Variable region analysis of 16S rRNA gene sequences is the most common tool in bacterial taxonomic studies. Although used for distinguishing bacterial species, its use remains limited due to the presence of variable copy numbers with sequence variation in the genomes. In this study, 16S rRNA gene sequences, obtained from completely assembled whole genome and Sanger electrophoresis sequencing of cloned PCR products from Serratia fonticola GS2, were compared. Sanger sequencing produced a combination of sequences from multiple copies of 16S rRNA genes. To determine whether the variant copies of 16S rRNA genes affected Sanger sequencing, two ratios (5:5 and 8:2)…
We have recently shown that nanopore zero-mode waveguides are effective tools for capturing picogram levels of long DNA fragments for single-molecule DNA sequencing. Despite these key advantages, the manufacturing of large arrays is not practical due to the need for serial nanopore fabrication. To overcome this challenge, we have developed an approach for the wafer-scale fabrication of waveguide arrays on low-cost porous membranes, which are deposited using molecular-layer deposition. The membrane at each waveguide base contains a network of serpentine pores that allows for efficient electrophoretic DNA capture at picogram levels while eliminating the need for prohibitive serial pore milling.…
In the past several years, single-molecule sequencing platforms, such as those by Pacific Biosciences and Oxford Nanopore Technologies, have become available to researchers and are currently being tested for clinical applications. They offer exceptionally long reads that permit direct sequencing through regions of the genome inaccessible or difficult to analyze by short-read platforms. This includes disease-causing long repetitive elements, extreme GC content regions, and complex gene loci. Similarly, these platforms enable structural variation characterization at previously unparalleled resolution and direct detection of epigenetic marks in native DNA. Here, we review how these technologies are opening up new clinical avenues that…
Ethanol-type fermentation is one of three main fermentation types in the acidogenesis of anaerobic treatment systems. Non-spore-forming Ethanoligenens is as a typical genus capable of ethanol-type fermentation in mixed culture (i.e. acetate-ethanol fermentation). This genus can produce ethanol, acetate, CO2, and H2 using carbohydrates, and has application potential in anaerobic bioprocesses. Here, the complete genome sequences and methylome of Ethanoligenens harbinense strains with different autoaggregative and coaggregative abilities were obtained using the PacBio single-molecule real-time sequencing platform. The genome size of E. harbinense strains was about 2.97-3.10?Mb with 55.5% G+C content. 3020-3153 genes were annotated, most of which were methylated…
The ultimate goal for diploid genome determination is to completely decode homologous chromosomes independently, and several phasing programs from consensus sequences have been developed. These methods work well for lowly heterozygous genomes, but the manifold species have high heterozygosity. Additionally, there are highly divergent regions (HDRs), where the haplotype sequences differ considerably. Because HDRs are likely to direct various interesting biological phenomena, many genomic analysis targets fall within these regions. However, they cannot be accessed by existing phasing methods, and we have to adopt costly traditional methods. Here, we develop a de novo haplotype assembler, Platanus-allee ( http://platanus.bio.titech.ac.jp/platanus2 ), which…
Xanthomonas oryzae (Xo) are critical rice pathogens. Virulent lineages from Africa and Asia and less virulent strains from the US have been well characterized. X. campestris pv. leersiae (Xcl), first described in 1957, causes bacterial streak on the perennial grass, Leersia hexandra, and is a close relative of Xo. L. hexandra, a member of the Poaceae, is highly similar to rice phylogenetically, is globally ubiquitous around rice paddies, and is a reservoir of pathogenic Xo. We used long read, single molecule, real time (SMRT) genome sequences of five strains of Xcl from Burkina Faso, China, Mali and Uganda to determine…
The wide implementation of next-generation sequencing (NGS) technologies has revolutionized the field of medical genetics. However, the short read lengths of currently used sequencing approaches pose a limitation for identification of structural variants, sequencing repetitive regions, phasing alleles and distinguishing highly homologous genomic regions. These limitations may significantly contribute to the diagnostic gap in patients with genetic disorders who have undergone standard NGS, like whole exome or even genome sequencing. Now, the emerging long-read sequencing (LRS) technologies may offer improvements in the characterization of genetic variation and regions that are difficult to assess with the currently prevailing NGS approaches. LRS…