Using the DNA recombination technique, a new bacterial strain Escherichia coli DAC-22 was derived, whose cells are able to carry out the heterologous expression of Bacillus thuringiensis diadenylate cyclase – the enzyme catalyzing the reaction of adenosine-5′-triphosphate (ATP) transformation into cyclic 3′,5′-diadenylate (cyclo-di-AMP). To derive the strain, E. coli “Rosetta (DE3) pLysS” cells were originally used as recipients of plasmid pET42a+ with the inserted gene disA encoding diadenylate cyclase of B. thuringiensis. The cells of the recombinant strain are able to produce heterologous diadenylate cyclase localized predominantly (by 90 %) in the fraction of the catalytically active inclusion bodies. The productivity of the new strain with respect to diadenylate cyclase structurally arranged as the inclusion bodies was 720 units/l of cultural fluid. The inclusion bodies formed by the newly engineered strain are intended for use in the technology of producing pharmacologically promising cyclo-di-AMP.

Colibacteriosis is an acute zoonotic disease manifested by septicaemia, toxemia, enteritis, body dehydration, and central nervous system damage. Depending on the presence of virulence factors and the nature of interaction with the intestinal mucosa, enterotoxigenic, enteroinvasive, enteropathogenic, and enterohemorrhagic E. coli are isolated. Enterotoxigenic strains of E. coli occupy one of the leading places in the etiological structure of calf colibacteriosis in many livestock farms of the Republic of Belarus. The main reason why this disease develops is the presence of thermolabile and thermostable toxins in the causative strain. The thermolabile toxin subunit B is a potent antigen that allows pet immunity to be acquired against E. coli-induced cattle diarrhea. Many foreign vaccines used against intestinal infections of cattle contain either a native or recombinant variant of the subunit B. As a result of the work, we have created a new strain of E. coli 42eLTB – the producer of the recombinant subunit B of the thermolabile toxin E. coli. The producing capacity of the obtained strain is 480 mg with 1 culture liquid liter, which exceeds the already known strains 1.37 times.

Using Recombinant DNA Technology, the novel bacterial recombinant strain Escherichia coli DAC-22, a source of diadenylate cyclase that catalyzes the transformation of adenosine-5′-triphosphate into cyclic 3′,5′-diadenylate (cyclo-di-AMP), was developed. The strain was derived by the transformation of E. coli Rosetta (DE3) pLysS cells with the recombinant plasmid pET42a+ wherein the disA gene responsible for the synthesis of the diadenylate cyclase of Bacillus thuringiensis was inserted. The producing capacity of the new strain with respect to diadenylate cyclase localized in catalytically active inclusion bodies equaled 720 units per liter of liquid culture. The newly engineered strain is destined for use in the technology related to the production of pharmaceutically promising cyclo-di-AMP.

COVID-19 pandemic caused by coronavirus SARS-CoV-2 affected virtually all life aspects in most countries and nations. During 2020 around 100 mln of Earth inhabitants contracted this morbid infection and 2 mln people died thereafter. It is natural therefore that many pharmaceutical companies around the globe have joined into the race aimed at elaboration of prophylactic antiviral vaccines. However, the option can not be ruled out that parenteral vaccines to counter rapidly mutating pandemic coronavirus may be designed hastily, neglecting due tests of remote side effects, so that in the long run they risk to be expelled from the marked due to doubtful safety and efficiency.As a real alternative to traditional vaccination techniques the present mini-review has proposed application of intranasal adjuvant nano-vaccine. If necessary, this approach may be complemented with pharmacological inactivation of coronavirus under the impact of ribo-favipiravir, recombinant arginine deiminase, RNAse L or lactoferrin, as well as biogenic silver or copper nanoparticles - the preparations derived from up-to-date molecular biotechnological processes.