scholarly journals Anguillicola crassus Infection Significantly Affects the Silvering Related Modifications in Steady State mRNA Levels in Gas Gland Tissue of the European Eel

2016 ◽  
Vol 7 ◽  
Author(s):  
Bernd Pelster ◽  
Gabriel Schneebauer ◽  
Ron P. Dirks
Keyword(s):  
Steady State ◽  
European Eel ◽  
Mrna Levels ◽  
Anguillicola Crassus ◽  
Gland Tissue ◽  
Gas Gland

Determinants of intracellular pH in gas gland cells of the swimbladder of the European eel Anguilla anguilla

2002 ◽  
Vol 205 (8) ◽  
pp. 1069-1075 ◽  
Author(s):  
E. Sötz ◽  
H. Niederstätter ◽  
B. Pelster
Keyword(s):  
Steady State ◽  
Anion Exchange ◽  
Intracellular Ph ◽  
Specific Inhibitor ◽  
Anguilla Anguilla ◽  
Extracellular Ph ◽  
European Eel ◽  
Pulse Technique ◽  
Gland Cells ◽  
Gas Gland

SUMMARY Gas gland cells of the European eel (Anguilla anguilla) were cultured on collagen-coated coverslips, and intracellular pH was measured using the pH-sensitive fluorescent probe 2′,7′-bis-(2-carboxypropyl)-5-(6)-carboxyfluorescein (BCPCF). The contributions of various proton-translocating mechanisms to homeostasis of intracellular pH (pHi) were assessed by adding specific inhibitors of the various proton-translocating mechanisms at a constant extracellular pH (pHe)of 7.4 and after artificial acidification of the cells using the ammonium pulse technique. The greatest decrease in pHi was observed after addition of 5-(N-ethyl-N-isobutyl)-amiloride (MIA), an inhibitor of Na+/H+ exchange. Na+/H+ exchange was active under steady-state conditions at an extracellular pH of 7.4, and activity increased after intracellular acidification. Incubation of gas gland cells with 4,4′-diisothiocyanostilbene-2,2′-disulphonic acid(DIDS), an inhibitor of anion exchange, also caused a decrease in pHi, but this decrease was not as pronounced as in the presence of MIA. Furthermore, at low pHi, the effect of DIDS was further reduced, suggesting that bicarbonate-exchanging mechanisms are involved in maintaining a steady-state pHi but that their importance is reduced at low pH. Bafilomycin A1,a specific inhibitor of the V-ATPase, had no effect on steady-state pHi. However, recovery of intracellular pH after an artificial acid load was significantly impaired in the presence of bafilomycin. Our results suggest that Na+/H+ exchange and anion exchange are important for the regulation of pHi at alkaline values of pHe. When pHi is low, a situation probably often encountered by gas gland cells during gas secretion,Na+/H+ exchange continues to play an important role in acid secretion and a V-ATPase appears to contribute to proton secretion.

scholarly journals Metabolism of the Perfused Swtmbladder of the European EEL: Oxygen, Carbon Dioxide, Glucose and Lactate Balance

1989 ◽  
Vol 144 (1) ◽  
pp. 495-506 ◽  
Author(s):  
B. PELSTER ◽  
H. KOBAYASHI ◽  
P. SCHEID
Keyword(s):  
Lactate Production ◽  
Anguilla Anguilla ◽  
Co2 Production ◽  
European Eel ◽  
Fick Principle ◽  
Partial Pressures ◽  
Gland Tissue ◽  
Arterial Inflow ◽  
Co2 Washout ◽  
Gas Gland

We have measured the metabolic activity in the vascularly isolated, salineperfused swimbladder of the eel (Anguilla anguilla) in order to investigate the pathways for CO2 formation in the gas gland tissue. Concentrations of O2, CO2, glucose and lactate were measured in the arterial inflow and venous outflow of the swimbladder, and metabolic rates were calculated by the direct Fick principle. 1. Total CO2 production, averaging 55.8nmol min−1, was about 4.6 times the O2 consumption (mean 12.0nmol min−1). This suggests that only about 22% of the CO2 is formed by aerobic glucose metabolism. 2. CO2 formation from HCO3− or CO2 washout does not appear to be significant in our experiments with steady perfusion of a saline containing a low level of HCO3−. 3. The ratio of lactate production to glucose uptake averaged 1.2, indicating that only 60% of the glucose is converted to lactate. Since only 1–2% of the glucose was found to be oxidized (2 nmol min−1), the extra glucose appears to be anoxidatively metabolized to CO2. 4. The anoxidative CO2 formation appears to be of functional importance for producing the high gas partial pressures of both CO2 and O2 which are required for secretion of these gases into the swimbladder.

Effects of experimental infections with different doses of Anguillicola crassus (Nematoda, Dracunculoidea) on European eel (Anguilla anguilla)

Aquaculture ◽  
1996 ◽  
Vol 141 (1-2) ◽  
pp. 41-57 ◽  
Author(s):  
O.L.M. Haenen ◽  
T.A.M. van Wijngaarden ◽  
M.H.T. van der Heijden ◽  
J. Höglund ◽  
J.B.J.W. Cornelissen ◽  
...  
Keyword(s):  
Anguilla Anguilla ◽  
European Eel ◽  
Experimental Infections ◽  
Anguillicola Crassus ◽  
Different Doses

scholarly journals Genomic structure of murine methylmalonyl-CoA mutase: evidence for genetic and epigenetic mechanisms determining enzyme activity

1993 ◽  
Vol 296 (3) ◽  
pp. 663-670 ◽  
Author(s):  
M F Wilkemeyer ◽  
E R Andrews ◽  
F D Ledley
Keyword(s):  
Enzyme Activity ◽  
Steady State ◽  
Transcription Initiation ◽  
Cultured Cells ◽  
Genomic Structure ◽  
Genetic Regulation ◽  
Regulatory Elements ◽  
Transcription Unit ◽  
Mrna Levels ◽  
Sequence Motifs

Methylmalonyl-CoA mutase (MCM) is a nuclear-encoded mitochondrial matrix enzyme. We have reported characterization of murine MCM and cloning of a murine MCM cDNA and now describe the murine Mut locus, its promoter and evidence for tissue-specific variation in MCM mRNA, enzyme and holo-enzyme levels. The Mut locus spans 30 kb and contains 13 exons constituting a unique transcription unit. A B1 repeat element was found in the 3′ untranslated region (exon 13). The transcription initiation site was identified and upstream sequences were shown to direct expression of a reporter gene in cultured cells. The promoter contains sequence motifs characteristic of: (1) TATA-less housekeeping promoters; (2) enhancer elements purportedly involved in co-ordinating expression of nuclear-encoded mitochondrial proteins; and (3) regulatory elements including CCAAT boxes, cyclic AMP-response elements and potential AP-2-binding sites. Northern blots demonstrate a greater than 10-fold variation in steady-state mRNA levels, which correlate with tissue levels of enzyme activity. However, the ratio of holoenzyme to total enzyme varies among different tissues, and there is no correlation between steady-state mRNA levels and holoenzyme activity. These results suggest that, although there may be regulation of MCM activity at the level of mRNA, the significance of genetic regulation is unclear owning to the presence of epigenetic regulation of holoenzyme formation.

Influence of environmental enrichment on steady-state mRNA levels for EAAC1, AMPA1 and NMDA2A receptor subunits in rat hippocampus

2007 ◽  
Vol 1174 ◽  
pp. 18-27 ◽  
Author(s):  
Josefine Andin ◽  
Martin Hallbeck ◽  
Abdul H. Mohammed ◽  
Jan Marcusson
Keyword(s):  
Steady State ◽  
Environmental Enrichment ◽  
Rat Hippocampus ◽  
Mrna Levels

Quantitative assessment of ground squirrel mRNA levels in multiple stages of hibernation

2002 ◽  
Vol 10 (2) ◽  
pp. 93-102 ◽  
Author(s):  
L. Elaine Epperson ◽  
Sandra L. Martin
Keyword(s):  
Steady State ◽  
Core Body Temperature ◽  
Ground Squirrels ◽  
Apolipoprotein A1 ◽  
Mrna Levels ◽  
Cdna Subtraction ◽  
Global Issues ◽  
Α2 Macroglobulin ◽  
Steady State Levels ◽  
Molecular Components

Hibernators in torpor dramatically reduce their metabolic, respiratory, and heart rates and core body temperature. These extreme physiological conditions are frequently and rapidly reversed during the winter hibernation season via endogenous mechanisms. This phenotype must derive from regulated expression of the hibernator’s genome; to identify its molecular components, a cDNA subtraction was used to enrich for seasonally upregulated mRNAs in liver of golden-mantled ground squirrels. The relative steady-state levels for seven mRNAs identified by this screen, plus five others, were measured and analyzed for seasonal and stage-specific differences using kinetic RT-PCR. Four mRNAs show seasonal upregulation in which all five winter stages differ significantly from and are higher than summer (α2-macroglobulin, apolipoprotein A1, cathepsin H, and thyroxine-binding globulin). One of these mRNAs, α2-macroglobulin, varies during the winter stages with significantly lower levels at late torpor. None of the 12 mRNAs increased during torpor. The implications for these newly recognized upregulated mRNAs for hibernation as well as more global issues of maintaining steady-state levels of mRNA during torpor are discussed.

scholarly journals Triosephosphate isomerase deficiency: consequences of an inherited mutation at mRNA, protein and metabolic levels

2005 ◽  
Vol 392 (3) ◽  
pp. 675-683 ◽  
Author(s):  
Judit Oláh ◽  
Ferenc Orosz ◽  
László G. Puskás ◽  
László Hackler ◽  
Margit Horányi ◽  
...  
Keyword(s):  
Steady State ◽  
Triosephosphate Isomerase ◽  
Specific Activity ◽  
Energy State ◽  
Dihydroxyacetone Phosphate ◽  
Peptidase Activity ◽  
Mrna Levels ◽  
Regulatory Enzymes ◽  
Computational Data ◽  
Fructose 1,6 Bisphosphate

Triosephosphate isomerase (TPI) deficiency is a unique glycolytic enzymopathy coupled with neurodegeneration. Two Hungarian compound heterozygote brothers inherited the same TPI mutations (F240L and E145Stop), but only the younger one suffers from neurodegeneration. In the present study, we determined the kinetic parameters of key glycolytic enzymes including the mutant TPI for rational modelling of erythrocyte glycolysis. We found that a low TPI activity in the mutant cells (lower than predicted from the protein level and specific activity of the purified recombinant enzyme) is coupled with an increase in the activities of glycolytic kinases. The modelling rendered it possible to establish the steady-state flux of the glycolysis and metabolite concentrations, which was not possible experimentally due to the inactivation of the mutant TPI and other enzymes during the pre-steady state. Our results showed that the flux was 2.5-fold higher and the concentration of DHAP (dihydroxyacetone phosphate) and fructose 1,6-bisphosphate increased 40- and 5-fold respectively in the erythrocytes of the patient compared with the control. Although the rapid equilibration of triosephosphates is not achieved, the energy state of the cells is not ‘sick’ due to the activation of key regulatory enzymes. In lymphocytes of the two brothers, the TPI activity was also lower (20%) than that of controls; however, the remaining activity was high enough to maintain the rapid equilibration of triosephosphates; consequently, no accumulation of DHAP occurs, as judged by our experimental and computational data. Interestingly, we found significant differences in the mRNA levels of the brothers for TPI and some other, apparently unrelated, proteins. One of them is the prolyl oligopeptidase, the activity decrease of which has been reported in well-characterized neurodegenerative diseases. We found that the peptidase activity of the affected brother was reduced by 30% compared with that of his neurologically intact brother.

Sign in / Sign up

Export Citation Format

Share Document