These data suggest that IL-1beta-induced NO production in cardiac myocytes lowers energy production and myocardial contractility through a direct attack on the mitochondria, rather than through cGMP-mediated pathways.
Small metal-binding peptides, cadystins, with the general structure of (gamma-Glu-Cys)n-Gly ((gamma EC)nG), were synthesized in a cell-free system of fission yeast to examine the in vivo synthetic pathway. The crude enzyme for cadystin synthesis was prepared by ammonium sulfate precipitation (75% saturation) from the 120,000 x g supernatant of the cell extract, and the excess salt in the enzyme fraction was removed by Sephadex gel filtration. Using this crude enzyme fraction, it was shown that there were two pathways for cadystin biosynthesis. One pathway is gamma-Glu-Cys (gamma EC) dipeptidyl transfer from both glutathione (gamma ECG) and cadystins to glutathione and cadystins. The other one is gamma EC polymerization from (gamma EC)n and glutathione to (gamma EC)n + i, followed by glycine addition with glutathione synthetase.
Exposure of Schizosaccharomyces pombe cells to various stresses including 0.2 mM hydrogen peroxide, 50 microM menadione, 10 J/m2 of UV irradiation at 255 nm, and high osmolarity (0.5 M sorbitol or 0.3 M NaCl) induces catalase [EC 1.11.1.6] activity. A part of the catalase gene of S. pombe was amplified by PCR with oligonucleotide primers designed from amino acid sequences conserved in several species of catalases. The catalase gene including its flanking sequence of S. pombe was cloned from a genomic DNA library of S. pombe, which was constructed on the EMBL3 vector, using the PCR-amplified DNA as a radioactive probe. A 3.5 kb HindIII fragment, which hybridized with the PCR-amplified probe, was subcloned into pUC19 and sequenced. The fragment contains one long open reading frame without any intron. The polypeptide deduced from the nucleotide sequence consists of 512 amino acid residues and is homologous to several other catalases. Amino acid sequences of the proteolytic peptides obtained from the purified catalase of S. pombe coincided with the amino acid sequence predicted from the DNA sequence. Transcription of this gene starts at 370 bases upstream of the initiation methionine codon. Northern blot analyses of the catalase mRNA revealed that the stresses which induce the catalase activity also induce the transcription of the catalase gene. The induction of the catalase mRNA by hydrogen peroxide is not inhibited by cycloheximide or staurosporine.
The present study demonstrates that in both normal and diabetic rats, preservation of mitochondrial oxidative phosphorylation and inhibition of glycolysis during ischemia can contribute to preconditioning-induced cardioprotection. Furthermore, our data suggest that diabetic myocardium may benefit more from preconditioning than normal myocardium, possibly as a result of the reduced production of glycolytic metabolites during sustained ischemia and the concomitant attenuation of intracellular acidosis.
Circadian variation in the expression of brain‐derived neurotrophic factor (BDNF) indicates that BDNF is involved in the regulation of diurnal rhythms in a variety of biological processes. However, it is still unclear which brain regions alter their BDNF levels in response to external light input. Therefore, in selected brain regions of adult male rats, we investigated diurnal variation, as well as the effects of a single eight‐hour phase advance of the light‐dark cycle, on the levels of BDNF and of other neurotrophins. The cerebellum, hippocampus and cerebral cortex containing visual cortex (VCX) showed diurnal variation in BDNF protein levels and the VCX also in NT‐3 levels. In the VCX and the region containing the entorhinal cortex and amygdala (ECX), BDNF protein levels were increased 12 h after the phase advance, while BDNF mRNA levels were increased significantly in the VCX and slightly in the ECX after 4 h. After one week, however, BDNF protein levels were reduced in eight brain regions out of 13 examined. BDNF levels in the ECX and VCX were significantly different between light rearing and dark rearing, while a hypothyroid status did not produce an effect. Cyclic AMP responsive element‐binding protein (CREB), a transcription factor for BDNF, was greatly activated by the phase advance in the ECX and VCX, suggesting the existence of CREB‐mediated pathways of BDNF synthesis that are responsive to external light input.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.