scholarly journals PHAST, PHASTER and PHASTEST: Tools for finding prophage in bacterial genomes

2017 ◽  
Vol 20 (4) ◽  
pp. 1560-1567 ◽  
Author(s):  
David Arndt ◽  
Ana Marcu ◽  
Yongjie Liang ◽  
David S Wishart
Keyword(s):  
Processing Speed ◽  
Bacterial Genome ◽  
Ease Of Use ◽  
Bacterial Genomes ◽  
Graphical Displays ◽  
Processing Times ◽  
Search Tool ◽  
Practical Guidance ◽  
Rapid Processing ◽  
Bacterial Genome Sequencing

Abstract PHAST (PHAge Search Tool) and its successor PHASTER (PHAge Search Tool – Enhanced Release) have become two of the most widely used web servers for identifying putative prophages in bacterial genomes. Here we review the main capabilities of these web resources, provide some practical guidance regarding their use and discuss possible future improvements. PHAST, which was first described in 2011, made its debut just as whole bacterial genome sequencing and was becoming inexpensive and relatively routine. PHAST quickly gained popularity among bacterial genome researchers because of its web accessibility, its ease of use along with its enhanced accuracy and rapid processing times. PHASTER, which appeared in 2016, provided a number of much-needed enhancements to the PHAST server, including greater processing speed (to cope with very large submission volumes), increased database sizes, a more modern user interface, improved graphical displays and support for metagenomic submissions. Continuing developments in the field, along with increased interest in automated phage and prophage finding, have already led to several improvements to the PHASTER server and will soon lead to the development of a successor to PHASTER (to be called PHASTEST).

scholarly journals Serodiagnosis and Bacterial Genome of Helicobacter pylori Infection

Toxins ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 467
Author(s):  
Aina Ichihara ◽  
Hinako Ojima ◽  
Kazuyoshi Gotoh ◽  
Osamu Matsushita ◽  
Susumu Take ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Antibody Titer ◽  
Bacterial Genome ◽  
Serum Antibody ◽  
Gene Mutations ◽  
Bacterial Genomes ◽  
Western Blots ◽  
A Genome ◽  
Vaca Gene ◽  
H Pylori

The infection caused by Helicobacter pylori is associated with several diseases, including gastric cancer. Several methods for the diagnosis of H. pylori infection exist, including endoscopy, the urea breath test, and the fecal antigen test, which is the serum antibody titer test that is often used since it is a simple and highly sensitive test. In this context, this study aims to find the association between different antibody reactivities and the organization of bacterial genomes. Next-generation sequences were performed to determine the genome sequences of four strains of antigens with different reactivity. The search was performed on the common genes, with the homology analysis conducted using a genome ring and dot plot analysis. The two antigens of the highly reactive strains showed a high gene homology, and Western blots for CagA and VacA also showed high expression levels of proteins. In the poorly responsive antigen strains, it was found that the inversion occurred around the vacA gene in the genome. The structure of bacterial genomes might contribute to the poor reactivity exhibited by the antibodies of patients. In the future, an accurate serodiagnosis could be performed by using a strain with few gene mutations of the antigen used for the antibody titer test of H. pylori.

scholarly journals Consistent Metagenome-Derived Metrics Verify and Delineate Bacterial Species Boundaries

mSystems ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Matthew R. Olm ◽  
Alexander Crits-Christoph ◽  
Spencer Diamond ◽  
Adi Lavy ◽  
Paula B. Matheus Carnevali ◽  
...  
Keyword(s):  
Bacterial Diversity ◽  
Ribosomal Proteins ◽  
Large Scale ◽  
Bacterial Species ◽  
Bacterial Genome ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Species Discrimination ◽  
Bacterial Genomes ◽  
Discrimination Power

ABSTRACT Longstanding questions relate to the existence of naturally distinct bacterial species and genetic approaches to distinguish them. Bacterial genomes in public databases form distinct groups, but these databases are subject to isolation and deposition biases. To avoid these biases, we compared 5,203 bacterial genomes from 1,457 environmental metagenomic samples to test for distinct clouds of diversity and evaluated metrics that could be used to define the species boundary. Bacterial genomes from the human gut, soil, and the ocean all exhibited gaps in whole-genome average nucleotide identities (ANI) near the previously suggested species threshold of 95% ANI. While genome-wide ratios of nonsynonymous and synonymous nucleotide differences (dN/dS) decrease until ANI values approach ∼98%, two methods for estimating homologous recombination approached zero at ∼95% ANI, supporting breakdown of recombination due to sequence divergence as a species-forming force. We evaluated 107 genome-based metrics for their ability to distinguish species when full genomes are not recovered. Full-length 16S rRNA genes were least useful, in part because they were underrecovered from metagenomes. However, many ribosomal proteins displayed both high metagenomic recoverability and species discrimination power. Taken together, our results verify the existence of sequence-discrete microbial species in metagenome-derived genomes and highlight the usefulness of ribosomal genes for gene-level species discrimination. IMPORTANCE There is controversy about whether bacterial diversity is clustered into distinct species groups or exists as a continuum. To address this issue, we analyzed bacterial genome databases and reports from several previous large-scale environment studies and identified clear discrete groups of species-level bacterial diversity in all cases. Genetic analysis further revealed that quasi-sexual reproduction via horizontal gene transfer is likely a key evolutionary force that maintains bacterial species integrity. We next benchmarked over 100 metrics to distinguish these bacterial species from each other and identified several genes encoding ribosomal proteins with high species discrimination power. Overall, the results from this study provide best practices for bacterial species delineation based on genome content and insight into the nature of bacterial species population genetics.

scholarly journals Modeling colicin operons as genetic arms in plasmid-genome conflicts

2021 ◽  
Author(s):  
Pavithra Anantharaman Sudhakari ◽  
Bhaskar Chandra Mohan Ramisetty
Keyword(s):  
Negative Selection ◽  
Bacterial Genome ◽  
Evolutionary Perspective ◽  
Bacterial Genomes ◽  
Sequence Analyses ◽  
Agent Based ◽  
Physiological Relevance ◽  
Maintenance Systems ◽  
Selection Of ◽  
Lethal Genes

Plasmids are acellular propagating entities that depend, as molecular parasites, on bacteria for propagation. The conflict between the bacterial genome and the parasitic plasmids allows the emergence of genetic arms such as Colicin (Col) operons. Endonuclease Col operons encode three proteins; an endonuclease colicin (cleaves nucleic acids), an immunity protein (inactivates its cognate colicin), and lysis protein (aids in colicin release via host cell lysis). Col operons are efficient plasmid-maintenance systems; (i) the plasmid cured cells are killed by the colicins; (ii) damaged cells lyse and releases the colicins that eliminate the competitors; and (iii) the released plasmids invade new bacteria. Surprisingly, some bacterial genomes have Col operons. The eco-evolutionary drive and physiological relevance of genomic Col operons are unknown. We investigated plasmidic and genomic Col operons using sequence analyses from an eco-evolutionary perspective. We found 1,248 genomic and plasmidic colicins across 30 bacterial genera. Although 51% of the genomes harbor colicins, the majority of the genomic colicins lacked a functional lysis gene, suggesting the negative selection of lethal genes. The immunity gene of the Col operon protects the cured host thereby eliminating the metabolic burden due to plasmid. We show mutual exclusivity of col operons on genomes and plasmids. We propose anti-addiction hypothesis for genomic colicins. Using a stochastic agent-based model, we show that the genomic colicins confer an advantage to the host genome in terms of immunity to the toxin and elimination of plasmid burden. Col operons are genetic arms that regulate the ecological interplay of bacterial genomes and plasmids.

scholarly journals Bactopia: a flexible pipeline for complete analysis of bacterial genomes

2020 ◽  
Author(s):  
Robert A. Petit ◽  
Timothy D. Read
Keyword(s):  
Standard Procedure ◽  
Bacterial Species ◽  
Bacterial Genome ◽  
Complete Analysis ◽  
Comparative Genomic ◽  
Bacterial Genomes ◽  
Analysis Pipeline ◽  
Genomic Analyses ◽  
Conserved Genes ◽  
Downstream Analysis

AbstractSequencing of bacterial genomes using Illumina technology has become such a standard procedure that often data are generated faster than can be conveniently analyzed. We created a new series of pipelines called Bactopia, built using Nextflow workflow software, to provide efficient comparative genomic analyses for bacterial species or genera. Bactopia consists of a dataset setup step (Bactopia Datasets; BaDs) where a series of customizable datasets are created for the species of interest; the Bactopia Analysis Pipeline (BaAP), which performs quality control, genome assembly and several other functions based on the available datasets and outputs the processed data to a structured directory format; and a series of Bactopia Tools (BaTs) that perform specific post-processing on some or all of the processed data. BaTs include pan-genome analysis, computing average nucleotide identity between samples, extracting and profiling the 16S genes and taxonomic classification using highly conserved genes. It is expected that the number of BaTs will increase to fill specific applications in the future. As a demonstration, we performed an analysis of 1,664 public Lactobacillus genomes, focusing on L. crispatus, a species that is a common part of the human vaginal microbiome. Bactopia is an open source system that can scale from projects as small as one bacterial genome to thousands that allows for great flexibility in choosing comparison datasets and options for downstream analysis. Bactopia code can be accessed at https://www.github.com/bactopia/bactopia.

scholarly journals A Universal, Genomewide GuideFinder for CRISPR/Cas9 Targeting in Microbial Genomes

mSphere ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Michelle Spoto ◽  
Changhui Guan ◽  
Elizabeth Fleming ◽  
Julia Oh
Keyword(s):  
Gene Function ◽  
Large Scale ◽  
Essential Gene ◽  
Bacterial Species ◽  
Bacterial Genome ◽  
Model Organisms ◽  
Design Parameters ◽  
Bacterial Genomes ◽  
Wide Range ◽  
User Friendly

ABSTRACT The CRISPR/Cas system has significant potential to facilitate gene editing in a variety of bacterial species. CRISPR interference (CRISPRi) and CRISPR activation (CRISPRa) represent modifications of the CRISPR/Cas9 system utilizing a catalytically inactive Cas9 protein for transcription repression and activation, respectively. While CRISPRi and CRISPRa have tremendous potential to systematically investigate gene function in bacteria, few programs are specifically tailored to identify guides in draft bacterial genomes genomewide. Furthermore, few programs offer open-source code with flexible design parameters for bacterial targeting. To address these limitations, we created GuideFinder, a customizable, user-friendly program that can design guides for any annotated bacterial genome. GuideFinder designs guides from NGG protospacer-adjacent motif (PAM) sites for any number of genes by the use of an annotated genome and FASTA file input by the user. Guides are filtered according to user-defined design parameters and removed if they contain any off-target matches. Iteration with lowered parameter thresholds allows the program to design guides for genes that did not produce guides with the more stringent parameters, one of several features unique to GuideFinder. GuideFinder can also identify paired guides for targeting multiplicity, whose validity we tested experimentally. GuideFinder has been tested on a variety of diverse bacterial genomes, finding guides for 95% of genes on average. Moreover, guides designed by the program are functionally useful—focusing on CRISPRi as a potential application—as demonstrated by essential gene knockdown in two staphylococcal species. Through the large-scale generation of guides, this open-access software will improve accessibility to CRISPR/Cas studies of a variety of bacterial species. IMPORTANCE With the explosion in our understanding of human and environmental microbial diversity, corresponding efforts to understand gene function in these organisms are strongly needed. CRISPR/Cas9 technology has revolutionized interrogation of gene function in a wide variety of model organisms. Efficient CRISPR guide design is required for systematic gene targeting. However, existing tools are not adapted for the broad needs of microbial targeting, which include extraordinary species and subspecies genetic diversity, the overwhelming majority of which is characterized by draft genomes. In addition, flexibility in guide design parameters is important to consider the wide range of factors that can affect guide efficacy, many of which can be species and strain specific. We designed GuideFinder, a customizable, user-friendly program that addresses the limitations of existing software and that can design guides for any annotated bacterial genome with numerous features that facilitate guide design in a wide variety of microorganisms.

Development of Embedded Laser Marking Controller Based on ARM9

2013 ◽  
Vol 772 ◽  
pp. 407-411
Author(s):  
Yu Fang ◽  
Dong Yun Wang ◽  
Qi Wei Yu ◽  
Yang Xiu Wei
Keyword(s):  
Control Systems ◽  
Processing Speed ◽  
Processing Capacity ◽  
Laser Marking ◽  
Laser Drivers ◽  
Rapid Processing

The existing laser marking control systems are mainly based on PC and PCI laser drivers. PC is used for editing marking information and extracting marking data. The rapid processing capacity of PC makes the laser making machine achieve faster processing speed. However, it cannot be used in the outdoors and bad situations. In older to make the laser marking system widely adapt to various environments, an embedded laser marking controller is developed. It is based on ARM9 and LINUX. It can be easily operated and can achieve wonderful marking.

scholarly journals Operon Prediction for Sequenced Bacterial Genomes without Experimental Information

2006 ◽  
Vol 73 (3) ◽  
pp. 846-854 ◽  
Author(s):  
Nicholas H. Bergman ◽  
Karla D. Passalacqua ◽  
Philip C. Hanna ◽  
Zhaohui S. Qin
Keyword(s):  
Bacterial Genome ◽  
Experimental Information ◽  
Prediction Algorithm ◽  
Comparative Genomic ◽  
Small Subset ◽  
Bacterial Genomes ◽  
Functional Relationships ◽  
Operon Prediction ◽  
Wide Range ◽  
Generic Set

ABSTRACT Various computational approaches have been proposed for operon prediction, but most algorithms rely on experimental or functional data that are only available for a small subset of sequenced genomes. In this study, we explored the possibility of using phylogenetic information to aid in operon prediction, and we constructed a Bayesian hidden Markov model that incorporates comparative genomic data with traditional predictors, such as intergenic distances. The prediction algorithm performs as well as the best previously reported method, with several significant advantages. It uses fewer data sources and so it is easier to implement, and the method is more broadly applicable than previous methods—it can be applied to essentially every gene in any sequenced bacterial genome. Furthermore, we show that near-optimal performance is easily reached with a generic set of comparative genomes and does not depend on a specific relationship between the subject genome and the comparative set. We applied the algorithm to the Bacillus anthracis genome and found that it successfully predicted all previously verified B. anthracis operons. To further test its performance, we chose a predicted operon (BA1489-92) containing several genes with little apparent functional relatedness and tested their cotranscriptional nature. Experimental evidence shows that these genes are cotranscribed, and the data have interesting implications for B. anthracis biology. Overall, our findings show that this algorithm is capable of highly sensitive and accurate operon prediction in a wide range of bacterial genomes and that these predictions can lead to the rapid discovery of new functional relationships among genes.

Explaining Job Searching Through Social Networking Sites

2010 ◽  
Vol 2 (3) ◽  
pp. 1-15 ◽  
Author(s):  
Norazah Mohd Suki ◽  
T. Ramayah ◽  
Michelle Kow Pei Ming
Keyword(s):  
Social Networking ◽  
Job Search ◽  
Social Networking Sites ◽  
Ease Of Use ◽  
Perceived Usefulness ◽  
Equation Modeling ◽  
Online Social Networking ◽  
Job Seekers ◽  
Search Tool ◽  
Job Searching

This paper examines job searching among employed job seekers through the social networking sites. One hundred ninety survey questionnaires were distributed to employed job seekers who have used online social networking sites via the snowball sampling approach. The collected data were analysed using Structural Equation Modeling (SEM) technique via the Analysis of Moment Structure (AMOS 16) computer program. The results showed that perceived usefulness and perceived enjoyment are positively and significantly related to the behavioural intention to use online social networking sites as a job search tool, whereas perceived ease of use is not positively and significantly related. The study implies that the developers of online social networking sites must provide additional useful functionalities or tools to help users with their job searches. These sites must also assure that they do not disclose individuals’ private and confidential information without the consent. The paper provides insight for employed jobseekers by using online social networking sites as a job search tool.

Sign in / Sign up

Export Citation Format

Share Document