Natrinema salsiterrestre sp. nov., an extremely halophilic archaeon isolated from a hypersaline soil.

An extremely halophilic archaeal strain, designated S1CR25-10T, was isolated from hypersaline soil sampled in the Odiel Saltmarshes Natural Area in Southwestern Spain (Huelva) and subjected to a polyphasic taxonomic characterization. The cells were Gram-stain-negative, motile and their colonies were pink-pigmented. It was a strictly aerobic haloarchaeon that could grow at 25-55 °C (optimum, 37 °C), at pH 6.0-9.0 (optimum, pH 7.0-8.0) and in the presence of 12-30 % (w/v) total salts (optimum, 20-25 %, w/v). The phylogenetic analysis based on the comparison of the 16S rRNA gene sequences revealed that strain S1CR25-10T belongs to the genus Natrinema, with 98.9 % similarity to Natrinema salinisoli SLN56T. In addition, the values of orthologous average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity were below the threshold limits accepted for prokaryotic species delineation, with N. salinisoli SLN56T showing the highest relatedness values (92.6 % and 48.4 %, respectively). The major polar lipids were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and a glycolipid chromatographically identical to sulfated diglycosyl diether. The DNA G+C content of the isolate was 63.8 mol%. Based on the phylogenetic, phenotypic and chemotaxonomic characterization and the whole genome results, strain S1CR25-10T represents a new species within the genus Natrinema, for which the name Natrinema salsiterrestre sp. nov., with type strain S1CR25-10T (=CECT 30623T=CCM 9251T), is proposed.

Quantitative Analysis of Polyphosphoinositide, Bis(monoacylglycero)phosphate, and Phosphatidylglycerol Species by Shotgun Lipidomics After Methylation.

Phospholipids play important roles in biological process even at a very low level. For example, bis(monoacylglycerol)phosphate (BMP) is involved in the pathogenesis of lysosomal storage diseases, and polyphosphoinositides (PPI) play critical roles in cellular signaling and functions. Phosphatidylglycerol (PG), a structural isomer of BMP, mediates lipid-protein and lipid-lipid interactions, and inhibits platelet activating factor and phosphatidylcholine transferring. However, due to their low abundance, the analysis of these phospholipids from biological samples is technically challenging. Therefore, the cellular function and metabolism of these phospholipids are still elusive. This chapter overviews a novel method of shotgun lipidomics after methylation with trimethylsilyl-diazomethane (TMS-D) for accurate and comprehensive analysis of these phospholipid species in biological samples. Firstly, a modified Bligh and Dyer procedure is performed to extract tissue lipids for PPI analysis, whereas modified methyl-tert-butylether (MTBE) extraction and modified Folch extraction methods are described to extract tissue lipids for PPI analysis. Secondly, TMS-D methylation is performed to derivatize PG/BMP and PPI, respectively. Then, we described the shotgun lipidomics strategies that can be used as cost-effective and relatively high-throughput methods to determine BMP, PG, and PPI species and isomers with different phosphate position(s) and fatty acyl chains. The described method of shotgun lipidomics after methylation achieves feasible and reliable quantitative analysis of low-abundance lipid classes. The application of this novel method should enable us to reveal the metabolism and functions of these phospholipids in healthy and disease states.

Neptunomonas marina sp. nov., isolated from seawater.

Strain HPM-16T, isolated from seawater, was characterized using a polyphasic taxonomy approach. Phylogenetic analyses based on 16S rRNA gene sequences and coding sequences of an up-to-date bacterial core gene set (92 protein clusters) indicated that strain HPM-16T formed a phylogenetic lineage in the genus Neptunomonas. Strain HPM-16T was most closely related to Neptunomonas concharum LHW37T with 16S rRNA gene sequence similarity of 96.7%. Cells were Gram-stain negative, facultatively anaerobic, motile by means of a single polar flagellum, rod-shaped and formed white colonies. Optimal growth occurred at 30-35 °C, pH 6.5-8, and in the presence of 2-5% NaCl. C18:1ω7c and summed feature 3 (C16:1ω7c and/or C16:1ω6c) were the predominant fatty acids. The only isoprenoid quinone was Q-8. The polar lipid profile revealed the presence of phosphatidylethanolamine, phosphatidylglycerol and several uncharacterized lipids. The major polyamines were putrescine and spermidine. The draft genome was approximately 3.68 Mb in size with a G + C content of 50.5 mol%. Differential phenotypic properties, together with the phylogenetic inference, demonstrate that strain HPM-16T should be classified as a novel species of the genus Neptunomonas, for which the name Neptunomonas marina sp. nov. is presented. The type strain is HPM-16T (= BCRC 80980T = LMG 29560T = KCTC 52235T).

Simultaneous Relative Quantification of Various Polyglycerophospholipids with Isotope-Labeled Methylation by Nanoflow Ultrahigh Performance Liquid Chromatography-Tandem Mass Spectrometry.

Herein, we introduce a comprehensive analytical method for the separation and relative quantification of polyglycerophospholipids (PGPLs), including phosphatidylglycerol (PG), bis(monoacylglycero)phosphate (BMP), bis(diacylglycero)phosphate (BDP), Hemi BDP, cardiolipin (CL), monolysocardiolipin (MLCL), and dilysocardiolipin (DLCL), using isotope-labeled methylation (ILM) with nanoflow ultrahigh performance liquid chromatography-electrospray ionization-tandem mass spectrometry (nUHPLC-ESI-MS/MS). Abnormal levels of BMP and CL have been associated with the pathology of lysosomal storage and neurodegenerative diseases. Thus, simultaneous analysis of all PGPLs is important to understand the mechanisms and pathologies of such diseases. In this study, improved separation and MS detection of PGPLs, including their regioisomers, was achieved by the methylation of PGPL. ILM-based relative quantification was applied to lipid extracts from a dopaminergic cell line (SH-SY5Y) treated with drugs commonly used for Parkinson's disease (PD), resulting in the identification of 229 unique PGPLs, including 121 CLs, 71 MLCLs, and 16 Hemi BDP species. The drug treatment induced significant increases in the amount of CLs containing polyunsaturated fatty acyl chains, including 20:4 and 22:6, as well as decreased levels of BMP, Hemi BDP, and BDP species, demonstrating the feasibility of using ILM for the comprehensive and high-speed relative quantification of PGPLs.

Follicular dynamics of glycerophospholipid and sphingolipid metabolisms in polycystic ovary syndrome patients.

Polycystic ovary syndrome (PCOS) is a common heterogeneous disease, affecting up to 5-10% women at reproductive age. Although PCOS patients could produce morphologically normal metaphase II oocytes undergoing assisted reproductive techniques (ART), oocyte developmental competence and embryo development have been impaired in following in-vitro fertilization (IVF) steps. Follicular fluid (FF) provides a variety of information in oocyte environment when oocytes grow. In the present work, based on ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS), the metabolic signatures of PCOS FF have been compared with healthy women using untargeted metabolomics approach. Significant abundance differences of a series of glycerolipid, glycerophospholipids, sphingolipids, and carboxylic acids have been discovered. Among them, reduced levels of phosphatidylglycerolphosphate (PGP) and a triglyceride (TG) were highly related to the lower fertilization rate in PCOS; increased abundance of lysoPE and decreased amount of PC were significantly correlated with LH/FSH (ratio of luteinizing hormone to follicle stimulating hormone). Some metabolites, including decreased sphingolipids, glycerophospholipids, and fluctuated fatty acyls, also performed close relationship with other ART and clinical results. We concluded that dysfunctions in the metabolism of glycerolipid, glycerophospholipid, sphingolipid, and glycosphingolipid biosynthesis in PCOS patients' follicles play a non-ignorable role in declining the 2 pronuclei (PN) fertilization rate during IVF procedure.

Paraburkholderia dokdonella sp. nov., isolated from a plant from the genus Campanula.

The novel Gram-stain-negative, rod-shaped, aerobic bacterial strain DCR-13T was isolated from a native plant belonging to the genus Campanula on Dokdo, an island in the Republic of Korea. Comparative analysis of the 16S rRNA gene sequence indicated that this strain is closely related to Paraburkholderia peleae PP52-1T (98.43% 16S rRNA gene sequence similarity), Paraburkholderia oxyphila NBRC 105797T (98.42%), Paraburkholderia sacchari IPT 101T (98.28%), Paraburkholderia mimosarum NBRC 106338T (97.80%), Paraburkholderia denitrificans KIS30-44T (97.46%), and Paraburkholderia paradise WAT (97.45%). This analysis of the 16S rRNA gene sequence also suggested that DCR-13T and the six closely related strains formed a clade within the genus Paraburkholderia, but that DCR-13T was clearly separated from the established species. DCR-13T had ubiquinone 8 as its predominant respiratory quinone, and its genomic DNA G + C content was 63.9 mol%. The isolated strain grew at a pH of 6.0-8.0 (with an optimal pH of 6.5), 0-4% w/v NaCl (with an optimal level of 0%), and a temperature of 18-42°C (with an optimal temperature of 30°C). The predominant fatty acids were C16:0, summed feature 8 (C18:1ω7c/C18:1ω6c), C17:0 cyclo, C19:0 cyclo ω8c, summed feature 3 (C16:1ω6c/C16:1ω7c) and summed feature 2 (C12:0 aldehyde), and the major polar lipids were phosphatidylglycerol and phosphatidylethanolamine. On the basis of polyphasic evidence, it is proposed that strain DCR-13T (= KCTC 62811T = LMG 30889T) represents the type strain of a novel species, Paraburkholderia dokdonella sp. nov.

Brevibacterium anseongense sp. nov., isolated from soil of ginseng field.

Gram-positive, aerobic, non-motile, pale-yellow, and rodshaped bacterium, designated as Gsoil 188T, was isolated from the soil of a ginseng field in Pocheon, South Korea. A phylogenetic analysis based on 16S rRNA gene sequence comparison revealed that the strain formed a distinct lineage within the genus Brevibacterium and was most closely related to B. epidermidis NBRC 14811T (98.4%), B. sediminis FXJ8.269T (98.2%), B. avium NCFB 3055T (98.1%), and B. oceani BBH7T (98.1%), while it shared less than 98.1% identity with the other species of this genus. The DNA G + C content was 68.1 mol%. The predominant quinone was MK-8(H2). The major fatty acids were anteiso-C15:0 and anteiso-C17:0. The cell wall peptidoglycan of strain Gsoil 188T contained meso-diaminopimelic acid. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, and an unidentified aminolipid. The physiological and biochemical characteristics, low DNA-DNA relatedness values, and taxonomic analysis allowed the differentiation of strain Gsoil 188T from the other recognized species of the genus Brevibacterium. Therefore, strain Gsoil 188T represents a novel species of the genus Brevibacterium, for which the name Brevibacterium anseongense sp. nov. is proposed, with the type strain Gsoil 188T (= KACC 19439T = LMG 30331T).

Thalassorhabdus alkalitolerans gen. nov., sp. nov., a novel Bacillaceae member isolated from marine sediment.

A novel Gram-stain-variable, rod-shaped, non-motile and non-endospore-forming bacterium (strain G27T) was isolated from near Dhuvaran, Gujarat, India. Based on 16S rRNA gene sequence analysis, strain G27T was identified as a member of the class Firmibacteria and was most closely related to Bacillus populi FJAT-45347T (94.9 % sequence similarity), Salipaludibacillus aurantiacus S9T (94.9 %), Salipaludibacillus neizhouensis KCTC 13187T (94.7 %), Alteribacillus iranensis DSM 23995T (94.6 %) and other Firmibacteria (<94.6 %). The DNA G+C content of strain G27T was 43.4±0.6 mol%. The cell-wall peptidoglycan contained meso-diaminopimelic acid. Polar lipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid and five unidentified lipids. The predominant isoprenoid quinone was menaquinone MK-7. Major fatty acids (>5 %) included anteiso-C15:0, iso-C15 : 0, anteiso-C17:0, C16 : 0 and iso-C16 : 0. The results of phylogenetic, chemotaxonomic and biochemical tests allowed the clear differentiation of strain G27T from all other members of the family Bacillaceae.It is therefore considered to represent a novel species of a new genus, for which the name Thalassorhabdus alkalitolerans gen. nov., sp. nov., is proposed. The type strain of Thalassorhabdus alkalitolerans is G27T (=MCC 3411T=CGMCC 1.15772T=KCTC 33941T).

Zhongshania ponticola sp. nov., a novel lipolytic bacterium of the class Gammaproteobacteria isolated from seawater.

A bacterial strain, designated GM-8T, which was isolated from seawater around Pohang in Republic of Korea, was subjected to a polyphasic taxonomic study. It was lipolytic, Gram-stain-negative, aerobic, non-motile and coccoid, ovoid, or rod-shaped. Strain GM-8T grew optimally at 30 °C and in the presence of 2.0-3.0% (w/v) NaCl. The phylogenetic trees of 16S rRNA gene sequences based on three algorithms showed that strain GM-8T joined the clade comprising the type strains of Zhongshania species. The novel strain exhibited the highest 16S rRNA gene sequence similarity value (98.6%) to Zhongshania borealis CL-AS9T and sequence similarities of 97.7-98.3% to the type strains of three other Zhongshania species. Strain GM-8T contained Q-8 as the predominant ubiquinone and C17:1 ω8c, summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), and C18:1 ω7c as the major fatty acids. Phosphatidylglycerol and phosphatidylethanolamine were major polar lipids found in strain GM-8T and the type strain of Zhongshania antarctica. The DNA G + C content of strain GM-8T was 50.9 mol%. Mean DNA-DNA relatedness values between strain GM-8T and the type strains of four other Zhongshania species were 13.3-20.3%. Its differential phenotypic traits, together with the phylogenetic and genetic evidences, revealed that strain GM-8T is distinct from recognized species of the genus Zhongshania. On the basis of the data presented, strain GM-8T represents a novel species of the genus Zhongshania, for which the name Zhongshania ponticola sp. nov. is proposed. The type strain is GM-8T (= KCTC 62425T = KACC 19616T = NBRC 113193T).

Pseudoruegeria litorisediminis sp. nov., a novel lipolytic bacterium of the family Rhodobacteraceae isolated from a tidal flat.

A lipolytic bacterial strain, designated BPTF-M5T, was isolated from a tidal flat sediment of the Yellow Sea in Republic of Korea, and identified by a polyphasic taxonomic approach. It was Gram negative, aerobic, non-motile and rod shaped. Strain BPTF-M5T grew optimally at 30 °C and in the presence of 2.0-3.0% (w/v) NaCl. A neighbour-joining phylogenetic tree of 16S rRNA gene sequences showed that strain BPTF-M5T fell within the clade comprising the type strains of Pseudoruegeria species. The novel strain exhibited the highest 16S rRNA gene sequence similarity value (98.6%) to Pseudoruegeria marinistellae SF-16T. Strain BPTF-M5T exhibited sequence similarities of 97.0-98.5% to the type strains of five other Pseudoruegeria species and of less than 96.1% to other recognized species. Strain BPTF-M5T contained Q-10 as the predominant ubiquinone and C18:1 ω7c as the major fatty acid. Phosphatidylglycerol, one unidentified aminolipid, one unidentified lipid and one unidentified glycolipid were detected as major polar lipids in the novel strain. The DNA G + C content of strain BPTF-M5T was 63.3 mol%. DNA-DNA relatedness values between strain BPTF-M5T and the type strains of the six Pseudoruegeria species were 11.0-24.3%. The phenotypic properties of strain BPTF-M5T were clearly distinguished from those of the type strains of the six Pseudoruegeria species. Based on the polyphasic data presented, strain BPTF-M5T represents a novel species of the genus Pseudoruegeria, for which the name Pseudoruegeria litorisediminis sp. nov. is proposed. The type strain is BPTF-M5T (= KCTC 62420T = KACC 19613T = NBRC 113189T).

Nocardia zhihengii sp. nov., an actinobacterium isolated from rhizosphere soil of Psammosilene tunicoides.

A Nocardia-like actinobacterial strain, designated YIM TG2190T, was isolated from rhizosphere soil of Psammosilene tunicoides collected from Gejiu, Yunnan province, China. The cells of strain YIM TG2190T were observed to be Gram-stain positive and non-motile. The strain forms extensively branched substrate mycelia that fragments into rod-shaped elements. The 16S rRNA gene sequence analysis showed that strain YIM TG2190T is closely related to Nocardia nova (97.5%), Nocardia jiangxiensis (97.1%) and Nocardia miyunensis (96.8%). Growth occurs at 4-30 °C (optimum 28 °C), pH 6.0-8.0 (optimum pH 7.0) and the strain can tolerate NaCl (w/v) up to 3% (optimum 0-1%). The cell walls were found to contain meso-diaminopimelic acid. The whole-cell sugars were identified as glucose, mannose, ribose, galactose, arabinose and fucose. The polar lipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannosides, phosphatidylglycerol and an unidentified phospholipid. The menaquinones detected were MK-9 (H2) and MK-8 (H4). The major fatty acids (> 5%) were found to be C16:0 (33.9%), summed feature 3 (21.7%), C18:0 10-methyl TBSA (13.7%) and C18:1ω9c (7.0%). The DNA G+C content was determined to be 61.1 mol%. DNA-DNA relatedness between the strain YIM TG2190T and N. nova CGMCC 4.1705T, N. jiangxiensis CGMCC 4.1905T and N. miyunensis CGMCC 4.1904T were 46.9 ± 2.6, 36.8 ± 1.3, and 35.7 ± 2.6%, respectively, values which are less than the threshold value (70%) for the delineation of prokaryotic genomic species. The phenotypic, chemotaxonomic and phylogenetic data indicates that strain YIM TG2190T represents a novel species of the genus Nocardia, for which the name Nocardia zhihengii sp. nov. is proposed. The type strain is YIM TG2190T (=KCTC 39596T = DSM 100515T).

Terrabacter ginsengisoli sp. nov., isolated from ginseng cultivating soil.

A Gram-positive, strictly aerobic, nonmotile, yellowish, coccus-rod-shaped bacterium (designated Gsoil 653T) isolated from ginseng cultivating soil was characterized using a polyphasic approach to clarify its taxonomic position. The strain Gsoil 653T exhibited optimal growth at pH 7.0 on R2A agar medium at 30°C. Phylogenetic analysis based on 16S rRNA gene sequence similarities, indicated that Gsoil 653T belongs to the genus Terrabacter of the family Humibacillus, and was closely related to Terrabacter tumescens DSM 20308T (98.9%), Terrabacter carboxydivorans PY2T (98.9%), Terrabacter terrigena ON10T (98.8%), Terrabacter terrae PPLBT (98.6%), and Terrabacter lapilli LR-26T (98.6%). The DNA G + C content was 70.5 mol%. The major quinone was MK-8(H4). The primary polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidyl-ethanolamine. The predominant fatty acids were iso-C15:0, iso-C16:0, iso-C14:0, and anteiso-C15:0, as in the case of genus Terrabacter, thereby supporting the categorization of strain Gsoil 653T. However, the DNA-DNA relatedness between Gsoil 653T and closely related strains of Terrabacter species was low at less than 31%. Moreover, strain Gsoil 653T could be both genotypically and phenotypically distinguished from the recognized species of the genus Terrabacter. This isolate, therefore, represents a novel species, for which the name Terrabacter ginsengisoli sp. nov. is proposed with the type strain Gsoil 653T (= KACC 19444T = LMG 30325T).

Kribbella sindirgiensis sp. nov. isolated from soil.

A Kribbella strain FSN23T was isolated from soil sample which was collected from Caygoren Dam lakeside located in Sindirgi, Turkey. The isolate was investigated using a polyphasic approach consisting of numeric, chemotaxonomic and molecular analysis. The isolate indicated chemotaxonomic, morphological and phylogenetic properties associated with members of the genus Kribbella. Phylogenetic analysis based on the 16S rRNA sequence of the strain demonstrated that the strain forms a subclade with K. aluminosa HKI 0478T and K. jejuensis HD9T. The organism formed an extensively branched substrate and aerial hyphae which generated spiral chains of spores with smooth surfaces. The cell wall contained LL-diaminopimelic acid, and the whole cell sugars were glucose and ribose along with trace amounts of mannose. The polar lipids were identified as phosphatidylglycerol, diphosphatidylglycerol, four unidentified lipids and five unidentified polar lipids. The predominant menaquinone was MK-9(H4). The major cellular fatty acids were anteiso-C15:0 and iso-C16:0. Polyphasic taxonomy properties confirm that strain FSN23T represents a novel Kribbella taxon distinguished from closely related type strains. Hence, strain FSN23T (=KCTC 29220T = DSM 27082T) is proposed as the type strain of a novel species with the name Kribbella sindirgiensis sp. nov.

Albimonas pacifica sp. nov., isolated from seawater of the Pacific, and emended description of the genus Albimonas.

A Gram-stain-negative, aerobic, catalase- and oxidase-positive, non-flagellated, rod-shaped bacterium, designated strain P-50-3(T), was isolated from seawater of the Pacific. The strain grew at 10-40 °C (optimum at 30 °C) and with 0-12 % (w/v, optimum 2 %) NaCl. It reduced nitrate to nitrite but did not hydrolyse gelatin, starch or Tween 80. Analysis of 16S rRNA gene sequences showed that strain P-50-3(T) clustered tightly with the genus Albimonas and shared the highest 16S rRNA gene sequence similarity (94.3 %) with the type strain of Albimonas donghaensis. The major respiratory quinone was Q-10 and the major cellular fatty acids were C18 : 1ω7c, C18 : 0, 11-methyl C18 : 1ω7c and C16 : 0. Polar lipids included phosphatidylglycerol (PG), phosphatidylcholine (PC), two unidentified aminolipids and an unidentified lipid. The genomic DNA G+C content of strain P-50-3(T) was 69.0 mol%. On the basis of the data obtained in this polyphasic study, strain P-50-3(T) represents a novel species within the genus Albimonas, for which the name Albimonas pacifica sp. nov. is proposed. The type strain of Albimonas pacifica is P-50-3(T) ( = KACC 16527(T) = CGMCC 1.11030(T)). An emended description of the genus Albimonas Lim et al. 2008 is also proposed.

Role of molecular architecture on the relative efficacy of aurein 2.5 and modelin 5.

In order to gain an insight into the mechanism of antimicrobial peptide action, aurein 2.5 and modelin-5 were studied. When tested against Staphylococcus aureus, aurein 2.5 showed approximately 5-fold greater efficacy even though the higher net positive charge and higher helix stability shown by modelin-5 would have predicated modelin-5 to be the more effective antimicrobial. However, in the presence of S. aureus membrane mimics, aurein 2.5 showed greater helical content (75% helical) relative to modelin-5 (51% helical) indicative of increase in membrane association. This was supported by monolayer data showing that aurein 2.5 (6.6mNm(-1)) generated greater pressure changes than modelin-5 (5.3mNm(-1)). Peptide monolayers indicted that modelin-5 formed a helix horizontal to the plane of an asymmetric interface which would be supported by the even distribution of charge and hydrophobicity along the helical long axis and facilitate lysis by non-specific membrane binding. In contrast, a groove structure observed on the surface of aurein 2.5 was predicted to be the cause of enhanced lipid binding (K(d)=75µM) relative to modelin-5 (K(d)=118µM) and the balance of hydrophobicity along the aurein 2.5 long axis supported deep penetration into the membrane in a tilt formation. This oblique orientation generates greater lytic efficacy in high anionic lipid (71%) compared to modelin-5 (32%).

Simultaneous measurement of phosphatidylglycerol and disaturated-phosphatidylcholine palmitate kinetics from alveolar surfactant. Study in infants with stable isotope tracer, coupled with isotope ratio mass spectrometry.

Disaturated-phosphatidylcholine (DSPC) and phosphatidylglycerol (PG) are respectively the first and the third most abundant phospholipid in human alveolar surfactant. Their concentration decreases in airway surfactant of adults and infants with respiratory distress syndrome and cystic fibrosis. In this study, we used mass spectrometry (IRMS) to investigate the turnover of DSPC and PG in tracheal aspirates (TA) obtained from infants with normal or diseased lungs. We studied eight infants requiring mechanical ventilation: two with no lung disease, four with diaphragmatic hernia, one with ATP-binding cassette sub-family A member 3 heterozygote mutation and one with sepsis. Patients received deuterated water for 48 h as metabolic precursors of palmitate-DSPC and palmitate-PG. Serial TAs were obtained every 6 h for five days or until extubation. DSPC and PG were isolated from TA by column and high-performance thin layer chromatography. Deuterium enrichments of palmitate-DSPC and PG residues were measured by IRMS coupled with a gas chromatographer. Median secretion time (ST), peak time (PT) and fractional synthesis rate (FSR) were 3.7 [0.9- 13.4] h, 71.0 [52.2 - 85.2] h and 6.6 [6.3 - 11.1] %/day for DSPC and 19.3 [6.4 - 22.8] h, 49.0 [33.0 - 52.5] h and 5.8 [4.8 - 10.9] %/day for PG. This study shows that it is feasible to use deuterium derived from body water to trace simultaneously airway surfactant DSPC and PG in humans. When compared within the same patient, DSPC and PG had similar fractional synthesis rates, but PG had a shorter PT, suggesting differences in the life cycle of these essential surfactant components.

Kordiimonas lacus sp. nov., isolated from a ballast water tank, and emended description of the genus Kordiimonas.

A Gram-negative, motile, rod-shaped bacterial strain, designated S3-22(T), was isolated from a sediment sample collected from a ballast water tank of a commercial ship and subjected to a polyphasic taxonomic characterization. The isolate formed small, light-yellow, semi-translucent and circular colonies on solid complex media. The strain was oxidase- and catalase-positive and metabolized a large number of carbon sources. Chemotaxonomic analysis showed ubiquinone Q-10 as predominant respiratory quinone, phosphatidylglycerol and an unidentified glycolipid as major polar lipids and iso-C(17 : 1)ω9c, iso-C(15 : 0), C(16 : 1)ω7c and/or iso-C(15 : 0) 2-OH, C(16 : 0), iso-C(17 : 0) and C(18 : 1)ω7c as major fatty acids and the hydroxy fatty acids iso-C(17 : 0) 3-OH and C(16 : 0) 3-OH. The genomic DNA G+C content was 54.9 mol%. 16S rRNA gene sequence analysis revealed that the isolate has 96.1 % similarity to the type strain of Kordiimonas gwangyangensis, the sole described species within the order Kordiimonadales, and less than 91.0 % similarity to other recognized species. On the basis of phenotypic and genotypic data, strain S3-22(T) represents a novel species of the genus Kordiimonas, for which the name Kordiimonas lacus sp. nov. is proposed, with the type strain S3-22(T) (=CGMCC 1.9109(T) =JCM 16261(T)). An emended description of the genus Kordiimonas is also presented.

Lipidomic analysis reveals that phosphatidylglycerol and phosphatidylethanolamine are newly generated phospholipids in an early-divergent protozoan, Giardia lamblia.

The pathogenic protozoan Giardia lamblia is known to not synthesize membrane lipids de novo. Therefore, it is possible that lipids in the small intestine, where trophozoites colonize, play key roles in regulating the growth and differentiation of this important pathogen. The focus of the current study is to conduct a complete lipidomic analysis and to test the hypothesis that Giardia has some ability to generate new phospholipids (PLs). Using mass spectrometry, now we show that phosphatidylglycerols (PGs) are major PLs followed by phosphatidylcholines (PCs) and phosphatidylethanolamines (PEs) in non-encysting and encysting trophozoites, as well in cysts. The fatty acids attached to these PLs consist mostly of palmitate, palmitoleate, oleate, and linoleate. Results also indicate that PGs and PEs, unlike PCs, are not present in bovine bile and serum, the major sources of lipids of the culture medium, and that they could therefore be produced by fatty acid and headgroup remodeling reactions, circumventing the synthesis of entirely new PLs via de novo pathways. Genomic and transcriptional analyses show the presence of giardial phosphatidylglycerolphosphate synthase (gpgps) and phosphatidylserine decarboxylase (gpsd) genes, which are expressed throughout the life cycle. Bioinformatic and phylogenetic analyses further indicated that both genes are of prokaryotic origin and that they have undergone duplication in the course of evolution. Our studies suggest that the abundance of PG in Giardia is unique among eukaryotes and that its synthesis thus could serve as a potential target for developing new therapies against this waterborne parasite.

Brevibacterium samyangense sp. nov., an actinomycete isolated from a beach sediment.

A novel actinomycete, strain SST-8(T), was isolated from sand sediment of Samyang Beach in Jeju, Korea, and subjected to a polyphasic taxonomic study. The organism, which produced opaque, circular, yellow colonies, with a coryneform morphology, showed the following chemotaxonomic characteristics: meso-diaminopimelic acid as the diamino acid in the peptidoglycan, MK-8(H(2)) as the major menaquinone, phosphatidylglycerol as the only polar lipid, anteiso-C(15 : 0) and anteiso-C(17 : 0) as major fatty acids and a DNA G+C content of 70.7 mol%. The combination of morphological and chemotaxonomic features supported its classification in the genus Brevibacterium. Phylogenetic analyses, based on 16S rRNA gene sequence studies, showed that strain SST-8(T) formed an intermediate branch between the Brevibacterium luteolum/Brevibacterium otitidis and Brevibacterium mcbrellneri/Brevibacterium paucivorans clusters. Sequence similarity calculations based on a neighbour-joining analysis revealed that the closest relatives of strain SST-8(T) were the type strains of B. paucivorans (96.6 %), B. luteolum (96.5 %), B. mcbrellneri (96.3 %), Brevibacterium avium (96.0 %) and B. otitidis (95.9 %). Based on a broad set of phenotypic and genetic data, it was evident that the strain represents a novel species of the genus Brevibacterium. The name Brevibacterium samyangense sp. nov. is proposed, with SST-8(T) (=NRRL B-41420(T)=KCCM 42316(T)) as the type strain.

Correlation of three-dimensional structures with the antibacterial activity of a group of peptides designed based on a nontoxic bacterial membrane anchor.

To understand the functional differences between a nontoxic membrane anchor corresponding to the N-terminal sequence of the Escherichia coli enzyme IIA(Glc) and a toxic antimicrobial peptide aurein 1.2 of similar sequence, a series of peptides was designed to bridge the gap between them. An alteration of a single residue of the membrane anchor converted it into an antibacterial peptide. Circular dichroism spectra indicate that all peptides are disordered in water but helical in micelles. Structures of the peptides were determined in membrane-mimetic micelles by solution NMR spectroscopy. The quality of the distance-based structures was improved by including backbone angle restraints derived from a set of chemical shifts ((1)H(alpha), (15)N, (13)C(alpha), and (13)C(beta)) from natural abundance two-dimensional heteronuclear correlated spectroscopy. Different from the membrane anchor, antibacterial peptides possess a broader and longer hydrophobic surface, allowing a deeper penetration into the membrane, as supported by intermolecular nuclear Overhauser effect cross-peaks between the peptide and short chain dioctanoyl phosphatidylglycerol. An attempt was made to correlate the NMR structures of these peptides with their antibacterial activity. The activity of this group of peptides does not correlate exactly with helicity, amphipathicity, charge, the number of charges, the size of the hydrophobic surface, or hydrophobic transfer free energy. However, a correlation is established between the peptide activity and membrane perturbation potential, which is defined by interfacial hydrophobic patches and basic residues in the case of cationic peptides. Indeed, (31)P solid state NMR spectroscopy of lipid bilayers showed that the extent of lipid vesicle disruption by these peptides is proportional to their membrane perturbation potential.