HMGB1 mediates synaptic loss and cognitive impairment in an animal model of sepsis-associated encephalopathy.

BACKGROUND: Microglial activation-mediated neuroinflammation is one of the essential pathogenic mechanisms of sepsis-associated encephalopathy (SAE). Mounting evidence suggests that high mobility group box-1 protein (HMGB1) plays a pivotal role in neuroinflammation and SAE, yet the mechanism by which HMGB1 induces cognitive impairment in SAE remains unclear. Therefore, this study aimed to investigate the mechanism of HMGB1 underlying cognitive impairment in SAE. METHODS: An SAE model was established by cecal ligation and puncture (CLP); animals in the sham group underwent cecum exposure alone without ligation and perforation. Mice in the inflachromene (ICM) group were continuously injected with ICM intraperitoneally at a daily dose of 10 mg/kg for 9 days starting 1 h before the CLP operation. The open field, novel object recognition, and Y maze tests were performed on days 14-18 after surgery to assess locomotor activity and cognitive function. HMGB1 secretion, the state of microglia, and neuronal activity were measured by immunofluorescence. Golgi staining was performed to detect changes in neuronal morphology and dendritic spine density. In vitro electrophysiology was performed to detect changes in long-term potentiation (LTP) in the CA1 of the hippocampus. In vivo electrophysiology was performed to detect the changes in neural oscillation of the hippocampus. RESULTS: CLP-induced cognitive impairment was accompanied by increased HMGB1 secretion and microglial activation. The phagocytic capacity of microglia was enhanced, resulting in aberrant pruning of excitatory synapses in the hippocampus. The loss of excitatory synapses reduced neuronal activity, impaired LTP, and decreased theta oscillation in the hippocampus. Inhibiting HMGB1 secretion by ICM treatment reversed these changes. CONCLUSIONS: HMGB1 induces microglial activation, aberrant synaptic pruning, and neuron dysfunction in an animal model of SAE, leading to cognitive impairment. These results suggest that HMGB1 might be a target for SAE treatment.

Purification and Characterization of a Thermo- and pH-Stable Laccase From the Litter-Decomposing Fungus Gymnopus luxurians and Laccase Mediator Systems for Dye Decolorization.

An extracellular laccase (GLL) was purified from fermentation broth of the litter-decomposing fungus Gymnopus luxurians by four chromatography steps, which resulted in a high specific activity of 118.82 U/mg, purification fold of 41.22, and recovery rate of 42.05%. It is a monomeric protein with a molecular weight of 64 kDa and N-terminal amino acid sequence of AIGPV TDLHI, suggesting that GLL is a typical fungal laccase. GLL demonstrated an optimum temperature range of 55°C-65°C and an optimum pH 2.2 toward 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). It displayed considerably high thermostability and pH stability with about 63% activity retained after 24 h at 50°C, and 86% activity retained after 24 h at pH 2.2, respectively. GLL was significantly enhanced in the presence of K+, Na+, and Mg2+ ions. It demonstrated K m of 539 µM and k cat /K m of 140 mM-1⋅s-1 toward ABTS at pH 2.2 and 37°C. Acetosyringone (AS) and syringaldehyde (SA) were the optimal mediators of GLL (0.4 U/ml) for dye decolorization with decolorization rates of about 60%-90% toward 11 of the 14 synthetic dyes. The optimum reaction conditions were determined to be mediator concentration of 0.1 mM, temperature range of 25°C -60°C, and pH 4.0. The purified laccase was the first laccase isolated from genus Gymnopus with high thermostability, pH stability, and effective decolorization toward dyes, suggesting that it has potentials for textile and environmental applications.

Two Cu(II) coordination polymers: Heterogeneous catalytic Knoevenagel condensation reaction and treatment activity on atherosclerosis via regulating the expression of the COX-2 in vascular endothelial cells.

By altering auxiliary nitrogen-donor ligands, two novel coordination polymers (CPs) containing Cu(II) formulated as [Cu2.5(L)(trz)2(H2O)2]·2H2O (1) (Htrz = 1,2,4-triazole and H3L = 5-(4-carboxybenzyloxy)isophthalic acid) and [Cu(HL)(Hbiz)] (2, Hbiz = benzimidazole) have been produced under the hydrothermal conditions. The complex 2 with both acidic and basic sites was investigated as heterogeneous catalyst, which reveals highly efficient catalytic property of the Knoevenagel condensation reaction. Dynamic changes of coagulation parameters during atherosclerosis was also explored via detecting activated partial thromboplastin time (APTT) and prothrombin time (PT), and the results showed that compared with CP 2, CP 1 has a stronger improvement on the coagulation parameters during atherosclerosis. Then, the high-sensitivity C-reactive protein and matrix metalloproteinase-1 released by the atherosclerotic segment was detected with enzyme linked immunosorbent assay (ELISA) detection, which also revealed that CP 1 could obviously decrease the inflammatory mediator released by the atherosclerotic segment, but not CP 2. And, the cyclooxygenase-2 (COX-2) relative expression level in vascular endothelial cells was detected via the real time RT-PCR. The results of the real time reverse transcription-polymerase chain reaction (RT-PCR) indicated that CP 1 has stronger activity on inhibiting the Notch signaling pathway than CP 2. Finally, we got this information, CP 1 has excellent application values on the coagulation parameters during atherosclerosis via regulating the expression of the COX-2 in vascular endothelial cells.

Species clarification of the culinary Bachu mushroom in western China.

The Bachu mushroom, previously identified as Helvella leucopus, is characterized by a saddle-shaped, to irregularly lobed pileus, with a gray, brown to blackish hymenium and a whitish to pale receptacle surface and white, terete stipe with enlarged basal grooves. It has high economic value, mostly as a dietary supplement in western China, and its medicinal functions have raised broad interest. In the present paper species of the Bachu mushroom in Xinjiang Autonomous Region, western China were investigated with morphology and DNA sequence data. Phylogenetic analyses inferred from ITS, 28S and TEF1 sequence data strongly supported lineages corresponding to morphological features. The Bachu mushroom, which differs from the European Helvella leucopus, comprises two distinct new species, namely Helvella bachu and Helvella subspadicea. In this paper we introduce the new species with descriptions and figures and compare them with similar taxa. The European Helvella spadicea is also re-examined, described and illustrated.

Comparative Analysis of Sporulating and Spore-Deficient Strains of Agrocybe salicacola Based on the Transcriptome Sequences.

The large number of spores produced by edible mushrooms cause many problems, including causing lung disease, depleting natural genetic diversity, and reduced quality of fruiting bodies. Obtaining spore-deficient strains and understanding the underlying molecular mechanisms of such strains are important for breeding work. In this study, we crossed monokaryotic strains isolated from the edible fungi Agrocybe salicacola to obtain three spore-deficient strains with losses of the sterigmata on the surface of the lamella. A mating test revealed that recessive alleles distributed in some strains might control sterigmata development during the mitotic or meiotic phases. Transcriptome analysis revealed that the majority of the genes involved in DNA mismatch repair, base excision repair, and homologous recombination exhibited down-regulated expression patterns in the mutant fruiting bodies. Five genetic fragments, which were highly similar to the GTP-cyclohydrolase encoding gene, the DNA repair gene rad 8, and cell wall integrity and stress response component-encoding genes, were all expressed exclusively in the wild-type strains; these findings provide important information for the study of the spore development of edible fungi.

Gene Expressing Difference in Sclerotial Formation of Morchella conica.

The difference of gene expression between sclerotia-producing and non-sclerotia-producing single spore isolates from Morchella conica were preliminary analyzed by mRNA differential display reverse transcription-polymerase chain reaction (RT-PCR) technique and 67 differential gene fragments were obtained. Fifty-eight of their second PCR products were cloned and sequenced. Thirteen special differential gene fragments related to sclerotial formation were validated by semi-quantitative RT-PCR. Some gene fragments had certain homologies with lipoprotein, cyclin-dependent kinase C-3, glycerophosphoryl diester phosphodiesterase, Rho GDP-dissociation inhibitor, gamma-aminobutyrate permease, OmpA family protein, Transcript antisense to ribosomal RNA protein, sodium-calcium exchange protein and keratin-associated proteins 5, 6. In addition, the putative protein of some DNA fragments had higher similarity with hypothetical protein-coding gene in NCBI database, as well as some were only putative gene fragments. All these fragments were speculated to be the functional gene associated with sclerotial formation in morel.

A novel ribonuclease with potent HIV-1 reverse transcriptase inhibitory activity from cultured mushroom Schizophyllum commune.

A 20-kDa ribonuclease (RNase) was purified from fresh fruiting bodies of cultured Schizophyllum commune mushrooms. The RNase was not adsorbed on Affi-gel blue gel but adsorbed on DEAE-cellulose and CM-cellulose. It exhibited maximal RNase activity at pH 6.0 and 70°C. It demonstrated the highest ribonucleolytic activity toward poly (U) (379.5 µ/mg), the second highest activity toward poly (C) (244.7 µ/mg), less activity toward poly (A) (167.4 µ/mg), and much weaker activity toward poly (G) (114.5 µ/mg). The RNase inhibited HIV-1 reverse transcriptase with an IC(50) of 65 µM. No effect on [(3)H-methyl]-thymidine uptake by lymphoma MBL2 cells and leukemia L1210 cells was observed at 100 µM concentration of the RNase. A comparison of RNases from S. commune and Volvariella volvacea revealed that they demonstrated some similarities in N-terminal amino acid sequence, optimum pH and polyhomoribonucleotide specificity. However, some differences in chromatographic behavior and molecular mass were observed.