The Identification and Quantification of Phospholipids from Thermus and Meiothermus Bacteria

Structural identities of the major phospholipid (PL-2), minor phospholipid (PL-1) and trace phospholipid (PL-0) from representative strains of the genera Thermus and Meiothermus were established. Phospholipids were quantified using phosphorus-31 nuclear magnetic resonance (³¹P-NMR). The structures of the major phospholipid (PL-2) from Thermus filiformis MOK14.7 and Meiothermus ruber WRG6.9 were identified as 2′-O-(1,2-diacyl-sn-glycero-3-phospho)-3′-O-(α-N-acetylglucosaminyl)-N-glyceroyl alkylamine (GlcNAc-PGAA) and 2′-O-(2-acylalkyldiol-1-O-phospho)-3′-O-(α-N-acetylglucosaminyl)-N-glyceroyl alkylamine (GlcNAc-diolPGAA). Interestingly, M. ruber contained only a diacyl form of GlcNAc-PGAA (87 %), while T. filiformis contained both GlcNAc-PGAA (59 %) and GlcNAc-diolPGAA (18 %). The structures of the minor phospholipid (PL-1) were established as 2′-O-(1,2-diacyl-sn-glycero-3-phospho)-3′-O-(α-glucosaminyl)-N-glyceroyl alkylamine (GlcN-PGAA, 13 %) in T. filiformis and 2′-O-(1,2-diacyl-sn-glycero-3-phospho)-3′-O-(α-galactosaminyl)-N-glyceroyl alkylamine (GalN-PGAA, 19 %) in M. ruber. This is the first reliable discovery of phosphatidylglyceroylalkylamines modified by glucosamine or galactosamine with a free amino group. No signs of diol-based phosphatidylglyceroylalkylamines were found in PL-1 phospholipids. Similar to PL-2, trace phospholipid (PL-0) from T. filiformis contained both unsubstituted diol-based phosphatidylglyceroylalkylamine (diolPGAA) and PGAA, while M. ruber contained only free PGAA. Unlike analysis using TLC, the diol form of phosphatidylglyceroylalkylamines is clearly resolved from the diacyl form via ³¹P-NMR.     

Co-liquefaction of microalgae and synthetic polymer mixture in sub- and supercritical ethanol

Co-liquefaction of microalgae (Spirulina) and synthetic polymer (HDPE, high-density polyethylene) in sub- and supercritical ethanol was investigated in a stainless steel autoclave (1000 mL) at different reaction temperatures (T), Spirulina/HDPE ratio (R₁), (Spirulina + HDPE)/ethanol ratio (R₂) and solvent filling ratio (R₃). Results showed that the addition of Spirulina to HDPE liquefaction could make the conversion conditions of HDPE milder. The yield of bio-oil obtained at 613 K with a 1/10 R₂ and a 2/10 R₃ was increased by 44.81 wt.% when the R₁ was raised from 0/10 to 4/6. Meanwhile, the synergetic effects (SE) between HDPE and Spirulina were increased from 0 to 30.39 wt.%. Further increasing R₁ resulted in a decrease in SE. The yields of bio-oil increased with increasing R₂ firstly and then declined. An opposite trend was observed for the yield of residue. The effect of R₃ to the yields of liquefaction products was similar to that of R₂. The content of C and H in bio-oils reduced with increasing R₁, while the content of O increased. The bio-oil from pure Spirulina liquefaction runs mainly consisted of oxygen-containing compounds, such as carboxylic acids, esters and ketones. But the major components of bio-oil from co-liquefaction of Spirulina and HDPE mixture were similar to those of pure HDPE-derived bio-oil, in which aliphatic hydrocarbons dominated.     

Synthesis and Characterization of Cis- and Trans-Trimethyltriphenylcyclotrisiloxane

2,4,6-Trimethyl-2,4,6-triphenylcyclotrisiloxane (P₃) exists as cis and trans-stereoisomers. Herein, we present the detailed synthesis and characterization of the cis- and trans-P₃ isomers. After preparation of the mixed cyclic methylphenylsiloxanes, it was found that vacuum distillation was the best method for separating P₃ from the mixture of P₃ and 2,4,6,8-tetramethyl-2,4,6,8-tetraphenylcyclotetrasiloxane (P₄) on a large scale and that pure cis-P₃ can be isolated by washing the mixed P₃ isomers with methanol. It is also shown that a selective crystallization method was successful for isolating cis-P₃ from the mixture of P₃ and P₄ directly and that large crystals may be obtained. Using gas chromatography and nuclear magnetic resonance (NMR) spectroscopy, the two different isomers and four different isomers in P₃ and P₄, respectively, are easily identified. The nuclear magnetic resonance (NMR) spectra, differential scanning calorimeter (DSC) thermograms, and infrared (IR) spectra with various ratios of cis-P₃ and trans-P₃ were also analyzed. A melting point depression of the cis-P₃ was observed with an increased amount of trans-P₃ for the mixed isomers, as expected. These P₃ stereochemical isomers provide valuable starting materials for the preparation of stereoregular siloxanes using ring-opening polymerization.     

Molecular Genetics of Conjunctival Melanoma and Prognostic Value of TERT Promoter Mutation Analysis

The aim of this study was exploration of the genetic background of conjunctival melanoma (CM) and correlation with recurrent and metastatic disease. Twenty-eight CM from the Rotterdam Ocular Melanoma Study group were collected and DNA was isolated from the formalin-fixed paraffin embedded tissue. Targeted next-generation sequencing was performed using a panel covering GNAQ, GNA11, EIF1AX, BAP1, BRAF, NRAS, c-KIT, PTEN, SF3B1, and TERT genes. Recurrences and metastasis were present in eight (29%) and nine (32%) CM cases, respectively. TERT promoter mutations were most common (54%), but BRAF (46%), NRAS (21%), BAP1 (18%), PTEN (14%), c-KIT (7%), and SF3B1 (4%) mutations were also observed. No mutations in GNAQ, GNA11, and EIF1AX were found. None of the mutations was significantly associated with recurrent disease. Presence of a TERT promoter mutation was associated with metastatic disease (p-value = 0.008). Based on our molecular findings, CM comprises a separate entity within melanoma, although there are overlapping molecular features with uveal melanoma, such as the presence of BAP1 and SF3B1 mutations. This warrants careful interpretation of molecular data, in the light of clinical findings. About three quarter of CM contain drug-targetable mutations, and TERT promoter mutations are correlated to metastatic disease in CM.     

Distribution and Differential Expression of (E)-4,8-Dimethyl-1,3,7-Nonatriene in Leaf and Floral Volatiles of Magnolia and Liriodendron Taxa

Analyses of volatiles emitted from artificially damaged leaves attached to branches of seven Magnolia taxa revealed the presence of (Z)-3-hexenyl acetate, (Z)-3-hexenol (the green odor compounds), and several mono- and sesquiterpenes, e.g., (Z)- and (E)-β-ocimene and caryophyllene. An herbivore-induced leaf volatile, (E)-4,8-dimethyl-1,3,7-nonatriene, known as a predator attractant in agricultural plants, was emitted 4–6 hr after leaves were damaged in M. hypoleuca. The damaged leaves of M. grandiflora, however, immediately released (E)-4,8-dimethyl-1,3,7-nonatriene. Undamaged leaves of Magnolia species examined did not emit volatile compounds. In addition, detached flowers of six Magnolia taxa and Liriodendron tulipifera also emit (E)-4,8-dimemyl-1,3,7-nonatriene as a floral volatile (up to 30% in some species); the chemical was also emitted from the intact flowers of M. heptapeta and M. salicifolia.     

Preparation and characterization of ortho-biguanidinyl benzoyl chitosan hydrochloride and its antibacterial activities

A novel derivative of chitosan (CTS), ortho-biguanidinyl benzoyl chitosan hydrochloride (o-BGBCH), was prepared with CTS and ortho-biguanidinyl benzoyl chloride, which was synthesized by acid chloride reaction of ortho-biguanidinyl benzonic acid hydrochloride (o-BGBA), as starting material in the medium consisted of methylsulfonic acid (MeSO₃H) and dimethyl sulfoxide. Structure of o-BGBCH was characterized by FT-IR and ¹H NMR, molecular weight of o-BGBCH was determined through gel permeation chromatography, and degree of substitution (DS) of guanidinylation of o-BGBCH was measured using elemental analysis technique. Meanwhile, the minimum inhibitory concentration of o-BGBCHs against Escherichia coli, a Gram-negative bacterium, and Staphylococcus aureus, a Gram-positive bacterium, were ascertained by agar plate method. Compared with CTS hydrochloride, o-BGBCHs had much stronger antimicrobial activities, and these activities improved with the increase of their DS of guanidinylation. When the DS of o-BGBCH reached or exceeded 32.7 %, its antibacterial activities against the tested bacteria were higher than that of Bromo-Geramium.     

Relationship between elastic and mechanical properties of dental ceramics and their index of brittleness

The purpose of the study was to verify the effects of a number of materials’ parameters (crystalline content; Young's modulus, E; biaxial flexure strength, σ_i; Vickers hardness, VH; fracture toughness, K_Ic; fracture surface energy, γ_f; and index of brittleness, B) on the brittleness of dental ceramics. Five commercial dental ceramics with different contents of glass phase and crystalline particles were studied: a vitreous porcelain (VM7/V), a porcelain with 16 vol% leucite particles (d.Sign/D), a glass-ceramic with 29 vol% leucite particles (Empress/E1), a glass-ceramic with 58 vol% lithium-disilicate needle-like particles (Empress 2/E2), and a glass-infiltrated alumina composite with 65 vol% crystals (In-Ceram Alumina/IC). Discs were constructed according to manufacturers’ instructions, ground and polished to final dimensions (12 mm × 1.1 mm). Elastic constants were determined by ultrasonic pulse-echo method. σ_i was determined by piston-on-3-balls method in inert condition. VH was determined using 19.6 N load and K_Ic was determined by indentation strength method. γ_f was calculated from the Griffith–Irwin relation and B by the ratio of HV to K_Ic. IC and E2 showed higher values of σ_i, E, K_Ic and γ_f, and lower values of B compared to leucite-based glass-ceramic and porcelains. Positive correlations were observed for σ_i versus K_Ic, and K_Ic versus E^1/2, however, E did not show relationship with HV and B. The increase of crystalline phase content is beneficial to decrease the brittleness of dental ceramics by means of both an increase in fracture surface energy and a lowering in index of brittleness.     

Temperature-dependent aggregation of bio-surfactants in aqueous solutions of galactose and lactose: Volumetric and viscometric approach

Modulation in the aggregation behavior of bio-surfactants(bile salts), sodium cholate(NaC) and sodium deoxycholate(NaDC) in aqueous solutions of carbohydrates(galactose and lactose) have been investigated by measuring the density(ρ), speed of sound(u) and viscosity(η) of the mixtures at different temperatures293.15, 298.15, 303.15, 308.15 and 313.15 K. The density and speed of sound data have been used to calculate various volumetric and compressibility parameters such as apparent molar volume(V_φ), isentropic compressibility(κ_s), apparent molar adiabatic compression(κ_(s, φ)) to get a better insight into the micellization mechanism of bile salts. Further, the viscosity data have been studied in the light of relative viscosity(η_r) and viscous relaxation time(τ). Some derived parameters such as free volume(V_f), internal pressure(πi) and molar cohesive energy(MCE) of Na C and Na DC in aqueous solution of saccharides have also been calculated from viscosity data in conjunction with density and speed of sound values. All the calculated and derived parameters provide qualitative information regarding the nature of interactions i.e. solute–solute, solute–solvent and solvent–solvent in the solution.     

Preparation and characterization of graft copolymers of methyl methacrylate and poly(n-hexyl isocyanate) macromonomers

Living poly(n-hexyl isocyanate) (PHIC) was deactivated with methacryloyl chloride to produce methacryl-terminated poly(n-hexyl isocyanate) (PHIC-MA) rodlike macromonomers. Radical copolymerization of methyl methacrylate (MMA) with PHIC-MA was performed using 2,2′-azobis(isobutyronitrile) as an initiator in benzene at 60 °C to prepare poly(methyl methacrylate)-graft-poly(n-hexyl isocyanate) (PMMA-graft-PHIC) graft copolymers. The monomer reactivity ratios of MMA (M₁) and PHIC-MA (M₂) were evaluated as r₁=11.5 and r₂=∼0, exhibiting remarkably lower reactivity of PHIC-MA macromonomer than that of common macromonomers. The resultant graft copolymers were characterized using gel permeation chromatography equipped with low-angle laser light-scattering to determine the molecular weights, and equipped with a refractive index detector and an ultraviolet light detector to estimate a PHIC weight fraction of PMMA-graft-PHIC at the ith elution volume of the GPC chromatogram. There are 2-3 PHIC grafts per PMMA molecule, and the PHIC rodlike chains might be difficult to introduce into the PMMA main chains having higher molecular weights. A specific dimension of PMMA-graft-PHIC in solution was discussed in detail.     

Synthesis and antimicrobial activities of polysiloxane-containing quaternary ammonium salts on bacteria and phytopathogenic fungi

A series of dimethylaminopropyl benzyl chloride grafted polysiloxanes (PDMS-g-BCs) with tunable molecular weights and cationic content were synthesized, and the effect of polymer structure on the antimicrobial activities against bacteria (Escherichia coli (E. coli) and Staphylococcus albus (S. albus)) and phytopathogenic fungi (Rhizoctonia solani (R. solani) and Fusarium oxysporum f. sp. cubense race 4 (Foc4)) were systematically assessed. The antibacterial activity was evaluated by determining the minimum inhibitory concentration (MIC) against E. coli and S. albus by the broth dilution method, and the antifungal activity was measured by mycelia growth inhibition as well as by the MIC and minimum fungicidal concentration (MFC) values. The molecular weight and cationic content were major determinants of the activities of PDMS-g-BCs; when the molecular weight was approximately 2500 g/mol and the cationic content was approximately 20 mol% of the total siloxane units, PDMS-g-BCs gained strong antimicrobial activities toward both E. coli and Foc4, comparable to those of a commonly used broad-spectrum microbicide benzalkonium chloride, making PDMS-g-BCs promising fungicidal agents for plant disease control.     

Comparison of thermomechanical properties of statistical, gradient and block copolymers of isobornyl acrylate and n-butyl acrylate with various acrylate homopolymers

Well-defined statistical, gradient and block copolymers consisting of isobornyl acrylate (IBA) and n-butyl acrylate (nBA) were synthesized via atom transfer radical polymerization (ATRP). To investigate structure-property correlation, copolymers were prepared with systematically varied molecular weights and compositions. Thermomechanical properties of synthesized materials were analyzed via differential scanning calorimetry (DSC), dynamic mechanical analyses (DMA) and small-angle X-ray scattering (SAXS). Glass transition temperature (T_g) of the resulting statistical poly(isobornyl acrylate-co-n-butyl acrylate) (P(IBA-co-nBA)) copolymers was tuned by changing the monomer feed. This way, it was possible to generate materials which can mimic thermal behavior of several homopolymers, such as poly(t-butyl acrylate) (PtBA), poly(methyl acrylate) (PMA), poly(ethyl acrylate) (PEA) and poly(n-propyl acrylate) (PPA). Although statistical copolymers had the same thermal properties as their homopolymer equivalents, DMA measurements revealed that they are much softer materials. While statistical copolymers showed a single T_g, block copolymers showed two T_gs and DSC thermogram for the gradient copolymer indicated a single, but very broad, glass transition. The mechanical properties of block and gradient copolymers were compared to the statistical copolymers with the same IBA/nBA composition.     

Sex Pheromone Stereochemistry and Purity Affect Field Catches of Male Aphids

Male blackberry-cereal aphids, Sitobion fragariae (Walker), were caught in the ield by water traps releasing synthetic (4aS, 7S, 7aR)-nepetalactone, the major sex pheromone component. The presence of the enantiomer (4aR,7R,7aS)-nepetalactone reduced catches and a plant-extracted (4aS,7S,7aR)-nepetalactone was less effective than the 99% (7S)-lactone. A more extensive trial with the bird cherry-oat aphid, Rhopalosiphum padi, involving the pheromone comprising the stereochemically related (4aS,7S,7aR)-nepetalactol showed a similar trend. The (7R)-isomer caught fewer males than the (7S)-isomer, but in this case the addition of high-purity (7S)-lactol to make a 50% blend caught as many males as pure (7S)-lactol. With plant-derived lactol, further purification did not significantly increase the catch. It is suggested that trace compounds associated with reduced enantiomeric purity in terms of the (7S)-configuration or from plant sources reduce activity of the sex pheromone components. Male damson-hop aphids, Phorodon humuli (Schrank), were also caught in the synthetic lactol traps, and it is suggested that this is due to traces of the (4aR,7S,7aS)-nepetalactols, which comprise the sex pheromone for this species. The significance for aphid chemical ecology studies and pest control strategies is discussed.     

Master curve of crystal growth rate and its corresponding state in polymeric materials

The temperature dependence of linear crystal growth rate (G) for various polymers shows a bell shape with the maximum growth rate (G_max). The G_max shows remarkable molecular weight dependence. The G_max was formulated on the basis of a crystallization theory, both for Arrhenius and WLF expressions in the molecular transport term. The plots of the reduced growth rate (G/G_max) against the reduced temperature (T/T_cmax) for a given polymer showed a single master curve without molecular weight dependence. The ratio of G₀/G_max gave a constant value for each polymer, indicating a material constant. On the basis of G_max for many polymers, a universal master curve was observed when the ratio of ln(G/G_max)/ln(G₀/G_max) was plotted against the reduced temperature (T/T_cmax).     

Characterization and solubility measurement and prediction of selected arylamines in hexane, methanol and benzene

The solubility of nine arylamine molecules in benzene, methanol and hexane was measured. These molecules were: triphenylamine, N-(4-methyl phenyl) N,N bis phenyl amine, N-(3-methyl phenyl) N,N bis phenyl amine, N,N-bis(4-methyl phenyl) N-phenyl amine, N,N-bis(3-methyl phenyl) N-phenyl amine, tritolylamine (N,N,N-tris-(4-methylphenyl)amine), N,N-bis-(4-methylphenyl)-N-(3-methylphenyl)amine, N,N-bis-(3-methylphenyl)-N-(4-methylphenyl)amine, and N,N,N-tris-(3-methylphenyl)amine. The solubility of these molecules was estimated using ideal solution theory, the Hildebrand equation, and UNIQUAC method. The ideal solution theory and the Hildebrand equation were not able to estimate solubility with high precision. However, UNIQUAC method was able to estimate the solubility with good accuracy. It was found that substitution of methyl group regardless of its number in aryl ring increases the solubility. In addition, meta-substitution always results in higher solubility regardless of the nature of the solvent. Physical properties, as well as electrochemical properties of these materials were also provided. Based on these data, the most promising candidates for device preparation should be: mTTA, TTA, mmmTTA, and mono-TPA. However, the only way to prove the above ranking would be to test the candidates in actual devices, which is outside the scope of this paper.     

Structure and density of deposits formed on filter fibers by inertial particle deposition and bounce

The morphology and packing density of particle deposits formed by accumulation on thin steel fibers suspended in an aerosol stream were studied by confocal microscopy. Measurements were made with electrically neutral polystyrene spheres (d_P=1.3, 2.0, 2.6 and 5.2 μm) as a function of flow velocity (v=0.7–5 m/s) and fiber diameters (d_F=8 and 30 μm). Deposition under these conditions was dominated by inertia (Stokes number St=0.3–9), interception (interception parameter R=0.04–0.35) and particle bounce, with a negligible contribution from diffusion.The experiments show a systematic transition of deposit morphologies with a newly introduced particle bounce parameter β～St/R, where St and R are based on the diameter d_F of the bare fiber. Compact, forward facing deposit structures dominate in case of significant particle bounce (i.e. for β>β?, where β* represents the critical conditions for the onset of bounce on the bare fiber). Dendritic structures with pronounced sideways branching are formed at β<β*. R is of relatively little influence as an independent parameter, probably because interception occurs mostly on preexisting deposit structures with dimensions in the order of d_P.The mean porosity ε of the deposit structures was determined on the basis of contour measurements by confocal microscopy, in combination with data on the accumulated particle volume per unit fiber length (known accurately from a previous paper by Kasper, Schollmeier, Meyer, and Hoferer (2009). Once noticeable deposits had formed, ε was found to attain stable values between 0.80 at d_P=1.3 μm and 0.55 at d_p=5.2 μm.     

Synthesis and properties of ornithine- and lysine-based poly(N-propargylamides). Responsiveness of the helical structure to acids

Ornithine- and lysine-based novel N-propargylamides, N-α-tert-butoxycarbonyl-N-δ-fluorenylmethoxycarbonyl-l-ornithine-N′-propargylamide (1), N-α-tert-butoxycarbonyl-N-?-fluorenylmethoxycarbonyl-l-lysine-N′-propargylamide (2), N-α-fluorenylmethoxycarbonyl-N-δ-tert-butoxycarbonyl-l-ornithine-N′-propargylamide (3), and N-α-fluorenylmethoxycarbonyl-N-?-tert-butoxycarbonyl-l-lysine-N′-propargylamide (4) were synthesized and polymerized with a rhodium catalyst. Polymers with moderate molecular weights were obtained in good yields. Poly(1)-poly(4) showed strong Cotton effects in THF, whose sign and wavelength depended on the substituents. They were satisfactorily converted into the corresponding polymers [poly(1a)-poly(4a)] with free amino groups. Poly(1a) and poly(2a) also formed a helix, while poly(3a) and poly(4a) did not. Poly(1a) and poly(2a) decreased the CD intensity by the addition of m- and o-phthalic acids.     

The Anticoagulant Effect of PGI2S and tPA in Transgenic Umbilical Vein Endothelial Cells Is Linked to Up-Regulation of PKA and PKC

The selection of vascular grafts for coronary artery bypass surgery is crucial for a positive outcome. This study aimed to establish a novel line of vascular endothelial cells with a potent anticoagulant effect. A lentiviral vector was used to stably transfect human umbilical vein endothelial cells (HUVECs) with PGI2S alone (HUVEC-PGI2S) or both PGI2S and tPA (HUVEC-PGI2S-tPA). Both HUVEC-PGI2S and HUVEC-PGI2S-tPA cells over-expressing PGI2S and tPA were compared to mock-transfected cells. The enzyme-linked immuno sorbent assay (ELISAs) demonstrated that the anticoagulation components, ATIII and PLG, were up-regulated and coagulation factor FVIII was down-regulated in both cell lines. QRT-PCR and western blotting demonstrated the vasodilation and platelet disaggregation proteins PKA, PKC, and PTGIR were up-regulated in both cell lines, but MAPK expression was not altered in either cell line. However, cell viability and colony formation assays and cell cycle analysis demonstrated that both cell lines had a lower rate of cell growth and induced G1 phase arrest. HUVEC-PGI2S and HUVEC-PGI2S-tPA cells have a potent anticoagulant effect and their use in vascular heterografts may decrease the risk of thrombosis.