Inferring the roles of vicariance,climate and topography in population differentiation in Salamandra algira (Caudata,Salamandridae)

Integrating information from species occurrence data, environmental variables and molecular markers can provide valuable insights about the processes of population persistence and differentiation. In this study, we present the most comprehensive overview of the evolutionary history of the North African salamander Salamandra algira (Caudata, Salamandridae) to date, including analyses of climatic and topographical variables, and sequences of two mitochondrial and two nuclear DNA fragments, with a special focus on Algerian populations, under‐represented in previous studies. Coalescent‐based phylogenetic analyses of mtDNA data recover four well‐supported population groups corresponding to described subspecies, with a western clade including populations in north‐western Morocco (with two subclades corresponding to the subspecies tingitana and splendens), and an eastern clade including populations from north‐eastern Morocco (subspecies spelaea) and Algeria (subspecies algira). Inferred split times between major clades date back to the Miocene, with additional splits within each major clade in the Plio‐Pleistocene. Present climatic (aridity) and topographical factors account for geographical discontinuities across population groups and help identify potential areas of secondary contact between clades corresponding to the subspecies tingitana and splendens in the Rif mountains in Morocco. Niche analysis indicates the absence of phylogenetic signal in the use of environmental space in this species.     

Conjunctival myiasis. 23 cases in the Tunisian Sahel

Conjunctival lesions of ocular myiasis are common in the mediterranean region. The authors report 23 cases of conjunctival myiasis. This affection is caused by fly's larvae: Oestrus ovis presenting typically with inflamed and oedematous eyes. We diagnose the affection by directly showing the larvae on conjunctiva. The treatment consisted to extirpate larvae one by one.     

Mycocoenologic study of the macrofungi on the forest of Jbel elbir (Aïn Draham,Jendouba, Tunisia)

Macrofungi have important functions in forest ecosystems. It is essential to have information about these species to ensure proper management of such ecosystems. Due to the importance of forestry in Tunisia and the lack of information on fungal communities, this study was conducted in North Western of Tunisia. The objective was to enumerate macrofungal diversity in relation to various environmental factors. In total, 158 fruiting bodies were collected and 60 species were identified. Among them, 39 species are mycorrhizal. A fruiting body is the first visible appearance of the spore‐bearing surface until its disintegration. More fruiting bodies were found on the eastern slopes than on the western slopes. This reflects the distribution of tree species and soil type. Almost all fungal species were collected from soils of moderate acidity (pH 4–pH 5), 5 species from soils with low acidity (pH 5–pH 6.8), and only 3 species from soils with high acidity (pH < 4). The majority of fruiting bodies occurred in soils with a percentage of organic matter ranging from 1 to 5 and a phosphorus content ranging from 15.1 to 20 ppm.     

A novel frameshift mutation in BLM gene associated with high sister chromatid exchanges (SCE) in heterozygous family members

The Bloom syndrome (BS) is an autosomic recessive disorder comprising a wide range of abnormalities, including stunted growth, immunodeficiency, sun sensitivity and increased frequency of various types of cancer. Bloom syndrome cells display a high level of genetic instability, including a 10-fold increase in the sister chromatid exchanges (SCE) level. Bloom syndrome arises through mutations in both alleles of the BLM gene, which was identified as a member of the RecQ helicase family. In this study, we screened a Tunisian family with three BS patients. Cytogenetic analysis showed several chromosomal aberrations, and an approximately 14-fold elevated SCE frequency in BS cells. A significant increase in SCE frequency was observed in some family members but not reaching the BS patients values, leading to suggest that this could be due to the heterozygous profile. Microsatellite genotyping using four fluorescent dye-labeled microsatellite markers revealed evidence of linkage to BLM locus and the healthy members, sharing higher SCE frequency, showed heterozygous haplotypes as expected. Additionally, the direct BLM gene sequencing identified a novel homozygous frameshift mutation c.3617–3619delAA (p.K1207fsX9) in BS patients and a heterozygous BLM mutation in the family members with higher SCE frequency. Our findings suggest that this latter mutation likely leads to a reduced BLM activity explaining the homologous recombination repair defect and, therefore, the increase in SCE. Based on the present data, the screening of this mutation could contribute to the rapid diagnosis of BS. The genetic confirmation of the mutation in BLM gene provides crucial information for genetic counseling and prenatal diagnosis.     

Plasmodial Aspartyl-tRNA Synthetases and Peculiarities in Plasmodium falciparum

Distinctive features of aspartyl-transfer RNA (tRNA) synthetases (AspRS) from the protozoan Plasmodium genus are described. These apicomplexan AspRSs contain 29–31 amino acid insertions in their anticodon binding domains, a remarkably long N-terminal appendix that varies in size from 110 to 165 amino acids and two potential initiation codons. This article focuses on the atypical functional and structural properties of Plasmodium falciparum cytosolic AspRS, the causative parasite of human malaria. This species encodes a 626 or 577 amino acids AspRS depending on whether initiation starts on the first or second in-frame initiation codon. The longer protein has poor solubility and a propensity to aggregate. Production of the short version was favored as shown by the comparison of the recombinant protein with endogenous AspRS. Comparison of the tRNA aminoacylation activity of wild-type and mutant parasite AspRSs with those of yeast and human AspRSs revealed unique properties. The N-terminal extension contains a motif that provides unexpectedly strong RNA binding to plasmodial AspRS. Furthermore, experiments demonstrated the requirement of the plasmodial insertion for AspRS dimerization and, therefore, tRNA aminoacylation and other putative functions. Implications for the parasite biology are proposed. These data provide a robust background for unraveling the precise functional properties of the parasite AspRS and for developing novel lead compounds against malaria, targeting its idiosyncratic domains.Aminoacyl-tRNA synthetases (aaRSs)² are ubiquitous enzymes that attach amino acids to their cognate transfer RNAs (tRNAs) during protein synthesis. In ensuring high fidelity of tRNA aminoacylation, they maintain the genetic code and consequently contribute to cell viability in all forms of life. aaRSs are divided into two classes depending on the architectural organization of their catalytic domains and the way that they recognize their tRNA substrates. They have modular architectures which exhibit overall evolutionary conservation but also idiosyncratic features that indicate their phylogenetic origins (1). Such features are potential targets for aaRS inhibitors and, thus, for antipathogenic compounds. In addition to their important role in protein synthesis, aaRSs have developed a large panel of new functions during their evolutionary history that impact cell physiology and dysfunctions in ways that are not well understood (2, 3).Within the aaRS family, aspartyl-tRNA synthetases (AspRS) are among the most thoroughly investigated for both structural and functional aspects (4–11). AspRSs are dimeric proteins that belong to class IIb synthetases. Their subunits have a conserved modular architecture in the three kingdoms of life with a C-terminal catalytic module linked by a short hinge domain to an N-terminal anticodon binding module. An additional domain is found on the N-terminal module of eukaryotic AspRSs that has been shown in the case of the Saccharomyces cerevisiae enzyme to help anchor the tRNA to the enzyme core (12) (see Fig. 1A). However, despite the large amount of data collected, our understanding of AspRSs is incomplete as enzymes originating from entire classes in the tree of life have not been studied. This is the case with eukaryotic AspRSs and, among them, those of the genus Plasmodium.Open in a separate windowFIGURE 1.Overall organization of plasmodial AspRS sequences (numbering is according to P. falciparum protein or gene sequence). A, modular arrangement of AspRSs with features important to structure and function indicated. The three modules of the AspRS core are shown in heavy lines together with the eukaryotic and prokaryotic N and C-terminal extensions (and the N-terminal organellar signals) in light lines. Novel domains in Plasmodium AspRSs are in black; domains strictly present in all AspRSs are in gray (motifs 1, 2, 3 are class II aaRS-specific, flipping loop is AspRS-specific, and RNA binding motif is specific of eukaryotic AspRSs except those from mammals and birds). B, sequence alignment of Plasmodium AspRSs with the RNA binding motif and plasmodial insertion boxed and predicted secondary structure elements in the N-terminal eukaryotic extension indicated. Large numbers delineate structural modules; dots indicate the two methionine residues coded by in-frame ATG codons. Protein sequences are from PlasmoDB: P. reichenowi (Partial Genome Shotgun, join reich314f03.plk and reich249e05.plk), P. falciparum (PFA0145c), P. vivax (Pv081610), P. knowlesi (PKH_021050), P. berghei (PB000914.03.0), and P. yoelii (PY01511). C, sequence alignment of mRNA 5′-ends from Plasmodium AspRSs. Only sequences surrounding the two in-frame ATG codons are displayed and compared with the Kozak consensus sequence. The untranslated region (UTR) sequences preceding the first ATG are in italics. Notice the better fit of sequences around the second ATG with the Kozak consensus.To date nothing is known about plasmodia AspRSs; in fact, all aaRSs (and translation in general) in the Plasmodium genus remain unstudied despite the acute medical importance of these parasites that cause malaria. Plasmodia belong to the Apicomplexa, a phylum of the alveolates (unicellular protists) (13) close to fungi and plants (14). Among the several species that infect humans, Plasmodium falciparum causes the most deadly form of malaria. Each year it infects 600 million people and causes three million deaths (see the Malaria Foundation International website). Plasmodia contain three genomes; in their nuclei, in their mitochondria, and in their apicoplasts, a secondary plastid. The three complete genomes of P. falciparum have been sequenced, namely a 23-megabase nuclear genome divided between 14 chromosomes (15), a 6-kilobase mitochondrial genome (16) and a 35-kilobase apicoplastic genome (17). Altogether 5300 protein genes were predicted, including ∼35 aaRS genes of the highly conserved genes coding for proteins involved in translation (cytosolic and apicoplastic), all encoded in the nuclear genome. The nuclear genome also contains 43 tRNA genes (Genomic tRNA Database) (18). Noticeably, the small mitochondrial genome is devoid of both aaRS and tRNA genes, whereas the apicoplastic genome codes only tRNAs (19, 20). Thus, for translation to occur in the organelles implies the import of tRNA and aaRSs.Based on known genomic sequences, this work analyzes the structure of plasmodial AspRSs and demonstrates their similarity to S. cerevisiae and Homo sapiens homologs. Interestingly, it also reveals peculiarities not previously observed in other AspRSs, in particular an insertion in the anticodon binding domain and an extra long N-terminal extension. The AspRS from P. falciparum was chosen for more thorough investigation. The protein was overexpressed in Escherichia coli and its distinctive physicochemical and biochemical properties were established and compared with those of its human host counterpart. The implications of these new findings are discussed.     

Effect of glutamine on post-thaw motility of bull spermatozoa after association with LDL (low density lipoproteins) extender: Preliminary results

Glutamine has been used in the composition of semen extenders in several species, but never in the bull. The aim of our study is to demonstrate the cryoprotective role of glutamine for freezing bovine semen and to determine concentration of the latter to improve the motility and trajectory characteristics of spermatozoa. Three experiments were undertaken with 21 ejaculates from three different bulls. In the first experiment, glutamine was added to 40, 80, and 120 mM of basic medium (BM) which consisted of Tris + glycerol 6.4% (v/v). In the second experiment glutamine was added to the 8% low density lipoprotein (LDL) diluent at 40, 80, and 120 mM. In the third experiment, the best concentration of glutamine was determined; this was then added to the LDL extender at 10, 20, 30, and 40 mM. The semen was diluted then frozen in the different media. Motility parameters were assessed using an image analyser following thawing. Experiment 1 demonstrated that glutamine had a cryoprotective effect; at 40 mM it gave superior motility parameters to those obtained with the basic medium (p < 0.05). Experiment 2 demonstrated that the combination of LDL-glutamine 40 mM and 80 mM did not improve motility and even deteriorated it in comparison with the glutamine-free LDL extender. Experiment 3 demonstrated that the addition of 10 mM of glutamine to the LDL medium lead to a significant improvement (p < 0.05) in the motility of bull spermatozoa and could be used to improve bovine semen extenders.     

Compared parasitic infection of Ligula intestinalis (Cestoda: Diphyllobothridae) in Cyprinidae species: Rutilus rubilio and Scardinius erythrophthalmus in two dam reserves in Tunisia

Monitoring quantitative parameters of parasitism by ligula intestinalis (Cestoda: Diphyllobothridae) was performed by examining 516 fish belonging to two introduced freshwater species: Rutilus rubilio (350 individuals) and Scardinius erythrophthalmus (166 individuals). These fish were collected in two dam reserves in Tunisia, Sidi Salem and Nebhana. The analysis of the aquatic bird's composition in these two reserves revealed the existence of piscivorous bird species that were previously reported as final host of Ligula. Monitoring the bird's composition highlighted higher relative abundance and frequency in Sidi Salem than in Nebhana dam reserve. The analyses of the prevalence, mean intensity and abundance of the parasite revealed the most important values in roach, Rutilus rubilio which seems to be the preferential second intermediate host of the parasite Ligula intestinalis in these environments. Comparative analysis of parasitism in both explored sites suggests that Ligula intestinalis presents two different strategies of infestation. In Sidi Salem reserve, which is larger than Nebhana and containing on important and diversified piscivorous species, the parasite infects a maximum of host individuals with low parasite mean intensity values. However, at Nebhana, which is a smaller reserve, the parasite infects fewer individuals than Sidi Salem but with higher mean intensity. The highest prevalence values were recorded in large size classes of roach species in Sidi Salem reserve.     

First occurrence of the yellow roughneck shrimp, <Emphasis Type="Italic">Rimapenaeus similis</Emphasis> (Smith, 1885) (Crustacea: Decapoda: Penaeidae) in the Mediterranean Sea (Tunisian waters)

During an experimental trawl survey carried out by the R/V “Hannibal” in June 2006 several specimens of the Western-Atlantic penaeid shrimp Rimapenaeus similis (Smith, 1885) were caught in the Gulf of Gabes (southern Tunisia, Central Mediterranean). This represents the first recording of Rimapenaeus similis in Tunisian waters and for the Mediterranean Sea. Biological information on the sampled population is also included.     

La gangrène des organes génitaux externes de I’homme: Facteurs de risque et de pronostic

The objective of this study, based on 20 cases of necrotizing fasciitis of the male genitalia, is to identify the risk factors and prognostic factors of this disease. Most cases of necrotizing fasciitis of the male genitalia occurred in elderly men with a poor socio-economic level including 9 diabetics. There was no identifiable cause in 8 cases (Fournier’s gangrene). All patients underwent surgical excision and systematic antibiotic therapy. This series comprised 5 deaths (25%) in patients over the age of 69 years with extensive lesions and a very poor general state on admission. The outcome of survivors was favourable after a prolonged hospital stay (mean stay: 1 month). The clinical context therefore appears to play an essential role in the development of this disease and its subsequent prognosis, which could be improved by rapid and appropriate prevention and treatment.     

Disruption of insulin pathways alters trehalose level and abolishes sexual dimorphism in locomotor activity in Drosophila

Insulin signaling pathways are implicated in several physiological processes in invertebrates, including the control of growth and life span; the latter of these has also been correlated with juvenile hormone (JH) deficiency. In turn, JH levels have been correlated with sex-specific differences in locomotor activity. Here, the involvement of the insulin signaling pathway in sex-specific differences in locomotor activity was investigated in Drosophila. Ablation of insulin-producing neurons in the adult pars-intercerebralis was found to increase trehalosemia and to abolish sexual dimorphism relevant to locomotion. Conversely, hyper-insulinemia induced by insulin injection or by over-expression of an insulin-like peptide decreases trehalosemia but does not affect locomotive behavior. Moreover, we also show that in the head of adult flies, the insulin receptor (InR) is expressed only in the fat body surrounding the brain. While both male and female InR mutants are hyper-trehalosemic, they exhibit similar patterns of locomotor activity. Our results indicate that first, insulin controls trehalosemia in adults, and second, like JH, it controls sex-specific differences in the locomotor activity of adult Drosophila in a manner independent of its effect on trehalose metabolism.