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Petrov, A.

Publications and source records attributed to Petrov, A..

2 recordsLinked to original sources

Scent dog identification of SARS-CoV-2 infections, similar across different body fluids

BackgroundThe main strategy to contain the current SARS-CoV-2 pandemic remains to implement a comprehensive testing, tracing and quarantining strategy until vaccination of the population is adequate. MethodsTen dogs were trained to detect SARS-CoV-2 infections in beta-propiolactone inactivated saliva samples. The subsequent cognitive transfer performance for the recognition of non-inactivated samples were tested on saliva, urine, and sweat in a randomised, double-blind controlled study. ResultsDogs were tested on a total of 5242 randomised sample presentations. Dogs detected non-inactivated saliva samples with a diagnostic sensitivity of 84% and specificity of 95%. In a subsequent experiment to compare the scent recognition between the three non-inactivated body fluids, diagnostic sensitivity and specificity were 95% and 98% for urine, 91% and 94% for sweat, 82%, and 96% for saliva respectively. ConclusionsThe scent cognitive transfer performance between inactivated and non-inactivated samples as well as between different sample materials indicates that global, specific SARS-CoV-2-associated volatile compounds are released across different body secretions, independently from the patients symptoms. FundingThe project was funded as a special research project of the German Armed Forces. The funding source DZIF-Fasttrack 1.921 provided us with means for biosampling.

animal behavior and cognition

Partial spontaneous intersubunit rotations in actively translating ribosomes

The ribosome is a molecular machine that adopts at least two global states during translation. Two main steps of translation, peptidyl transfer and translocation, are accompanied by counterclockwise and clockwise rotations of the two ribosomal subunits. However, when and why the ribosome alternates between these states remains unclear, with two well supported but conflicting hypotheses. Ribosomes may undergo a single cycle of forward and backward rotations per codon read. Alternatively, in addition to rotations caused by peptidyl transfer and translocation, ribosomes may undergo multiple full spontaneous rotations, with these rotations playing a critical role in elongation and specifically in translocation mechanism. We applied high-speed single-molecule TIRF microscopy to follow translation in real-time. Actively translating ribosomes undergo partial spontaneous rotations between three different rotational states. Spontaneous rotations are restricted prior to A-site tRNA decoding. Peptidyl transfer unlocks spontaneous rotations. Consequently, translocation proceeds via a novel rotational state induced by EF-G. Our results bridge both models and provide a coherent view of ribosome dynamics during translation.

biochemistry