scholarly journals De novo haplotype reconstruction in viral quasispecies using paired-end read guided path finding

2018 ◽  
Author(s):  
Jiao Chen ◽  
Yingchao Zhao ◽  
Yanni Sun
Keyword(s):  
Immune Responses ◽  
De Novo ◽  
Rna Virus ◽  
Haplotype Reconstruction ◽  
Viral Quasispecies ◽  
Host Immune Responses ◽  
Sequencing Technologies ◽  
Treatment And Prevention ◽  
Individual Host ◽  
Generation Sequencing

AbstractMotivationRNA virus populations contain closely related but different viral strains infecting an individual host. As the selection acts on clouds of mutants rather than single sequences, these viruses have abilities to escape host immune responses or develop drug resistance. Reconstruction of the viral haplotypes is a fundamental step to characterize the virus population, predict their viral phenotypes, and finally provide important information for clinical treatment and prevention. Advances of the next-generation sequencing technologies open up new opportunities to assemble full-length haplotypes. However, error-prone short reads, high similarity between related strains, unknown number of haplotypes pose computational challenges for reference-free haplotype reconstruction. There is still big room to improve the performance of existing haplotype assembly tools.ResultsIn this work, we developed a de novo haplotype reconstruction tool PEHaplo for viral quasispecies data, which contains a group of related but different viral strains. PEHaplo employs paired-end reads to distinguish highly similar strains. We applied it to both simulated and real quasispecies data, and the results were benchmarked against several recently published haplotype reconstruction tools. The comparison shows that PEHaplo outperforms the benchmarked tools in a comprehensive set of metrics.AvailabilityThe source code and the documentation of PEHaplo is available at https://github.com/chjiao/[email protected]

scholarly journals Porcine Reproductive and Respiratory Syndrome Virus: Immune Escape and Application of Reverse Genetics in Attenuated Live Vaccine Development

Vaccines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 480
Author(s):  
Honglei Wang ◽  
Yangyang Xu ◽  
Wenhai Feng
Keyword(s):  
Immune Responses ◽  
Reverse Genetics ◽  
Vaccine Development ◽  
Immune Escape ◽  
Rna Virus ◽  
Economic Losses ◽  
Respiratory Syndrome Virus ◽  
Live Vaccines ◽  
Host Immune Responses ◽  
Inactivated Vaccines

Porcine reproductive and respiratory syndrome virus (PRRSV), an RNA virus widely prevalent in pigs, results in significant economic losses worldwide. PRRSV can escape from the host immune response in several processes. Vaccines, including modified live vaccines and inactivated vaccines, are the best available countermeasures against PRRSV infection. However, challenges still exist as the vaccines are not able to induce broad protection. The reason lies in several facts, mainly the variability of PRRSV and the complexity of the interaction between PRRSV and host immune responses, and overcoming these obstacles will require more exploration. Many novel strategies have been proposed to construct more effective vaccines against this evolving and smart virus. In this review, we will describe the mechanisms of how PRRSV induces weak and delayed immune responses, the current vaccines of PRRSV, and the strategies to develop modified live vaccines using reverse genetics systems.

Computational Approaches for Transcriptome Assembly Based on Sequencing Technologies

2020 ◽  
Vol 15 (1) ◽  
pp. 2-16
Author(s):  
Yuwen Luo ◽  
Xingyu Liao ◽  
Fang-Xiang Wu ◽  
Jianxin Wang
Keyword(s):  
De Novo ◽  
Transcriptome Assembly ◽  
Critical Role ◽  
High Sensitivity ◽  
Biological Properties ◽  
Sequencing Data ◽  
Sequencing Technologies ◽  
Long Reads ◽  
Massive Sequencing ◽  
Generation Sequencing

Transcriptome assembly plays a critical role in studying biological properties and examining the expression levels of genomes in specific cells. It is also the basis of many downstream analyses. With the increase of speed and the decrease in cost, massive sequencing data continues to accumulate. A large number of assembly strategies based on different computational methods and experiments have been developed. How to efficiently perform transcriptome assembly with high sensitivity and accuracy becomes a key issue. In this work, the issues with transcriptome assembly are explored based on different sequencing technologies. Specifically, transcriptome assemblies with next-generation sequencing reads are divided into reference-based assemblies and de novo assemblies. The examples of different species are used to illustrate that long reads produced by the third-generation sequencing technologies can cover fulllength transcripts without assemblies. In addition, different transcriptome assemblies using the Hybrid-seq methods and other tools are also summarized. Finally, we discuss the future directions of transcriptome assemblies.

scholarly journals Telomere Length De Novo Assembly of all 7 Chromosomes and Mitogenome Sequencing of the Model Entomopathogenic Fungus, Metarhizium Brunneum, by Means of a Novel Assembly Pipeline

2020 ◽  
Author(s):  
Zack Saud ◽  
Alexandra M. Kortsinoglou ◽  
Vassili N. Kouvelis ◽  
Tariq M. Butt
Keyword(s):  
Entomopathogenic Fungus ◽  
De Novo ◽  
Gene Prediction ◽  
Fungal Species ◽  
Orthologous Protein ◽  
Metarhizium Brunneum ◽  
Sequencing Technologies ◽  
Protein Clusters ◽  
Assembly Pipeline ◽  
Generation Sequencing

Abstract More accurate and complete reference genomes have improved understanding of gene function, biology, and evolutionary mechanisms. Hybrid genome assembly approaches leverage benefits of both long, relatively error-prone reads from third-generation sequencing technologies and short, accurate reads from second-generation sequencing technologies, to produce more accurate and contiguous de novo genome assemblies in comparison to using either technology independently. In this study, we present a novel hybrid assembly pipeline that allowed for both mitogenome de novo assembly and telomere length de novo assembly of all 7 chromosomes of the model entomopathogenic fungus, Metarhizium brunneum. The improved assembly allowed for better ab initio gene prediction and a more BUSCO complete proteome set has been generated in comparison to the eight current NCBI reference Metarhizium spp. genomes. Remarkably, we note that including the mitogenome in ab initio gene prediction training improved overall gene prediction. The assembly was further validated by comparing contig assembly agreement across various assemblers, assessing the assembly performance of each tool. Genomic synteny and orthologous protein clusters were compared between Metarhizium brunneum and three other Hypocreales species with complete genomes, identifying core proteins, and listing orthologous protein clusters shared uniquely between the two entomopathogenic fungal species, so as to further facilitate the understanding of molecular mechanisms underpinning fungal-insect pathogenesis. The novel assembly pipeline may be used for other haploid fungal species, facilitating the need to produce high-quality reference fungal genomes, leading to better understanding of fungal genomic evolution, chromosome structuring and gene regulation.

scholarly journals Accuracy of microbial community diversity estimated by closed- and open-reference OTUs

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3889 ◽  
Author(s):  
Robert C. Edgar
Keyword(s):  
Ribosomal Rna ◽  
De Novo ◽  
Community Diversity ◽  
Reference Database ◽  
Mock Community ◽  
Variable Regions ◽  
Operational Taxonomic Units ◽  
Sequencing Technologies ◽  
Generation Sequencing ◽  
Mock Communities

Next-generation sequencing of 16S ribosomal RNA is widely used to survey microbial communities. Sequences are typically assigned to Operational Taxonomic Units (OTUs). Closed- and open-reference OTU assignment matches reads to a reference database at 97% identity (closed), then clusters unmatched reads using a de novo method (open). Implementations of these methods in the QIIME package were tested on several mock community datasets with 20 strains using different sequencing technologies and primers. Richness (number of reported OTUs) was often greatly exaggerated, with hundreds or thousands of OTUs generated on Illumina datasets. Between-sample diversity was also found to be highly exaggerated in many cases, with weighted Jaccard distances between identical mock samples often close to one, indicating very low similarity. Non-overlapping hyper-variable regions in 70% of species were assigned to different OTUs. On mock communities with Illumina V4 reads, 56% to 88% of predicted genus names were false positives. Biological inferences obtained using these methods are therefore not reliable.

scholarly journals A beginner’s guide for FMDV quasispecies analysis: sub-consensus variant detection and haplotype reconstruction using next-generation sequencing

2019 ◽  
Vol 21 (5) ◽  
pp. 1766-1775 ◽  
Author(s):  
Marco Cacciabue ◽  
Anabella Currá ◽  
Elisa Carrillo ◽  
Guido König ◽  
María Inés Gismondi
Keyword(s):  
Next Generation Sequencing ◽  
Rna Virus ◽  
Foot And Mouth Disease ◽  
Next Generation Sequencing Data ◽  
Complete Analysis ◽  
Viral Quasispecies ◽  
Next Generation ◽  
Sequencing Data ◽  
Viral Genomes ◽  
Generation Sequencing

Abstract Deep sequencing of viral genomes is a powerful tool to study RNA virus complexity. However, the analysis of next-generation sequencing data might be challenging for researchers who have never approached the study of viral quasispecies by this methodology. In this work we present a suitable and affordable guide to explore the sub-consensus variability and to reconstruct viral quasispecies from Illumina sequencing data. The guide includes a complete analysis pipeline along with user-friendly descriptions of software and file formats. In addition, we assessed the feasibility of the workflow proposed by analyzing a set of foot-and-mouth disease viruses (FMDV) with different degrees of variability. This guide introduces the analysis of quasispecies of FMDV and other viruses through this kind of approach.

Optimality analysis of Th1/Th2 immune responses during microparasite-macroparasite co-infection, with epidemiological feedbacks

Parasitology ◽  
2008 ◽  
Vol 135 (7) ◽  
pp. 841-853 ◽  
Author(s):  
ANDY FENTON ◽  
TRACEY LAMB ◽  
ANDREA L. GRAHAM
Keyword(s):  
Immune Responses ◽  
Population Level ◽  
Parasite Abundance ◽  
Individual Level ◽  
Host Immune Responses ◽  
Individual Host ◽  
Diverse Community ◽  
The Individual ◽  
Optimality Models

SUMMARYIndividuals are typically co-infected by a diverse community of microparasites (e.g. viruses or protozoa) and macroparasites (e.g. helminths). Vertebrates respond to these parasites differently, typically mounting T helper type 1 (Th1) responses against microparasites and Th2 responses against macroparasites. These two responses may be antagonistic such that hosts face a ‘decision’ of how to allocate potentially limiting resources. Such decisions at the individual host level will influence parasite abundance at the population level which, in turn, will feed back upon the individual level. We take a first step towards a complete theoretical framework by placing an analysis of optimal immune responses under microparasite-macroparasite co-infection within an epidemiological framework. We show that the optimal immune allocation is quantitatively sensitive to the shape of the trade-off curve and qualitatively sensitive to life-history traits of the host, microparasite and macroparasite. This model represents an important first step in placing optimality models of the immune response to co-infection into an epidemiological framework. Ultimately, however, a more complete framework is needed to bring together the optimal strategy at the individual level and the population-level consequences of those responses, before we can truly understand the evolution of host immune responses under parasite co-infection.

scholarly journals HAPHPIPE: Haplotype Reconstruction and Phylodynamics for Deep Sequencing of Intra-Host Viral Populations

2020 ◽  
Author(s):  
Matthew L Bendall ◽  
Keylie M Gibson ◽  
Margaret C Steiner ◽  
Uzma Rentia ◽  
Marcos Pérez-Losada ◽  
...  
Keyword(s):  
Deep Sequencing ◽  
De Novo ◽  
Consensus Sequence ◽  
Haplotype Reconstruction ◽  
Consensus Sequences ◽  
Genome Wide ◽  
Genomic Regions ◽  
Next Generation Sequencing Ngs ◽  
Ngs Data ◽  
Generation Sequencing

Abstract Deep sequencing of viral populations using next generation sequencing (NGS) offers opportunities to understand and investigate evolution, transmission dynamics, and population genetics. Currently, the standard practice for processing NGS data to study viral populations is to summarize all the observed sequences from a sample as a single consensus sequence, thus discarding valuable information about the intra-host viral molecular epidemiology. Furthermore, existing analytical pipelines may only analyze genomic regions involved in drug resistance, thus are not suited for full viral genome analysis. Here we present HAPHPIPE, a HAplotype and PHylodynamics PIPEline for genome-wide assembly of viral consensus sequences and haplotypes. The HAPHPIPE protocol includes modules for quality trimming, error correction, de novo assembly, alignment, and haplotype reconstruction. The resulting consensus sequences, haplotypes, and alignments can be further analyzed using a variety of phylogenetic and population genetic software. HAPHPIPE is designed to provide users with a single pipeline to rapidly analyze sequences from viral populations generated from NGS platforms and provide quality output properly formatted for downstream evolutionary analyses.

scholarly journals Telomere length de novo assembly of all 7 chromosomes and mitogenome sequencing of the model entomopathogenic fungus, Metarhizium brunneum, by means of a novel assembly pipeline

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Zack Saud ◽  
Alexandra M. Kortsinoglou ◽  
Vassili N. Kouvelis ◽  
Tariq M. Butt
Keyword(s):  
De Novo Assembly ◽  
De Novo ◽  
Gene Prediction ◽  
Fungal Species ◽  
Orthologous Protein ◽  
Metarhizium Brunneum ◽  
Sequencing Technologies ◽  
Protein Clusters ◽  
Assembly Pipeline ◽  
Generation Sequencing

Abstract Background More accurate and complete reference genomes have improved understanding of gene function, biology, and evolutionary mechanisms. Hybrid genome assembly approaches leverage benefits of both long, relatively error-prone reads from third-generation sequencing technologies and short, accurate reads from second-generation sequencing technologies, to produce more accurate and contiguous de novo genome assemblies in comparison to using either technology independently. In this study, we present a novel hybrid assembly pipeline that allowed for both mitogenome de novo assembly and telomere length de novo assembly of all 7 chromosomes of the model entomopathogenic fungus, Metarhizium brunneum. Results The improved assembly allowed for better ab initio gene prediction and a more BUSCO complete proteome set has been generated in comparison to the eight current NCBI reference Metarhizium spp. genomes. Remarkably, we note that including the mitogenome in ab initio gene prediction training improved overall gene prediction. The assembly was further validated by comparing contig assembly agreement across various assemblers, assessing the assembly performance of each tool. Genomic synteny and orthologous protein clusters were compared between Metarhizium brunneum and three other Hypocreales species with complete genomes, identifying core proteins, and listing orthologous protein clusters shared uniquely between the two entomopathogenic fungal species, so as to further facilitate the understanding of molecular mechanisms underpinning fungal-insect pathogenesis. Conclusions The novel assembly pipeline may be used for other haploid fungal species, facilitating the need to produce high-quality reference fungal genomes, leading to better understanding of fungal genomic evolution, chromosome structuring and gene regulation.

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