The fish fauna of three North African lagoons: specific inventories,ecological status and production

This paper examines the ecological and biological status of fisheries in three coastal lagoons in the southern Mediterranean region: Merja Zerga in Morocco, Ghar El Melh in Tunisia and Lake Manzala in Egypt. Despite similarities in some ecological characteristics, the three lagoons’ respective fisheries show differences in specific composition, in population structure and in their production both in qualitative and quantitative aspects. Thus, in Merja Zerga and Ghar El Melh the fish fauna shows a marine affinity where grey mullet and eels dominate the fish production. In Lake Manzala the ichthyofauna displays a more freshwater affinity with tilapia the dominant group of species. Otherwise, overall fish production at the three sites is regulated by variations in fishing activities, local environments and seasonal conditions. A decrease in fish production was noted over recent years and this is attributed to deteriorating ecological conditions. A variety of factors are implicated including sea communication problems, reduction of the continental (fresh) water supply and increase of pollution causing eutrophication. In addition, over fishing with a continuing increase of fishing effort units, contributes to fisheries decline. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Guest editors: J. R. Thompson & R. J. Flower Hydro-ecological Monitoring and Modelling of North African Coastal Lagoons     

Determination of fuzzy logic membership functions using genetic algorithms: application to structure–odor modeling

Fuzzy logic has been used as a tool in structure–camphoraceous odor relationships. The data base studied included 99 molecules. The rules used to discriminate between camphor and non camphor molecules lead to 77% correct discrimination. Such rules account for the shape and the size of the molecule. Their adjustment by means of genetic algorithms led to 84% correct discrimination between camphor and non-camphor molecules.Figure Membership function for the chosen variables     

Ketamine alters cortical integration of GABAergic interneurons and induces long-term sex-dependent impairments in transgenic Gad67-GFP mice

Ketamine, a non-competitive N-methyl-D-aspartate (NMDA) antagonist, widely used as an anesthetic in neonatal pediatrics, is also an illicit drug named Super K or KitKat consumed by teens and young adults. In the immature brain, despite several studies indicating that NMDA antagonists are neuroprotective against excitotoxic injuries, there is more and more evidence indicating that these molecules exert a deleterious effect by suppressing a trophic function of glutamate. In the present study, we show using Gad67-GFP mice that prenatal exposure to ketamine during a time-window in which GABAergic precursors are migrating results in (i) strong apoptotic death in the ganglionic eminences and along the migratory routes of GABAergic interneurons; (ii) long-term deficits in interneuron density, dendrite numbers and spine morphology; (iii) a sex-dependent deregulation of γ-aminobutyric acid (GABA) levels and GABA transporter expression; (iv) sex-dependent changes in the response to glutamate-induced calcium mobilization; and (v) the long-term sex-dependent behavioral impairment of locomotor activity. In conclusion, using a preclinical approach, the present study shows that ketamine exposure during cortical maturation durably affects the integration of GABAergic interneurons by reducing their survival and differentiation. The resulting molecular, morphological and functional modifications are associated with sex-specific behavioral deficits in adults. In light of the present data, it appears that in humans, ketamine could be deleterious for the development of the brain of preterm neonates and fetuses of addicted pregnant women.Neonatal brain lesions, which affect both preterm and term infants, result in cerebral palsy and cognitive deficits.¹ The main risks associated with these lesions are prematurity, hypoxia-ischemia, hemorrhages, fetal-placental infections and exposure to toxins.^{1, 2} Although the underlying neurochemical processes are complex and only partially elucidated, the production of pro-inflammatory cytokines, free-radical stress induced by both reactive oxygen and nitrogen species, and the massive release of glutamate at both synaptic and extrasynaptic sites, leading to an excitotoxic cell death, have been described.^{3, 4} In particular, because of its high permeability to calcium, the N-methyl-D-aspartate (NMDA) receptor has been shown to have a key role in excitotoxicity, and several studies reported that NMDA receptor antagonists exert a protective effect in both adults and neonates.^{4, 5, 6} However, the innocuousness of NMDA antagonists in the developing brain is debatable. Indeed, several research groups have described a deleterious effect of molecules such as MK801 or memantine in the immature neocortex.^{4, 7, 8, 9} In particular, it has been shown that MK801 exerts a dual effect in cultured cortical slices from mouse neonates; although it reduces excitotoxic death in the deep cortical layers V and VI, it has a pro-apoptotic effect on immature GABAergic interneurons present in the superficial layers II–IV.⁷Because of its short onset of action, rapid clearance and low influence on respiratory and cardiac functions, ketamine is an anesthetic widely used in neonatal pediatrics.^{10, 11} However, similar to MK801, ketamine is a non-competitive NMDA-receptor blocker, and even though its effects are less long-lasting than those of MK801, recent studies point to neurotoxic effects of ketamine in the immature brain of rats and non-human primates.^{12, 13} These reports raise the possibility that ketamine could also have deleterious effects in the developing human brain.¹⁴ Moreover, ketamine is also listed as an illicit drug (named Special K, KitKat or Super K) in most countries and is increasingly used by teens and young adults at raves, with the associated risk of addiction and consumption during pregnancy.^{15, 16} It appears, therefore, that the clinical use of ketamine in pediatrics as well as drug-abuse practices lead to a risk of perinatal exposure during a time-window in which GABAergic interneurons are still differentiating.¹⁷Based on our recent demonstration that MK801 affects the survival of GABAergic interneurons, we hypothesized that ketamine would also interfere with the GABAergic system and result in long-term deficits. Here we tested this hypothesis by using Gad67-GFP transgenic mice to investigate ex vivo and in vivo the effects of prenatal exposure to ketamine on (i) the survival of GABAergic precursors, (ii) the molecular and morphometric characteristics of GABAergic interneuron differentiation, (iii) glutamate-induced neuronal activation and (iv) the long-term impairment of motor activity.     

Palaeolimnological responses of nine North African lakes in the CASSARINA Project to recent environmental changes and human impact detected by plant macrofossil, pollen, and faunal analyses

This paper presents multi-proxy palaeolimnological analyses from recent sediments in the nine CASSARINA lakes in northernmost Africa, three from each of Morocco, Tunisia, and Egypt. The lakes are diverse, ranging from hypersaline to brackish lagoons and fresh-water lakes from high to low conductivity and pH. The macrofossils analysed include fruits, seeds, and vegetative remains of plants, lagoon and fresh-water Mollusca, a range of other aquatic animals, and from one site in each country, Ostracoda and Foraminifera. The diverse macrofossils are multi-proxy indicators of environmental change, and demonstrate changes in response to human activities in the catchments of all the lakes. The three Egyptian Nile Delta lakes have received massive inputs of fresh-water due to modifications of the flow of the R. Nile culminating in the Aswan High Dam built in 1964. Elsewhere, water withdrawal is frequently a serious threat. One lake with high biodiversity in Morocco has been drained and cultivated, and a rare acid-water lake in Tunisia is in danger of drying up. The internationally famous Garaet El Ichkeul in Tunisia, which was so important for birds, has become permanently saline with a loss of diversity. All the lakes are affected by agricultural and/or urban run-off and are experiencing changes as a result of human activities. Several are in a marginally sustainable condition, whereas others are permanently damaged.