Cross-Talk between the Cellular Redox State and the Circadian System in Neurospora

The circadian system is composed of a number of feedback loops, and multiple feedback loops in the form of oscillators help to maintain stable rhythms. The filamentous fungus Neurospora crassa exhibits a circadian rhythm during asexual spore formation (conidiation banding) and has a major feedback loop that includes the FREQUENCY (FRQ)/WHITE COLLAR (WC) -1 and -2 oscillator (FWO). A mutation in superoxide dismutase (sod)-1, an antioxidant gene, causes a robust and stable circadian rhythm compared with that of wild-type (Wt). However, the mechanisms underlying the functions of reactive oxygen species (ROS) remain unknown. Here, we show that cellular ROS concentrations change in a circadian manner (ROS oscillation), and the amplitudes of ROS oscillation increase with each cycle and then become steady (ROS homeostasis). The ROS oscillation and homeostasis are produced by the ROS-destroying catalases (CATs) and ROS-generating NADPH oxidase (NOX). cat-1 is also induced by illumination, and it reduces ROS levels. Although ROS oscillation persists in the absence of frq, wc-1 or wc-2, its homeostasis is altered. Furthermore, genetic and biochemical evidence reveals that ROS concentration regulates the transcriptional function of WCC and a higher ROS concentration enhances conidiation banding. These findings suggest that the circadian system engages in cross-talk with the cellular redox state via ROS-regulatory factors

Reconciling evolution: evidence from a biology and theology course

Abstract Background Many individuals reject evolutionary theory due to a perceived conflict with their religious beliefs. To bridge this gap, educators have attempted different approaches including approaching evolution rejection as a consequence of deficit thinking and teaching students the nature of science (including the scientific process and peer review process as well as questions that science can and cannot answer).Teaching the nature of science has shown promising gains in the acceptance of evolution, although acceptance rates remain low. We propose a further approach: the use of a reconciliatory model designed to help students accept evolution within the framework of their religious beliefs. We tested this approach in both biology and theology classrooms at a Nazarene-affiliated university. Both professors approached the subject in a reconciliatory fashion. Results This study found that by utilizing a reconciliatory approach, the students in both classrooms saw significant gains in evolution acceptance, with gains being greatest in the biology classroom. In addition, we saw no decrease in student religiosity. Conclusions Implications of this are discussed. The results of this study confirm the effectiveness of a reconciliatory model, which opens several avenues for further research. </jats:sec

Fluorescence of commercial Pluronic F127 samples: Temperature-dependent micellization

We present a novel approach of using the butylated hydroxytoluene (BHT) antioxidant found in commercial Pluronic F127 samples as a marker of polymer aggregation. The BHT marker was compared to the pyrene dye and static light scattering methods as a way to measure the critical micelle concentration (CMC) and critical micelle temperature (CMT). The n ¿ p* transitions of BHT are sensitive to the microenvironment as demonstrated by plotting the fractional intensities of its excitation (¿280 nm) and emission (¿325 nm) peaks. BHT is more sensitive to changes in temperature than concentration. The partition coefficient increases ¿40-fold for pyrene compared to ¿2-fold for BHT when the temperature is increased from 25 to 37 °C. CMT values determined using the BHT fluorescence decrease with increasing F127 concentration. Our results show that BHT can be used as a reliable marker of changes in the microenvironment of Pluronic F127