Copper Oxide Nanoparticle-Based Immunosensor for Zearalenone Analysis by Combining Automated Sample Pre-Processing and High-Throughput Terminal Detection

A rapid and high-throughput fluorescence detection method for zearalenone (ZEN) based on a CuO nanoparticle (NP)-assisted signal amplification immunosensor was developed using an automated sample pretreatment and signal conversion system. CuO NPs with high stability and biocompatibility were used as carriers to immobilize anti-ZEN antibodies. The obtained CuO NP-anti-ZEN can maintain the ability to recognize target toxins and act as both a signal source and carrier to achieve signal conversion using automated equipment. In this process, target toxin detection is indirectly transformed to Cu2+ detection because of the large number of Cu2+ ions released from CuO NPs under acidic conditions. Finally, a simple and high-throughput fluorescence assay based on a fluorescent tripeptide molecule was employed to detect Cu2+, using a multifunctional microporous plate detector. A good linear relationship was observed between the fluorescence signal and the logarithm of ZEN concentration in the range of 16.0–1600.0 μg/kg. Additionally, excellent accuracy with a high recovery yield of 99.2–104.9% was obtained, which was concordant with the results obtained from LC-MS/MS of naturally contaminated samples. The CuO NP-based assay is a powerful and efficient screening tool for ZEN detection and can easily be modified to detect other mycotoxins.

Tutorial: Guidelines for Single-Cell RT-qPCR

Reverse transcription quantitative PCR (RT-qPCR) has delivered significant insights in understanding the gene expression landscape. Thanks to its precision, sensitivity, flexibility, and cost effectiveness, RT-qPCR has also found utility in advanced single-cell analysis. Single-cell RT-qPCR now represents a well-established method, suitable for an efficient screening prior to single-cell RNA sequencing (scRNA-Seq) experiments, or, oppositely, for validation of hypotheses formulated from high-throughput approaches. Here, we aim to provide a comprehensive summary of the scRT-qPCR method by discussing the limitations of single-cell collection methods, describing the importance of reverse transcription, providing recommendations for the preamplification and primer design, and summarizing essential data processing steps. With the detailed protocol attached in the appendix, this tutorial provides a set of guidelines that allow any researcher to perform scRT-qPCR measurements of the highest standard.

An optimized stepwise algorithm combining rapid antigen and RT-qPCR for screening of COVID-19 patients

Background & aim We investigated the combination of rapid antigen detection (RAD) and RT-qPCR assays in a stepwise procedure to optimize the detection of COVID-19. Methods From August 2020 to November 2020, 43,399 patients were screened in our laboratory for COVID-19 diagnostic by RT-qPCR using nasopharyngeal swab. Overall, 4,691 of the 43,399 were found to be positive, and 200 were retrieved for RAD testing allowing comparison of diagnostic accuracy between RAD and RT-qPCR. Cycle threshold (Ct) and time from symptoms onset (TSO) were included as covariates. Results The overall sensitivity, specificity, PPV, NPV, LR-, and LR+ of RAD compared with RT-qPCR were 72% (95%CI 62%–81%), 99% (95% CI95%–100%), 99% (95%CI 93%–100%), and 78% (95%CI 70%–85%), 0.28 (95%CI 0.21–0.39), and 72 (95%CI 10–208) respectively. Sensitivity was higher for patients with Ct ≤ 25 regardless of TSO: TSO ≤ 4 days 92% (95%CI 75%–99%), TSO > 4 days 100% (95%CI 54%–100%), and asymptomatic 100% (95%CI 78–100%). Overall, combining RAD and RT-qPCR would allow reducing from only 4% the number of RT-qPCR needed. Conclusions This study highlights the risk of misdiagnosing COVID-19 in 28% of patients if RAD is used alone. A stepwise analysis that combines RAD and RT-qPCR would be an efficient screening procedure for COVID-19 detection and may facilitate the control of the outbreak.

A-169 Remote Cognitive Screening: A Preliminary Study of Location Administration of the Boston Cognitive Assessment (BoCA)

Objective Digital, remote, cognitive assessment has become crucial for efficient screening of patients cognitive concerns. The Boston Cognitive Assessment (BoCA) is a brief, digital, global screening instrument that can be administered both in-office on a laptop, or remotely from patients’ homes. Potential differences in performance from completing the BoCA in-office versus completing it at home remain uninvestigated. As such, this study aimed to compared performances across these settings among demographically and cognitively matched patient samples. Method Data from 35 cognitively healthy participants who completed the BoCA (18 administered in-office; 17 remotely administered) were retroactively collected; groups were matched by age, education, gender, ethnicity, and global cognitive functioning based on their scores on a separate screening instrument. Overall BoCA scores (total = 30) as well as performance on the eight BoCA subscales (Immediate Recall, Delayed Recall, Verbal Reasoning, Visuospatial Reasoning, Executive Functions, Attention, Mental Math, and Orientation) were compared using nonparametric testing. Results A Contingency analysis and an independent samples Mann–Whitney U test confirmed the demographic and cognitive similarities between the two groups. Comparisons of BoCA scores revealed no differences in total scores or any of the BoCA subscales between those who completed the BoCA in-office and those who completed it remotely. Conclusion Results from the present study suggest that performance on the BoCA is not influenced by one’s environment at the time of administration. This further adds to the utility of the BoCA as a remote, self-administered, global screening instrument, and may support its adoption in settings where serial screening is indicated.

Surveillance on Healthcare Workers During the First Wave of SARS-CoV-2 Pandemic in Italy: The Experience of a Tertiary Care Pediatric Hospital

Healthcare workers (HCWs) play a central role in handling the ongoing coronavirus disease 2019 (COVID-19) pandemic. Monitoring HCWs, both symptomatic and asymptomatic, through screening programs, are critical to avoid the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the hospital environment to rapidly identify and isolate infected individuals and to allow their prompt return to work as soon as necessary. We aim to describe our healthcare surveillance experience (April 2–May 6, 2020) based on a combined screening consisting of real-time PCR (RT-PCR) on nasopharyngeal (NP) swabs and rapid serologic tests (RST) for SARS-CoV-2 in all HCWs of Meyer Children's University Hospital in Florence. Among the analyzed workers, 13/1690 (0.8%), all of them without clinical manifestations, was found positive for SARS-CoV-2 by using RT-PCR on NP swab: 8/1472 (0.5%) were found positive during the screening, 1/188 (0.5%) during contact with a positive individual (p > 0.05 vs. screening group), while 4/30 (13.3%) were found positive on the day of re-admission at work after an influenza-like-illness (p < 0.05). Concerning working areas, the majority of RT-PCR positivity (12/13) and serologic positivity (34/42) was found in non-COVID-19 dedicated areas (p > 0.05 vs. COVID-19 dedicated areas). No cases were registered among non-patients-facing workers (p = 0.04 vs. patient-facing group). Nurses and residents represented, respectively, the working role with the highest and lowest percentage of RT-PCR positivity. In conclusion, accurate surveillance is essential to reduce virus spread among HCWs, patients, and the community and to limit the shortage of skilled professionals. The implementation of the surveillance system through an efficient screening program was offered to all professionals, regardless of the presence of clinical manifestations and the level of working exposure risk, maybe wise and relevant.

PL-4 (CIP596131.4): an Improved Potato Haploid Inducer

Dihaploid production from elite tetraploid cultivars is key to both traditional and novel breeding approaches that seek to simplify potato genetics. For this purpose, efficient and widely compatible haploid inducers (HIs) are needed. We compared PL-4, a new HI developed at the International Potato Center, to known HIs IvP101 and IvP35. By pollination of elite tetraploid breeding lines, we showed that PL-4 performed significantly better and had a homogeneous response regardless of the genetic background of the pistillate parents, on the most important efficiency traits—number of dihaploids per 100 fruits and haploid induction rate. Moreover, PL-4 exhibited a reduced proportion of hybrid seeds, a convenient trait for efficient screening. In this context, we recommend PL-4 as an enhanced HI for the potato breeding community.