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Everest GJ,
Meyers PR,
( 2009 ) The use of gyrB sequence analysis in the phylogeny of the genus Amycolatopsis. PMID : 18803029 : DOI : 10.1007/s10482-008-9280-9 Abstract >>
Partial gyrB sequences (>1 kb) were obtained from 34 type strains of the genus Amycolatopsis. Phylogenetic trees were constructed to determine the effectiveness of using this gene to predict taxonomic relationships within the genus. The use of gyrB sequence analysis as an alternative to DNA-DNA hybridization was also assessed for distinguishing closely related species. The gyrB based phylogeny mostly confirmed the conventional 16S rRNA gene-based phylogeny and thus provides additional support for certain of these 16S rRNA gene-based phylogenetic groupings. Although pairwise gyrB sequence similarity cannot be used to predict the DNA relatedness between type strains, the gyrB genetic distance can be used as a means to assess quickly whether an isolate is likely to represent a new species in the genus Amycolatopsis. In particular a genetic distance of >0.02 between two Amycolatopsis strains (based on a 315 bp variable region of the gyrB gene) is proposed to provide a good indication that they belong to different species (and that polyphasic taxonomic characterization of the unknown strain is worth undertaking).
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2. |
Everest GJ,
Meyers PR,
( 2011 ) Evaluation of the antibiotic biosynthetic potential of the genus Amycolatopsis and description of Amycolatopsis circi sp. nov., Amycolatopsis equina sp. nov. and Amycolatopsis hippodromi sp. nov. PMID : 21615633 : DOI : 10.1111/j.1365-2672.2011.05058.x Abstract >>
To describe three new Amycolatopsis strains and assess the antibiotic biosynthetic potential of the genus. Three strains, designated S1�P3(T) , S3�P6(T) and SE(8)3(T) , belonging to the genus Amycolatopsis were isolated and found to cluster together by 16S rRNA and gyrB gene-based phylogenetic analysis. Genetic distance values, based on the gyrB gene, were calculated between the strains and their closest relatives and were all above the threshold value of 0�P02 that has been proposed to distinguish Amycolatopsis type strains. DNA-DNA hybridization experiments against related type strains confirmed that strain S3�P6(T) represents a unique genomic species. Strain S3�P6(T) was also found to be distinct from strains S1�P3(T) and SE(8)3(T) , the latter two of which were also shown to be distinct from each other. Antibiotic biosynthetic genes were identified from multiple Amycolatopsis strains, and their presence was found to be phylogenetically associated. The data presented in this study indicate that strains S1�P3(T) , SE(8)3(T) and S3�P6(T) belong to three novel species, for which the names Amycolatopsis circi sp. nov. (= DSM 45561(T) = NRRL B-24841(T)), Amycolatopsis equina sp. nov. (= DSM 45563(T) = NRRL B-24842(T)) and Amycolatopsis hippodromi sp. nov. (= DSM 45562(T) = NRRL B-24843(T)) are proposed. Three new species of Amycolatopsis are described, and the knowledge of the antibiotic biosynthetic potential of the genus has been extended.
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3. |
Radwan SS,
Al-Mailem DM,
Kansour MK,
( 2017 ) Calcium (II) - and dipicolinic acid mediated-biostimulation of oil-bioremediation under multiple stresses by heat, oil and heavy metals. PMID : 28842661 : DOI : 10.1038/s41598-017-10121-7 PMC : PMC5573387 Abstract >>
The oil-producing Arabian Gulf states have hot summer seasons of about 7-month in length. Therefore, environmental oil spills should be bioremediated by the activity of indigenous, hydrocarbonoclastic (hydrocarbon-degrading) microorganisms with optimum growth at about 50 �XC. Soils in such arid countries harbor thermophilic bacteria, whose oil-consumption potential is enhanced by calcium (II) - and dipicolinic acid (DPA)-supplement. Those organisms are, however, subjected to additional stresses including toxic effects of heavy metals that may be associated with the spilled oil. Our study highlighted the resistance of indigenous, thermophilic isolates to the heavy metals, mercury (II), cadmium (II), arsenic (II) and lead (II) at 50 �XC. We also detected the uptake of heavy metals by 15 isolates at 50 �XC, and identified the merA genes coding for Hg2+-resistance in 4 of the studied Hg2+-resistant isolates. Hg2+ was the most toxic metal and the metal toxicity was commonly higher in the presence of oil. The addition of Ca2+ and DPA enhanced the Hg2+-resistance among most of the isolates at 50 �XC. Crude oil consumption at 50 �XC by 4 selected isolates was inhibited by the tested heavy metals. However, Ca2+ and DPA limited this inhibition and enhanced oil-consumption, which exceeded by far the values in the control cultures.
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