Size-associated Variation and Factors Affecting the Morphology of Brown Bodies in Glycera tridactyla (Polychaeta:Glyceridae)

Size-associated variations in brown body morphology (size and shape) were studied from the individuals of Glycera tridactyla. Variables related to size, length (BL) and width (BW) of the brown bodies were measured. On the basis of these measurements, other variables such as the surface area (SA), volume (V), surface area/volume ratio (SA/V) and elongation degree (ED) were calculated. Brown body shape was quantified by the elongation degree. The immature brown bodies were significantly smaller than the mature bodies, and therefore the smaller bodies had a higher SA/V. Results obtained from the regression analysis showed that there was a significant relationship between all the variables with the exception of SA/V:BW for the immature bodies and ED: BL for both groups of the bodies. The body size (proboscis length) of the worm and the sampling time (months) were the affecting factors on size and shape of the brown body. Brown bodies tend to be elongated as the proboscis length increased. The variation in size and/or shape of the brown bodies could refer to an adaptation to the movement along the coelomic fluid

DNA damage in different Eisenia andrei coelomocytes sub-populations after in vitro exposure to hydrogen peroxide

Earthworms play an essential role in providing soil fertility and may represent an important soil contamination bio-indicator. They are able to ingest soil particles, adsorb substances throughout the intestinal epithelium into the coelomic cavity, where chemicals can come in direct contact with coelomic fluid. Earthworm coelomic fluid shelters leucocytes (coelomocytes) that differ significantly both structurally and functionally. Cellular variability could lead to different susceptibility towards contaminants possibly present in soil ecosystem. In order to define population specific dose response to chemicals and to identify a homogeneous cell population to be used as a relevant biomarker, we investigated different coelomocytes subpopulation, obtained by Percoll density gradient centrifugation (5–35 %), exposed ex vivo to H2O2 in the range of concentration 15–120 µM. DNA damage levels were assessed by the comet assay on unseparated coelomocytes and on three enriched cellular fractions (light, medium and heavy density subpopulations). All tested samples showed a dose–response genotoxic effect following H2O2 exposure. Moreover, light density sub-population appeared more susceptible to oxidative insult highlighted by a significant increase in DNA damage indexes at lower concentrations of H2O2. Present data suggested that in these experimental condition coelomocytes light fraction may represent a more sensitive biomarker of genotoxic insult