Abundant Polar Lipids Research Articles

Camel milk polar lipids ameliorate dextran sulfate sodium-induced colitis in mice by modulating the gut microbiota

Milk contains abundant polar lipids, which are vital constituents of biological membranes. These polar lipids are present in the human diet as phospholipids and sphingolipids. Nevertheless, the limited focus has been on the attributes and role of camel milk polar lipids (MPL). In this study, camel MPL were isolated, and the composition of their lipidome was determined using ultra-high-performance liquid chromatography-tandem MS. This study characterized a total of 333 polar lipids, which encompassed glycerophospholipids and sphingolipids. Camel milk is rich in polar lipids, mainly phosphatidylethanolamine, sphingomyelin, and phosphatidylcholine. The results indicated that MPL intervention relieved the clinical symptoms and colon tissue damage in mice with dextran sulfate sodium-induced colitis, along with suppressing the expression of proinflammatory cytokines. Moreover, the administration of MPL partially alleviated mouse gut microbiota dysbiosis by increasing the abundance of probiotics (such as Lachnospiraceae_NK4A136_group and Muribaculaceae) and decreasing the number of harmful bacteria (such as Bacteroides and Parabacteroides). This study was conducted to investigate the potent protective effects of MPL in camel milk treatments on a mouse model of colitis and provided new ideas for the application of camel milk.

Revealing the polar lipidome, pigment profiles, and antioxidant activity of the giant unicellular green alga, Acetabularia acetabulum.

Marine algae are one of the most important sources of high-value compounds such as polar lipids, omega-3 fatty acids, photosynthetic pigments, or secondary metabolites with interesting features for different niche markets. Acetabularia acetabulum is a macroscopic green single-celled alga, with a single nucleus hosted in the rhizoid. This alga is one of the most studied dasycladalean species and represents an important model system in cell biology studies. However, its lipidome and pigment profile have been overlooked. Total lipid extracts were analyzed using hydrophilic interaction liquid chromatography-high resolution mass spectrometry (HILIC-HRMS), tandem mass spectrometry (MS/MS), and high-performance liquid chromatography (HPLC). The antioxidant capacity of lipid extracts was tested using DPPH and ABTS assays. Lipidomics identified 16 polar lipid classes, corresponding to glycolipids, betaine lipids, phospholipids, and sphingolipids, with a total of 191 lipid species, some of them recognized by their bioactivities. The most abundant polar lipids were glycolipids. Lipid classes less studied in algae were identified, such as diacylglyceryl-carboxyhydroxymethylcholine (DGCC) or hexosylceramide (HexCer). The pigment profile of A. acetabulum comprised carotenoids (17.19%), namely cis-neoxanthin, violaxanthin, lutein and β,β-carotene, and chlorophylls a and b (82.81%). A. acetabulum lipid extracts showed high antioxidant activity promoting a 50% inhibition (IC50 ) with concentrations of 57.91 ± 1.20 μg · mL-1 (438.18 ± 8.95 μmol Trolox · g-1 lipid) in DPPH and 20.55 ± 0.60 μg · mL-1 in ABTS assays (918.56 ± 27.55 μmol Trolox · g-1 lipid). This study demonstrates the potential of A. acetabulum as a source of natural bioactive molecules and antioxidant compounds.

Chryseobacterium pennae sp. nov., isolated from poultry feather waste.

A Gram-stain-negative, rod-shaped, non-motile, non-spore-forming, aerobic, yellow-pigmented bacterium was isolated from chicken feather waste collected from an abattoir in Bloemfontein, South Africa. A polyphasic taxonomy study was used to describe and name the bacterial isolate, strain 1_F178T. The 16S rRNA gene sequence analysis and sequence comparison data indicated that strain 1_F178T was a member of the genus Chryseobacterium and was closely related to Chryseobacterium jejuense (99.1%) and Chryseobacterium nakagawai (98.7%). Overall genome similarity metrics (average nucleotide identity, digital DNA–DNA hybridization and average amino acid identity) revealed greatest similarity to the C. jejuense and C. nakagawai type strains but were below the threshold for species delineation. Genome sequencing revealed a genome size of 6.18 Mbp and a G+C content of 35.6 mol%. The major respiratory quinone and most abundant polar lipid of strain 1_F178T were menaquinone-6 and phosphatidylethanolamine, respectively. Strain 1_F178T had a typical fatty acid composition for Chryseobacterium species. On the basis of physiological, genotypic, phylogenetic and chemotaxonomic data, strain 1_F178T constitutes a novel species of Chryseobacterium, for which the name Chryseobacterium pennae sp. nov. is proposed. The type strain is 1_F178T (=LMG 30779T=KCTC 62759T).

Dietary Milk Fat Globule Membrane Restores Decreased Intestinal Mucosal Barrier Development and Alterations of Intestinal Flora in Infant-Formula-Fed Rat Pups.

Milk fat globule membrane (MFGM), which contains abundant polar lipids and glycoproteins, can narrow the gap in growth and development between breast-fed and infant-formula-fed babies. The objective of this study is to evaluate the effect of MFGM supplementation in infant formula on intestinal epithelium maturation, tight junctions, and gut colonization in rat pups. Sprague Dawley rat pups consume one of the five diets from postnatal day 8, including rat breastfeeding (BF), infant formula (IF), and infant formula containing MFGM at 260mg kg-1 body weight (BW), 520mg kg-1 BW, or 1040mg kg-1 BW. Results show that MFGM supplementation in infant formula can facilitate intestinal mucosal barrier maturation via promoting intestinal proliferation and differentiation, and increasing tight junction proteins. In addition, compared with that of the IF pups, the intestinal flora composition of MFGM-supplemented pups is more similar to that of BF pups. MFGM supplementation in infant formula can restore the intestinal development in infant-formula-fed pups, which suggests that the supplementation of MFGM in infant formula can better mimic breast milk.

Comprehensive Characterization of Bovine Milk Lipids: Phospholipids, Sphingolipids, Glycolipids, and Ceramides.

A comprehensive survey on phospholipids (PLs), sphingolipids, glycolipids, and ceramides (Cer) of bovine milk was conducted by liquid chromatography tandem-mass spectrometry. A total of 514 species belonging to 15 classes were identified by an automated search tool (LipidSearch) and a manual analysis of MS2 spectra. Over 60 species were detected for the classes of phosphatidylcholine (PC), phosphatidylinositol, phosphatidylserine, and sphingomyelin (SM), between 20 and 45 species for phosphatidylethanolamine (PE), phosphatidic acid (PA), and lactosylceramide (LacCer), and between 7 and 20 species for phosphatidylglycerol (PG), lyso-phosphatidylcholine, lyso-phosphatidylethanolamine, glucosylceramide (GluCer), PC-plasmalogen (PC-P), PE-plasmalogen, ganglioside, and Cer. The structural assignment for PL classes is straightforward based on class-specific product ion/neutral losses and fatty acid-related product ions. By contrast, structural determination of lipid classes containing a backbone of sphingoid bases (SM, GluCer, LacCer, ganglioside, and Cer) is much more challenging, and combining MS2/MS3 information acquired in both positive and negative modes is sometimes needed. The quantification of all 15 classes of lipids was performed at the species level. A large variation in abundance was observed across the lipid classes; PC, PE, and SM are the most abundant polar lipid classes, with concentrations reaching 120, 150, and 90 μmol/L, respectively, whereas PA, PG, and PC-P are present at very low levels (<1.5 μmol/L) and the remaining classes at an intermediate level (2-45 μmol/L). This is the first comprehensive characterization of minor lipid classes from bovine milk and the information provided can be used as a reference for studying milk lipids.

Robertkochia solimangrovi sp. nov., isolated from mangrove soil, and emended description of the genus Robertkochia.

To date, there is sparse information for the genus Robertkochia with Robertkochia marina CC-AMO-30DT as the only described member. We report here a new species isolated from mangrove soil collected at Malaysia Tanjung Piai National Park and perform polyphasic characterization to determine its taxonomic position. Strain CL23T is a Gram-negative, yellow-pigmented, strictly aerobic, catalase-positive and oxidase-positive bacterium. The optimal growth conditions were determined to be at pH 7.0, 30–37 °C and in 1–2 % (w/v) NaCl. The major respiratory quinone was menaquinone-6 (MK-6) and the highly abundant polar lipids were four unidentified lipids, a phosphatidylethanolamine and two unidentified aminolipids. The 16S rRNA gene similarity between strain CL23T and R. marina CC-AMO-30DT is 96.67 %. Strain CL23T and R. marina CC-AMO-30DT clustered together and were distinguished from taxa of closely related genera in 16S rRNA gene phylogenetic analysis. Genome sequencing revealed that strain CL23T has a genome size of 4.4 Mbp and a G+C content of 40.72 mol%. Overall genome related indexes including digital DNA–DNA hybridization value and average nucleotide identity are 17.70 % and approximately 70%, below the cutoffs of 70 and 95%, respectively, indicated that strain CL23T is a distinct species from R. marina CC-AMO-30DT. Collectively, based on the phenotypic, chemotaxonomic, phylogenetic and genomic evidences presented here, strain CL23T is proposed to represent a new species with the name Robertkochia solimangrovi sp. nov. (KCTC 72252T=LMG 31418T). An emended description of the genus Robertkochia is also proposed.

Genome Insights into the Novel Species Microvirga brassicacearum, a Rapeseed Endophyte with Biotechnological Potential.

Plants harbor a diversity of microorganisms constituting the plant microbiome. Many bioinoculants for agricultural crops have been isolated from plants. Nevertheless, plants are an underexplored niche for the isolation of microorganisms with other biotechnological applications. As a part of a collection of canola endophytes, we isolated strain CDVBN77T. Its genome sequence shows not only plant growth-promoting (PGP) mechanisms, but also genetic machinery to produce secondary metabolites, with potential applications in the pharmaceutical industry, and to synthesize hydrolytic enzymes, with potential applications in biomass degradation industries. Phylogenetic analysis of the 16S rRNA gene of strain CDVBN77T shows that it belongs to the genus Microvirga, its closest related species being M. aerophila DSM 21344T (97.64% similarity) and M. flavescens c27j1T (97.50% similarity). It contains ubiquinone 10 as the predominant quinone, C19:0 cycloω8c and summed feature 8 as the major fatty acids, and phosphatidylcholine and phosphatidylethanolamine as the most abundant polar lipids. Its genomic DNA G+C content is 62.3 (mol %). Based on phylogenetic, chemotaxonomic, and phenotypic analyses, we suggest the classification of strain CDVBN77T within a new species of the genus Microvirga and propose the name Microvirga brassicacearum sp. nov. (type strain CDVBN77T = CECT 9905T = LMG 31419T).

Chryseobacterium pennipullorum sp. nov., isolated from poultry feather waste.

Strain 7_F195T was previously isolated from chicken feather waste collected from an abattoir in Bloemfontein, South Africa. A polyphasic approach was followed to determine if strain 7_F195T belongs to the genus Chryseobacterium and if the organism can be classified as a new species. The nearest neighbours, based on 16S rRNA gene sequence similarity values (indicated in parentheses), were Chryseobacterium flavum KCTC 12877T (98.42 %), Chryseobacterium indologenesLMG 8337T (98.24 %) and Chryseobacterium gleum ATCC 35910T (97.71 %). Genome sequencing revealed a genome size of 4 796 535 bp and a DNA G+C content of 38.6 mol%. The ANI values of strain 7_F195T compared to C. flavum, C. indologenesand C. gleum were 81.45, 81.86 and 82.38 %, respectively. The digital DNA-DNA hybridization values for strain 7_F195T with C. flavum, C. indologenes and C. gleum were 23.7, 23.7 and 24.9 %, respectively. Notable phenotypic differences include the presence of urease activity in C. indologenes LMG 8337T and C. gleum NCTC 11432T, but not in strain 7_F195T or C. flavum KCTC 12877T. The predominant fatty acids of strain 7_F195T were iso-C15 : 0, iso-C17 : 1ω9c and iso-C17 : 0 3-OH and the most abundant polar lipid was phosphatidylethanolamine. Menaquinone-6 was the only respiratory quinone. Based on the data generated from this polyphasic study, strain 7_F195T represents a novel Chryseobacterium species for which the name Chryseobacteriumpennipullorum sp. nov. is proposed. The type strain is 7_F195T (=LMG 30781T=KCTC 62760T).

Surface lipidome of the lone star tick, Amblyomma americanum, provides leads on semiochemicals and lipid metabolism

Lipids extracted from the surface of the lone star tick, Amblyomma americanum, were analyzed by high resolution mass spectrometry. Prior to lipid extraction, the adult ticks were either unfed or fed on cattle, and the fed ticks were in groups either containing males and females together, or containing only males or females. Cholesteryl esters were found on the surfaces of fed females, and they may provide a more complete description of the composition of the mounting sex pheromone. Dihydrocholesteryl esters were detected on the surfaces of unfed males and females, suggesting a possible role in survival during host-seeking. Dehydrodeoxyecdysone, found on fed females, could be a component of the genital sex pheromone. The most abundant polar surface lipids detected were acylglycerides. High levels of sphingolipids and glycerophospholipids on males fed separately might be derived, in part, from sperm development. A high level of a 20:4 fatty acid, presumably arachidonic acid, was found on the surface of fed females, indicating that it may be a component of the genital sex pheromone. A high level of docosenamide was found on the surface of fed females. Wax esters were found on the surfaces of fed ticks but not on unfed ticks. These esters could be involved in elasticity of the cuticle of engorged females or in wax coating of eggs. N-acylethanolamines were found on the surfaces of male and female ticks fed together, and on male ticks fed separately, but were absent or at low levels on females fed separately and on unfed ticks. This pattern suggests a possible role as a metabolic coordination primer pheromone.

Genotypic Variation in Wheat Flour Lysophospholipids.

Lysophospholipids (LPLs) are the most abundant polar lipids in wheat endosperm and naturally complex with amylose, affecting starch physicochemical properties. We analyzed LPLs in wheat flour from 58 cultivars which differ by grain hardness using liquid chromatography mass spectrometry (LCMS). There were significant differences in LPL content between cultivars, demonstrating that genotype rather than environment contributes most to the total variance in wheat endosperm LPLs. Polar lipids such as LPLs may play a role in grain hardness through their interaction with puroindoline proteins, however, no strong correlation between kernel hardness and LPLs was detected. This may reflect the location of LPLs within the starch granule as opposed to the puroindoline proteins outside starch granules. LPLs may have an indirect relationship with kernel hardness as they could share the same origin as polar lipids that interact with puroindoline on the starch granule surface.

Sphaerochaeta multiformis sp. nov., an anaerobic, psychrophilic bacterium isolated from subseafloor sediment, and emended description of the genus Sphaerochaeta.

An anaerobic, psychrophilic bacterium, strain MO-SPC2(T), was isolated from a methanogenic microbial community in a continuous-flow bioreactor that was established from subseafloor sediments collected from off the Shimokita Peninsula of Japan in the north-western Pacific Ocean. Cells were pleomorphic: spherical, annular, curved rod, helical and coccoid cell morphologies were observed. Motility only occurred in helical cells. Strain MO-SPC2(T) grew at 0-17 °C (optimally at 9 °C), at pH 6.0-8.0 (optimally at pH 6.8-7.2) and in 20-40 g NaCl l(-1) (optimally at 20-30 NaCl l(-1)). The strain grew chemo-organotrophically with mono-, di- and polysaccharides. The major end products of glucose fermentation were acetate, ethanol, hydrogen and carbon dioxide. The abundant polar lipids of strain MO-SPC2(T) were phosphatidylglycolipids, phospholipids and glycolipids. The major cellular fatty acids were C14 : 0, C16 : 0 and C16 : 1ω9. Isoprenoid quinones were not detected. The G+C content of the DNA was 32.3 mol%. 16S rRNA gene-based phylogenetic analysis showed that strain MO-SPC2(T) was affiliated with the genus Sphaerochaeta within the phylum Spirochaetes, and its closest relatives were Sphaerochaeta pleomorpha Grapes(T) (88.4 % sequence identity), Sphaerochaeta globosa Buddy(T) (86.7 %) and Sphaerochaeta coccoides SPN1(T) (85.4 %). Based on phenotypic characteristics and phylogenetic traits, strain MO-SPC2(T) is considered to represent a novel species of the genus Sphaerochaeta, for which the name Sphaerochaeta multiformis sp. nov. is proposed. The type strain is MO-SPC2(T) ( = JCM 17281(T) = DSM 23952(T)). An emended description of the genus Sphaerochaeta is also proposed.

Acetobacteroides hydrogenigenes gen. nov., sp. nov., an anaerobic hydrogen-producing bacterium in the family Rikenellaceae isolated from a reed swamp.

A strictly anaerobic, mesophilic, carbohydrate-fermenting, hydrogen-producing bacterium, designated strain RL-C(T), was isolated from a reed swamp in China. Cells were Gram-stain-negative, catalase-negative, non-spore-forming, non-motile rods measuring 0.7-1.0 µm in width and 3.0-8.0 µm in length. The optimum temperature for growth of strain RL-C(T) was 37 °C (range 25-40 °C) and pH 7.0-7.5 (range pH 5.7-8.0). The strain could grow fermentatively on yeast extract, tryptone, arabinose, glucose, galactose, mannose, maltose, lactose, glycogen, pectin and starch. The main end products of glucose fermentation were acetate, H2 and CO2. Organic acids, alcohols and amino acids were not utilized for growth. Yeast extract was not required for growth; however, it stimulated growth slightly. Nitrate, sulfate, sulfite, thiosulfate, elemental sulfur and Fe(III) nitrilotriacetate were not reduced as terminal electron acceptors. Aesculin was hydrolysed but not gelatin. Indole and H2S were produced from yeast extract. The G+C content of the genomic DNA was 51.2 mol%. The major cellular fatty acids were iso-C15 : 0, anteiso-C15 : 0 and C16 : 0. The most abundant polar lipid of strain RL-C(T) was phosphatidylethanolamine. 16S rRNA gene sequence analysis revealed that the isolate belongs to the uncultured Blvii28 wastewater-sludge group (http://www.arb-silva.de/) in the family Rikenellaceae of the phylum Bacteroidetes, and shared low sequence similarities with the related species Alistipes shahii WAL 8301(T) (81.8 %), Rikenella microfusus ATCC 29728(T) (81.7 %) and Anaerocella delicata WN081(T) (80.9 %). On the basis of these data, a novel species in a new genus of the family Rikenellaceae is proposed, Acetobacteroides hydrogenigenes gen. nov., sp. nov. The type strain of the type species is RL-C(T) ( = JCM 17603(T) = DSM 24657(T) = CGMCC 1.5173(T)).

Spirochaeta psychrophila sp. nov., a psychrophilic spirochaete isolated from subseafloor sediment, and emended description of the genus Spirochaeta.

An obligately anaerobic, psychrophilic spirochaete, strain MO-SPC1(T), was isolated from a methanogenic microbial community grown in a continuous-flow bioreactor. Originally, this community was obtained from subseafloor sediments off the Shimokita Peninsula of Japan in the north-western Pacific Ocean. The cells were motile, Gram-stain-negative, helical, 0.25-0.55×3.6-15 µm, with a wavelength of approximately 0.5-0.6 µm. Strain MO-SPC1(T) grew at 0-18 °C (optimally at 15 °C), at pH 6.0-7.5 (optimally at pH 6.8-7.0) and in 20-70 g NaCl l(-1) (optimally at 30-40 NaCl l(-1)). The strain grew chemo-organotrophically with mono-, di- and polysaccharides. The major end products of glucose fermentation were acetate, ethanol, hydrogen and carbon dioxide. The abundant polar lipids of strain MO-SPC1(T) were diphosphatidylglycerol, phosphatidylglycerol, unknown phospholipids and an unknown lipid. The major cellular fatty acids (>5% of the total) were C(14 : 0), C(16 : 0), iso-C(13 : 0), iso-C(14 : 0), iso-C(15 : 0), anteiso-C(13 : 0) and anteiso-C(15 : 0). To the best of our knowledge, this is the first report of the fatty acids iso-C(13 : 0) and anteiso-C(13 : 0) from a species of the genus Spirochaeta. Isoprenoid quinones were not found. The G+C content of the genomic DNA was 39.8 mol%. 16S rRNA gene sequence-based phylogenetic analysis showed that strain MO-SPC1(T) was affiliated with the genus Spirochaeta, and its closest relatives were Spirochaeta isovalerica MA-2(T) (95.6% sequence identity) and Spirochaeta litoralis R1(T) (89.4%). Based on its phenotypic characteristics and phylogenetic traits, strain MO-SPC1(T) is placed in a separate taxon at the level of a novel species within the genus Spirochaeta, for which the name Spirochaeta psychrophila sp. nov. is proposed, reflecting its true psychrophilic physiology. The type strain is MO-SPC1(T) ( = JCM 17280(T) = DSM 23951(T)). To our knowledge, this is the first report of an isolate of the phylum Spirochaetes from a deep-sea sedimentary environment, and of an obligately psychrophilic nature.

Hydrogenispora ethanolica gen. nov., sp. nov., an anaerobic carbohydrate-fermenting bacterium from anaerobic sludge

An anaerobic, spore-forming, ethanol-hydrogen-coproducing bacterium, designated LX-BT, was isolated from an anaerobic sludge treating herbicide wastewater. Cells of strain LX-BT were non-motile rods (0.3-0.5×3.0-18.0 µm). Spores were terminal with a bulged sporangium. Growth occurred at 20-50 °C (optimum 37-45 °C), pH 5.0-8.0 (optimum pH 6.0-7.7) and 0-2.5% (w/v) NaCl. The strain could grow fermentatively on glucose, maltose, arabinose, fructose, xylose, ribose, galactose, mannose, raffinose, sucrose, pectin, starch, glycerol, fumarate, tryptone and yeast extract. The major end-products of glucose fermentation were acetate, ethanol and hydrogen. Yeast extract was not required but stimulated growth. Nitrate, sulfate, thiosulfate, elemental sulfur, sulfite, anthraquinone-2,6-disulfonate, fumarate and Fe (III) nitrilotriacetate were not used as terminal electron acceptors. The G+C content of the genomic DNA was 56.1 mol%. The major cellular fatty acids were anteiso-C15:0, iso-C14:0 and C16:0. The most abundant polar lipids of strain LX-BT were diphosphatidylglycerol and phosphatidylglycerol. 16S rRNA gene sequence analysis revealed that it belongs to an as-yet-unidentified taxon at the order- or class-level (OPB54) within the phylum Firmicutes, showing 86.5% sequence similarity to previously described species of the Desulfotomaculum cluster. The name Hydrogenispora ethanolica gen. nov., sp. nov. is proposed to accommodate strain LX-BT (=DSM 25471T=JCM 18117T=CGMCC 1.5175T) as the type strain.

Paludibacter jiangxiensis sp. nov., a strictly anaerobic, propionate-producing bacterium isolated from rice paddy field

A mesophilic, obligately anaerobic, propionate-producing fermentative bacterium, designated strain NM7(T), was isolated from rural rice paddy field. Cells of strain NM7(T) are Gram-negative, non-motile, non-spore-forming, short rods, and negative for catalase. The strain grew optimally at 37°C (the range for growth 15-40°C) and pH 7.0 (pH 5.0-7.5). The strain could grow fermentatively on various sugars, including arabinose, xylose, fructose, galactose, glucose, mannose, cellobiose, lactose, maltose, sucrose, pectin and starch. The main end products of glucose fermentation were acetate and propionate. Yeast extract was not required but stimulated the growth. Nitrate, sulfate, thiosulfate, elemental sulfur, sulfite, and Fe(III) nitrilotriacetate were not used as terminal electron acceptors. The G+C content of genomic DNA was 42.8mol%. The major cellular fatty acids were C15:0, anteiso-C15:0, C16:0, and C17:0. The most abundant polar lipid of strain NM7(T) was phosphatidylethanolamine. 16S rRNA gene sequence analysis revealed that it belongs to the family Porphyromonadaceae of the phylum Bacteroidetes. The closest recognized species was Paludibacter propionicigenes (91.4% similarity in 16S rRNA gene sequence). A novel species, Paludibacter jiangxiensis sp. nov., is proposed to accommodate strain NM7(T) (=JCM 17480(T)=CGMCC 1.5150(T)=KCTC 5844(T)).

Chryseobacterium angstadtii sp. nov., isolated from a newt tank

As part of an undergraduate microbiology course, a yellow-orange-pigmented, Gram-staining negative, rod-shaped, non-motile bacterial strain was isolated from a glass tank housing several red-spotted newts (Notophthalmus viridescens). The sequence of the 16S rRNA gene of this strain, designated KM(T), was 97.4-98.0 % similar to those of the type strains of Chryseobacterium luteum, C. shigense and C. vrystaatense, while the similarity levels for protein-coding genes were less than 94.7 % for rpoB, less than 92.1 % for groEL and less than 87.1 % for gyrB. These values are lower than for many other established distinct species. Polyphasic characterization and comparison to these relatives revealed that strain KM(T) was similar to other Chryseobacterium strains in that it contained MK-6 as its major respiratory quinone and phosphatidylethanolamine as the most abundant polar lipid, produced flexirubin-type pigments, oxidase and catalase and primarily contained the fatty acids iso-C15 : 0, iso-C17 : 1ω9c, iso-C17 : 0 3-OH and summed feature 3 (comprising C16 : 1ω6c and/or C16 : 1ω7c). Based on the results of this study, strain KM(T) represents a novel species, for which the name Chryseobacterium angstadtii sp. nov. is proposed. The type strain is KM(T) ( = ATCC BAA-2160(T) = NRRL B-59516(T) = KCTC 23297(T)).

Paenibacillus typhae sp. nov., isolated from roots of Typha angustifolia L.

A Gram-stain-positive, facultatively anaerobic and rod-shaped bacterium, designated strain xj7(T), was isolated from roots of Typha angustifolia L. growing in Beijing Cuihu Wetland, China. The isolate was identified as a member of the genus Paenibacillus based on phenotypic characteristics and phylogenetic inference. The novel strain was spore-forming, motile, catalase-positive and oxidase-negative. Optimal growth of strain xj7(T) occurred at 28-30 °C and pH 7.0-7.5. Diphosphatidylglycerol was the most abundant polar lipid and occurred along with phosphatidylglycerol, phosphatidylethanolamine, one unknown phospholipid and three unknown aminophospholipids. The diamino acid found in the cell-wall peptidoglycan was meso-diaminopimelic acid. The predominant isoprenoid quinone was MK-7. The major fatty acid components were anteiso-C15 : 0 (56.1 %), iso-C16 : 0 (9.1 %), C16 : 0 (8.0 %), iso-C14 : 0 (6.3 %) and iso-C15 : 0 (5.1 %). The G+C content of genomic DNA was 47.9 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain xj7(T) fell within the evolutionary radiation encompassed by the genus Paenibacillus, its closest neighbours were Paenibacillus borealis KK19(T) (97.5 %) and Paenibacillus durus DSM 1735(T) (97.1 %). However, the DNA-DNA relatedness values between strain xj7(T) and P. borealis KK19(T) and between strain xj7(T) and P. durus DSM 1735(T), were both 35 %. Based on phenotypic, chemotaxonomic and phylogenetic properties, strain xj7(T) is considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus typhae sp. nov. is proposed. The type strain is xj7(T) ( = CGMCC 1.11012(T) = DSM 25190(T)).

Oligosphaera ethanolica gen. nov., sp. nov., an anaerobic, carbohydrate-fermenting bacterium isolated from methanogenic sludge, and description of Oligosphaeria classis nov. in the phylum Lentisphaerae

A mesophilic, obligately anaerobic, carbohydrate-fermenting bacterium, designated 8KG-4(T), was isolated from an upflow anaerobic sludge blanket reactor treating high-strength organic wastewater from salted vegetable production processes. Cells of strain 8KG-4(T) were non-motile, spherical and 0.7-1.5 µm in diameter (mean, 1.0 µm). Spore formation was not observed under any culture conditions tested. The strain grew optimally at 37 °C (range for growth 25-40 °C) and pH 7.0 (range, pH 6.5-7.5), and could grow fermentatively on glucose, ribose, xylose, galactose and sucrose. The main end products of glucose fermentation were acetate, ethanol and hydrogen. Organic acids, alcohols and amino acids were not utilized for growth. Yeast extract was not required for growth. Nitrate, sulfate, thiosulfate, elemental sulfur, sulfite and Fe(III) nitrilotriacetate were not used as terminal electron acceptors. The G+C content of the genomic DNA was 61.1 mol%. 16S rRNA gene sequence analysis revealed that the isolate represented a previously uncultured lineage at the subphylum level within the phylum Lentisphaerae known as 'WWE2 subgroup I'. The major cellular fatty acids were anteiso-C(15 : 0), iso-C(16 : 0), C(16 : 0) and anteiso-C(17 : 0). Respiratory quinones were not detected. The most abundant polar lipid of strain 8KG-4(T) was phosphatidylethanolamine. A novel genus and species, Oligosphaera ethanolica gen. nov., sp. nov., is proposed to accommodate strain 8KG-4(T) ( = JCM 17152(T) = DSM 24202(T) = CGMCC 1.5160(T)). In addition, we formally propose Oligosphaeria classis nov. and the subordinate taxa Oligosphaerales order nov. and Oligosphaeraceae fam. nov.

Puroindolines are associated with decreased polar lipid breakdown during wheat seed development

The wheat Hardness (Ha) locus consists of Puroindoline a (Pina) and Puroindoline b (Pinb) and controls whether wheat is soft or hard textured. PINA and PINB act cooperatively to create grain softness and are associated with increased polar lipids at seed maturity. Here we examined developing seeds varying in PINA or PINB content to identify when polar lipid differences occur. One population carried Wild Type (WT) PINA while varying for the presence of PINB, while the other population carried a WT PINB and segregated for PINA. For the PINB segregating population, polar lipids were maximal on a per mg dry weight basis at 7–14 days after anthesis (DAA) while for PINA segregating population, total polar lipids were maximal at 7–21 DAA. The most abundant polar lipids at maturity were mono- and di- galactosyldiglyceride. No individual polar lipid species were specific to PINA or PINB. The effect of both PINA and PINB increased throughout seed development with greater decreases in the most abundant polar lipids in genotypes lacking either PINA or PINB. The results indicate that PINA and PINB act cooperatively to prevent polar lipid breakdown during seed maturation and that this process is central to the development of grain softness.

Polar lipid fatty acids, LPS-hydroxy fatty acids, and respiratory quinones of three Geobacter strains, and variation with electron acceptor

The polar lipid fatty acids, lipopolysaccharide hydroxy-fatty acids, and respiratory quinones of Geobacter metallireducens str. GS-15, Geobacter sulfurreducens str. PCA, and Geobacter bemidjiensis str. Bem are reported. Also, the lipids of G. metallireducens were compared when grown with Fe(3+) or nitrate as electron acceptors and G. sulfurreducens with Fe(3+) or fumarate. In all experiments, the most abundant polar lipid fatty acids were 14:0, i15:0, 16:1 omega 7c, 16:1 omega 5c, and 16:0; lipopolysaccharide hydroxy-fatty acids were dominated by 3oh16:0, 3oh14:0, 9oh16:0, and 10oh16:0; and menaquinone-8 was the most abundant respiratory quinone. Some variation in lipid profiles with strain were observed, but not with electron acceptor.