Isolation of the low-molecular-mass form of catechol O-methyltransferase from rat liver and immunocytochemical localization of the enzyme in the glycogen compartment

The low-molecular-mass form of two distinct catechol O-methyltransferase activities (S-adenosyl-L-methionine: catechol O-methyltransferase, COMT, EC 2.1.1.6) has been purified to homogeneity from rat liver using 40-70% ammonium sulfate precipitation, gel filtration on Sephadex G-100, adsorption on hydroxyapatite C and ion-exchange chromatography on DEAE-Sepharose CL-6B. The relative molecular mass Mr, determined by sodium dodecyl sulfate/polyacrylamide gel electrophoresis is 22 400 +/- 500. Irradiation of the enzyme in the presence of 8-azido-[methyl-3H]AdoMet results in the specific labeling of the catalytic site of the enzyme. Photolabeling was successful with crude COMT preparations and with the isolated enzyme. Immunocytochemical studies present new information about the localization of the low-molecular-mass form in the liver parenchyma. Subcellularly COMT immunoreactivity could be attributed exclusively to the compartment with glycogen granules. Nucleus, mitochondria and endoplasmic reticulum showed no immunostaining.     

The Effect of Traffic Density on Lead Contents in Roadside Soils: An Analysis of Published Data

Data from eight published studies were combined to show that the influence of traffic density on Pb contents in roadside soils increases with proximity to the road.     

Breast Feathers as an Air-current Sense Organ for the Control of Flight Behaviour in a Songbird (Carduelis spinus)

Analysis of the flight behaviour of siskins (Carduelis spinus) was made possible by tethering them with a harness to a flight balance in a wind tunnel. It could be shown that the breast feathers work as an air-current sense organ influencing the siskins' flight pattern and the aerodynamic parameters.     

A Three-Dimensional Skeletal Reconstruction of the Stem Amniote Orobates pabsti (Diadectidae): Analyses of Body Mass,Centre of Mass Position,and Joint Mobility

Orobates pabsti, a basal diadectid from the lower Permian, is a key fossil for the understanding of early amniote evolution. Quantitative analysis of anatomical information suffers from fragmentation of fossil bones, plastic deformation due to diagenetic processes and fragile preservation within surrounding rock matrix, preventing further biomechanical investigation. Here we describe the steps taken to digitally reconstruct MNG 10181, the holotype specimen of Orobates pabsti, and subsequently use the digital reconstruction to assess body mass, position of the centre of mass in individual segments as well as the whole animal, and study joint mobility in the shoulder and hip joints. The shape of most fossil bone fragments could be recovered from micro-focus computed tomography scans. This also revealed structures that were hitherto hidden within the rock matrix. However, parts of the axial skeleton had to be modelled using relevant isolated bones from the same locality as templates. Based on the digital fossil, mass of MNG 10181 was estimated using a model of body shape that was varied within a plausible range to account for uncertainties of the dimension. In the mean estimate model the specimen had an estimated mass of circa 4 kg. Varying of the mass distribution amongst body segments further revealed that Orobates carried most of its weight on the hind limbs. Mostly unrestricted joint morphology further suggested that MNG 10181 was able to effectively generate propulsion with the pelvic limbs. The digital reconstruction is made available for future biomechanical studies.     

Detection of Aldehydes and Their Conjugated Hydroperox Ydiene Precursors in Thermally-Stressed Culinary Oils and Fats: Investigations Using High Resolution Proton Nmr Spectroscopy

High field (400 and 600 MHz) proton NMR spectroscopy has been employed to investigate the thermally-induced autoxidation of glycerol-bound polyunsaturated fatty acids present in intact culinary frying oils and fats. Heating of these materials at 180°C for periods of 30, 60 and 90 min. generated a variety of peroxidation products, notably aldehydes (alkanals, trans-2-alkenals and alka-2, 4-dienals) and their conjugated hydroperoxydiene precursors. Since such aldehydes appear to be absorbed into the systemic circulation from the gut in vivo, the toxicological significance of their production during standard frying practices is discussed.