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Two novel actinobacteria, designated as SYSU M7M538 T and SYSU M7M531, were isolated from oral of Eumetopias jubatus in Zhuhai Chimelong Ocean Kingdom, China. The cells of these microorganisms stained Gram-positive and were rod shaped. These strains were facultative anaerobic, and catalase-positive. Optimal growth occurred at 37 °C and pH 7.0 over 7 days of cultivation. Both strains possessed diphosphatidylglycerol, phosphatidylglycerol and phosphocholine as the major polar lipids. The main menaquinone was MK-9(H 4 ). The major fatty acids were C 16:0 , C 17:1 w 8 c , C 17:0 , C 18:1 w 9 c and C 18:0 . Analyses of genome sequences revealed that the genome size of SYSU M7M538 T was 2.1 Mbp with G + C content of 52.5 %, while the genome size of SYSU M7M531 was 2.3 Mbp with G + C content of 52.7 %. The ANI and 16S rRNA gene analysis results showed that the pairwise similarities between the two strains and other recognized Nitriliruptoria species were less than 64.9 % and 89.0 %, respectively. Phylogenetic analysis of the 16S rRNA gene sequences indicated that strains SYSU M7M538 T and SYSU M7M531 formed a well-separated phylogenetic branch distinct from other orders of Nitriliruptoria. Based on the data presented here, these two strains are considered to represent a novel species of a novel genus, for which the name Stomatohabitans albus gen. nov., sp. nov., with the type strain SYSU M7M538 T (=KCTC 59113 T  = GDMCC 1.4286 T ), are proposed. We also propose that these organisms represent a novel family named Stomatohabitantaceae fam. nov. of a novel order Stomatohabitantales ord. nov., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

In this study, we employed a polyphasic approach to determine the taxonomic position of a newly isolated actinomycete, designated SE31 T , obtained from a sediment sample collected at Cape Rochado, Malaysia. Phylogenetic analysis of the 16S rRNA gene sequence revealed that strain SE31 T belonged to the family Pseudonocardiaceae and exhibited the highest sequence similarity (98.9%) to Sciscionella marina. Further genomic analysis demonstrated a 93.4% average nucleotide identity and 54.4% digital DNA-DNA hybridization relatedness between strain SE31 T and S. marina. The chemotaxonomic characteristics of strain SE31 T were typical of the genus Sciscionella, including cell-wall chemotype IV (with meso-diaminopimelic acid as the diagnostic diamino acid, and arabinose and galactose as whole-cell sugars). The identified polar lipids of strain SE31 T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylmethylethanolamine, and hydroxyphosphatidymethylethanolamine. The primary menaquinone observed was MK-9(H 4 ), and the major cellular fatty acid was iso-C 16:0 . The genomic DNA size of strain SE31 T was determined to be 7.4 Mbp with a G+C content of 68.7%. Based on these comprehensive findings, strain SE31 T represents a novel species within the genus Sciscionella, in which the name Sciscionella sediminilitoris sp. nov. is proposed. The type strain of Sciscionella sediminilitoris is SE31 T (= DSM 46824 T  = TBRC 5134 T )., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

A novel actinomycete, designated strain q2 T , was isolated from the saline-alkaline soil, collected from Daqing, Heilongjiang province, China. The results of phylogenetic analysis based on the 16S rRNA gene sequences indicated that strain q2 T belongs to the genus Isoptericola, and showed the highest sequence similarity to Isoptericola halotolerans KCTC 19046 T (98.48%) and Isoptericola chiayiensis KCTC 19740 T (98.13%), respectively. The average nucleotide identity values between strain q2 T and other members of the genus Isoptericola were lower than 95% recommended for distinguishing novel prokaryotic species. Cells of strain q2 T were Gram-staining-positive, aerobic, non-motile, rod-shaped and non-spore-forming. Colonies of strain q2 T were golden-yellow pigmented, tidy edged and smooth surfaced. Growth occurred at 15-37 °C (optimum, 29 °C), pH 7.0-10.0 (optimum, pH 8.0). The predominant respiratory quinones were MK-9(H 4 ) and MK-9(H 2 ). The main detected polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, and phosphatidylinositol mannoside. The peptidoglycan compositions were L-alanine, D-aspartic, L-glutamic acid and L-lysine (type A4α). The major cellular fatty acids (> 10%) were anteiso-C 15:0 , iso-C 15:0 , and anteiso-C 17:0 . The G+C content of the genomic DNA was determined to be 69.7%. Based on the phenotypic, physiological, genotypic, and phylogenetic data, strain q2 T represents a novel species of the genus Isoptericola, for which the name Isoptericola croceus sp. nov. is proposed. The type strain is q2 T (= GDMCC 1.2923 T  = KCTC 49759 T )., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Two new α -pyrones, micropyrones A ( 1 ) and B ( 2 ), along with four known γ -pyrones, nocapyrone D ( 3 ), nocapyrone A ( 4 ), marinactinone A ( 5 ), and nocapyrone H ( 6 ), were isolated from the culture extract of actinomycete Microbacterium sp. GJ312, which was isolated from Glycyrrhiza uralensis . The structures of these compounds were identified by analysis of spectral data. They are the first α - and γ -pyrones reported from the genus Microbacterium . The antibacterial activity of all compounds against Staphylococcus aureus and methicillin resistant S. aureus was evaluated. However, none of them showed significant activity. This study represents the first phytochemical example of a Glycyrrhiza -derived actinomycete.

An actinobacterium, designated strain EGI L10124 T , was isolated from saline lake sediment collected in Xinjiang province, PR China. The taxonomic position of the isolate was determined based on polyphasic taxonomic and phylogenomic analyses. Phylogenetic analysis and 16S rRNA gene sequence similarities indicated that strain EGI L10124 T formed a distinct clade with Rhabdothermincola sediminis SYSU G02662 T , with a shared sequence identity of 95.2 %. The novel isolate could be distinguished from species in the genus Rhabdothermincola by its distinct phenotypic, physiological and genotypic characteristics. The cells of strain EGI L10124 T were aerobic, Gram-stain-positive and short rod-shaped. Optimal growth conditions of strain EGI L10124 T on marine agar 2216 were registered at pH 8.0 at 37 °C. In addition, meso -diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. The major respiratory quinone was MK-9 (H 8 ), while the major fatty acids were iso-C 16 : 0 , C 17 : 0 and C 16 : 0 . The polar lipids included diphosphatidylglycerol, phosphatidylinositol mannoside and phosphatidylinositol. Based on the genome sequence of strain EGI L10124 T , it appears that the G+C content of the novel isolate was 71.8 mol%. According to our data, strain EGI L10124 T represents a new species of the genus Rhabdothermincola , for which the name Rhabdothermincola salaria sp. nov. is proposed. The type strain of the proposed novel isolate is EGI L10124 T (=CGMCC 1.19113 T =KCTC 49679 T ).

A bacterial strain, designated YZGR15 T , was isolated from the root of an annual halophyte Suaeda aralocaspica , collected from the southern edge of the Gurbantunggut desert, north-west PR China. Cells of the isolate were Gram-stain-positive, facultatively anaerobic, irregular rods. Growth occurred at 4-42 °C (optimum, 30-37 °C), at pH 6.0-9.0 (optimum, pH 7.0-7.5) and in the presence of 0-9 % (w/v) NaCl (optimum, 2-5 %). Phylogenetic analysis using 16S rRNA gene sequences indicated that strain YZGR15 T showed the highest sequence similarity to Sanguibacter keddieii (98.27 %) , Sanguibacter antarcticus (98.20 %) and Sanguibacter inulinus (98.06 %). Results of genome analyses of strain YZGR15 T indicated that the genome size was 3.16 Mb, with a genomic DNA G+C content of 71.9 mol%. Average nucleotide identity and digital DNA-DNA hybridization values between strain YZGR15 T and three type strains were in the range of 76.5-77.8 % and 20.0-22.2 %, respectively. Analysis of the cellular component of strain YZGR15 T revealed that the primary fatty acids were anteiso-C 15 : 0 , C 16 : 0 , C 14 : 0 and iso-C 16 : 0 and the polar lipids included diphosphatidylglycerol, phosphatidylglycerol, three unidentified phospholipids and two unidentified glycolipids. The cell-wall characteristic amino acids were glutamic acid, alanine and an unknown amino acid. The whole-cell sugars for the strain were mannose, ribose, rhamnose, glucose and an unidentified sugar. The predominant respiratory quinone was MK-9(H 4 ). Based on the results of genomic, phylogenetic, phenotypic and chemotaxonomic analyses, strain YZGR15 T represents a novel species of the genus Sanguibacter , for which the name Sanguibacter suaedae sp. nov. is proposed. The type strain is YZGR15 T (=CGMCC 1.18691 T =KCTC 49659 T ).

The haloalkalitolerant bacterium Egicoccus halophilus EGI 80432 T exhibits high adaptability to saline-alkaline environment. The salinity adaptation mechanism of E. halophilus EGI 80432 T was fully understood based on transcriptome analyses and physiological responses; however, the alkaline response mechanism has not yet been investigated. Here, we investigated the alkaline response mechanism of E. halophilus EGI 80432 T by a transcriptomic comparison. In this study, the genes involved in the glycolysis, TCA cycle, starch, and trehalose metabolism for energy production and storage, were up-regulated under highly alkaline condition. Furthermore, genes responsible for the production of acidic and neutral metabolites, i.e., acetate, pyruvate, formate, glutamate, threonine, and ectoine, showed increased expression under highly alkaline condition, compared with the control pH condition. In contrast, the opposite results were observed in proton capture or retention gene expression profiles, i.e., cation/proton antiporters and ATP synthases. The above results revealed that E. halophilus EGI 80432 T likely tended to adopt an "acidic metabolites production" strategy in response to a highly alkaline condition. These findings would pave the way for further studies in the saline-alkaline adaptation mechanisms of E. halophilus EGI 80432 T , and hopefully provide a new insight into the foundational theory and application in ecological restoration with saline-alkaline strains., (© 2021. The Author(s), under exclusive licence to Springer Japan KK, part of Springer Nature.)

Streptomycetes have been, for over 70 years, one of the most abundant sources for the discovery of new antibiotics and clinic drugs. However, in recent decades, it has been more and more difficult to obtain new phylotypes of the genus Streptomyces by using conventional samples and culture strategies. In this study, we combined culture-dependent and culture-independent approaches to better explore the Streptomyces communities in desert sandy soils. Moreover, two different culture strategies termed Conventional Culture Procedure (CCP) and Streptomycetes Culture Procedure (SCP) were employed to evaluate the isolation efficiency of Streptomyces spp. with different intensities of selectivity. The 16S rRNA gene amplicon analysis revealed a very low abundance (0.04-0.37%, average 0.22%) of Streptomyces in all the desert samples, conversely the percentage of Streptomyces spp. obtained by the culture-dependent method was very high (5.20-39.57%, average 27.76%), especially in the rhizospheric sand soils (38.40-39.57%, average 38.99%). Meanwhile, a total of 1589 pure cultures were isolated successfully, dominated by Streptomyces (29.52%), Microvirga (8.06%) and Bacillus (7.68%). In addition, 400 potential new species were obtained, 48 of which belonged to the genus Streptomyces. More importantly, our study demonstrated the SCP strategy which had highly selectivity could greatly expand the number and phylotypes of Streptomyces spp. by almost 4-fold than CCP strategy. These results provide insights on the diversity investigation of desert Streptomyces, and it could be reference for researchers to bring more novel actinobacteria strains from the environment into culture., Competing Interests: Declaration of competing interest All co-authors have seen and agree with the contents of the manuscript. We declare that we have no known competing financial and personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Carbon fixation by chemoautotrophic microbes such as homoacetogens had a major impact on the transition from the inorganic to the organic world. Recent reports have shown the presence of genes for key enzymes associated with the Wood-Ljungdahl pathway (WLP) in the phylum Actinobacteria, which adds to the diversity of potential autotrophs. Here, we compiled 42 actinobacterial metagenome-assembled genomes (MAGs) from new and existing metagenomic datasets and propose three novel classes, Ca. Aquicultoria, Ca. Geothermincolia and Ca. Humimicrobiia. Most members of these classes contain genes coding for acetogenesis through the WLP, as well as a variety of hydrogenases (NiFe groups 1a and 3b-3d; FeFe group C; NiFe group 4-related hydrogenases). We show that the three classes acquired the hydrogenases independently, yet the carbon monoxide dehydrogenase/acetyl-CoA synthase complex (CODH/ACS) was apparently present in their last common ancestor and was inherited vertically. Furthermore, the Actinobacteria likely donated genes for CODH/ACS to multiple lineages within Nitrospirae, Deltaproteobacteria (Desulfobacterota), and Thermodesulfobacteria through multiple horizontal gene transfer events. Finally, we show the apparent growth of Ca. Geothermincolia and H 2 -dependent acetate production in hot spring enrichment cultures with or without the methanogenesis inhibitor 2-bromoethanesulfonate, which is consistent with the proposed homoacetogenic metabolism., (© 2021. The Author(s), under exclusive licence to International Society for Microbial Ecology.)

A novel actinobacterium, designated strain SYSU M44304 T , was isolated from freshwater samples in the Pearl River Estuary. The isolate was Gram-stain-positive, aerobic, coccus-shaped, oxidase-positive and motile. The cell wall contained meso -diaminopimelic acid as its diagnostic diamino acid. The predominant menaquinone was MK-8. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine and seven unidentified phospholipids. The major fatty acids were C 16 : 0 and C 16 : 1 . The G+C content based on genomic DNA was 73.2 mol %. The nearest phylogenetic neighbours to the novel strain were Mobilicoccus pelagius NBRC 104925 T and Mobilicoccus caccae YIM 101593 T . On the basis of chemotaxonomic and physiological characteristics and phylogenetic analysis, strain SYSU M44304 T should be considered to represent a novel species of a new genus in the family Dermatophilaceae , for which we propose the name Agilicoccus flavus gen. nov., sp. nov. The type strain of Agilicoccus flavus is SYSU M44304 T (=NBRC 114808 T =CGMCC 1.18608 T ).

The taxonomic positions of members within the family Pseudonocardiaceae were assessed based on phylogenomic trees reconstructed using core-proteome and genome blast distance phylogeny approaches. The closely clustered genome sequences from the type strains of validly published names within the family Pseudonocardiaceae were analysed using overall genome-related indices based on average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization values. The family Pseudonocardiaceae consists of the type genus Pseudonocardia , as well as the genera Actinoalloteichus , Actinocrispum , Actinokineospora , Actinomycetospora , Actinophytocola , Actinopolyspora , Actinorectispora , Actinosynnema , Allokutzneria , Allosaccharopolyspora gen. nov., Amycolatopsis , Bounagaea , Crossiella , Gandjariella , Goodfellowiella , Haloactinomyces , Haloechinothrix , Halopolyspora , Halosaccharopolyspora gen. nov., Herbihabitans , Kibdelosporangium , Kutzneria , Labedaea , Lentzea , Longimycelium , Prauserella , Saccharomonospora , Saccharopolyspora , Saccharothrix , Salinifilum , Sciscionella , Streptoalloteichus , Tamaricihabitans , Thermocrispum , Thermotunica and Umezawaea . The G+C contents of the Pseudonocardiaceae genomes ranged from 66.2 to 74.6 mol% and genome sizes ranged from 3.69 to 12.28 Mbp. Based on the results of phylogenomic analysis, the names Allosaccharopolyspora coralli comb. nov., Halosaccharopolyspora lacisalsi comb. nov. and Actinoalloteichus caeruleus comb. nov. are proposed. This study revealed that Actinokineospora mzabensis is a heterotypic synonym of Actinokineospora spheciospongiae , Lentzea deserti is a heterotypic synonym of Lentzea atacamensis , Prauserella endophytica is a heterotypic synonym of Prauserella coralliicola , and Prauserella flava and Prauserella sediminis are heterotypic synonyms of Prauserella salsuginis . This study addresses the nomenclature conundrums of Actinoalloteichus cyanogriseus and Streptomyces caeruleus as well as Micropolyspora internatus and Saccharomonospora viridis .

The removal of toxic heavy metal ions from contaminated environments is a great challenge and requires an alternative rapid, efficient, economical bioremediation approach. Henceforth, bioflocculant producing endophytic actinobacterial sp. was isolated from heavy metal contaminated marine environments for heavy metal biosorption process. After molecular characterization, the isolated actinomycete starin was Nocardiopsis sp. GRG 3 (KT235642). It was indicated that the maximum flocculating activity of 80.90% with glucose, and yield is 4.52 g L 1 . The optimum flocculating activity was reached at pH 7 in the presence of CaCl 2 ions. Further, the bioflocculent produced Nocardiopsis sp. GRG 3 (KT235642) was characterized by fourier transform infrared analysis spectra (FTIR) and displayed the presence of carboxyl, hydroxyl, amino groups and characteristic of more polysaccharide and protein. The heavy metal sorption by bioflocculant Nocardiopsis sp. GRG 3 (KT235642) was effectively removed 55.90% Cd, 85.90% Cr, 74.7% Pb, and 51.90% Hg. Therefore, this study was proved that the bioflocculant derived from endophytic actinobacteria, Nocardiopsis sp. GRG 3 (KT235642) as a effective alternative method for decreasing the heavy metals towards sustainable environmental management., (Copyright © 2021 Elsevier Inc. All rights reserved.)

A novel Gram-stain-positive, catalase-positive, oxidase-negative, aerobic, non-motile, rod-shaped bacterium, designated strain YIM M12148 T , was isolated from a marine sediment sample collected from the Indian Ocean. The strain grew optimally at 28 °C, pH 8.0 and in the presence of 1-3 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM M12148 T belongs to the genus Gulosibacter , with the highest sequence similarity to Gulosibacter faecalis NBRC 15706 T (96.12 %). The cell-wall sugars of strain YIM M12148 T were rhamnose, ribose, glucose and mannose. The predominant isoprenoid quinones were MK-8 and MK-9. The polar lipids consisted of major amounts of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unknown phospholipid and one unknown lipid. Major fatty acids (>5 % of the total) of the novel isolate were anteiso-C 15 : 0 , iso-C 15 : 0 , iso-C 13 : 0 and anteiso-C 13 : 0 . The genomic DNA G+C content of strain YIM M12148 T was 67.15 mol%. On the basis of genotypic and phenotypic data, it is apparent that strain YIM M12148 T represents a novel species of the genus Gulosibacter , for which the name Gulosibacter sediminis sp. nov. is proposed. The type strain is YIM M12148 T (=KCTC 29660 T =DSM 29154 T ).

Egicoccus halophilus EGI 80432 T , a halotolerant bacterium isolated from a saline-alkaline soil, belongs to a member of the class Nitriliruptoria, which exhibits high adaptability to salt environments. At present, the detailed knowledge of the salinity adaptation strategies of Nitriliruptoria was limited except for one research by using comparative genomics analysis. Here, we investigated the salinity adaptation mechanism of E. halophilus EGI 80432 T by comparative physiological and transcriptomic analyses. The results of physiological analyses showed that trehalose and glutamate were accumulated by salt stress and showed the maximum at moderate salinity condition. Furthermore, the contents of histidine, threonine, proline, and ectoine were increased with increasing salt concentration. We found that both 0% and 9% NaCl conditions resulted in increased expressions of genes involved in carbohydrate and energy metabolisms, but negatively affected the Na + efflux, iron, and molybdate transport. Moreover, the high salt condition led to enhancement of transcription of genes required for the synthesis of compatible solutes, e.g., glutamate, histidine, threonine, proline, and ectoine, which agree with the results of physiological analyses. The above results revealed that E. halophilus EGI 80432 T increased inorganic ions uptake and accumulated trehalose and glutamate in response to moderate salinity condition, while the salinity adaptation strategy was changed from a "salt-in-cytoplasm" strategy to a "compatible solute" strategy under high salinity condition. The findings in this study would promote further studies in salt tolerance molecular mechanism of Nitriliruptoria and provide a theoretical support for E. halophilus EGI 80432 T 's application in ecological restoration.Key Points• Salt stress affected gene expressions responsible for carbohydrate and energy metabolisms of E. halophilus EGI 8042 T .• E. halophilus EGI 80432 T significantly accumulated compatible solutes under salt stress.• E. halophilus EGI 80432 T adopted a "compatible solute" strategy to withstand high salt stress.

Strain DRQ-2 T (type strain of Nonomuraea indica) is worthy for genome sequencing, due to its ability to produce a wide variety of industrially important enzymes such as amylase, asparaginase, cellulase, gelatinase, glutaminase, and protease. Genome sequencing and comparison of strain DRQ-2 T is described in the present work. The genome size was estimated to be 8,288,417 (bp) that consisted of 59 contigs. The G + C content of the genome was 72.4%. A total of 7730 genes were predicted with two rRNAs and 64 tRNAs. The genome analysis of the strain DRQ-2 T showed the presence of a wide range of secondary metabolite gene clusters. Pan-Genomes Analysis Pipeline (PGAP) indicated that strain DRQ-2 T had large numbers of unique genes. The majority of N. indica DRQ-2 T genes encode for hypothetical proteins, indicating the functions of these ortholog clusters were still remain to be determined., Competing Interests: Declaration of Competing Interest The authors declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work. There is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in the manuscript entitled, “Genome sequence and comparative analysis of DRQ-2, the type strain of Nonomuraea indica”., (Copyright © 2020. Published by Elsevier Inc.)

The taxonomic status of a Nocardiopsis strain, designated H13 T , isolated from a high altitude Atacama Desert soil, was established by using a polyphasic approach. The strain was found to have chemotaxonomic, cultural and morphological characteristics consistent with its classification within the genus Nocardiopsis and formed a well-supported clade in the Nocardiopsis phylogenomic tree together with the type strains of Nocardiopsis alborubida , Nocardiopsis dassonvillei and Nocardiopsis synnematoformans . Strain H13 T was distinguished from its closest relatives by low average nucleotide identity (93.2-94.9 %) and in silico DNA-DNA hybridization (52.5-62.4 %) values calculated from draft genome assemblies and by a range of phenotypic properties. On the basis of these results, it is proposed that the isolate be assigned to the genus Nocardiopsis as Nocardiopsis deserti sp. nov. with isolate H13 T (=CGMCC 4.7585 T =KCTC 49249 T ) as the type strain.

A novel endophytic actinobacterium, designated strain EGI 650086 T , was isolated from the roots of Anabasis elatior (C.A.Mey.) Schischk. collected in Xinjiang, north-west China. The taxonomic position of the strain was investigated using a polyphasic taxonomic approach. Growth occurred at 15-40 °C, pH 6.0-8.0 and in the presence of 0-6 % NaCl (w/v). Phylogenetic analysis based on 16S rRNA gene sequence and concatenation of 22 protein marker genes revealed that strain EGI 650086 T formed a monophyletic clade within the genus Amycolatopsis and shared the highest sequence similarities with Amycolatopsis nigrescens JCM 14717 T (97.1 %) and Amycolatopsis sacchari DSM 44468 T (97.0 %). Sequence similarities with type strains of other species of the genus Amycolatopsis were less than 97.0 %. The average nucleotide identity and DNA-DNA hybridization values between strain EGI 650086 T and the reference strains were 78.1-79.8 % and 22.1-23.0 %, respectively. The genome of strain EGI 650086 T was 10.9 Mb, with a DNA G+C content of 70.1 mol%. The diagnostic diamino acid in the peptidoglycan was meso -diaminopimelic acid. The major whole-cell sugars contained arabinose, galactose, glucose and ribose. The predominant menaquinones were MK-9 (H 4 ) and MK-9 (H 2 ). Major fatty acids were iso -C 16 : 0 and summed feature 4 ( iso -C 17 : 1 I and/or anteiso -C 17 : 1 B). The polar lipid profile of strain EGI 650086 T included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, hydroxy-phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides, two unknown phospholipids, an unknown glycolipid and an unknown lipid. Polyphasic taxonomic characteristics indicated that strain EGI 650086 T represents a novel species of the genus Amycolatopsis , for which the name Amycolatopsis anabasis sp. nov. is proposed. The type strain is EGI 650086 T (=KCTC 49044 T =CGMCC 4.7188 T ).

Endophytic microbes associated with medicinal plants are considered to be potential producers of various bioactive secondary metabolites. The present study investigated the distribution, antimicrobial activity and genetic features of endophytic actinomycetes isolated from the medicinal plant Cinnamomum cassia Presl collected in Hoa Binh province of northern Vietnam. Based on phenotypic characteristics, 111 actinomycetes were isolated from roots, stems and leaves of the host plants by using nine selective media. The isolated actinomycetes were mainly recovered from stems (n = 67; 60.4%), followed by roots (n = 29; 26.1%) and leaves (n = 15; 13.5%). The isolates were accordingly assigned into 5 color categories of aerial mycelium, of which gray is the most dominant (n = 42; 37.8%), followed by white (n = 33; 29.7%), yellow (n = 25; 22,5%), red (n = 8; 7.2%) and green (n = 3; 2.7%). Of the total endophytic actinomycetes tested, 38 strains (occupying 34.2%) showed antimicrobial activity against at least one of nine tested microbes and, among them, 26 actinomycetes (68.4%) revealed anthracycline-like antibiotics production. Analysis of 16S rRNA gene sequences deposited on GenBank (NCBI) of the antibiotic-producing actinomycetes identified 3 distinct genera, including Streptomyces, Microbacterium, and Nocardia, among which Streptomyces genus was the most dominant and represented 25 different species. Further genetic investigation of the antibiotic-producing actinomycetes found that 28 (73.7%) and 11 (28.9%) strains possessed genes encoding polyketide synthase (pks) and nonribosomal peptide synthetase (nrps), respectively. The findings in the present study highlighted endophytic actinomycetes from C. cassia Presl which possessed broad-spectrum bioactivities with the potential for applications in the agricultural and pharmaceutical sectors.

A Gram-staining-positive, aerobic, non-motile, non-spore-forming and coccoid-shaped actinobacterial strain, designated YIM 730233 T , was isolated from a sediment sample, collected from a hot spring in Tibet, China. Colonies were brownish, circular, smooth and convex. Strain YIM 730233 T was able to grow in the temperature range of 20-50 °C, pH 6.5-8.0 and in the presence of up to 1.0 % (w/v) NaCl. A comparison of the 16S rRNA gene sequence of strain YIM 730233 T with sequences of type strains of most closely related species of Marmoricola showed highest sequence similarities to Marmoricola bigeumensis MSL-05 T (98.3%) and Marmoricola pocheonensis Gsoil 818 T (98.1%). The draft genome of strain YIM 730233 T had a size of 4 806 234 bp with a DNA G+C content of 72.1 mol%. The major fatty acids (>10 %) of strain YIM 730233 T mainly consisted of iso-C 16 : 0 , anteiso-C 17 : 0 and C 18 : 1 ω 9c , typical of the genus Marmoricola . Strain YIM 730233 T had LL-2,6-diaminopimelic acid as the diagnostic diamino acid in the cell wall. The predominant isoprenoid quinone was MK-8(H 4 ). The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, unidentified phospholipids and an unidentified lipid. DNA-DNA hybridizations between strain YIM 730233 T and type strains of Marmoricola bigeumensis MSL-05 T and Marmoricola pocheonensis Gsoil 818 T resulted in similarity values of 21 and 19% respectively. Based on DNA-DNA hybridization results, together with the differentiating biochemical and chemotaxonomic features, showed that strain YIM 730233 T represents a novel Marmoricola species, for which the name Marmoricola caldifontis sp. nov. (type strain YIM 730233 T =KCTC 49192 T =CGMCC 4.7521 T ), is proposed.

Genome analysis is one of the main criteria for description of new taxa. Availability of genome sequences for all the actinobacteria with a valid nomenclature will, however, require another decade's works of sequencing. This paper describes the rearrangement of the higher taxonomic ranks of the members of the phylum ' Actinobacteria ', using the phylogeny of 16S rRNA gene sequences and supported by the phylogeny of the available genome sequences. Based on the refined phylogeny of the 16S rRNA gene sequences, we could arrange all the members of the 425 genera of the phylum ' Actinobacteria ' with validly published names currently in use into six classes, 46 orders and 79 families, including 16 new orders and 10 new families. The order Micrococcales Prévot 1940 (Approved Lists 1980) emend. Nouioui et al . 2018 is now split into 11 monophyletic orders: the emended order Micrococcales and ten proposed new orders Aquipuribacterales , Beutenbergiales , Bogoriellales , Brevibacteriales , Cellulomonadales , Demequinales , Dermabacterales , Dermatophilales , Microbacteriales and Ruaniales . Further, the class ' Actinobacteria ' Stackebrandt et al . 1997 emend. Nouioui et al . 2018 was described without any nomenclature type, and therefore the name ' Actinobacteria ' is deemed illegitimate. In accordance to Rule 8 of the International Code of Nomenclature of Prokaryotes, Parker et al . 2019, we proposed the name Actinomycetia which is formed by using the stem of the name Actinomycetales Buchanan 1917 (Approved Lists 1980) emend. Zhi et al . 2009, to replace the name ' Actinobacteria '. The nomenclature type of the proposed new class Actinomycetia is the order Actinomycetales Buchanan 1917 (Approved Lists 1980) emend. Zhi et al . 2009.

A genome-based phylogeny of the publicly available genomes of the genus Nocardiopsis reveals that Nocardiopsis baichengensis YIM 90130 T is closely related to Nocardiopsis halophila DSM 44494 T . Overall genome relatedness indices between the genomes of the two species were above the threshold values necessary for defining a new species (dDDH, 82.9 %; ANIb, 97.8 %; ANIm, 98.3 %; AAI, 97.7 %). Both species showed a similar G+C content of 73.6 mol% in their genomes. Considering the high similarity between the genomes of the two species, we propose that Nocardiopsisbaichengesis Li et al . 2006 should be reclassified as a later heterotypic synonym of Nocardiopsis halophila Al-Tai and Ruan 1994.

A novel actinobacterium, designated strain CFH 30434 T , was isolated from a soil sample collected from a karst cave in Luoyang, Henan Province, PR China. The taxonomic position of the strain was investigated by using a polyphasic approach. Cells of the strain were aerobic, Gram-stain-positive, non-motile and coccoid or short rods. The strain was found to be oxidase-positive and weakly catalase-positive. Strain CFH 30434 T grew optimally at 28 °C, pH 7.0-9.0 and in the presence of up to 0-1.5 % NaCl (w/v). The whole-cell sugars were glucose, mannose and rhamnose. The major isoprenoid quinone was MK-9(H 8 ) and the major fatty acids (>10 % of the total fatty acids compositions) were anteiso-C 15 : 0 , iso-C 15:0 and iso-C 14 : 0 . The polar lipids detected were diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, an unidentified phosphoglycolipid, an unidentified phospholipid and an unidentified glycolipid. The genomic DNA G+C content was determined to be 72.3 mol%. The results of phylogenetic analysis of 16S rRNA gene sequences indicated that CFH 30434 T clustered within the family Promicromonosporaceae , and closely with the type strains of Xylanimicrobium pachnodae DSM 12657 T , Myceligenerans crystallogenes DSM 17134 T and Promicromonospora xylanilytica CCTCC AA 208046 T (97.3 %, 96.2 and 95.9 % sequence similarities, respectively). Phylogenetic analysis showed that strain CFH 30434 T formed a separate evolutionary branch, and was parallel to other related genera of Promicromonosporaceae . Its phylogenetic distinctiveness and distinguishing phenotypic characteristics supported that strain CFH 30434 T represents a novel genus of the family Promicromonosporaceae , for which the name Antribacter gilvus gen. nov., sp. nov. is proposed. The type strain is CFH 30434 T (=CGMCC 1.13856 T =KCTC 49093 T ).

Background: Bursaphelenchus xylophilus is a migratory endoparasitic nematode known to cause severe environmental damage and economic losses in pine forest ecosystems. This present study investigated the nematicidal metabolites of actinomycetes in vitro and evaluated the disease control efficacy of the active compound and metabolites under greenhouse and field conditions., Results: Five thousand types of actinobacteria from Korean forest soil samples were screened to identify novel nematicidal agents against the pine wood nematode. Streptomyces sp. AN091965 showed the strongest nematicidal activity. One active compound, spectinabilin, was obtained by nematicidal asssy-directed fractionation, and it showed significant nematicidal activity against B. xylophilus, with an LC 50 value of 0.84 µg mL -1 . Spectinabilin effectively suppressed the development of pine wilt disease in 5-year-old Pinus densiflora trees, even at 0.9 mg per tree under greenhouse conditions. Moreover, the acetone extract of the active strain's mycelia efficiently suppressed the development of pine wilt disease under field conditions., Conclusion: To the best of our knowledge, this the first report to describe the nematicidal activity of spectinabilin against B. xylophilus. The cell extracts described herein merit further field studies as potential nematicides against the pine wood nematode. © 2018 Society of Chemical Industry., (© 2018 Society of Chemical Industry.)

A novel endophytic bacterium, designated strain SZ4R5S7 T , was isolated from surface-sterilized root of an endangered medicinal plant (Ferula songorica Pall. ex Spreng) collected from Xinjiang, north-west China. The taxonomic position of the strain was investigated by using a polyphasic approach. The strain was found to be aerobic, Gram-stain-positive, oxidase-negative and catalase-positive, short rods and non-motile. Strain SZ4R5S7 T grew at 4-37 °C (optimum, 28 °C), pH 5.0-9.0 (pH 6.0-8.0) and in the presence of 0-4 % (w/v) NaCl. The polar lipids detected for strain SZ4R5S7 T were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol and two unidentified lipids. The predominant menaquinone of strain SZ4R5S7 T was MK-8(H4), and the major fatty acids were iso-C16 : 0 and anteiso-C14 : 0. The DNA G+C content was determined to be 72.4 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain SZ4R5S7 T belongs to the genus Nocardioides and showed highest levels of 16S rRNA gene sequence similarity to members of the strain Nocardioideskribbensis KSL-2 T (97.8 %). On the basis of phenotypic, genotypic and phylogenetic data, strain SZ4R5S7 T represents a novel species in the genus Nocardioides, for which the name Nocardioides ferulae sp. nov. is proposed and the type strain is SZ4R5S7 T (=CGMCC 4.7456 T =KCTC 39994 T ).

A gene encoding a β-xylosidase (designated as Thxyl43A) was cloned from strain Thermobifida halotolerans YIM 90462 T . The open reading frame of this gene encodes 550 amino acid residues. The gene was over-expressed in Escherichia coli and the recombinant protein was purified. The monomeric Thxyl43A protein presented a molecular mass of 61.5 kDa. When p-nitrophenyl-β-d-xylopyranoside was used as the substrate, recombinant Thxyl43A exhibited optimal activity at 55 °C and pH 4.0 to 7.0, being thermostable by maintaining 47% of its activity after 30 h incubation at 55 °C. The recombinant enzyme retained more than 80% residual activity after incubation at pH range of 4.0 to 12.0 for 24 h, respectively, which indicated notable thermostability and pH stability of Thxyl43A. Moreover, Thxyl43A displayed high catalytic activity (> 60%) in presence of 5-35% NaCl (w/v) or 1-20% ionic liquid (w/v) or 1-50 mM xylose. These properties suggest that Thxyl43A has potential for promoting hemicellulose degradation and other industrial applications.

Two bacterial strains, YZYP 306 T and YZGP 509, were isolated from the halophyte Suaeda aralocaspica collected from the southern edge of the Gurbantunggut desert, north-west China. Cells were Gram-stain-positive, aerobic, non-motile, short rods. Strain YZYP 306 T grew at 4-40 °C, while strain YZGP 509 grew at 4-42 °C, with optimum growth at 28 °C, and they both grew at pH 6.0-12.0 and 0-15 % (w/v) NaCl. Phylogenetic analyses of the 16S rRNA gene sequences placed the two strains within the genus Microbacterium with the highest similarities to Microbacterium indicum BBH6 T (97.8 %) and Microbacterium sorbitolivorans SZDIS-1-1 T (97.2 %). The average nucleotide identity value between YZYP 306 T and M. indicum BBH6 T was 78.3 %. The genomic DNA G+C contents of strains YZYP 306 T and YZGP 509 were 68.49 and 68.53 mol%, respectively. The characteristic cell-wall amino acid was ornithine. Whole-cell sugars were galactose, mannose and ribose. The acyl type of the peptidoglycan was glycolyl. The major cellular fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The major menaquinones were MK-10 and MK-11. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, an unidentified phospholipid and an unidentified glycolipid. These results are consistent with the classification of the two strains into the genus Microbacterium. On the basis of the evidence presented in this study, strains YZYP 306 T and YZGP 509 are representatives of a novel species in the genus Microbacterium, for which the name Microbacterium suaedae sp. nov. is proposed. The type strain is YZYP 306 T (=CGMCC 1.16261 T =KCTC 49101 T ).

A non-motile, coccobacilli-shaped and yellow-coloured bacterium, designated strain SYSU D60003 T , was isolated from a desert soil sample. Cells were Gram-stain-positive, catalase-negative and oxidase-positive. The whole cell hydrolysates contained ll-diaminopimelic acid as the diagnostic amino acid. The major fatty acids were C16 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and iso-C16 : 0. The respiratory menaquinones were MK-9(H8), MK-9(H4) and MK-9(H6). The DNA G+C content was determined to be 70.2 % (genome). The polar lipids detected were diphosphatidylglycerol, an unidentified glycolipid and seven unidentified polar lipids. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SYSU D60003 T belonged to the order Acidimicrobiales (class Acidimicrobiia), but formed a clade closely linked to members of the genus Ilumatobacter. Data from a polyphasic taxonomy study suggested that the isolate represents a novel species of a novel genus in the order Acidimicrobiales, for which the name Desertimonas flava gen. nov., sp. nov. is proposed. The type strain of the proposed new taxon is SYSU D60003 T (=KCTC 39917 T =NBRC 112924 T ). Additionally, the new taxon along with the genus Ilumatobater (family unassigned) were distinctly separated from the related families Acidimicrobiaceae, Iamiaceae and 'Microtrichaceae' in the phylogenetic trees, besides presenting a unique 16S rRNA gene signature nucleotides. Therefore, we propose a new family Ilumatobacteraceae fam. nov. within the order Acidimicrobiales to accommodate members of these two genera.

A draft genome sequence of Jiangella alba YIM 61503 T revealed a genome size of 7,664,864 bp arranged in 33 scaffolds. The genome was predicted to contain 7196 predicted genes, including 51 coding for RNA. Phylogenetic and comparative analyses of the draft genome of J. alba YIM 61503 T with the available genomes of other Jiangella species suggested a proximal similarity between strains J. alba YIM 61503 T and J. muralis DSM 45357 T , while indicating a high divergence between J. gansuensis YIM 002 T and other Jiangella species. The genome of J. alba YIM 61503 T also revealed genes involved in indole-3-acetic acid biosynthesis and an alkylresorcinols gene cluster. Further, detection of phosphotransferase genes in the genome of all Jiangella species indicated that they can uptake and phosphorylate sugars. The presences of TreX-Z, TreS and OtsA-OtsB genes in some of the Jiangella strains also indicated a possible mechanism for their tolerance of high salinity. Besides providing new insights into its genetic features, our results suggested that J. alba YIM 61503 T could be a potential strain for further genome mining studies. The release of this genome may, therefore, provide a better prospect for understanding "evolutionary taxonomy" about this genus in future.

Strains SYSU D8007 T and SYSU D8014 T were isolated from desert soil collected from Saudi Arabia. The two isolates were Gram-stain-positive, non-motile, aerobic and non-spore-forming. These strains were able to grow at 4-45 °C and in the presence of up to 8 % (w/v) NaCl. Strain SYSU D8007 T could grow at pH 6.0-10.0, and strain SYSU D8014 T at pH 5.0-10.0. They shared highest 16S rRNA gene sequence similarities with Microbacterium marinilacus YM11-607 T and Microbacterium paludicola US15 T . Menaquinones MK-11 and MK-12 were detected as the respiratory quinones. The polar lipid profiles of strains SYSU D8007 T and SYSU D8014 T consisted of diphosphatidylglycerol and phosphatidylglycerol, but differed in the number of unidentified glycolipids. Strain SYSU D8007 T contained anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0 as the predominant fatty acids, while strain SYSU D8014 T contained anteiso-C15 : 0 and anteiso-C17 : 0 as the major fatty acids (>10 %). While glucose, rhamnose and ribose were detected in strain SYSU D8007 T as the whole-cell sugars, galactose, glucose and rhamnose were present in strain SYSU D8014 T . The genomic DNA G+C content of strains SYSU D8007 T and SYSU D8014 T was 72.2 and 73.6 mol%, respectively. Based on phenotypic, genotypic and phylogenetic characteristics, it can be concluded that strains SYSU D8007 T and SYSU D8014 T represent two novel species of the genus Microbacterium, for which the names Microbacterium album sp. nov. and Microbacterium deserti sp. nov. are proposed, respectively. The type strains are SYSU D8007 T (=CGMCC 1.15794 T =KCTC 39990 T ) and SYSU D8014 T (=CPCC 204619 T =KCTC39991 T ).

A xylanase gene (TrXyn10) from Thermoactinospora rubra YIM 77501 T was cloned and expressed in Escherichia coli. The amino acid sequence displayed 78% homology with Microbispora mesophila xylanase (WP_062413927.1). The recombinant xylanase (TrXyn10), with MW 46.1 kDa, could hydrolyse beechwood, birchwood and oatspelt xylan. Based on the sequence, enzymatic properties and tertiary structure of the protein, TrXyn10 belongs to glycoside hydrolase family 10 (GH10). The optimal pH and temperature for the recombinant enzyme were determined to be 7.0 and 55 °C, respectively. TrXyn10 was stable over a wide pH range, and it retained more than 45% of the total activity at pH 6.0-12.0 for 12 h. In addition, the activity was greatly promoted, by approximately 200% of the initial activity, after incubation at pH 6.0 and 7.0 for 12 h. Based on enzymatic properties and product analysis, we showed that TrXyn10 is a neutral endoxylanase.

A novel actinobacterium, designated strain JXJ CY 01 T , was isolated from a mucilaginous sheath of Microcystis aeruginosa FACHB-905 collected from Lake Dianchi, south-west China. Taxonomic position of the isolate was determined by polyphasic approaches. Strain JXJ CY 01 T shared 16S rRNA sequence similarities of 98.9 and 98.0% with Microbacterium marinilacus YM11-607 T and Microbacterium paludicola US15 T , and less than 98% with other members of the genus Microbacterium. The DNA-DNA relatedness values between strains JXJ CY 01 T and M. marinilacus JCM 16546 T and M. paludicola JCM 14308 T were 53.5±1.4 and 53.8±2.1%, respectively. l-Ornithine was detected in the cell wall, and rhamnose, galactose, glucose, arabinose, fucose and mannose as signature sugars in the whole-cell hydrolysates. Other chemotaxonomic characteristics determined were MK-12 and MK-11 as predominant menaquinones, anteiso-C 15:0 , iso-C 16:0 , anteiso-C 17:0 and iso-C 17:0 as major cellular fatty acids (>10%), and diphosphatidylglycerol, phosphatidylglycerol, an unidentified glycolipid and two unidentified phospholipids as the polar lipids. The DNA G+C content was 70.4 mol%. On the basis of the above taxonomic data, strain JXJ CY 01 T is determined to represent a novel species of the genus Microbacterium, for which the name Microbacterium lacusdiani sp. nov. is proposed. The type strain is JXJ CY 01 T (= KCTC 29655 T =DSM 29188 T ). The type strain JXJ CY 01 T can solubilize both insoluble inorganic (calcium phosphate) and organic phosphate (l-α-phosphatidylcholine) and is possibly one of the mechanism for enhancement of growth of M. aeruginosa FACHB-905.

Dracaena cochinchinensis Lour. is an ethnomedicinally important plant used in traditional Chinese medicine known as dragon's blood. Excessive utilization of the plant for extraction of dragon's blood had resulted in the destruction of the important niche. During a study to provide a sustainable way of utilizing the resources, the endophytic Actinobacteria associated with the plant were explored for potential utilization of their medicinal properties. Three hundred and four endophytic Actinobacteria belonging to the genera Streptomyces , Nocardiopsis , Brevibacterium , Microbacterium , Tsukamurella , Arthrobacter , Brachybacterium , Nocardia , Rhodococcus , Kocuria , Nocardioides , and Pseudonocardia were isolated from different tissues of D. cochinchinensis Lour. Of these, 17 strains having antimicrobial and anthracyclines-producing activities were further selected for screening of antifungal and cytotoxic activities against two human cancer cell lines, MCF-7 and Hep G2. Ten of these selected endophytic Actinobacteria showed antifungal activities against at least one of the fungal pathogens, of which three strains exhibited cytotoxic activities with IC 50 -values ranging between 3 and 33  μ g·mL -1 . Frequencies for the presence of biosynthetic genes, polyketide synthase- (PKS-) I, PKS-II, and nonribosomal peptide synthetase (NRPS) among these 17 selected bioactive Actinobacteria were 29.4%, 70.6%, and 23.5%, respectively. The results indicated that the medicinal plant D. cochinchinensis Lour. is a good niche of biologically important metabolites-producing Actinobacteria.

An alkalitolerant actinomycete strain, designated EGI 80674T, was isolated from a rhizosphere soil of Halocnermumstrobilaceum (Pall.) Bieb in Xinjiang, north-west China and subjected to a taxonomic characterization using a polyphasic approach. Strain EGI 80674T formed white aerial hyphae with long spore chains. Whole-cell hydrolysates of the isolate contained meso-diaminopimelic acid as the diagnostic diamino acid with no diagnostic sugars. The major fatty acids identified were iso-C16 : 0, anteiso-C17 : 0 and 10-methyl-C18 : 0TBSA. The predominant menaquinones detected were MK-10(H8) and MK-10(H6). The G+C content of the genomic DNA of strain EGI 80674T was 70.9 mol%. Strain EGI 80674T showed the highest 16S rRNA gene sequence similarity (97.24 %) to Nocardiopsis nikkonensis NBRC 102170T. The DNA-DNA relatedness value of strain EGI 80674T and N. nikkonensis NBRC 102170T was 18.4±1.3 %. Phenotypical, chemotaxonomic and phylogenetic characteristics and DNA-DNA hybridization data suggest that strain EGI 80674T represents a novel species of the genus Nocardiopsis, for which the name Nocardiopsis rhizosphaerae sp. nov. is proposed. The type strain is EGI 80674T (=CGMCC 4.7228T=KCTC 39673T).

Two novel actinomycetes, designated strains CFH S0322 T and CFH S01580 T , were isolated from soil samples collected from Xuchang city and Ji Guan cave in Henan province, China, respectively. Their taxonomic positions were investigated by a polyphasic approach. The two isolates were Gram-reaction positive, non-motile, aerobic and catalase-positive actinomycetes. Phylogenetic analysis based on 16S rRNA gene sequence comparisons showed that the two isolates are closely related to the members of the genus Amycolatopsis, sharing high similarities with Amycolatopsis magusensis KCTC 29056 T (99.1 %, CFH S0322 T ) and Amycolatopsis nigrescens DSM 44992 T (98.1 %, CFH S01580 T ), respectively. The major whole cell sugars of strains CFH S0322 T and CFH S01580 T were arabinose and galactose and the predominant menaquinone was MK-9(H 4 ). The genomic DNA G+C contents of strains CFH S0322 T and CFH S01580 T were 70.6 and 68.6 mol%, respectively. Morphological, phylogenetic and chemotaxonomic results suggest that strains CFH S0322 T and CFH S01580 T are representatives of two new species, for which the names Amycolatopsis xuchangensis sp. nov. and Amycolatopsis jiguanensis sp. nov. are proposed. The type strains are CFH S0322 T (=NBRC 110769 T  =KCTC 39516 T ) and CFH S01580 T (=DSM 101526 T  =CCTCC AA 2015032 T ).

A novel actinobacterium, designated strain JXJ CY 19T, was isolated from a culture mat of Microcystis aeruginosa FACHB-905 collected from Dianchi Lake, South-west China. 16S rRNA gene sequences comparison of strain JXJ CY 19T and the available sequences in the GenBank database showed that the strain was closely related to Modestobacter marinus 42H12-1T (99.1% similarity) and Modestobacter roseus KLBMP 1279T (99.0%). The isolate had meso-diaminopimelic in the cell wall with whole-cell sugars of mannose, rhamnose, ribose, glucose, galactose, and arabinose. The menaquinone detected was MK-9(H4), while the major cellular fatty acids include C17:1 ω8c, C15:0 iso, C15:1 iso G and C16:0 iso. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside and an unidentified phospholipid. The DNA-DNA hybridization values between strains JXJ CY 19T and the closely related type strains Modestobacter marinus CGMCC 4.5581T and Modestobacter roseus NBRC 108673T were determined to be 50.8 ± 0.8% and 44.1 ± 1.7%, respectively. The DNA G+C content was 71.9 mol%. On the basis of the above taxonomic data and differences in physiological characters from the closely related type strains, strain JXJ CY 19T was recognized as a novel species of the genus Modestobacter, for which the name Modestobacter lacusdianchii sp. nov. (JXJ CY 19T = KCTC 39600T = CPCC 204352T) is proposed. The type strain JXJ CY 19T can solubilize calcium phosphate tribasic (Ca3(PO4)2), phytin and L-α-phosphatidylcholine. The phosphate-solubilizing property of the novel actinobacterium could be a possible factor for the increase in growth of Microcystis aeruginosa FACHB-905 in ecosystem where the amount of available soluble phosphate is limited such as Dianchi Lake.

The class Actinobacteria has been a goldmine for the discovery of antibiotics and has attracted interest from both academics and industries. However, an absence of novel approaches during the last few decades has limited the discovery of new microbial natural products useful for industries. Scientists are now focusing on the ecological aspects of diverse environments including unexplored or underexplored habitats and extreme environments in the search for new metabolites. This paper reports on the diversity of culturable actinobacteria associated with hot springs located in Tengchong County, Yunnan Province, southwestern China. A total of 58 thermophilic actinobacterial strains were isolated from the samples collected from ten hot springs distributed over three geothermal fields (e.g., Hehua, Rehai, and Ruidian). Phylogenetic positions and their biosynthetic profiles were analyzed by sequencing 16S rRNA gene and three biosynthetic gene clusters (KS domain of PKS-I, KSα domain of PKS-II and A domain of NRPS). On the basis of 16S rRNA gene phylogenetic analysis, the 58 strains were affiliated with 12 actinobacterial genera: Actinomadura Micromonospora, Microbispora, Micrococcus, Nocardiopsis, Nonomuraea, Promicromonospora, Pseudonocardia, Streptomyces, Thermoactinospora, Thermocatellispora, and Verrucosispora, of which the two novel genera Thermoactinospora and Thermocatellisopora were recently described from among these strains. Considering the biosynthetic potential of these actinobacterial strains, 22 were positive for PCR amplification of at least one of the three biosynthetic gene clusters (PKS-I, PKS-II, and NRPS). These actinobacteria were further subjected to antimicrobial assay against five opportunistic human pathogens (Acinetobacter baumannii, Escherichia coli, Micrococcus luteus, Staphylococcus aureus and Streptococcus faecalis). All of the 22 strains that were positive for PCR amplification of at least one of the biosynthetic gene domains exhibited antimicrobial activities against at least one of the five test organisms. Among the remaining 36 actinobacteria that are negative for PCR amplification of the domains for the biosynthetic genes, 33 strains showed antimicrobial activities against at least one of the five test pathogens. In summary, the findings presented in this study emphasized the importance of underexplored habitats such as Tengchong hot springs as potential sources for search of bioactive molecules.

A novel actinobacterial strain, YIM ART06T, was isolated from a rock sample of karst cave located at Guizhou province, south-west China, and was characterized by a polyphasic taxonomic approach. The morphological and chemotaxonomic properties of strain YIM ART06T were in accordance with those of the genus Stackebrandtia. The 16S rRNA gene sequence of strain YIM ART06T showed highest similarity to Stackebrandtia nassauensis JCM 14905T (98.0 %). The DNA-DNA hybridization value between strains YIM ART06T and S. nassauensis JCM 14905T was, however, moderately high (62.9 %) but below the 70 % limit for species identification. Strain YIM ART06T contained meso-diaminopimelic acid as the diagnostic diamino acid, and mannose, ribose and xylose in the whole-cell hydrolysates. The predominant menaquinones detected were MK-10(H4), MK-10(H6), MK-11(H4) and MK-11(H6), while the cell membrane polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylmethylethanolamine and three unidentified phospholipids. The genomic DNA G+C content of strain YIM ART06T was 71 mol%. The major fatty acids were anteiso-C17 : 0, iso-C17 : 0, iso-C16 : 0 and iso-C15 : 0. Based on the taxonomic characteristics from the genotypic and phenotypic results, strain YIM ART06T merits recognition as a representative of a novel species of the genus Stackebrandtia, for which the name Stackebrandtia cavernae sp. nov. is proposed. The type strain is YIM ART06T ( = KCTC 39599T = CCTCC AA 2015021T = DSM 100594T).

A novel Gram-stain-positive, non-motile, moderately halophilic and alkalitolerant actinobacterium, designated EGI 80432T, was isolated from a saline-alkaline soil of Xinjiang province, north-west China. Cells were non-endospore-forming cocci with a diameter of 0.5-0.8 μm. Strain EGI 80432T grew in the presence of 0-9 % (w/v) NaCl (optimum at 3-5 %), and also grew within the pH range 6.0-10.0 (optimum at pH 8.0-9.0) on marine 2216E medium. The peptidoglycan type was A1γ. The whole-cell hydrolysates contained glucose, galactose, mannose and three unknown sugars as major sugars. The predominant menaquinone was MK-9(H4). The major fatty acids were C17 : 1ω8c, summed feature 3 (C16 : 1ω7c/C16 : 1ω6c), C18 : 1ω9c and iso-C15 : 0 The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, one unknown phosphoglycolipid, three unknown phospholipids and four unknown polar lipids. The genomic DNA G+C content was 75.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain EGI 80432T clustered within the radius of the class Nitriliruptoria. Levels of sequence similarity between strain EGI 80432T and its phylogenetic neighbours Nitriliruptor alkaliphilus ANL-iso2T and Euzebya tangerina F10T were 94.1 and 88.1 %, respectively. Based on morphological, physiological and chemotaxonomic characteristics and phylogenetic analysis, a novel species of a new genus, Egicoccus halophilus gen. nov., sp. nov., is proposed, within the new family and new order Egicoccaceae fam. nov. and Egicoccales ord. nov. in the class Nitriliruptoria. The type strain of Egicoccus halophilus is EGI 80432T ( = CGMCC 1.14988T = KCTC 33612T).

A novel obligately halophilic, facultatively alkaliphilic actinobacterium, designated EGI 80759T, was isolated from the rhizosphere of Tamarix hispida Willd, Karamay, Xinjiang province, north-west China. Cells of strain EGI 80759T were Gram-stain-positive, non-motile and non-endospore-forming rods. Strain EGI 80759T showed obligately halophilic growth with a tolerance to 8-25 % (w/v) NaCl (optimum growth at 10-12 %, w/v) and facultatively alkaliphilic growth within the pH range 7.0-11.0 (optimum growth at pH 9.0-10.0). Cell-wall hydrolysates of the isolate contained meso-diaminopimelic acid (peptidoglycan type A1γ), with glucose, glucosamine, ribose and mannose as the major sugars. The major fatty acids identified were 10-methyl-C17 : 0, C17 : 1ω8c and C17 : 0. The predominant menaquinone was MK-9(H4). The G+C content of the genomic DNA was 72.1 mol%. Phylogenetic analysis, based on 16S rRNA gene sequences, revealed that strain EGI 80759T clustered with members of the class Nitriliruptoria and showed highest 16S rRNA gene sequence similarities with Euzebya tangerina F10T (90.3 %) and Nitriliruptor alkaliphilus ANL-iso2T (88.1 %). On the basis of the data obtained from phenotypic and chemotaxonomic studies and the phylogenetic analysis, the isolate is proposed to be a representative of a novel genus and a novel species, Egibacter rhizosphaerae gen. nov., sp. nov., of a proposed novel family, Egibacteraceae fam. nov., and order, Egibacterales ord. nov., within the class Nitriliruptoria. The type strain of the type species, Egibacter rhizosphaerae, is EGI 80759T ( = CGMCC 1.14997T = KCTC 39588T).

A novel actinomycete strain, designated YIM LPA2h(T), was isolated from a sediment sample collected from Lop Nur, Xinjiang Uygur Autonomous Region, North-West China. The taxonomic position of strain YIM LPA2h(T) was investigated by a polyphasic approach. The morphological and chemotaxonomic properties of the isolate were in accordance with the members of the genus Saccharothrix. The 16S rRNA gene sequence of the strain showed highest similarities to Saccharothrix yanglingensis (98.6 %), Saccharothrix longispora (98.4 %) and Saccharothrix hoggarensis (98.3 %). However, the DNA-DNA hybridization values between the new isolate YIM LPA2h(T) and S. yanglingensis, S. longispora and S. hoggarensis were significantly below 70 %. Strain YIM LPA2h(T) was found to contain meso-diaminopimelic acid as diagnostic diamino acid. The major sugars in whole-cell hydrolysates were rhamnose, galactose, mannose, glucose and fructose. The major polar lipids were identified as phosphatidylethanolamine, phosphatidylhydroxylethanolamine, diphosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannoside. The predominant respiratory menaquinones were MK-9 (H4) and MK-10 (H4). The major fatty acids were C17:1 ω8c (15 %), iso-C15:0 (12 %), anteiso-C15:0 (12 %) and summed feature 3 (C16:1 ω6c/C16:1 ω7c, 10 %). The genomic DNA G+C content of strain YIM LPA2h(T) was determined to be 75 mol %. The genotypic and phenotypic results suggest that strain YIM LPA2h(T) represents a novel species of the genus Saccharothrix, for which the name Saccharothrix lopnurensis sp. nov. is proposed. The type strain is YIM LPA2h(T) (=CGMCC 4.7246(T)=KCTC 39545(T)).

Two Gram-staining positive, aerobic and non-motile actinomycete strains, designated YIM 2047X(T) and YIM 2047D, were isolated from tobacco root samples collected from Shiling county, Yunnan province, South-West China. The isolates grew at 15-40 °C, pH 6.0-8.0 and 0-4.5 % NaCl (w/v). The whole-cell hydrolysates contained meso-diaminopimelic acid, galactose, mannose, ribose and rhamnose. The polar lipids detected were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside. The major cellar fatty acids identified were iso-C14:0, iso-C15:0, anteiso-C15:0, iso-C16:0, C16:0, C17:1 ω8c and C17:0. MK-9 (H4) was the predominant menaquinone. The genomic DNA G+C contents were 73.4 and 74.2 mol%, respectively. These chemotaxonomic data, together with their morphological properties, were consistent with the assignment of the two strains to the genus Umezawaea. They showed highest similarities to Umezawaea tangerina JCM 10302(T) on phylogenetic analysis of their 16S rRNA gene sequences and were found to form a coherent cluster. However, the DNA-DNA hybridization values of YIM 2047X(T) and YIM 2047D with U. tangerina JCM 10302(T) were 46.5 ± 3.1 and 57.5 ± 1.6 %, respectively; while the reassociation value between themselves was 80.4 ± 2.3 %. The results of physiological and biochemical tests allowed the two new isolates to be differentiated phenotypically from the recognized strain U. tangerina JCM 10302(T). On the basis of results from this polyphasic study, the strains were characterized as a novel species of the genus Umezawaea, for which the name Umezawaea endophytica sp. nov. is proposed. The type strain is YIM 2047X(T) (=KCTC 39538(T) = CPCC 204132(T)).

A Gram-positive, aerobic, nonmotile actinomycete strain designated DRQ-2(T) was isolated from the soil sample collected from lime-stone open pit mine from the Gulbarga region, Karnataka province, India. Strain DRQ-2(T) was identified as a member of the genus Nonomuraea by a polyphasic approach. Strain DRQ-2(T) could be differentiated from other members of the genus Nonomuraea on the basis of physiology and 16S rRNA gene sequence analysis. The 16S rRNA gene sequence similarity of strain DRQ-2(T) showed highest sequence similarity to Nonomuraea muscovyensis DSM 45913(T) (99.1%), N. salmonea DSM 43678(T) (98.2%) and N. maheshkhaliensis JCM 13929(T) with 98.0%, respectively. Chemotaxonomic properties showing predominant menaquinones of MK-9 (H4), MK-9(H2) and MK-9(H6), major polar lipids comprised diphosphatidylglycerol, phosphatidylmono methyl ethanolamine (PME), phosphatidylethanolamine (PE), hydroxy-PME (OH-PME), hydroxy PE (OH-PEE), phosphatidylglycerol (PG), ninhydrin-positive phosphoglycolipid and unknown phospholipid, fatty acids with major amounts of i-C16:0, ai-C15:0 and ai-C17:0 supported allocation of the strain to the genus Nonomuraea. Results of DNA-DNA hybridization and physiological tests allowed genotypic and phenotypic differentiation of strain DRQ-2(T) from closely related species. The genomic DNA G+C content of the organism was 72.5 mol%. On the basis of phenotypic, chemotypic and molecular characteristics, strain DRQ-2(T) represents a novel species of the genus Nonomuraea, for which the name N. indica sp. nov. is proposed, with type strain DRQ-2(T) (=NCIM 5480(T)= CCTCC AA 209050(T)).

Two aerobic, Gram-positive actinomycetes, designated YIM 77502(T) and YIM 77510(T), were isolated from geothermally heated soil of Tengchong county, Yunnan province, south-west China. The taxonomic position of strains YIM 77502(T) and YIM 77510(T) were investigated by a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains YIM 77502(T) and YIM 77510(T) belong to the genus Actinomadura. Both strains form extensively-branched substrate and aerial mycelia which differentiated into short spore chains. The cell wall of the two strains contained meso-diaminopimelic acid, while the whole-cell sugars detected were glucose, madurose, mannose and rhamnose. The polar lipid profile of strain YIM 77502(T) was found to consist of diphosphatidylglycerol, phosphatidylinositol mannoside, phosphatidylinositol, two unidentified phospholipids and an unidentified polar lipid, while strain YIM 77510(T) consisted of diphosphatidylglycerol, phosphatidylinositol mannoside and phosphatidylinositol. The respiratory quinones of strains YIM 77502(T) and YIM 77510(T) were MK-9(H6) and MK-9(H8). The major fatty acids (>10 %) of strain YIM 77502(T) were C17:0, iso-C16:0, C17:010-methyl and iso-C18:0, and those of strain YIM 77510(T) were iso-C16:0, C17:010-methyl and iso-C18:0. The G+C contents of strains YIM 77502(T) and YIM 77510(T) were determined to be 71.3 and 70.2 mol%, respectively. The DNA-DNA hybridization values of strains YIM 77502(T), YIM 77510(T) and their closest phylogenetic neighbours Actinomadura echinospora BCRC 12547(T) and Actinomadura umbrina KCTC 9343(T) were less than 70 %. Based on the morphological and physiological properties, and phylogenetic analyses, strains YIM 77502(T) and YIM 77510(T) are considered to represent two novel species of the genus Actinomadura, for which the names Actinomadura amylolytica sp. nov. (type strain YIM 77502(T) = DSM 45822(T) = CCTCC AA 2012024(T)) and Actinomadura cellulosilytica sp. nov. (type strain YIM 77510(T) = DSM 45823(T) = CCTCC AA 2012023(T)) are proposed.

A novel endophytic actinobacterium, designated strain YIM 690053(T), was isolated from healthy stems of Salsola ferganica Drob, and was characterized using a polyphasic taxonomic approach. The strain formed well-branched substrate mycelia with no fragmentation, and abundant aerial mycelia that differentiated into long spores. The strain was found to grow at 10-55 °C, pH 6.0-10.0 and in the presence of 0-7 % (w/v) NaCl. The genomic DNA G+C content was determined to be 70.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM 690053(T) belongs to the genus Marinactinospora, and it shared the highest 16S rRNA gene sequence similarity with Marinactinospora thermotolerans SCSIO 00652(T) (98.96 %). However, the DNA-DNA relatedness values between the two strains was 37.85 ± 2.77 %. Based on the differences in the molecular and biochemical characteristics from its closest relative, strain YIM 690053(T) is concluded to represent a novel species of the genus Marinactinospora, for which the name Marinactinospora endophytica sp. nov. is proposed. The type strain is YIM 690053(T)(=KCTC 29664(T) = DSM 46799(T)).

A novel endoglucanase gene was cloned from Thermobifida halotolerans YIM 90462(T), designated as thcel6A for being a member of glycoside hydrolase family 6. The gene was 1332 bp long and encoded a 443-amino-acid protein with a molecular mass of 45.9 kDa. The purified recombinant endoglucanase had optimal activity at 55 °C and pH 8.5. Thcel6A showed high hydrolytic activities at 25-55 °C and retained 58% of initial activity after incubation at 90 °C for 1 h. It retained more than 80% of activity after incubation for 12 h at pH values from 4 to 12. Thcel6A displayed higher hydrolytic activities in 5-15% NaCl (w/v) than at 0% NaCl. Activity increased 2.5-fold after incubation with 20% (w/v) NaCl at 37 °C for 10 min. These properties suggest that this novel endoglucanase has potential for specific industrial application.

A white bacterial strain, designated EGI 650022(T), was isolated from the roots of Salsola affinis C. A. Mey, collected from Urumqi City, Xinjiang, north-western China. The strain was found to be aerobic, Gram-stain positive, oxidase-positive and catalase-positive. Cells were non-motile and irregular rods. Growth occurred at NaCl concentrations between 0 and 7 % (w/v), temperatures between 5 and 45 °C, and pH 6.0-9.0. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain EGI 650022(T) belongs to a clade with the genera Okibacterium and Plantibacter in the family Microbacteriaceae. The novel strain EGI 650022(T) showed highest levels of 16S rRNA gene sequence similarity with members of the genera Okibacterium and Plantibacter (97.2-98.0 %). The cell-wall peptidoglycan contained glutamate, homoserine, glycine, alanine and lysine. The predominant menaquinones (MKs) were MK-11, MK-12 and MK-12 (H4). The polar lipid pattern comprised phosphatidylglycerol, diphosphatidylglycerol, two unknown glycolipids and two unknown phospholipids. The major fatty acids were anteiso-C15:0 and anteiso-C17:0. The DNA G+C content was 66.0 mol%. The DNA-DNA relatedness values of strain EGI 650022(T) with Okibacterium fritillariae DSM 12584(T), Plantibacter flavus DSM 14012(T) and Plantibacter auratus DSM 19586(T) were 39.7, 19.7 and 22.0 %. Based on phylogenetic, phenotypic, chemotaxonomic and DNA-DNA hybridization data, strain EGI 650022(T) is considered to represent a novel species of the genus Okibacterium, for which the name Okibacterium endophyticum sp. nov. is proposed; the type strain is EGI 650022(T) (=JCM 30086(T) = KCTC 29492(T)).

A Gram-stain-positive, aerobic, non-motile, coryneform bacterium, designated strain EGI 60002(T), was isolated from the halophyte Suaeda physophora. Cells were coryneform shaped and polymorphic. Phylogenetic analysis based on 16S rRNA gene sequences showed that the new isolate was closely related to Actinotalea ferrariae CF5-4(T) (95.8 % gene sequence similarity). The peptidoglycan type of strain EGI 60002(T) was A4β, containing L-Orn-D-Ser-D-Asp. The cell-wall sugars were mannose, ribose, rhamnose and glucose. The major fatty acids (>5 %) of strain EGI 60002(T) were iso-C14:0, iso-C15:0, anteiso-C15:1 A and anteiso-C15:0. The predominant respiratory quinone was MK-10(H4). The major polar lipids were diphosphatidylglycerol (DPG), one unidentified phosphoglycolipid (PGL) and one unidentified phospholipid (PL1). The genomic DNA G+C content was 72.3 mol%. On the basis of morphological, physiological, chemotaxonomic data, and phylogenetic analysis, strain EGI 60002(T) should be classified as a novel species within the genus Actinotalea, for which the name Actinotalea suaedae sp. nov. is proposed. The type strain is EGI 60002T (=JCM 19624(T) = KACC 17839(T) = KCTC 29256(T)).

A Gram-stain positive, yellow-coloured, aerobic, non-motile, catalase-positive and oxidase-negative, endophytic actinobacterium, designated strain EGI 6500705(T), was isolated from the surface-sterilized stem of a halophyte Anabasis elatior (C. A. Mey.) Schischk collected from Urumqi, Xinjiang province, north-west China. The organism had ornithine as the diagnostic cell-wall diamino acid. The major fatty acids were anteiso-C15:0, anteiso-C17:0 and iso-C16:0. The predominant menaquinones were MK-9, MK-10 and MK-11. The DNA G + C content of strain EGI 6500705(T) was 69.2 mol%. Phylogenetic analyses based on 16S rRNA gene sequence showed that strain EGI 6500705(T) is clearly affiliated with the genus Labedella and most closely related to Labedella gwakjiensis KCTC 19176(T), with 99.0 % sequence similarity. DNA-DNA relatedness between strain EGI 6500705(T) and L. gwakjiensis KCTC 19176(T) was 27.4 %. On the basis of phenophytic, chemotaxonomic and phylogenetic analysis, the strain EGI 6500705(T) represents a novel species of the genus Labedella, for which the name Labedella endophytica sp. nov. is proposed. The type strain is EGI 6500705(T) (=KCTC 29494(T) = CPCC 203961(T) = JCM 30092(T)).

A Gram-stain positive, aerobic, non-motile and rod-shaped actinobacterial strain, designated as ZYR 51(T), was isolated from pharmaceutical wastewater in Jinhua city, Zhejiang province, Eastern China. Isolation was aided by using a resuscitation-promoting factor, suggesting the strain was recovered from a viable but non-culturable state. Strain ZYR 51(T) was characterized by a polyphasic taxonomic approach. Growth was found to occur at 10-45 °C, pH 6.0-10.0 and 0-9 % NaCl (w/v). Based on the 16S rRNA gene sequence, phylogenetic analysis clearly demonstrated that strain ZYR 51(T) belongs to the genus Gordonia and showed low level similarities (below 97 %) with all other members of this genus. The strain was found to possess meso-diaminopimelic acid (meso-DAP), along with MK-9(H2) as the predominant menaquonine. Mycolic acids were found to be present. C16:0 (34.9 %), 10-methyl C18:0 (30.3 %), iso-C18:0(8.2 %), and summed feature 3 (C16:1 ω6c and/or C16:1ω7c as define by MIDI; 18.8 %) were identified as the major cellular fatty acids. The polar lipid profile of strain ZYR 51(T) was found to consist of diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannosides and some unknown lipids. The genomic DNA G+C content of strain ZYR 51(T) was determined to be 67.7 mol%. The combined genotypic and phenotypic data showed that the strain represents a novel species of the genus Gordonia, for which the name Gordonia jinhuaensis sp. nov. is proposed, with the type strain is ZYR 51(T) (=CGMCC 1.12827(T) = NBRL B-59111(T) = NBRC 110001(T)).