[Digital PCR as a Highly Sensitive Diagnostic Tool: A Review]

Digital PCR (dPCR) is a nucleic acid quantification method that is widely used in genetic analysis. One of the most significant advantages of dPCR over other methods is the possibility of absolute quantitative determination of genetic material without construction of calibration curves, which allows one to detect even single molecules of nucleic acids, and, hence, provides early diagnosis of diseases. One specific characteristic of dPCR is the detection of the analyzed biological object in each microreaction, followed by the presentation of the analysis results in a binary system, thereby giving the method its name. The key aspects of developing the dPCR method, i.e., from the first devices based on microfluidic chip technology to modern systems capable of measuring a target at a concentration of up to 1 in 100000 copies are shown in the current work. We analyzed the data on the detection of various pathogens using dPCR, as well as summarizing various study results demonstrating the innovativeness of this method. Both the possibilities of multiplex dPCR analysis and its potential in clinical practice are presented. This review also addresses the issue of the role of dPCR in the development of noninvasive methods for analysis of oncological diseases. Possible ways of developing dPCR technology were emphasized, including its use as a "point-of-care" system.

Genetic markers of children asthma: predisposition to disease course variants

Asthma is a heterogeneous and often difficult to treat condition that results in a disproportionate cost to healthcare systems. Children with severe asthma are at increased risk for adverse outcomes including medication-related side effects, life-threatening exacerbations, and impaired quality of life. An important therapeutic focus is to achieve disease control, which is supposed to involve a personalized approach to treatment of asthma of any severity. Asthma is a multifactorial disease with a significant genetic determinant, however, the inheritance of asthma has not been fully elucidated. Polymorphic genes of inflammatory mediators, including cytokines, play an important role in developing various disease forms. In the current study, large-scale original data on the prevalence of cytokine gene genotypes (IL2, IL4, IL5, IL6, IL10, IL12, IL13, IL17A, IL31, IL33, IFNG, TNFA) among Russian children with asthma in Krasnoyarsk region have been obtained. Genotyping was carried out using real-time PCR. We identified markers predisposing to the development of different variants of the course of childhood asthma: the CT genotype and T allele of IL4 rs2243250 are associated with asthma (p < 0.05), especially in mild asthma and in controlled asthma. The TT genotype and allele T of IL13 rs1800925 are associated with severe and uncontrolled asthma (p < 0.05). The AA genotype of IL17A rs2275913, the TT genotype of IFNG rs2069705 and allelic A variants of TNFA rs1800629 are associated with mild asthma, and the TT genotype of IFNG rs2069705 is additionally associated with controlled asthma. The results obtained will supplement information on the prevalence of polymorphic variants of the cytokine genes in the Russian population and in asthma patients with different disease courses, which is likely to be used in order to shape a plan for Public Health Authority to prevent the development of severe uncontrolled asthma and to optimize personalized therapy.

Design of bioluminescent biosensors for assessing contamination of complex matrices

The presence of potentially toxic xenobiotics in complex matrices has become rather the rule than the exception. Therefore, there is a need for highly sensitive inexpensive techniques for analyzing environmental and food matrices for toxicants. Enzymes are selectively sensitive to various toxic compounds, and, thus, they can be used as the basis for detection of contaminants in complex matrices. There are, however, a number of difficulties associated with the analysis of complex matrices using enzyme assays, including the necessity to take into account properties and effects of the natural components of the test media for accurate interpretation of results. The present study describes the six-stage procedure for designing new enzyme sensors intended for assessing the quality of complex matrices. This procedure should be followed both to achieve the highest possible sensitivity of the biosensor to potentially toxic substances and to minimize the effect of the uncontaminated components of complex mixtures on the activity of the biosensor. The proposed strategy has been tested in designing a bioluminescent biosensor for integrated rapid assessment of the safety of fruits and vegetables. The biosensor is based on the coupled enzyme system NAD(P)H:FMN-oxidoreductase and luciferase as the biorecognition element. The study describes methods and techniques for attaining the desired result in each stage. The proposed six-stage procedure for designing bioluminescent enzyme biosensors can be used to design the enzymatic biosensors based on other enzymes.

Pesticides: formulants, distribution pathways and effects on human health - a review

Pesticides are commonly used in agriculture to enhance crop production and control pests. Therefore, pesticide residues can persist in the environment and agricultural crops. Although modern formulations are relatively safe to non-target species, numerous theoretical and experimental data demonstrate that pesticide residues can produce long-term negative effects on the health of humans and animals and stability of ecosystems. Of particular interest are molecular mechanisms that mediate the start of a cascade of adverse effects. This is a review of the latest literature data on the effects and consequences of contamination of agricultural crops by pesticide residues. In addition, we address the issue of implicit risks associated with pesticide formulations. The effects of pesticides are considered in the context of the Adverse Outcome Pathway concept.

Principles for Construction of Bioluminescent Enzyme Biotests for Analysis of Complex Media

In this study, we formulated the principles of designing bioluminescent enzyme tests for assessing the quality of complex media, which consist in providing the maximum sensitivity to potentially toxic chemicals at a minimal impact of uncontaminated complex media. The developed principles served as a basis for designing a new bioluminescent method for an integrated rapid assessment of chemical safety of fruits and vegetables, which is based on using the luminous bacteria enzymes (NAD(P)H:FMN oxidoreductase and luciferase) as a test system.