Experimental evidence of chemokinesis in newly hatched cod larvae (Gadus morhua L.)

The swimming behaviour of laboratory-reared newly hatched cod larvae (Gadus morhua L.) was observed in a control solution of artificial seawater and in seven solutions, each with a different concentration of arginine (10⁹ to 10^-3 M). The behaviour of 20 larvae was analysed in each of the eight solutions; the individual observation time was 1 min. Individual movements were recorded on video and analyzed using a computer-assisted program. The larvae swam in straight lines (a trajectory), rested, moved and started swimming again. For the parameters analyzed, i.e., number of movements, angle between successive trajectories and straightness index, there was no significant difference between the behaviour of the larvae in the different solutions. However, for the larvae in 10^-5, 10^-4 and 10^-3 M arginine solutions, the analyzed parameters, i.e., time active, frequency of trajectories (number of movements exceeding body length), distance swum min^-1, length of individual trajectories and trajectory velocity, were all significantly lower than for the larvae in the control solution of artificial seawater and for larvae in the solutions of 10^-9, 10^-8, 10^-7 and 10^-6 M arginine. The results show that the mean distance swum by cod larvae min^-1 was two to five times longer in artificial seawater without arginine and in the four lower concentrations of arginine than in the three higher concentrations. Scanning micrographs show that newly hatched (pre-feeding) cod larvae possess olfactory organs. It seems reasonalbe to assume that the observed changes in swimming behaviour are mediated by the olfactory sense and are important in the feeding strategy of cod larvae. We suggest that the observed behaviour increases the probability of the larvae localizing patches of prey organisms and remaining in the patch once they have found it. The results show that chemokinesis is a mechanism by which the spatial distribution of fish larvae will be correlated with their prey.     

Trisomy 12 mosaicism in amniocytes and dysmorphic child despite normal chromosomes in fetal blood sample

Trisomy 12 mosaicism (44 per cent) was detected prenatally in cultured amniocytes. A cordocentesis was performed to confirm the result. Only normal cells were found in the fetal blood sample. The fetus was estimated to be at a low risk of having a chromosomal abnormality and the pregnancy continued. Eight days after birth, a congenital heart defect was detected in the child. Several dysmorphic features were also evident. Further karyotyping of different tissues revealed normal blood and urinary cells but trisomic cells in the placenta (100 per cent) and in skin fibroblasts (25 per cent). The child died at 5 weeks of age. In this case, the fetal blood sample failed to reveal the real chromosome constitution of the fetus.     

Correction to: Identification of structural breaks in the forest product markets: how sensitive are to changes in the Nordic region?

Mitigation and Adaptation Strategies for Global Change - This paper was published on March 2017, Volume 22, Issue 3, 469–483pp, titled “Identification of structural breaks in the forest...     

Application of Poly(styrene-co-divinylbenzene) Macroporous Microparticles as a Catalyst Support in the Enzymatic Synthesis of Biodiesel

Macroporous poly(styrene-co-divinylbenzene) microparticles, with three different structural characteristics, have been synthesized and used as supports in the immobilization of lipase from Burkholderia cepacia. The best immobilization yield was found upon using microparticles with 35 % of divinylbenzene and the immobilized lipase on this type of particles was used as a catalyst to obtain biodiesel from soybean oil and ethanol. From the experimental results of the transesterification reaction, an empirical model quantitatively relating the temperature, the concentration of the enzyme and the transesterification yield was obtained. Statistical analysis of this model indicated that within the range of values of the variables studied (35–47 °C and 231–788 U/mg respectively) only the enzyme concentration exerted a significant influence on the reaction yield. Additionally, the good fit of a Michaelis–Menten-type model to the experimental results suggests that the limiting step of the reaction was the formation of the enzyme-substrate complex.     

Sub-chronic exposure to fluoxetine in juvenile oysters (<Emphasis Type="Italic">Crassostrea gigas</Emphasis>): uptake and biological effects

The bioconcentration potential of fluoxetine (FLX) and its biological effects were investigated in juvenile Pacific oyster exposed for 28 days to environmentally relevant concentrations of FLX (1 ng L^?1, 100 ng L^?1 and up to 10 μg L^?1). FLX bioaccumulated in oyster flesh resulting in 28-day bioconcentration factors greater than 2,000 and 10,000 by referring to wet and dry weights, respectively. Nevertheless, FLX did not induce oyster mortality, delayed gametogenesis, or lead to adverse histopathological alterations. At the two highest concentrations, despite non-optimal trophic conditions, FLX stimulated shell growth but only in a transient manner, suggesting a role of serotonin in the regulation of feeding and metabolism in bivalves. Those high concentrations seemed to drive bell-shaped responses of catalase and glutathione S-transferase activities throughout the exposure period, which may indicate the activation of antioxidant enzyme synthesis and then an enhanced catabolic rate or direct inhibition of those enzymes. However, no clear oxidative stress was detected because no strong differences in thiobarbituric acid-reactive substance (TBARS) content (i.e. lipid peroxidation) were observed between oyster groups, suggesting that cellular defence mechanisms were effective. These results demonstrate the importance of considering additional biomarkers of oxidative stress to obtain a comprehensive overview of the FLX-induced changes in marine bivalves exposed under realistic conditions. Considering the battery of biomarkers used, FLX appears to induce little or no effects on oyster physiology even at a concentration of 10 μg L^?1. These results do not confirm the lowest observed effect concentration (LOEC) values reported by some authors in other mollusc species.     

Debriefing with teachers after the Marmara earthquake: an evaluation study1

The aim of this study was to evaluate the effectiveness of the debriefing meetings conducted after the 1999 earthquakes in Marmara, Turkey. The sample consisted of 265 teachers, 223 of whom attended the debriefing meetings. The personal satisfaction ratings of the teachers who attended the meetings revealed that they found the sessions satisfactory. The results of the comparison between those who reported that they benefited from the meetings and those who felt they did not indicated that the first group had lower scores on all of the psychopathology measures. A comparison between 42 teachers who did not attend the meetings and a randomly chosen group of 45 teachers who did attend revealed that the two groups differed significantly in terms of their post‐traumatic stress symptom scores. The findings of the study suggest that, in general, the teachers' debriefing sessions were satisfactory.