Blastococcus brunescens sp. nov., a member of the Geodermatophilaceae isolated from sandstone collected from the Sahara Desert in Tunisia.

The taxonomic position of strain BMG 8361T, isolated from sandstone collected in the Sahara Desert of Southern Tunisia, was refined through a polyphasic taxonomic investigation. Colonies of BMG 8361T were pale-orange coloured, irregular with a dry surface and produced a diffusible pink or brown pigment depending on media. The Gram-positive cells were catalase-positive and oxidase-negative. The strain exhibited growth at 10-40 °C and pH values ranging from 5.5 to 9.0, with optima at 28-35 °C and pH 6.5-8.0. Additionally, BMG 8361T demonstrated the ability to grow in the presence of up to 1 % NaCl (w/v) concentration. The peptidoglycan of the cell wall contained meso-diaminopimelic acid, glucose, galactose, xylose, ribose, and rhamnose. The predominant menaquinones consisted of MK-9(H4) and MK-9. The main polar lipids were phosphatidylcholine, phosphatidylinositol, glycophosphatidylinositol, diphosphatidylglycerol, phosphatidylethanolamine, and two unidentified lipids. Major cellular fatty acids were iso-C16 : 0, iso-C16 : 1 h, and C17 : 1 ω8c. Phylogenetic analyses based on both the 16S rRNA gene and whole-genome sequences assigned strain BMG 8361T within the genus Blastococcus. The highest pairwise sequence similarity observed in the 16S rRNA gene was 99.5 % with Blastococcus haudaquaticus AT 7-14T. However, when considering digital DNA-DNA hybridization and average nucleotide identity, the highest values, 48.4 and 86.58 %, respectively, were obtained with Blastococcus colisei BMG 822T. These values significantly undershoot the recommended thresholds for establishing new species, corroborating the robust support for the distinctive taxonomic status of strain BMG 8361T within the genus Blastococcus. In conjunction with the phenotyping results, this compelling evidence leads to the proposal of a novel species we named Blastococcus brunescens sp. nov. with BMG 8361T (=DSM 46845T=CECT 8880T) as the type strain.

Blastococcus carthaginiensis sp. nov., isolated from a monument sampled in Carthage, Tunisia.

A comprehensive polyphasic investigation was conducted to elucidate the taxonomic position of an actinobacterium, designated BMG 814T, which was isolated from the historic ruins of Carthage city in Tunisia. It grew as pink-orange pigmented colonies and displayed versatile growth capabilities, thriving within a temperature range of 20-40 °C, across a pH spectrum ranging from pH 5.5 to 10 and in the presence of up to 4 % NaCl. Chemotaxonomic investigations unveiled specific cell components, including diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, glycophosphatidylinositol, an unidentified aminoglycophospholipid, six unidentified aminolipids, two unidentified phospholipids and one unidentified lipid in its polar lipid profile. Furthermore, galactose, glucose and ribose were identified as the primary cell-wall sugars. Major menaquinones identified were MK-9(H4), MK-9(H2) and MK-9, while major fatty acids comprised iso-C15 : 0, iso-C16 : 0, C17 : 1 ω8c and C18 : 1 ω9c. Through phylogenetic analysis based on the 16S rRNA gene sequence, the strain was positioned within the genus Blastococcus, with Blastococcus capsiensis BMG 804T showing the closest relationship (99.1 %). In light of this, draft genomes for both strains, BMG 814T and BMG 804T, were sequenced in this study, and comparative analysis revealed that strain BMG 814T exhibited digital DNA-DNA hybridization and average nucleotide identity values below the recommended thresholds for demarcating new species with all available genomes of type strains of validly names species. Based on the polyphasic taxonomy assessment, strain BMG 814T (=DSM 46848T=CECT 8878T) was proposed as the type strain of a novel species named Blastococcus carthaginiensis sp. nov.

Rare Halophilic Nocardiopsis from Algerian Saharan Soils as Tools for Biotechnological Processes in Pharmaceutical Industry.

The Sahara Desert, one of the most extreme ecosystems in the planet, constitutes an unexplored source of microorganisms such as mycelial bacteria. In this study, we investigated the diversity of halophilic actinobacteria in soils collected from five regions of the Algerian Sahara. A total of 23 halophilic actinobacterial strains were isolated by using a humic-vitamin agar medium supplemented with 10% NaCl. The isolated halophilic strains were subjected to taxonomic analysis using a polyphasic approach, which included morphological, chemotaxonomic, physiological (numerical taxonomy), and phylogenetic analyses. The isolates showed abundant growth in CMA (complex medium agar) and TSA (tryptic soy agar) media containing 10% NaCl, and chemotaxonomic characteristics were consistent with their assignment to the genus Nocardiopsis. Analysis of the 16S rRNA sequence of 23 isolates showed five distinct clusters and a similarity level ranging between 98.4% and 99.8% within the Nocardiopsis species. Comparison of their physiological characteristics with the nearest species showed significant differences with the closely related species. Halophilic Nocardiopsis isolated from Algerian Sahara soil represents a distinct phyletic line suggesting a potential new species. Furthermore, the isolated strains of halophilic Nocardiopsis were screened for their antagonistic properties against a broad spectrum of microorganisms by the conventional agar method (agar cylinders method) and found to have the capacity to produce bioactive secondary metabolites. Except one isolate (AH37), all isolated Nocardiopsis showed moderate to high biological activities against Pseudomonas syringae and Salmonella enterica, and some isolates showed activities against Agrobacterium tumefaciens, Serratia marcescens, and Klebsiella pneumoniae. However, no isolates were active against Bacillus subtilis, Aspergillus flavus, or Aspergillus niger. The obtained finding implies that the unexplored extreme environments such as the Sahara contain many new bacterial species as a novel drug source for medical and industrial applications.

Frankia colletiae sp. nov., a nitrogen-fixing actinobacterium isolated from Colletia cruciata.

A nitrogen-fixing actinobacterium strain (Cc1.17T) isolated from a root nodule of Colletia cruciata was subjected to polyphasic taxonomic studies. The strain was characterized by the presence of meso-diaminopimelic acid in its peptidoglycan, galactose, glucose, mannose, rhamnose, ribose and xylose as cell-wall sugars, phosphatidylinositol, diphosphatidylglycerol, glycophospholipids, phosphatidylglycerol, glycophospholipid and uncharacterized lipids as its polar lipids, and C16 : 0, iso-C16 : 0, C17 : 1 ω9 and C18 : 1 ω9 as major fatty acids (>10 %). Strain Cc1.17T showed 16S rRNA gene sequence similarities of 97.4-99.8 % to validly named Frankia species. Phylogenetic trees based on 16S rRNA gene and genome sequences placed strain Cc1.17T in a new lineage within the genus Frankia. Digital DNA-DNA hybridization and average nucleotide identity values between strain Cc1.17T and its closest phylogenomic neighbours were well below the thresholds recommended for prokaryotic species delineation. Therefore, strain Cc1.17T (=DSM 43829T=CECT 9313T) merits recognition as the type strain of a new species for which the name Frankia colletiae sp. nov. is proposed.

Novel species of Frankia, Frankia gtarii sp. nov. and Frankia tisai sp. nov., isolated from a root nodule of Alnus glutinosa.

The status of four Frankia strains isolated from a root nodule of Alnus glutinosa was established in a polyphasic study. Taxogenomics and phenotypic features show that the isolates belong to the genus Frankia. All four strains form extensively branched substrate mycelia, multilocular sporangia, vesicles, lack aerial hyphae, but contain meso-diaminopimelic acid as the diamino acid of the peptidoglycan, galactose, glucose, mannose, ribose, xylose and traces of rhamnose as cell wall sugars, iso-C16:0 as the predominant fatty acid, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol as the major polar lipids, have comparable genome sizes to other cluster 1, Alnus-infective strains with structural and accessory genes associated with nitrogen fixation. The genome sizes of the isolates range from 7.0 to 7.7 Mbp and the digital DNA G + C contents from 71.3 to 71.5 %. The four sequenced genomes are rich in biosynthetic gene clusters predicted to express for novel specialized metabolites, notably antibiotics. 16S rRNA gene and whole genome sequence analyses show that the isolates fall into two lineages that are closely related to the type strains of Frankia alni and Frankia torreyi. All of these taxa are separated by combinations of phenotypic properties and by digital DNA:DNA hybridization scores which indicate that they belong to different genomic species. Based on these results, it is proposed that isolates Agncl-4T and Agncl-10, and Agncl-8T and Agncl-18, be recognised as Frankia gtarii sp. nov. and Frankia tisai sp. nov. respectively, with isolates Agncl-4T (=DSM 107976T = CECT 9711T) and Agncl-8T (=DSM 107980T = CECT 9715T) as the respective type strains.

Genotype-phenotype correlations within the Geodermatophilaceae.

The integration of genomic information into microbial systematics along with physiological and chemotaxonomic parameters provides for a reliable classification of prokaryotes. In silico analysis of chemotaxonomic traits is now being introduced to replace characteristics traditionally determined in the laboratory with the dual goal of both increasing the speed of the description of taxa and the accuracy and consistency of taxonomic reports. Genomics has already successfully been applied in the taxonomic rearrangement of Geodermatophilaceae (Actinomycetota) but in the light of new genomic data the taxonomy of the family needs to be revisited. In conjunction with the taxonomic characterisation of four strains phylogenetically located within the family, we conducted a phylogenetic analysis of the whole proteomes of the sequenced type strains and established genotype-phenotype correlations for traits related to chemotaxonomy, cell morphology and metabolism. Results indicated that the four isolates under study represent four novel species within the genus Blastococcus. Additionally, the genera Blastococcus, Geodermatophilus and Modestobacter were shown to be paraphyletic. Consequently, the new genera Trujillonella, Pleomorpha and Goekera were proposed within the Geodermatophilaceae and Blastococcus endophyticus was reclassified as Trujillonella endophytica comb. nov., Geodermatophilus daqingensis as Pleomorpha daqingensis comb. nov. and Modestobacter deserti as Goekera deserti comb. nov. Accordingly, we also proposed emended descriptions of Blastococcus aggregatus, Blastococcus jejuensis, Blastococcus saxobsidens and Blastococcus xanthilyniticus. In silico chemotaxonomic results were overall consistent with wet-lab results. Even though in silico discriminatory levels varied depending on the respective chemotaxonomic trait, this approach is promising for effectively replacing and/or complementing chemotaxonomic analyses at taxonomic ranks above the species level. Finally, interesting but previously overlooked insights regarding morphology and ecology were revealed by the presence of a repertoire of genes related to flagellum synthesis, chemotaxis, spore production and pilus assembly in all representatives of the family. A rich carbon metabolism including four different CO2 fixation pathways and a battery of enzymes able to degrade complex carbohydrates were also identified in Blastococcus genomes.

Genome-based reclassification of Actinopolyspora righensis Meklat et al. 2013 as a later heterotypic synonym of Actinopolyspora lacussalsi Guan et al. 2013 and description of Actinopolyspora lacussalsi subsp. lacussalsi subsp. nov. and Actinopolyspora lacussalsi subsp. righensis subsp. nov.

A genome led phylophasic study was designed to determine the taxonomic status of a strain, DSM 45956, recovered from a Saharan desert soil. A wealth of taxonomic data, including average nucleotide identity and DNA:DNA hybridization (DDH) values, showed that the isolate and the type strains of Actinopolyspora lacussalsi and Actinopolyspora righensis belong to the same species. Consequently, it is proposed that A. righensis is a heterotypic synonym of A. lacussalsi. Similarly, DDH values and associated phenotypic data show that A. lacussalsi contains two subspecies, A. lacussalsi subsp. lacussalsi and A. lacussalsi subsp. righensis which includes isolate DSM 45956.

Shewanella azerbaijanica sp. nov. a novel aquatic species with high bioremediation abilities.

A novel Gram-negative, facultative anaerobic, rod-shaped, and non-motile bacterium with bio-degradation potential of polycyclic aromatic hydrocarbons (PAHs) and uranium bio-reduction, designated as RCRI7T, was isolated from Qurugöl Lake water near Tabriz city. Strain RCRI7T can grow in the absence of NaCl and tolerates up to 3% NaCl (optimum, 0-0.5%), at the temperature range of 4-45 °C (optimum, 30 °C) and a pH range of 6-9 (optimum, pH 7 ± 0.5). Results of phylogenetic analysis based on 16S rRNA gene sequence indicated that strain RCRI7T is affiliated with the genus Shewanella, most closely related to Shewanella xiamenensis S4T (99.1%) and Shewanella putrefaciens JCM 20190T (98.9%). The genomic DNA G+C content of strain RCRI7T is 41 mol%. The major fatty acids are C16:1ω9c, C18:1ω9c and iso-C17:1ω5c. The OrthoANI and ANIb values between RCRI7T and Shewanella xiamenensis S4T were 87.4% and 87.7%, and between RCRI7T and Shewanella putrefaciens JCM 20190T were 79.5% and 79.7%, respectively. Strain RCRI7T displayed dDDH values of 30.2% and 39.8% to Shewanella xiamenensis S4T and Shewanella putrefaciens JCM 20190T, respectively. The major polar lipids include phosphatidylglycerol (PG) and phosphatidylethanolamine (PE). The respiratory quinone is Q8. Based on the polyphasic evidence presented in this paper, strain RCRI7T is considered to represent a novel species, with bioremediation potential, in the genus Shewanella, for which the name Shewanella azerbaijanica sp. nov. is proposed. The type strain is RCRI7T (= JCM 17276T) (= KCTC 62476T).

Blastococcus tunisiensis sp. nov., isolated from limestone collected in Tunisia.

A new actinobacterium strain, designated BMG 823T, was isolated from a limestone sample collected in Tunisia. Its taxonomic position was scrutinized using a polyphasic approach. Colonies of strain BMG 823T were pink orange-coloured, regular and had a moist surface. Cells are Gram-stain-positive, catalase-negative and oxidase-negative. The strain grew at pH 5.5-9, 10-40 °C and in presence of up to 4 % NaCl (w/v). Chemotaxonomically, strain BMG 823T was characterized by cell-wall type III containing meso-diaminopimelic acid as diamino acid, glucose, ribose and rhamnose as whole-cell sugars, MK-9(H4) as predominant menaquinone, and phosphatidylcholine, diphosphadidylglycerol, phosphatidethanolamine, phosphatidylcholine, phosphatidylinositol, unidentified glycolipid, unidentified aminophospholipids and unidentified glycophospholipid as major polar lipids. The fatty acid profile consisted of iso-C16 : 0 and iso-C17 : 1 ω9. Phylogenetic trees based on 16S rRNA gene and genome sequences placed strain BMG 823T within the genus Blastococcus and separated it from all type strains of validly published species. Comparison of 16S rRNA gene sequence similarity, digital DNA-DNA hybridization and average nucleotide identity indicated that strain BMG 823T was most closely related to Blastococcus litoris DSM 106127T and Blastococcus colisei BMG 822T with pairwise values well below the species differentiation thresholds. The distinct phenotypic and genotypic features of strain BMG 823T (=DSM 46838T=CECT 8881T) within the genus Blastococcus warrant its recognition as the type strain for the new species for which we propose the name Blastococcus tunisiensis sp. nov.

Expanding the genomic encyclopedia of Actinobacteria with 824 isolate reference genomes.

The phylum Actinobacteria includes important human pathogens like Mycobacterium tuberculosis and Corynebacterium diphtheriae and renowned producers of secondary metabolites of commercial interest, yet only a small part of its diversity is represented by sequenced genomes. Here, we present 824 actinobacterial isolate genomes in the context of a phylum-wide analysis of 6,700 genomes including public isolates and metagenome-assembled genomes (MAGs). We estimate that only 30%-50% of projected actinobacterial phylogenetic diversity possesses genomic representation via isolates and MAGs. A comparison of gene functions reveals novel determinants of host-microbe interaction as well as environment-specific adaptations such as potential antimicrobial peptides. We identify plasmids and prophages across isolates and uncover extensive prophage diversity structured mainly by host taxonomy. Analysis of >80,000 biosynthetic gene clusters reveals that horizontal gene transfer and gene loss shape secondary metabolite repertoire across taxa. Our observations illustrate the essential role of and need for high-quality isolate genome sequences.

Corrigendum: Genotype-phenotype correlations within the Geodermatophilaceae.

[This corrects the article DOI: 10.3389/fmicb.2022.975365.].

Thermococcus bergensis sp. nov., a Novel Hyperthermophilic Starch-Degrading Archaeon.

A novel hyperthermophilic archaeon, termed strain T7324T, was isolated from a mixed sulfate-reducing consortium recovered from hot water produced from a deep North Sea oil reservoir. The isolate is a strict anaerobic chemo-organotroph able to utilize yeast extract or starch as a carbon source. The genes for a number of sugar degradation enzymes and glutamate dehydrogenase previously attributed to the sulfate reducing strain of the consortium (Archaeoglobus fulgidus strain 7324) were identified in the nearly completed genome sequence. Sequence analysis of the 16S rRNA gene placed the strain in the Thermococcus genus, but with an average nucleotide identity that is less than 90% to its closest relatives. Phylogenomic treeing reconstructions placed the strain on a distinct lineage clearly separated from other Thermococcus spp. The results indicate that the strain T7324T represents a novel species, for which the name Thermococcus bergensis sp. nov. is proposed. The type strain is T7324T (=DSM 27149T = KCTC 15808T).

Draft Genome Sequence of Bordetella sp. Strain FB-8, Isolated from a Former Uranium Mining Area in Germany.

Here, we present the draft genome sequence of Bordetella sp. strain FB-8, a mixotrophic iron-oxidizing bacterium isolated from creek sediment in the former uranium-mining district of Ronneburg, Germany. To date, iron oxidation has not been reported in Bordetella species, indicating that FB-8 may be an environmentally important Bordetella sp.

Draft genome sequence of Promicromonospora panici sp. nov., a novel ionizing-radiation-resistant actinobacterium isolated from roots of the desert plant Panicum turgidum.

A novel strain of the genus Promicromonospora, designated PT9T, was recovered from irradiated roots of the xerophyte Panicum turgidum collected from the Ksar Ghilane oasis in southern Tunisia. Strain PT9T is aerobic, non-spore-forming, Gram- positive actinomycete that produces branched hyphae and forms white to yellowish-white colonies. Chemotaxonomic features, including fatty acids, whole cell sugars and polar lipid profiles, support the assignment of PT9T to the genus Promicromonospora. The genomic relatedness indexes based on DNA-DNA hybridization and average nucleotide identity values revealed a significant genomic divergence between strain PT9T and all sequenced type strains of the taxon. Phylogenomic analysis showed that isolate PT9T was most closely related to Promicromonospora soli CGMCC 4.7398T. Phenotypic and phylogenomic analyses suggest that isolate PT9T represents a novel species of the genus Promicromonospora, for which the name Promicromonospora panici sp. nov. is proposed. The type strain is PT9T (LMG 31103T = DSM 108613T).The isolate PT9T is an ionizing-radiation-resistant actinobacterium (D10 value = 2.6 kGy), with resistance to desiccation and hydrogen peroxide. The complete genome sequence of PT9T consists of 6,582,650 bps with 71.2% G+C content and 6291 protein-coding sequences. This genome will help to decipher the microbial genetic bases for ionizing-radiation resistance mechanisms including the response to oxidative stress.

Comparative Genomic Study of Vinyl Chloride Cluster and Description of Novel Species, Mycolicibacterium vinylchloridicum sp. nov.

Advanced physicochemical and chemical absorption methods for chlorinated ethenes are feasible but incur high costs and leave traces of pollutants on the site. Biodegradation of such pollutants by anaerobic or aerobic bacteria is emerging as a potential alternative. Several mycobacteria including Mycolicibacterium aurum L1, Mycolicibacterium chubuense NBB4, Mycolicibacterium rhodesiae JS60, Mycolicibacterium rhodesiae NBB3 and Mycolicibacterium smegmatis JS623 have previously been described as assimilators of vinyl chloride (VC). In this study, we compared nucleotide sequence of VC cluster and performed a taxogenomic evaluation of these mycobacterial species. The results showed that the complete VC cluster was acquired by horizontal gene transfer and not intrinsic to the genus Mycobacterium sensu lato. These results also revealed the presence of an additional xcbF1 gene that seems to be involved in Coenzyme M biosynthesis, which is ultimately used in the VC degradation pathway. Furthermore, we suggest for the first time that S/N-Oxide reductase encoding gene was involved in the dissociation of the SsuABC transporters from the organosulfur, which play a crucial role in the Coenzyme M biosynthesis. Based on genomic data, M. aurum L1, M. chubuense NBB4, M. rhodesiae JS60, M. rhodesiae NBB3 and M. smegmatis JS623 were misclassified and form a novel species within the genus Mycobacterium sensu lato. Mycolicibacterium aurum L1T (CECT 8761T = DSM 6695T) was the subject of polyphasic taxonomic studies and showed ANI and dDDH values of 84.7 and 28.5% with its close phylogenetic neighbour, M. sphagni ATCC 33027T. Phenotypic, chemotaxonomic and genomic data considering strain L1T (CECT 8761T = DSM 6695T) as a type strain of novel species with the proposed name, Mycolicibacterium vinylchloridicum sp. nov.

Ionizing-radiation-resistant Kocuria rhizophila PT10 isolated from the Tunisian Sahara xerophyte Panicum turgidum: Polyphasic characterization and proteogenomic arsenal.

A new strain belonging to the genus Kocuria, designed PT10, was isolated from irradiated roots of the xerophyte Panicum turgidum. Isolate PT10 is a Gram-positive, coccoid, aerobic and ionizing-radiation (IR)-resistant actinobacterium. PT10 has shown an ability to survive under extreme conditions, such as gamma irradiation, desiccation and high concentration of hydrogen peroxide. Phenotypic, chemotaxonomic and comparative genome analyses support the assignment of strain PT10 (LMG 31102 = DSM 108617) as Kocuria rhizophila. The complete genome sequence of PT10 consists of one chromosome (2,656,287 bps), with a 70.7% G + C content and comprises 2481 protein-coding sequences. A total of 1487 proteins were identified by LC-MS/MS profiling. In silico analyses revealed that the proteome of the oxidation-tolerant PT10 possesses several features explaining its IR-resistant phenotype and many adaptive pathways implicated in response to environmental pressures - desiccation, cold, reactive oxygen species and other stressors.

Mixotrophic Iron-Oxidizing Thiomonas Isolates from an Acid Mine Drainage-Affected Creek.

Natural attenuation of heavy metals occurs via coupled microbial iron cycling and metal precipitation in creeks impacted by acid mine drainage (AMD). Here, we describe the isolation, characterization, and genomic sequencing of two iron-oxidizing bacteria (FeOB) species: Thiomonas ferrovorans FB-6 and Thiomonas metallidurans FB-Cd, isolated from slightly acidic (pH 6.3), Fe-rich, AMD-impacted creek sediments. These strains precipitated amorphous iron oxides, lepidocrocite, goethite, and magnetite or maghemite and grew at a pH optimum of 5.5. While Thiomonas spp. are known as mixotrophic sulfur oxidizers and As oxidizers, the FB strains oxidized Fe, which suggests they can efficiently remove Fe and other metals via coprecipitation. Previous evidence for Thiomonas sp. Fe oxidation is largely ambiguous, possibly because of difficulty demonstrating Fe oxidation in heterotrophic/mixotrophic organisms. Therefore, we also conducted a genomic analysis to identify genetic mechanisms of Fe oxidation, other metal transformations, and additional adaptations, comparing the two FB strain genomes with 12 other Thiomonas genomes. The FB strains fall within a relatively novel group of Thiomonas strains that includes another strain (b6) with solid evidence of Fe oxidation. Most Thiomonas isolates, including the FB strains, have the putative iron oxidation gene cyc2, but only the two FB strains possess the putative Fe oxidase genes mtoAB The two FB strain genomes contain the highest numbers of strain-specific gene clusters, greatly increasing the known Thiomonas genetic potential. Our results revealed that the FB strains are two distinct novel species of Thiomonas with the genetic potential for bioremediation of AMD via iron oxidation.IMPORTANCE As AMD moves through the environment, it impacts aquatic ecosystems, but at the same time, these ecosystems can naturally attenuate contaminated waters via acid neutralization and catalyzing metal precipitation. This is the case in the former Ronneburg uranium-mining district, where AMD impacts creek sediments. We isolated and characterized two iron-oxidizing Thiomonas species that are mildly acidophilic to neutrophilic and that have two genetic pathways for iron oxidation. These Thiomonas species are well positioned to naturally attenuate AMD as it discharges across the landscape.

Genomic Virulence Features of Two Novel Species Nocardia barduliensis sp. nov. and Nocardia gipuzkoensis sp. nov., Isolated from Patients with Chronic Pulmonary Diseases.

Strains 335427T and 234509T, isolated from two 76-year-old patients with chronic pulmonary diseases, were the subject of polyphasic taxonomic studies and comparative genomic analyses for virulence factors. The 16 rRNA gene sequence similarity between strains 335427T and 234509T and their closest phylogenetic neighbors Nocardia asiatica NBRC 100129T and Nocardia abscessus NBRC 100374T were 99.5% and 100%, respectively. Digital DNA-DNA hybridization values between the aforementioned studied strains were well below the 70% threshold for assigning prokaryotic strains to a novel species. Strains 335427T and 234509T have genome sizes of 8.49 Mpb and 8.07 Mpb, respectively, with G + C content of 68.5%. Isolate 335427T has C16:0, C18:1 ω9c, C18:0 and C18:0 10 methyl as major fatty acids (>15%) and mycolic acids formed of 52-54 carbon atoms. However, only C18:1 ω9c was detected for isolate 234509T, which had mycolic acids with 44-56 carbon. Based on phenotypic and genetic data, strains 335427T (DSM 109819T = CECT 9924T) and 234509T (DSM 111366T = CECT 30129T) merit recognition as novel species, which are named Nocardia barduliensis sp. nov. and Nocardia gipuzkoensis sp. nov., respectively. All the strains studied had homologous VF-associated genes to those described in M. tuberculosis, including experimentally verified virulence genes in humans related to tuberculosis. The narGHIJ (nitrate reduction pathway) and gvpAFGOJLMK (gas vesicles) genetic maps of strains 335427T, 234509T, NBRC 100129T and NBRC 100374T showed the same syntenic block and raise the question of whether their functions are interlinked during the infection of the human host. However, further research is required to decipher the role of the gas vesicle in the pathogenicity mechanism of Nocardia spp.

Streptomyces harenosi sp. nov., a home for a gifted strain isolated from Indonesian sand dune soil.

A polyphasic study was undertaken to establish the position of a Streptomyces strain, isolate PRKS01-65T, recovered from sand dune soil collected at Parangkusumo, Yogyakarta Province, Java, Indonesia. A combination of chemotaxonomic, cultural and morphological properties confirmed its position in the genus of Streptomyces. Comparative 16S rRNA gene sequence analyses showed that the isolate was most closely related to Streptomyces leeuwenhoekii C34T (99.9 % similarity) and loosely associated with the type strains of Streptomyces chiangmaiensis (98.7 % similarity) and Streptomyces glomeratus (98.9 % similarity). Multilocus sequence analyses based on five conserved housekeeping gene alleles confirmed the close relationship between the isolate and S. leeuwenhoekii C34T, although both strains belonged to a well-supported clade that encompassed the type strains of S. glomeratus, Streptomyces griseomycini, Streptomyces griseostramineus, Streptomyces labedae, Streptomyces lomondensis and Streptomyces spinoverrucosus. A comparison of the draft genome sequence generated for the isolate with corresponding whole genome sequences of its closest phylogenomic neighbours showed that it formed a well-separated lineage with S. leeuwenhoekii C34T. These strains can also be distinguished using a combination of phenotypic properties and by average nucleotide identity and digital DNA-DNA hybridization similarities of 94.3 and 56 %, values consistent with their classification in different species. Based on this wealth of data it is proposed that isolate PRKS01-65T (=NCIMB 15211T=CCMM B1302T=ICEBB-03T) be classified as Streptomyces harenosi sp. nov. The genome of the isolate contains several biosynthetic gene clusters with the potential to produce new natural products.