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Cellulase gene expression in Trichoderma reesei is highly responsive to environmental cues and is under stringent regulation by multiple transcription factors. XYR1 (Xylanase regulator 1) has been identified as the most important transcriptional activator of cellulase/hemicellulase gene expression although the precise transactivating mechanism remains largely elusive. Here we show that the activation domain of XYR1 interacts with the T. reesei homolog of the TrSNF12 subunit of SWI/SNF complex. Deletion of Trsnf12 markedly impaired the induced cellulase gene expression. Individual loss of other SWI/SNF subunits including the catalytic subunit also severely compromised cellulase gene expression and interfered with loss of histone H4 in the cbh1 and eg1 promoters upon cellulose induction. In addition, we find that the SWI/SNF occupancy on cellulase gene promoters strictly required XYR1 and TrSNF12 but TrSNF12 was dispensable for the XYR1 binding to these promoters. These data suggest a model in which XYR1 recruits SWI/SNF through direct interactions with TrSNF12 to remodel chromatin at cellulase gene promoters, thereby activating cellulase gene expression to initiate the cellulolytic response in T. reesei.

Cellulase gene expression in the model cellulolytic fungus Trichoderma reesei is supposed to be controlled by an intricate regulatory network involving multiple transcription factors. Here, we identified a novel transcriptional repressor of cellulase gene expression, Rce1. Disruption of the rce1 gene not only facilitated the induced expression of cellulase genes but also led to a significant delay in terminating the induction process. However, Rce1 did not participate in Cre1-mediated catabolite repression. Electrophoretic mobility shift (EMSA) and DNase I footprinting assays in combination with chromatin immunoprecipitation (ChIP) demonstrated that Rce1 could bind directly to a cbh1 (cellobiohydrolase 1-encoding) gene promoter region containing a cluster of Xyr1 binding sites. Furthermore, competitive binding assays revealed that Rce1 antagonized Xyr1 from binding to the cbh1 promoter. These results indicate that intricate interactions exist between a variety of transcription factors to ensure tight and energy-efficient regulation of cellulase gene expression in T. reesei. This study also provides important clues regarding increased cellulase production in T. reesei.

Scope In this study, we investigated the beneficial effects and the underlying mechanism of epigallocatechin gallate (EGCG) in adipose tissues of rats fed with a high-fat diet (HFD). Methods and results Fasting plasma insulin, epididymal fat coefficient and free fatty acids, homeostasis model assessment-insulin resistance index, and the average glucose infusion rate were determined. EGCG significantly decreased free fatty acids, fasting insulin, homeostasis model assessment-insulin resistance index, and epididymal fat coefficient, and increased glucose infusion rate in HFD group. The levels of toll-like receptor 4, TNF receptor associated factor 6, inhibitor-kappa-B kinase β, p-nuclear factor κB, tumor necrosis factor α, and IL-6 in the EGCG group were all significantly lower than the HFD control group. EGCG also decreased the level of phosphorylated insulin receptor substrate 1 and increased phosphoinositide-3-kinase and glucose transporter isoform 4 in the HFD group. Decreased macrophage infiltration was in EGCG group versus HFD group, and the protein level of CD68 in EGCG group was also significantly lower than that of HFD group. Conclusion EGCG attenuated inflammation by decreasing the content of macrophages, interfered the toll-like receptor 4 mediated inflammatory response pathway, thus, improving insulin signaling in adipose tissues.

Multi-walled carbon nanotubes (MWCNTs) decorated with PdxCoy (the nominal atomic ratios of Pd to Co were 3:1, 3:1.5, 3:2, 3:3, respectively) nanoparticles (denoted as PdxCoy/MWCNTs ) were fabricated by a simple pyrolysis process, in which room temperature ionic liquids (RTILs) of butyl-3-methylimidazolium hexafluorophosphate (denoted as [BMIM]PF6) was used as the solvent. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were all used to characterize the PdxCoy/MWCNTs catalysts, showing that the PdxCoy particles were dispersed on the surface of the MWCNTs with an average particle size of ~25.0 nm. The electro-catalytic activity of the PdxCoy/MWCNTs catalysts toward ethanol oxidation reaction (EOR) was examined by cyclic voltammetry (CV). It was revealed that the onset potential was ~90 mV lower and the peak current was about four times higher for ethanol oxidation for Pd3Co1.5/MWCNTs compared to those of Pd3Co1/MWCNTs. The possible catalysis mechanisms of the Pd3Co1.5/MWCNTs toward EOR were also discussed.

Gold (Au) huge particles were prepared by a pyrolysis process of AuCl3 dissolved in distilled water in the presence of multi-walled carbon nanotubes (MWCNTs). X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the obtained samples. The results showed that Au huge particles with a diameter close to 500 nm were fabricated. The electrocatalytic performance of the huge Au particles modified graphite electrode in the oxygen reduction reaction (ORR) was investigated using cyclic voltammetry (CV). It indicated that the pyrolysis time was a key factor that can affect the electrocatalysis of Au huge particles towards ORR. Developing a novel and simple method of pyrolysis for fabricating Au huge particles is the main contribution of this work, which will be very helpful in the preparation of Au huge particles on a large scale.

OBJECTIVE To evaluate the ability of bacille-Calmette Guerin (BCG) to induce caspase-independent cell death and release the necrosis-associated chemokine high molecular group box protein 1 (HMGB1) from urothelial carcinoma (UC) cells; a correlative clinical trial determined if BCG treatment resulted in increased urinary levels of HMGB1. PATIENTS, MATERIALS AND METHODS The human UC cell lines 253 J and T24 were pretreated with apoptosis inhibitors, exposed to BCG, and cell viability and ultrastructural changes measured. HMGB1 levels were assessed in cell culture supernatant after BCG treatment. The expression/function of HMGB1 receptors on the UC cell lines was determined by reverse transcription-polymerse chain reaction and the ability of exogenous HMGB1 to activate nuclear factor (NF)-κB signalling assessed. An HMGB1 enzyme-linked immunosorbent assay was used to measure HMGB1 levels in urine obtained from BCG-treated patients. RESULTS Inhibition of apoptotic pathways failed to inhibit BCG-induced cell death in UC cells. Electron microscopy showed BCG-dependent ultrastructural changes consistent with cellular necrosis. BCG exposure resulted in a binary increase in cell culture supernatant levels of HMGB1. UCs expressed multiple HMGB1 receptors. Treatment of UCs with HMGB1 activated NF-κB. In the clinical setting, six of seven patients had increased urinary levels of HMGB1 at 24 h after BCG treatment. CONCLUSIONS BCG causes direct cytotoxicity in a subpopulation of UC cells. This cytotoxicity is caspase-independent and associated with ultrastructural changes and cellular protein release (HMGB1), characteristic of necrosis. Urinary levels of HMGB1 can be elevated in patients after BCG treatment. The expression and function of HMGB1 receptors in UC cells, coupled with the known role of HMGB1 on the host immune response, suggest a role for necrosis and HMGB1 release in the antitumour effect of BCG.