scholarly journals PCR-Induced Sequence Artifacts and Bias: Insights from Comparison of Two 16S rRNA Clone Libraries Constructed from the Same Sample

2005 ◽  
Vol 71 (12) ◽  
pp. 8966-8969 ◽  
Author(s):  
Silvia G. Acinas ◽  
Ramahi Sarma-Rupavtarm ◽  
Vanja Klepac-Ceraj ◽  
Martin F. Polz

ABSTRACT The contribution of PCR artifacts to 16S rRNA gene sequence diversity from a complex bacterioplankton sample was estimated. Taq DNA polymerase errors were found to be the dominant sequence artifact but could be constrained by clustering the sequences into 99% sequence similarity groups. Other artifacts (chimeras and heteroduplex molecules) were significantly reduced by employing modified amplification protocols. Surprisingly, no skew in sequence types was detected in the two libraries constructed from PCR products amplified for different numbers of cycles. Recommendations for modification of amplification protocols and for reporting diversity estimates at 99% sequence similarity as a standard are given.

Author(s):  
Shadi Khodamoradi ◽  
Richard L. Hahnke ◽  
Yvonne Mast ◽  
Peter Schumann ◽  
Peter Kämpfer ◽  
...  

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.


2014 ◽  
Vol 64 (Pt_11) ◽  
pp. 3877-3884 ◽  
Author(s):  
Celine De Maesschalck ◽  
Filip Van Immerseel ◽  
Venessa Eeckhaut ◽  
Siegrid De Baere ◽  
Margo Cnockaert ◽  
...  

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.


2006 ◽  
Vol 56 (11) ◽  
pp. 2579-2582 ◽  
Author(s):  
Jee-Min Lim ◽  
Che Ok Jeon ◽  
Dong-Jin Park ◽  
Li-Hua Xu ◽  
Cheng-Lin Jiang ◽  
...  

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.


2005 ◽  
Vol 55 (2) ◽  
pp. 885-889 ◽  
Author(s):  
In-Gi Kim ◽  
Mi-Hwa Lee ◽  
Seo-Youn Jung ◽  
Jae Jun Song ◽  
Tae-Kwang Oh ◽  
...  

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.


2004 ◽  
Vol 54 (5) ◽  
pp. 1799-1803 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
Soo-Hwan Yeo ◽  
In-Gi Kim ◽  
Tae-Kwang Oh

Two Gram-negative, motile, non-spore-forming and slightly halophilic rods (strains SW-145T and SW-156T) were isolated from sea water of the Yellow Sea in Korea. Strains SW-145T and SW-156T grew optimally at 37 and 30–37 °C, respectively, and in the presence of 2–6 % (w/v) NaCl. Strains SW-145T and SW-156T were chemotaxonomically characterized as having ubiquinone-9 as the predominant respiratory lipoquinone and C16 : 0, C18 : 1 ω9c, C16 : 1 ω9c and C12 : 0 3-OH as the major fatty acids. The DNA G+C contents of strains SW-145T and SW-156T were 58 and 57 mol%, respectively. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains SW-145T and SW-156T fell within the evolutionary radiation enclosed by the genus Marinobacter. The 16S rRNA gene sequences of strains SW-145T and SW-156T were 94·8 % similar. Strains SW-145T and SW-156T exhibited 16S rRNA gene sequence similarity levels of 94·3–98·1 and 95·4–97·7 %, respectively, with respect to the type strains of all Marinobacter species. Levels of DNA–DNA relatedness, together with 16S rRNA gene sequence similarity values, indicated that strains SW-145T and SW-156T are members of two species that are distinct from seven Marinobacter species with validly published names. On the basis of phenotypic properties and phylogenetic and genotypic distinctiveness, strains SW-145T (=KCTC 12185T=DSM 16070T) and SW-156T (=KCTC 12184T=DSM 16072T) should be placed in the genus Marinobacter as the type strains of two distinct novel species, for which the names Marinobacter flavimaris sp. nov. and Marinobacter daepoensis sp. nov. are proposed.


2011 ◽  
Vol 61 (8) ◽  
pp. 1954-1961 ◽  
Author(s):  
An Coorevits ◽  
Niall A. Logan ◽  
Anna E. Dinsdale ◽  
Gillian Halket ◽  
Patsy Scheldeman ◽  
...  

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.


2007 ◽  
Vol 57 (8) ◽  
pp. 1901-1905 ◽  
Author(s):  
Yu-Qin Zhang ◽  
Li-Yan Yu ◽  
Hong-Yu Liu ◽  
Yue-Qin Zhang ◽  
Li-Hua Xu ◽  
...  

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.


Author(s):  
Yong-Taek Jung ◽  
Soo-Young Lee ◽  
Won-Chan Choi ◽  
Tae-Kwang Oh ◽  
Jung-Hoon Yoon

A Gram-negative, non-sporulating, non-flagellated rod, designated BR-9T, was isolated from soil collected on the Korean peninsula. Strain BR-9T grew optimally at pH 6.0–7.0, at 30 °C and in the absence of NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain BR-9T belonged to the genus Pedobacter and clustered with Pedobacter insulae DS-139T and Pedobacter koreensis WPCB189T. Strain BR-9T exhibited 98.2 and 97.5 % 16S rRNA gene sequence similarity with P. insulae DS-139T and P. koreensis WPCB189T, respectively, and <96.7 % sequence similarity with the type strains of other species in the genus Pedobacter. Strain BR-9T contained MK-7 as the predominant menaquinone and iso-C15 : 0 and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH) as the major fatty acids. The DNA G+C content of strain BR-9T was 38.5 mol%. DNA–DNA relatedness between strain BR-9T and P. insulae DS-139T and P. koreensis KCTC 12536T was 3.4–4.2 %, which indicated that the isolate was genetically distinct from these type strains. Strain BR-9T was also distinguishable by differences in phenotypic properties. On the basis of the data presented, strain BR-9T is considered to represent a novel species of the genus Pedobacter, for which the name Pedobacter boryungensis sp. nov. is proposed. The type strain is BR-9T ( = KCTC 23344T  = CCUG 60024T).


2007 ◽  
Vol 57 (5) ◽  
pp. 947-950 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
So-Jung Kang ◽  
Jung-Sook Lee ◽  
Tae-Kwang Oh

A Gram-negative, rod-shaped, Flavobacterium-like bacterial strain, DS-20T, was isolated from soil from the island of Dokdo, Korea, and subjected to a polyphasic taxonomic study. Strain DS-20T grew optimally at pH 6.5–7.0 and 25 °C. It contained MK-6 as the predominant menaquinone and iso-C15 : 0, iso-C17 : 0 3-OH and iso-C17 : 1 ω9c as the major fatty acids. The DNA G+C content was 38.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain DS-20T belonged to the genus Flavobacterium. Levels of 16S rRNA gene sequence similarity between strain DS-20T and the type strains of recognized Flavobacterium species were below 94.9 %. Strain DS-20T differed from phylogenetically related Flavobacterium species in several phenotypic characteristics. On the basis of its phenotypic and phylogenetic distinctiveness, strain DS-20T was classified in the genus Flavobacterium as representing a novel species, for which the name Flavobacterium terrigena sp. nov. is proposed. The type strain is DS-20T (=KCTC 12761T=DSM 17934T).


2005 ◽  
Vol 55 (4) ◽  
pp. 1563-1568 ◽  
Author(s):  
Jarkko Rapala ◽  
Katri A. Berg ◽  
Christina Lyra ◽  
R. Maarit Niemi ◽  
Werner Manz ◽  
...  

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).


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