Moncef Boumaiza

Effects of deltamethrin (pyrethroid insecticide) on growth, reproduction, embryonic development and sex differentiation in two strains of Daphnia magna (Crustacea, Cladocera)

Acute and different chronic ecotoxic effects of deltamethrin have been investigated on two strains (coming from two different laboratories) of Daphnia magna. The effective concentrations immobilizing 50% of daphnids (EC50s) after 24 h and 48 h were 9.40 and 0.32 μg L(-1), 8.86 and 0.63 μg L(-1) for first strain (strain 1) and second strain (strain 2), respectively. Thus, there was an increase of deltamethrin ecotoxicity with time of exposure as confirmed by chronic studies. After 21 days of exposure to deltamethrin, daphnids have showed significant effects on survival at deltamethrin concentrations of 0.16 μg L(-1) and 0.31 μg L(-1) for strains 1 and 2, respectively. Eleven other endpoints were examined: body length, population growth rate and various reproductive parameters (days to first brood, number of broods, number of cumulative molts and number of neonates), embryotoxicity and appearance of males. IC10 values related to the number of juveniles per live adult were 11 and 46 ng L(-1) for strains 1 and 2, respectively. Furthermore, an increase in embryo deformities was observed at the highest concentrations tested for both strains. Following deltamethrin exposure, undeveloped second antennae, curved or unextended shell spines, and curved post abdomen spines were observed in live neonates. The production of male juveniles was only registered with strain 1 at 0.16 μg L(-1). Results suggest that deltamethrin could act as an endocrine disruptor in D. magna as it interferes with sex determination and development abnormality but there is a difference in sensitivity between the two tested strains.

Is acetylcholinesterase a biomarker of susceptibility in Daphnia magna (Crustacea, Cladocera) after deltamethrin exposure?

In the present study, we explored the possibility of using the acetylcholinesterase (AChE) as a biomarker after deltamethrin (pyrethroid insecticide) exposure with three strains of the cladoceran Daphnia magna. Four calculated time-weighted deltamethrin concentrations (20.1, 40.3, 80.6 and 161.3 ng L(-1)) were compared against control acetylcholinesterase activity. Our results showed that after 48 h of deltamethrin exposure, all treatments induced a significant decrease of AChE activities whatever the three considered strains. However, diverse responses were registered in terms of lowest observed effect concentrations (LOEC: 80.6 ng L(-1) for strain 1 and 20.1 ng L(-1) for strains 2 and 3) revealing differences in sensitivity among the three tested strains of D. magna. Our results suggest that after deltamethrin exposure, the AChE activity responses can be also used as a biomarker of susceptibility (i.e., variation of strain specific response). Moreover, our results show that strain 1 is the less sensitive in terms of IC50-48 h of AChE, whereas it became the most sensitive when considering the EC50-48 h estimated in the standard ecotoxicity test.

Investigation of differences in sensitivity between 3 strains of Daphnia magna (crustacean Cladocera) exposed to malathion (organophosphorous pesticide)

Acute and chronic ecotoxic effects of organophosphorous insecticide malathion (Fyfanon 50 EC 500 g L−1) were investigated on three strains of Daphnia magna. The nominal effective concentrations immobilizing 50% (EC50) of Daphnia after 24 and 48 h were 0.53 and 0.36 μg L−1, 0.70 and 0.44 μg L−1, and 0.75 and 0.46 μg L−1 for the strains 1, 2, and 3 respectively. There was an increase in malathion ecotoxicity with time of exposure as confirmed by chronic studies. In fact, after 21 days of exposure, significant effects on survival (lowest observed effect concentration or LOECs) were recorded at malathion concentrations of 22, 220 and 230 ng L−1 for strains 1, 2 and 3 respectively. Other endpoints were also examined, including reproduction (with different parameters), body length and embryo toxicity. ICs10 and ICs20 were calculated for these different parameters. ICs10 ranged from 4.7 to more than 220 ng L−1 for the three tested strains. The most sensitive parameter was the number of neonates per adult (ICs10 = 4.7 and 10.8 ng L−1 for strains 1 and 2 respectively) or the number of broods (IC10 = 10 ng L−1 for strain 3). Moreover, an increase in embryo development abnormalities was observed at the two highest tested malathion concentrations. Abnormalities comprised undeveloped second antennae, curved or unextended shell spines, and curved post-abdomen spines in live neonates. Results suggest that malathion could act as an endocrine disruptor in D. magna as it interferes with development. It also induces a significant decrease in acetylcholinesterase (AChE) activities for the three strains. Both strains 2 and 3 seemed more sensitive (LOECs = 60 ng L−1) than strain 1 (LOEC = 120 ng L−1). Our results suggest that the AChE activity response can also be used as a biomarker of inter-strain (or inter-clonal) susceptibility (i.e. strain (or clone)-specific response).

Effect of deltamethrin (pyrethroid insecticide) on two clones of Daphnia magna (Crustacea, Cladocera): a proteomic investigation.

Deltamethrin is a class II pyrethroid insecticide commonly used in agriculture. It is hazardous to freshwater ecosystems, especially for the cladoceran Daphnia magna (Straus 1820). The results of our previous studies based on acute and chronic ecotoxicity experiments revealed differences in the sensitivity between two different clones. In this work, to investigate deltamethrin toxicity mechanisms in two clones of D. magna, we used a proteomic approach in order to analyze changes in protein expression profiles after 48 h of exposure. We detected 1339 spots; then applying statistical criteria (ANOVA p<0.001 and minimum fold change 1.5), only 128 spots were significantly different in the normalized volume. Among the preselected proteins there were 88 up-regulated and 40 down-regulated proteins. Results showed differences in sensitivities after deltamethrin exposure between the clones. Moreover, using the 2-DIGE method, proteomic investigation for deltamethrin exposure proved to be a reliable and powerful approach to investigate effects of deltamethrin as part of research for new metabolic and cellular biomarkers. After identification by mass spectrometry, there were 39 proteins recognized and identified, in which 21 and 18 were up- and down-regulated, respectively, in deltamethrin-exposed clone A compared to three other conditions (controls of each clone and deltamethrin-exposed clone 2). Up- and down-regulated proteins belonged to 12 biological processes (i.e. metabolic processes, apoptosis and stimulus response) and 5 molecular functions (i.e. catalytic activity, binding, structural molecular activity, antioxidant and receptor activities). Identification of these deregulated proteins opens a new way in discovering new molecular targets and putative biomarkers in daphnids exposed to deltamethrin.

HABITAT AND ASSOCIATED FAUNA OF LITHOPHAGA LITHOPHAGA (LINNÉ 1758) IN THE BAY OF BIZERTA (TUNISIA)

Abstract The Bay of Bizerta (Tunisia) has some sheltered rocky areas that support an important lithophagous fauna. The hard rocky limestone substrata in the bay showed a well-ordered mineralogical structure and the biomicritic matrix contained benthic Foraminifera and ostracod remains dating from Eocene. Monitoring the rocky benthic communities over a period of one year enabled us to study the behavior and the ecology of Lithophaga lithophaga and its associated fauna. The population of this lithophagous bivalve is threatened by unauthorized collecting and the rocky sites are seriously damaged by human activities. The number of individuals of L. lithophaga varies considerably, from one rock block to another, depending on the position and the shape of the substratum. This species usually dominates the zoobenthos community and the associated fauna comprises 29 species (between October 2002 and September 2003). This fauna consists of 8 faunistic groups (Bivalvia, Gastropoda, Polyplacophora, Sipunculoïda, Crustacea, Polychaeta, Echinoderma, and fish).

Altitudinal Distribution of Aquatic Beetles (Coleoptera) in Northern Tunisia: Relationship between Species Richness and Altitude

ABSTRACT An ecological study of the geographical distribution of aquatic Adephaga and Polyphaga (Coleoptera) in the mountains of northern Tunisia was carried out with an analysis of the effect of altitude on the distribution of 123 species collected from 64 sampling sites. Species richness was analyzed at different altitudinal levels and the indicator species were determined by establishing their altitude profile in terms of reciprocal species-factor information. Species richness decreases with increasing altitude. Thirty representative species are placed into three groups: species present along the entire altitudinal gradient; species present at high altitude; and species occurring at low altitude.

Assessment of heavy metal contamination in soil and Chlaenius (Chlaeniellus) olivieri (Coleoptera, Carabidae) in the vicinity of a textile factory near Ras Jbel (Bizerte, Tunisia)

In this study, data on several metals (Cd, Zn, Cu, Ni and Pb) in soil and carabids Chlaenius (Chlaeniellus) olivieri sampled from northeastern Tunisia were presented. Samples were taken at six sites S1, S2, S3, S4, S5 and S6 alongside Kantra River close to three jeans fading industries: Lee Cooper, Denim authority and CRJ. Elemental compositions were assessed through the estimation of geochemical accumulation indices, pollution load index, the contamination factor and bioaccumulation factor (BAF), determined to reveal any potential toxic effects on biota. Significant enrichment of the soil with Cd, Zn, Cu, Ni and Pb was observed in all considered sites and shows a veritable metallic polluted state. The highest concentrations of metals recorded in soil were found at S1. In addition, negative correlation was observed between concentrations of heavy metals in the soil and the species. The BAF values show that C. olivieri is a macro-concentrator for Cd and a micro-concentrator for Zn. The finding provides a rich dataset of metals in several biotas and had operational significance for coexistence of heavy metals in both soil and ground beetles. C. olivieri can be used as a bioindicator in monitoring metals pollution of terrestrial ecosystem. Results can be useful for mitigating the impact of metallic pollution on environmental health and required strategies to prevent such effect.

Beetles (Insecta: Coleoptera) as bioindicators of the assessment of environmental pollution

ABSTRACT Bioindicators have been generating great interest in environmental pollution research. Insects and especially arthropod are useful to assess the effects of anthropogenic activities on the terrestrial ecosystem, because they are inclose contact with toxic elements present in soil and in leaf litter. Beetles are extremely sensitive to several ecological parameters, react quickly to environmental modifications and can be easily and cost-effectively sampled by various methods. These criteria make beetles excellent indicators of terrestrial ecosystem. In order to evaluate the environmental impact of human activities on different ecosystems, the use of Coleoptera in ecological studies has been largely increased in recent years. This review presents the results obtained by researchers when using beetles as bioindicators of metallic pollution and forest disturbance.

Annotated check-list of semi-aquatic bugs of Tunisia, with detailed Faunistic Survey of North Tunisia (Hemiptera: Heteroptera: Gerromorpha)

Abstract During the extensive recent survey, a total of 1655 specimens of Gerromorpha (Hemiptera: Heteroptera) were collected in 51 different localities belonging to five watersheds (Medjerda, North-West watershed, Joumine, Sedjenane, North-East watershed) of the North of Tunisia. Thirteen species belonging to seven genera representing five families were identified. Gerris lacustris (Linnaeus, 1758) and Hebrus montanus (Kolenati, 1857) are new records for Tunisia. The fauna of Gerromorpha from northern Tunisia is provided on the basis of the material newly collected and the collection of the Museum National d’Histoire Naturelle, Paris. All the species of Gerromorpha recorded from Tunisia are catalogued, occurrence of 5 families, 7 genera and 15 species are confirmed, occurrence of two previously recorded species (Rhagovelia nigricans nigricans (Burmeister, 1835), Limnogonus cereiventris (Signoret, 1862) is uncertain and requires confirmation.

Checklist, distribution, and a new record of Nepomorphan water bugs (Hemiptera: Heteroptera) in northern Tunisia

We report on the results of a survey of the Nepomorpha of northern Tunisia, and list twenty-three species belonging to twelve genera and seven families: Nepidae, Ochteridae, Corixidae, Micronectidae, Naucoridae, Notonectidae, and Pleidae. These records are based on intensive field surveys during the year 2013 and examination of the entomological collections of the National Museum Natural History of Paris. Ranatra linearis (Linnaeus, 1758) is recorded for the first time from Tunisia. The occurrence of Sigara (Halicorixa) stagnalis stagnalis (Leach, 1817) in Tunisia is confirmed. A preliminary checklist of the Nepomorpha of Northern Tunisia and updated distribution maps for all species treated are provided for further studies.