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Genetic differentiation among Greek lake populations of Carassius gibelio and Cyprinus carpio carpio
The genetic structure of the Western Greece lake populations of Carassius gibelio and Cyprinus carpio carpio populations was characterized by using a PCR-based RFLP and sequencing analysis of mitochondrial rDNA genes and regions (16S
rDNA, cytochrome b and D-loop). Our analysis was able to detect: (a) two haplotypes in C. c. carpio populations and two haplotypes in C. gibelio populations (b) a high nucleotide divergence between the two species and (c) two genetically distinct C. gibelio populations, one existing in the Amvrakia habitat (AMV1) with a second in Ozeros and Trichonida (OZE1 and TRI1) habitat.
The present analysis indicates that genetic diversity observed was limited with a haplotype index between 0.0 and 55.6%, and
a nucleotide diversity within and among populations between 0.0 and 1.27%. It also underlines a restricted mtDNA-based evaluation
of the phylogenetic relationships among C. gibelio and C. c. carpio populations. In addition, the present study contributed knowledge on the genetic variation and structure of these populations
which is absolutely necessary for any efficient fish management and/or conservation programme. 相似文献
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Rivas LA Mansfield J Tsiamis G Jackson RW Murillo J 《Applied and environmental microbiology》2005,71(7):3778-3785
Virulence for bean and soybean is determined by effector genes in a plasmid-borne pathogenicity island (PAI) in race 7 strain 1449B of Pseudomonas syringae pv. phaseolicola. One of the effector genes, avrPphF, confers either pathogenicity, virulence, or avirulence depending on the plant host and is absent from races 2, 3, 4, 6, and 8 of this pathogen. Analysis of cosmid clones and comparison of DNA sequences showed that the absence of avrPphF from strain 1448A is due to deletion of a continuous 9.5-kb fragment. The remainder of the PAI is well conserved in strains 1448A and 1449B. The left junction of the deleted region consists of a chimeric transposable element generated from the fusion of homologs of IS1492 from Pseudomonas putida and IS1090 from Ralstonia eutropha. The borders of the deletion were conserved in 66 P. syringae pv. phaseolicola strains isolated in different countries and representing the five races lacking avrPphF. However, six strains isolated in Spain had a 10.5-kb deletion that extended 1 kb further from the right junction. The perfect conservation of the 28-nucleotide right repeat of the IS1090 homolog in the two deletion types and in the other 47 insertions of the IS1090 homolog in the 1448A genome strongly suggests that the avrPphF deletions were mediated by the activity of the chimeric mobile element. Our data strongly support a clonal origin for the races of P. syringae pv. phaseolicola lacking avrPphF. 相似文献
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Detection and Characterization of Wolbachia Infections in Natural Populations of Aphids: Is the Hidden Diversity Fully Unraveled? 总被引:1,自引:0,他引:1
Augustinos AA Santos-Garcia D Dionyssopoulou E Moreira M Papapanagiotou A Scarvelakis M Doudoumis V Ramos S Aguiar AF Borges PA Khadem M Latorre A Tsiamis G Bourtzis K 《PloS one》2011,6(12):e28695
Aphids are a serious threat to agriculture, despite being a rather small group of insects. The about 4,000 species worldwide engage in highly interesting and complex relationships with their microbial fauna. One of the key symbionts in arthropods is Wolbachia, an α-Proteobacterium implicated in many important biological processes and believed to be a potential tool for biological control. Aphids were thought not to harbour Wolbachia; however, current data suggest that its presence in aphids has been missed, probably due to the low titre of the infection and/or to the high divergence of the Wolbachia strains of aphids. The goal of the present study is to map the Wolbachia infection status of natural aphids populations, along with the characterization of the detected Wolbachia strains. Out of 425 samples from Spain, Portugal, Greece, Israel and Iran, 37 were found to be infected. Our results, based mainly on 16S rRNA gene sequencing, indicate the presence of two new Wolbachia supergroups prevailing in aphids, along with some strains belonging either to supergroup B or to supergroup A. 相似文献
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Assessing global range expansion in a cryptic species complex: insights from the red seaweed genus Asparagopsis (Florideophyceae) 下载免费PDF全文
Marianela Zanolla María Altamirano Raquel Carmona Julio De la Rosa Virginia Souza‐Egipsy Alison Sherwood Konstantinos Tsiamis Ana Márcia Barbosa Antonio Román Muñoz Nikos Andreakis 《Journal of phycology》2018,54(1):12-24
The mitochondrial genetic diversity, distribution and invasive potential of multiple cryptic operational taxonomic units (OTUs) of the red invasive seaweed Asparagopsis were assessed by studying introduced Mediterranean and Hawaiian populations. Invasive behavior of each Asparagopsis OTU was inferred from phylogeographic reconstructions, past historical demographic dynamics, recent range expansion assessments and future distributional predictions obtained from demographic models. Genealogical networks resolved Asparagopsis gametophytes and tetrasporophytes into four A. taxiformis and one A. armata cryptic OTUs. Falkenbergia isolates of A. taxiformis L3 were recovered for the first time in the western Mediterranean Sea and represent a new introduction for this area. Neutrality statistics supported past range expansion for A. taxiformis L1 and L2 in Hawaii. On the other hand, extreme geographic expansion and an increase in effective population size were found only for A. taxiformis L2 in the western Mediterranean Sea. Distribution models predicted shifts of the climatically suitable areas and population expansion for A. armata L1 and A. taxiformis L1 and L2. Our integrated study confirms a high invasive risk for A. taxiformis L1 and L2 in temperate and tropical areas. Despite the differences in predictions among modelling approaches, a number of regions were identified as zones with high invasion risk for A. taxiformis L2. Since range shifts are likely climate‐driven phenomena, future invasive behavior cannot be excluded for the rest of the lineages. 相似文献
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Although chemotherapy with procarbazine, lomustine and vincristine (PCV) is considered to be well tolerated, side effects
frequently lead to dose reduction or even discontinuation of treatment of oligodendroglial brain tumors. The primary objective
of the analysis was to retrospectively compare progression-free survival (PFS) after PCV vs. PC chemotherapy (without vincristine
to avoid side effects). Patients were retrospectively identified from a database containing our patients between 1990 and
2003. For the selected cases, all histopathology reports were re-evaluated by a local neuropathologist. Based on the updated
histology data, patients were included in the study if they had at least one histological diagnosis of an oligodendroglial
tumor. PFS after start of PCV (n = 61) and PC (n = 84) chemotherapy identical (median 30 months). Multivariate analysis adjusting
for prognostic imbalances favouring the PC group showed a minor, statistically non-significant benefit for PCV (hazard ratio
0.81, 95% confidence interval 0.53–1.25; p = 0.346). Younger age (< 50 y) was a statistically significant predictor of longer
PFS. Significant advantages in terms of overall survival after first diagnosis of oligodendroglial tumor (OS, n = 315) were
found for patients < 50 y (p < 0.001), oligodendrogliomas versus oligoastrocytomas (p = 0.002), and WHO°II vs. °III (p < 0.001).
Three risk groups regarding OS were identified. Findings support the hypothesis that PC may be as effective as PCV chemotherapy,
while avoiding the additonal risks of vincristine. Younger age, lower tumor grade and histology of an oligodendroglioma were
identified to be favorable prognostic factors. 相似文献
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Natália H Mendes Fernando AF Melo Adolfo CB Santos José RC Pandolfi Elisabete A Almeida Rosilene F Cardoso Henri Berghs Suzana David Faber K Johansen Lívia G Espanha Sergio RA Leite Clarice QF Leite 《BMC research notes》2011,4(1):269