Biological effect of astaxanthin on alcohol-induced gut damage in Carassius auratus used as experimental model.

Alcohol and its metabolites are responsible for damage both within the gastrointestinal tract and other organs. Alcohol abuse promote intestinal inflammation, that may be the cause of multiple organ dysfunctions and chronic disorders. In this research, the effect of astaxanthin, a powerful antioxidant with several biological effects, on alcohol damage-induced in the intestine of Carassius auratus, was investigated. In the fishes exposed to ethanol, an increase of the intestinal epithelium mucous cells and circulating macrophages, with intestinal mucosa disorganization was observed. In contrast, in the fishes treated with astaxanthin intestinal morphology was restored. By immunohistochemical analysis, using α-Smooth Muscle Actin (α-SMA) and Vasoactive intestinal polypeptide (VIP) antibodies, a reduction of inflammatory states alcohol-induced was evident, with more regular muscularis submucosa and more organized intestinal mucosa without inflammatory cells. The results suggest that astaxanthin treatments can be a good candidate for preventing damage within the gastrointestinal associated with excessive alcohol consumption.

Antibacterial activity of Cladanthus arabicus and Bubonium imbricatum essential oils alone and in combination with conventional antibiotics against Enterobacteriaceae isolates.

Multidrug-resistant bacteria have become common all over the world, necessitating the development of new therapeutic strategies. Synergistic interactions between conventional antibiotics and natural bioactive may have therapeutic benefits in a clinical setting. There are plenty of medicinal plants that have proven efficacy against broad spectrum of micro-organisms. The aim of the work was to assess the antibacterial activity of Cladanthus arabicus, a Moroccan medicinal plant, and Bubonium imbricatum, a Moroccan endemic plant. The evaluation of the synergistic effect of extracted essential oils (EOs) together with some conventional antibiotics was also investigated. Checkerboard test was used to evaluate the interaction of EOs in combination with amoxicillin and neomycin. The results showed that EOs contain a potent activity against the tested Enterobacteriaceae isolates, with inhibition zones values in the range of 8·05 ± 0·1 and 13·1 ± 0·11 mm and MIC values between 200 µg ml-1 to 800 µg ml-1 for C. arabicus and from 400 µg ml-1 to 1600 µg ml-1 for B. imbricatum, respectively. Moreover, the current study allowed concluding that both EOs showed not only satisfactory antibacterial properties but also active effects combined with conventional antibiotics demonstrated by the Fractional Inhibitory Concentration Index (FICI). These findings are very interesting since there are no previous studies on synergistic interactions of these two plants with antibiotics. SIGNIFICANCE AND IMPACT OF THE STUDY: The development of antibiotic resistance is multifactorial, including the specific nature of the relationship of bacteria to antibiotics. This situation has forced scientists to search for new antimicrobial substances from various sources as novel antimicrobial chemotherapeutic agents. Recently, medicinal plants and their derivatives (essential oils, extracts) have become very important in therapeutics because they encounter minimal challenges of the emergence of resistance. In this direction, the antimicrobial activity of the endemic Bubonium imbricatum plant and medicinal Cladanthus arabicus plant essential oils against multidrug-resistant Enterobacteriaceae strains was demonstrated.

Application of Lactobacillus johnsonii expressing phage endolysin for control of Clostridium perfringens.

Clostridium perfringens is frequently found in food and the environment and produces potent toxins that have a negative impact on both human and animal health and particularly on the poultry industry. Lactobacillus johnsonii FI9785, isolated from the chicken gastrointestinal tract, has been demonstrated to exclude Cl. perfringens in poultry. We have investigated the interaction of wild-type Lact. johnsonii FI9785 or an engineered strain expressing a cell wall-hydrolysing endolysin with Cl. perfringens in vitro, using a batch culture designed to simulate human gastrointestinal tract conditions. Co-culture experiments indicated that acid production by Lact. johnsonii is important in pathogen control. The co-culture of the endolysin-secreting Lact. johnsonii with Cl. perfringens showed that the engineered strain had the potential to control the pathogen, but the ability to reduce Cl. perfringens numbers was not consistent. Results obtained indicate that survival of high numbers of Lact. johnsonii will be essential for effective pathogen control. Significance and impact of the study: The bacterium Lactobacillus johnsonii FI9785 reduces numbers of the pathogen Clostridium perfringens in vitro. Biocontrol was improved by engineering the strain to produce and export a cell wall-hydrolysing endolysin, but good survival of the producer strain is essential. The production of bacteriophage endolysins by commensal bacteria has the potential to improve competitive exclusion of pathogens in the gastrointestinal tract.

Does the light influence astaxanthin production in Xanthophyllomyces dendrorhous?

Astaxanthin (C40H52O4) is an important natural pigment that has considerable promising applications in human health. Until now, many efforts were made aimed to develop economically sustainable bioprocesses alternative to the chemical synthesis, to satisfy the increasing demand of this ketocarotenoid from feed, food and cosmetic industries. The extraction of natural astaxanthin from the yeast Xanthophyllomyces dendrorhous till now seems to be rather expensive if compared with chemically synthesized astaxanthin. In this article, astaxanthin production by Xanthophyllomyces dendrorhous under two different conditions was studied: a first effort was made using a conventional reactor while a second using an enlightened one. This research was aimed also to optimise astaxanthin production by testing the influence of the light and of some nutrient sources. From fermentation tests, an astaxanthin yield ranging about 970 µg g(-1) was obtained after fed batch cultivation in the conventional reactor. In the enlightened reactor lower values, about 930 µg g(-1), were found.