Search results for "Gene Expression"
showing 10 items of 4085 documents
Time- and concentration-dependent metabolic and genomic responses to exposure to resin acids in brown trout (Salmo trutta m. lacustris)
2006
The presence of metabolically conjugated resin acids (RAs) in the bile is considered to be a sensitive indicator for exposure of fish to pulp and paper industry effluents; however, to our knowledge, no comprehensive kinetic study of this response has been made. Juvenile brown trout (Salmo trutta m. lacustris) were exposed to a waterborne mixture of seven RAs (wood rosin) in time (0.1-192.0 h; average concentration, 8 microg/L) and dose (average concentrations, 0, 0.6, 4, 14, and 78 microg/L; 10 d) series, and total RAs were analyzed in bile. In time-dependent exposure, total RAs in bile increased up to 24 h. In concentration-dependent exposure, RAs increased along with the concentration of …
Biochemistry and cell biology of silica formation in sponges
2003
The main inorganic material forming the skeletal elements in Demospongiae as well as in Hexactinellida, the spicules, is amorphous silica. The spicules occur in the cytoplasm and the extracellular space and also in the nucleus (as silicate crystals) of some sponge cells; the function in the latter compartment is unknown. Recent evidence shows that the formation of spicules is mediated by the enzyme silicatein. The cDNA as well as the gene encoding this enzyme was cloned from Suberites domuncula. The recombinant silicatein catalyzes the syn- thesis of amorphous silicate using tetraethoxysilane as substrate. The enzyme is dependent on ferric iron. Silicatein also has proteolytic (cathepsin-li…
REGULATION OF CATIONIC AMINO ACID TRANSPORT: The Story of the CAT-1 Transporter
2004
▪ Abstract The discovery of the function of the receptor for the ecotropic retrovirus as a membrane transporter for the essential amino acids lysine and arginine was a landmark finding in the field of molecular nutrition. This finding indicated that cationic amino acid transporters (CATs) act pathologically as viral receptors. The importance of this transporter was further supported by knockout mice that were not viable after birth. CAT-1 was the first amino acid transporter to be cloned; several other CATs were later characterized biochemically and molecularly. These transporters mediate the bidirectional transport of cationic amino acids, thus supporting important metabolic functions, s…
A pea nuclear protein that is induced by dehydration belongs to the vicilin superfamily
2000
The purification to homogeneity of p16, a protein with an electrophoretic mobility compatible with an apparent molecular mass of 16 kDa, from nuclei of ungerminated pea embryonic axes is described. A cDNA clone of its gene, which was designated psp54, was also isolated. The psp54 cDNA contains an open reading frame coding for a 54.4-kDa polypeptide (p54). p16 corresponds to the C-terminal third of p54, although the mechanisms by which the primary polypeptide could be processed are not yet known. The sequence of p54 is 60% identical with that of the precursor of a sucrose-binding soybean protein, and, to a lesser extent (31-34%), it shares homology with some storage proteins. p16 is also 30%…
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…