Glutamine synthetase regulation by dexamethasone,RU486, and compound A in astrocytes derived from aged mouse cerebral hemispheres is mediated via glucocorticoid receptor

Molecular and Cellular Biochemistry - Glucocorticoids (GCs) regulate astrocyte function, while glutamine synthetase (GS), an enzyme highly expressed in astrocytes, is one of the most remarkable...     

Monitoring novel metabolic pathways using metabolomics and machine learning: induction of the phosphoketolase pathway in Aspergillus nidulans cultivations

The physiological phenotype of Aspergillus nidulans was determined under different environmental conditions through the quantification of the intracellular and extracellular metabolite pools and clear evidence of the presence of a novel fungal metabolic pathway, the phosphoketolase pathway, was obtained. Induction of the phosphoketolase pathway resulted after blocking the EMP pathway through the deactivation of glyceraldehyde-3-P dehydrogenase (G3PD). Deactivation of G3PD in cultivations of A. nidulans on glucose and xylose led to a 10-fold decrease in the specific growth rate; however, growth could still be sustained solely through the phosphoketolase pathway. Metabolomics and machine learning tools were successfully used to monitor the alteration caused by the inhibition of G3PD in the metabolism of A. nidulans grown on glucose, xylose, acetate as well as mixtures of glucose or xylose with acetate. This is the first study that demonstrates in vivo that the fungal central carbon metabolism includes an active phosphoketolase pathway.     

On using network RAM as a non‐volatile buffer

File systems and databases usually make several synchronous disk write accesses in order to make sure that the disk always has a consistent view of their data, so that it can be recovered in the case of a system crash. Since synchronous disk operations are slow, some systems choose to employ asynchronous disk write operations that improve performance at the cost of low reliability: in case of a system crash all data that have not yet been written to disk are lost. In this paper we describe a softwarebased NonVolatile RAM system that achieves the high performance of asynchronous write operations without sacrificing the reliability of synchronous write operations. Our system takes a set of volatile main memories residing in independent workstations and transforms it into a nonvolatile memory buffer – much like RAIDS do with magnetic disks. It then uses this nonvolatile buffer as an intermediate storage space in order to acknowledge synchronous write operations before actually writing the data to magnetic disk, but after writing the data to (intermediate) stable storage. We demonstrate the performance advantages of our system using both simulation and experimental evaluation.     

Induction, purification, and characterization of two extracellular alpha-L-arabinofuranosidases from Fusarium oxysporum

In the presence of L-arabinose as sole carbon source, Fusarium oxysporum produces two alpha-L-arabinofuranosidases (ABFs) named ABF1 and ABF2, with molecular masses of 200 and 180 kDa, respectively. The two F. oxysporum proteins have been purified to homogeneity. The purified enzymes are composed of three equal subunits and are neutral proteins with pIs of 6.0 and 7.3 for ABF1 and ABF2, respectively. With p-nitrophenyl alpha-L-arabinofuranoside (pNPA) as the substrate, ABF1 and ABF2 exhibited Km values of 0.39 and 0.28 mmol.L(-1), respectively, and Vmax values of 1.6 and 4.6 micromol.min(-1).(mg of protein)(-1), respectively, and displayed optimal activity at pH 6.0 and 50-60 degrees C. ABFs released arabinose only from sugar beet arabinan and not from wheat soluble and insoluble arabinoxylans. The enzymes were not active on substrates containing ferulic acid ester linked to C-5 and C-2 linkages of pNPA showing that phenolic substituents of pNPA sterically hindered the action of ABFs.     

Yeast, beef and pork extracts counteract Clostridium difficile toxin A enterotoxicity

Clostridium difficile is responsible for a large proportion of nosocomial cases of antibiotic-associated diarrhoea and pseudomembranous colitis. The present study provides evidence that yeast, beef and pork extracts, ingredients commonly used to grow bacteria, can counteract C. difficile toxin A enterotoxicity in vitro and in vivo . In model intestinal epithelial cells the individual extracts could prevent the toxin A-induced decrease in epithelial barrier function and partially prevented actin disaggregation and cell rounding. Mice with ad libitum access to individual extracts for 1 week had almost complete reduction in toxin A-induced fluid secretion in intestinal loops. Concomitantly, the toxin A-induced expression of the essential proinflammatory mediator Cox-2 was normalized. Moreover this protective effect was also seen when mice received only two doses of extract by intragastric gavage within 1 week. These results show that yeast, beef and pork extracts have the potential to counteract the intestinal pathogenesis triggered by C. difficile toxin A.     

Immune Response Gene Expression in Colorectal Cancer Carries Distinct Prognostic Implications According to Tissue,Stage and Site: A Prospective Retrospective Translational Study in the Context of a Hellenic Cooperative Oncology Group Randomised Trial

Background

Although host immune response is an emerging prognostic factor for colorectal cancer, there is no consensus on the optimal methodology, surrogate markers or tissue for study.

Patients and Methods

Tumour blocks were prospectively collected from 344 patients with stage II/III colorectal cancer (CRC) treated with adjuvant chemotherapy. Whole section lymphocytic infiltration was studied along with mRNA expression of CD3Z, CD8, CD4, CXCL9, CXCL13, IGHM, FOXP3, SNAI2 and ESR1 by qRT-qPCR in tissue microarray (TMA) cores from the centre of tumour, invasive margin and adjacent normal mucosa.

Results

Lymphocytic infiltration, deficient MMR (10.9%), KRAS (40.7%) and BRAF (4.9%) mutations or single mRNA gene expression were not prognostic. Tumour ESR1 gene expression (Hazard Ratio [HR] for relapse 2.33, 95% CI 1.35-4.02; HR for death 1.74, 95% CI 1.02-2.97) and absence of necrosis (HR for relapse 1.71, 95% CI 1.05-2.71; HR for death 1.98, 95% CI 1.14-3.43) were adverse prognostic features. We used CD3Z and CD8 expression in order to devise the mRNA-based Immune Score (mIS) and proceeded to partitioning analysis in 267 patients, with age, stage, tumour site (Right vs Left CRC), KRAS mutation and tumour mIS as input factors. Only in patients with stage III right-sided colon cancer, a low immune response was associated with inferior disease-free survival (mIS-low, HR for relapse 2.28, 95% CI 1.05-8.02). No prognostic significance was seen for tumour mIS in any other stage or site of CRC, or for a similar mIS score derived from adjacent normal mucosa. Independent adverse prognostic significance was retained in multivariable analysis for absence of necrosis, tumour ESR1 expression in all patients and low tumour mIS in stage III right-sided CRC.

Conclusions

In localised CRC, mRNA-based CD3Z/CD8 profiling of tumour immune response may have stage, site and tissue-specific prognostic significance, along with ESR1 expression.

Trial Registration

ANZCTR.org.au ACTRN12610000509066     

Penicillium brasilianum as an enzyme factory; the essential role of feruloyl esterases for the hydrolysis of the plant cell wall

The production of arabinoxylan-degrading enzymes by the fungus Penicillium brasilianum, grown on different carbon and nitrogen sources as well as different environmental conditions was investigated. Highest feruloyl esterase (225 mU/ml) and alpha-L-arabinofuranosidase (211 mU/ml) activities were obtained when P. brasilianum was grown on sugar beet pulp, whereas maximum xylanase (17 U/ml) activity was found during growth on oat spelt xylan. Yeast extract was the preferable nitrogen source for the production of all the three enzymes. Further optimization of the production of the crude enzyme mixture was examined by experimental design using a D-optimal quadratic model. Investigation of the microbial regulation of enzyme production showed that the presence of free ferulic acid further stimulated the production and pointing to that the fungal regulatory mechanism involved a coordinated production and secretion of feruloyl esterase, xylanase and alpha-L-arabinofuranosidase. Since agroindustrial by-products are a potential source of phenolic acids, crude enzyme mixtures of P. brasilianum were tested for their hydrolysis abilities against eight complex or model substrates. While total release of phenolic acids and pentoses was not observed, the synergistic enhancement of hydrolysis in the presence of feruloyl esterase was clearly demonstrated.