scholarly journals Virulence and Pathogenicity Properties of Aggregatibacter actinomycetemcomitans

Pathogens ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 222 ◽  
Author(s):  
Belibasakis ◽  
Maula ◽  
Bao ◽  
Lindholm ◽  
Bostanci ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Cell Death ◽  
Oral Cavity ◽  
Human Population ◽  
Geographic Origin ◽  
Aggregatibacter Actinomycetemcomitans ◽  
Periodontal Pathogen ◽  
The Individual ◽  
Highly Virulent ◽  
Oral Condition

Aggregatibacter actinomycetemcomitans is a periodontal pathogen colonizing the oral cavity of a large proportion of the human population. It is equipped with several potent virulence factors that can cause cell death and induce or evade inflammation. Because of the large genetic diversity within the species, both harmless and highly virulent genotypes of the bacterium have emerged. The oral condition and age, as well as the geographic origin of the individual, influence the risk to be colonized by a virulent genotype of the bacterium. In the present review, the virulence and pathogenicity properties of A. actinomycetemcomitans will be addressed.

scholarly journals Editorial Comments to the Special Issue: “Aggregatibacter actinomycetemcomitans—Gram-Negative Bacterial Pathogen”

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 441
Author(s):  
Jan Oscarsson ◽  
Joseph DiRienzo ◽  
Anders Johansson
Keyword(s):  
Geographic Origin ◽  
Bacterial Pathogen ◽  
Aggregatibacter Actinomycetemcomitans ◽  
Periodontal Pathogen ◽  
Special Issue ◽  
The Individual ◽  
Host Inflammatory Response ◽  
Highly Virulent ◽  
Oral Condition ◽  
Virulence Properties

Aggregatibacter actinomycetemcomitans is a periodontal pathogen colonizing the oral cavity in many individuals of the human population. It is equipped with several potent virulence factors that can cause cell death and induce or evade the host inflammatory response. Both harmless and highly virulent genotypes of the bacterium have emerged because of the large genetic diversity within the species. The oral condition and age, as well as the geographic origin of the individual, influence the risk to be colonized by a virulent genotype of the bacterium. In the present editorial, the different genetic and virulence properties of A. actinomycetemcomitans will be addressed in relation to the publications in this Special Issue.

scholarly journals (274) Genetic Diversity of Wild Pyrus communis L.

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1035D-1036
Author(s):  
Gayle Volk ◽  
Christopher Richards ◽  
Adam Henk ◽  
Ann Reilley ◽  
Nahla Bassil ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Geographic Origin ◽  
Pyrus Communis ◽  
Wild Relatives ◽  
Eastern European ◽  
The Caucasus ◽  
Pyrus Communis L ◽  
National Plant Germplasm System ◽  
Eastern European Countries ◽  
The Individual

Edible European pears (Pyrus communis sp. communis L.) are thought to be derived from wild relatives native to the Caucasus Mountain region and eastern Europe. We collected genotype, phenotype, and geographic origin data for 145 P. communis individuals derived from seeds collected from wild relatives. These individuals are currently maintained in the USDA–ARS National Plant Germplasm System (NPGS) in Corvallis, Ore. Pear genotypes were obtained using 13 microsatellite markers. A Bayesian clustering method grouped the individual pear genotypes into 12 clusters. The subspecies of pears native to the Caucasus Mountains of Russia, Crimea, and Armenia could be genetically differentiated from the subspecies native to eastern European countries. Pears with large fruit clustered closely together and are most closely related to a group of genotypes that are intermediate to the other groups. Based on the high number of unique alleles and heterozygosity in each of the 12 clusters, we conclude that the genetic diversity of wild P. communis is not fully represented in the NPGS

Genetic diversity in Bambara groundnut (Vigna subterranea L.) germplasm revealed by RAPD markers

Genome ◽  
2001 ◽  
Vol 44 (6) ◽  
pp. 995-999 ◽  
Author(s):  
H I Amadou ◽  
P J Bebeli ◽  
P J Kaltsikes
Keyword(s):  
Genetic Diversity ◽  
Cluster Analysis ◽  
Rapd Markers ◽  
Random Amplified Polymorphic Dna ◽  
Geographic Origin ◽  
Bambara Groundnut ◽  
International Institute ◽  
Tropical Agriculture ◽  
Vigna Subterranea ◽  
Ibadan Nigeria

Random amplified polymorphic DNA (RAPD) markers were used to assess genetic diversity in Bambara groundnut (Vigna subterranea L.) germplasm using 25 African accessions from the collection in the International Institute for Tropical Agriculture, Ibadan, Nigeria. Fifty random decamer primers were screened to assess their ability to detect polymorphism in bambara; 17 of them were selected for this study. Considerable genetic diversity was found among the V. subterranea accessions studied. The relationships among the 25 accessions were studied by cluster analysis. The dendrograms showed two main groups of accessions mainly along the lines of their geographic origin. It is concluded that RAPD can be used for germplasm classification in bambara groundnut and hence for improving this crop.Key words: germplasm, PCR, RAPD, Vigna subterranea.

scholarly journals Limited Genetic Diversity in North American Isolates of Phytophthora erythroseptica Pathogenic to Potato Based on RAPD Analysis

Plant Disease ◽  
2005 ◽  
Vol 89 (4) ◽  
pp. 380-384 ◽  
Author(s):  
Rick D. Peters ◽  
Rod J. Clark ◽  
Albert D. Coffin ◽  
Antony V. Sturz ◽  
David H. Lambert ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
North America ◽  
New Brunswick ◽  
Prince Edward Island ◽  
Random Amplified Polymorphic Dna ◽  
Geographic Origin ◽  
The United States ◽  
Vitro Assay ◽  
Phytophthora Erythroseptica

Pink rot of potato (Solanum tuberosum), caused by Phytophthora erythroseptica, is found wherever potatoes are grown, and in the last decade, it has reemerged as an economically important disease in Canada and the United States. A selection of isolates of P. erythroseptica from major potato-growing regions in North America, namely Prince Edward Island and New Brunswick, Canada, and Maine and Idaho, U.S.A., was assessed for genetic diversity with randomly chosen decanucleotide primers which were used to amplify regions of DNA to reveal polymorphisms among templates (random amplified polymorphic DNA [RAPD]). The isolates varied in their geographic origin as well as in their sensitivity to mefenoxam, as determined by an in vitro assay. In three separate RAPD screens (I, II, and III) with 23 isolates of P. erythroseptica chosen from a larger collection, 1,410, 369, and 316 robust, scorable bands were amplified, respectively. However, among the bands amplified in screens I, II, and III, only 3, 1, and 3 bands, respectively, were polymorphic. When three primers yielding polymorphisms were used to screen 106 isolates from Prince Edward Island and New Brunswick, or a representative collection of 32 isolates from Prince Edward Island, New Brunswick, Maine, and Idaho, no major variation was discovered. RAPD markers were not correlated with geographic origin or mefenoxam sensitivity of the isolates. From an evolutionary standpoint, the absence of genetic diversity among the isolates of P. erythroseptica we examined may be attributable to the relatively recent introduction of a small founding population of the pathogen in North America.

Morphological and genetic variability of Baetis (Rhodobaetis) braaschi Zimmermann, 1980 (Ephemeroptera: Baetidae)

Zootaxa ◽  
2012 ◽  
Vol 3323 (1) ◽  
pp. 27 ◽  
Author(s):  
PAVEL SROKA ◽  
ALEXANDER V. MARTYNOV ◽  
ROMAN J. GODUNKO
Keyword(s):  
Genetic Variability ◽  
Methodological Approach ◽  
Morphological Variability ◽  
Geographic Origin ◽  
Intraspecific Variability ◽  
Morphological Data ◽  
Mtdna Coi ◽  
Geographic Regions ◽  
Coi Sequences ◽  
The Individual

Specimens of Baetis (Rhodobaetis) braaschi Zimmermann, 1980 from the three distant geographic regions (Crimean Pen-insula, Eastern Ukraine and Caucasus) are investigated and compared using a methodological approach combining mor-phological and molecular (partial mtDNA COI sequences) data. Intraspecific variability in several morphologicalcharacters is recognized and described, whereas COI sequences are found to be very uniform. The amount and distributionof the changes of COI sequences do not follow the pattern of morphological variability and/or geographic origin of thespecimens. This indicates that analysis of the changes in the COI sequence can contradict the pattern of morphologicalcharacters commonly used for the discrimination of the individual Rhodobaetis species. As a basis for the future taxonom-ic changes concerning subgenus Rhodobaetis, it is advised (where possible) to critically evaluate both molecular and morphological data.

Landscape genetics in mammals

Mammalia ◽  
2014 ◽  
Vol 78 (2) ◽  
Author(s):  
Claudine Montgelard ◽  
Saliha Zenboudji ◽  
Anne-Laure Ferchaud ◽  
Véronique Arnal ◽  
Bettine Jansen van Vuuren
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Landscape Genetics ◽  
Metapopulation Dynamics ◽  
Local Adaptations ◽  
Future Developments ◽  
Ecological Features ◽  
Genetic Patterns ◽  
The Individual

AbstractThe focus of this review is on landscape genetics (LG), a relatively new discipline that arose approximately 10 years ago. LG spans the interface between population genetics and landscape ecology and thus incorporates the concepts, methods, and tools from both disciplines. On the basis of an understanding of the spatial distribution of genetic diversity, LG aims to explain how landscape and environmental characteristics influence microevolutionary processes and metapopulation dynamics, including gene flow (i.e., connectivity) and selection (i.e., local adaptations). LG is concerned with events that occurred during the recent time scale, and the individual is the operational unit. As a discipline that combines spatial genetic diversity with ecological features, LG is able to address questions relating to different evolutionary processes. We illustrate some of these here using examples taken from mammals: population structure; gene flow and the identification of barriers; fragmentation, connectivity, and corridors; local adaptation and selection; there are two different questions: applications in conservation genetics; and future developments in LG. We will then present the methods and tools commonly used in the different steps of LG analyses: the genetic and landscape sampling, the quantification of genetic variation, the characterization of spatial landscape structures, and finally, the correlation between genetic patterns and landscape features.

scholarly journals Toward Personalized Oral Diagnosis: Distinct Microbiome Clusters in Periodontitis Biofilms

2021 ◽  
Vol 11 ◽  
Author(s):  
Roland Wirth ◽  
Bernadett Pap ◽  
Gergely Maróti ◽  
Péter Vályi ◽  
Laura Komlósi ◽  
...  
Keyword(s):  
Amplicon Sequencing ◽  
Abundant Species ◽  
Periodontal Pathogen ◽  
Host Immune System ◽  
Periodontal Pathogens ◽  
Pocket Depth ◽  
Probing Pocket Depth ◽  
The Individual ◽  
Biofilm Development

Periodontitis is caused by pathogenic subgingival microbial biofilm development and dysbiotic interactions between host and hosted microbes. A thorough characterization of the subgingival biofilms by deep amplicon sequencing of 121 individual periodontitis pockets of nine patients and whole metagenomic analysis of the saliva microbial community of the same subjects were carried out. Two biofilm sampling methods yielded similar microbial compositions. Taxonomic mapping of all biofilms revealed three distinct microbial clusters. Two clinical diagnostic parameters, probing pocket depth (PPD) and clinical attachment level (CAL), correlated with the cluster mapping. The dysbiotic microbiomes were less diverse than the apparently healthy ones of the same subjects. The most abundant periodontal pathogens were also present in the saliva, although in different representations. The single abundant species Tannerella forsythia was found in the diseased pockets in about 16–17-fold in excess relative to the clinically healthy sulcus, making it suitable as an indicator of periodontitis biofilms. The discrete microbial communities indicate strong selection by the host immune system and allow the design of targeted antibiotic treatment selective against the main periodontal pathogen(s) in the individual patients.

scholarly journals Aggregatibacter actinomycetemcomitans: The virulence factors and relation to persistence biofilm formation

Biomedicine ◽  
2021 ◽  
Vol 40 (4) ◽  
pp. 429-435
Author(s):  
Syakir Syahiran ◽  
Wan Rohani Wan Taib ◽  
Norzawani Jaffar
Keyword(s):  
Oral Cavity ◽  
Virulence Factors ◽  
Tooth Loss ◽  
Periodontal Diseases ◽  
Aggregatibacter Actinomycetemcomitans ◽  
Aggressive Periodontitis ◽  
Essential Factor ◽  
Abiotic Surfaces ◽  
Functional Biology ◽  
Systemic Infections

Periodontitis is an infectious and inflammatory condition that is associated with subgingival biofilms in tooth-supporting tissues. Among the several hundred isolated organisms in the oral cavity, one of the most isolated bacteria from infected periodontal pockets are Aggregatibacter actinomycetemcomitans. It is a Gram-negative, facultative anaerobic bacillus that causes juvenile (localized aggressive periodontitis) and adolescent periodontal diseases. The development of biofilms is an essential factor in pathogenesis for A. actinomycetemcomitans. The early attachment of A. actinomycetemcomitans to abiotic surfaces relies on its protein-like fimbriae. This organism's ability to form tenacious biofilms can determine its survival and progression. A. actinomycetemcomitans, a pathogen not solely in periodontal but also involve in some systemic infections. This species has several virulence factors and genes that contribute to its oral cavity survival and, worst of all, cause bone resorption and tooth loss. Genetic diversity between the different A. actinomycetemcomitans isolates are great, and their ability to express and release virulence factors varies. In this review article, we discuss about the potential virulence factors and candidates genes for A. actinomycetemcomitans and their roles within periodontal disease by revealing their functional biology in facilitating attachment to oral surfaces, hindering protection of the host and causing inflammation and degradation of tissue.

Characterization of Pyrenophora tritici-repentis in Tunisia and Comparison with a Global Pathogen Population

Plant Disease ◽  
2021 ◽  
Author(s):  
Marwa Laribi ◽  
Alireza Akhavan ◽  
Sarrah M'Barek ◽  
Amor Yahyaoui ◽  
Stephen Ernest Strelkov ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Geographic Origin ◽  
Tan Spot ◽  
Pcr Analysis ◽  
Group Method ◽  
Region Of Origin ◽  
Pyrenophora Tritici Repentis ◽  
Pair Group ◽  
Necrotrophic Effector

Pyrenophora tritici-repentis (Ptr) causes tan spot, an important foliar disease of wheat. A collection of Ptr isolates from Tunisia, located in one of the main secondary centers of diversification of durum wheat, was tested for phenotypic race classification based on virulence on a host differential set, and for the presence of the necrotrophic effector (NE) genes ToxA, ToxB , and toxb by PCR analysis. While races 2, 4, 5, 6, 7, and 8 were identified according to their virulence phenotypes, PCR testing indicated the presence of ‘atypical’ isolates that induced necrosis on the wheat differential ‘Glenlea’, but lacked the expected ToxA gene, suggesting the involvement of other NEs in the Ptr/wheat interaction. Genetic diversity and the Ptr population structure were explored further by examining 59 Tunisian isolates and 35 isolates from Algeria, Azerbaijan, Canada, Iran, and Syria using 24 simple sequence repeat markers. Average genetic diversity, overall gene flow and percentage polymorphic loci were estimated as 0.58, 2.09 and 87%, respectively. Analysis of molecular variance showed that 81% of the genetic variance occurred within populations and 19% between populations. Cluster analysis by the unweighted pair group method indicated that ToxB- isolates grouped together and were distantly related to ToxB+ isolates. Based on Nei’s analysis, the global collection clustered into two distinct groups according to their region of origin. The results suggest that both geographic origin and the host-specificity imposed by different NEs can lead to differentiation among Ptr populations.

scholarly journals Polymorphism of prolamin proteins of the grain of triticale varieties certifiedin the Czech Republic

2011 ◽  
Vol 51 (No. 4) ◽  
pp. 151-155 ◽  
Author(s):  
T. Vyhnánek ◽  
J. Bednář
Keyword(s):  
Genetic Diversity ◽  
Czech Republic ◽  
Cold Resistance ◽  
The Czech Republic ◽  
Baking Quality ◽  
The Individual

 Genetic diversity was detected in 11 varieties of triticale registered in the Czech Republic by means of polymorphism of prolamin proteins using the PAGE ISTA method. The polymorphism of prolamin proteins allowed the differentiation of the individual triticale varieties in 2002 and 2003 harvests. On the basis of Dice’s calculations of coefficients of similarity we discovered, in parallel with the uniform genotypes, genotypes with sister prolamin spectrums with a different percentage of participation in the respective years. A uniform spectrum was detected in the following varieties: Disco, Kolor, Lamberto, Marko, Presto, Sekundo, Ticino and Tricolor; Kitaro and Modus were dimorphous varieties. In 2003 three sister prolamin lines appeared in the variety Gabo and in 2004 only two. In 2003 a 5% admixture of a foreign genotype was detected in the variety Marko. Typical of the unknown genotype was the gliadin block Gld 1B3, which is the marker of rye translocation T1BL.1RS, gene Sr31 with resistance to black rust, higher cold resistance and lower baking quality of the wheat. The prolamin proteins of triticale grain are suitable for the detection of the genetic diversity and for the assessment of varietal authenticity and purity in seed samples of triticale varieties registered in the Czech Republic.

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