Hormone regulated enzyme activities of plasma membrane of decidual endometrium of the rat

Plasma membranes were purified from deciduoma of pseudopregnant rats and rat liver. Preparations contained 80% plasma membrane-derived material as based on electron microscope morphometry and analysis of enzyme markers. Several plasma membrane enzymes were tested for direct response to hormones. NADH-ferricyanide reductase of plasma membranes from both tissues was stimulated by glucagon and inhibited by insulin but was unresponsive to steroids. For steroids, responsiveness was limited to a reduction in NaF-stimulated adenylate cyclase activity by the steroid R5020. Thus, interaction of steroid hormones with plasma membranes, unlike that of glucagon and insulin, is not reflected in an altered activity of plasma membrane-bound dehydrogenases but may be exerted directly on adenylate cyclase.     

FGFR2 exon IIIa and IIIc mutations in Crouzon, Jackson-Weiss, and Pfeiffer syndromes: evidence for missense changes, insertions, and a deletion due to alternative RNA splicing.

Fibroblast growth factor receptor 2 (FGFR2) mutations have been associated with the craniosynostotic conditions Crouzon, Jackson-Weiss, and Pfeiffer syndromes. Previously, mutations were described in the exons IIIa and IIIc, which form the extracellular, third immunoglobulin-like domain (IgIII) and adjacent linker regions, both of which are normally involved in ligand binding. For all three conditions, mutations were found in exon IIIc. Only in Crouzon syndrome were mutations identified in exon IIIa. In this study, 39 cases with one of these three conditions were screened for exon IIIa or IIIc mutations. Eleven mutations are reported in 17 unrelated cases. Mutations in exon IIIa are identified for not only Crouzon but also Jackson-Weiss and Pfeiffer syndromes. Four mutations in either exon IIIa or exon IIIc reported only in Crouzon syndrome are present also in one of the other two syndromes. Two insertions, one in exon IIIa in a Crouzon syndrome patient and the other in exon IIIc in a Pfeiffer syndrome patient, were observed. The latter mutation has the same alternative RNA splicing effect as a reported synonymous mutation for Crouzon syndrome. A missense mutation was detected in one Pfeiffer syndrome family in which two members had craniosynostosis without limb anomalies. The inter- and intrafamilial variability in expression of FGFR2 mutations suggests that these three syndromes, presumed to be clinically distinct, are instead representative of a spectrum of related craniosynostotic and digital disorders.     

Identification of Products from Oxidation of Uric Acid Induced by Hydroxyl Radicals

The aim of the present study was to separate and characterise products formed by oxidation of uric acid by hydroxyl radicals with a view to probing for these products in vivo in clinical contexts. Aerated solutions of 200 μM uric acid, or its oxidation products, allantoin or parabanic acid, were exposed to gamma radiolysis, (52.0 Gy/min), as a source of HO- radicals, at pH 3.4 and 7.4. Aliquots were taken every 5 minutes for 20 minutes and oxidation products were separated by HPLC and analysed with a diode array detector. Identities of oxidation products were confirmed on the basis of similarity of retention times and absorbance spectra and peak purity parameters of known standards. Hydroperoxides were measured by tri-iodide formation in the 20 minute sample. Exposure of uric acid to such HO fluxes produced a net loss of the parent compound with formation of a complex mixture of products with allantoin and parabanic acid being the predominant products at pH 3.4. The rate of uric acid degradation at physiological pH was slower and the distribution of oxidation products was different. A small but significant amount of uric acid hydroperoxide was detected at both pHs. A mechanism for uric acid oxidation under these conditions is presented.     

Dextran production by Leuconostoc mesenteroides in the presence of a dextranase producing yeast, Lipomyces starkeyi

Summary A new process for the production of small size dextran is developed in which dextran is produced by cultures of Leuconostoc mesenteroides in the presence of a partially constitutive mutant of Lipomyces starkeyi producing dextranase. Mixed cultures were examined by scanning electron microscopy with ruthenium to show the effects of the mixed culture on low molecular weight dextran (M.W. of 5,000 – 100,000) formation. The presence of the size variation in dextran was confirmed by gel permeation chromatography.     

Immobilization of tyrosinase for use in nonaqueous media: Enzyme deactivation phenomena

Summary We have investigated features for minimizing the inactivation of tyrosinase (E.C. 1.14.18.1) that is caused by immobilization on glass beads and Celite^®. The degree of inactivation is dependent on the enzyme loading and the carrier's surface area. Addition of a sacrificial protein during the immobilization procedure offers a protective effect with increased residual activity on the basis of comparable enzyme loading.     

Slide staining device for use during space flight.

A slide staining device is described that performs Gram and Wright stains during space flight. Reagents and liquid wastes are contained within a closed system.