Effects of technetium on marine micro-organisms

Eleven bacterial species have been isolated from the upper layer of intertidal sediments collected along the Belgian coast (Coxyde). Three of them (no. 1, 4 and 11) have been chosen for their halophilous character. One species has been identified as Flavobacterium halmephilum, the other two are being investigated. Effects of technetium (99Tc) have been studied on a mixed bacterial population isolated from sediments, as well as on the three halophilic species.At the concentrations utilized in this work (up to 100 microg ml-1), 99Tc has no evident effects on bacterial growth. Uptake of technetium (99Tc and/or 95mTc) has been investigated in the mixed bacterial population, in the three halophilic bacteria (including Flavobacterium halmephilum) and in the benthic ciliate Uronema marinum. It has been found that technetium is taken up by all these micro-organisms. However, the transfer factor (TF) in bacteria may vary considerably (from 0.5 to 200), but the cause of this variability is not known and deserves further study.The ciliate Uronema marinum, which feeds on living marine bacteria, was found to take up 95mTc added to the culture medium. However, the TF in this ciliate is rather low (from 1.4 to 5.5). Because it feeds on bacteria, Uronema marinum is supposed to take up technetium from water (direct contamination) as well as from contaminated bacteria (indirect contamination). Experiments with 95mTc-labeled bacterial cells might be useful, as they could indicate which form of contamination (direct or indirect) is prevailing

Physiological and Behavioural Responses to Noxious Stimuli in the Atlantic Cod (Gadus morhua)

In the present study, our aim was to compare physiological and behavioural responses to different noxious stimuli to those of a standardized innocuous stimulus, to possibly identify aversive responses indicative of injury detection in a commercially important marine teleost fish, the Atlantic cod. Individual fish were administered with a noxious stimulus to the lip under short-term general anaesthesia (MS-222). The noxious treatments included injection of 0.1% or 2% acetic acid, 0.005% or 0.1% capsaicin, or piercing the lip with a commercial fishing hook. Counts of opercular beat rate (OBR) at 10, 30, 60, 90 and 120 min and observations of behaviour at 30 and 90 min post-treatment were compared with pre-treatment values and with control fish injected with physiological saline, an innocuous stimulus. Circulatory levels of physiological stress indicators were determined in all fish at 120 minutes post-treatment. All treatments evoked temporarily increased OBR that returned to pre-treatment levels at 60 minutes (saline, 0.005% capsaicin, hook), 90 minutes (0.1% acetic acid, 0.1% capsaicin), or 120 minutes (2% acetic acid), but with no significant differences from the control group at any time point. Fish treated with 0.1% and 2% acetic acid and 0.1% capsaicin displayed increased hovering close to the bottom of the aquaria and fish given 2% acetic acid and 0.1% capsaicin also displayed a reduced use of shelter. The only effect seen in hooked fish was brief episodes of lateral head shaking which were not seen pre-treatment or in the other groups, possibly reflecting a resiliency to tissue damage in the mouth area related to the tough nature of the Atlantic cod diet. There were no differences between groups in circulatory stress indicators two hours after treatment. This study provides novel data on behavioural indicators that could be used to assess potentially aversive events in Atlantic cod

Diagnostic value of a synthetic peptide derived from Echinococcus granulosus recombinant protein.

A specific monoclonal antibody (MAb; EG 02 154/12) directed against a protein epitope of Echinococcus granulosus antigen 5 was used to screen a cDNA library constructed from E. granulosus protoscoleces RNA. One clone designated Eg14 was selected and shown to code for an amino acid sequence partially homologous to that of the clone Eg6 previously identified with the same MAb. Hydrophobic cluster analysis showed that both recombinant antigens may adopt a similar alpha-helical organization and share a common conformational epitope. A synthetic peptide (89-122) mimicking the conformational site of Eg6 and Eg14 was constructed and demonstrated to be able to inhibit binding of the MAb and human hydatid sera to the Eg6 fusion protein (FP6) or to native hydatid antigens. To assess the diagnostic value of the peptide 89-122, we tested sera from patients infected with different parasites for their antibody reactivity with this peptide in ELISA. A high binding sensitivity and specificity of IgG-A-M antibodies were obtained with E. granulosus-infected patient sera. Moreover, the peptide 89-122 was found to be specifically recognized by IgE antibodies from patients with hydatid disease. These results indicate the particular interest of this synthetic peptide as a standardized antigen in diagnosis and treatment surveillance of hydatidosis