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1.
The genera Agrobacterium, Allorhizobium, and Rhizobium belong to the family Rhizobiaceae. However, the placement of a phytopathogenic group of bacteria, the genus Agrobacterium, among the nitrogen-fixing bacteria and the unclear position of Rhizobium galegae have caused controversy in previous taxonomic studies. To resolve uncertainties in the taxonomy and nomenclature within this family, the phylogenetic relationships of generic members of Rhizobiaceae were studied, but with particular emphasis on the taxa included in Agrobacterium and the “R. galegae complex” (R. galegae and related taxa), using multilocus sequence analysis (MLSA) of six protein-coding housekeeping genes among 114 rhizobial and agrobacterial taxa. The results showed that R. galegae, R. vignae, R. huautlense, and R. alkalisoli formed a separate clade that clearly represented a new genus, for which the name Neorhizobium is proposed. Agrobacterium was shown to represent a separate cluster of mainly pathogenic taxa of the family Rhizobiaceae. A. vitis grouped with Allorhizobium, distinct from Agrobacterium, and should be reclassified as Allorhizobium vitis, whereas Rhizobium rhizogenes was considered to be the proper name for former Agrobacterium rhizogenes. This phylogenetic study further indicated that the taxonomic status of several taxa could be resolved by the creation of more novel genera.  相似文献   

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The discovery in rocks of Middle Devonian age of a new Asteropyginae, Kayserops? cantarmoricus n. sp., common to both Central Armorican Syncline (Rade de Brest, France) and the south flank of the Cantabrian Mountains (Spain), suggests a geographical connection, perhaps temporary, between these two regions. The particular morphological characteristics of this species shed new light on present knowledge of the sub-family Asteropyginae.  相似文献   

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Flavobacterium arborescens (Frankland and Frankland) Bergey et al. IFO 3750 (ATCC 4358) is a Gram-positive, coryneform bacterium and the only available reference strain of the species. The cell wall peptidoglycan of the organism possesses alanine, glycine, lysine, glutamic acid plus 3-hydroxyglutamic acid, and homoserine at a ratio of 1:3:1:1:1, and a possible peptidoglycan structure is the B1 type described by Schleifer and Kandler. Cell wall sugars are galactose, mannose, and 6-deoxy-l-talose, but not rhamnose. Major menaquinones are unsaturated MK-11 and MK-12. These findings and other taxonomic properties suggest that F. arborescens should be reclassified in the genusMicrobacterium (Orla-Jensen) Collins et al., asMicrobacterium arborescens comb. nov., nom. rev.  相似文献   

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Strains T5K1 and AV446 isolated from apple cider vinegars during a submerged vinegar production in two separate vinegar facilities showed 94% 16S rRNA gene similarity to its closest neighbors Komagataeibacter maltaceti LMG 1529T and Gluconacetobacter entanii LTH 4560T. Further phylogenetic and phenotypic characterizations indicated that the isolates belonged to a novel species of the Komagataeibacter genus. Comparison based on 16S–23S rRNA gene ITS sequences and concatenated partial sequences of the housekeeping genes dnaK, groEL and rpoB, grouped both strains to a single phylogenetic cluster well separated from the other species of the Komagataeibacter genus. Average nucleotide identity of T5K1 and AV446 draft genome sequences compared to other Komagataeibacter type strains was below 94% and at the same time, in-silico DNA–DNA hybridization was below 70%. Both strains on the other hand showed approximately 98% (average nucleotide identity) and 87% (in silico DNA–DNA hybridization) similarity to each other. Strains T5K1 and AV446 can be differentiated from other Komagataeibacter type strains based on their ability to produce 2-keto-d-gluconic acid and at the same time inability to produce 5-keto-d-gluconic acid. Furthermore, strains of the new species do not grow on Asai medium supplemented with d-glucose or d-mannitol. The growth is also absent (T5K1) or weak (AV446) on Hoyer–Frateur medium supplemented with afore mentioned sugars. Both strains produce cellulose. In addition, draft genome analysis revealed that strains T5K1 and AV446 possess genes involved in the synthesis of acetan-like extracellular heteropolysaccharide. We propose the name Komagataeibacter pomaceti sp. nov. for the new species with LMG 30150T [= CCM 8723T = ZIM B1029T] as the type strain. Data collected in this study and in a previous study also revealed that Komagataeibacter kombuchae is a later heterotypic synonym of Komagataeibacter hansenii.  相似文献   

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For many years, the binomial Hygrophorus hypothejus was widely applied to collections from various geographical regions in different continents, assuming a circum-boreal and circum-mediterranean distribution for this species. This hypothesis, however, had never been put to the test. To assess the diversity and species-limits within this complex of yellow-coloured waxcaps, a phylogenetic, morphological and taxonomical investigation into Hygrophorus sect. Aurei and similar species in sect. Olivaceoumbrini was carried out, including material of pan-European origin, as well as the east and west coasts of North America. Following sequencing of the ITS rDNA locus, nine lineages are confirmed in sect. Aurei, most of them highly continentalised. Of these, two are new to science, introduced here as Hygrophorus boyeri sp. nov., from Pinus banksiana and P. rigida forests in eastern North America and from P. muricata and P. contorta forests in western North America, and Hygrophorus meridionalis sp. nov., from Pinus brutia and Pinus halepensis forests in the island of Cyprus and mainland Greece. H. hypothejus is lectotypified and epitypified, and here resolved as a strictly European species, with the old forgotten taxon Hygrophorus siccipes revived as its North American vicariant. The placement of Hygrophorus fuligineus in sect. Aurei is phylogenetically confirmed and detailed comparisons between morphologically similar and phylogenetically affiliated taxa in sect. Aurei and sect. Olivaceoumbrini are provided. The chronic confusion associated with Hygrophorus fuscoalbus, a highly controversial taxon described from Germany nearly two centuries ago and variously interpreted since, is discussed, concluding that this name is too ambiguous to be applied to any currently recognized species.  相似文献   

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The monotonous cordaitalean leaves are usually difficult to determine as leaf shape and venation can be similar in many species. Therefore cuticular analysis is an important method for distinguishing cordaitalean leaves. Pennsylvanian Cordaites schatzlarensis nov. sp. comes from the ?aclé? locality in the Intrasudetic Basin, Czech Republic. It has been found in mudstone accompanying the upper coal seams No. 9 and 10 of the Jan Šverma Coals, Lampertice Member, ?aclé? Formation and are late Duckmantian in age. The leaves of Cordaites schatzlarensis are lanceolate, amphistomatic. Stomata of the adaxial epidermis are scarce, isolated, or in very short stomatal rows. In contrast, the density of stomata on the abaxial cuticle is high and stomata are arranged into single or double stomatal rows. The cuticles of C. schatzlarensis are comparable with the Chinese Upper Permian C. baodeensis Ge. Leaves can be narrow, comparable to French Bolsovian Dorycordaites zeilleri Ledran, or relatively wide. Accompanying big seeds more than 5 cm in diameter are attributed to Samaropsis newberryi (Andrews) Seward. The pith casts Artisia Sternberg were found in sandy channel fill deposits.  相似文献   

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In the course of studying the influence of N-fertilization on N2 and N2O flux rates in relation to soil bacterial community composition of a long-term fertilization experiment in fen peat grassland, a strain group was isolated that was related to a strain isolated from a spacecraft assembly clean room during diversity studies of microorganisms, which withstood cleaning and bioburden reduction strategies. Both the fen soil isolates and the clean room strain revealed versatile physiological capacities in N-transformation processes by performing heterotrophic nitrification, respiratory ammonification and denitrification activity.  相似文献   

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Rossmania ukurunduensis gen. and sp. nov. collected in the reverve Bolshekhekhtsirsky (Khabarovsk Territory, Russian Far East) is described and illustrated.Rossmania aculeata comb. Nov. is indicated as the second species of the genus.  相似文献   

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Isolates AH11T and AH13T were isolated from flowers of lantana and candle bush respectively collected in Thailand. In phylogenetic trees based on 16S rRNA gene sequences, the two isolates formed an independent cluster, which was then connected to the type strain of Saccharibacter floricola. The calculated pair-wise 16S rRNA gene sequence similarities of isolate AH11T were 95.7–92.3% to the type strains of the type species of the 12 genera of acetic acid bacteria. The DNA base composition was from 51.2 to 56.8 mol % G+C, with a range of 5.6 mol %. When isolate AH11T was labeled, DNA-DNA similarities were 100, 12, 4, 5, and 4% respectively to isolates AH11T and AH13T and the type strains of Saccharibacter floricola, Gluconobacter oxydans, and Acetobacter aceti. The two isolates were non-motile and did not oxidize either acetate or lactate. No growth was found in the presence of 0.35% acetic acid w/v. The two isolates were not osmophilic but osmotolerant, produced 2,5-diketo-D-gluconate from D-glucose, and did not oxidize lactate, thus differing from strains of Saccharibacter floricola, which showed weak lactate oxidation. The two isolates contained unsaturated C18:1ω7c fatty acid as the major fatty acid, and were unique in the presence of a considerable amount of straight-chain C18:12OH fatty acid. Q-10 was present as the major isoprenoid quinone. Neokomagataea gen. nov. was proposed with the two species, Neokomagataea thailandica sp. nov. for isolate AH11T (=BCC 25710 T =NBRC 106555T), which has 56.8 mol % G+C, and Neokomagataea tanensis sp. nov. for isolate AH13T (=BCC 25711T=NBRC 106556T), which has 51.2 mol % G+C.  相似文献   

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Jean Roman 《Geobios》1977,10(3):337-349
Echinolampas is a subtropical genus living in rather shallow water; one may regards it as a climatic marker. The theory of continental drift affords a rather good explanation for its distribution in space during Cenozoic era. It appears in Old Wolrd during Paleocene and it occurs in Central America during Middle Eocene; that implies it had to cross the already broad Atlantic Ocean; but at that time this ocean is not as broad at it is now. Migration along the shelf area which rimmed North Atlantic might have been impossible, owing to disruption of land connection between Europe and North America. Probably the migration occured in low latitudes and pelagic larvae were transported by one of the two equatorial currents. Diversity of the genus has much decreased during Late Eocene. The cause may be chiefly due to climatic deterioration, resulting from marine communication between North Atlantic and Arctic Ocean. Echinolampas occurs for the first time in Australia during Oligocene. One may suggest the possibility of a link between this late evidence and the quite remote position till then of Australian continent. During Miocene, the relative decrease in Echinolampas diversity in the Mediterranean Basin occurs as a result of the welding between Asia and Africa.  相似文献   

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Isolates AH11(T) and AH13(T) were isolated from flowers of lantana and candle bush respectively collected in Thailand. In phylogenetic trees based on 16S rRNA gene sequences, the two isolates formed an independent cluster, which was then connected to the type strain of Saccharibacter floricola. The calculated pair-wise 16S rRNA gene sequence similarities of isolate AH11(T) were 95.7-92.3% to the type strains of the type species of the 12 genera of acetic acid bacteria. The DNA base composition was from 51.2 to 56.8 mol % G+C, with a range of 5.6 mol %. When isolate AH11(T) was labeled, DNA-DNA similarities were 100, 12, 4, 5, and 4% respectively to isolates AH11(T) and AH13(T) and the type strains of Saccharibacter floricola, Gluconobacter oxydans, and Acetobacter aceti. The two isolates were non-motile and did not oxidize either acetate or lactate. No growth was found in the presence of 0.35% acetic acid w/v. The two isolates were not osmophilic but osmotolerant, produced 2,5-diketo-D-gluconate from D-glucose, and did not oxidize lactate, thus differing from strains of Saccharibacter floricola, which showed weak lactate oxidation. The two isolates contained unsaturated C(18:1)ω7c fatty acid as the major fatty acid, and were unique in the presence of a considerable amount of straight-chain C(18:1)2OH fatty acid. Q-10 was present as the major isoprenoid quinone. Neokomagataea gen. nov. was proposed with the two species, Neokomagataea thailandica sp. nov. for isolate AH11(T) (=BCC 25710(T)=NBRC 106555(T)), which has 56.8 mol % G+C, and Neokomagataea tanensis sp. nov. for isolate AH13(T) (=BCC 25711(T)=NBRC 106556(T)), which has 51.2 mol % G+C.  相似文献   

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