In this study, we address the effect of the cis-double bond in 1,2-dioleoyl-sn-glycero-3-phosphoethanolamide-N-[methoxy(polyethylene glycol)-2000, DOPE PEG2000 (DP), on the Langmuir monolayer of C18 fatty acids-namely, stearic acid (SA), oleic acid (L1), linoleic acid (L2), and linolenic acid (L3)-with the same head group but different degrees of saturation on their hydrocarbon chains. Negative values of Gibbs free energy of mixing (ΔG mix) were obtained throughout the investigated ranges of the unsaturated C18 fatty-acid (L1, L2 and L3) mixed systems, indicating that very strong attractions occurred between molecules in the monolayers. The bend and kink effects from the cis-double bond(s) in the hydrocarbon chain affected the membrane fluidity and molecular packing in the monolayers, which resulted in a greater interaction between unsaturated C18 fatty acids and DP. The most thermodynamically stable mole composition of unsaturated C18 fatty acids to DP was observed at 50:1; this ratio is suggested to be the best mole ratio and will be subsequently used to prepare DP-C18 fatty-acid nanoliposomes. The presence of cis-double bonds in both hydrocarbon chains of DOPE in DP also created an imperfection in the membrane structure of lipid-drug delivery systems, which is expected to enhance lipid-based systems for antibody conjugation and drug encapsulation.
In this work we assessed the suitability of two different lipid membranes for the simulation of a TolC protein from Salmonella enterica serovar Typhi. The TolC protein family is found in many pathogenic Gram-negative bacteria including Vibrio cholera and Pseudomonas aeruginosa and acts as an outer membrane channel for expulsion of drug and toxin from the cell. In S. typhi, the causative agent for typhoid fever, the TolC outer membrane protein is an antigen for the pathogen. The lipid environment is an important modulator of membrane protein structure and function. We evaluated the conformation of the TolC protein in the presence of DMPE and POPE bilayers using molecular dynamics simulation. The S. typhi TolC protein exhibited similar conformational dynamics to TolC and its homologues. Conformational flexibility of the protein is seen in the C-terminal, extracellular loops, and α-helical region. Despite differences in the two lipids, significant similarities in the motion of the protein in POPE and DMPE were observed, including the rotational motion of the C-terminal residues and the partially open extracellular loops. However, analysis of the trajectories demonstrated effects of hydrophobic matching of the TolC protein in the membrane, particularly in the lengthening of the lipids and subtle movements of the protein's β-barrel towards the lower leaflet in DMPE. The study exhibited the use of molecular dynamics simulation in revealing the differential effect of membrane proteins and lipids on each other. In this study, POPE is potentially a more suitable model for future simulation of the S. typhi TolC protein.
A vesicle is a microscopic particle composed of a lipid bilayer membrane that separates the inner aqueous compartment from the outer aqueous environment. Palmitoleate-palmitoleic acid vesicles were prepared and their physico-chemical properties were investigated. Moreover, mixed vesicles composed of palmitoleic acid and PEGylated lipid and/or a mixture of phospholipids were also prepared. The stabilizing effects of these double-chain lipids on the formation of palmitoleate-palmitoleic acid vesicles were studied. Stability of the vesicle suspension was examined using particle size and zeta potential at 30 °C. The magnitude of the zeta potential was relatively lower in the vesicle suspension with the presence of phospholipid. Although some of the mixed vesicles that were formed were not very stable, they displayed potential for encapsulating the active ingredient calcein and the encapsulation efficiencies of calcein were encouraging. The palmitoleate-palmitoleic acid-DPPE-PEG2000 vesicle showed the most promising stability and encapsulation efficiency.
Analysis of 300 ns (ns) molecular dynamics (MD) simulations of an adenosine A2a receptor (A2a AR) model, conducted in triplicate, in 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) and 1-palmitoyl-2-oleoylphosphatidylethanolamine (POPE) bilayers reveals significantly different protein dynamical behavior. Principal component analysis (PCA) shows that the dissimilarities stem from interhelical rather than intrahelical motions. The difference in the hydrophobic thicknesses of these simulated lipid bilayers is potentially a significant reason for the observed difference in results. The distinct lipid headgroups might also lead to different molecular interactions and hence different protein loop motions. Overall, the A2a AR shows higher mobility and flexibility in POPC as compared to POPE.
The local treatment of lung disorders such as asthma and chronic obstructive pulmonary disease via pulmonary drug delivery offers many advantages over oral or intravenous routes of administration. This is because direct deposition of a drug at the diseased site increases local drug concentrations, which improves the pulmonary receptor occupancy and reduces the overall dose required, therefore reducing the side effects that result from high drug doses. From a clinical point of view, although jet nebulizers have been used for aerosol delivery of water-soluble compounds and micronized suspensions, their use with hydrophobic drugs has been inadequate.
A Gram-staining-negative, aerobic, yellow-orange-pigmented, rod-shaped bacterium designated D-24T was isolated from seawater from sandy shoreline in Johor, Malaysia. The 16S rRNA gene sequence analysis revealed that strain D-24T is affiliated with the genus Vitellibacter. It shared more than 96 % sequence similarity with the types of some of the validly published species of the genus: Vitellibactervladivostokensis KMM 3516T (99.5 %), Vitellibactersoesokkakensis RSSK-12T (97.3 %), VitellibacterechinoideorumCC-CZW007T (96.9 %), VitellibacternionensisVBW088T (96.7 %) and Vitellibacteraestuarii JCM 15496T (96.3 %). DNA-DNA hybridization and genome-based analysis of average nucleotide identity (ANI) of strain D-24T versus V.vladivostokensisKMM 3516T exhibited values of 35.9±0.14 % and 89.26 %, respectively. Strain D-24T showed an even lower ANI value of 80.88 % with V. soesokkakensis RSSK-12T. The major menaquinone of strain D-24T was MK-6, and the predominant fatty acids were iso-C15 : 0 and iso-C17 : 0 3-OH. Strain D-24T contained major amounts of phosphatidylethanolamine, two lipids and two aminolipids, and a phosphoglycolipid that was different to that of other species of the genus Vitellibacter. The genomic DNA G+C content was 40.6 mol%. On the basis of phenotypic properties, DNA-DNA relatedness, ANI value and chemotaxonomic analyses, strain D-24T represents a novel species of the genus Vitellibacter, for which the name Vitellibacter aquimaris sp. nov. is proposed. The type strain is D-24T (=KCTC 42708T=DSM 101732T).
A bacterial strain, designated UTM-3(T), isolated from the rhizosphere soil of Artocarpus integer (cempedak) in Malaysia was studied to determine its taxonomic position. Cells were Gram-stain-negative, non-spore-forming rods, devoid of flagella and gliding motility, that formed yellow-pigmented colonies on nutrient agar and contained MK-6 as the predominant menaquinone. Comparative analysis of the 16S rRNA gene sequence of strain UTM-3(T) with those of the most closely related species showed that the strain constituted a distinct phyletic line within the genus Chryseobacterium with the highest sequence similarities to Chryseobacterium lactis NCTC 11390(T), Chryseobacterium viscerum 687B-08(T), Chryseobacterium tructae 1084-08(T), Chryseobacterium arthrosphaerae CC-VM-7(T), Chryseobacterium oncorhynchi 701B-08(T), Chryseobacterium vietnamense GIMN1.005(T), Chryseobacterium bernardetii NCTC 13530(T), Chryseobacterium nakagawai NCTC 13529(T), Chryseobacterium gallinarum LMG 27808(T), Chryseobacterium culicis R4-1A(T), Chryseobacterium flavum CW-E2(T), Chryseobacterium aquifrigidense CW9(T), Chryseobacterium ureilyticum CCUG 52546(T), Chryseobacterium indologenes NBRC 14944(T), Chryseobacterium gleum CCUG 14555(T), Chryseobacterium jejuense JS17-8(T), Chryseobacterium oranimense H8(T) and Chryseobacterium joostei LMG 18212(T). The major whole-cell fatty acids were iso-C15 : 0 and iso-C17 : 1ω9c, followed by summed feature 4 (iso-C15 : 0 2-OH and/or C16 : 1ω7t) and iso-C17 : 0 3-OH, and the polar lipid profile consisted of phosphatidylethanolamine and several unknown lipids. The DNA G+C content strain UTM-3(T) was 34.8 mol%. On the basis of the phenotypic and phylogenetic evidence, it is concluded that the isolate represents a novel species of the genus Chryseobacterium, for which the name Chryseobacterium artocarpi sp. nov. is proposed. The type strain is UTM-3(T) ( = CECT 8497(T) = KCTC 32509(T)).
The genus Roseivirga currently includes five species: Roseivirga ehrenbergii, R. echinicomitans, R. spongicola, R. marina and R. maritima. Marinicola seohaensis SW-152T was renamed as Roseivirgaseohaensis SW-152T and then reclassified again as a later heterotypic synonym of R. ehrenbergii KMM 6017T. In this study, based on average nucleotide identity and digital DNA-DNA hybridization values obtained from in silico methods, together with fatty acid analyses and biochemical tests, we propose to reclassify R. ehrenbergii SW-152 as Roseivirga seohaensis comb. nov. (type strain SW-152T=KCTC 1231T=JCM 12600T). In this work, a Gram-negative, rod-shaped, aerobic and pink-pigmented strain designated as D-25T was isolated from seawater (Desaru Beach, Johor, Malaysia). The 16S rRNA gene analysis revealed that strain D-25T was related to the genus Roseivirga. Strain D-25T was found most closely related to R. seohaensis SW-152T based on average nucleotide identity and digital DNA-DNA hybridization values, phenotypic and chemotaxonomic analyses, indicating that these strains belong to the same species. Thus, it is proposed to split the species R.oseivirga seohaensis into two novel subspecies, Roseivirga seohaensissubsp. seohaensis subsp. nov. (type strain SW-152T=KCTC 12312T=JCM 12600T) and Roseivirga seohaensissubsp. aquiponti subsp. nov. (type strain D-25T=KCTC 42709T=DSM 101709T) and to emend the description of the genus Roseivirga.
A Gram-negative, aerobic, polar-flagellated and rod-shaped, sometimes slightly curved bacterium, designated MA5T, was isolated from the gut of an abalone of the species Haliotis gigantea collected in Japan. Phylogenetic analyses based on 16S rRNA, gyrB, hsp60 and rpoB gene sequences placed strain MA5T in the genus Arcobacter in an independent phylogenetic line. Comparison of the 16S rRNA gene sequence of this strain with those of the type strains of the established Arcobacter species revealed A. nitrofigilis (95.1 %) as nearest neighbour. Strain MA5T grew optimally at 25 °C, pH 6.0 to 9.0 and in the presence of 2 to 5 % (w/v) NaCl under both aerobic and microaerobic conditions. The predominant fatty acids found were summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1 ω7c), C12 : 0 3-OH and C18 : 1 ω7c. Menaquinone-6 (MK-6) and menaquinone-7 (MK-7) were found as the major respiratory quinones. The major polar lipids detected were phosphatidylethanolamine and phosphatidylglycerol. Strain MA5T could be differentiated phenotypically from the phylogenetic closest Arcobacter species by its ability to grow on 0.05 % safranin and 0.01 % 2,3,5-triphenyl tetrazolium chloride (TTC), but not on 0.5 % NaCl. The obtained DNA G+C content of strain MA5T was 27.9 mol%. Based on the phylogenetic, chemotaxonomic and phenotypic distinctiveness of MA5T, this strain is considered to represent a novel species of the genus Arcobacter, for which the name Arcobacter haliotis sp. nov. is proposed. The type strain is MA5T (=LMG 28652T=JCM 31147T).
Four brown-alga-degrading, Gram-stain-negative, aerobic, non-flagellated, gliding and rod-shaped bacteria, designated LMG 28520T, LMG 28521, LMG 28522 and LMG 28523, were isolated from the gut of the abalone Haliotis gigantea obtained in Japan. The four isolates had identical random amplified polymorphic DNA patterns and grew optimally at 25 °C, at pH 6.0-9.0 and in the presence of 1.0-4.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences placed the isolates in the genus Formosa with Formosa algae and Formosa arctica as closest neighbours. LMG 28520T and LMG 28522 showed 100 % DNA-DNA relatedness to each other, 16-17 % towards F. algae LMG 28216T and 17-20 % towards F. arctica LMG 28318T; they could be differentiated phenotypically from these established species. The predominant fatty acids of isolates LMG 28520T and LMG 28522 were summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c), iso-C15 : 1 G and iso-C15 : 0. Isolate LMG 28520T contained menaquinone-6 (MK-6) as the major respiratory quinone and phosphatidylethanolamine, two unknown aminolipids and an unknown lipid as the major polar lipids. The DNA G+C content was 34.4 mol% for LMG 28520T and 35.5 mol% for LMG 28522. On the basis of their phylogenetic and genetic distinctiveness, and differential phenotypic properties, the four isolates are considered to represent a novel species of the genus Formosa, for which the name Formosa haliotis sp. nov. is proposed. The type strain is LMG 28520T ( = NBRC 111189T).
Inhaled corticosteroids provide unique systems for local treatment of asthma or chronic obstructive pulmonary disease. However, the use of poorly soluble drugs for nebulization has been inadequate, and many patients rely on large doses to achieve optimal control of their disease. Theoretically, nanotechnology with a sustained-release formulation may provide a favorable therapeutic index. The aim of this study was to determine the feasibility of using sterically stabilized phospholipid nanomicelles of budesonide for pulmonary delivery via nebulization.