Genus Kribbella Research Articles

Seven New Actinobacterial Species of the Genus Kribbella with Unique Cell Wall Glycopolymers, and Emended Description of the Genus Kribbella

Seven New Actinobacterial Species of the Genus Kribbella with Unique Cell Wall Glycopolymers, and Emended Description of the Genus Kribbella

Seven New Actinobacterial Species of the Genus <i>Kribbella</i> with Unique Cell Wall Glycopolymers, and Emended Description of the Genus <i>Kribbella</i>

Abstract—Seven actinomycete strains assigned to seven new species of the genus Kribbella were isolated from soils of different regions in Russia. The strains exhibited 98.2–99.3% similarity of the 16S rRNA gene sequences to each other and 96.2–99.7% similarity to the type strains of the known Kribbella species. The evolutionary distances calculated on the basis of concatenated gene sequences (gyrB–rpoB–recA–relA–atpD, 4108 nt) for the studied organisms and type strains of the known species were within the range reported for Kribbella species (0.014–0.101). The dDDH and ANIb values for the strains studied and the type strains of validly described species with available genomes were below the threshold (49.8 and 92.6%, respectively) for prokaryote specie delineation. Members of the putative new species possessed individual phenotypic profiles; some species were found (for the first time in Kribbella) to produce sporangium-like structures, up to 4 μm in diameter. The cell walls of the studied strains contained the teichuronic and/or teichulosonic acids specific for the species or species groups and not described previously for other prokaryotes. The unique branched α-mannan occurred in all studied strains of the genus. Based on the data obtained and the previously published data, the following new species are proposed: Kribbella orskensis sp. nov. (type strain ВКМ Ас-2538T), Kribbella rubisoli sp. nov. (type strain VKM Aс-2540T), Kribbella antiqua sp. nov. (type strain VKM Ас-2541T), Kribbella kalugense sp. nov. (type strain VKM Ас-2570T), Kribbella steрpae sp. nov. (type strain ВКМ Ас-2572T), Kribbella pratae sp. nov. (type strain ВКМ Ас-2574T), and Kribbella voronezhensis sp. nov. (type strain VKM Ас-2575T) with emended description of the genus Kribbella.

Oxalate utilisation is widespread in the actinobacterial genus Kribbella

The type strains of all 33 species in the genus Kribbella were tested for growth on oxalate (−OOC-COO−) as sole carbon source. Media were initially formulated to contain sodium oxalate, but even a concentration as low as 7.5 mM oxalate prevented growth. A modified medium based on calcium oxalate was very successful in characterising oxalate utilisation by Kribbella strains (metabolism of oxalate by oxalotrophic bacteria results in visible zones of clearing around the growth streaks on the opaque plates). To assess the variability of oxalate utilisation in Kribbella species, we also tested eight non-type strains for their ability to use oxalate. Thirty of 33 type strains (90.9%) and six of eight non-type strains (75%) were able to use oxalate as a sole carbon source. Based on these results, we propose that oxalate would be an excellent carbon source for the selective isolation of Kribbella strains. Based on the oxalate-utilisation phenotype and analyses of the 19 publicly available Kribbella type-strain genome sequences, we propose a pathway for oxalate metabolism in Kribbella. This pathway is significantly different from those previously proposed for oxalate metabolism in other bacteria, involving the indirect catabolism of oxalate to formate. Formate production is proposed to be involved in energy generation and to be crucial for oxalate import via an oxalate:formate antiporter. To our knowledge, this is the first report of an oxalate:formate antiporter in an aerobic, Gram-positive bacterium.

Novel South African Rare Actinomycete Kribbella speibonae Strain SK5: A Prolific Producer of Hydroxamate Siderophores Including New Dehydroxylated Congeners.

In this paper, we report on the chemistry of the rare South African Actinomycete Kribbella speibonae strain SK5, a prolific producer of hydroxamate siderophores and their congeners. Two new analogues, dehydroxylated desferrioxamines, speibonoxamine 1 and desoxy-desferrioxamine D1 2, have been isolated, together with four known hydroxamates, desferrioxamine D1 3, desferrioxamine B 4, desoxy-nocardamine 5 and nocardamine 6, and a diketopiperazine (DKP) 7. The structures of 1–7 were characterized by the analysis of HRESIMS and 1D and 2D NMR data, as well as by comparison with the relevant literature. Three new dehydroxy desferrioxamine derivatives 8–10 were tentatively identified in the molecular network of K. speibonae strain SK5 extracts, and structures were proposed based on their MS/MS fragmentation patterns. A plausible spb biosynthetic pathway was proposed. To the best of our knowledge, this is the first report of the isolation of desferrioxamines from the actinobacterial genus Kribbella.

Development of a Kribbella-specific isolation medium and description of Kribbella capetownensis sp. nov. and Kribbella speibonae sp. nov., isolated from soil.

Two actinobacterial strains were isolated from samples collected from the University of Cape Town, South Africa. A third actinobacterial strain was isolated from soil collected in the town of Stellenbosch, South Africa, using a newly-developed Kribbella-selective medium. Analysis of the 16S rRNA genes showed that the three strains belonged to the genus Kribbella. A multilocus sequence analysis using the concatenated gene sequences of the gyrB, rpoB, relA, recA and atpD genes showed that strains YM55T and SK5 were most closely related to the type strains of Kribbella sindirgiensis and Kribbella soli, while strain YM53T was most closely related to the type strain of Kribbella pittospori. Digital DNA-DNA hybridisation and Average Nucleotide Identity (ANI) analyses showed that strains YM55T and SK5 belong to the same genomic species (OrthoANI value = 98.4%), but are distinct from the genomic species represented by the type strains of K. sindirgiensis (OrthoANI values < 95.6%) and K. soli (OrthoANI values < 91.4%). Strain YM53T is distinct from the genomic species represented by the type strain of K. pittospori (OrthoANI value = 94.0%). Phenotypic comparisons showed that strains YM55T and SK5 are distinct from the type strains of K. sindirgiensis and K. soli and that strain YM53T is distinct from the type strain of K. pittospori. Strains YM53T and YM55T are thus presented as the type strains of novel species, for which the names Kribbella capetownensis sp. nov. (= DSM 29426T = NRRL B-65062T) and Kribbella speibonae sp. nov. (= DSM 29425T = NRRL B-59161T), respectively, are proposed.

Kribbella jiaozuonensis sp. nov., a novel actinomycete isolated from soil.

A novel actinobacterium, designated strain NEAU-THZ27T, was isolated from soil collected from the Cornel peak in Jiaozuo, Henan Province, PR China and characterized using a polyphasic approach. Morphological and chemotaxonomic characteristics of the strain coincided with those of members of the genusKribbella. The results of 16S rRNA gene sequence analysis showed that strain NEAU-THZ27T belongs to the genus Kribbella and was most closely related to Kribbella podocarpi YPL1T (98.96 %), Kribbella karoonensis Q41T (98.89 %), Kribbella aluminosa HKI 0478T (98.86%) and Kribbella hippodromi S1.4T (98.85 %), similarities to other type strains of species of the genus Kribbella were found to be less than 98.7 %. Phylogenetic analyses using the 16S rRNA gene sequence and multilocus sequence analysis using the concatenated gene sequences of the gyrB, rpoB, recA, relA and atpD genes all showed that the strain formed a separate branch in the genus Kribbella. The cell wall contained ll-diaminopimelic acid as the major diamino acid and the whole-cell hydrolysates were ribose and glucose. The major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol and phosphatidylinositol. The predominant menaquinone was MK-9(H4). Major fatty acids were iso-C16 : 0, iso-C14 : 0 and anteiso-C15 : 0, these chemotaxonomic data supported the affiliation of strain NEAU-THZ27T to the genus Kribbella. The DNA G+C content was 68.0 mol%. Furthermore, the strain could be clearly distinguished by concatenated gene genetic distances, the combination of DNA-DNA hybridization results and some phenotypic characteristics. Therefore, it is proposed that strain NEAU-THZ27T represents a novel species of the genus Kribbella, for which the name Kribbella jiaozuonensis sp. nov. is proposed. The type strain is NEAU-THZ27T (=CGMCC 4.7504T=DSM 105535T).

Kribbella turkmenica sp. nov., isolated from the Karakum Desert.

A novel actinobacterial strain, designated 16K104T, was isolated from desert soil collected from the Karakum Desert and characterized using a polyphasic approach to clarify its taxonomic position. Strain 16K104T was found to have chemotaxonomic and morphological properties consistent with classification in the genus Kribbella. The strain shared the highest 16S rRNA gene sequence similarity with Kribbella albertanoniae BC640T (99.2 %), and formed a branch with Kribbella antibiotica YIM 31530T in the 16S rRNA gene phylogenetic tree. Multilocus sequence analysis (MLSA) using five housekeeping genes (gyrB, rpoB, relA, recA and atpD) for comparing the strain with all Kribbella type strains showed that the MLSA distances of strain 16K104T to the closely related type strains of the genus were much higher than the 0.04 threshold. The organism was found to contain ll-diaminopimelic acid as the diagnostic diamino acid in the cell-wall peptidoglycan. The whole-cell sugars were identified as ribose and glucose. The major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol and phosphatidylinositol. The predominant menaquinone was MK-9(H4). The major fatty acids were iso-C16 : 0, anteiso-C15:0, iso-C15 : 0 and iso-C17 : 0. The results of digital DNA-DNA hybridization and average nucleotide identity analyses, in addition to MLSA phylogenetic distances, confirmed that the strain represents a novel species of the genus Kribbella, for which the name Kribbella turkmenica sp. nov. is proposed. The type strain is 16K104T (=JCM 32914T=KCTC 49224T).

Kribbella monticola sp. nov., a novel actinomycete isolated from soil.

A novel actinobacterium, designated strain NEAU-SW521T, was isolated from soil collected from Xianglu Mountain, Heilongjiang province, north PR China. The results of analysis of the 16S rRNA gene indicated that NEAU-SW521T represented a member of the genus Kribbella. The results of phylogenetic analyses using the 16S rRNA gene and multilocus sequence analysis using the concatenated gene sequences of the gyrB, rpoB, relA, recA and atpD genes all indicated that the strain formed a clade with Kribbella alba DSM 15500T (99.16 %), Kribbella ginsengisoli JCM 16928T (98.96 %), Kribbella catacumbae JCM 14968T (98.82 %), Kribbella sancticallisti JCM 14969T (98.62 %), Kribbella qitaiheensis NEAU-GQTH2-3T (98.61 %) and Kribbella koreensis JCM 10977T (98.47 %). The cell wall contained ll-diaminopimelic acid as the major diamino acid and the whole-cell hydrolysates were ribose, glucose and galactose. The major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol and an unidentified phospholipid. The predominant menaquinone was MK-9(H4). Major fatty acids were iso-C16 : 0 and anteiso-C15 : 0. These chemotaxonomic data supported the affiliation of NEAU-SW521T to the genus Kribbella. The DNA G+C content was 67.8 mol%. Furthermore, the strain could be clearly distinguished by concatenated gene genetic distances, the combination of DNA-DNA hybridization results and some phenotypic characteristics. Therefore, it is proposed that NEAU-SW521T represents a novel species of the genus Kribbella, for which the name Kribbellamonticola sp. nov. is proposed. The type strain is NEAU-SW521T (=CGMCC 4.7465T=DSM 105770T).

Kribbella podocarpi sp. nov., isolated from the leaves of a yellowwood tree (Podocarpus latifolius).

An endophytic actinobacterial strain was isolated from a yellowwood tree growing on the slope of Devil's Peak, Cape Town, South Africa. Analysis of the 16S rRNA gene showed that the strain belongs to the genus Kribbella. Phylogenetic analyses using the 16S rRNA gene and multilocus sequence analysis using the concatenated gene sequences of the gyrB, rpoB, relA, recA and atpD genes showed that strain YPL1T is closely related to the type strains of Kribbella karoonensis and Kribbella shirazensis. DDH experiments showed that strain YPL1T is a distinct genomic species from its close phylogenetic relative, K. karoonensis Q41T. Physiological comparisons further showed that strain YPL1T is phenotypically distinct from the type strains of Kribbella jejuensis, Kribbella aluminosa, K. karoonensis, K. shirazensis and Kribbella swartbergensis. Strain YPL1T is thus presented as the type strain of a novel species, for which the name Kribbella podocarpi sp. nov. (=DSM 29424T=NRRL B-65063T), is proposed.

Kribbella sindirgiensis sp. nov. isolated from soil

A Kribbella strain FSN23T was isolated from soil sample which was collected from Caygoren Dam lakeside located in Sındırgı, Turkey. The isolate was investigated using a polyphasic approach consisting of numeric, chemotaxonomic and molecular analysis. The isolate indicated chemotaxonomic, morphological and phylogenetic properties associated with members of the genus Kribbella. Phylogenetic analysis based on the 16S rRNA sequence of the strain demonstrated that the strain forms a subclade with K. aluminosa HKI 0478T and K. jejuensis HD9T. The organism formed an extensively branched substrate and aerial hyphae which generated spiral chains of spores with smooth surfaces. The cell wall contained LL-diaminopimelic acid, and the whole cell sugars were glucose and ribose along with trace amounts of mannose. The polar lipids were identified as phosphatidylglycerol, diphosphatidylglycerol, four unidentified lipids and five unidentified polar lipids. The predominant menaquinone was MK-9(H4). The major cellular fatty acids were anteiso-C15:0 and iso-C16:0. Polyphasic taxonomy properties confirm that strain FSN23T represents a novel Kribbella taxon distinguished from closely related type strains. Hence, strain FSN23T (=KCTC 29220T=DSM 27082T) is proposed as the type strain of a novel species with the name Kribbella sindirgiensis sp. nov.

Kribbella soli sp. nov., isolated from soil.

A novel actinobacterial strain, designated FMN22T, was isolated from soil and characterised using a polyphasic approach. Strain FMN22T showed high 16S rRNA gene sequence similarity to Kribbella karoonensis Q41T (99.3%), Kribbella shirazensis UTMC 693T (99.0%), Kribbella aluminosa HKI 0478T (98.9%) and Kribbella hippodromi S1.4T (98.6%). Phylogenetic analysis using the 16S rRNA and concatenated gene (gyrB, rpoB, relA, recA and atpD) sequences showed that strain FMN22T is closely related to the type strains of K. karoonensis DSM 17344T, K. shirazensis UTMC 693T, K. aluminosa HKI 0478T, K. hippodromi S1.4T, Kribbella jejuensis HD9T and Kribbella solani DSA1T. Based on concatenated gene genetic distances analysis, strain FMN22T is distinct from all Kribbella type strains. DNA-DNA hybridization experiments with closely related type strains, were found to be 59.2±2.4, 54.8±2.1, 16.4±2.3 and 38.6±2.5%, relatedness to K. karoonensis DSM 17344T, K. shirazensis DSM 45490T, K. aluminosa DSM 18824T and K. jejuensis DSM 17305T, respectively. The cell wall peptidoglycan contained LL-diaminopimelic acid, and whole cell sugars were glucose, mannose and ribose. The predominant menaquinone was MK-9(H4). The major phospholipids are diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and phosphatidylinositol. Major fatty acids are anteiso-C15:0 and iso-C16:0. These chemotaxonomic traits are in good agreement with those known for representatives of the genus Kribbella. A combination of DNA-DNA hybridization results and phenotypic properties demonstrated that strain FMN22T can be clearly distinguished from all close phylogenetic relatives. Therefore, strain FMN22T (=DSM 27132T=KCTC 29219T) is considered to be the type strain of a novel species of the genus Kribbella, for which the name Kribbella soli is proposed.

Kribbella pittospori sp. nov., an endophytic actinobacterium isolated from the surface-sterilized stem of an Australian native apricot tree, Pittosporum angustifolium.

An endophytic actinobacterium, strain PIP 158T, was isolated from the stem of a native apricot tree (Pittosporum angustifolium) collected from the grounds of Flinders University, Adelaide, Australia. As a result of a polyphasic taxonomic study, this strain was identified as a member of the genus Kribbella. This strain was a Gram-stain-positive, aerobic actinobacterium with well-developed substrate mycelia which were non-motile and with hyphae fragmenting into short to elongated rod-like elements. Phylogenetic evaluation based on 16S rRNA gene sequence analysis placed this isolate in the family Nocardioidaceae, being most closely related to Kribbella sandramycini ATCC 39419T and Kribbella albertanoniae BC640T which share a similarity of 99. 26 and 99.18 % with Kribbella hippodromi S1.4T, respectively. Chemotaxonomic data including cell-wall components, major menaquinones and major fatty acids confirmed the affiliation of strain PIP 158T to the genus Kribbella. The results of the phylogenetic analysis, including physiological and biochemical studies in combination with DNA-DNA hybridization, allowed the genotypic and phenotypic differentiation of strain PIP 158T from the closest related species with validly published names. The name proposed for the novel species is Kribbella pittospori sp. nov. The type strain is PIP 158T (=DSM 23717T=NRRL B-24813T).

Kribbella mirabilis sp. nov., isolated from rhizosphere soil of a herbaceous plant, Mirabilis jalapa L.

Strain XMU 706(T), isolated from the rhizosphere soil of a herbaceous plant, Mirabilis jalapa L., collected from Xiamen City, China, was characterized using a polyphasic approach to clarify its taxonomic position. Strain XMU 706(T) shared the highest 16S rRNA gene sequence similarity with Kribbella antibiotica YIM 31530(T) (97.2%), and formed a distinct branch in the subclade of the genus Kribbella in the 16S rRNA gene phylogenetic tree. The genetic distances of gyrase subunit B gene (gyrB) sequence between strain XMU 706(T) and other species of the genus Kribbella ranged from 0.045 to 0.116, greater than the threshold value of 0.014 for species delineation of this genus. DNA-DNA hybridization experiments gave a DNA-DNA relatedness value of 34.82 ± 6.31% between strain XMU 706(T) and K. antibiotica YIM 31530(T). The chemotaxonomic properties further supported the assignment of strain XMU 706(T) to the genus Kribbella. ll-Diaminopimelic acid was the diagnostic amino acid in the cell-wall peptidoglycan and cell hydrolysates contained ribose and glucose. The major menaquinone was MK-9(H4). The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and other unidentified phospholipids and lipids. The major fatty acids of the strain were anteiso-C15 : 0 and iso-C15 : 0, and the G+C content of the genomic DNA was 67.3 mol%. Based on the results of phylogenetic analysis, phenotypic and genotypic characterization, strain XMU 706(T) represents a novel species of the genus Kribbella, for which the name Kribbella mirabilis sp. nov. is proposed. The type strain is XMU 706(T) ( = KCTC 29676(T) = MCCC 1K00429(T)).

Kribbella qitaiheensis sp. nov., a novel actinomycete isolated from soil.

A novel nocardioform actinomycete, designated strain NEAU-GQTH2-3(T), was isolated from muddy soil collected from a stream in Qitaihe, Heilongjiang Province, northeast China and characterized using a polyphasic approach. Phylogenetic analysis based on the 16S rRNA gene sequence demonstrated that the organism should be assigned to the genus Kribbella and forms a clade with Kribbella catacumbae JCM 14968(T) (99.2% sequence similarity), Kribbella koreensis JCM 10977(T) (99.1%), Kribbella ginsengisoli JCM 16928(T) (98.6%) and Kribbella sancticallisti JCM 14969(T) (98.4%), although with low bootstrap support. Morphological and chemotaxonomic properties of the isolate are in agreement with the description of the genus Kribbella. Chemotaxonomic characteristics include LL-diaminopimelic acid in the cell-wall peptidoglycan; glucose and ribose as the characteristic whole-cell hydrolysates; diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylinositol, a glycerolipid and an unidentified phospholipid as the predominant polar lipids; the major menaquinones MK-9(H4) and MK-9(H2); as well as iso-C15:0, iso-C16:0 and C17:1 ω7c being the predominant fatty acid components. Mycolic acids were not detected. Furthermore, the strain could be clearly distinguished by the combination of DNA-DNA hybridization results and some phenotypic characteristics from the closest phylogenetic relatives. Therefore, it is proposed that strain NEAU-GQTH2-3(T) represents a novel species of the genus Kribbella, for which the name Kribbella qitaiheensis sp. nov. is proposed. The type strain is NEAU-GQTH2-3(T) (=CGMCC 4.7215(T)=JCM 30343(T)).

Multilocus sequence analysis of the actinobacterial genus Kribbella

Multilocus sequence analysis (MLSA) was used to refine the phylogenetic analysis of the genus Kribbella, which currently contains 17 species with validly-published names. Sequences were obtained for the 16S rRNA, gyrB, rpoB, recA, relA and atpD genes for 16 of the 17 type strains of the genus plus seven non-type strains. A five-gene concatenated sequence of 4099 nt was used to examine the phylogenetic relationships between the species of the genus Kribbella. Using the concatenated sequence of the gyrB-rpoB-recA-relA and atpD genes, most Kribbella type strains can be distinguished by a genetic distance of >0.04. Each single-gene tree had an overall topology similar to that of the concatenated sequence tree. The single-gene relA tree, used here for the first time in MLSA of actinobacteria, had good bootstrap support, comparable to the rpoB and atpD gene trees, which had topologies closest to that of the concatenated sequence tree. This illustrates that relA is a useful addition in MLSA studies of the genus Kribbella. We propose that concatenated gyrB-rpoB-recA-relA-atpD gene sequences be used for examining the phylogenetic relationships within the genus Kribbella and for determining the closest phylogenetic relatives to be used for taxonomic comparisons.

Novel teichulosonic acid from cell walls of some representatives of the genus Kribbella

Cell walls of each of five bacterial strains belonging to the genus Kribbella (family Nocardioidaceae, order Actinomycetales) contain a neutral polysaccharide (mannan) and teichulosonic acid of novel structure in different proportions. The novel teichulosonic acid found in strains VKM Ac-2500, VKM Ас-2568, VKM Ас-2572, and VKM Ас-2575 is a heteropolymer with an irregular structure where fragments I (predominant) alternate with fragments II (minor):▪The teichulosonic acid from Kribbella sp. VKM Ac-2527 has in general a structure similar to that above with the exception that the Pse residue is randomly glycosylated at O-4 with β-l-Rhap (along with α-d-Galp3OMe or α-d-Galp2,3OMe). The strain VKM Ac-2572 contained additionally teichuronic acid with the disaccharide repeating unit consisted of aminomannuronic acid and 2,3-diacetamido-2,3-dideoxy-α-glucopyranose. The mannan, a polysaccharide common to all of the strains, is built of (1→6)-linked α-d-mannopyranose substituted with α-d-mannopyranose at O-2. The structures of all the glycopolymers were established by a combination of chemical and NMR spectroscopic methods.

Complete genome sequence of Kribbella flavida type strain (IFO 14399T)

The genus Kribbella consists of 15 species, with Kribbella flavida (Park et al. 1999) as the type species. The name Kribbella was formed from the acronym of the Korea Research Institute of Bioscience and Biotechnology, KRIBB. Strains of the various Kribbella species were originally isolated from soil, potato, alum slate mine, patinas of catacombs or from horse racecourses. Here we describe the features of K. flavida together with the complete genome sequence and annotation. In addition to the 5.3 Mbp genome of Nocardioides sp. JS614, this is only the second completed genome sequence of the family Nocardioidaceae. The 7,579,488 bp long genome with its 7,086 protein-coding and 60 RNA genes and is part of the Genomic Encyclopedia of Bacteria and Archaea project.

Phylogenetic analysis of the genus Kribbella based on the gyrB gene: proposal of a gyrB-sequence threshold for species delineation in the genus Kribbella

Given the advances in molecular biology, many microbial taxonomists feel that a sequencing based method should be developed that can replace DNA-DNA hybridisation for species delineation. The potential of the gyrB gene to be used for phylogenetic studies has been investigated within a number of actinobacterial genera, including Gordonia, Micromonospora and the whorl-forming Streptomyces species. This study aimed to determine whether the gyrB gene can discriminate between type strains of the genus Kribbella. Previous studies, in the genus Micromonospora, have found that a gyrB-based genetic distance of 0.014 correlates to a DNA relatedness of 70% and that those strains with a genetic distance of greater than 0.014 are likely to be distinct species. In this study, the gyrB-based genetic distances between Kribbella type strains were found to range from 0.0164 to 0.1495, supporting the use of the 0.014 genetic-distance value as the threshold for species delineation within this genus. Phylogenetic analysis based on the gyrB gene had improved resolution (longer branch lengths) compared to that based on the 16S rRNA gene sequence. Based on this study, the gyrB gene can be used to distinguish between Kribbella type strains. Furthermore, it is proposed that a 390-nucleotide sequence of the gyrB gene of a Kribbella isolate is sufficient to assess whether it is likely to represent a new species, before time and effort is invested in polyphasic taxonomic characterisation of the isolate.

New cell wall glycopolymers of the representatives of the genus Kribbella

Each of the cell walls of four representatives of the genus Kribbella (order Actinomycetales; suborder Propionibacterineae; family Nocardioidaceae) contains a neutral polysaccharide and an acidic polysaccharide with unusual structures. Common to all four strains studied is a mannan with the following repeating unit: ▪ In the cell wall of the strain VKM Ac-2541, a teichulosonic acid was identified with a monosaccharide component that has not hitherto been found in Gram-positive bacteria, viz., pseudaminic acid, and an unusual linkage type in the polymeric chain, ▪ where R = Н (45%), α- d-Gal p3OMe (37%) or α- d-Gal p2,3OMe (18%). The anionic cell wall components of three other strains are represented by teichuronic acids with a rare constituent, viz., a diaminosugar, 2,3-diacetamido-2,3-dideoxyglucopyranose. The structures of their repeating units differ in the nature of the acidic components: →4)-β- d-Man p2,3NAcA-(1→6)-α- d-Glc p2,3NAc-(1→ (VKM Ас-2538 and VKM Ас-2540) and →4)-β- d-Man pNAcA-(1→6)-α- d-Glc p2,3NAc-(1→ (VKM Ас-2539). The structures of all the glycopolymers were established by chemical and NMR spectroscopic methods; they are identified in Gram-positive bacteria for the first time.

Kribbella ginsengisoli sp. nov., isolated from soil of a ginseng field

A Gram-positive, non-spore-forming, aerobic bacterium, designated Gsoil 001(T), was isolated from the soil of a ginseng field in Pocheon province, South Korea. On the basis of 16S rRNA gene sequence analysis, strain Gsoil 001(T) was shown to belong to the genus Kribbella. The closest phylogenetic relatives were Kribbella koreensis LM 161(T) (99.0 % 16S rRNA gene sequence similarity), Kribbella flavida KACC 20248(T) (98.8 %) and Kribbella alba (98.8%). Lower similarity (98.4-96.9 %) was found with the other recognized species of the genus Kribbella. The major quinone was MK-9(H(4)), the major fatty acids were anteiso-C(15 : 0) and iso-C(16 : 0) and the major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol and phosphatidylinositol. The cell-wall peptidoglycan contained ll-2,6-diaminopimelic acid. These chemotaxonomic data and the high genomic DNA G+C content (66.3 mol%) supported the affiliation of strain Gsoil 001(T) to the genus Kribbella. The results of physiological and biochemical tests differentiated strain Gsoil 001(T) genotypically and phenotypically from the Kribbella species with validly published names. Therefore, this isolate represents a novel species, for which the name Kribbella ginsengisoli sp. nov. is proposed, with the type strain Gsoil 001(T) (=KCTC 19134(T) =DSM 17941(T)).