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A novel cellulase-producing actinomycete strain Gxj-6T, isolated from soil in the cold region (Heihe city, Heilongjiang province, the northernmost part of China), subjected to a taxonomic study using a polyphasic approach. In the neighbour-joining phylogenetic tree based on 16S rRNA gene sequences, strain Gxj-6T fell within the clade comprising the type strains of species of the genus Microbispora. 16S rRNA gene sequence similarity studies exhibited that species Gxj-6T was most closely related to Microbispora bryophytorum NEAU-TX2-2T (99.45%), Microbispora fusca NEAU-HEGS1-5T (99.41%), Microbispora camponoti 2C-HV3T (99.31%) and Microbispora rosea subsp. rosea JCM 3006T (98.68%). Organism Gxj-6T contained MK-9(H2) as the predominant ubiquinone and C18:0 10-methyl as the major fatty acid. The major polar lipids of culture Gxj-6T were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannoside, three unidentified phospholipids, two unidentified glycolipids and two unidentified lipids. The DNA G+C content of strain Gxj-6T was 71.25 mol%. The morphological and chemotaxonomic properties of the strain are also consistent with those members of the genus Microbispora. Combinated with the lower DNA–DNA relatedness values, phenotypic properties, physiology and biochemistry distinctiveness with other recognized species strains, revealed that strain Gxj-6T is separated from other phylogenetically closely species of the genus Microbispora. Therefore, strain Gxj-6T is considered to represent a novel species of the genus Microbispora, for which the name Microbispora cellulosiformans sp. nov. is proposed. The type strain is Gxj-6T (= CGMCC 4.7605T = DSM 109712T).

Strain CR1-09T, an actinomycete isolated from the root of Catharanthus roseus, was taxonomically studied based upon polyphasic approaches. The isolate formed a pair of ovular to circular, smooth-surfaced spores on short sporophores alternately branched from aerial mycelia. It contained meso-diaminopimelic acid in cell wall peptidoglycans. The major menaquinones were MK-9 (H4) and MK-9 (H2). The predominant cellular fatty acids were iso-C16 : 0 and C16 : 0. The polar lipids profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, hydroxyl phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides, and unidentified ninhydrin positive phosphoglycolipids. Strain CR1-09T showed the highest 16S rRNA gene sequence similarity with Microbispora tritici DSM 104650T (99.5 %). Based on the polyphasic approach, DNA–DNA relatedness and average nucleotide identity (ANI), the strain is considered to represent a novel species of the genus Microbispora , for which the name Microbispora catharanthi is proposed. The type strain is strain CR1-09T (=JCM 30045T=TISTR 2273T).

A novel actinomycete, designated strain NEAU-HEGS1-5T, was isolated from the ear of wheat (Triticum aestivum L.) and characterized using a polyphasic approach. The morphological and chemotaxonomic characteristics of the strain coincided with those of members of the genus Microbispora . The results of 16S rRNA gene sequence analysis showed that the isolate was most closely related to Microbispora bryophytorum NEAU-TX2-2T (99.3 %), Microbispora camponoti 2C-HV3T (99.2 %), Microbispora amethystogenes JCM 3021T (99.1 %) and Microbispora rosea subsp. rosea JCM 3006T (98.5 %). However, two tree-making algorithms supported the position that strain NEAU-HEGS1-5T formed a distinct clade with M. bryophytorum NEAU-TX2-2T, M. camponoti 2C-HV3T and M. rosea subsp . rosea JCM 3006T. Furthermore, multilocus sequence analysis based on the 16S-gyr B-rpo B genes and a combination of DNA–DNA hybridization results and some physiological and biochemical properties demonstrated that the strain could be distinguished from its closest relatives. Therefore, it is proposed that strain NEAU-HEGS1-5T should be classified as representative of a novel species of the genus Microbispora , for which the name Microbispora fusca sp. nov. is proposed. The type strain is NEAU-HEGS1-5T (=CCTCC AA 2019030T=DSM 104648T).

Nine new chromone analogs (1–9) were isolated from the soil actinomycete Microbispora sp. TBRC6027. The chemical structures were determined based upon NMR spectroscopic methods. These compounds were evaluated in vitro by using P19-derived neurons for neuroprotective activity against oxidative stress induced by serum deprivation and showed % viability of neurons at the concentration of 1 ng/mL varied from 43.51% to 52.99% without significant neurotoxicity for P19-derived neurons at the same concentration. Moreover, all tested compounds were inactive for antibacterial activity against both Gram-positive and Gram-negative bacteria and for cytotoxicity against MCF-7 (human breast cancer) and Vero cells at maximum tested concentration 50 μg/mL. However, compounds 4, 6, and 7 displayed weak cytotoxicity against NCI-H187 (human small-cell lung cancer) cells with IC50 in a range of 87.99–91.57 μM.

A novel actinomycete, designated strain NEAU-HRGS1-13T, was isolated from a root of wheat (Triticum aestivum L.) and characterised using a polyphasic approach. Morphological and chemotaxonomic characteristics were consistent with those of members of the genus Microbispora. The major menaquinones were identified as MK-9(H2) and MK-9(H4) and the whole cell hydrolysates found to contain meso-diaminopimelic acid and madurose. The phospholipid profile was found to consist of diphosphatidylglycerol, a ninhydrin-positive glycophospholipid, phosphatidylinositol mannosides, phosphatidylmonomethylethanolamine, an unidentified glycolipid and an unidentified lipid. The major fatty acids were identified as iso-C16:0, C16:0, 10-methyl C17:0, C18:0 and C17:0. The 16S rRNA gene sequence analysis showed that the isolate is closely related to Microbispora triticiradicis NEAU-HRDPA2-9T (99.4%), Microbispora bryophytorum NEAU-TX2-2T (99.0%), Microbispora camponoti 2C-HV3T (98.8%), Microbispora hainanensis DSM 45428T (98.8%), Microbispora amethystogenes JCM 3021T (98.6%), Microbispora siamensis NBRC 104113T (98.5%), Microbispora corallina JCM 10267T (98.3%) and Microbispora rosea subsp. rosea JCM 3006T (98.2%). However, DNA–DNA relatedness and cultural, physiological and biochemical data showed that strain NEAU-HRGS1-13T can be distinguished from its close relatives. Therefore, it is concluded that strain NEAU-HRGS1-13T represents a novel species of the genus Microbispora, for which the name Microbispora tritici sp. nov. is proposed. The type stain is NEAU-HRGS1-13T (= CGMCC 4.7402T = DSM 104650T).

An endophytic actinomycete, designated strain RL4-1ST, was isolated from surface-sterilized leaves of rice plant (Oryza sativa L.) collected from Buri Rum province, Thailand. Its taxonomic status was determined using a polyphasic approach. Phylogenetic analysis based on the 16S rRNA gene sequences showed that the strain RL4-1ST belongs to the genus Microbispora and is most closely related to Microbispora rosea subsp. rosea ATCC 12950T (98.5%). The strain forms pairs of spores on short sporophores borne on the aerial mycelium. Polar lipid profile of strain RL4-1ST is diphosphatidylglycerol, hydroxy-phosphatidylethanolamine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides, ninhydrin-positive glycophospholipid, two unidentified phospholipids, an unidentified aminolipid, and an unidentified glycolipid. MK-9(H4), MK-9(H2), and MK-9 are major menaquinones of this organism. The predominant cellular fatty acids are iso-C16:0, C17:0 and C16:0. Strain RL4-1ST contains meso-diaminopimelic acid, glucose, madurose and ribose in whole-cell hydrolysates. The draft genome of strain RL4-1ST consists of 7.46 Mbp and has a G + C content 71.2 mol%. Digital DNA–DNA hybridization and average nucleotide identity values between the genome sequence of strain RL4-1ST with Microbispora rosea subsp. rosea ATCC 12950T are 26.0% and 80.7%, respectively. Based on data of genotypic, phenotypic, phylogenetic and chemotaxonomic analysis, strain RL4-1ST represents a novel species of the genus Microbispora, for which the name Microbispora oryzae sp. nov. is proposed. The type strain is RL4-1ST (= TBRC 14817T = NBRC 115115T).

Setiawati S, Nuryastuti T, Sholikhak EN, Lisdiyanti P, Pratiwi SUT, Sulistiyanti TR, Ratnakomala S, Jumina, Mustofa. 2021. The potency of actinomycetes extracts isolated from Pramuka Island, Jakarta, Indonesia as antimicrobial agents. Biodiversitas 22: 1104-1111. Actinomycetes are one of the Gram-positive bacteria which are widely distributed and produce many secondary metabolites including those known as antibiotics, antifungals, anticancer, and antimalarials agents. The secondary metabolites of actinomycetes are abundant, which include many active compounds that have been identified because of the large diversity in the actinomycetes phylum. This study aimed to identify and screen collected by Indonesian Culture Collection (InaCC) from Bojong Gede and Pramuka Island, Jakarta, Indonesia as antibacterial and antifungal agents. Primary screening was done on 16 actinomycetes isolates by well-agar diffusion method. Antimicrobial activity was tested by using micro broth dilution methods to determine minimum inhibitory concentration (MIC). Molecular identification into level genera and species was determined by 16S rRNA gene sequencing. Out of 16 actinomycetes isolates used, 4 isolates have activity against Candida albicans ATCC 10231, Staphylococcus aureus ATCC 6538, Bacillus subtilis BTCC B-612, and Escherichia coli BTCC B-614, specifically InaCC A758, InaCC A759, InaCC A760 and InaCC A765 isolates. InaCC A758 have highest antimicrobial activity against mentioned microbial with MIC value at 50 μg/mL, 6.25 μg/mL, 31.25 μg/mL and 3.125 μg/mL, respectively. Three genera were found from the samples: i.e. Streptomyces (80%), Microbispora (13%) and Nocardia (6%). Based on 16S rRNA gene identification, the active isolates of actinomycetes InaCC A758, InaCC A759, InaCC A760 and InaCC A765 were similar to Streptomyces badius, Streptomyces olivaceus, Streptomyces sanyensis, and Nocardia otitidiscaviarum, respectively. The secondary metabolites of actinomycetes extracts from Pramuka Island can be potentially developed as antifungal and antibacterial agents.

Actinobacteria refers to a group of Gram-positive bacteria with higher G + C DNA base content than other groups of bacteria. They belong to one of the largest bacterial genera called Actinomycetes and are known for their enormous ability to adapt to any environment (including the less explored biota such as deep sea or oceans, hydrothermal vents, etc.). It is a well-established fact that the group actinobacteria is pharmacologically very important and is highly efficient in producing secondary metabolites (such as pigments, antibiotics, toxins, alkaloids, etc.). These species have been further screened for many important and novel secondary metabolites that show a range of biological activities including anti-angiogenesis, antibacterial, anticancer, antifungal, anti-inflammatory, antimalaria, anti-parasitic, antioxidant, antitumour, antiviral, etc., to name a few. The secondary metabolites extracted from actinobacteria of the marine milieu have received extensive consideration due to their structural diversity and exceptional biological activities. Some of the actinomycetes genera such as Actinomadura, Actinoplanes, Microbispora, Micromonospora, Nocardia, Pseudonocardia and Sinomonas are known as rare species, which needs to be exploited for its applications in the field of pharmaceuticals (drug discovery). In the current chapter, an assessment is being done on the research conducted with the marine actinobacteria and the secondary metabolites produced by them of pharmaceutical importance. These secondary bioactive substances possess discrete chemical assemblies which may help in the catalysis or synthesis of new drugs. It is believed that the actinobacteria can provide promising and favourable productivity of commercially important bioactive compound with therapeutic value.

A novel actinomycete, designated strain NEAU-HRGS1-13T, was isolated from a root of wheat (Triticum aestivum L.) and characterised using a polyphasic approach. Morphological and chemotaxonomic characteristics were consistent with those of members of the genus Microbispora. The major menaquinones were identified as MK-9(H2) and MK-9(H4) and the whole cell hydrolysates found to contain meso-diaminopimelic acid and madurose. The phospholipid profile was found to consist of diphosphatidylglycerol, a ninhydrin-positive glycophospholipid, phosphatidylinositol mannosides, phosphatidylmonomethylethanolamine, an unidentified glycolipid and an unidentified lipid. The major fatty acids were identified as iso-C16:0, C16:0, 10-methyl C17:0, C18:0 and C17:0. The 16S rRNA gene sequence analysis showed that the isolate is closely related to Microbispora triticiradicis NEAU-HRDPA2-9T (99.4%), Microbispora bryophytorum NEAU-TX2-2T (99.0%), Microbispora camponoti 2C-HV3T (98.8%), Microbispora hainanensis DSM 45428T (98.8%), Microbispora amethystogenes JCM 3021T (98.6%), Microbispora siamensis NBRC 104113T (98.5%), Microbispora corallina JCM 10267T (98.3%) and Microbispora rosea subsp. rosea JCM 3006T (98.2%). However, DNA–DNA relatedness and cultural, physiological and biochemical data showed that strain NEAU-HRGS1-13T can be distinguished from its close relatives. Therefore, it is concluded that strain NEAU-HRGS1-13T represents a novel species of the genus Microbispora, for which the name Microbispora tritici sp. nov. is proposed. The type stain is NEAU-HRGS1-13T (= CGMCC 4.7402T = DSM 104650T).

The genera Microbispora and Sphaerimonospora were examined for GyrB and RecA amino-acid signatures to determine whether molecular-signature analyses support the recent establishment of the genus Sphaerimonospora. The creation of Sphaerimonospora was based mainly upon morphological differences between Microbispora and Sphaerimonospora and the clustering of the type strains of the two genera in phylogenetic trees based on a multilocus sequence analysis. The molecular-signature analyses showed that all members of Sphaerimonospora can be distinguished from all members of Microbispora at 14 amino acid positions in the GyrB protein and at four positions in the shorter RecA protein. These amino acid differences can be used as signatures to differentiate the members of these genera from each other and thus provide support for the establishment of the genus Sphaerimonospora. This is the first demonstration of the use of molecular signatures to support the establishment of a new genus in the family Streptosporangiaceae. Following the transfer of Microbispora mesophila and Microbispora thailandensis from Microbispora to Sphaerimonospora, all species in the genus Microbispora are characterised by the insertion of a small, hydrophobic amino acid after position 208 in the GyrB protein. This insertion is absent from the GyrB protein of members of the genus Sphaerimonospora.

A novel actinobacterium, designated strain NEAU-D428T, was isolated from rhizosphere soil of wheat and characterized using a polyphasic approach. Morphological and chemotaxonomic characteristics of the strain coincided with members of the genus Microbispora . The 16S rRNA gene sequence analysis showed that the isolate was most closely related to Microbispora bryophytorum NEAU-TX2-2T (99.2 %). Phylogenetic analysis based on the 16S rRNA gene sequences indicated that the strain clustered with Microbispora clausenae CLES2T (99.1 %), but formed a separate subclade in the phylogenomic tree within the genus Microbispora . The menaquinones were identified as MK-9(H4), MK-9(H2) and MK-9(H0). The phospholipid profile was found to consist of diphosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, ninhydrin-positive glycophospholipid, phosphatidylinositol and phosphatidylinositol mannoside. The major fatty acids were identified as iso-C16 : 0, C16 : 0, 10-methyl C17 : 0 and C18 : 0. Digital DNA–DNA hybridization and average nucleotide identity values between strain NEAU-D428T and M. bryophytorum NEAU-TX2-2T, Microbispora camponoti 2C-HV3T, M. clausenae CLES2T, ‘Microbispora cellulosiformans’ Gxj-6T and Microbispora fusca NEAU-HEGS1-5T were 47.6 and 92.2 %, 47.5 and 92.2 %, 55.9 and 94.0 %, 33.1 and 86.8 %, and 33.6 and 87.1 %, respectively. These results and some physiological and biochemical properties demonstrated that the strain could be distinguished from its closest relatives. Therefore, it is proposed that strain NEAU-D428T should be classified as representative of a novel species of the genus Microbispora , for which the name Microbispora sitophila sp. nov. is proposed. The type strain is NEAU-D428T (=CGMCC 4.7523T=DSM 109822T).

Nature is the major reservoir of biologically active molecules. The urgent need of finding novel molecules for pharmaceutical application is prompting the research of underexplored environments, such as marine ecosystems. Here, we investigated cultivable actinobacteria associated with the macroalgae Laminaria ochroleuca and assessed their potential to produce compounds with antimicrobial or anticancer activities. A specimen of L. ochroleuca was collected in a rocky shore in northern Portugal, and fragments of tissues from different parts of the macroalgae (holdfast, stipe, and blades) were surface sterilized and plated in three culture media selective for actinobacteria. A total of 90 actinobacterial strains were isolated, most of which affiliated with the genus Streptomyces. Isolates associated with the genera Isoptericola, Rhodococcus, Nonomuraeae, Nocardiopsis, Microbispora, and Microbacterium were also obtained. Organic extracts from the isolates were tested for their antimicrobial activity using the agar-based disk diffusion method, followed by determination of minimum inhibitory concentration (MIC) values. Forty-five isolates inhibited the growth of Candida albicans and/or Staphylococcus aureus, with MIC values ranging from

Description of Microbispora bryophytorum Gsoil 554 Cells are Gram-stain-positive, non-flagellated, and mycelium-forming. Colonies are filamentous, umbonate, and brown colored after 2 days of incubation on R2 A at 30° C. Nitrate is reduced and esculin is hydrolyzed. The strain shows positive reactions for enzyme activities of β -galactosidase and oxidase, whereas the strain shows negative reactions for enzyme activities of gelatinase, urease, and arginine dihydrolase. Indole is not produced and glucose is not fermented. The strain utilizes D-glucose, L-arabinose, N -acetyl-glucosamine, and potassium gluconate, whereas the strain does not utilize D-mannose, D-mannitol, D-maltose, capric acid, adipic acid, malic acid, trisodium citrate, and phenyl acetic acid. Strain Gsoil 554 (= NIBRBAC000500986) was isolated from a soil sample, Pocheon, Gyeonggi Province, Korea., Published as part of Kim, Mi-Sun, Jeong, Seong-Hwa, Kang, Joo-Won, Kim, Seung-Bum, Cho, Jang-Cheon, Cha, Chang-Jun, Im, Wan-Taek, Bae, Jin-Woo, Lee, Soon-Dong, Kim, Won-Yong, Kim, Myung-Kyum & Seong, Chi-Nam, 2019, Unrecorded prokaryotic species belonging to the class Actinobacteria in Korea, pp. 97-108 in Journal of Species Research 8 (1) on page 107, DOI: 10.12651/JSR.2019.8.1.097, http://zenodo.org/record/8120476

Three undescribed abyssomicin derivatives, including microbimisin, abyssomicins Z1, and Z2, were isolated from the soil actinomycete Microbispora rhizosphaerae sp. nov. TBRC6028. Chemical structures were determined by NMR spectroscopic data (1H, 13C, COSY, HSQC, HMBC, and NOESY spectra) and the absolute configurations were verified by single-crystal X-ray diffraction analyses together with the ECD spectral data. Microbimisin and abyssomicin Z1 exhibited weak antibacterial activity against Bacillus cereus with MIC values of 25.0 and 50.0 μg/mL without cytotoxicity against MCF-7 and Vero cells at the concentration of 50 μg/mL.

Glycopeptides and several lantibiotics are lipid II-targeting antibiotics produced by actinomycetes. To protect themselves from their own product, antibiotic producers developed self-resistance mechanisms. Inspection of different producer strains revealed that their resistance is not only based on a single determinant but on the synergistic action of different factors. Glycopeptide producers possess different ways to synthesize a modified peptidoglycan to prevent the binding of the glycopeptide antibiotic. One possible modification is the synthesis of peptidoglycan precursors terminating with a D-alanyl-D-lactate (D-Ala-D-Lac) rather than with a D-alanyl-D-alanine (D-Ala-D-Ala) resulting in a 1000-fold decreased binding affinity of the glycopeptide to its target. The reprogramming of the peptidoglycan precursor biosynthesis is based on the action of VanHAX or paralogous enzymes as it was shown for Amycolatopsis balhimycina. A second peptidoglycan modification resulting in glycopeptide resistance was investigated in the glycopeptide A40926 producer Nonomuraea ATCC 39727. Nonomuraea eliminates the glycopeptide target by synthesizing a peptidoglycan with 3-3 cross-linked peptide stems. The carboxypeptidase VanYn provides tetrapeptides which serve as substrates for the L,D-transpeptidase catalyzing the formation of 3-3 cross-links. The occurrence of 3-3 cross-linked dimers is also an important feature of the lantibiotic NAI-107 producer Microbispora ATCC PTA-5024. Moreover, the D-Ala in the fourth position in the acceptor peptide of muropeptides is exchanged to glycine or serine in Microbispora, a side reaction of the L,D-transpeptidase. Together with the lipoprotein MlbQ, the ABC transporter MlbYZ and the transmembrane protein MlbJ it might contribute to the self-resistance in Microbispora ATCC PTA-5024.

Proteomics based on 2D-Difference In Gel Electrophoresis (2D-DIGE) coupled with mass spectrometry (MS) procedures can be considered a “gold standard” to determine quantitatively and comparatively protein abundances in cell extracts from different biological sources/conditions according to a gel-based approach. In particular, 2D-DIGE is used for protein specie separation, detection, and relative quantification, whenever tandem MS is used to obtain peptide sequence information that is managed according to bioinformatic procedures to identify the differentially represented protein species. The proteomic results consist of a dynamic portray of over- and down-represented protein species that, with the integration of gene ontology resources, allow obtaining a comprehensive understanding of the complex network of molecular signaling, regulatory circuits, and biochemical reactions occurring in cellular contexts. For this reason, proteomics has been widely used for studying molecular physiology of Gram-positive bacterial strains producing bioactive metabolites and belonging to actinomycete family. This highlighted the complex relationships linking overall regulatory processes and metabolic pathways to the biosynthesis of interesting bioactive molecules. In this chapter, we provide a detailed description of the procedures adopted to perform a differential proteomic analysis of the actinomycete Microbispora ATCC-PTA-5024, producing the promising NAI-107 lantibiotic. Although each experimental proteomic procedure has to be optimized to face the specific molecular characteristics of the organism under investigation, the protocols here described have also been used with minor modifications for proteomic studies on other bacterial strains, including the actinomycetes Streptomyces coelicolor, S. ambofaciens, Amycolatopsis balhimycina, and the Gram-negative proteobacteria Klebsiella oxytoca and Pseudoalteromonas haloplanktis.

Endophytic actinomycetes from medicinal plants produce a wide diversity of secondary metabolites (SM). However, to date, the knowledge about endophytes from Brazil remains scarce. Thus, we analyzed the antimicrobial potential of 10 actinomycetes isolated from the medicinal plant Vochysia divergens located in the Pantanal sul-mato-grossense, an unexplored wetland in Brazil. Strains were classified as belonging to the Aeromicrobium, Actinomadura, Microbacterium, Microbispora, Micrococcus, Sphaerisporangium, Streptomyces, and Williamsia genera, through morphological and 16S rRNA phylogenetic analyzes. A susceptibility analysis demonstrated that the strains were largely resistant to the antibiotics oxacillin and nalidixic acid. Additionally, different culture media (SG and R5A), and temperatures (28 and 36°C) were evaluated to select the best culture conditions to produce the active SM. All conditions were analyzed for active metabolites, and the best antibacterial activity was observed from metabolites produced with SG medium at 36°C. The LGMB491 (close related to Aeromicrobium ponti) extract showed the highest activity against methicillin-resistant Staphylococcus aureus (MRSA), with a MIC of 0.04 mg/mL, and it was selected for SM identification. Strain LGMB491 produced 1-acetyl-β-carboline (1), indole-3-carbaldehyde (2), 3-(hydroxyacetyl)-indole (4), brevianamide F (5), and cyclo-(L-Pro-L-Phe) (6) as major compounds with antibacterial activity. In this study, we add to the knowledge about the endophytic community from the medicinal plant V. divergens and report the isolation of rare actinomycetes that produce highly active metabolites.

The development of communities of three important composting players including actinobacteria, fungi and clostridia was explored during the composting of wheat straw for mushroom production. The results revealed the presence of highly diversified actinobacteria and fungal communities during the composting process. The diversity of the fungal community, however, sharply decreased in the mature compost. Furthermore, an apparent succession of both actinobacteria and fungi with intensive changes in the composition of communities was demonstrated during composting. Notably, cellulolytic actinomycetal and fungal genera represented by Thermopolyspora, Microbispora and Humicola were highly enriched in the mature compost. Analysis of the key cellulolytic genes revealed their prevalence at different composting stages including several novel glycoside hydrolase family 48 exocellulase lineages. The community of cellulolytic microbiota also changed substantially over time. The prevalence of the diversified cellulolytic microorganisms holds the great potential of mining novel lignocellulose decomposing enzymes from this specific ecosystem.

Higher order taxonomic assignments (family level and above) in the phylum Actinobacteria are currently based only on 16S-rRNA gene sequence analyses. Additional molecular markers need to be identified to increase the number of reference points for defining actinobacterial families and other higher taxa. Furthermore, since most novel actinobacterial taxa are defined at the level of species and genera, it is necessary to define molecular signatures at the genus level to enhance the robustness of genus descriptions. The current use of chemotaxonomic markers to define genera could be improved by the identification of genus-specific molecular signatures. In this study, GyrB amino acid sequences for members of the family Streptosporangiaceae were analysed for molecular signatures. Phylogenetic analyses showed that the gyrB gene tree supported the composition of the currently recognised genera in this family. The catalytically important amino acids were identified in the GyrB sequences, as were the GHKL superfamily motifs. Examination of GyrB protein sequence alignments revealed that there are genus-specific sequences for most of the multi-species genera and genus-defining amino acid insertions for the genera Herbidospora and Microbispora. Furthermore, there are GyrB signature amino acids which distinguish the family Streptosporangiaceae from the family Nocardiopsaceae.

Peptidoglycan (PG) is a bacteria specific cell surface layer that ensures the bacterial shape and integrity. The two actinomycetes Amycolatopsis balhimycina and Microbispora sp. PTA-5024 are producers of PG targeting antibiotics. To prevent the binding of their secreted product to their own PG, they developed specific self-resistance mechanisms. Modifications of PG, which are applied by both strains, are the introduction of amide-residues at the PG precursors and the alternative crosslinks within the nascent PG. The PG modifications found in Microbispora sp. PTA-5024 seemed to be an intrinsic characteristic of the genus Microbispora, rather than a specific mechanism of NAI-107 resistance. In contrast, the modifications in A. balhimycina represent an alternative way to avoid suicide specific for glycopeptide producers. The different PG modifications reflect the fact that antibiotic producing organisms contain not only one but multiple mechanisms to ensure protection against biologically active molecules produced by themselves.

The rapid expansion of mandarin (Citrus reticulata L.) production areas with high agrochemical input in the highland areas of northern Thailand has resulted in negative effects in terms of production, environment, soil quality, and public health. The use of microorganisms as plant growth promoters is an alternative method to reduce agrochemical input. Thus, we studied the diversity of endophytic actinomycetes in mandarin and their potential as plant growth promoters. A total of 252 endophytic actinomycete isolates were recovered from mandarin. Based on spore chain morphology, cell wall type, and 16S rRNA gene sequence, the isolates were classified into six genera: Streptomyces, Nocardia, Nocardiopsis, Spirillospora, Microbispora and Micromonospora. The most frequent isolates recovered were members of Streptomyces (85.3%). Selected isolates (64 isolates) from these genera were evaluated for their indole-3-acetic acid (IAA) production potential in a medium with 2 mg mL−1 tryptophan, and all the sel...

Description of Microbispora rosea subsp. rosea UKS-23 Cells are Gram-staining-negative, non-flagellated and rod­shaped. Colonies are circular, raised, entire and yellow-colored after 2 day on R2A at 25℃. Positive reaction is obtained for esculin hydrolysis in API 20NE, and negative reactions are obtained for nitrate reduction, indole production, glucose fermentation, arginine dihydrolase, urease, gelatinase and β-galactosidase. D-glucose, L­arabinose, D­mannose, D­mannitol, N ­acetyl­glucosamine, D­maltose, potassium gluconate, adipic acid and malic acid are utilized. Does not utilize capric acid, trisodium citrate and phenylacetic acid. Strain UKS­23 (= NIBRBA0000113886) was isolated from a wetland sample, Ungok­ri, Gochang, Korea., Published as part of Choi, Jung-Hye, Cha, Ju-Hee, Bae, Jin-Woo, Cho, Jang-Cheon, Chun, Jongsik, Im, Wan-Taek, Jahng, Kwang Yeop, Jeon, Che Ok, Joh, Kiseong, Kim, Seung Bum, Seong, Chi Nam, Yoon, Jung-Hoon & Cha, Chang-Jun, 2016, Report on 31 unrecorded bacterial species in Korea that belong to the phylum Actinobacteria, pp. 1-13 in Journal of Species Research 5 (1) on page 11, DOI: 10.12651/JSR.2016.5.1.001, http://zenodo.org/record/8120360

Rhizospheric and endophytic microbial population plays a key role in sustaining plant production under either nutrient-limited or sufficient conditions. Endophytic microorganisms that are internalized in plants offer a competitive advantage over rhizospheric microorganisms in the growing environments. Among various endophytic microorganisms, the Gram-positive actinobacteria have gained considerable interests due to their secondary metabolites production. Besides Frankia, a large number of cultivable actinobacteria such as Streptomyces spp., Nocardiopsis, Actinoplanes spp., Micromonospora, Microbispora, and Streptosporangium show endophytic lifestyles in diverse plant species. Recent advances in molecular tools show the existence of “yet to be uncultured but viable organisms” within this group. The colonization of endophytic actinobacteria depends on plant species, soil types, and varied environmental factors. Their metabolic capabilities even make them an important source of plant hormones, antibiotics, and other bioactive molecules that are used in agriculture and pharmaceutical industries. In the legume plants, the nodule inhabiting actinobacteria such as Micromonospora, Streptomyces sp., Nocardia alba, Nonomuraea rubra, and Actinomadura glauciflava have probiotic effects with Rhizobium. In the present chapter, the potential role of the plant-associated actinobacteria in sustainable agriculture and their endophytic lifestyles has been reviewed.

The taxonomic position of actinomycete strain NN276(T), isolated from cave soil, was studied using the polyphasic taxonomic approach. A phylogenetic tree based on 16S ribosomal RNA (rRNA) gene sequences showed that the isolate formed a distinct evolutionary linage with the genus Microbispora, with M. mesophila JCM 3151(T) as its closest phylogenetic neighbor (97.9% similarity). The organism contained meso-diaminopimelic acid and the N-acetyl type of peptidoglycan. Madurose was detected in the whole-cell hydrolasate. The predominant menaquinones were MK-9(H(4)), MK-9(H(2)) and MK-9. Mycolic acids were not detected. Major phospholipids were diphosphatidylglycerol, hydroxy-phosphatidylethanolamine, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside. The major cellular fatty acid was iso-C(16: 0) and G+C content 70 mol%. DNA-DNA hybridization demonstrated that the isolate was distinct from M. mesophila JCM 3151(T). On the basis of phenotypic and genotypic data, it is proposed that strain NN276(T) represents a novel species of the genus Microbispora, hence the name Microbispora thailandensis sp. nov. The type strain is strain NN276(T) (=BCC 41490(T)=NRRL B-24806(T)=NBRC 107569(T)).

Phenol treatment was applied for isolation of rare Actinomycetes using 25 soil samples collected from Pulau Seribu, Tanjung Redep, Manokwari, and Halmahera. The samples were air-dried and suspended in 1.5 % (w/v) phenol solution at 30 oC for 30 minutes, and subsequently cultured on plates of humic acid-vitamin agar (HVA) medium supplemented with cycloheximide (50 μg/mL) and nystatin (50 μg/mL). A total of 61 isolates were obtained and the most dominant isolates were not Streptomyces (only 24.6%), whereas other genera such as Micromonospora , Actinomadura , Microbispora and Polymorphospora were isolated with ratios of 49.2%, 13.1%, 9.8%, and 3.3%, respectively.

Clarifying the identity and enzymatic activities of microorganisms associated with the decomposition of organic materials is expected to contribute to the evaluation and improvement of composting processes. In this study, we examined the cellulolytic and hemicellulolytic abilities of bacteria isolated from sawdust compost (SDC) and coffee residue compost (CRC). Cellulolytic bacteria were isolated using Dubos mineral salt agar containing azurine cross-linked (AZCL) HE-cellulose. Bacterial identification was performed based on the sequence analysis of 16S rRNA genes, and cellulase, xylanase, β-glucanase, mannanase, and protease activities were characterized using insoluble AZCL-linked substrates. Eleven isolates were obtained from SDC and 10 isolates from CRC. DNA analysis indicated that the isolates from SDC and CRC belonged to the genera Streptomyces, Microbispora, and Paenibacillus, and the genera Streptomyces, Microbispora, and Cohnella, respectively. Microbispora was the most dominant genus in both compost types. All isolates, with the exception of two isolates lacking mannanase activity, showed cellulase, xylanase, β-glucanase, and mannanase activities. Based on enzyme activities expressed as the ratio of hydrolysis zone diameter to colony diameter, it was suggested that the species of Microbispora (SDCB8, SDCB9) and Paenibacillus (SDCB10, SDCB11) in SDC and Microbispora (CRCB2, CRCB6) and Cohnella (CRCB9, CRCB10) in CRC contribute to efficient cellulolytic and hemicellulolytic processes during composting.

Endophytic actinobacterial diversity in the native herbaceous plant species of Korea was analyzed using a culture-based approach. Sixty one actinobacterial strains were isolated, and assigned to 15 genera based on 16S rRNA gene analysis. The members of the genus Streptomyces comprised 45.9% of the total isolates, followed by Micromonospora (18.8%), Rhodococcus (6.6%), Microbispora (4.9%), and Micrococcus (4.9%). Other minor constituents included members of Microbacterium, Streptacidiphilus, Arthrobacter, Dietzia, Kitasatospora, Herbiconiux, Mycobacterium, Nocardia, Rathayibacter, and Tsukamurella. Among the isolates, 65.6% exhibited at least one hydrolytic enzyme activity out of four, and 45.9% exhibited antagonistic activity against at least one fungal pathogen out of five, thus demonstrating that endophytic actinobacteria can be an important source of bioactive compounds. Notably, most strains of Streptomyces proved active for both enzymatic and antagonistic activities.

The inside of Pinus thunbergii could be a reliable screening source for a useful agent in controlling plant disease. Isolation of endophytic actinomycetes from P. thunbergii and their potential as biocontrol agents against the plant pathogen Cylindrocladium sp. were investigated. Two endophytic actinomycetes, Streptomyces sp. and Microbispora sp., were isolated from surface-sterilised root tissues of P. thunbergii seedlings. The recovery test of these two endophytic actinomycetes from pine seedling showed that Streptomyces sp. was isolated from only roots, but Microbispora sp. was isolated from both roots and leaves. Thus, Microbispora sp. is able to move to leaves from roots. Moreover, we evaluated the potential of both strains as biocontrol agents against Cylindrocladium sp. Two weeks after inoculation of Cylindrocladium sp. alone, pine seedlings showed a 50% mortality rate. Co-inoculation of Cylindrocladium sp. and Microbispora sp. did not affect seedling mortality rate. However, inoculation with both ...

Lantibiotics 97518 and NAI-107, produced by the related genera Planomonospora and Microbispora respectively, are members of a family of nisin-related compounds. They represent promising compounds to treat infections caused by multiresistant Gram-positive pathogens. Despite their similar structure and a similar antibacterial spectrum, the two lantibiotics exhibit significant differences in their potency. To gain an insight into the structure-activity relationships, their conformational properties in solution are determined by NMR. After carrying out an NOE analysis of 2D (1)H NMR spectra, high-resolution 3D structures are determined using molecular dynamics simulations.

Lantibiotics are ribosomally synthesized, posttranslationally modified peptide antibiotics. Microbisporicin is a potent lantibiotic produced by the actinomycete Microbispora corallina and contains unique chlorinated tryptophan and dihydroxyproline residues. The biosynthetic gene cluster for microbisporicin encodes several putative regulatory proteins, including, uniquely, an extracytoplasmic function (ECF) σ factor, σ MibX , a likely cognate anti-σ factor, MibW, and a potential helix-turn-helix DNA binding protein, MibR. Here we examine the roles of these proteins in regulating microbisporicin biosynthesis. S1 nuclease protection assays were used to determine transcriptional start sites in the microbisporicin gene cluster and confirmed the presence of the likely ECF sigma factor −10 and −35 sequences in five out of six promoters. In contrast, the promoter of mibA , encoding the microbisporicin prepropeptide, has a typical Streptomyces vegetative sigma factor consensus sequence. The ECF sigma factor σ MibX was shown to interact with the putative anti-sigma factor MibW in Escherichia coli using bacterial two-hybrid analysis. σ MibX autoregulates its own expression but does not directly regulate expression of mibA . On the basis of quantitative reverse transcriptase PCR (qRT-PCR) data, we propose a model for the biosynthesis of microbisporicin in which MibR functions as an essential master regulator and the ECF sigma factor/anti-sigma factor pair, σ MibX /MibW, induces feed-forward biosynthesis of microbisporicin and producer immunity.

Problems on the resistance of soil actinomycetes to various environmental factors (pH, salinity, temperature, and moisture) are discussed. Actinomycetes as a special group of prokaryotes were revealed to have a greater range of tolerance to these factors than was thought earlier. The regularities of the distribution of extremophilic and extremotolerant actinomycetes developing in unusual for mycelial bacteria conditions, their structural-functional characteristics, and their taxonomic composition were determined. The predominance of acidophilic representatives of the Micromonospora genus in acid soils (typical peat, soddy-podzolic, and taiga podzol) and the haloalkaliphilic Streptomyces pluricilirescens and S. prunicolor species in desert saline soils are shown. The specific features of the actinomycete complexes on thermal fields of the weakly developed stratified volcanic soils are described. In these complexes, the thermophilic forms were represented only by species of the Micromonospora genus; and the mesophilic forms, by Microbispora species. In the periodically heated desert soils, among the thermophilic actinomycetes, representatives of rare Actinomadura, Saccharopolyspora and Streptosporangium genera along with Streptomyces species were indicated. The mechanisms of the resistance of the actinomycetes to the extreme environmental conditions are discussed.

Marine waste is a highly renewable resource for the recovery of several value added metabolites with prospective industrial applications. This study describes the production of enzymes on marine waste and their subsequent use for the extraction of antioxidants from marine waste. Microbispora sp. and Bacillus sp. were grown on colloidal chitin and marine waste for the production of chitinase and protease. Microbispora sp. could produce 10.2 U ml−1 chitinase, whereas Bacillus sp. could produce 38 U ml−1 chitinase and 3.39 U ml−1 protease. The production of antioxidants was optimized using statistical designs and 6.6 units of 35 kDa chitinase from Microbispora sp., 16 units of 25 kDa chitinase from Bacillus sp., 2.3 units of protease, 1.5% marine waste and 36 h incubation gave maximum antioxidant activity. Nearly 5.0 mg of compound with antioxidant activity could be recovered per gram of marine waste. This compound was purified by HPLC and characterized by TLC, FT-IR and proton-NMR as N,N′-diacetylchitobiose. It exhibited 53% superoxide radical scavenging activity, 57% hydroxyl radical scavenging activity and 28% lipid peroxidation inhibition activity. Scale up of the extraction of antioxidant from marine waste and its pharmacological studies can extend its use in medicine.

The results of the research of rare species of actinomycetes in some soils of Azerbaijan were studied. On the selective media the representatives of Streptomyces, Streptosporangium, Micromonospora, Actinomadura, Microbispora, Saccharopolyspora and Saccharomonospora were revealed. Species of Streptomyces and Micromonospora dominate in mountain-wood ecosystems (60 %.). It was established that among streptomyces species of Cinereus section of Violaceus series; Helvolo-Flavus sections of Helvolus series, Roseus sections of Fuscus series; Azureus sections of Coerulescens series. It was established that amount of termotolerant actinomycetes in the investigated desert soils of Azerbaijan depends on the incubation temperature. The species of Streptomyces, Micromonospora, Saccharopolyspora and Actinomadura genera were isolated from desert soils of Azerbaijan.

It has been found that the number of thermotolerant actinomycetes in strongly heated soils of deserts and volcanic regions is comparable to or exceeds the number of mesophilic actinomycetes. Among the latter group, streptomyces usually predominate; among thermotolerant actinomycetes, representatives of the Micromonospora, Streptosporangium, Actinomadura, Saccharopolyspora, Microtetraspora, and Microbispora genera are identified. Thermotolerant actinomycetes display the full cycle of their development in these soils. The method of fluorescent in situ hybridization has made it possible to determine that mycelial forms predominate among the metabolically active representatives of Actinobacteria; their portion increases with the rise in the temperature of soil incubation.

The actinomycetal community structures in marine and freshwater environments (the Pacific Ocean, East China Sea, Tokyo Bay, and Arakawa River) were investigated by a culture-independent molecular method to clarify spatial and seasonal distributions. Deoxyribonucleic acid (DNA) was extracted from environmental water samples, and a community analysis was carried out on polymerase chain reaction-amplified 16S ribosomal DNA. The amplified DNA fragments were analyzed by denaturing gradient gel electrophoresis (DGGE) and nonmetric multidimensional scaling analysis, followed by sequencing analysis. The actinomycetal community structures were different at each station in the Pacific Ocean, the East China Sea, Tokyo Bay, and Arakawa River, and different populations predominated in each area. There were vertical variations in actinomycetal communities in the Pacific Ocean and East China Sea between the surface and 100-m depth, but communities were similar from 200- to 1,000-m depths. There were also distinct seasonal variations in communities in Tokyo Bay. Phylogenetic analysis of DNA fragments recovered from DGGE bands revealed that most of the predominant actinomycetal strains were uncultured and were quite different from well known culturable strains, such as the Streptomyces, Micromonospora, Microbispora, Salinispora, and Actinoplanes groups. These results suggest that the marine environment is an attractive target for discovering new actinomycetal populations producing bioactive compounds and that sampling depth and season are important considerations for isolating various populations effectively.