Yeasts from Marine and Estuarine Waters with Different Levels of Pollution in the State of Rio de Janeiro, Brazil

Yeast counts were made at 24 marine and estuarine sites in the vicinity of Rio de Janeiro, Brazil. Mean salinities of estuarine sites ranged from 14.2 to 27.4‰, and mean temperatures ranged from 25 to 28°C. Total coliform counts varied from 80% above 100,000 colony-forming units (CFU)/100 ml at heavily polluted sites to 100% below 100 CFU/100 ml at unpolluted sites. Total yeast counts above 100 CFU/100 ml were typical of heavily and moderately polluted water but atypical of lightly polluted and unpolluted water. Mean total yeast counts were 2,880 CFU/100 ml for heavily polluted sites, 202 CFU/100 ml for moderately polluted sites, and 3 CFU/100 ml for lightly polluted and unpolluted sites. Total yeast counts had a positive response to increased pollution levels, and Candida krusei and phenotypically similar yeasts as a group were prevalent in polluted estuarine water but rare in unpolluted seawater. The 549 strains of yeasts and yeast-like organisms isolated were grouped into 67 species, of which the 21 most prevalent made up 86% of the total yeast population. The prevalent genera in the polluted estuary were Candida, Rhodotorula, Torulopsis, Hanseniaspora, Debaryomyces, and Trichosporon.     

Complete amino acid sequence of a variant surface glycoprotein (VSG 117) from Trypanosoma brucei

The amino acid sequence of a variant surface glycoprotein (VSG 117) of Trypanosoma brucei has been determined by manual sequencing of tryptic. staphylococcal protease and cyanogen bromide peptides and fragments derived from these peptides. Some overlaps needed for completion of the sequence were deduced from the nucleotide sequence of complementary DNA derived from messenger RNA coding for VSG 117. The glycoprotein consists of 470 amino acid residues with two carbohydrate chains attached at Asn420 and Asp470. No pronounced hydrophobic regions, which are characteristic of many membrane proteins, are present in the isolated glycoprotein, and the carboxy-terminal region, which is close to the membrane, is remarkably hydrophilic. These observations indicate that the molecule probably does not penetrate the lipid bilayer of the plasma membrane. The high proportion of charged residues in the carboxyterminal region is more consistent with electrostatic interaction with the polar head groups of the phospholipids.     

Insulin-induced lipoatrophy: evidence for an immune pathogenesis.

Skin biopsy samples from 14 diabetic patients with lipoatrophy at injection sites and from five insulin-treated diabetic patients without such lipoatrophy (controls) were examined by immunofluorescence for the deposition of immunological components. Also sera from 13 of the patients with lipoatrophy and from all of the controls were assayed for insulin-binding capacity. Biopsy samples from the edge of lipoatrophic areas (eight cases) invariably showed abnormal deposition of immunological components in dermal vessel walls, whereas no such deposition was seen in the control samples. Mean serum insulin-binding capacity was 33.1 microgram/l in the patients with lipoatrophy compared with only 4.6 microgram/l in the controls. These findings suggest that insulin-induced lipoatrophy results from the local formation of immune complexes, complement fixation, and release of inflammatory mediators from the cellular infiltrate.     

BCG-induced granulomatous pulmonary inflammation and splenomegaly in mice: A T-cell-dependent response

When C57BL/6 mice were injected iv with BCG in an oil-in-saline emulsion, they developed intense pulmonary granulomatous inflammation (PGI) and splenomegaly as well as chemotactic activity for macrophages and angiotensin-converting enzyme (ACE) in their lung fluids. PGI, splenomegaly, and levels of chemotactic activity and ACE were markedly reduced in T-cell-deficient “B” mice. The capacity to develop PGI was fully restored and splenomegaly was partially restored in “B” mice by the provision of syngeneic thymocytes, spleen cells, or purified T cells. These results indicate that the full expression of BCG-induced PGI is dependent upon thymus-derived cells and is associated with high levels of chemotactic activity for macrophages and ACE in the lung lavage fluid. Although BCG-induced splenomegaly appears to be T cell dependent, it did not reach its full magnitude in reconstituted “B” mice.     

Cell surface receptors for lymphokines. II. Studies on the carbohydrate composition of the MIF receptor on macrophages using synthetic saccharides and plant lectins.

The carbohydrate composition of the surface receptor for macrophage migration inhibitory factor (MIF) on guinea pig macrophages has been studied by examining the interaction of MIF with different saccharides and by testing the ability of plant lectins with known saccharide binding affinities to bind to macrophages and block their response to MIF. Comparison of the effectiveness of a variety of natural and synthetic mono- and disaccharides in inhibiting MIF activity in lymphocyte supernatants revealed that inhibitory activity was confined to natural 5-methylpentose sugars (l-fucose > l-rhamnose = 6-deoxy-d-glucose) and synthetic saccharides containing α-fucosyl residues. Observations on the MIF inhibitory activity of synthetic fucosyl glycosides containing fucosyl residues of defined configuration at terminal and subterminal positions indicate that MIF interacts preferentially with terminal α-l-fucopyranosyl residues and does not recognize subterminal saccharides. Studies with disaccharides containing α-(1 → 2)-, α-(1 → 3), and α-(1 → 6)-linked l-fucosyl residues failed to reveal preferential interaction of MIF with any one linkage configuration. Incubation of macrophages before exposure to MIF with lectins that bind to terminal fucosyl residues (Lotus tetragonolobus and Ulex europaeus_I, agglutinins) rendered them unresponsive to MIF but lectins which bind to nonterminal fucosyl residues and to other saccharides had no effect. The role of fucosyl residues in the binding of MIF by macrophages is discussed with reference to the possible composition of the MIF receptor and the role of fucose-containing glycolipids as receptors for this lymphokine.