scholarly journals Genome-Based Taxonomic Rearrangement of the Order Geobacterales Including the Description of Geomonas azotofigens sp. nov. and Geomonas diazotrophica sp. nov.

2021 ◽  
Vol 12 ◽  
Author(s):  
Zhenxing Xu ◽  
Yoko Masuda ◽  
Xueding Wang ◽  
Natsumi Ushijima ◽  
Yutaka Shiratori ◽  
...  

Geobacterales is a recently proposed order comprising members who originally belonged to the well-known family Geobacteraceae, which is a key group in terrestrial ecosystems involved in biogeochemical cycles and has been widely investigated in bioelectrochemistry and bioenergy fields. Previous studies have illustrated the taxonomic structure of most members in this group based on genomic phylogeny; however, several members are still in a pendent or chaotic taxonomic status owing to the lack of genome sequences. To address this issue, we performed this taxonomic reassignment using currently available genome sequences, along with the description of two novel paddy soil-isolated strains, designated Red51T and Red69T, which are phylogenetically located within this order. Phylogenomic analysis based on 120 ubiquitous single-copy proteins robustly separated the species Geobacter luticola from other known genera and placed the genus Oryzomonas (fam. Geobacteraceae) into the family ‘Pseudopelobacteraceae’; thus, a novel genus Geomobilimonas is proposed, and the family ‘Pseudopelobacteraceae’ was emended. Moreover, genomic comparisons with similarity indexes, including average amino acid identity (AAI), percentage of conserved protein (POCP), and average nucleotide identity (ANI), showed proper thresholds as genera boundaries in this order with values of 70%, 65%, and 74% for AAI, POCP, and ANI, respectively. Based on this, the three species Geobacter argillaceus, Geobacter pelophilus, and Geobacter chapellei should be three novel genera, for which the names Geomobilibacter, Geoanaerobacter, and Pelotalea are proposed, respectively. In addition, the two novel isolated strains phylogenetically belonged to the genus Geomonas, family Geobacteraceae, and shared genomic similarity values higher than those of genera boundaries, but lower than those of species boundaries with each other and their neighbors. Taken together with phenotypic and chemotaxonomic characteristics similar to other Geomonas species, these two strains, Red51T and Red69T, represent two novel species in the genus Geomonas, for which the names Geomonas azotofigens sp. nov. and Geomonas diazotrophica sp. nov. are proposed, respectively.

Author(s):  
Soon Dong Lee ◽  
In Seop Kim ◽  
Hanna Choe ◽  
Ji-Sun Kim

A Gram-negative, facultatively anaerobic bacterium, designated SAP-6T, was isolated from sap extracted from Acer pictum in Mt. Halla in Jeju, Republic of Korea and its precise taxonomic status was determined by a polyphasic approach. Cells were non-sporulating, motile, short rods and showed growth at 4–37 °C, pH 6.0–8.0 and 0–4% NaCl. Phylogenomic analysis based on 92 core gene sequences showed that strain SAP-6T belonged to the family Pectobacteriaceae and formed a distinct clade between members of the genera Sodalis and Biostraticola with gene support index of 89. The closest phylogenetic neighbours were Biostraticola tofi DSM 19580T (97.3% 16S rRNA gene sequence similarity) and Sodalis praecaptivus HS1T (96.8%), with the average amino acid identity values of 75.3% and 74.0%, respectively. The major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and an unidentified aminophospholipid. The major isoprenoid quinones were Q-7 and Q-8. The predominant fatty acids were C16:0, C17:0 cyclo and summed feature 3. The DNA G+C content was 57.0%. On the basis of data presented here, strain SAP-6T (=KCTC 52622T=DSM 104038T) represents a novel species of a new genus in the family Pectobacteriaceae , for which the name Acerihabitans arboris gen. nov., sp. nov. is proposed.


2020 ◽  
Vol 70 (8) ◽  
pp. 4470-4495 ◽  
Author(s):  
Lin Xu ◽  
Cong Sun ◽  
Chen Fang ◽  
Aharon Oren ◽  
Xue-Wei Xu

The family Erythrobacteraceae , belonging to the order Sphingomonadales , class Alphaproteobacteria , is globally distributed in various environments. Currently, this family consist of seven genera: Altererythrobacter , Croceibacterium , Croceicoccus , Erythrobacter , Erythromicrobium , Porphyrobacter and Qipengyuania . As more species are identified, the taxonomic status of the family Erythrobacteraceae should be revised at the genomic level because of its polyphyletic nature evident from 16S rRNA gene sequence analysis. Phylogenomic reconstruction based on 288 single-copy orthologous clusters led to the identification of three separate clades. Pairwise comparisons of average nucleotide identity, average amino acid identity (AAI), percentage of conserved protein and evolutionary distance indicated that AAI and evolutionary distance had the highest correlation. Thresholds for genera boundaries were proposed as 70 % and 0.4 for AAI and evolutionary distance, respectively. Based on the phylo-genomic and genomic similarity analysis, the three clades were classified into 16 genera, including 11 novel ones, for which the names Alteraurantiacibacter, Altericroceibacterium, Alteriqipengyuania, Alteripontixanthobacter, Aurantiacibacter, Paraurantiacibacter, Parerythrobacter, Parapontixanthobacter, Pelagerythrobacter, Tsuneonella and Pontixanthobacter are proposed. We reclassified all species of Erythromicrobium and Porphyrobacter as species of Erythrobacter . This study is the first genomic-based study of the family Erythrobacteraceae , and will contribute to further insights into the evolution of this family.


Author(s):  
Peter Schumann ◽  
Franziska Kalensee ◽  
Jialan Cao ◽  
Alexis Criscuolo ◽  
Dominique Clermont ◽  
...  

In the course of screening the surface soils of ancient copper mines and smelters (East Harz, Germany) an aerobic, non-motile and halotolerant actinobacterium forming small rods or cocci was isolated. The strain designated F300T developed creamy to yellow colonies on tryptone soy agar and grew optimally at 28 °C, pH 7–8 and with 0.5–2 % (m/v) NaCl. Its peptidoglycan was of type A4α l-Lys–l-Glu (A11.54). The menaquinone profile was dominated by MK-8(II, III-H4) and contained minor amounts of MK-8(H2), MK-8(H6) and MK-9(H4). The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, mono and diacylated phosphatidylinositol dimannosides, and components that were not fully characterized, including two phospholipids, two glycolipids and an uncharacterized lipid. Major whole-cell sugars were rhamnose and ribose. The fatty acid profile contained mainly iso and anteiso branched fatty acids (anteiso-C15 : 0, iso-C14 : 0) and aldehydes/dimethylacetals (i.e. not fatty acids). Sequence analysis of its genomic DNA and subsequent analysis of the data placed the isolate in the group currently defined by members of the genera Ruania and Haloactinobacterium (family Ruaniaceae , order Micrococcales ) as a sister taxon to the previously described species Haloactinobacterium glacieicola , sharing an average nucleotide identity and average amino acid identity values of 85.3 and 85.7 %, respectively. Genotypic and chemotaxonomic analyses support the view that strain F300T (=DSM 108350T=CIP 111667T) is the type strain of a new genus and new species for which the name Occultella aeris gen. nov., sp. nov. is proposed. Based on revised chemotaxonomic and additional genome based data, it is necessary to discuss and evaluate the results in the light of the classification and nomenclature of members of the family Ruaniaceae , i.e. the genera Haloactinobacterium and Ruania . Consequently, the reclassification of Haloactinobacterium glacieicola as Occultella glacieicola comb. nov. and Haloactinobacterium album as Ruania alba comb. nov., with an emended description of the genus Ruania are proposed.


2020 ◽  
Vol 70 (4) ◽  
pp. 2873-2878 ◽  
Author(s):  
María José León ◽  
Cristina Galisteo ◽  
Antonio Ventosa ◽  
Cristina Sánchez-Porro

A comparative taxonomic study of Spiribacter and Halopeptonella species was carried out using a phylogenomic approach based on comparison of the core genome, orthologous average nucleotide identity (OrthoANIu), Genome-to-Genome Distance Calculator (GGDC) and average amino acid identity (AAI). Phylogenomic analysis based on 976 core translated gene sequences obtained from their genomes showed that Spiribacter aquaticus SP30T, S. curvatus UAH-SP71T, S. roseus SSL50T, S. salinus M19-40T and Halopeptonella vilamensis DSM 21056T formed a robust cluster, clearly separated from the remaining species of closely related taxa. AAI between H. vilamensis DSM 21056T and the species of the genus Spiribacter was ≥73.1 %, confirming that all these species belong to the same single genus. On the other hand, S. roseus SSL50T and S. aquaticus SP30T showed percentages of OrthoANIu and digital DNA–DNA hybridization of 98.4 % and 85.3 %, respectively, while these values among those strains and the type strains of the other species of Spiribacter and H. vilamensis DSM 21056T were ≤80.8 and 67.8 %, respectively. Overall, these data show that S. roseus SSL50T and S. aquaticus SP30T constitute a single species and thus that S. aquaticus SP30T should be considered as a later, heterotypic synonym of S. roseus SSL50T based on the rules for priority of names. We propose an emended description of S. roseus , including the features of S. aquaticus . We also propose the reclassification of H. vilamensis as Spiribacter vilamensis comb. nov.


Author(s):  
Kyung June Yim ◽  
Dong-Hyun Jung ◽  
Seok Won Jang ◽  
Sanghwa Park

A cream-coloured, Gram-stain-negative, rod-shaped bacterium, designated strain KSC-6T, was isolated from soil sampled at the Gapcheon River watershed in Daejeon, Republic of Korea. The organism does not require NaCl for growth and grows at pH 6.0–8.0 (optimum, pH 7.0) and 10–37 °C (optimum, 25 °C). Phylogenetic trees based on the 16S rRNA gene sequences reveal that strain KSC-6T belongs to the family Chitinophagaceae within the order Chitinophagales and is most closely related to Panacibacter ginsenosidivorans Gsoil 1550T (95.9% similarity). The genomic DNA G+C content was 38.9 mol%. The major cellular fatty acids (>8 %) of strain KCS-6T were iso-C15:0, iso-C15 : 1 G and iso-C17 : 0 3-OH. The predominant respiratory quinone was menaquinone 7 and the predominant polar lipids were phosphatidylethanolamine, five unidentified aminolipids and two unidentified lipids. Based on genome analyses, low digital DNA–DNA hybridization, average nucleotide identity and average amino acid identity values with closely related genera, and differential chemotaxonomic and physiological properties, we suggest that strain KCS-6T represents a novel species in a new genus in the family Chitinophagaceae , for which the name Limnovirga soli gen. nov., sp. nov. (type strain KCS-6T=KCCM 43337T=NBRC 114336T) is proposed.


2020 ◽  
Vol 8 (5) ◽  
pp. 634 ◽  
Author(s):  
Zhenxing Xu ◽  
Yoko Masuda ◽  
Chie Hayakawa ◽  
Natsumi Ushijima ◽  
Keisuke Kawano ◽  
...  

Bacteria of the family Geobacteraceae are particularly common and deeply involved in many biogeochemical processes in terrestrial and freshwater environments. As part of a study to understand biogeochemical cycling in freshwater sediments, three iron-reducing isolates, designated as Red96T, Red100T, and Red88T, were isolated from the soils of two paddy fields and pond sediment located in Japan. The cells were Gram-negative, strictly anaerobic, rod-shaped, motile, and red-pigmented on agar plates. Growth of these three strains was coupled to the reduction of Fe(III)-NTA, Fe(III) citrate, and ferrihydrite with malate, methanol, pyruvate, and various organic acids and sugars serving as alternate electron donors. Phylogenetic analysis based on the housekeeping genes (16S rRNA gene, gyrB, rpoB, nifD, fusA, and recA) and 92 concatenated core genes indicated that all the isolates constituted a coherent cluster within the family Geobacteraceae. Genomic analyses, including average nucleotide identity and DNA–DNA hybridization, clearly differentiated the strains Red96T, Red100T, and Red88T from other species in the family Geobacteraceae, with values below the thresholds for species delineation. Along with the genomic comparison, the chemotaxonomic features further helped distinguish the three isolates from each other. In addition, the lower values of average amino acid identity and percentage of conserved protein, as well as biochemical differences with their relatives, indicated that the three strains represented a novel genus in the family Geobacteraceae. Hence, we concluded that strains Red96T, Red100T, and Red88T represented three novel species of a novel genus in the family Geobacteraceae, for which the names Oryzomonas japonicum gen. nov., sp. nov., Oryzomonas sagensis sp. nov., and Oryzomonas ruber sp. nov. are proposed, with type strains Red96T (= NBRC 114286T = MCCC 1K04376T), Red100T (= NBRC 114287T = MCCC 1K04377T), and Red88T (= MCCC 1K03694T = JCM 33033T), respectively.


2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Hans Jonsson ◽  
Luisa W. Hugerth ◽  
John Sundh ◽  
Eva Lundin ◽  
Anders F. Andersson

AbstractSegmented filamentous bacteria (SFB) are unique immune modulatory bacteria colonizing the small intestine of a variety of animals in a host-specific manner. SFB exhibit filamentous growth and attach to the host’s intestinal epithelium, offering a physical route of interaction. SFB affect functions of the host immune system, among them IgA production and T-cell maturation. Until now, no human-specific SFB genome has been reported. Here, we report the metagenomic reconstruction of an SFB genome from a human ileostomy sample. Phylogenomic analysis clusters the genome with SFB genomes from mouse, rat and turkey, but the genome is genetically distinct, displaying 65–71% average amino acid identity to the others. By screening human faecal metagenomic datasets, we identified individuals carrying sequences identical to the new SFB genome. We thus conclude that a unique SFB variant exists in humans and foresee a renewed interest in the elucidation of SFB functionality in this environment.


1992 ◽  
Vol 6 ◽  
pp. 234-234
Author(s):  
E. M. Pike

Assessment of changes in terrestrial ecosystems since Cretaceous time, until recently, has had to rely on paleobotany (including paleopalynology) and vertebrate paleontology to provide data for analysis. Insects contribute a major portion of the terrestrial diversity in any ecosystem, but their fossil record and state of preservation had discouraged paleoecological study beyond the Pleistocene. With the discovery of prolific Upper Cretaceous amber deposits in Russia and Canada, and the investigation of Tertiary amber deposits from the Baltic, the Dominican Republic, Mexico and the USA, the prospect of clarifying changes in insect diversity and ecology over time becomes real. Methods are reported which allow the description of species richness and relative abundance of arthropod taxa from an Upper Cretaceous (Campanian: 75 MYA) amber deposit in Alberta, Canada. Diversity and abundance are described at the Order level for hexapods, and for the Acarina and Araneae. Taxa present, in order of abundance, are Homoptera (66 specimens/kg of amber), Diptera (28/kg), Acarina (21/kg), Hymenoptera (13/kg), Araneae (12/kg), Psocoptera (4/kg), Coleoptera (2/kg), Blattodea (1/kg), Thysanoptera (1/kg), Trichoptera (0.6/kg). Other orders present are Lepidoptera, Collembola, Dermaptera, Mantodea, and Ephemeroptera. In total, of 35 identified families, 8 are extinct. There are about 20 genera identified, of which only 1 is extant. All identified species are extinct. Estimated species richness is about 100 species of arthropods. In comparison, virtually all Families reported from Baltic amber (Oligocene) are still extant, as are the majority of genera. Morphology and feeding structures are well within the variation seen in modern insects. This suggests that throughout the Tertiary, Entomologists would feel quite at home with the insect fauna, and during the Upper Cretaceous, they would have little difficulty identifying insects at least to the family level. It is hypothesized that the taxonomic structure of modern insect communities was well established before the end of the Cretaceous, and that the structure and interrelationships of insect guilds were also very similar to those of today.


F1000Research ◽  
2013 ◽  
Vol 2 ◽  
pp. 67 ◽  
Author(s):  
Cristiane C Thompson ◽  
Vanessa E Emmel ◽  
Erica L Fonseca ◽  
Michel A Marin ◽  
Ana Carolina P Vicente

The identification of the clinically relevant viridans streptococci group, at species level, is still problematic. The aim of this study was to extract taxonomic information from the complete genome sequences of 67 streptococci, comprising 19 species, by means of genomic analyses, multilocus sequence analysis (MLSA), average amino acid identity (AAI), genomic signatures, genome-to-genome distances (GGD) and codon usage bias. We then attempted to determine the usefulness of these genomic tools for species identification in streptococci. Our results showed that MLSA, AAI and GGD analyses are robust markers to identify streptococci at the species level, for instance,S. pneumoniae,S. mitis, andS. oralis. AStreptococcusspecies can be defined as a group of strains that share ≥ 95% DNA similarity in MLSA and AAI, and > 70% DNA identity in GGD. This approach allows an advanced understanding of bacterial diversity.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e6032 ◽  
Author(s):  
Zhenyu Zhao ◽  
Xin Wang ◽  
Yi Yu ◽  
Subo Yuan ◽  
Dan Jiang ◽  
...  

Dioscorea L., the largest genus of the family Dioscoreaceae with over 600 species, is not only an important food but also a medicinal plant. The identification and classification of Dioscorea L. is a rather difficult task. In this study, we sequenced five Dioscorea chloroplast genomes, and analyzed with four other chloroplast genomes of Dioscorea species from GenBank. The Dioscorea chloroplast genomes displayed the typical quadripartite structure of angiosperms, which consisted of a pair of inverted repeats separated by a large single-copy region, and a small single-copy region. The location and distribution of repeat sequences and microsatellites were determined, and the rapidly evolving chloroplast genome regions (trnK-trnQ, trnS-trnG, trnC-petN, trnE-trnT, petG-trnW-trnP, ndhF, trnL-rpl32, and ycf1) were detected. Phylogenetic relationships of Dioscorea inferred from chloroplast genomes obtained high support even in shortest internodes. Thus, chloroplast genome sequences provide potential molecular markers and genomic resources for phylogeny and species identification.


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