Plasmalogens in the gill lipids of aquatic animals

Lipids constituted 0.6-2.2% wet wt of the gills of 11 species of aquatic animals (4 bivalves, a crustacean and 6 fishes). Phospholipids, largely phosphatidylcholine (PC) and phosphatidylethanolamine (PE), are major components of all species. The plasmalogen contents of these lipids were 47-291 mumol/g, with the highest values found for bivalve gill total lipids and the catfish phospholipid fraction.     

Oxidants and antioxidants in aquatic animals

• 1.1. Oxidative stress, potentially, is experienced by all aerobic life when antioxidant defenses are overcome by prooxidant forces, and is the basis of many physiological abberations.
• 2.2. Environmental contaminants may enhance oxidative stress in aquatic organisms, e.g. highly elevated rates of ideopathic lesions and neoplasia among fish inhabiting polluted environments is increasingly related to oxidative stress associated with environmental pollution.
• 3.3. Metabolism of redox cycling xenobiotics in aquatic organisms is very similar to that of mammals suggesting similarities in the health consequences of exposure to such compounds.
• 4.4. The expression of specific lesions known to arise specifically from oxidative stress, e.g. lipid peroxidation, oxidized bases in DNA and accumulation of lipofuscin pigments are present in many aquatic animals exposed to contaminants.
• 5.5. Aquatic organisms contain the major antioxidant enzymes SOD, catalase and glutathione peroxidase, albeit there are marked quantitative differences among the various species reported.

     

Oxidants and antioxidants in aquatic animals.

1. Oxidative stress, potentially, is experienced by all aerobic life when antioxidant defenses are overcome by prooxidant forces, and is the basis of many physiological abberations. 2. Environmental contaminants may enhance oxidative stress in aquatic organisms, e.g. highly elevated rates of ideopathic lesions and neoplasia among fish inhabiting polluted environments is increasingly related to oxidative stress associated with environmental pollution. 3. Metabolism of redox cycling xenobiotics in aquatic organisms is very similar to that of mammals suggesting similarities in the health consequences of exposure to such compounds. 4. The expression of specific lesions known to arise specifically from oxidative stress, e.g. lipid peroxidation, oxidized bases in DNA and accumulation of lipofuscin pigments are present in many aquatic animals exposed to contaminants. 5. Aquatic organisms contain the major antioxidant enzymes SOD, catalase and glutathione peroxidase, albeit there are marked quantitative differences among the various species reported.     

Cestode zoonoses of aquatic animals

The cestode zoonoses of Diphyllobothrium, and Spirometra and Sparganosis are discussed from the point of view of their transmission and epidemiology.     

Tool use by aquatic animals

Tool-use research has focused primarily on land-based animals, with less consideration given to aquatic animals and the environmental challenges and conditions they face. Here, we review aquatic tool use and examine the contributing ecological, physiological, cognitive and social factors. Tool use among aquatic animals is rare but taxonomically diverse, occurring in fish, cephalopods, mammals, crabs, urchins and possibly gastropods. While additional research is required, the scarcity of tool use can likely be attributable to the characteristics of aquatic habitats, which are generally not conducive to tool use. Nonetheless, studying tool use by aquatic animals provides insights into the conditions that promote and inhibit tool-use behaviour across biomes. Like land-based tool users, aquatic animals tend to find tools on the substrate and use tools during foraging. However, unlike on land, tool users in water often use other animals (and their products) and water itself as a tool. Among sea otters and dolphins, the two aquatic tool users studied in greatest detail, some individuals specialize in tool use, which is vertically socially transmitted possibly because of their long dependency periods. In all, the contrasts between aquatic- and land-based tool users enlighten our understanding of the adaptive value of tool-use behaviour.     

水生动物的争胜行为

同种动物个体相遇争斗的行为称为争胜行为。这是一种典型的社会行为,广泛存在于各类水生动物中,其目的是确定优势(统治)地位和从属关系。该文针对争胜行为的表现形式、影响因素、以及发生机制进行了综述,分析了争胜行为的研究现状及发展趋势,以期为水生动物争胜行为的研究提供借鉴和参考,并为促进我国水产养殖业的发展提供理论依据。     

Flow-through polarographic respirometry for aquatic animals

Summary A polarographic method of measuring oxygen consumption of aquatic animals, which is based upon expanding the input signal to a potentiometric recorder, has been described. This gives a magnified visual tracing that can be measured with the polar planimeter and related proportionately to the oxygen concentration to accurately measure the metabolism of aquatic animals with wet body weights of 5 mg or more. Changes in oxygen utilization of 0.04 per cent concentration of oxygen are readily visible, and results are reproducible.

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Zusammenfassung Eine polarographische Methode der Bestimmung des O₂-Verbrauches von Wassertieren, die auf der Verstarkung des Eingangstrom zum Potentiometer basiert ist, ist beschrieben worden. Dies erzeugt eine vergrößerte sichtbare Kurve. Der Flächeninhalt unter dieser Kurve kann mit einem Flächenmesser gemessen werden, und diese Flächeninhalt läßt sich direkt proportional auf der O₂- Konzentration beziehen, sodaß das Metabolismus von Wassertieren mit Naßgewicht von 5 mg. oder mehr genau gemessen werden kann. Änderungen der O₂-Ausnutzung von 0,04% O₂-Konzentration sind ohne weiteres bestimmbar, und Resultate können dupliziert werden.

     

Nitrite disrupts multiple physiological functions in aquatic animals

Nitrite is a potential problem in aquatic environments. Freshwater fish actively take up nitrite across the gills, leading to high internal concentrations. Seawater fish are less susceptible but do take up nitrite across intestine and gills. Nitrite has multiple physiological effects. Its uptake is at the expense of chloride, leading to chloride depletion. Nitrite also activates efflux of potassium from skeletal muscle and erythrocytes, disturbing intracellular and extracellular K(+) levels. Nitrite transfer across the erythrocytic membrane leads to oxidation of haemoglobin to methaemoglobin (metHb), compromising blood O(2) transport. Other haem proteins are also oxidised. Hyperventilation is observed, and eventually tissue O(2) shortage becomes reflected in elevated lactate concentrations. Heart rate increases rapidly, before any significant elevations in metHb or extracellular potassium occur. This suggests nitrite-induced vasodilation (possibly via nitric oxide generated from nitrite) that is countered by increased cardiac pumping to re-establish blood pressure. Nitrite can form and/or mimic nitric oxide and thereby interfere with processes regulated by this local hormone. Steroid hormone synthesis may be inhibited, while changes in ammonia and urea levels and excretion rates reflect an influence of nitrite on nitrogen metabolism. Detoxification of nitrite occurs via endogenous oxidation to nitrate, and elimination of nitrite takes place both via gills and urine. The susceptibility to nitrite varies between species and in some cases also within species. Rainbow trout fall into two groups with regard to susceptibility and physiological response. These two groups are not related to sex but show significant different nitrite uptake rates.     

Genome mapping in aquatic animals: progress and future perspectives

The genome of aquatic animals is poorly understood and information from different taxonomic groups is sketchy. While there have been intensive genomic studies on some fish models, investigations on other fishes and invertebrates have been scarce. Yet there are recently some coordinated studies on genome mapping in a number of aquaculture animals of economic importance. This review summarizes information available on genome mapping of the important fish models and aquaculture animals. The future perspectives of this field of studies are discussed.     

Glutathione transferases in aquatic and terrestrial animals from nine phyla

Glutathione transferase (GST) was present in 71 of 72 animal species/stages representing nine phyla when measured with 1-chloro-2,4-dinitrobenzene (CDNB). Our hypothesis that all animals have GST was not falsified. Transferase activity towards ethacrynic acid (ETHA) was present in species from all phyla investigated, but some animals seem to be without this activity. Activity towards 1,2-dichloro-4-nitrobenzene (DCNB) was less developed in aquatic animals than in terrestrial ones. The amount of protein binding to GSH-affinity gel matrix was rather uniform, ranging between 0.3 and 0.7% of soluble protein in homogenates of widely diverse animal species, thus being less variable than the enzyme activity. Transferases active towards DCNB did not bind at all or were less firmly bound to the GSH-affinity gel than the activity towards CDNB or ETHA. Fractionation was obtained by using a gradient of GSH. With SDS-electrophoresis it was demonstrated that the proteins with affinity to GSH had monomers in the MW-range 21.500-29.000. Hydra attenuata had one band (MW = 25,000); all other sources gave a complex pattern with up to six bands. It is concluded that GSTs are characteristic major constituents of animal cells, probably with some common basic function. Mutant forms able to aid detoxication are retained in the phylogenesis when they increase the fitness of the animal.     

Ecology and welfare of aquatic animals in wild capture fisheries

The expansion of commercial aquaculture production has raised awareness of issues relating to the welfare of aquatic animals. The “Five Freedoms” approach to animal welfare was originally devised for farmed terrestrial animals, and has been applied in some countries to aquatic animals reared in aquaculture due to several commonalities inherent within food production systems. There are now moves towards assessing and addressing aquatic animal welfare issues that may arise in wild capture fisheries. However, all “five freedoms” are regularly contradicted in the natural environment, meaning this concept is inappropriate when considering the welfare of aquatic animals in their natural environments. The feelings-based approach to welfare relies on a suffering centered view that, when applied to the natural aquatic environment, requires use of value judgements, cannot encompass scientific uncertainty regarding awareness in fish, elasmobranchs and invertebrates (despite their unquestioned welfare needs), and cannot resolve the welfare conundrums posed by predator–prey interactions or anthropocentrically mediated environmental degradation. For these reasons, the feelings-based approach to welfare is inadequate, inappropriate and must be rejected if applied to aquatic animals in wild capture fisheries, because it demonstrably ignores empirical evidence and several realities apparent within the natural aquatic environment. Furthermore, application of the feelings-based approach is counterproductive as it can alienate key fisheries stakeholders, many of whom are working to address environmental issues of critical importance to the welfare, management and conservation of aquatic animal populations in their natural environment. In contrast, the function-based and nature-based approaches for defining animal welfare appear appropriate for application to the broad range of welfare issues (including emerging environmental issues such as endocrine disruption) that affect aquatic animals in their natural environment, without the need to selectively ignore groups such as elasmobranchs and invertebrates. We consider that the welfare needs of aquatic animals are inextricably entwined with the need for conservation of their populations, communities and their environment, an approach that is entirely consistent with the concept of ecosystem-based management.     

Plasmalogens in the yeast Pullularia pullulans

Choline and ethanolamine phosphoglycerides have been found in plasmalogen form in P. pullilans. Plasmalogens had not been described in yeasts up to now.     

Determination of residues of malachite green in aquatic animals

Residues of malachite green (MG) were extracted from homogenized animal tissues with a mixture of McIlvaine buffer (pH 3.0)-acetonitrile, and purified over an aromatic sulfonic acid solid-phase extraction column followed by HPLC or LC-ESI-MS-MS analysis. Ascorbic acid and N,N,N',N'-tetramethyl-1,4-phenylenediamine dihydrochloride were added to reduce de-methylation of the dye. Responses were recorded at 620 nm (HPLC) or by multiple-reaction-monitoring (LC-MS-MS) after post-column oxidation using PbO(2). MG and its primary metabolite leuco-malachite green (LMG) were successfully determined at 2.5-2000 microg/kg in catfish, eel, rainbow trout, salmon, tropical prawns and turbot, with a limit of detection at 1 microg/kg (HPLC) and 0.2 microg/kg (LC-MS-MS) for both MG and LMG. Recoveries for LMG were between 86+/-15% (prawn) and 105+/-14% (eel). Freeze-thawing cycles, and storage at 4 degrees C and -20 degrees C affected the recovery of both MG and LMG. Analyses of eel, trout and (processed) salmon field samples collected at local retailers, fish-market and -shops demonstrated trace levels of MG-residues.     

Comparative approaches to understand metal bioaccumulation in aquatic animals

Over the past decades, comparative physiology and biochemistry approaches have played a significant role in understanding the complexity of metal bioaccumulation in aquatic animals. Such a comparative approach is now further aided by the biokinetic modeling approach which can be used to predict the rates and routes of metal bioaccumulation and assist in the interpretation of accumulated body metal concentrations in aquatic animals. In this review, we illustrate a few examples of using the combined comparative and biokinetic modeling approaches to further our understanding of metal accumulation in aquatic animals. We highlight recent studies on the different accumulation patterns of metals in different species of invertebrates and fish, and between various aquatic systems (freshwater and marine). Comparative metal biokinetics can explain the differences in metal bioaccumulation among bivalves, although it is still difficult to explain the evolutionary basis for the different accumulated metal body concentrations (e.g., why some species have high metal concentrations). Both physiological/biochemical responses and metal geochemistry are responsible for the differences in metal concentrations observed in different populations of aquatic species, or between freshwater and marine species. A comparative approach is especially important for metal biology research, due to the very complicated and potentially variable physiological handling of metals during their accumulation, sequestration, distribution and elimination in different aquatic species or between different aquatic systems.     

Carbon dioxide fixation in aquatic animals and its metabolic significance]

In experiments on the carp Cyprinus carpio and freshwater lamellibranch mollusc Anodonta cygnea, tissue and organ peculiarities of carboxylic reactions have been revealed together with their relationship to the temperatute and ionic composition of the incubation medium. It was shown that in fish the highest intensity of fixation of CO2 is exhibited by glandular organs with biosynthetic profile of the metabolism (liver), whereas in molluscs it is exhibited in the mantle which plays the key role in the formation of the shell, containing carbonate compounds of calcium.