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Biology subjects

Hoang, L. T.

Publications and source records attributed to Hoang, L. T..

3 recordsLinked to original sources

AutoPeptideML: Automated Machine Learning for Building Trustworthy Peptide Bioactivity Predictors

MotivationAutomated machine learning (AutoML) solutions can bridge the gap between new computational advances and their real-world applications by enabling experimental scientists to build their own custom models. We examine different steps in the development life-cycle of peptide bioactivity binary predictors and identify key steps where automation can not only result in a more accessible method, but also more robust and interpretable evaluation leading to more trustworthy models. ResultsWe present a new automated method for drawing negative peptides that achieves better balance between specificity and generalisation than current alternatives. We study the effect of homology-based partitioning for generating the training and testing data subsets and demonstrate that model performance is overestimated when no such homology correction is used, which indicates that prior studies may have overestimated their performance when applied to new peptide sequences. We also conduct a systematic analysis of different protein language models as peptide representation methods and find that they can serve as better descriptors than a naive alternative, but that there is no significant difference across models with different sizes or algorithms. Finally, we demonstrate that an ensemble of optimised traditional machine learning algorithms can compete with more complex neural network models, while being more computationally efficient. We integrate these findings into AutoPeptideML, an easy-to-use AutoML tool to allow researchers without a computational background to build new predictive models for peptide bioactivity in a matter of minutes. AvailabilitySource code, documentation, and data are available at https://github.com/IBM/AutoPeptideML and a dedicated webserver at http://peptide.ucd.ie/AutoPeptideML.

bioinformatics↗

Mixed Heavy Metals Stress Induces Global Iron Starvation as Revealed by System Level Multi-Omic Analyses

Globally, multiple heavy metal contamination is an increasingly common problem. As heavy metals have the potential to disrupt microbially-mediated biogeochemical cycling, it is critical to understand their impact on microbial physiology. However, systems-level studies on the effects of a combination of heavy metals on bacteria are lacking. Here, we use a native Bacillus cereus isolate from the subsurface of the Oak Ridge Reservation (ORR; Oak Ridge, TN, USA) -- representing a highly abundant species at the site-- to assess the combined impact of eight metal contaminants. Using this metal mixture and individual metals, all at concentrations based on the ORR site geochemistry, we performed growth experiments and proteomic analyses of the B. cereus strain, in combination with targeted MS-based metabolomics and gene expression profiling. The combination of eight metals impacts cell physiology in a manner that could not have been predicted from summing phenotypic responses to the individual metals. Specifically, exposure to the metal mixture elicited global iron starvation responses not observed in any of the individual metal treatments. As nitrate is also a significant contaminant at the ORR site and nitrate and nitrite reductases are iron-containing enzymes, we also examined the effects of the metal mixture on reduction of nitrogen oxides. We found that the metal mixture inhibits the activity of these enzymes through a combination of direct enzymatic damage and post-transcriptional and post-translational regulation. Altogether, these data suggest that metal mixture studies are critical for understanding how multiple rather than individual metals influence microbial processes in the environment.

microbiology↗

Exposing the Exposome with Global Metabolomics andCognitive Computing

Concurrent exposure to a wide variety of xenobiotics and their combined toxic effects can play a pivotal role in health and disease, yet are largely unexplored. Investigating the totality of these exposures, i.e. the exposome, and their specific biological effects constitutes a new paradigm for environmental health but still lacks high-throughput, user-friendly technology. We demonstrate the utility of mass spectrometry-based global exposure metabolomics combined with tailored database queries and cognitive computing for comprehensive exposure assessment and the straightforward elucidation of biological effects. The METLIN Exposome database has been redesigned to help identify environmental toxicants, food contaminants and supplements, drugs, and antibiotics as well as their biotransformation products, through its expansion with over 700,000 chemical structures to now include more than 950,000 unique small molecules. More importantly, we demonstrate how the XCMS/METLIN platform now allows for the readout of the biological effect of a toxicant through metabolomic-derived pathway analysis and further, cognitive computing provides a means of assessing the role of a potential toxicant. The presented workflow addresses many of the outstanding methodological challenges current exposome research is facing and will serve to gain a deeper understanding of the impact of environmental exposures and combinatory toxic effects on human health.

epidemiology↗