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July 7, 2019

It’s more than stamp collecting: how genome sequencing can unify biological research.

The availability of reference genome sequences, especially the human reference, has revolutionized the study of biology. However, while the genomes of some species have been fully sequenced, a wide range of biological problems still cannot be effectively studied for lack of genome sequence information. Here, I identify neglected areas of biology and describe how both targeted species sequencing and more broad taxonomic surveys of the tree of life can address important biological questions. I enumerate the significant benefits that would accrue from sequencing a broader range of taxa, as well as discuss the technical advances in sequencing and assembly methods that would allow for wide-ranging application of whole-genome analysis. Finally, I suggest that in addition to ‘big science’ survey initiatives to sequence the tree of life, a modified infrastructure-funding paradigm would better support reference genome sequence generation for research communities most in need. Copyright © 2015 Elsevier Ltd. All rights reserved.


July 7, 2019

Surveillance of Klebsiella pneumoniae and antibiotic resistance a retrospective and comparative study through a period in Nepal

Among the Enterobacteriacea Klebsiella pneumoniae is for the most part obtained from clinical samples and most probable cause of a typical form of primary pneumonia. It can also responsible for a variety of extrapulmonary infections, counting enteritis and meningitis in infants, urinary tract infections in children and adults and septicaemia in all age groups. Like wise these pathogens are significant cause of hospital acquired infections right through the world. The remarkable increase in the prevalence of antibiotic resistance in bacteria noticed in recent years represents a considerable challenge to public health microbiology worldwide. Klebsiellae have a tendency to possess antibiotic resistant plasmids; as a result, infections with multiple antibiotic-resistant strains can be likely. Only some degree of studies had been accounted in this regard from Nepal. The study was performed from January 1999 to March 2001. To come upon the existing dated antibiotic resistance pattern of Klebsiella pneumoniae. The study was carried out at TUTH laboratory with the objectives to ascertain the prevalence of Klebsiella pneumoniae in conjunction with to calculate the significance antibiotic resistance correlation between various antibiotics. By which the later 15 years analysis of antibiotic resistance was evaluated with comparison to this study.In this scrutiny the result was established that the numbers of total isolates including both klebsiella pneumoniae and other Kebsiella species were 62 from urine samples, 78 from pus samples and 96 from sputum samples and 34 from other miscellaneous samples. In this study positive culture for Klebsiella pneumoniae was 32.83% for sputum samples, 23.62.% for urine samples and 24.57% for pus samples. Majority of the strains isolated were sensitive to ß- lactamases, Floroquinolones, Aminoglycosides, Tetracycline and Cotrimoxazole, combined antibiotics. The current review study from 1999 to 2014 discloses the frequency of infections due to klebsiella pneumoniae strains in the hospitalized patients and their tendency towards antibiotic resistance was on the increase. Large quantity of antibiotics exploited for human therapy has resulted in the selection of pathogenic bacteria resistant to multiple antimicrobial drugs. This has become a vital clinical and infection control challenge, particularly in resource-limited settings with far above the ground a raising rate of antimicrobial resistance.


July 7, 2019

Paenibacillus larvae-directed bacteriophage HB10c2 and its application in American Foulbrood-affected honey bee larvae.

Paenibacillus larvae is the causative agent of American foulbrood (AFB), the most serious honey bee brood bacterial disease. We isolated and characterized P. larvae-directed bacteriophages and developed criteria for safe phage therapy. Whole-genome analysis of a highly lytic virus of the family Siphoviridae (HB10c2) provided a detailed safety profile and uncovered its lysogenic nature and a putative beta-lactamase-like protein. To rate its antagonistic activity against the pathogens targeted and to specify potentially harmful effects on the bee population and the environment, P. larvae genotypes ERIC I to IV, representatives of the bee gut microbiota, and a broad panel of members of the order Bacillales were analyzed for phage HB10c2-induced lysis. Breeding assays with infected bee larvae revealed that the in vitro phage activity observed was not predictive of the real-life scenario and therapeutic efficacy. On the basis of the disclosed P. larvae-bacteriophage coevolution, we discuss the future prospects of AFB phage therapy. Copyright © 2015, American Society for Microbiology. All Rights Reserved.


July 7, 2019

Whole-genome mapping as a novel high-resolution typing tool for Legionella pneumophila.

Legionella is the causative agent for Legionnaires’ disease (LD) and is responsible for several large outbreaks in the world. More than 90% of LD cases are caused by Legionella pneumophila, and studies on the origin and transmission routes of this pathogen rely on adequate molecular characterization of isolates. Current typing of L. pneumophila mainly depends on sequence-based typing (SBT). However, studies have shown that in some outbreak situations, SBT does not have sufficient discriminatory power to distinguish between related and nonrelated L. pneumophila isolates. In this study, we used a novel high-resolution typing technique, called whole-genome mapping (WGM), to differentiate between epidemiologically related and nonrelated L. pneumophila isolates. Assessment of the method by various validation experiments showed highly reproducible results, and WGM was able to confirm two well-documented Dutch L. pneumophila outbreaks. Comparison of whole-genome maps of the two outbreaks together with WGMs of epidemiologically nonrelated L. pneumophila isolates showed major differences between the maps, and WGM yielded a higher discriminatory power than SBT. In conclusion, WGM can be a valuable alternative to perform outbreak investigations of L. pneumophila in real time since the turnaround time from culture to comparison of the L. pneumophila maps is less than 24 h. Copyright © 2015, American Society for Microbiology. All Rights Reserved.


July 7, 2019

Emergence of Serotype IV group B Streptococcus adult invasive disease in Manitoba and Saskatchewan, Canada, is driven by colonal sequence type 459 strains.

Serotype IV group B Streptococcus (GBS) is emerging in Canada and the United States with rates as high as 5% of the total burden of adult invasive GBS disease. To understand this emergence, we studied the population structure and assessed the antimicrobial susceptibility of serotype IV isolates causing adult invasive infection in Manitoba and Saskatchewan, Canada, between 2010 and 2014. Whole-genome sequencing was used to determine multilocus sequence typing information and identify genes encoding antimicrobial resistance in 85 invasive serotype IV GBS strains. Antimicrobial susceptibility testing was performed by standard methods. Strain divergence was assessed using genome-wide single-nucleotide polymorphism analysis. Serotype IV strains were responsible for 16.9% of adult invasive GBS infections in Manitoba and Saskatchewan during the period. The majority of serotype IV isolates (89%) were clonally related, tetracycline-, erythromycin-, and clindamycin-resistant sequence type 459 (ST459) strains that possessed genes tetM and ermTR. Genome comparisons between ST459 and serotype V ST1 GBS identified several areas of recombination in an overall similar genomic background. Serotype IV ST459 GBS strains are expanding and causing a substantial percentage of adult invasive GBS disease. This emergence may be linked to the acquisition of resistance to tetracycline, macrolides, and lincosamides. Copyright © 2015, American Society for Microbiology. All Rights Reserved.


July 7, 2019

Complete chloroplast genome sequence of MD-2 pineapple and its comparative analysis among nine other plants from the subclass Commelinidae.

Pineapple (Ananas comosus var. comosus) is known as the king of fruits for its crown and is the third most important tropical fruit after banana and citrus. The plant, which is indigenous to South America, is the most important species in the Bromeliaceae family and is largely traded for fresh fruit consumption. Here, we report the complete chloroplast sequence of the MD-2 pineapple that was sequenced using the PacBio sequencing technology.In this study, the high error rate of PacBio long sequence reads of A. comosus’s total genomic DNA were improved by leveraging on the high accuracy but short Illumina reads for error-correction via the latest error correction module from Novocraft. Error corrected long PacBio reads were assembled by using a single tool to produce a contig representing the pineapple chloroplast genome. The genome of 159,636 bp in length is featured with the conserved quadripartite structure of chloroplast containing a large single copy region (LSC) with a size of 87,482 bp, a small single copy region (SSC) with a size of 18,622 bp and two inverted repeat regions (IRA and IRB) each with the size of 26,766 bp. Overall, the genome contained 117 unique coding regions and 30 were repeated in the IR region with its genes contents, structure and arrangement similar to its sister taxon, Typha latifolia. A total of 35 repeats structure were detected in both the coding and non-coding regions with a majority being tandem repeats. In addition, 205 SSRs were detected in the genome with six protein-coding genes contained more than two SSRs. Comparative chloroplast genomes from the subclass Commelinidae revealed a conservative protein coding gene albeit located in a highly divergence region. Analysis of selection pressure on protein-coding genes using Ka/Ks ratio showed significant positive selection exerted on the rps7 gene of the pineapple chloroplast with P less than 0.05. Phylogenetic analysis confirmed the recent taxonomical relation among the member of commelinids which support the monophyly relationship between Arecales and Dasypogonaceae and between Zingiberales to the Poales, which includes the A. comosus.The complete sequence of the chloroplast of pineapple provides insights to the divergence of genic chloroplast sequences from the members of the subclass Commelinidae. The complete pineapple chloroplast will serve as a reference for in-depth taxonomical studies in the Bromeliaceae family when more species under the family are sequenced in the future. The genetic sequence information will also make feasible other molecular applications of the pineapple chloroplast for plant genetic improvement.


July 7, 2019

An integrated map of structural variation in 2,504 human genomes.

Structural variants are implicated in numerous diseases and make up the majority of varying nucleotides among human genomes. Here we describe an integrated set of eight structural variant classes comprising both balanced and unbalanced variants, which we constructed using short-read DNA sequencing data and statistically phased onto haplotype blocks in 26 human populations. Analysing this set, we identify numerous gene-intersecting structural variants exhibiting population stratification and describe naturally occurring homozygous gene knockouts that suggest the dispensability of a variety of human genes. We demonstrate that structural variants are enriched on haplotypes identified by genome-wide association studies and exhibit enrichment for expression quantitative trait loci. Additionally, we uncover appreciable levels of structural variant complexity at different scales, including genic loci subject to clusters of repeated rearrangement and complex structural variants with multiple breakpoints likely to have formed through individual mutational events. Our catalogue will enhance future studies into structural variant demography, functional impact and disease association.


July 7, 2019

CHOgenome.org 2.0: Genome resources and website updates.

Chinese hamster ovary (CHO) cells are a major host cell line for the production of therapeutic proteins, and CHO cell and Chinese hamster (CH) genomes have recently been sequenced using next-generation sequencing methods. CHOgenome.org was launched in 2011 (version 1.0) to serve as a database repository and to provide bioinformatics tools for the CHO community. CHOgenome.org (version 1.0) maintained GenBank CHO-K1 genome data, identified CHO-omics literature, and provided a CHO-specific BLAST service. Recent major updates to CHOgenome.org (version 2.0) include new sequence and annotation databases for both CHO and CH genomes, a more user-friendly website, and new research tools, including a proteome browser and a genome viewer. CHO cell-line specific sequences and annotations facilitate cell line development opportunities, several of which are discussed. Moving forward, CHOgenome.org will host the increasing amount of CHO-omics data and continue to make useful bioinformatics tools available to the CHO community. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


July 7, 2019

Methicillin-susceptible, vancomycin-resistant Staphylococcus aureus, Brazil.

We report characterization of a methicillin-susceptible, vancomycin-resistant bloodstream isolate of Staphylococcus aureus recovered from a patient in Brazil. Emergence of vancomycin resistance in methicillin-susceptible S. aureus would indicate that this resistance trait might be poised to disseminate more rapidly among S. aureus and represents a major public health threat.


July 7, 2019

First detection of Klebsiella variicola producing OXA-181 carbapenemase in fresh vegetable imported from Asia to Switzerland.

The emergence and worldwide spread of carbapenemase-producing Enterobacteriaceae is of great concern to public health services. The aim of this study was to investigate the occurrence of carbapenemase-producing Enterobacteriaceae in fresh vegetables and spices imported from Asia to Switzerland.Twenty-two different fresh vegetable samples were purchased in March 2015 from different retail shops specializing in Asian food. The vegetables included basil leaves, bergamont leaves, coriander, curry leaves, eggplant and okra (marrow). Samples had been imported from Thailand, the Socialist Republic of Vietnam and India. After an initial enrichment-step, carbapenemase-producing Enterobacteriaceae were isolated from two carbapenem-containing selective media (SUPERCARBA II and Brilliance CRE Agar). Isolates were screened by PCR for the presence of bla KPC, bla NDM, bla OXA-48-like and bla VIM. An OXA-181-producing Klebsiella variicola was isolated in a coriander sample with origin Thailand/Vietnam. The bla OXA-181 gene was encoded in a 14’027 bp region flanked by two IS26-like elements on a 51-kb IncX3-type plasmid.The results of this study suggest that the international production and trade of fresh vegetables constitute a possible route for the spread of carbapenemase-producing Enterobacteriaceae. The presence of carbapenemase-producing organisms in the food supply is alarming and an important food safety issue.


July 7, 2019

Population genomics reveals additive and replacing horizontal gene transfers in the emerging pathogen Dickeya solani.

Dickeya solani is an emerging pathogen that causes soft rot and blackleg diseases in several crops including Solanum tuberosum, but little is known about its genomic diversity and evolution.We combined Illumina and PacBio technologies to complete the genome sequence of D. solani strain 3337 that was used as a reference to compare with 19 other genomes (including that of the type strain IPO2222(T)) which were generated by Illumina technology. This population genomic analysis highlighted an unexpected variability among D. solani isolates since it led to the characterization of two distinct sub-groups within the D. solani species. This approach also revealed different types of variations such as scattered SNP/InDel variations as well as replacing and additive horizontal gene transfers (HGT). Infra-species (between the two D. solani sub-groups) and inter-species (between D. solani and D. dianthicola) replacing HGTs were observed. Finally, this work pointed that genetic and functional variation in the motility trait could contribute to aggressiveness variability in D. solani.This work revealed that D. solani genomic variability may be caused by SNPs/InDels as well as replacing and additive HGT events, including plasmid acquisition; hence the D. solani genomes are more dynamic than that were previously proposed. This work alerts on precautions in molecular diagnosis of this emerging pathogen.


July 7, 2019

High quality draft genomes of the Mycoplasma mycoides subsp. mycoides challenge strains Afadé and B237.

Members of the Mycoplasma mycoides cluster’ represent important livestock pathogens worldwide. Mycoplasma mycoides subsp. mycoides is the etiologic agent of contagious bovine pleuropneumonia (CBPP), which is still endemic in many parts of Africa. We report the genome sequences and annotation of two frequently used challenge strains of Mycoplasma mycoides subsp. mycoides, Afadé and B237. The information provided will enable downstream ‘omics’ applications such as proteomics, transcriptomics and reverse vaccinology approaches. Despite the absence of Mycoplasma pneumoniae like cyto-adhesion encoding genes, the two strains showed the presence of protrusions. This phenotype is likely encoded by another set of genes.


July 7, 2019

Bordetella pertussis evolution in the (functional) genomics era.

The incidence of whooping cough caused by Bordetella pertussis in many developed countries has risen dramatically in recent years. This has been linked to the use of an acellular pertussis vaccine. In addition, it is thought that B. pertussis is adapting under acellular vaccine mediated immune selection pressure, towards vaccine escape. Genomics-based approaches have revolutionized the ability to resolve the fine structure of the global B. pertussis population and its evolution during the era of vaccination. Here, we discuss the current picture of B. pertussis evolution and diversity in the light of the current resurgence, highlight import questions raised by recent studies in this area and discuss the role that functional genomics can play in addressing current knowledge gaps.© FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.


July 7, 2019

Twenty years of bacterial genome sequencing.

Twenty years ago, the publication of the first bacterial genome sequence, from Haemophilus influenzae, shook the world of bacteriology. In this Timeline, we review the first two decades of bacterial genome sequencing, which have been marked by three revolutions: whole-genome shotgun sequencing, high-throughput sequencing and single-molecule long-read sequencing. We summarize the social history of sequencing and its impact on our understanding of the biology, diversity and evolution of bacteria, while also highlighting spin-offs and translational impact in the clinic. We look forward to a ‘sequencing singularity’, where sequencing becomes the method of choice for as-yet unthinkable applications in bacteriology and beyond.


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