scholarly journals Sixteen Genome Sequences of Denitrifying Bacteria Assembled from Enriched Cultures of Anaerobic Pig Manure Digestate

2021 ◽  
Vol 10 (39) ◽  
Author(s):  
Xinhui Wang ◽  
Baoyu Xiang ◽  
Menghui Zhang ◽  
Xiaojun Zhang

We report 16 genomes assembled from the metagenome of pig manure digestate enriched with the addition of N 2 O. These denitrifying bacterial genomes all contain the nosZ gene, encoding N 2 O reductase. Their sizes range from 1,902,599 bp to 6,264,563 bp, with completeness of 75.03% to 98.89%, GC contents of 32.86% to 69.66%, and contamination of 0% to 8.4%.

2015 ◽  
Vol 112 (29) ◽  
pp. 9070-9075 ◽  
Author(s):  
Purushottam D. Dixit ◽  
Tin Yau Pang ◽  
F. William Studier ◽  
Sergei Maslov

An approximation to the ∼4-Mbp basic genome shared by 32 strains ofEscherichia colirepresenting six evolutionary groups has been derived and analyzed computationally. A multiple alignment of the 32 complete genome sequences was filtered to remove mobile elements and identify the most reliable ∼90% of the aligned length of each of the resulting 496 basic-genome pairs. Patterns of single base-pair mutations (SNPs) in aligned pairs distinguish clonally inherited regions from regions where either genome has acquired DNA fragments from diverged genomes by homologous recombination since their last common ancestor. Such recombinant transfer is pervasive across the basic genome, mostly between genomes in the same evolutionary group, and generates many unique mosaic patterns. The six least-diverged genome pairs have one or two recombinant transfers of length ∼40–115 kbp (and few if any other transfers), each containing one or more gene clusters known to confer strong selective advantage in some environments. Moderately diverged genome pairs (0.4–1% SNPs) show mosaic patterns of interspersed clonal and recombinant regions of varying lengths throughout the basic genome, whereas more highly diverged pairs within an evolutionary group or pairs between evolutionary groups having >1.3% SNPs have few clonal matches longer than a few kilobase pairs. Many recombinant transfers appear to incorporate fragments of the entering DNA produced by restriction systems of the recipient cell. A simple computational model can closely fit the data. Most recombinant transfers seem likely to be due to generalized transduction by coevolving populations of phages, which could efficiently distribute variability throughout bacterial genomes.


2019 ◽  
Vol 201 (22) ◽  
Author(s):  
Jiuxin Qu ◽  
Neha K. Prasad ◽  
Michelle A. Yu ◽  
Shuyan Chen ◽  
Amy Lyden ◽  
...  

ABSTRACT Conditionally essential (CE) genes are required by pathogenic bacteria to establish and maintain infections. CE genes encode virulence factors, such as secretion systems and effector proteins, as well as biosynthetic enzymes that produce metabolites not found in the host environment. Due to their outsized importance in pathogenesis, CE gene products are attractive targets for the next generation of antimicrobials. However, the precise manipulation of CE gene expression in the context of infection is technically challenging, limiting our ability to understand the roles of CE genes in pathogenesis and accordingly design effective inhibitors. We previously developed a suite of CRISPR interference-based gene knockdown tools that are transferred by conjugation and stably integrate into bacterial genomes that we call Mobile-CRISPRi. Here, we show the efficacy of Mobile-CRISPRi in controlling CE gene expression in an animal infection model. We optimize Mobile-CRISPRi in Pseudomonas aeruginosa for use in a murine model of pneumonia by tuning the expression of CRISPRi components to avoid nonspecific toxicity. As a proof of principle, we demonstrate that knock down of a CE gene encoding the type III secretion system (T3SS) activator ExsA blocks effector protein secretion in culture and attenuates virulence in mice. We anticipate that Mobile-CRISPRi will be a valuable tool to probe the function of CE genes across many bacterial species and pathogenesis models. IMPORTANCE Antibiotic resistance is a growing threat to global health. To optimize the use of our existing antibiotics and identify new targets for future inhibitors, understanding the fundamental drivers of bacterial growth in the context of the host immune response is paramount. Historically, these genetic drivers have been difficult to manipulate precisely, as they are requisite for pathogen survival. Here, we provide the first application of Mobile-CRISPRi to study conditionally essential virulence genes in mouse models of lung infection through partial gene perturbation. We envision the use of Mobile-CRISPRi in future pathogenesis models and antibiotic target discovery efforts.


2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Gyu-Sung Cho ◽  
Olakunle Fagbemigun ◽  
Erik Brinks ◽  
Gbenga A. Adewumi ◽  
Folarin A. Oguntoyinbo ◽  
...  

The genomes of predominant Lactobacillus helveticus, Lactobacillus fermentum, and Lactobacillus delbrueckii strains from fermented nono were sequenced. The genome sizes were 2.1, 1.9, and 1.7 Mbp, respectively, and the GC contents were 36.5%, 51.5%, and 49.7%, respectively. Annotation revealed some genes for bacteriocin and for the potential production of aroma compounds.


mSystems ◽  
2016 ◽  
Vol 1 (6) ◽  
Author(s):  
Aaron Weimann ◽  
Kyra Mooren ◽  
Jeremy Frank ◽  
Phillip B. Pope ◽  
Andreas Bremges ◽  
...  

ABSTRACT Bacteria are ubiquitous in our ecosystem and have a major impact on human health, e.g., by supporting digestion in the human gut. Bacterial communities can also aid in biotechnological processes such as wastewater treatment or decontamination of polluted soils. Diverse bacteria contribute with their unique capabilities to the functioning of such ecosystems, but lab experiments to investigate those capabilities are labor-intensive. Major advances in sequencing techniques open up the opportunity to study bacteria by their genome sequences. For this purpose, we have developed Traitar, software that predicts traits of bacteria on the basis of their genomes. It is applicable to studies with tens or hundreds of bacterial genomes. Traitar may help researchers in microbiology to pinpoint the traits of interest, reducing the amount of wet lab work required. The number of sequenced genomes is growing exponentially, profoundly shifting the bottleneck from data generation to genome interpretation. Traits are often used to characterize and distinguish bacteria and are likely a driving factor in microbial community composition, yet little is known about the traits of most microbes. We describe Traitar, the microbial trait analyzer, which is a fully automated software package for deriving phenotypes from a genome sequence. Traitar provides phenotype classifiers to predict 67 traits related to the use of various substrates as carbon and energy sources, oxygen requirement, morphology, antibiotic susceptibility, proteolysis, and enzymatic activities. Furthermore, it suggests protein families associated with the presence of particular phenotypes. Our method uses L1-regularized L2-loss support vector machines for phenotype assignments based on phyletic patterns of protein families and their evolutionary histories across a diverse set of microbial species. We demonstrate reliable phenotype assignment for Traitar to bacterial genomes from 572 species of eight phyla, also based on incomplete single-cell genomes and simulated draft genomes. We also showcase its application in metagenomics by verifying and complementing a manual metabolic reconstruction of two novel Clostridiales species based on draft genomes recovered from commercial biogas reactors. Traitar is available at https://github.com/hzi-bifo/traitar . IMPORTANCE Bacteria are ubiquitous in our ecosystem and have a major impact on human health, e.g., by supporting digestion in the human gut. Bacterial communities can also aid in biotechnological processes such as wastewater treatment or decontamination of polluted soils. Diverse bacteria contribute with their unique capabilities to the functioning of such ecosystems, but lab experiments to investigate those capabilities are labor-intensive. Major advances in sequencing techniques open up the opportunity to study bacteria by their genome sequences. For this purpose, we have developed Traitar, software that predicts traits of bacteria on the basis of their genomes. It is applicable to studies with tens or hundreds of bacterial genomes. Traitar may help researchers in microbiology to pinpoint the traits of interest, reducing the amount of wet lab work required.


2021 ◽  
Author(s):  
Cristian Javier Caniu

Artificial intelligence-based predictions have emerged as a friendly and reliable tool for the surveillance of the antimicrobial resistance (AMR) worldwide. In this regard, genome databases typically include whole-genome sequencing (WGS) data containing AMR metadata that can be used to train machine learning (ML) models, in order to predict phenotype features from genome samples. In this study, using a Neural Network (NN) architecture and the SGD-ADAM algorithm, we build ML antibiotic resistance models that can predict Minimum Inhibitory Concentrations (MICs) and antimicrobial susceptibility profiles of Salmonella spp. Data analysis was based on 7,268 genomes publicly available in PATRIC database, containing about 75,000 AMR annotations. ML models were built using reference-free k-mer analysis of whole-genome sequences, MIC measurements and susceptibility categories, obtaining robust and accurate results for 9 antibiotics belonging to beta-lactam, fluoroquinolone, phenicol, aminoglycoside, tetracycline and sulphonamide classes. Although the accuracy of predicting the actual MIC reaches modest levels, the within +/- 1 2-fold dilution accuracy per antibiotic reaches significant levels with values that varies from 85% to 95%, with narrow 95% CIs of about 5% and individual accuracies per MIC ≥ 80%. For differentiation between ''susceptible'' and ''resistant'' values, by measuring the accuracy and error of model's susceptibility predictions to different antibiotics, the accuracy is the same as before and ranges from 85% to 95%, with 95% CIs of about 5%, the recall extends from 75% to 85%, the precision from 60% to 90%, whereas the very major error is ≤ 20%. In summary, these results show that NN-based models are able to learn and predict the AMR phenotype from bacterial genomes based on a gene-free k-mer analysis.


Author(s):  
Antonio J. Martín-Galiano ◽  
Ernesto García

Bacteriophages (phages) are viruses that infect bacteria. They are the most abundant biological entity on Earth (current estimates suggest there to be perhaps 1031 particles) and are found nearly everywhere. Temperate phages can integrate into the chromosome of their host, and prophages have been found in abundance in sequenced bacterial genomes. Prophages may modulate the virulence of their host in different ways, e.g., by the secretion of phage-encoded toxins or by mediating bacterial infectivity. Some 70% of Streptococcus pneumoniae (the pneumococcus)—a frequent cause of otitis media, pneumonia, bacteremia and meningitis—isolates harbor one or more prophages. In the present study, over 4000 S. pneumoniae genomes were examined for the presence of prophages, and nearly 90% were found to contain at least one prophage, either defective (47%) or present in full (43%). More than 7000 complete putative integrases, either of the tyrosine (6243) or serine (957) families, and 1210 full-sized endolysins (among them 1180 enzymes corresponding to 318 amino acid-long N-acetylmuramoyl-L-alanine amidases [LytAPPH]) were found. Based on their integration site, 26 different pneumococcal prophage groups were documented. Prophages coding for tRNAs, putative virulence factors and different methyltransferases were also detected. The members of one group of diverse prophages (PPH090) were found to integrate into the 3’ end of the host lytASpn gene encoding the major S. pneumoniae autolysin without disrupting it. The great similarity of the lytASpnand lytAPPH genes (85–92% identity) allowed them to recombine, via an apparent integrase-independent mechanism, to produce different DNA rearrangements within the pneumococcal chromosome. This study provides a complete dataset that can be used to further analyze pneumococcal prophages, their evolutionary relationships, and their role in the pathogenesis of pneumococcal disease.


2018 ◽  
Author(s):  
Donovan H. Parks ◽  
Maria Chuvochina ◽  
David W. Waite ◽  
Christian Rinke ◽  
Adam Skarshewski ◽  
...  

AbstractTaxonomy is a fundamental organizing principle of biology, which ideally should be based on evolutionary relationships. Microbial taxonomy has been greatly restricted by the inability to obtain most microorganisms in pure culture and, to a lesser degree, the historical use of phenotypic properties as the basis for classification. However, we are now at the point of obtaining genome sequences broadly representative of microbial diversity by using culture-independent techniques, which provide the opportunity to develop a comprehensive genome-based taxonomy. Here we propose a standardized bacterial taxonomy based on a concatenated protein phylogeny that conservatively removes polyphyletic groups and normalizes ranks based on relative evolutionary divergence. From 94,759 bacterial genomes, 99 phyla are described including six major normalized monophyletic units from the subdivision of the Proteobacteria, and amalgamation of the Candidate Phyla Radiation into the single phylum Patescibacteria. In total, 73% of taxa had one or more changes to their existing taxonomy.


2020 ◽  
Vol 9 (45) ◽  
Author(s):  
Hanan R. Shehata ◽  
Richmond A. Chandler ◽  
Steven G. Newmaster

ABSTRACT Here, we report the draft genome sequences of Lactobacillus delbrueckii subsp. bulgaricus strains CBC-LB69 and CBC-LB8. The strains were isolated from naturally processed, homemade dairy foods in Bulgaria. The two genome assemblies each resulted in 39 contigs with total lengths of 1,752,493 and 1,759,908 bp and GC contents of 49.80% and 49.90%, respectively.


Proceedings ◽  
2021 ◽  
Vol 66 (1) ◽  
pp. 15
Author(s):  
Stefanía B. Pascal ◽  
Juan R. Lorenzo Lopez ◽  
Paula M. A. Lucchesi ◽  
Alejandra Krüger

Shiga toxin (Stx)-producing Escherichia coli strains are foodborne pathogens that can cause severe human diseases, such as haemorrhagic colitis and haemolytic uraemic syndrome. Stxs are encoded by bacteriophages (Stx phages) which show remarkable variations in genome composition and harbour several genes of unknown function. Recently, a gene encoding a sialate O-acetylesterase (NanS-p) was identified in some relevant Stx2a phages and it was suggested that it could provide advantages for bacterial growth in the gut. The aim of this study was to analyse the presence and sequence of nanS-p genes in available Stx2a phage genomes. A total of 59 DNA sequences of Stx2a phages were extracted from the NCBI GenBank database with the BLAST program using the stx2a sequence from phage 933W as a query sequence, either as complete phage genomes (45) or from bacterial genomes by subsequent analysis with the PHASTER web server (14). Comparative analysis revealed that nanS-p was located downstream of stx2a in all genomes. Twenty different amino acid sequences of NanS-p were identified. Specifically, catalytic esterase domains showed only 11 possible sequences, with differences mainly observed in nine amino acid positions. Sequences corresponding to the N-terminal domain (DUF1737) showed three possible sequences, two of them closely related, while the C-terminal domain was highly variable, with four groups with structural differences. Since sialate O-acetylesterase activity has been determined from particular Stx2a phages, new studies are necessary to evaluate if the NanS-p subtypes identified in the present study also differ in their biological activity.


Author(s):  
Mariela Gutiérrez-Araya ◽  
Kattia Núñez-Montero ◽  
Javier Pizarro-Cerdá ◽  
Laura Chavarría-Pizarro

Strains of the genera Saccharopolyspora and Streptomyces were isolated from Protopolybia sp. and Metapolybia sp. social wasps in Costa Rica. Draft genome sequences were obtained for six isolates, ranging from 6.4 Mb to 9.1 Mb long and having GC contents of 71 to 73%.


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