Sharif Digital Repository

Background: Current development of sequencing technologies is towards generating longer and noisier reads. Evidently, accurate alignment of these reads play an important role in any downstream analysis. Similarly, reducing the overall cost of sequencing is related to the time consumption of the aligner. The tradeoff between accuracy and speed is the main challenge in designing long read aligners. Results: We propose Meta-aligner which aligns long and very long reads to the reference genome very efficiently and accurately. Meta-aligner incorporates available short/long aligners as subcomponents and uses statistics from the reference genome to increase the performance. Meta-aligner estimates... 

Motif discovery is a challenging problem in molecular biology and has been attracting researcher's attention for years. Different kind of data and computational methods have been used to unravel this problem, but there is still room for improvement. In this study, our goal was to develop a method with the ability to identify all the TFBS signals, including known and unknown, inside the input set of sequences. We developed a clustering method specialized as part of our algorithm which outperforms other existing clustering methods such as DNACLUST and CD-HIT-EST in clustering short sequences. A scoring system was needed to determine how much a cluster is close to being a real motif. Multiple... 

Breast Cancer (BRCA) is the most common threat in women worldwide. Increasing death rate of diagnosed cases is the main leading cause of designing specific genosensors for BRCA − related cancer detection. In the present study, an ultrasensitive label − free electrochemical DNA (E − DNA) sensor based on conducting polymer/reduced graphene − oxide platform has been developed for the detection of BRCA1 gene. An electrochemical method was applied as a simple and controllable technique for the electrochemical reduction of graphene oxide and also, electro − polymerization of pyrrole − 3 − carboxylic acid monomer. The results of the present work show that the polymer − coated reduced graphene −... 

An impedimetric human papilloma virus (HPV) DNA biosensor based on gold nanotubes (AuNTs) in label free detection was materialized. The AuNTs decorated nanoporous polycarbonate (AuNTs-PC) template as biosensor electrode was fabricated by electrodeposition method. The single strand DNA (ss-DNA) probe was covalently immobilized onto the AuNTs-PC electrode. The hybridization of target sequences with the ss-DNA probe was observed by the electrochemical impedance spectroscopy (EIS). The biosensor showed high selectivity and could differentiate between the complementary, mismatch and non-complementary DNA sequences. The EIS measurements were matched to Randle's equivalent circuit. The... 

Background: Long reads provide valuable information regarding the sequence composition of genomes. Long reads are usually very noisy which renders their alignments on the reference genome a daunting task. It may take days to process datasets enough to sequence a human genome on a single node. Hence, it is of primary importance to have an aligner which can operate on distributed clusters of computers with high performance in accuracy and speed. Results: In this paper, we presented IMOS, an aligner for mapping noisy long reads to the reference genome. It can be used on a single node as well as on distributed nodes. In its single-node mode, IMOS is an Improved version of Meta-aligner (IM)... 

Background: Once aligned, long-reads can be a useful source of information to identify the type and position of structural variations. However, due to the high sequencing error of long reads, long-read structural variation detection methods are far from precise in low-coverage cases. To be accurate, they need to use high-coverage data, which in turn, results in an extremely time-consuming pipeline, especially in the alignment phase. Therefore, it is of utmost importance to have a structural variation calling pipeline which is both fast and precise for low-coverage data. Results: In this paper, we present SVNN, a fast yet accurate, structural variation calling pipeline for PacBio long-reads... 

Background: Once aligned, long-reads can be a useful source of information to identify the type and position of structural variations. However, due to the high sequencing error of long reads, long-read structural variation detection methods are far from precise in low-coverage cases. To be accurate, they need to use high-coverage data, which in turn, results in an extremely time-consuming pipeline, especially in the alignment phase. Therefore, it is of utmost importance to have a structural variation calling pipeline which is both fast and precise for low-coverage data. Results: In this paper, we present SVNN, a fast yet accurate, structural variation calling pipeline for PacBio long-reads... 

In this paper the field-effect transistor DNA biosensor for detecting hepatitis B virus (HBV) based on indium tin oxide nanowires (ITO NWs) in label free approach has been fabricated. Because of ITO nanowires intensive conductance and functional modified surface, the probe immobilization and target hybridization were increased strongly. The high resolution transmission electron microscopy (HRTEM) measurement showed that ITO nanowires were crystalline and less than 50 nm in diameter. The single-stranded hepatitis B virus DNA (SS-DNA) was immobilized as probe on the Au-modified nanowires. The DNA targets were measured in a linear concentration range from 1fM to 10 µM. The detection limit of... 

Aims: Our goal was the characterization of a new moderate thermophilic polycyclic aromatic hydrocarbon (PAH)-utilizing Nocardia strain. Methods and Results: A thermophilic bacterium, strain TSH1, was isolated from a contaminated soil. The macroscopic and microscopic features fit well with the description of Nocardia species. The results of 16S rRNA gene analysis showed 100% match to the type strain of N. otitidiscaviarum DSM 43242T. Strain TSH1 showed the same mycolic acid pattern as the type strain of N. otitidiscaviarum but its fatty acid profile did not permit identification to the species level. The carbon utilization profile of strain TSH1 was different from N. otitidiscaviarum. The... 

Background: Flagellin of Salmonella enterica serovar Enteritidis (SEF) stimulates immune responses to both itself and coapplied antigens. It is therefore used in vaccine development and immunotherapy. Removal of pathogenic S. enterica ser. Enteritidis from SEF production process is advantageous due to the process safety improvement. The protein solubility analysis using SDS-PAGE indicated that 53.49% of SEF expressed in Escherichia coli formed inclusion bodies. However, the protein recovery from inclusion bodies requires a complex process with a low yield. Objective: We thus aim to study possibility of enhancing SEF expression in E. coli in soluble form using chemical and molecular...