A Calorimetric Characterization of Cr(VI)-Reducing Arthrobacter oxydans

This is the first of a series of calorimetric studies designed to characterize and understand survival mechanisms of metal-reducing bacteria isolated from metal-polluted environments. In this paper we introduce a new concept of thermal spectrum of the endothermic melting of complex biological systems (e.g., proteins, nucleic acids, ribosomes, membrane structures) in intact cells. All thermal spectra measured are thermograms that describe the temperature dependence of heat capacity change of the complex systems of biologically active substances in bacterial cells. This new concept of thermal spectrum was applied to investigate spectral features from intact cells of Cr(VI)-reducer Arthrobacter oxydans at different points of their growth conditions and stages. Over the temperature range of 40–105°C, we observed that spectral changes are particularly significant in the 40–90°C interval. This may correspond to the orderly changes in subcellular structural elements: proteins, ribosomes and RNA, membranes, and various structural elements of the cell wall during different points of the growth cycle and growth conditions. Spectral changes in the 90–105°C region are less pronounced, implicating that the structural composition of DNA-Protein (DNP) complexes may change little

Comorbidity and Association of Posttraumatic Stress, Depression, Anxiety, and Somatic Complaints in COVID-19 Georgian Patients at the Beginning of Pandemic

Background: The global pandemic which the world has been facing for the past two years has demonstrated the need to study the effects of this virus on mental health. Various studies showed that COVID-19 could be a threat to people's mental health and physical health, yet the findings are still very limited. The purpose of the study was to fill an existing gap in the corresponding literature by analyzing Post Traumatic Stress Disorder (PTSD) symptoms, somatic complaints, depression, and anxiety in COVID-19 patients and studying their comorbidity to determine the impact of the virus on the patients' mental well- being.Methods: Patients diagnosed with COVID-19 took part in the study one month after their discharge from the hospital, accounting for 10% of all COVID-19 patients across Georgia during the research. PTSD Checklist (PCL-5) was used. Depression, somatic symptoms, and anxiety were assessed using the Patient Health Questionnaire (PHQ).Results: The results have shown that COVID-19, as a traumatic event, presents an association with PTSD, depression, anxiety, and somatic complaints. A high prevalence of depression (38,6%), anxiety (34,9%), and somatic symptoms (47%) was displayed. The overall indirect effect of PTSD on somatic symptoms was significant through depression and anxiety: 0.16, 95% CI [0.08, 0.26]. According to the report, the indirect effect of PTSD on somatic symptoms of depression was 0.12, 95% CI [0.05, 0.20].Conclusion: The study presents important findings on the relations between COVID-19 and patients mental health. Somatic complaints, depression, anxiety, and PTSD symptoms were prevalent in participants even after a month since they had COVID-19. Correlations between somatic complaints, anxiety, depression, and PTSD were also demonstrated. Even though there are various limitations to this study, how COVID-19 could affect mental health warrants further, more detailed research, which is necessary.Stress-related psychiatric disorders across the life spa

Thermal Analysis of Whole Bacterial Cells Exposed to Potassium Permanganate Using Differential Scanning Calorimetry: a Biphasic Dose-Dependent Response to Stress

Differential scanning calorimetry (DSC) was applied to estimate the impact of the toxic oxidant potassium permanganate (PM) on the intracellular structural and functional alterations at whole cell level using soil bacteria Arthrobacter oxydans as a model culture. Differential scanning calorimetry (DSC) was applied in order to estimate the impact of the toxic oxidant potassium permanganate (PM) on the intracellular structural and functional alterations at the whole cell level using the soil bacteria Arthrobacter oxydans as a model culture. We compared the total melting heat and the temperature of DNA-protein complex (DNP) melting at the PM application prior to the calorimetry measurement and after 24-h exposure at the concentration range 0.02–1.4 mM. The initial oxidative effect caused changes in the pattern of the whole cell melting spectra (mainly at the temperature range 56–78°C), the decrease of Tmax °C DNP melting, and did not influence significantly the total heat of bacterial melting at different concentrations of PM. The prolonged effect of permanganate up to 24 h was characterized by a biphasic dose-dependent response to stress estimated by the DSC technique and the colony-forming assay. The low doses of PM (0.02 and 0.2 mM) stimulated cell proliferation, and increased the total whole cell melting heat and the temperature of DNP melting. The toxic effect of PM up to 0.04 mM reduced cell viability, changed the character of multipeaked thermograms, and lowered the total melting heat and the temperature of DNP melting in a concentration-dependent manner. This study presents the DSC method for evaluating and monitoring the effects of exposure to potential human and environmental toxicants