Salt tolerance of Arabidopsis thaliana requires maturation of N-glycosylated proteins in the Golgi apparatus

Protein N-glycosylation in the endoplasmic reticulum (ER) and in the Golgi apparatus is an essential process in eukaryotic cells. Although the N-glycosylation pathway in the ER has been shown to regulate protein quality control, salt tolerance, and cellulose biosynthesis in plants, no biological roles have been linked functionally to N-glycan modifications that occur in the Golgi apparatus. Herein, we provide evidence that mutants defective in N-glycan maturation, such as complex glycan 1 (cgl1), are more salt-sensitive than wild type. Salt stress caused growth inhibition, aberrant root-tip morphology, and callose accumulation in cgl1, which were also observed in an ER oligosaccharyltransferase mutant, staurosporin and temperature sensitive 3a (stt3a). Unlike stt3a, cgl1 did not cause constitutive activation of the unfolded protein response. Instead, aberrant modification of the plasma membrane glycoprotein KORRIGAN 1/RADIALLY SWOLLEN 2 (KOR1/RSW2) that is necessary for cellulose biosynthesis occurred in cgl1 and stt3a. Genetic analyses identified specific interactions among rsw2, stt3a, and cgl1 mutations, indicating that the function of KOR1/RSW2 protein depends on complex N-glycans. Furthermore, cellulose deficient rsw1-1 and rsw2-1 plants were also salt-sensitive. These results establish that plant protein N-glycosylation functions beyond protein folding in the ER and is necessary for sufficient cell-wall formation under salt stress.     

Interleukin-17 and lipopolysaccharides synergistically induce cyclooxygenase-2 expression in human intestinal myofibroblasts

BACKGROUND: Colonic subepithelial myofibroblasts (SEMF) play a role in the modulation of mucosal inflammatory responses via the secretion of various inflammatory mediators. In the present study the effects of interleukin (IL)-17 and lipopolysaccharides (LPS) on cyclooxygenase (COX) expression in colonic SEMF were investigated. METHODS: The expression of COX-1 and -2 proteins and mRNAs were determined by western and northern blotting, respectively. Nuclear factor (NF)-kappaB DNA binding activities were evaluated by electrophoretic gel mobility shift assays (EMSA). RESULTS: The expression of COX-2 protein and mRNA was rapidly induced by the addition of IL-17 and LPS, whereas COX-1 expression was not affected by these factors. The effects of IL-17 and LPS were detected in a dose- and time-dependent manner. Furthermore, IL-17 and LPS synergistically induced COX-2 mRNA and protein expression. The EMSA demonstrated that the addition of IL-17 and LPS induced NF-kappaB activation within 1.5 h after stimulation, and a blockade of NF-kappaB activation by a recombinant adenovirus containing a stable form of IkappaBa markedly reduced the IL-17- and LPS-induced COX-2 mRNA expression. In these cells, the expression of Toll-like receptor (TLR)-4, which is a cellular receptor for LPS, was detected. CONCLUSION: Interleukin-17 and LPS play an important role in the induction of COX-2 in SEMF. These findings suggest that COX-2 expression and prostaglandin synthesis might be regulated by both T-cell-derived factor (IL-17) and bacterial products (LPS) in the inflamed mucosa.     

Initiation sites for discontinuous DNA synthesis of bacteriophage T7

We have previously shown that the discontinuous replication of bacteriophage T7 DNA is primed by tetraribonucleotides (major component) or pentaribonucleotides. Both tetramers and pentamers start with pppA-C and are rich in A and C at the third and fourth nucleotides. In this study, the sites of transition from primer RNA to DNA in vivo have been located on a 340-nucleotide segment of the H strand of the T7 genome by 32P-labeling in vitro of the 5'-hydroxyl ends of DNA resulting from alkaline hydrolysis of RNA-linked T7 DNA fragments. Five strong transition sites were detected with a common sequence 5'-G-A-C-N1-N2-N3-N4-3', in which N1 was either C or A, N2 ws A, C, or G, and either N3 or N4 was the nucleotide for the switchover to DNA synthesis. We conclude that the complementary sequence 3'-C-T-G-G/T-N'2-(N'3)-5' in the template strand is the most frequently used signal for synthesis of primer RNA. Whereas primer-RNA synthesis starts at a precisely defined nucleotide, the transition to DNA synthesis varies within two nucleotides. Because the observed signal sequence would be present on a statistical basis once per 128 nucleotides, only about 10% of the existing signals are used for primer synthesis in each round of replication so that nascent fragments 1000-2000 long result. This provides an unexpected flexibility for RNA priming of DNA synthesis.     

Interferon therapy prolonged life expectancy among chronic hepatitis C patients

BACKGROUND & AIMS: The effects of interferon therapy in chronic hepatitis C patients on survival are unclear. Our objective was to analyze survival among a large cohort of chronic hepatitis C patients. METHODS: We used a retrospective cohort study design in the setting of 7 university hospitals and 1 regional core hospital in Japan. Our study included 2889 patients with histological-proven chronic hepatitis C: 2430 patients received interferon therapy, and 459 patients were untreated. For intervention, the median dose and duration of interferon administration was 480 million units and 137 days, respectively. For measurements, survival status was confirmed by medical records or direct questionnaires. The effect of interferon therapy on survival was assessed by standardized mortality ratio (SMR) based on published mortality among the Japanese general population and by risk ratio calculated by proportional hazards regression. RESULTS: Thirty of 459 untreated patients, 7 of 817 virologic sustained responders, and 49 of 1613 nonresponders died in 5.4-years follow-up. Fifty-eight (67%) of 86 patient deaths were due to liver diseases (39 to hepatocellular carcinoma). Compared with the general population, overall mortality was high among untreated patients (SMR: 1.9; CI: 1.3-2.8) but not among interferon-treated patients (SMR: 0.9; CI: 0.7-1.1). The risk of death was reduced, compared with untreated patients, among interferon-treated patients (risk ratio for overall death: 0.367; CI: 0.236-0.596; for liver-related death: 0.284; CI: 0.164-0.494) and among sustained responders (risk ratios: 0.148; CI: 0.064-0.343 and 0.050; CI: 0.012-0.216). The risk of liver-unrelated deaths remained unchanged. CONCLUSIONS: Interferon therapy improved survival of chronic hepatitis C patients by preventing liver-related deaths.     

Control of the dual emission from a thermally activated delayed fluorescence emitter containing phenothiazine units in organic light-emitting diodes

The development of single-component organic dual light-emitting molecules is of interest for a range of applications including white organic light-emitting diodes. Herein, a new thermally-activated delayed fluorescent molecule containing 4,6-bis-phenyl phenothiazine as donor units and 2-thiophene-1,3,5-triazine as acceptor unit was synthesized using a simple cost-effective method. This compound shows two stable molecular conformations due to the presence of the phenothiazine units in its molecular structure. These conformers exhibit different photophysical properties in both solution and thin films. The electroluminescence properties of this novel emitter were then examined in organic light-emitting diodes and the results provide useful insights into the influence of the device architecture on the dual emission characteristics. The experimental results were consistent with the optical simulations and the optimized architecture led to the fabrication of electroluminescent devices with an external quantum efficiency of 11.5% and a maximum luminance value of 10 370 cd m⁻².

A novel TADF emitter showing dual emission is synthesized and applied to OLEDs with an external quantum efficiency of 11.5%.     

Effects of ethanol on the pancreas of disulfiram-treated rats

To study the effects of ethanol on disulfiram-treated rats, we administered ethanol orally at a does of 2000 mg/kg, twice daily for 5 days. The administration of ethanol or disulfiram alone produced no recognizable changes in pancreatic acinar cells. Ethanol administration. in disulfiram-treated rats resulted in a decrease in the content of zymogen granules in acinar cells, and the appearance of intraplasmic vacuolization. Electron microscopically, these vacuoles appeared on the basal side of nuclei. In addition, similar vacuoles appeared in liver cells, and these vacuolizations seemed to show lipid inclusions. However, ethanol administration to disulfiram-treated rats did not cause inflammatory changes or edema in the pancreas. A comparison of blood ethanol levels in rats receiving ethanol alone and disulfiram plus ethanol showed no significant difference, but acetaldehyde levels in rats receiving ethanol plus disulfiram rats were significantly higher than those in rats receiving ethanol alone. These findings suggested that acetaldehyde caused a decrease of zymogen granules and the presence of lipid inclusions in pancreatic acinar cells.