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Inducciòn de crecimento de L. casei 393 despùs del proceso digestivo in vitro.
No full textgastric stress, Lactobacillus case
β-glucans and probiotics
Get PDFIn the recent decades, several health-promoting features have been ascribed to β-glucans. Biological properties such as anti-cancer, antiinflammatory and immune-modulating activity have been claimed for these polysaccharides. Moreover, when β-glucans were used in association with probiotic bacteria, prebiotic effects have been demonstrated, due to their ability to enhance growth, metabolism and/or beneficial activities of probiotics. This review shall present an overview of those studies, which have documented the diverse health-benefits of β-glucans and their association with probiotics
Chemical composition and the anti-melanogenic potential of different essential oils
No full textTyrosinase is the key enzyme of melanogenesis, the process that determines skin and hair pigmentation in mammals. In humans, various pigmentary disorders depend on excessive melanin production and accumulation. Moreover, tyrosinase activity can cause the undesirable browning of plant-derived food. For such reasons, ongoing researches aim at developing effective melanogenesis inhibitors for medical, cosmetic and food applications. Diverse biological activities have been observed for certain plant essential oils (EOs) and their components. In this study, the EOs from nine different plant species were investigated for their anti-melanogenic potential. The EOs chemical composition was assessed by gas chromatography-mass spectrometry (GC-MS) revealing the presence of some constituents with known tyrosinase inhibitory ability. Most EOs inhibited significantly and dose-dependently mushroom tyrosinase. Two samples also inhibited the activity of tyrosinase from murine B16 melanoma cells. Our findings indicate that some of the analysed EOs may be promising natural sources for developing novel anti-melanogenic agents, thus having a good potential in medical, cosmetic and food-processing industries
The potential of lactic acid bacteria to colonize biotic and abiotic surfaces and the investigation of their interactions and mechanisms
No full textLactic acid bacteria (LAB) are a heterogeneous group of Gram-positive bacteria that comprise several species which have evolved in close association with humans (food and lifestyle). While their use to ferment food dates back to very ancient times, in the last decades, LAB have attracted much attention for their documented beneficial properties and for potential biomedical applications. Some LAB are commensal that colonize, stably or transiently, host mucosal surfaces, inlcuding the gut, where they may contribute to host health. In this review, we present and discuss the main factors enabling LAB adaptation to such lifestyle, including the gene reprogramming accompanying gut colonization, the specific bacterial components involved in adhesion and interaction with host, and how the gut niche has shaped the genome of intestine-adapted species. Moreover, the capacity of LAB to colonize abiotic surfaces by forming structured communities, i.e., biofilms, is briefly discussed, taking into account the main bacterial and environmental factors involved, particularly in relation to food-related environments. The vast spread of LAB surface-associated communities and the ability to control their occurrence hold great potentials for human health and food safety biotechnologies
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Antimicrobial activity of Lactobacillus plantarum strains and antimicrobial properties of L. plantarum small heat shock proteins
No full textThe aim of this study was to investigate Lactobacillus plantarum strains possessing antimicrobial features to be proposed as potential bioagents and biopreservant stains that could prevent the growth of pathogenic bacteria in fermented food. A total of 85 Lactobacillus plantarum strains, including strains overproducing small heat shock proteins, were investigated for their antimicrobial activity against the pathogenic bacteria Escherichia coli O157:H7, Staphylococcus aureus, Listeria monocytogenes and Salmonella enterica. Firstly, the antimicrobial effect was evaluated using over-night cultures (ONC) of lactobacilli by agar spot test. The antagonistic effects of L. plantarum strains against pathogens were detected measuring the growth inhibition halos on plates. All strains showed significant antibacterial activity and we classified L. plantarum strains as no, mild, strong and very strong inhibiting strain when inhibitions zone of 1 mm, 2 mm, 2-5 mm and more than 5 mm were produced. Subsequentially, 15 strains showing strong and very strong antimicrobial activity were selected and their cell-free supernatant (CFS) was harvested and used for agar diffusion and microdilution bioassays over an incubation time of 24 h at 30 °C, in order to investigate the substances determining the antimicrobial ability. Overall, the results showed an interesting antagonism depending both on L. plantarum strain analysed and pathogens bacteria tested. Moreover, antimicrobial activity was observed by L. plantarum strains overproducing small heat shock proteins. The applications of L. plantarum strains exhibiting antimicrobial activity need to be considered as safety bio-alternative to traditional antibiotics used against human infection and to chemical substances used in the food processing
Antimicrobial activity of lactic acid bacteria on biofilm formed by Listeria monocytogenes
No full textLactic acid bacteria are proposed as an innovative eco-friendly strategy to control relevant food-borne pathogens including Listeria monocytogenes and L. monocytogenes represent a safety concern for the food industry due to its ability to survive and grow under several harsh conditions associated with food processing and preservation. In addition, L. monocytogenes may persist in food plants and equipment since able to form biofilms. In the present work, we screened 152 lactic acid bacteria for their ability to inhibit the growth of L. monocytogenes serovar 1⁄2a and 4b from animal and vegetable origin. The antagonistic effect was investigated by analysing the halo of inhibition on agar plates co-inoculated with LAB strains or in presence of the correspondent cell-free supernatant. The same approach was employed to evaluate the reduction of biofilm formation on glass, polystirene, and stainless steel. L. monocytogenes biofilms were quantified spectrophotometrically and the viability of the pathogen assessed by qPCR. LAB were clustered in four categories according to their inhibitor effect. The strains with the stronger antagonistic activity suggest a potential employment to control L. monocytogenes proliferation and the corresponding biofilm formation in food processing and plants
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