New bioluminescence pyrophosphate assay for high-sensitivity detection of food-borne pathogens

Detection of cellular metabolites by redox enzymatic cascades

Detection of cellular metabolites that are disease biomarkers is important for human healthcare monitoring and assessing prognosis and therapeutic response. Accurate and rapid detection of microbial metabolites and pathway intermediates is also crucial for the process optimization required for development of bioconversion methods using metabolically engineered cells. Various redox enzymes can generate electrons that can be employed in enzyme-based biosensors and in the detection of cellular metabolites. These reactions can directly transform target compounds into various readout signals. By incorporating engineered enzymes into enzymatic cascades, the readout signals can be improved in terms of accuracy and sensitivity. This review critically discusses selected redox enzymatic and chemoenzymatic cascades currently employed for detection of human- and microbe-related cellular metabolites including, amino acids, d-glucose, inorganic ions (pyrophosphate, phosphate, and sulfate), nitro- and halogenated phenols, NAD(P)H, fatty acids, fatty aldehyde, alkane, short chain acids, and cellular metabolites.

A Novel Approach to the Bioluminescent Detection of the SARS-CoV-2 ORF1ab Gene by Coupling Isothermal RNA Reverse Transcription Amplification with a Digital PCR Approach

The COVID-19 pandemic caused by the SARS-CoV-2 virus, which first emerged in December 2019, represents an ongoing global public health emergency. Here, we developed an improved and highly sensitive approach to SARS-CoV-2 detection via coupling bioluminescence in real-time (BART) and reverse-transcriptase loop-mediated amplification (RT-LAMP) protocols (RT-LAMP-BART) and was also compatible with a digital LAMP system (Rainsuit), which did not allow for real-time quantification but did, nonetheless, facilitate absolute quantification with a comparable detection limit of 10⁴ copies/mL. Through improving RNA availability in samples to ensure the target RNA present in reaction, we additionally developed a simulated digital RT-LAMP approach using this same principle to enlarge the overall reaction volume and to achieve real-time detection with a limit of detection of 10 copies/mL, and with further improvements in the overall dynamic range of this assay system being achieved through additional optimization.

Chemiluminescence assay for Listeria monocytogenes based on Cu/Co/Ni ternary nanocatalyst coupled with penicillin as generic capturing agent

Bacterial pathogen control is important in seafood production. In this study, a Cu/Co/Ni ternary nanoalloy (Cu/Co/Ni TNA) was synthesized using the oleylamine reducing method. It was found that Cu/Co/Ni TNA greatly enhanced the chemiluminescence (CL) signal of the hydroxylamine-O-sulfonic acid (HOSA)-luminol system. The CL properties of Cu/Co/Ni TNA were investigated systemically. The possible CL mechanism also was intensively investigated. Based on the enhanced CL phenomenon of Cu/Co/Ni TNA, a Cu/Co/Ni TNA, penicillin, and anti-L. monocytogenes (Listeria monocytogenes) antibody-based sandwich complex assay for detection of L. monocytogenes was established. In this sandwich CL assay, penicillin was employed to capture and enrich pathogenic bacteria with penicillin-binding proteins (PBPs) while anti-L. monocytogenes antibody was adopted as the specific recognition molecule to recognize L. monocytogenes. L. monocytogenes was detected sensitively based on this new Cu/Co/Ni TNA-HOSA-luminol CL system. The CL intensity was proportional to the L. monocytogenes concentration ranging from 2.0 × 10² CFU ml^-1 to 3.0 × 10⁷ CFU ml^-1 and the limit of detection wa 70 CFU ml^-1 . The reliability and potential applications of our method was verified by comparison with official methods and recovery tests in environment and food samples.