Synchronization of Circadian Per2 Rhythms and HSF1-BMAL1:CLOCK Interaction in Mouse Fibroblasts after Short-Term Heat Shock Pulse

Circadian rhythms are the general physiological processes of adaptation to daily environmental changes, such as the temperature cycle. A change in temperature is a resetting cue for mammalian circadian oscillators, which are possibly regulated by the heat shock (HS) pathway. The HS response (HSR) is a universal process that provides protection against stressful conditions, which promote protein-denaturation. Heat shock factor 1 (HSF1) is essential for HSR. In the study presented here, we investigated whether a short-term HS pulse can reset circadian rhythms. Circadian Per2 rhythm and HSF1-mediated gene expression were monitored by a real-time bioluminescence assay for mPer2 promoter-driven luciferase and HS element (HSE; HSF1-binding site)-driven luciferase activity, respectively. By an optimal duration HS pulse (43°C for approximately 30 minutes), circadian Per2 rhythm was observed in the whole mouse fibroblast culture, probably indicating the synchronization of the phases of each cell. This rhythm was preceded by an acute elevation in mPer2 and HSF1-mediated gene expression. Mutations in the two predicted HSE sites adjacent (one of them proximally) to the E-box in the mPer2 promoter dramatically abolished circadian mPer2 rhythm. Circadian Per2 gene/protein expression was not observed in HSF1-deficient cells. These findings demonstrate that HSF1 is essential to the synchronization of circadian rhythms by the HS pulse. Importantly, the interaction between HSF1 and BMAL1:CLOCK heterodimer, a central circadian transcription factor, was observed after the HS pulse. These findings reveal that even a short-term HS pulse can reset circadian rhythms and cause the HSF1-BMAL1:CLOCK interaction, suggesting the pivotal role of crosstalk between the mammalian circadian and HSR systems

Screening and monitoring microbial xenobiotics’ biodegradation by rapid, inexpensive and easy to perform microplate UV-absorbance measurements

Background Evaluation of xenobiotics biodegradation potential, shown here for benzotriazoles (corrosion inhibitors) and sulfamethoxazole (sulfonamide antibiotic) by microbial communities and/or pure cultures normally requires time intensive and money consuming LC/GC methods that are, in case of laboratory setups, not always needed. Results The usage of high concentrations to apply a high selective pressure on the microbial communities/pure cultures in laboratory setups, a simple UV-absorbance measurement (UV-AM) was developed and validated for screening a large number of setups, requiring almost no preparation and significantly less time and money compared to LC/GC methods. This rapid and easy to use method was evaluated by comparing its measured values to LC-UV and GC-MS/MS results. Furthermore, its application for monitoring and screening unknown activated sludge communities (ASC) and mixed pure cultures has been tested and approved to detect biodegradation of benzotriazole (BTri), 4- and 5-tolyltriazole (4-TTri, 5-TTri) as well as SMX. Conclusions In laboratory setups, xenobiotics concentrations above 1.0 mg L-1 without any enrichment or preparation could be detected after optimization of the method. As UV-AM does not require much preparatory work and can be conducted in 96 or even 384 well plate formats, the number of possible parallel setups and screening efficiency was significantly increased while analytic and laboratory costs were reduced to a minimum

Multiperiod Multi Traveling Salesmen Problem Considering Time Window Constraints with an Application to a Real World Case

WOS: 000473179100001This study arises from a real world problem. In the problem, a number of university representatives are required to visit a number of exam locations departing from a central location and returning back to the same location. Each location may be visited in one of four different periods; however these visits must be done in pre-specified time windows. Time windows may be different from location to location and across periods for the same location. The problem is modeled as a multi-period multi traveling salesmen problem with time window constraints. Earlier attempts to solve the resulting models using mixed integer linear programming approach proved to be ineffective. Hence two stochastic heuristic search techniques, based on simulated annealing (SA) and robust tabu search (RTS), are used. For this, a new solution representation and associated decoding and encoding mechanisms are developed. Proposed approaches are tested on various problem instances, and performance of the solution approaches are discussed. Finally, a real case is considered for which a method for obtaining travel distance and travel time matrices from Google Distance Matrix API is developed. The results obtained from the real case is also discussed and future research directions are provided.Anadolu University Scientific Research Projects Commission [1506F495]This study was supported by Anadolu University Scientific Research Projects Commission under the grant no: 1506F495. The author would like to thank the anonymous reviewers and the Editor-in-Chief for their helpful and constructive comments that greatly contributed to improving the final version of the paper