[A new approach to the epidemiological control of infectious diseases in the Russian population].

The article describes a development related to the field of public health and molecular biology, in particular, medical diagnostics. We present the Isascreen-8 portable analyzer (Registration Certificate No. RZN 2022/17322, May 24, 2022) and its application for rapid diagnostics of a new coronavirus infection with the use of commercially available sets IsoAmp SARS-CoV-2 (Lytech Co. Ltd., Russia), and also our own development TB-IZATEST (Invention Application No. 2022133809, December 22, 2022) for diagnostics of tuberculosis pathogen. The approach proposed in this article can be used for rapid detection of genetic material (DNA/RNA) of Mycobacterium tuberculosis and SARS-CoV-2 in biological samples using the method of loop isothermal amplification in less than 20 minutes, and also as a universal platform for detection of genetic material of other pathogens in a biological sample. Using the proposed approach, various research tasks for epidemiological monitoring of tuberculosis and new coronavirus infection, qualitative and quantitative analysis of bacterial and viral load in samples, including evaluation of the effectiveness of the prescribed antibiotic therapy regimen, can be solved. The advantage is that this method can be used not only in diagnostic laboratories, but also in field laboratories in the most remote regions of Russia if the mandatory sanitary and epidemiological requirements are observed. With sufficient distribution, the proposed approach could help ensure epidemiological control of the prevalence of these socially significant infections.

Fluorescence imaging of cells using long-range electromagnetic surface waves for excitation.

We present a depth-localized illumination technique for wide-field fluorescence microscopy, based on long-range optical surface waves. This technique allows one to excite the fluorescence only in a thin near-substrate layer of the specimen. Our experimental setup is compatible with both upright and inverted microscopes. It provides fluorescent microscopic images, which are superior to the epifluorescence ones in signal-to-noise ratio, contrast, and detail. We demonstrate the applicability of our technique for imaging both bacterial and eukaryotic cells (E. coli and HeLa, respectively).

Two novel transcriptional reporter systems for monitoring Helicobacter pylori stress responses.

Helicobacter pylori, a human pathogen linked to many stomach diseases, is well adapted to colonize aggressive gastric environments, and its virulence factors contribute this adaptation. Here, we report the construction of two novel H. pylori vectors, pSv2 and pSv4, carrying a reporter gene fused to the promoters of virulence factor genes for monitoring the response of single H. pylori cells to various stresses. H. pylori cryptic plasmids were modified by the introduction of the Escherichia coli origin of replication, chloramphenicol resistance cassette, and promoterless gfp gene to produce E. coli/H. pylori shuttle vectors. The promoter regions of vacA and ureA genes encoding well-characterized H. pylori virulence factors were fused to the promoterless gfp gene. Recording the GFP fluorescence signal from the genetically modified H. pylori cells immobilized in specifically designed microfluidic devices revealed the response of transcriptional reporter systems to osmotic stress, acidic stress, elevated Ni2+ concentration or iron chelation. Our observations validate the utility of the pSv2 and pSv4 vectors to monitor the regulation of virulence factor genes in diverse strains and clinical isolates of H. pylori.