides from ebselen and p-nitrophenol. The results indicate that the canalicular transport system for DNPSG is directly driven by ATP and that the biliary transport of other classes of compounds may also proceed via this system.