Influence of roundup herbicide on the activities of peptidases in the intestines of various fish species

It has been revealed that, as a rule, Roundup herbicide inhibits activities of peptidases in the intestine mucosa and chyme in various fish species, both benthivorous (common carp Cyprinus carpio, silver bream Blicca bjoerkna, roach Rutilus rutilus, and crucian carp Carassius carassius) and piscivorous (perch Perca fluviatilis, pike Esox lucius, and sander Sander lucioperca). The tolerance of peptidases to the herbicide is species-specific. The magnitude and vector of the effects of Roundup depend on its concentration and localization of an enzyme. In the mucosa, the enzymes of common carp and pike are most tolerant, while the enzymes of common carp, silver bream, and pike are most tolerant in the chyme.     

Distribution of peptidase activity in teleost and rat tissues

Peptides play important roles in cell regulation and signaling in many tissues. The actions of peptides are regulated by peptidases. Although the activity of these enzymes has been thoroughly characterized in mammals, little is known about their presence or function in fish. In the present study, we compared the activity of several peptidases in selected tissues (pituitary gland, different brain areas, kidney and gills) of the gilthead sea bream and rainbow trout with that found in similar rat tissues (lungs studied in place of gills). Soluble puromycin-sensitive aminopeptidase showed the highest values in the pituitary gland of the sea bream, whereas the membrane-bound form was found to be more active in the trout kidney. Very high levels of activity of aminopeptidase N were detected in trout and sea bream plasma. In contrast, the highest levels of activity of aminopeptidase B were found in rat tissues, with the exception of the gills of the trout. Aminopeptidase N levels tended to be higher in sea bream tissues with respect to those of trout. In contrast, the level of activity of aminopeptidase B was found to be consistently much higher in trout tissues than in those of the sea bream. Prolyl endopeptidase activity was principally detected in the pituitary gland and in the brain areas of teleosts. These differences between species could be related to different mechanisms of osmoregulation in saltwater- and in freshwater-adapted fish.     

Effects of heavy metals (Cu and Zn) on digestive glycosidases in benthivorous fish of areas of Rybinsk Reservoir differing in anthropogenic loads

The separate and combined in vitro effects of heavy metal ions (Cu and Zn) at concentrations of 0.1–25 mg/L on the activities of maltase, sucrase, and amylolytic activity in the intestines of bream and roach caught in areas of the Rybinsk Reservoir differing in anthropogenic loads have been studied. In fish from the polluted Sheksninskii Reach, membrane maltase and sucrase enzymes are less sensitive to the effects of Cu and Zn ions than in fish from the relatively clean Volzhskii Reach. On the other hand, starch-hydrolyzing enzymes were more sensitive to the effects of the metals under study in bream from a polluted area, which was especially evident in summer. The combined effect of Cu and Zn ions (1: 1) in most cases weakens the separate effects of these metals on the activities of hydrolases (except for amylolytic activity) in the studied fish.     

Sensitivity to vinyl phenol derivatives produced by phenolic acid decarboxylase activity in Escherichia coli and several food-borne Gram-negative species

Ferulic, p-coumaric, and caffeic acids are phenolic acids present in soil, food, and gut, which have antimicrobial effects. Some Gram (+) bacteria metabolize these phenolic acids into vinyl derivatives due to phenolic acid decarboxylase activity (PAD) involved in the phenolic acid stress response (PASR). In this study, the antimicrobial activity of phenolic acids and their vinyl derivatives was tested on a panel of desirable and undesirable food-borne bacteria, especially Gram (?) species of Salmonella, Enterobacter, Klebsiella, and Pseudomonas, most of them without PAD activity. Native and engineered Escherichia coli strains either expressing or not PAD activity were included. Gram (?) bacteria of the panel were not significantly inhibited by phenolic acids at 3 mM, but were dramatically inhibited by the corresponding vinyl derivatives. On the contrary, Gram (+) bacteria displaying the PASR face the toxicity of phenolic acids by PAD activity and are not inhibited by vinyl phenols. In E. coli, the genes aaeB and marA, encoding efflux pumps for antimicrobial compounds, are upregulated by the addition of p-coumaric acid, but not by its derivative 4-vinyl phenol (p-hydroxystyrene). These results suggest that phenolic acids and their vinyl phenol derivatives produced by PAD (+) species could have a significant impact on undesirable or pathogenic food-borne Gram (?) bacteria in complex microbial ecosystems.     

Rearing temperature enhances hepatic glucokinase but not glucose-6-phosphatase activities in European sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata) juveniles fed with the same level of glucose

The aim of this work was to elucidate if the previous results observed in hepatic glucokinase (GK) and glucose-6-phosphatase (G6Pase) activities in European sea bass and gilthead sea bream are due to temperature per se or to differences in feed intake at different water temperatures. For that purpose triplicate groups of fish (30 g initial body weight) were kept at 18 degrees C or 25 degrees C during two weeks and fed a fixed daily ration of a glucose-free or 20% glucose diet. At the end of the experimental period, plasma glucose levels in both species were not influenced by water temperature but were higher in fish fed the glucose diet. Higher hepatic GK activity was observed in the two fish species fed the glucose diet than the glucose-free diet. In the glucose fed groups, GK activity was higher at 25 degrees C than at 18 degrees C. Glucose-6-phosphatase activities in both species were not influenced by water temperature. In European sea bass and in contrast to gilthead sea bream it was observed an effect of dietary composition on G6Pase activities with surprising higher activities recorded in fish fed the glucose diet than in fish fed the glucose-free diet. Overall, our data strongly suggest that European sea bass and gilthead sea bream are apparently capable to strongly regulate glucose uptake by the liver but not glucose synthesis, which is even enhanced by dietary glucose in European sea bass. Within limits, increasing water temperature enhances liver GK but not G6Pase activities, suggesting that both species are more able to use dietary carbohydrates at higher rearing temperatures.     

Synthetic bioantioxidants--inhibitors of acetylcholinesterase activity]

The inhibitory effects of synthetic antioxidants (3-oxypyridine, pyrimidine and hindered phenols) on the enzymic activity of membrane-bound acetylcholinesterase (AChE) was studied. In terms of estimated kinetic characteristics of AChE-reaction (KM, Vmax, KI), the pattern of enzyme inhibition by the hindered phenol compounds was found to be of non-competitive or mixed type depending on the inhibitor structure or on the substrate acetylcholine or acetylthiocholine used. The comparative study of the inhibitory action of water-soluble derivatives of hindered phenols and fatty-soluble ionol made it possible to reveal possible contributions to the inhibition of both direct and mediated (by the membrane microsurroundings) effects on the membrane-bound AChE by the studied synthetic bioantioxidants.     

Diurnal Dynamics of Activity of Peptidases at Early Ontogenesis of Bleak <Emphasis Type="Italic">Alburnus alburnus</Emphasis> (L.) from Coastal Shallows of the Rybinsk Reservoir

The diurnal dynamics of the activity of peptidases in fish larvae by the example of bleak Alburnus alburnus (L.) as the dominant species in the open and protected shallows of the Rybinsk Reservoir has been studied for the first time. Two peaks of enzyme activity in the intestinal mucosa of fish larvae are revealed: morning and night. The data on species composition and daily dynamics of number of fish larvae in the shallows of different types are presented.     

Acetylcholinesterase and butyrylcholinesterase activities in brain and plasma of freshwater teleosts: cross-species and cross-family differences

Brain and plasma acetylcholinesterase (AChE; EC 3.1.1.7) and plasma butyrylcholinesterase (BChE; EC 3.1.1.8) specific activities were assayed in 16 freshwater teleosts belonging to four families: Cyprinidae, Percidae, Esocidae and Lotidae. Brain AChE activity varied among fish species approximately 15-fold, ranging from 138 to 2011 micromol/g per h. All cyprinids had higher brain AChE activity than other fish families. Plasma AChE activity was on average 100-fold lower than that in brain, varying from 1.2 to 18.6 micromol/ml per h. Plasma BChE activity was found only in cyprinids with the exception of the common and crucian carp, and sabrefish. It varied from 26 to 1083 micromol/ml per h. In bream (Abramis brama) only 30% of specimens studied had BChE activity. The correlation coefficient values between activities of brain and plasma AChE, brain AChE and plasma BChE, plasma AChE and BChE were 0.67, 0.68 and 0.84, respectively. Cross-species and also cross-family differences in AChE and BChE activities among fish were demonstrated. Possible reasons for the differences are discussed.     

Activity of Peptidases and Glycosidases: Effect of Light Deprivation and Heavy Metals on the Effects of Serotonin and Cholecystokinin in the Carp <Emphasis Type="Italic">Cyprinus carpio</Emphasis>

The dependence of the effects of serotonin and cholecystokinin on the activity of peptidases and glycosidases in the intestine of the carp Cyprinus carpio from the content of zinc and copper ions in different photoperiods (6: 18 and 0: 24 h) was studied. It was shown that the activity of enzymes in the intestine of fish under the influence of both hormones in conditions of light deprivation significantly increases, especially under the action of copper. The mechanisms of the influence of these factors on the activity of peptidases and glycosidases of fish intestines are discussed.     

Early effects of phenolic compounds, extracted from two forest litters, on ammonium uptake and assimilation in Pinus laricio and Pinus pinaster seedlings

The early effects of low molecular weight phenolic compounds, released by Pinus laricio and Pinus pinaster litter, on ammonium uptake and its assimilation in two Pinus species were studied. In Pinus laricio seedlings, the exposure to phenols extracted from Pinus laricio litter increased not only the ammonium uptake but also the activity of the main enzymes involved in its assimilation, whereas the phenols extracted from Pinus pinaster litter had a negative effect on these metabolic processes. In Pinus pinaster seedlings, the exposure to both phenols decreased the ammonium uptake and the activity of the main enzymes involved in its assimilation. Histological analysis carried out in Pinus laricio roots showed that phenols extracted from Pinus laricio litter induced the greatest growth of cortex, element through which occurs the ions uptake in plants, whereas phenol extracted from Pinus pinaster litter inhibited cortex development. On the other hand, in Pinus pinaster seedlings the observation showed that both phenols inhibited cortex growth indicating a strict correlation between cortex development and ammonium uptake and its assimilation.     

Modulation of FAD-dependent monooxygenase activity from aromatic compounds-degrading Stenotrophomonas maltophilia strain KB2

The purpose of this study was purification and characterization of phenol monooxygenase from Stenotrophomonas maltophilia strain KB2, enzyme that catabolises phenol and its derivatives through the initial hydroxylation to catechols. The enzyme requires NADH and FAD as a cofactors for activity, catalyses hydroxylation of a wide range of monocyclic phenols, aromatic acids and dihydroxylated derivatives of benzene except for catechol. High activity of this monooxygenase was observed in cell extract of strain KB2 grown on phenol, 2-methylphenol, 3-metylphenol or 4-methylphenol. Ionic surfactants as well as cytochrome P450 inhibitors or 1,4-dioxane, acetone and n-butyl acetate inhibited the enzyme activity, while non-ionic surfactants, chloroethane, ethylbenzene, ethyl acetate, cyclohexane, and benzene enhanced it. These results indicate that the phenol monooxygenase from Stenotrophomonas maltophilia strain KB2 holds great potential for bioremediation.     

Comparative study of acetylcholinesterase and butyrylcholinesterase in brain and serum of several freshwater fish: specific activities and in vitro inhibition by DDVP, an organophosphorus pesticide

A comparative study of specific activities and in vitro inhibition of brain and serum acetylcholinesterase (AChE; EC 3.1.1.7) and serum butyrylcholinesterase (BChE; EC 3.1.1.8) by DDVP, an organophosphorus pesticide, was conducted in 11 freshwater teleost species belonging to four families (Cyprinidae; common carp Cyprinus carpio, bream Abramis brama, blue bream A. ballerus, white bream Blicca bjoerkna, roach Rutilus rutilus, bleak Alburnus alburnus, ide Leuciscus idus; Percidae: perch Perca fluviatilis, pikeperch Stizostedion lucioperca; Esocidae: pike Esox lucius and Coregonidae: whitefish Coregonus albula). Specific AChE and BChE activities in brain and serum of fish were determined. Brain AChE activity varied among fish species approximately 10-fold, ranging from 192.6 to 1353.2 micromol g(-1) h(-1), respectively in perch and whitefish. All cyprinids had higher brain AChE activity than those of other fish families. Serum AChE activity was 100-fold lower than in brain. Serum BChE activity was found only in cyprinids with the exception of the common carp. It varied from 163.8 to 970.3 micromol g(-1) h(-1), respectively in roach and bleak. The bimolecular enzyme inhibition rate constants (kIIs) and pI50) values for DDVP were calculated. Sensitivity of fish AChEs both in brain and serum is similar to those of typical AChEs in mammals. The range of kIIs was 3.4-51.7 x 10(3) mol(-1) 1 min(-1) (pI50s were 5.3-6.5), respectively in white bream and ide. In contrast, fish serum BChE was more sensitive to inhibition than typical BChE and AChE in mammals. Values of kII for BChE were 1.0-2.5 x 10(7) mol(-1) 1 min(-1) (pI50 was 8.8-9.2), respectively in ide and bleak.     

Habitat Use by YOY in the Littoral Zone of an Artificially Heated Reservoir

Both temporal and spatial distributions of a young of the year (YOY) fish community were studied in the littoral zone of a French reservoir. The time survey indicated that littoral occupation highly depends on YOY time of appearance. During late spring and summer, the smallest white bream YOY (L_T < 20 mm) were restricted to complex habitats whereas those of pumpkinseed occupied all available habitats. Growing white bream progressively migrated to open water areas. At that time, pumpkinseed was the only species sampled in abundance in the littoral zone and was still collected in all habitats. The success of the introduction of pumpkinseed might be explained by both its late hatching and its opportunistic strategy in habitat selection enabling it to exploit physical spaces left vacant. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Effects of different fish species and biomass on plankton interactions in a shallow lake

Thirty-six enclosures, surface area 4 m², were placed in Little Mere, a shallow fertile lake in Cheshire, U.K. The effects of different fish species (common carp, common bream, tench and roach) of zooplanktivorous size, and their biomass (0, 200 and 700 kg ha^–1) on water chemistry, zooplankton and phytoplankton communities were investigated. Fish biomass had a strong effect on mean zooplankton size and abundance. When fish biomass rose, larger zooplankters were replaced by more numerous smaller zooplankters. Consequently phytoplankton abundance rose in the presence of higher densities of zooplanktivorous fish, as zooplankton grazing was reduced. Fish species were also significant in determining zooplankton community size structure. In enclosures with bream there were significantly greater densities of small zooplankters than in enclosures stocked with either carp, tench and, in part, roach. When carp or roach were present, the phytoplankton had a greater abundance of Cyanophyta than when bream or tench were present. Whilst top-down effects of fish predation controlled the size partitioning of the zooplankton community, this, in turn apparently controlled the bottom-up regeneration of nutrients for the phytoplankton community. At the zooplankton–phytoplankton interface, both top-down and bottom-up processes were entwined in a reciprocal feedback mechanism with the extent and direction of that relationship altered by changes in fish species. This has consequences for the way that top-down and bottom-up processes are generalised.     

Causes and consequences of the success of bream in Dutch eutrophic lakes

In the last decennia eutrophication has caused a shift in the species composition of fish communities in Dutch fresh waters. The changes have led to the disappearance of vegetation in lakes and ponds; zooplankton and chironomids are now the most abundant food organisms for fish. In the turbid, open waters bream and pikeperch are the dominant fish species. Only small bream is vulnerable to predation, but because bream grows much faster than the other cyprinids the time span in which the fish is vulnerable is the shortest. The large bream (>20 cm) can coexist with pikeperch since it is not vulnerable to predation and still utilizes the food organisms efficiently. Eutrophication is accelerated if both bream populations are composed of small-sized specimens preventing large-sized zooplankton to develop, and if they are composed of large-sized individuals which can efficiently stir up the bottom sediments.     

Degradation of mixtures of phenolic compounds by <Emphasis Type="Italic">Arthrobacter chlorophenolicus</Emphasis> A6

In this study the chlorophenol-degrading actinobacterium, Arthrobacter chlorophenolicus A6, was tested for its ability to grow on mixtures of phenolic compounds. During the experiments depletion of the compounds was monitored, as were cell growth and activity. Activity assays were based on bioluminescence output from a luciferase-tagged strain. When the cells were grown on a mixture of 4-chlorophenol, 4-nitrophenol and phenol, 4-chlorophenol degradation apparently was delayed until 4-nitrophenol was almost completely depleted. Phenol was degraded more slowly than the other compounds and not until 4-nitrophenol and 4-chlorophenol were depleted, despite this being the least toxic compound of the three. A similar order of degradation was observed in non-sterile soil slurries inoculated with A. chlorophenolicus. The kinetics of degradation of the substituted phenols suggest that the preferential order of their depletion could be due to their respective pKa values and that the dissociated phenolate ions are the substrates. A mutant strain (T99), with a disrupted hydroxyquinol dioxygenase gene in the previously described 4-chlorophenol degradation gene cluster, was also studied for its ability to grow on the different phenols. The mutant strain was able to grow on phenol, but not on either of the substituted phenols, suggesting a different catabolic pathway for the degradation of phenol by this microorganism.     

Dynamics and the state of fishery resources in the Rybinsk Reservoir from 1950–2010

Data on dynamics of the main commercial fish populations in the Rybinsk Reservoir over the period of 1950–2010 have been generalized. Fishing intensity is the main factor that determines the state of fish resources. It affects not only the abundance of commercial fish but also determines changes in population characteristics, i.e., changes in age and size structure and increase in the portion of young individuals. The effect of fishing on populations of some species depends on their commercial value. Commercial fishing affects notably such species as bream Abramis brama, zander Sander lucioperca, and pike Esox lucius. Commercial fishing affects, to a lesser extent, populational characteristics of such mass fish species as roach Rutilus rutilus and blue bream Abramis ballerus whose commercial value is lower.     

氨氮胁迫下不同食性鱼类仔鱼抗氧化和非特异性免疫的差异响应

为探究氨氮胁迫对不同食性鱼类的影响,研究选取不同食性的4种鱼类(鲢Hypophthalmichthys molitrix、草鱼Ctenopharyngodon idella、团头鲂Megalobrama amblycephala和黄颡鱼Pelteobagrus fulvidraco)仔鱼为研究对象,探讨不同浓度氨氮(0、1、2和3 mg/L)短期胁迫(96h)对其生长、抗氧化和非特异性免疫响应的影响及其分子机制。结果显示:(1)氨氮胁迫导致4种仔鱼的体长生长速度呈现剂量依赖性减缓;(2)不同浓度氨氮导致4种仔鱼体内T-AOC、CAT和GPx含量显著降低(P<0.05), 2和3 mg/L氨氮暴露显著降低了草鱼、团头鲂和黄颡鱼仔鱼体内SOD活力(P<0.05),仅检测到黄颡鱼gpx及鲢sod转录水平出现显著性下调(P<0.05);(3)在不同浓度氨氮胁迫下, 4种仔鱼相关免疫基因转录水平均呈现一定的上调,仅鲢il1β转录水平显著下降(P<0.05),相对地草鱼仔鱼LYZ含量显著性下降,黄颡鱼仔鱼LYZ含量在2 mg/L氨氮组显著性上升(P<0.05)。双因素...     

Changes of the serotonergic system activity in fish tissues during an increase of water salinity

Changes of environment parameters produce essential effects on the serotonergic system activity in the body tissues. This paper describes study of the serotonergic system activity in various tissues of half-migratory fish—the Caspian roach Rutilus rutilus caspicus and the bream Abramis brama orientalis—caught in the fresh and brackish water. Using the method of indirect solid-phase ELISA test, the serotonergic system activity was assessed by determining in the studied fish tissues of the amount of serotonin-modulating anticonsolidation protein (SMAP) that is in the linear correlation with serotonin level. A significant change of the SMAP level in the Caspian roach and bream brain was found under effect on increased water salinity. Analysis of the SMAP amount in the bream liver did not reveal any differences in the animals caught in the brackish and fresh water. At the same time, in the bream gill there was a small rise of the SMAP content in the fish caught in the brackish water. The revealed in this experiment elevation of the SMAP amount in the Caspian roach and bream brain reflecting a corresponding increase of the serotonergic system activity indicates involvement of adaptive readjustments in the animal body.     

Training fish for restocking: refuge and predator training in the hatchery has limited benefits for a marine fish

Large numbers of hatchery-reared fish are released in stocking programmes; however, success is limited by high mortality. Predation is seen as the main cause of deaths but might be reduced by training fish before release to avoid predators and/or use refuge. In this study on a potential restocking species, yellowfin bream Acanthopagrus australis, the effects of predator training and refuge on the behaviour of fish in the hatchery were tested. In the first experiment, juvenile bream were exposed to predatory mangrove jack (Lutjanus argentimaculatus) fed exclusively on bream flesh while housed in tanks with and without refuge. Predator training altered fish behaviour when fish were re-exposed to predators, but the effects were subtle and varied between groups of fish. In contrast, refuge created strong and consistent changes in behaviour, significantly slowing down the amount of time that fish took to consume food. A second experiment focused on the effects of refuge. Bream were trained to use artificial seagrass or house bricks as refuge and then exposed to mangrove jacks in a laboratory predation experiment. When refuge was available, fish significantly slowed down their feeding rate. There was a small, transient increase in survival for fish given seagrass refuges, but this was irrespective of whether the bream were trained to use refuge. The results of this study indicate that the use of refuge may be innate and the benefits of refuge may be available to naive hatchery-reared fish or fish trained to use refuge shortly before release. This suggests that there is potential to improve post-release survival of fingerlings without time-consuming and expensive hatchery training.