ß-D-glucan from marine yeast Debaryomyces hansenii BCS004 enhanced intestinal health and glucan-expressed receptor genes in Pacific red snapper Lutjanus peru.

Previous studies have shown that marine yeast Debaryomyces hansenii BCS004 (also known as Dh004) has a potential biotechnological application. The aim of this study was to investigate the structural characterization, antioxidant properties and possible health inductor of dietary ß-D-glucan BCS004. In this study, a glucan BCS004 was obtained containing (1-6)-branched (1-3)-ß-D-glucan with low molecular weight and a high purity of 90 and 91.7% for one and 4 h, respectively. ß-D-glucan BCS004 showed higher antioxidant activity, including DPPH radical and superoxide anion scavenging, ß-carotene bleaching inhibition, and iron chelation activity. An in vitro study showed that ß-D-glucan BCS004 was safe for peripheral blood leukocytes inducing proliferative effects. Moreover, in an in vivo study using ß-D-glucan BCS004 no histopathological damages or intestinal inflammation were observed in fish. The gene expression analysis highlighted that dietary ß-D-glucan BCS004 could also up-regulate glucan and macrophage receptor genes in intestine, such as C-type lectin (CTL) and macrophage mannose receptors (MMR). Overall, the results demonstrated that ß-D-glucan from D. hansenii BCS004 could be an immunostimulant with antioxidant properties and beneficial effects on intestinal health in fish.

Nanosystems as modulators of intestinal dapsone and clofazimine delivery.

The aim of this work was to assess the feasibility of drug nanosystems combination for oral therapy of multibacillary leprosy. The anti-leprotic drugs dapsone (DAP) and clofazimine (CLZ) were incorporated within polymeric nanosystems and studied per se and in combination. DAP was loaded in Eudragit L100 nanoparticles (NPs-DAP) while CLZ was loaded in (poly(lactic-co-glycolic acid) (NPs-CLZ). The nanosystems exhibited around 200 nm in size and a drug loading of 12% for each drug. In vitro cytotoxicity on intestinal Caco-2 cells revealed that after 8 h incubation, DAP alone and within NPs were not toxic up to 100 µg mL-1, while CLZ per se was toxic, reducing cell viability to 30% at 50 µg mL-1. Caco-2 exposed to the combination of NPs-DAP (100 µg mL-1) and NPs-CLZ (50 µg mL-1) exhibited 80% of viability. Caco-2 monolayer permeability assays revealed that DAP and CLZ in the nanosystems per se or in NPs-DAP/ NPs-CLZ combination crossed the intestinal barrier. No significant differences were observed between the single nanosystems or in combination with the apparent permeability values and the amount of permeated drug. Thus, the NPs-DAP/NPs-CLZ combination seems to be a promising platform to deliver both drugs in association, representing an important step towards the improvement of multibacillary leprosy therapy.

Genome and transcriptome scale portrait of sigma factors in Mycobacterium avium subsp. paratuberculosis.

Mycobacterium avium subsp. paratuberculosis (MAP) is the etiological agent of Johne's disease (JD), a chronic gastroenteritis of ruminants and other animals, including primates. Many evidences suggested association of MAP to Crohn's disease, a chronic granulomatous gastrointestinal disease of humans with strong similarities with JD. The present study attempts to evaluate global gene regulation in MAP, which has not been addressed previously, despite the availability of MAP genome sequence. For this purpose, we investigated: (i) the presence of sigma factors and their relationship to sigma factors of other mycobacteria (M. avium subsp.avium, M. tuberculosis, M. bovis, M. leprae and M. smegmatis), and (ii) their expression during different growth conditions and in vitro infection of intestinal epithelial Caco2 cells. MAP genome contains 19 putative sigma factor, but only 12 belong to gene families common to other mycobacteria. Gene expression was evaluated with Real-Time PCR during growth in 7H9 medium and mycobactin J, in 7H9 medium plus mycobactin J and lisozyme, and during infection of Caco2 cells: very different expression patterns were observed and, on the whole, only 7 sigma factors were found to be expressed. sigJ was upregulated during the infection of Caco2 cells. Even if only few sigma factors were expressed in the three conditions tested, the overall high numbers of MAP sigma factors suggests a noteworthy flexibility of this pathogen. Thus, this first report on expression of MAP sigma factors opens the way to an extensive characterization of global gene regulation, as a key to understand strategies of survival and mechanisms of infections used by this organism.