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Strain-level diversity impacts cheese rind microbiome assembly and function
ABSTRACTTaxa that are consistently found across microbial communities are often considered members of a core microbiome. One common assumption is that taxonomically identical core microbiomes will have similar dynamics and functions across communities. However, strain-level genomic and phenotypic variation of core taxa could lead to differences in how core microbiomes assemble and function. Using cheese rinds, we tested whether taxonomically identical core microbiomes isolated from distinct locations have similar assembly dynamics and functional outputs. We first isolated the same three bacterial species (Staphylococcus equorum, Brevibacterium auranticum, and Brachybacterium alimentarium) from nine cheeses produced in different regions of the United States and Europe. Comparative genomics identified distinct phylogenetic clusters and significant variation in genome content across the nine core microbiomes. When we assembled each core microbiome with initially identical compositions,...
Profiling of bacterial and fungal communities of Mexican cheeses by high throughput DNA sequencing
Food Research International, 2018
Cheese is a live food whose preparation involves procedures and microbial communities playing an important role for the final product. We characterized the bacterial and fungal diversity of seventeen different Mexican cheeses by highthroughput DNA sequencing of 16S/18S rDNA libraries. We propose the existence of bacterial and fungal core communities, where at genera level, bacteria include Streptococcus spp., Lactococcus spp., Lactobacillus spp., Aerococcus spp., and Weisella spp. while at species level, the fungal community includes Galactomyces reessii, Scheffersomyces stipitis, Saccharomyces cerevisiae (baker's yeast), and S. cerevisiae_rm11-1a. In addition to the bacterial and fungal core communities, we found members of the cheese microbiota that could be associated to other factors of the cheese manufacturing process. Co-occurrence analysis made in this work, indicates that bacterial and fungal communities maintain positive and negative interactions which are important to shape the resident microbial communities in cheeses. This work is a contribution to the description of the microbial diversity found in some Mexican cheeses.
BMC Microbiology, 2022
Background Next-generation sequencing (NGS) methods and especially 16S rRNA gene amplicon sequencing have become indispensable tools in microbial ecology. While they have opened up new possibilities for studying microbial communities, they also have one drawback, namely providing only relative abundances and thus compositional data. Quantitative PCR (qPCR) has been used for years for the quantification of bacteria. However, this method requires the development of specific primers and has a low throughput. The constraint of low throughput has recently been overcome by the development of high-throughput qPCR (HT-qPCR), which allows for the simultaneous detection of the most prevalent bacteria in moderately complex systems, such as cheese and other fermented dairy foods. In the present study, the performance of the two approaches, NGS and HT-qPCR, was compared by analyzing the same DNA samples from 21 Raclette du Valais protected designation of origin (PDO) cheeses. Based on the result...
The Functional Characteristics of Goat Cheese Microbiota from a One-Health Perspective
International Journal of Molecular Sciences
Goat cheese is an important element of the Mediterranean diet, appreciated for its health-promoting features and unique taste. A pivotal role in the development of these characteristics is attributed to the microbiota and its continuous remodeling over space and time. Nevertheless, no thorough study of the cheese-associated microbiota using two metaomics approaches has previously been conducted. Here, we employed 16S rRNA gene sequencing and metaproteomics to explore the microbiota of a typical raw goat milk cheese at various ripening timepoints and depths of the cheese wheel. The 16S rRNA gene-sequencing and metaproteomics results described a stable microbiota ecology across the selected ripening timepoints, providing evidence for the microbiologically driven fermentation of goat milk products. The important features of the microbiota harbored on the surface and in the core of the cheese mass were highlighted in both compositional and functional terms. We observed the rind microbio...
BMC Genomics, 2017
Background: Brevibacterium strains are widely used for the manufacturing of surface-ripened cheeses, contributing to the breakdown of lipids and proteins and producing volatile sulfur compounds and red-orange pigments. The objective of the present study was to perform comparative genomic analyses in order to better understand the mechanisms involved in their ability to grow on the cheese surface and the differences between the strains. Results: The genomes of 23 Brevibacterium strains, including twelve strains isolated from cheeses, were compared for their gene repertoire involved in salt tolerance, iron acquisition, bacteriocin production and the ability to use the energy compounds present in cheeses. All or almost all the genomes encode the enzymes involved in ethanol, acetate, lactate, 4-aminobutyrate and glycerol catabolism, and in the synthesis of the osmoprotectants ectoine, glycine-betaine and trehalose. Most of the genomes contain two contiguous genes encoding extracellular proteases, one of which was previously characterized for its activity on caseins. Genes encoding a secreted triacylglycerol lipase or involved in the catabolism of galactose and D-galactonate or in the synthesis of a hydroxamate-type siderophore are present in part of the genomes. Numerous Fe 3+ /siderophore ABC transport components are present, part of them resulting from horizontal gene transfers. Two cheese-associated strains have also acquired catecholate-type siderophore biosynthesis gene clusters by horizontal gene transfer. Predicted bacteriocin biosynthesis genes are present in most of the strains, and one of the corresponding gene clusters is located in a probable conjugative transposon that was only found in cheese-associated strains. Conclusions: Brevibacterium strains show differences in their gene repertoire potentially involved in the ability to grow on the cheese surface. Part of these differences can be explained by different phylogenetic positions or by horizontal gene transfer events. Some of the distinguishing features concern biotic interactions with other strains such as the secretion of proteases and triacylglycerol lipases, and competition for iron or bacteriocin production. In the future, it would be interesting to take the properties deduced from genomic analyses into account in order to improve the screening and selection of Brevibacterium strains, and their association with other ripening culture components.
A review of the molecular approaches to investigate the diversity and activity of cheese microbiota
Dairy Science & Technology
The cheese microbiota is characterized by the presence of a large variety of bacteria, yeasts, and molds, and many factors influence their growth and survival. The microbial community in cheese at various stages of ripening has been extensively studied by microbiological techniques based on the cultivation of the microorganisms on media and phenotypic or genotypic characterization of a fraction of the community (culture-dependent methods). Culture-independent methods based on DNA or RNA extraction offer the possibility of profiling uncultivable members of the microbial community as well as distinguishing those that are metabolically active. In this review, the status of research on available molecular tools used to characterize the microbiota in the cheese matrix are described and discussed in order to assess the metabolic functionality of the microbial community, its diversity, as well as the identification of species and their comparative quantification. Combining culture-dependent and culture-independent approaches can contribute to improving the strain selection process by understanding the basis of technological performance. Defined starter and adjunct cultures will improve and standardize cheese quality and safety. Future perspectives include the application of methods such as high-throughput quantitative reverse transcription PCR and pyrosequencing to quantify the contribution of the microbial community to cheese ripening. 摘要干酪微生物区域中存在多种细菌、酵母和霉菌,多种因素影响着上述微生物的生长和存活。采用基于微生物在培养基中培养以及群体中部分微生物的表型或遗传型特征的微生物研究技术,已经对干酪成熟的不同阶段中微生物群体,进行了深入研究。基于DNA或RNA提取的非培养方法提供了研究微生物群体中非培养物以及区分那些代谢活跃的微生物的可能。本文中描述和讨论了当前可用于研究干酪中微生物区系的分子工具的研究现状,旨在评价微生物群体的代谢功能性、多样性以及种属的鉴定、相应的定量方法。基于技术特性的理解,培养和非培养研究方法的结合能够改善菌株的选择过程。明确发酵剂和附属发酵剂将改善和标准化干酪的质量和安全性。同时对应用高通量的定量反转录PCR、焦磷酸测序等方法量化微生物群体对干酪成熟的贡献进行了展望。
SSRN Electronic Journal, 2023
Food safety has been a major concern for consumers. Origin of food products matter for consumers such that the quality, reputation, or other special characteristics can be attributed essentially to that origin. While a geographical indication informs consumers for the origin of the product, it develops a competitive advantage for the markets. To detect distinguishing features of dairy products, the microbial composition of its microbiota is one of the emerging areas of interest. Utilizing novel approaches such as Next Generation Sequencing (NGS) technology to decipher the genetic code of 16s rRNA genes to characterize the bacterial population is widely applied. The bacterial microbiota of the herby cheese samples which were collected from Sırnak province in the South Eastern region of Turkey was examined by an NGS approach for purpose of finding geographical indication possibilities. In brief, Firmicutes is the dominant phyla where Lactobacillaceae and Streptococcaceae are abundant families across the analyzed herby cheese microbiota. The most prominent species is Companilactobacillus ginsenosidimutans detected as the dominant member of the bacterial consortia in 16 herby cheese samples. Another remarkable finding reported here is the Weissella jogaejeotgali which was detected in 15 cheese samples. Albeit the abundance of Levilactobacillus koreensis is low at the microbiome level it was identified in four herby cheese samples. As expected, lactic acid bacteria such as Lactobacillus delbrueckii, Lactococcus raffinolactis and Tetragenococcus halophilus were also identified. On the other hand, bacterial diversity and microbial composition among cheese samples are not significantly affected by mixing different herbs on the manufacturing of herby cheeses. To the best of our knowledge, C. ginsenosidimutans, W. jogaejeotgali and L. koreensis are identified and reported for the first time in a dairy product and the bacterial richness and evenness of herby cheese are higher than those of most other cheeses. These findings make the cheeses in the geography where the samples were produced more valuable and provide opportunities for them to receive geographical indications. Thus, it will create added value while marketing the products.
International Journal of Food Microbiology, 2020
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Metagenomics of pasteurized and unpasteurized gouda cheese using targeted 16S rDNA sequencing
BMC Microbiology
Background: The microbiome of cheese is diverse, even within a variety. The metagenomics of cheese is dependent on a vast array of biotic and abiotic factors. Biotic factors include the population of microbiota and their resulting cellular metabolism. Abiotic factors, including the pH, water activity, fat, salt, and moisture content of the cheese matrix, as well as environmental conditions (temperature, humidity, and location of aging), influence the biotic factors. This study assessed the metagenomics of commercial Gouda cheese prepared using pasteurized or unpasteurized cow milk or pasteurized goat milk via 16S rDNA sequencing. Results: Results were analyzed and compared based on milk pasteurization and source, spatial variability (core, outer, and under the rind), and length of aging (2-4 up to 12-18 months). The dominant organisms in the Gouda cheeses, based on percentage of sequence reads identified at the family or genus levels, were Bacillaceae, Lactococcus, Lactobacillus, Streptococcus, and Staphylococcus. More genus-or family-level (e.g. Bacillaceae) identifications were observed in the Gouda cheeses prepared with unpasteurized cow milk (120) compared with those prepared with pasteurized cow milk (92). When assessing influence of spatial variability on the metagenomics of the cheese, more pronounced differences in bacterial genera were observed in the samples taken under the rind; Brachybacterium, Pseudoalteromonas, Yersinia, Klebsiella, and Weissella were only detected in these samples. Lastly, the aging length of the cheese greatly influenced the number of organisms observed. Twenty-seven additional genus-level identifications were observed in Gouda cheese aged for 12-18 months compared with cheese only aged 2-4 months. Conclusions: Collectively, the results of this study are important in determining the typical microbiota associated with Gouda cheese and how the microbiome plays a role in safety and quality.
PLOS One, 2010
Arthrobacter arilaitensis is one of the major bacterial species found at the surface of cheeses, especially in smear-ripened cheeses, where it contributes to the typical colour, flavour and texture properties of the final product. The A. arilaitensis Re117 genome is composed of a 3,859,257 bp chromosome and two plasmids of 50,407 and 8,528 bp. The chromosome shares large regions of synteny with the chromosomes of three environmental Arthrobacter strains for which genome sequences are available: A. aurescens TC1, A. chlorophenolicus A6 and Arthrobacter sp. FB24. In contrast however, 4.92% of the A. arilaitensis chromosome is composed of ISs elements, a portion that is at least 15 fold higher than for the other Arthrobacter strains. Comparative genomic analyses reveal an extensive loss of genes associated with catabolic activities, presumably as a result of adaptation to the properties of the cheese surface habitat. Like the environmental Arthrobacter strains, A. arilaitensis Re117 is well-equipped with enzymes required for the catabolism of major carbon substrates present at cheese surfaces such as fatty acids, amino acids and lactic acid. However, A. arilaitensis has several specificities which seem to be linked to its adaptation to its particular niche. These include the ability to catabolize D-galactonate, a high number of glycine betaine and related osmolyte transporters, two siderophore biosynthesis gene clusters and a high number of Fe 3+ /siderophore transport systems. In model cheese experiments, addition of small amounts of iron strongly stimulated the growth of A. arilaitensis, indicating that cheese is a highly iron-restricted medium. We suggest that there is a strong selective pressure at the surface of cheese for strains with efficient iron acquisition and salt-tolerance systems together with abilities to catabolize substrates such as lactic acid, lipids and amino acids.