Biology subjects

Borucki, M. K.

Publications and source records attributed to Borucki, M. K..

5 recordsLinked to original sources

bioRxiv2026

A Selenium-Deficient Mouse Model of Mouse-Adapted SARS-CoV-2 Demonstrates Variant Emergence Observed in SARS-CoV-2 Pandemic Variants

Host selenium deficiency has been shown to generate novel genetic variants in RNA viruses. With the predicted rise of selenium deficiency globally, we sought to determine if host selenium deficiency can be a predictive factor for RNA virus variant emergence. We utilized a selenium-deficient BALB/c mouse model to investigate how host selenium status influences the emergence of viral variants in mouse-adapted SARS-CoV-2. Mice were maintained on control or selenium-deficient diets and subjected to sequential rounds of diet-matched viral passage to generate diet-specific virus populations. Deep sequencing of passaged viral populations revealed that selenium-deficient passage drove a marked increase in inter-host genomic heterogeneity and produced a distinct mutational profile relative to control passage. Eighteen mutations were identified as unique to selenium-deficient passage, including variants previously observed during natural human SARS-CoV-2 evolution. These mutations were largely maintained at sub-consensus frequencies, indicating that selenium deficiency can expand the viral quasispecies landscape that enrichs reservoirs of adaptive potential. To determine how this altered mutant spectrum affected pathogenesis, we challenged normal diet-fed adult and aged BALB/c mice with control- or selenium-deficient-passaged virus. Although overt differences in weight loss, survival, and viral burden were generally modest, selenium-deficient-passaged virus induced pronounced increases in antiviral cytokine expression. Together, these findings identify host selenium deficiency as a driver of RNA virus population diversification and show that nutritionally stressed animal models can reproducibly generate mutations observed in nature.

microbiology↗

bioRxiv2024

Benchmarking concentration and direct extraction methods for wastewater-based surveillance of eight human respiratory viruses: implications for rapid application to novel pathogens

Wastewater monitoring is rapidly expanding to provide surveillance for a growing number of epidemic and endemic pathogens. To provide early warning and support rapid response to a novel virus through wastewater surveillance, it would be ideal to understand in advance which concentration and extraction methods are likely to be effective for dPCR-based methods, depending on virus characteristics. In this study, we spiked wastewater samples with eight human respiratory viruses and processed them with four commercial methods that concentrate and/or extract nucleic acids from both liquid and solid fractions (Promega, Nanotrap, InnovaPrep), or only the solid fraction of wastewater (Solids). Our findings provide encouraging evidence that all four concentration/extraction methods combined with dPCR could detect an emerging virus in wastewater, although they differed in sensitivity. The pattern of recovery efficiency for adenoviruses, coronaviruses, and influenza A viruses was consistent across methods, while distinct patterns were observed for coxsackieviruses. Promega produced higher median recovery efficiencies based on dPCR for all viruses except for coxsackieviruses, even though it had the highest dPCR inhibition. We suggest caution in applying Nanotrap to new targets, based on the low recovery of coxsackievirus B5 compared to the other viruses. We also quantified the endogenous indicators PMMoV and Carjivirus (formerly crAssphage), illustrating how normalization could either improve or worsen the comparison of virus concentrations measured by different methods. These findings can guide the selection of concentration and extraction methods for wastewater monitoring based on the properties of target viruses, thus enhancing pandemic preparedness. Synopsis StatementBenchmarking scalable concentration and extraction methods on respiratory viruses with diverse properties facilitates the rapid application of wastewater-based surveillance to emerging viruses.

microbiology↗

bioRxiv2023

Differential laboratory passaging of SARS-CoV-2 viral stocks impacts the in vitro assessment of neutralizing antibodies

Viral populations in natural infections can have a high degree of sequence diversity, which can directly impact immune escape. However, antibody potency is often tested in vitro with a relatively clonal viral populations, such as laboratory virus or pseudotyped virus stocks, which may not accurately represent the genetic diversity of circulating viral genotypes. This can affect the validity of viral phenotype assays, such as antibody neutralization assays. To address this issue, we tested whether recombinant virus carrying SARS-CoV-2 spike (VSV-SARS-CoV-2-S) stocks could be made more genetically diverse by passage, and if a stock passaged under selective pressure was more capable of escaping monoclonal antibody (mAb) neutralization than unpassaged stock or than viral stock passaged without selective pressures. We passaged VSV-SARS-CoV-2-S four times concurrently in three cell lines and then six times with or without polyclonal antiserum selection pressure. All three of the monoclonal antibodies tested neutralized the viral population present in the unpassaged stock. The viral inoculum derived from serial passage without antiserum selection pressure was neutralized by two of the three mAbs. However, the viral inoculum derived from serial passage under antiserum selection pressure escaped neutralization by all three mAbs. Deep sequencing revealed the rapid acquisition of multiple mutations associated with antibody escape in the VSV-SARS-CoV-2-S that had been passaged in the presence of antiserum, including key mutations present in currently circulating Omicron subvariants. These data indicate that viral stock that was generated under polyclonal antiserum selection pressure better reflects the natural environment of the circulating virus and may yield more biologically relevant outcomes in phenotypic assays.

molecular biology↗

bioRxiv2020

Two sides of a coin: a Zika virus mutation selected in pregnant rhesus macaques promotes fetal infection in mice but at a cost of reduced fitness in nonpregnant macaques and diminished transmissibility by vectors

Although fetal death is now understood to be a severe outcome of congenital Zika syndrome, the role of viral genetics is still unclear. We sequenced Zika virus (ZIKV) from a rhesus macaque fetus that died after inoculation and identified a single intra-host mutation, M1404I, in the ZIKV polyprotein, located in NS2B. Targeted sequencing flanking position 1404 in 9 additional macaque mothers and their fetuses identified M1404I at sub-consensus frequency in the majority (5 of 9, 56%) of animals and some of their fetuses. Despite its repeated presence in pregnant macaques, M1404I occurs rarely in humans since 2015. Since the primary ZIKV transmission cycle is human-mosquito-human, mutations in one host must be retained in the alternate host to be perpetuated. We hypothesized that ZIKV I1404 increases fitness in non-pregnant macaques and pregnant mice but is less efficiently transmitted by vectors, explaining its low frequency in humans during outbreaks. By examining competitive fitness relative to M1404, we observed that I1404 produced lower viremias in non-pregnant macaques and was a weaker competitor in tissues. In pregnant wildtype mice ZIKV I1404 increased the magnitude and rate of placental infection and conferred fetal infection, contrasting with M1404, which was not detected in fetuses. Although infection and dissemination rates were not different, Ae. aegypti transmitted ZIKV I1404 more poorly than M1404. Our data highlight the complexity of arbovirus mutation-fitness dynamics, and suggest that intrahost ZIKV mutations capable of augmenting fitness in pregnant vertebrates may not necessarily spread efficiently via mosquitoes during epidemics. IMPORTANCEAlthough Zika virus infection of pregnant women can result in congenital Zika syndrome, the factors that cause the syndrome in some but not all infected mothers are still unclear. We identified a mutation that was present in some ZIKV genomes in experimentally inoculated pregnant rhesus macaques and their fetuses. Although we did not find an association between the presence of the mutation and fetal death, we performed additional studies with it in non-pregnant macaques, pregnant mice, and mosquitoes. We observed that the mutation increased the ability of the virus to infect mouse fetuses but decreased its capacity to produce high levels of virus in the blood of non-pregnant macaques and to be transmitted by mosquitoes. This study shows that mutations in mosquito-borne viruses like ZIKV that increase fitness in pregnant vertebrates may not spread in outbreaks when they compromise transmission via mosquitoes and fitness in non-pregnant hosts.

microbiology↗

bioRxiv2020

Single amino acid mutations effect Zika virus replication in vitro and virulence in vivo

The 2014-2016 Zika virus (ZIKV) epidemic in the Americas resulted in large deposits of next-generation sequencing data from clinical samples. This resource was mined to identify emerging mutations and trends in mutations as the outbreak progressed over time. Information on transmission dynamics, prevalence and persistence of intra-host mutants, and the position of a mutation on a protein were then used to prioritize 544 reported mutations based on their ability to impact ZIKV phenotype. Using this criteria, six mutants (representing naturally occurring mutations) were generated as synthetic infectious clones using a 2015 Puerto Rican epidemic strain PRVABC59 as the parental backbone. The phenotypes of these naturally occurring variants were examined using both cell culture and murine model systems. Mutants had distinct phenotypes, including changes in replication rate, embryo death, and decreased head size. In particular, a NS2B mutant previously detected during in vivo studies in rhesus macaques was found to cause lethal infections in adult mice, abortions in pregnant females, and increased viral genome copies in both brain tissue and blood of female mice. Additionally, mutants with changes in the region of NS3 that interfaces with NS5 during replication displayed reduced replication in the blood of adult mice. This analytical pathway, integrating both bioinformatic and wet lab experiments, provides a foundation for understanding how naturally occurring single mutations affect disease outcome and can be used to predict the of severity of future ZIKV outbreaks. Author summaryTo determine if naturally occurring individual mutations in the Zika virus epidemic genotype effect viral virulence or replication rate in vitro or in vivo, we generated an infectious clone representing the epidemic genotype of stain Puerto Rico, 2015. Using this clone, six mutants were created by changing nucleotides in the genome to cause one to two amino acid substitutions in the encoded proteins. The six mutants we generated represent mutations that differentiated the early epidemic genotype from genotypes that were either ancestral or that occurred later in the epidemic. We assayed each mutant for changes in growth rate, and for virulence in adult mice and pregnant mice. Three of the mutants caused catastrophic embryo effects including increased embryonic death or significant decrease in head diameter. Three other mutants that had mutations in a genome region associated with replication resulted in changes in in vitro and in vivo replication rates. These results illustrate the potential impact of individual mutations in viral phenotype.

microbiology↗