This robust sound source representation leads to an invariance in perception vital for animals to interact effectively with their environment. Due to unique nonlinearities in the cochlea, sound representations early in the auditory system exhibit a large amount of variability as a function of stimulus intensity. In other words, changes in stimulus intensity, such as for sound sources at differing distances, create a unique challenge for the auditory system to encode sounds invariantly across the intensity dimension. This challenge and some strategies available to sensory systems to eliminate intensity as an encoding variable are discussed, with a special emphasis upon sound encoding.
(C) 2011 Elsevier Ltd. All rights reserved.”
“Aims:
The CX-6258 price aim of the work is to exploit the yeast pheromone system for controlled cell-cell communication and as an amplification circuit in technical applications, e.g. biosensors or sensor-actor systems.
Methods and Results:
As a proof of principle, we developed recombinant Saccharomyces cerevisiae cells that express enhanced green fluorescent protein (EGFP) in response to different concentrations of the alpha (alpha)-factor mating pheromone. A respective reporter construct allowing the pheromone-driven expression of EGFP was transformed into the S. cerevisiae strains BY4741 and BY4741 bar1 Delta. Upon addition of synthetic alpha-factor, the fluorescence strongly
increases after 4 h. Furthermore, cells with constitutive alpha-factor expression were able to induce the expression of EGFP in co-cultivation with sensor cells only if both cell types were deleted for the gene BAR1, encoding selleck compound alpha-factor protease. For technical applications, the immobilization of functionalized
cells may be beneficial. We show that pheromone-induced expression of EGFP is effective in alginate-immobilized cells.
Conclusions:
Based on S. cerevisiae alpha-factor, we developed a controlled cell-cell communication system and amplification circuit for pheromone-driven expression of a target protein. The system is effective both in suspension and after cell immobilization.
Significance and Impact of the Study:
The developed set of recombinant yeast strains is the basis to apply the yeast pheromone system for signal production and amplification in biosensors or sensor-actor systems.”
“Using their biological Liproxstatin-1 ic50 sonar, bats estimate distance to avoid obstacles and capture moving prey. The primary distance cue is the delay between the bat’s emitted echolocation pulse and the return of an echo. The mustached bat’s auditory midbrain (inferior colliculus, IC) is crucial to the analysis of pulse-echo delay. IC neurons are selective for certain delays between frequency modulated (FM) elements of the pulse and echo. One role of the IC is to create these “”delay-tuned”", “”FM-FM”" response properties through a series of spectra-temporal integrative interactions.