Innovative Eco-Friendly Microwave-Assisted Rapid Biosynthesis of Ag/AgCl-NPs Coated with Algae Bloom Extract as Multi-Functional Biomaterials with Non-Toxic Effects on Normal Human Cells.

Harmful algal blooms impact human welfare and are a global concern. Sargassum spp., a type of algae or seaweed that can potentially bloom in certain regions of the sea around Thailand, exhibits a noteworthy electron capacity as the sole reducing and stabilizing agent, which suggests its potential for mediating nanoparticle composites. This study proposes an eco-friendly microwave-assisted biosynthesis (MAS) method to fabricate silver nanoparticles coated with Sargassum aqueous extract (Ag/AgCl-NPs-ME). Ag/AgCl-NPs-ME were successfully synthesized in 1 min using a 20 mM AgNO3 solution without additional hazardous chemicals. UV-visible spectroscopy confirmed their formation through a surface plasmon resonance band at 400-500 nm. XRD and FTIR analyses verified their crystalline nature and involvement of organic molecules. TEM and SEM characterization showed well-dispersed Ag/AgCl-NPs-ME with an average size of 36.43 nm. The EDS results confirmed the presence of metallic Ag+ and Cl- ions. Ag/AgCl-NPs-ME exhibited significant antioxidant activity against free radicals (DPPH, ABTS, and FRAP), suggesting their effectiveness. They also inhibited enzymes (tyrosinase and ACE) linked to diseases, indicating therapeutic potential. Importantly, the Ag/AgCl-NPs-ME displayed remarkable cytotoxicity against cancer cells (A375, A549, and Caco-2) while remaining non-toxic to normal cells. DNA ladder and TUNEL assays confirmed the activation of apoptosis mechanisms in cancer cells after a 48 h treatment. These findings highlight the versatile applications of Ag/AgCl-NPs-ME in food, cosmetics, pharmaceuticals, and nutraceuticals.

Naturally Occurring Functional Ingredient from Filamentous Thermophilic Cyanobacterium Leptolyngbya sp. KC45: Phytochemical Characterizations and Their Multiple Bioactivities.

Cyanobacteria are rich in phytochemicals, which have beneficial impacts on the prevention of many diseases. This study aimed to comprehensively characterize phytochemicals and evaluate multifunctional bioactivities in the ethanolic extract of the cyanobacterium Leptolyngbya sp. KC45. Results found that the extract mainly contained chlorophylls, carotenoids, phenolics, and flavonoids. Through LC-ESI-QTOF-MS/MS analysis, 38 phenolic compounds with promising bioactivities were discovered, and a higher diversity of flavonoids was found among the phenolic compounds identified. The extract effectively absorbed the harmful UV rays and showed high antioxidant activity on DPPH, ABTS, and PFRAP. The extract yielded high-efficiency inhibitory effects on enzymes (tyrosinase, collagenase, ACE, and α-glucosidase) related to diseases. Interestingly, the extract showed a strong cytotoxic effect on cancer cells (skin A375, lung A549, and colon Caco-2), but had a much smaller effect on normal cells, indicating a satisfactory level of safety for the extract. More importantly, the combination of the DNA ladder assay and the TUNEL assay proved the appearance of DNA fragmentation in cancer cells after a 48 h treatment with the extract, confirming the apoptosis mechanisms. Our findings suggest that cyanobacterium extract could be potentially used as a functional ingredient for various industrial applications in foods, cosmetics, pharmaceuticals, and nutraceuticals.

Bacterial Communities Associated with Crude Oil Bioremediation through Composting Approaches with Indigenous Bacterial Isolate.

In this study, we aim to investigate the efficiency of crude oil bioremediation through composting and culture-assisted composting. First, forty-eight bacteria were isolated from a crude oil-contaminated soil, and the isolate with the highest crude oil degradation activity, identified as Pseudomonas aeruginosa, was selected. The bioremediation was then investigated and compared between crude oil-contaminated soil (S), the contaminated soil composted with fruit-based waste (SW), and the contaminated soil composted with the same waste with the addition of the selected bacterium (SWB). Both compost-based methods showed high efficiencies of crude oil bioremediation (78.1% and 83.84% for SW and SWB, respectively). However, only a slight difference between the treatments without and with the addition of P. aeruginosa was observed. To make a clear understanding of this point, bacterial communities throughout the 4-week bioremediation period were analyzed. It was found that the community dynamics between both composted treatments were similar, which corresponds with their similar bioremediation efficiencies. Interestingly, Pseudomonas disappeared from the system after one week, which suggests that this genus was not the key degrader or only involved in the early stage of the process. Altogether, our results elaborate that fruit-based composting is an effective approach for crude oil bioremediation.

Lipid Profile, Antioxidant and Antihypertensive Activity, and Computational Molecular Docking of Diatom Fatty Acids as ACE Inhibitors.

Diatoms, as single cell eukaryotic microalgae, are rich sources of lipids, which have either beneficial or detrimental effects on the prevention and treatment of many diseases. Gas chromatography-mass spectrometry (GC-MS) identified diatom lipids with high levels of essential fatty acids (EFAs), especially polyunsaturated FAs (PUFAs) containing both omega-3 and omega-6. Nutritional values of FAs indicated possible applications in the pharmaceutical, nutraceutical, and functional food industries. Diatom FAs showed antioxidative potential on harmful radicals by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) scavenging, with high inhibition of the angiotensin-converting enzyme (ACE) that causes cardiovascular disease (CVD) and hypertension. A computational molecular docking simulation confirmed the inhibition mechanisms of FAs on ACE, with comparable levels of binding free energy to chemically synthesized ACE drugs. Findings suggested that diatom lipids showed potential for use as alternative ACE inhibitors or food supplement for CVD prevention.

Actinobacteria From Desert: Diversity and Biotechnological Applications.

Deserts, as an unexplored extreme ecosystem, are known to harbor diverse actinobacteria with biotechnological potential. Both multidrug-resistant (MDR) pathogens and environmental issues have sharply raised the emerging demand for functional actinobacteria. From 2000 to 2021, 129 new species have been continuously reported from 35 deserts worldwide. The two largest numbers are of the members of the genera Streptomyces and Geodermatophilus, followed by other functional extremophilic strains such as alkaliphiles, halotolerant species, thermophiles, and psychrotolerant species. Improved isolation strategies for the recovery of culturable and unculturable desert actinobacteria are crucial for the exploration of their diversity and offer a better understanding of their survival mechanisms under extreme environmental stresses. The main bioprospecting processes involve isolation of target actinobacteria on selective media and incubation and selection of representatives from isolation plates for further investigations. Bioactive compounds obtained from desert actinobacteria are being continuously explored for their biotechnological potential, especially in medicine. To date, there are more than 50 novel compounds discovered from these gifted actinobacteria with potential antimicrobial activities, including anti-MDR pathogens and anti-inflammatory, antivirus, antifungal, antiallergic, antibacterial, antitumor, and cytotoxic activities. A range of plant growth-promoting abilities of the desert actinobacteria inspired great interest in their agricultural potential. In addition, several degradative, oxidative, and other functional enzymes from desert strains can be applied in the industry and the environment. This review aims to provide a comprehensive overview of desert environments as a remarkable source of diverse actinobacteria while such rich diversity offers an underexplored resource for biotechnological exploitations.

Performance of Actinobacteria isolated from rhizosphere soils on plant growth promotion under cadmium toxicity.

This work aimed to evaluate the potential use of plant growth-promoting actinobacteria (PGPA) for enhanced cadmium (Cd) phytoremediation and plant growth. Forty-two actinobacteria were isolated from rhizosphere soils in Thailand. Among isolates tested, only Streptomyces phaeogriseichromatogenes isolate COS4, showed the high ability to produce siderophores as a plant growth stimulant and had a strong Cd tolerance potential. The significance of siderophores production and Cd tolerance ability under different Cd concentrations suggests the potential of isolate COS4 to work effectively. Plant culture revealed that the significant increase in root length, root to tip length, and total dried weight of sunflower were obtained after 2 h incubation of sunflower seeds with isolate COS4. The efficiency of Cd uptake was found to range between 42.3 and 61.3%. Translocation factor results confirmed that plant growth promoting S. phaeogriseichromatogenes isolate COS4-assisted phytoremediation can be considered as Cd absorbents for the restoration of polluted sites due to high translocation values.

Nonomuraea antri sp. nov., an actinomycete isolated from cave soil in Thailand.

A novel actinobacterium, designated strain NN258T, was isolated from a cave soil sample collected from a karst cave at Khao No-Khao Kaeo, Nakhon Sawan province, Thailand. The morphological, chemotaxonomic and phylogenetic characteristics were consistent with its classification in the genus Nonomuraea. Strain NN258T showed the highest 16S rRNA gene sequence similarity values to Nonomuraea candida HMC10T, Nonomuraea mesophila 6K102T, Nonomuraea rubra DSM 43768T, Nonomuraea diastatica KC712T and Nonomuraea helvata IFO 14681T. The strain formed an extensively branched substrate and aerial mycelia. The whole-cell hydrolysates contained meso-diaminopimelic acid as the diagnostic diamino acid, with glucose, madurose, mannose and ribose as the whole-cell sugars. The polar lipids were diphosphatidylglycerol, phosphotidylmethylethanolamine, phosphatidylethanolamine, hydroxy-phosphatidylmonomethylethanolamine, hydroxy-phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside, two unidentified phospholipids, three unidentified sugar-containing phosphoaminolipids, an unidentified glycolipid and two unidentified lipids. The predominant menaquinone was MK-9(H4), with minor amounts of MK-9(H0), MK-9(H2) and MK-9(H6). Major cellular fatty acids (>10%) were iso-C16 : 0 and 10-methyl-C17 : 0. The G+C content of the genomic DNA was 71.0 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain NN258T and the reference strains were 79.9-80.9 % and 26.1-27.0 %, respectively. On the basis of phenotypic, genotypic and phylogenetic data, strain NN258T represents a novel species of the genus Nonomuraea, for which the name Nonomuraea antri sp. nov. is proposed. The type strain is NN258T (=TBRC 11478T=NBRC 114269T).

New Antimicrobial Phenyl Alkenoic Acids Isolated from an Oil Palm Rhizosphere-Associated Actinomycete, Streptomyces palmae CMU-AB204T.

Basal stem rot (BSR), or Ganoderma rot disease, is the most serious disease associated with the oil palm plant of Southeast Asian countries. A basidiomycetous fungus, Ganoderma boninense, is the causative microbe of this disease. To control BSR in oil palm plantations, biological control agents are gaining attention as a major alternative to chemical fungicides. In the course of searching for effective actinomycetes as potential biological control agents for BSR, Streptomyces palmae CMU-AB204T was isolated from oil palm rhizosphere soil collected on the campus of Chiang Mai University. The culture broth of this strain showed significant antimicrobial activities against several bacteria and phytopathogenic fungi including G. boninense. Antifungal and antibacterial compounds were isolated by antimicrobial activity-guided purification using chromatographic methods. Their structures were elucidated by spectroscopic techniques, including Nuclear Magnetic Resonance (NMR), Mass Spectrometry (MS), Ultraviolet (UV), and Infrared (IR) analyses. The current study isolated new phenyl alkenoic acids 1-6 and three known compounds, anguinomycin A (7), leptomycin A (8), and actinopyrone A (9) as antimicrobial agents. Compounds 1 and 2 displayed broad antifungal activity, though they did not show antibacterial activity. Compounds 3 and 4 revealed a strong antibacterial activity against both Gram-positive and Gram-negative bacteria including the phytopathogenic strain Xanthomonas campestris pv. oryzae. Compounds 7-9 displayed antifungal activity against Ganoderma. Thus, the antifungal compounds obtained in this study may play a role in protecting oil palm plants from Ganoderma infection with the strain S. palmae CMU-AB204T.

Quantitative analysis of methane and glycolate production from microalgae using undiluted wastewater obtained from chicken-manure biogas digester.

Microalgal biomass is often used as a raw material in methane production. Some microalgae possess a complex cell-wall structure which has a low degradability of microorganisms in anaerobic digestion. However, some microalgae produce glycolate, which is excreted outside the cell and can be used to produce methane under anaerobic condition. This research aims to investigate microalgal cultivation using wastewater to reduce nutrients and efficiently create glycolate. Two strains of microalgae (Acutodesmus sp. AARL G023, Chlorella sp. AARL G049) and two microalgal consortia were cultivated at dilutions of 0.5-fold (W50), 0.75-fold (W75) and undiluted wastewater (W100). The results showed that the microalgal consortium with undiluted wastewater (WCW100) consisted of Leptolyngbya sp. (30.4%), Chlorella sp. (16.1%) and Chlamydomonas sp. (52.2%), revealed the highest biomass productivity at 64.38 ± 14.54 mg·L-1·d-1 and the highest glycolate productivity at 5.12 ± 0.48 mmol·L-1·d-1. The cultivation of microalgae effectively reduced ammonium­nitrogen (NH4+-N) and soluble reactive phosphorus (SRP) levels in the wastewater at 43.5 ± 1.3% and 49.6 ± 6.9%. Furthermore, WCW100 showed the highest biogas productivity at 1.44 ± 0.07 mL·g-1·d-1 and the highest methane content at 58.3 ± 6.0% v/v. This study indicates that there is a definite potential of using undiluted wastewater for microalgal biomass production and glycolate production that can reduce the wastewater volume and be applied as a raw material for methane production.

Cave Actinobacteria as Producers of Bioactive Metabolites.

Recently, there is an urgent need for new drugs due to the emergence of drug resistant pathogenic microorganisms and new infectious diseases. Members of phylum Actinobacteria are promising source of bioactive compounds notably antibiotics. The search for such new compounds has shifted to extreme or underexplored environments to increase the possibility of discovery. Cave ecosystems have attracted interest of the research community because of their unique characteristics and the microbiome residing inside including actinobacteria. At the time of writing, 47 species in 30 genera of actinobacteria were reported from cave and cave related habitats. Novel and promising bioactive compounds have been isolated and characterized. This mini-review focuses on the diversity of cultivable actinobacteria in cave and cave-related environments, and their bioactive metabolites from 1999 to 2018.

Amycolatopsis oliviviridis sp. nov., a novel polylactic acid-bioplastic-degrading actinomycete isolated from paddy soil.

A novel bioplastic-degrading actinomycete, strain SCM_MK2-4T, was isolated from paddy soil in Thailand. The 16S rRNA gene sequence showed that strain SCM_MK2-4T belonged to the genus Amycolatopsis, with the highest sequence similarity to Amycolatopsisazurea JCM 3275T (99.4 %), and was phylogenetically clustered with this strain along with Amycolatopsislurida JCM 3141T (99.3 %), A. japonica DSM 44213T (99.2 %), A. decaplanina DSM 44594T (99.0 %), A. roodepoortensis M29T (98.9 %), A. keratiniphilasubsp. nogabecina DSM 44586T (98.8 %), A. keratiniphilasubsp. keratiniphila DSM 44409T (98.5 %), A. orientalis DSM 40040T (98.4 %) and A. regifaucium GY080T (98.3 %). A combination of DNA-DNA hybridization results ranging from 42.8±3.2 to 66.2±1.4 % with the type strains of A. azurea and A. lurida and some different phenotypic characteristics indicated that the strain could be distinguished from its closest phylogenetic neighbours. Whole-cell hydrolysates of the strain were shown to contain meso-diaminopimelic acid, arabinose, galactose, glucose, ribose, mannose, rhamnose and xylose. The predominant menaquinone was MK-9(H4). The major cellular fatty acid profile consisted of iso-C15 : 0, iso-C16 : 0, summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2OH) and C16 : 0. The polar lipid composition of the strain consisted of phosphatidyl-N-methylethylethanolamine, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylglycerol, aminophospholipids, an unidentified phospholipid and two unidentified glycolipids. The G+C content of the genomic DNA was 68.2 mol%. On the basis of phylogenetic analyses, DNA-DNA hybridization experimentation and the phenotypic characteristics, it was concluded that strain SCM_MK2-4T represents a novel species of the genus Amycolatopsis, for which the name Amycolatopsis oliviviridis sp. nov. is proposed. The type strain is SCM_MK2-4T (=TBRC 7186T=JCM 32134T).

Amycolatopsis vastitatis sp. nov., an isolate from a high altitude subsurface soil on Cerro Chajnantor, northern Chile.

The taxonomic position of a novel Amycolatopsis strain isolated from a high altitude Atacama Desert subsurface soil was established using a polyphasic approach. The strain, isolate H5T, was shown to have chemical properties typical of members of the genus Amycolatopsis such as meso-diaminopimelic acid as the diamino acid in the cell wall peptidoglycan, arabinose and galactose as diagnostic sugars and MK-9(H4) as the predominant isoprenologue. It also has cultural and morphological properties consistent with its classification in the genus, notably the formation of branching substrate hyphae which fragment into rod-like elements. 16S rRNA gene sequence analyses showed that the strain is closely related to the type strain of Amycolatopsis mediterranei but could be distinguished from this and other related Amycolatopsis strains using a broad range of phenotypic properties. It was separated readily from the type strain of Amycolatopsis balhymycina, its near phylogenetic neighbour, based on multi-locus sequence data, by low average nucleotide identity (92.9%) and in silico DNA/DNA relatedness values (51.3%) calculated from draft genome assemblies. Consequently, the strain is considered to represent a novel species of Amycolatopsis for which the name Amycolatopsis vastitatis sp. nov. is proposed. The type strain is H5T (= NCIMB 14970T = NRRL B-65279T).

Pseudonocardia thailandensis sp. nov., an actinomycete isolated from a subterranean termite nest.

A novel Gram-stain-positive bacterium designated CMU-NKS-70T was isolated from a subterranean termite nest and characterized using a polyphasic approach. The strain exhibited branching, pinkish-cream aerial mycelium and cream-brown substrate mycelium, and formed chains of rod-like spores. The 16S rRNA gene sequence analyses indicated that strain CMU-NKS-70T belonged to the genus Pseudonocardia, showing high similarity with Pseudonocardia oroxyli D10T (98.9 % 16S rRNA gene sequence similarity), Pseudonocardia xishanensis YIM 63638T (98.9 %) and Pseudonocardia kujensis A4038T (98.5 %). However, DNA-DNA relatedness values between strains CMU-NKS-70T and the closest phylogenetically related species ranged from 40.5±2.9 to 48.6±0.7 %. Whole-cell hydrolysates of strain CMU-NKS-70T consisted of meso-diaminopimelic acid, glucose, galactose, arabinose, mannose, ribose and rhamnose. The predominant menaquinone was MK-8(H4). The major cellular fatty acids (>10 %) were iso-C16 : 0, C16 : 0, C16 : 1ω7c and/or iso-C15 : 0 2-OH and 10-methyl C16 : 0. The polar lipids detected were phosphatidylethanolamine, phosphatidylmethylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, three unidentified glycolipids and two unidentified phospholipids. The G+C content of genomic DNA was 71.9 mol%. The physiological and biochemical properties also supported the phenotypic distinction of strain CMU-NKS-70T from its closely related species. On the basis of evidence from this study using a polyphasic approach, strain CMU-NKS-70T represents a novel species of the genus Pseudonocardia for which the name Pseudonocardia thailandensis sp. nov. is proposed. The type strain is CMU-NKS-70T (=JCM 31292T=TBRC 2000T).

Streptomyces palmae sp. nov., isolated from oil palm (Elaeis guineensis) rhizosphere soil.

Actinomycete strain CMU-AB204T was isolated from oil palm rhizosphere soil collected in Chiang Mai University (Chiang Mai, Thailand). Based on morphological and chemotaxonomic characteristics, the organism was considered to belong to the genus Streptomyces. Whole cell-wall hydrolysates consisted of ll-diaminopimelic acid, glucose, ribose and galactose. The predominant menaquinones were MK-9(H4), MK-9(H6), MK-9(H2) and MK-8(H4). The fatty acid profile contained iso-C15 : 0, iso-C16 : 0 and anteiso-C15 : 0 as major components. The principal phospholipids detected were phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. The DNA G+C content of strain CMU-AB204T was 70.9 mol%. Based on 16S rRNA gene sequence similarity, strain CMU-AB204T was closely related to Streptomyces orinoci JCM 4546T (98.7 %), Streptomyces lilacinus NBRC 12884T (98.5 %), Streptomyces abikoensis CGMCC 4.1662T (98.5 %), Streptomyces griseocarneus JCM 4905T (98.4 %) and Streptomyces xinghaiensis JCM 16958T (98.3 %). Phylogenetic trees revealed that the new strain had a distinct taxonomic position from closely related type strains of the genus Streptomyces. Spiny to hairy spores clearly differentiated strain CMU-AB204T from the five most closely related Streptomyces species, which produced smooth spores. On the basis of evidence from this polyphasic study, it is proposed that strain CMU-AB204T represents a novel species of the genus Streptomyces, namely Streptomyces palmae sp. nov. The type strain is CMU-AB204T (=JCM 31289T=TBRC 1999T).

Actinopolyspora salinaria sp. nov., a halophilic actinomycete isolated from solar saltern soil.

The taxonomic position of the halophilic actinobacterial strain, HS05-03T, isolated from solar saltern soil, was determined using a polyphasic approach. Phylogenetic analysis based on the 16S rRNA gene sequence of the strain showed that it formed a distinct evolutionary lineage in the genus Actinopolyspora. The organism was most closely related to the type strains of the species Actinopolyspora xinjiangensis (98.0% similarity), Actinopolyspora righensis (97.9% similarity), Actinopolyspora lacussalsi (97.9% similarity) and Actinopolyspora erythraea (97.8% similarity). The whole-organism hydrolysates contained meso-diaminopimelic acid, arabinose, galactose and ribose. The predominant menaquinones were found to be MK-9(H4) and MK-10(H4). The acyl type of the peptidoglycan was N-acetyl. The diagnostic phospholipid detected was phosphatidylcholine. The predominant cellular fatty acids were iso-C16 : 0, anteiso-C17:0 and iso-C15:0. The G+C content of the genomic DNA was 69.9 mol%. DNA-DNA hybridization values between strain HS05-03T and the type strains of the most closely related species were below the 70 % threshold. On the basis of the phenotypic and genotypic data, it is proposed that strain HS05-03T represents a novel species of the genus Actinopolyspora, with the name Actinopolyspora salinaria sp. nov. The type strain is HS05-03T (=BCC 51286T=NBRC 109078T).

Jiangella mangrovi sp. nov., isolated from mangrove soil.

An aerobic, Gram-stain-positive actinomycete, designated strain 3SM4-07T, was characterized using a polyphasic taxonomic approach. The strain produced branching mycelium which fragmented into short or elongated rods. The whole-cell hydrolysates contained ll-2,6-diaminopimelic acid as the diagnostic diamino acid, with glucose and ribose as the main sugars. The predominant cellular fatty acids were anteiso-C15  :  0, iso-C15  :  0 and iso-C16  :  0.The predominant menaquinone was MK-9(H4). Phospholipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylinositol and phosphatidylinositol mannoside. Mycolic acids were absent. The DNA G+C content was 72.3 mol%. Strain 3SM4-07T formed a phylogenetic line within the genus Jiangella and its 16S rRNA gene sequence was related most closely to Jiangella alkaliphila D8-87T (99.0% similarity), Jiangella muralis 15-Je-017T (98.8%), Jiangella alba YIM 61503T (98.6%) and Jiangella gansuensis YIM 002T (98.6%). However, mean DNA-DNA hybridization values revealed that strain 3SM4-07T differed from the closest species previously described in this genus. Data from phenotypic, chemotaxonomic and molecular analyses between strain 3SM4-07T and recognized species of the genus Jiangella indicate that strain 3SM4-07T is a representative of a novel species of the genus Jiangella, for which the name Jiangella mangrovi sp. nov. is proposed. The type strain is 3SM4-07T ( = BCC 60398T = NBRC 109648T).

Allokutzneria oryzae sp. nov., isolated from rhizospheric soil of Oryza sativa L.

The taxonomic status of a rhizospheric soil actinomycete, designated R8-39(T), was established using a polyphasic approach. The organism had phenotypic and morphological characteristics consistent with its classification in the genus Allokutzneria. Phylogenetic analysis based on an almost complete 16S rRNA gene sequence showed that the strain formed a monophyletic clade with the type strains of members of the genus Allokutzneria. Strain R8-39(T) displayed the highest levels of 16S rRNA gene sequence similarity to Allokutzneria albata DSM 44149(T) (98.8%) and Allokutzneria multivorans YIM 120521(T) (98.3%). However, the DNA-DNA hybridization values between strain R8-39(T) and A. albata and A. multivorans were clearly below the 70% threshold. The organism was found to have chemical characteristics consistent with its classification in the genus Allokutzneria. Whole-cell hydrolysates contained meso-diaminopimelic acid, arabinose, galactose, glucose, mannose, rhamnose and ribose. The main menaquinone was MK-9(H4). No mycolic acid was detected. The G+C content of the genomic DNA was 71.8 mol%. In addition, strain R8-39(T) had a phenotypic profile that readily distinguished it from recognized representatives of the genus Allokutzneria. It is evident from the combined genotypic and phenotypic properties that strain R8-39(T) represents a novel species of the genus Allokutzneria. The proposed name for this species is Allokutzneria oryzae sp. nov.; the type strain is R8-39(T) ( = BCC 60399(T) = NBRC 109649(T)).

Verrucosispora fiedleri sp. nov., an actinomycete isolated from a fjord sediment which synthesizes proximicins.

A novel filamentous actinobacterial organism, designated strain MG-37(T), was isolated from a Norwegian fjord sediment and examined using a polyphasic taxonomic approach. The organism was determined to have chemotaxonomic and morphological properties consistent with its classification in the genus Verrucosispora and formed a distinct phyletic line in the Verrucosispora 16S rRNA gene tree. It was most closely related to Verrucosispora maris DSM 45365(T) (99.5 % 16S rRNA gene similarity) and Verrucosispora gifhornensis DSM 44337(T) (99.4 % 16S rRNA gene similarity) but was distinguished from these strains based on low levels of DNA:DNA relatedness (~56 and ~50 %, respectively). It was readily delineated from all of the type strains of Verrucosispora species based on a combination of phenotypic properties. Isolate MG-37(T) (=NCIMB 14794(T) = NRRL-B-24892(T)) should therefore be classified as the type strain of a novel species of Verrucosispora for which the name Verrucosispora fiedleri is proposed.

Microbispora thailandensis sp. nov., an actinomycete isolated from cave soil.

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)).

Sphaerisporangium siamense sp. nov., an actinomycete isolated from rubber-tree rhizospheric soil.

A Gram-positive aerobic actinomycete, designated SR14.14(T), isolated from the rhizospheric soil of rubber tree was determined taxonomically using a polyphasic approach. The organism contained meso-diaminopimelic acid and the N-acetyl type of peptidoglycan. The predominant menaquinones were MK-9, MK-9(H2) and MK-9(H4). Madurose was detected in the whole-cell hydrolysates. Mycolic acids were not presented. Major phospholipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol mannoside. Major cellular fatty acid was iso-C(16:0) and the G+C content was 71.9 mol %. Phylogenetic analysis based on 16S rRNA gene sequence suggested that the isolate belongs to the genus Sphaerisporangium. The sequence similarity value between the strain SR14.14(T) and its closely related species, Sphaerisporangium album, was 97.8%. DNA-DNA hybridization values between them were well below 70%. Based on genotypic and phenotypic data, strain SR14.14(T) represents a novel species in the genus Sphaerisporangium, for which the name Sphaerisporangium siamense sp. nov. is proposed. The type strain is SR14.14(T) (=BCC 41491(T)=NRRL B-24805(T)=NBRC 107570(T)).