We investigated the effects of ethanol exposure on the shape of the cell and the morphology of intermediate filaments (IF) of cortical astrocytes in primary culture. The content and distribution of glial fibrillary acidic protein (GFAP), the major component of glial IF, was assessed using an anti-GFAP monoclonal antibody and fluorescence scanning densitometry together with quantitative pre- and post-embedding immunogold electron microscopy. The astrocytes were from 21-day-old fetuses obtained from both control and chronic alcoholic rats and were cultured for 28 days in the absence or presence of ethanol (25 mM). The main findings were: (a) ethanol-exposed astrocytes failed to develop processes or to acquire a filamentous IF distribution pattern; (b) these cells showed less GFAP than astrocytes without alcohol; (c) ethanol interfered with the reorganization of the anti-GFAP binding sites from clustered to random; and (d) astrocytes from alcohol-exposed fetuses cultured in the absence of ethanol also showed these alterations, suggesting initial damage to astrocyte precursor cells. Since the glial filaments play a crucial role in creating a scaffolding that guides neuronal migration, the effect of ethanol on astrocyte IF may possibly be correlated with the mechanisms underlying mental retardation and motor dysfunction which are characteristics of fetal alcohol syndrome.

No abstract

A total of 132 moderately halophilic bacteria were isolated from hypersaline soils with a C1-content between 2-36 and 12.72% (w/v) located near Alicante (S.E. Spain) and examined for 98 phenotypic characteristics including their response to cytological, physiological, biochemical and nutritional tests. They were submitted to a numerical analysis together with six reference strains using both simple matching (SsM) and Jaccard (S,) coefficients, and cluster analysis was carried out by the unweighted pair group method of association (UPGMA), single linkage and complete linkage. With the S, coefficient and UPGMA clustering, eight phenons were obtained at the 65% similarity level. From each phenon representative strains were chosen for the determination of DNA base composition and for electron microscopy. Bacteria belonging to phenons D, E, and F were assigned to the genus Alcaligenes. Phenon G included 27 strains assigned to Acinetobacter, but the high G + C composition (58.9 mol%) of a representative strain of this phenon suggests that it may represent a new taxon. Phenons A, B, and C were designated Flavobacterium and phenon H was Pseudomonas. The bacteria found in these environments are not related to those from hypersaline waters or normal soils.

Astrocyte and glial-neuron interactions have a critical role in brain development, which is partially mediated by glycoproteins, including adhesion molecules and growth factors. Ethanol affects the synthesis, intracellular transport, subcellular distribution and secretion of these glycoproteins, suggesting alterations in glycosylation. We analyzed the effect of long-term exposure to low doses of ethanol (30 mM) on glycosylation process in growing cultured astrocytes in vitro. Cells were incubated for short (5 min) and long (90 min) periods with several radioactively labeled carbohydrate precursors. The uptake, kinetics and metabolism of these precursors, as well as the radioactivity distribution in protein gels were analyzed. The levels of GLUT1 and mannosidase II were also determined. Ethanol increased the uptake of monosaccharides and the protein levels of GLUT1 but decreased those of mannosidase II. It altered the carbohydrate moiety of proteins and increased cell surface glycoproteins containing terminal non-reduced mannose. These results indicate that ethanol impairs glycosylation in rat astrocytes, thus disrupting brain development.

Endocytosis is required for many cellular pivotal processes, including membrane recycling, nutrient uptake, and signal transduction. This complex process is particularly relevant in polarized cells, such as neurons. Previous studies have demonstrated that alcohol alters intracellular traffic, including endocytosis, in several cell types. However, information on the effect of chronic alcohol exposure on this process in neurons is scarce. As an approach, we investigated the effect of alcohol exposure on the internalization of two widely used endocytic markers, albumin and transferrin, in developing hippocampal neurons in primary culture. The effect of this treatment on the levels of several representative proteins involved in the endocytic process was also analyzed. Some of these proteins are also involved in the organization of the actin cytoskeleton. Pretreatment of cells with inhibitors chlorpromazine or nystatin indicates that albumin is internalized mainly by caveolin-dependent endocytosis. On the other hand, alcohol decreases the endocytosis of both markers, although no qualitative changes in the distribution of either of these molecules were observed. Finally, the effect of ethanol on the proteins analyzed was heterogeneous. Alcohol decreases the levels of clathrin, AP-2, SNX9, Rab5, Rab11, EEA1, Cdc42, or RhoA but increases the amount of Arf6. Moreover, alcohol does not affect the levels of caveolin1, dynamin1, Rab7, and LAMP2. This toxic effect of alcohol on endocytosis could affect some of the important neuronal activities, which depend on this process, including cell signaling. Our results in neurons also stress the notion that one of the main targets of ethanol is intracellular transport.