CONTENT - International Society of Zoological Sciences

S19 ICZ2008 - Abstracts
In vitro methods for the detection of algal neurotoxins to
secure shellfish and fish consumption
Aurélie Ledreux 1,2 , Sophie Krys 2 and Cécile Bernard 1
1 Muséum National d’Histoire Naturelle, USM 505/EA 4105
Ecosystèmes et interactions toxiques, 57 rue Cuvier, CP 39,
75231 Paris cedex 05, France
2 Agence Française de Sécurité Sanitaire des Aliments, Unité
Toxines, Polluants Organiques et Pesticides, 23 avenue du
Général de Gaulle, 94706 Maisons-Alfort cedex, France
The global occurrence of toxic algal blooms has increased in
frequency and intensity over the past 20 years, resulting in an
increase in the number of shellfish production area affected by
phycotoxins (Hallegraeff, 2003).
To keep shellfish and fish consumption secure, the risk
management associated to phycotoxin contamination in shellfish
and fish is based on monitoring of toxins in seafood destined to
human consumption (Yasumoto, 1995). The available chemical
methods, while being efficient for the detection of identified toxins
are inadequate for the detection of emerging toxins or unknown
analogues. As a consequence, detection of algal toxins is still
based on mouse bioassays in spite of their poor sensibility, their
lack of specificity and the ethical issue.
Alternative assays are required which are reliable, sensitive and
able to detect toxic agents depending on the molecular mechanism
by which they affect biological systems. In vitro methods are
attractive since they are inexpensive and allow a rapid screening
of a large number of samples.
The aim of this study was to determine if the specific detection of
three neurotoxins families (saxitoxins, brevetoxins and palytoxin
and analogues), acting on two different cellular targets can be
performed by using a single neuroblastoma cell-line (Neuro-2a).
To that end, pure toxins have been tested in order to evaluate the
sensibility of the Neuro-2a cell based assay. The specificity of the
assay for each type of toxins was achieved by the use of two
antagonists: ouabain and veratridine. The matrix effect was
assessed by testing algal extracts and mussel extracts.
Bioaccumulation of heavy metals in the tissues of two
flatfishes (Platichtys flesus and Solea vulgaris) from the outer
coast and Ría of Vigo, NE Atlantic (Spain)
Lazhar M’Hadhbi 1,2 , Dragos Zaharescu 2 , Tahar Gharred 3 , Antonio
Palanca 2 and Moncef Boumaïza 1
1 Hydrobiology Unit, Enironmental Biomonitoring Laboratory,
Faculty of Sciences, Bizerte, Zarzouna 7021, Tunisia
2 Animal Anatomy Laboratory, Vigo University, 36310 Vigo,
Spain
3 Marine Biotechnological Institute of Monastir,Tunisia
Concentrations of ten heavy metals (Cd, Pb, Hg, Cu, Zn, As, Se,
Ag, Mn, Sn) in liver, muscle and kidney of European flounder
(Platichtys flesus) and the sole (Solea vulgaris) from Ria of Vigo
and its coastal zone (Spain) were measured from April 2006 to
February 2007 and the relationships between fish size (length and
weight), age, gender, season and metal concentrations in the
tissues was investigated.
The average metal concentrations in different organs varied in the
following ranges: Cd (0.01- 2.08), Pb (0.02- 2.91), Hg (0.015- 2.13),
Cu (2.5- 46.71), Zn (12.7- 996.7), As (1.2- 151.9), Se (1.56- 34.02),
Ag (0.01- 5.81), Mn (0.27- 57.26), Sn (0.01 to 5.07) µg g -1 dry
weight. Fish kidney and liver registered highes levels of Cd, Cu, Pb
and Zn, whereas the muscles registred highest Hg concentrations.
Platichtys flesus tended to accumulate more quantities than Solea
vulgaris. A comparison of metals concentration in fishes from both
sites shown higher bioaccumulation in those exemplars from the
Ria of Vigo. This means a tendency of higher pollution levels in the
estuarine environment. Seasonal variability generally indicated
increased levels of metals bioaccumulation during winter, the
period of heavy rains and high flows from the surrounding Vigo
cityscape.
Although, generally, metals levels in the tissues of fish in the area
are not harmful for humans, measures shall be taken to lower
heavy metals inputs into Ria of Vigo.
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Global quantitative analysis of protein phosphorylation status
in liver of fish exposed to the Cyanotoxin Microcystin
Mélodie Malécot 1 , Karim Mezhoud 1 , Danièle Praseuth 2,3 , Arul
Marie 4 , Simone Puiseux-Dao 1 and Marc Edery 1
1 USM 505/EA 4105 Écosystèmes et interactions toxiques,
Département de « Régulations, développement et diversité
moléculaire », Muséum national d’Histoire naturelle, 12 rue Buffon,
F-75231 Paris Cedex 05, France ; 2 INSERM, U 565 and 3 MNHN,
USM 503 Laboratoire des Régulations et dynamique des génomes,
Département de « Régulations, développement et diversité
moléculaire », CNRS, UMR 5153, Acides nucléiques: dynamique,
ciblage et fonctions biologiques, Muséum national d’Histoire
naturelle, 57 rue Cuvier, CP26, F-75231 Paris Cedex 05, France ;
4 Plateforme de spectrométrie de masse et de protéomique,
Département de « Régulations, développement et diversité
moléculaire », Muséum National d’Histoire Naturelle, 63 rue Buffon,
F-75231 Paris Cedex 05, France
Microcystins (MCs) are hepatotoxins inhibiting protein
phosphatases PP1 and PP2A. These peptides produced by some
freshwater cyanobacteria are getting attention due to their acute
toxicity and tumor-promoting activity. To date, the detailed
mechanisms underlying their toxicity are unknown. MC-leucinearginine
(MC-LR) is the most toxic and the most commonly
encountered MC variant in aquatic environment. Toxicological
investigations on the liver of the aquatic model, the medaka fish,
have been performed with differential proteome analyses of MC-
LR-treated (by 2 exposure routes; water or food contamination)
and untreated medaka fish in order to investigate the
mechanisms of establishment of early responses to the toxin.
Cytosolic, membrane and organelle proteins from livers were
resolved by 2D electrophoresis and detected using stains specific
for phosphoproteins and for whole protein content. Overall, more
than 100 spots were found to vary significantly on the proteomic
2D maps or on the phosphoproteomic 2D maps. Of these, 32
proteins could be identified by mass spectrometry. Among them,
phenylalanine hydroxylase, keratin 18 (type I) and grp78 showed
variations in phoshoryl content that could be directly associated
with inhibition of PP activity. The other identified proteins
exhibited variations in their expression level. The identified
proteins appear to be involved in cytoskeleton assembly, cell
signalling, oxidative stress and apoptosis. The reported
methodology should be widely used to a number of tissues and
organisms, thus helping in the search for biomarkers of MC-LR
contamination.
Study of the insecticidal activity of alkaloids of the
hairybroom (Cytisus triflorus L’Hér.) and of the bacterium
Bacillus thuringiensis against the desert locust Schistocerca
gregaria
Hakima Mohand Kaci 1 , Karima Ait-Kaci 1 , Bahia Doumandji-
Mitiche 2 and Fethia Fazouane 1
1 Faculty of Sciences, Department of Biology, University of
Boumerdes, Algeria; 2 El Harrach National Agronomy Institute,
Alger, Algeria
In many regions of Africa and Asia (including Algeria), in addition
to abiotic factors such as climate, food security relies mainly on
crop protection. Crops are under attack from locusts, e.g. the
desert locust S. gregaria. Among existing forms of control, are
those involving entomopathogenous microorganisms, e.g. the
bacterium B. thuringiensis, or acridicide natural products, e.g.
those extracted from the shrub C. triflorus. In the present work, we
compare the effects of B. thuringiensis and alkaloids of C. triflorus
on digestive tract histology of the of adult locusts and on three
physiological parameters: heart rate, respiratory rate and
haemocyte number. The digestive tract anatomy of control and
treated animals appeared identical. Histological examination of the
three parts of the digestive tract (stomodeum, mesenteron and
proctodeum) of locusts treated with alkaloids and by the bacterium
showed that histological changes occurred in the three parts.