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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.)

Bio-fertilizer practice considers not only economical but also environmentally friendly, sustainable agriculture. Endophytes can play important beneficiary roles in plant development, directly, indirectly, or synergistically. In this study, the majority of our endophytic actinobacteria were able to possess direct plant growth-promoting (PGP) traits, including auxin (88%), ammonia (96%), siderophore production (94%), and phosphate solubilization (24%), along with cell-wall degrading enzymes such as protease (75%), cellulase (81%), lipase (81%), and chitinase (18%). About 45% of tested strains have an inhibitory effect on the phytopathogen Fusarium oxysporum, followed by 26% for Verticillium dahlia. Overall, our results showed that strains XIEG63 and XIEG55 were the potent strains with various PGP traits that caused a higher significant increase (p ≤ 0.05) in length and biomass in the aerial part and roots of tomato and cotton, compared to the uninoculated plants. Our data showed that the greatest inhibition percentages of two phytopathogens were achieved due to treatment with strains XIEG05, XIEG07, XIEG45, and XIEG51. The GC-MS analysis showed that most of the compounds were mainly alkanes, fatty acid esters, phenols, alkenes, and aromatic chemicals and have been reported to have antifungal activity. Our investigation emphasizes that endophytic actinobacteria associated with medicinal plants might help reduce the use of chemical fertilization and potentially lead to increased agricultural productivity and sustainability. [ABSTRACT FROM AUTHOR]

Bacterial endophytes are well-acknowledged inoculants to promote plant growth and enhance their resistance toward various pathogens and environmental stresses. In the present study, 71 endophytic strains associated with the medicinal plant Thymus roseus were screened for their plant growth promotion (PGP), and the applicability of potent strains as bioinoculant has been evaluated. Regarding PGP traits, the percentage of strains were positive for the siderophore production (84%), auxin synthesis (69%), diazotrophs (76%), phosphate solubilization (79%), and production of lytic enzymes (i.e., cellulase (64%), lipase (62%), protease (61%), chitinase (34%), and displayed antagonistic activity against Verticillium dahliae (74%) in vitro. The inoculation of strain XIEG05 and XIEG12 enhanced plant tolerance to salt stress significantly (p < 0.05) through the promotion of shoot, root development, and reduced the activities of antioxidant enzymes (SOD, POD, and CAT), compared with uninoculated controls in vivo. Furthermore, inoculation of strain XIEG57 was capable of reducing cotton disease incidence (DI) symptoms caused by V. dahliae at all tested salt concentrations. The GC-MS analysis showed that many compounds are known to have antimicrobial and antifungal activity. Our findings provide valuable information for applying strains XIEG05 and XIEG12 as bioinoculant fertilizers and biological control agent of cotton under saline soil conditions. [ABSTRACT FROM AUTHOR]

Culture-independent techniques revealed that I Actinobacteria i dominated in nodule environment of Tunisia, with I Frankia i spp. most frequently being detected (Ghodhbane-Gtari et al.). Keywords: Actinobacteria; diversity; biosynthesis gene clusters; secondary metabolites; bioactive compounds EN Actinobacteria diversity biosynthesis gene clusters secondary metabolites bioactive compounds 1 3 3 05/09/22 20220505 NES 220505 I Actinobacteria i are the most closely related prokaryotic microorganisms of significance to humans. The endophytic I Streptomyces i strain YINM00001, has shown to be strong antimicrobial activity and multiple antibiotic resistances, was predicted as a promising candidate to discover valuable secondary metabolites by genome mining, and proven by using OSMAC approach (Liu et al.). [Extracted from the article]