Identification of Significant Pathogenic Nontuberculous Mycobacteria Species from Presumptive TB Patients Using Partial hsp65 Gene Sequencing

Purpose

To date, the diagnosis of nontuberculous mycobacteria (NTM) disease primarily relies on clinical symptoms and radiological features. Our objective was to apply a sequence-based analysis method by using partial gene sequencing of heat shock protein 65 (hsp65) to identify NTM species.

Patients and Methods

A total of 32 stored isolates obtained from individuals suspected of having pulmonary NTM infection were subjected to solid Ogawa culture. Genomic DNA from each sample was extracted and used in a conventional polymerase chain reaction (PCR) targeting a specific region of hsp65 gene. Identified amplicons from the PCR were then subjected to targeted sequencing. Analysis of the obtained hsp65 sequence was performed using DNA Baser tool. The consensus sequences obtained were compared to references in the GenBank NCBI database to determine NTM species.

Results

We identified several important NTM species which posses opportunistic characteristics. M. abscessus and M. chelonae are the most frequent NTM species identified in this study (40.63% and 18.75%, respectively). These two species have the potential to cause significant infections in human, ranging from opportunistic pulmonary infection to localized skin infection. Additionally, pathogenic NTM members of M. fortuitum group (MFG), M. avium, M. intracellulare, M. kansasii, and M. celatum were also found among all identified species.

Conclusion

Sequence-based analysis is a promising method for identifying species of NTM. The hsp65 gene has a high discriminatory power to identify opportunistic pathogen NTM species in specimens in Indonesia. Consequently, hsp65 partial gene sequencing is considerable as an alternative and reliable approach for NTM speciation.

The current and future role of sequence-based analysis in prostate cancer treatment

Prostate cancer is the most commonly diagnosed, nondermatologic malignancy in US men. Localized disease can be managed through active surveillance or curative, locally directed therapies, but 30% of men treated with surgery or radiation will need additional (often systemic) treatment for relapsed disease. While spectacular advances in medical treatment of advanced prostate cancer have improved the quality and duration of patients' lives, metastatic prostate cancer remains an incurable, lethal disease that requires additional therapies and better treatment strategies. The advent of ultra-high-throughput sequencing technology provides an opportunity to comprehensively assess the constellation of genetic and molecular events underlying each patient's tumor, and promises to enhance our ability to deliver specifically tailored personalized treatment to men with prostate cancer. The known biological and clinical heterogeneity of prostate cancer presents both opportunities and challenges to the application and utilization of sequence-based analysis to guide prostate cancer treatment.

Defining bacterial species in the genomic era: insights from the genus Acinetobacter

BACKGROUND

Microbial taxonomy remains a conservative discipline, relying on phenotypic information derived from growth in pure culture and techniques that are time-consuming and difficult to standardize, particularly when compared to the ease of modern high-throughput genome sequencing. Here, drawing on the genus Acinetobacter as a test case, we examine whether bacterial taxonomy could abandon phenotypic approaches and DNA-DNA hybridization and, instead, rely exclusively on analyses of genome sequence data.

RESULTS

In pursuit of this goal, we generated a set of thirteen new draft genome sequences, representing ten species, combined them with other publically available genome sequences and analyzed these 38 strains belonging to the genus. We found that analyses based on 16S rRNA gene sequences were not capable of delineating accepted species. However, a core genome phylogenetic tree proved consistent with the currently accepted taxonomy of the genus, while also identifying three misclassifications of strains in collections or databases. Among rapid distance-based methods, we found average-nucleotide identity (ANI) analyses delivered results consistent with traditional and phylogenetic classifications, whereas gene content based approaches appear to be too strongly influenced by the effects of horizontal gene transfer to agree with previously accepted species.

CONCLUSION

We believe a combination of core genome phylogenetic analysis and ANI provides an appropriate method for bacterial species delineation, whereby bacterial species are defined as monophyletic groups of isolates with genomes that exhibit at least 95% pair-wise ANI. The proposed method is backwards compatible; it provides a scalable and uniform approach that works for both culturable and non-culturable species; is faster and cheaper than traditional taxonomic methods; is easily replicable and transferable among research institutions; and lastly, falls in line with Darwin's vision of classification becoming, as far as is possible, genealogical.

Understanding Plant Cellulose Synthases through a Comprehensive Investigation of the Cellulose Synthase Family Sequences

The development of cellulose as an organizing structure in the plant cell wall was a key event in both the initial colonization and the subsequent domination of the terrestrial ecosystem by vascular plants. A wealth of experimental data has demonstrated the complicated genetic interactions required to form the large synthetic complex that synthesizes cellulose. However, these results are lacking an extensive analysis of the evolution, specialization, and regulation of the proteins that compose this complex. Here we perform an in-depth analysis of the sequences in the cellulose synthase (CesA) family. We investigate the phylogeny of the CesA family, with emphasis on evolutionary specialization. We define specialized clades and identify the class-specific regions within the CesA sequence that may explain this specialization. We investigate changes in regulation of CesAs by looking at the conservation of proposed phosphorylation sites. We investigate the conservation of sites where mutations have been documented that impair CesA function, and compare these sites to those observed in the closest cellulose synthase-like (Csl) families to better understand what regions may separate the CesAs from other Csls. Finally we identify two positions with strong conservation of the aromatic trait, but lacking conservation of amino acid identity, which may represent residues important for positioning the sugar substrate for catalysis. These analyses provide useful tools for understanding characterized mutations and post-translational modifications, and for informing further experiments to probe CesA assembly, regulation, and function through site-directed mutagenesis or domain swapping experiments.