Effect of shading imposed by the algae Chaeotomorpha linum loads on structure, morphology and physiology of the seagrass Cymodocea nodosa.

In shallow coastal waters, seagrass and macroalgae occur together but under eutrophic conditions, bloom-forming algae can take over seagrasses causing an irreversible regime shift. Understanding the effect of macroalgae loads on seagrass meadows at an early stage can help prevent the loss of these ecosystems and the services they provide. In the present study, in situ experiments were conducted for 90 days in Bekalta (eastern coast of Tunisia) to assess the response of the seagrass Cymodocea nodosa when challenged with shading induced by filamentous macroalgae Chaetomorpha linum.

Genetic Characterization and Alternative Preservation Ways of Locally Adapted Sheep Breeds: Cases of Private and Public Sheep Sectors in Tunisia and Italy.

Non-commercialized sheep breeds known as local or native breeds are well adapted to their environmental constraints and constitute precious genetic resources that need prioritization for genetic diversity characterization and preservation. The aim of the present study was to assess the genetic diversity level and the related preservation decisions of very old and traditional native Mediterranean sheep breeds from Tunisia and Italy using 17 microsatellite markers. In total, 975 sheep were sampled from five Tunisian, one Center Italian, and four Venetian native breeds.

Historical Westward Migration Phases of Inferred from the Population Structure and the Phylogeography of Occidental Mediterranean Native Sheep Breeds.

In this study, the genetic relationship and the population structure of western Mediterranean basin native sheep breeds are investigated, analyzing Maghrebian, Central Italian, and Venetian sheep with a highly informative microsatellite markers panel. The phylogeographical analysis, between breeds' differentiation level (Wright's fixation index), gene flow, ancestral relatedness measured by molecular coancestry, genetic distances, divergence times estimates and structure analyses, were revealed based on the assessment of 975 genotyped animals. The results unveiled the past introduction and migration history of sheep in the occidental Mediterranean basin since the early Neolithic.

Genetic Variability and Population Structure of the Tunisian Sicilo-Sarde Dairy Sheep Breed Inferred from Microsatellites Analysis.

This study analyzed the genetic variability, inbreeding and population structure of the Tunisian-North African dairy sheep breed, the Sicilo-Sarde (SS), created by crossing the Sarda and Comisana dairy breeds. The level of variability in the SS, considered as an endangered breed after a dramatic decrease, was assessed using 17 microsatellite markers by analyzing the two breed populations sampled from their respective cradles: SS of Beja (SS, = 27) and SS of Mateur (SS, = 25). High levels of genetic diversity in SS were revealed, with a total of 212 alleles, a high mean number of alleles (12.

A comparative study of trace elements in Cymodocea nodosa from three semi-enclosed coastal areas in Tunisia.

The present study quantifies the levels of five trace elements (TEs) Zn, Cu, Ni, Pb, and Cd in the leaves and rhizomes of Cymodocea nodosa as well as the surficial sediments from three semi-enclosed coastal areas in Tunisia, in the south Mediterranean Sea. Samples were taken from the Bizerte and Ghar El Melh lagoons and from marina Cap Monastir. The TE ranking was found to be Zn > Cu > Pb > Ni > Cd in sediments and Zn > Cu = Ni = Pb = Cd in C.

Contribution of microsatellites markers in the clarification of the origin, genetic risk factors, and implications for conservation of Tunisian native sheep breeds.

The genetic diversity and genetic relationship of the two main groups of African sheep, thin-tailed and fat-tailed sheep, represented by the indigenous Tunisian sheep breeds "Barbarine" (BAR, fat-tailed) and "Queue Fine de l'Ouest" (QFO, thin-tailed) were investigated. The genotypes of 110 animals belonging to these two breeds and their crossbreed (CRO) were assessed using 17 microsatellite markers. The results showed high levels of genetic diversity and a total of 256 alleles were identified in the whole population.

Variation along the year of trace metal levels in the compartments of the seagrass Posidonia oceanica in Port El Kantaoui, Tunisia.

The accumulation of the five trace metals (TMs) cadmium, copper, lead, nickel and zinc was measured in Posidonia oceanica leaves. Shoots were seasonally sampled at 8-10-m depth from four stations located in Port El Kantaoui area, Tunisia, during four campaigns performed in 2012. Levels of the five TMs were analyzed using inductively coupled plasma atomic emission spectrometry (ICP-AES) in three compartments of P.

Abundance and diversity of amphipods (Crustacea: Peracarida) on shallow algae and seagrass in lagoonal ecosystem of the Mediterranean Tunisian coast.

Background: Bizerte lagoon is a semi-enclosed marine ecosystem, where various types of human activities have been developed. To investigate the distribution and temporal variation of amphipod assemblage, monthly sampling was conducted at the Menzel Jemil site from October 2009 to September 2010.

Results: Atotal number of 3,620 specimens were collected from floating algae and seagrass allowing the identification of 10 amphipod species.

Widespread Wolbachia infection in terrestrial isopods and other crustaceans.

Wolbachia bacteria are obligate intracellular alpha-Proteobacteria of arthropods and nematodes. Although widespread among isopod crustaceans, they have seldom been found in non-isopod crustacean species. Here, we report Wolbachia infection in fourteen new crustacean species.

[Phenetic analysis of populations of Porcellionides pruinosus (Brandt, 1833) (Crustacea, Isopoda, Oniscidea)].

The cosmopolitan species, Porcellionides pruinosus (Brandt, 1833), exhibited a geographical variation of its morphological features and its reproduction pattern. In fact, some Tunisian populations had a seasonal reproductive period and other ones showed a reproductive activity. A phenetic analysis has been performed to compare populations belonging to P.

Life cycle and population dynamic of Armadillidium pelagicum Arcangeli, 1955 (Isopoda, Oniscidea) at Aouina.

Armadillidium pelagicum Arcangeli, 1955 is a terrestrial isopod endemic to the circum-Sicilian islands and the North of Tunisia. The life cycle and the population structure of this species were studied on a natural population at Aouina, in the surroundings of Tunis, over 16 months from, January 2000 to April 2001, by monthly or semi-monthly samplings. The ovigerous females were present from March/April to the end of August and absent from September to February/March.

[Reproductive phenology of a natural population of Armadillidium pelagicum Arcangeli, 1955 (Isopoda, Oniscidea)].

Armadillidium pelagicum, the most abundant species of the genus in Tunisia is endemic to the North of Tunisia and the circumsicilian islands. In the laboratory and under the natural conditions of temperature and photoperiod, virgin females of A. pelagicum exhibit a spontaneous ovarian maturation, followed by a parturial moult.

[Biology and population dynamics of Porcellionides sexfasciatus (Crustacea, Isopoda, Oniscidea)].

The biology and the population dynamics of Porcellionides sexfasciatus Budde-Lund (1879) were studied on a field and carried out at Garat Nâam (Kasserine, Tunisia) from July 1996 to June 1998. The reproduction exhibited a seasonal pattern extending from February/March to October/November. The juveniles appeared in the population from April to November.

[Seasonal reproduction of Porcellio variabilis Lucas, 1846].

Porcellio variabilis is common and very widespread in Tunisia. Its breeding period lasts from February to October with a cessation during the months of November, December and January. The recruitment of young takes place principally between April and July.

[The Cymothoidae (isopod parasites of marine fishes) of the coast of Tunisia: ecology and parasitological index].

The study of the cymothoid isopod parasites on marine fishes from Tunisian localities has allowed us to distinguish eight species, seven of which have already been recorded and one, Mothocya epimerica which is new to the region. New hosts for Cerathotoa parallela and Nerocila orbignyi are reported. For each parasite species collected, the host fish, the parasitic specificity and the parasitological index are given.

[Esterase and amylase: two biochemical markers in the polytypic Idotea chelipes (crustacea, isopoda valvifera)].

In polytypic Idotea chelipes species, the slow esterase constitutes a subspecific biochemical marker which discriminates, without ambiguity, each of three subspecies. Amylase 2 is a diagnostic locus which separates I. chelipes bocqueti from the two other subspecies where each is characterized by particular frequencies of the most frequent allele.

[Electrophoresis study of hemocyanin of the polytypic species Idotea chelipes and Idotea balthica basteri (Crustacea Isopoda)].

Hemocyanin has been used as a protein marker for Crustacea speciation. The specificity of the hemocyanin fractions of two Idotea species has been confirmed by mono and bidirection electrophoresis. Four protein fractions have been found in the two Idotea species.