Ultrasensitive detection of SARS-CoV-2 nucleocapsid protein using large gold nanoparticle-enhanced surface plasmon resonance

The COVID-19 pandemic has created urgent demand for rapid detection of the SARS-CoV-2 coronavirus. Herein, we report highly sensitive detection of SARS-CoV-2 nucleocapsid protein (N protein) using nanoparticle-enhanced surface plasmon resonance (SPR) techniques. A crucial plasmonic role in significantly enhancing the limit of detection (LOD) is revealed for exceptionally large gold nanoparticles (AuNPs) with diameters of hundreds of nm. SPR enhanced by these large nanoparticles lowered the LOD of SARS-CoV-2 N protein to 85 fM, resulting in the highest SPR detection sensitivity ever obtained for SARS-CoV-2 N protein

低温オーブントラッピングキャピラリーガスクロマトグラフィーによるヒト全血中アセトニトリル及びプロピオニトリルの高感度分析

We have developed a simple and sensitive method for determining acetonitrile and propionitrile in human whole blood using capillary gas chromatography (GC) with cryogenic oven trapping. After heating 0.5 ml of a whole blood sample containing both nitriles and 0.5 ml of distilled water in a 7-ml vial at 75℃ for 15 min, 5 ml of the headspace vapor was drawn into a 10-ml syringe and injected to GC with a flame thermionic detector. A sharp peak was obtained for acetonitrile at -10℃ of the initial oven temperature. The extraction efficiencies for acetonitrile and propionitrile were 0.27 and 0.40%, respectively. For quantitation of acetonitrile, propionitrile was used as internal standard, and vise versa. The calibration curves for both compounds gave good linearity in the range of 0.2-6 μg/ml whole blood. The detection limits (signal to noise ratio = 3) were 0.05μg/ml for acetonitrile and 0.01μg/ml for propionitrile. The coefficients of intra-day variations were 1.0% at 0.4μg/ml and 1.7% at 2μg/ml for acetonitrile; 7.1% at 0.4μg/m1 and 1.0 % at 2μg/ml for propionitrile. This method can be applicable for determining these nitriles in whole blood samples in acute and chronic intoxication cases.rights:日本法中毒学会rights:本文データは日本法中毒学会の許諾のもと掲載しています

Degradation of rRNA in BM-N cells from the silkworm Bombyx mori during abortive infection with heterologous nucleopolyhedroviruses

Cell lines derived from the silkworm, Bombyx mori, are only permissive for B. mori nucleopolyhedrovirus (NPV), with other NPVs generally resulting in abortive infection. Here, we demonstrate that rRNA of B. mori BM-N cells undergoes rapid degradation through site-specific cleavage upon infection with NPVs from Autographa californica (AcMNPV), Hyphantria cunea (HycuMNPV), Spodoptera exigua (SeMNPV) and Spodoptera litura (SpltMNPV). No significant decreases in cellular RNA were observed in Ld652Y, Se301, Sf9, SpIm and S2 cells infected with AcMNPV or HycuMNPV, indicating the response is unique to BM-N cells. A transient expression assay using a cosmid library of the HycuMNPV genome demonstrated that HycuMNPV P143 is responsible for rRNA degradation, which was also detected in BM-N cells transfected with plasmids expressing the P143 proteins from AcMNPV, SeMNPV and SpltMNPV. These results indicate that B. mori evolved to acquire a unique antiviral immune mechanism that is activated by P143 proteins from heterologous NPVs.</jats:p