Nocardiopsis xinjiangensis sp. nov., a halophilic actinomycete isolated from a saline soil sample in China

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

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

From ecophysiology to cultivation methodology: filling the knowledge gap between uncultured and cultured microbes

Earth is dominated by a myriad of microbial communities, but the majority fails to grow under in situ laboratory conditions. The basic cause of unculturability is that bacteria dominantly occur as biofilms in natural environments. Earlier improvements in the culture techniques are mostly done by optimizing media components. However, with technological advancement particularly in the field of genome sequencing and cell imagining techniques, new tools have become available to understand the ecophysiology of microbial communities. Hence, it becomes easier to mimic environmental conditions in the culture plate. Other methods include co-culturing, emendation of growth factors, and cultivation after physical cell sorting. Most recently, techniques have been proposed for bacterial cultivation by employing genomic data to understand either microbial interactions (network-directed targeted bacterial isolation) or ecosystem engineering (reverse genomics). Hopefully, these techniques may be applied to almost all environmental samples, and help fill the gaps between the cultured and uncultured microbial communities.

Nocardiopsis dassonvillei subsp. crassaminis subsp. nov., isolated from freshwater sediment, and reappraisal of Nocardiopsis alborubida Grund and Kroppenstedt 1990 emend. Nouioui et al. 2018

An actinomycete, strain D1^T, was isolated from a freshwater sediment sample collected from the San Pablo river in the La Risueña community, Santiago de Cuba province, Cuba. The strain was identified as a member of the genus Nocardiopsis by means of a polyphasic taxonomic study. It produced a light yellow non-fragmented substrate mycelium, a white well-developed aerial mycelium and straight to flexuous hyphae. No specific spore chains were observed. Strain D1^T contained meso-diaminopimelic acid, no diagnostic sugars, and MK-10(H₂), MK-10(H₄), MK-10 and MK-10(H₆) as predominant menaquinones, but not phosphatidylcholine as diagnostic polar lipid of the genus Nocardiopsis. The predominant fatty acids were iso-C_16 : 0, 10-methyl-C_18 : 0 and anteiso-C_17 : 0. Strain D1^T showed the highest degree of 16S rRNA gene sequence similarity to Nocardiopsis synnematoformans DSM 44143^T (99.8 %), Nocardiopsis dassonvillei subsp. albirubida NBRC 13392^T (99.8 %) and Nocardiopsis dassonvillei subsp. dassonvillei DSM 43111^T (99.6 %). A genomic OrthoANIu value between D1^T and N. dassonvillei subsp. dassonvillei DSM 43111^T of 97.63 % and a dDDH value of 78.9 % indicated that strain D1^T should be classified in N. dassonvillei. However, phenotypic characteristics distinguished strain D1^T from its nearest neighbour taxon. On basis of these results we propose to classify strain D1^T (=LMG 30468^T=CECT 30033^T) as a representative of a novel subspecies of the genus Nocardiopsis, for which the name Nocardiopsis dassonvillei subsp. crassaminis subsp. nov. is proposed. In addition, the genomic distance between N. dassonvillei subsp. albirubida NBRC 13392^T and N. dassonvillei subsp. dassonvillei DSM 43111^T as determined through OrthoANIu (93.64 %) and dDDH (53.40 %), along with considerable phenotypic and chemotaxonomic differences reported in earlier studies, indicated that the classification of this taxon as Nocardiopsis alborubida Grund and Kroppenstedt 1990 is to be preferred over its classification as N. dassonvillei subsp. albirubida Evtushenko et al. 2000.

Decoding the biological information contained in two ancient Slavonic parchment codices: an added historical value

This study provides an example in the emerging field of biocodicology showing how metagenomics can help answer relevant questions that may contribute to a better understanding of the history of ancient manuscripts. To this end, two Slavonic codices dating from the 11th century were investigated through shotgun metagenomics. Endogenous DNA enabled to infer the animal origin of the skins used in the manufacture of the two codices, while nucleic sequences recovered from viruses were investigated for the first time in this material, opening up new possibilities in the field of biocodicology. In addition, the microbiomes colonizing the surface of the parchments served to determine their conservation status and their latent risk of deterioration. The saline environment provided by the parchments selected halophilic and halotolerant microorganisms, which are known to be responsible for the biodegradation of parchment. Species of Nocardiopsis, Gracilibacillus and Saccharopolyspora, but also members of the Aspergillaceae family were detected in this study, all possessing enzymatic capabilities for the biodeterioration of this material. Finally, a relative abundance of microorganisms originating from the human skin microbiome were identified, most probably related to the intensive manipulation of the manuscripts throughout the centuries, which should be taken with caution as they can be potential pathogens.

Genome-Based Taxonomic Classification of the Phylum Actinobacteria

The application of phylogenetic taxonomic procedures led to improvements in the classification of bacteria assigned to the phylum Actinobacteria but even so there remains a need to further clarify relationships within a taxon that encompasses organisms of agricultural, biotechnological, clinical, and ecological importance. Classification of the morphologically diverse bacteria belonging to this large phylum based on a limited number of features has proved to be difficult, not least when taxonomic decisions rested heavily on interpretation of poorly resolved 16S rRNA gene trees. Here, draft genome sequences of a large collection of actinobacterial type strains were used to infer phylogenetic trees from genome-scale data using principles drawn from phylogenetic systematics. The majority of taxa were found to be monophyletic but several orders, families, and genera, as well as many species and a few subspecies were shown to be in need of revision leading to proposals for the recognition of 2 orders, 10 families, and 17 genera, as well as the transfer of over 100 species to other genera. In addition, emended descriptions are given for many species mainly involving the addition of data on genome size and DNA G+C content, the former can be considered to be a valuable taxonomic marker in actinobacterial systematics. Many of the incongruities detected when the results of the present study were compared with existing classifications had been recognized from 16S rRNA gene trees though whole-genome phylogenies proved to be much better resolved. The few significant incongruities found between 16S/23S rRNA and whole genome trees underline the pitfalls inherent in phylogenies based upon single gene sequences. Similarly good congruence was found between the discontinuous distribution of phenotypic properties and taxa delineated in the phylogenetic trees though diverse non-monophyletic taxa appeared to be based on the use of plesiomorphic character states as diagnostic features.

Microbial communities associated with the anthropogenic, highly alkaline environment of a saline soda lime, Poland

Soda lime is a by-product of the Solvay soda process for the production of sodium carbonate from limestone and sodium chloride. Due to a high salt concentration and alkaline pH, the lime is considered as a potential habitat of haloalkaliphilic and haloalkalitolerant microbial communities. This artificial and unique environment is nutrient-poor and devoid of vegetation, due in part to semi-arid, saline and alkaline conditions. Samples taken from the surface layer of the lime and from the depth of 2 m (both having pH ~11 and EC_e up to 423 dS m⁻¹) were investigated using culture-based (culturing on alkaline medium) and culture-independent microbiological approaches (microscopic analyses and pyrosequencing). A surprisingly diverse bacterial community was discovered in this highly saline, alkaline and nutrient-poor environment, with the bacterial phyla Proteobacteria (representing 52.8% of the total bacterial community) and Firmicutes (16.6%) showing dominance. Compared to the surface layer, higher bacterial abundance and diversity values were detected in the deep zone, where more stable environmental conditions may occur. The surface layer was dominated by members of the genera Phenylobacterium, Chelativorans and Skermanella, while in the interior layer the genus Fictibacillus was dominant. The culturable aerobic, haloalkaliphilic bacteria strains isolated in this study belonged mostly to the genus Bacillus and were closely related to the species Bacillus pseudofirmus, B. cereus, B. plakortidis, B. thuringensis and B. pumilus.

Nocardiopsis oceani sp. nov. and Nocardiopsis nanhaiensis sp. nov., actinomycetes isolated from marine sediment of the South China Sea

Two actinomycete strains, designated 10A08AT and 10A08BT, were isolated from marine sediment samples of the South China Sea and their taxonomic positions were determined by a polyphasic approach. The two Gram-stain-positive, aerobic strains produced branched substrate mycelium and aerial hyphae, and no diffusible pigment was produced in the media tested. At maturity, spore chains were formed on aerial hyphae and all mycelium fragmented with age. Whole-cell hydrolysates of both strains contained meso-diaminopimelic acid and no diagnostic sugars. Their predominant menaquinones (>10 %) were MK-9(H4), MK-9(H6) and MK-10(H6) for strain 10A08AT and MK-9(H4), MK-9(H6), MK-10(H4) and MK-10(H6) for strain 10A08BT. The polar lipids detected from the two strains were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and unknown phosphoglycolipids and phospholipids. The major fatty acids (>10 %) of both strains were iso-C16 : 0 and summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B). The genomic DNA G+C contents of strains 10A08AT and 10A08BT were 70.9 and 71.6 mol%, respectively. On the basis of 16S rRNA gene sequence similarities, the two strains were shown to be most closely related to species of the genus Nocardiopsis. DNA–DNA hybridization relatedness values of < 70 % between these two isolates and their closest neighbour, Nocardiopsis terrae YIM 90022T, and between the two strains supported the conclusion that they represent two novel species. Based on phylogenetic analysis and phenotypic and genotypic data, it is concluded that the two isolates belong to the genus Nocardiopsis, and the names Nocardiopsis oceani sp. nov. (type strain 10A08AT = DSM 45931T = BCRC 16951T) and Nocardiopsis nanhaiensis sp. nov. (type strain 10A08BT = CGMCC 47227T = BCRC 16952T) are proposed.

Biogeography of Nocardiopsis strains from hypersaline environments of Yunnan and Xinjiang Provinces, western China

The genus Nocardiopsis is a widespread group within the phylum Actinobacteria and has been isolated from various salty environments worldwide. However, little is known about whether biogeography affects Nocardiopsis distribution in various hypersaline environments. Such information is essential for understanding the ecology of Nocardiopsis. Here we analyzed 16S rRNA, gyrB, rpoB and sodA genes of 78 Nocardiopsis strains isolated from hypersaline environments in Yunnan and Xinjiang Provinces of western China. The obtained Nocardiopsis strains were classified into five operational taxonomic units, each comprising location-specific phylo- and genotypes. Statistical analyses showed that spatial distance and environmental factors substantially influenced Nocardiopsis distribution in hypersaline environments: the former had stronger influence at large spatial scales, whereas the latter was more influential at small spatial scales.

Nocardiopsis species: Incidence, ecological roles and adaptations

Members of the genus Nocardiopsis are ecologically versatile and biotechnologically important. They produce a variety of bioactive compounds such as antimicrobial agents, anticancer substances, tumor inducers, toxins and immunomodulators. They also secrete novel extracellular enzymes such as amylases, chitinases, cellulases, β-glucanases, inulinases, xylanases and proteases. Nocardiopsis species are aerobic, Gram-positive, non-acid-fast, catalase-positive actinomycetes with nocardioform substrate mycelia and their aerial mycelia bear long chains of spores. Their DNA possesses high contents of guanine and cytosine. There is a marked variation in properties of the isolates obtained from different ecological niches and their products. An important feature of several species is their halophilic or halotolerant nature. They are associated with a variety of marine and terrestrial biological forms wherein they produce antibiotics and toxins that help their hosts in evading pathogens and predators. Two Nocardiopsis species, namely, N. dassonvillei and N. synnemataformans (among the thirty nine reported ones) are opportunistic human pathogens and cause mycetoma, suppurative infections and abscesses. Nocardiopsis species are present in some plants (as endophytes or surface microflora) and their rhizospheres. Here, they are reported to produce enzymes such as α-amylases and antifungal agents that are effective in warding-off plant pathogens. They are prevalent as free-living entities in terrestrial locales, indoor locations, marine ecosystems and hypersaline habitats on account of their salt-, alkali- and desiccation-resistant behavior. In such natural locations, Nocardiopsis species mainly help in recycling organic compounds. Survival under these diverse conditions is mediated by the production of extracellular enzymes, antibiotics, surfactants, and the accumulation of compatible solutes. The accommodative genomic features of Nocardiopsis species support their existence under the diverse conditions where they prevail.

Allosalinactinospora lopnorensis gen. nov., sp. nov., a new member of the family Nocardiopsaceae isolated from soil

A novel actinomycete, designated strain CA15-2T, was isolated from a soil sample collected from the rhizosphere of tamarisk in the Lop Nor region, Xinjiang, China, and was characterized by using a polyphasic taxonomic approach. Optimal growth occurred at 37 °C and pH 7.5–8.0 and with 5 % (w/v) NaCl. Strain CA15-2T formed white to pale-yellow branched substrate mycelium without fragmentation and sparse aerial mycelium with wavelike curves. Whole-cell hydrolysates of the isolate contained meso-diaminopimelic acid as the diagnostic diamino acid of the cell wall but no diagnostic sugars. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylmethylethanolamine, phosphatidylethanolamine, one unidentified glycolipid, one unidentified phospholipid and other unidentified lipids. MK-9(H8), MK-10(H8) and MK-10(H6) were the predominant menaquinones. The major fatty acids were iso-C16 : 0 and C16 : 0. The G+C content of the genomic DNA was 69.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CA15-2T formed a distinct subclade in the family Nocardiopsaceae , with less than 95 % 16S rRNA gene sequence similarity to all known members of the family Nocardiopsaceae . On the basis of the evidence from our polyphasic study, a novel genus, Allosalinactinospora gen. nov., is proposed, with the type species Allosalinactinospora lopnorensis gen. nov., sp. nov. The type strain of Allosalinactinospora lopnorensis is strain CA15-2T ( = DSM 45697T = CGMCC 4.7074T).

Nocardiopsis species as potential sources of diverse and novel extracellular enzymes

Members of the genus Nocardiopsis are generally encountered in locations that are inherently extreme. They are present in frozen soils, desert sand, compost, saline or hypersaline habitats (marine systems, salterns and soils) and alkaline places (slag dumps, lake soils and sediments). In order to survive under these severe conditions, they produce novel and diverse enzymes that allow them to utilize the available nutrients and to thrive. The members of this genus are multifaceted and release an assortment of extracellular hydrolytic enzymes. They produce enzymes that are cold-adapted (α-amylases), thermotolerant (α-amylases and xylanases), thermoalkalotolerant (cellulases, β-1,3-glucanases), alkali-tolerant thermostable (inulinases), acid-stable (keratinase) and alkalophilic (serine proteases). Some of the enzymes derived from Nocardiopsis species act on insoluble polymers such as glucans (pachyman and curdlan), keratin (feathers and prion proteins) and polyhydroxyalkanoates. Extreme tolerance exhibited by proteases has been attributed to the presence of some amino acids (Asn and Pro) in loop structures, relocation of multiple salt bridges to outer regions of the protein or the presence of a distinct polyproline II helix. The range of novel enzymes is projected to increase in the forthcoming years, as new isolates are being continually reported, and the development of processes involving such enzymes is envisaged in the future.

Nocardiopsis fildesensis sp. nov., an actinomycete isolated from soil

A filamentous actinomycete strain, designated GW9-2T, was isolated from a soil sample collected from the Fildes Peninsula, King George Island, West Antarctica. The strain was identified using a polyphasic taxonomic approach. The strain grew slowly on most media tested, producing small amounts of aerial mycelia and no diffusible pigments on most media tested. The strain grew in the presence of 0–12 % (w/v) NaCl (optimum, 2–4 %), at pH 9.0–11.0 (optimum, pH 9.0) and 10–37 °C (optimum, 28 °C). The isolate contained meso-diaminopimelic acid, no diagnostic sugars and MK-9(H4) as the predominant menaquinone. The major phospholipids were phosphatidylglycerol, phosphatidylcholine and phosphatidylmethylethanolamine. The major fatty acids were iso-C16 : 0, anteiso-C17 : 0, C18 : 1ω9c, iso-C15 : 0 and iso-C17 : 0. DNA–DNA relatedness was 37.6 % with Nocardiopsis lucentensis DSM 44048T, the nearest phylogenetic relative (97.93 % 16S rRNA gene sequence similarity). On the basis of the results of a polyphasic study, a novel species, Nocardiopsis fildesensis sp. nov., is proposed. The type strain is GW9-2T ( = CGMCC 4.7023T = DSM 45699T = NRRL B-24873T).

Systematic and biotechnological aspects of halophilic and halotolerant actinomycetes

More than 70 species of halotolerant and halophilic actinomycetes belonging to at least 24 genera have been validly described. Halophilic actinomycetes are a less explored source of actinomycetes for discovery of novel bioactive secondary metabolites. Degradation of aliphatic and aromatic organic compounds, detoxification of pollutants, production of new enzymes and other metabolites such as antibiotics, compatible solutes and polymers are other potential industrial applications of halophilic and halotolerant actinomycetes. Especially new bioactive secondary metabolites that are derived from only a small fraction of the investigated halophilic actinomycetes, mainly from marine habitats, have revealed the huge capacity of this physiological group in production of new bioactive chemical entities. Combined high metabolic capacities of actinomycetes and unique features related to extremophilic nature of the halophilic actinomycetes have conferred on them an influential role for future biotechnological applications.

Nocardiopsis coralliicola sp. nov., isolated from the gorgonian coral, Menella praelonga

An actinobacterial strain, SCSIO 10427T, was isolated from a gorgonian coral sample collected from Weizhou Island, Guangxi province, China, and its taxonomic position was investigated using a polyphasic approach. The organism was found to have a range of chemical and morphological properties consistent with its classification in the genus Nocardiopsis . Phylogenetic analysis indicated that 16S rRNA gene sequence similarity between strain SCSIO 10427T and type strains of other recognized members of the genus Nocardiopsis was lower than 98.4 %. Furthermore, phenotypic characteristics revealed that the strain differed from the currently recognized species of the genus Nocardiopsis . Therefore, strain SCSIO 10427T represents a novel species of the genus Nocardiopsis , for which the name Nocardiopsis coralliicola sp. nov. is proposed. The type strain is SCSIO 10427T ( = CCTCC AA 2011010T = DSM 45611T).

Salinactinospora qingdaonensis gen. nov., sp. nov., a halophilic actinomycete isolated from a salt pond

A novel halophilic, filamentous, actinomycete strain, designated CXB832T, was isolated from a salt pond in Qingdao, China. Optimal growth occurred at 37 °C, pH 7.0–8.0 and 9–12 % (w/v) NaCl. Strain CXB832T formed pale yellow to deep yellow branched substrate mycelium without fragmentation. Abundant white aerial mycelium differentiated into long chains of spores and the spores were rod-shaped with smooth surfaces. Strain CXB832T contained meso-diaminopimelic acid as the diagnostic diamino acid of the cell-wall peptidoglycan, and glucose and xylose as the major whole-cell sugars. The phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phospholipids, glycolipid and unidentified lipids. MK-10(H8), MK-9(H8), MK-10(H2) and MK-10(H6) were the predominant menaquinones. The major fatty acids were i-C16 : 0 (30.71 %), ai-C17 : 0 (13.31 %) and C16 : 0 (11.28 %). The G+C content of the DNA was 60.1 mol%. Comparative analysis of 16S rRNA gene sequences showed that the novel strain was most closely related to genera within the family Nocardiopsaceae , but formed a separate lineage. The highest sequence similarities were to Nocardiopsis arabia DSM 45083T (95.4 %) and Haloactinospora alba DSM 45015T (94.9 %). On the basis of phenotypic, chemotaxonomic and phylogenetic distinctiveness, strain CXB832T represents a new genus and novel species in the family Nocardiopsaceae , for which the name Salinactinospora qingdaonensis gen. nov., sp. nov. is proposed. The type strain of the type species is CXB832T ( = DSM 45442T = LMG 25567T).

Spinactinospora alkalitolerans gen. nov., sp. nov., an actinomycete isolated from marine sediment

A novel marine actinomycete, designated CXB654T, was isolated from marine sediment collected at a depth of 17.5 m near the Yellow Sea Cold Water Mass, China. Optimal growth occurred at 37.0 °C, at pH 7.0–8.0 and in 3–8 % (w/v) NaCl. Strain CXB654T formed branched substrate mycelium without fragmentation. Abundant aerial mycelium differentiated into long or short chains of spores and spores were elliptical and cylindrical with spiny surfaces. Strain CXB654T contained meso-diaminopimelic acid as the diagnostic diamino acid, and ribose and glucose as the major whole-cell components. Phospholipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol and phosphatidylinositol. MK-10(H8), MK-10(H6) and MK-9(H8) were the predominant menaquinones. The major fatty acids were i-C16 : 0 (24.46 %), ai-C17 : 0 (20.66 %) and C18 : 0 (20.14 %). The DNA G+C content was 71.1 mol%. Comparative analysis of 16S rRNA gene sequences showed that the novel strain was most closely related to genera within the family Nocardiopsaceae, but formed a separate lineage. Highest sequence similarities were to Murinocardiopsis flavida DSM 45312T (96.6 %), Thermobifida halotolerans YIM 90462T (96.5 %) and Marinactinospora thermotolerans DSM 45154T (96.1 %). On the basis of phenotypic, chemotaxonomic and phylogenetic distinctiveness, strain CXB654T was considered to represent a novel species in a new genus in the family Nocardiopsaceae, and the name Spinactinospora alkalitolerans gen. nov., sp. nov. is proposed; the type strain is CXB654T ( = DSM 45414T = LMG 25485T).

Nocardiopsis nikkonensis sp. nov., isolated from a compost sample

An actinomycete strain, designated YU1183-22T, was isolated from a compost sample collected in Nikko, Japan. The isolate formed white aerial mycelium with relatively long aerial hyphae showing chains of arthrospores. Strain YU1183-22T grew with 0–10 % (w/v) NaCl, at pH 6–11 and at 10–37 °C (optimum 30 °C). Strain YU1183-22T contained meso-diaminopimelic acid and no diagnostic sugars. The predominant menaquinones were MK-10(H10) and MK-10(H8). The polar lipids were phosphatidylcholine and phosphatidylglycerol. The major cellular fatty acids were iso-C16 : 0, anteiso-C17 : 0 and tuberculostearic acid. The G+C content of the DNA was 72.3 mol%. Chemotaxonomic and morphological characterization clearly demonstrated that strain YU1183-22T belonged to the genus Nocardiopsis. Phylogenetic analysis using 16S rRNA gene sequences showed that the isolate was closely related to Nocardiopsis salina YIM 90010T (98.0 % 16S rRNA gene sequence similarity), Nocardiopsis xinjiangensis YIM 90004T (97.9 %) and Nocardiopsis kunsanensis HA-9T (97.3 %). However, DNA–DNA relatedness as well as physiological and biochemical analyses showed that strain YU1183-22T could be differentiated from its closest phylogenetic relatives. It is proposed that this strain be classified as a representative of a novel species of the genus Nocardiopsis, with the name Nocardiopsis nikkonensis sp. nov. The type strain is YU1183-22T (=NBRC 102170T =KCTC 19666T).

Murinocardiopsis flavida gen. nov., sp. nov., an actinomycete isolated from indoor walls

Two Gram-stain-positive, mycelium-forming actinobacteria (strains 14-Be-013T and 02-Gi-014) were isolated from walls colonized with moulds and studied taxonomically. The isolates formed yellowish-pigmented substrate mycelium showing no fragmentation. Comparative analysis of 16S rRNA gene sequences showed that these bacteria are most closely related to genera within the family Nocardiopsaceae, but form a separate lineage within this family. Highest sequence similarities were to the type strains of Marinactinospora thermotolerans (96.0 % to 14-Be-013T), Nocardiopsis dassonvillei subsp. albirubida and Nocardiopsis lucentensis (both 95.3 % to 14-Be-013T). Whole-cell hydrolysates contained meso-diaminopimelic acid as the diagnostic diamino acid of the cell wall and no diagnostic sugars. Mycolic acids were absent. The major menaquinones were MK-10(H4), MK-11(H4) and MK-12(H2). The polar lipid profile consisted of phosphatidylcholine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and unknown lipids. Major fatty acids iso-C16 : 0, anteiso-C17 : 0 and C18 : 1 ω9c supported the affiliation of these isolates to the family Nocardiopsaceae. Phenotypic analysis (including chemotaxonomy) further differentiated strains 14-Be-013T and 02-Gi-014 from the most closely related members of the genera Marinactinospora and Nocardiopsis. Since the two strains form a distinct lineage in the 16S rRNA gene sequence-based phylogenetic tree, the novel genus Murinocardiopsis gen. nov. with the type species Murinocardiopsis flavida sp. nov. is proposed. The type strain of Murinocardiopsis flavida is 14-Be-013T (=DSM 45312T =CCM 7612T).

Nocardiopsis litoralis sp. nov., a halophilic marine actinomycete isolated from a sea anemone

A Gram-positive, moderately halophilic, alkalitolerant, filamentous, aerobic actinomycete, designated strain JSM 073097(T), was isolated from a sea anemone collected from a tidal flat in the South China Sea. Phylogenetic analyses based on 16S rRNA gene sequences indicated that the new isolate was a member of the genus Nocardiopsis and was most closely related to Nocardiopsis kunsanensis HA-9(T), Nocardiopsis xinjiangensis YIM 90004(T) and Nocardiopsis salina YIM 90010(T) (99.6, 98.5 and 98.1 % similarity, respectively). Phenotypic characteristics and chemotaxonomic data also indicated that strain JSM 073097(T) was a member of the genus Nocardiopsis. The strain grew well on most of the media tested, producing white to yellow-white substrate mycelium and white aerial mycelium and straight to flexuous hyphae. The substrate mycelium was well developed and fragmented with age; the aerial mycelium produced long, straight to flexuous spore chains with non-motile, smooth-surfaced, rod-shaped spores. The strain grew in the presence of 1-15 % (w/v) total salts and at pH 6.0-10.5 and 20-35 degrees C; optimum growth occurred in the presence of 5-7 % (w/v) total salts and at pH 8.5 and 25 degrees C. Whole-cell hydrolysates of strain JSM 073097(T) contained meso-diaminopimelic acid and no diagnostic sugars. The predominant menaquinones were MK-10(H(4)), MK-10(H(6)) and MK-10(H(8)). The major cellular fatty acids were iso-C(15 : 0), iso-C(16 : 0), anteiso-C(16 : 0) and 10-methyl C(18 : 0). Polar lipids comprised diphosphatidylglycerol, phosphatidylcholine and phosphatidylglycerol. The DNA G+C content of strain JSM 073097(T) was 70.4 mol%. The combination of phylogenetic analysis, DNA-DNA relatedness data, phenotypic characteristics and chemotaxonomic data supported the suggestion that strain JSM 073097(T) represents a novel species of the genus Nocardiopsis, for which the name Nocardiopsis litoralis sp. nov. is proposed. The type strain is JSM 073097(T) (=DSM 45168(T)=KCTC 19473(T)).

Nocardiopsis quinghaiensis sp. nov., isolated from saline soil in China

A previously unknown Gram-positive, obligately aerobic actinomycete, YIM 28A4(T), was isolated from a sample of saline soil collected from the Qaidam Basin in Qinghai Province, north-west China, and was investigated using a polyphasic taxonomic approach. The strain grew well on most of the media tested, producing white to pale-yellow substrate mycelium, white aerial mycelium and straight to flexuous hyphae. The substrate mycelium was well developed and fragmented with age; the aerial mycelium produced long, straight spore chains. The spore chains were composed of non-motile, smooth-surfaced, rod-shaped spores. No diffusible pigments were produced on any of the media tested. The strain grew in the presence of 0-10 % (w/v) NaCl and at pH 6.0-8.0, with optimum growth occurring at 3 % (w/v) NaCl and pH 7.0. It grew at 10-37 degrees C, the optimum growth temperature being 28 degrees C. Whole-cell hydrolysates of strain YIM 28A4(T) contained meso-diaminopimelic acid and no diagnostic sugars. The predominant phospholipids were phosphatidylcholine, phosphatidylglycerol and diphosphatidylglycerol. The predominant menaquinones were MK-10, MK-10(H(2)), MK-11 and MK-11(H(2)). The major cellular fatty acids were iso-C(16 : 0), anteiso-C(15 : 0) and anteiso-C(17 : 0). The DNA G+C content was 67.1 mol%. The morphological and chemotaxonomic characteristics of the isolate matched those described for Nocardiopsis species. A phylogenetic analysis based on 16S rRNA gene sequence comparisons confirmed that strain YIM 28A4(T) was a member of the genus Nocardiopsis and most closely related to the type strains Nocardiopsis aegyptia DSM 44442(T) and Nocardiopsis halotolerans DSM 44410(T), showing 98.1 and 97.8 % 16S rRNA gene sequence similarity, respectively. Strain YIM 28A4(T) can be differentiated from these type strains by using phenotypic, phylogenetic and DNA-DNA hybridization data. On the basis of the polyphasic evidence, strain YIM 28A4(T) represents a novel species of the genus Nocardiopsis, for which the name Nocardiopsis quinghaiensis sp. nov. is proposed. The type strain is YIM 28A4(T) (=DSM 44739(T) =CGMCC 4.3494(T)).

Five novel species of the genus Nocardiopsis isolated from hypersaline soils and emended description of Nocardiopsis salina Li et al. 2004

Five novel Nocardiopsis strains isolated from hypersaline soils in China were subjected to a polyphasic analysis to determine their taxonomic position. All of the novel isolates could grow on agar plates at NaCl concentrations of up to 18 % (w/v), with optimum growth at 5-8 %. The DNA G+C contents of the novel strains ranged from 67.9 to 73.2 mol%. The morphological and chemotaxonomic characteristics of the isolates matched those described for members of the genus Nocardiopsis. Based on their 16S rRNA gene sequence analysis, DNA-DNA hybridization values and phenotypic characteristics, including the composition of cell-wall amino acids and sugars, menaquinones, polar lipids and cellular fatty acids, the isolates are proposed as representing five novel species of the genus Nocardiopsis. The novel species are proposed as Nocardiopsis gilva sp. nov. [type strain YIM 90087T (=KCTC 19006T=CCTCC AA 2040012T=DSM 44841T)], Nocardiopsis rosea sp. nov. [type strain YIM 90094T (=KCTC 19007T=CCTCC AA 2040013T=DSM 44842T), Nocardiopsis rhodophaea sp. nov. [type strain YIM 90096T (=KCTC 19049T=CCTCC AA 2040014T=DSM 44843T), Nocardiopsis chromatogenes sp. nov. [type strain YIM 90109T (=KCTC 19008T=CCTCC AA 2040015T=DSM 44844T) and Nocardiopsis baichengensis sp. nov. [type strain YIM 90130T (=KCTC 19009T=CCTCC AA 2040016T=DSM 44845T). On the basis of the chemotaxonomic data, the description of the recently described species Nocardiopsis salina Li et al. 2004 is emended.

Nocardiopsis salina sp. nov., a novel halophilic actinomycete isolated from saline soil in China

A moderately halophilic actinomycete strain, designated YIM 90010T, was isolated from a soil sample collected from a hypersaline habitat in Xinjiang Province, China, and then investigated using a polyphasic taxonomic approach. The strain produced abundant aerial mycelia and fragmented substrate mycelia on most media tested; the optimum NaCl concentration for growth was 10 % (w/v) and the optimum growth temperature and pH were 28 degrees C and 7.2, respectively. Chemotaxonomically and phylogenetically, the strain was related to members of the genus Nocardiopsis. The isolate contained chemotaxonomic markers that were diagnostic for the genus Nocardiopsis, i.e. meso-diaminopimelic acid, no diagnostic sugars, and MK-10(H6), MK-10(H8) and MK-12 as the predominant menaquinones. The major fatty acids were iso- and anteiso-branched acids combined with tuberculostearic acid (Me C(18 : 0)), straight-chain saturated fatty acids and unsaturated fatty acids. The G + C content was 73.1 mol%. Phylogenetic analysis confirmed that strain YIM 90010T was a member of the genus Nocardiopsis and most closely related to Nocardiopsis kunsanensis (97.6 % similarity) and Nocardiopsis xinjiangensis (98.1 % similarity). It can be differentiated from these species by using phenotypic characteristics, phylogenetic analysis and DNA-DNA hybridization results. On the basis of the polyphasic evidence, a novel species, Nocardiopsis salina sp. nov., is proposed. The type strain of the species is YIM 90010T (= KCTC 19003T = CCTCC AA 204009T).

Nocardiopsis alkaliphila sp. nov., a novel alkaliphilic actinomycete isolated from desert soil in Egypt

An alkaliphilic actinomycete strain, designated YIM 80379T, was isolated from a soil sample collected from the eastern desert of Egypt and subjected to polyphasic taxonomy. The strain produced substrate and aerial mycelia on different media, with an optimum pH for growth of 9.5-10 and scarce or no growth at pH 7. Strain YIM 80379T contained meso-diaminopimelic acid, no diagnostic sugars, type PIII phospholipids and MK-10(H6) and MK-10(H8) as the predominant menaquinones. All of these characters assign isolate YIM 80379T consistently to the genus Nocardiopsis. This was confirmed by 16S rDNA analysis. It can be differentiated from all Nocardiopsis species with validly published names by phenotypic characteristics, phylogenetic analysis and DNA-DNA hybridization results. On the basis of polyphasic evidence, a novel species, Nocardiopsis alkaliphila sp. nov., is proposed. The type strain of the species is YIM 80379T (=CCTCC AA001031T=DSM 44657T).