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J Nemcsók

Publications and source records attributed to J Nemcsók.

At least 37 records · Page 2Linked to original sources
PubMed1997

Study of the effects of brief exposure to an organophosphorous insecticide (methidathion) on blood characteristics of carp (Cyprinus carpio).

1. Carp with the dorsal aorta cannulated have been used to study the effects of a 5 hour exposure to methidathion at concentrations of 2 or 6 mg/litre. Blood samples taken during control, exposed and recovery periods were used to determine plasma acetylcholinesterase (AChE) activity, haematocrit value, mean cell volume, total plasma protein, and filtration time through Nucleopore filters containing pores of 8 microns. 2. A drastic inhibition of AChE activity was observed and this continued during the recovery for at least 5 days. Changes in other blood parameters were less marked and recovered soon after fish were returned to non-polluted water. The increased haematocrit and decrease in filtration time suggests some impairment of gas transfer during exposure but the depletion of AChE activity and associated muscular and neural disturbances are more serious results of pollution with this organophosphate insecticide.

Acetylcholinesterase↗
PubMed1995

In vivo effects of deltamethrin exposure on activity and distribution of molecular forms of carp AChE.

The in vivo effects of the insecticide deltamethrin (DM) on the activity and molecular forms of acetylcholinesterase (AChE, EC 3.1.1.7) were examined in different organs (brain, blood serum, heart, liver, and skeletal muscle) of carp. The chosen exposure conditions were a DM concentration of 2 micrograms/liter in the water (12 +/- 1 degrees C) for 3 days. All the treated fish survived the experiment, though the effects of the treatment were very visible: the fish always turned on their side, and the skin/scales became infected during the exposure to DM. DM did not result in a significant change in the AChE activity in any of the studied organs except the blood plasma, where the exposure resulted in an AChE activity decrease of as much as 20%. The ratio of membrane-bound to salt-soluble AChE forms was determined in the control fish. This ratio increased in the sequence heart, skeletal muscle, liver, and brain. The distribution of the AChE molecular forms was studied in the above tissues. The brain and liver contained forms G1, G4, and A12, the heart and skeletal muscle G4, A4, and A12, and the blood serum G1 and G4. The exposure to 2 micrograms/liter DM for 3 days caused hardly any changes in the pattern of the different AChE molecular forms. A small, but significant (P < 0.05) increase in the proportion of the G4 form was observed in the liver, while G1 and A12 decreased by a few percent (but insignificantly). No other tissues investigated exhibited any changes in the distribution of the AChE molecular forms.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholinesterase↗
PubMed1992

The effect of pesticides on carp (Cyprinus carpio L). Acetylcholinesterase and its biochemical characterization.

The activity and molecular forms of acetylcholinesterase (AChE) were characterized in tissues of the carp (Cyprinus carpio). Tissue AChE activity was determined in response to specific inhibitors (ethopropazine, BW 284 C51) or pesticides (CuSO4, paraquat (PQ), methidathion (MD)). The highest AChE activity was found in the serum (878 +/- 100 U/liter), followed by the brain (113 +/- 12 U/liter), heart (89 +/- 6 U/liter), and trunk muscle (35 +/- 5 U/liter). Experiments with specific choline esterase inhibitors revealed a very low amount of pseudocholinesterase in all tissues studied. The ratio of the membrane-bound to the cytoplasmic-free AChE molecular forms was increased in the order of brain, trunk muscle, and heart. In sera of fish treated with MD (2 ppm) there was an 80% inhibition of AChE lasting for 2 weeks. Treatment with CuSO4 or PQ (both 5 ppm) led to a 50% decrease in the serum AChE activity followed by a transient increase over the control level. After 2 weeks of chronic treatment, AChE activity in fish exposed to CuSO4 returned to the control level, whereas in fish treated with PQ an elevated level (130% when compared to the control level) of enzyme activity was found. Our present experimental data indicate that pesticides occurring in natural waters not only inhibit AChE activity in fish but may influence the resynthesis of the enzyme as well.

Acetylcholinesterase↗
PubMed1992

Different sensitivity of the sarcoplasmic reticulum Ca(2+)-ATPase enzyme to fluorescein-isothiocyanate in rabbit and carp muscles.

1. Carp and rabbit sarcoplasmatic reticulum Ca(2+)-ATPase enzymes were compared with respect to their sensitivity to FITC labelling. 2. The carp enzyme showed much lower sensitivity to FITC in the Ca(2+)-Mg2+ activated ATPase activity. Fifty percent inhibition was observed at 20 microM labelling FITC concentration; in rabbit enzyme this inhibition was already achieved at 2 microM FITC. 3. The tryptic cleavage products of the carp enzyme identified with immunoblot analysis as well as with FITC fluorescence, suggest multiple cleavage, yielding different fragments from the ones well known in rabbit and in rat enzyme. 4. The present results indicates major structural differences with respect to the FITC binding, and tryptic cleavage between the SR Ca(2+)-ATPase enzymes from carp and rabbit, despite the cross-reactivity with polyclonal antibodies.

Animals↗
PubMed1989

Structural differences between the Ca2+-ATPase enzymes of sarcoplasmic reticulum membrane from rabbit and carp muscles.

1. Structural features were compared in sarcoplasmic reticulum Ca2+-ATPase enzymes from carp (Cyprinus carpio L.) and rabbit muscles. 2. Both membrane preparations contained the 105,000 mol. wt Ca2+ pump protein in high local density. 3. The tryptic cleavage of the carp enzyme gave different peptide fragments from those observed from rabbit enzyme. 4. Addition of vanadate, Ca2+ or lanthanides did not cause two-dimensional Ca2+-ATPase crystal formation, in contrast to the rabbit enzyme, which forms extensive arrays under these conditions. 5. No differences were found in this respect between microsome preparations derived from warm and cold adapted fishes. 6. A different primary sequence as well as a different disposition of the enzyme in the membrane may stand behind the observed dissimilarities.

Animals↗
PubMed1989

Acetylcholinesterase in the alimentary canal of fish: light and electron microscopic detection, quantitative distribution in different segments of the gut.

The acetylcholinesterase activity was measured and histochemically localized in the alimentary tract of 2 fish species, carp (Cyprinus carpio) and tench (Tinca tinca). A comparison was made of the activities in the different gut segments. Light and electron microscopic histochemistry revealed acetylcholinesterase-positive cell bodies along the entire length of the alimentary canal in both species, between the muscular layers. Acetylcholinesterase-positive, cholinergic motor endplates were frequent in the esophagus of both carp and tench, and they were also present in the striated muscular layers of the tench stomach and midgut. The enzyme activity detected by the method of Ellman et al. (1961) was highest (16.3 U/mg protein) in the tench foregut and midgut, while it was at the same lower level (9.5 U/mg protein) in each segment of the carp gut and in the tench hindgut. The morphological findings and the higher acetylcholinesterase activity in the tench foregut and midgut suggest that the enteric striated musculature is endowed with denser cholinergic innervation than the enteric smooth musculature.

Acetylcholinesterase↗
PubMed1988

Comparison of effects of paraquat and methidation on enzyme activity and tissue necrosis of carp, following exposure to the pesticides singly or in combination.

Under aquarium conditions, treatment with the herbicide paraquat (PQ) and with the insecticide methidation (MD) caused cell damage and stress in carp (Cyprinus carpio L.), as shown by increases in glutamate-dehydrogenase (GIDH, EC 1.4.1.2), glutamate-oxalacetate transaminase (GOT, EC 2.6.1.1) and lactate dehydrogenase (LDH, EC 1.1.1.27) activities and in blood sugar levels. PQ proved synergistic with MD in certain cases as regards the harmful effect exerted. On combined treatment, dilated extracellular spaces were visible by light microscope in the liver, while electronmicroscopic studies revealed signs indicative of cell autolysis in the same organ.

Journal Article↗
PubMed1987

The effect of an organophosphorus pesticide on the enzymes of carp (Cyprinus carpio L.).

1. The effect of 1.5, 2.0 and 5.0 ppm methidation was studied on the ASAT, ALAT, LDH and AChE enzymes, as well as the blood sugar and adrenaline levels in carp. 2. According to our studies methidation implies a potential hazard on the normal biochemical processes of fishes: causing tissue necrosis indicated by the increase ASAT, ALAT and LDH activities, inducing continual stress effect reflected by the increased blood sugar and adrenaline levels, inhibiting AChE activity in the various organs, the consequence under acute effects being fish kill.

Acetylcholinesterase↗
PubMed1986

Neurotransmitter uptake by the central nervous system of fresh-water mussel (Anodonta cygnea L): I. In vitro uptake of serotonin, dopamine and noradrenaline.

The accumulation of serotonin, dopamine and noradrenaline in the cerebral, pedal and visceral ganglia is mediated by a high-affinity (uptake 1) and a low-affinity (uptake 2) system. This uptake mechanism is dependent on time and temperature. The monoamine uptake systems in the cerebral, pedal and visceral ganglia are not identical. At low external serotonin concentration, the cerebral ganglia display twice the rate of uptake 1 as compared to the visceral and pedal ganglia.

Animals↗
PubMed1986

Neurotransmitter uptake by the central nervous system of fresh-water mussel (Anodonta cygnea L): II. Effects of various drugs, amines and ions.

The high-affinity uptakes of serotonin, dopamine and noradrenaline by the cerebral, pedal and visceral ganglia of fresh-water mussel were inhibited by the presence of other amines. Reserpine was the most potent inhibitor among the drugs tested. Chlorpromazine seemed to be a specific inhibitor of serotonin uptake. It did not affect the accumulation of dopamine and noradrenaline. Ouabain had an inhibitory effect only at relatively high concentrations. Lack of sodium greatly diminished the rates of accumulation of serotonin and dopamine, but had less effect on the uptake of noradrenaline.

Amines↗
PubMed1985

Effect of pesticides on the LDH activity and isoenzyme pattern of carp (Cyprinus carpio L.) sera.

Copper sulphate (CuSO4), paraquat (PQ) and methidathion (MD) all caused tissue necrosis as demonstrated by increased levels of lactate dehydrogenase (LDH, EC 1.1.1.27) in blood sera. The main target of damage is shown by the isoenzymes appearing in the blood sera. The CuSO4 treatment damaged mainly the heart and skeletal muscles. This is indicated by the increased LDH level and the M and H subunits appearing in the isoenzyme pattern of the serum. PQ damaged first of all the gills and methidathion had an effect on the skeletal muscles.

Animals↗
PubMed1983

Studies on the effect of paraquat on glycogen mobilization in liver of common carp (Cyprinus carpio L.).

1. A herbicide, paraquat (1,1'dimethyl-4,4'-bipyridilium-dichloride) was administered to carp in 0.5-10.0 ppm concentrations, respectively, and blood sugar level, glucose-6-phosphatase and glycogen phosphorylase activities of liver were determined. 2. Paraquat treatment caused an increase of blood sugar level and enhanced phosphorylase and glucose-6-phosphatase activities. 3. Paraquat can induce alterations in endoplasmic reticulum that might contribute to the changes in glucose-6-phosphatase activity, resulting in an increase of blood glucose level and/or all the effects can be attributed to a high level of circulating epinephrine produced by paraquat toxicosis.

Animals↗
PubMed1983

Morphological and biochemical studies on liver, kidney and gill of fishes affected by pesticides.

Effect of a herbicide, paraquat (1,1'-dimethyl-4,4'-bipyridilium-dichloride), the fungicide copper sulphate, and zinc chloride was studied on the histological structure of liver, kidney and gill of three fish species with different feeding habits, viz.: a herbivorous, silver carp (Hypophthalmichthys molitrix); an omnivorous, common carp (Cyprinus carpio L.) and a carnivorous, sheatfish (Silurus glanis L.). The organs were studied electron microscopically after fixation according to Karnovsky. The toxic effect manifested itself characteristically on the respective species, regardless of the type of the chemical applied and the species specificity. Upon the effect of the treatments applied the cytoplasm of the respiratory cells of the gill became electron transparent and the cytoplasmic organelles disappeared almost totally. In the chloride cells showing focal necrosis, residuals of nuclear, mitochondrial and endoplasmic origin were seen. Pillar cells and the pericytes remained intact. In the nucleus of the liver cells, electron dense heterochromatin was not present. The degree of the damage in the liver cells was indicated by swollen mitochondria with electron transparent matrix and by dilatation and vacuolation of the endoplasmic reticulum system. Epithelial cells decreased in electron density, the endoplasmic reticulum was vesiculated, mitochondria were swollen. Leucocytes increased in number, and empty vacuoles and vacuoles filled with dense granules appeared in them during toxicosis. Copper sulphate or paraquat increased serum transaminase enzyme activities (glutamic acid-oxalacetic acid transaminase, glutamic acid-pyruvic acid transaminase) in all the three fish species. These damages can cause serious disturbances in energy uptake and secretion processes of fish.

Alanine Transaminase↗