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Biomedical subjects

J Fabregas

Publications and source records attributed to J Fabregas.

8 recordsLinked to original sources

In vitro inhibition of the replication of haemorrhagic septicaemia virus (VHSV) and African swine fever virus (ASFV) by extracts from marine microalgae.

We have screened for in vitro inhibition of viral replication with extracts from the following marine microalgae: Porphyridium cruentum, Phaeodactylum tricornutum, Tetraselmis suecica, Chlorella autotrophica, Dunaliella tertiolecta, Dunaliella bardawil, Isochrysis galbana, Isochrysis galbana var Tiso, Ellipsoidon sp. and Tetraselmis tetrathele. We have used as viral models two enveloped viruses of significant economic importance, the viral hemorrhagic septicemia virus (VHSV) of salmonid fish and the African swine fever virus (ASFV). The aqueous extracts from P. cruentum, C. autotrophica and Ellipsoidon sp., produced a significant inhibition of the in vitro replication of both viruses in a dose-dependent manner. That this inhibition could be due to sulfated polysaccharides was suggested because the same pattern of viral inhibition was obtained by using exocellular extracts from microalgae enriched in these compounds and/or dextran sulfate of high molecular weight. However, the inhibition of viral replication did not correlate with the percentage of sulfatation of the exocellular polysaccharides. Extracts from marine microalgae may have prophylactic utility against fish and mammalian viral diseases.

African Swine Fever Virus↗

Interaction of lectins with Cryptosporidium parvum.

Cell surface carbohydrates from four clinical isolates of Cryptosporidium parvum were analyzed by agglutination assays using a battery of 20 highly purified lectins with affinity for receptor molecules containing N-acetyl-D-glucosamine (GlcNAc), N-acetyl-D-galactosamine, galactose, mannose, glucose, fucose, and N-acetyl-neuraminic acid. Tomentine, a lectin from the green seaweed Codium tomentosum, and UEA-II lectin, from Ulex europeus, both of them GlcNAc-specific lectins, agglutinated the oocysts. Subsequent inhibition assay confirmed the presence of this sugar on the surface of Cryptosporidium parvum oocysts. Codium fragile lectin, from another green seaweed, also exhibited agglutination activity against the oocysts. This is the first published demonstration of such an interaction between a human coccidian and lectins from seaweeds.

Animals↗

Effect of oil and dispersant on growth and chlorophyll a content of the marine microalga Tetraselmis suecica.

Low hydrocarbon concentrations stimulated the growth of Tetraselmis suecica, whereas higher concentrations (200 ppm) inhibited growth. The content of chlorophyll a in this microalga was affected in a similar way. Crude oil had the most marked effects. Dispersant SEAKLIN-101-NT and mixtures of oil and SEAKLIN-101-NT did not show selective toxicity for the microalga, although inhibitory effects could be observed at high concentrations.

Chlorophyll↗

Tetrafungin, a new polyene macrolide antibiotic. I. Fermentation, isolation, characterization, and biological properties.

A new polyene macrolide antifungal antibiotic, named tetrafungin, was isolated from the cultured mycelium of a Streptomyces strain. Fermentation, isolation, physico-chemical and biological properties of the antibiotic are described. Its UV absorption spectrum and its physico-chemical characteristics place this antibiotic in the group 2.2.2.3 of the Berdy classification.

Anti-Bacterial Agents↗

Tetrafungin, a new polyene macrolide antibiotic. II. Taxonomy of the producing organism and comparison with nystatin by means of high performance liquid chromatography.

Tetrafungin, a new polyene macrolide antibiotic, is produced by a Streptomyces strain identified as a new subspecies of Streptomyces albulus and named Streptomyces albulus subsp. tetrafungini. Tetrafungin and nystatin have been investigated and compared by HPLC. It has been demonstrated that tetrafungin and nystatin differ qualitatively in, at least, one component, and quantitatively in their relative amounts of common components.

Anti-Bacterial Agents↗

Differentiation of Candida guilliermondii varieties by lectin-like substances from marine algae.

Lectin-like substances of 54 marine algae, corresponding to 30 red algae and 24 brown algae, were studied to estimate the agglutination activity against Candida guilliermondii. Extracts of Dictyopteris membranacea, Bifurcaria bifurcata, Halidrys siliquosa, Ascophyllum nodosum, Fucus serratus and F. spiralis algae showed selective agglutinating activities for C. guilliermondii "sensu stricto" and some of its varieties. According to their response to agglutination (positive or negative), certain algal extracts enabled the differentiation of varieties of C. guilliermondii independently of the titre values. Three extracts of brown algae were sufficient to identify 4 varieties of C. guilliermondii. The results suggest that lectin-like substances from marine algae may be valuable reagents as assistant tools for the identification of yeast strains.

Agglutination↗