Mice Null for Calsequestrin 1 Exhibit Deficits in Functional Performance and Sarcoplasmic Reticulum Calcium Handling

In skeletal muscle, the release of calcium (Ca2+) by ryanodine sensitive sarcoplasmic reticulum (SR) Ca2+ release channels (i.e., ryanodine receptors; RyR1s) is the primary determinant of contractile filament activation. Much attention has been focused on calsequestrin (CASQ1) and its role in SR Ca2+ buffering as well as its potential for modulating RyR1, the L-type Ca2+ channel (dihydropyridine receptor, DHPR) and other sarcolemmal channels through sensing luminal [Ca2+]. The genetic ablation of CASQ1 expression results in significant alterations in SR Ca2+ content and SR Ca2+ release especially during prolonged activation. While these findings predict a significant loss-of-function phenotype in vivo, little information on functional status of CASQ1 null mice is available. We examined fast muscle in vivo and in vitro and identified significant deficits in functional performance that indicate an inability to sustain contractile activation. In single CASQ1 null skeletal myofibers we demonstrate a decrease in voltage dependent RyR Ca2+ release with single action potentials and a collapse of the Ca2+ release with repetitive trains. Under voltage clamp, SR Ca2+ release flux and total SR Ca2+ release are significantly reduced in CASQ1 null myofibers. The decrease in peak Ca2+ release flux appears to be solely due to elimination of the slowly decaying component of SR Ca2+ release, whereas the rapidly decaying component of SR Ca2+ release is not altered in either amplitude or time course in CASQ1 null fibers. Finally, intra-SR [Ca2+] during ligand and voltage activation of RyR1 revealed a significant decrease in the SR[Ca2+]free in intact CASQ1 null fibers and a increase in the release and uptake kinetics consistent with a depletion of intra-SR Ca2+ buffering capacity. Taken together we have revealed that the genetic ablation of CASQ1 expression results in significant functional deficits consistent with a decrease in the slowly decaying component of SR Ca2+ release

The utilisation of e-learning facilities in theeducational delivery system of Nigeria: astudy of M-University

In spite of the constant innovative approaches adopted by teachers in westernworld, traditional approaches to teaching and assessments in Nigeria tertiaryinstitutions have constantly been practiced. Most institutions are not able to fullyutilize e-learning or get full advantages of it. This failure has hindered most teachersin using innovative teaching methodologies in delivering their lectures, andundertake rigorous research works. The study examines adoption and utilisation of e-learning facilities by lecturers in Nigerian private tertiary institution. The studyadopted qualitative approach to investigate the adoption and utilisation of e-learning facilities by lecturers in a Nigerian private tertiary institution using 15 semi-structured interviews from the academic staff of M-University. Raw data gatheredwere analysed using data driven thematic approach (a similar approach to groundedtheory).The findings reveal that M-University’s e-learning facilities are adequate andaccessible to users, and most teachers are comfortable with utilisation of variousfacilities during classes compared to most public tertiary institutions although, theutilisation has not been maximised. However, attitude of users, inadequate internetfacility, inadequate training of users affect the successful adoption. The studyrecommends that e-learning facilities should be constantly upgraded, and that M-University should train their staff continuously to meet the constant advancementsof the e-Learning facilities in order to maximize usag