Bioconcentration of chlorinated anilines and benzene in fish: Preliminary results

• 1.1. Seven chlorinated anilines and one chlorinated benzene were tested for their ability to bioconcentrate in guppies (Poecilia reticulata) under different experimental conditions.
• 2.2. Interactions between compounds in a mixture influence the bioconcentration of some chlorinated anilines. These interactions result in either an increase or a decrease of bioconcentration, depending on the compound studied.
• 3.3. Exposure concentration can have an effect on the extent of bioconcentration of some chlorinated anilines.

     

Partial characterization and subunit analysis of major phosphoproteins of egg yolk in the fish,Oryzias latipes

• 1.1. Molecular weight estimation and subunit analysis of four yolk phosphoproteins (PP1-PP4) in medaka (Oryzias latipes) eggs were performed.
• 2.2. PP1 (M_r ≈ 210,000) and PP2 (M_r ≈ 180,000) were found to be heterodimers composed of subunits of 113,000 and 94,000 and subunits of 84,000 and 72,000, respectively.
• 3.3. PP3 and PP4 [phosvitins of medaka (Murakami et al., 1990, Devl. Growth Differ.32, 619–627)], were monomeric phosphoproteins having mol. wts of about 40,000 and about 20,000, respectively.
• 4.4. Lipid composition of the mixture of PP1 and PP2, vitellogenin and yolk were found to be almost the same. PP1 and PP2 are probably lipovitellins of medaka.

     

The usefulness of histopathology in aquatic toxicity studies.

1. A survey was carried out to examine the usefulness of histopathology for the identification of toxic effects of environmental contaminants in fish. 2. Two small fish species, Poecilia reticulata (guppy) and Oryzias latipes (medaka) were used, and two exposure periods (1 and 3 months) were chosen. 3. The following compounds were studied: beta-hexachlorocyclohexane, bis(tri-n-tributyltin)oxide, di-n-butyltindichloride, sodium bromide, methyl bromide, and methylmercury chloride. 4. The following is concluded: histopathology provides useful data in characterizing toxic effects in fish; there is a slight advantage for Poecilia reticulata over Oryzias latipes; there is no advantage for 3 months exposure vs 1 month.     

The effect of a toxic dinoflagellate (Alexandrium tamarense) on the oxygen uptake of juvenile filter-feeding bivalve molluscs

• 1.1. Oxygen uptake and grazing rates of juvenile bivalve molluscs Mytilus edulis, Mya arenaria, Geukensia demissa, Placopecten magellanicus and Crassostrea virginica were measured following 1 hr exposure to bloom concentrations (10⁶ cells/1) of the toxic dinoflagellate Alexandrium tamarense (GT429) using a non-toxic clone of the same species (PLY 173) as control.
• 2.2. For all bivalves, prefeeding estimates of V̇O₂ were similar to postfeeding values and values recorded 24 hr after exposure to bloom conditions.
• 3.3. V̇O₂ was similar for bivalves fed on both the toxic and non-toxic strains of A. tamarense suggesting that there were no adverse effects on V̇O₂ following 1 hr exposure to toxic GT429.
• 4.4. Bivalves differed in their rates of grazing between toxic GT429 and non-toxic PLY 173. Similar grazing rates were recorded for M. edulis and G. demissa. For P. magellanicus and M. arenaria reduced rates of clearance were recorded in GT429 compared with the non-toxic strain.

     

Morphometry and composition of red drum otoliths: Changes associated with temperature,somatic growth rate,and age

• 1.1. Size and composition of sagittal otoliths from red drum, Sciaenops ocellatus (Sciaenidae), reared at various constant temperatures were compared with otoliths from wild-caught fish.
• 2.2. Uncoupling of otolith growth and somatic growth in laboratory-reared fish was evident in otolith length, area, volume, weight, density, and organic fraction.
• 3.3. Fish grown at low temperatures had significantly smaller and less dense otoliths having a greater organic content than fish of the same size grown at higher temperatures.
• 4.4. Changes in inorganic elements were poorly related to temperature in laboratory-reared fish.
• 5.5. The effect of temperature on otolith elemental composition was small relative to the effects of age and its associated physiological changes.

     

Laboratory studies on the oxygen consumption of the marine teleost,Lichia amia (Linnaeus, 1758)

• 1.1. The oxygen consumption of the marine teleost, Lichia amia was investigated under controlled laboratory conditions.
• 2.2. The routine oxygen consumption showed a strong circadian rhythm with the fish being mainly active during the light period.
• 3.3. The specific mass exponent (dimension: μg O₂/g/hr) is temperature independent and ranges from 0.27–0.29.
• 4.4. Starving the fish results in a mean decrease in active, routine and standard oxygen consumption of 21%, 24% and 20%, respectively.
• 5.5. Feecling led to an increase in the oxygen consumption of the teleosts, with the mean metabolic rate over the 24 hr that followed, being 58% and 50% higher for fish that had been starved for 162hr and 40 hr, respectively.
• 6.6. Apparent SDA showed some variation and ranged from 6.0 to 35.5%.
• 7.7. The results obtained are generally in agreement with those recorded for other teleosts.

     

Main kinetic characteristics of acetylcholinesterase from brain of Hypostomus punctatus,a Brazilian bentonic fish (cascudo)

• 1.1. A potentiometric method for the assay of cholinesterase has been proposed and compared with a colorimetric assay.
• 2.2. Main kinetic parameters of cholinesterase from Hypostomus punctatus brain were determined indicating that true acetylcholinesterase is by far the predominant enzyme in the brain of this fish.
• 3.3. We have compared our data with published results described from other fish species.
• 4.4. The enzyme inhibition achieved after 3 hr incubation of brain homogenates with ethyl-parathion have indicated that this enzyme shows a characteristic organophosphorous sensitive behavior.

     

Comparative study of proteolytic enzymes in the digestive tracts of the european sea bass and hybrid striped bass reared in freshwater

• 1.1. A comparative study of the proteolytic activity in four different sections of the digestive tracts of the European sea bass (Dicentrarchus labrax) and hybrid striped bass (Morone chrysops × M. saxatilis) reared in freshwater revealed minor differences between these fish.
• 2.2. Tryptic activity plays a major role in the proteolytic process in both fish.
• 3.3. The activity of seven intestinal proteolytic enzymes was detected utilizing a combination of specific substrates and inhibitors.
• 4.4. High levels of proteolytic activity were detected in both the proximal and distal sections of the fish intestine at a high pH range (9–10).
• 5.5. In situ monitoring of pH levels revealed a lower pH level in the intestinal proximal section of hybrid striped bass compared with the distal section.
• 6.6. In contrast, higher pH levels were detected at the proximal compared with the distal sections of D. labrax intestine.

     

Lysosomal perturbations in fish liver as indicators for toxic effects of environmental pollution

• 1.1. Lysomones play a key role in liver injury in fish caused by organic and inorganic xenobiotics. The lysosomal stability test was transferred to fish liver with the aim of testing responsive and practicable methods for biological-effects monitoring.
• 2.2. A two-step response of lysosomes in fish liver could be discerned, reflected by the activity (number and size of lysosomes) and the injury (membrane destabilisation) of the lysosomal detoxifying system.
• 3.3. Significant differences, with respect to lysosomal enlargement, membrane stability and pathological lipid accumulation, were found along a pollution gradient throughout the year.
• 4.4. The lysosomal tests clearly reflect the breakdown of the adaptive capacity of the fish liver to toxic injury. Therefore, a test battery measuring lysosomal perturbations should be recommended for the biological-effects monitoring.

     

A histopathological analysis of wild and transplanted Dreissena polymorpha from the dutch sector of the river maas

• 1.1. The histopathology of zebra mussel populations (Dreissena polymorpha) which were transplanted and exposed in baskets in the Dutch sector of the River Maas (5 locations) were compared with indigenous wild mussels at the same locations and at a clean reference site in the Ijsselmeer.
• 2.2. All groups were sectioned histologically and examined to quantify cytological damage and pathology of a wide range of tissues, as well as to examine parasitology and to assess their reproductive state.
• 3.3. Results show a significant reduction in general cytological quality and an increase in observed pathological conditions in the wild populations at the 3 downstream stations.
• 4.4. The transplanted (active biomonitoring) groups of mussels clearly showed a similar trend in condition after only 42 days exposure at these sites.
• 5.5. The influence of an industrial spillage of Cd in the Maas during the exposures is examined against this background of locally varying “health”.

     

Strontium-calcium concentration ratios in fish otoliths as environmental indicators

• 1.1. External and internal examinations of otoliths in fishes for macrostructure and microstructure has demonstated yearly, daily and population rhythmic patterns.
• 2.2. Chemical analyses (atomic absorption) of otolith carbonate from reared Fundulus heteroclitus for strontium-calcium concentration ratios demonstrated changes in chemistry related to temperature.
• 3.3. Microprobe analyses made it feasible to interpret almost daily changes in temperature to provide the temperature history of an individual fish.
• 4.4. A combination of microprobe analyses and daily increment analyses of otoliths can provide a life history profile for individual fish and can provide information on the environmental history of each fish.
• 5.5. Such information is vital to our understanding of the processes underlying recruitment and growth rates, and would make it possible to link growth and mortality rates to environmental occurrences.

     

Solving parasite-related problems in cultured marine fish

• 1.1. Our knowledge of parasite born e diseases of cultured marine fish is restricted by the limited extent of practiced mariculture.
• 2.2. Several parasites, pathogenic to fish including capsaloid, microcotylid and diclidophoran monogeneans and caligid copepods are ubiquitous in mariculture systems in diverse species of fish and geographical regions.
• 3.3. The alga Amyloodinium ocellatum and the ciliated protozoan Cryptocaryon irritons are not as ubiquitous, but nevertheless present the most serious risk to farmed fish of most species due to their high pathogenicity, fecundity and resistance to conventional means of control.
• 4.4. Infections in maricultured fish are dominated by monoxenous parasites. Occurence of heteroxenous parasites is restricted by their requirement for additional hosts to maintain transmission.
• 5.5. Cage culture allows free exchange of infection between caged and native fishes; in inshore systems infections have to be introduced primarily from external sources.
• 6.6. Water supply does not appear to be an efficient route of entry of infection into culture systems; parasites are introduced either by wild fry or wild breeders collected into the system, or with wild fish infiltrating via water supply or drainage.
• 7.7. Adverse growth conditions are the most common circumstances in outbreak of epizooites. Over-crowding does not appear to promote primarily epizooites, its impact is indirect by contributing to the deterioration of the growth conditions.
• 8.8. Epizooites are likely to occur also in juvenile, immunologically naive fish as well as following introduction of parasites into unexperienced fish population.
• 9.9. Control has been implemented thus far through an empirical approach. Recent research is geared towards the development of methodology specifically designed to the needs of mariculture.

     

Effects of Size and Geographical Origin on Atlantic salmon,Salmo salar,Mucin O-Glycan Repertoire

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Highlights

• •Atlantic salmon O-glycome expanded to 169 structures in three epithelia.
• •Low interindividual variation amongst all populations and geographical regions.
• •Small variations in glycosylation between geographical locations and fish size.
• •Prominent fucosylation in gastrointestinal mucins from Tasmanian fish.

     

Phosphoglucomutase,superoxide dismutase and glucose 6-phosphate dehydrogenase in fish collected from Iraq and Kuwait—A comparative study

• 1.1. Tissue extracts of heart, kidney, gills and eye lens were electrophoretically examined for phosphoglucose mutase (PGM), superoxide dismutase (SOD), and glucose 6-phosphate dehydrogenase (G6PDH) activity in 32 species of teleostean fish.
• 2.2. One locus of PGM, SOD and G6PDH was found in all groups of fish studied.
• 3.3. The electrophoretic patterns of PGM and SOD can be considered as a good taxonomic criterion to differentiate Acanthopagrus latus, Lethrinus kallopterus, Otolithus ruber, Plectorhynchus schotaf and Synaptura orientalis from the remaining fish species studied.
• 4.4. G6PDH and hexose 6-phosphate dehydrogenase (H6PDH) can be considered to be of a less taxonomic importance in differentiating the species of fish under consideration.

     

Sodium balance in adult atlantic salmon (Salmo salar L.) during migration into neutral and acid fresh water

• 1.1. In sea-water, adult salmon (S. salar) exchange an average of 12.6% of total body sodium/hr.
• 2.2. Following transfer to fresh water sodium uptake follows Michaelis-Menton kinetics. F_max = 2.40 mmol Na/1 ECF/hr, K_m = 0.26 mmol Na/1. The uptake system is fully activated immediately following transfer to fresh water.
• 3.3. Post smolts adapted to sea-water for 3 months take up sodium at only one third of the rate of adult fish following return to fresh water.
• 4.4. The concentration of prolactin in the plasma is low in sea-water adapted fish and does not rise during the first 8 hr in fresh water.
• 5.5. At pH 5 sodium uptake is reduced by almost 90%, even in the absence of aluminium, but recovers immediately on return to neutral water.
• 6.6. At pH 5 and 20 μmol Al/1 there is little further effect on sodium uptake but after 6 hr in aluminium the inhibition of sodium uptake continues after return to neutral aluminium fresh water and uptake is only 50% of normal 24 hr later.

     

Correlation between body color and behavior in the upside-down catfish,Synodontis nigriventris

• 1.1. Unlike common fishes and as its Latin name implies, the upside-down catfish, Synodontis nigriventris, possesses dark ventral skin. Microscopic observation reveals that melanophores are present on both the ventral and the dorsal skin but differ in size and density of distribution.
• 2.2. The darkness of both sides of the fish changes in accordance with that of the background.
• 3.3. At night, the fish are very active and the body becomes pale. The change in color is more noticeable in the dorsal than the ventral skin.
• 4.4. When melatonin was added to the bathing water, the fish became pale and swam restlessly even when they were exposed to the black background.
• 5.5. It was found that the catfish preferred the black background to the white one.

     

Regional variation in cuticular hydrocarbon composition in the common house cricket,Acheta domesticus

• 1.1. The hydrocarbon composition of different cuticular regions (pronotum, legs, abdominal tergites and sternites, pleural membrane) was determined for adult female crickets (Acheta domesticus).
• 2.2. Hydrocarbon groups included n-alkanes, 2-methylalkanes, long-chain internally branched monomethyl- and dimethyalkanes, n-alkenes, 2-methylalkenes and alkadienes.
• 3.3. Saturated hydrocarbons were more abundant than unsaturated hydrocarbons and branched saturates more abundant than n-alkanes in all regions of the cuticle examined.
• 4.4. Except for a higher percentage of n-alkanes in the pleural membrane (soft cuticle), little difference was noted in compositional patterns or relative amounts of individual molecules from the different cuticular regions.

     

Scale regeneration of tilapia (Oreochromis niloticus) under various ambient and dietary calcium concentrations

• 1.1. Scale regeneration was examined in Oreochromis niloticus under normal, dietary calcium-deficient, and both dietary and ambient water calcium-deficient conditions.
• 2.2. Calcium contents of regenerating scales were dependent on the calcium status of the fish, but areal growth of the scales was independent.
• 3.3. Transient hypocalcemia accompanied with a loss of calcium from original scales was observed in descaled fish in dietary calcium deficiency, and intact and descaled fish in both dietary and ambient water calcium deficiency.
• 4.4. The results suggested that calcium mobilized from internal sources was insufficient and both water and dietary calcium were necessary for normal calcification of the regenerating scales.

     

Chemical feeding stimulants for the herbivorous fish,Tilapia zillii

• 1.1. Chemical feeding stimulants for an herbivorous fish, Tilapia zillii have been determined by fractionation and bioassay of substances derived from a model food plant.
• 2.2. Stimulation was produced by amino acids; glutamic acid, aspartic acid, serine, lysine and alanine produced the bulk of stimulatory activity.
• 3.3. These amino acids are among the most abundant in the test plant, and are markedly different from the amino acids found to stimulate feeding in carnivorous fish.
• 4.4. On the basis of these results, a chemically-mediated mechanism of feeding niche separation is postulated.

     

Heart rate and its cholinergic control in the sole (Solea vulgaris), acclimatized to different temperatures

• 1.1. The effects of thermal acclimatization at 10 and 24°C on heart rate were investigated on unrestrained soles (Solea vulgaris).
• 2.2. The sensitivity of heart rate to temperature changes induced by temperature acclimatization was higher in cold-acclimatized than in warm-acclimatized soles.
• 3.3. Heart rate of cold-acclimatized fish to temperature changes was not affected by blocking the vagal tone with atropine.
• 4.4. After atropine treatment the ability of heart rate to show thermal compensation decreased in warm-acclimatized soles.
• 5.5. It is suggested that the vagus nerve can function differently at different temperatures.