Efficacy of lactic acid bacteria supplementation against Fusarium graminearum growth in vitro and inhibition of Zearalenone causing inflammation and oxidative stress in vivo.

Fusarium graminearum invasion and Zearalenone (ZEN)-mycotoxin contamination are considered the most global threat to food and feed. This study investigates the effect Lactobacillus plantarum MON03 viable cells (LPVC) and LP free cells supernatant (LPFCS) against Fusarium graminearum growth and ZEN production in vitro and evaluates if treatment with LP viable cells can counteract the negative effect of ZEN on inflammation and oxidative stress in mesenteric lymph nodes and serum biochemical parameters in mice. For the in vitro study, 7 days of LPVC, LPFCS and F. graminearum co-incubation at different concentrations was done in order to determine the antifungal activity and ZEN- production inhibition. Regarding the in vivo study, Balb/c mice were treated as following: Control, ZEN group, LP group and ZEN + LP group for 30 days. In vitro, LPVC showed an excellent antifungal activity after 7 days of co-incubation (103 CFU/ml). LPVC was succeeded also to inhibit ZEN production by the fungi. In vivo, ZEN has shown an important oxidative damage. As a result of the exposure to ZEN, an increase cytokines, as effectors of an inflammatory response, were observed in the mesenteric lymph nodes (MLN) of intoxicated mice. In parallel, a serum biochemical change was also observed. LPVC induced a reduction of ZEN-induced oxidative stress and counteracts also the biochemical parameters damage and the inflammatory markers increased by ZEN. LPVC can be valorized as an anti-cating agent in the vitro and in the gastro-intestinal tract to decrease ZEN-toxic effects.

Immunological effects of AFM1 in experimental subchronic dosing in mice prevented by lactic acid bacteria.

AIM: Recently, higher contamination by aflatoxin M1 (AFM1) has been detected in many countries. Unfortunately, many tons of contaminated milk and milk byproducts are removed from the food chain to avoid human contamination; as a consequence of higher economic losses. Fewest number of studies are interested to AFM1 detoxification using lactic acid bacteria. MATERIALS AND METHODS: In this study, AFM1-degradation using Lactobacillus paracasei BEJ01 (LPBEJ01) was tested in vitro. The preventive effect of LPBEJ01 against AFM1 immunobiological effects in mice are treated orally during 3 weeks with 100 µg AFM1, LPBEJ01 (2 × 109 CFU/ml∼2 mg/kg p.c.) and a mixture of AFM1 and LPBEJ01. RESULTS: In vitro LPBEJ01 was found able to absorb 98% of AFM1 (100 µg/ml) in liquid medium after 24 h and more than 95% of AFM1 could be eliminated after 24 h in a solid-state fermentation. Animals treated with AFM1 obtained lower body weight than the control ones. The mitogenic response of spleen mononuclear cells (SMCs) in vivo was higher in mice treated with AFM1. The SMC of mice treated with AFM1 produced lower levels of IL-2, higher levels IL-4 and no effect on IL-10 production. The peritoneal macrophages of mice that treated with AFM1 released less H2O2, while mice exposed orally with the mixture of AFM1 and LPBEJ01 produced higher levels. CONCLUSION: LPBEJ01 was safe and it did not have any sign of toxicity. It can be used as an additive for AFM1-detoxification contamination in the food chain in countries suffering from this problem.

Lactobacillus paracasei alleviates genotoxicity, oxidative stress status and histopathological damage induced by Fumonisin B1 in BALB/c mice.

Fumonisin B1 (FB1) is a prevelant mycotoxin in our alimentary chain. It was produced by the fungi of the genus Fusarium verticillioides and Fusarium proliferatum. FB1 was playing as a competitive inhibitor of ceramide synthase; a key enzyme in the biosynthesis of sphingolipids. Indeed, it was associated with several affects in humans and livestock animals. The aim of our report was elucidated to evaluate the protective effects of Lactobacillus paracasei BEJ01 (LP) isolated from the traditional butter of Tunisia against the FB1 genotoxicity, hematoxicity, oxidative stress and histological damage in liver and kidney of BALB/c mice. Forty old week mice were randomly divided into four treatment groups (10 mice/group): Group 1: control; Group 2: LP (2 × 109 CFU/ml ~ 2 mg/kg p.c); Group 3: FB1 (100 µg/kg p.c.); Group 4: LP (2 × 109 CFU/ml ~ 2 mg/kg p.c) + FB1 (100 µg/kg p.c.). 48 h after the end of the treatment (10 days), the mice were sacrificed and the blood, liver and kidney were collected. The blood was used for hematological and biochemical studies. Liver and kidney samples were the target for evaluation of oxidative stress enzymes status and histopathological damage. The results indicated that FB1 was induced toxicities in the blood parameters and in liver and kidney tissues as well as in the profile of oxidative stress enzymes levels. The co-treatment with LP was found able to mitigate the FB1 toxicities by reduction of its bioavailability in the gastro intestinal tract. However, treatment with LP alone was safe and no sign of toxicity was showed. In Summary, the LP strain was able to prevent FB1 toxicities and indeed it could be exploited as one of the biological strategies for foodstuffs decontamination.

Strain tuned topology in the Haldane and the modified Haldane models.

We study the interplay between a uniaxial strain and the topology of the Haldane and the modified Haldane models which, respectively, exhibit chiral and antichiral edge modes. The latter were, recently, predicted by Colomés and Franz (2018 Phys. Rev. Lett. 120 086603) and expected to take place in the transition metal dichalcogenides. Using the continuum approximation and a tight-binding approach, we investigate the effect of the strain on the topological phases and the corresponding edge modes. We show that the strain could induce transitions between topological phases with opposite Chern numbers or tune a topological phase into a trivial one. As a consequence, the dispersions of the chiral and antichiral edge modes are found to be strain dependent. The strain may reverse the direction of propagation of these modes and eventually destroy them. This effect may be used for strain-tunable edge currents in topological insulators and two-dimensional transition metal dichalcogenides.