Marine Lactobacillus pentosus H16 protects Artemia franciscana from Vibrio alginolyticus pathogenic effects.

Vibrio alginolyticus is an opportunistic pathogen which may affect different aquatic organisms. The aim of this study was to assess the probiotic properties and the protective mode of action of Lactobacillus pentosus H16 against V. alginolyticus 03/8525, through in vitro and in vivo studies using Artemia franciscana (hereafter Artemia). This strain showed antimicrobial activity against V. alginolyticus 03/8525 and Aeromonas salmonicida subsp. salmonicida ATCC33658 possibly related to lactobacilli organic acid production. It was able to survive at high rainbow trout bile concentrations and showed high selective adhesion to rainbow trout mucus (1.2×10(5)±8.0×10(3) cells cm(-2)). H16 outcompeted V. alginolyticus 03/8525 and A. salmonicida subsp. salmonicida ATCC33658, greatly reducing their adherence to rainbow trout mucus (64.8 and 74.1%, respectively). Moreover, H16 produced a cell-bound biosurfactant which caused an important decrease in the surface tension. H16 also protected Artemia nauplii against mortality when it was administered previous to V. alginolyticus 03/8525 inoculation. Furthermore, H16 bioencapsulated in Artemia, suggesting that it is possible to use live carriers in its administration. We conclude that the ability of L. pentosus H16 to selectively adhere to mucosal surfaces and produce cell-bound biosurfactants, displacing pathogenic strains, in addition to its antimicrobial activity, confer H16 competitive advantages against pathogens as demonstrated in in vivo challenge experiments. Thus, L. pentosus H16, a marine bacterium from the intestinal tract of hake, is an interesting probiotic for Artemia culture and also has the potential to prevent vibriosis in other aquaculture activities such as larvae culture and fish farming.

Acetaldehyde increases the activity and gene expression of urokinase type plasminogen activator in a hepatic stellate cell line.

The aim of this study was to investigate the effect of acetaldehyde on the activity and expression of urokinase type plasminogen activator gene in a clone of hepatic stellate cells. CFSC-2G cells showed typical morphological changes of the stellate cell activation, which were accompanied by an increase in the amount of collagen with all doses of acetaldehyde used. The treatment of the cells with doses of 100 and 175 micromol/l acetaldehyde, produced an increase in the urokinase type plasminogen activator activity not only in the cell extract, but also in conditioned medium. However, the use of higher doses of acetaldehyde (250 and 350 micromol/l) produced an inhibitory effect on the urokinase type plasminogen activator activity. In contrast, the higher urokinase type plasminogen activator gene expression was observed with doses of 175, 250, and 350 micromol/l. Our results shown that acetaldehyde induced changes in synthesis, release, and expression of urokinase type plasminogen activator in CFSC-2G cells. Those findings suggest that the alterations in the synthesis and expression of the urokinase type plasminogen activator might be another event associated to the activation of hepatic stellate cell after exposure to hepatotoxic agents like-acetaldehyde. The role of urokinase type plasminogen activator in fibrogenesis was analyzed.