Antibacterial toner exhibits bactericidal effect against Cutibacterium acnes via keratin and sebum plug penetration.

Cutibacterium acnes is an opportunistic pathogen recognized as a contributing factor to acne vulgaris. The accumulation of keratin and sebum plugs in hair follicles facilitates C. acnes proliferation, leading to inflammatory acne. Although numerous antimicrobial cosmetic products for acne-prone skin are available, their efficacy is commonly evaluated against planktonic cells of C. acnes. Limited research has assessed the antimicrobial effects on microorganisms within keratin and sebum plugs. This study investigates whether an antibacterial toner can penetrate keratin and sebum plugs, exhibiting bactericidal effects against C. acnes. Scanning electron microscopy and next-generation sequencing analysis of the keratin and sebum plug suggest that C. acnes proliferate within the plug, predominantly in a biofilm-like morphology. To clarify the potential bactericidal effect of the antibacterial toner against C. acnes inside keratin and sebum plugs, we immersed the plugs in the toner, stained them with LIVE/DEAD BacLight Bacterial Viability Kit to visualize microorganism viability, and observed them using confocal laser scanning microscopy. Results indicate that most microorganisms in the plugs were killed by the antibacterial toner. To quantitatively evaluate the bactericidal efficacy of the toner against C. acnes within keratin and sebum, we immersed an artificial plug with inoculated C. acnes type strain and an isolate collected from acne-prone skin into the toner and obtained viable cell counts. The number of the type strain and the isolate inside the artificial plug decreased by over 2.2 log and 1.2 log, respectively, showing that the antibacterial toner exhibits bactericidal effects against C. acnes via keratin and sebum plug penetration.

A New Pathway for Forming Acetate and Synthesizing ATP during Fermentation in Bacteria.

Many bacteria and other organisms carry out fermentations forming acetate. These fermentations have broad importance for foods, agriculture, and industry. They also are important for bacteria themselves because they often generate ATP. Here, we found a biochemical pathway for forming acetate and synthesizing ATP that was unknown in fermentative bacteria. We found that the bacterium Cutibacterium granulosum formed acetate during fermentation of glucose. It did not use phosphotransacetylase or acetate kinase, enzymes found in nearly all acetate-forming bacteria. Instead, it used a pathway involving two different enzymes. The first enzyme, succinyl coenzyme A (succinyl-CoA):acetate CoA-transferase (SCACT), forms acetate from acetyl-CoA. The second enzyme, succinyl-CoA synthetase (SCS), synthesizes ATP. We identified the genes encoding these enzymes, and they were homologs of SCACT and SCS genes found in other bacteria. The pathway resembles one described in eukaryotes, but it uses bacterial, not eukaryotic, gene homologs. To find other instances of the pathway, we analyzed sequences of all biochemically characterized homologs of SCACT and SCS (103 enzymes from 64 publications). Homologs with similar enzymatic activity had similar sequences, enabling a large-scale search for them in genomes. We searched nearly 600 genomes of bacteria known to form acetate, and we found that 6% encoded homologs with SCACT and SCS activity. This included >30 species belonging to 5 different phyla, showing that a diverse range of bacteria encode the SCACT/SCS pathway. This work suggests the SCACT/SCS pathway is important for acetate formation in many branches of the tree of life. IMPORTANCE Pathways for forming acetate during fermentation have been studied for over 80 years. In that time, several pathways in a range of organisms, from bacteria to animals, have been described. However, one pathway (involving succinyl-CoA:acetate CoA-transferase and succinyl-CoA synthetase) has not been reported in prokaryotes. Here, we discovered enzymes for this pathway in the fermentative bacterium Cutibacterium granulosum. We also found >30 other fermentative bacteria that encode this pathway, demonstrating that it could be common. This pathway represents a new way for bacteria to form acetate from acetyl-CoA and synthesize ATP via substrate-level phosphorylation. It could be a target for controlling yield of acetate during fermentation, with relevance for foods, agriculture, and industry.

Improving propionic acid production from a hemicellulosic hydrolysate of sorghum bagasse by means of cell immobilization and sequential batch operation.

Propionic acid (PA) is an important organic compound with extensive application in different industrial sectors and is currently produced by petrochemical processes. The production of PA by large-scale fermentation processes presents a bottleneck, particularly due to low volumetric productivity. In this context, the present work aimed to produce PA by a biochemical route from a hemicellulosic hydrolysate of sorghum bagasse using the strain Propionibacterium acidipropionici CIP 53164. Conditions were optimized to increase volumetric productivity and process efficiency. Initially, in simple batch fermentation, a final concentration of PA of 17.5 g⋅L-1 was obtained. Next, fed batch operation with free cells was adopted to minimize substrate inhibition. Although a higher concentration of PA was achieved (38.0 g⋅L-1 ), the response variables (YP/S = 0.409 g⋅g-1 and QP = 0.198 g⋅L-1 ⋅H-1 ) were close to those of the simple batch experiment. Finally, the fermentability of the hemicellulosic hydrolysate was investigated in a sequential batch with immobilized cells. The PA concentration achieved a maximum of 35.3 g⋅L-1 in the third cycle; moreover, the volumetric productivity was almost sixfold higher (1.17 g⋅L-1 ⋅H-1 ) in sequential batch than in simple batch fermentation. The results are highly promising, providing preliminary data for studies on scaling up the production of this organic acid.

Short chain fatty acids produced by Cutibacterium acnes inhibit biofilm formation by Staphylococcus epidermidis.

Biofilm formation by bacterial pathogens is associated with numerous human diseases and can confer resistance to both antibiotics and host defenses. Many strains of Staphylococcus epidermidis are capable of forming biofilms and are important human pathogens. Since S. epidermidis coexists with abundant Cutibacteria acnes on healthy human skin and does not typically form a biofilm in this environment, we hypothesized that C. acnes may influence biofilm formation of S. epidermidis. Culture supernatants from C. acnes and other species of Cutibacteria inhibited S. epidermidis but did not inhibit biofilms by Pseudomonas aeruginosa or Bacillus subtilis, and inhibited biofilms by S. aureus to a lesser extent. Biofilm inhibitory activity exhibited chemical properties of short chain fatty acids known to be produced from C. acnes. The addition of the pure short chain fatty acids propionic, isobutyric or isovaleric acid to S. epidermidis inhibited biofilm formation and, similarly to C. acnes supernatant, reduced polysaccharide synthesis by S. epidermidis. Both short chain fatty acids and C. acnes culture supernatant also increased sensitivity of S. epidermidis to antibiotic killing under biofilm-forming conditions. These observations suggest the presence of C. acnes in a diverse microbial community with S. epidermidis can be beneficial to the host and demonstrates that short chain fatty acids may be useful to limit formation of a biofilm by S. epidermidis.

Pathogenic genetic variations of C. acnes are associated with clinically relevant orthopedic shoulder infections.

Many surgeons continue to face the clinical dilemma of interpreting a positive aspiration or unexpected positive Cutibacterium acnes (C. acnes) culture. There are factors that complicate the interpretation of positive cultures including variations in both frequency of false positive cultures and virulence properties. As indices of virulence, hemolytic strains, from previously confirmed clinically infected shoulders, were compared with non-hemolytic isolates determined to be contaminants, by RNA-sequencing (RNA-Seq). Six C. acnes isolates from patients who underwent revision total shoulder arthroplasty (TSA) were identified based on previously described infection criteria. Three C. acnes isolates from each group underwent RNA-Seq. Differential gene expression analysis, principal component analysis (PCA), and heatmap analysis were used to determine the gene variation and patterning between the definite infection and probable contaminant isolates. Differential gene expression analysis identified genes that were differentially expressed between the isolates classified as definite infection and isolates classified as probable contaminants. PCA using a 500 gene subset of identified genes was able to find combinations of these genes that separated out the definite infection and probable contaminants isolates. The heatmap demonstrated similar gene expression in the three Definite Infections isolates, and significantly different expression when compared with the probable contaminant isolates. Clinical significance: C. acnes revision TSA isolates classified as definite infection and probable contaminant demonstrated a similar gene expression pattern to each respective group and different gene expression pattern when compared between groups. These findings indicate distinct differences in C. acnes strains associated with clinically relevant orthopedic TSA infections.

Porphyrin Production and Regulation in Cutaneous Propionibacteria.

Porphyrins are intermediate metabolites in the biosynthesis of vital molecules, including heme, cobalamin, and chlorophyll. Bacterial porphyrins are known to be proinflammatory, with high levels linked to inflammatory skin diseases. Propionibacterium species are dominant skin commensals and play essential roles in defending against pathogens and in triggering an inflammatory response. To better understand how the inflammatory potential of the skin microbiome may vary depending on its propionibacterial composition, we compared the production levels of porphyrins among Propionibacterium acnes, Propionibacterium granulosum, Propionibacterium avidum, and Propionibacterium humerusii strains. We found that porphyrin production varied among these species, with P. acnes type I strains producing significantly larger amounts of porphyrins than P. acnes type II and III strains and other Propionibacterium species. P. acnes strains that are highly associated with the common skin condition acne vulgaris responded to vitamin B12 supplementation with significantly higher porphyrin production. In contrast, vitamin B12 supplementation had no effect on the porphyrin production of health-associated P. acnes strains and other propionibacteria. We observed low-level porphyrin production in most Propionibacterium strains harboring the deoR repressor gene, with the exception of P. acnes strains belonging to type I clades IB-3 and IC. Our findings shed light on the proinflammatory potential of distinct phylogenetic lineages of P. acnes as well as other resident skin propionibacteria. We demonstrate that the overall species and strain composition is important in determining the metabolic output of the skin microbiome in health and disease.IMPORTANCE Porphyrins are a group of metabolites essential to the biosynthesis of heme, cobalamin, and chlorophyll in living organisms. Bacterial porphyrins can be proinflammatory, with high levels linked to human inflammatory diseases, including the common skin condition acne vulgaris. Propionibacteria are among the most abundant skin bacteria. Variations in propionibacteria composition on the skin may lead to different porphyrin levels and inflammatory potentials. This study characterized porphyrin production in all lineages of Propionibacterium acnes, the most dominant skin Propionibacterium, and other resident skin propionibacteria, including P. granulosum, P. avidum, and P. humerusii We revealed that P. acnes type I strains produced significantly more porphyrins than did type II and III strains and other Propionibacterium species. The findings from this study shed light on the proinflammatory potential of the skin microbiome and can be used to guide the development of effective acne treatments by modulating the skin microbiome and its metabolic activities.

Nisin J, a Novel Natural Nisin Variant, Is Produced by Staphylococcus capitis Sourced from the Human Skin Microbiota.

The skin microbiota is thought to play a key role in host protection from infection. Nisin J is a novel nisin variant produced by Staphylococcus capitis APC 2923, a strain isolated from the toe web space area in a screening study performed on the human skin microbiota. Whole-genome sequencing and mass spectrometry of the purified peptide confirmed that S. capitis APC 2923 produces a 3,458-Da bacteriocin, designated nisin J, which exhibited antimicrobial activity against a range of Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) and Cutibacterium acnes The gene order in the nisin J gene cluster (nsjFEGBTCJP) differs from that of other nisin variants in that it is lacking the nisin regulatory genes, nisRK, as well as the nisin immunity gene nisI Nisin J has 9 amino acid changes compared to prototypical nisin A, with 8 amino acid substitutions, 6 of which are not present in other nisin variants (Ile4Lys, Met17Gln, Gly18Thr, Asn20Phe, Met21Ala, Ile30Gly, Val33His, and Lys34Thr), and an extra amino acid close to the C terminus, rendering nisin J the only nisin variant to contain 35 amino acids. This is the first report of a nisin variant produced by a Staphylococcus species and the first nisin producer isolated from human skin.IMPORTANCE This study describes the characterization of nisin J, the first example of a natural nisin variant, produced by a human skin isolate of staphylococcal origin. Nisin J displays inhibitory activity against a wide range of bacterial targets, including MRSA. This work demonstrates the potential of human commensals as a source for novel antimicrobials that could form part of the solution to antibiotic resistance across a broad range of bacterial pathogens.

Cutibacterium avidum is phylogenetically diverse with a subpopulation being adapted to the infant gut.

The infant gut harbors a diverse microbial community consisting of several taxa whose persistence depends on adaptation to the ecosystem. In healthy breast-fed infants, the gut microbiota is dominated by Bifidobacterium spp.. Cutibacterium avidum is among the initial colonizers, however, the phylogenetic relationship of infant fecal isolates to isolates from other body sites, and C. avidum carbon utilization related to the infant gut ecosystem have been little investigated. In this study, we investigated the phylogenetic and phenotypic diversity of 28 C. avidum strains, including 16 strains isolated from feces of healthy infants. We investigated the in vitro capacity of C. avidum infant isolates to degrade and consume carbon sources present in the infant gut, and metabolic interactions of C. avidum with infant associated Bifidobacterium longum subsp. infantis and Bifidobacterium bifidum. Isolates of C. avidum showed genetic heterogeneity. C. avidum consumed d- and l-lactate, glycerol, glucose, galactose, N-acetyl-d-glucosamine and maltodextrins. Alpha-galactosidase- and ß-glucuronidase activity were a trait of a group of non-hemolytic strains, which were mostly isolated from infant feces. Beta-glucuronidase activity correlated with the ability to ferment glucuronic acid. Co-cultivation with B. infantis and B. bifidum enhanced C. avidum growth and production of propionate, confirming metabolic cross-feeding. This study highlights the phylogenetic and functional diversity of C. avidum, their role as secondary glycan degraders and propionate producers, and suggests adaptation of a subpopulation to the infant gut.

Short-Chain Fatty Acids from Cutibacterium acnes Activate Both a Canonical and Epigenetic Inflammatory Response in Human Sebocytes.

The regulation of cutaneous inflammatory processes is essential for the human skin to maintain homeostasis in the presence of the dense communities of resident microbes that normally populate this organ. Forming the hair follicle-associated sebaceous gland, sebocytes are specialized lipid-producing cells that can release inflammatory mediators. Cytokine and chemokine expression by pilosebaceous epithelial cells (i.e., sebocytes and follicular keratinocytes) has been proposed to contribute to the common human skin disease acne vulgaris. The underlying mechanisms that drive inflammatory gene expression in acne-involved pilosebaceous epithelial cells are still unknown because almost all sebaceous follicles contain dense concentrations of bacteria yet only some show an inflammatory reaction. In this study, we hypothesized that metabolites from the abundant skin-resident microbe Propionibacterium acnes can influence cytokine expression from human sebocytes. We show that short-chain fatty acids produced by P. acnes under environmental conditions that favor fermentation will drive inflammatory gene expression from sebocytes. These molecules are shown to influence sebocyte behavior through two distinct mechanisms: the inhibition of histone deacetylase (HDAC) activity and the activation of fatty acid receptors. Depletion of HDAC8 and HDAC9 in human sebocytes resulted in an enhanced cytokine response to TLR-2 activation that resembled the transcriptional profile of an acne lesion. These data provide a new insight into the regulation of inflammatory gene expression in the skin, further characterize the contribution of sebocytes to epidermal immunity, and demonstrate how changes in the metabolic state of the skin microbiome can promote inflammatory acne.

Integrated approach to enhance the anaerobic biodegradation of benz[α]anthracene: A high-molecule-weight polycyclic aromatic hydrocarbon in sludge by simultaneously improving the bioavailability and microbial activity.

The biodegradation of benz[α]anthracene (BaA), which was a high-molecule-weight PAH, was enhanced via a combination of alkaline and alkyl polyglucosides (APG) treatment during waste activated sludge (WAS) anaerobic fermentation. The biodegradation efficiency of BaA was increased from 14.1% in the control to 30.2 and 47.8% in pH 10 and pH 10 & APG reactors, respectively. Mechanism investigations found that the alkaline and APG treatments stimulated the processes of BaA desorption from sludge and transfer/entry into microorganisms, and ultimately improved the BaA bioavailability. Meanwhile, the huge released substrates from WAS not only served as carbon sources but also involved in the electron transfer among microorganisms which contributed to the BaA biodegradation process. Moreover, the microbial activities involved in BaA biodegradation, including the abundances of functional bacteria, activities of enzymes and quantities of genes, were also incremented due to the alkaline and APG treatments. Overall, the simultaneous improvement of BaA bioavailability and microbial activities enhanced its biodegradation efficiency.

Pseudopropionibacterium rubrum sp. nov., a novel red-pigmented species isolated from human gingival sulcus.

In this study, Strain [corrected] SK-1(T), a novel gram-positive, pleomorphic, rod-shaped, non-spore forming, non-motile organism, designated SK-1T , was isolated from human gingival sulcus and found to produce acetic acid, propionic acid, lactic acid, and succinic acid as end products of glucose fermentation. Strain SK-1T is most closely related to Pseudopropionibacterium (Propionibacterium) propionicum with sequence homologies of the 16S rRNA and RNA polymerase ß subunit (rpoB) genes of 96.6% and 93.1%, respectively. The genomic DNA G + C content of the isolate was 61.8 mol%. On the basis of the sequence data of the 16S rRNA and housekeeping (rpoB) genes, a novel taxon is here proposed, Pseudopropionibacterium rubrum sp. nov. (type strain SK-1T = JCM 31317T = DSM 100122T ). The 16S rRNA and rpoB gene sequences of strain SK-1T have been deposited in the DDBJ under the accession numbers LC002971 and LC102236, respectively.

Polyphosphate metabolic gene expression analyses reveal mechanisms of phosphorus accumulation and release in Microlunatus phosphovorus strain JN459.

The ability of Microlunatus phosphovorus to accumulate large amounts of polyphosphate (Poly-P) plays an important role in removing soluble phosphorus from wastewater. Strain JN459, isolated from a sewage system, was previously demonstrated to be Microlunatus phosphovorus. In this study, we analyzed the phosphorus-accumulating and phosphorus-releasing characteristics of strain JN459. Our analyses indicate that strain JN459 accumulates Poly-P under aerobic conditions but releases phosphorus under anaerobic conditions. To determine the mechanisms underlying Poly-P metabolism in strain JN459, we compared transcriptional profiles under aerobic and anaerobic conditions. Significant differences were detected in the expression levels of genes associated with Poly-P metabolism between aerobic and anaerobic conditions, including ppk (MLP_47700, MLP_50300 and MLP_05750), ppgk (MLP_05430 and MLP_26610), ppx (MLP_44770), pap (MLP_23310) and ppnk (MLP_17420). The high expression of polyphosphate glucokinase (MLP_05430) and polyphosphate/ATP-dependent NAD kinase (MLP_17420) indicated that both of them might be responsible for utilizing Poly-P as the energy resource for growth under anaerobic conditions. These findings enhance our understanding of phosphate metabolism in a major bacterial species involved in wastewater phosphorus reduction.

Dairy propionibacteria prevent the proliferative effect of plant lectins on SW480 cells and protect the metabolic activity of the intestinal microbiota in vitro.

Plant lectins are specific carbohydrate-binding proteins that are widespread in legumes such as beans and pulses, seeds, cereals, and many plants used as farm feeds. They are highly resistant to cooking and digestion, reaching the intestinal lumen and/or blood circulation with biological activity. Since many legume lectins trigger harmful local and systemic reactions after their binding to the mucosal surface, these molecules are generally considered anti-nutritive and/or toxic substances. In the gut, specific cell receptors and bacteria may interact with these dietary components, leading to changes in intestinal physiology. It has been proposed that probiotic microorganisms with suitable surface glycosidic moieties could bind to dietary lectins, favoring their elimination from the intestinal lumen or inhibiting their interaction with epithelial cells. In this work, we assessed in vitro the effects of two representative plant lectins, concanavalin A (Con A) and jacalin (AIL) on the proliferation of SW480 colonic adenocarcinoma cells and metabolic activity of colonic microbiota in the absence or presence of Propionibacterium acidipropionici CRL 1198. Both lectins induced proliferation of colonic cells in a dose-dependent manner, whereas ConA inhibited fermentative activities of colonic microbiota. Pre-incubation of propionibacteria with lectins prevented these effects, which could be ascribed to the binding of lectins by bacterial cells since P. acidipropionici CRL 1198 was unable to metabolize these proteins, and its adhesion to colonic cells was reduced after reaction with Con A or AIL. The results suggest that consumption of propionibacteria at the same time as lectins could reduce the incidence of lectin-induced alterations in the gut and may be a tool to protect intestinal physiology.

[Research progress on the genus Microlunatus].

Members of the genus Microlunatus exhibit many potential advantages in managing the environmental pollution caused by phosphorus. The genus was proposed by Nakamura and co-workers with the name Microlunatus phosphovorus as the type species in 1995. Up to date, the genus Microlunatus encompasses seven validly described species, which were isolated from various environments. Members of the genus Microlunatus share the following genus-specific characteristics, possessing LL-2, 6-diaminopimelic acid in the cell wall peptidoglycan, MK-9(H4) as the predominant menaquinone and diphosphatidylglycerol and phosphatidylglycerol as the phospholipid pattern. Based on the taxonomic results of two newly isolated strains of the genus Microlunatus and the related reference reports, this review summarizes the research advances of the genus Microlunatus, including the genus establishment, taxonomic characteristics, their distribution in the environments, as well as the application prospect in chemical and medical industry.

Tessaracoccus defluvii sp. nov., isolated from an aeration tank of a sewage treatment plant.

A Gram-positive, non-motile, aerobic, coccus-shaped bacterium, designated strain LNB-140T, was isolated from a sewage treatment plant in the Republic of Korea and was characterised using a polyphasic taxonomic approach. Comparative 16S rRNA gene sequence analysis showed that strain LNB-140T belongs to genus Tessaracoccus in the family Propionibacteriaceae of the phylum Actinobacteria. The 16S rRNA gene sequence similarities between strain LNB-140T and type strains of the genus, Tessaracoccus flavescens SST-39T and Tessaracoccus rhinocerotis YIM101269T are 97.8 and 97.4 %, respectively. The chemotaxonomic properties of strain LNB-140T are consistent with those of members of the genus Tessaracoccus: a quinone system with MK-9(H4) as the predominant menaquinone; anteiso-C15:0 and iso C15:0 as the predominant cellular fatty acids; and LL-2,6-diaminopimelic acid as the diagnostic peptidoglycan diamino acid. The major polar lipids were identified as diphosphatidylglycerol and phosphatidylethanolamine. The G+C content of the genomic DNA was determined to be 67.1 mol%. Differential phenotypic properties along with low DNA-DNA relatedness (<30 ± 3.2 %) with closely related type strains show that strain LNB-140T is distinct from previously described members of the genus Tessaracoccus and represents a novel species in this genus, for which the name Tessaracoccus defluvii sp. nov. is proposed. The type strain is LNB-140T (=KEMB 5401-076T = JCM 17540T).

Mumia xiangluensis sp. nov., isolated from the rhizosphere of Peucedanum praeruptorum Dunn.

During an investigation of microbial diversity in medicinal herbs, a novel actinobacterium, strain NEAU-KD1(T) was isolated from the rhizosphere of Peucedanum praeruptorum Dunn collected from Xianglu Mountain in Heilongjiang Province, northeast China and characterized using a polyphasic approach. The organism was found to have the typical chemotaxonomic and morphological characteristics of the genus Mumia. Cells were observed to be non-spore-forming and irregular cocci. The cell wall was found to contain LL-diaminopimelic acid as the cell wall diamino acid. The whole-cell sugars were detected as galactose and rhamnose and the predominant menaquinone was identified as MK-9(H4). The polar lipids were found to consist of diphosphatidylglycerol, phosphatidylglycerol, phosphoglycolipid and five unidentified phospholipids. The major cellular fatty acids were determined to be composed of C16:0, 10-methyl C18:0 and C18:1ω7c. The phylogenetic analysis based on 16S rRNA gene sequence also indicated that strain NEAU-KD1(T) belongs to the genus Mumia and with high sequence similarity to Mumia flava NBRC 109973(T) (97.6 % sequence similarity). The results of DNA-DNA hybridization and the phenotypic characteristics indicated that strain NEAU-KD1(T) could be distinguished from its close phylogenetic relative. Thus, strain NEAU-KD1(T) can be concluded to represent a novel species of the genus Mumia, for which the name Mumia xiangluensis sp. nov. is proposed. The type strain is NEAU-KD1(T) (=CGMCC 4.7305(T) = DSM 101040(T)).

Microlunatus cavernae sp. nov., a novel actinobacterium isolated from Alu ancient cave, Yunnan, South-West China.

A Gram-positive, coccoid, non-endospore-forming actinobacterium, designated YIM C01117(T), was isolated from a soil sample collected from Alu ancient cave, Yunnan province, south-west China. Based on the 16S rRNA gene sequence analysis, strain YIM C01117(T) was shown to belong to the genus Microlunatus, with highest sequence similarity of 97.4 % to Microlunatus soli DSM 21800(T). The whole genomic DNA relatedness as shown by the DNA-DNA hybridization study between YIM C01117(T) and M. soli DSM 21800(T) had a low value (47 ± 2 %). Strain YIM C01117(T) was determined to contain LL-diaminopimelic acid with Gly, Glu and Ala amino acids (A3γ' type) in the cell wall. Whole-cell hydrolysates were found to contain glucose, galactose, mannose and ribose. The major polar lipids were determined to be phosphatidylglycerol and diphosphatidylglycerol. The predominant menaquinone system present is MK-9(H4), while the major fatty acids were identified to be anteiso-C15:0 (24.1 %), iso-C16:0 (22.3 %) and iso-C15:0 (11.4 %). The G+C content of the genomic DNA was determined to be 65.9 mol%. The chemotaxonomic and genotypic data support the affiliation of the strain YIM C01117(T) to the genus Microlunatus. The results of physiological and biochemical tests allow strain YIM C01117(T) to be differentiated phenotypically from recognized Microlunatus species. Strain YIM C01117(T) is therefore considered to represent a novel species of the genus Microlunatus, for which the name Microlunatus cavernae sp. nov. is proposed. The type strain is YIM C01117(T) (= DSM 26248(T) = JCM 18536(T)).

Nocardioides panaciterrulae sp. nov., isolated from soil of a ginseng field, with ginsenoside converting activity.

A Gram-positive, coccoid to rod-shaped, non-spore-forming bacterium, designated Gsoil 958(T), was isolated from soil of a ginseng field located in Pocheon province in South Korea. This bacterium was characterized in order to determine its taxonomic position by using a polyphasic approach. Strain Gsoil 958(T) was observed to grow well at 25-30 °C and at pH 7.0 on R2A and nutrient agar without NaCl supplementation. Strain Gsoil 958(T) was determined to have ß-glucosidase activity and the ability to transform ginsenoside Rb1 (one of the dominant active components of ginseng) to F2 via gypenoside XVII and Rd. On the basis of 16S rRNA gene sequence similarity, strain Gsoil 958(T) was shown to belong to the family Nocardioidaceae and related most closely to Nocardioides koreensis MSL-09(T) (97.6 % 16S rRNA gene sequence similarity), Nocardioides aquiterrae GW-9(T) (97.0 %), and Nocardioides sediminis MSL-01(T) (97.0 %). The sequence similarities with other validly named species within the genus Nocardioides were less than 96.8 %. Strain Gsoil 958(T) was characterized chemotaxonomically as having LL-2,6-diaminopimelic acid in the cell-wall peptidoglycan, MK-8(H4) as the predominant menaquinone, and iso-C16:0, iso-C16:1 H, iso-C14:0, iso-C15:0 were identified as the major fatty acids. The G + C content of genomic DNA was determined to be 70.8 mol %. The chemotaxonomic properties and phenotypic characteristics supported the affiliation of strain Gsoil 958(T) to the genus Nocardioides. The results of both physiological and biochemical tests allowed for differentiation of strain Gsoil 958(T) from the recognized Nocardioides species. Therefore, strain Gsoil 958(T) is considered to represent a novel species of the genus Nocardioides, for which the name Nocardioides panaciterrulae sp. nov. is proposed, with the type strain Gsoil 958(T) (KACC 14271(T) = KCTC 19471(T) = DSM 21350(T)).

Deciphering the genome of polyphosphate accumulating actinobacterium Microlunatus phosphovorus.

Polyphosphate accumulating organisms (PAOs) belong mostly to Proteobacteria and Actinobacteria and are quite divergent. Under aerobic conditions, they accumulate intracellular polyphosphate (polyP), while they typically synthesize polyhydroxyalkanoates (PHAs) under anaerobic conditions. Many ecological, physiological, and genomic analyses have been performed with proteobacterial PAOs, but few with actinobacterial PAOs. In this study, the whole genome sequence of an actinobacterial PAO, Microlunatus phosphovorus NM-1(T) (NBRC 101784(T)), was determined. The number of genes for polyP metabolism was greater in M. phosphovorus than in other actinobacteria; it possesses genes for four polyP kinases (ppks), two polyP-dependent glucokinases (ppgks), and three phosphate transporters (pits). In contrast, it harbours only a single ppx gene for exopolyphosphatase, although two copies of ppx are generally present in other actinobacteria. Furthermore, M. phosphovorus lacks the phaABC genes for PHA synthesis and the actP gene encoding an acetate/H(+) symporter, both of which play crucial roles in anaerobic PHA accumulation in proteobacterial PAOs. Thus, while the general features of M. phosphovorus regarding aerobic polyP accumulation are similar to those of proteobacterial PAOs, its anaerobic polyP use and PHA synthesis appear to be different.

Salinarimonas ramus sp. nov. and Tessaracoccus oleiagri sp. nov., isolated from a crude oil-contaminated saline soil.

Four bacterial strains, SL014B-41A4(T), SL014B-20A1(T), SL014B-76A1 and SL014B-79A, isolated from a crude oil-contaminated saline soil of Shengli Oilfield, China, were investigated using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain SL014B-41A4(T) belonged to the genus Salinarimonas in the order Rhizobiales, with the highest sequence similarity with Salinarimonas rosea YIM YD3(T) (98.3 %). The DNA-DNA relatedness of strain SL014B-41A4(T) to S. rosea YIM YD3(T) was 27.03 ± 3.0 %. Strain SL014B-41A4(T) was Gram-negative staining, facultatively anaerobic and produced deep red pigment in artificial seawater medium. Cells of strain SL014B-41A4(T) were rod-shaped (0.6-4.0 × 1.25-25 µm), motile with a single polar flagellum and often formed branches. The strain contained Q-10 as the predominant respiratory ubiquinone and C(18 : 1)ω7c (57.5 %), C(16 : 0) (16.4 %) and 10-methyl C(19 : 0) (9.1 %) as the major fatty acids. Strains SL014B-20A1(T), SL014B-76A1 and SL014B-79A were actinobacteria and belonged to the genus Tessaracoccus in the family Propionibacteriaceae of the order Actinomycetales with the highest 16S rRNA gene sequence similarities with Tessaracoccus flavescens SST-39(T) (96.4 %), Tessaracoccus lubricantis KISS-17Se(T) (96.2 %) and Tessaracoccus bendigoensis Ben 106(T) (94.7 %). Strains SL014B-20A1(T), SL014B-76A1 and SL014B-79A were Gram-positive staining, facultatively anaerobic, non-endospore-forming, non-motile, acid-fast and oval to rod-shaped (0.48 × 0.5-1.0 µm). These three novel strains had ll-diaminopimelic acid (DAP) as the diagnostic diamino acid in the cell-wall peptidoglycan, MK-9(H(4)) as the only menaquinone and anteiso-C(15 : 0) (67.11-76.14 %) as the major cellular fatty acid. The G+C contents of the genomic DNA of strain SL014B-41A4(T) and strains SL014B-20A1(T), SL014B-76A1 and SL014B-79A were 67.68 mol% and 65.65-67.17 mol%, respectively. Based on phenotypic and genotypic characteristics, strain SL014B-41A4(T) represents a novel species of the genus Salinarimonas, for which the name Salinarimonas ramus is proposed, with strain SL014B-41A4(T) ( = DSM 22962(T) = CGMCC 1.9161(T)) as the type strain. Strains SL014B-20A1(T), SL014B-76A1 and SL014B-79A represent a novel species of the genus Tessaracoccus, for which the name Tessaracoccus oleiagri is proposed, with strain SL014B-20A1(T) ( = DSM 22955(T) = CGMCC 1.9159(T)) as the type strain.