We studied the attachment strength of Dreissena polymorpha on nine artificial substrata in the laboratory. The highest attachment strength (0.46 N) was found on resocart (phenoplast plastic). It was lower on aluminium, acrylic, PVC, rubber and glass (listed in the order of decreasing strength), and the lowest on zinc, Penaten cream coating and copper. Apart from reducing adhesion, copper substratum caused also heavy mortality of the mussels. Further experiments, in which mussels were exposed on resocart surfaces in the presence of the examined materials (thus being influenced only by waterborne substances released by them), revealed that zinc and copper inhibited mussel attachment primarily by means of ions released to the water column. In the case of Penaten coating, the impact of its surface properties upon mussels seemed to be more important than waterborne cues.
FITC conjugate Bioveta, Ivanovice, Czech Republic, used in routine rabies diagnosis, gives a non-specific background fluorescence in brain impression slides. The effect may cause some problems in the proper diagnosis when only a small number of specific inclusion bodies are present. The paper presents an attempt to reduce the non-specific background fluorescence in preparations of brain impressions labelled with Bioveta antirabies conjugate adsorbed with the suspension of normal mouse brain or counterstained with Evans Blue. The background fluorescence has been markedly reduced and the increased number of inclusion bodies were also observed in impresions labelled by Bioveta conjugate with Evans Blue or adsorbed with normal mouse brain tissue in comparison to brain impressions labelled with Bioveta conjugate without these modifications. FA conjugate by diagnostics Pasteur was used as a reference because slides stained with this conjugate have not had any background fluorescence.