Thermodynamic and kinetic basis for recognition and repair of 8-oxoguanine in DNA by human 8-oxoguanine-DNA glycosylase

We have used a stepwise increase in ligand complexity approach to estimate the relative contributions of the nucleotide units of DNA containing 7,8-dihydro-8-oxoguanine (oxoG) to its total affinity for human 8-oxoguanine DNA glycosylase (OGG1) and construct thermodynamic models of the enzyme interaction with cognate and non-cognate DNA. Non-specific OGG1 interactions with 10–13 nt pairs within its DNA-binding cleft provides approximately 5 orders of magnitude of its affinity for DNA (ΔG° approximately −6.7 kcal/mol). The relative contribution of the oxoG unit of DNA (ΔG° approximately −3.3 kcal/mol) together with other specific interactions (ΔG° approximately −0.7 kcal/mol) provide approximately 3 orders of magnitude of the affinity. Formation of the Michaelis complex of OGG1 with the cognate DNA cannot account for the major part of the enzyme specificity, which lies in the kcat term instead; the rate increases by 6–7 orders of magnitude for cognate DNA as compared with non-cognate one. The kcat values for substrates of different sequences correlate with the DNA twist, while the KM values correlate with ΔG° of the DNA fragments surrounding the lesion (position from −6 to +6). The functions for predicting the KM and kcat values for different sequences containing oxoG were found

Instructional Design of an Integrative Online Business English Course for Master’s Students of a Technical University

The article deals with the instructional design of an integrative Business English course for master’s students of a technical university (a case study of the Saint Petersburg Mining University) for blended and/or flexible learning. The main goal is to design a course that can be used as a full-fledged online course in asynchronous learning and is at the same time adjustable to the existing offline Business English course. The research uses methods such as observation, focus groups, surveying, empirical research and analytical and descriptive methods. The authors see a solution in a special instructional design based on the integration of traditional teaching approaches in offline learning, information technology and elements of infotainment and edutainment. The article presents the results of the target audience analysis and the needs analysis, outlines the structure of the course, specifies approaches to enhance motivation in master’s students and presents an integrative system of assessment and evaluation of the learners’ knowledge and skills. The key features of the instructional design of the Business English course suggested include exposure to professional scenarios, learners’ reflection, multiple instruments encouraging learners’ cognitive activity and performance and an opportunity to apply their knowledge to actual performance rather than summative assessment

General Haemodynamics, Aerobic Potential and Strategy for Adaptation of Students to Team Sports

Differentiated impact of team sports (basketball, indoor soccer, handball) on general haemodynamics and aerobic potential of students who specialize in technical subjects is detected only on the fourth year of studies in the institute of higher education. Those who play basketball and indoor soccer have shown increase of stroke and minute volume of blood indices, pumping and contractile function of the heart, oxygenation of blood and oxygen delivery to tissues, aerobic energy supply and balance of sympathetic and parasympathetic activity of the nervous regulation mechanism of the circulatory system. Those who play handball have shown these indices statistically decreased. On the whole playing basketball and indoor soccer optimizes the strategy for adaptation of students to the studying process, but playing handball does the opposite thing. The leading factor for adaptation of students is: those who play basketball have increase of minute blood volume which stipulates velocity of the system blood circulation and well-timed oxygen delivery to tissues; those who play indoor soccer have increase of power and velocity of contractile function of the heart; those who play handball have increase of resistance of thorax to the system blood flow which minimizes contractile function of the heart, blood oxygen saturation and delivery of oxygen to tissues