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Keywords: Exploratory-analysis  or metagenomics  or Chip-seq  or Babraham Institute 


Chip-seq: Motif Analysis Tutorial

Introduction Goal The aim is to : Get familiar with motif analysis of ChIP-seq data. Learn de novo motif discovery methods. In practice : Motif discovery with peak-motifs Differential analysis Random controls

Keywords: Chip-seq, Motif analysis, NGS, Pattern recognition

Chip-seq: Motif Analysis Tutorial https://tess.elixir-europe.org/materials/chip-seq-motif-analysis-tutorial Introduction Goal The aim is to : Get familiar with motif analysis of ChIP-seq data. Learn de novo motif discovery methods. In practice : Motif discovery with peak-motifs Differential analysis Random controls Chip-seq, Motif analysis, NGS, Pattern recognition
Chip-seq: Functional Annotation tutorial

Global Objective Given a set of ChIP-seq peaks annotate them in order to find associated genes, genomic categories and functional terms.

Keywords: Chip-seq, Functional Annotation, NGS

Chip-seq: Functional Annotation tutorial https://tess.elixir-europe.org/materials/chip-seq-functional-annotation-tutorial Global Objective Given a set of ChIP-seq peaks annotate them in order to find associated genes, genomic categories and functional terms. Chip-seq, Functional Annotation, NGS
Chip-seq: Pattern Analysis tutorial

Goal The aim is to : Get familiar with motif analysis of ChIP-seq data. Learn de novo motif discovery methods. In practice : Motif discovery with peak-motifs Differential analysis Random controls

Keywords: Chip-seq, NGS, Pattern recognition

Chip-seq: Pattern Analysis tutorial https://tess.elixir-europe.org/materials/chip-seq-pattern-analysis-tutorial Goal The aim is to : Get familiar with motif analysis of ChIP-seq data. Learn de novo motif discovery methods. In practice : Motif discovery with peak-motifs Differential analysis Random controls Chip-seq, NGS, Pattern recognition
Chip-seq: Peak calling tutorial

The aim is to : Understand how to process reads to obtain peaks (peak-calling). Become familiar with differential analysis of peaks In practice : Obtain dataset from GEO Analyze mapped reads Obtain set(s) of peaks, handle replicates Differential analysis of peak

Keywords: Chip-seq, NGS, Peak calling

Chip-seq: Peak calling tutorial https://tess.elixir-europe.org/materials/chip-seq-peak-calling-tutorial The aim is to : Understand how to process reads to obtain peaks (peak-calling). Become familiar with differential analysis of peaks In practice : Obtain dataset from GEO Analyze mapped reads Obtain set(s) of peaks, handle replicates Differential analysis of peak Chip-seq, NGS, Peak calling
Chip Seq: Annotation and visualization Lesson

How to add biological meaning to peaks

Keywords: Annotation, Chip-seq, Data Visualization, NGS

Chip Seq: Annotation and visualization Lesson https://tess.elixir-europe.org/materials/chip-seq-annotation-and-visualization-lesson How to add biological meaning to peaks Annotation, Chip-seq, Data Visualization, NGS
Chip-seq Analysis

Quality, normalisation and peak calling

Keywords: Chip-seq, Genomics

Chip-seq Analysis https://tess.elixir-europe.org/materials/chip-seq-analysis Quality, normalisation and peak calling Chip-seq, Genomics
Chip Seq: Annotation and visualization Tutorial

Global Objective Given a set of ChIP-seq peaks annotate them in order to find associated genes, genomic categories and functional terms.

Keywords: Annotation, Chip-seq, Data Visualization, NGS

Chip Seq: Annotation and visualization Tutorial https://tess.elixir-europe.org/materials/chip-seq-annotation-and-visualization-tutorial Global Objective Given a set of ChIP-seq peaks annotate them in order to find associated genes, genomic categories and functional terms. Annotation, Chip-seq, Data Visualization, NGS
Quality Control in Sequencing Experiments

This course looks at the different ways in which sequencing based studies can fail and the options for visualisation and QC which allow you to identify and diagnose these failures at an early stage. It is designed to be of use to anyone who is using sequencing as part of their research, not just...

Scientific topics: Quality affairs

Keywords: Babraham Institute

Quality Control in Sequencing Experiments https://tess.elixir-europe.org/materials/quality-control-in-sequencing-experiments This course looks at the different ways in which sequencing based studies can fail and the options for visualisation and QC which allow you to identify and diagnose these failures at an early stage. It is designed to be of use to anyone who is using sequencing as part of their research, not just those who are running sequencing facilities. Quality affairs Babraham Institute
Extracting biological information from gene lists

Many experimental designs end up producing lists of hits, usually based around genes or transcripts. Sometimes these lists are small enough that they can be examined individually, but often it is useful to do a more structured functional analysis to try to automatically determine any interesting...

Keywords: Functional analysis, Gene lists, Babraham Institute

Extracting biological information from gene lists https://tess.elixir-europe.org/materials/extracting-biological-information-from-gene-lists Many experimental designs end up producing lists of hits, usually based around genes or transcripts. Sometimes these lists are small enough that they can be examined individually, but often it is useful to do a more structured functional analysis to try to automatically determine any interesting biological themes which turn up in the lists. This course looks at the various software packages, databases and statistical methods which may be of use in performing such an analysis. As well as being a practical guide to performing these types of analysis the course will also look at the types of artefacts and bias which can lead to false conclusions about functionality and will look at the appropriate ways to both run the analysis and present the results for publication. Functional analysis, Gene lists, Babraham Institute
Sample size estimation

Power analysis is a method to estimate the samples sizes needed to detect statistical effects with high probability. This course provides an introduction to the basic principles of power analysis and goes through the variables for power calculation. It also addresses the issues associated with...

Keywords: Power analysis, Sample size, Babraham Institute

Sample size estimation https://tess.elixir-europe.org/materials/sample-size-estimation Power analysis is a method to estimate the samples sizes needed to detect statistical effects with high probability. This course provides an introduction to the basic principles of power analysis and goes through the variables for power calculation. It also addresses the issues associated with technical and biological replicates. The program is intended for people who have no prior knowledge of power. Basic statistical knowledge is extremely useful but prior attendance on a statistics course is not compulsary. Power analysis, Sample size, Babraham Institute
Statistical Analysis using SPSS

Statistics are an important part of most modern studies and being able to effectively use a statistics package can help you to understand your results. This course provides an introduction to statistics illustrated though the use of the friendly SPSS package.

Scientific topics: Statistics and probability

Keywords: Babraham Institute

Statistical Analysis using SPSS https://tess.elixir-europe.org/materials/statistical-analysis-using-spss Statistics are an important part of most modern studies and being able to effectively use a statistics package can help you to understand your results. This course provides an introduction to statistics illustrated though the use of the friendly SPSS package. Statistics and probability Babraham Institute
Statistical Analysis using GraphPad Prism

GraphPad Prism is a powerful and friendly package which allows you to plot and analyse your data. This course acts not only as an introduction to Prism, but also goes through the basic statistical knowledge which should allow you to make the most of your data.

Keywords: GraphPad Prism, Babraham Institute

Statistical Analysis using GraphPad Prism https://tess.elixir-europe.org/materials/statistical-analysis-using-graphpad-prism GraphPad Prism is a powerful and friendly package which allows you to plot and analyse your data. This course acts not only as an introduction to Prism, but also goes through the basic statistical knowledge which should allow you to make the most of your data. GraphPad Prism, Babraham Institute
Scientific Figure Design

This course provides a practical guide to producing figures for use in reports and publications. It is a wide ranging course which looks at how to design figures to clearly and fairly represent your data, the practical aspects of graph creation, the allowable manipulation of bitmap images and...

Scientific topics: Data visualisation

Keywords: Figure design, Babraham Institute

Scientific Figure Design https://tess.elixir-europe.org/materials/scientific-figure-design This course provides a practical guide to producing figures for use in reports and publications. It is a wide ranging course which looks at how to design figures to clearly and fairly represent your data, the practical aspects of graph creation, the allowable manipulation of bitmap images and compositing and editing of final figures. The course will use a number of different open source software packages and is illustrated with a number of example figures adapted from common analysis tools. Data visualisation Figure design, Babraham Institute
An Introduction to Unix

Increasing amounts of bioinformatics work is done in a command line unix environment. Most large scale processing applications are written for unix and most large scale compute environments are also based on this. This course provides an introduction to the concepts of unix and provides a...

Keywords: Unix, Babraham Institute

An Introduction to Unix https://tess.elixir-europe.org/materials/an-introduction-to-unix Increasing amounts of bioinformatics work is done in a command line unix environment. Most large scale processing applications are written for unix and most large scale compute environments are also based on this. This course provides an introduction to the concepts of unix and provides a practical introduction to working in this environment. Internally we link this course to a more specific course illustrating the use of our internal cluster environment and this part of the course could be adapted for other sites with different compute infrastructure. Unix, Babraham Institute
An Introduction to ggplot

Ggplot is the most popular plotting extension to R and replicates many of the graph types found in the core plotting libraries. This course provides an introduction to the ggplot2 libraries and gives a practical guide for how to use these to create different types of graphs.

Keywords: ggPlot, Babraham Institute

An Introduction to ggplot https://tess.elixir-europe.org/materials/an-introduction-to-ggplot Ggplot is the most popular plotting extension to R and replicates many of the graph types found in the core plotting libraries. This course provides an introduction to the ggplot2 libraries and gives a practical guide for how to use these to create different types of graphs. ggPlot, Babraham Institute
Plotting complex figures with R

This course is a comprehensive guide to the use of the built in R plotting functionality to construct everything from customised simple plots to complex multi-layered figures. It follows on from the material in our introductory R course and participants are expected to have a basic understanding...

Keywords: Graph plotting, R Programming, Babraham Institute

Plotting complex figures with R https://tess.elixir-europe.org/materials/plotting-complex-figures-with-r This course is a comprehensive guide to the use of the built in R plotting functionality to construct everything from customised simple plots to complex multi-layered figures. It follows on from the material in our introductory R course and participants are expected to have a basic understanding of R - enough to load and do basic manipulation of datasets. Graph plotting, R Programming, Babraham Institute
Advanced R

This course follows on from the introductory course. It goes into more detail on practical guides to filtering and combining complex data sets. It also looks at other core R concepts such as looping with apply statements and using packages. Finally it looks at how to document your R analyses and...

Keywords: R programming, Babraham Institute

Advanced R https://tess.elixir-europe.org/materials/advanced-r This course follows on from the introductory course. It goes into more detail on practical guides to filtering and combining complex data sets. It also looks at other core R concepts such as looping with apply statements and using packages. Finally it looks at how to document your R analyses and generate complete analysis reports. R programming, Babraham Institute
Introduction to R

R is a popular language and environment that allows powerful and fast manipulation of data, offering many statistical and graphical options. This course aims to introduce R as a tool for statistics and graphics, with the main aim being to become comfortable with the R environment. It will focus...

Scientific topics: Software engineering

Keywords: R programming, Babraham Institute

Introduction to R https://tess.elixir-europe.org/materials/introduction-to-r R is a popular language and environment that allows powerful and fast manipulation of data, offering many statistical and graphical options. This course aims to introduce R as a tool for statistics and graphics, with the main aim being to become comfortable with the R environment. It will focus on entering and manipulating data in R and producing simple graphs. A few functions for basic statistics will be briefly introduced, but statistical functions will not be covered in detail. Software engineering R programming, Babraham Institute
Learning to Program with Perl

This course aims to introduce the basic features of the Perl language. At the end you should have everything you need to write moderately complicated programs, and enough pointers to other resources to get you started on bigger projects. The course tries to provide a grounding in the basic theory...

Keywords: perl, Babraham Institute

Learning to Program with Perl https://tess.elixir-europe.org/materials/learning-to-program-with-perl This course aims to introduce the basic features of the Perl language. At the end you should have everything you need to write moderately complicated programs, and enough pointers to other resources to get you started on bigger projects. The course tries to provide a grounding in the basic theory you'll need to write programs in any language as well as an appreciation for the right way to do things in Perl. perl, Babraham Institute
Analysing Mapped Sequence Data with SeqMonk

SeqMonk is a program which can analyse large data sets of mapped genomic positions. It is most commonly used to work with data coming from high-throughput sequencing pipelines. The program allows you to view your reads against an annotated genome and to quantitate and filter your data to let...

Scientific topics: Sequence alignment

Keywords: Babraham Institute

Analysing Mapped Sequence Data with SeqMonk https://tess.elixir-europe.org/materials/analysing-mapped-sequence-data-with-seqmonk SeqMonk is a program which can analyse large data sets of mapped genomic positions. It is most commonly used to work with data coming from high-throughput sequencing pipelines. The program allows you to view your reads against an annotated genome and to quantitate and filter your data to let you identify regions of interest. It is a friendly way to explore and analysis very large datasets. This course provides an introduction to the main features of SeqMonk and will run through the anlaysis of a couple of different datasets to show what sort of analysis options it provides. Sequence alignment Babraham Institute
Who is doing what on the cheese surface? Overview of the cheese microbial ecosystem functioning by metatranscriptomic analyses

Cheese ripening is a complex biochemical process driven by microbial communities composed of both eukaryotes and prokaryotes. Surface-ripened cheeses are widely consumed all over the world and are appreciated for their characteristic flavor. Microbial community composition has been studied for a...

Keywords: metagenomics

Who is doing what on the cheese surface? Overview of the cheese microbial ecosystem functioning by metatranscriptomic analyses https://tess.elixir-europe.org/materials/who-is-doing-what-on-the-cheese-surface-overview-of-the-cheese-microbial-ecosystem-functioning-by-metatranscriptomic-analyses-55c4b5d0-ba6e-4ae0-879f-7bc27c10b3eb Cheese ripening is a complex biochemical process driven by microbial communities composed of both eukaryotes and prokaryotes. Surface-ripened cheeses are widely consumed all over the world and are appreciated for their characteristic flavor. Microbial community composition has been studied for a long time on surface-ripened cheeses, but only limited knowledge has been acquired about its in situ metabolic activities. We used an iterative sensory procedure to select a simplified microbial consortium, composed of only nine species (three yeasts and six bacteria), producing the odor of Livarot-type cheese when inoculated in a sterile cheese curd. All the genomes were sequenced in order to determine the functional capacities of the different species and facilitate RNA-Seq data analyses. We followed the ripening process of experimental cheeses made using this consortium during four weeks, by metatranscriptomic and biochemical analyses. By combining all of the data, we were able to obtain an overview of the cheese maturation process and to better understand the metabolic activities of the different community members and their possible interactions. We next applied the same approach to investigate the activity of the microorganisms in real cheeses, namely Reblochon-style cheeses. This provided useful insights into the physiological changes that occur during cheese ripening, such as changes in energy substrates, anabolic reactions, or stresses. metagenomics 2016-12-15 2017-01-11
Soil metagenomics, potential and pitfalls

The soil microorganisms are responsible for a range of critical functions including those that directly affect our quality of life (e.g., antibiotic production and resistance – human and animal health, nitrogen fixation -agriculture, pollutant degradation – environmental bioremediation)....

Keywords: metagenomics

Soil metagenomics, potential and pitfalls https://tess.elixir-europe.org/materials/soil-metagenomics-potential-and-pitfalls-04d3bb46-36ba-47c0-9993-9c7d0aacad32 The soil microorganisms are responsible for a range of critical functions including those that directly affect our quality of life (e.g., antibiotic production and resistance – human and animal health, nitrogen fixation -agriculture, pollutant degradation – environmental bioremediation). Nevertheless, genome structure information has been restricted by a large extent to a small fraction of cultivated species. This limitation can be circumvented now by modern alternative approaches including metagenomics or single cell genomics. Metagenomics includes the data treatment of DNA sequences from many members of the microbial community, in order to either extract a specific microorganism’s genome sequence or to evaluate the community function based on the relative quantities of different gene families. In my talk I will show how these metagenomic datasets can be used to estimate and compare the functional potential of microbial communities from various environments with a special focus on antibiotic resistance genes. However, metagenomic datasets can also in some cases be partially assembled into longer sequences representing microbial genetic structures for trying to correlate different functions to their co-location on the same genetic structure. I will show how the microbial community composition of a natural grassland soil characterized by extremely high microbial diversity could be managed for sequentially attempt to reconstruct some bacterial genomes. Metagenomics can also be used to exploit the genetic potential of environmental microorganisms. I will present an integrative approach coupling rrs phylochip and high throughput shotgun sequencing to investigate the shift in bacterial community structure and functions after incubation with chitin. In a second step, these functions of potential industrial interest can be discovered by using hybridization of soil metagenomic DNA clones spotted on high density membranes by a mix of oligonucleotide probes designed to target genes encoding for these enzymes. After affiliation of the positive hybridizing spots to the corresponding clones in the metagenomic library the inserts are sequenced, DNA assembled and annotated leading to identify new coding DNA sequences related to genes of interest with a good coverage but a low similarity against closest hits in the databases confirming novelty of the detected and cloned genes. metagenomics 2016-12-16 2017-01-11
Welcome message

Presentation of the workshop (Chairman: Claudine Médigue)

Keywords: metagenomics

Welcome message https://tess.elixir-europe.org/materials/welcome-message-69dc597e-f839-448f-9c9d-3622ddffd592 Presentation of the workshop (Chairman: Claudine Médigue) metagenomics 2016-12-15 2017-01-11
From Samples to Data : Assuring Downstream Analysis with Upstream Planning

Metagenomic studies have gained increasing popularity in the years since the introduction of next generation sequencing. NGS allows for the production of millions of reads for each sample without the intermediate step of cloning. However, just as in the past, the quality of the data generate by...

Keywords: metagenomics

From Samples to Data : Assuring Downstream Analysis with Upstream Planning https://tess.elixir-europe.org/materials/from-samples-to-data-assuring-downstream-analysis-with-upstream-planning-6fac0f49-b453-4c15-a409-9753fb27ee9b Metagenomic studies have gained increasing popularity in the years since the introduction of next generation sequencing. NGS allows for the production of millions of reads for each sample without the intermediate step of cloning. However, just as in the past, the quality of the data generate by this powerful technology depends on sample preparation, library construction and the selection of appropriate sequencing technology and sequencing depth. Here we explore the different variables involved in the process of preparing samples for sequencing analysis including sample collection, DNA extraction and library construction. We also examine the various sequencing technologies deployed for routine metagenomic analysis and considerations for their use in different model systems including humans, mouse and the environment. Future developments such as long-reads will also be discussed to provide a complete picture of important aspects prior to data analyses which play a critical role in the success of metagenomic studies. metagenomics 2017-01-11
Sequencing 6000 chloroplast genomes : the PhyloAlps project

Biodiversity is now commonly described by DNA based approches. Several actors are currently using DNA to describe biodiversity, and most of the time they use different genetic markers that is hampering an easy sharing of the accumulated knowledges. Taxonomists rely a lot on the DNA Barcoding...

Keywords: metagenomics

Sequencing 6000 chloroplast genomes : the PhyloAlps project https://tess.elixir-europe.org/materials/sequencing-6000-chloroplast-genomes-the-phyloalps-project-a2b30d75-061a-4663-a5b8-593842df23bf Biodiversity is now commonly described by DNA based approches. Several actors are currently using DNA to describe biodiversity, and most of the time they use different genetic markers that is hampering an easy sharing of the accumulated knowledges. Taxonomists rely a lot on the DNA Barcoding initiative, phylogeneticists often prefer markers with better phylogenic properties, and ecologists, with the coming of the DNA metabarcoding, look for a third class of markers easiest to amplify from environmental DNA. Nevertheless they have all the same need of the knowledge accumulated by the others. But having different markers means that the sequecences have been got from different individuals in differente lab, following various protocoles. On that base, building a clean reference database, merging for each species all the available markers becomes a challenge. With the phyloAlps project we implement genome skimming at a large scale and propose it as a new way to set up such universal reference database usable by taxonomists, phylogeneticists, and ecologists. The Phyloalps project is producing for each species of the Alpine flora at least a genome skim composed of six millions of 100bp sequence reads. From such data it is simple to extract all chloroplastic, mitochondrial and nuclear rDNA markers commonely used. Moreover, most of the time we can get access to the complete chloroplast genome sequence and to a shallow sequencing of many nuclear genes. This methodes have already been successfully applied to algeae, insects and others animals. With the new single cell sequencing methods it will be applicable to most of the unicellular organisms. The good question is now : Can we consider the genome skimming as the next-generation DNA barcode ? metagenomics 2016-12-16 2017-01-11
Revealing and analyzing microbial networks: from topology to functional behaviors

Understanding the interactions between microbial communities and their environment well enough to be able to predict diversity on the basis of physicochemical parameters is a fundamental pursuit of microbial ecology that still eludes us. However, modeling microbial communities is a complicated...

Keywords: metagenomics

Revealing and analyzing microbial networks: from topology to functional behaviors https://tess.elixir-europe.org/materials/revealing-and-analyzing-microbial-networks-from-topology-to-functional-behaviors-14d83c7f-c5f9-4738-8cd5-42e48a1088f7 Understanding the interactions between microbial communities and their environment well enough to be able to predict diversity on the basis of physicochemical parameters is a fundamental pursuit of microbial ecology that still eludes us. However, modeling microbial communities is a complicated task, because (i) communities are complex, (ii) most are described qualitatively, and (iii) quantitative understanding of the way communities interacts with their surroundings remains incomplete. Within this seminar, we will illustrate two complementary approaches that aim to overcome these points in different manners. metagenomics 2016-12-16 2017-01-11
Reconstructing genomes from metagenomes: The holy grail of microbiology

Shotgun metagenomics provides insights into a larger context of naturally occurring microbial genomes when short reads are assembled into contiguous DNA segments (contigs). Contigs are often orders of magnitude longer than individual sequences, offering improved annotations, and key information...

Keywords: metagenomics

Reconstructing genomes from metagenomes: The holy grail of microbiology https://tess.elixir-europe.org/materials/reconstructing-genomes-from-metagenomes-the-holy-grail-of-microbiology-be78338f-13ef-40d6-92cf-621fbccf8808 Shotgun metagenomics provides insights into a larger context of naturally occurring microbial genomes when short reads are assembled into contiguous DNA segments (contigs). Contigs are often orders of magnitude longer than individual sequences, offering improved annotations, and key information about the organization of genes in cognate genomes. Several factors affect the assembly performance, and the feasibility of the assembly-based approaches varies across environments. However, increasing read lengths, novel experimental approaches, advances in computational tools and resources, and improvements in assembly algorithms and pipelines render the assembly-based metagenomic workflow more and more accessible. The utility of metagenomic assembly remarkably increases when contigs are organized into metagenome-assembled genomes (MAGs). Often-novel MAGs frequently provide deeper insights into bacterial lifestyles that would otherwise remain unknown as evidenced by recent discoveries. The increasing rate of the recovery of MAGs presents new opportunities to link environmental distribution patterns of microbial populations and their functional potential, and transforms the field of microbiology by providing a more complete understanding of the microbial life, ecology, and evolution. metagenomics 2016-12-16 2017-01-11
Rationale and Tools to look for the unknown in (metagenomic) sequence data

The interpretation of metagenomic data (environmental, microbiome, etc, ...) usually involves the recognition of sequence similarity with previously identified (micro-organisms). This is for instance the main approach to taxonomical assignments and a starting point to most diversity analyses....

Keywords: metagenomics

Rationale and Tools to look for the unknown in (metagenomic) sequence data https://tess.elixir-europe.org/materials/rationale-and-tools-to-look-for-the-unknown-in-metagenomic-sequence-data-5dd1e1a8-6db2-4b78-b1fc-60e1a5fbcee8 The interpretation of metagenomic data (environmental, microbiome, etc, ...) usually involves the recognition of sequence similarity with previously identified (micro-organisms). This is for instance the main approach to taxonomical assignments and a starting point to most diversity analyses. When exploring beyond the frontier of known biology, one should expect a large proportion of environmental sequences not exhibiting any significant similarity with known organisms. Notably, this is the case for eukaryotic viruses belonging to new families, for which the proportion of "no match" could reach 90%. Most metagenomics studies tend to ignore this large fraction of sequences that might be the equivalent of "black matter" in Biology. We will present some of the ideas and tools we are using to extract that information from large metagenomics data sets in search of truly unknown microorganisms. One of the tools, "Seqtinizer", an interactive contig selection/inspection interface will also be presented in the context of "pseudo-metagenomic" projects, where the main organism under genomic study (such as sponges or corals) turns out to be (highly) mixed with an unexpected population of food, passing-by, or symbiotic microorganisms. metagenomics 2016-12-16 2017-01-11
Prokaryotic Phylogeny on the Fly: databases and tools for online taxonomic identification

PPF (Prokaryotic Phylogeny on the Fly) is an automated pipeline allowing to compute molecular phylogenies for prokarotic organisms. It is based on a set of specialized databases devoted to SSU rRNA, the most commonly used marker for bacterial txonomic identification. Those databases are splitted...

Keywords: metagenomics

Prokaryotic Phylogeny on the Fly: databases and tools for online taxonomic identification https://tess.elixir-europe.org/materials/prokaryotic-phylogeny-on-the-fly-databases-and-tools-for-online-taxonomic-identification-84732559-32a2-4c4c-9c94-2bd3c3773717 PPF (Prokaryotic Phylogeny on the Fly) is an automated pipeline allowing to compute molecular phylogenies for prokarotic organisms. It is based on a set of specialized databases devoted to SSU rRNA, the most commonly used marker for bacterial txonomic identification. Those databases are splitted into different subsets using phylogenetic information. The procedure for computing a phylogeny is completely automated. Homologous sequence are first recruited through a BLAST search performed on a sequence (or a set of sequences). Then the homologous sequences detected are aligned using one of the multiple sequence alignment programs provided in the pipeline (MAFFT, MUSCLE or CLUSTALO). The alignment is then filtered using BMGE and a Maximum Likelihood (ML) tree is computed using the program FastTree. The tree can be rooted with an outgroup provided by the user and its leaves are coloured with a scheme related to the taxonomy of the sequences. The main advantage provided by PPF is that its databases are generated using a phylogeny-oriented procedure and and therefore much more efficient for phylogentic analyses that "generic" collections such as SILVA (in the case SSU rRNA) por GenBank. It is therefore much more suited to compute prokaryotic molecular phylogenies than related systems such as the Phylogeny.fr online system. PPF can be accessed online at https://umr5558-bibiserv.univ-lyon1.fr/lebibi/PPF-in.cgi metagenomics 2016-12-16 2017-01-11
New perspectives on nitrite-oxidizing bacteria - linking genomes to physiology

It is a generally accepted characteristic of the biogeochemical nitrogen cycle that nitrification is catalyzed by two distinct clades of microorganisms. First, ammonia-oxidizing bacteria and archaea convert ammonia to nitrite, which subsequently is oxidized to nitrate by nitrite-oxidizing...

Keywords: metagenomics

New perspectives on nitrite-oxidizing bacteria - linking genomes to physiology https://tess.elixir-europe.org/materials/new-perspectives-on-nitrite-oxidizing-bacteria-linking-genomes-to-physiology-6bc8b25e-043d-47f1-b184-c776d595fb7b It is a generally accepted characteristic of the biogeochemical nitrogen cycle that nitrification is catalyzed by two distinct clades of microorganisms. First, ammonia-oxidizing bacteria and archaea convert ammonia to nitrite, which subsequently is oxidized to nitrate by nitrite-oxidizing bacteria (NOB). The latter were traditionally perceived as physiologically restricted organisms and were less intensively studied than other nitrogen-cycling microorganisms. This picture is contrasted by new discoveries of an unexpected high diversity of mostly uncultured NOB and a great physiological versatility, which includes complex microbe-microbe interactions and lifestyles outside the nitrogen cycle. Most surprisingly, close relatives to NOB perform complete nitrification (ammonia oxidation to nitrate), a process that had been postulated to occur under conditions selecting for low growth rates but high growth yields. The existence of Nitrospira species that encode all genes required for ammonia and nitrite oxidation was first detected by metagenomic analyses of an enrichment culture for nitrogen-transforming microorganisms sampled from the anoxic compartment of a recirculating aquaculture system biofilter. Batch incubations and FISH-MAR experiments showed that these Nitrospira indeed formed nitrate from the aerobic oxidation of ammonia, and used the energy derived from complete nitrification for carbon fixation, thus proving that they indeed represented the long-sought-after comammox organisms. Their ammonia monooxygenase (AMO) enzymes were distinct from canonical AMOs, therefore rendering recent horizontal gene transfer from known ammonia-oxidizing microorganisms unlikely. Instead, their AMO displayed highest similarities to the “unusual” particulate methane monooxygenase from Crenothrix polyspora, thus shedding new light onto the function of this sequence group. This recognition of a novel AMO type indicates that a whole group of ammonia-oxidizing microorganisms has been overlooked, and will improve our understanding of the environmental abundance and distribution of this functional group. Data mining of publicly available metagenomes already indicated a widespread occurrence in natural and engineered environments like aquifers and paddy soils, and drinking and wastewater treatment systems. metagenomics 2016-12-16 2017-01-11