scholarly journals Cautionary tale of using 16S rRNA gene sequence similarity values in identification of human-associated bacterial species

2015 ◽  
Vol 65 (Pt_6) ◽  
pp. 1929-1934 ◽  
Author(s):  
Morgane Rossi-Tamisier ◽  
Samia Benamar ◽  
Didier Raoult ◽  
Pierre-Edouard Fournier
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Gene Sequence ◽  
Sequence Similarity ◽  
Bacterial Species ◽  
16S Rrna Gene Sequence ◽  
Rrna Gene ◽  
Rrna Gene Sequence ◽  
Bacterial Taxonomy ◽  
Associated Species

Modern bacterial taxonomy is based on a polyphasic approach that combines phenotypic and genotypic characteristics, including 16S rRNA sequence similarity. However, the 95 % (for genus) and 98.7 % (for species) sequence similarity thresholds that are currently recommended to classify bacterial isolates were defined by comparison of a limited number of bacterial species, and may not apply to many genera that contain human-associated species. For each of 158 bacterial genera containing human-associated species, we computed pairwise sequence similarities between all species that have names with standing in nomenclature and then analysed the results, considering as abnormal any similarity value lower than 95 % or greater than 98.7 %. Many of the current bacterial species with validly published names do not respect the 95 and 98.7 % thresholds, with 57.1 % of species exhibiting 16S rRNA gene sequence similarity rates ≥98.7 %, and 60.1 % of genera containing species exhibiting a 16S rRNA gene sequence similarity rate <95 %. In only 17 of the 158 genera studied (10.8 %), all species respected the 95 and 98.7 % thresholds. As we need powerful and reliable taxonomical tools, and as potential new tools such as pan-genomics have not yet been fully evaluated for taxonomic purposes, we propose to use as thresholds, genus by genus, the minimum and maximum similarity values observed among species.

scholarly journals Microvirga Jeongseonensis Sp. Nov., New Species Isolated From Soil in South Korea

2021 ◽  
Author(s):  
Soohyun Maeng ◽  
Yuna Park ◽  
Hyejin Oh ◽  
Minji Bang ◽  
Jigden Baigalmaa ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
South Korea ◽  
Gene Sequence ◽  
Sequence Similarity ◽  
Bacterial Species ◽  
16S Rrna Gene Sequence ◽  
Rrna Gene ◽  
Rrna Gene Sequence ◽  
Respiratory Quinone

Abstract A novel Gram-stain-negative, aerobic, rod-shaped, convex, and light pink-colored strain BT688T was isolated from a soil sample collected in Jeongseon city, South Korea. Phylogenetic analysis based on 16S rRNA gene sequence revealed that strain BT688T belongs to a distinct lineage within the genus Microvirga (family Methylobacteriaceae, order Rhizobiales, class Alpha Proteobacteria, phylum Proteobacteria). The 16S rRNA gene sequence similarity between strain BT688T and Microvirga aerilata 5420S-16T was 98.5%. Strain BT688T had Q-10 as a major respiratory quinone and the major polar lipids of strain BT688T was diphosphatidilglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), and phosphatidylcholine (PC). The major cellular fatty acids of strain BT688T were C18:1 ω7c (76.0%) and summed feature 3 (9.6%).Based on the polyphasic characteristics, strain BT688T can be suggested as a novel bacterial species within the genus Microvirga and the proposed name is Microvirga jeongseonensis. The type strain of Microvirga jeongseonensis is BT688T (= KCTC XXXXT=NBRC 114857 T).

scholarly journals Ohtaekwangia koreensis gen. nov., sp. nov. and Ohtaekwangia kribbensis sp. nov., isolated from marine sand, deep-branching members of the phylum Bacteroidetes

2011 ◽  
Vol 61 (5) ◽  
pp. 1066-1072 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
So-Jung Kang ◽  
Soo-Young Lee ◽  
Jung-Sook Lee ◽  
Sooyeon Park
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Type Strain ◽  
Gene Sequence ◽  
Sequence Similarity ◽  
Bacterial Species ◽  
16S Rrna Gene Sequence ◽  
Rrna Gene ◽  
Sand Sample ◽  
Rrna Gene Sequence

Two Gram-stain-negative, non-motile, non-spore-forming, rod-shaped bacterial strains, designated 3B-2T and 10AOT, were isolated from a sand sample collected from the west coast of the Korean peninsula by using low-nutrient media, and their taxonomic positions were investigated in a polyphasic study. The strains did not grow on marine agar. They grew optimally at 30 °C and pH 6.5–7.5. Strains 3B-2T and 10AOT shared 97.5 % 16S rRNA gene sequence similarity and mean level of DNA–DNA relatedness of 12 %. In phylogenetic trees based on 16S rRNA gene sequences, strains 3B-2T and 10AOT, together with several uncultured bacterial clones, formed independent lineages within the evolutionary radiation encompassed by the phylum Bacteroidetes. Strains 3B-2T and 10AOT contained MK-7 as the predominant menaquinone and iso-C15 : 0 and C16 : 1ω5c as the major fatty acids. The DNA G+C contents of strains 3B-2T and 10AOT were 42.8 and 44.6 mol%, respectively. Strains 3B-2T and 10AOT exhibited very low levels of 16S rRNA gene sequence similarity (<85.0 %) to the type strains of recognized bacterial species. These data were sufficient to support the proposal that the novel strains should be differentiated from previously known genera of the phylum Bacteroidetes. On the basis of the data presented, we suggest that strains 3B-2T and 10AOT represent two distinct novel species of a new genus, for which the names Ohtaekwangia koreensis gen. nov., sp. nov. (the type species; type strain 3B-2T  = KCTC 23018T  = CCUG 58939T) and Ohtaekwangia kribbensis sp. nov. (type strain 10AOT  = KCTC 23019T  = CCUG 58938T) are proposed.

scholarly journals Streptomonospora litoralis sp. nov., a halophilic thiopeptides producer isolated from sand collected at Cuxhaven beach

2021 ◽  
Author(s):  
Shadi Khodamoradi ◽  
Richard L. Hahnke ◽  
Yvonne Mast ◽  
Peter Schumann ◽  
Peter Kämpfer ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Gene Sequence ◽  
Sequence Similarity ◽  
Bioinformatic Analysis ◽  
Biosynthetic Gene Cluster ◽  
16S Rrna Gene Sequence ◽  
Rrna Gene ◽  
Rrna Gene Sequence ◽  
Polar Lipid Profile

AbstractStrain M2T was isolated from the beach of Cuxhaven, Wadden Sea, Germany, in course of a program to attain new producers of bioactive natural products. Strain M2T produces litoralimycin and sulfomycin-type thiopeptides. Bioinformatic analysis revealed a potential biosynthetic gene cluster encoding for the M2T thiopeptides. The strain is Gram-stain-positive, rod shaped, non-motile, spore forming, showing a yellow colony color and forms extensively branched substrate mycelium and aerial hyphae. Inferred from the 16S rRNA gene phylogeny strain M2T affiliates with the genus Streptomonospora. It shows 96.6% 16S rRNA gene sequence similarity to the type species Streptomonospora salina DSM 44593 T and forms a distinct branch with Streptomonospora sediminis DSM 45723 T with 97.0% 16S rRNA gene sequence similarity. Genome-based phylogenetic analysis revealed that M2T is closely related to Streptomonospora alba YIM 90003 T with a digital DNA-DNA hybridisation (dDDH) value of 26.6%. The predominant menaquinones of M2T are MK-10(H6), MK-10(H8), and MK-11(H6) (> 10%). Major cellular fatty acids are iso-C16:0, anteiso C17:0 and C18:0 10-methyl. The polar lipid profile consisted of diphosphatidylglycerol phosphatidyl glycerol, phosphatidylinositol, phosphatidylcholine, phosphatidylethanolamine, three glycolipids, two unknown phospholipids, and two unknown lipids. The genome size of type strain M2T is 5,878,427 bp with 72.1 mol % G + C content. Based on the results obtained from phylogenetic and chemotaxonomic studies, strain M2T (= DSM 106425 T = NCCB 100650 T) is considered to represent a novel species within the genus Streptomonospora for which the name Streptomonospora litoralis sp. nov. is proposed.

scholarly journals Faecalicoccus acidiformans gen. nov., sp. nov., isolated from the chicken caecum, and reclassification of Streptococcus pleomorphus (Barnes et al. 1977), Eubacterium biforme (Eggerth 1935) and Eubacterium cylindroides (Cato et al. 1974) as Faecalicoccus pleomorphus comb. nov., Holdemanella biformis gen. nov., comb. nov. and Faecalitalea cylindroides gen. nov., comb. nov., respectively, within the family Erysipelotrichaceae

2014 ◽  
Vol 64 (Pt_11) ◽  
pp. 3877-3884 ◽  
Author(s):  
Celine De Maesschalck ◽  
Filip Van Immerseel ◽  
Venessa Eeckhaut ◽  
Siegrid De Baere ◽  
Margo Cnockaert ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Type Species ◽  
Gene Sequence ◽  
Sequence Similarity ◽  
16S Rrna Gene Sequence ◽  
Rrna Gene ◽  
Rrna Gene Sequence ◽  
Content Type ◽  
Link Type

Strains LMG 27428T and LMG 27427 were isolated from the caecal content of a chicken and produced butyric, lactic and formic acids as major metabolic end products. The genomic DNA G+C contents of strains LMG 27428T and LMG 27427 were 40.4 and 38.8 mol%. On the basis of 16S rRNA gene sequence similarity, both strains were most closely related to the generically misclassified Streptococcus pleomorphus ATCC 29734T. Strain LMG 27428T could be distinguished from S. pleomorphus ATCC 29734T based on production of more lactic acid and less formic acid in M2GSC medium, a higher DNA G+C content and the absence of activities of acid phosphatase and leucine, arginine, leucyl glycine, pyroglutamic acid, glycine and histidine arylamidases, while strain LMG 27428 was biochemically indistinguishable from S. pleomorphus ATCC 29734T. The novel genus Faecalicoccus gen. nov. within the family Erysipelotrichaceae is proposed to accommodate strains LMG 27428T and LMG 27427. Strain LMG 27428T ( = DSM 26963T) is the type strain of Faecalicoccus acidiformans sp. nov., and strain LMG 27427 ( = DSM 26962) is a strain of Faecalicoccus pleomorphus comb. nov. (type strain LMG 17756T = ATCC 29734T = DSM 20574T). Furthermore, the nearest phylogenetic neighbours of the genus Faecalicoccus are the generically misclassified Eubacterium cylindroides DSM 3983T (94.4 % 16S rRNA gene sequence similarity to strain LMG 27428T) and Eubacterium biforme DSM 3989T (92.7 % 16S rRNA gene sequence similarity to strain LMG 27428T). We present genotypic and phenotypic data that allow the differentiation of each of these taxa and propose to reclassify these generically misnamed species of the genus Eubacterium formally as Faecalitalea cylindroides gen. nov., comb. nov. and Holdemanella biformis gen. nov., comb. nov., respectively. The type strain of Faecalitalea cylindroides is DSM 3983T = ATCC 27803T = JCM 10261T and that of Holdemanella biformis is DSM 3989T = ATCC 27806T = CCUG 28091T.

scholarly journals Paenibacillus xinjiangensis sp. nov., isolated from Xinjiang province in China

2006 ◽  
Vol 56 (11) ◽  
pp. 2579-2582 ◽  
Author(s):  
Jee-Min Lim ◽  
Che Ok Jeon ◽  
Dong-Jin Park ◽  
Li-Hua Xu ◽  
Cheng-Lin Jiang ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Gene Sequence ◽  
Sequence Similarity ◽  
Diaminopimelic Acid ◽  
16S Rrna Gene Sequence ◽  
Rrna Gene ◽  
Rrna Gene Sequence ◽  
16S Rrna Gene Sequences ◽  
Sequence Similarities

Strain B538T is a Gram-positive, motile, rod-shaped bacterium, which was isolated from Xinjiang province in China. This organism grew optimally at 30–35 °C and pH 8.0–8.5. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain B538T belonged to the genus Paenibacillus and chemotaxonomic data (DNA G+C content, 47.0 mol%; major isoprenoid quinone, MK-7; cell wall type, A1γ meso-diaminopimelic acid; major fatty acids, anteiso-C15 : 0 and C16 : 0) supported affiliation of the isolate with the genus Paenibacillus. Comparative 16S rRNA gene sequence analyses showed that the isolate was most closely related to Paenibacillus glycanilyticus DS-1T, with 16S rRNA gene sequence similarity of 98.1 %; sequence similarities to other members of the genus Paenibacillus used in the phylogenetic tree were less than 96.5 %. The DNA–DNA relatedness between strain B538T and P. glycanilyticus DS-1T was about 8.0 %. On the basis of physiological and molecular properties, strain B538T (=KCTC 3952T=DSM 16970T) is proposed as the type strain of a novel species within the genus Paenibacillus, for which the name Paenibacillus xinjiangensis sp. nov. is proposed.

scholarly journals Exiguobacterium aestuarii sp. nov. and Exiguobacterium marinum sp. nov., isolated from a tidal flat of the Yellow Sea in Korea

2005 ◽  
Vol 55 (2) ◽  
pp. 885-889 ◽  
Author(s):  
In-Gi Kim ◽  
Mi-Hwa Lee ◽  
Seo-Youn Jung ◽  
Jae Jun Song ◽  
Tae-Kwang Oh ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Tidal Flat ◽  
Yellow Sea ◽  
Type Strain ◽  
Gene Sequence ◽  
Sequence Similarity ◽  
16S Rrna Gene Sequence ◽  
Rrna Gene ◽  
Rrna Gene Sequence

Three Gram-variable, rod-shaped bacterial strains, TF-16T, TF-19 and TF-80T, were isolated from a tidal flat of Daepo Beach (Yellow Sea) near Mokpo City, Korea, and their taxonomic positions were investigated by a polyphasic approach. These isolates grew optimally in the presence of 2 % NaCl and at 30 °C. Their peptidoglycan types were based on l-Lys–Gly. The predominant menaquinone detected in the three strains was MK-7. The three strains contained large amounts of the branched fatty acids iso-C17 : 0, anteiso-C13 : 0, iso-C13 : 0 and iso-C15 : 0. The DNA G+C contents of strains TF-16T, TF-19 and TF-80T were 48·6, 48·4 and 48·0 mol%, respectively. The three strains formed a coherent cluster with Exiguobacterium species in a phylogenetic tree based on 16S rRNA gene sequences. They showed closest phylogenetic affiliation to Exiguobacterium aurantiacum, with 16S rRNA gene sequence similarity values of 98·1–98·3 %. The three strains exhibited 16S rRNA gene sequence similarity values of 94·0–94·6 % to the type strains of other Exiguobacterium species. Levels of DNA–DNA relatedness indicated that strains TF-16T and TF-19 and strain TF-80T are members of two species that are separate from E. aurantiacum. On the basis of phenotypic, phylogenetic and genetic data, strains TF-16T and TF-19 and strain TF-80T represent two novel species in the genus Exiguobacterium; the names Exiguobacterium aestuarii sp. nov. (type strain TF-16T=KCTC 19035T=DSM 16306T; reference strain TF-19) and Exiguobacterium marinum sp. nov. (type strain TF-80T=KCTC 19036T=DSM 16307T) are proposed.

scholarly journals Bacillus thermolactis sp. nov., isolated from dairy farms, and emended description of Bacillus thermoamylovorans

2011 ◽  
Vol 61 (8) ◽  
pp. 1954-1961 ◽  
Author(s):  
An Coorevits ◽  
Niall A. Logan ◽  
Anna E. Dinsdale ◽  
Gillian Halket ◽  
Patsy Scheldeman ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Type Strain ◽  
Gene Sequence ◽  
Sequence Similarity ◽  
Diaminopimelic Acid ◽  
16S Rrna Gene Sequence ◽  
Rrna Gene ◽  
Rrna Gene Sequence ◽  
Emended Description

A polyphasic taxonomic study was performed on 22 thermotolerant, aerobic, endospore-forming bacteria from dairy environments. Seventeen isolates were retrieved from raw milk, one from a filter cloth and four from grass, straw or milking equipment. These latter four isolates (R-6546, R-7499, R-7764 and R-7440) were identified as Bacillus thermoamylovorans based on DNA–DNA hybridizations (values above 70 % with Bacillus thermoamylovorans LMG 18084T) but showed discrepancies in characteristics with the original species description, so an emended description of this species is given. According to 16S rRNA gene sequence analysis and DNA–DNA hybridization experiments, the remaining 18 isolates (R-6488T, R-28193, R-6491, R-6492, R-7336, R-33367, R-6486, R-6770, R-31288, R-28160, R-26358, R-7632, R-26955, R-26950, R-33520, R-6484, R-26954 and R-7165) represented one single species, most closely related to Bacillus thermoamylovorans (93.9 % 16S rRNA gene sequence similarity), for which the name Bacillus thermolactis is proposed. Cells were Gram-stain-positive, facultatively anaerobic, endospore-forming rods that grew optimally at 40–50 °C. The cell wall peptidoglycan type of strain R-6488T, the proposed type strain, was A1γ based on meso-diaminopimelic acid. Major fatty acids of the strains were C16 : 0 (28.0 %), iso-C16 : 0 (12.1 %) and iso-C15 : 0 (12.0 %). MK-7 was the predominant menaquinone, and major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and some unidentified phospholipids. DNA G+C content was 35.0 mol%. Phenotypic properties allowed discrimination from other thermotolerant species of the genus Bacillus and supported the description of the novel species Bacillus thermolactis, with strain R-6488T ( = LMG 25569T  = DSM 23332T) as the proposed type strain.

scholarly journals Salinicoccus luteus sp. nov., isolated from a desert soil

2007 ◽  
Vol 57 (8) ◽  
pp. 1901-1905 ◽  
Author(s):  
Yu-Qin Zhang ◽  
Li-Yan Yu ◽  
Hong-Yu Liu ◽  
Yue-Qin Zhang ◽  
Li-Hua Xu ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Gene Sequence ◽  
Sequence Similarity ◽  
Desert Soil ◽  
16S Rrna Gene Sequence ◽  
Rrna Gene ◽  
The Novel ◽  
Rrna Gene Sequence ◽  
Moderately Halophilic Bacterium

A moderately halophilic bacterium, strain YIM 70202T, was isolated from a desert soil sample collected from Egypt and was subjected to a taxonomic investigation. In a phylogenetic dendrogram based on 16S rRNA gene sequence analysis, strain YIM 70202T was affiliated to the Salinicoccus clade, showing 94.5–96.8 % 16S rRNA gene sequence similarity to the recognized species of the genus Salinicoccus, in which Salinicoccus roseus CCM 3516T was the nearest neighbour. The DNA–DNA relatedness value of the novel isolate with S. roseus CCM 3516T was 12.7 %. The novel isolate grew at temperatures between 4 and 45 °C and at pH values ranging from 7.0 to 11.0, with an optimum of 30 °C and pH 8.0–9.0, respectively. Strain YIM 70202T grew optimally in the presence of 10 % NaCl (w/v) and growth was observed at NaCl concentrations in the range 1–25 % (w/v). Chemotaxonomic data revealed that strain YIM 70202T contained MK-6 as the predominant respiratory quinone, possessed l-Lys–Gly5 as the cell-wall peptidoglycan, had phosphatidylglycerol, diphosphatidylglycerol and an unknown glycolipid as the polar lipids and contained i-C15 : 0 and ai-C15 : 0 as the predominant fatty acids. The DNA G+C content was 49.7 mol%. The biochemical and chemotaxonomic properties demonstrate that strain YIM 70202T represents a novel species of the genus Salinicoccus. The name Salinicoccus luteus sp. nov. is proposed with strain YIM 70202T (=CGMCC 1.6511T=KCTC 3941T) as the type strain.

scholarly journals Paucibacter toxinivorans gen. nov., sp. nov., a bacterium that degrades cyclic cyanobacterial hepatotoxins microcystins and nodularin

2005 ◽  
Vol 55 (4) ◽  
pp. 1563-1568 ◽  
Author(s):  
Jarkko Rapala ◽  
Katri A. Berg ◽  
Christina Lyra ◽  
R. Maarit Niemi ◽  
Werner Manz ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Gene Sequence ◽  
Sequence Similarity ◽  
Carbon Sources ◽  
16S Rrna Gene Sequence ◽  
Rrna Gene ◽  
Rrna Gene Sequence

Thirteen bacterial isolates from lake sediment, capable of degrading cyanobacterial hepatotoxins microcystins and nodularin, were characterized by phenotypic, genetic and genomic approaches. Cells of these isolates were Gram-negative, motile by means of a single polar flagellum, oxidase-positive, weakly catalase-positive and rod-shaped. According to phenotypic characteristics (carbon utilization, fatty acid and enzyme activity profiles), the G+C content of the genomic DNA (66·1–68·0 mol%) and 16S rRNA gene sequence analysis (98·9–100 % similarity) the strains formed a single microdiverse genospecies that was most closely related to Roseateles depolymerans (95·7–96·3 % 16S rRNA gene sequence similarity). The isolates assimilated only a few carbon sources. Of the 96 carbon sources tested, Tween 40 was the only one used by all strains. The strains were able to mineralize phosphorus from organic compounds, and they had strong leucine arylamidase and chymotrypsin activities. The cellular fatty acids identified from all strains were C16 : 0 (9·8–19 %) and C17 : 1 ω7c (<1–5·8 %). The other predominant fatty acids comprised three groups: summed feature 3 (<1–2·2 %), which included C14 : 0 3-OH and C16 : 1 iso I, summed feature 4 (54–62 %), which included C16 : 1 ω7c and C15 : 0 iso OH, and summed feature 7 (8·5–28 %), which included ω7c, ω9c and ω12t forms of C18 : 1. A more detailed analysis of two strains indicated that C16 : 1 ω7c was the main fatty acid. The phylogenetic and phenotypic features separating our strains from recognized bacteria support the creation of a novel genus and species, for which the name Paucibacter toxinivorans gen. nov., sp. nov. is proposed. The type strain is 2C20T (=DSM 16998T=HAMBI 2767T=VYH 193597T).

scholarly journals Lactobacillus hammesii sp. nov., isolated from French sourdough

2005 ◽  
Vol 55 (2) ◽  
pp. 763-767 ◽  
Author(s):  
Rosica Valcheva ◽  
Maher Korakli ◽  
Bernard Onno ◽  
Hervé Prévost ◽  
Iskra Ivanova ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Gene Sequence ◽  
Fragment Length Polymorphism ◽  
Sequence Similarity ◽  
16S Rrna Gene Sequence ◽  
Rrna Gene ◽  
Rrna Gene Sequence ◽  
Gene Sequence Analysis ◽  
Different Strains

Twenty morphologically different strains were chosen from French wheat sourdough isolates. Cells were Gram-positive, non-spore-forming, non-motile rods. The isolates were identified using amplified-fragment length polymorphism, randomly amplified polymorphic DNA and 16S rRNA gene sequence analysis. All isolates were members of the genus Lactobacillus. They were identified as representing Lactobacillus plantarum, Lactobacillus paralimentarius, Lactobacillus sanfranciscensis, Lactobacillus spicheri and Lactobacillus sakei. However, two isolates (LP38T and LP39) could be clearly discriminated from recognized Lactobacillus species on the basis of genotyping methods. 16S rRNA gene sequence similarity and DNA–DNA relatedness data indicate that the two strains belong to a novel Lactobacillus species, for which the name Lactobacillus hammesii is proposed. The type strain is LP38T (=DSM 16381T=CIP 108387T=TMW 1.1236T).

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