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Schroeder, D.

Publications and source records attributed to Schroeder, D..

3 recordsLinked to original sources
bioRxiv2025

Evaluating the antiviral activity of Termin-8 and Finio against a surrogate ASFV-like algal virus

IntroductionAnitox has developed and markets Termin-8 (a formaldehyde-based product) and Finio (non-formaldehyde solution) for the control microbial contamination in feed. To date, both Finio and Termin-8 have not been tested for their potential antiviral activity against megaviruses, such African swine fever virus (ASFV) and its surrogate algal virus, Emiliania huxleyi virus (EhV). Given the limited access and great expense for routine chemical mitigation testing with ASFV, we focused on using EhV as a safe and effective surrogate to evaluate the antiviral activity of these Anitox products. The specific objective of the current study was to evaluate the time course of incubation from hours to days to mimic possible field relevant exposure times for the potential preventative mitigation of megaviruses using Termin-8 and Finio. MethodsEmiliania huxleyi virus was treated with the Anitox recommended concentrations of Termin-8 (0.1% to 0.3% final) and Finio (0.05% to 0.2% final) in biological triplicate experiments. Both viability qPCR (V-qPCR) and standard PCR (S-qPCR) were conducted for EhV copies at 1 hr, 5 hrs, 24 hrs and day 7 post-inoculation. ResultsWe observed that both Termin-8 and Finio, at their highest treatment concentrations, showed the greatest log reduction of 2 and 4.5 log10 units, respectively, at the earliest 1 hr post-inoculation time point. Although Termin-8 efficacy did not improve with time, treatment with Finio showed 100% viable viral inactivation (>5 log10 reduction units) at the lowest concentration after 7 days of exposure. In addition, Finio showed negligible viral DNA removal post-treatment as observed via S-qPCR, but use of Termin-8 resulted in a reduction of viral DNA (S-qPCR) equivalent to that observed using the V-qPCR assay. DiscussionOur results demonstrate for the first time that both Termin-8 and Finio can be used as effective chemical mitigants against megaviruses such as EhV and ASFV. Moreover, the mechanism of chemical mitigation involves degradation of the virus particle itself. However, although Termin-8 efficacy appeared to be less than that of Finio, this is likely not the case because Termin-8 cross-links protein viral capsids and fixes the viral particle to make it non-infectious. With the threat of ASFV introduction into the North American swine industry and other non-infected regions around the world, the use of both Termin-8 and Finio as an effective preventive or mitigation strategy to prevent the transmission of ASFV by reducing particle viability in contaminated feed. Additional research is warranted with ASFV, in the presence of various types of feed ingredients and complete feeds and use bioassays to evaluate infectivity because results from V-qPCR revealed that intact viable particles remain post-treatment.

molecular biology↗
bioRxiv2022

Vaccination decreases the risk of influenza A virus reassortment with a concomitant increase in subgenomic genetic variation in pigs

Although vaccination is broadly used in North American swine breeding herds, managing swine influenza is challenging primarily due to the continuous evolution of influenza A virus (IAV) and the ability of the virus to transmit among vaccinated pigs. Studies that have simultaneously assessed the impact of vaccination on the emergence of IAV reassortment and genetic variation in pigs are limited. Here we directly sequenced 28 bronchoalveolar lavage fluid (BALF) samples collected from vaccinated and unvaccinated pigs co-infected with H1N1 and H3N2 IAV strains, and characterized 202 individual viral plaques recovered from 13 BALF samples. We identified 54 reassortant viruses that were grouped in 16 distinct and 18 mixed genotypes. Notably, we found that prime-boost vaccinated pigs had less reassortant viruses than non-vaccinated pigs, likely due to a reduction in the number of days pigs were co-infected with both challenge viruses. However, direct sequencing from BALF samples revealed limited impact of vaccination on viral variant frequency, evolutionary rates, and nucleotide diversity in any IAV coding regions. Overall, our results highlight the value of IAV vaccination not only at limiting virus replication in pigs but also at protecting public health by restricting the generation of novel reassortants with zoonotic and/or pandemic potential.

microbiology↗
bioRxiv2019

A cost-efficient open source laser engine for microscopy

Scientific-grade lasers are costly components of modern microscopes. For high-power applications, such as single-molecule localization microscopy, their price can become prohibitive. Here, we present an open-source high-power laser engine that can be built for a fraction of the cost. It uses affordable, yet powerful laser diodes at wavelengths of 405 nm, 488 nm and 640 nm and optionally a 561 nm diode-pumped solid-state laser. The light is delivered to the microscope via an agitated multimode fiber in order to suppress speckles. We provide the part lists, CAD files and detailed descriptions, allowing any research group to build their own laser engine.

biophysics↗