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Evgeni Bolotin, Ruth Hershberg
Gene loss is a major contributor to the evolution of bacterial gene content. Gene loss may occur as a result of shifts in environment leading to changes in the intensity and/or directionality of selection applied for the maintenance of specific genes. Gene loss may also occur in a more neutral manner, when gene functions are lost that were not subject to strong selection to be maintained, irrespective of changes to environment. Here, we used a pangenome-based approach to investigate patterns of gene loss across 15 bacterial species...
October 13, 2016: Scientific Reports
Ewelina Stefanovic, Gerald Fitzgerald, Olivia McAuliffe
The Lactobacillus genus represents the largest and most diverse genera of all the lactic acid bacteria (LAB), encompassing species with applications in industrial, biotechnological and medical fields. The increasing number of available Lactobacillus genome sequences has allowed understanding of genetic and metabolic potential of this LAB group. Pangenome and core genome studies are available for numerous species, demonstrating the plasticity of the Lactobacillus genomes and providing the evidence of niche adaptability...
February 2017: Food Microbiology
Val F Lanza, Fernando Baquero, Fernando de la Cruz, Teresa M Coque
MOTIVATION: AccNET (Accessory genome Constellation Network) is a Perl application that aims to compare accessory genomes of a large number of genomic units, both at qualitative and quantitative levels. Using the proteomes extracted from the analysed genomes, AccNET creates a bipartite network compatible with standard network analysis platforms. AccNET allows merging phylogenetic and functional information about the concerned genomes, thus improving the capability of current methods of network analysis...
September 23, 2016: Bioinformatics
Elisa Anastasi, Iain MacArthur, Mariela Scortti, Sonsiray Alvarez, Steeve Giguère, Jose A Vazquez-Boland
We report a comparative study of 29 representative genomes of the animal pathogen Rhodococcus equi The analyses showed that R. equi is genetically homogeneous and clonal, with a large core genome accounting for ≈80% of an isolates' gene content. An open pangenome, even distribution of accessory genes among the isolates, and absence of significant core-genome recombination, indicated that gene gain/loss is a main driver of R. equi genome evolution. Traits previously predicted to be important in R. equi physiology, virulence and niche adaptation were part of the core genome...
September 16, 2016: Genome Biology and Evolution
Afreenish Hassan, Anam Naz, Ayesha Obaid, Rehan Zafar Paracha, Kanwal Naz, Faryal Mehwish Awan, Syed Aun Muhmmad, Hussnain Ahmed Janjua, Jamil Ahmad, Amjad Ali
BACKGROUND: Acinetobacter baumannii has emerged as a significant nosocomial pathogen during the last few years, exhibiting resistance to almost all major classes of antibiotics. Alternative treatment options such as vaccines tend to be most promising and cost effective approaches against this resistant pathogen. In the current study, we have explored the pan-genome of A. baumannii followed by immune-proteomics and reverse vaccinology approaches to identify potential core vaccine targets...
2016: BMC Genomics
Patrick Browne, Hideyuki Tamaki, Nikos Kyrpides, Tanja Woyke, Lynne Goodwin, Hiroyuki Imachi, Suzanna Bräuer, Joseph B Yavitt, Wen-Tso Liu, Stephen Zinder, Hinsby Cadillo-Quiroz
Members of the order Methanomicrobiales are abundant, and sometimes dominant, hydrogenotrophic (H2-CO2 utilizing) methanoarchaea in a broad range of anoxic habitats. Despite their key roles in greenhouse gas emissions and waste conversion to methane, little is known about the physiological and genomic bases for their widespread distribution and abundance. In this study, we compared the genomes of nine diverse Methanomicrobiales strains, examined their pangenomes, reconstructed gene flow and identified genes putatively mediating their success across different habitats...
August 23, 2016: ISME Journal
Shixiang Sun, Jingfa Xiao, Huiyong Zhang, Zhang Zhang
Codon usage bias, as a combined interplay from mutation and selection, has been intensively studied in Escherichia coli. However, codon usage analysis in an E. coli pangenome remains unexplored and the relative importance of mutation and selection acting on core genes and strain-specific genes is unknown. Here we perform comprehensive codon usage analyses based on a collection of multiple complete genome sequences of E. coli. Our results show that core genes that are present in all strains have higher codon usage bias than strain-specific genes that are unique to single strains...
2016: Frontiers in Microbiology
Y Jourdy, N Chatron, M L Carage, M Fretigny, S Meunier, C Zawadzki, V Gay, C Negrier, D Sanlaville, C Vinciguerra
BACKGROUND: Large deletions encompassing both the complete F9 gene and contiguous genes have been detected in patients with severe hemophilia B (HB). Some of these patients present other clinical features, such as intellectual disability (ID). OBJECTIVES/METHODS: In this study, we characterized six unrelated large deletions encompassing F9, by cytogenetic microarray analysis (CMA), to investigate genotype/phenotype correlation. RESULTS: Five of the six patients included in this study presented ID associated with HB...
August 1, 2016: Journal of Thrombosis and Haemostasis: JTH
Stephanie S Porter, Peter L Chang, Christopher A Conow, Joseph P Dunham, Maren L Friesen
The genetic variants that underlie microbial environmental adaptation are key components of models of microbial diversification. Characterizing adaptive variants and the pangenomic context in which they evolve remains a frontier in understanding how microbial diversity is generated. The genomics of rhizobium adaptation to contrasting soil environments is ecologically and agriculturally important because these bacteria are responsible for half of all current biologically fixed nitrogen, yet they live the majority of their lives in soil...
July 15, 2016: ISME Journal
Mario López-Pérez, Francisco Rodriguez-Valera
We have examined a collection of the free-living marine bacterium Alteromonas genomes with cores diverging in average nucleotide identities ranging from 99.98% to 73.35%, i.e., from microbes that can be considered members of a natural clone (like in a clinical epidemiological outbreak) to borderline genus level. The genomes were largely syntenic allowing a precise delimitation of the core and flexible regions in each. The core was 1.4 Mb (ca. 30% of the typical strain genome size). Recombination rates along the core were high among strains belonging to the same species (37...
2016: Genome Biology and Evolution
Freddy Asenjo, Alejandro Olmos, Patricia Henríquez-Piskulich, Victor Polanco, Patricia Aldea, Juan A Ugalde, Annette N Trombert
Background. The honey bee (Apis mellifera) is the most important pollinator in agriculture worldwide. However, the number of honey bees has fallen significantly since 2006, becoming a huge ecological problem nowadays. The principal cause is CCD, or Colony Collapse Disorder, characterized by the seemingly spontaneous abandonment of hives by their workers. One of the characteristics of CCD in honey bees is the alteration of the bacterial communities in their gastrointestinal tract, mainly due to the decrease of Firmicutes populations, such as the Lactobacilli...
2016: PeerJ
Guillaume Holley, Roland Wittler, Jens Stoye
BACKGROUND: High throughput sequencing technologies have become fast and cheap in the past years. As a result, large-scale projects started to sequence tens to several thousands of genomes per species, producing a high number of sequences sampled from each genome. Such a highly redundant collection of very similar sequences is called a pan-genome. It can be transformed into a set of sequences "colored" by the genomes to which they belong. A colored de Bruijn graph (C-DBG) extracts from the sequences all colored k-mers, strings of length k, and stores them in vertices...
2016: Algorithms for Molecular Biology: AMB
Romain Blanc-Mathieu, Hiroyuki Ogata
The order 'Megavirales' represents a group of eukaryotic viruses with a large genome encoding a few hundred up to two thousand five hundred genes. Several members of Megavirales possess genes involved in major DNA repair pathways. Some of these genes were likely inherited from an ancient virus world and some others were derived from the genomes of their hosts. Here we examine molecular phylogenies of key DNA repair enzymes in light of recent hypotheses on the origin of Megavirales, and propose that the last common ancestors of the individual families of the order Megavirales already possessed DNA repair functions to achieve and maintain a moderately large genome and that this repair capacity gradually increased, in a family-dependent manner, during their recent evolution...
June 2016: Current Opinion in Microbiology
Matthias Scholz, Doyle V Ward, Edoardo Pasolli, Thomas Tolio, Moreno Zolfo, Francesco Asnicar, Duy Tin Truong, Adrian Tett, Ardythe L Morrow, Nicola Segata
Identifying microbial strains and characterizing their functional potential is essential for pathogen discovery, epidemiology and population genomics. We present pangenome-based phylogenomic analysis (PanPhlAn;, a tool that uses metagenomic data to achieve strain-level microbial profiling resolution. PanPhlAn recognized outbreak strains, produced the largest strain-level population genomic study of human-associated bacteria and, in combination with metatranscriptomics, profiled the transcriptional activity of strains in complex communities...
May 2016: Nature Methods
Zulema Gómez-Lunar, Ismael Hernández-González, María-Dolores Rodríguez-Torres, Valeria Souza, Gabriela Olmedo-Álvarez
Bacterial genomes undergo numerous events of gene losses and gains that generate genome variability among strains of the same species (microevolution). Our aim was to compare the genomes and relevant phenotypes of three Bacillus coahuilensis strains from two oligotrophic hydrological systems in the Cuatro Ciénegas Basin (México), to unveil the environmental challenges that this species cope with, and the microevolutionary differences in these genotypes. Since the strains were isolated from a low P environment, we placed emphasis on the search of different phosphorus acquisition strategies...
2016: Frontiers in Microbiology
Tong Ding, Kyle A Case, Morrine A Omolo, Holly A Reiland, Zachary P Metz, Xinyu Diao, David J Baumler
Microorganisms have evolved to occupy certain environmental niches, and the metabolic genes essential for growth in these locations are retained in the genomes. Many microorganisms inhabit niches located in the human body, sometimes causing disease, and may retain genes essential for growth in locations such as the bloodstream and urinary tract, or growth during intracellular invasion of the hosts' macrophage cells. Strains of Escherichia coli (E. coli) and Salmonella spp. are thought to have evolved over 100 million years from a common ancestor, and now cause disease in specific niches within humans...
2016: PloS One
Felipe Coutinho, Diogo Antonio Tschoeke, Fabiano Thompson, Cristiane Thompson
Synechococcus is among the most important contributors to global primary productivity. The genomes of several strains of this taxon have been previously sequenced in an effort to understand the physiology and ecology of these highly diverse microorganisms. Here we present a comparative study of Synechococcus genomes. For that end, we developed GenTaxo, a program written in Perl to perform genomic taxonomy based on average nucleotide identity, average amino acid identity and dinucleotide signatures, which revealed that the analyzed strains are drastically distinct regarding their genomic content...
2016: PeerJ
M B Couger, Radwa A Hanafy, Rachel M Mitacek, Connie Budd, Donald P French, Wouter D Hoff, Mostafa S Elshahed, Noha H Youssef
We report the draft genome sequence of Xanthomonas sp. strain Mitacek01, isolated from an indoor environment vending machine surface with frequent human use in Stillwater, Oklahoma, USA, as part of the Student-Initiated Microbial Discovery project. The genome has a total size of 3,617,426 bp and a contig N50 of 1,906,967 bp.
2015: Genome Announcements
David Kamanda Ngugi, Jochen Blom, Ramunas Stepanauskas, Ulrich Stingl
Nitrite-oxidizing bacteria (NOB) of the genus Nitrospina have exclusively been found in marine environments. In the brine-seawater interface layer of Atlantis II Deep (Red Sea), Nitrospina-like bacteria constitute up to one-third of the bacterial 16S ribosomal RNA (rRNA) gene sequences. This is much higher compared with that reported in other marine habitats (~10% of all bacteria), and was unexpected because no NOB culture has been observed to grow above 4.0% salinity, presumably due to the low net energy gained from their metabolism that is insufficient for both growth and osmoregulation...
June 2016: ISME Journal
D V Goryunov, B E Nagaev, M Yu Nikolaev, A V Alexeevski, A V Troitsky
Stability of composition and sequence of genes was shown earlier in 13 mitochondrial genomes of mosses (Rensing, S. A., et al. (2008) Science, 319, 64-69). It is of interest to study the evolution of mitochondrial genomes not only at the gene level, but also on the level of nucleotide sequences. To do this, we have constructed a "nucleotide pangenome" for mitochondrial genomes of 24 moss species. The nucleotide pangenome is a set of aligned nucleotide sequences of orthologous genome fragments covering the totality of all genomes...
November 2015: Biochemistry. Biokhimii︠a︡
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