Factors controlling the expansion behavior of favia favus (Cnidaria: Scleractinia): effects of light, flow, and planktonic prey.

Colonies of the massive stony coral Faviafavus were exposed to different flow speeds and levels of light, and to the addition of zooplankton prey. The relative importance of each factor in controlling polyp expansion behavior was tested. The coral polyps fully expanded when they were exposed to low light intensity (0-40 micromol m(-2) s(-1)) and high flow speed (15 cm s(-1)), regardless of prey presence. They also partially expanded under low and medium light (40-80 micromol m(-2) s(-1)) at medium flow speed (10 cm s(-1)). The corals expanded their polyps only when they were exposed to light levels below compensation irradiance (Icom: light level at which photosynthesis = respiration), which was determined to be about 107 +/- 24 micromol m(-2) s. The results presented here indicate that high flow, low light, and the presence of planktonic prey induce coral expansion. There is a hierarchy of response to these stimuli, in which light level and flow speed are dominant over prey presence. Coral response to these three factors is probably due to the relative importance of gas exchange and zooplankton prey.

[Emergencies in pedodontics]. / Urgencias en odontopediatría.

This paper describes several emergencies in pediatric dentistry, its prevention, diagnosis and treatment.

Urgencias en odontopediatría. / [Emergencies in pedodontics]

This paper describes several emergencies in pediatric dentistry, its prevention, diagnosis and treatment.

Pseudomonas lectin PA-I detects hybrid product of blood group AB genes in saliva.

Pseudomonas aeruginosa galactophilic lectin PA-I exhibits an outstanding affinity for soluble hybrid oligosaccharide products of human A and B genes in saliva of heterozygous AB individuals. Neither A nor B salivas, nor an artificial mixture of them, inhibit PA-I hemagglutinating activity to the same extent as saliva from heterozygotes. Other lectins examined do not exhibit this property.

Purification and characterization of the gonad lectin of Aplysia depilans.

Extracts of gonads and fertilized eggs of Aplysia depilans contain a D-galacturonic and D-galactose-binding lectin. This lectin reacts strongly with rabbit and human erythrocytes independent of ABO blood groups, weakly with dog, mouse, rat, and chick erythrocytes and not at all or very weakly with sheep erythrocytes. Purification of the gonad lectin was easily achieved, with a high yield, by heating to 70 degrees C, precipitation with ammonium sulfate and affinity chromatography on Sepharose 4B. The purified lectin was found to be a glucoprotein of molecular mass around 55-60 kDa; it stimulates mitogenesis of human peripheral lymphocytes.

Ovarian substance induces steroid production in cultured granulosa cells.

The rat ovary produces an apparently low molecular weight substance that mimics the action of follitropin (FSH) on ovarian granulosa cells in culture. Similar to FSH action, the ovarian substance (OS) induces temporal cell rounding and, later on, intensive progestin production. However, unlike FSH, OS does not induce accumulation of cyclic AMP (cAMP) in the granulosa cells. The ovarian factor cannot be cAMP as its action is not abolished by phosphodiesterase (PDE) treatment. Neither is it a possible PDE inhibitor, as it does not augment cAMP accumulation in granulosa cells or Friend erythroleukemic cells induced by FSH or PGE1, respectively. The factor is still active after heating for 20 min at 90 degrees C but is rapidly inactivated by alkali treatment. In addition, treatment with various proteases did not abolish the steriodogenic activity. These findings suggest a possible novel intraovarian regulator of the granulosa cell function.

A new mitogenic D-galactosephilic lectin isolated from seeds of the coral-tree Erythrina corallodendron. Comparison with Glycine max (soybean) and Pseudomonas aeruginosa lectins.

The lectin of Erythrina corallodendron (Caesalpiniaceae) seeds was purified by heating, ammonium sulfate fractionation, and affinity chromatography on acid-treated Sepharose. The purified lectin is similar to the soybean lectin in being a glycoprotein of molecular weight around 110 000 - 120 000 and having D-galactosephilic activity. This lectin, like the soybean and Pseudomonas aeruginosa lectins, binds to D-galactosamine, N-acetyl-D-galactosamine, alpha- and beta-galactosides as well as to D-galactose. Like these lectins it absorbs onto either untreated or enzyme (papain or neuraminidase) treated human red blood cells, but exhibits a considerable mitogenic activity towards human lymphocytes (predominantly T cells) only after their treatment with neuraminidase. This mitogenic stimulation of lymphocytes is inhibited by D-galactose and its derivatives. Despite the great similarity between them, the E. corallodendron, soybean, and Pseudomonas lectins differ in regard to the intensity of their agglutinating activity towards erythrocytes obtained from different animals and human donors of diverse ABO blood groups. This phenomenon may be attributed to the difference in the affinities of the three lectins to the various D-galactose derivatives and to their molecular properties.

Estimation of nonspecific lectin-mediated staining of glutaraldehyde-fixed cells.

Lectin-mediated stainings are widely used for the visualization of carbohydrate-carrying cellular components using the electron microscope. The use of glutaraldehyde-fixed cells for these stainings introduces the possibility of low nonspecific lectin-trapping by the glutaraldehyde which coats the cells. This trapping was estimated by means of peroxidase-binding to human leukocytes. Tetrahymena pyriformis and Escherichia coli cells and was shown to be prevented by rinsing the glutaraldehyde-fixed cells in an amino solution before exposure to the lectin.

Interaction of the mannosephilic lectins of Pseudomonas aeruginosa with luminous species of marine enterobacteria.

The marine bacteria Beneckea harveyi and Photobacterium leiognathi were shown to bear mannose-containing binding sites for the mannosephilic lectins of Pseudomonas aeruginosa and concanavalin A (Con A). The interaction between the lectins and the marine bacteria was demonstrated by the bacteriagglutination test, by adsorption of the lectins onto the bacteria and by mannose-specific peroxidase-binding to the lectin-coated bacteria. Treatment of the bacteria with formaldehyde, phenol, ethanol or boiling them for 15 min, did not alter their ability to adsorb the lectins. The growth rate of the marine bacteria was unaffected when either the Pseudomonas lectins or Con A was added to the culture medium.

Differences in antibacterial activity of benzalkonium chloride.

Benzalkonium solutions obtained from different manufacturers were shown to have different activities. This difference in activity was related to the composition of the benzalkonium chloride. The potential seriousness of this situation is emphasized, and a recommendation is made that the official monographs on benzalkonium chloride be amended appropriately, noting the apparently superior antibacterial activity of the tetradecyl (C14) homolog.

Mannose-binding hemagglutinins in extracts of Pseudomonas aeruginosa.

Mannose-binding hemagglutinins were found in the extracts of a pyocyanin-forming Pseudomonas aeruginosa, which contain galactose-specific hemagglutinins. They were purified simultaneously with the latter proteins by heating to 70 degrees C, precipitating with ammonium sulfate, application to a Sepharose 4B column, and elution from it by 0.05 M mannose. The mannose-specific hemagglutinins were shown to be similar to the galactophilic ones in (a) being glycoproteins of very low molecular weight (about 11 000 by SDS gel electrophoresis), (b) their tendency to aggregate, and (c) their ability to effect stronger agglutination of erythrocytes treated with papain than of untreated ones. They were found to resemble them also in their reaction with simple sugars and interactions with divalent cations, which are essential for their activity. In these properties, as well as in their relative resistance to heat and to proteolytic enzymes, these two types of bacterial hemagglutinins are like most of the plant, contrasted with the animal, hemagglutinins. The reactions with mannose and mannose-bearing compounds (yeast mannan, horseradish peroxidase (EC 1.11.1.7), and serum globulins), which are not shared with the galactophilic Pseudomonas hemagglutinins, indicate a relationship of the mannose-binding protein of Pseudomonas to the plant lectin concanavalin A. The mannose-binding hemagglutinins do not exhibit identical cell-agglutinating spectra owing to difference in profiles of sugar specificity and relative affinity to mannose derivatives compared with free mannose.

Specific agglutination of Escherichia coli O128B12 by the mannose-binding proteins of Pseudomonas aeruginosa.

The mannosephilic haemagglutinins of Pseudomonas aeruginosa were found to agglutinate cells of Escherichia coli O128B12, to be adsorbed onto them and to attach peroxidase to them. These reactions were specifically inhibited by D-mannose. No agglutination by this Pseudomonas haemagglutinin was obtained when several other enteropathogenic types of Escherichia coli and some other Gram-negative bacteria were examined. Concanavalin A, which also reacted with Escherichia coli O128B12 cells, interacted with some of the other bacteria examined, too. Escherichia coli O128B12 was not agglutinated by the Pseudomonas galactosephilic haemagglutinins and those of the plant Phaseolus vulgaris. Its maximal agglutination by the Pseudomonas mannosephilic haemagglutinins was obtained employing cells grown for 4-6 h in conventional media. The growth temperature, aeration and presence of certain amino acids, but not D-mannose, in the culture medium had some effect on the agglutination in tensity; pH 6-8 was optimal for it and only at pH 3.0-3.2 no agglutination was observed. Treatment of the bacteria by proteolytic enzymes, ethanol or formaldehyde did not alter their agglutinability by either the Pseudomonas lectin or by antibodies produced against them in rabbits. Heating of the bacteria to 100 degrees C prevented their agglutination by the Pseudomonas lectin and lowered their ability to adsorb it, but did not significantly affect their reactions with the rabbit antibodies.