Purine metabolism: determination of adenyl deaminase in human lymphocytes

Adenylic acid (AMP) deaminase is a "catabolic enzyme" involved in nucleotide degradation, transforming AMP into inosinic acid (IMP). We present a simple method for the determination of the enzyme activity, which combines high sensitivity with requirement of low quantities of lymphocytes. Human lymphocytes were isolated with a Lymphocyte Separation Medium from FLOW and sonicated. After centrifugation at 2,000 rpm x 10 min and treatment with Norit A, the cells were incubated at 37 degrees C with ATP 0.8 mM and 14C-AMP 0.1 mM (specific activity 12 microCi/mumole) in potassium phosphate 100 mM (pH 7.4). 14C-IMP and 14C-AMP were separated through HPLC by an isocratic elution, with 20 mM KH2PO4 (pH 5.5) at a 1.5 ml/min flow rate. Identification of the nucleotides was carried out through retention time, coelution with internal standards: their evaluation by determining the radioactivity of the collected peaks. The enzyme activity is decreased in patients affected by CLL: the decrease is evident only when data are referred to the single cells and not when they are referred to the protein.     

Unusually high rates of metabolism of DHT in cytosols of the quail uropygial gland

The metabolism of DHT in the cytosol of the quail uropygial gland was found to be so high that the steroid was almost completely inactivated within 2 hours of incubation at 0 C. In these conditions, DHT cannot be used for the characterization of androgen receptors. By contrast, R 1881 and mibolerone, which are not metabolized, can be used as alternative ligands. Moreover, the extremely high metabolism of DHT questions the physiologic role of this steroid in the quail uropygial gland.     

Genetic structure of the population of Sicily.

Genetic heterogeneity within Sicily was investigated on the basis of ACP1, ADA, ESD, GLO1, PGD, PGM1, PGM2, SODA, ABO, and MN gene frequencies, and compared to those of other regions of Italy for which these same loci have been examined. Correspondence analysis revealed no differences within the island, at least at the provincial level, but showed genetic differentiation among Italian regions, distinctly clustering northern, central, and southern populations, respectively. These data indicate a close relationship between Sicily and southern Italy. In addition, the contribution of Middle Eastern populations to the gene pool of Sicily was evident.     

Do synapsin I and microtubule-associated proteins bind to a common site on polymerized tubulin?

Synapsin I plays an important role in the regulation of neurotransmitter release, since it binds to synaptic vesicles and to the cytoskeleton, and it bundles F-actin and microtubules. We have previously shown by tryptic digestion of synapsin I that a 44 kDa fragment contains a binding site for polymerized tubulin. In the present experiments, we test whether synapsin I and microtubule-associated proteins (MAPs) have the same or a different binding site on tubulin molecules. Our results show that heat stable MAPs do not compete with synapsin I for binding to taxol tubulin. In addition, subtilisin digestion of tubulin, which suppresses MAPs binding, does not abolish synapsin I cosedimentation with taxol tubulin. Thus, our results strongly suggest that synapsin I (as reported for kinesin) does not bind to the 4 kDa subtilisin digested C-terminal part of the tubulin molecule.     

Form changes in the sea bass, Dicentrarchus labrax (Moronidae: Teleostei), after acclimation to freshwater: an analysis using shape coordinates

Synopsis Morphological changes in the sea bass, Dicentrarchus labrax (Perciformes: Moronidae), were investigated after an experimental acclimation trial to freshwater. The sea bass is an euryhaline species occurring in the Mediterranean and west Atlantic from 30° N to 55° N. Part of the offspring of a pool of breeders was acclimated to freshwater at 9 months of age while maintaining the original stock in marine water. The effect of acclimation to freshwater over the entire form of the fish was studied through geometric morphometrics (shape coordinates). Changes in the form were shown graphically as landmark displacements though age classes 7,12, 15, 19 and 24 months and were discussed in the light of integrated growth. A significantly faster growth in freshwater was detected. Shape coordinates analyzed through multivariate statistics show that significant differences in shape arise after acclimation to freshwater. Moreover, the uniform component of shape change reveals a major effect of stretching or compression perpendicular to the body axis which is common and conservative in both trials. Differences are discussed in terms of selection and ecophenotypism.     

Aerobiological monitoring for fungal spores in a rehabilitation hospital in Northern Italy

In the setting of an aerobiological study of confined environments and environmental prevention of nosocomial infections, aerobiological monitoring of 22 areas in Montescano Medical Rehabilitation Centre (Pavia) was performed in three different months: February, May, and August, 1994. A Lanzoni 3000 spore trap was used for the monitoring. Examination of the results showed that, in the environments monitored, the indoor presence of fungi increased progressively over the three periods considered. The behaviour of individual genera of fungi differed. In the winter periodPenicillium andAspergillus were the most commonly encountered genera.Cladosporium was the dominant genus from the spring to the summer while the yeasts had their maximum counts in the spring morning. The use of air conditioning, combined with the low air exchange between outdoors and indoors in some of the environments certainly played a part in the low concentrations of these latter aerofungi.