Cytotoxic Activity of Fungal Strains Isolated from the Ascidian Eudistoma vannamei

The cytotoxic activity at 50 μg/ml of extracts obtained from eleven fungal strains associated to Eudistoma vannamei, an endemic ascidian from Northeast Brazil, against two cell lines, i.e., the HCT‐8 (colon cancer) and the MDA‐MB‐435 (melanoma) cell lines, was investigated. The most promising extract (EV10) was obtained from a fungus identified as Aspergillus sp. by molecular analysis and was selected for bioassay‐guided isolation of its active principals. Large‐scale fermentation of EV10 in potato‐dextrose broth followed by chromatographic purification of the active extract from the liquid medium allowed the isolation of the isocoumarins mellein, cis‐4‐hydroxymellein, and trans‐4‐hydroxymellein, besides penicillic acid. All isolated compounds were tested for their cytotoxicity against the tumor cell lines MDA‐MB‐435 and HCT‐8 and revealed penicillic acid as the only cytotoxic compound (cell growth inhibitions >95%).     

Isolation and Screening of Alkaline Lipase-producing Fungi from Brazilian Savanna Soil

Summary Fifty-nine lipase-producing fungal strains were isolated from Brazilian savanna soil by employing enrichment culture tecniques. An agar plate medium containing bile salts and olive oil emulsion was employed for isolating and growing fungi in primary screening assay. Twenty-one strains were selected by the ratio of the lipolytic halo radius and the colonies radius. Eleven strains were considered good producers under conditions of submerged liquid fermentation (shaken cultures) and solid-state fermentation. The most productive strain, identified as Colletotrichum gloesporioides, produced 27,700 U/l of lipase under optimized conditions and the crude lipase preparation was capable of hydrolysing a broad range of substrates including lard, natural oils and tributyrin.     

PPARalpha and PPARgamma regulation of liver and adipose proteins in obese and dyslipidemic rodents

Zucker fatty rats and ob/ob mice are both frequently used hyperlipidemic and insulin-resistant spontaneous genetic models of obesity. We used them to study the effect of PPAR agonists on the protein-expression level in liver and white adipose tissue. PPARalpha-agonist treatments of the rats resulted in that 27% of the quantified hepatic proteins were altered; implicating pronounced peroxisome proliferation and increase in capacity for beta-oxidation of fatty acids although no correction of plasma triglycerides were obtained. On treatment with PPARgamma agonists, adipose proteins were regulated to a much larger extent in the rats compared to mice, 18% and 2%, respectively.     

Recovery of the germfree status of rats and mice monocontaminated with Aspergillus species

The decontamination of monocontaminated rats and mice is reported in this paper. The monocontaminant micro-organism was an Aspergillus species, and the decontamination was applied with success using nystatin and phenol solutions for animals and materials respectively.     

Comparative studies of the action of long duration alcohol drinking on rat pancreatic exocrine cells

The influence of a long term ingestion of ethanol on the rat exocrine pancreas has been studied by electron microscopy. The comparison of micrographs from alcoholic and non alcoholic pancreas allowed us to compare the different organelles of acinar pancreatic cells. These data have been submitted to factorial analysis of correspondences. The ultrastructural modifications revealed out by this analysis are in good agreement with the hypothesis of an adaptation of exocrine cells to a chronic hyperfunctional state.     

Aspect ultrastructural de la lipogénèse dans le tissu adipeux brun

Summary In interscapular brown fat of the rat, appropriately processed so as to maintain membrane structures intact, lipid droplets are in fact liposomes, i.e., lipid filled vacuoles surrounded by a membrane that is related to the smooth endoplasmic reticulum. Thus the endoplasmic reticulum appears as an important component of brown fat cells. — After complete lipid depletion has been achieved by 7 days of fasting, feeding with glucose results in sudden and very conspicuous increase of smooth endoplasmic reticulum; dilatations of the perinuclear cistern and pinocytotic activity at the periphery of the cell contribute to this increase. Simultaneously the cytoplasmic matrix is heavily loaded with glycogen in particulate form. Lipogenesis, as far as can be appreciated by different degrees in electron density, takes place inside the vesicles of the endoplasmic reticulum; increase of such small lipid vacuoles then leads to reconstitution of liposomes; return to the normal aspect is completed 12 hours after the beginning of feeding. — During the phase of glycogen overloading and resulting lipogenesis, glycogen particles may be found in intercellular and pericapillary spaces; the significance of this finding is discussed. — The fundamental difference between both types of fat cells seems to be concerned with the site of lipogenesis: this takes place in the cytoplasmic matrix of white fat cells, so that lipid droplets aggregate without any limiting membrane, whereas in brown fat cells lipogenesis occurs inside cavities of the endoplasmic reticulum and lipids remain permanently enclosed in membranes. This process appears similar to what may be observed occasionally in liver and normally in adrenal cortex, and this might presumably lead to a physico-chemical understanding of the particular aspect of lipogenesis in brown fat, as compared to that in common white fat.

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Travail dédié au Professeur W. Bargmann, en témoignage d'admiration, à l'occasion de son 60e anniversaire.