Field assessment of the risk posed by Diorhabda elongata, a biocontrol agent for control of saltcedar (Tamarix spp.), to a nontarget plant, Frankenia salina

The biological control program for saltcedar (Tamarix spp.) has led to open releases of a specialist beetle (Chrysomelidae: Diorhabda elongata) in several research locations, but the controversy over potential impacts to native, nontarget plants of the genus Frankenia remains unresolved. To assess the potential for nontarget impacts under Weld conditions, we installed cultivated Frankenia spp. (primarily two forms of Frankenia salina but also including Frankenia jamesii) at locations in Nevada and Wyoming where D. elongata densities and saltcedar defoliation were expected to be very high, so insects would be near starvation with high probability of attacking nontargets if these were suitable hosts. Subsequent insect abundance was high, and only minor impact (\u3c4% foliar damage) was observed on both forms of F. salina under these ‘worst case’ conditions; there was no impact to F. jamesii. No oviposition nor larval development were observed on any plants, there was no dieback of damaged F. salina stems, and plants continued growing once insect populations subsided. These results under ‘natural’ Weld conditions contrast with caged host-range tests in which feeding, development and minor oviposition occurred on the nontarget plant. Other ecological factors, such as distance from target plants to natural Frankenia spp. populations, inhospitable conditions for agent survival in such sites, and intrinsic insect behavior that makes colonization and/or genetic adaptation highly unlikely, lead us to conclude that nontarget impacts following program implementation will be insignificant or absent. Host range testing of new agents, while necessary to ensure safety, must put greater attention on assessing the ecological context where agents will be establishing, and on balancing speculated risks against potential benefits of biological control

Pathophysiological Response to SARS-CoV-2 Infection Detected by Infrared Spectroscopy Enables Rapid and Robust Saliva Screening for COVID-19

Fourier transform infrared (FTIR) spectroscopy provides a (bio)chemical snapshot of the sample, and was recently used in proof-of-concept cohort studies for COVID-19 saliva screening. However, the biological basis of the proposed technology has not been established. To investigate underlying pathophysiology, we conducted controlled infection experiments on Vero E6 cells in vitro and K18-hACE2 mice in vivo. Potentially infectious culture supernatant or mouse oral lavage samples were treated with ethanol or 75% (v/v) Trizol for attenuated total reflectance (ATR)-FTIR spectroscopy and proteomics, or RT-PCR, respectively. Controlled infection with UV-inactivated SARS-CoV-2 elicited strong biochemical changes in culture supernatant/oral lavage despite a lack of viral replication, determined by RT-PCR or a cell culture infectious dose 50% assay. Nevertheless, SARS-CoV-2 infection induced additional FTIR signals over UV-inactivated SARS-CoV-2 infection in both cell and mouse models, which correspond to aggregated proteins and RNA. Proteomics of mouse oral lavage revealed increased secretion of kallikreins and immune modulatory proteins. Next, we collected saliva from a cohort of human participants (n = 104) and developed a predictive model for COVID-19 using partial least squares discriminant analysis. While high sensitivity of 93.48% was achieved through leave-one-out cross-validation, COVID-19 patients testing negative on follow-up on the day of saliva sampling using RT-PCR was poorly predicted in this model. Importantly, COVID-19 vaccination did not lead to the misclassification of COVID-19 negatives. Finally, meta-analysis revealed that SARS-CoV-2 induced increases in the amide II band in all arms of this study and in recently published cohort studies, indicative of altered β-sheet structures in secreted proteins. In conclusion, this study reveals a consistent secretory pathophysiological response to SARS-CoV-2, as well as a simple, robust method for COVID-19 saliva screening using ATR-FTIR