scholarly journals PPalign: Optimal alignment of Potts models representing proteins with direct coupling information

2020 ◽  
Author(s):  
Hugo Talibart ◽  
François Coste
Keyword(s):  
Markov Models ◽  
Pairwise Alignment ◽  
Homology Search ◽  
Sequence Alignments ◽  
Potts Models ◽  
Functional Annotations ◽  
Current State ◽  
Linear Programming Formulation ◽  
Computational Bottleneck ◽  
New Research

AbstractBackgroundTo assign structural and functional annotations to the ever increasing amount of sequenced proteins, the main approach relies on sequence-based homology search methods, e.g. BLAST or the current state-of-the-art methods based on profile Hidden Markov Models (pHMM), which rely on significant alignments of query sequences to annotated proteins or protein families. While powerful, these approaches do not take coevolution between residues into account. Taking advantage of recent advances in the field of contact prediction, we propose here to represent proteins by Potts models, which model direct couplings between positions in addition to positional composition, and to compare proteins by aligning these models. Due to non-local dependencies, the problem of aligning Potts models is hard and remains the main computational bottleneck for their use.ResultsWe introduce here an Integer Linear Programming formulation of the problem and PPalign, a program based on this formulation, to compute the optimal pairwise alignment of Potts models representing proteins in tractable time. The approach is assessed with respect to a non-redundant set of reference pairwise sequence alignments from SISYPHUS benchmark which have lowest sequence identity (between 3% and 20%) and enable to build reliable Potts models for each sequence to be aligned. This experimentation confirms that Potts models can be aligned in reasonable time (1′37″ in average on these alignments). The contribution of couplings is evaluated in comparison with HHalign and PPalign without couplings. Although Potts models were not fully optimized for alignment purposes and simple gap scores were used, PPalign yields a better mean F1 score and finds significantly better alignments than HHalign and PPalign without couplings in some cases.ConclusionsThese results show that pairwise couplings from protein Potts models can be used to improve the alignment of remotely related protein sequences in tractable time. Our experimentation suggests yet that new research on the inference of Potts models is now needed to make them more comparable and suitable for homology search. We think that PPalign’s guaranteed optimality will be a powerful asset to perform unbiased investigations in this direction.

scholarly journals Comparative comprehensive analysis on natural infections of Hymenolepis diminuta and Hymenolepis nana in commensal rodents

2021 ◽  
Vol 58 (3) ◽  
pp. 248-262
Author(s):  
S. K. Brar ◽  
N. Singla ◽  
L. D. Singla
Keyword(s):  
Mononuclear Cells ◽  
Rattus Rattus ◽  
Pairwise Alignment ◽  
Hymenolepis Diminuta ◽  
Female Rats ◽  
Intestinal Lumen ◽  
Molecular Characterisation ◽  
Hymenolepis Nana ◽  
Male And Female Rats ◽  
Nuclear Its

Summary This first comprehensive report from Punjab province of India relates to patho-physiological alterations alongwith morpho-molecular characterisation and risk assessment of natural infections of Hymenolepis diminuta and Hymenolepis nana in 291commensal rodents including house rat, Rattus rattus (n=201) and lesser bandicoot rat, Bandicota bangalensis (n=90). Small intestine of 53.61 and 64.95 % rats was found infected with H. diminuta and H. nana, respectively with a concurrent infection rate of 50.86 %. There was no association between male and female rats and H. diminuta and H. nana infections (ᵡ2 = 0.016 and 0.08, respectively, d.f.= 1, P>0.05), while the host age had significant effect on prevalence of H. diminuta and H. nana (ᵡ2 = 28.12 and 7.18, respectively, d.f.= 1, P≤0.05) infection. Examination of faecal samples and intestinal contents revealed globular shaped eggs of H. diminuta without polar filaments (76.50 ± 3.01μm x 67.62 ± 2.42 μm), while smaller sized oval eggs of H. nana were with 4 – 8 polar filaments (47.87 ± 1.95 μm x 36.12 ± 3.05 μm). Cestode infection caused enteritis, sloughing of intestinal mucosa, necrosis of villi and inflammatory reaction with infiltration of mononuclear cells in the mucosa and submucosa. Morphometric identification of the adult cestodes recovered from the intestinal lumen was confirmed by molecular characterisation based on nuclear ITS-2 loci which showed a single band of 269 bp and 242 bp for H. diminuta and H. nana, respectively. Pairwise alignment of the ITS-2 regions showed 99.46 % similarity with sequences of H. diminuta from USA and 100 % similarity with sequences of H. nana from Slovakia, Kosice.

scholarly journals Analysis of Brachypodium genomes with genome-wide optical maps

Genome ◽  
2018 ◽  
Vol 61 (8) ◽  
pp. 559-565 ◽  
Author(s):  
Tingting Zhu ◽  
Zhaorong Hu ◽  
Juan C. Rodriguez ◽  
Karin R. Deal ◽  
Jan Dvorak ◽  
...  
Keyword(s):  
Genetic Model ◽  
Brachypodium Distachyon ◽  
Pairwise Alignment ◽  
Whole Genome ◽  
Structural Variants ◽  
Genome Wide ◽  
Complex Process ◽  
Optical Maps ◽  
Lines Of Evidence ◽  
Detection And Quantification

Brachypodium distachyon (n = 5) is a diploid and has been widely used as a genetic model. Brachypodium stacei (n = 10) and B. hybridum (n = 15) are species that are related to B. distachyon, leading to an hypothesis that they are part of a polyploid series based on x = 5. Several lines of evidence suggest that this hypothesis is incorrect and that the genomes of the three taxa may have evolved by a more complex process. We constructed an optical whole-genome BioNano genome (BNG) map for each species and did pairwise alignment of the BNG maps. The maps showed that B. distachyon and B. stacei are both diploid, in spite of B. stacei having twice as many chromosomes as B. distachyon, and that B. hybridum is an allopolyploid formed from hybridization between B. distachyon and B. stacei. This study also demonstrated the use of BNG maps in the detection and quantification of structural variants among the genomes.

Multiple Sequence Alignment Optimization Using Meta-Heuristic Techniques

2020 ◽  
pp. 565-579 ◽  
Author(s):  
Mohamed Issa ◽  
Aboul Ella Hassanien
Keyword(s):  
Sequence Alignment ◽  
Multiple Sequence Alignment ◽  
Phylogenetic Trees ◽  
Pairwise Alignment ◽  
Accurate Method ◽  
Alignment Algorithm ◽  
Bacterial Foraging Optimization ◽  
Multiple Sequence ◽  
Speed Up ◽  
Dna Fragment Assembly

Sequence alignment is a vital process in many biological applications such as Phylogenetic trees construction, DNA fragment assembly and structure/function prediction. Two kinds of alignment are pairwise alignment which align two sequences and Multiple Sequence alignment (MSA) that align sequences more than two. The accurate method of alignment is based on Dynamic Programming (DP) approach which suffering from increasing time exponentially with increasing the length and the number of the aligned sequences. Stochastic or meta-heuristics techniques speed up alignment algorithm but with near optimal alignment accuracy not as that of DP. Hence, This chapter aims to review the recent development of MSA using meta-heuristics algorithms. In addition, two recent techniques are focused in more deep: the first is Fragmented protein sequence alignment using two-layer particle swarm optimization (FTLPSO). The second is Multiple sequence alignment using multi-objective based bacterial foraging optimization algorithm (MO-BFO).

scholarly journals Comparative Molecular Description of a Novel GST Gene in Culex pipiens (Diptera: Culicidae)

2020 ◽  
Vol 57 (5) ◽  
pp. 1440-1446
Author(s):  
Hagar Samy Ali ◽  
Amany Soliman Khaled ◽  
Laila Sayed Hamouda ◽  
Enas Hamdy Ghallab
Keyword(s):  
Culex Pipiens ◽  
Direct Sequencing ◽  
Pairwise Alignment ◽  
Reference Sequence ◽  
Rflp Markers ◽  
Glutathione S Transferase ◽  
Disease Vector ◽  
Diagnostic Time ◽  
Susceptibility Status ◽  
Molecular Description

Abstract Repeated exposure to insecticides, particularly pyrethroids and organophosphates, has resulted in the development of insecticide resistance in the mosquito Culex pipiens, a primary disease vector. Glutathione S-transferase (GST) is involved in the phase II detoxification of numerous xenobiotics, including insecticides. In this study, a GST gene (CPIJ002678) was amplified, sequenced, and used in comprehensive molecular analyses ending up in development of a rapid assay to distinguish more tolerant individuals from susceptible Culex pipiens using the Restriction Fragment Length Polymorphism (RFLP) technique. Field collected Culex pipiens strains from untreated areas, organophosphates-treated areas and a lab strain reared for many generations, all were used in CDC bottle bioassays to evaluate the susceptibility status of the studied individuals to malathion insecticide. Interestingly, both field sites collected groups showed high levels of resistance at the malathion diagnostic time. Gene amplification, and bidirectional direct sequencing results were analyzed. Compared with the reference genome sequence, the pairwise alignment of the amplified sequences showed 96.6% similarity to the reference sequence in the GenBank database. The confirmed gene sequences were assembled and aligned using various bioinformatic softwares. The assembled contigs were used in NEBcutter V2.0 for constructing restriction maps and checked for the availability of differences (if present) between susceptible and more tolerant strains. Specific molecular RFLP markers were successfully recognized to differentiate the more tolerant from the susceptible Culex pipiens phenotypes.

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