Cadmium accumulation and metallothionein-like proteins in the sea starAsterias rubens

Sea stars were exposed for four months to cadmium at 50 g Cd/L. The cadmium content of stomachs, pyloric caeca, gonads and body wall was determined after 2, 4, 6, 8, and 16 weeks of exposure. The highest accumulation rates were found for body wall and pyloric caeca. The lowest accumulation rate was found for the gonads. In all tissues cadmium accumulation showed saturation kinetics. The body wall contained the largest part of the accumulated cadmium.Sephadex G-75 gel filtration experiments demonstrated the presence of metal-binding, metallothionein (MT)-like proteins with a molecular weight of 10.8 kD in cytosolic fractions of pyloric caeca from unexposed sea stars. The MT-like proteins contained mainly zinc and a small amount of copper. During exposure, the MT-like proteins accumulated cadmium at a relatively high rate, but a steady state was reached after 8 weeks, indicating thatin vivo, the Cd-binding capacity of these proteins was limited. When pyloric caeca cytosol from unexposed sea stars was incubated with cadmiumin vitro, the MT-like proteins could bind larger amounts of cadmium thanin vivo during the Cd exposure. After 16 weeks of Cd exposure, thein vitro Cd-binding capacity had hardly increased.Low-molecular-weight metal-binding proteins were absent in cytosolic fractions of the testes, ovaries and oocytes from Cd-exposed sea stars, even after four months of exposure. The cadmium accumulated in the gonads was bound exclusively to high-molecular-weight proteins, which accumulated cadmium at a relatively low rate, compared to the MT-like proteins in the pyloric caeca. The absence of MT-like proteins in the gonads may explain the low cadmium accumulation rates found for these organs, but as a consequence, the accumulated cadmium is not detoxified.     

Effects of cadmium and PCBs on reproduction of the sea star Asterias rubens: aberrations in the early development

In semifield experiments sea stars, Asterias rubens, were exposed to 25 micrograms Cd/liter or fed with mussels containing 0.6 microgram/g wet wt PCBs (Clophen A50). After 5 months of exposure, Cd concentrations in testes and ovaries were respectively 17 and 50 times higher than those in unexposed sea stars. PCB concentrations were respectively 7 and 9 times higher. With spermatozoa obtained from Cd- or PCB-exposed sea stars, normal fertilization could be achieved. However, maturation of oocytes from Cd-exposed animals was delayed and early development of embryos from Cd- or PCB-exposed animals was disturbed. Due to aberrations during the early development only 24 and 30% of the embryos obtained from Cd- or PCB-exposed sea stars, respectively, had developed to normal bipinnaria larvae after 1 week.     

Assessment of industrial sewage impacts by adenylate energy charge measurements in the bivalve Cerastoderma edule

Laboratory toxicity tests performed on the bivalve Cerastoderma edule submitted to sublethal concentrations of paper mill effluent revealed significant decreases of adenylate energy charge (AEC), and changes in the total adenylate pool were observed in a 24-hr period even for the lowest concentration of pollutant tested. Field transfer experiments of C. edule from a safe zone to polluted areas of the Sado estuary were carried out at two different times of the year. Close proximity to sewage outfall was shown to result in significant decreases in AEC values within 24 hr. One week after transfer, either normal AEC values were found or the organisms died, depending on the location of the sampling station.     

Coordinated changes of adenylate energy charge and ATP/ADP: use in ecotoxicological studies

The coordinated variations of the adenylate energy charge and ATP/ADP ratio were modeled and a function that depends on the numerical value of the adenylate kinase-catalyzed reaction has been derived. The model allows sensitive detection of the effects of xenobiotics on adenylate kinase and its cellular environment and offers a robust estimation of the direct or indirect effects of pollutants on the adenylate kinase system: data obtained in laboratory studies on shrimp exposed to cadmium and in field studies on oysters either exposed to polychloro-biphenyl compounds or located in a heavily polluted area indicate that xenobiotics affect the adenylate kinase reaction directly or by changing its cellular environment. These results demonstrate that application of the model to the treatment of ecotoxicological data allows detection of energetic changes that would have been missed by simple analysis of the usual energetic parameters, and should overcome problems encountered in using energetic parameters during assessment of pollution monitoring.     

Effects of cadmium ingestion and food restriction on energy metabolism and tissue metal concentrations in mallard ducks (Anas platyrhynchos)

The single and combined effects of cadmium ingestion and food restriction were examined in a 42-day experiment with male, juvenile mallard ducks. A 2 X 3 factorial design was employed consisting of two levels of food supply (ad libitum and 55% of ad libitum intake) and three levels of cadmium in the food (0, 5, or 50 micrograms Cd/g food). Cadmium ingestion alone had no effect on body or tissue weights, liver glycogen, plasma concentrations of glucose, urea, uric acid, nonesterified fatty acids (NEFA), triiodothyronine (T3), thyroxine (T4), or plasma or adrenal concentrations of corticosterone. The food restriction resulted in reduced body weights and reduced weights of livers, kidneys, and testes, increased adrenal weights, reduced liver glycogen, increased plasma NEFA concentrations, reduced plasma T3 and T4 concentrations, and increased adrenal corticosterone concentrations. In combination with the food restriction, cadmium ingestion further reduced plasma T3 concentrations and a similar trend was noted for T4. Additionally, the highest plasma NEFA concentrations and highest plasma and adrenal concentrations of corticosterone were observed in food-restricted ducks receiving the highest level of dietary cadmium. These results suggest the ability of cadmium ingestion to enhance food restriction-induced alterations in energy metabolism at levels of dietary cadmium that are by themselves without apparent effect. Also, cadmium ingestion resulted in increased kidney concentrations of copper and zinc; this effect on kidney zinc concentrations was increased in food-restricted ducks.     

Effects of cadmium onMurex trunculus from the adriatic sea. II. Oxygen consumption and acclimation effects

Marine snails (Murex trunculus) from the Adriatic Sea were exposed to cadmium in the laboratory under chronic (0.05 mg·L^–1) and acute 5 mg·L^–1) conditions. More than 5 mg·L^–1 cadmium were required to lethally damageMurex trunculus during an exposure of 96 hr. Compared with untreated animals, chronic exposure ofMurex trunculus to 0.05 mg Cd·L^–1 results in an elevated rate of oxygen consumption. The difference between the two groups of snails increases with time. After one month, a 10% greater loss in biomass in treated animals than in controls was observed, reflecting the higher energy expenditure during exposure to 0.05 mg Cd·L^–1. An acute cadmium shock of 5 mg Cd·L^–1 caused depression of oxygen consumption both in the control and in long-term preexposed snails to 0.05 mg Cd·L^–1. If pre-exposure to a low (0.05 mg·L^–1) concentration of cadmium lasted for a short time only (18 hr) a subsequent acute cadmium shock (5 mg·L^–1) did not lead to a depression of the rate of oxygen consumption.     

Effects of the beta-agonist, cimaterol, on growth, body composition and energy expenditure in rats

1. Male Sprague-Dawley rats weighing 146.5 (SE 4.3) g were fed on a semi-synthetic diet containing 0, 25 or 150 mg cimaterol/kg for 12 d. Net changes in weight and composition of carcass, liver, heart, gastrointestinal tract, gastrocnemius plus plantaris muscles, skin and remainder were estimated by comparative slaughter. 2. Cimaterol increased protein gains in gastrocnemius plus plantaris muscles from 0.09 g in controls to 0.14 and 0.12 g in 25 and 150 mg cimaterol/kg groups respectively. Carcass protein gains increased from 6.27 g in controls to 8.00 and 7.05 g in 25 and 150 mg cimaterol/kg groups respectively. 3. Rats treated with cimaterol either gained less fat or actually lost fat from all tissues studied, whilst control rats gained fat. These changes were reflected in lower energy retention in cimaterol-fed rats. 4. Energy intake was not affected by treatment. Cimaterol increased heat production from 776 kJ/kg body-weight0.75 in controls to 863 kJ/kg body-weight0.75 in both treated groups. Gross efficiency was reduced from 17.4% in controls to 8.0 and 7.7% in rats fed on 25 and 150 mg cimaterol/kg diets respectively. 5. These results indicate that cimaterol increases protein gain at the expense of fat in rats. In addition, subcutaneous adipose tissue appears to be more sensitive than abdominal fat, whilst protein gains are particularly enhanced in skeletal muscle relative to other body tissues.     

Effects of supplemental ultraviolet-B and cadmium on growth, antioxidants and yield of Pisum sativum L

The impact of supplemental UV-B irradiation (sUV-B) and cadmium (Cd, 68 micromol kg(-1) soil) singly and in combination was studied on growth, pigments, enzymatic and non-enzymatic antioxidants, lipid peroxidation (LPO), uptake and translocation of Cd and yield of pea plants under field condition. Compared to the control, both the stresses individually and in combination led to in reductions in growth, photosynthetic pigments, ascorbic acid, catalase (CAT) activity and yield, whereas a reverse trend was observed for flavonoids, thiols and proline contents, superoxide dismutase (SOD) and peroxidase (POD) activities, and LPO. The uptake and translocation of Cd increased in different plant parts with duration of its treatment and also when applied with sUV-B. Combined treatment of sUV-B and Cd inhibited the growth and various metabolic processes antagonistically except the CAT activity which showed additive response. Further, CAT activity may be used as a bioindicator parameter to evaluate the individual and interactive effects of both the stresses.     

Effects of the interaction of sex and food intake on the relation between energy expenditure and body composition

BACKGROUND: The relation between physical activity energy expenditure (PAEE) and percentage body fat (%BF) is not very strong in the general population. It is possible that variables such as sex, food intake, or both may in part explain this poor coupling. OBJECTIVE: This study was designed to show the relation between PAEE and %BF and to determine whether sex, food intake, or both influence the strength of the relation. DESIGN: We used doubly labeled water or energy intake balance, indirect calorimetry, dietary interview, and dual-energy X-ray absorptiometry to measure total energy expenditure (TEE), resting energy expenditure (REE), food intake, and %BF, respectively, in 91 healthy persons (women: aged 48 y, 38.6%BF, n = 47; men: aged 47 y, 24.1%BF, n = 44). RESULTS: TEE, PAEE, and REE were significantly lower in women than in men. TEE was related to %BF in women (r = 0.53, P < 0.0001) but not in men (r = -0.22, P > 0.05). The relation between PAEE and %BF was significant in men (r = -0.34, P < 0.03) but not in women. PAL was also significantly related to %BF in men (r = -0.36, P < 0.02) but not in women. Macronutrient intake (% of total energy) did not differ significantly between the sexes, but carbohydrate (r = -0.44, P < 0.003) and fat (r = 0.31, P < 0.04) intakes were significantly related to %BF in women. CONCLUSIONS: These results suggest that the relation between PAEE and %BF is stronger in men than in women. Macronutrient composition seems have a stronger influence on %BF in women than in men.     

Effects of cadmium on microorganisms

A short review was made of current knowledge, particularly of experimental and laboratory studies, relating to cadmium toxicity on microorganisms. The survey includes several aspects of cadmium toxicology, such as growth inhibition, lethality, physiological alterations, microbial resistance to cadmium, uptake, and bioaccumulation. The spectrum of heavy metal toxicity on microorganisms involves initial growth inhibition up to the total elimination of a microbial population, and includes alterations of morphology, e.g., mitochondria, Golgi, and ribosomes as probable sites of damage, of metabolic pathways or enzymatic activities. Heavy metals may cause cytostatic or mutagenic effects, as described for Salmonella spp. and Escherichia coli. Microorganisms have the potential to accumulate and deposit heavy metals without showing adverse effects, to develop mechanisms of resistance, and to adapt to increasing concentrations of heavy metals.     

Effects of energy or protein restriction on weight and composition of diabetic and control rats

Adult (170 ± 1 g) male Sprague-Dawley diabetic (50 mg/kg of streptozotocin) and control rats were fed for 21 days a diet with adequate protein (28%) at three restricted levels of intake (34, 45 or 57 kcal/day), or were fed at a single level of intake (ad libitum) diets containing different percentages of protein (2.25, 5.5 and 11.1). When dietary protein was adequate (28%), but energy intake was severely restricted (34 kcal/day), diabetic and control rats lost 80 ± 5 and 100 ± 6 g/kg ^0.75 in body weight, respectively. Diabetic and control rats lost 110 ± 4 and 139 ± 7 g/kg ^0.75 in body weight, respectively, when energy was unrestricted and dietary protein was at a submaintenance level (2.25%). Body weight of diabetic and control rats did not differ when dietary protein was adequate (28%) and energy intake was moderately restricted (45 kcal/day) or when energy intake was unrestricted and dietary protein was at a maintenance level (5.5%). This study showed that diabetic rats fared as well as or better than their control counterparts when the intake of either energy or protein was moderately or severely restricted.