27,429 research outputs found

    Azione di batteri lattici su aflatossina M1 in latte

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    ABSTRACT Aflatoxins M1 are secondary metabolites deriving from aflatoxins B1. They are excreted in milk, with a risk for consumers, especially infants, the elderly and immunosuppressed people. There is a need for new methods to reduce aflatoxin M1 in milk and dairy products, especially biological ones, among which detoxification methods based on the action of lactic acid bacteria are object of recent studies. In this thesis, the ability of 27 mesophilic lactobacilli, isolated from pecorino cheese, and 2 reference strains to reduce aflatoxin M1 in sheep’s milk was assessed. Each bacterial strain was tested in milk, pasteurized at 63°C for 30 minutes and added with 500 ng/l of aflatoxin M1. All samples were incubated at 37°C for 24 hours and then frozen at -20°C prior to High Performance Liquid Chromatography (HPLC) analysis. In order to exclude a natural contamination of milk with aflatoxins M1, milk was preliminary examined for its aflatoxin M1 content. As for aflatoxin M1 quantification, a solid phase extraction was applied by means of immunoaffinity columns. The eluate was dried under nitrogen flow at 40°C and diluted in 0.5 ml of mobile phase composed of water and acetonitrile (80/20%), injected and analyzed by HPLC. The preliminary results show that the tested bacterial strains played a different role in detoxifying aflatoxin M1 in milk. Some bacterial strains showed a strong detoxifying aptitude and 7 of 29 bacterial strains showed an aflatoxin M1 decrease greater than 60%. On the other hand, 4 of all investigated bacterial strains had decreases below 30%. Seventeen of 29 bacterial strains showed decreases between 35 and 58%. RIASSUNTO Le aflatossine M1 sono metaboliti secondari derivanti dalle aflatossine B1, riscontrabili in latte proveniente da animali alimentati con mangimi contaminati. A causa della loro tossicità, costituiscono un rischio per la salute del consumatore, specialmente in caso di infanti, anziani e immunodepressi. Per tali motivi è fondamentale ridurre la contaminazione da aflatossine B1 già nei mangimi e investigare metodi di detossificazione delle aflatossine M1 presenti negli alimenti di origine animale, così da avere prodotti sicuri per i consumatori. In questa tesi è stata testata e analizzata la capacità di 27 ceppi di lattobacilli mesofili, isolati da formaggi pecorini, e di 2 ceppi di referenza, di determinare un decremento nel contenuto di aflatossine M1 in latte ovino sperimentalmente contaminato. Per ogni ceppo batterico è stato allestito un campione in latte pastorizzato a 63°C per 30 minuti e addizionato con 500 ng/l di aflatossina M1. In tutti i casi è stata applicata una fase di incubazione a 37°C per 24 ore e successivamente i campioni sono stati congelati a - 20°C in attesa delle successive analisi di quantificazione dell’aflatossina residua. Con il fine di verificare che il latte non fosse naturalmente contaminato, per ogni prova è stato esaminato un campione di latte senza aggiunta di aflatossina M1 e ceppi batterici. Per quanto riguarda la fase di quantificazione dell’aflatossina M1, l’estrazione dei campioni è avvenuta in fase solida, per mezzo di colonnine di immunoaffinità. L’eluito, portato a secco sotto flusso di azoto a 40°C, è stato poi ripreso in 0.5 ml di fase mobile composta da acqua e acetonitrile (80/20%), iniettato e analizzato tramite High Performance Liquid Chromatography (HPLC). Dai risultati si evince che i ceppi batterici in esame hanno avuto un ruolo diversificato nel detossificare il latte dalla aflatossina M1 introdotta. Si è inoltre ricavato che una quota dell’aflatossina introdotta nei campioni viene resa indisponibile probabilmente a causa dei legami con la frazione caseinica del latte. Alcuni ceppi batterici hanno mostrato spiccata attitudine detossificante e, in particolare, dei 29 ceppi investigati 7 hanno determinato un abbattimento superiore al 60%. Al contrario, 4 hanno fatto registrare abbattimenti inferiore al 30%, mentre i restanti 17 ceppi hanno mostrato abbattimenti compresi tra il 35 e il 58%. Da quanto riscontrato da questi dati preliminari, si evince un’attitudine alla detossificazione da parte dei batteri lattici nei confronti dell’aflatossina M1 e una marcata differenza di azione tra i vari ceppi impiegati

    The Mechanism and Potential Therapeutic Effects of Cyclosporin, Cyclophilin, Probiotics and Syndecan-1 in an Animal Model of Inflammatory Bowel Disease

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    Background: Inflammatory bowel diseases (IBDs) have several treatment modalities including immunoregulators, like cyclosporine A, an immunosuppressant that interacts with cytoplasmic cyclophilin A, and probiotics. Aims: This study explored and compared the possible role of syndecan-1 in the IBD pathogenic process as well as the effectiveness of cyclophilin A, cyclosporine A, and their combination in the management of IBDs in the presence of probiotics. Methodology: IBD was induced in a total of 112 mice equally divided between syndecan-1 knock-out (KO) and Balb/c wild-type mice, using 2% dextran sulfate sodium (DSS) followed by intraperitoneal treatment with cyclosporine A, cyclophilin A, or a combination of both. In addition, a daily dose of probiotics was given in their drinking water. The animals were monitored for clinical signs and symptoms and checked for gross pathologies in the abdomen after 3 weeks. Descending and sigmoid colon biopsies were collected and fixed for routine microscopy or frozen for protein extraction and molecular testing for IL-6, CD3, CD147, and beta 1 integrins as well as pAkt expression. Results: The data showed that the induction of IBD in the syndecan-1 KO mice was more severe at the clinical, histological, and molecular levels than in the wild type. The combined CypA-CyA treatment showed no added inhibitory effect compared to single-drug treatment in both strains. Probiotics added to the combination was more effective in the wild type and, when used alone, its inhibition of IL-6 was the highest. As for the CD147 marker, there were more suppressions across the various groups in the KO mice except for the probiotics-alone group. Concerning CD3, it was significantly increased by the CypA-CyA complex, which led to more inflammation in the KO mice. Probiotics had little effect with the combination. In relation to beta 1 integrins, the CypA-CyA combination made no significant difference from CyA alone, and adding probiotics to the combination resulted in higher beta 1 integrin expression in the KO mice. As for pAkt, it was very well expressed and upregulated in both strains treated with DSS, but the effect was much larger in the KO mice. In brief, the CypA-CyA complex showed a decrease in the expression of pAkt, but there was no added effect of both drugs. Probiotics along with the complex had a similar reduction effects in both strains, with a greater effect in the wild-type mice, while probiotics alone led to a similar reduction in pAkt expressions in both strains. Conclusions: The differential effects of CyA, CypA, probiotics, and their combinations on the various inflammatory markers, as well as the histological alterations and clinical signs and symptoms, speak in favor of a clear role of syndecan-1 in reducing inflammation. However, probiotics need to be considered after more explorations into the mechanisms involved in the presence of CypA and CyA especially since pAkt is less active in their presence

    Probiotics and urogenital infections: a protocol for an evidence and gap map

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    This is the final version.Urogenital infections, particularly bacterial vaginosis (BV), vulvovaginal candidiasis (VVC) and urinary tract infections (UTI), are routinely treated with antibiotics. However, there are mounting concerns about the need for alternative or adjunct therapies due to increasing antimicrobial resistance. Probiotics have garnered significant interest both in the scientific community and the public. This is due to their ability to compete with pathogens, hindering their colonization and contributing to host defence mechanisms. However, their effectiveness in the management of urogenital infections in clinical and primary care settings have been inconsistent across clinical studies and systematic reviews. This evidence and gap map (EGM) seeks to offer comprehensive and clearer overviews of probiotics in relation to urogenital infection management. This method ensures an unbiased evaluation of the present body of evidence on probiotic use, consolidating the existing knowledge and identify the knowledge gaps which can inform research, clinical decision-making and healthcare practice policy development

    Treatment of corn with lactic acid delayed in vitro ruminal degradation without compromising fermentation: a biological and morphological monitoring study

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    Grain processed by lactic acid (LA) is known to improve ruminant growth and health. However, the exact mechanism regarding rumen hydrolysis of LA-treated grain is still ambiguous. This experiment was designed to compare the effects of 5% LA treatment on the trophic and morphological variations in corn and to discover the alternations in ruminal hydrolysis between LA-treated and untreated corn macroscopically and microscopically using in vitro fermentation method. The results showed that, compared with untreated corn (CN), corn treated with 5% LA for 48 h (CNLA) experienced a decrease in the dry matter, albumin fraction, aNDFom, and water-soluble carbohydrate content but an increase in the resistant starch content. The in vitro fermentation showed that the pH of CNLA was higher, but dry matter disappearance was lower than that of CN. Most of the fermentation indices were unaffected, except for decreased iso-butyrate and iso-valerate. The abundances of total bacteria, Prevotella spp., Streptococcus bovis, and Selenomonas ruminantium were higher, but those of Ruminococcus flavefaciens and Ruminococcus albus were lower in CNLA than in CN. There were differences in the scanning electron micrographs between CNLA and CN after 3 h of fermentation. This study suggests that treating corn with LA for 48 h can induce changes in its nutrient composition and alter the bacterial flora during subsequent in vitro fermentation. These changes appeared to be crucial contributors to the beneficial effects observed in rumen fermentation

    Total urinary polyphenols and ideal cardiovascular health metrics in Spanish adolescents enrolled in the SI Program: a cross-sectional study

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    To study the relationship between urinary total polyphenol excretion (TPE) in adolescents and ideal cardiovascular (CVH) metrics. 1151 adolescents aged 12.04 (0.46) years participating in the SI! Program for Secondary Schools were selected based on the availability of urine samples and information required to assess CVH metrics. Data on health behaviours (smoking status, body mass index, physical activity, and healthy diet) and health factors (blood pressure, total cholesterol, and blood glucose) were used to calculate the CVH metrics. TPE in urine was analysed by a Folin-Ciocalteu method after solid-phase extraction. Associations between TPE (categorized into tertiles) and CVH metrics (total and separate scores) were assessed using multilevel mixed-effect regression models. Higher TPE levels were associated with higher (healthier) CVH scores and ideal smoking status (OR 1.54, 95% CI 1.10; 1.87, p value = 0.007), physical activity (OR 1.12, 95% CI 1.02; 1.23, p value = 0.022) and total cholesterol (OR 1.78, 95% CI 1.16; 2.73, p value = 0.009) after multivariate adjustment. An association between TPE and total CVH scores was observed only in boys. Girls with higher TPE had higher rates of ideal total cholesterol and blood pressure. According to our findings, higher urinary TPE is related to better CVH scores, with relevant differences in this association by gender

    Inulin supplementation in feed as a prebiotic for red tilapia Oreochromis sp.

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    The objective of this study was to assess the impact of inulin as a prebiotic in feed on red tilapia (Oreochromis sp.) growth performance, hematological parameters, feed utilization, digestive enzyme activity, and the quantity of lactic acid bacteria in the intestine. This study has a fully randomized design with four treatments and three replications, namely inulin at doses of 0, 1, 2, and 4 g/kg feed. One-way ANOVA was used to assess data on growth performance, feed utilization, survival rate, digestive enzyme activity, and the amount of lactic acid bacteria, while the hematological parameters were analyzed descriptively. Red tilapia fry weighing an average of 5.27 ± 0.45 g was raised for 30 days in plastic container containing 40 L of water at a density of 15 fish per container (375 fish/m3). Fish were fed three times a day at satiation. Red tilapia-fed diet supplemented with 4 g/kg inulin of feed had higher body weight increase, protein efficiency ratio, digestive enzyme activity, and amount of lactic acid bacteria while food conversion ratio was lower compared to other treatments (p<0.05). Meanwhile, the specific growth rate and survival rate were not different from the control group. Hematological parameters were within the normal range for all treatments. Thus, the supplementation of inulin in feed of 4 g/kg has the potential as a prebiotic for red tilapia.   Keywords: digestive enzyme activity, inulin, lactic acid bacteria, prebiotic, red tilapia   ABSTRAK   Tujuan dari penelitian ini adalah untuk mengkaji pengaruh inulin sebagai prebiotik pada pakan terhadap kinerja pertumbuhan, parameter hematologi, pemanfaatan pakan, aktivitas enzim pencernaan, dan kuantitas bakteri asam laktat di usus ikan nila merah (Oreochromis sp.). Penelitian ini memiliki rancangan acak lengkap dengan empat perlakuan dan tiga ulangan yaitu inulin dengan dosis 0; 1; 2; dan 4 g inulin/kg pakan. One-way ANOVA digunakan untuk menilai data kinerja pertumbuhan, pemanfaatan pakan, kelangsungan hidup, aktivitas enzim pencernaan, dan jumlah bakteri asam laktat, sedangkan parameter hematologi dianalisis secara deskriptif. Benih ikan nila merah dengan berat rata-rata 5,27 ± 0,45 g dipelihara selama 30 hari dalam wadah plastik dengan volume air 40 L dan kepadatan 15 ekor per wadah (375 ekor/m3). Ikan diberi makan tiga kali sehari secara at satiation. Ikan nila merah yang diberi suplemen inulin 4 g/kg pakan menunjukkan pertumbuhan bobot, rasio efisiensi protein, aktivitas enzim pencernaan, dan jumlah bakteri asam laktat yang lebih besar, sedangkan konversi pakan lebih rendah dibandingkan dengan perlakuan lainnya (p<0,05). Parameter laju pertumbuhan spesifik dan tingkat kelangsungan hidup tidak berbeda dengan kelompok kontrol Parameter hematologi berada dalam kisaran normal untuk semua perlakuan. Suplementasi inulin pada pakan sebanyak 4 g/kg berpotensi sebagai prebiotik ikan nila merah.   Kata kunci: aktivitas enzim pencernaan, bakteri asam laktat, ikan nila merah, inulin, prebioti

    Lactic acid bacteria isolated from traditional and innovative alheiras as potential biocontrol agents

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    From a selection of seven traditional and 14 innovative alheiras, 491 lactic acid bacteria (LAB) were isolated and tested for their antimicrobial activity against several food-borne pathogens. Among these, six strains revealed antimicrobial activity through potential bacteriocin production against 14 Listeria monocytogenes strains, Enterococcus faecalis ATCC 29212, Clostridium sporogenes ESB050, and Clostridium perfringens ESB054. Through whole genome sequencing (WGS), these strains were identified as Lactiplantibacillus plantarum (2), Leuconostoc mesenteroides (1), and Pediococcus acidilactici (3). Furthermore, several orthologues of class II bacteriocins genes were identified, including Plantaricin E, Plantaricin F, Pediocin PA, Enterocin X, Leucocin A, and Coagulin A. No virulence or antibiotic resistance genes’ orthologues were detected by WGS analysis. However, the selected LAB strains showed variable phenotypic patterns related to virulence genes and antibiotic resistance when assessed through classical methodologies. None of these strains demonstrated the production of biogenic amines, gelatinase or DNase. Additionally, no hemolytic activity or lipase enzyme production was observed. However, only Lpb. plantarum 9A3 was sensitive to all tested antibiotics and was thus chosen for further examination. The bacteriocins produced by Lpb. plantarum (9A3) exhibited stability across a broad range of conditions, including temperatures from 4 to 100 °C, pH values ranging from 2 to 8, exposure to surfactants and detergents (Tween 20 and 80, SDS, EDTA 0.1, 2 and 5 mM, urea and sodium deoxycholate), and enzymes (papain and catalase). Their maximum activity (AU/mL = 12,800) against four L. monocytogenes strains was observed between 21 and 36 h of growth of Lbp. plantarum 9A3, indicating a bacteriostatic mode of action. Therefore, this strain appears to be a robust candidate for potential application as a protective strain to be used in the food industry. Not only is it safe, but it also produces stable bacteriocins (harbouring genes encoding for the production of three) effectively inhibiting significant pathogens such as L. monocytogenes and C. perfringens.info:eu-repo/semantics/publishedVersio

    Effect of penicillin in concentration below the sensitivity level of biological methods on yoghurt cultures and yoghurt

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    The study was conducted to examine the effect of penicillin (0.003 IJ ml -1 of milk) in concentration below the sensitivity level of biological methods (Delvo SP and Resasurine test) on yoghurt cultures. According to the results obtained, the stated penicillin concentration prolonged the period of final incubation in the bulk starter (3 h and 20 min) and in yoghurt (3 h and 40 min). The total count of S. thermophilus colonies in the bulk starter and yoghurt is also reduced with a loss of one (log 7.32), that is, two logarithmic numbers (log 6.53) compared with the control samples (without penicillin). The total count of L. bulgaricus colonies was higher in the control samples compared with the experimental samples. Upon the final incubation period and storage for 18 h at 5 °C, there was a drop in the titratable acidity and an increase in pH values of the control samples. Microscopic examination of the control samples showed a gradual disappearance of streptococci with a complete prevalence of lactobacilli in yoghurt. Additionally, morphological changes occurred in streptococci (long chains) and lactobacilli (long and irregular rods)

    Context-Dependent Acquisition of Antimicrobial Resistance Mechanisms

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    Natural transformation is a process whereby bacteria actively take up free DNA from the environment while in a physiological state termed competence. Uptaken DNA is then recombined into the recipient’s genome or reconverted into extra-chromosomal genetic elements. The inducing stimuli for competence vary widely between transformable species and competence induction is affected by a host of abiotic factors found in bacterial environments. Natural transformation is recognised to be responsible for the dissemination of antimicrobial resistance genes both within and between species, contributing to the global antimicrobial resistance crisis threatening modern medicine. Despite being the first mechanism of horizontal gene transfer discovered, the evolutionary benefits of natural transformation are still under debate. This thesis is comprised of four standalone research chapters which aimed 1) to determine if chemotherapeutic compounds affect the transformation frequencies of transformable bacteria. This provides important information which can have implications on the contraction of a life-threatening infection in cancer patients. 2) to determine if other environmentally relevant bacteria affect the transformation frequencies of transformable bacteria. Understanding the contexts under which bacteria transform in their natural environments can help us to predict the spread of antimicrobial resistance mechanisms via natural transformation. 3) to produce a resource of genomic information for the scientific community, allowing researchers to improve our understanding of the Acinetobacter genus. And 4) to determine if environmentally relevant bacteria affect the transformation frequencies of transformable bacteria to find evidence for the sex hypothesis for natural transformation. This was performed by using biotic interactions as a selection pressure and DNA from a range of related species as a substrate for transformation. Together, these chapters provide information about the contexts under which transformation is both regulated and selected for in realistic environmental contexts. Enhancing our understanding of how and when bacteria naturally transform, in both natural and clinical environments, can help us to monitor and establish preventative measures to limit the spread of antimicrobial resistance genes between bacteria

    Tracking the transfer of antimicrobial resistance genes from raw materials to sourdough breads

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    The present study hypothesizes that raw materials used in bread making can transfer antibiotic resistance genes (ARGs) to processed breads. Four types of flour and four types of semolina were purchased from supermarkets and inoculated with a commercial dried sourdough starter to make breads. The microbiological characteristics of all raw materials and fermented doughs were investigated. The levels of yeasts and lactic acid bacteria (LAB) increased up to 107 CFU/g. The values of pH decreased to 4.54–4.86 while total titratable acidity increased inversely. All unprocessed and processed samples, including breads, were analyzed by a molecular approach to detect bacterial and fungal DNAs and 17 antibiotic resistance genes for penicillins, macrolides, tetracyclines, and chloramphenicol. Illumina technology showed that the operational taxonomy units (OTUs) identified from unprocessed wheat milling products, fermented doughs, and baked products mainly belonged to Acetobacteraceae. Enterococci were present in all doughs. After baking, the relative abundance (RA)% of Enterococcus and Acetobacteraceae decreased. The DNA analyzed for fungal composition showed that Kazachstania humilis dominated dried sourdough starter and doughs, and its OTUs were also detected at high RA% in baked products. The search for ARGs revealed that all samples analyzed did not show resistance to penicillins, chloramphenicol, and macrolides. However, three of the semolinas included in this study (S1, S3 and S4) and the corresponding doughs (SD1, SD3 and SD4) were positive for tet(A) and tet(B) resistance genes. This work indicated that breads have a limited role in the dissemination of ARGs
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