Resolving the contributions of the membrane-bound and periplasmic nitrate reductase systems to nitric oxide and nitrous oxide production in Salmonella enterica serovar Typhimurium

The production of cytotoxic nitric oxide (NO) and conversion into the neuropharmacological agent and potent greenhouse gas nitrous oxide (N2O) is linked with anoxic nitrate catabolism by Salmonella enterica serovar Typhimurium. Salmonella can synthesize two types of nitrate reductase: a membrane-bound form (Nar) and a periplasmic form (Nap). Nitrate catabolism was studied under nitrate-rich and nitrate-limited conditions in chemostat cultures following transition from oxic to anoxic conditions. Intracellular NO production was reported qualitatively by assessing transcription of the NO-regulated genes encoding flavohaemoglobin (Hmp), flavorubredoxin (NorV) and hybrid cluster protein (Hcp). A more quantitative analysis of the extent of NO formation was gained by measuring production of N2O, the end-product of anoxic NO-detoxification. Under nitrate-rich conditions, the nar, nap, hmp, norV and hcp genes were all induced following transition from the oxic to anoxic state, and 20% of nitrate consumed in steady-state was released as N2O when nitrite had accumulated to millimolar levels. The kinetics of nitrate consumption, nitrite accumulation and N2O production were similar to those of wild-type in nitrate-sufficient cultures of a nap mutant. In contrast, in a narG mutant, the steady-state rate of N2O production was ~30-fold lower than that of the wild-type. Under nitrate-limited conditions, nap, but not nar, was up-regulated following transition from oxic to anoxic metabolism and very little N2O production was observed. Thus a combination of nitrate-sufficiency, nitrite accumulation and an active Nar-type nitrate reductase leads to NO and thence N2O production, and this can account for up to 20% of the nitrate catabolized

The transcriptional repressor protein NsrR senses nitric oxide directly via a [2Fe-2S] cluster

The regulatory protein NsrR, a member of the Rrf2 family of transcription repressors, is specifically dedicated to sensing nitric oxide (NO) in a variety of pathogenic and non-pathogenic bacteria. It has been proposed that NO directly modulates NsrR activity by interacting with a predicted [Fe-S] cluster in the NsrR protein, but no experimental evidence has been published to support this hypothesis. Here we report the purification of NsrR from the obligate aerobe Streptomyces coelicolor. We demonstrate using UV-visible, near UV CD and EPR spectroscopy that the protein contains an NO-sensitive [2Fe-2S] cluster when purified from E. coli. Upon exposure of NsrR to NO, the cluster is nitrosylated, which results in the loss of DNA binding activity as detected by bandshift assays. Removal of the [2Fe-2S] cluster to generate apo-NsrR also resulted in loss of DNA binding activity. This is the first demonstration that NsrR contains an NO-sensitive [2Fe-2S] cluster that is required for DNA binding activity

Biochemical properties of Paracoccus denitrificans FnrP:Reactions with molecular oxygen and nitric oxide

In Paracoccus denitrificans, three CRP/FNR family regulatory proteins, NarR, NnrR and FnrP, control the switch between aerobic and anaerobic (denitrification) respiration. FnrP is a [4Fe-4S] cluster containing homologue of the archetypal O2 sensor FNR from E. coli and accordingly regulates genes encoding aerobic and anaerobic respiratory enzymes in response to O2, and also NO, availability. Here we show that FnrP undergoes O2-driven [4Fe-4S] to [2Fe-2S] cluster conversion that involves up to 2 O2 per cluster, with significant oxidation of released cluster sulfide to sulfane observed at higher O2 concentrations. The rate of the cluster reaction was found to be ~6-fold lower than that of E. coli FNR, suggesting that FnrP can remain transcriptionally active under microaerobic conditions. This is consistent with a role for FnrP in activating expression of the high O2 affinity cytochrome c oxidase under microaerobic conditions. Cluster conversion resulted in dissociation of the transcriptionally active FnrP dimer into monomers. Therefore, along with E. coli FNR, FnrP belongs to the subset of FNR proteins in which cluster type is correlated with association state. Interestingly, two key charged residues, Arg140 and Asp154, that have been shown to play key roles in the monomer-dimer equilibrium in E. coli FNR are not conserved in FnrP, indicating that different protomer interactions are important for this equilibrium. Finally, the FnrP [4Fe-4S] cluster is shown to undergo reaction with multiple NO molecules, resulting in iron nitrosyl species and dissociation into monomers

DIVERGENT REACTIONS OF ESTERS OF ACYLPYRUVIC ACIDS WITH o-PHENYLENEDIAMINE

This work was supported by the Ministry of Science and Higher Education of the Russian Federation (FSNF-2020-0008), Russian Foundation for Basic Research (project no. 20-43-596008) and the Government of Perm Krai. Antimicrobial screening was performed by CO-ADD (The Community for Antimicrobial Drug Discovery), funded by the Wellcome Trust (UK) and The University of Queensland (Australia)

Ecological awarenessof students (case study of attitudes towards the impact of the fashion industry on the environment)

Environmental regulation becomes an indispensable activity for preserving human life. The negative impact of the fashion industry on the environment is growing. The article presents the results of an empirical study conducted by the authors using the survey method in Spring 2023. The aim of the research is to determine the attitudes of contemporary Russian students to the impact of the fashion industry on the environment. The subject of the research are full-time students of Russian universities. The article considers the following issues: the involvement of young people in the consumer behavior of fashion industry products; the orientation of young people on the environmental promises of fashion brands when choosing goods; the consideration of price factors when deciding to buy fashion products; young people’s ideas about environmental and non-environmental fashion brands; awareness of the harmful effects of the fashion industry on the environment; the question of young people’s willingness to change their consumption patterns in order to reduce the negative impact of the fashion industry on the environment; the need to follow social practices related to environmental principles in the context of consumption of fashion industry products in everyday life. The conclusion has been made that it is necessary to develop communication campaigns aimed at the target audience of young people, which will highlight the issues of eco-friendly practices, environmentally friendly behavior, disclose the consequences of the negative impact of the fashion industry on the environment

A study of young people’s attitudes towards the impact of the fashion industry on the environment

This article presents the results of an empirical study aimed at studying young people’s attitudes to the impact of the fashion industry on the environment. The survey is used as a research method. The study was conducted in the spring of 2023. As a result of the study, a high degree of awareness of young people about the negative impact of the fashion industry on the environment was revealed; the attitude of young people to the manifestations of the fashion industry was revealed; the willingness of young people to change their consumer practices in the fashion industry was determined; aspects of the behavior of young people associated with following eco-friendly principles (higher awareness when consuming industry goods fashion; more rare purchases of fashion industry products; rejection of genuine leather and fur in clothing; reduction of consumption of various goods; the purchase of goods in eco-friendly/recyclable packaging; focus on the purchase of eco-friendly products; the delivery of personal belongings for recycling; the use of second-hand goods); the positive attitude of young people to the types of activities that can be carried out by companies in the fashion industry aimed at solving environmental problems has been revealed

Students’ attitudes to social advertising: results of a study

The article presents the results of an empirical study aimed at studying the attitude of students to social advertising.   The object of the empirical study is student youth.   The subject of the study is the students’ attitude to the placement channels and modern technologies for attracting attention to social advertising.   The topic of social advertising was chosen for the study – advertising aimed at helping homeless animals. The study was conducted in spring 2023 using a survey method. The study identified young people’s readiness to be involved in solving social problems; the work showed young people’s attitudes to channels of social advertising; this research determined the attitudes to the emotional component of social advertising and revealed attitude to new ways of attracting attention that are used in contemporary social advertising. The study results indicate that, firstly, most young people are ready to help shelters and foundations that support to homeless animals, however, young people are not ready to make an effort to find the necessary information; secondly, young people do not always notice social advertising, despite the fact that they actively use different media channels; thirdly, according to respondents, the most effective social advertising contains in the verbal or visual series direct encouragement to the target action; fourthly, in order to increase the level of involuntary attention of target groups to social advertising, it is necessary to use new techniques of visual impact on the audience using digital technologies. In conclusion of this article, findings and recommendations are formulated which can be applied in the development of social advertising campaigns

Morfofunzionale sperimentali principi base trattamento di pulpite

Riassumendo i risultati della ricerca si può concludere che i processi di carie superficiali di cambiamento nella polpa sono reversibili e possono scomparire al trattamento terapeutico normale della carie dentale. Decadimento medio caratterizzata dallo sviluppo di reazioni di adattamento della polpa e cambiamenti condizionale reversibili, tattiche terapeutiche in cui devono essere affrontati nel caso specifico con prove cliniche. Con carie profonda sviluppano cambiamenti irreversibili, che possono essere eliminati con l'aiuto di pulpotomia. Carie profonda con perforazione della camera pulpare è caratterizzata da cambiamenti irreversibili in tutte le parti della camera di polpa, che è un'indicazione per pulpectomia

Philosophy in the context of higher medical education

У статті обґрунтовано значення філософії у процесі світоглядного й професійного формування майбутніх лікарів. Розкрито важливі аспекти її взаємодії з медициною та доведено, що філософія є методологічним фундаментом медичного знання. Тому у процесі професійної підготовки студентів-медиків повинні бути знайдені нові підходи та важелі для формування у них позитивного ставлення до вивчення філософії, а також повинні змінитися існуючі стереотипи в суспільстві.; The philosophy remains the only comprehensive subject that students consider unnecessary in current educational environment. Mastering the basics of philosophical knowledge helps student to become professional expert with the ability to think widely and deeply and act independently. The philosophy promotes creative thinking, helps in the study of clinical disciplines, serves as the basis for perception of new ideas, and uses the acquired knowledge to solve the specific tasks. Consequently, new approaches and mechanisms for forming a positive attitude to the study of philosophy, as well as the need to change existing stereotypes in the society should be found in the process of training of medical students