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Oocyte maturation is a process wherein an oocyte arrested at prophase of meiosis I resumes meiosis to become a fertilizable egg. In starfish ovaries, a hormone released from follicle cells activates the oocytes, resulting in an increase in their intracellular pH (pHi), which is required for spindle assembly. [https://www.selleckchem.com/products/nec-1s-7-cl-o-nec1.html Selleck Necrostatin 2] Herein, we describe a protocol for pHi measurement in living oocytes microinjected with the pH-sensitive dye BCECF. For in vivo BCECF calibration, we treated oocytes with artificial seawater containing CH3COONH4 to clamp pHi, injected pH-standard solutions, and converted the BCECF fluorescence intensity ratios to pHi values. Of note, if the actual pHi is higher or lower than the known pH of injected standard solutions, the BCECF fluorescence intensity ratio will decrease or increase, respectively. On the other hand, the pH of the injected solution displaying no change in fluorescence intensity should be considered the actual pHi. These methods for pHi calibration and clamping are simple and reproducible.The study of food addiction comprises 3 hallmarks that include the persistence to response without an outcome, the strong motivation for palatable food, and the loss of inhibitory control over food intake that leads to compulsive behavior in addicted individuals. The complex multifactorial nature of this disorder and the unknown neurobiological mechanistic correlation explains the lack of effective treatments. Our operant conditioning model allows deciphering why some individuals are vulnerable and develop food addiction while others are resilient and do not. It is a translational approach since it is based on the Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM-5) and the Yale Food Addiction Scale (YFAS 2.0). This model allows to evaluate the addiction criteria in 2 time-points at an early and a late period by grouping them into 1) persistence to response during a period of non-availability of food, 2) motivation for food with a progressive ratio, and 3) compulsivity when the reward is n circuit level. We can study using this protocol if modifying the excitability of a specific brain network confers resilience or vulnerability to developing food addiction. Understanding these neurobiological mechanisms is expected to help to find novel and efficient interventions to battle food addiction.In this protocol, we describe our methods to isolate crypts from patients' biopsy samples and to culture human intestinal stem cells as it's called "organoid." Beyond that, we describe how to dissociate organoids cells into single cells for single-cell analysis as a further application. This protocol should provide investigators sufficient tools to generate human organoids from biopsy samples and to accomplish a stable in-vitro assay system.Investigation of bacterial gene regulation upon environmental changes is still a challenging task. For example, Vibrio cholerae, a pathogen of the human gastrointestinal tract, faces diverse transient conditions in different compartments upon oral ingestion. Genetic reporter systems have been demonstrated to be extremely powerful tools to unravel gene regulation events in complex conditions, but so far focused mainly on gene induction. Herein, we describe the TetR-controlled recombination-based in vivo expression technology TRIVET, which allows detection of gene silencing events. TRIVET resembles a modified variant of the in vivo expression technology (IVET) as well as recombination-based in vivo expression technology (RIVET), which were used to identify conditional gene induction in several bacteria during host colonization. Like its predecessors, TRIVET is a single cell based reporter system, which allows the analysis of bacterial gene repression in a spatiotemporal manner via phenotypical changes in the reas well as a quantification of the conditional repression of a gene of interest. Although the current protocol is established for gene repression during host colonization, it can likely be adapted to study gene silencing under various conditions faced by a bacterium.Genetically encoded biosensors are powerful tools for quantitative visualization of ions and metabolites in vivo. Design and optimization of such biosensors typically require analyses of large numbers of variants. Sensor properties determined in vitro such as substrate specificity, affinity, response range, dynamic range, and signal-to-noise ratio are important for evaluating in vivo data. This protocol provides a robust methodology for in vitro binding assays of newly designed sensors. Here we present a detailed protocol for purification and in vitro characterization of genetically encoded sensors, exemplified for the His affinity-tagged GO-(Green-Orange) MatryoshCaMP6s calcium sensor. GO-Matryoshka sensors are based on single-step insertion of a cassette containing two nested fluorescent proteins, circularly permutated fluorescent green FP (cpGFP) and Large Stoke Shift LSSmOrange, within the binding protein of interest, producing ratiometric sensors that exploit the analyte-triggered change in fluorescence of a cpGFP.We describe a protocol for preparing acute brain slices which can produce robust hippocampal sharp wave-ripples (SWRs) in vitro. The protocol is optimized for its simplicity and reliability for the preparation of solutions, slicing, and recovery incubation. Most slices in almost every mouse prepared though the protocol expressed vigorous spontaneous SWRs for ~24 h, compared to the 20-30% viability from "standard" low sodium slicing protocols. SWRs are spontaneous neuronal activity in the hippocampus and are essential for consolidation of episodic memory. Brain slices reliably expressing SWRs are useful for studying memory impairment and brain degeneration diseases in ex vivo experiments. Spontaneous expression of SWRs is sensitive to conditions of slicing and perfusion/oxygenation during recording. The amplitude and abundance of SWRs are often used as a biomarker for viable slices. Key improvements include fast circulation, a long recovery period (3-6 h) after slicing, and allowing tissue to recover at 32 °C in a well perfused incubation chamber.