Sublethal effects of hypoxia in the abalone (Haliotis rufescens) as measured by in vivo31P NMR spectroscopy

• 1.1. Effects of hypoxia were investigated in red abalones (Haliotis rufescens) using a flow-through exposure system and in vivo³¹P NMR spectroscopy.
• 2.2. Following seawater acclimation, abalones were exposed to air for 1 hr, then seawater for 2.5 hr to check recovery; parallel controls were performed without air exposure.
• 3.3. In foot muscle, hypoxia produced a decrease in phosphoarginine concentration and intracellular pH, an increase in inorganic monophosphate concentration, and no change in that of ATP; upon resubmergence, all effects generally recovered.
• 4.4. The changes induced by hypoxia during normal tidal changes are consistent with the blockage of mitochondrial oxidative phosphorylation.
• 5.5. Use of in vivo NMR allows measurement of the biochemical effects of natural stress factors in live, intact aquatic organisms in the laboratory.

     

Immobilization stress-induced antioxidant defense changes in rat plasma: Effect of treatment with reduced glutathione

• 1.1. We examined immobilization stress-induced antioxidant defense changes in rat plasma and observed the antioxidant effect of reduced glutathione (GSH) administration on these changes.
• 2.2. Immobilization stress induced severe bleeding in the stomach and a significant increase in plasma levels of thiobarbituric acid receives substances (TBARS).
• 3.3. Immobilization stress induced a significant decrease in plasma iron-binding, ironoxidizing protections and radical scavenging activity.
• 4.4. Plasma levels of ascorbic acid, ascorbyl radical and superoxide dismutase activity remained unchanged following immobilization stress.
• 5.5. Treatment with GSH showed a significant protective effect on stomach bleeding, on the increase in plasma TEARS, and on the decrease of iron-binding, iron-oxidizing protection and radical scavenging activity in plasma.
• 6.6. These results suggest that immobilization stress induces generation of reactive oxygen species and decreases the endogenous antioxidant defenses, which can be attenuated by extracellular administration of antioxidant GSH.

     

Bioavailability of organic chemicals in the aquatic environment

• 1.1. Bioavailability in the aquatic environment can be defined as the external availability of a chemical to an organism. The availability of sediment-sorbed chemicals to organisms is a particularly important aspect of this phenomena.
• 2.2. Various experiments described in the literature, such as toxicity and accumulation experiments, have investigated the influence of suspended sediment in the aqueous phase on bioavailability.
• 3.3. The bioavailability of a chemical appears to be influenced by the chemical, the sediment, and the organism being examined. Thus, describing “the bioavailability” of a chemical in the aquatic environment is not a simple process.

     

Physiological costs of combating chemical toxicants: Ecological implications

• 1.1. Evidence is presented that combating the poisoning effects of toxic chemicals is metabotically costly.
• 2.2. This has implications for relating physiological stress responses observed at the level of individual organisms to population effects, and needs to be incorporated explicitly into models making this link.
• 3.3. The cost hypothesis also has implication for the evolution of stress resistance either as a fixed or facultative (inducible) response. Optimization models incorporating these ideas are reviewed and discussed.

     

Does carnosine possess direct antioxidant activity?

• 1.1. A brief review of development of ideas of the antioxidant activity of carnosine and related compounds is presented.
• 2.2. An analysis of the behaviour of carnosine in different models of free radical chain reactions shows that carnosine is a potent hydrophylic antioxidant of a direct non-enzymatic action.
• 3.3. It is characteristic of the higher activity of interaction with active hydroxyl radical.
• 4.4. However the known biological effects of carnosine cannot be explained only by its anti-oxidant properties.

     

Metabolic and contractile differentiation of rabbit muscles during growth

• 1.1. A study was carried out of post-natal evolution of the oxidative, glycolytic and contractile capacities in various types of rabbit muscle.
• 2.2. At birth, muscles are non-differentiated and present very limited metabolic and contractile activity, metabolism is mainly oxidative in all muscles.
• 3.3. Although muscular discrimination is manifest from the sixth week after birth, the glycolytic metabolism reaches its maximum capacity only after six to eight weeks.
• 4.4. Subsequently, oxidative metabolic capacity steadily decreases until adulthood.

     

Dietary supplementation of vitamin E fails to prevent the development of hyperoxic lung injury in the premature guinea pig

• 1.1. The benefit of dietary vitamin E supplementation in preventing oxidative-induced lung injury was investigated. Three day preterm guinea pig pups were exposed to hyperoxic (85% O₂) or normoxic (21% O₂) conditions. The animals were fed either a standard low birthweight human infant formula milk (6.4 mg/l vitamin E), or a vitamin E supplemented milk (100 mg/l) for up to 7 days.
• 2.2. After 3 days vitamin E supplementation, plasma but not erythrocyte vitamin E concentrations were elevated, while following 7 days both plasma and erythrocyte vitamin E concentrations were significantly increased.
• 3.3. Lung and liver vitamin E concentrations were elevated at both 3 and 7 days. At 3 days the increase in lung vitamin E was oxygen-dependent, suggesting that the lung increases uptake of vitamin E in response to oxidative stress.
• 4.4. Despite an increase in the vitamin E concentration of the lungs of preterm guinea pigs, no amelioration of the lung injury was observed. These results suggest that although vitamin E is a potent antioxidant, it is unable to protect adequately the lungs from reactive oxygen species in the absence of sufficient primary enzymatic antioxidant defences.

     

Seasonal variations in the antioxidant defence systems and lipid peroxidation of the digestive gland of mussels

• 1.1. The seasonal variations in the level of antioxidant compounds (glutathione (GSH), vitamin E, carotenoids) and in the activity of antioxidant enzymes, Superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6), GSH-peroxidase (EC 1.11.1.9) in the digestive gland of mussels (Mytilus sp.) were evaluated. The lipid peroxidation process was also measured by determining the tissue concentration of malondialdehyde (MDA).
• 2.2. The physiological fluctuations of the antioxidant defence systems were inversely related to the accumulation of lipid peroxidation products (MDA) in the tissue. The observed seasonal variations are presumably related to the changing metabolic status of the animals, itself dependent on such factors as gonad ripening and food availability.
• 3.3. In particular, the obtained data indicate that a reduction of the antioxidant defence systems, occurring during winter, could be directly responsible for an enhanced susceptibility of mussels tissues to oxidative stress, as indicated by the high MDA concentration observed in this period.

     

Stratophenetic analysis of avascular necrosis in turtles: Affirmation of the decompression syndrome hypothesis

• 1.1. The decompression syndrome hypothesis, as an explanation of the etiology of avascular necrosis, is further substantiated through analysis of its occurrence in turtles.
• 2.2. No examples were identified in terrestrial or aquatic forms diving to depths insufficient for development of decompression syndrome.
• 3.3. The “population” frequency of avascular necrosis has substantially diminished over geologic time.
• 4.4. A frequent occurrence in Cretaceous marine turtles, it is only rarely observed in specimens younger than Miocene age.
• 5.5. Evolution of physiologic and/or behavioral protective mechanisms appears to be responsible for reduced susceptibility to the underlying decompression syndrome.

     

Response to stress of mussels (Mytilus edulis) exposed in dutch tidal waters

• 1.1.Mussels were exposed in the Dutch coastal zone and the Western Scheldt estuary. After six weeks of exposure, trace metals, PCBs and PAHs were measured in the soft tissue.
• 2.2. Tissue concentrations of contaminants are high in the Western Scheldt and intermediate near the Rhine outflow, except for the lower PCB congeners.
• 3.3. Results show that the survival in air is significantly lower at higher tissue concentrations, in particular of the lower PCB congeners.
• 4.4. The clearance rate is reduced at the highest tissue concentrations.

     

Purification and partial characterization of an AMP deaminase from the marine invertebrate Palaemon serratus

• 1.1. AMP deaminase from Palaemon serratus tail muscle was partially purified by chromatography on cellulose phosphate.
• 2.2. Muscle homogenates expressed very low enzyme activities and the presence of ATP was necessary to detect AMP deaminase. The specific activity and substrate affinity of the purified enzyme were also very low.
• 3.3. The purified prawn muscle AMP deaminase was contaminated by contractile proteins, one of the major contaminants being actin.
• 4.4. The enzyme displayed a very high affinity for actomyosin which was only partially abolished by pyrophosphate.

     

Breast,hips, and buttocks revisited: Honest fatness for honest fitness

This paper comments on: Low, B. S., Alexander, R. D., and Noonan, K.M. Human hips, breast, and buttocks: Is fat deceptive? Ethology and Sociobiology 8: 249-247, 1987. In it I argue that:

• 1.1. Sexual selection has probably not been the most important selection pressure on
• 2.female human body shape.
• 3.2. Male humans in different cultures find different aspects of the female body attractive
• 4.and therefore are unlikely to have exerted consistent directional sexual selection on
• 5.the female body.
• 6.3. Breast size is not correlated with lactation success.
• 7.4. Visible hip width is not correlated with parturition success.
• 8.5. Women would lower their fitness if they tried to deceive men about their internal
• 9.pelvic dimensions.
• 10.6. There are many alternative hypothesis to explain the existence of fat onwomen's
• 11.breast, hips, and buttocks.

     

Flight effects on certain blood parameters in homing pigeons Columba livia

• 1.1. Various blood parameters were monitored in resting and flown homing pigeons. A homing flight of 48 km lasting 60–80 min did not significantly alter plasma levels of total protein, electrolytes and plasma osmolality, which indicated maintenance of the homeostatic stability of the internal milieu during moderate exercise.
• 2.2. Plasma concentrations of marker enzymes such as alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), laetate dehydrogenase (LDH) and creatine phosphokinase (CPK) that tend to denote muscle damage and metabolic flux in prolonged exercise, were also not altered, thereby indicating the steady state of tissue structure and function during a flight of this magnitude.
• 3.3. Significant increases in plasma levels of uric acid and creatinine and decreases in plasma albumin were observed in the flown pigeons.
• 4.4. The flight-induced increase in blood uric acid could be attributed to increased purine catabolism and the increase in creatinine to increased nucleotide turnover.
• 5.5. It is suggested that the higher uric acid levels should not only enhance water conservation, but may also reduce flight-induced hyperthermia besides acting as an antioxidant defence against oxidative tissue injury.
• 6.6. The rise in creatinine is indicative of the breakdown of phosphocreatine for energy during the initial period of flight prior to the utilization of carbohydrate and lipid as fuels.
• 7.7. The decrease in plasma albumin should account for the albumin as lipid carrier lost in transport to the muscles during flight.

     

Activation of neutrophils NADPH oxidase by PMA: Cytosol activity is translocated in phorbol-primed neutrophils

• 1.1. Translocation of cytosol activity in phorbol-primed neutrophils was studied.
• 2.2. Prior exposure of PMA or FMLP could potentiate the oxidative response by subsequent heterogeneous stimulus, FMLP or PMA.
• 3.3. In FMLP-primed neutrophils, the cytosol had almost the same activity as resting one and cytosol activity was not eluted from the membrane.
• 4.4. In PMA-primed neutrophils, however, the cytosol had less activity and cytosol activity was correspondingly eluted from the membrane.
• 5.5. These observations suggested that cytosol activity was translocated in PMA-primed cells.

     

Fiber type composition and enzyme activities of muscles in two models of obese rats

• 1.1. In oxidative (soleus) and glycolytic (extensor digitorum longus) muscles of obese Zucker rats, a significant decrease in the percentage of relative area occupied by glycolytic fibers was observed.
• 2.2. The activity of citrate synthase and β-hydroxy-acyl-CoA-dehydrogenase was significantly higher in muscles of obese than of lean Zucker rats.
• 3.3. In rats, 6 weeks after lesion of the ventromedial hypothalamus, no changes were observed.
• 4.4. This indicates that neither the proportion of oxidative fibers, nor the oxidative capacities are decreased in skeletal muscles of obese rats suggesting that insulin resistance cannot be ascribed to a higher glycolytic-oxidative fiber ratio.

     

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Role of physiological energetics in ecotoxicology

• 1.1. The role of physiological energetic measurements combined with chemical analyses of contaminants in body tissues of mussels in fundamental toxicological studies and pollution monitoring programmes is outlined.
• 2.2. Important features of this toxicological approach are briefly reviewed, including aspects of bioaccumulation, sensitivity, quantitative concentration-response relationships, QSARs, mechanistic interpretation, ecological relevance, integration of the consequences of multiple mechanisms of toxicity and effects of contaminant mixtures and application to laboratory and field studies.
• 3.3. This review focuses particularly on recent advances in understanding and predicting the effects of complex mixtures of contaminants.

     

Investigations of phagocytosis concerning the immunological defence mechanism of Mytilus edulis using a sublethal luminescent bacterial assay (Photobacterium phosphoreum)

• 1.1. A simple method for the determination of phagocytosis activity using mussel hemocytes by measuring the bioluminescence is presented.
• 2.2. The immunological defence activity based on phagocytosis is measured and quantified by a luminescent bacterial assay with Photobacterium phosphoreum.
• 3.3. The measuring system allows us to establish the stress of the immunological defence mechanism of organisms exposed to chemicals and polluted rivers or sewage. Results with reference substances and the phagocytosis indices of exposed mussels from Norwegian aquaculture plants compared to those of mussels from the German Wadden Sea are given as examples.

     

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