A B lymphocyte surface molecule mediating activation and protection from apoptosis via calcium channels

A rat mAb (NIM-R5) was prepared against a 42-kD B cell activation Ag (p42). The expression of p42 is increased upon activation. NIM-R5 induces an increase of intracellular Ca2+, due to influx from the exterior milieu via calcium channels. This stimulation does not prejudice further stimulation with anti-Ig, and thus p42 constitutes an activation signal independent of membrane Ig. The antibody induces increased expression of class II molecules on resting B lymphocytes and prepares the cells for "spreading" when interacted with immobilized anti-class II antibody. The antibody alone is weakly mitogenic and comitogenic with IL-4 on resting B cells. Of particular interest, NIM-R5 induces proliferation and rescue from apoptosis in B cells activated in vitro. In conclusion, NIM-R5 induces an Ig-independent activation and proliferation of resting and activated B cells. This antibody does not recognize other known B cell activation Ag such as CD23, CD40, or CD72. We therefore propose that the p42 Ag is a glycoprotein with an important role in the regulation of B lymphocyte activation and survival.

Alpha-2-HS-glycoprotein gene frequencies in Galicia: further evidence for a cline in European populations

alpha 2-HS-glycoprotein (AHSG) phenotypes were determined in 506 unrelated autochthonous individuals from the Galician population (NW Spain) by means of isoelectric focusing followed by silver stain immunofixation. The phenotype frequency distribution fitted with the Hardy-Weinberg law. No evidence of intrapopulation heterogeneity was observed. The allele frequencies obtained were: AHSG*1 = 0.7559 +/- 0.013 and AHSG*2 = 0.2441 +/- 0.013. Our findings lend support to the hypothesis of an AHSG gene frequency cline in European populations. Other population genetics' considerations have also been discussed.

Formal and population genetic studies of AHSG: further data from Galicia

A sensitive immunodetection method for Alpha-2-HS glycoprotein (AHSG) after ultrathin layer polyacrylamide gel isoelectric focusing has been applied to a family study of 126 matings including 292 offspring. Formal genetic studies are in agreement with an autosomal mode of inheritance for this system. A population study of 506 unrelated individuals from Galicia (NW Spain) gave the following frequencies: AHSG*1 = 0.7559 and AHSG*2 = 0.2441, which correspond to a exclusion chance for non-fathers of 0.1505.

Uveomeningoencephalitis in a human immunodeficiency virus type 2-seropositive patient

A 35-year-old woman developed longstanding uveitis and later a uveomeningoencephalitis of unknown origin and died of toxoplasmal brain abscesses. The presence of immunological impairment, human immunodeficiency virus type 2 (HIV-2) seropositivity, and multinucleated cells in the brain led us to suspect neurotropic properties for HIV-2 similar to those of HIV-1.

Nutrient experiment using Phaeodactylum tricornutum as an assay organism

The growth of Phaeodactylum tricornutum, cultured at 7,000 lux and 25º C, in twelve-day experiments using enriched water collected at the surface and 50.0 m depth from coastal waters offshore of Ubatuba area, was carried out. Different water enrichements were made by the aseptic addition of several nutrients, at each depth, according to Smayda (1964). The nitrogen out measured in terms of Carbon-14 assimilation and cloropyll concentration, was found to be a primary limiting factor for marine phytoplankton production.

Plankton studies in a mangrove environment: VII. size fractionation of the phytoplankton: some studies on methods

A series of experiments on the different methods of measuring the relative uptake of C14, by the various size fractions of the phytoplankton, were carried out in a mangrove swamp of the estuarine type at 25º south latitude. As a complement, some factors which might influence the relative uptake of the different fractions in inshore waters, were studied. These factors are related, mainly, with the increase on the amount of labelled particulate matter during incubation period, the effect of different pressures in the filtration of the size fractions of the phytoplankton, the use of a range of volumes for the incubation of samples, and the effect of formalin on the fixation of samples, after the incubation period. Based on these results, some suggestions are made for the use of the C14 method in inshore waters.

Plankton studies in a mangrove environment: IV. size fractionation of the phytoplankton

The seasonal variation of the different fractions of photosynthesizing phytoplankton, measured by C-14 uptake, was studied in a mangrove swamp region, at 25º south latitude. The data showed that the fraction with size range from 5 µ, to 65 µ, was responsible for an average of 61.80% of C-14 uptake of the phytoplankton, during one year, samples having been taken every other month, and showed little seasonal variation when compared with the fraction larger than 65 µ. The results presented here, confirmed general conclusions of other authors, and provided a back-ground for future investigation in the area.

Plankton studies in a mangrove environment II: the standing stock and some ecological factors

This work was undertaken to obtain information on seasonal variation of the plankton communities of the Cananéia mangrove system. The results provide a background for further investigations on primary and secondary productivity and the study of the interrelationships of ecological factors that affect the distribution and abundance of plankton. The correlation of data obtained shows that in the mangrove system under study there are different environments with distinct species.

Relative rates of photosynthesis and standing stock of the net phytoplankton and nannoplankton

Some experiments on C-14 uptake and cell numbers were made with the purpose of comparing nannoplankton and net phytoplankton from surface sea-water samples collected at six stations in Equatorial waters (Fig. 1). The results of these experiments showed a pronounced difference between nanno and net phytoplankton in photosynthesis and in cell numbers (Table I). The net phytoplankton represents an average of as little as 9.93% of total photosynthesis and 22.20% in numbers of organisms of total phytoplankton. The results obtained in coastal and in oceanic waters show that the effect of the proximity of land on standing stock and upon primary production is well marked (Table II). The results obtained are discussed and compared with data of earlier papers.