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ABSTRACT: Marine biofilms were established on glass beads with or without deliberate pre-exposure to LAS (20 μg/L) in Spain (Cadiz) and Sweden (Kristineberg). The ability of each community to mineralize LAS (100 μg/L) was then assessed in biometers at four experimental temperatures (between 6 and 21°C). Genetic diversity and biomass of the biofilms were assessed by genetic fingerprinting (DGGE) and direct bacterial counts. With biofilms from Sweden, where LAS was not detected in seawater (n = 3), deliberate pre-exposure to LAS resulted in lower genetic diversity and higher mineralization rate constant; however, with biofilms from Spain, where 6.4 ± 3.9 μgLAS/L (n = 3) was measured during the colonization, pre-exposure did not affect the bacterial community. Bacterial acclimation therefore appeared to have been induced at environmental concentrations < 6 μgLAS/L. Environmental pre-exposure was not a pre-requisite for featuring the full consortia of LAS degraders in the biometers. The mineralization rate was described using an Arrhenius equation at experimental temperatures within the typical annual range; however, they departed from this model below this range.
Ecotoxicology and Environmental Safety 03/2011; 74(5):1250-6. · 2.29 Impact Factor
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ABSTRACT: An innovative biodegradation test system was developed in order to fill the current gap for cost effective and environmentally relevant tools to assess marine biodegradability. Glass beads were colonized by a biofilm in an open flow-through system of seawater with continuous pre-exposure to Linear Alkylbenzene Sulfonate (LAS) (20 mu g/L). Thereafter, such colonized beads were added as inoculum in different test systems. [C-14]-LAS (5-100 mu g/L) was added and primary and ultimate biodegradation were assessed. The bacterial density collected on the beads (10(9) bact./mL beads) was ca. 3 orders of magnitude higher than the typical seawater content. The LAS mineralization lag phase duration decreased from 55 to <1 days and the mineralization extent increased from 53 to 90% as the colonized beads volume increased from 10 to 275 mL This is the first demonstration of marine bacteria's ability to mineralize LAS. On the opposite, less than 13% LAS was mineralized in seawater only. The colonized beads possibly enhanced the probability to encounter the full degraders' consortium in a low volume of seawater (100 ml.). (C) 2009 Elsevier Ltd. All rights reserved.
Environment International. 01/2009; 35(6):885-892.
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ABSTRACT: Concentrations of the essential trace metals copper and zinc were measured in the pyloric caeca of female Coscinasterias muricata sampled from Port Phillip Bay, Victoria, Australia at monthly intervals for 15 months. Results indicate that the concentrations of these metals appear to be regulated by the reproductive cycle. Peaks in zinc concentration occurred simultaneously with peaks in progesterone concentration in the pyloric caeca. These findings suggest that zinc plays a role in gametogenesis and ovarian development. Fluctuations in pyloric caeca copper concentration appear inversely related to the pyloric caecal index and associated with oocyte diameter, indicative of a role for this metal in oogenesis. The levels of cytosolic heat stable low molecular mass (LMM) proteins were examined throughout the sampling period. Heat stable LMM proteins (metallothionein-like) of 12 kDa and 7.5 kDa (apparent molecular mass) and the concentrations of copper appear to be related; although the exact nature of these proteins remains unknown. No such relationship was observed between the levels of heat stable LMM proteins and zinc.
Comparative Biochemistry and Physiology Part C Toxicology & Pharmacology 05/2007; 145(3):449-56. · 2.62 Impact Factor
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ABSTRACT: Levels of cytochrome P450 enzymes were measured in pyloric caeca microsomes of the asteroid Coscinasterias muricata following exposure to sediment with nominal concentrations of 0, 0.1 or 2 ml crude oil kg(-1) (dry weight) and subsequent depuration. No significant differences were observed in total cytochrome P450 levels or cytochrome P418 levels following the exposure period. However after five days of depuration, levels of total P450 in the pyloric caeca of C. muricata exposed to the highest oiled sediment concentration were significantly lower than in specimens exposed to the other treatments. Cytochrome P418 levels were inversely related to total P450 levels following exposure and subsequent depuration. Preliminary results show that levels of CYP1A-like immunopositive protein (CYP1A-like IPP) in exposed asteroids exhibited a concentration response relationship following the exposure period. Variations in CYP1A-like IPP levels observed during the depuration period may be influenced by the sublethal toxicity of hydrocarbons within the crude oil.
Chemosphere 01/2007; 65(10):1869-77. · 3.21 Impact Factor
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ABSTRACT: Levels of cytochrome P450 enzymes were measured in pyloric caeca microsomes of the asteroid Coscinasterias muricata following exposure to sediment with nominal concentrations of 0, 0.1 or 2 ml crude oil kg−1 (dry weight) and subsequent depuration. No significant differences were observed in total cytochrome P450 levels or cytochrome P418 levels following the exposure period. However after five days of depuration, levels of total P450 in the pyloric caeca of C. muricata exposed to the highest oiled sediment concentration were significantly lower than in specimens exposed to the other treatments. Cytochrome P418 levels were inversely related to total P450 levels following exposure and subsequent depuration. Preliminary results show that levels of CYP1A-like immunopositive protein (CYP1A-like IPP) in exposed asteroids exhibited a concentration response relationship following the exposure period. Variations in CYP1A-like IPP levels observed during the depuration period may be influenced by the sublethal toxicity of hydrocarbons within the crude oil.
Chemosphere.
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ABSTRACT: Marine biofilms were established on glass beads with or without deliberate pre-exposure to LAS (20 μg/L) in Spain (Cadiz) and Sweden (Kristineberg). The ability of each community to mineralize LAS (100 μg/L) was then assessed in biometers at four experimental temperatures (between 6 and 21 °C). Genetic diversity and biomass of the biofilms were assessed by genetic fingerprinting (DGGE) and direct bacterial counts. With biofilms from Sweden, where LAS was not detected in seawater (n=3), deliberate pre-exposure to LAS resulted in lower genetic diversity and higher mineralization rate constant; however, with biofilms from Spain, where 6.4±3.9 μgLAS/L (n=3) was measured during the colonization, pre-exposure did not affect the bacterial community. Bacterial acclimation therefore appeared to have been induced at environmental concentrations <6 μgLAS/L. Environmental pre-exposure was not a pre-requisite for featuring the full consortia of LAS degraders in the biometers. The mineralization rate was described using an Arrhenius equation at experimental temperatures within the typical annual range; however, they departed from this model below this range.
Ecotoxicology and Environmental Safety.
