Saliva is one of the most significant biological liquids for the development of a simple, rapid, and non-invasive biosensor for training load diagnostics. There is an opinion that enzymatic bioassays are more relevant in terms of biology. The present paper is aimed at investigating the effects of saliva samples, upon altering the lactate content, on the activity of a multi-enzyme, namely lactate dehydrogenase + NAD(P)H:FMN-oxidoreductase + luciferase (LDH + Red + Luc). Optimal enzymes and their substrate composition of the proposed multi-enzyme system were chosen. During the tests of the lactate dependence, the enzymatic bioassay showed good linearity to lactate in the range from 0.05 mM to 0.25 mM. The activity of the LDH + Red + Luc enzyme system was tested in the presence of 20 saliva samples taken from students whose lactate levels were compared by the Barker and Summerson colorimetric method. The results showed a good correlation. The proposed LDH + Red + Luc enzyme system could be a useful, competitive, and non-invasive tool for correct and rapid monitoring of lactate in saliva. This enzyme-based bioassay is easy to use, rapid, and has the potential to deliver point-of-care diagnostics in a cost-effective manner.

The paper considers the creation of a diagnostic system based on morphological and biophysical indicators that allows us to understand the influence of the climatic component, as well as stress factors on the general physiological state of young people for further correction of preventive measures and preservation of the health of the peoples of the Far North. The aim of the study is a comprehensive assessment of the health of young people living in the Far North based on the results of bioluminescent saliva activity, stress-emotional state obtained before and after intense mental stress, as well as anthropometric and bioimpedance indicators. 117 students of the Medical Institute of Surgut State University took part in the survey at a young age (18-23 years) during the educational process (rest) and during the examination session (mental load) in the first half of the year of study (autumn-winter 2021). The stress-emotional state was assessed using the Spielberger-Khanin test, the functional state of students They were studied using bioluminescent salivary fluid testing, anthropometric and bioimpedance methods. Samples were obtained by spitting unstimulated saliva into a test tube. As a result of the study, regional features of the physique of young people were revealed, which indicates the formation of a phenotype adapted to living conditions in the northern region. The relationship between the stress-emotional status of adolescents and the level of inhibition of the bioluminescent enzymatic system by saliva samples taken before and after mental stress was shown. The value of the residual glow had an increased indicator for the state of rest and significantly reduced the intensity of the bioluminescent glow under mental stress. The methodological development obtained in the future will make it possible to effectively manage the methods and methods of diagnosing young people, taking into account the influence of external factors, climatic zones and conditions.

A new personalized approach is proposed to predict the professional suitability of railway transport workers under the influence of stressful factors, based on the study of the effect of salivary fluid of subjects before and after a work shift on the intensity of the glow of the bioenzyme reaction of luminous bacteria: NADH:FMN-oxidoreductase+luciferase. The integral method, which signals the magnitude of the stress effect, is based on changes in saliva components such as lactate, ions and cations, as well as nitrate and sulfate chlorides under the influence of stress. This made it possible to identify, using the example of Russian Railways dispatchers, a risk group and a group of stress-resistant workers, which is important to reduce accidents at Russian Railways. The conditions that reduce the stressful workload necessary for the development of effective measures for the prevention of stressful situations and the preservation of workers’ ability to work have been identified.