Hybridization and introgression can impact the evolution of natural populations. Several wild canid species hybridize in nature, sometimes originating new taxa. However, hybridization with free-ranging dogs is threatening the genetic integrity of grey wolf populations (Canis lupus), or even the survival of endangered species (e.g., the Ethiopian wolf C. simensis). Efficient molecular tools to assess hybridization rates are essential in wolf conservation strategies. We evaluated the power of biparental and uniparental markers (39 autosomal and 4 Y-linked microsatellites, a melanistic deletion at the β-defensin CBD103 gene, the hypervariable domain of the mtDNA control-region) to identify the multilocus admixture patterns in wolf x dog hybrids. We used empirical data from 2 hybrid groups with different histories: 30 presumptive natural hybrids from Italy and 73 Czechoslovakian wolfdogs of known hybrid origin, as well as simulated data. We assessed the efficiency of various marker combinations and reference samples in admixture analyses using 69 dogs of different breeds and 99 wolves from Italy, Balkans and Carpathian Mountains. Results confirmed the occurrence of hybrids in Italy, some of them showing anomalous phenotypic traits and exogenous mtDNA or Y-chromosome introgression. Hybridization was mostly attributable to village dogs and not strictly patrilineal. The melanistic β-defensin deletion was found only in Italian dogs and in putative hybrids. The 24 most divergent microsatellites (largest wolf-dog FST values) were equally or more informative than the entire panel of 39 loci. A smaller panel of 12 microsatellites increased risks to identify false admixed individuals. The frequency of F1 and F2 was lower than backcrosses or introgressed individuals, suggesting hybridization already occurred some generations in the past, during early phases of wolf expansion from their historical core areas. Empirical and simulated data indicated the identification of the past generation backcrosses is always uncertain, and a larger number of ancestry-informative markers is needed.

• MeSH
• beta-Defensins genetics   MeSH
• Y Chromosome MeSH
• Genetic Variation MeSH
• Genetic Markers * MeSH
• Genotype MeSH
• Hybridization, Genetic * MeSH
• Microsatellite Repeats MeSH
• DNA, Mitochondrial MeSH
• Evolution, Molecular MeSH
• Multilocus Sequence Typing * MeSH
• Genetics, Population MeSH
• Dogs MeSH
• Cluster Analysis MeSH
• Wolves MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Dogs MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Italy MeSH

BACKGROUND: There have been conflicting reports in the literature on association of gene copy number with disease, including CCL3L1 and HIV susceptibility, and β-defensins and Crohn's disease. Quantification of precise gene copy numbers is important in order to define any association of gene copy number with disease. At present, real-time quantitative PCR (QPCR) is the most commonly used method to determine gene copy number, however the Paralogue Ratio Test (PRT) is being used in more and more laboratories. FINDINGS: In this study we compare a Pyrosequencing-based Paralogue Ratio Test (PPRT) for determining beta-defensin gene copy number with two currently used methods for gene copy number determination, QPCR and triplex PRT by typing five different cohorts (UK, Danish, Portuguese, Ghanaian and Czech) of DNA from a total of 576 healthy individuals. We found a systematic measurement bias between DNA cohorts revealed by QPCR, but not by the PRT-based methods. Using PRT, copy number ranged from 2 to 9 copies, with a modal copy number of 4 in all populations. CONCLUSIONS: QPCR is very sensitive to quality of the template DNA, generating systematic biases that could produce false-positive or negative disease associations. Both triplex PRT and PPRT do not show this systematic bias, and type copy number within the correct range, although triplex PRT appears to be a more precise and accurate method to type beta-defensin copy number.

• MeSH
• beta-Defensins genetics   MeSH
• Genetic Predisposition to Disease MeSH
• Genome, Human genetics   MeSH
• Gene Dosage * MeSH
• Cohort Studies MeSH
• Humans MeSH
• Chromosome Mapping methods   MeSH
• Molecular Sequence Data MeSH
• Population MeSH
• Genetics, Population methods   MeSH
• Base Sequence MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH
• Geographicals
• Czech Republic MeSH
• Denmark MeSH
• Ghana MeSH
• Portugal MeSH
• United Kingdom MeSH

Defensiny jsou antimikrobiální a imunomodulační peptidy, které jsou důležitou součástí přirozené imunity. Autoři stručně charakterizují přirozenou imunitu, chemickou stavbu a funkci defensinů. Zabývají se především lidskými defensiny na respiračních sliznicích a jejich účinkem na bakterie, a to hlavně na grampozitivní bakterii Staphylococcus aureus. Defensiny mají přímý destrukční účinek na bakteriální stěnu, ale mají i imunomodulační účinek. Lidské defensiny dělíme podle struktury na alfa a beta 1, beta 2, beta 3 a beta 4. Alfa jsou v granulocytech, ve sliznici urogenitálního a intestinálního traktu. Beta defensiny jsou ve všech epiteliálních tkáních. V epitelu dýchacích cest jsou beta defensiny 1 produkovány konstitučně a beta defensiny 2 a 3 jsou indukovány jako odpověď na infekční agens. Některé bakterie mohou modifikovat svoji stěnu tak, aby byly méně citlivé na defensiny. U bakterie Staphylococcus aureus byly zjištěny geny Dlt a MprF, které jsou zodpovědné za modifikaci kyseliny teichoové a phosphatidylglycerolu v membráně takovým způsobem, že se sníží atraktivita bakterie pro pozitivně nabité defensiny. Poruchy těchto genů způsobují zvýšenou senzitivitu této bakterie na defensiny. Nové poznatky o antimikrobiálních peptidech nám umožňují lépe rozumět infekčním onemocněním a nabízejí nové perspektivy v terapii těchto onemocnění.

Defensins are antimicrobial and immunomodulation peptides, which are the important part of natural immunity. The authors briefly characterize natural immunity, chemical structure and function of defensins. The review deals preferentially with human defensins on respiratory mucous membranes and their effects on bacteria, mainly on gram-negative Staphylococcus aureus. Defensins exert a direct destructive effect on bacterial wall, but they possess an immunomodulation effect as well. Human defensins are divided according to their structure to alpha, beta 1, beta 2, beta 3 and beta 4. Alpha defensins are in granulocytes, in mucosa of urogenital and intestinal tract. Beta defensins are in all epithelial tissues. In the epithelium of respiratory pathways beta defensins 1 are produced constitutively and beta defensins 2 and 3 are induced as a response to infection agents. Some bacteria can modify their wall and thereby become less sensitive to defensins. In the bacteria Staphylococcus aureus the genes Dlt and Mrpf were found responsible for modification of teichoic acid and phosphatidylglycerol in the membrane in such a way that it decreases attractiveness of the bacteria for the positively charged defensins. Defects in these genes caused increased sensitivity of this bacterium to defensins. New knowledge of antibacterial peptides helps us to understand better infectious diseases and offers new perspectives in the therapy of these diseases.

• MeSH
• alpha-Defensins genetics   immunology   classification   MeSH
• beta-Defensins genetics   immunology   classification   MeSH
• Defensins immunology   classification   therapeutic use   MeSH
• Financing, Organized MeSH
• Immunologic Factors genetics   immunology   MeSH
• Antimicrobial Cationic Peptides genetics   immunology   MeSH
• Humans MeSH
• Airway Resistance physiology   genetics   immunology   MeSH
• Staphylococcus aureus genetics   immunology   MeSH
• Check Tag
• Humans MeSH

Studies of the human defensins have been hampered by the lack of a simple expression system allowing for rapid production of functional peptide forms. Here, we describe a Saccharomyces cerevisiae AH22 expression system that meets that condition. The 42 amino acid form of human beta-defensin-1 was expressed under the control of the ADH1 promoter. The optimum conditions for expression were determined and the stable maintenance of the pVT103L-hBD-1 chimeric vector in the yeast population was confirmed. Expressed hBD-1 was secreted into the medium (approximately 55 microg l(-1)) and purified using cation-exchange chromatography. Isolated defensin exhibited strong bactericidal effect on Escherichia coli ML-35p. We conclude that the expression system described here will be a useful tool where readily prepared and active forms of the human defensins are needed.

• MeSH
• Anti-Bacterial Agents biosynthesis   pharmacology   isolation & purification   MeSH
• beta-Defensins biosynthesis   pharmacology   genetics   chemistry   MeSH
• Escherichia coli cytology   drug effects   MeSH
• Genetic Vectors genetics   MeSH
• Humans MeSH
• Molecular Sequence Data MeSH
• Cell Proliferation drug effects   MeSH
• Recombinant Proteins biosynthesis   pharmacology   chemistry   isolation & purification   MeSH
• Saccharomyces cerevisiae genetics   MeSH
• Amino Acid Sequence MeSH
• Check Tag
• Humans MeSH