The propositional fragment L 1 of Leniewski's ontology is the smallest class (of formulas) containing besides all the instances of tautology the formulas of the forms: (a, b) (a, a), (a, b) (b,). (a, c) and (a, b) (b, c). (b, a) being closed under detachment. The purpose of this paper is to furnish another more constructive proof than that given earlier by one of us for: Theorem A is provable in L 1 iff TA is a thesis of first-order (...) predicate logic with equality, where T is a translation of the formulas of L 1 into those of first-order predicate logic with equality such that T(a, b) = FblxFax (Russeltian-type definite description), TA B = TA TB, T A = TA, etc. (shrink)

The inositol phosphate metabolism network has been found to be much more complex than previously thought, as more and more inositol phosphates and their metabolizing enzymes have been discovered. Some of the inositol phosphates have been shown to have biological activities, but little is known about their signal transduction mechanisms except for that of inositol 1,4,5‐trisphosphate. The recent discovery, however, of a number of binding proteins for inositol high polyphosphate [inositol 1,3,4,5‐tetrakisphosphate (IP4), inositol 1,3,4,5,6‐pentakisphosphate, or inositol hexakisphosphate] enables us to (...) speculate on the physiological function of these compounds. In this article we focus on two major issues: (1) the roles of inositol high polyphosphates in vesicular trafficking, especially exocytosis, and (2) pleckstrin homology domaincontaining IP4 binding proteins involved in the Ras signaling pathway. (shrink)