Die stickstoffhaltigen stoffwechselendprodukte und ihre exkretion bei Paracentrotus lividus

The perivisceral fluid of Paracentrotus lividus (Lamarck) contains, as main end-products of the nitrogenous metabolism, ammonia, urea, creatine, creatinine and traces of uric acid. In the organs analysed, the distribution and abundance of ammonia and urea fluctuate considerably. the intestine was found to have the highest NH₄ ⁺?N and the lowest urea-N contents. The axial organ contained the highest amount of urea-N and the lowest quantity of NH₄ ⁺?N; the perivisceral fluid, including the coelomocytes, contained intermediate amounts. The special relations to hemal system and coelothel, the presence of excretory material, and the analogous conditions to other invertebrates, suggest that the coelomocytes and parts of the intestine and axial organ are excretophoric and able to synthesize urea. From the known distribution of ammonia and urea in echinoid species, it is concluded that the ability to synthesize urea must have developed and improved in efficiency during echinoid evolution. P. lividus is predominantly ureotelic. It excretes approximately 91% of the nitrogenous wastes released into the surrounding sea water as urea-N, and only 9% as ammonia-N. Ammonia, and most of the urea, are excreted via the body surface — probably through respiratory surfaces; however, one third of the urea is excreted through the intestine, since urea excretion decreases by this amount when the anus is sealed artificially.     

Die Fungizide Hexachlorbenzol und Pentachlornitrobenzol und ihre Stoffwechselwege

Die Kenntnis biochemischer Veränderungen von lipophilen körperfremden Stoffen ist hinsichtlich deren Elimination aus dem Organismus, sowie bei Überlegungen zur Voraussage toxischer, insbesondere carcinogener Wirkungen von vorrangiger Bedeutung     

Schwermetallbelastung von Dreissena polymorpha in Donau und Drau und ihre Bedeutung als Bioindikator

Goal and Scope

This study was undertaken to investigate the differences in heavy metal burden between the organisms and environmental compartments and to evaluate the role of Dreissena polymorpha as a bioindicator organism.

Methods

The concentrations of zinc, copper, cadmium and lead in whole soft body and selected tissues of D. polymorpha at two river habitats in Austria were examined using atomic absorption spectroscopy (AAS). Concentrations in organisms were compared to those in sediment and water.

Results and Conclusion

Zebra mussels of the river Drau showed generally higher heavy metal concentrations as compared to mussels of the river Danube and contained elevated zinc and cadmium levels as compared to metal concentrations found in soft tissues of zebra mussels from uncontaminated sites in Germany and The Netherlands. The essential metals zinc and copper were mainly accumulated in gills, foot and byssal gland tissue of the mussel, in contrast to the non-essential metals cadmium and lead which were found predominantly in the midgut gland. The heavy metal concentrations in both, sediments and mussel tissue, were higher than in water samples. There was no correlation between the concentrations in water and in the organisms except for zinc. In contrast, correlations were found between concentrations in sediments and mussel soft tissue.

Recommendation and Perspective

Further investigations should include the examination of sediments and consider the mechanism of food uptake to assess the role of D. polymorpha as a bioindicator organism.     

Salzgehalt und Photosynthese bei marinen Pflanzen

Marine plants — phanerogams as well as algae — show a proportional decrease of photosynthetic rate, when the salinity is lowered by dilution with distilled water. Using natural water instead of distilled water, it is absolutely indispensable to take into consideration the carbon supply. Normally, the photosynthetic rate decreases in freshwater with low alcalinity, in comparison to marine water. On the other hand, using water with high contents of bicarbonates, assimilation rate is higher than in marine water. These results show that salinity may indirectly affect photosynthesis due to differences in carbon supply. The direct influence is caused by exosmosis in hypotonic media and is irreversible. — The author cannot but agree with the statement by Ogata and Matsui (1965): “It may generally be said that the changes in salinity, osmotic pressure, pH, and also carbon dioxide supply, particularly in natural sea-water, are rather inseparably associated.”     

Spermatozeugmen und Paarungsverhalten bei Tripedalia cystophora (Cubomedusae)

New observations on the complete life cycle of Tripedalia cystophora Conant have revealed that—because of the radialsymmetrically constructed body of the polyp and its complete metamorphosis into one medusa—the “Cubozoa” are unique in their development, systematics and evolution. the same is true for the sexual biology of their medusae. It has long been known that the female T. cystophora are larviparous; fertilized eggs develop within the gastral pockets into free-swimming planulae. How do spermatozoa approach the eggs inside the female? In laboratory cultures, young medusae could be raised to maturity. Rearing experiments and observations yielded surprising results, revealing a situation which is new for Cnidaria. In T. cystophora, ripe medusae of both sexes can be identified easily by the different colour and structure of the gonads. In the gonads of the ripe male, numerous spermatozoa are joined to form spermatozeugmata of a simple type. Numerous spermatozeugmata form big globular bodies (spermatophores), which develop in small grooves on the inside surface of the stomach. The spermatophores are transferred directly from the male to the female during successive steps of special mating behaviour. The observations confirm that Cubomedusae have reached the peak of medusan specialization.     

Verteilungskoeffizienten chlorierter Kohlenwasserstoffe zwischen Muskulatur und Leber bei Fischen

Measured partition coefficients (KL_M/L) related to lipid-concentrations between the muscle (C_ML) and liver (C_LL) tissue of two fish species (Abramis brama, Zoarces viviparus) exhibit nominal values of unity according the relationship KL_M/L=C_ML/C_LL=1 for persistent compounds such as highly chlorinated PCB and values above one for degradable compounds for example chlorinated cyclohexanes or DDT. The corresponding theory is presented. The relationship holds for samples for single fish as well as for pooled samples.     

Kombinierte Wirkung von UV-Strahlung und xenobiotika bei zweiSaccharomyces-Stämmen

The effects of eight chemicals on the inactivation rate of ultraviolet radiation on the colony building capabilities of two strains of Saccharomyces cervisae — a wild type strain and a mutant deficient in excision repair — were studied. The insecticide methoxychlor, the herbicide 2,4-dichlorophenoxyacetic acid, the fungicide pentachlorophenol and its metabolite tetrachlorohydroquinone, as well as the chemicals acrylonitrile and 2,3-dichloro-1-propene have no significant impact on the effects of UV radiation inSaccharomyces cerevisae. Depending on the concentration, trichloroethylene increases the sensitivity to UV radiation. The herbicide paraquat provides efficient protection against UV radiation at concentrations where a toxic effect cannot be observed even without UV. The results were rather similar for both strains.     

Zur Morphologie,Histochemie, Tagesperiodik und Biologie der Operculardrüse bei Labriden und Scariden (Pisces)

A mucous gland is described, which is responsible for the production of the slime envelope in scarids and labrids. For this gland the name ‘opercular gland’ is suggested. The gland is developed, to a greater or lesser extent, in most of the genera examined. Morphological and histochemical studies indicate that the form of the gland is characteristic of the genus. Labrids and scarids can be divided, histochemically, into 3 groups: (1) opercular gland secretes only neutral MPS; (2) opercular gland secretes both neutral and weakly acidic MPS; (3) opercular gland secretes neutral MPS, weakly acidic and strongly acidic MPS (the strongly acidic MPS are probably sulphated). Species are found in all 3 groups with granular cells which secrete a tyrosine containing glycoprotein. The fish can be made to produce the mucous envelope by stimulation of the parasympathetic nervous system using pilocarpine. It is, therefore, assumed that the gland is controlled by the nervous system. Morphological studies of the gland show that the mucous is normally synthesised only in the evening, i.e. when it is needed; no storage takes place. Continuous light experiments have shown the gland to possess an endogenous rhythm of the same frequency as the fish's activity rhythm. Even those labrids which sleep under sand produce mucous. The average area of the longitudinal section of an opercular gland cell is more than 500 µ² in those species which produce a complete envelope, and usually somewhat less in the other species examined. The possible importance of the opercular gland in taxonomical and phylogenetical studies is discussed.     

Einfluß von Benetzungsspannung und lonen auf die Substratbesiedlung und das Einsetzen der Metamorphose bei Bryozoenlarven (Bowerbankia gracilis)

Settlement and metamorphosis in larvae of Bowerbankia gracilis depend on the wettability of the substratum. The wettability of a solid can be characterized by it's specific contact angle, . Larvae settle on solids with angles >17°, but not on surfaces with high wettability properties. In an attempt to explain this phenomenon, we consider the larvae as a second liquid and their attachment as a second wetting. In such case, water and larvae would compete in wetting the substratum. Adhesion can be accounted for by assuming the wetting tension of solid to water to be lower than that of the larval surface (|_solid/water| < |_solid/larvae|). Adhesion would thus be favoured energetically. The rate of settlement and that of metamorphosis are demonstrated as depending on the degree of contact angle, , in an all-or-none fashion. Settlement of larvae on high-wetting solids is prevented by high capillary pressure accruing at the point of contact. Metamorphosis is initiated by contractions occurring after adhesion. Application of CsCl or KCl induces such contractions and metamorphosis in free-swimming larvae. MgCl₂ prevents the onset of metamorphosis but not adhesion. Two mechanisms are considered as possibly accounting for induction of metamorphosis: (1) mechanical stimulation by shearing the cilia at the point of contact, and (2) a chemical stimulation of the cell membrane after application of K⁺ or Cs⁺.     

Experimentelle Untersuchungen zur Produktion und Aktivität cellulolytischer Enzyme bei höheren Pilzen aus dem Meer- und Brackwasser

Twenty isolations of marine higher fungi were examined in regard to their cellulolytic capabilities. Application of the viscosimetric method produced detailed information on the cellulolytic activities of marine fungi. However, only the C _x -component of the total cellulase-complex could be estimated by this method. The most active species were Dendryphiella salina, Chaetomium ramipilosum, Asteromyces cruciatus and Humicola alopallonella. Only very slight or no C _x -activity was observed in Cirrenalia macrocephala, Monodictys pelagica and Zalerion maritimum. This finding reveals no correlation between the cellulolytic activity of the fungi in vitro and their frequency on wood-substrates in situ. For example, differences in the intensity of C _x -cellulase production of D. salina are caused by variations in salinity and composition of the nutrient broth, especially by the kind of cellulose added for enzyme induction and by the addition or absence of glucose. Most of the C _x -cellulase produced is present in the cell-free culture-filtrate. Only a small quantity is absorbed by the cellulose particles or the fungal mycelia. Parallel to the mycelial growth, and accompanied by a shift in pH, the C _x -cellulase-activity rises continuously, attaining a maximum after several weeks. During further cultivation, the maximum remains more or less constant for a long period. Tests using different methods, e.g. cellulose-powder-agarplates, proved unsuitable because of spreading hyphal growth, dark pigmentation, heavy sexual or asexual sporulation and relatively low cellulase production during short culture periods.     

Toxizität und anreicherung von blei bei der miesmuschel Mytilus edulis im laborexperiment

In a laboratory experiment, conducted over 130 days, three batches of a total of 100 common mussels, Mytilus edulis, were maintained in media containing different lead concentrations. Two vessels served as controls. There was no acute injury to the mussels; but, over an extended period of time, a marked increase in mortality occurred which was related to the lead concentration in the medium. The median lethal time (LT₅₀) was computed to be 218 days for the control, 150 days with 0.5 mg Pb/l in the medium, 129 days with 1 mg/l, and 105 days with 5 mg/l. Quantitative analyses of the soft parts of M. edulis by flameless atomic-absorption-spectrophotometry revealed a distinct accumulation of lead. From a natural lead content of 8.4 μg Pb/g dry weight, the lead concentration increased to 12,840 μg/g at 0.5 mg/l, to 20,770 μg/g at 1 mg/l and to 39,830 μg/g at 5 mg/l. The ratio of the concentration of lead in the soft parts of M. edulis to the concentration in the medium remained in the same order of magnitude both under laboratory conditions using high lead concentrations and under in situ lead levels. Over a period of 130 days, lead uptake expressed as percentage of lead offered was 10.9% at 0.5 mg/l, 9.5% at 1 mg/l, and 3.4% at 5 mg/l, respectively.     

Der einfluß der temperatur auf oocytenentwicklung und eiablage bei dem interstitiellen archiannelidenTrilobodrilus axi

The interstitial archiannelidTrilobodrilus axi Westheide 1967 inhabits sandy beaches of the Island of Sylt (North Sea). Spawning occurs from May to July, approximately. Development of oocytes and oviposition occur as soon as the water temperature has risen above 5 °C. In rearing experiments, the influence of temperature on maturation and release of gametes was studied in the female. Animals were collected in winter and reared at temperatures between 3° and 15°C. Within this range, development of oocytes and shedding of eggs were accelerated progressively with increasing test temperatures. Successful reproduction occurred only at temperatures above a critical level (between 3° and 6 °C). It was possible to shift the time of spawning by several months under experimental conditions; this suggests that, in the field, spawning is mainly controlled by temperature. The results indicate thatTrilobodrilus axi is probably a boreo-mediterranean species.