Biochemical, metabolic, and behavioural responses and recovery of Daphnia magna after exposure to an organophosphate

2010 ◽  
Vol 73 (3) ◽  
pp. 353-359 ◽  
Author(s):  
Sabine Duquesne ◽  
Eberhard Küster
Author(s):  
Valeria Di Nica ◽  
Cristiana Rizzi ◽  
Antonio Finizio ◽  
Lorenzo Ferraro ◽  
Sara Villa

In this study, the behaviour of Daphnia magna was studied under equipotent and sub-lethal concentrations of two pesticides congeners: chlorpyrifos (CPF; 5 ng L-1 to 50 ng L-1) and chlorpyrifos-methyl (CPF-m; 30 ng L-1 to 300 ng L-1) with aims to assess and compare the behavioural swimming responses (BSRs) of the cladocerans elicited by both compounds at different concentrations and exposure times. A video tracking analysis after 24 h and 48 h of exposure allowed us to evaluate different behavioural responses (distance moved, average velocity, active time, and average acceleration). The results indicate that BSRs are sensitive indicators of sub-lethal stress. Highly concentration- and time-response changes for both compounds were observed during the experiments. In particular, in the first 24 h of exposure, both compounds elicited a similar decreasing trend in swimming behaviour, in which CPF induced the highest decline. Further, hypoactivity was associated with the narcotic effects of both compounds. Conversely, after 48 h of exposure, we observed an increasing tendency in the swimming parameters, particularly at the highest tested concentrations. However, the compounds did not exhibit the same trend. Rather, CPF-m induced high variations from the control groups. This reversal trend could be due to the activation of compensatory mechanisms, such as feeding, searching, or avoidance behaviours. These results suggest that BSRs are measurable active responses of organisms, which are controlled by time.


Author(s):  
Patricia L. Jansma

The presence of the membrane bound vesicles or blebs on the intestinal epithelial cells has been demonstrated in a variety of vertebrates such as chicks, piglets, hamsters, and humans. The only invertebrates shown to have these microvillar blebs are two species of f1ies. While investigating the digestive processes of the freshwater microcrustacean, Daphnia magna, the presence of these microvillar blebs was noticed.Daphnia magna fed in a suspension of axenically grown green alga, Chlamydomonas reinhardii for one hour were narcotized with CO2 saturated water. The intestinal tracts were excised in 2% glutaraldehyde in 0.2 M cacodyl ate buffer and then placed in fresh 2% glutaraldehyde for one hour. After rinsing in 0.1 M cacodylate buffer, the sample was postfixed in 2% OsO4, dehydrated with a graded ethanol series, infiltrated and embedded with Epon-Araldite. Thin sections were stained with uranyl acetate and Reynolds lead citrate before viewing with the Philips EM 200.


Author(s):  
E. R. Macagno ◽  
C. Levinthal

The optic ganglion of Daphnia Magna, a small crustacean that reproduces parthenogenetically contains about three hundred neurons: 110 neurons in the Lamina or anterior region and about 190 neurons in the Medulla or posterior region. The ganglion lies in the midplane of the organism and shows a high degree of left-right symmetry in its structures. The Lamina neurons form the first projection of the visual output from 176 retinula cells in the compound eye. In order to answer questions about structural invariance under constant genetic background, we have begun to reconstruct in detail the morphology and synaptic connectivity of various neurons in this ganglion from electron micrographs of serial sections (1). The ganglion is sectioned in a dorso-ventra1 direction so as to minimize the cross-sectional area photographed in each section. This area is about 60 μm x 120 μm, and hence most of the ganglion fit in a single 70 mm micrograph at the lowest magnification (685x) available on our Zeiss EM9-S.


1981 ◽  
Vol 12 (1) ◽  
pp. 63-79
Author(s):  
R. Cabridenc ◽  
Bui Thi ◽  
H. Lepailleur
Keyword(s):  

2002 ◽  
Vol 38 (4) ◽  
pp. 11
Author(s):  
M. G. Mardarevich ◽  
D. I. Gudkov ◽  
L. S. Kipnis ◽  
V. V. Belyaev

2002 ◽  
Vol 38 (1) ◽  
pp. 11
Author(s):  
A. A. Ratushnyak ◽  
M. G. Andreyeva ◽  
V. Z. Latypova ◽  
L. G. Garipova

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