Publications by authors named "Justin L Williams"

3 Publications

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Mining Public Mass Spectrometry Data to Characterize the Diversity and Ubiquity of Specialized Metabolites.

Metabolites 2020 Nov 5;10(11). Epub 2020 Nov 5.

Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48823, USA.

is a ubiquitous environmental bacterium that causes chronic infections of burn wounds and in the lungs of cystic fibrosis (CF) patients. Vital to its infection is a myriad of specialized metabolites that serve a variety of biological roles including quorum sensing, metal chelation and inhibition of other competing bacteria. This study employed newly available algorithms for searching individual tandem mass (MS/MS) spectra against the publicly available Global Natural Product Social Molecular Networking (GNPS) database to identify the chemical diversity of these compounds and their presence in environmental, laboratory and clinical samples. For initial characterization, the metabolomes of eight clinical isolates of were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and uploaded to GNPS for spectral searching. Quinolones, rhamnolipids, phenazines and siderophores were identified and characterized; including the discovery of modified forms of the iron chelator pyochelin. Quinolones were highly diverse with the three base forms quinolone signal 2-heptyl-3-hydroxy-4()-quinolone (PQS), 4-heptyl-4()-quinolone (HHQ) and 2-heptyl-4-quinolone--oxide (HQNO) having extensive variation in the length of their acyl chain from as small as 3 carbons to as large as 17. Rhamnolipids were limited to either one or two sugars with a limited set of fatty acyl chains, but the base lipid form without the rhamnose was also detected. These specialized metabolites were identified from diverse sources including ant-fungal mutualist dens, soil, plants, human teeth, feces, various lung mucus samples and cultured laboratory isolates. Their prevalence in fecal samples was particularly notable as is not known as a common colonizer of the human gut. The chemical diversity of the compounds identified, particularly the quinolones, demonstrates a broad spectrum of chemical properties within these the metabolite groups with likely significant impacts on their biological functions. Mining public data with GNPS enables a new approach to characterize the chemical diversity of biological organisms, which includes enabling the discovery of new chemistry from pathogenic bacteria.
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http://dx.doi.org/10.3390/metabo10110445DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7694397PMC
November 2020

The Adolescent and Caregiver Sickle Cell Disease Self-management Skills Checklist: Preliminary Reliability and Validity.

J Pediatr Hematol Oncol 2020 01;42(1):12-19

Department of Psychology.

Adolescents with sickle cell disease (SCD) need assistance in developing the knowledge and skills that contribute to increased disease self-management and successful transition to adult-based health care. This study evaluated the preliminary psychometric properties of the Self-Management Skills Checklist (SMSC and SMSC-C; Adolescent and Caregiver versions), a measure of perceived SCD-specific knowledge and skills. A retrospective cohort study included 114 adolescents (mean=15.6 y) and their caregivers. We examined internal structure and reliability, score changes over time, and group differences. Cronbach coefficient alphas were 0.79 and 0.74 for caregiver-reported Skills and caregiver-reported knowledge, respectively, and 0.77 and 0.44 for adolescent-reported skills and adolescent-reported knowledge, respectively, indicating good internal consistency for 3 of the subscales. Poor reliability in the adolescent-reported knowledge summary score and factor analysis suggest an interpretation item-by-item, independent of one another. Participant group differences in age and chronic transfusion treatment existed in both summary and subscale scores of the SMSC and SMSC-C. Follow-up administrations of the scales indicated an increase in caregiver-reported skills for their adolescents from time 1 scores (M=3.72±0.83) to time 2 scores (M=3.99±0.63) (t16=2.178, P=0.045). Findings provide preliminary support for the usage of the SMSC and continued development to improve its psychometrics.
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http://dx.doi.org/10.1097/MPH.0000000000001618DOI Listing
January 2020

Diastereoselective synthesis of pyrrolidines using a nitrone/cyclopropane cycloaddition: synthesis of the tetracyclic core of nakadomarin A.

Org Lett 2005 Mar;7(5):953-5

Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7.

The synthesis of the tetracyclic core of nakadomarin A is described. The core contains all the heterocycles and the required stereocenters found in the natural product and provides a promising route to the target itself. The strategy utilizes a general, diastereoselective pyrrolidine synthesis that proceeds via a homo 3 + 2 dipolar cycloaddition. The scope of this methodology is also described. [structure: see text]
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http://dx.doi.org/10.1021/ol0501018DOI Listing
March 2005