1,721,008 research outputs found
Whey phage ecology in artisanal traditional ‘’hard’’ cheese: sustainability in dairy production
No full textNatural whey starters can be considered as a lactic acid bacteria culture, indispensable for the production of Italian traditional “hard” cheeses like Trentingrana. Daily maintained in the dairy activity, the main function of this culture is the acidification during the curd formation, having important effects such as whey drainage from the cocked curd and growth inhibition of photogenic and undesirable bacteria. Loss in whey starter fitness is often associated in poor acidification, mainly due to phage infection, that can strongly affect the cheese production and its final quality. Phage contamination in the dairy environment can not be completely eradicated, and there is fundamentally a co-evolution process that drives an ecological balance between phage and its microbial host, especially in whey starters environments. Therefore knowledge on phages community represent an important aspect to reduce lost in cheese production and to maintain quality and excellence in cheese making. To study the phage ecology in Trentingrana production chain, we have collected 400 samples in six Trentingrana dairies distributed on the autonomous province of Trento, Italy. Almost 1800 lactic acid bacteria have been isolated and more than 150 phages retrieved. Characterization of phage biotypes as well as phages genome sequencing is ongoing. The gaining knowledge together with the isolation of performing lactic acid bacteria resistant to phage infection, will be important to avoid milk and cheese spoilage, potentially leading to a more sustainable cheese production
Tanti batteri e tanti formaggi: biodiversità microbica nel latte e nei formaggi tipici trentini
No full textComposition and evolution of ruminal fluid microbiota changes when cattle are moved from a permanent valley-farm to a temporary highland farm
No full textIntroduction: Ruminal microbiota consists in an extremely biodiverse environment, which includes bacteria, archaea, fungi and protozoa. Microbial populations contribute to the health and productivity of ruminants, and shifts when dairy cow changes diet. To this end, we investigated shifts in the ruminal bacterial and fungal communities in two groups of cows, one remaining in the permanent valley farm and the other moving to a summer highland farm. Materials and methods: Twelve healthy Brown-Swiss cows were selected from a permanent valley-farm located in Trentino (Northern East Italy). In summer 2017, 6 of the 12 cows were moved to the temporary summer farm (1,860 m altitude) for three months. The remaining cows stayed in the permanent farm over the entire duration of the study. A total of 60 ruminal fluid samples were collected monthly by using an esophageal probe, processed for microbiological analysis, extracted for genomic DNA, amplified using archaeal and fungal specific primers, sequenced on a MiSeq Illumina platform and analyzed using QIIME 2.0. Results: Ruminal fluid from cows moved to the temporary alpine farm showed increased microbial counts compared to samples collected from the permanent farm over the summer. Illumina data also showed significant changes of microbial and fungal relative abundance in alpine samples: Fibrobacter, Lachnospiraceae, Veillonellaceae and Tenericutes significantly changed among bacteria; Neocallimastigaceae, Didymosphaeriaceae, Dothideomycetes, Podospora, Filobasidium, Vishniacozyma, Basidiomycota, Aspergillus and Wallemia significantly changed among fungi. Both microbiological counts and metagenomics data at the end of summer (after transhumance) regressed to values registered at the beginning of summer (before transhumance), confirming the hypothesis that alpine pasture strongly influences the microbiota composition of ruminal liquid. Conclusions: This is the first study aiming to analyze the microbial evolution of ruminal fluid before, during, and after summer transhumance, and in particular to compare the microbiota of two groups of cows maintained over summer in the permanent farm or in a temporary highland farm, respectively. This research provides a broad picture of microbial populations residing the ruminal fluid of dairy cows reared in the permanent farm or in a temporary alpine farm, demonstrating the influence of diet, in particular of alpine pasture, on the microbial composition
Production of conjugated linoleic acid (CLA): effect of inulin on microbial composition and CLA concentration in a human intestinal model
No full textConjugated linoleic acids (CLAs) show a number of putative health-promoting activities including anti-carcinogenic, anti-adipogenic, anti-diabetogenic, anti-inflammatory and antioxidant actions. CLAs are naturally produced by ruminal bacteria and several studies demonstrate that various lactobacilli and bifidobacteria are also able to produce CLAs in vitro from linoleic acid (LA). However, the ability of the human gut microbiota to produce CLA is less extensively studied. Our hypothesis is that the human gut microbiota is able to convert LA to CLA, and that the readily fermentable fiber inulin would positively modulate the growth of CLA-producing bacteria and, consequently increase the CLA content in the intestine. The capability of the faecal microbiota from five healthy donors to produce CLA was tested in anaerobic batch cultures for 48 hours at pH 5.5 and 6.5. Test treatments were linoleic acid (LA; 1 mg/mL) + bovine serum albumin (BSA; 0.2 mg/mL), and LA (1 mg/mL) + BSA (0.2 mg/mL) + inulin (1%, w/v) compared to a control BSA (0.2 mg/mL) fermentation. The microbial composition was analyzed 0, 24 and 48 hours after starting the fermentation by 16S rRNA gene Illumina MiSeq sequencing (V3-V4 region). CLAs were quantified by Ultra performance liquid chromatography - tandem mass spectrometer (UPLC-MS/MS) and bi-dimensional gas chromatography (GC x GC). The inclusion of LA+BSA+inulin at pH 5.5 significantly increased the relative abundance of Collinsella aerofaciens (p<0.05), and tended to increase the relative abundance of bifidobacteria. LA+BSA+inulin at both pH 5.5 and 6.5 reduced the relative abundance of Parabacteroides, Bilophila, Clostridia and Enterobacteriaceae (p<0.05). The concentration of CLA, in particular the isomer cis9,trans11 C18:2, was significantly higher in the LA+BSA+inulin group at pH 5.5 after 24 and 48 hours fermentation. The data show that the treatment LA+BSA+inulin at pH 5.5 induce substantial changes in microbiota composition, including bifidogenesis and CLA production in a human intestinal microbiota model. The changes of relative abundance detected are consistent with changes in gut bacteria previously linked to human health. Collinsella aerofaciens has been reported for reducing bloating, in particular in subjects suffering from irritable bowel syndrome, while Clostridia, Bilophila and Enterobacteriaceae causes human infections. In addition, the increase of bifidobacteria and LAB, which have previously been shown in vitro to produce CLA, may also be involved in CLA production under simulated cecal microbiome. These preclinical observations warrant confirmation in suitably designed animal and human mechanistic studies
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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