Recombinant TBEV Protein E of the Siberian Subtype Is a Candidate Antigen in the ELISA Test System for Differential Diagnosis

The tick-borne encephalitis virus (TBEV) is one of the most common members of the Orthoflavivirus genus, which comprises the causative agents of severe diseases in humans and animals. Due to the expanding areas of orthoflavivirus infection, its differential diagnosis is highly demanded. Commercial test kits based on inactivated TBEV may not provide reliable differentiation between flaviviruses because of serological crossover in this genus. Application of recombinant domains (sE and dIII) of the TBEV Sukhar-strain protein E as antigens in an ELISA test system allowed us to identify a wide range of antibodies specific to different TBEV strains. We tested 53 sera from human patients with confirmed TBE diagnosis (the efficacy of our test system based on sE protein was 98%) and 56 sera from patients with other orthoflavivirus infections in which no positive ones were detected using our ELISA test system, thus being indicative of its 100% specificity. We also tested mouse and rabbit sera containing antibodies specific to 17 TBEV strains belonging to different subtypes; this assay exhibited high efficacy and differentiation ability in detecting antibodies against TBEV from other orthoflaviviruses such as Omsk hemorrhagic fever, Powassan, yellow fever, dengue, West Nile, Zika, and Japanese encephalitis viruses.

Damage to seeds by screw working bodies

Seed damage caused by screw working bodies of agricultural machines reduces the seed quality and increases the total cost of crop production. This paper describes the impact interaction of a particle with screw flights when seeds are fed into the transportation zone. There are velocity dependences during the impact and reflection of seeds on the screw surface at the maximum distance of the radius from the screw rotation axis. The potential energy lost by seeds when interacting with screw flights is determined. The paper considers the way transporting the seed material by screw working bodies impacts seed damage. The potential energy accumulated after impact by the reflecting surface and the particle depends on the magnitude and direction of the falling velocity to the screw belt, the auger geometric and kinematic parameters (the screw diameter; the inclination angle of the helix to the screw axis and the angular velocity), as well as the physical and mechanical properties of the particle and the reflecting surface (recovery and friction coefficients). Previous studies have shown that the critical angular velocity of the screw flight depends on the screw casing and the reduction factor of the circumferential velocity. In turn, the reduction factor depends on the transported seed material and the geometric parameters of the screw. It is possible to diminish the destruction of the seed material due to impact interaction with the working surface of the screw by reducing the inclination angle of the screw flight α, the angular speed of the screw rotation ω and its radius R. It also requires direct the seed flow closer to the rotation center. Reducing injury to seeds during transportation in a screw device requires a higher critical angular velocity of the screw. To increase the working angular velocity of the screw without exceeding its threshold of critical angular velocity, it is advisable to use screws with a large pitch and polymer screws with a wider pitch.

Development and characterization of chimera of yellow fever virus vaccine strain and Tick-Borne encephalitis virus

Tick-borne encephalitis virus (TBEV) is one of the most threatening pathogens which affects the human central nervous system (CNS). TBEV circulates widely in Northern Eurasia. According to ECDC, the number of TBE cases increase annually. There is no specific treatment for the TBEV infection, thus vaccination is the main preventive measure. Despite the existence of several inactivated vaccines currently being licensed, the development of new TBEV vaccines remains a leading priority in countries endemic to this pathogen. Here we report new recombinant virus made by infectious subgenomic amplicon (ISA) approach using TBEV and yellow fever virus vaccine strain (YF17DD-UN) as a genetic backbone. The recombinant virus is capable of effective replication in mammalian cells and induce TBEV-neutralizing antibodies in mice. Unlike the original vector based on the yellow fever vaccine strain, chimeric virus became neuroinvasive in doses of 107-106 PFU and can be used as a model of flavivirus neuroinvasiveness, neurotropism and neurovirulence. These properties of hybrid structures are the main factors limiting their practical use as vaccines platforms.