Search results for " expression"
showing 10 items of 4731 documents
17β-Estradiol-dependent regulation of chaperone expression and telomerase activity in the marine sponge Geodia cydonium
1999
It is known that species belonging to the lowest metazoan phylum, the Porifera (sponges), do not develop tumors. Sponge cells share with tumor cells of higher animals at least one characteristic; they contain high levels of telomerase activity, suggesting that they possess a high proliferation capacity. This assumption, however, has not been substantiated experimentally. In addition, sponges show a specific bauplan, leading us to postulate that they undergo apoptosis to replace a given set of cells at a given time. In the present study, 17β-estradiol (βE2) was used as a defined agent to assess its effect on both the telomerase activity and the process of apoptosis in the marine sponge Geodi…
Long term p38-a deficiency up-regulates antioxidant enzymes through compensatory NF-?B activation
2015
p38a MAPK may function as a mediator of reactive oxygen species signaling and thus p38a is considered a sensor of oxidative stress. In liver-specific p38a knock-out (KO) adult mice we previously found glutathione depletion and down-regulation of antioxidant enzymes. Our aim was to assess the influence of long-term p38a deficiency on oxidative stress and on the regulation of antioxidant enzymes in liver of old mice. To this end, wild type or liver-specific KO mice after weaning, at 4-6 months of age, or at 24 months of age were used. Reduced glutathione (GSH) and oxidized glutathione levels were determined by mass spectrometry, gene expression of antioxidant enzymes was determined by RT-PCR,…
Validation strategies for antibodies targeting modified ribonucleotides
2020
Chemical modifications are found on almost all RNAs and affect their coding and noncoding functions. The identification of m6A on mRNA and its important role in gene regulation stimulated the field to investigate whether additional modifications are present on mRNAs. Indeed, modifications including m1A, m5C, m7G, 2′-OMe, and Ψ were detected. However, since their abundances are low and tools used for their corroboration are often not well characterized, their physiological relevance remains largely elusive. Antibodies targeting modified nucleotides are often used but have limitations such as low affinity or specificity. Moreover, they are not always well characterized and due to the low abun…
Antioxidants in skeletal muscle physiology, a radically different approach.
2015
Regular physical exercise has many health benefits (1). Paradoxically, it is also clear that contracting skeletal muscles generate reactive oxygen species (ROS) and that prolonged and intense exercise can result in oxidative damage to cellular constituents (2-4). Reactive oxygen species production is dependent on the intensity of the exercise with higher amount of ROS generated by strenuous exercise (5, 6). Antioxidants may reduce the adverse effects of exercise-induced ROS (2-4). However, ROS are not only toxic but rather play an important role in cell signalling and in the regulation of gene expression (7, 8) and force production in skeletal muscle (9). Thus, we have recently raised quest…
Differential Expression of theS-Adenosyl-l-Methionine Synthase Genes during Pea Development1
1998
Abstract Two genes coding for S-adenosyl-l-methionine synthase (SAMS, EC 2.5.1.6) were previously isolated from pea (Pisum sativum) ovaries. Both SAMS genes were highly homologous throughout their coding regions but showed a certain degree of sequence divergence within the 5′ and the 3′ untranslated regions. These regions have been used as gene-specific probes to analyze the differential expression of SAMS1and SAMS2 genes in pea plants. The ribonuclease protection assay revealed different expression patterns for each individual gene. SAMS1 was strongly expressed in nearly all tissues, especially in roots. SAMS2 expression was weaker, reaching its highest level at the apex. Following pollina…
Revisiting delta-6 desaturase regulation by C18 unsaturated fatty acids, depending on the nutritional status.
2009
Dietary polyunsaturated fatty acids (PUFA) play a key role in regulating delta-6 desaturase (D6D), the key enzyme for long-chain PUFA biosynthesis. Nevertheless, the extent of their effects on this enzyme remains controversial and difficult to assess. It has been generally admitted that C18 unsaturated fatty acids (UFAs) regulate negatively delta-6 desaturase (D6D). This inhibition has been evidenced in regard to a high glucose/fat free (HG/FF) diet used in reference. However, several nutritional investigations did not evidence any inhibition of desaturases when feeding fatty acids. Because the choice of the basal diet appeared to be of primary importance in such experiments, our goal was t…
072 Collagen gene expression and tenascin pattern in normal, osteoarthritic, and rheumatoid connective tissues
1992
The extracellular matrix consists of four major components, namely collagens, elastin, proteoglyeans and glycoproteins. Collagens are important members of the ECM, forming a family of at least t 3 different structurally related proteins. Tenascin, synonymous with cytoactin, hexabrachion and J1, is a new member of matrix glycoproteins with a molecular mass of 1200 kD. It exhibits a "hexabrachion" structure with an ellipsoid central globule from which six arms of 75 nm in length diverge in a T-junction arrangement [1]. Rheumatoid arthritis (RA) belongs to the group of connective tissue diseases. In contrast to abundant data about ECM-changes in systemic sclerodermia [2] the matrix alterations…
Ontogenetic variations of some enzymes indicentrarchus labrax(Serranidae)
1989
Abstract The ontogenesis of isozyme patterns of alcohol dehydrogenase (ADH), glycerol‐3‐phosphate dehydrogenase (α‐GPDH), lactate dehydrogenase (LDH), malate dehydrogenase (MDH), glucose‐6‐phosphate dehydrogenase (G‐6‐PD) and glucosephosphate isomer‐ase (GPI) in Dicentrarchus labrax was studied. ADH is active only in the liver of the adult; a‐GPDH is active in only two tissues in the adult: the A2 isozyme in white skeletal muscle and the B2 isozyme in the liver. Differential gene expression was found only for LDH, MDH and GPI, which have polymeric structure. The LDH, MDH and GPI isozymes 30 days after hatching were completely active and showed patterns very similar to those of the adult. Sp…
The dcuD (former yhcL ) gene product of Escherichia coli as a member of the DcuC family of C4-dicarboxylate carriers: lack of evident expression
1999
The dcuD gene (formerly yhcL) of Escherichia coli shows significant sequence similarity only to the dcuC gene of E. coli, which encodes a C4-dicarboxylate carrier (DcuC) that functions during anaerobic growth. Inactivation of dcuD had no effect on the growth of E. coli under a large number of conditions and led to no detectable changes in phenotype. Translational dcuD'-'lacZ gene fusions were not significantly expressed in the presence of dicarboxylates or monocarboxylates under oxic or anoxic conditions. Other potential substrates such as amino sugar derivatives, amino acids, and alpha-aspartyl dipeptides also did not lead to expression of dcuD. Changes in medium composition, pH, ionic str…
The gene encoding polyneuridine aldehyde esterase of monoterpenoid indole alkaloid biosynthesis in plants is an ortholog of theα/β hydrolase super fa…
2000
The biosynthesis of the anti-arrhythmic alkaloid ajmaline is catalysed by more than 10 specific enzymes. In this multistep process polyneuridine aldehyde esterase (PNAE) catalyses a central reaction by transforming polyneuridine aldehyde into epi-vellosimine, which is the immediate precursor for the synthesis of the ajmalane skeleton. PNAE was purified from cell suspension cultures of Rauvolfia serpentina. The N-terminal sequence and endoproteinase LysC fragments of the purified protein were used for primer design and for the amplification of specific PCR products leading to the isolation of PNAE-encoding cDNA from a R. serpentina library. The PNAE cDNA was fused with a C-terminal His-tag, …