Microglia sense and suppress epileptic neuronal hyperexcitability.

Microglia are the resident immune cells of the central nervous system, undertaking surveillance role and reacting to brain homeostasis and neurological diseases. Recent studies indicate that microglia modulate epilepsy-induced neuronal activities, however, the mechanisms underlying microglia-neuron communication in epilepsy are still unclear. Here we report that epileptic neuronal hyperexcitability activates microglia and drives microglial ATP/ADP hydrolyzing ectoenzyme CD39 (encoded by Entpd1) expression via recruiting the cAMP responsive element binding protein (CREB)-regulated transcription coactivator-1 (CRTC1) from cytoplasm to the nucleus and binding to CREB. Activated microglia in turn suppress epileptic neuronal hyperexcitability in a CD39 dependent manner. Disrupting microglial CREB/CRTC1 signaling, however, decreases CD39 expression and diminishes the inhibitory effect of microglia on epileptic neuronal hyperexcitability. Overall, our findings reveal CD39-dependent control of epileptic neuronal hyperexcitability by microglia is through an excitation-transcription coupling mechanism.

Effects of temporary rearing with organic selenium on the muscle flavor and texture properties of largemouth bass (Micropterus salmonides).

In this study, the influences of organic selenium (Se, 0.002 mg/L) on the muscle flavor and texture properties of Micropterus salmonides under fasting temporary rearing (8 weeks) was investigated. Electronic nose and headspace solid-phase microextraction-gas chromatography-mass spectrometry analysis suggested that organic Se regulated the types and contents of volatile compounds, especially aldehydes and ketones, which were increased in the early temporary rearing but decreased in the late stage. Organic Se significantly increased the content of 5'-inosine monophosphate by approximately 15 % (p < 0.05), and decreased the content of hypoxanthine and hypoxanthine ribonucleoside by more than 20 % (p < 0.05). After the 8th temporary rearing week, muscle hardness and springiness increased by at least 10 % (p < 0.01), resilience and gumminess improved by at least 18 % (p < 0.05) and 5.9 % (p < 0.05), respectively. In conclusion, organic Se ameliorates the flesh quality of M. salmonides during long-term temporary rearing.

Brackish water improves the taste quality in meat of adult male Eriocheir sinensis during the postharvest temporary rearing.

We investigated the effect of temporary rearing in brackish water on the taste quality in meat of crab cooked. The main salinity-responsive factors included 5'-nucleotides and free amino acids (FAAs) in crab meat that were identified using tri-step infrared spectroscopy. Compared to the fresh water group, the contents of 5'-adenosine monophosphate and 5'-inosine monophosphate in the brackish water group significantly increased in the 2nd week and decreased in the 6th week, respectively. The contribution ratio of umami FAAs increased from 8.1 to 13.5% in the 4th week in the brackish water group, showing maximum value of equivalent umami concentration. Moreover, Ca2+ and Cl- contents significantly increased in the 4th and 6th weeks, respectively (P < 0.05). Infrared spectroscopy was an effective method to identify the taste components. With respect to the taste quality, four weeks were determined as the best period for temporary rearing of the crab in brackish water.

Effect of nanocomposite-based packaging on microstructure and energy metabolism of Agaricus bisporus.

Rapid deterioration of postharvest Agaricus bisporus is a serious problem. Measures to improve the shelf-life are of great importance. Therefore, we used a nanocomposite-based packaging material (Nano-PM) containing nano-TiO2, nano-SiO2, nano-Ag and attapulgite to study its effect on microstructure and energy metabolism of A. bisporus. Nano-PM reduced the oxidation of lipids and proteins by activating antioxidant enzyme activities and inhibiting the accumulation of ROS, thereby maintained high level of energy status. Meanwhile, ATP content and energy charge of A. bisporus in Nano-PM increased through the energy metabolism system. This was attributed to the lower respiration rate and higher mitochondrial respiratory enzyme activities. These results indicated that Nano-PM could maintain the dense and intact microstructure of A. bisporus thus improve its shelf-life.

Hydrophilic interaction liquid chromatography coupled with quadrupole-orbitrap ultra high resolution mass spectrometry to quantitate nucleobases, nucleosides, and nucleotides during white tea withering process.

Nucleotides, nucleosides, and nucleobases are important bioactive compounds. Recent studies suggested that they possess taste activity. However, it remains unknown about their presence in white tea and how they change during white tea manufacture. Here, we first established method based on hydrophilic interaction liquid chromatography coupled with quadrupole-orbitrap ultra high resolution mass spectrometry (HILIC-Quadrupole-Orbitrap-UHRMS) platform, then applied it to study the dynamic changes of nucleotides, nucleosides, and nucleobases during white tea withering process. Five compounds, including adenosine 5'-monophosphate monohydrate (AMP), guanosine 5'-monophosphate disodium salt hydrate (GMP), adenosine, cytidine, thymine and uracil, were detected from withering samples. They showed a general decline trend during white tea withering process, however, considerable amount of them was retained after withering for 48 h except adenosine which was below detection limit after withering for 21 h. This study provided a complete picture about nucleotides, nucleosides and nucleobases changes during white tea withering process.