In chemical synapses an action potential depolarizes presynaptic membrane and opens voltage-gated calcium channels after which calcium influxes to the cell. Studying of calcium influx in nerve ending is an important step in understanding of signal transmission in neuromuscular junction. Our laboratory uses a method for recording of calcium transient in a photometric setup, which involves recording series of images in order to obtain a signal. The image processing technique currently in use involves making decisions based on our experience in identifying the area of registration of a useful signal. The idea of this work is creating of algorithm for analyzing experimental data which allows minimal participation of the experimenter. The idea based on the use of computer vision methods (OpenCV), provides the correct detection of nerve endings on experimental fluorescence images. The image processing algorithm includes the following steps: noise reduction; morphological transformations erosion and dilatation; a composite set of masks for different time points and their subsequent combination into one mask using image binarization by Otsu. The result of this work is an algorithm used to process experimental images, providing a strictly defined reproducible procedure, devoided of inaccuracy, introduced into experimental image processing.
Keywords: synapse, neuromuscular junction, computer vision, calcium, photometric setup, fluorescent dye
The manuscript describes the design of a simple LED illuminator for fluorescence microscopy of biological objects. As the light source, high-brightness semiconductor diodes were chosen that provide stable low-noise light. This distinguishes them from traditional light sources, such as mercury lamps. The presented light source can be used to record low-amplitude fluorescent signals in studies of excitable cells performed using calcium or potential-sensitive dyes. The illuminator is made of inexpensive, easily accessible components.
Keywords: high-brightness LEDs, illuminator, fluorescence, microscopy