Mobilization of copper among tissues in the estuarine crab Scylla serrata (Forskal) under imposed starvation

The quantitative changes in copper free and bound to proteins in haemolymph and different forms of copper in muscle and hepatopancreas under imposed starvation were studied in the estuarine mud crab Scylla serrata. During the course of starvation, both haemolymph copper free and bound to proteins significantly declined and the regression analyses of these data further revealed that the haemolymph copper-free proteins were more affected than copper-bound proteins. The multiple stress condition namely injury and exsanguination along with starvation resulted in an earlier release and/or degradation of both these proteins. Hepatopancreas periodically accumulates and releases copper during starvation. The copper levels in haemolymph and hepatopancreas during different days of starvation showed a close inverse relationship between these two tissues. These changes in hepatopancreas were predominantly reflected in the copper that exists in association with low molecular weight substances. It is found that the copper thus accumulated was partly released back into haemolymph and a fraction may be excreted. This study also indicates the major role played by the low molecular weight substances in accommodation, detoxification and mobilization of copper in the decapod hepatopancreas during imposed starvation.     

The importance of juveniles in structuring a littoral macrobenthic community

The relationships between individual dry weight and bodycontent of the essential metals copper and zinc and of therespiratory pigment haemocyanin have been investigated in fourBritish species of caridean decapod crustaceans, Palaemonelegans, Palaemon longirostris, Palaemonetesvarians and Crangon crangon. Also considered were thebody concentrations of soluble copper and copper associatedwith haemocyanin. These decapods regulate total bodyconcentrations of copper and zinc to approximately constantlevels which can vary interspecifically. An attempt is made tointerpret these regulated concentrations in terms of essentialrequirements for the metals in the physiological functioningof haemocyanin, the body concentration of which variesinterspecifically and intraspecifically with environmentalvariables.     

Étude préliminaire des variations circadiennes des protéines de l'hémolymphe de Penaeus japonicus Bate

The protein contents of the haemolymph in the decapod crustacean Penaeus japonicus Bate exhibit a tricircadian rhythm characterized by two maxima during the night and another one during the day. During the night the total protein concentration in haemolymph is higher in males. Maximal values in males are approximately four times greater (100 mg/ml) than minimal ones (25 mg/ml). Variations are less in females: maximal values are approximately two and a half times higher (75 mg/ml) than minimal ones (30 mg/ml).Electrophoresis in polyacrylamide gradient showed that the different protein constituents in general exhibit similar circadian variations. Time of acrophases depends on the sex and the stage in the intermoult cycle. On the other hand, the mean concentration of each protein constituent calculated from values measured at different times of the day are similar whatever the sex and moulting stage. Between 0 and 6 h certain protein fractions - two in females and one in males - are no longer detectable by electrophoresis. At 12 h, concentration of haemocyanin and its subunits increase simultaneously in both sexes.     

Accumulation of manganese in the haemolymph, nerve and muscle tissue of Nephrops norvegicus (L.) and its effect on neuromuscular performance

Exposure of Norway lobsters, Nephrops norvegicus (L.) for 3 weeks to manganese concentrations, (5 & 10 mg Mn l(-1) (90-180 microM)), led to its accumulation in various body tissues. The highest concentration was in nerve tissue (brain and abdominal ganglia) which had up to 6 times (on wet wt. basis) the manganese concentration of the exposure concentration, whereas the haemolymph accumulated 3 times and the muscle tissue only 0.5 times the exposure concentration. In the haemolymph the manganese was bound mainly to protein, predominantly (80-90%) to the respiratory protein haemocyanin, as the concentration was 14 times higher in the protein fraction than in the supernatant. Manganese did not substitute for copper in the haemocyanin, as the copper concentration remained constant despite the manganese exposure. The possibility that manganese exposure induced neurotoxic effects sufficient to reduce neuromuscular performance was assessed from the kinematics of free tail-flip swimming, and from measures of the forces produced by abdominal movements in tethered animals. No significant reduction in tail flip velocity or flexion force, but a significant reduction in the maximum post-flip extension force was found. No correlation was found between the manganese concentration in a single tissue or different fractions of the haemolymph and the post-flip extension, except for a weak negative correlation with the manganese concentration in the abdominal ganglion. The ecophysiological implications of these results are discussed.     

Free amino acids in claw muscle and haemolymph from Australian freshwater crayfish at different stages of the moult cycle

Amino acids were measured in claw muscle and haemolymph in the freshwater decapod crustacean, Cherax destructor, at different stages of the moult cycle. The total pool of amino acids in muscles from animals in intermoult (97+/-13 mmol kg(-1) muscle), premoult (80+/-20 mmol kg(-1)) and postmoult (97+/-19 mmol kg(-1)) were not significantly different. Despite the relatively stable total pool of amino acids, there were changes in the concentrations of alanine, glutamine and proline over the moult cycle. Compared to intermoult, claw muscles from animals in premoult had a lower concentration of proline, and animals in postmoult had higher concentrations of alanine and glutamine, but lower concentrations of proline. Concentrations of alanine and glutamine in claw muscle of animals in postmoult were higher and proline concentrations lower than in the same animals during the premoult stage. The concentration of proline in haemolymph was lower in animals in premoult and postmoult compared to intermoult. The total amino acid pool in the claw muscle of Cherax destructor did not change significantly over the moult which is distinctly different to the changes in amino acids reported in the claw muscles of marine decapod crustaceans.     

Circadian variations in hemolymph lipids and lipoproteins and in hepatopancreatic lipids of the shrimp Penaeus japonicus

Lipids content of the haemolymph and the hepatopancreas in the decapod Crustacean P. japonicus exhibits a bicircadian rhythm characterized by one maximum in the night and another one during the day. The maximal values in the haemolymph are approximately two and a half times greater (8 mg/ml) than minimal ones (3 mg/ml). Variations are less important in the hepatopancreas. A bicircadian rhythm of lipid classes in the haemolymph is observed very significantly in concentration of polar lipids and free sterols with maximal values (6.87 mg/ml and 0.59 mg/ml) and minimal values (2.63 mg/ml and 0.23 mg/ml) respectively. Polar lipids are the major lipid fractions in the haemolymph (87%). The electrophoretic behaviour of haemolymph lipoproteins is determined.     

Phosphorus fractions of crayfish haemolymph, serum and haemocyanin

Different amounts of haemolymph proteins participate in clot formation in Astacus leptodactylus and Orconectes limosus (20% and 10%, respectively), although in both species the content of proteins in haemolymph is similar. In both species the content of total phosphorus in the clot was similar (0.33-0.49%, w/w) but it was about 6 times lower in serum of O. limosus than in serum of A. leptodactylus (2.2 and 14.8 mg/100 ml, respectively). An even greater difference in phosphorus content was found in the protein precipitated from serum. In both species lipid phosphorus was predominant (77% of total haemolymph phosphorus in A. leptodactylus and 52% in O. limosus). Phospholipids were found mainly in serum. Only traces of phosphorus (0.005%) and small amounts of fatty acids were found in purified haemocyanin preparations.     

The combined effect of temperature and salinity changes on osmoregulation and haemocyanin concentration in Saduria entomon (Linnaeus, 1758)

Global warming is having an impact on the temperature and salinity of Baltic Sea waters. Therefore, it is important to determine the conditions in which animals can exist and how these changes may influence their functioning. Hence, the purpose of this research was to determine the broad tolerance limits of temperature and salinity of the glacial relict Saduria entomon by studying its behaviour, osmoregulatory ability and haemocyanin concentration. This effect of temperature was confirmed in the laboratory for individuals acclimated to different salinity and temperature regimes. Changes in the physiological parameters of S. entomon at various temperatures (5.5–21.5°C) and salinity levels (1–15 PSU) were recorded. There were statistically significant differences in haemolymph osmotic pressure under the influence of salinity and temperature. The mean haemolymph osmotic pressures were the lowest at 1 PSU at all the temperatures examined and the highest at 15 PSU and high temperatures 16.5 and 21.5°C. The haemocyanin concentration decreased significantly with increasing temperature at 1 PSU. There was a significant difference in haemocyanin concentration due to salinity at temperatures of 5.5 and 10.0°C (the haemocyanin concentration decreased with increasing salinity). The results showed that, although S. entomon is classified as a cold-water animal, it can survive at high temperatures above 16.5°C at least for a short time, as it is capable of osmoregulation. The tolerance to temperature changes was better than expected.     

Oxygen uptake, diffusion limitation, and diffusing capacity of the bipectinate gills of the abalone, Haliotis iris (Mollusca: Prosobranchia)

Extant abalone retain an ancestral system of gas exchange consisting of paired bipectinate gills. This paper examines the hypothesis that fundamental inefficiencies of this arrangement led to the extensive radiation observed in prosobranch gas exchange organs. Oxygen uptake at 15 degrees C was examined in the right gill of resting adult blackfoot abalone, Haliotis iris Martyn 1784. Pre- and post-branchial haemolymph and water were sampled and oxygen content, partial pressure (Po2), pH, and haemocyanin content measured; in vivo haemolymph flow rate was determined by an acoustic pulsed-Doppler flowmeter. During a single pass across the gills, mean seawater Po2 fell from 138.7 Torr to 83.4 Torr, while haemolymph Po2 rose from 37.2 Torr to 77.0 Torr raising total O2 content from 0.226 to 0.346 mmol L(-1). Haemolymph flowed through the right gill at a mean rate of 9.6 mL min(-1) and carried 0.151 to 0.355 mmol L(-1) of haemocyanin (mean body mass 421 g). Only 34.7% of the oxygen carried in the arterial haemolymph was taken up by the tissues and less than half of this was contributed by haemocyanin. A diffusion limitation index (Ldiff) of 0.47-0.52, a well-matched ventilation-perfusion ratio (1.2-1.4) and a diffusing capacity (D) of 0.174 micromol O2 kg(-1) Torr(-1) indicate that the gills operate efficiently and are able to meet the oxygen requirements of the resting abalone.     

A brief re-examination of the function and regulation of extracellular magnesium and its relationship to activity in crustacean arthropods

• 1.1. The magnesium ion [Mg²⁺] plays an important role as a co-factor in enzyme systems and as a modulator of the haemocyanin of crustacean arthropods.
• 2.2. Mg²⁺ is actively regulated in most decapod crustaceans via the antennal gland. The degree of regulation can be correlated to some extent with the “activity” of a particular species although there are “exceptions to the rule”.
• 3.3. Intraspecific studies indicate that there is a clear relationship between haemolymph [Mg²⁺] and the level of activity in particular crustacean species.
• 4.4. A plea is made for the investigation of temporal changes in the [Mg²⁺] of the haemolymph of a number of crustaceans and for more studies of Mg²⁺ homoeostasis in general.

     

The influence of starvation and copper exposure on the composition of the dorsal carapace and distribution of trace metals in the shore crab Carcinus maenas (L.)

1. The influence of starvation and copper exposure on the composition of the carapace of the shore crab, Carcinus maenas has been investigated. The effects of the concentrations of selected trace metals in the carapace and midgut gland have also been examined.2. Differences in nutritional state did not affect the concentrations or relative proportions of the principle carapace components (calcium, chitin and protein), but starvation was associated with a reduction in carapace copper concentration. Copper concentration in the midgut gland increased in “starved” crabs, while midgut gland zinc and calcium concentrations remained unchanged.3. Starvation in combination with copper exposure (0.5 mg Cu/1) resulted in alterations in both carapace composition and trace metal loads. Carapace calcium concentrations were reduced significantly following copper exposure irrespective of the nutritional state of the crabs. However, the reduction was more marked in “fed” crabs than in “starved” animals.4. Copper-exposed crabs exhibited raised carapace copper concentrations while carapace zinc concentrations were depressed. Such changes were most pronounced in copper-exposed “starved” crabs.5. Calcium concentrations in the midgut glands of “starved” copper-exposed animals were significantly elevated compared with those in either control or “fed”, copper-exposed crabs.6. The findings are discussed with regard to their ecotoxicological significance.     

Carbohydrate and fatty acid titres during flight of the migrant noctuid moth,Anticarsia gemmatalis Hübner

Haemolymph concentrations of total carbohydrate and fatty acids were determined in velvetbean caterpillar (Anticarsia gemmatalis Hübner, Lepidoptera: Noctuidae) adult females throughout a 4-hr period of tethered flight. Total carbohydrate concentration decreased from approx. 30 to 10 μg/μl during the first 45 min of flight. Total fatty acid concentration increased from approx. 20 to 40 μg/μl during the first 60 min of flight and then declined to and stabilized at preflight levels. The decrease in wet weight (from approx. 97 to 80 mg/moth) during flight was probably due to defecation since no change in dry weight or haemolymph volume occurred. After 4 hr of flight, no apparent change in whole body lipid content (approx. 12 mg/moth) was observed but the much smaller carbohydrate content was reduced approx. 80% (from approx. 0.6 to 0.1 mg/moth). Approximately equal amounts (approx. 360–550 μg) of carbohydrate and lipid were removed from the haemolymph during 4 hr of flight. Changes in the haemolymph concentrations of palmitic, oleic and linoleic acids correspond to the changes in total fatty acid concentration of the haemolymph, indicating that these are the major components of the lipid mobilized and utilized during flight of A. gemmatalis.     

Quantitative variations during the intermoult cycle of peptides related to human growth hormone in Palaemon serratus (Crustacea; Decapoda)

Growth hormone-like peptides cross-reacting with an antiserum human specific were detected in the haemolymph, the midgut gland and stomach extracts of the prawn Palaemon serratus using radioimmunoassay. Parallelism was observed between the dilution sample curves and the hGH standard curve. Moreover, at least one peptide exhibiting a similar apparent molecular weight (22,000 daltons) with hGH was detected. In the three samples different amounts were detected during intermolt cycle: between 1.3 and 2.2 ng/ml in the haemolymph, 23 and 84 ng/g wet weight for the midgut gland, 12 and 71 ng/g ww for the stomach. The stages with highest values were respectively: D 1" and D 1"', D 1"' and D 2, D 3 and AB.     

Storage-excretion of metallic cations in the adult housefly, Musca domestica

The objective of this investigation was to elucidate further the phenomenon of storage-excretion of metallic cations in the housefly. The sites for deposition of zinc, calcium and copper have been identified in this study. The metal intake of the flies was altered by raising one group on sucrose and tap water while in the experimental groups sucrose was supplemented with either 0.05% zinc sulphate, 0.05% calcium phosphate or 0.03% copper sulphate. There were no significant differences in the average life spans of the flies in different groups indicating physiological tolerance to the higher mineral intake. The Malpighian tubules, the midgut and the remainder of the body were analyzed for mineral content in houseflies ranging from 1 to 25 days posteclosion by atomic absorption spectrophotometry. There was a progressive age-associated increase in the total metal content of the flies with age. Zinc and calcium were primarily stored in the Malpighian tubules whereas copper was sequestered in the midgut. Microscopic examination of the epithelial cells of the Malpighian tubules and the midgut revealed a corresponding age-associated increase in mineralized concretions.     

Effects of starvation on haemolymphatic glucose levels, glycogen contents and nucleotidase activities in different tissues of Helix aspersa (Müller, 1774) (Mollusca, Gastropoda)

In the present study, the glucose concentration in the haemolymph and glycogen levels were determined in the various body parts of the Helix aspersa snail after feeding lettuce ad libitum and after various periods of starvation. To characterize the effect of starvation on nucleotidase activity, enzyme assays were performed on membranes of the nervous ganglia and digestive gland. Results demonstrated the maintenance of the haemolymph glucose concentration for up to 30 days of starvation, probably due to the consumption of glycogen from the mantle. In the nervous ganglia, depletion of glycogen occurs progressively during the different periods of starvation. No significant changes were observed on ATP and ADP hydrolysis in the membranes of nervous ganglia and no alterations in Ca2+ -ATPase and Mg2+ -ATPase occurred in the membranes of the digestive gland of H. aspersa during the different periods of starvation. Although there were no changes in the enzyme activities during starvation, they could be modulated by effectors in situ with concomitant changes in products/reactants during starvation.     

A functional analysis of the shift from gill- to lung-breathing during the evolution of land crabs (Crustacea, Decapoda)

The evolution of air-breathing in land crabs is associated with a progressive shift in the primary site of respiratory gas exchange from the diffusion-limited gills used for water-breathing, via a simple 'cutaneous' lung surface to the perfusion-limited, invaginated lung described in the mountain crab, Pseudothelphusa garmani. The reduced diffusion limitation over the lungs facilitates oxygen transfer from air to the tissues at lower ventilation rates but is associated with accumulation of carbon dioxide. A potential respiratory acidosis is buffered by the respiratory pigment haemocyanin and by elevation of haemolymph bicarbonate levels. These changes parallel those described in vertebrates but air-breathing crustaceans maintain relatively low carbon dioxide levels in the haemolymph, either by retaining an aquatic route for its elimination over the reduced gills or by blowing it off across the lung. Maintenance of low carbon dioxide levels may be associated with a limited capacity to buffer against an acidosis due to low levels of circulating haemocyanin (i.e. crustaceans lack red blood cells). This may ultimately limit their survival in air as an acidosis will reduce oxygen transport due to a marked Bohr effect on haemocyanin. The primary role of an invaginated lung may be to reduce rates of water loss in air.     

Tissue glycolytic potentials of penaeid prawn, Metapenaeus monoceros during methylparathion, carbaryl and aldrin exposure.

Changes in midgut gland and muscle tissue glycolytic potentials of penaeid prawn, Metapenaeus monoceros following exposure to methylparathion, carbaryl and aldrin were studied. A decrease in total carbohydrates, glycogen and pyruvate and an increase in lactate levels were observed. An increase in phosphorylase 'a' and aldolase activity levels suggested increased formation of trioses during selected insecticide toxicity. The decrease in the lactate dehydrogenase activity levels and an increase in the lactate content indicative of reduced mobilization of pyruvate into the citric acid cycle. During selected insecticide exposure, the prawn tissues adopting some sort of regulatory pathways such as enhanced glycolysis and a shift of metabolic emphasis from aerobiosis to anaerobiosis. All the above mentioned changes were more pronounced in the midgut gland compared to muscle tissue. The per cent decrease or increase are more under aldrin exposure followed by carbaryl and methylparathion exposure. The selected insecticides in the present investigation, though belongs to different representative groups, but appears to be neurotoxic leading to disturbances in the carbohydrate catabolism.     

Glutathione content and GSH S-transferase activity in midgut gland of Procambarus clarkii. Sex differences, the effect of fasting, and their implications in cadmium toxicity

1. Glutathione content and GSH S-transferase activity in the midgut gland of Procambarus clarkii (P. c.) of different sex and body weight are presented. 2. Procambarus clarkii females' GSH concentration in the midgut gland decreases to a higher extent upon fasting, compared with males. 3. Procambarus clarkii females, both in control and fasting conditions, have a slightly higher GSH S-transferase activity than males. 4. Cadmium present in water only affects GSH content and GSH S-transferase activity (after 96 hr) in midgut gland, with cadmium chloride concentrations higher than 100 micrograms/l.     

Lactic acid formation in crustaceans and the liver function of the midgut gland questioned.

1. The possibility of the midgut gland of the crustacean (Cherax destructor) functioning as a liver has been investigated. 2. Seven species of crustaceans accumulate lactic acid in the haemolymph when exercised. The rate of disappearance of lactate in Homarus gammarus and in C. destructor is very slow when compared with man. 3. In the midgut gland of C. destructor no firm evidence was obtained for gluconeogenesis from lactate and for ketogenesis from fatty acids. 4. It is concluded that there is at present no justification for the common practice of calling the midgut gland an hepatopancreas.