Patterns of evolution in MHC class II DQA and DQB exon 2 genes of Alpine mountain hares, Lepus timidus varronis, and sympatric and parapatric brown hares, L. europaeus, from Switzerland.

In natural populations, hybridization is known to occur between a wide range of species. However, its evolutionary significance is less clear. Genes involved in fighting pathogens are considered excellent candidates for studying adaptive introgression, although both introgression and balancing selection can generate similar patterns of diversity and differentiation. Here, we compared DQA and DQB MHC class II and microsatellite allelic diversity of sympatric and parapatric mountain (Lepus timidus) and brown hare (L. europaeus) populations from Switzerland. We detected higher genetic diversity in brown hares compared to mountain hares at both MHC and microsatellite loci. We consider the observed patterns of microsatellite diversity both for L. europaeus and L. timidus as result of stochastic demographic processes while the pattern of MHC polymorphism of the studied hare populations can be explained by pathogen-driven selection. Rare bidirectional gene flow between both hare species seems to occur specifically for MHC alleles. However, the high number of shared alleles showing similar high frequency in both species suggests that reciprocally exchanged MHC alleles are being maintained via balancing selection. Adaptation to similar pathogen communities can also lead to parallel selection of MHC alleles. Positive selection, recombination and mutations have played different roles in shaping the patterns of MHC allelic diversity in and differentiation between both species. Results for the latter evolutionary forces do not show a better matching between the sympatric populations compared to the parapatric ones, suggesting a minor role of introgression for the observed evolutionary patterns of the studied hare species.

Identification and characterization of novel NBS-LRR resistance gene analogues from the pea.

Pea (Pisum sativum) is one of the most cultivated le-gumes in the world, and its yield and seed quality are affected by a variety of pathogens. In plants, NBS-LRR (nucleotide binding site-leucine-rich repeat) is the main class of disease resistance genes. Using degenerate primers deduced from conserved motifs in the NBS domain of known resistance genes, we identified 10 NBS sequences in three varieties of P. sativum. The deduced amino acid sequences of the iden-tified resistance gene analogues (RGAs) exhibited the typical motifs of the NBS domain (P-loop, kinase-2, kinase-3a, and the hydrophobic domain, GLPL) present in the majority of plant proteins belonging to the NBS-LRR class. Phylogenetic analysis showed that seven RGAs belonged to the non-TIR-NBS-LRR subclass and three to the TIR-NBS-LRR subclass. The results of this study provide insights into the structure of this class of resistance genes in the pea, and their evolution-ary relationships with those of other plant species.

Molecular characterization of barley yellow dwarf virus in Tunisia.

Barley yellow dwarf disease is a worldwide ubiquitous virus disease of cereal crops. In order to characterize the B/CYDV isolates occurring in Tunisia, 240 barley leaves were randomly sampled from 6 fields following a North-South trend and analyzed by serological and molecular tests. DAS-ELISA results showed 40 positive samples with a prevalence of barley yellow dwarf virus (BYDV)-PAV (77.5%), followed by cereal yellow dwarf virus (CYDV)-RPV (25%) and BYDV-MAV (15%). Studies of the geographic distribution showed a high incidence of B/CYDV in the Tunisian Southern provinces. RT-PCR assays were performed to amplify the viral coat protein gene (CP) and sequence analyses revealed six BYDV-PAV haplotypes named PAV-TN1 to PAV-TN6. Phylogenetic analysis showed that the six Tunisian haplotypes were close to BYDV-PAV-II subspecies and had a strong similarity with Moroccan, Czech, French and German haplotypes. Although PAV-TN2 and PAV-TN5 showed up to 10% divergence from BYDV-PAV-II at the amino acid level, it seems to belong to the same subspecies but in a separated cluster. Our results will be important in developing appropriate control measures against BYDV disease in Tunisia.

First Report of Sugarcane yellow leaf virus Infecting Barley in Tunisia.

Sugarcane yellow leaf virus (ScYLV) causes severe leaf symptoms in sugarcane (Saccharum spp.). It is a single-stranded RNA virus assigned to the genus Polerovirus, family Luteoviridae (1). ScYLV is transmitted by two aphid species, Melanaphis sacchari and Rhopalosiphum maidis. Although barley (Hordeum vulgare), oats (Avena sativa), and wheat (Triticum spp.) are susceptible to ScYLV when experimentally inoculated (3), this virus, related serologically to Barley yellow dwarf virus (BYDV)-RPV (4), has never been detected naturally in these cereals. In this study, 240 barley leaves were randomly collected from six fields in Tunisia following a north-south trend during the high infestation periods (March/April) in the 2013 growing season. Samples were tested by DAS-ELISA, using three antibodies (Bioreba AG, Switzerland), two of them, BYDV-B and BYDV-F, specific to luteoviruses corresponding to BYDV-PAV and BYDV-MAV, respectively, and the third one, BYDV-RPV, specific to the polerovirus synonymous to Cereal yellow dwarf virus (CYDV)-RPV. Based on DAS-ELISA, 30 samples were found positive for B/CYDV infection; 17 out of the 30 infected samples contained a single serotype, BYDV-PAV, and 13 out of the 30 infected samples contained two serotypes, PAV and RPV. Total RNA was extracted from all positive samples, and RT-PCR of the viral CP gene was performed with Lu1/Lu4 primers (2). A product of 531 bp was cloned and sequenced. The identities among the sequences determined varied between 80 to 100%, and from the 17 samples containing BYDV-PAV, six distinct BYDV-PAV sequences were revealed and named PAV-TN1 to PAV-TN6 (GenBank Accession No. JX402453 to JX402457 and KF271792). Fortuitously, all 13 positive samples corresponding to the serotypes PAV-RPV exhibited 98.7 to 99.3% identity with ScYLV isolates. These 13 samples contained three distinct sequences that were named ScYLV-Tun1 to ScYLV-Tun3 (GenBank Accession No. KF836888 to KF836890). Of the 17 PAV-positive samples collected, six were infected with PAV-TN1, four with PAV-TN2, four with PAV-TN3, one with PAV-TN4, one with PAV-TN5, and the last one with PAV-TN6. Of the 13 ScYLV-positive samples, seven were infected with ScYLV-Tun1, four with ScYLV-Tun2, and two with ScYLV-Tun3. Phylogenetic analysis showed that PAV-TN sequences formed a very tight cluster (>98%) corresponding to BYDV subspecies PAV-II, whereas all three Tunisian ScYLV sequences were clustered together. This study provides the first report of ScYLV isolates infecting barley crops in Tunisia, and confirms serological cross-reactivity between ScYLV and BYDV-RPV when commercial antibodies against BYDV-RPV are used. References: (1) C. J. D'Arcy and L. L. Domier. Page 891 in: Virus Taxonomy, 8th Report of the ICTV. C. M. Fauquet et al., eds. Springer-Verlag, New York, 2005. (2) N. L. Robertson and R. French. J. Gen. Virol. 72:1473, 1991. (3) S. Schenck and A. T. Lehrer. Plant Dis. 84:1085, 2000. (4) J. Vega et al. Plant Dis. 81:21, 1997.

Carbon tetrachloride-induced nephrotoxicity and DNA damage in rats: protective role of vanillin.

In this study, the protective effects of vanillin were evaluated against carbon tetrachloride (CCl(4))-induced kidney damages in Wistar albino rats. CCl(4) (1 ml/kg, intraperitoneally [i.p.]) caused a significant induction of renal disorder, oxidative damage and DNA fragmentation as evidenced by increased plasma creatinine, urea and uric acid levels, increased lipid peroxidation (malondialdehyde [MDA]) and protein carbonyl. Furthermore, glutathione levels, catalase, superoxide dismutase, glutathione transferase and glutathione peroxidase activities were significantly decreased. A smear without ladder formation on agarose gel was also shown, indicating random DNA degradation. Pretreatment of rats with vanillin (150 mg/kg/day, i.p.), for 3 consecutive days before CCl(4) injection, protected kidney against the increase of MDA and degradation of membrane proteins compared to CCl(4)-treated rats and exhibited marked prevention against CCl(4)-induced nephropathology, oxidative stress and DNA damage. Kidney histological sections showed glomerular hypertrophy and tubular dilatation in CCl(4)-treated rats, however, in vanillin pretreated rats, these histopathological changes were less important and present a similar structure to that of control rats. These data indicated the protective role of vanillin against CCl(4)-induced nephrotoxicity and suggested its significant contribution of these beneficial effects.

Spatial and temporal genetic variation in Tunisian field populations of Macrosiphum euphorbiae (Thomas).

The potato aphid Macrosiphum euphorbiae (Thomas) is a major pest of several economic crops in Tunisia. Using 10 microsatellites, we analyzed five populations of M. euphorbiae sampled during the 2004-2005 solanaceous and cucurbit season (April through September) from five geographic origins. From 235 aphids, 61 different multilocus genotypes were identified of which three genotypes MLG1, MLG2, and MLG42 were predominant on all host plants and regions. MLG1 and MLG2 genotypes were detected in 2004 and did not reappear in spring 2005, while the genotype MLG42 was detected only in 2005. All populations showed significant deviation from Hardy-Weinberg equilibrium even in data sets including one individual per genotype. χ(2) independence tests and analysis of molecular variance showed no significant differentiation among populations collected on different host plant and from different geographic origin, but differences between populations from two successive years were significant. Factorial component analysis corroborates these results. The probable causes of this seasonal variation were discussed.

Hypolipidemic and hepatoprotective effects of flax and pumpkin seed mixture rich in omega-3 and omega-6 fatty acids in hypercholesterolemic rats.

Flax and pumpkin seeds are a rich source of unsaturated fatty acids, antioxidants and fibers, known to have anti-atherogenic and hepatoprotective activities. These effects were evaluated in Wistar rats fed with 1% cholesterol diet. The study was performed on 30 male rats divided into three groups: a control group (CD), CD-chol group fed diet with 1% cholesterol and MS-chol group fed diet enriched with flax and pumpkin seed mixture. In CD-chol group, total cholesterol TC, triacylglycerol TG in plasma and liver, plasma LDL-C, atherogenic index AI and LDL/HDL ratio significantly increased. In MS-chol group lipid parameters decreased significantly, plasma and liver fatty acid composition showed an increase of PUFAs (ALA and LA), and MUFAs (oleic and eicosaenoic acid) and a decrease of SFA (palmitic and stearic acid). In plasma and liver of MS-chol group, malondialdehyde levels decreased and the efficiency of antioxidant defense system was improved compared to CD-chol group. Liver histological sections showed lipid storage in hepatocytes of CD-chol group and an improvement was noted in MS-chol group. Our results suggested that flax and pumpkin seed mixture had anti-atherogenic and hepatoprotective effects which were probably mediated by unsaturated fatty acids present in seed mixture.

Genotypic diversity of the cotton-melon aphid Aphis gossypii (Glover) in Tunisia is structured by host plants.

The study of intraspecific variation with respect to host plant utilization in polyphagous insects is crucial for understanding evolutionary patterns of insect-plant interactions. Aphis gossypii (Glover) is a cosmopolitan and extremely polyphagous aphid species. If host plant species or families constitute selective regimes to these aphids, genetic differentiation and host associated adaptation may occur. In this study, we describe the genetic structure of A. gossypii collected in six localities in Tunisia on different vegetable crops, on citrus trees and on Hibiscus. The aim was to determine if the aphid populations are structured in relation to the host plants and if such differentiation is consistent among localities. The genetic variability of A. gossypii samples was examined at eight microsatellite loci. We identified only 11 multilocus genotypes among 559 individuals. Significant deviations from Hardy-Weinberg equilibrium, linkage disequilibria and absence of recombinant genotypes, confirmed that A. gossypii reproduces by continuous apomictic parthenogenesis. Genetic differentiation between localities was not significant, whereas a strong differentiation was observed between host plant families (0.175

Nucleotide sequence comparison of the 3' terminal region of the genome of pepper vein mottle virus isolates from Tunisia and Ivory Coast.

Three Tunisian PVMV isolates identified in pepper and tomato fields and one isolate from Ivory Coast were submitted to biological and molecular analysis. Phenotypically, Tunisian isolates induced mild symptoms while the Ivory Coast one is more aggressive on tobacco. As no PVMV sequence data are available, detailed sequence comparisons of coat protein gene (CP) were made. No nucleotide or amino acid changes in this region could be related to the pathogenicity of the isolates analysed. With the aim to increase our molecular understanding of the biological properties, we have sequenced the 3'-non translated region (3'NTR). Results suggest that this region of the RNA genome may be involved in the modulation of disease symptoms.

Cell-free cloning and biolistic inoculation of an infectious cDNA of potato virus Y.

Potato virus Y (PVY) full-length cDNA has been found to be refractory to cloning in Escherichia coli cells. A full-length 9.7 kb PVY cDNA was obtained by reverse transcription polymerase chain reaction (RT-PCR) from the RNA of PVY (tuber necrotic strain, PVYNTN). Double-stranded DNA fragments were used as primers (ds megaprimers), to include signals for transcription in vivo (a cauliflower mosaic virus 35S RNA promoter and a nopaline synthase terminator) in the final PCR product. Biolistic bombardment with a helium particle gun was used to inoculate the amplified product to detached tobacco leaves. Inoculation of tobacco plants with ground inoculated leaves followed by northern blot, ELISA and immuno-electron microscopy demonstrated that the DNA was highly infectious with up to 90% of bombarded leaves containing the virus. This methodology will allow the use of reverse genetics in the study of PVY-plant interactions and will also be useful for obtaining infectious cDNA from other viruses with large RNA genomes.

[Contribution of "bobbed" phenotype to the magnification of ribosomal DNA in Drosophila melanogaster]. / Contribution du phénotype "bobbed" à la magnification de l'ADN ribosomal chez Drosophila melanogaster.

Phenotype and magnification of two bobbed mutations allelic to the XNO region were studied at various temperatures. Results showed that magnification increases with increased severity of bobbed phenotype in that the reversion of the bbT6 allele is the same at high and low temperature whereas the thermosensitive bbP5 allele shows increased reversion at high temperature. Temperature shift experiments carried out during the development of premagnified males show that magnification which is followed by selection stage occurs during embryogenesis.

[The role of culdocentesis in the diagnosis of ectopic pregnancy. Prospective study of 478 cases]. / Place de la culdocentèse dans le diagnostic de la grossesse extra-utérine. Etude prospective à propos de 478 cas.

Four hundred and seventy height Culdocenteses were carried out in cases of possible ectopic pregnancy between the 20th September 1986 and 31st December 1987. Culdocentesis was considered to be positive if 2 cm3 or more of dark non-coagulated blood was removed, and negative if only a yellow liquid or blood stained serum was removed. It was not conclusive if nothing could be aspirated or if the blood was coagulated. Of the 94 cases where culdocentesis was positive, 74 were found to have an ectopic pregnancy. There were 20 false positive cases (due to 5 haemorrhagic ruptures of follicles, 3 refluxes of menstrual blood, 2 with other aetiology, and 10 without known cause). There were 21 cases of ectopic pregnancy in the 293 cases where culdocentesis was non-conclusive. Of the 91 cases where culdocentesis was negative, a second culdocentesis showed an ectopic pregnancy. It was positive 11 days after the first. In our series this diagnostic test was reliable in 77.1% of cases. Laparotomy was carried out in 22.3% of cases and only 18.6% had to have laparoscopy thanks to the use of culdocentesis.

[Hoffmann-Zurhelle superficial cutaneous lipomatous nevus. Apropos of a case]. / Le naevus lipomateux cutané superficiel d'Hoffmann et Zurhelle. A propos d'une observation.

The authors report a case of lipomatous naevus present for 35 years, and therefore probably congenital, in a 48 year old female patient. This bulging lesion was 2.5 cm in diameter with a slightly encephaloid appearance. The authors reviewed the limited literature on the subject in order to more clearly define this hamartomatous lesion which has a constant histological appearance, but very variable clinical and macroscopic features.

The occurrence of long ribosomal transcripts homologous to type I insertions in bobbed mutants of Drosophila melanogaster.

In Drosophila melanogaster up to two thirds of the rDNA genes contain insertion sequences of two types in the 28S coding region. Comparison of the ribosomal insertion transcripts in the wild type and in two bobbed mutants reared at two temperatures showed that the level of type I transcripts is dependent on both the number of genes with type I insertions in the bobbed loci and the intensity of bobbed phenotype. Importantly, a long transcript of 8.7 kb hybridized to the ribosomal probe, the INS I probe and also to the restriction fragment of the rDNA downstream of the point of insertion was found in one bobbed mutant. This result and also those from sandwich hybridization indicate that some interrupted ribosomal genes are functional.

[Vesico-uterine fistula. Apropos of 5 cases]. / Les fistules vésico-utérines. A propos de cinq cas.

Five cases of VUF have been observed by the authors over a period of 15 years, reflecting the rarity of this condition. Based on a review of the literature, the authors present an exhaustive study of the various aspects of VUF: 1) aetiopathogenic features: they emphasise the rarity of the disease and its aetiology which is currently dominated by caesarean section; 2) clinical features with little variability in the symptoms (urine leak from the vagina with or without associated menouria) and the usually simple diagnosis based on a thorough clinical examination and routine complementary investigations (IVP, cystography...); 3) lastly the therapeutic aspects, based on surgical cure, which is almost always satisfactory. On the basis of their experience and their results, VUF constitutes a benign lesion, but a source of discomfort, which should be prevented.

[Anatamo-pathological aspects of malignant ovarian tumors in children. Apropos of 16 cases]. / Aspects anatomo-pathologiques des tumeurs malignes de l'ovaire chez l'enfant. A propos de 16 cas.

The authors present 16 cases of malignant ovarian tumors in childhood, censed in Pasteur Institute - Tunis. These tumors are scarce, and present in the literature only 3% of the malignant tumors in childhood. In this series, germ cell tumors are the most frequent and present 81.25% of these cases, of which 43.75% of dysgerminoma. Gonadal stromal tumors are more scarce (6.25%). The prognosis of these tumors was transformed by the radiation therapy in dysgerminoma, and the chemotherapy in the other germ cell tumors. These tumors must be diagnosed and treated early.