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Fouling-release coatings prevent fouling of ships' hulls through hydrodynamic forces generated as the ship moves through the water. The effectiveness of such coatings may be evaluated by measuring the adhesion strength of settled organisms, e.g. barnacles. The influence of desiccation of the barnacle adhesive on such measurements was investigated. Shear forces required to remove barnacles of the genus Balanus increased during the course of desiccation up to the point when the barnacles suddenly self-detached. The increase was thought to be due to the rising cohesive strength of the adhesive. Growing tensile forces within the weakly cross-linked adhesive, however, are suggested to have led to self-detachment. The shear forces required to remove barnacles of the genus Elminius were generally low and did not differ significantly during the course of desiccation. The different results may be attributed to specific base morphologies. It was concluded that measuring the adhesion strength of members of the Balanidae on non-stick surfaces in air could produce flawed results due to the influence of desiccation of the barnacle adhesive. The investigations have also provided new insights into the characteristics of barnacle adhesive. 相似文献
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Investigations during several cruises (1979–1981) showed that Atlantic cod with pseudobranchial tumours occurred in all areas investigated. Statistical analysis of data revealed that there was a marked prevalence of the condition in the centre of the German Bight, whereas a lower incidence of the condition was observed on the Dogger Bank, off the Dutch coast and in the western Baltic Sea. The higher prevalence of pseudobranchial tumours in the German Bight coincides with a dense population of cod and impacts of pollution. 相似文献
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Rothmeier Louisa Marie Sahm René Watermann Burkard Grabow Karsten Koester Meike Cichy Anna Martens Andreas 《Hydrobiologia》2021,848(10):2569-2578
Hydrobiologia - The introduction of non-indigenous organisms in new areas in the context of host-parasite interactions is still poorly understood. This study aimed at a parasitological and... 相似文献
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Watermann I Gerspach J Lehne M Seufert J Schneider B Pfizenmaier K Wajant H 《Cell death and differentiation》2007,14(4):765-774
To achieve tumor cell-restricted activation of CD95, we developed a CD95L fusion protein format, in which CD95L activity is only unmasked upon antibody-mediated binding to tumor cells and subsequent processing by tumor-associated proteases, such as matrix metalloproteases (MMPs) and urokinase plasminogen activator (uPA). On target-negative, but MMP- and uPA-expressing HT1080 tumor cells, the CD95L prodrugs were virtually inactive. On target antigen-expressing HT1080 cells, however, the CD95L prodrugs showed an apoptotic activity comparable to soluble CD95L artificially activated by crosslinking. CD95 activation by the CD95L prodrugs was preceded by prodrug processing. Apoptosis was blocked by inhibitors of MMPs or uPA and by neutralizing antibodies recognizing the targeted cell surface antigen or the CD95L moiety of the prodrugs. In a xenotransplantation tumor model, local application of the prodrug reduced the growth of target antigen-expressing, but not antigen-negative tumor cells, verifying targeted CD95L prodrug activation in vivo. 相似文献
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TBT effects on the female genital system of Littorina littorea: a possible indicator of tributyltin pollution 总被引:4,自引:4,他引:0
Barbara Bauer Pio Fioroni Imke Ide Stefanie Liebe Jörg Oehlmann Eberhard Stroben Burkard Watermann 《Hydrobiologia》1995,309(1-3):15-27
Specimens of the prosobranch Littorina littorea (L., 1758) collected along the East Frisian North Sea coast in summer 1993 exhibited alterations of the pallial oviduct termed
as intersex in response to tributyltin (TBT) pollution. The range of TBT body burden was between 150.9 and 1289.5 μg as Sn
kg−1 (dry wt.). Five stages of intersex development (0–4) could be distinguished and are documented with scanning electron micrographs.
In stages 2–4, which can be found in the direct vicinity of harbours and marinas, the morphological malformations of the oviduct
inhibit successful copulation and capsule formation, resulting in sterilization.
The intersex index (ISI, calculated as the average intersex stage of a population) and the average prostate length of females
were used as parameters for the determination of intersex intensities in the populations. Both indices show significant and
positive correlations to the TBT body burden of L. littorea and are promising parameters for TBT biomonitoring. A comparison of TBT bioconcentration factors with populations from England
and France indicates that the threshold concentration for intersex development is in the range of 15 ng TBT as Sn/l.
Morphometric analyses of the midgut gland revealed no significant differences between sampling stations. In the ovary a retardation
and blockage of maturation (atresia) was observed in populations close to harbours. Lytic processes in ovary follicles were
observed not only at TBT exposed sites but also at reference stations. 相似文献
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Fouling-release coatings prevent fouling of ships' hulls through hydrodynamic forces generated as the ship moves through the water. The effectiveness of such coatings may be evaluated by measuring the adhesion strength of settled organisms, e.g. barnacles. The influence of desiccation of the barnacle adhesive on such measurements was investigated. Shear forces required to remove barnacles of the genus Balanus increased during the course of desiccation up to the point when the barnacles suddenly self-detached. The increase was thought to be due to the rising cohesive strength of the adhesive. Growing tensile forces within the weakly cross-linked adhesive, however, are suggested to have led to self-detachment. The shear forces required to remove barnacles of the genus Elminius were generally low and did not differ significantly during the course of desiccation. The different results may be attributed to specific base morphologies. It was concluded that measuring the adhesion strength of members of the Balanidae on non-stick surfaces in air could produce flawed results due to the influence of desiccation of the barnacle adhesive. The investigations have also provided new insights into the characteristics of barnacle adhesive. 相似文献
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Atlantic cod bearing pseudobranchial tumours were investigated from both North Sea and Baltic Sea areas. Light and electron microscopic studies revealed a tumorous structure previously described in cod from Atlantic and Pacific waters. Additionally, cysts, multinucleated cells and early stages of mitosis are described. These findings support the hypothesis that pseudobranchial tumours are instigated by a protozoan infection causing xenotumours associated with the pseudobranch organ. The cells contained in these lesions showed similarities to amoebae. 相似文献
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Burkard Watermann Anja Thomsen Heike Kolodzey Bernd Daehne Maike Meemken Ute Pijanowska Gert Liebezeit 《Helgoland Marine Research》2008,62(2):167-175
During a combined research project at several stations along the Lower Saxony coast (German North Sea) antifouling biocides
were analysed in water, sediment and biota. Pathological alterations in blue mussel, Pacific oyster and periwinkle found in
the harbour of Norderney and a reference station are presented here and discussed on the background of chemical analyses.
The molluscan species from the reference station Borkum East flat did not show any pathological effects in central organs,
except those provoked by an infestation in the gastro-intestinal tract by the copepod Mytilicola
intestinalis and trematode larvae. In most animals, the metacercaria were found in the interstitial tissue without any inflammatory reaction.
In a minor number of specimens, an inflammatory reaction in the mucosa and sub-mucosa of the intestine occurred in association
with Mytilicola infestation. These reactions may be evoked through mechanical irritation of the gut epithelium, metabolic products of the
parasites or invading bacteria. In contrast to the observed pathological changes of mussels, oysters and periwinkles in Norderney
harbour were not found to be associated with parasitic infestation. The most prominent pathological alterations were observed
in the digestive system and in the gonad. In the gastro-intestinal tract inflammatory reactions, atrophy and necrosis of tubules
in the mid gut gland were most pronounced in spring at the beginning of the pleasure boat season in the Pacific oyster and
to a minor degree in the blue mussel and the periwinkle. The latter displayed additional inflammatory and necrotic processes
in the gills. Especially in the gonad, an elevated resorption rate of gametes was present in the Pacific oyster and in the
periwinkle. In addition, impact of organotin compounds was reflected in an intersex index of up to 1.4 in Littorina littorea in coincidence with masculinization of the reproductive organs. 相似文献
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