Lectinas, agentes antihemostáticos y compuestos positivos al reactivo de Dragendorff en algas marinas de Venezuela y Túnez / Lectins, antihaemostatic agents and dragendorff positive compounds in marine algae from Venezuela and Tunibia

Las algas marinas recolectadas en Túnez y Venezuela han sido analizadas buscando la presencia de lectinas, agentes antihemostáticos y compuestos Dragendorff positivo. De 34 especies estudiadas, la actividad de las lectinas fue demostrada en los extractos de 14 de ellas. De éstas, las especies consideradas de más valor para estudios posteriores fueron Halimeda tuna, H.opuntia, Bryotamnion triquetum, B. seaforthii, Codium isthmocladum y Centroceras clavulatum. La actividad anticoagulante fue detectada en extractos de 26 de las especies analizadas. El extracto con más actividad de potencia inhibidora fue el de Centroceras clavulatum, pero el de Codium isthmocladum también se consideró interesante. Once especies fueron estudiadas por su contenido de compuestos Drangendorff positivo. Tanto las betainas como el compuesto de sulfonio terciario del tipo 3-dimetilsulfoniopropinato (DMSP) o una mezcla de DMSP y una betaina fueron aisladas y caracterizadas en todas las especies analizadas

Assimilation of polychlorinated biphenyls by a marine mollusc and comparison with a rat.

The marine mollusc Aplysia californica was fed seaweed Rhodymenia palmata contaminated with polychlorinated biphenyls (PCBs) at a high (experimental) and low (control) level for a period of 18 days in flow-through systems which limited the animals to dietary uptake. The assimilation of PCBs, determined by subtraction of fecal output from food intake, was greater at the high dosage (94 +/- 29%) than at the low dosage (84 +/- 22%). Assimilation selectivity of the different congeners favored those with lower chlorine content, and discriminated against those chlorinated in the para position on one of the rings. After assimilation, selectivity for incorporation into the hepatopancreas favored those congeners with higher chlorine contents over those with but 1 to 3 chlorines on the molecule. Similarities between incorporation into the liver of rats and into the hepatopancreas of Aplysia were found, suggesting that common mechanisms for bioaccumulation, and by extension, physiological effects, may be present in such diverse species of the animal kingdom.

[Determination of Mg and Zn contents of Naruto "wakame" (Undaria pinnatifida)].

The contents of Mg and Zn in the sea-weed "wakame" were determined and compared at different growth stages, in different parts, for different root cultivation intervals, and in processed foods. The results obtained were as follows: 1. Mg (2.09-2.60 g/100 g) and Zn (8.00-10.76 mg/100 g) contents were independent of growth stage with the exception of Zn (29.00-35.78 mg/100 g) in the natural young "wakame". 2. The mineral contents of leaves, stipes, fruiting bodies and rhizoids of "wakame" at different growth stages were determined. The contents of Mg (1.00-2.36 g/100 g) and Zn (3.93-12.01 mg/100 g) were richer in leaves and stipes than in fruiting bodies and rhizoids. 3. Densely cultured "wakame" showed higher contents of Zn (6.73 mg/100 g) than thinly cultured plants (5.99 mg/100 g), and Mg content was not affected by changes in environmental conditions. 4. The Mg/Ca ratios reached a maximum in the stipe (3.3) and at fruiting bodies (2.9) in the middle stage, and in the base of the stipe of the mature plant (3.5). 5. Contents of the minerals in processed foods were determined. "Suboshi" was rich in Mg (1.07 +/- 0.42 g/100 g), and "Haiboshi" was rich in Zn (10.90 +/- 1.20 mg/100 g). The mineral contents in "Enzo" were small.

Detection of extracellular calcium gradients with a calcium-specific vibrating electrode.

We have developed a vibrating calcium-specific electrode to measure minute extracellular calcium gradients and thus infer the patterns of calcium currents that cross the surface of various cells and tissues. Low-resistance calcium electrodes (routinely approximately 500 M omega) are vibrated by means of orthogonally stacked piezoelectrical pushers, driven by a damped square wave at an optimal frequency of 0.5 Hz. Phase-sensitive detection of the electrode signal is performed with either analogue or digital electronics. The resulting data are superimposed on a video image of the preparation that is being measured. Depending on the background calcium concentration, this new device can readily and reliably measure steady extracellular differences of calcium concentration which are as small as 0.01% with spatial and temporal resolutions of a few microns and a few seconds, respectively. The digital version can attain a noise level of less than 1 microV. In exploratory studies, we have used this device to map and measure the patterns of calcium currents that cross the surface of growing fucoid eggs and tobacco pollen, moving amebae and Dictyostelium slugs, recently fertilized ascidian eggs, as well as nurse cells of Sarcophaga follicles. This approach should be easily extendable to other specific ion currents.

Hypoglycemic activity of several seaweed extracts.

The hypoglycemic activity of several seaweed extracts on rabbits was studied. Ethanol extracts of Laminaria ochroleuca, Saccorhiza polyschides and Fucus vesiculosus were administered orally to normal animals and their effects on glycemia and triglyceridemia evaluated. Crude polysaccharides and protein solutions from Himanthalia elongata and Codium tomentosum were also assayed. Polysaccharides and proteins from H. elongata caused a significant reduction in blood glucose 8 h after intravenous administration. A case of 5 mg/kg of crude polysaccharide lowered glycemia about 18% in normal rabbits and by about 50% in alloxan-diabetic animals, while the protein solution lowered glycemia in diabetic rabbits by about 30%.

[Transient thyrotoxicosis induced by Japanese kombu].

Iodine-induced thyrotoxicosis (ITT) has not been reported in Japan. We found that excessive intake of Japanese kombu could elicit ITT. Two Japanese women, 42 and 59 years old, developed thyrotoxicosis one month and one year, respectively, after having eaten foods containing 28-140 mg/day of iodine, calculated from their daily diet. Both patients had high concentrations of serum T3, low ratios of serum T3/T4 or T4/r-T3 compared with untreated Graves' disease, and high concentrations of serum inorganic iodine compared with the mean (M +/- SD: 2.05 +/- 0.99 micrograms/dl) plus 2SD in people eating common foods. Their thyrotoxic signs and symptoms disappeared, and their serum T4, T3, r-T3 and T4/r-T3 normalized one month after the prohibition of kombu intake. To clarify the source of iodine, the iodine content of the kombu and the iodine concentration in water in which the kombu was immersed were measured. Ninety-nine % of the iodine was found in water after 15 min boiling. These findings suggest that a daily intake of more than 28 mg/day of iodine in a diet containing kombu might induce ITT.

Chernobyl fallout measurements in some Mediterranean biotas.

The radioactivity of various terrestrial vegetation leaves characteristic of Mediterranean countries has been measured after the Chernobyl accident. In addition, we paid particular attention to lichens and seaweed which are considered as bioindicators of radioactive contamination. Most measurements were performed non-destructively using both coaxial and planar HPGe detectors. For odd mass radionuclides having low energy lines, such as 125Sb or 141Ce the sensitivity of the planar HPGe detector is better than the coaxial detector. The concentration of long-lived fission nuclides remaining three months after the accident were found to be enhanced in needle form leaves and in lichens. The seaweed Sphaerococcus exhibits a strong specific activity for iodine and ruthenium elements and poor concentration for caesium nuclides. The activity ratios of different isotopes of the same element measured in vegetation samples agree well with values found in airborne aerosols by other authors. The activation nuclide 110mAg is found in all samples with the same ratio 110mAg/137Cs = (1.0 +/- 0.2).10(-2) as in the soil deposition.

Human intake of arsenic and iodine from seaweed-based food supplements and health foods available in the UK.

A number of seaweed-based products were analysed for total and 'reducible' arsenic and total iodine. Maximum potential intakes of the two elements were estimated using the manufacturers' recommended does. The levels of reducible arsenic found were generally low and, with one exception, ingestion of the products is unlikely to lead to the Joint Expert Committee on Food Additives (JECFA) Tolerable Daily Intake being exceeded. Iodine levels varied widely even between different samples of the same product. In a number of these cases the potential iodine intake is very high.

Effect of pretazettine and viva-natural, a dietary seaweed extract, on spontaneous AKR leukemia in comparison with standard drugs.

Antileukemic activity of pretazettine hydrochloride (PTZ: a narcissus alkaloid) and Viva-Natural (a seaweed extract) has been confirmed against spontaneous AKR T cell leukemia in mice containing 20% of advanced leukemia. The activity of both agents has been compared with selected standard cytotoxic drugs, vincristine (VCR), methotrexate (MTX), 6-thioguanine (6-TG), and adriamycin (ADR), and immunomodulators, pyran copolymer (MVE-2), isoprinosine, levamisole and tilorone. PTZ activity seems to be superior (90% increase in life span, ILS) to those of MTX (71% ILS), 6-TG (60%), and ADR (49%), and inferior to VCR (114% ILS). Viva-Natural has been found to be the only immunomodulator (61%) active against AKR T cell leukemia, while all standard immunomodulators tested were not active. Combination treatment of PTZ with VCR, or 6-TG, or ADR, or Viva-Natural were synergistic, but combination of PTZ with MTX was not beneficial. PTZ or VCR has been found to be therapeutically very effective (323 or 347% ILS, respectively) against mice in advanced stage of leukemia, and induced complete clinical remissions. Also, PTZ has been found to reverse the leukemia-enhancing effect of ciclosporin in AKR mice at preleukemic stage.

Effect of dietary seaweed preparations on 1,2-dimethylhydrazine-induced intestinal carcinogenesis in rats.

Nineteen preparations from 8 species of edible seaweeds, sodium alginate and cellulose powder were incorporated into a basic diet in proportions ranging from 0.05% to 2.0%, and used as experimental diets. Experimental rats were fed these diets and controls were fed the basic diet for 12 weeks. All rats also received the carcinogen, 1,2-dimethylhydrazine, during above period. After 20 weeks, all rats were autopsied and the incidence of intestinal tumors induced were examined. There was a significant decrease in incidence in rats fed 6 preparations from Eisenia bicyclis, Laminaria angustata, L. angustata var. longissima and Porphyra tenera (P less than 0.05).

Anticancer activity of a natural product, viva-natural, extracted from Undaria pinnantifida on intraperitoneally implanted Lewis lung carcinoma.

A natural product, named Viva-Natural, extracted from a dietary seaweed Undaria pinnantifida has been found to be therapeutically active against Lewis lung carcinoma (LLC). Viva-Natural also demonstrated moderate prophylactic activity against LLC in allogeneic mice. The active principle(s) which was concentrated in the water-insoluble fraction of Viva-Natural was essentially noncytotoxic in KB cell cultures, and probably a polysaccharide. Viva-Natural was found to be significantly effective in enhancing the natural cytolytic activity of peritoneal macrophages against KB cells as targets in in vitro assay, suggesting that the antitumor action of Viva-Natural might be indirect through the activation of nonspecific immune systems. A combination therapy of Viva-Natural and standard anticancer drugs was additively or synergistically effective.