Create a method for highly sensitive, selective, rapid, and easy-to-use detection and identification of economically significant potato pathogens, including viruses, bacteria and oomycetes, be it single pathogen, or a range of various pathogens occurring simultaneously. Test-systems for real-time PCR, operating in the unified amplification regime, have been developed for Phytophthora infestans, Pectobacterium atrosepticum, Dickeya dianthicola, Dickeya solani, Ralstonia solanacearum, Pectobacterium carotovorum, Clavibacter michiganensis subsp. sepedonicus, potato viruses Y (ordinary and necrotic forms as well as indiscriminative test system, detecting all forms), A, X, S, M, potato leaf roll virus, potato mop top virus, and potato spindle tuber viroid. The test-systems (including polymerase and revertase) were immobilized and lyophilized in miniature microreactors (1.2 μl) on silicon DNA/RNA microarrays (micromatrices) to be used with a mobile AriaDNA^® amplifier. Preloaded 30-reaction micromatrices having shelf life of 3 and 6 months (for RNA- and DNA-based pathogens, respectively) at room temperature with no special conditions were successfully tested on both reference and field samples in comparison with traditional ELISA and microbiological methods, showing perfect performance and sensitivity (1 pg). The accurate, rapid and user-friendly diagnostic system in a micromatrix format may significantly contribute to pathogen screening and phytopathological studies.

Atomic force microscopy (AFM) and photon correlation spectroscopy (PCS) were used for monitoring of the procedure for cytochrome CYP11A1 monomerization in solution without phospholipids. It was shown that the incubation of 100 μM CYP11A1 with 12% Emulgen 913 in 50 mM KP, pH 7.4, for 10 min at T = 22°C leads to dissociation of hemoprotein aggregates to monomers with the monomerization degree of (82 ± 4)%. Following the monomerization procedure, CYP11A1 remained functionally active. AFM was employed to detect and visualize the isolated proteins as well as complexes formed between the components of the cytochrome CYP11A1-dependent steroid hydroxylase system. Both Ad and AdR were present in solution as monomers. The typical heights of the monomeric AdR, Ad and CYP11A1 images were measured by AFM and were found to correspond to the sizes 1.6 ± 0.2 nm, 1.0 ± 0.2 nm and 1.8 ± 0.2 nm, respectively. The binary Ad/AdR and AdR/CYP11A1_mon complexes with the heights 2.2 ± 0.2 nm and 2.8 ± 0.2 nm, respectively, were registered by use of AFM. The Ad/CYP11A1_mon complex formation reaction was kinetically characterized based on optical biosensor data. In addition, the ternary AdR/Ad/CYP11A1 complexes with a typical height of 4 ± 1 nm were AFM registered.

Viral and bacterial diseases of potato cause significant yield loss worldwide. The current data on the occurrence of these diseases in Russia do not provide comprehensive understanding of the phytosanitary situation. Diagnostic systems based on disposable stationary open qPCR micromatrices intended for the detection of eight viral and seven bacterial/oomycetal potato diseases have been used for wide-scale screening of target pathogens to estimate their occurrence in 11 regions of Russia and to assess suitability of the technology for high-throughput diagnostics under conditions of field laboratories. Analysis of 1025 leaf and 725 tuber samples confirmed the earlier reported data on the dominance of potato viruses Y, S, and M in most regions of European Russia, as well as relatively high incidences of Clavibacter michiganensis subsp. sepedonicus, Pectobacterium atrosepticum, and P. carotovorum subsp. carotovorum, and provided detailed information on the phytosanitary status of selected regions and geographical spread of individual pathogens. Information on the occurrence of mixed infections, including their composition, was the first data set of this kind for Russia. The study is the first large-scale screening of a wide range of potato pathogens conducted in network mode using unified methodology and standardized qPCR micromatrices. The data represent valuable information for plant pathologists and potato producers and indicate the high potential of the combined use of matrix PCR technology and network approaches to data collection and analysis with the view to rapidly and accurately assess the prevalence of certain pathogens, as well as the phytosanitary state of large territories.

Atomic force microscopy (AFM) study of the oligomeric state of CYP102A1 was carried out in three different environmental conditions – liquid, air and vacuum. It was shown that usage of a standard probe with a radius of curvature of 10 nm allowed determination of the monomers-to-oligomers ratio, α ≈ 0.5 : 0.5, in these three media, but it wasn't possible to estimate the oligomerization degree more precisely. Application of a supersharp probe with a radius of curvature of 2 nm made it possible not only to obtain data on the ratio of monomers-to-oligomers but also to obtain the approximate ratio between dimers, trimers and tetramers 0.3 : 0.1 : 0.1, but only in vacuum.

Atomic force microscopy is one of the most perspective methods for determination of the structure of proteins and their complexes. The vertical resolution of this method is about 0.1 nm, which is close to X-ray resolution. At the same time, the lateral resolution, determining by broadening effect of a standard AFM probe, is not very high—about 20–50 nm, depending on probe geometry. Naturally, the probe tip broadening effect leads to substantial enhancement of measured protein volume. In this study, a comparative analysis of sizes of the protein putidaredoxin reductase (PdR) obtained by the use of two AFM probe types, standard and supersharp, was undertaken. Usage of standard probes enabled to correctly measure the height of PdR while the volume of this protein was measured with considerably (more than one order) enhancement. It was shown that application of supersharp AFM probes results in the lowering of measured protein height; at the same time, the measured protein volume is more exact and appears to be close to RSA data. Therefore, to obtain exact data on protein volume and height, these two parameters should be measured by use of both supersharp probes and standard geometry probes.

Possibility of detection and identification of hepatitis C viral particles with mass spectrometry (MS) in combination with atomic force microscopy (AFM) had been investigated. AFM/MS approach is based on two technologies: 1. AFM-biospecific fishing that allows to detect, concentrate from solution and to count protein complexes on a surface of AFM-nanochip; 2. mass spectrometric identification of these complexes. AFM-biospecific fishing of HCVcoreAg from solution was carried onto surface of AFM-nanochips with immobilized anti-HCVcoreAg. It was shown that HCVcoreAg/anti-HCVcoreim complexes were formed onto AFM-nanochips in quantity sufficient for mass spectrometric identification. Thus, AFM/MS approach allows to identify fragments of hepatitis C virus fished onto a surface of AFM-nanochip from serum.