materials and methods total protein was determined by lowery method. bovine lens alr2 was partially purified by gel filtration chromatography on sephadextm g25. bovine cortex kidney alr1 was partially purified by diethylaminoethyl (deae) precipitation. the hydroalcoholic extract was obtained from frozen propolis. the enzyme activity and sorbitol accumulation in erythrocytes were determined spec...

In cerebrospinal fluid of patients with cerebral infections, elevated concentrations of the pteridine compounds neopterin and 7,8-dihydroneopterin were detected. Here, the potential of pteridines to induce apoptosis of the rat pheochromocytoma cells (PC12) was investigated. In contrast to aromatic pteridines like neopterin, the reduced forms 7,8-dihydroneopterin, 5,6,7,8-tetrahydrobiopterin and...

Background. The age of an insect strongly influences many aspects of behavior and reproduction. The interaction of age and behavior is epitomized in the temporal polyethism of honey bees in which young adult bees perform nurse and maintenance duties within the colony, while older bees forage for nectar and pollen. Task transition is dynamic and driven by colony needs. However, an abundance of p...

The chloroform-soluble pigments of various pseudomonads have been found to be phenazine derivatives (Clemo & Daglish, 1950; Hillemann, 1938; Kogl & Postowsky, 1930; Kluyver, 1956; Haynes et al. 1956), whereas the constitutions of water-soluble fluorescent pigments of various pseudomonads are not well known. This has been mainly due to the failure of previous attempts to obtain the pigments in a...

The fine structure and the composition of pteridine pigments of erythrophores in adults of the swordtail fish, Xiphophorus helleri, were studied by means of cytochemistry, paper chromatography, ionophoresis, centrifugal fractionation, and electron microscopy. It was found that water-soluble pigments of erythrophores consisted exclusively of pteridine derivatives including large amounts of droso...

Leishmania parasites possess an abundance of ether-linked hydrocarbons as components of phospholipids and glycosylphosphatidylinositol anchors of glycoproteins and polysaccharides, including important surface molecules such as lipophosphoglycan (LPG) and glycosylinositolphospholipids (GIPLs). Cleavage of the ether bond is an important feature in the turnover pathway of alkylglycerols. In mammal...

The antitumor compound PT523 [N(alpha)-(4-amino-4-deoxypteroyl)-N(delta)-hemiphthaloyl-L- ornithine] was found to have an inhibition constant (K(i)) of 0.35 +/- 0.10 pM against human dihydrofolate reductase (hDHFR), 15-fold lower than that of the classical antifolate drug methotrexate (MTX). The structure of PT523 bound to hDHFR and hDHFR-NADPH was investigated using multinuclear NMR techniques...