Immunoquantitation of rat erythrocyte superoxide dismutase: Its use in copper deficiency

Two immunoassays have been developed for the determination of rat erythrocyte dismutase (Cu,Zn-SOD). An enzyme-linked immunosorbent assay (ELISA) was very sensitive down to 4 ng/ml with a coefficient of variation (CV) of 18% while the single radial immunodiffusion assay (SRID) permitted an adequate detection level (5 μg/ml) with far better accuracy (CV = 4.2%). The latter was thus selected for the determination of Cu,Zn-SOD in the red blood cells of normal and copper-depleted rats. The average value of Cu,Zn-SOD in normal adult rat erythrocytes was 1142 ± 120 ng/mg hemoglobin. When compared to activity measurements, good correlation was obtained between enzyme content and enzyme activity (r = 0.803, P < .001). In an experimental copper deficiency followed by supplementation, good correlation was observed in the course of depletion (r = 0.848, P < .001) and repletion (r = 0.896, P < .001). During depletion, the loss of enzyme activity was mainly related to a loss of enzyme. However, enzymatically inactive protein was formed which would be activated when copper was added. These results indicate the importance of a combined use of Cu,Zn-SOD immunoquantitation and activity measurements to enable a better understanding of changes occuring with respect to enzyme activity.     

Characterization of Isoforms of Pectin Methylesterase of Linum usitatissimum Using Polyclonal Antibodies

In flax (Linum usitatissimum, c.v. Ariane) pectin methylesterase(PME) (EC 3.1.1.11 [EC] ), ionically bound to cell-wall, was composedmainly of forms with isoelectric points (pIs) of 7.1, 7.6 and9.6. Minor forms, with acid pIs (4.5, 4.8 and 6.3), were detectedduring the purification of two of these forms. Polyclonal antibodieswere raised against the isoenzymes presenting pIs of 7.1 and7.6. Antibodies recognized antigenic forms and two close proteinsin the basic range which could be associated to the PME activitywith pI of 9.6. Antibodies did not recognize any acid formsand exhibited no cross-reactivity with proteins resolved inthe cellular content. Antigenicity was related mainly to theprotein part of the glycosylated enzyme. The antibodies againstflax PME did not cross-react with PMEs from Citrus and tomatoand with glycosylated proteins of various sources. Specificityof anti-PME antibodies was judged sufficient to localize therecognized forms on tissue prints of flax hypocotyls. AlthoughPME was distributed in the whole parts of hypocotyl, stainingwas not homogeneous and appeared reinforced in the apical zone.In the basal part, epidermis was more contrasted than internaltissues. (Received August 2, 1994; Accepted January 3, 1995)     

Résultats préliminaires des sites subfossiles d’Antsingiavo (Madagascar)

Preliminary report on Antsingiavo subfossils sites (Madagascar). Two new sites, Antsingiavo A & B, have been discovered in the Narinda peninsula, situated in the North-West of Madagascar, Province of Mahajanga. Breccias contain microfauna associated with subfossil lemurs of an average size (Archaeolemur) and small (Microcebus). Until now, the subfossil microfauna of Madagascar was practically unknown. The sample from Antsingiavo offers information on past environments in the Narinda peninsula. The new discoveries contribute to an understanding of the diversity Archaeolemur, with different forms in the different areas of Madagascar. To cite this article : D. Gommery et al., C. R. Palevol 2 (2003).