To develop a modern plague vaccine, we used hypo-endotoxic Yersinia pestis bacterial ghosts (BGs) with combinations of genes encoding the bacteriophage ɸX174 lysis-mediating protein E and/or holin-endolysin systems from λ or L-413C phages. Expression of the protein E gene resulted in the BGs that retained the shape of the original bacterium. Co-expression of this gene with genes coding for holin-endolysin system of the phage L-413C caused formation of structures resembling collapsed sacs. Such structures, which have lost their rigidity, were also formed as a result of the expression of only the L-413C holin-endolysin genes. A similar holin-endolysin system from phage λ containing mutated holin gene S and intact genes R-Rz coding for the endolysins caused generation of mixtures of BGs that had (i) practically preserved and (ii) completely lost their original rigidity. The addition of protein E to the work of this system shifted the equilibrium in the mixture towards the collapsed sacs. The collapse of the structure of BGs can be explained by endolysis of peptidoglycan sacculi. Immunizations of laboratory animals with the variants of BGs followed by infection with a wild-type Y. pestis strain showed that bacterial envelopes protected only cavies. BGs with maximally hydrolyzed peptidoglycan had a greater protectivity compared to BGs with a preserved peptidoglycan skeleton.
The paper considers the features of the innovative design and gas dynamics of the flow in the flow path of the cutting-separating turbine unit of the flax combine. On the basis of the combine tests, the possibility of using a turbine unit to ensure a stable movement of the working mixture in the pneumatic transport system of the combine was considered. To provide the necessary pressure characteristics, a method for designing a flow path is proposed on the basis of the hypothesis of the analogy of the action on the flow of a set of cutting sets with a centrifugal compressor blade. Stodola for turbomachines and calculation of ideal gas flow on the axisymmetric surface of the interscapular channel
Task – to study the main properties toxigenic strain of Corynebacterium diphtheriae circulated in postepidemic period from biofilm culture. It was shown that Diphtheriae causative agent has the ability to biofilm formation that is accompanied by exopolysaccharide matrix formation. This combines with changes of morphologic properties (decrease of bacteria sizes), cultures properties (decrease of colonies sizes, R-S-dissociation) and antibiotic susceptibility. The most effective towards Diphtheriae infection causative microorganism are cefotaxime, gentamycin, linkomycin, kanamycin and cefazolin, because they have no changes in susceptibility of Corynebacterium diphtheria? in the biofilm structure.
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