461 research outputs found

    Lactic acid bacteria adjunct cultures exert a mitigation effect against spoilage microbiota in fresh cheese

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    Lactic acid bacteria (LAB) have a strong mitigation potential as adjunct cultures to inhibit undesirable bacteria in fermented foods. In fresh cheese with low salt concentration, spoilage and pathogenic bacteria can affect the shelf life with smear on the surface and packaging blowing. In this work, we studied the spoilage microbiota of an Italian fresh cheese to find tailor-made protective cultures for its shelf life improvement. On 14-tested LAB, three of them, namely Lacticaseibacillus rhamnosus LRH05, Latilactobacillus sakei LSK04, and Carnobacterium maltaromaticum CNB06 were the most effective in inhibiting Gram-negative bacteria. These cultures were assessed by the cultivation-dependent and DNA metabarcoding approach using in vitro experiments and industrial trials. Soft cheese with and without adjunct cultures were prepared and stored at 8 and 14 \ub0C until the end of the shelf life in modified atmosphere packaging. Data demonstrated that the use of adjunct cultures reduce and/or modulate the growth of spoilage microbiota at both temperatures. Particularly, during industrial experiments, C. maltaromaticum CNB06 and Lcb. rhamnosus RH05 lowered psychrotrophic bacteria of almost 3 Log CFU/g in a 5-week stored cheese. On the contrary, Llb. sakei LSK04 was able to colonize the cheese but it was not a good candidate for its inhibition capacity. The combined approach applied in this work allowed to evaluate the protective potential of LAB strains against Gram-negative communities

    Genomic Characterization of Dairy Associated Leuconostoc Species and Diversity of Leuconostocs in Undefined Mixed Mesophilic Starter Cultures

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    Undefined mesophilic mixed (DL-type) starter cultures are composed of predominantly Lactococcus lactis subspecies and 1–10% Leuconostoc spp. The composition of the Leuconostoc population in the starter culture ultimately affects the characteristics and the quality of the final product. The scientific basis for the taxonomy of dairy relevant leuconostocs can be traced back 50 years, and no documentation on the genomic diversity of leuconostocs in starter cultures exists. We present data on the Leuconostoc population in five DL-type starter cultures commonly used by the dairy industry. The analyses were performed using traditional cultivation methods, and further augmented by next-generation DNA sequencing methods. Bacterial counts for starter cultures cultivated on two different media, MRS and MPCA, revealed large differences in the relative abundance of leuconostocs. Most of the leuconostocs in two of the starter cultures were unable to grow on MRS, emphasizing the limitations of culture-based methods and the importance of careful media selection or use of culture independent methods. Pan-genomic analysis of 59 Leuconostoc genomes enabled differentiation into twelve robust lineages. The genomic analyses show that the dairy-associated leuconostocs are highly adapted to their environment, characterized by the acquisition of genotype traits, such as the ability to metabolize citrate. In particular, Leuconostoc mesenteroides subsp. cremoris display telltale signs of a degenerative evolution, likely resulting from a long period of growth in milk in association with lactococci. Great differences in the metabolic potential between Leuconostoc species and subspecies were revealed. Using targeted amplicon sequencing, the composition of the Leuconostoc population in the five commercial starter cultures was shown to be significantly different. Three of the cultures were dominated by Ln. mesenteroides subspecies cremoris. Leuconostoc pseudomesenteroides dominated in two of the cultures while Leuconostoc lactis, reported to be a major constituent in fermented dairy products, was only present in low amounts in one of the cultures. This is the first in-depth study of Leuconostoc genomics and diversity in dairy starter cultures. The results and the techniques presented may be of great value for the dairy industry

    Start of SPIDER operation towards ITER neutral beams

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    Heating Neutral Beam (HNB) Injectors will constitute the main plasma heating and current drive tool both in ITER and JT60-SA, which are the next major experimental steps for demonstrating nuclear fusion as viable energy source. In ITER, in order to achieve the required thermonuclear fusion power gain Q=10 for short pulse operation and Q=5 for long pulse operation (up to 3600s), two HNB injectors will be needed [1], each delivering a total power of about 16.5 MW into the magnetically-confined plasma, by means of neutral hydrogen or deuterium particles having a specific energy of about 1 MeV. Since only negatively charged particles can be efficiently neutralized at such energy, the ITER HNB injectors [2] will be based on negative ions, generated by caesium-catalysed surface conversion of atoms in a radio-frequency driven plasma source. A negative deuterium ion current of more than 40 A will be extracted, accelerated and focused in a multi-aperture, multi-stage electrostatic accelerator, having 1280 apertures (~ 14 mm diam.) and 5 acceleration stages (~200 kV each) [3]. After passing through a narrow gas-cell neutralizer, the residual ions will be deflected and discarded, whereas the neutralized particles will continue their trajectory through a duct into the tokamak vessels to deliver the required heating power to the ITER plasma for a pulse duration of about 3600 s. Although the operating principles and the implementation of the most critical parts of the injector have been tested in different experiments, the ITER NBI requirements have never been simultaneously attained. In order to reduce the risks and to optimize the design and operating procedures of the HNB for ITER, a dedicated Neutral Beam Test Facility (NBTF) [4] has been promoted by the ITER Organization with the contribution of the European Union\u2019s Joint Undertaking for ITER and of the Italian Government, with the participation of the Japanese and Indian Domestic Agencies (JADA and INDA) and of several European laboratories, such as IPP-Garching, KIT-Karlsruhe, CCFE-Culham, CEA-Cadarache. The NBTF, nicknamed PRIMA, has been set up at Consorzio RFX in Padova, Italy [5]. The planned experiments will verify continuous HNB operation for one hour, under stringent requirements for beam divergence (< 7 mrad) and aiming (within 2 mrad). To study and optimise HNB performances, the NBTF includes two experiments: MITICA, full-scale NBI prototype with 1 MeV particle energy and SPIDER, with 100 keV particle energy and 40 A current, aiming at testing and optimizing the full-scale ion source. SPIDER will focus on source uniformity, negative ion current density and beam optics. In June 2018 the experimental operation of SPIDER has started

    Human oral isolate Lactobacillus fermentum AGR1487 induces a proinflammatory response in germ-free rat colons

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    Lactobacilli are thought to be beneficial for human health, with lactobacilli-associated infections being confined to immune-compromised individuals. However, Lactobacillus fermentum AGR1487 negatively affects barrier integrity in vitro so we hypothesized that it caused a pro-inflammatory response in the host. We compared germ-free rats inoculated with AGR1487 to those inoculated with another L. fermentum strain, AGR1485, which does not affect in vitro barrier integrity. We showed that rats inoculated with AGR1487 had more inflammatory cells in their colon, higher levels of inflammatory biomarkers, and increased colonic gene expression of pro-inflammatory pathways. In addition, our in vitro studies showed that AGR1487 had a greater capacity to activate TLR signaling and induce pro-inflammatory cytokines in immune cells. This study indicates the potential of strains of the same species to differentially elicit inflammatory responses in the host and highlights the importance of strain characterization in probiotic approaches to treat inflammatory disorders

    Glutamine depletion by crisantaspase hinders the growth of human hepatocellular carcinoma xenografts

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    Background: A subset of human hepatocellular carcinomas (HCC) exhibit mutations of β-catenin gene CTNNB1 and overexpress Glutamine synthetase (GS). The CTNNB1-mutated HCC cell line HepG2 is sensitive to glutamine starvation induced in vitro with the antileukemic drug Crisantaspase and the GS inhibitor methionine-L-sulfoximine (MSO). Methods: Immunodeficient mice with subcutaneous xenografts of the CTNNB1-mutated HCC cell lines HepG2 and HC-AFW1 were treated with Crisantaspase and/or MSO, and tumour growth was monitored. At the end of treatment, tumour weight and histology were assessed. Serum and tissue amino acids were determined by HPLC. Gene and protein expression were estimated with RT-PCR and western blot and GS activity with a colorimetric method. mTOR activity was evaluated from the phosphorylation of p70S6K1. Results: Crisantaspase and MSO depleted serum glutamine, lowered glutamine in liver and tumour tissue, and inhibited liver GS activity. HepG2 tumour growth was significantly reduced by either Crisantaspase or MSO, and completely suppressed by the combined treatment. The combined treatment was also effective against xenografts of the HC-AFW1 cell line, which is Crisantaspase resistant in vitro. Conclusions: The combination of Crisantaspase and MSO reduces glutamine supply to CTNNB1-mutated HCC xenografts and hinders their growth

    The physical demands of mixed martial arts: A narrative review using the ARMSS model to provide a hierarchy of evidence.

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    The physical demands of mixed martial arts (MMA) training and competition is not yet well quantified. The Applied Research Model for the Sport Sciences (ARMSS) provides a framework through which to conduct sport science, determining pertinent questions to test research findings in real-world settings. The aim of this review was to evaluate MMA research within the context of ARMSS to critically analyse our understanding of the physical requirements of MMA training and competition. Research databases were searched, with 70 peer-reviewed articles being discussed in relation to the specific stage of the ARMSS in which their results best fit. MMA research was found to be mostly foundational and descriptive in nature and has generally not developed along systematic lines. The internal and external loads and responses to training and competition have not been adequately identified. Therefore, it is not currently possible to state which variables are key predictors of success, or how coaches can optimally manipulate these variables. We propose that MMA research be refocused to be conducted within ARMSS. Specifically, stage 2 studies describing the physical, physiological and technical demands of MMA training and competition, and stage 3 studies determining the physiological predictors of performance should be initially prioritised

    Anal and oral human papillomavirus (HPV) infection in HIV-infected subjects in northern Italy: a longitudinal cohort study among men who have sex with men

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    <p>Abstract</p> <p>Background</p> <p>A study including 166 subjects was performed to investigate the frequency and persistence over a 6-month interval of concurrent oral and anal Human Papillomavirus (HPV) infections in Human Immunodeficiency Virus (HIV)-infected men who have sex with men (MSM).</p> <p>Methods</p> <p>Patients with no previously documented HPV-related anogenital lesion/disease were recruited to participate in a longitudinal study. Polymerase chain reaction (PCR) was performed to detect HPV from oral and anal swabs and to detect Human Herpes Virus 8 (HHV-8) DNA in saliva on 2 separate specimen series, one collected at baseline and the other collected 6 months later. A multivariate logistic analysis was performed using anal HPV infection as the dependent variable versus a set of covariates: age, HIV plasma viral load, CD4+ count, hepatitis B virus (HBV) serology, hepatitis C virus (HCV) serology, syphilis serology and HHV-8 viral shedding. A stepwise elimination of covariates with a p-value > 0.1 was performed.</p> <p>Results</p> <p>The overall prevalence of HPV did not vary significantly between the baseline and the follow-up, either in the oral (20.1 and 21.3%, respectively) or the anal specimens (88.6 and 86.3%). The prevalence of high-risk (HR) genotypes among the HPV-positive specimens was similar in the oral and anal infections (mean values 24.3% and 20.9%). Among 68 patients with either a HR, low-risk (LR) or undetermined genotype at baseline, 75% had persistent HPV and the persistence rates were 71.4% in HR infections and 76.7% in LR infections. There was a lack of genotype concordance between oral and anal HPV samples. The prevalence of HR HPV in anus appeared to be higher in the younger patients, peaking (> 25%) in the 43-50 years age group. A decrease of the high level of anal prevalence of all genotypes of HPV in the patients > 50 years was evident. HHV-8 oral shedding was positively related to HPV anal infection (p = 0.0046). A significant correlation was found between the persistence of HHV-8 shedding and HIV viral load by logistic bivariate analysis (Odds Ratio of HHV-8 persistence for 1-log increase of HIV viral load = 1.725 ± 0.397, p = 0.018).</p> <p>Conclusions</p> <p>A high prevalence of HPV infection was found in our cohort of HIV-infected MSM, with a negative correlation between anal HPV infection and CD4 cell count.</p

    Genomic copy number variation in Mus musculus.

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    BACKGROUND: Copy number variation is an important dimension of genetic diversity and has implications in development and disease. As an important model organism, the mouse is a prime candidate for copy number variant (CNV) characterization, but this has yet to be completed for a large sample size. Here we report CNV analysis of publicly available, high-density microarray data files for 351 mouse tail samples, including 290 mice that had not been characterized for CNVs previously. RESULTS: We found 9634 putative autosomal CNVs across the samples affecting 6.87% of the mouse reference genome. We find significant differences in the degree of CNV uniqueness (single sample occurrence) and the nature of CNV-gene overlap between wild-caught mice and classical laboratory strains. CNV-gene overlap was associated with lipid metabolism, pheromone response and olfaction compared to immunity, carbohydrate metabolism and amino-acid metabolism for wild-caught mice and classical laboratory strains, respectively. Using two subspecies of wild-caught Mus musculus, we identified putative CNVs unique to those subspecies and show this diversity is better captured by wild-derived laboratory strains than by the classical laboratory strains. A total of 9 genic copy number variable regions (CNVRs) were selected for experimental confirmation by droplet digital PCR (ddPCR). CONCLUSION: The analysis we present is a comprehensive, genome-wide analysis of CNVs in Mus musculus, which increases the number of known variants in the species and will accelerate the identification of novel variants in future studies

    A Prognostic Model for Estimating the Time to Virologic Failure in HIV-1 Infected Patients Undergoing a New Combination Antiretroviral Therapy Regimen

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    <p>Abstract</p> <p>Background</p> <p>HIV-1 genotypic susceptibility scores (GSSs) were proven to be significant prognostic factors of fixed time-point virologic outcomes after combination antiretroviral therapy (cART) switch/initiation. However, their relative-hazard for the time to virologic failure has not been thoroughly investigated, and an expert system that is able to predict how long a new cART regimen will remain effective has never been designed.</p> <p>Methods</p> <p>We analyzed patients of the Italian ARCA cohort starting a new cART from 1999 onwards either after virologic failure or as treatment-naïve. The time to virologic failure was the endpoint, from the 90<sup>th </sup>day after treatment start, defined as the first HIV-1 RNA > 400 copies/ml, censoring at last available HIV-1 RNA before treatment discontinuation. We assessed the relative hazard/importance of GSSs according to distinct interpretation systems (Rega, ANRS and HIVdb) and other covariates by means of Cox regression and random survival forests (RSF). Prediction models were validated via the bootstrap and c-index measure.</p> <p>Results</p> <p>The dataset included 2337 regimens from 2182 patients, of which 733 were previously treatment-naïve. We observed 1067 virologic failures over 2820 persons-years. Multivariable analysis revealed that low GSSs of cART were independently associated with the hazard of a virologic failure, along with several other covariates. Evaluation of predictive performance yielded a modest ability of the Cox regression to predict the virologic endpoint (c-index≈0.70), while RSF showed a better performance (c-index≈0.73, p < 0.0001 vs. Cox regression). Variable importance according to RSF was concordant with the Cox hazards.</p> <p>Conclusions</p> <p>GSSs of cART and several other covariates were investigated using linear and non-linear survival analysis. RSF models are a promising approach for the development of a reliable system that predicts time to virologic failure better than Cox regression. Such models might represent a significant improvement over the current methods for monitoring and optimization of cART.</p
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