Metallothionein induction by nonsteroidal antiinflammatory drugs

In the present study we report on the effects of commonly used nonsteroidal antiinflammatory drugs on metallothionein (MT) and MT-I mRNA levels. A single dose of chloroquine (100 mg/kg), diclofenac (100 mg/kg), indomethacin (10 mg/kg), or piroxicam (100 mg/kg) was administered ip to C57B1 mice. After 18 h, MT levels were determined with a Cd-saturation radioassay. MT-I mRNA levels were measured by Northern Blot analyses using a probe containing the mouse MT-I gene. All drugs tested caused an increase in the MT content of the liver but not of the kidneys and lung. The lowest and highest effects were observed with chloroquine (8 times the control value) and diclofenac (18 times), respectively. In accordance with the stimulation of MT synthesis, increased accumulation of hepatic MT-I mRNA could be demonstrated. These results indicate that elevated MT levels may contribute to the effectiveness of nonsteroidal antiinflammatory drugs in the treatment of rheumatoid arthritis (RA).     

Androgen receptor heterogeneity in LNCaP cells is caused by a hormone independent phosphorylation step

Androgen receptor synthesis and modification were studied in the human LNCaP cell line. Immunoblotting showed that the androgen receptor migrated as a closely spaced 110–112 kDa doublet on SDS-PAGE gels. Most of the receptor protein is present in the higher molecular mass form. Labelling experiments with [³⁵S]methionine showed that the androgen receptor is synthesized as a single 110 kDa protein which is rapidly converted to a 112 kDa protein. Upon alkaline phosphatase treatment a gradual elimination of the 112 kDa isoform with a concomitant increase of the 110 kDa isoform was seen, indicating that the observed 110 to 112 kDa upshift reflects androgen receptor phosphorylation. Furthermore, it is shown that both isoforms can bind hormone and undergo a hormone dependent transformation to a tight nuclear binding form, indicating that the 110 to 112 kDa conversion is not an obligatory step for hormone binding or receptor transformation.     

Density dependent mortality in the springtail species Orchesella cincta due to predation by the carabid beetle Notiophilus biguttatus

Mortality of the collembole species Orchesella cincta (L.), due to predation by the carabid Notiophilus biguttatus F., has been measured in the laboratory at three levels of prey density. Prey densities were chosen such that the predator's consumption at the lowest prey density was a little above the maintenance ration. Between the two lowest prey densities, mortality increased significantly with prey density. We presume that density-dependent search activity by the predator is responsible for the positive density-dependent mortality. A method is proposed to solve the problem of decreasing prey density during the observations.

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Relation positive entre la densité de Orchesella cincta et la mortalité due à la prédation part Nothiophilus biguttarus

Résumé Cet article décrit l'importance de la prédation par le carabe N. biguttatus en fonction de la densité de la proie, O. cincta. Les résultats montrent que, sous l'effet de la prédation, la mortalité de la proie augmente avec sa densité. La quantité minimale de proies qui doit être consommée pour permettre la reproduction du carabe, a été déterminée. La relation entre la fécondité du carabe et l'effectif consommé, montre l'effet stabilisant de la prédation sur les populations de proies.La relation de dépendance de la densité observée avec la mortalité est due à une modification du comportement du carabe en fonction de la densité de sa proie. Nous proposons un modèle permettant de prévoir la régression de la population de proies sous les effets de la prédation.

     

Ultrastructure of intestinal and gall-bladder epithelium in the teleost Gasterosteus aculeatus L., as related to their osmoregulatory function

Summary Intestinal and gall-bladder epithelial cells in sticklebacks have been examined in ultrathin sections and freeze-etch replicas. Enterocytes throughout the intestine appear to have a well-developed basal labyrinth similar to that of renal tubular cells, consisting of baso-lateral infoldings closely associated with numerous mitochondria. The lumen inside these intracellular membranes is continuous with the intercellular space via pores. Such a membrane system is also present in the epithelial cells lining the gall bladder, distinguishing them from gall-bladder cells of higher vertebrates. Morphometric analysis indicates that the basal labyrinth of enterocytes in the posterior part of the intestine increases markedly in both sexually mature males and androgen-treated females. This does not occur in the anterior part or gall bladder. In sticklebacks, androgens cause reduced urine excretion and enhanced fluid release via the anus. We conclude that the cells lining the intestine and gall bladder possess an extensive basal labyrinth that may function as a backward channel system, enabling fluid to be produced in the intestine of fish. The androgen-induced increase in the extent of the basal labyrinth in the posterior part of the intestine may be related to the enhanced rate of intestinal fluid excretion observed in sexually mature male sticklebacks.     

Arginine catabolism in the cotyledons of developing and germinating pea seeds

Arginine is the predominant free amino acid in the cotyledons of developing seeds of Pisum sativum L. cv Marzia. Breakdown of arginine was measured by injecting l-[guanido-¹⁴C]arginine into detached cotyledons. Cotyledons of developing seeds showed a low rate of ¹⁴CO₂ evolution whereas a much higher rate of ¹⁴CO₂ evolution was measured from cotyledons of seeds 4 days after the onset of germination. The activities of the catabolic enzymes arginase, urease, and ornithine aminotransferase were measured throughout development and germination. Arginase and ornithine aminotransferase were present at an early stage of development. Urease activity appeared later as the seeds started to desiccate. During germination, all three enzymes were present. The different course of activity of these enzymes indicates that they are controlled separately.     

Carbohydrate analysis of water-soluble uronic acid-containing polysaccharides with high-performance anion-exchange chromatography using methanolysis combined with TFA hydrolysis is superior to four other methods.

Sulfuric acid hydrolysis according to the Saeman procedure, TFA hydrolysis, and methanolysis combined with TFA hydrolysis were compared for the hydrolysis of water-soluble uronic acid-containing polysaccharides originating from fungi, plants, and animals. The constituent sugar residues released were subsequently analyzed by either conventional GLC analysis of alditol acetates or high-performance anion-exchange chromatography with pulsed-amperometric detection. It was shown that TFA hydrolysis alone is not sufficient for complete hydrolysis. Sulfuric acid hydrolysis of these polysaccharides resulted in low recoveries of 6-deoxy-sugar residues. Best results were obtained by methanolysis combined with TFA hydrolysis. Methanolysis with 2 M HCl prior to TFA hydrolysis resulted in complete liberation of monosaccharides from pectic material and from most fungal and animal polysaccharides tested. Any incomplete hydrolysis could be assessed easily by HPAEC, by the detection of characteristic oligomeric products, which is difficult using alternative methods currently in use. Methanolysis followed by TFA hydrolysis of 20 micrograms water-soluble uronic acid containing polysaccharides and subsequent analysis of the liberated sugar residues by HPAEC allowed us to determine the carbohydrate composition of these polysaccharides rapidly and accurately in one assay without the need for derivatization.     

Molecular analysis of a pistil-specific gene expressed in the stigma and stylar cortex of Solanum tuberosum

A gene, sts14, coding for a highly expressed mRNA in pistils of Solanum tuberosum, was isolated. Northern blot and in situ analyses demonstrated that the gene was expressed throughout pistil development in both the stylar cortex and the stigma. The deduced STS14 protein displays similarity to the pathogenesis-related PR-1 proteins. A possible function for protection or guidance of the pollen tubes through the pistil is discussed.     

Changes in glomerular structure after sexual maturation and seawater adaptation in males of the euryhaline teleost Gasterosteus aculeatus L.

Summary In sexually mature male sticklebacks, the renal tubular cells are transformed from ion reabsorbing to mucus secreting cells and in these fish concomitant changes take place in the glomeruli.The present study compares glomerular structure of immature males in fresh water (controls) to those of mature males in fresh water and to immature male sticklebacks in seawater. Glomerular structure is markedly altered in the latter two groups and the changes are similar to a large extent. In these two groups the renal capsules and glomeruli are smaller and the lumina of the glomerular capillaries decrease in diameter, while the number and size of the endothelial fenestrations are reduced. Mesangial cells proliferate and the mesangial matrix greatly expands in both the centrolobular region and the subendothelial space around the capillaries. The secretory activity of the podocytes is enhanced and is responsible for the observed increase in thickness of the outer layer of the basal lamina, the lamina rara externa. The area covered by the filtration slit membranes is reduced, probably as a consequence of fusion of the pedicels of the podocytes. The permeability characteristics of the glomerular filtration barrier for macromolecules, as studied with ferritin injections, remain unaltered. However, the observed differences point to a reduction of the glomerular filtration rate (GFR) during maturation in male sticklebacks, as well as during adaptation of sticklebacks to seawater. This conclusion is in line with physiological evidence.     

Redox-Dependent Control of FOXO/DAF-16 by Transportin-1

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Highlights? FOXO forms redox-sensitive, disulfide-dependent complexes with several proteins ? Transportin-1 binds to FOXO via a disulfide and regulates its nuclear localization ? Redox and insulin signaling govern FOXO nuclear localization via distinct pathways ? Redox control of longevity protein FOXO/DAF-16 is evolutionarily conserved