Last data update: Jan 27, 2025. (Total: 48650 publications since 2009)
Records 1-5 (of 5 Records) |
Query Trace: Becher J[original query] |
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Rapid detection of ricin at trace levels in complex matrices by asialofetuin-coated beads and bottom-up proteomics using high-resolution mass spectrometry
Piquet P , Saadi J , Fenaille F , Kalb SR , Becher F . Anal Bioanal Chem 2024 Ricin is a toxic protein regarded as a potential chemical weapon for bioterrorism or criminal use. In the event of a ricin incident, rapid analytical methods are essential for ricin confirmation in a diversity of matrices, from environmental to human or food samples. Mass spectrometry-based methods provide specific toxin identification but require prior enrichment by antibodies to reach trace-level detection in matrices. Here, we describe a novel assay using the glycoprotein asialofetuin as an alternative to antibodies for ricin enrichment, combined with the specific detection of signature peptides by high-resolution mass spectrometry. Additionally, optimizations made to the assay reduced the sample preparation time from 5 h to 80 min only. Method evaluation confirmed the detection of ricin at trace levels over a wide range of pH and in protein-rich samples, illustrating challenging matrices. This new method constitutes a relevant antibody-free solution for the fast and specific mass spectrometry detection of ricin in the situation of a suspected toxin incident, complementary to active ricin determination by adenine release assays. |
The epidemiology and costs of disease intervention specialist retention
Becher J , Salmon ME , Gift TL . Sex Transm Dis 2023 50 S64-S69 INTRODUCTION: The COVID-19 pandemic changed the environment in which disease intervention specialists (DIS) operate, as their skills were in demand beyond STD control programs. Workforce conditions generally have changed in the last 2 years, imposing additional challenges. Retaining STD DIS has become more difficult in the changed environment. MATERIALS AND METHODS: We conducted a landscape scan and obtained data from literature and personal observations to characterize current DIS workforce issues. We used published employment data to characterize current labor market conditions and described how cost-effectiveness analysis could be used to assess potential DIS retention interventions. An example illustrating cost-effectiveness concepts was developed. RESULTS: Many STD control programs faced difficulties in retaining STD DIS, because competing positions often could be done without field work. Economic and crime issues posed additional challenges. General workforce turnover has increased 33% since 2016. Turnover varies by age, gender, and education. Cost-effectiveness analysis can be used to assess DIS retention interventions, but data on costs and outcomes are needed on an ongoing basis. Changes in the workforce environment could impact both retention and the effectiveness of retention interventions. CONCLUSIONS: Workforce changes have impacted employee retention. Increased federal funding makes expansion of the DIS workforce possible, but the labor market environment will continue to pose challenges to recruitment and retention. |
The disulfide stress response and protein S-thioallylation caused by allicin and diallyl polysulfanes in Bacillus subtilis as revealed by transcriptomics and proteomics
Chi BK , Huyen NTT , Loi VV , Gruhlke MCH , Schaffer M , Mader U , Maass S , Becher D , Bernhardt J , Arbach M , Hamilton CJ , Slusarenko AJ , Antelmann H . Antioxidants (Basel) 2019 8 (12) Garlic plants (Allium sativum L.) produce antimicrobial compounds, such as diallyl thiosulfinate (allicin) and diallyl polysulfanes. Here, we investigated the transcriptome and protein S-thioallylomes under allicin and diallyl tetrasulfane (DAS4) exposure in the Gram-positive bacterium Bacillus subtilis. Allicin and DAS4 caused a similar thiol-specific oxidative stress response, protein and DNA damage as revealed by the induction of the OhrR, PerR, Spx, YodB, CatR, HypR, AdhR, HxlR, LexA, CymR, CtsR, and HrcA regulons in the transcriptome. At the proteome level, we identified, in total, 108 S-thioallylated proteins under allicin and/or DAS4 stress. The S-thioallylome includes enzymes involved in the biosynthesis of surfactin (SrfAA, SrfAB), amino acids (SerA, MetE, YxjG, YitJ, CysJ, GlnA, YwaA), nucleotides (PurB, PurC, PyrAB, GuaB), translation factors (EF-Tu, EF-Ts, EF-G), antioxidant enzymes (AhpC, MsrB), as well as redox-sensitive MarR/OhrR and DUF24-family regulators (OhrR, HypR, YodB, CatR). Growth phenotype analysis revealed that the low molecular weight thiol bacillithiol, as well as the OhrR, Spx, and HypR regulons, confer protection against allicin and DAS4 stress. Altogether, we show here that allicin and DAS4 cause a strong oxidative, disulfide and sulfur stress response in the transcriptome and widespread S-thioallylation of redox-sensitive proteins in B. subtilis. The results further reveal that allicin and polysulfanes have similar modes of actions and thiol-reactivities and modify a similar set of redox-sensitive proteins by S-thioallylation. |
Proposed BoNT/A and /B peptide substrates cannot detect multiple subtypes in the Endopep-MS Assay
Kalb SR , Baudys J , Kiernan K , Wang D , Becher F , Barr JR . J Anal Toxicol 2019 44 (2) 173-179 Botulinum neurotoxins (BoNTs) are a family of protein toxins consisting of seven known serotypes (BoNT/A-BoNT/G) and multiple subtypes within the serotypes, and all of which cause the disease botulism-a disease of great public health concern. Accurate detection of BoNTs in human clinical samples is therefore an important public health goal. To achieve this goal, our laboratory developed a mass spectrometry-based assay detecting the presence of BoNT via its enzymatic activity on a peptide substrate. Recently, publications reported the use of new peptide substrates to detect BoNT/A and /B with improved results over other peptide substrates. However, the authors did not provide results of their peptide substrate on multiple subtypes of BoNT. In this work, we describe the results of testing the new substrates with multiple BoNT/A and /B subtypes and find that the substrates cannot detect many subtypes of BoNT/A and /B. |
Recommended mass spectrometry-based strategies to identify ricin-containing samples
Kalb SR , Schieltz DM , Becher F , Astot C , Fredriksson SA , Barr JR . Toxins (Basel) 2015 7 (12) 4881-94 Ricin is a protein toxin produced by the castor bean plant (Ricinus communis) together with a related protein known as R. communis agglutinin (RCA120). Mass spectrometric (MS) assays have the capacity to unambiguously identify ricin and to detect ricin's activity in samples with complex matrices. These qualitative and quantitative assays enable detection and differentiation of ricin from the less toxic RCA120 through determination of the amino acid sequence of the protein in question, and active ricin can be monitored by MS as the release of adenine from the depurination of a nucleic acid substrate. In this work, we describe the application of MS-based methods to detect, differentiate and quantify ricin and RCA120 in nine blinded samples supplied as part of the EQuATox proficiency test. Overall, MS-based assays successfully identified all samples containing ricin or RCA120 with the exception of the sample spiked with the lowest concentration (0.414 ng/mL). In fact, mass spectrometry was the most successful method for differentiation of ricin and RCA120 based on amino acid determination. Mass spectrometric methods were also successful at ranking the functional activities of the samples, successfully yielding semi-quantitative results. These results indicate that MS-based assays are excellent techniques to detect, differentiate, and quantify ricin and RCA120 in complex matrices. |
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