Chrysophycean stomatocysts in a Caribbean mangrove

A chrysophyte cyst assemblage from surface sediments of a tropical, brackish-water environment in the southern Caribbean coast is described and depicted. All the cysts are unornamented and relatively large. The taxonomic diversity is low, due probably to human disturbance or salinity stress. It is assumed that the chrysophyte taxa involved are salinity-tolerant, freshwater algae. This is the first record of chrysophyte cysts in mangrove environments, and extends the range of habitats in which they are commonly found.     

Antiprotozoal effects of some hydrazones

Antiprotozoal effects of hydrazones derived from compounds with 1 to 4 carbon atoms were studied on the model organism Trichomonas vaginalis isolated from a female patient with acute urogenital trichomoniasis.     

Preparation of d-galactofuranosyl nitromethanes: a revision and a new approach

Sodium methoxide-promoted methanolysis of 7-deoxy-7-nitro-l-glycero-l-galacto-heptitol peracetate rapidly and nearly quantitatively accumulates 7-deoxy-6-O-methyl-7-nitro-l-glycero-l-galacto-heptitol. The prolonged treatment then provides 76% of d-galactofuranosyl nitromethanes and finally results in the equilibrium of 77% of β-d-galactopyranosyl nitromethane and 7–9% of three other tautomeric d-galactosyl nitromethanes. Thermal treatment of 7-deoxy-7-nitro-l-glycero-l-galacto-heptitol in boiling water peaks at a 58% content of d-galactofuranosyl nitromethanes and ends in a similar equilibrium mixture of four d-galactosyl tautomers. The relevant kinetic parameters of the latter transformation are determined by a curve fitting using the nonlinear least-squares Marquardt–Levenberg algorithm.     

Collagen/hyaluronan membrane as a scaffold for chondrocytes cultivation

Rabbit chondrocytes were cultivated in vitro using the collagen/hyaluronan membrane. The membrane did not show any adverse effects on chondrocyte viability during in vitro cultivation. The inoculated cells grew without any negative changes. According to the histochemical analyses: (i) hematoxylin and eosin; (ii) safranin O; and (iii) rabbit anti-human collagen type II staining, the rabbit chondrocytes maintained their morphology and phenotype during in vitro cultivation. The collagen/hyaluronan membrane became more stable and stiffer after long time cultivation. The proliferation of the chondrocytes stabilised the structure of the membrane. The collagen/hyaluronan membrane is suitable material for the chondrocyte growth and could provide functional tissue-engineered scaffold for cartilage repair.     

Incorporation of mannoproteins into the walls of aculeacin A-treated yeast cells

Inhibition of the synthesis of alkali-insoluble glucan by aculeacin A in Saccharomyces cerevisiae cells caused a decrease in the incorporation of a high molecular weight heterogeneous mannoprotein material and of a 33000 mannoprotein into the wall network. This was concomitant with the excretion of the latter molecule into the growth medium. Regenerating yeast protoplasts liberated considerable amounts of the heterogeneous material to the medium independently of the presence of aculeacin. The protoplast walls did lack this component and contained only minor amounts of the 33000 molecule, which was also completely absent from walls of aculeacin-treated protoplasts. Considerable levels of the 33000 species were immunodetected in the supernatants from treated and untreated protoplasts. These results point to the existence of specific interactions between the glucan network of the yeast cell surface and some of the wall mannoproteins. On the other hand, the presence of a population of SDS-solubilizable mannoproteins in the wall was independent of glucan levels.Abbreviations SDS sodium dodecyl sulphate - YNB Yeast nitrogen base