Über den einfluß des hydrostatischen druckes auf die ultrastrukturen von zellen und geweben. IV. Der effekt der temperatur auf die druckresistenz der membran-, filament- und mikrotubulisysteme verschiedener gewebe mariner muscheln und Branchiostoma lanceolatum

Temperature-pressure experiments have been carried out on gill epithelium of Modiolus modiolus and Mytilus edulis (Baltic and North Seas), as well as on the skin, pharynx, and trunk muscles of Branchiostoma lanceolatum (Pallas), employing the technique of pressure fixation. Temperatures of 0°, 5° and 15°C have been combined with pressures up to 800 atm. Low temperature (0°C) intensifies disintegration of ultrastructures by pressure in comparison to 5°C. The highest degree of structural disorganization can be observed at 600 atm and 0°C. Increased temperature (15°C) increases pressure resistance, but the structural difference is more quantitative than qualitative. In pressure experiments, temperature probably affects cell organelles at the molecular level.     

Die Zellwand mariner Phanerogamen

When leaf pieces of marine phanerogams (Zostera, Posidonia, Cymodocea, Thallassia, etc.) are exposed to air by hanging them up, they continue to loose weight constantly until they are completely dry; transpiration proceeds without limitation. The leaves shirnk to about 1/5 or 1/6 of their original volume. If the leaves are transferred back into water, their weight increases within a few minutes through rapid water absorption, and may even exceed the initial value. This rapid absorption of water is attributed to the cell walls, which were folded by cohesion tension in the dried state and unfolded through water absorption, thus enlarging the cell lumina and taking up water. Rate of water absorption decreases after bioling the leaves, after repeated drying and subsequent water uptake, and after ageing (about 1 year). Dried leaves of terrestrial plants also increase in weight when immersed in water, however, absorption proceeds 200 to 500 times slower than by marine phanerogams. On the other hand, dried freshwater plants absorb water just as quickly as dried marine plants; but the absorption of water amounts to only a small percent of their initial weight. These facts demonstrate that in this respect marine flowering plants hold a special place. In comparison to the mesophyll cells the very small epidermis cells have a thick cell wall especially on their outside. This wall can be stained darkly with ruthenium-red and, therefore, could possibly consist of pectic substances. When transferred from salt water into freshwater, the leaves absorb water in a matter of seconds; the epidermis walls swell and become rigid; the weight capacity of the leaves doubles (Posidonia) within 1 min. The epidermis cell walls, which swell easily, are responsible for the fact that the cells of many marine algae normally do not plasmolise. On their outside, the epidermis walls are covered with an extremely thin cuticle which can be isolated easily by applying chromic acid. Under the light microscope different species exhibit specific cuticle structures. Under the electron microscope a network of perforations can be seen.     

Einfluß von 2,4-dinitrophenol auf die atmung und die Konzentration einiger metabolite bei embryonen des herings Clupea harengus

In rearing experiments with herring eggs (temperature=14.0°±0.1°C; salinity=15‰), oxygen consumption under normal conditions and after addition of 2,4-DNP (concentration=0.1 mM/l; pH=8.1) was measured over the period of embryonic development by means of the Wabburg-technique. Additionally, the concentration of low molecular sugars, polysaccharides, free amino-acids, and adenosintriphosphate (ATP) was determined. The oxygen consumption increases during embryonic development; this increase is not linear. Periods of high intensity of oxygen consumption are followed by others with only slight increase. Immediately before hatching, the respiration curve distincly declines (Fig. 1). Under the influence of 2,4-DNP (dinitrophenol), the embryos increase their respiration intensity after a short period of incubation. The maximum rise in percentage over the normal values reaches up to 400% at the beginning of gastrulation, falls to 50% even before the locking of the blastopore, and decreases slightly to about 30% until hatching. The immense decline in the percentage increase in respiration following the addition of 2,4-DNP at the end of the first day of development is caused by the rapid increase in normal respiration. After poisoning with DNP at different stages of development, the uncoupled respiration curves are normally almost equal. This holds both for the temporal position of the respiration maxima (about 12 to 24 h after poisoning), and for the absolute amounts of the increased respiration over the normal values (5 to 7 μl/h/100 embryos). Excluded from these regularly repeated findings are two stages of development: (1) the stage of epiboly after exceeding the yolk equator until shortly before locking of the blastopore (26 to 32 h after fertilization at 14°C); (2) the period at the end of the 4th day of development when the eyes become pigmented (100 to 120 h after fertilization). These two stages are characterized by the fact that, at the moment of poisoning, the normal respiration shows retarded activity. On the other hand, these two stages are well able to undergo periods of development in which long-living embryonic deformations can occur after uncoupling of respiration with 2,4-DNP. The content in low molecular sugars and polysaccharides decreases slightly in the course of embryonic development and, following the addition of 2,4-DNP, decreases considerably during the first 24 h. After 48 h, accelerated decomposition of carbohydrates continues. Under the influence of 2,4-DNP, the embryos metabolize more carbohydrates in 1 day than during the whole normal development period. The changeover of the metabolism to increased decomposition of carbohydrates can be explained as a dislocation of the energetic sources from the respiration chain to glycolytic phosphorylation. In accordance with these facts, the concentration of free amino-acids, almost equal during normal embryonic development, remains unchanged under the influence of 2,4-DNP.     

Niedere pilze als testorganismen für schadstoffe in meer- und brackwasser die wirkung von schwermetallverbindungen und phenol auf Thraustochytrium striatum

Three test-series were applied, which differed in regard to the basal medium (natural or artificial sea water, salinity level, addition of detergent); the culture conditions (primary cultures, subcultures, back-inoculations into basal medium without toxic metals); the criterion employed (zoospore activity, sporangia development, or dry weight of Thraustochytrium striatum Schneider). The temperature applied was 18° to 20°C. The sea water-pollen-method (MWP) proved to be the most suitable: it is simple and more sensitive than the other tests; subcultures and back-inoculations are possible without much additional work; conditions simulate nature; first results are available after 3 to 4 days. The SMS-method (enriched natural sea water of different salinities) provides additional information on salinity effects. Nine substances have been tested: (CH₃COO)₃Hg, HgCl₂, CdCl₂·H₂O, ZnSO₄ ·7H₂O, NiSO₄·7H₂O, CuSO₄·5H₂O, CoCl₂·6H₂O, MnCl₂ ·4H₂O, and phenol. In regard to their toxicity these substances can be divided into 2 groups: Hg- and Cd-salts inhibit development down to greater dilutions than the remainder; Zn and Ni seem to yield intermediate effects. Salinity modifies the toxic effects of the test substances. In higher salinities, comparable concentrations of test substances reveal stronger inhibitory effects than in lower salinities. Detergents may augment the toxic effects, at least of CuSO₄. The marine lower fungus T. striatum is a useful organism for testing biological consequences of water pollutants.     

Der einfluß der temperatur auf die substrat-affinität der laktat-dehydrogenase aus fischen

If the activity of lactate-dehydrogenase (LDH) at small pyruvate concentrations (e.g. 20μM), as found in vivo, is measured, no temperature-dependence of the reaction-velocity is noted. This finding implies, for a poikilothermic animal (e.g. the fish Rhodeus amarus), that in physiological substrate concentrations, the velocity of enzymatic reaction is temperature-independent. In the LDH of R. amarus acclimated to 10° or 20°C, the enzyme-substrate-affinity, as judged by the Michaelis-constant (K _M), changes inversely with temperature. In contrast to R. amarus, K _M-values of Idus idus have a minimum temperature range identical to the adaptation temperature (AT). The momentary AT (e.g. 10°, 20°C) induces the disposition of an enzyme with greatest substrate-affinity at that temperature, which coincides with the AT. Estimating the activation energy (′E _a=μ) through the Arrhenius-plot, ′E _a for LDH of I. idus amounts to 8.2 kcal/mol in the experimental temperature (ET) range of 5° to 15°C. For ETs above 15°C, a value of ′E _a=12 kcal/mol is found. LDH of I. idus of 20°C, however, shows a smaller value of ′E _a=7.8 kcal/mol beyond ET=15°C; below ET=15°C, ′E _a=10 kcal/mol. If the AT of R. amarus of 10°C is raised to 25°C, and the K _M of LDH for substrate pyruvate and cosubstrate NADH (ET always 25°C) is measured, a dampened oscillation-like curve will be found, depending on time.     

Zum protonephridialsystem mariner gastrotrichen der ordnung macrodasyoidea

The protonephridia of marine gastrotrichs are described from Paradasys subterraneus Remane, Turbanella cornuta Remane, and three other species of the Turbanellidae. Both genera have several terminal organs in serial distribution. Paradasys has 6, Turbanella 4 groups of protonephridia. In Paradasys, 3 protonephridial tubules form a continuous system, while in Turbanella such a system consists of 2 to 4 (5) separate protonephridial tubules.     

Sauerstoffmangelresistenz mariner Bodenvertebraten aus der Westlichen Ostsee

Among the macrobenthos fauna of the Western Baltic Sea, lamellibranchs occurring in poorly oxygenated soft sediments exhibit especially high tolerances to temporary oxygen deficiency. Such tolerance is less well developed in mobile species of various systematic groups than in more or less immobile forms. Commonly, tolerance to oxygen deficiency tends to increase with decreasing temperature. Different qualitative relations between tolerance to oxygen deficiency and temperature may be correlated with the distributional range of the species.     

Untersuchungen über den einfluß von ölverschmutzungen auf meeresalgen. I. Die wirkung von rohölfilmen auf den CO2-gaswechsel außerhalb des wassers

Oil pollution in the sea is generally restricted to thin oil films floating on the water surface. Such oil films tend to coat littoral plants or animals during low tide. The effects of coating with crude oil on the CO₂-uptake of various marine algae has been investigated under conditions of emersion. In emersed algae, CO₂-uptake is more or less depressed, depending on the thickness of the oil film (0.1 to 0.0001 mm) and the type of crude oil (Iran, Libya, Venezuela). On the other hand, water loss during exposure is reduced, so that the oil-covered algae are able to photosynthesize over a longer period than algae without oil cover. After retransfer to oil-free sea water, in most cases photosynthesis rates remain depressed throughout the period of observation. There are two effects which probably interfere with gas exchange: (1) lowering of diffusion rates of photosynthetic gases and of water evaporation by the oil films; (2) toxic effects of crude-oil components.     

Erfassung der strömungsstruktur im substratbereich mariner biotope

In the phytobenthos, exchange of matter is essentially controlled by turbulent water movement. On the other hand, the phytobenthos itself alters properties of the hydrodynamic boundary layer. This paper describes experiments performed and results obtained on water movement in the substrate. Using a special hot-wire microprobe and a computer-compatible measuring device, a preliminary experimental tank model has been set up. The model species is the alga Scytosiphon lomentaria.     

Auswirkungen nanotechnologischer Entwicklungen auf die Umwelt

Background

Nanotechnology is about discovering, developing and using materials consisting in their primary stage at a size within the low nanometer range. These ultrafine particles offer new properties and opportunities. Even if the synthesis of nanoparticles has been discovered not until during the last decades, the exposure of humans to ultrafine particles occurred long before, due to the generation of ultrafine particles in ambient air during combustion processing.

Aim

Within this review, only engineered nanoparticles are considered, because these technical products are associated with many hopes for new applications, while only little information is available about their potential adverse effects. At workpiaces, during manufacturing, in technical applications or in drugs, nanoparticles will always have ‘side effects’ which have carefully to be weighed against their advantages, before they can be released in the environment. Therefore, information about their safety and potential hazards is urgently needed.

Results and Discussion

Along with the technical development of nanoparticles, a public discussion has started, leading to extensive investigations on possible negative ‘side effects’ on human health. Research activities have been strengthened in departments for environmental toxicology, hygiene institutes and other academic facilities to identify hazard and risks during handling and use of these new materials. On the other hand, nanotechnology offers the promise to prematurely identify environmental problems through improved detection and monitoring capabilities, and significantly reduced environmental effects from cleaner manufacturing and synthesis approaches, which results in a reduction or elimination of wastes as well as reduced energy use, and unique remediation solutions as well as pollution strategies.

Conclusions

However, the potential impact of manufactured nanomaterials used in various applications also needs to be evaluated in the context of human health with regard to potential toxicology and routes of exposure, environmental effects, including fate, transport, transformation, bio-availability, and bio-accumulation, and an analysis of product-life cycle.     

Über den einfluß des hydrostatischen druckes auf die ultrastrukturen von zellen und geweben. III. Untersuchungen an filament-und mikrotubulisystemen verschiedener gewebe mariner muscheln und Branchiostoma lanceolatum

Employing the technique of pressure fixation, the effect of high hydrostatic pressure (1 to 800 atm) at 5°C has been investigated on cilia of the gill epithelium in Modiolus modiolus, Mytilus edulis (Baltic and North Seas), and on the skin and muscle cells of Branchiostoma lanceolatum (Pallas). With increasing pressure, the filaments and tubuli are increasingly disorganized to an electron-dense material, which seems to be a conglomeration of the globular structure units. Minimum pressure causing disintegration of filaments and tubules is 300 atm; 600 atm is critical, especially for filaments in skin cells of B. lanceolatum. Whereas the filaments do not show any intermediate stages of damage at any one pressure, microtubules show different stages of disorganization. There seems to be a direct relation between motility and structural organization of cilia. Probably the mechanisms of disintegration of filaments and microtubules are related to the enzymatic activities and the protein-protein-interactions of the subunits. The difference between di-and monomer enzymatic systems in the structures may be important for pressure resistance of the organelles.     

Die Bedeutung der Zeit

Reflecting on time and its nature has a long tradition in such fields as philosophy, economy and the social sciences. In environmental sciences, however, time has not been taken into sufficient consideration to date, although many ecologists are indeed aware of its importance. Because of the importance of time for mankind, nature and the surrounding world, an outline incorporating time is possible and would lead to new insights in environmental sciences. Here, our idea of a balanced or “healthy” ecosystem, or the consequences of our actions such as depletion of the ozon layer, the greenhouse effect or floods are taken into consideration. A reflection on time its a basic requirement for our understanding of environmental science, its tools and our environmental and political actions. A consideration of time in environmental sciences means, among other things, to think of and to act in accordance with time scales and the rhythms of man and nature.     

Die Umsetzung der FFH-Richtlinie in der Agrarlandschaft

The EU Habitats Directive (92/43/EEC) does include provisions for setting up the Natura 2000-network of protected areas based on listed species and habitats, and in addition specific regulations on species protection. Three Quarters of all designated sites (SCI’s) do not only include natural habitat types in a strict sense like forests or water-bodies, but also agricultural land. 18?% of the SCI’s even include between 25 and 50?% agricultural land and 24?% above 50?%. 48 species and three habitat types listed under the Habitats Directive have a clear focus in agriculture. Another eleven habitat types are dependant from a nature-friendly low intensity use or management. A large proportion of these habitats and species are actually in an unfavourable conservation status. The paper analyses the impact of EU nature conservation on agriculture based on the species and habitats falling under the Habitats Directive. On the other hand indirect negative influences of agriculture are discussed, that may have considerable impact on the future development of the conservation status of endangered habitats and species.     

Die Bedeutung der Zeit

The consideration of time in environmental research allows new insights into the fundamentals of environmental research and new pathways for perceiving and answering questions which might arise in environmental research. In order to take this all into account, one must realize that ecological systems have a history and that both the spatial aspects and the chronological expansion of these systems must be taken into consideration. Considering temporalities, rhythms and time scales as well as their interdependencies in environmental research and environmental protection enables us to obtain a better understanding. The significance of relationships and functions in ecological systems can be perceived better as well. The impact of pollutants as well as the outcome of human actions in ecology, and in economics and politics, is consequently mandatory for not only a spatial, but also for the involved temporal scales.     

Über den Einfluß des hydrostatischen Druckes auf die Ultrastrukturen von Zellen und Geweben. II. Untersuchungen an membransystemen von Kiemenepithelien mariner Muscheln und dem Kiemendarm von Branchiostoma lanceolatum

Employing the technique of pressure fixation, high hydrostatic pressure effects on ultrastructures of membrane systems and cell organelles have been investigated, using as material the gill epithelium of marine bivalves and the pharynx epithelium of Branchiostoma lanceolatum (Pallas). Pressure was increased stepwise between 1 and 800 atm. Pressure sensivity of the tissues varies as a function of their structure and function. The degree of disorganization of cell structures increases with increasing pressure. At 300 to 500 atm, the microvilli tend to form small vsicles, which are connected with each other by thin filaments. Especially the basic vesicles become enlarged to oedematous expansions. A variety of membrane disintegrations can be observed on cell organelles, which are connected by membrane-flow. This supports the thesis of the heterogeneity of membranes. Mitochondria reveal destruction of the cristae to an electron-dense material. Membrane lysis can be demonstrated in the endoplasmic reticulum and the plasmalemma of spezialized pharynx cells of B. lanceolatum. The Golgi-apparatus is the only organelle which remains almost unaffected by hystrostatic pressure. There are probably interactions between pressure sensivity of membrane structures and their enzymatic activities.