Fabrication of patterned surface by soft lithographic technique for confinement of lipid bilayer

NASA Astrophysics Data System (ADS)

Moulick, Ranjita Ghosh; Mayer, Dirk

2018-04-01

In this paper we demonstrated that a 3D pattern can be well transferred from a silicon Master to a gold substrate using µcontact printing. In this process 1-Octadecanthiol served as an ink and printing followed by etching generated the desired pattern on the gold substrate. The prepatterned substrate was also used for lipid vesicle fusion and revealed that lipid molecules selectively bind to the gold layer.

Lipid discordance and carotid plaque in obese patients in primary prevention.

PubMed

Masson, Walter; Siniawski, Daniel; Lobo, Martín; Molinero, Graciela

2018-01-01

Obese patients with lipid discordance (non-HDL cholesterol levels 30mg/dL above the LDL-c value) may have a greater prevalence of carotid atherosclerotic plaque (CAP). Our study objectives were: 1) To assess the prevalence of lipid discordance in a primary prevention population of obese patients; 2) To investigate the association between lipid discordance and presence of CAP. Obese subjects aged >18 years (BMI ≥30kg/m 2 ) with no cardiovascular disease, diabetes, or lipid-lowering treatment from six cardiology centers were included. Lipid discordance was defined when, regardless of the LDL-c level, the non-HDL cholesterol value exceeded the LDL-c value by 30mg/dL. Presence of CAP was identified by ultrasonography. Univariate and multivariate analyses were performed to explore the association between lipid discordance and presence of CAP. The study simple consisted of 325 obese patients (57.2% men; mean age, 52.3 years). Prevalence of lipid discordance was 57.9%. CAP was found in 38.6% of patients, but the proportion was higher in subjects with lipid discordance as compared to those without this lipid pattern (44.4% vs. 30.7%, P=.01). In both the univariate (OR: 1.80; 95% CI: 1.14-2.87; P=.01) and the multivariate analysis (OR: 2.07; 95% CI: 1.22-3.54; P=.007), presence of lipid discordance was associated to an increased probability of CAP. In these obese patients, lipid discordance was associated to greater prevalence of CAP. Evaluation of obese patients with this strategy could help identify subjects with higher residual cardiovascular risk. Copyright © 2017 SEEN y SED. Publicado por Elsevier España, S.L.U. All rights reserved.

Two-Phase Contiguous Supported Lipid Bilayer Model for Membrane Rafts via Polymer Blotting and Stenciling.

PubMed

Richards, Mark J; Daniel, Susan

2017-02-07

The supported lipid bilayer has been portrayed as a useful model of the cell membrane compatible with many biophysical tools and techniques that demonstrate its appeal in learning about the basic features of the plasma membrane. However, some of its potential has yet to be realized, particularly in the area of bilayer patterning and phase/composition heterogeneity. In this work, we generate contiguous bilayer patterns as a model system that captures the general features of membrane domains and lipid rafts. Micropatterned polymer templates of two types are investigated for generating patterned bilayer formation: polymer blotting and polymer lift-off stenciling. While these approaches have been used previously to create bilayer arrays by corralling bilayers patches with various types of boundaries impenetrable to bilayer diffusion, unique to the methods presented here, there are no physical barriers to diffusion. In this work, interfaces between contiguous lipid phases define the pattern shapes, with continuity between them allowing transfer of membrane-bound biomolecules between the phases. We examine effectors of membrane domain stability including temperature and cholesterol content to investigate domain dynamics. Contiguous patterning of supported bilayers as a model of lipid rafts expands the application of the SLB to an area with current appeal and brings with it a useful toolset for characterization and analysis. These combined tools should be helpful to researchers investigating lipid raft dynamics and function and biomolecule partitioning studies. Additionally, this patterning technique may be useful for applications such as bioseparations that exploit differences in lipid phase partitioning or creation of membranes that bind species like viruses preferentially at lipid phase boundaries, to name a few.

Oil body proteins sequentially accumulate throughout seed development in Brassica napus.

PubMed

Jolivet, Pascale; Boulard, Céline; Bellamy, Annick; Valot, Benoît; d'Andréa, Sabine; Zivy, Michel; Nesi, Nathalie; Chardot, Thierry

2011-11-15

Despite the importance of seed oil bodies (OBs) as enclosed compartments for oil storage, little is known about lipid and protein accumulation in OBs during seed formation. OBs from rapeseed (Brassica napus) consist of a triacylglycerol (TAG) core surrounded by a phospholipid monolayer embedded with integral proteins which confer high stability to OBs in the mature dry seed. In the present study, we investigated lipid and protein accumulation patterns throughout seed development (from 5 to 65 days after pollination [DAP]) both in the whole seed and in purified OBs. Deposition of the major proteins (oleosins, caleosins and steroleosins) into OBs was assessed through (i) gene expression pattern, (ii) proteomics analysis, and (iii) protein immunodetection. For the first time, a sequential deposition of integral OB proteins was established. Accumulation of oleosins and caleosins was observed starting from early stages of seed development (12-17 DAP), while steroleosins accumulated later (~25 DAP) onwards. Copyright © 2011 Elsevier GmbH. All rights reserved.

Dynamic patterns in a supported lipid bilayer driven by standing surface acoustic waves.

PubMed

Hennig, Martin; Neumann, Jürgen; Wixforth, Achim; Rädler, Joachim O; Schneider, Matthias F

2009-11-07

In the past decades supported lipid bilayers (SLBs) have been an important tool in order to study the physical properties of biological membranes and cells. So far, controlled manipulation of SLBs is very limited. Here we present a new technology to create lateral patterns in lipid membranes controllable in both space and time. Surface acoustic waves (SAWs) are used to generate lateral standing waves on a piezoelectric substrate which create local "traps" in the lipid bilayer and lead to a lateral modulation in lipid concentration. We demonstrate that pattern formation is reversible and does not affect the integrity of the lipid bilayer as shown by extracting the diffusion constant of fluid membranes. The described method could possibly be used to design switchable interfaces for the lateral transport and organization of membrane bound macromolecules to create dynamic bioarrays and control biofilm formation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryu, Yong -Sang; Wittenberg, Nathan J.; Suh, Jeng -Hun

We show that the selective localization of cholesterol-rich domains and associated ganglioside receptors prefer to occur in the monolayer across continuous monolayer-bilayer junctions (MBJs) in supported lipid membranes. For the MBJs, glass substrates were patterned with poly(dimethylsiloxane) (PDMS) oligomers by thermally-assisted contact printing, leaving behind 3 nm-thick PDMS patterns. The hydrophobicity of the transferred PDMS patterns was precisely tuned by the stamping temperature. Lipid monolayers were formed on the PDMS patterned surface while lipid bilayers were on the bare glass surface. Due to the continuity of the lipid membranes over the MBJs, essentially free diffusion of lipids was allowed betweenmore » the monolayer on the PDMS surface and the upper leaflet of the bilayer on the glass substrate. The preferential localization of sphingomyelin, ganglioside GM1 and cholesterol in the monolayer region enabled to develop raft microdomains through coarsening of nanorafts. Furthermore, our methodology provides a simple and effective scheme of non-disruptive manipulation of the chemical landscape associated with lipid phase separations, which leads to more sophisticated applications in biosensors and as cell culture substrates.« less

Dietary pattern as identified by factorial analysis and its association with lipid profile and fasting plasma glucose among Iranian individuals with spinal cord injury.

PubMed

Sabour, Hadis; Soltani, Zahra; Latifi, Sahar; Javidan, Abbas Norouzi

2016-07-01

Plasma lipids (triglyceride (TG), total cholesterol (TC), high-density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C)) may be associated with dietary intakes. The purpose of this study was to identify the most common food patterns among Iranian persons with spinal cord injury (SCI) and investigate their associations with lipid profile. Cross-sectional. Tertiary rehabilitation center. Referred individuals to Brain and Spinal Injury Research Center (BASIR) from 2011 to 2014. Dietary intakes were assessed by 24-hour dietary recall interviews in three non-consecutive days. Principal component analysis (PCA) was used to identify dietary patterns. Total of 100 persons (83 male and 17 female) entered the study. Four food patterns were detected. The most common dietary pattern (Pattern 1) included processed meat, sweets desserts and soft drink and was similar to 'Western' food pattern described previously. Pattern 1 was related to higher levels of TC and LDL-C (r = 0.09; P = 0.04 and r = 0.11; P = 0.03 for TC and LDL-C, respectively) only in male participants. Pattern 2 which included tea, nuts, vegetable oil and sugars had a positive association with TC level (r = 0.11; P = 0.02) again in male participants. Pattern 3 which represented a healthy food pattern showed no significant influence on lipid profiles. In this study, the four most common dietary patterns among Iranian individuals with SCI have been identified. Western food pattern was the most common diet and was associated with increased TC and LDL-C. The healthy food pattern, in which the major source of calories was protein, was not associated with variance in lipid profile.

Influence of chain rigidity on the conformation of model lipid membranes in the presence of cylindrical nanoparticle inclusions

NASA Astrophysics Data System (ADS)

Diloreto, Chris; Wickham, Robert

2012-02-01

We employ real-space self-consistent field theory to study the conformation of model lipid membranes in the presence of solvent and cylindrical nanoparticle inclusions (''peptides''). Whereas it is common to employ a polymeric Gaussian chain model for the lipids, here we model the lipids as persistent, worm-like chains. Our motivation is to develop a more realistic field theory to describe the action of pore-forming anti-microbial peptides that disrupt the bacterial cell membrane. We employ operator-splitting and a pseudo-spectral algorithm, using SpharmonicKit for the chain tangent degrees of freedom, to solve for the worm-like chain propagator. The peptides, modelled using a mask function, have a surface patterned with hydrophobic and hydrophillic patches, but no charge. We examine the role chain rigidity plays in the hydrophobic mismatch, the membrane-mediated interaction between two peptides, the size and structure of pores formed by peptide aggregates, and the free-energy barrier for peptide insertion into the membrane. Our results suggest that chain rigidity influences both the pore structure and the mechanism of pore formation.

Polar lipid composition of a new halobacterium

NASA Technical Reports Server (NTRS)

Tindall, B. J.; Tomlinson, G. A.; Hochstein, L. I.

1987-01-01

Investigations of the polar lipid composition of a new aerobic, extremely halophilic aracheabacterium capable of nitrate reduction have shown that this organism contains two previously unknown phospholycolipids derived from diphytanyl glycerol diethers. Comparison of the lipid pattern from this new isolate with other known strains indicate that this organism is novel. On the basis of the unique polar lipid pattern it can be concluded that this organism represents a new taxon, at least at the species level.

Bayesian test for colocalisation between pairs of genetic association studies using summary statistics.

PubMed

Giambartolomei, Claudia; Vukcevic, Damjan; Schadt, Eric E; Franke, Lude; Hingorani, Aroon D; Wallace, Chris; Plagnol, Vincent

2014-05-01

Genetic association studies, in particular the genome-wide association study (GWAS) design, have provided a wealth of novel insights into the aetiology of a wide range of human diseases and traits, in particular cardiovascular diseases and lipid biomarkers. The next challenge consists of understanding the molecular basis of these associations. The integration of multiple association datasets, including gene expression datasets, can contribute to this goal. We have developed a novel statistical methodology to assess whether two association signals are consistent with a shared causal variant. An application is the integration of disease scans with expression quantitative trait locus (eQTL) studies, but any pair of GWAS datasets can be integrated in this framework. We demonstrate the value of the approach by re-analysing a gene expression dataset in 966 liver samples with a published meta-analysis of lipid traits including >100,000 individuals of European ancestry. Combining all lipid biomarkers, our re-analysis supported 26 out of 38 reported colocalisation results with eQTLs and identified 14 new colocalisation results, hence highlighting the value of a formal statistical test. In three cases of reported eQTL-lipid pairs (SYPL2, IFT172, TBKBP1) for which our analysis suggests that the eQTL pattern is not consistent with the lipid association, we identify alternative colocalisation results with SORT1, GCKR, and KPNB1, indicating that these genes are more likely to be causal in these genomic intervals. A key feature of the method is the ability to derive the output statistics from single SNP summary statistics, hence making it possible to perform systematic meta-analysis type comparisons across multiple GWAS datasets (implemented online at http://coloc.cs.ucl.ac.uk/coloc/). Our methodology provides information about candidate causal genes in associated intervals and has direct implications for the understanding of complex diseases as well as the design of drugs to target disease pathways.

Inhibition of lipid A-mediated type I interferon induction by bactericidal/permeability-increasing protein (BPI).

PubMed

Azuma, Masahiro; Matsuo, Aya; Fujimoto, Yukari; Fukase, Koichi; Hazeki, Kaoru; Hazeki, Osamu; Matsumoto, Misako; Seya, Tsukasa

2007-03-09

Lipopolysaccharide (LPS), a major constituent of the outer membrane of gram-negative bacteria, consists of polysaccharides and a lipid structure named lipid A. Lipid A is a typical microbial pattern molecule that serves as a ligand for Toll-like receptor 4 (TLR4). TLR4 signals the presence of lipid A to recruit adaptor molecules and induces cytokines and type I interferon (IFN) by activating transcription factor, NF-kappaB or IRF-3. Here we showed that chemically synthesized TLR4-agonistic lipid A analogues but not antagonistic lipid A activate IFN-beta promoter in TLR4-expressing HEK293 cells. The amplitude of IFN-beta promoter activation was in parallel with that of NF-kappaB. LPS-binding protein (LBP) was required for efficient IFN-beta induction in this system, and this LBP activity was antagonized by bactericidal/permeability-increasing protein (BPI). Thus, we first show that BPI blocks the TLR4 responses by exogenous administration of BPI to lipid A-sensitive cells. Although the functional mechanism whereby extra-cellular BPI modulates the intra-cellular signal pathways selected by the TLR adaptors, MyD88 and TICAM-1 (TRIF), remains unknown, we infer that the lipid A portion of LPS participates in LBP-amplified IFN-beta induction and that BPI binding to LPS leads to inhibition of the activation of NF-kappaB and IFN-beta by LPS or agonistic lipid A via TLR4 in an extrinsic mode. BPI may serve as a therapeutic potential against endotoxin shock by acting as a regulator for the MyD88- and TICAM-1 pathways in the LPS-TLR4 signaling.

Modification of structure and pattern of lipid monolayer on water and solid surfaces in presence of globular protein

NASA Astrophysics Data System (ADS)

Sah, Bijay Kumar; Kundu, Sarathi

2017-05-01

Langmuir monolayers of phospholipids at the air-water interface are well-established model systems for mimicking biological membranes and hence are useful for studying lipid-protein interactions. In the present work, phases and phase transformations occurring in the lipid (DMPA) monolayer in the presence of globular protein (BSA) at neutral subphase pH (≈7.0) are highlighted and the corresponding in-plane pattern and morphology are explored from the surface pressure (π) - specific molecular area (A) isotherm, Brewster angle microscopy (BAM) and atomic force microscopy (AFM) both at air-water and air-solid interfaces. Films of pure lipid and lipid-protein complexes are deposited on solid surfaces by Langmuir-Blodgett method. Due to the presence of BSA molecules, phases and domain pattern changes in comparison with that of the pure DMPA. Moreover, accumulations of globular proteins in between lipid domains are also visible through BAM. AFM shows that the mixed film has relatively bigger globular-like morphology in comparison with that of pure DMPA domains. Combination of electrostatic and hydrophobic interactions between protein and lipid are responsible for such modifications.

Lipid profiles of detergent resistant fractions of the plasma membrane in oat and rye in association with cold acclimation and freezing tolerance.

PubMed

Takahashi, Daisuke; Imai, Hiroyuki; Kawamura, Yukio; Uemura, Matsuo

2016-04-01

Cold acclimation (CA) results in alteration of the plasma membrane (PM) lipid composition in plants, which plays a crucial role in the acquisition of freezing tolerance via membrane stabilization. Recent studies have indicated that PM structure is consistent with the fluid mosaic model but is laterally non-homogenous and contains microdomains enriched in sterols, sphingolipids and specific proteins. In plant cells, the function of these microdomains in relation to CA and freezing tolerance is not yet fully understood. The present study aimed to investigate the lipid compositions of detergent resistant fractions of the PM (DRM) which are considered to represent microdomains. They were prepared from leaves of low-freezing tolerant oat and high-freezing tolerant rye. The DRMs contained higher proportions of sterols, sphingolipids and saturated phospholipids than the PM. In particular, one of the sterol lipid classes, acylated sterylglycoside, was the predominant sterol in oat DRM while rye DRM contained free sterol as the major sterol. Oat and rye showed different patterns (or changes) of sterols and 2-hydroxy fatty acids of sphingolipids of DRM lipids during CA. Taken together, these results suggest that CA-induced changes of lipid classes and molecular species in DRMs are associated with changes in the thermodynamic properties and physiological functions of microdomains during CA and hence, influence plant freezing tolerance. Copyright © 2016 Elsevier Inc. All rights reserved.

Lipid remodelling in the reef-building honeycomb worm, Sabellaria alveolata, reflects acclimation and local adaptation to temperature

PubMed Central

Muir, Anna P.; Nunes, Flavia L. D.; Dubois, Stanislas F.; Pernet, Fabrice

2016-01-01

Acclimation and adaptation, which are key to species survival in a changing climate, can be observed in terms of membrane lipid composition. Remodelling membrane lipids, via homeoviscous adaptation (HVA), counteracts membrane dysfunction due to temperature in poikilotherms. In order to assess the potential for acclimation and adaptation in the honeycomb worm, Sabellaria alveolata, a reef-building polychaete that supports high biodiversity, we carried out common-garden experiments using individuals from along its latitudinal range. Individuals were exposed to a stepwise temperature increase from 15 °C to 25 °C and membrane lipid composition assessed. Our results suggest that S. alveolata was able to acclimate to higher temperatures, as observed by a decrease in unsaturation index and 20:5n-3. However, over the long-term at 25 °C, lipid composition patterns are not consistent with HVA expectations and suggest a stress response. Furthermore, unsaturation index of individuals from the two coldest sites were higher than those from the two warmest sites, with individuals from the thermally intermediate site being in-between, likely reflecting local adaptation to temperature. Therefore, lipid remodelling appears limited at the highest temperatures in S. alveolata, suggesting that individuals inhabiting warm environments may be close to their upper thermal tolerance limits and at risk in a changing climate. PMID:27762300

HIP1 and HIP1r stabilize receptor tyrosine kinases and bind 3-phosphoinositides via epsin N-terminal homology domains.

PubMed

Hyun, Teresa S; Rao, Dinesh S; Saint-Dic, Djenann; Michael, L Evan; Kumar, Priti D; Bradley, Sarah V; Mizukami, Ikuko F; Oravecz-Wilson, Katherine I; Ross, Theodora S

2004-04-02

Huntingtin-interacting protein 1-related (HIP1r) is the only known mammalian relative of huntingtin-interacting protein 1 (HIP1), a protein that transforms fibroblasts via undefined mechanisms. Here we demonstrate that both HIP1r and HIP1 bind inositol lipids via their epsin N-terminal homology (ENTH) domains. In contrast to other ENTH domain-containing proteins, lipid binding is preferential to the 3-phosphate-containing inositol lipids, phosphatidylinositol 3,4-bisphosphate and phosphatidylinositol 3,5-bisphosphate. Furthermore, the HIP1r ENTH domain, like that of HIP1, is necessary for lipid binding, and expression of an ENTH domain-deletion mutant, HIP1r/deltaE, induces apoptosis. Consistent with the ability of HIP1r and HIP1 to affect cell survival, full-length HIP1 and HIP1r stabilize pools of growth factor receptors by prolonging their half-life following ligand-induced endocytosis. Although HIP1r and HIP1 display only a partially overlapping pattern of protein interactions, these data suggest that both proteins share a functional homology by binding 3-phosphorylated inositol lipids and stabilizing receptor tyrosine kinases in a fashion that may contribute to their ability to alter cell growth and survival.

Strong Static Magnetic Fields Increase the Gel Signal in Partially Hydrated DPPC/DMPC Membranes.

PubMed

Tang, Jennifer; Alsop, Richard J; Schmalzl, Karin; Epand, Richard M; Rheinstädter, Maikel C

2015-09-29

NIt was recently reported that static magnetic fields increase lipid order in the hydrophobic membrane core of dehydrated native plant plasma membranes [Poinapen, Soft Matter 9:6804-6813, 2013]. As plasma membranes are multicomponent, highly complex structures, in order to elucidate the origin of this effect, we prepared model membranes consisting of a lipid species with low and high melting temperature. By controlling the temperature, bilayers coexisting of small gel and fluid domains were prepared as a basic model for the plasma membrane core. We studied molecular order in mixed lipid membranes made of dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) using neutron diffraction in the presence of strong static magnetic fields up to 3.5 T. The contribution of the hydrophobic membrane core was highlighted through deuterium labeling the lipid acyl chains. There was no observable effect on lipid organization in fluid or gel domains at high hydration of the membranes. However, lipid order was found to be enhanced at a reduced relative humidity of 43%: a magnetic field of 3.5 T led to an increase of the gel signal in the diffraction patterns of 5%. While all biological materials have weak diamagnetic properties, the corresponding energy is too small to compete against thermal disorder or viscous effects in the case of lipid molecules. We tentatively propose that the interaction between the fatty acid chains' electric moment and the external magnetic field is driving the lipid tails in the hydrophobic membrane core into a better ordered state.

Physiological and biochemical changes during the larval development of a brachyuran crab reared under constant conditions in the laboratory

NASA Astrophysics Data System (ADS)

Anger, K.; Harms, J.; Püschel, C.; Seeger, B.

1989-06-01

Larvae of the spider crab Hyas araneus were reared in the laboratory at constant conditions (12°C; 32‰S), and their feeding rate ( F), oxygen consumption ( R), nitrogen excretion ( U), and growth were measured in regular intervals of time during development from hatching to metamorphosis. Growth was measured as dry weight ( W), carbon ( C), nitrogen ( N), hydrogen ( H) protein, and lipid. All these physiological and biochemical traits revealed significant changes both from instar to instar and during individual larval moult cycles. Average F was low in the zoea I, reached a maximum in the zoea II, and decreased again in the megalopa. In the zoeal instars, it showed a bell-shaped pattern, with a maximum in the middle (zoea I) or during the first half of the moult cycle (zoea II). Maximum F in the megalopa was observed still earlier, during postmoult. Respiration ( R) increased in the zoeal instars as a linear function of time, whereas it showed a sinusoidal pattern in the megalopa. These findings on variation in F and R during larval development confirm results obtained in previous studies on H. araneus and other decapod species. Excretion ( U) was measured for the first time with a high temporal resolution in crab larvae. It showed in all three larval instars a bell-shaped variation pattern, with a maximum near the middle of the moult cycle, and significantly increasing average values from instar to instar. The atomic O/N ratio followed an inverse pattern, suggesting a maximum utilization of protein as a metabolic substrate during intermoult. Growth data from the present study and from a number of previous studies were compiled, showing consistency of growth patterns, but a considerable degree of variability between larvae from different hatches reared under identical conditions. The data show the following consistent tendencies: during the first part of each larval moult cycle (in postmoult, partly in intermoult), lipids are accumulated at a higher rate than protein, whereas an inverse growth patterns is typical of the later (premoult) stages. These two different growth phases are interpreted as periods dominated by reserve accumulation in the hepatopancreas, and epidermal growth and reconstruction (morphogenesis), respectively. Differences between individual larval instars in average biochemical composition and growth patterns may be related to different strategies: the zoeal instars and the early megalopa are pelagic feeding stages, accumulating energy reserves (principally lipids) necessary for the completion of larval development, whereas the later (premoult) megalopa is a semibenthic settling stage that converts a significant part of this energy to epidermal protein. The megalopa shifts in behaviour and energy partitioning from intense feeding activity and body growth to habitat selection and morphogenesis, preparing itself for metamorphosis, i.e. it shows an increasing degree of lecithotrophy. Data from numerous parallel elemental and biochemical analyses are compiled to show quantitative relationships between W, C, N, H, lipid, and protein. These regressions may be used as empirical conversion equations for estimates of single chemical components in larval Hyas araneus, and, possibly, other decapods.

Eating patterns and lipid levels in older adolescent girls.

PubMed

Bradlee, M L; Singer, M R; Daniels, S R; Moore, L L

2013-03-01

Few studies have evaluated the effects of food-based eating patterns on adolescent lipid levels. This study examines whether usual adolescent eating patterns (ages 9-17 years) predict lipid levels at 18-20 years of age. This study uses previously collected data from the longitudinal NHLBI Growth and Health Study in which 2379 girls were enrolled at ages 9-10 years and followed for ten years. Food-based eating patterns were derived from multiple 3-day diet records. After adjusting for age, race, socioeconomic status, height, physical activity, and television viewing, girls with higher intakes of dairy, fruit and non-starchy vegetables had about a 40-50% reduced risk an LDL-C ≥ 170 mg/dL and non-HDL-C ≥ 145 mg/dL. Diets characterized by higher intakes of dairy and whole grains had similar benefits on TC and LDL-C. Girls consuming more fruits and non-starchy vegetables as well as more whole grains were much less likely to have high-risk lipid levels. Lean meat, poultry and fish when consumed in the context of other healthy eating patterns had no adverse effects on lipid levels in late adolescence. In fact when consumed with higher amounts of fruit and non-starchy vegetables, lean meat, poultry and fish had beneficial effects on HDL. Finally, dietary patterns that included more whole grains tended to be associated with lower TG levels. Healthy childhood eating patterns characterized by higher intakes of a variety of fruits, vegetables, whole grains, dairy, lean meat, poultry and fish are important modifiable predictors of lipid levels in late adolescence. Copyright © 2011 Elsevier B.V. All rights reserved.

Patterns of variation in clutch sizes in a guild of temperate-nesting dabbling ducks

USGS Publications Warehouse

Krapu, G.L.; Reynolds, R.E.; Sargeant, G.A.; Renner, R.W.

2004-01-01

Clutch sizes of temperate-nesting dabbling ducks vary widely within and between years. Biologists have long been interested in why such patterns exist but have had difficulty separating intrinsic effects from environmental influences. In an attempt to gain greater insight into the roles of intrinsic and environmental influences on clutch sizes of dabbling ducks, we compared clutch-size patterns of mallard, northern pintail, gadwall, northern shoveler, and blue-winged teal in North Dakota and South Dakota over a 3-year period. The study was conducted during 1993-1995 when wetland habitat conditions were exceptionally consistent within time intervals but varied widely from the onset to the end of the study. We found that clutch sizes of gadwall and blue-winged teal were significantly smaller at the onset of nesting in 1993, when water conditions remained relatively poor following a 5-year drought (1988-1992), and pintail clutch sizes were larger late in the breeding season in 1993 after wetland conditions became exceptionally productive following heavy rains in late May and June. These findings were associated with gadwall and teal relying primarily on nutrients acquired on the breeding grounds to produce early clutches, and pintails using an exceptionally high proportion of their body lipids to produce early clutches, making this species highly dependent on abundant local sources of lipids for clutches produced later. Mallard, pintail, and shoveler rely largely on endogenous lipids carried to the breeding grounds to produce early clutches, and at least in the years of study, clutch sizes exhibited minimal variation at the onset of nesting. Our findings, when examined in context with existing information, suggest that interspecific variation in clutch sizes results from innate differences in several traits -- including body size, diet, timing of lipid acquisition, and nesting-- that affect the amount of lipid available for egg production. Annual differences in clutch sizes of all five species were not significant when effects of annual variation in nest initiation dates was accounted for, reflecting the key role of environmental influences on intraspecific variation among years.

Structural characterization of the lipid A region of Aeromonas salmonicida subsp. salmonicida lipopolysaccharide.

PubMed

Wang, Zhan; Li, Jianjun; Altman, Eleonora

2006-12-11

The lipid A components of Aeromonas salmonicida subsp. salmonicida from strains A449, 80204-1 and an in vivo rough isolate were isolated by mild acid hydrolysis of the lipopolysaccharide. Structural studies carried out by a combination of fatty acid, electrospray ionization-mass spectrometry and nuclear magnetic resonance analyses confirmed that the structure of lipid A was conserved among different isolates of A. salmonicida subsp. salmonicida. All analyzed strains contained three major lipid A molecules differing in acylation patterns corresponding to tetra-, penta- and hexaacylated lipid A species and comprising 4'-monophosphorylated beta-2-amino-2-deoxy-d-glucopyranose-(1-->6)-2-amino-2-deoxy-d-glucopyranose disaccharide, where the reducing end 2-amino-2-deoxy-d-glucose was present primarily in the alpha-pyranose form. Electrospray ionization-tandem mass spectrometry fragment pattern analysis, including investigation of the inner-ring fragmentation, allowed the localization of fatty acyl residues on the disaccharide backbone of lipid A. The tetraacylated lipid A structure containing 3-(dodecanoyloxy)tetradecanoic acid at N-2',3-hydroxytetradecanoic acid at N-2 and 3-hydroxytetradecanoic acid at O-3, respectively, was found. The pentaacyl lipid A molecule had a similar fatty acid distribution pattern and, additionally, carried 3-hydroxytetradecanoic acid at O-3'. In the hexaacylated lipid A structure, 3-hydroxytetradecanoic acid at O-3' was esterified with a secondary 9-hexadecenoic acid. Interestingly, lipid A of the in vivo rough isolate contained predominantly tetra- and pentaacylated lipid A species suggesting that the presence of the hexaacyl lipid A was associated with the smooth-form lipopolysaccharide.

[Assessment of lipid layer thickness of tear film in the diagnosis of dry-eye syndrome in children after the hematopoietic stem cell transplantation].

PubMed

Kurpińska, Małgorzata; Gorczyńska, Ewa; Owoc-Lempach, Joanna; Bernacka, Aleksandra; Misiuk-Hojło, Marta; Chybicka, Alicja

2011-01-01

Dry eye syndrome (DES), also known as keratoconjunctivitis sicca (KCS) is recognized as the most frequent ocular complication after allogeneic stem cell transplantation (allo-SCT). KCS can appear either due to insufficient tear production or excessive tear evaporation, both resulting in tears hyperosmolarity that leads to ocular damage. The evaporation rate and better film stability is determined primarily by the status of the lipid layer. Observation and classification of tear film lipid layer interference patterns in normal and dry eyes in patients after allogeneic stem cell transplantation with a follow-up time of 6 months-5 years (median 26.54 months). Investigation of the relation between the lipid layer interference patterns in normal and dry eyes and the results of other dry eye examinations and complaints. Relation between DES and conditioning regimes, including total body irradiation and high-dose chemotherapy, immunosuppressive drugs, the time after allogeneic stem cell transplantation and chronic graft-versus-host disease. Precorneal tears lipid layer interference patterns, were examined in 114 eyes in treatment group with the Tearscope-plus. Patient with dry eye were identified on the basis of Schirmer test scores and/or tear breakup time, and positive lissamine and/or fluorescein staining. 42 of 114 eyes (36.8%) developed DES after allo-SCT A significant correlation between thickness of lipid layer and BUT, Schirmer test, lissamine green and fluorescein staining was found in the treatment group. A significant association was found between present chronic GVHD and DES in children. DES was not associated with TBI, corticosteroids, immunosuppressive drugs and the time in the present study. Tears lipid layer interference patterns are highly correlated with the diagnosis of DES. Tears lipid layer interference patterns ( noninvasive method), can be used to diagnose early DES in children after allo-SCT. Chronic GVHD play a major role in development of DES. dry eye syndrome, graft versus host disease, stem cell transplantation.

PPAR-γ activation by Tityus serrulatus venom regulates lipid body formation and lipid mediator production.

PubMed

Zoccal, Karina Furlani; Paula-Silva, Francisco Wanderley Garcia; Bitencourt, Claudia da Silva; Sorgi, Carlos Artério; Bordon, Karla de Castro Figueiredo; Arantes, Eliane Candiani; Faccioli, Lúcia Helena

2015-01-01

Tityus serrulatus venom (TsV) consists of numerous peptides with different physiological and pharmacological activities. Studies have shown that scorpion venom increases pro-inflammatory cytokine production, contributing to immunological imbalance, multiple organ dysfunction, and patient death. We have previously demonstrated that TsV is a venom-associated molecular pattern (VAMP) recognized by TLRs inducing intense inflammatory reaction through the production of pro-inflammatory cytokines and arachidonic acid-derived lipid mediators prostaglandin (PG)E2 and leukotriene (LT)B4. Lipid bodies (LBs) are potential sites for eicosanoid production by inflammatory cells. Moreover, recent studies have shown that the peroxisome proliferator-activated receptor gamma (PPAR-γ) is implicated in LB formation and acts as an important modulator of lipid metabolism during inflammation. In this study, we used murine macrophages to evaluate whether the LB formation induced by TsV after TLR recognition correlates with lipid mediator generation by macrophages and if it occurs through PPAR-γ activation. We demonstrate that TsV acts through TLR2 and TLR4 stimulation and PPAR-γ activation to induce LB formation and generation of PGE2 and LTB4. Our data also show that PPAR-γ negatively regulates the pro-inflammatory NF-κB transcription factor. Based on these results, we suggest that during envenomation, LBs constitute functional organelles for lipid mediator production through signaling pathways that depend on cell surface and nuclear receptors. These findings point to the inflammatory mechanisms that might also be triggered during human envenomation by TsV. Copyright © 2014 Elsevier Ltd. All rights reserved.

Proteomic and Lipidomic Analysis of Nanoparticle Corona upon Contact with Lung Surfactant Reveals Differences in Protein, but Not Lipid Composition.

PubMed

Raesch, Simon Sebastian; Tenzer, Stefan; Storck, Wiebke; Rurainski, Alexander; Selzer, Dominik; Ruge, Christian Arnold; Perez-Gil, Jesus; Schaefer, Ulrich Friedrich; Lehr, Claus-Michael

2015-12-22

Pulmonary surfactant (PS) constitutes the first line of host defense in the deep lung. Because of its high content of phospholipids and surfactant specific proteins, the interaction of inhaled nanoparticles (NPs) with the pulmonary surfactant layer is likely to form a corona that is different to the one formed in plasma. Here we present a detailed lipidomic and proteomic analysis of NP corona formation using native porcine surfactant as a model. We analyzed the adsorbed biomolecules in the corona of three NP with different surface properties (PEG-, PLGA-, and Lipid-NP) after incubation with native porcine surfactant. Using label-free shotgun analysis for protein and LC-MS for lipid analysis, we quantitatively determined the corona composition. Our results show a conserved lipid composition in the coronas of all investigated NPs regardless of their surface properties, with only hydrophilic PEG-NPs adsorbing fewer lipids in total. In contrast, the analyzed NP displayed a marked difference in the protein corona, consisting of up to 417 different proteins. Among the proteins showing significant differences between the NP coronas, there was a striking prevalence of molecules with a notoriously high lipid and surface binding, such as, e.g., SP-A, SP-D, DMBT1. Our data indicate that the selective adsorption of proteins mediates the relatively similar lipid pattern in the coronas of different NPs. On the basis of our lipidomic and proteomic analysis, we provide a detailed set of quantitative data on the composition of the surfactant corona formed upon NP inhalation, which is unique and markedly different to the plasma corona.

Vertical distribution of lipids, fatty acids and organochlorine contaminants in the blubber of southern hemisphere humpback whales (Megaptera novaeangliae).

PubMed

Waugh, Courtney A; Nichols, Peter D; Schlabach, Martin; Noad, Michael; Bengtson Nash, Susan

2014-03-01

Persistent organic pollutants (POPs), such as toxic lipophilic organochlorine (OC) compounds, accumulate in the blubber tissue of marine mammals. Toxicological sampling methods most frequently target only the superficial blubber layer. Vertical distribution of these contaminants through the blubber mantle may, however, not be homogenous and could reflect any dissemination of lipids and fatty acids (FAs). It is therefore critical to assess stratification patterns in a species of interest as a quality control measure for interpretation of toxicological data. Here, we analysed and compared the distribution of lipids, FAs, and OCs in the outermost and innermost blubber layer of southern hemisphere humpback whales. FA stratification was evident for short-chain (≤18) monounsaturated fatty acids (SC-MUFA), which were concentrated in the outer layer, consistent with the thermoregulatory role of this blubber layer. This stratification was, however, not reflected in OC distribution, which was similar in the inner and outer blubber layers of male humpback whales. By comparison, a noticeable gradient in total blubber lipid from the outer to the inner layer was observed in two lactating females, which coincided with higher lipid normalised contaminant levels in the inner layer. This study contains the most comprehensive assessment of humpback whale blubber stratification to date, however, further investigation of biological and ecological influencing factors is required. Copyright © 2013 Elsevier Ltd. All rights reserved.

Interaction between VEGF receptor-2 gene polymorphisms and dietary patterns on blood glucose and lipid levels in Chinese Malaysian adults.

PubMed

Yap, Roseline Wai Kuan; Shidoji, Yoshihiro; Hon, Wei Min; Masaki, Motofumi

2011-01-01

The prevalence of lifestyle-related chronic diseases is increasing and gene-diet interaction studies are limited among the Malaysian population. This study was conducted to evaluate the association and interaction effects of vascular endothelial growth factor receptor-2(VEGFR2) gene polymorphisms and dietary patterns on anthropometric and biochemical risk factors of chronic diseases in 179 Chinese Malaysian adults. Genotyping of rs1870377 and rs2071559 was performed by real-time PCR using TaqMan probes. Dietary patterns were constructed from the food frequency questionnaire using factor analysis. Anthropometric measurements: body mass index (BMI), systolic and diastolic blood pressure and biomarkers: blood glucose, glycated hemoglobin A1c (HbA1c) and lipids were obtained. Two dietary patterns: 'Balanced diet' and 'Meat, rice and noodles diet' (MRND) were extracted. MRND was associated with higher BMI, blood pressure, blood glucose and lipids, while T alleles in both rs1870377 and rs2071559 were associated with higher blood lipids (p < 0.05). The interaction of MRND and rs1870377 had a borderline effect on blood HbA1c after adjusting for confounders (p = 0.057). A dietary pattern of MRND and VEGFR2 gene polymorphisms were both associated with increased health risks of lifestyle-related chronic diseases particularly blood glucose and lipid levels in Chinese Malaysian adults. Copyright © 2012 S. Karger AG, Basel.

Lipid accumulation and biosynthesis genes response of the oleaginous Chlorella pyrenoidosa under three nutrition stressors

PubMed Central

2014-01-01

Background Microalgae can accumulate considerable amounts of lipids under different nutrient-deficient conditions, making them as one of the most promising sustainable sources for biofuel production. These inducible processes provide a powerful experimental basis for fully understanding the mechanisms of physiological acclimation, lipid hyperaccumulation and gene expression in algae. In this study, three nutrient-deficiency strategies, viz nitrogen-, phosphorus- and iron-deficiency were applied to trigger the lipid hyperaccumulation in an oleaginous Chlorella pyrenoidosa. Regular patterns of growth characteristics, lipid accumulation, physiological parameters, as well as the expression patterns of lipid biosynthesis-related genes were fully analyzed and compared. Results Our results showed that all the nutrient stress conditions could enhance the lipid content considerably compared with the control. The total lipid and neutral lipid contents exhibit the most marked increment under nitrogen deficiency, achieving 50.32% and 34.29% of dry cell weight at the end of cultivation, respectively. Both photosynthesis indicators and reactive oxygen species parameters reveal that physiological stress turned up when exposed to nutrient depletions. Time-course transcript patterns of lipid biosynthesis-related genes showed that diverse expression dynamics probably contributes to the different lipidic phenotypes under stress conditions. By analyzing the correlation between lipid content and gene expression level, we pinpoint several genes viz. rbsL, me g6562, accA, accD, dgat g2354, dgat g3280 and dgat g7063, which encode corresponding enzymes or subunits of malic enzyme, ACCase and diacylglycerol acyltransferase in the de novo TAG biosynthesis pathway, are highly related to lipid accumulation and might be exploited as target genes for genetic modification. Conclusion This study provided us not only a comprehensive picture of adaptive mechanisms from physiological perspective, but also a number of targeted genes that can be used for a systematic metabolic engineering. Besides, our results also represented the feasibility of lipid production through trophic transition cultivation modes, throwing light on a two-stage microalgal lipid production strategy with which heterotrophy stage provides sufficient robust seed and nitrogen-starvation photoautotrophy stage enhances the overall lipid productivity. PMID:24479413

Metals and lipid oxidation. Contemporary issues.

PubMed

Schaich, K M

1992-03-01

Lipid oxidation is now recognized to be a critically important reaction in physiological and toxicological processes as well as in food products. This provides compelling reasons to understand what causes lipid oxidation in order to be able to prevent or control the reactions. Redox-active metals are major factors catalyzing lipid oxidation in biological systems. Classical mechanisms of direct electron transfer to double bonds by higher valence metals and of reduction of hydroperoxides by lower valence metals do not always account for patterns of metal catalysis of lipid oxidation in multiphasic or compartmentalized biological systems. To explain why oxidation kinetics, mechanisms, and products in molecular environments which are both chemically and physically complex often do not follow classical patterns predicted by model system studies, increased consideration must be given to five contemporary issues regarding metal catalysis of lipid oxidation: hypervalent non-heme iron or iron-oxygen complexes, heme catalysis mechanism(s), compartmentalization of reactions and lipid phase reactions of metals, effects of metals on product mixes, and factors affecting the mode of metal catalytic action.

FRAP to Characterize Molecular Diffusion and Interaction in Various Membrane Environments.

PubMed

Pincet, Frédéric; Adrien, Vladimir; Yang, Rong; Delacotte, Jérôme; Rothman, James E; Urbach, Wladimir; Tareste, David

2016-01-01

Fluorescence recovery after photobleaching (FRAP) is a standard method used to study the dynamics of lipids and proteins in artificial and cellular membrane systems. The advent of confocal microscopy two decades ago has made quantitative FRAP easily available to most laboratories. Usually, a single bleaching pattern/area is used and the corresponding recovery time is assumed to directly provide a diffusion coefficient, although this is only true in the case of unrestricted Brownian motion. Here, we propose some general guidelines to perform FRAP experiments under a confocal microscope with different bleaching patterns and area, allowing the experimentalist to establish whether the molecules undergo Brownian motion (free diffusion) or whether they have restricted or directed movements. Using in silico simulations of FRAP measurements, we further indicate the data acquisition criteria that have to be verified in order to obtain accurate values for the diffusion coefficient and to be able to distinguish between different diffusive species. Using this approach, we compare the behavior of lipids in three different membrane platforms (supported lipid bilayers, giant liposomes and sponge phases), and we demonstrate that FRAP measurements are consistent with results obtained using other techniques such as Fluorescence Correlation Spectroscopy (FCS) or Single Particle Tracking (SPT). Finally, we apply this method to show that the presence of the synaptic protein Munc18-1 inhibits the interaction between the synaptic vesicle SNARE protein, VAMP2, and its partner from the plasma membrane, Syn1A.

Objective categorization of interferential tear film lipid layer pattern: validation of the technique

NASA Astrophysics Data System (ADS)

García-Resúa, C.; Giráldez, M. J.; Barreira, N.; Penedo, M. G.; Yebra-Pimentel, E.

2011-05-01

Purpose: The lipid layer of the tear film limits evaporation during the inter-blink interval and also affects tear stability. This study was designed to validate a new software application designed to characterize the tear film lipid layer through texture and colour pattern recognition. Methods: Using the Tearscope-plus (slit lamp magnification 200X), the lipid layer was examined in 105 healthy young adults and interference photographs acquired with a Topcon DV-3 digital camera. The photographs were classified by the new software and by 2 further observers (observer 1 and observer 2) with experience in examining the eye surface. Results: Strong correlation was detected between the categories determined by the new application, observer 1 and observer 2 (Cramer's V, from 0.81 to 0.87, p<0.001). Best agreement (96.2%) was noted between the new method and observers 1 and 2 for recognizing meshwork patterns, whereas observers 1 and 2 showed greatest correspondence when classifying colour fringe patterns. Conclusions: The new application can objectively categorize LLPs using the Tearscope-plus.

Serum LDL cholesterol concentration and lipoprotein electrophoresis pattern in patients with small cell lung cancer.

PubMed

Siemianowicz, K; Gminski, J; Stajszczyk, M; Wojakowski, W; Goss, M; Machalski, M; Telega, A; Brulinski, K; Magiera-Molendowska, H

2000-01-01

Epidemiological studies show that people with low level of total cholesterol have a greater risk of death due to cancer, predominantly lung cancer. The aim of our study was to evaluate serum level of LDL cholesterol and lipoprotein electrophoresis pattern in patients with small cell lung cancer and their dependence on clinical stage of the neoplasm. The studied group consisted of 34 patients with newly diagnosed small cell lung cancer and 39 healthy controls. Fasting level of LDL cholesterol was analyzed and lipoprotein electrophoresis was performed. There were no statistically significant differences of evaluated serum lipid parameters between lung cancer patients and controls, and between the clinical stages of small cell lung cancer.

Part I: In-situ fluorometric quantification of microalgal neutral lipids. Part II: Thermal degradation behavior of investment casting polymer patterns

NASA Astrophysics Data System (ADS)

Zhao, Hongfang

Research described in this dissertation covers two topics. Part-I is focused on in-situ determination of neutral lipid content of microalgae using a lipophilic fluorescent dye. The traditional Nile red stain-based method for detecting microalgal intracellular lipids is limited due to varying composition and thickness of rigid cell walls. In this study, the addition of dilute acid and heating of solution, were found to greatly enhance staining efficiency of Nile red for microalgal species evaluated. Oil-in-water (O/W) microemulsion stabilized by a non-ionic surfactant was employed as a pseudo-standard that mimics lipid-bearing microalgal cells suspended in water. The average neutral lipid contents determined were very close to the results obtained by traditional gravimetric method and solid phase extraction. Part II of the dissertation explores thermo-physico-chemical properties of polymeric pattern materials, including expanded polystyrene (EPS) foam, polyurethane foam, and epoxy stereolithography (SLA) patterns, that are used in investment casting. Density, elastic modulus, expansion coefficient, thermal degradation behavior, etc. were experimentally investigated for their effects on metal casting quality. The reduction in toxic hydrogen cyanide (HCN) generated during thermal decomposition of polyurethane pattern was achieved by increasing either oxidant level or residence time in heated zone. Thermal degradation kinetics of the pattern materials were examined with a thermogravimetric analysis and activation energies were determined by Kissinger and Flynn-Wall-Ozawa methods.

Structure and Thermotropic phase Behavior of Fluorinated Phospholipid Bilayers: A combined Attenuated Total Reflection FTIR Spectroscopy and Imaging Ellipsometry Study

PubMed Central

Schuy, Steffen; Faiss, Simon; Yoder, Nicholas C.; Kalsani, Venkateshwarlu; Kumar, Krishna; Janshoff, Andreas; Vogel, Reiner

2008-01-01

Lipid bilayers consisting of lipids with terminally perfluoroalkylated chains have remarkable properties. They exhibit increased stability and phase-separated nanoscale patterns in mixtures with nonfluorinated lipids. In order to understand the bilayer properties that are responsible for this behavior, we have analyzed the structure of solid-supported bilayers composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and of a DPPC analogue with 6 terminal perfluorinated methylene units (F6-DPPC). Polarized attenuated total reflection Fourier-transform infrared spectroscopy indicates that for F6-DPPC, the tilt of the lipid acyl chains to the bilayer normal is increased to 39° as compared to 21° for native DPPC, for both lipids in the gel phase. This substantial increase of the tilt angle is responsible for a decrease of the bilayer thickness from 5.4 nm for DPPC to 4.5 nm for F6-DPPC, as revealed by temperature-controlled imaging ellipsometry on microstructured lipid bilayers and solution atomic force microscopy. During the main phase transition from the gel to the fluid phase, both the relative bilayer thickness change and the relative area change are substantially smaller for F6-DPPC than for DPPC. In light of these structural and thermotropic data, we propose a model in which the higher acyl-chain tilt angle in F6-DPPC is the result of a conformational rearrangement to minimize unfavorable fluorocarbon–hydrocarbon interactions in the center of the bilayer due to chain staggering. PMID:18563929

Interspecific variability in phosphorus-induced lipid remodelling among marine eukaryotic phytoplankton.

PubMed

Cañavate, José Pedro; Armada, Isabel; Hachero-Cruzado, Ismael

2017-01-01

The response of marine microalgal lipids to phosphorus is of central importance in phytoplankton ecology but remains poorly understood. We determined how taxonomically diverse microalgal species remodelled their lipid class profile in response to phosphorus availability and whether these changes coincided with those already known to occur in land plants and in the limited number of phytoplankton species for which data are available. The complete lipid class profile and specific lipid ratios influenced by phosphorus availability were quantified in two green microalgae and seven Chromalveolates exposed to phosphorus repletion, deprivation and replenishment. Lipid class cell quota changes in the two green microalgae resembled the currently described pattern of betaine lipids substituting for phospholipids under phosphorus depletion, whereas only two of the studied Chromalveolates showed this pattern. Sulpholipids counterbalanced phosphatidylglycerol only in Picochlorum atomus. In all other species, both lipids decreased simultaneously under phosphorus deprivation, although sulpholipids declined more slowly. Phosphorus deprivation always induced a decrease in digalactosyl-diacylglycerol. However, the ratio of digalactosyl-diacylglycerol to total phospholipids increased in eight species and remained unchanged in Isochrysis galbana. Marine phytoplankton seems to have evolved a diversified mechanism for remodelling its lipid class profile under the influence of phosphorus, with cryptophytes and particularly haptophytes exhibiting previously unobserved lipid responses to phosphorus. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Metastable Prepores in Tension-Free Lipid Bilayers

NASA Astrophysics Data System (ADS)

Ting, Christina L.; Awasthi, Neha; Müller, Marcus; Hub, Jochen S.

2018-03-01

The formation and closure of aqueous pores in lipid bilayers is a key step in various biophysical processes. Large pores are well described by classical nucleation theory, but the free-energy landscape of small, biologically relevant pores has remained largely unexplored. The existence of small and metastable "prepores" was hypothesized decades ago from electroporation experiments, but resolving metastable prepores from theoretical models remained challenging. Using two complementary methods—atomistic simulations and self-consistent field theory of a minimal lipid model—we determine the parameters for which metastable prepores occur in lipid membranes. Both methods consistently suggest that pore metastability depends on the relative volume ratio between the lipid head group and lipid tails: lipids with a larger head-group volume fraction (or shorter saturated tails) form metastable prepores, whereas lipids with a smaller head-group volume fraction (or longer unsaturated tails) form unstable prepores.

Lipids as a principle for the identification of Archaebacteria

NASA Technical Reports Server (NTRS)

Tornabene, T. G.; Lloyd, R. E.; Holzer, G.; Oro, J.

1980-01-01

The 'Archaebacteria' consist of several distinct subgroups including methanogens, extreme halophiles and specific thermoacidophiles. These bacteria are distinct from other bacteria with respect to their characteristic RNA compositions, the absence of muramic acid in the cell walls and the predominance of nonsaponifable lipids. The lipid composition of the Archaebacteria consists of isoprenoid and hydroisoprenoid hydrocarbons and isopranyl glycerol ether lipids. The pathways for the biosynthesis of the lipid components are those shared by most microorganisms and demonstrate a close relationship; however, an independent line of descent is indicated by the formation of the isopranyl glycerol ether lipids. This discontinuity formulates a point for delineating the early stages of biological evolution and for dividing bacteria into two subgroups.

CD1c presentation of synthetic glycolipid antigens with foreign alkyl branching motifs

PubMed Central

de Jong, Annemieke; Arce, Eva Casas; Cheng, Tan-Yun; van Summeren, Ruben P.; Feringa, Ben L.; Dudkin, Vadim; Crich, David; Matsunaga, Isamu; Minnaard, Adriaan J.; Moody, D. Branch

2009-01-01

Summary Human CD1c is a protein that activates αβ T cells by presenting self antigens, synthetic mannosyl phosphodolichols and mycobacterial mannosyl phosphopolyketides. To determine which molecular structures of antigens mediate a T cell response, we measured activation by structurally divergent M. tuberculosis mannosyl-β1-phosphomycoketides as well as by synthetic analogs produced by two methods that yield either stereorandom or stereospecific methyl branching patterns. T cell responses required both a phosphate and a β-linked mannose unit, and showed preference for C30–34 lipid units with methyl branches in the S-configuration. Thus, in all cases T cell responses were strongest for synthetic compounds that mimicked the natural branched lipids produced by mycobacterial polyketide synthase 12. Incorporation of methylmalonate to form branched lipids is a common bacterial lipid synthesis pathway that is absent in vertebrates, so the preferential recognition of branched lipids may represent a new type of lipid-based pathogen associated molecular pattern (PAMP). PMID:18022562

Inhomogeneity Based Characterization of Distribution Patterns on the Plasma Membrane

PubMed Central

Paparelli, Laura; Corthout, Nikky; Wakefield, Devin L.; Sannerud, Ragna; Jovanovic-Talisman, Tijana; Annaert, Wim; Munck, Sebastian

2016-01-01

Cell surface protein and lipid molecules are organized in various patterns: randomly, along gradients, or clustered when segregated into discrete micro- and nano-domains. Their distribution is tightly coupled to events such as polarization, endocytosis, and intracellular signaling, but challenging to quantify using traditional techniques. Here we present a novel approach to quantify the distribution of plasma membrane proteins and lipids. This approach describes spatial patterns in degrees of inhomogeneity and incorporates an intensity-based correction to analyze images with a wide range of resolutions; we have termed it Quantitative Analysis of the Spatial distributions in Images using Mosaic segmentation and Dual parameter Optimization in Histograms (QuASIMoDOH). We tested its applicability using simulated microscopy images and images acquired by widefield microscopy, total internal reflection microscopy, structured illumination microscopy, and photoactivated localization microscopy. We validated QuASIMoDOH, successfully quantifying the distribution of protein and lipid molecules detected with several labeling techniques, in different cell model systems. We also used this method to characterize the reorganization of cell surface lipids in response to disrupted endosomal trafficking and to detect dynamic changes in the global and local organization of epidermal growth factor receptors across the cell surface. Our findings demonstrate that QuASIMoDOH can be used to assess protein and lipid patterns, quantifying distribution changes and spatial reorganization at the cell surface. An ImageJ/Fiji plugin of this analysis tool is provided. PMID:27603951

Metastable Prepores in Tension-Free Lipid Bilayers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ting, Christina L.; Awasthi, Neha; Muller, Marcus

The formation and closure of aqueous pores in lipid bilayers is a key step in various biophysical processes. Large pores are well described by classical nucleation theory, but the free-energy landscape of small, biologically relevant pores has remained largely unexplored. The existence of small and metastable “prepores” was hypothesized decades ago from electroporation experiments, but resolving metastable prepores from theoretical models remained challenging. Using two complementary methods—atomistic simulations and self-consistent field theory of a minimal lipid model—we determine the parameters for which metastable prepores occur in lipid membranes. Here, both methods consistently suggest that pore metastability depends on the relativemore » volume ratio between the lipid head group and lipid tails: lipids with a larger head-group volume fraction (or shorter saturated tails) form metastable prepores, whereas lipids with a smaller head-group volume fraction (or longer unsaturated tails) form unstable prepores.« less

Metastable Prepores in Tension-Free Lipid Bilayers

DOE PAGES

Ting, Christina L.; Awasthi, Neha; Muller, Marcus; ...

2018-03-23

The formation and closure of aqueous pores in lipid bilayers is a key step in various biophysical processes. Large pores are well described by classical nucleation theory, but the free-energy landscape of small, biologically relevant pores has remained largely unexplored. The existence of small and metastable “prepores” was hypothesized decades ago from electroporation experiments, but resolving metastable prepores from theoretical models remained challenging. Using two complementary methods—atomistic simulations and self-consistent field theory of a minimal lipid model—we determine the parameters for which metastable prepores occur in lipid membranes. Here, both methods consistently suggest that pore metastability depends on the relativemore » volume ratio between the lipid head group and lipid tails: lipids with a larger head-group volume fraction (or shorter saturated tails) form metastable prepores, whereas lipids with a smaller head-group volume fraction (or longer unsaturated tails) form unstable prepores.« less

Patterning of supported lipid bilayers and proteins using material selective nitrodopamine-mPEG.

PubMed

Spycher, Philipp R; Hall, Heike; Vogel, Viola; Reimhult, Erik

2015-01-01

We present a generic patterning process by which biomolecules in a passivated background are patterned directly from physiological buffer to microfabricated surfaces without the need for further processing. First, nitrodopamine-mPEG is self-assembled to selectively render TiO2 patterns non-fouling to biomolecule adsorption on hydrophilic and adhesive glass surfaces. After the controlled TiO2 passivation, the biomolecules can be directly adsorbed from solution in a single step creating large scale micropatterned and highly homogeneous arrays of biomolecules with very high pattern definition. We demonstrate the formation of fluid supported lipid bilayers (SLBs) down to the single μm-level limited only by the photolithographic process. Non-specific adsorption of lipid vesicles to the TiO2 background was found to be almost completely suppressed. The SLB patterns can be further selectively functionalized with retained mobility, which we demonstrate through biotin-streptavidin coupling. We envision this single step patterning approach to be very beneficial for membrane-based biosensors and for pattering of cells on a passivated background with complex, sub-cellular geometries; in each application the adherent areas have a tunable mobility of interaction sites controlled by the fluidity of the membrane.

Analysis of cutin and suberin biomarker patterns in alluvial sedi-ments

NASA Astrophysics Data System (ADS)

Herschbach, Jennifer; Sesterheim, Anna; König, Frauke; Fuchs, Elmar

2015-04-01

Cutin and suberin are the primary source of hydrolysable aliphatic lipid polyesters in soil organic matter (SOM). They are known as geochemical biomarkers to estimate the contribution of different plant species and tissues to SOM. Despite their potential as biomarkers, cutin and suberin have received less attention as flood plain sediment biomarkers. The objectives of this study were to investigate the efficiency of cutin and suberin as biomarkers in floodplains. Therefore similarities between the lipid pattern in alluvial sediments and in the actual vegetation were considered. Lipids of plant tissues (roots, twigs, leaves) from different species (reed (e.g. Phalaris arun-diacea), Salix alba, Ulmus laevis and grassland (e.g. Carex spec.)) and of the un-derlying soils and sediments were obtained and investigated at four sites in the nature reserve Knoblauchsaue (Hessen, Germany). The four sampling sites differ not only with respect to their vegetation, but also within their distance to the river Rhine. Cutin and suberin monomers of plants and soils were analysed by alkaline hydrolysis, methylation and acetylation and subsequent gas chromatography-mass spectrometry. Resulting lipid patterns were specific for the appropriate plant species and tissues. However, the traceability of single selected lipids was decreasing alongside the soil profile, with the exception of monomers in softwood floodplain soils. Selected tissue specific lipid ratios showed a higher traceability due to strong attributions of lipid ratios in soils and roots of U. laevis and Carex spec. and in leaves of U. laevis and S. alba. In contrast, there was no accordance between the suberin specific lipid ratios in soils and roots of S. alba and P. arundiacea. The most robust interpretations were afforded when a set of multiple biomarkers (i.e. a combination of free lipid ratios and ratios of hydrolysable lipids) was used to collectively reconstruct the source vegetation of different sediment layers.

Greater adherence to a Mediterranean dietary pattern is associated with improved plasma lipid profile: the Aragon Health Workers Study cohort.

PubMed

Peñalvo, José L; Oliva, Belén; Sotos-Prieto, Mercedes; Uzhova, Irina; Moreno-Franco, Belén; León-Latre, Montserrat; Ordovás, José María

2015-04-01

There is wide recognition of the importance of healthy eating in cardiovascular health promotion. The purpose of this study was to identify the main dietary patterns among a Spanish population, and to determine their relationship with plasma lipid profiles. A cross-sectional analysis was conducted of data from 1290 participants of the Aragon Workers Health Study cohort. Standardized protocols were used to collect clinical and biochemistry data. Diet was assessed through a food frequency questionnaire, quantifying habitual intake over the past 12 months. The main dietary patterns were identified by factor analysis. The association between adherence to dietary patterns and plasma lipid levels was assessed by linear and logistic regression. Two dietary patterns were identified: a Mediterranean dietary pattern, high in vegetables, fruits, fish, white meat, nuts, and olive oil, and a Western dietary pattern, high in red meat, fast food, dairy, and cereals. Compared with the participants in the lowest quintile of adherence to the Western dietary pattern, those in the highest quintile had 4.6 mg/dL lower high-density lipoprotein cholesterol levels (P < .001), 8 mg/dL lower apolipoprotein A1 levels (P = .005) and a greater risk of having decreased high-density lipoprotein cholesterol (odds ratio = 3.19; 95% confidence interval, 1.36-7.5; P-trend = .03). Participants adhering to the Mediterranean dietary pattern had 3.3mg/dL higher high-density lipoprotein cholesterol levels (P < .001), and a ratio of triglycerides to high-density lipoprotein cholesterol that was 0.43 times lower (P = .043). Adherence to the Mediterranean dietary pattern is associated with improved lipid profile compared with a Western dietary pattern, which was associated with a lower odds of optimal high-density lipoprotein cholesterol levels in this population. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Toward the establishment of standardized in vitro tests for lipid-based formulations, part 1: method parameterization and comparison of in vitro digestion profiles across a range of representative formulations.

PubMed

Williams, Hywel D; Sassene, Philip; Kleberg, Karen; Bakala-N'Goma, Jean-Claude; Calderone, Marilyn; Jannin, Vincent; Igonin, Annabel; Partheil, Anette; Marchaud, Delphine; Jule, Eduardo; Vertommen, Jan; Maio, Mario; Blundell, Ross; Benameur, Hassan; Carrière, Frédéric; Müllertz, Anette; Porter, Christopher J H; Pouton, Colin W

2012-09-01

The Lipid Formulation Classification System Consortium is an industry-academia collaboration, established to develop standardized in vitro methods for the assessment of lipid-based formulations (LBFs). In this first publication, baseline conditions for the conduct of digestion tests are suggested and a series of eight model LBFs are described to probe test performance across different formulation types. Digestion experiments were performed in vitro using a pH-stat apparatus and danazol employed as a model poorly water-soluble drug. LBF digestion (rate and extent) and drug solubilization patterns on digestion were examined. To evaluate cross-site reproducibility, experiments were conducted at two sites and highly consistent results were obtained. In a further refinement, bench-top centrifugation was explored as a higher throughput approach to separation of the products of digestion (and compared with ultracentrifugation), and conditions under which this method was acceptable were defined. Drug solubilization was highly dependent on LBF composition, but poorly correlated with simple performance indicators such as dispersion efficiency, confirming the utility of the digestion model as a means of formulation differentiation. Copyright © 2012 Wiley Periodicals, Inc.

Lipid metabolism-related gene expression pattern of Atlantic bluefin tuna (Thunnus thynnus L.) larvae fed on live prey.

PubMed

Betancor, Mónica B; Ortega, Aurelio; de la Gándara, Fernando; Tocher, Douglas R; Mourente, Gabriel

2017-04-01

The present study is the first to evaluate lipid metabolism in first-feeding Atlantic bluefin tuna (ABT; Thunnus thynnus L.) larvae fed different live prey including enriched rotifers Brachionus plicatilis and Acartia sp. copepod nauplii from 2 days after hatch. Understanding the molecular basis of lipid metabolism and regulation in ABT will provide insights to optimize diet formulations for this high-value species new to aquaculture. To this end, we investigated the effect of dietary lipid on whole larvae lipid class and fatty acid compositions and the expression of key genes involved in lipid metabolism in first feeding ABT larvae fed different live prey. Additionally, the expression of lipid metabolism genes in tissues of adult broodstock ABT was evaluated. Growth and survival data indicated that copepods were the best live prey for first feeding ABT and that differences in growth performance and lipid metabolism observed between larvae from different year classes could be a consequence of broodstock nutrition. In addition, expression patterns of lipid metabolic genes observed in ABT larvae in the trials could reflect differences in lipid class and fatty acid compositions of the live prey. The lipid nutritional requirements, including essential fatty acid requirements of larval ABT during the early feeding stages, are unknown, and the present study represents a first step in addressing these highly relevant issues. However, further studies are required to determine nutritional requirements and understand lipid metabolism during development of ABT larvae and to apply the knowledge to the commercial culture of this iconic species.

Differential affinities of MinD and MinE to anionic phospholipid influence Min Patterning dynamics in vitro

PubMed Central

Vecchiarelli, Anthony G.; Li, Min; Mizuuchi, Michiyo; Mizuuchi, Kiyoshi

2014-01-01

The E. coli Min system forms a cell-pole-to-cell-pole oscillator that positions the divisome at mid-cell. The MinD ATPase binds the membrane and recruits the cell division inhibitor MinC. MinE interacts with and releases MinD (and MinC) from the membrane. The chase of MinD by MinE creates the in vivo oscillator that maintains a low level of the division inhibitor at mid-cell. In vitro reconstitution and visualization of Min proteins on a supported lipid bilayer has provided significant advances in understanding Min patterns in vivo. Here we studied the effects of flow, lipid composition, and salt concentration on Min patterning. Flow and no-flow conditions both supported Min protein patterns with somewhat different characteristics. Without flow, MinD and MinE formed spiraling waves. MinD and, to a greater extent MinE, have stronger affinities for anionic phospholipid. MinD-independent binding of MinE to anionic lipid resulted in slower and narrower waves. MinE binding to the bilayer was also more susceptible to changes in ionic strength than MinD. We find that modulating protein diffusion with flow, or membrane binding affinities with changes in lipid composition or salt concentration, can differentially affect the retention time of MinD and MinE, leading to spatiotemporal changes in Min patterning. PMID:24930948

Simple Analysis of Lipid Inhibition Activity on an Adipocyte Micro-Cell Pattern Chip.

PubMed

Kim, Gi Yong; Yeom, Su-Jin; Jang, Sung-Chan; Lee, Chang-Soo; Roh, Changhyun; Jeong, Heon-Ho

2018-06-04

Polydimethyl-siloxane (PDMS) is often applied to fabricate cell chips. In this study, we fabricated an adipocyte microcell pattern chips using PDMS to analyze the inhibition activity of lipid droplets in mouse embryo fibroblast cells (3T3-L1) with anti-obesity agents. To form the PDMS based micropattern, we applied the micro-contact printing technique using PDMS micro-stamps that had been fabricated by conventional soft lithography. This PDMS micro-pattern enabled the selective growth of 3T3-L1 cells onto the specific region by preventing cell adhesion on the PDMS region. It then allowed growth of the 3T3-L1 cells in the chip for 10 days and confirmed that lipid droplets were formed in the 3T3-L1 cells. After treatment of orlistat and quercetin were treated in an adipocyte micro-cell pattern chip with 3T3-L1 cells for six days, we found that orlistat and quercetin exhibited fat inhibition capacities of 19.3% and 24.4% from 0.2 μM of lipid droplets in 3T3-L1 cells. In addition, we conducted a direct quantitative analysis of 3T3-L1 cell differentiation using Oil Red O staining. In conclusion, PDMS-based adipocyte micro-cell pattern chips may contribute to the development of novel bioactive compounds.

Bisphenol A Exposure May Induce Hepatic Lipid Accumulation via Reprogramming the DNA Methylation Patterns of Genes Involved in Lipid Metabolism

NASA Astrophysics Data System (ADS)

Ke, Zhang-Hong; Pan, Jie-Xue; Jin, Lu-Yang; Xu, Hai-Yan; Yu, Tian-Tian; Ullah, Kamran; Rahman, Tanzil Ur; Ren, Jun; Cheng, Yi; Dong, Xin-Yan; Sheng, Jian-Zhong; Huang, He-Feng

2016-08-01

Accumulating evidence suggests a role of bisphenol A (BPA) in metabolic disorders. However, the underlying mechanism is still unclear. Using a mouse BPA exposure model, we investigated the effects of long-term BPA exposure on lipid metabolism and the underlying mechanisms. The male mice exposed to BPA (0.5 μg BPA /kg/day, a human relevant dose) for 10 months exhibited significant hepatic accumulation of triglycerides and cholesterol. The liver cells from the BPA-exposed mice showed significantly increased expression levels of the genes related to lipid synthesis. These liver cells showed decreased DNA methylation levels of Srebf1 and Srebf2, and increased expression levels of Srebf1 and Srebf2 that may upregulate the genes related to lipid synthesis. The expression levels of DNA methyltransferases were decreased in BPA-exposed mouse liver. Hepa1-6 cell line treated with BPA showed decreased expression levels of DNA methyltransferases and increased expression levels of genes involved in lipid synthesis. DNA methyltransferase knockdown in Hepa1-6 led to hypo-methylation and increased expression levels of genes involved in lipid synthesis. Our results suggest that long-term BPA exposure could induce hepatic lipid accumulation, which may be due to the epigenetic reprogramming of the genes involved in lipid metabolism, such as the alterations of DNA methylation patterns.

Bisphenol A Exposure May Induce Hepatic Lipid Accumulation via Reprogramming the DNA Methylation Patterns of Genes Involved in Lipid Metabolism

PubMed Central

Ke, Zhang-Hong; Pan, Jie-Xue; Jin, Lu-Yang; Xu, Hai-Yan; Yu, Tian-Tian; Ullah, Kamran; Rahman, Tanzil Ur; Ren, Jun; Cheng, Yi; Dong, Xin-Yan; Sheng, Jian-Zhong; Huang, He-Feng

2016-01-01

Accumulating evidence suggests a role of bisphenol A (BPA) in metabolic disorders. However, the underlying mechanism is still unclear. Using a mouse BPA exposure model, we investigated the effects of long-term BPA exposure on lipid metabolism and the underlying mechanisms. The male mice exposed to BPA (0.5 μg BPA /kg/day, a human relevant dose) for 10 months exhibited significant hepatic accumulation of triglycerides and cholesterol. The liver cells from the BPA-exposed mice showed significantly increased expression levels of the genes related to lipid synthesis. These liver cells showed decreased DNA methylation levels of Srebf1 and Srebf2, and increased expression levels of Srebf1 and Srebf2 that may upregulate the genes related to lipid synthesis. The expression levels of DNA methyltransferases were decreased in BPA-exposed mouse liver. Hepa1-6 cell line treated with BPA showed decreased expression levels of DNA methyltransferases and increased expression levels of genes involved in lipid synthesis. DNA methyltransferase knockdown in Hepa1-6 led to hypo-methylation and increased expression levels of genes involved in lipid synthesis. Our results suggest that long-term BPA exposure could induce hepatic lipid accumulation, which may be due to the epigenetic reprogramming of the genes involved in lipid metabolism, such as the alterations of DNA methylation patterns. PMID:27502578

Comparative atomic-scale hydration of the ceramide and phosphocholine headgroup in solution and bilayer environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gillams, Richard J.; McLain, Sylvia E., E-mail: sylvia.mclain@bioch.ox.ac.uk; Lorenz, Christian D., E-mail: chris.lorenz@kcl.ac.uk

2016-06-14

Previous studies have used neutron diffraction to elucidate the hydration of the ceramide and the phosphatidylcholine headgroup in solution. These solution studies provide bond-length resolution information on the system, but are limited to liquid samples. The work presented here investigates how the hydration of ceramide and phosphatidylcholine headgroups in a solution compares with that found in a lipid bilayer. This work shows that the hydration patterns seen in the solution samples provide valuable insight into the preferential location of hydrating water molecules in the bilayer. There are certain subtle differences in the distribution, which result from a combination of themore » lipid conformation and the lipid-lipid interactions within the bilayer environment. The lipid-lipid interactions in the bilayer will be dependent on the composition of the bilayer, whereas the restricted exploration of conformational space is likely to be applicable in all membrane environments. The generalized description of hydration gathered from the neutron diffraction studies thus provides good initial estimation for the hydration pattern, but this can be further refined for specific systems.« less

Exploiting lipopolysaccharide-induced deformation of lipid bilayers to modify membrane composition and generate two-dimensional geometric membrane array patterns

DOE PAGES

Adams, Peter G.; Swingle, Kirstie L.; Paxton, Walter F.; ...

2015-05-27

Supported lipid bilayers have proven effective as model membranes for investigating biophysical processes and in development of sensor and array technologies. The ability to modify lipid bilayers after their formation and in situ could greatly advance membrane technologies, but is difficult via current state-of-the-art technologies. Here we demonstrate a novel method that allows the controlled post-formation processing and modification of complex supported lipid bilayer arrangements, under aqueous conditions. We exploit the destabilization effect of lipopolysaccharide, an amphiphilic biomolecule, interacting with lipid bilayers to generate voids that can be backfilled to introduce desired membrane components. We further demonstrate that when usedmore » in combination with a single, traditional soft lithography process, it is possible to generate hierarchically-organized membrane domains and microscale 2-D array patterns of domains. Significantly, this technique can be used to repeatedly modify membranes allowing iterative control over membrane composition. This approach expands our toolkit for functional membrane design, with potential applications for enhanced materials templating, biosensing and investigating lipid-membrane processes.« less

Distribution of health-related social surplus in pharmaceuticals: an estimation of consumer and producer surplus in the management of high blood lipids and COPD.

PubMed

Refoios Camejo, Rodrigo; Camejo, Rodrigo Refoios; McGrath, Clare; Miraldo, Marisa; Rutten, Frans

2014-05-01

Following suggestions that developers should be allowed to capture a defined share of the total value generated by their technologies, the amount of surplus accruing to the pharmaceutical industry has become an important concept when discussing policies to encourage innovation in healthcare. Observational clinical and market data spanning over a period of 20 years were applied in order to estimate the social surplus generated by pharmaceuticals used in the management of high cholesterol and chronic obstructive pulmonary disease (COPD). The distribution of social surplus between consumers and producers was also computed and the dynamics of rent extraction examined. Health-related social surplus increased consistently over time for both disease areas, mostly due to the launch of more effective technologies and a greater number of patients being treated for the conditions. However, the growth rate of social surplus differed for each disease and dissimilar patterns of distribution between consumer and producer surplus emerged across the years. For lipid-lowering therapies, yearly consumer surplus reaches 85 % of total health-related social surplus after the loss of exclusivity of major molecules, whilst for COPD it ranges from 54 to 69 %. Average producer surplus is approximately 25 % of total health-related social surplus in the lipid-lowering market between 1990 and 2010, and 37 % for COPD between 2001 and 2010. The share of surplus captured by non-innovative generic producers also varies differently across periods for both markets, reaching 11.12 % in the case of lipid-lowering therapies but just 1.55 % in the case of COPD. A considerable amount of the value may be recouped by consumers only towards the end of the lifecycle. Elements affecting the distribution of social surplus vary across disease areas and include the market pricing structure and the pattern of clinical effectiveness observed over time. The application of a longer-term disease specific perspective may be required when assessing the cost-effectiveness of health technologies at launch.

Stable carbon isotopic compositions of intact polar lipids reveal complex carbon flow patterns among hydrocarbon degrading microbial communities at the Chapopote asphalt volcano

NASA Astrophysics Data System (ADS)

Schubotz, Florence; Lipp, Julius S.; Elvert, Marcus; Hinrichs, Kai-Uwe

2011-08-01

Seepage of asphalt forms the basis of a cold seep system at 3000 m water depth at the Chapopote Knoll in the southern Gulf of Mexico. Anaerobic microbial communities are stimulated in the oil-impregnated sediments as evidenced by the presence of intact polar membrane lipids (IPLs) derived from archaea and Bacteria at depths up to 7 m below the seafloor. Detailed investigation of stable carbon isotope composition (δ 13C) of alkyl and acyl moieties derived from a range of IPL precursors with distinct polar head groups resolved the complexity of carbon metabolisms and utilization of diverse carbon sources by uncultured microbial communities. In surface sediments most of the polar lipid-derived fatty acids with phosphatidylethanolamine (PE), phosphatidylglycerol (PG) and diphosphatidylglycerol (DPG) head groups could be tentatively assigned to autotrophic sulfate-reducing bacteria, with a relatively small proportion involved in the anaerobic oxidation of methane. Derivatives of phosphatidyl-( N)-methylethanolamine (PME) were abundant and could be predominantly assigned to heterotrophic oil-degrading bacteria. Archaeal IPLs with phosphate-based hydroxyarchaeols and diglycosidic glyceroldibiphytanylglyceroltetraethers (GDGTs) were assigned to methanotrophic archaea of the ANME-2 and ANME-1 cluster, respectively, whereas δ 13C values of phosphate-based archaeols and mixed phosphate-based and diglycosidic GDGTs point to methanogenic archaea. At a 7 m deep sulfate-methane transition zone that is linked to the upward movement of gas-laden petroleum, a distinct increase in abundance of archaeal IPLs such as phosphate-based hydroxyarchaeols and diglycosidic archaeol and GDGTs is observed; their δ 13C values are consistent with their origin from both methanotrophic and methanogenic archaea. This study reveals previously hidden, highly complex patterns in the carbon-flow of versatile microbial communities involved in the degradation of heavy oil including hydrocarbon gases that would not have been evident from classical compound-specific isotope analyses of either bulk IPL or apolar lipid derivatives.

Coconut oil consumption and cardiovascular risk factors in humans

PubMed Central

Eyres, Michael F.; Chisholm, Alexandra; Brown, Rachel C.

2016-01-01

Coconut oil is being heavily promoted as a healthy oil, with benefits that include support of heart health. To assess the merits of this claim, the literature on the effect of coconut consumption on cardiovascular risk factors and outcomes in humans was reviewed. Twenty-one research papers were identified for inclusion in the review: 8 clinical trials and 13 observational studies. The majority examined the effect of coconut oil or coconut products on serum lipid profiles. Coconut oil generally raised total and low-density lipoprotein cholesterol to a greater extent than cis unsaturated plant oils, but to a lesser extent than butter. The effect of coconut consumption on the ratio of total cholesterol to high-density lipoprotein cholesterol was often not examined. Observational evidence suggests that consumption of coconut flesh or squeezed coconut in the context of traditional dietary patterns does not lead to adverse cardiovascular outcomes. However, due to large differences in dietary and lifestyle patterns, these findings cannot be applied to a typical Western diet. Overall, the weight of the evidence from intervention studies to date suggests that replacing coconut oil with cis unsaturated fats would alter blood lipid profiles in a manner consistent with a reduction in risk factors for cardiovascular disease. PMID:26946252

Electrodiffusion of lipids on membrane surfaces.

PubMed

Zhou, Y C

2012-05-28

Lateral translocation of lipids and proteins is a universal process on membrane surfaces. Local aggregation or organization of lipids and proteins can be induced when the random lateral motion is mediated by the electrostatic interactions and membrane curvature. Although the lateral diffusion rates of lipids on membranes of various compositions are measured and the electrostatic free energies of predetermined protein-membrane-lipid systems can be computed, the process of the aggregation and the evolution to the electrostatically favorable states remain largely undetermined. Here we propose an electrodiffusion model, based on the variational principle of the free energy functional, for the self-consistent lateral drift-diffusion of multiple species of charged lipids on membrane surfaces. Finite sizes of lipids are modeled to enforce the geometrical constraint of the lipid concentration on membrane surfaces. A surface finite element method is developed to appropriate the Laplace-Beltrami operators in the partial differential equations of the model. Our model properly describes the saturation of lipids on membrane surfaces, and correctly predicts that the MARCKS peptide can consistently sequester three multivalent phosphatidylinositol 4,5-bisphosphate lipids through its basic amino acid residues, regardless of a wide range of the percentage of monovalent phosphatidylserine in the membrane.

Electrodiffusion of lipids on membrane surfaces

NASA Astrophysics Data System (ADS)

Zhou, Y. C.

2012-05-01

Lateral translocation of lipids and proteins is a universal process on membrane surfaces. Local aggregation or organization of lipids and proteins can be induced when the random lateral motion is mediated by the electrostatic interactions and membrane curvature. Although the lateral diffusion rates of lipids on membranes of various compositions are measured and the electrostatic free energies of predetermined protein-membrane-lipid systems can be computed, the process of the aggregation and the evolution to the electrostatically favorable states remain largely undetermined. Here we propose an electrodiffusion model, based on the variational principle of the free energy functional, for the self-consistent lateral drift-diffusion of multiple species of charged lipids on membrane surfaces. Finite sizes of lipids are modeled to enforce the geometrical constraint of the lipid concentration on membrane surfaces. A surface finite element method is developed to appropriate the Laplace-Beltrami operators in the partial differential equations of the model. Our model properly describes the saturation of lipids on membrane surfaces, and correctly predicts that the MARCKS peptide can consistently sequester three multivalent phosphatidylinositol 4,5-bisphosphate lipids through its basic amino acid residues, regardless of a wide range of the percentage of monovalent phosphatidylserine in the membrane.

Exercise effects on lipids in persons with varying dietary patterns - Does diet matter if they exercise? Responses in STRRIDE I

PubMed Central

Huffman, Kim M.; Hawk, Victoria H.; Henes, Sarah T.; Ocampo, Christine I.; Orenduff, Melissa C.; Slentz, Cris A.; Johnson, Johanna L.; Houmard, Joseph A.; Samsa, Gregory P.; Kraus, William E.; Bales, Connie W.

2012-01-01

Background The standard clinical approach for reducing cardiovascular disease risk due to dyslipidemia is to prescribe changes in diet and physical activity. The purpose of the current study was to determine if, across a range of dietary patterns, there were variable lipoprotein responses to an aerobic exercise training intervention. Methods Subjects were participants in the Studies of a Targeted Risk Reduction Intervention through Defined Exercise (STRRIDE I), a supervised exercise program in sedentary, overweight subjects randomized to 6 months of inactivity or one of 3 aerobic exercise programs. To characterize diet patterns observed during the study, we calculated a modified z-score that included intakes of total fat, saturated fat, trans fatty acids, cholesterol, omega-3 fatty acids and fiber as compared to the 2006 AHA diet recommendations. Linear models were used to evaluate relationships between diet patterns and exercise effects on lipoproteins/lipids. Results Independent of diet, exercise had beneficial effects on LDL-cholesterol particle number, LDL-cholesterol size, HDL-cholesterol, HDL-cholesterol size, and triglycerides (P<0.05 for all). However, having a diet pattern that closely adhered to AHA recommendations was not related to changes in these or any other serum lipids or lipoproteins in any of the exercise groups. Conclusions We found that even in sedentary individuals whose habitual diets vary in the extent of adherence to AHA dietary recommendations, a rigorous, supervised exercise intervention can achieve significant beneficial lipid effects. PMID:22795291

Speciation of lipids and humus-like colloidal compounds in a forest soil reclaimed with municipal solid waste compost.

PubMed

Zancada, M Cristina; Almendros, Gonzalo; Sanz, Jesús; Román, Román

2004-02-01

The progressive transformations of lipid and humus-like fractions in soil after massive input (400 Mg ha(-1)) of urban waste have been studied during an 87-week experiment in field plots of a degraded Calcic Regosol in Central Spain. Structural changes in the macromolecular fractions were small when compared with the qualitative and quantitative changes in lipid composition. The intense depletion of the lipid fraction with time and the decrease of the humic acid to fulvic acid ratio were the most significant quantitative indices of the compost transformation in soil. Changes in soil lipid fractions were especially noted in relation to their speciation status and distribution patterns (carbon preference index and relative chain length). Three subfractions were considered: (I) direct extraction with petroleum ether, (II) liquid-liquid extraction after soil treatment with 2 M H3PO4 and (III) after soil treatment with 0.1 M NaOH. Although lipid concentration tends to decrease with time, lipids in the fraction tightly bonded to soil (III) remained qualitatively and quantitatively constant in the course of the field experiment. Gas chromatographic-mass spectrometric analyses showed that the more stable the association of lipid to the soil matrix, the fewer the changes observed in the distribution pattern of the fatty acids during the progressive transformation stages.

Accumulation of cholesterol and increased demand for zinc in serum-deprived RPE cells

PubMed Central

Mishra, Sanghamitra; Peterson, Katherine; Yin, Lili; Berger, Alan; Fan, Jianguo

2016-01-01

Purpose Having observed that confluent ARPE-19 cells (derived from human RPE) survive well in high-glucose serum-free medium (SFM) without further feeding for several days, we investigated the expression profile of RPE cells under the same conditions. Methods Expression profiles were examined with microarray and quantitative PCR (qPCR) analyses, followed by western blot analysis of key regulated proteins. The effects of low-density lipoprotein (LDL) and zinc supplementation were examined with qPCR. Immunofluorescence was used to localize the LDL receptor and to examine LDL uptake. Cellular cholesterol levels were measured with filipin binding. Expression patterns in primary fetal RPE cells were compared using qPCR. Results Microarray analyses of gene expression in ARPE-19, confirmed with qPCR, showed upregulation of lipid and cholesterol biosynthesis pathways in SFM. At the protein level, the cholesterol synthesis control factor SRBEF2 was activated, and other key lipid synthesis proteins increased. Supplementation of SFM with LDL reversed the upregulation of lipid and cholesterol synthesis genes, but not of cholesterol transport genes. The LDL receptor relocated to the plasma membrane, and LDL uptake was activated by day 5–7 in SFM, suggesting increased demand for cholesterol. Confluent ARPE-19 cells in SFM accumulated intracellular cholesterol, compared with cells supplemented with serum, over 7 days. Over the same time course in SFM, the expression of metallothioneins decreased while the major zinc transporter was upregulated, consistent with a parallel increase in demand for zinc. Supplementation with zinc reversed expression changes for metallothionein genes, but not for other zinc-related genes. Similar patterns of regulation were also seen in primary fetal human RPE cells in SFM. Conclusions ARPE-19 cells respond to serum deprivation and starvation with upregulation of the lipid and cholesterol pathways, accumulation of intracellular cholesterol, and increased demand for zinc. Similar trends are seen in primary fetal RPE cells. Cholesterol accumulation basal to RPE is a prominent feature of age-related macular degeneration (AMD), while dietary zinc is protective. It is conceivable that accumulating defects in Bruch’s membrane and dysfunction of the choriocapillaris could impede transport between RPE and vasculature in AMD. Thus, this pattern of response to serum deprivation in RPE-derived cells may have relevance for some aspects of the progression of AMD. PMID:28003730

Lipids as universal biomarkers of extraterrestrial life.

PubMed

Georgiou, Christos D; Deamer, David W

2014-06-01

In 1965, James Lovelock published a general statement, based on thermodynamic chemical equilibrium principles, about how to detect extant or extinct life on a planet other than Earth. Nearly 50 years later, it is possible to make such measurements with robotic missions such as current and future Mars rovers, and probes to sample icy plumes of Enceladus or Europa. We make a specific recommendation that certain characteristic patterns in the composition of lipid hydrocarbons can only result from a biological process, because the signal arises from a universal requirement related to lipid bilayer fluidity and membrane stability. Furthermore, the pattern can be preserved over millions of years, and instrumentation is already available to be incorporated into flight missions.

Evolution and development of model membranes for physicochemical and functional studies of the membrane lateral heterogeneity.

PubMed

Morigaki, Kenichi; Tanimoto, Yasushi

2018-03-14

One of the main questions in the membrane biology is the functional roles of membrane heterogeneity and molecular localization. Although segregation and local enrichment of protein/lipid components (rafts) have been extensively studied, the presence and functions of such membrane domains still remain elusive. Along with biochemical, cell observation, and simulation studies, model membranes are emerging as an important tool for understanding the biological membrane, providing quantitative information on the physicochemical properties of membrane proteins and lipids. Segregation of fluid lipid bilayer into liquid-ordered (Lo) and liquid-disordered (Ld) phases has been studied as a simplified model of raft in model membranes, including giant unilamellar vesicles (GUVs), giant plasma membrane vesicles (GPMVs), and supported lipid bilayers (SLB). Partition coefficients of membrane proteins between Lo and Ld phases were measured to gauze their affinities to lipid rafts (raftophilicity). One important development in model membrane is patterned SLB based on the microfabrication technology. Patterned Lo/Ld phases have been applied to study the partition and function of membrane-bound molecules. Quantitative information of individual molecular species attained by model membranes is critical for elucidating the molecular functions in the complex web of molecular interactions. The present review gives a short account of the model membranes developed for studying the lateral heterogeneity, especially focusing on patterned model membranes on solid substrates. Copyright © 2018 Elsevier B.V. All rights reserved.

Identification of lptA, lpxE, and lpxO, Three Genes Involved in the Remodeling of Brucella Cell Envelope.

PubMed

Conde-Álvarez, Raquel; Palacios-Chaves, Leyre; Gil-Ramírez, Yolanda; Salvador-Bescós, Miriam; Bárcena-Varela, Marina; Aragón-Aranda, Beatriz; Martínez-Gómez, Estrella; Zúñiga-Ripa, Amaia; de Miguel, María J; Bartholomew, Toby Leigh; Hanniffy, Sean; Grilló, María-Jesús; Vences-Guzmán, Miguel Ángel; Bengoechea, José A; Arce-Gorvel, Vilma; Gorvel, Jean-Pierre; Moriyón, Ignacio; Iriarte, Maite

2017-01-01

The brucellae are facultative intracellular bacteria that cause a worldwide extended zoonosis. One of the pathogenicity mechanisms of these bacteria is their ability to avoid rapid recognition by innate immunity because of a reduction of the pathogen-associated molecular pattern (PAMP) of the lipopolysaccharide (LPS), free-lipids, and other envelope molecules. We investigated the Brucella homologs of lptA, lpxE , and lpxO , three genes that in some pathogens encode enzymes that mask the LPS PAMP by upsetting the core-lipid A charge/hydrophobic balance. Brucella lptA , which encodes a putative ethanolamine transferase, carries a frame-shift in B. abortus but not in other Brucella spp. and phylogenetic neighbors like the opportunistic pathogen Ochrobactrum anthropi. Consistent with the genomic evidence, a B. melitensis lptA mutant lacked lipid A-linked ethanolamine and displayed increased sensitivity to polymyxin B (a surrogate of innate immunity bactericidal peptides), while B. abortus carrying B. melitensis lptA displayed increased resistance. Brucella lpxE encodes a putative phosphatase acting on lipid A or on a free-lipid that is highly conserved in all brucellae and O. anthropi. Although we found no evidence of lipid A dephosphorylation, a B. abortus lpxE mutant showed increased polymyxin B sensitivity, suggesting the existence of a hitherto unidentified free-lipid involved in bactericidal peptide resistance. Gene lpxO putatively encoding an acyl hydroxylase carries a frame-shift in all brucellae except B. microti and is intact in O. anthropi . Free-lipid analysis revealed that lpxO corresponded to olsC , the gene coding for the ornithine lipid (OL) acyl hydroxylase active in O. anthropi and B. microti , while B. abortus carrying the olsC of O. anthropi and B. microti synthesized hydroxylated OLs. Interestingly, mutants in lptA, lpxE , or olsC were not attenuated in dendritic cells or mice. This lack of an obvious effect on virulence together with the presence of the intact homolog genes in O. anthropi and B. microti but not in other brucellae suggests that LptA, LpxE, or OL β-hydroxylase do not significantly alter the PAMP properties of Brucella LPS and free-lipids and are therefore not positively selected during the adaptation to intracellular life.

Association and interaction between dietary pattern and VEGF receptor-2 (VEGFR2) gene polymorphisms on blood lipids in Chinese Malaysian and Japanese adults.

PubMed

Yap, Roseline Wai Kuan; Shidoji, Yoshihiro; Hon, Wei Min; Masaki, Motofumi

2012-01-01

Dietary pattern and genetic predisposition of each population have different impacts on lifestyle-related chronic diseases. This study was conducted to evaluate the association and interaction between dietary patterns and VEGFR2 or KDR gene polymorphisms on physical and biochemical risk factors of cardiovascular disease in two Asian populations (179 Chinese Malaysian and 136 Japanese adults). Dietary patterns were constructed from food frequency questionnaire using factor analysis. Genotyping of rs1870377 and rs2071559 was performed by real-time PCR using TaqMan probes. Physical measurements: body mass index, systolic and diastolic blood pressures and biochemical parameters: glycated hemoglobin A1c and blood lipids (total cholesterol, triglycerides, LDL-cholesterol, HDL-cholesterol and total cholesterol/HDL-C ratio) were measured. Two dietary patterns were extracted for: Japanese ('Japanese diet' and 'Western diet') and Chinese Malaysians ('Balanced diet'; and 'Meat, rice and noodles diet'). In Japanese, 'Western Diet' and rs2071559 were associated with LDL-C and HDL-C, respectively. In Chinese Malaysians, 'Meat, rice and noodles diet' was asso-ciated with triglycerides, HDL-C and total cholesterol/HDL ratio while rs1870377 and rs2071559 were associated with total cholesterol and/or LDL-C. The interaction between 'Western Diet' and rs2071559 in Japanese and 'Meat, rice and noodles diet' and rs1870377 in Malaysians had significant effects on blood lipids after adjusting for confounders. The association and interaction of dietary patterns and VEGFR2 gene polymorphisms on blood lipids differ between Chinese Malaysian and Japanese subjects by either decreasing or increasing the risk of cardiovascular disease.

Ultrastructural study on dynamics of lipid bodies and plastids during ripening of chili pepper fruits.

PubMed

Liu, Lin

2013-03-01

Dynamics of lipid bodies and plastids in chili pepper fruits during ripening were investigated by means of transmission electron microscopy. Mesocarp of chili pepper fruits consists of collenchyma, normal parenchyma, and huge celled parenchyma. In mature green fruits, plastids contain numerous thylakoids that are well organized into grana in collenchyma, a strikingly huge amount of starch and irregularly organized thylakoids in normal parenchyma, and simple tubes rather than thylakoids in huge celled parenchyma. These morphological features suggest that plastids are chloroplasts in collenchyma, chloroamyloplasts in normal parenchyma, proplastids in huge celled parenchyma. As fruits ripen to red, plastids in all cell types convert to chromoplasts and, concomitantly, lipid bodies accumulate in both cytoplasm and chromoplasts. Cytosolic lipid bodies are lined up in a regular layer adjacent to plasma membrane. The cytosolic lipid body consists of a core surrounded by a membrane. The core is comprised of a more electron-dense central part enclosed by a slightly less electron-dense peripheral layer. Plastidial lipid bodies in collenchyma, normal parenchyma, and endodermis initiate as plastoglobuli, which in turn convert to rod-like structures. Therefore, plastidial lipid bodies are more dynamic than cytosolic lipid bodies. Both cytosolic and plastidial lipid bodies contain rich unsaturated lipids. Copyright © 2012 Elsevier Ltd. All rights reserved.

Use of Solid Phase Extraction in the Biochemistry Laboratory to Separate Different Lipids

ERIC Educational Resources Information Center

Flurkey, William H.

2005-01-01

Solid-phase extraction (SPE) was used to demonstrate how various lipids and lipid classes could be separated in a biochemistry laboratory setting. Three different SPE methods were chosen on their ability to separate a lipid mixture, consisting of a combination of a either a fatty acid, a triacylglycerol, a mono- or diacylglycerol, phospholipid,…

A Comparative Study of Human Saposins.

PubMed

Garrido-Arandia, María; Cuevas-Zuviría, Bruno; Díaz-Perales, Araceli; Pacios, Luis F

2018-02-14

Saposins are small proteins implicated in trafficking and loading of lipids onto Cluster of Differentiation 1 (CD1) receptor proteins that in turn present lipid antigens to T cells and a variety of T-cell receptors, thus playing a crucial role in innate and adaptive immune responses in humans. Despite their low sequence identity, the four types of human saposins share a similar folding pattern consisting of four helices linked by three conserved disulfide bridges. However, their lipid-binding abilities as well as their activities in extracting, transporting and loading onto CD1 molecules a variety of sphingo- and phospholipids in biological membranes display two striking characteristics: a strong pH-dependence and a structural change between a compact, closed conformation and an open conformation. In this work, we present a comparative computational study of structural, electrostatic, and dynamic features of human saposins based upon their available experimental structures. By means of structural alignments, surface analyses, calculation of pH-dependent protonation states, Poisson-Boltzmann electrostatic potentials, and molecular dynamics simulations at three pH values representative of biological media where saposins fulfill their function, our results shed light into their intrinsic features. The similarities and differences in this class of proteins depend on tiny variations of local structural details that allow saposins to be key players in triggering responses in the human immune system.

Establishing multiple omics baselines for three Southeast Asian populations in the Singapore Integrative Omics Study.

PubMed

Saw, Woei-Yuh; Tantoso, Erwin; Begum, Husna; Zhou, Lihan; Zou, Ruiyang; He, Cheng; Chan, Sze Ling; Tan, Linda Wei-Lin; Wong, Lai-Ping; Xu, Wenting; Moong, Don Kyin Nwe; Lim, Yenly; Li, Bowen; Pillai, Nisha Esakimuthu; Peterson, Trevor A; Bielawny, Tomasz; Meikle, Peter J; Mundra, Piyushkumar A; Lim, Wei-Yen; Luo, Ma; Chia, Kee-Seng; Ong, Rick Twee-Hee; Brunham, Liam R; Khor, Chiea-Chuen; Too, Heng Phon; Soong, Richie; Wenk, Markus R; Little, Peter; Teo, Yik-Ying

2017-09-21

The Singapore Integrative Omics Study provides valuable insights on establishing population reference measurement in 364 Chinese, Malay, and Indian individuals. These measurements include > 2.5 millions genetic variants, 21,649 transcripts expression, 282 lipid species quantification, and 284 clinical, lifestyle, and dietary variables. This concept paper introduces the depth of the data resource, and investigates the extent of ethnic variation at these omics and non-omics biomarkers. It is evident that there are specific biomarkers in each of these platforms to differentiate between the ethnicities, and intra-population analyses suggest that Chinese and Indians are the most biologically homogeneous and heterogeneous, respectively, of the three groups. Consistent patterns of correlations between lipid species also suggest the possibility of lipid tagging to simplify future lipidomics assays. The Singapore Integrative Omics Study is expected to allow the characterization of intra-omic and inter-omic correlations within and across all three ethnic groups through a systems biology approach.The Singapore Genome Variation projects characterized the genetics of Singapore's Chinese, Malay, and Indian populations. The Singapore Integrative Omics Study introduced here goes further in providing multi-omic measurements in individuals from these populations, including genetic, transcriptome, lipidome, and lifestyle data, and will facilitate the study of common diseases in Asian communities.

Maternal diets deficient in folic acid and related methyl donors modify mechanisms associated with lipid metabolism in the fetal liver of the rat.

PubMed

McNeil, Christopher J; Hay, Susan M; Rucklidge, Garry J; Reid, Martin D; Duncan, Gary J; Rees, William D

2009-11-01

Previously we have examined the effects of diets deficient in folic acid ( - F) or folate deficient with low methionine and choline ( - F LM LC) on the relative abundance of soluble proteins in the liver of the pregnant rat. In the present study we report the corresponding changes in the fetal liver at day 21 of gestation. The abundance of eighteen proteins increased when dams were fed the - F diet. When dams were fed the - F LM LC diet, thirty-three proteins increased and eight decreased. Many of the differentially abundant proteins in the fetal liver could be classified into the same functional groups as those previously identified in the maternal liver, namely protein synthesis, metabolism, lipid metabolism and proteins associated with the cytoskeleton and endoplasmic reticulum. The pattern was consistent with reduced cell proliferation in the - F LM LC group but not in the - F group. Metabolic enzymes associated with lipid metabolism changed in both the - F and - F LM LC groups. The mRNA for carnitine palmitoyl transferase were up-regulated and CD36 (fatty acid translocase) down-regulated in the - F group, suggesting increased mitochondrial oxidation of fatty acids as an indirect response to altered maternal lipid metabolism. In the - F LM LC group the mRNA for acetyl CoA carboxylase was down-regulated, suggesting reduced fatty acid synthesis. The mRNA for transcriptional regulators including PPARalpha and sterol response element-binding protein-1c were unchanged. These results suggest that an adequate supply of folic acid and the related methyl donors may benefit fetal development directly by improving lipid metabolism in fetal as well as maternal tissues.

Entropic Anomaly Observed in Lipid Polymorphisms Induced by Surfactant Peptide SP-B(1-25).

PubMed

Tran, Nhi; Kurian, Justin; Bhatt, Avni; McKenna, Robert; Long, Joanna R

2017-10-05

The N-terminal 25 amino-acid residues of pulmonary surfactant protein B (SP-B 1-25 ) induces unusual lipid polymorphisms in a model lipid system, 4:1 DPPC/POPG, mirroring the lipid composition of native pulmonary surfactant. It is widely suggested that SP-B 1-25 -induced lipid polymorphisms within the alveolar aqueous subphase provide a structural platform for rapid lipid adsorption to the air-water interface. Here, we characterize in detail the phase behavior of DPPC and POPG in hydrated lipid assemblies containing therapeutic levels of SP-B 1-25 using 2 H and 31 P solid state NMR spectroscopy. The appearance of a previously observed isotropic lipid phase is found to be highly dependent on the thermal cycling of the samples. Slow heating of frozen samples leads to phase separation of DPPC into a lamellar phase whereas POPG lipids interact with the peptide to form an isotropic phase at physiologic temperature. Rapid heating of frozen samples to room temperature leads to strongly isotropic phase behavior for both DPPC and POPG lipids, with DPPC in exchange between isotropic and interdigitated phases. 31 P T 2 relaxation times confirm the isotropic phase to be consistent with a lipid cubic phase. The observed phases exhibit thermal stability up to physiologic temperature (37 °C) and are consistent with the formation of a ripple phase containing a large number of peptide-induced membrane structural defects enabling rapid transit of lipids between lipid lamellae. The coexistance of a lipid cubic phase with interdigitated lipids suggests a specific role for the highly conserved N-terminus of SP-B in stabilizing this unusual lipid polymorphism.

Minimal 2'-O-methyl phosphorothioate linkage modification pattern of synthetic guide RNAs for increased stability and efficient CRISPR-Cas9 gene editing avoiding cellular toxicity

PubMed Central

Basila, Megan; Kelley, Melissa L.

2017-01-01

Since its initial application in mammalian cells, CRISPR-Cas9 has rapidly become a preferred method for genome engineering experiments. The Cas9 nuclease is targeted to genomic DNA using guide RNAs (gRNA), either as the native dual RNA system consisting of a DNA-targeting CRISPR RNA (crRNA) and a trans-activating crRNA (tracrRNA), or as a chimeric single guide RNA (sgRNA). Entirely DNA-free CRISPR-Cas9 systems using either Cas9 protein or Cas9 mRNA and chemically synthesized gRNAs allow for transient expression of CRISPR-Cas9 components, thereby reducing the potential for off-targeting, which is a significant advantage in therapeutic applications. In addition, the use of synthetic gRNA allows for the incorporation of chemical modifications for enhanced properties including improved stability. Previous studies have demonstrated the utility of chemically modified gRNAs, but have focused on one pattern with multiple modifications in co-electroporation with Cas9 mRNA or multiple modifications and patterns with Cas9 plasmid lipid co-transfections. Here we present gene editing results using a series of chemically modified synthetic sgRNA molecules and chemically modified crRNA:tracrRNA molecules in both electroporation and lipid transfection assessing indel formation and/or phenotypic gene knockout. We show that while modifications are required for co-electroporation with Cas9 mRNA, some modification patterns of the gRNA are toxic to cells compared to the unmodified gRNA and most modification patterns do not significantly improve gene editing efficiency. We also present modification patterns of the gRNA that can modestly improve Cas9 gene editing efficiency when co-transfected with Cas9 mRNA or Cas9 protein (> 1.5-fold difference). These results indicate that for certain applications, including those relevant to primary cells, the incorporation of some, but not all chemical modification patterns on synthetic crRNA:tracrRNA or sgRNA can be beneficial to CRISPR-Cas9 gene editing. PMID:29176845

Minimal 2'-O-methyl phosphorothioate linkage modification pattern of synthetic guide RNAs for increased stability and efficient CRISPR-Cas9 gene editing avoiding cellular toxicity.

PubMed

Basila, Megan; Kelley, Melissa L; Smith, Anja van Brabant

2017-01-01

Since its initial application in mammalian cells, CRISPR-Cas9 has rapidly become a preferred method for genome engineering experiments. The Cas9 nuclease is targeted to genomic DNA using guide RNAs (gRNA), either as the native dual RNA system consisting of a DNA-targeting CRISPR RNA (crRNA) and a trans-activating crRNA (tracrRNA), or as a chimeric single guide RNA (sgRNA). Entirely DNA-free CRISPR-Cas9 systems using either Cas9 protein or Cas9 mRNA and chemically synthesized gRNAs allow for transient expression of CRISPR-Cas9 components, thereby reducing the potential for off-targeting, which is a significant advantage in therapeutic applications. In addition, the use of synthetic gRNA allows for the incorporation of chemical modifications for enhanced properties including improved stability. Previous studies have demonstrated the utility of chemically modified gRNAs, but have focused on one pattern with multiple modifications in co-electroporation with Cas9 mRNA or multiple modifications and patterns with Cas9 plasmid lipid co-transfections. Here we present gene editing results using a series of chemically modified synthetic sgRNA molecules and chemically modified crRNA:tracrRNA molecules in both electroporation and lipid transfection assessing indel formation and/or phenotypic gene knockout. We show that while modifications are required for co-electroporation with Cas9 mRNA, some modification patterns of the gRNA are toxic to cells compared to the unmodified gRNA and most modification patterns do not significantly improve gene editing efficiency. We also present modification patterns of the gRNA that can modestly improve Cas9 gene editing efficiency when co-transfected with Cas9 mRNA or Cas9 protein (> 1.5-fold difference). These results indicate that for certain applications, including those relevant to primary cells, the incorporation of some, but not all chemical modification patterns on synthetic crRNA:tracrRNA or sgRNA can be beneficial to CRISPR-Cas9 gene editing.

Exercise effects on lipids in persons with varying dietary patterns-does diet matter if they exercise? Responses in Studies of a Targeted Risk Reduction Intervention through Defined Exercise I.

PubMed

Huffman, Kim M; Hawk, Victoria H; Henes, Sarah T; Ocampo, Christine I; Orenduff, Melissa C; Slentz, Cris A; Johnson, Johanna L; Houmard, Joseph A; Samsa, Gregory P; Kraus, William E; Bales, Connie W

2012-07-01

The standard clinical approach for reducing cardiovascular disease risk due to dyslipidemia is to prescribe changes in diet and physical activity. The purpose of the current study was to determine if, across a range of dietary patterns, there were variable lipoprotein responses to an aerobic exercise training intervention. Subjects were participants in the STRRIDE I, a supervised exercise program in sedentary, overweight subjects randomized to 6 months of inactivity or 1 of 3 aerobic exercise programs. To characterize diet patterns observed during the study, we calculated a modified z-score that included intakes of total fat, saturated fat, trans fatty acids, cholesterol, omega-3 fatty acids, and fiber as compared with the 2006 American Heart Association diet recommendations. Linear models were used to evaluate relationships between diet patterns and exercise effects on lipoproteins/lipids. Independent of diet, exercise had beneficial effects on low-density lipoprotein cholesterol particle number, low-density lipoprotein cholesterol size, high-density lipoprotein cholesterol, high-density lipoprotein cholesterol size, and triglycerides (P < .05 for all). However, having a diet pattern that closely adhered to American Heart Association recommendations was not related to changes in these or any other serum lipids or lipoproteins in any of the exercise groups. We found that even in sedentary individuals whose habitual diets vary in the extent of adherence to AHA dietary recommendations, a rigorous, supervised exercise intervention can achieve significant beneficial lipid effects. Copyright © 2012 Mosby, Inc. All rights reserved.

Controlling carbon-nanotube-phospholipid solubility by curvature-dependent self-assembly.

PubMed

Määttä, Jukka; Vierros, Sampsa; Sammalkorpi, Maria

2015-03-12

Control of aqueous dispersion is central in the processing and usage of nanoscale hydrophobic objects. However, selecting dispersive agents based on the size and form of the hydrophobic object and the role of coating morphology in dispersion efficiency remain important open questions. Here, the effect of the substrate and the dispersing molecule curvature, as well as, the influence of dispersant concentration on the adsorption morphology are examined by molecular simulations of graphene and carbon nanotube (CNT) substrates with phospholipids of varying curvature as the dispersing agents. Lipid spontaneous curvature is increased from close to zero (effectively cylindrical lipid) to highly positive (effectively conical lipid) by studying double tailed dipalmitoylphosphadidylcholine (DPPC) and single tailed lysophosphadidylcholine (LPC) which differ in the number of acyl chains but have identical headgroup. We find that lipids are good dispersion agents for both planar and curved nanoparticles and induce a dispersive barrier nonsize selectively. Differences in dispersion efficiency arise from lipid headgroup density and their extension from the hydrophobic substrate in the adsorption morphology. We map the packing morphology contributing factors and report that the aggregate morphologies depend on the competition of interactions rising from (1) hydrophobicity driven maximization of lipid-substrate contacts and lipid self-adhesion, (2) tail bending energy cost, (3) preferential alignment along the graphitic substrate principal axes, and (4) lipid headgroup preferential packing. Curved substrates adjust the morphology by changing the balance between the interaction strengths. Jointly, the findings show substrate curvature and dimensions are a way to tune lipid adsorption to desired, self-assembling patterns. Besides engineering dispersion efficiency, the findings could bear significance in designing materials with defined molecular scale, molecular coatings for orientation specific CNT assembly or lipid-based molecular masks and patterning on graphene.

Molecular structure of the lecithin ripple phase

NASA Astrophysics Data System (ADS)

de Vries, Alex H.; Yefimov, Serge; Mark, Alan E.; Marrink, Siewert J.

2005-04-01

Molecular dynamics simulations of lecithin lipid bilayers in water as they are cooled from the liquid crystalline phase show the spontaneous formation of rippled bilayers. The ripple consists of two domains of different length and orientation, connected by a kink. The organization of the lipids in one domain of the ripple is found to be that of a splayed gel; in the other domain the lipids are gel-like and fully interdigitated. In the concave part of the kink region between the domains the lipids are disordered. The results are consistent with the experimental information available and provide an atomic-level model that may be tested by further experiments. molecular dynamics simulation | structural model

Crowding-Induced Mixing Behavior of Lipid Bilayers: Examination of Mixing Energy, Phase, Packing Geometry, and Reversibility.

PubMed

Zeno, Wade F; Rystov, Alice; Sasaki, Darryl Y; Risbud, Subhash H; Longo, Marjorie L

2016-05-10

In an effort to develop a general thermodynamic model from first-principles to describe the mixing behavior of lipid membranes, we examined lipid mixing induced by targeted binding of small (Green Fluorescent Protein (GFP)) and large (nanolipoprotein particles (NLPs)) structures to specific phases of phase-separated lipid bilayers. Phases were targeted by incorporation of phase-partitioning iminodiacetic acid (IDA)-functionalized lipids into ternary lipid mixtures consisting of DPPC, DOPC, and cholesterol. GFP and NLPs, containing histidine tags, bound the IDA portion of these lipids via a metal, Cu(2+), chelating mechanism. In giant unilamellar vesicles (GUVs), GFP and NLPs bound to the Lo domains of bilayers containing DPIDA, and bound to the Ld region of bilayers containing DOIDA. At sufficiently large concentrations of DPIDA or DOIDA, lipid mixing was induced by bound GFP and NLPs. The validity of the thermodynamic model was confirmed when it was found that the statistical mixing distribution as a function of crowding energy for smaller GFP and larger NLPs collapsed to the same trend line for each GUV composition. Moreover, results of this analysis show that the free energy of mixing for a ternary lipid bilayer consisting of DOPC, DPPC, and cholesterol varied from 7.9 × 10(-22) to 1.5 × 10(-20) J/lipid at the compositions observed, decreasing as the relative cholesterol concentration was increased. It was discovered that there appears to be a maximum packing density, and associated maximum crowding pressure, of the NLPs, suggestive of circular packing. A similarity in mixing induced by NLP1 and NLP3 despite large difference in projected areas was analytically consistent with monovalent (one histidine tag) versus divalent (two histidine tags) surface interactions, respectively. In addition to GUVs, binding and induced mixing behavior of NLPs was also observed on planar, supported lipid multibilayers. The mixing process was reversible, with Lo domains reappearing after addition of EDTA for NLP removal.

Crowding-induced mixing behavior of lipid bilayers: Examination of mixing energy, phase, packing geometry, and reversibility

DOE PAGES

Zeno, Wade F.; Rystov, Alice; Sasaki, Darryl Y.; ...

2016-04-20

In an effort to develop a general thermodynamic model from first-principles to describe the mixing behavior of lipid membranes, we examined lipid mixing induced by targeted binding of small (Green Fluorescent Protein (GFP)) and large (nanolipoprotein particles (NLPs)) structures to specific phases of phase-separated lipid bilayers. Phases were targeted by incorporation of phase-partitioning iminodiacetic acid (IDA)-functionalized lipids into ternary lipid mixtures consisting of DPPC, DOPC, and cholesterol. GFP and NLPs, containing histidine tags, bound the IDA portion of these lipids via a metal, Cu 2+, chelating mechanism. In giant unilamellar vesicles (GUVs), GFP and NLPs bound to the Lo domainsmore » of bilayers containing DPIDA, and bound to the Ld region of bilayers containing DOIDA. At sufficiently large concentrations of DPIDA or DOIDA, lipid mixing was induced by bound GFP and NLPs. The validity of the thermodynamic model was confirmed when it was found that the statistical mixing distribution as a function of crowding energy for smaller GFP and larger NLPs collapsed to the same trend line for each GUV composition. Moreover, results of this analysis show that the free energy of mixing for a ternary lipid bilayer consisting of DOPC, DPPC, and cholesterol varied from 7.9 × 10 –22 to 1.5 × 10 –20 J/lipid at the compositions observed, decreasing as the relative cholesterol concentration was increased. It was discovered that there appears to be a maximum packing density, and associated maximum crowding pressure, of the NLPs, suggestive of circular packing. A similarity in mixing induced by NLP1 and NLP3 despite large difference in projected areas was analytically consistent with monovalent (one histidine tag) versus divalent (two histidine tags) surface interactions, respectively. In addition to GUVs, binding and induced mixing behavior of NLPs was also observed on planar, supported lipid multibilayers. Furthermore, the mixing process was reversible, with Lo domains reappearing after addition of EDTA for NLP removal.« less

Crowding-induced mixing behavior of lipid bilayers: Examination of mixing energy, phase, packing geometry, and reversibility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeno, Wade F.; Rystov, Alice; Sasaki, Darryl Y.

In an effort to develop a general thermodynamic model from first-principles to describe the mixing behavior of lipid membranes, we examined lipid mixing induced by targeted binding of small (Green Fluorescent Protein (GFP)) and large (nanolipoprotein particles (NLPs)) structures to specific phases of phase-separated lipid bilayers. Phases were targeted by incorporation of phase-partitioning iminodiacetic acid (IDA)-functionalized lipids into ternary lipid mixtures consisting of DPPC, DOPC, and cholesterol. GFP and NLPs, containing histidine tags, bound the IDA portion of these lipids via a metal, Cu 2+, chelating mechanism. In giant unilamellar vesicles (GUVs), GFP and NLPs bound to the Lo domainsmore » of bilayers containing DPIDA, and bound to the Ld region of bilayers containing DOIDA. At sufficiently large concentrations of DPIDA or DOIDA, lipid mixing was induced by bound GFP and NLPs. The validity of the thermodynamic model was confirmed when it was found that the statistical mixing distribution as a function of crowding energy for smaller GFP and larger NLPs collapsed to the same trend line for each GUV composition. Moreover, results of this analysis show that the free energy of mixing for a ternary lipid bilayer consisting of DOPC, DPPC, and cholesterol varied from 7.9 × 10 –22 to 1.5 × 10 –20 J/lipid at the compositions observed, decreasing as the relative cholesterol concentration was increased. It was discovered that there appears to be a maximum packing density, and associated maximum crowding pressure, of the NLPs, suggestive of circular packing. A similarity in mixing induced by NLP1 and NLP3 despite large difference in projected areas was analytically consistent with monovalent (one histidine tag) versus divalent (two histidine tags) surface interactions, respectively. In addition to GUVs, binding and induced mixing behavior of NLPs was also observed on planar, supported lipid multibilayers. Furthermore, the mixing process was reversible, with Lo domains reappearing after addition of EDTA for NLP removal.« less

Dyslipidemia patterns are differentially associated with dietary factors.

PubMed

Song, SuJin; Paik, Hee Young; Park, Minseon; Song, YoonJu

2016-08-01

Dyslipidemia, a strong predictor of cardiovascular diseases, is prevalent among Korean adults, but little is known about the associations between overall lipid profiles and dietary factors. We identified dyslipidemia patterns among lipid indicators and examined dietary factors associated with dyslipidemia patterns in Korean adults. Subjects in this cross-sectional study were recruited from the Family Medicine Division or the Health Examination Center of the general hospital in Seoul between 2010 and 2012. Measurements of biochemical and dietary variables repeated three times were collected from a total of 138 subjects at 3- to 4-month intervals when the subjects visited the hospital. Dietary intake data were obtained using 24-h recalls. In order to estimate typical values for biochemical and dietary variables, the averages of repeated measures for each subject were calculated. To identify dyslipidemia patterns, factor analysis was used based on total cholesterol (TC), low-density lipoprotein cholesterol (LDLC), triglycerides (TG), and high-density lipoprotein cholesterol (HDLC). Two dyslipidemia patterns, (1) TC & LDLC and (2) TG & HDLC, were identified. Dietary fat and cholesterol intakes were positively associated with the TC & LDLC pattern score, but not associated with the TG & HDLC pattern score. The TG & HDLC pattern was significantly associated with low intakes of calcium, potassium, milk and dairy products. Two dyslipidemia patterns were associated with dietary factors in Korean adults. Further studies should investigate specific dietary recommendations according to lipid profiles in the prevention and management of dyslipidemia in Korea. Copyright © 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Sodium lauryl sulphate alters the mRNA expression of lipid-metabolizing enzymes and PPAR signalling in normal human skin in vivo.

PubMed

Törmä, Hans; Berne, Berit

2009-12-01

Detergents irritate skin and affect skin barrier homeostasis. In this study, healthy skin was exposed to 1% sodium lauryl sulphate (SLS) in water for 24 h. Biopsies were taken 6 h to 8 days post exposure. Lipid patterns were stained in situ and real-time polymerase chain reaction (PCR) was used to examine mRNA expression of enzymes synthesizing barrier lipids, peroxisome proliferator-activated receptors (PPAR) and lipoxygenases. The lipid pattern was disorganized from 6 h to 3 days after SLS exposure. Concomitant changes in mRNA expression included: (i) reduction, followed by induction, of ceramide-generating beta-glucocerebrosidase, (ii) increase on day 1 of two other enzymes for ceramide biosynthesis and (iii) persistent reduction of acetyl-CoA carboxylase-B, a key enzyme in fatty acid synthesis. Surprisingly, the rate-limiting enzyme in cholesterol synthesis, HMG-CoA reductase, was unaltered. Among putative regulators of barrier lipids synthesis, PPARalpha and PPARgamma exhibited reduced mRNA expression, while PPARbeta/delta and LXRbeta were unaltered. Epidermal lipoxygenase-3, which may generate PPARalpha agonists, exhibited reduced expression. In conclusion, SLS induces reorganization of lipids in the stratum corneum, which play a role in detergents' destruction of the barrier. The changes in mRNA expression of enzymes involved in synthesizing barrier lipids are probably important for the restoration of the barrier.

Two short questionnaires on leisure-time physical activity compared with serum lipids, anthropometric measurements and aerobic power in a suburban population from Oslo, Norway.

PubMed

Graff-Iversen, Sidsel; Anderssen, Sigmund Alfred; Holme, Ingar Morten; Jenum, Anne Karen; Raastad, Truls

2008-01-01

The aim was to indirectly validate two short postal questionnaires measuring leisure-time physical activity (LPA) by comparing the answers with serum lipids and anthropometric measurements. All inhabitants aged 31-67 years in two suburban, multicultural areas of Oslo, Norway were invited to "Romsås in Motion", a community intervention survey, in 2000. Of those, 2950 participants (48%) met and were re-invited in 2003. LPA was measured by two short instruments used since the 1970s (referred to as the Gothenburg instrument) and since 1994 in Cohort of Norway (CONOR). Each instrument was compared with relevant measurements at baseline including LPA according to an adapted version of the long International Physical Activity Questionnaire (IPAQ-L). In addition, changes during 2000--2003 in reported LPA were compared with changes in body weight, waist-to-hip ratio, lipids and other measurements. LPA measured by the Gothenburg instrument correlated weakly, but consistently with relevant biological and anthropometrical measurements and with IPAQ-L. The correlation coefficients were -0.1-(-0.2) with triglycerides, total-to-high density lipoprotein (HDL)-cholesterol ratio and waist-to-hip ratio, around 0.1 with HDL-cholesterol and 0.3 with maximal aerobic power. For the CONOR instrument a similar pattern was found in both sexes for the hard LPA and in women for light LPA. LPA measured by each short instrument was in line with LPA measured with IPAQ-L. In a multi-linguistic, suburban population in Oslo, Norway, LPA measurements by each of two short questionnaires were weakly, but consistently correlated with relevant biological and anthropometric measurements and strongly with IPAQ-L.

Effects of prefermented cereal-derived substrates (ground barley and rye bran) enriched with fungal γ-linolenic acid on rumen fermentation parameters and lipid metabolism in vitro.

PubMed

Laho, T; Váradyová, Z; Mihaliková, K; Kišidayová, S; Adamechová, Z; Certík, M; Jalč, D

2011-09-01

To increase rumen output of γ-linolenic acid (GLA), we used two cereal-derived substrates, ground barley (GB) and rye bran (RB), enriched with fungal GLA as components of feed rations. We examined their effects on rumen fermentation patterns, lipid metabolism and the ciliated protozoan population in an artificial rumen. Four diets consisting of meadow hay (MH) plus unfermented (GB or RB) or prefermented (GB - TE or RB - TE) cereal-derived substrates were fermented in an artificial rumen with ovine rumen inoculum. The cereal-derived substrates were prefermented with the fungus Thamnidium elegans (TE) by fungal solid-state fermentation. The diets with TE increased the rumen input of dietary GLA (mg day(-1)) from 0 to 21 (GB - TE) or 26 (RB - TE). Both experimental diets increased the rumen output of GLA (P < 0.001). Adverse effects on the ciliate population were observed. Both diets also had an effect on the fatty acids profile. Fermentation patterns were also affected with MH + RB - TE. Cereal-derived substrates enriched with GLA effectively enhanced the output of GLA in artificial rumen. The ability of the fungal strain T. elegans to grow and utilize various agro-industrial substrates might be useful in developing potential new animal diets enriched in GLA. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

Coconut oil consumption and cardiovascular risk factors in humans.

PubMed

Eyres, Laurence; Eyres, Michael F; Chisholm, Alexandra; Brown, Rachel C

2016-04-01

Coconut oil is being heavily promoted as a healthy oil, with benefits that include support of heart health. To assess the merits of this claim, the literature on the effect of coconut consumption on cardiovascular risk factors and outcomes in humans was reviewed. Twenty-one research papers were identified for inclusion in the review: 8 clinical trials and 13 observational studies. The majority examined the effect of coconut oil or coconut products on serum lipid profiles. Coconut oil generally raised total and low-density lipoprotein cholesterol to a greater extent than cis unsaturated plant oils, but to a lesser extent than butter. The effect of coconut consumption on the ratio of total cholesterol to high-density lipoprotein cholesterol was often not examined. Observational evidence suggests that consumption of coconut flesh or squeezed coconut in the context of traditional dietary patterns does not lead to adverse cardiovascular outcomes. However, due to large differences in dietary and lifestyle patterns, these findings cannot be applied to a typical Western diet. Overall, the weight of the evidence from intervention studies to date suggests that replacing coconut oil with cis unsaturated fats would alter blood lipid profiles in a manner consistent with a reduction in risk factors for cardiovascular disease. © The Author(s) 2016. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Reconstitution of the Hepatic Asialoglycoprotein Receptor with Phospholipid Vesicles

NASA Astrophysics Data System (ADS)

Klausner, Richard D.; Bridges, Kenneth; Tsunoo, Hajime; Blumenthal, Robert; Weinstein, John N.; Ashwell, Gilbert

1980-09-01

A solubilized detergent-free preparation of the hepatic binding protein specific for asialoglycoproteins associates spontaneously with small unilamellar lipid vesicles. This process is independent of the phase transition of the lipid and effectively restores the specific binding activity of the receptor protein. The insensitivity of the resulting lipid-protein complex to ionic strength provides evidence for a hydrophobic interaction. There is a perturbation of the lipid phase transition concomitant with addition of the protein. Circular dichroism studies indicate that the protein undergoes a conformational change on association with lipid. Binding of specific ligand produces further physical changes in the receptor as indicated by alterations in the tryptophan fluorescence quenching pattern.

Changeover from signalling to energy-provisioning lipids during transition from colostrum to mature milk in the giant panda (Ailuropoda melanoleuca)

PubMed Central

Zhang, Tong; Watson, David G.; Zhang, Rong; Hou, Rong; Loeffler, I. Kati; Kennedy, Malcolm W.

2016-01-01

Among the large placental mammals, ursids give birth to the most altricial neonates with the lowest neonatal:maternal body mass ratios. This is particularly exemplified by giant pandas. To examine whether there is compensation for the provision of developmentally important nutrients that other species groups may provide in utero, we examined changes in the lipids of colostrum and milk with time after birth in giant pandas. Lipids that are developmental signals or signal precursors, and those that are fundamental to nervous system construction, such as docosahexaenoic acid (DHA) and phosphatidylserines, appear early and then fall dramatically in concentration to a baseline at 20–30 days. The dynamics of lysophosphatidic acid and eicosanoids display similar patterns, but with progressive differences between mothers. Triglycerides occur at relatively low levels initially and increase in concentration until a plateau is reached at about 30 days. These patterns indicate an early provision of signalling lipids and their precursors, particularly lipids crucial to brain, retinal and central nervous system development, followed by a changeover to lipids for energy metabolism. Thus, in giant pandas, and possibly in all bears, lactation is adapted to provisioning a highly altricial neonate to a degree that suggests equivalence to an extension of gestation. PMID:27808224

Changeover from signalling to energy-provisioning lipids during transition from colostrum to mature milk in the giant panda (Ailuropoda melanoleuca).

PubMed

Zhang, Tong; Watson, David G; Zhang, Rong; Hou, Rong; Loeffler, I Kati; Kennedy, Malcolm W

2016-11-03

Among the large placental mammals, ursids give birth to the most altricial neonates with the lowest neonatal:maternal body mass ratios. This is particularly exemplified by giant pandas. To examine whether there is compensation for the provision of developmentally important nutrients that other species groups may provide in utero, we examined changes in the lipids of colostrum and milk with time after birth in giant pandas. Lipids that are developmental signals or signal precursors, and those that are fundamental to nervous system construction, such as docosahexaenoic acid (DHA) and phosphatidylserines, appear early and then fall dramatically in concentration to a baseline at 20-30 days. The dynamics of lysophosphatidic acid and eicosanoids display similar patterns, but with progressive differences between mothers. Triglycerides occur at relatively low levels initially and increase in concentration until a plateau is reached at about 30 days. These patterns indicate an early provision of signalling lipids and their precursors, particularly lipids crucial to brain, retinal and central nervous system development, followed by a changeover to lipids for energy metabolism. Thus, in giant pandas, and possibly in all bears, lactation is adapted to provisioning a highly altricial neonate to a degree that suggests equivalence to an extension of gestation.

Lipid-rich and protein-poor carbon allocation patterns of phytoplankton in the northern Chukchi Sea, 2011

NASA Astrophysics Data System (ADS)

Yun, Mi Sun; Joo, Hui Tae; Park, Jung Woo; Kang, Jae Joong; Kang, Sung-Ho; Lee, Sang H.

2018-04-01

The carbon allocations of phytoplankton into different photosynthetic end products (lipids, LMWM, polysaccharides, and proteins) were determined to understand physiological conditions of phytoplankton in the northern Chukchi Sea during the Korean Arctic expedition, 2011, using the 13C isotope tracer technique. The carbon allocation rates of lipids, LMWM, polysaccharides, and proteins were 0.00009-0.00062 h-1, 0.00001-0.00049 h-1, 0.00001-0.00025 h-1, and 0.00001-0.00062 h-1 within the euphotic depths from surface to 1% light depths during our cruise period, respectively. Significant relationships between protein production rates and chlorophyll a concentrations (large and total) were found in this study. Moreover, we found a significant negative relationship between lipid production rates and ammonium concentrations. These relationships match well with the previous results for environmental/physiological conditions for phytoplankton growth. Overall, phytoplankton allocated more photosynthetic carbon into lipids (42.5 ± 17.7%) whereas relatively lower to proteins (20.4 ± 15.5%) in this study. The lipid-rich and protein-poor allocation patterns in this study suggest that phytoplankton in the northern Chukchi Sea were in a stationary growth phase under nutrient deficient condition based on biological and environmental conditions observed during our study period. Based on comparison with the previous studies in the northern Bering Sea and southern Chukchi Sea, we found that the photosynthetic carbon allocation patterns depending on physiological status of phytoplankton under the different growth and/or nutrient conditions could be largely vary at different regions in the Arctic Ocean. More intensive research on the physiological status of phytoplankton is further required to determine how phytoplankton response to the changing environmental conditions and consequently how they impact on higher trophic levels in marine ecosystems in the Arctic Ocean.

Phloem proteomics reveals new lipid-binding proteins with a putative role in lipid-mediated signaling

DOE PAGES

Barbaglia, Allison M.; Tamot, Banita; Greve, Veronica; ...

2016-04-28

Global climate changes inversely affect our ability to grow the food required for an increasing world population. To combat future crop loss due to abiotic stress, we need to understand the signals responsible for changes in plant development and the resulting adaptations, especially the signaling molecules traveling long-distance through the plant phloem. Using a proteomics approach, we had identified several putative lipid-binding proteins in the phloem exudates. Simultaneously, we identified several complex lipids as well as jasmonates. These findings prompted us to propose that phloem (phospho-) lipids could act as long-distance developmental signals in response to abiotic stress, and thatmore » they are released, sensed, and moved by phloem lipid-binding proteins (Benning et al., 2012). Indeed, the proteins we identified include lipases that could release a signaling lipid into the phloem, putative receptor components, and proteins that could mediate lipid-movement. To test this possible protein-based lipid-signaling pathway, three of the proteins, which could potentially act in a relay, are characterized here: (I) a putative GDSL-motif lipase (II) a PIG-P-like protein, with a possible receptor-like function; (III) and PLAFP (phloem lipid-associated family protein), a predicted lipid-binding protein of unknown function. Here we show that all three proteins bind lipids, in particular phosphatidic acid (PtdOH), which is known to participate in intracellular stress signaling. Genes encoding these proteins are expressed in the vasculature, a prerequisite for phloem transport. Cellular localization studies show that the proteins are not retained in the endoplasmic reticulum but surround the cell in a spotted pattern that has been previously observed with receptors and plasmodesmatal proteins. Abiotic signals that induce the production of PtdOH also regulate the expression of GDSL-lipase and PLAFP, albeit in opposite patterns. Our findings suggest that while all three proteins are indeed lipid-binding and act in the vasculature possibly in a function related to long-distance signaling, the three proteins do not act in the same but rather in distinct pathways. Furthermore, it points toward PLAFP as a prime candidate to investigate long-distance lipid signaling in the plant drought response.« less

Phloem proteomics reveals new lipid-binding proteins with a putative role in lipid-mediated signaling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barbaglia, Allison M.; Tamot, Banita; Greve, Veronica

Global climate changes inversely affect our ability to grow the food required for an increasing world population. To combat future crop loss due to abiotic stress, we need to understand the signals responsible for changes in plant development and the resulting adaptations, especially the signaling molecules traveling long-distance through the plant phloem. Using a proteomics approach, we had identified several putative lipid-binding proteins in the phloem exudates. Simultaneously, we identified several complex lipids as well as jasmonates. These findings prompted us to propose that phloem (phospho-) lipids could act as long-distance developmental signals in response to abiotic stress, and thatmore » they are released, sensed, and moved by phloem lipid-binding proteins (Benning et al., 2012). Indeed, the proteins we identified include lipases that could release a signaling lipid into the phloem, putative receptor components, and proteins that could mediate lipid-movement. To test this possible protein-based lipid-signaling pathway, three of the proteins, which could potentially act in a relay, are characterized here: (I) a putative GDSL-motif lipase (II) a PIG-P-like protein, with a possible receptor-like function; (III) and PLAFP (phloem lipid-associated family protein), a predicted lipid-binding protein of unknown function. Here we show that all three proteins bind lipids, in particular phosphatidic acid (PtdOH), which is known to participate in intracellular stress signaling. Genes encoding these proteins are expressed in the vasculature, a prerequisite for phloem transport. Cellular localization studies show that the proteins are not retained in the endoplasmic reticulum but surround the cell in a spotted pattern that has been previously observed with receptors and plasmodesmatal proteins. Abiotic signals that induce the production of PtdOH also regulate the expression of GDSL-lipase and PLAFP, albeit in opposite patterns. Our findings suggest that while all three proteins are indeed lipid-binding and act in the vasculature possibly in a function related to long-distance signaling, the three proteins do not act in the same but rather in distinct pathways. Furthermore, it points toward PLAFP as a prime candidate to investigate long-distance lipid signaling in the plant drought response.« less

Comprehensive Lipidome-Wide Profiling Reveals Dynamic Changes of Tea Lipids during Manufacturing Process of Black Tea.

PubMed

Li, Jia; Hua, Jinjie; Zhou, Qinghua; Dong, Chunwang; Wang, Jinjin; Deng, Yuliang; Yuan, Haibo; Jiang, Yongwen

2017-11-22

As important biomolecules in Camellia sinensis L., lipids undergo substantial changes during black tea manufacture, which is considered to contribute to tea sensory quality. However, limited by analytical capacity, detailed lipid composition and its dynamic changes during black tea manufacture remain unclear. Herein, we performed tea lipidome profiling using high resolution liquid chromatography coupled to mass spectrometry (LC-MS), which allows simultaneous and robust analysis of 192 individual lipid species in black tea, covering 17 (sub)classes. Furthermore, dynamic changes of tea lipids during black tea manufacture were investigated. Significant alterations of lipid pattern were revealed, involved with chlorophyll degradation, metabolic pathways of glycoglycerolipids, and other extraplastidial membrane lipids. To our knowledge, this report presented most comprehensive coverage of lipid species in black tea. This study provides a global and in-depth metabolic map of tea lipidome during black tea manufacture.

DNA concentration modulation on supported lipid bilayers switched by surface acoustic waves.

PubMed

Hennig, Martin; Wolff, Manuel; Neumann, Jürgen; Wixforth, Achim; Schneider, Matthias F; Rädler, Joachim O

2011-12-20

Spatially addressable arrays of molecules embedded in or anchored to supported lipid bilayers are important for on-chip screening and binding assays; however, methods to sort or accumulate components in a fluid membrane on demand are still limited. Here we apply in-plane surface acoustic shear waves (SAWs) to laterally accumulate double-stranded DNA segments electrostatically bound to a cationic supported lipid bilayer. The fluorescently labeled DNA segments are found to segregate into stripe patterns with a spatial frequency corresponding to the periodicity of the standing SAW wave (~10 μm). The DNA molecules are accumulated 10-fold in the regions of SAW antinodes. The superposition of two orthogonal sets of SAW sources creates checkerboard like arrays of DNA demonstrating the potential to generate arrayed fields dynamically. The pattern relaxation time of 0.58 s, which is independent of the segment length, indicates a sorting and relaxation mechanism dominated by lipid diffusion rather than DNA self-diffusion. © 2011 American Chemical Society

Occurrence of amylose-lipid complexes in teff and maize starch biphasic pastes.

PubMed

Wokadala, Obiro Cuthbert; Ray, Suprakas Sinha; Emmambux, Mohammad Naushad

2012-09-01

The occurrence of amylose-lipid complexes was determined in maize and teff starch biphasic pastes i.e. peak viscosity pastes at short and prolonged pasting times. Maize and teff starches were pasted for 11.5 and 130 min with or without added stearic acid followed by thermo-stable alpha-amylase hydrolysis in a rapid visco-analyzer. X-ray diffraction analysis of pastes before and residues after hydrolysis showed crystalline V-amylose diffraction patterns for the starches pasted for a prolonged time with added stearic acid while less distinct V-amylose patterns with non-complexed stearic acid peaks were observed with a short pasting time. Differential scanning calorimetry of pastes before and residues after paste hydrolysis showed that Type I amylose-lipid complexes were formed after pasting for the short duration with added stearic acid, while Type II complexes are formed after pasting for the prolonged time. The present research provides evidence that amylose-lipid complexes play an important role in starch biphasic pasting. Copyright © 2012 Elsevier Ltd. All rights reserved.

A Snack Dietary Pattern Increases the Risk of Hypercholesterolemia in Northern Chinese Adults: A Prospective Cohort Study

PubMed Central

Na, Lixin; Han, Tianshu; Zhang, Wei; Wu, Xiaoyan; Na, Guanqiong; Du, Shanshan; Li, Ying; Sun, Changhao

2015-01-01

The evidence about the effect of dietary patterns on blood cholesterol from cohort studies was very scarce. The study was to identify the association of dietary patterns with lipid profile, especially cholesterol, in a cohort in north China. Using a 1-year food frequency questionnaire, we assessed the dietary intake of 4515 adults from the Harbin People’s Health Study in 2008, aged 20-74 years. Principle component analysis was used to identify dietary patterns. The follow-up was completed in 2012. Fasting blood samples were collected for the determination of blood lipid concentrations. Logistic regression models were used to evaluate the association of dietary patterns with the incidence of hypercholesterolemia, hypertriglyceridemia, and low-HDL cholesterolemia. Five dietary patterns were identified (“staple food”, “vegetable, fruit and milk”, “potato, soybean and egg”, “snack”, and “meat”). The relative risk (RR) between the extreme tertiles of the snack dietary pattern scores was 1.72 (95% CI = 1.14, 2.59, P = 0.004) for hypercholesterolemia, 1.39 (1.13, 1.75, P = 0.036) for hypertriglyceridemia, after adjustment for age, sex, education, body mass index, smoking, alcohol consumption, energy intake, exercise and baseline lipid concentrations. There was a significant positive association between the snack dietary pattern scores and fasting serum total cholesterol (SRC (standardized regression coefficient) = 0.262, P = 0.025), LDL-c (SRC = 0.324, P = 0.002) and triglycerides (SRC = 0.253, P = 0.035), after adjustment for the multiple variables above. Moreover, the adjusted RR of hypertriglyceridemia between the extreme tertiles was 0.73 (0.56, 0.94, P = 0.025) for the vegetable, fruit and milk dietary pattern, and 1.86 (1.33, 2.41, P = 0.005) for the meat dietary pattern. The snack dietary pattern was a newly emerged dietary pattern in northern Chinese adults. It appears conceivable that the risk of hypercholesterolemia can be reduced by changing the snack dietary pattern. PMID:26244510

A Snack Dietary Pattern Increases the Risk of Hypercholesterolemia in Northern Chinese Adults: A Prospective Cohort Study.

PubMed

Na, Lixin; Han, Tianshu; Zhang, Wei; Wu, Xiaoyan; Na, Guanqiong; Du, Shanshan; Li, Ying; Sun, Changhao

2015-01-01

The evidence about the effect of dietary patterns on blood cholesterol from cohort studies was very scarce. The study was to identify the association of dietary patterns with lipid profile, especially cholesterol, in a cohort in north China. Using a 1-year food frequency questionnaire, we assessed the dietary intake of 4515 adults from the Harbin People's Health Study in 2008, aged 20-74 years. Principle component analysis was used to identify dietary patterns. The follow-up was completed in 2012. Fasting blood samples were collected for the determination of blood lipid concentrations. Logistic regression models were used to evaluate the association of dietary patterns with the incidence of hypercholesterolemia, hypertriglyceridemia, and low-HDL cholesterolemia. Five dietary patterns were identified ("staple food", "vegetable, fruit and milk", "potato, soybean and egg", "snack", and "meat"). The relative risk (RR) between the extreme tertiles of the snack dietary pattern scores was 1.72 (95% CI = 1.14, 2.59, P = 0.004) for hypercholesterolemia, 1.39 (1.13, 1.75, P = 0.036) for hypertriglyceridemia, after adjustment for age, sex, education, body mass index, smoking, alcohol consumption, energy intake, exercise and baseline lipid concentrations. There was a significant positive association between the snack dietary pattern scores and fasting serum total cholesterol (SRC (standardized regression coefficient) = 0.262, P = 0.025), LDL-c (SRC = 0.324, P = 0.002) and triglycerides (SRC = 0.253, P = 0.035), after adjustment for the multiple variables above. Moreover, the adjusted RR of hypertriglyceridemia between the extreme tertiles was 0.73 (0.56, 0.94, P = 0.025) for the vegetable, fruit and milk dietary pattern, and 1.86 (1.33, 2.41, P = 0.005) for the meat dietary pattern. The snack dietary pattern was a newly emerged dietary pattern in northern Chinese adults. It appears conceivable that the risk of hypercholesterolemia can be reduced by changing the snack dietary pattern.

Recent Advances in Lipid-Based Vesicles and Particulate Carriers for Topical and Transdermal Application.

PubMed

Jain, Shashank; Patel, Niketkumar; Shah, Mansi K; Khatri, Pinak; Vora, Namrata

2017-02-01

In the recent decade, skin delivery (topical and transdermal) has gained an unprecedented popularity, especially due to increased incidences of chronic skin diseases, demand for targeted and patient compliant delivery, and interest in life cycle management strategies among pharmaceutical companies. Literature review of recent publications indicates that among various skin delivery systems, lipid-based delivery systems (vesicular carriers and lipid particulate systems) have been the most successful. Vesicular carriers consist of liposomes, ultradeformable liposomes, and ethosomes, while lipid particulate systems consist of lipospheres, solid lipid nanoparticles, and nanostructured lipid carriers. These systems can increase the skin drug transport by improving drug solubilization in the formulation, drug partitioning into the skin, and fluidizing skin lipids. Considering that lipid-based delivery systems are regarded as safe and efficient, they are proving to be an attractive delivery strategy for the pharmaceutical as well as cosmeceutical drug substances. However, development of these delivery systems requires comprehensive understanding of physicochemical characteristics of drug and delivery carriers, formulation and process variables, mechanism of skin delivery, recent technological advancements, specific limitations, and regulatory considerations. Therefore, this review article encompasses recent research advances addressing the aforementioned issues. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Patterns of DNA Methylation Across the Leptin Core Promoter in Four Diverse Asian and North American Populations.

PubMed

Mosher, M J; Melton, P E; Stapleton, P; Schanfield, M S; Crawford, M H

2016-04-01

DNA methylation is the most widely studied of epigenetic mechanisms, with environmental effects recorded through patterned attachments of methyl groups along the DNA that are capable of modifying gene expression without altering the DNA sequencing. The degree to which these patterns of DNA methylation are heritable, the expected range of normality across populations, and the phenotypic relevance of pattern variation remain unclear. Genes regulating metabolic pathways appear to be vulnerable to ongoing nutritional programming over the life course, as dietary nutrients are significant environmental determinants of DNA methylation, supplying both the methyl groups and energy to generate the methylation process. Here we examine methylation patterns along a region of the metabolic gene leptin (LEP). LEP's putative functions include regulation of energy homeostasis, with its signals affecting energy intake and expenditure, adipogenesis and energy storage, lipid and glucose metabolism, bone metabolism, and reproductive endocrine function. A pattern of differential methylation across CpG sites of the LEP core promoter has been previously identified; however, any consistency of pattern or its phenotypic significance is not fully elucidated among populations. Using DNA extracted from unfractionated white blood cells of peripheral blood samples, our pilot study, divided into two parts, examined the significance of variation in DNA methylation patterns along the leptin core promoter in four populations (phase 1) and used biomarkers reflecting leptin's functional process in two of those populations, western Buryat of Siberia and the Mennonite of central Kansas, to investigate the relevance of the ethnic variation identified in the DNA methylation (phase 2). LEP's core promoter region contains both the binding site for C/EBPα (CCAAT/enhancer binding protein alpha), which tempers the final step in adipocyte maturity and capacity to synthesize leptin, and the TATA motif controlling leptin synthesis. Previous studies report that increased methylation in this region is correlated to decreased gene expression, suggesting tissue-specific methylation variation at this region ( Melzner et al. 2002 ). We hypothesized that evidence of nutritional epigenetic programming would be identified through variation in patterns of DNA methylation and that functional relevance of that variation among populations would be identified through biomarkers that reflect leptin's metabolic signals: serum leptin levels, lipoproteins of the lipid transport system, and anthropometric measures. In phase 1, our combined analyses of 313 individuals documented a distinct and consistent overall pattern of differential DNA methylation across seven CpG sites of LEP core promoter in all ethnicities and both sexes. This pattern replicates those identified in previous studies, suggesting a conserved core promoter region across populations. Phase 2 analyses of two of the four populations (n = 239), correlating methylation at the C/EBPα transcription binding site (TBS) with metabolic and anthropometric biomarkers reflecting LEP roles, showed that stature, which reflects bone growth and remodeling, was significantly and inversely correlated with the percentage of DNA methylation at this site in both sexes. We suggest that variation in DNA methylation along the LEP core promoter plays a substantial role in energy signals affecting both adipogenesis and bone metabolism.

Egg components and hatchling lipid reserves: parental investment in kinosternid turtles from the southeastern United States.

PubMed

Nagle, R D; Burke, V J; Congdon, J D

1998-05-01

We measured egg components and pre-ovulatory parental investment in kinosternid turtles (Kinosternon baurii, Kinosternon subrubrum, Sternotherus minor, and Sternotherus odoratus) from the southeastern USA. Allocation patterns were determined by comparing lipid content of eggs and hatchlings, to determine whether females of species with hatchlings that exhibit a delayed nest-emergence strategy: (1) allocate higher proportions of energy storage lipids to eggs, (2) produce hatchlings with higher levels of storage lipids, and (3) have higher levels of pre-ovulatory parental investment in comparison to species whose hatchlings exhibit immediate emergence. Whereas total non-polar lipid (NPL) proportions by dry mass of eggs varied significantly among species, NPL proportions of hatchlings were not significantly different. Pre-ovulatory parental investment in care (proportion of hatchling NPL to egg NPL) was 40, 50, and 55% for K. subrubrum, S. minor, and S. odoratus, respectively. Lipid class composition of eggs and hatchlings was studied to distinguish lipids allocated for energy storage from those allocated to other functions. For both eggs and hatchlings, individual lipid classes (triacylglycerol, triacylglycerol fatty acid, cholesterol, cholesterol ester, and phospholipid) as proportions of total lipid, were similar among species. The major lipid class component of eggs and hatchlings of all species was triacylglycerol (> 83%), an energy storage lipid. Substantial changes in lipid classes during embryogenesis were similar among species and included: (1) depletion of triacylglycerol, (2) increase in cholesterol esters, and (3) changes in phospholipid composition. Incubation time varied significantly among species, and appeared to be responsible for differential energy utilization during embryogenesis. Our results are inconsistent with the previously observed pattern that hatchlings exhibiting a delayed nest-emergence strategy are allocated higher proportions of energy storage lipids than those that exhibit immediate emergence. However, because the species that overwinters in the nest (K. subrubrum) hatches approximately 40 days later than the species that typically does not (S. odoratus), hatchling K. subrubrum may contain higher non-polar lipid proportions than hatchling S. odoratus during similar winter time periods. Kinosternid hatchlings contain enough stored lipids to support basal maintenance costs for substantial time periods. We suggest that such reserves may be critical to hatchling survival during a period of negative energy balance, regardless of nest emergence strategy.

Large-scale transcriptome analysis reveals arabidopsis metabolic pathways are frequently influenced by different pathogens.

PubMed

Jiang, Zhenhong; He, Fei; Zhang, Ziding

2017-07-01

Through large-scale transcriptional data analyses, we highlighted the importance of plant metabolism in plant immunity and identified 26 metabolic pathways that were frequently influenced by the infection of 14 different pathogens. Reprogramming of plant metabolism is a common phenomenon in plant defense responses. Currently, a large number of transcriptional profiles of infected tissues in Arabidopsis (Arabidopsis thaliana) have been deposited in public databases, which provides a great opportunity to understand the expression patterns of metabolic pathways during plant defense responses at the systems level. Here, we performed a large-scale transcriptome analysis based on 135 previously published expression samples, including 14 different pathogens, to explore the expression pattern of Arabidopsis metabolic pathways. Overall, metabolic genes are significantly changed in expression during plant defense responses. Upregulated metabolic genes are enriched on defense responses, and downregulated genes are enriched on photosynthesis, fatty acid and lipid metabolic processes. Gene set enrichment analysis (GSEA) identifies 26 frequently differentially expressed metabolic pathways (FreDE_Paths) that are differentially expressed in more than 60% of infected samples. These pathways are involved in the generation of energy, fatty acid and lipid metabolism as well as secondary metabolite biosynthesis. Clustering analysis based on the expression levels of these 26 metabolic pathways clearly distinguishes infected and control samples, further suggesting the importance of these metabolic pathways in plant defense responses. By comparing with FreDE_Paths from abiotic stresses, we find that the expression patterns of 26 FreDE_Paths from biotic stresses are more consistent across different infected samples. By investigating the expression correlation between transcriptional factors (TFs) and FreDE_Paths, we identify several notable relationships. Collectively, the current study will deepen our understanding of plant metabolism in plant immunity and provide new insights into disease-resistant crop improvement.

Process strategies for high titers of lipid production by oleaginous yeasts in undetoxified hydrolyzates of lignocellulosic biomass

USDA-ARS?s Scientific Manuscript database

Oleaginous yeasts can accumulate up to 70% of cell biomass as lipid, predominantly as triacylglycerols. Yeast lipid fatty acid profiles have been reported to be similar to that of vegetable oils and consist primarily of oleic, palmitic, stearic, and linoleic acids. This capability provides the oppor...

Process strategies to maximize lipid accumulations of novel yeast in acid and base treated hydrolyzates

USDA-ARS?s Scientific Manuscript database

Oleaginous yeasts can accumulate up to 70% of cell biomass as lipids, predominantly as triacylglycerols. Yeast lipid fatty acid profiles have been reported to be similar to that of vegetable oils and consist primarily of oleic, palmitic, stearic, and linoleic acids. This capability provides the oppo...

Cooking increases net energy gain from a lipid-rich food.

PubMed

Groopman, Emily E; Carmody, Rachel N; Wrangham, Richard W

2015-01-01

Starch, protein, and lipid are three major sources of calories in the human diet. The unique and universal human practice of cooking has been demonstrated to increase the energy gained from foods rich in starch or protein. Yet no studies have tested whether cooking has equivalent effects on the energy gained from lipid-rich foods. Using mice as a model, we addressed this question by examining the impact of cooking on the energy gained from peanuts, a lipid-rich oilseed, and compared this impact against that of nonthermal processing (blending). We found that cooking consistently increased the energy gained per calorie, whereas blending had no detectable energetic benefits. Assessment of fecal fat excretion showed increases in lipid digestibility when peanuts were cooked, and examination of diet microstructure revealed concomitant alterations to the integrity of cell walls and the oleosin layer of proteins that otherwise shield lipids from digestive lipases. Both effects were consistent with the greater energy gain observed with cooking. Our findings highlight the importance of cooking in increasing dietary energy returns for humans, both past and present. © 2014 Wiley Periodicals, Inc.

Arabidopsis ribosomal proteins control vacuole trafficking and developmental programs through the regulation of lipid metabolism.

PubMed

Li, Ruixi; Sun, Ruobai; Hicks, Glenn R; Raikhel, Natasha V

2015-01-06

The vacuole is the most prominent compartment in plant cells and is important for ion and protein storage. In our effort to search for key regulators in the plant vacuole sorting pathway, ribosomal large subunit 4 (rpl4d) was identified as a translational mutant defective in both vacuole trafficking and normal development. Polysome profiling of the rpl4d mutant showed reduction in polysome-bound mRNA compared with wild-type, but no significant change in the general mRNA distribution pattern. Ribsomal profiling data indicated that genes in the lipid metabolism pathways were translationally down-regulated in the rpl4d mutant. Live imaging studies by Nile red staining suggested that both polar and nonpolar lipid accumulation was reduced in meristem tissues of rpl4d mutants. Pharmacological evidence showed that sterol and sphingolipid biosynthetic inhibitors can phenocopy the defects of the rpl4d mutant, including an altered vacuole trafficking pattern. Genetic evidence from lipid biosynthetic mutants indicates that alteration in the metabolism of either sterol or sphingolipid biosynthesis resulted in vacuole trafficking defects, similar to the rpl4d mutant. Tissue-specific complementation with key enzymes from lipid biosynthesis pathways can partially rescue both vacuole trafficking and auxin-related developmental defects in the rpl4d mutant. These results indicate that lipid metabolism modulates auxin-mediated tissue differentiation and endomembrane trafficking pathways downstream of ribosomal protein function.

The effect of repeated lateral compression and expansions mimicking blinking on selected tear film polar lipid monofilms.

PubMed

Patterson, Matthew; Vogel, Hans J; Prenner, Elmar J

2017-03-01

The tear film lipid layer is formed on the anterior surface of the eye, functioning as a barrier to excess evaporation and foreign particles, while also providing stability to the tear film. The lipid layer is organized into a polar lipid layer consisting of phospholipids, ceramides, and free fatty acids that act as a surfactant to a non-polar multilayer of wax and cholesterol esters. Due to shear forces from eye movement and the compression and expansion of blinking, the tear lipids are under constant stress. However, tear film is able to resist immediate rupture and remains intact over multiple blinks. This work aimed to better understand the lateral organization of selected tear film polar lipids. The polar lipid biomimetic studied here consisted of dipalmitoyl phosphatidylcholine (DPPC), dipalmitoyl phosphatidylethanolamine (DPPE), palmitoyl glucosylceramide (PGC), and palmitoyl sphingomyelin (PSM). Surface pressure-area isocycles mimicked blinking and films were visualized by Brewster angle microscopy (BAM). All lipid systems formed relatively reversible films as indicated by limited hysteresis. However, pure DPPC and PSM films experienced greater changes in lipid packing upon compression and expansion compared to pure PGC and DPPE. This suggests that the driving force behind maintaining the lateral organization of the polar lipids from tear film may be the hydrogen bonding propensities of the head groups. Additionally, isocycles of films containing DPPC, DPPE, and PGC mixtures exhibited evidence for reversible multilayer formation or folding. This was supported by 3D analysis of structures that formed during compression but reintegrated back into the bulk lipid film during expansion near the in vitro tear film surface pressure of the open eye. Therefore, the polar lipids of tear film may be directly involved in preventing film rupture during a blink. Copyright © 2016 Elsevier B.V. All rights reserved.

Using a patterned grating structure to create lipid bilayer platforms insensitive to air bubbles.

PubMed

Han, Chung-Ta; Chao, Ling

2015-01-07

Supported lipid bilayers (SLBs) have been used for various biosensing applications. The bilayer structure enables embedded lipid membrane species to maintain their native orientation, and the two-dimensional fluidity is crucial for numerous biomolecular interactions to occur. The platform integrated with a microfluidic device for reagent transport and exchange has great potential to be applied with surface analytical tools. However, SLBs can easily be destroyed by air bubbles during assay reagent transport and exchange. Here, we created a patterned obstacle grating structured surface in a microfluidic channel to protect SLBs from being destroyed by air bubbles. Unlike all of the previous approaches using chemical modification or adding protection layers to strengthen lipid bilayers, the uniqueness of this approach is that it uses the patterned obstacles to physically trap water above the bilayers to prevent the air-water interface from directly coming into contact with and peeling the bilayers. We showed that our platform with certain grating geometry criteria can provide promising protection to SLBs from air bubbles. The required obstacle distance was found to decrease when we increased the air-bubble movement speed. In addition, the interaction assay results from streptavidin and biotinylated lipids in the confined SLBs suggested that receptors at the SLBs retained the interaction ability after air-bubble treatment. The results showed that the developed SLB platform can preserve both high membrane fluidity and high accessibility to the outside environment, which have never been simultaneously achieved before. Incorporating the built platforms with some surface analytical tools could open the bottleneck of building highly robust in vitro cell-membrane-related bioassays.

Investigation of the phase morphology of bacterial PHA inclusion bodies by contrast variation SANS

NASA Astrophysics Data System (ADS)

Russell, R. A.; Holden, P. J.; Garvey, C. J.; Wilde, K. L.; Hammerton, K. M.; Foster, L. J.

2006-11-01

Under growth-limiting conditions, many bacteria are able to metabolise excess organic acids into polyhydroxyalkanoates (PHA) and store these polymers as intracellular inclusions until the return of favourable conditions. Various models have been proposed for the macromolecular organisation of the boundary layer surrounding the polymer, and contrast-variation small-angle neutron scattering (SANS) was used to study its organisation. Inclusions formed by Pseudomonas oleovorans under hydrogenating conditions showed lowest scattering intensity at ca. 20% D 2O. The inclusions consist of protein and membrane lipids in the boundary layer and polyhydroxyoctanoate (lipid) in the inclusion body. At 20% D 2O the contributions of lipids were contrast matched with the solvent, indicating that lipids contributed the bulk of the scattering intensity observed at other D 2O/H 2O ratios. These results are inconsistent with a model of the boundary layer which proposed outer and inner layers of crystalline protein lattice sandwiching a membrane lipid membrane layer [E.S. Stuart, R.W. Lenz, R.C. Fuller, Can J Microbiol 41(Suppl 1) (1995) 84-93], and is more consistent with a model consisting of a lipid monolayer containing embedded proteins [U. Pieper-furst, M.H. Madkour, F. Mayer, A. Steinbuchel, J. Bacteriol. 176 (1994) 4328-4337.] By altering the H/D content of the precursors, we were able to collect SANS data from preparations of both deuterated and H/D copolymer inclusions, where initial PHA produced was hydrogenated followed by deuteration. Deuterated inclusions showed minimum intensity above 90% D 2O/H 2O whereas the sequentially produced copolymer (assumed to be in a core/shell arrangement) displayed minimum scattering some 20% lower, which is consistent with the increased hydrogenation of the boundary layer expected from its synthesis during supply of hydrogenated followed by deuterated precursors.

Innate signaling by mycobacterial cell wall components and relevance for development of adjuvants for subunit vaccines.

PubMed

Tima, Hermann Giresse; Huygen, Kris; Romano, Marta

2016-11-01

Pathogen recognition receptors (PRRs) recognize pathogen-associated molecular patterns, triggering the induction of inflammatory innate responses and contributing to the development of specific adaptive immune responses. Novel adjuvants have been developed based on agonists of PRRs. Areas covered: Lipid pathogen-associated molecular patterns (PAMPs) present in the cell wall of mycobacteria are revised, with emphasis on agonists of C-type lectin receptors, signaling pathways, and preclinical data supporting their use as novel adjuvants inducing cell-mediated immune responses. Their potential use as lipid antigens in novel tuberculosis subunit vaccines is also discussed. Expert commentary: Few adjuvants are licensed for human use and mainly favour antibody-mediated protective immunity. Use of lipid PAMPs that trigger cell-mediated immune responses could lead to the development of adjuvants for vaccines against intracellular pathogens and cancer.

Protein assembly and heat stability in developing thylakoid membranes during greening

PubMed Central

Kóta, Zoltán; Horváth, László I.; Droppa, Magdolna; Horváth, Gábor; Farkas, Tibor; Páli, Tibor

2002-01-01

The development of the thylakoid membrane was studied during illumination of dark-grown barley seedlings by using biochemical methods, and Fourier transform infrared and spin label electron paramagnetic resonance spectroscopic techniques. Correlated, gross changes in the secondary structure of membrane proteins, conformation, composition, and dynamics of lipid acyl chains, SDS/PAGE pattern, and thermally induced structural alterations show that greening is accompanied with the reorganization of membrane protein assemblies and the protein–lipid interface. Changes in overall membrane fluidity and noncovalent protein–lipid interactions are not monotonic, despite the monotonic accumulation of chlorophyll, LHCII [light-harvesting chlorophyll a/b-binding (polypeptides) associated with photosystem II] apoproteins, and 18:3 fatty acids that follow a similar time course with highest rates between 12–24 h of greening. The 18:3 fatty acid content increases 2.8-fold during greening. This appears to both compensate for lipid immobilization by membrane proteins and facilitate packing of larger protein assemblies. The increase in the amount of protein-solvating immobile lipids, which reaches a maximum at 12 h, is caused by 40% decrease in the membranous mean diameter of protein assemblies at constant protein/lipid mass ratio. Alterations in the SDS/PAGE pattern are most significant between 6–24 h. The size of membrane protein assemblies increases ≈4.5-fold over the 12–48-h period, likely caused by the 2-fold gain in LHCII apoproteins. The thermal stability of thylakoid membrane proteins increases monotonically, as detected by an increasing temperature of partial protein unfolding during greening. Our data suggest that a structural coupling between major protein and lipid components develops during greening. This protein–lipid interaction is required for the development and protection of thylakoid membrane protein assemblies. PMID:12213965

Carbon and Acyl Chain Flux during Stress-induced Triglyceride Accumulation by Stable Isotopic Labeling of the Polar Microalga Coccomyxa subellipsoidea C169*

PubMed Central

Allen, James W.; DiRusso, Concetta C.; Black, Paul N.

2017-01-01

Deriving biofuels and other lipoid products from algae is a promising future technology directly addressing global issues of atmospheric CO2 balance. To better understand the metabolism of triglyceride synthesis in algae, we examined their metabolic origins in the model species, Coccomyxa subellipsoidea C169, using stable isotopic labeling. Labeling patterns arising from [U-13C]glucose, 13CO2, or D2O supplementation were analyzed by GC-MS and/or LC-MS over time courses during nitrogen starvation to address the roles of catabolic carbon recycling, acyl chain redistribution, and de novo fatty acid (FA) synthesis during the expansion of the lipid bodies. The metabolic origin of stress-induced triglyceride was found to be a continuous 8:2 ratio between de novo synthesized FA and acyl chain transfer from pre-stressed membrane lipids with little input from lipid remodeling. Membrane lipids were continually synthesized with associated acyl chain editing during nitrogen stress, in contrast to an overall decrease in total membrane lipid. The incorporation rates of de novo synthesized FA into lipid classes were measured over a time course of nitrogen starvation. The synthesis of triglycerides, phospholipids, and galactolipids followed a two-stage pattern where nitrogen starvation resulted in a 2.5-fold increase followed by a gradual decline. Acyl chain flux into membrane lipids was dominant in the first stage followed by triglycerides. These data indicate that the level of metabolic control that determines acyl chain flux between membrane lipids and triglycerides during nitrogen stress relies primarily on the Kennedy pathway and de novo FA synthesis with limited, defined input from acyl editing reactions. PMID:27903654

Carbon and Acyl Chain Flux during Stress-induced Triglyceride Accumulation by Stable Isotopic Labeling of the Polar Microalga Coccomyxa subellipsoidea C169.

PubMed

Allen, James W; DiRusso, Concetta C; Black, Paul N

2017-01-06

Deriving biofuels and other lipoid products from algae is a promising future technology directly addressing global issues of atmospheric CO 2 balance. To better understand the metabolism of triglyceride synthesis in algae, we examined their metabolic origins in the model species, Coccomyxa subellipsoidea C169, using stable isotopic labeling. Labeling patterns arising from [U- 13 C]glucose, 13 CO 2 , or D 2 O supplementation were analyzed by GC-MS and/or LC-MS over time courses during nitrogen starvation to address the roles of catabolic carbon recycling, acyl chain redistribution, and de novo fatty acid (FA) synthesis during the expansion of the lipid bodies. The metabolic origin of stress-induced triglyceride was found to be a continuous 8:2 ratio between de novo synthesized FA and acyl chain transfer from pre-stressed membrane lipids with little input from lipid remodeling. Membrane lipids were continually synthesized with associated acyl chain editing during nitrogen stress, in contrast to an overall decrease in total membrane lipid. The incorporation rates of de novo synthesized FA into lipid classes were measured over a time course of nitrogen starvation. The synthesis of triglycerides, phospholipids, and galactolipids followed a two-stage pattern where nitrogen starvation resulted in a 2.5-fold increase followed by a gradual decline. Acyl chain flux into membrane lipids was dominant in the first stage followed by triglycerides. These data indicate that the level of metabolic control that determines acyl chain flux between membrane lipids and triglycerides during nitrogen stress relies primarily on the Kennedy pathway and de novo FA synthesis with limited, defined input from acyl editing reactions. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Favorable effect of optimal lipid-lowering therapy on neointimal tissue characteristics after drug-eluting stent implantation: qualitative optical coherence tomographic analysis.

PubMed

Jang, Ji-Yong; Kim, Jung-Sun; Shin, Dong-Ho; Kim, Byeong-Keuk; Ko, Young-Guk; Choi, Donghoon; Jang, Yangsoo; Hong, Myeong-Ki

2015-10-01

Serial follow-up optical coherence tomography (OCT) was used to evaluate the effect of optimal lipid-lowering therapy on qualitative changes in neointimal tissue characteristics after drug-eluting stent (DES) implantation. DES-treated patients (n = 218) who received statin therapy were examined with serial follow-up OCT. First and second follow-up OCT evaluations were performed approximately 6 and 18 months after the index procedure, respectively. Patients were divided into two groups, based on the level of low-density lipoprotein-cholesterol (LDL-C), which was measured at the second follow-up. The optimal lipid-lowering group (n = 121) had an LDL-C reduction of ≥50% or an LDL-C level ≤70 mg/dL, and the conventional group (n = 97). Neointimal characteristics were qualitatively categorized as homogeneous or non-homogeneous patterns using OCT. The non-homogeneous group included heterogeneous, layered, or neoatherosclerosis patterns. Qualitative changes in neointimal tissue characteristics between the first and second follow-up OCT examinations were assessed. Between the first and second follow-up OCT procedures, the neointimal cross-sectional area increased more substantially in the conventional group (0.4 mm(2) vs. 0.2 mm(2) in the optimal lipid-lowering group, p = 0.01). The neointimal pattern changed from homogeneous to non-homogeneous less often in the optimal lipid-lowering group (1.3%, 1/77, p < 0.001) than in the conventional group (15.3%, 11/72, p = 0.44). Optimal LDL-C reduction was an independent predictor for the prevention of neointimal pattern change from homogeneous to non-homogeneous (odds ratio: 0.05, 95% confidence interval: 0.01∼0.46, p = 0.008). Our findings suggest that an intensive reduction in LDL-C levels can prevent non-homogeneous changes in the neointima and increases in neointimal cross-sectional area compared with conventional LDL-C controls. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Structure-property relationships in a series of diglycerol tetraether model lipids and their lyotropic assemblies: the effect of branching topology and chirality.

PubMed

Markowski, Thomas; Drescher, Simon; Meister, Annette; Blume, Alfred; Dobner, Bodo

2014-06-14

Three novel diglycerol tetraether lipids with one membrane-spanning chain have been synthesized. These lipids contain only two or four racemic methyl branches at selected positions of the hydrophobic chains in contrast to natural lipids from archaebacterial membranes with an isoprenoid substitution pattern. The insertion of the methyl moieties was realized starting from either (RS)-citronellyl bromide or the inexpensive methyl malonic acid ethyl ester. For chain elongation the Cu-catalysed Grignard coupling reaction was used. The preparation of diglycerol tetraethers was either performed by condensing suitable blocked monoglycerol diethers by Grubbs metathesis or by reaction of the transmembrane C32-chain with blocked glycerols followed by further alkylation steps. Finally, we could show that the resulting lipids can form closed lipid vesicles comparable to the optically pure counterparts. Therefore, these much simpler lipids compared to the natural lipids from archaebacterial membranes are also suitable for preparation of stable tailored liposomes.

LC-ESI-MS/MS identification of polar lipids of two thermophilic Anoxybacillus bacteria containing a unique lipid pattern.

PubMed

Rezanka, Tomáš; Kambourova, Margarita; Derekova, Anna; Kolouchová, Irena; Sigler, Karel

2012-07-01

Phospholipids and glycolipids from two recently described species belonging to the thermophilic genus Anoxybacillus were analyzed by liquid chromatography-electrospray tandem mass spectrometry (LC/ESI-MS/MS). Analysis of total lipids from the facultatively anaerobic A. bogrovensis on a HILIC (Hydrophilic Interaction LIquid Chromatography) column succeeded in separating diacyl- and plasmalogen phospholipids. The LC/ESI-MS/MS analysis of the strict aerobe A. rupiensis revealed the presence of different unique polar lipids, predominantly alanyl-, lysyl-, and glucosyl-phosphatidylglycerols and cardiolipins. Each of the classes of polar lipids was then analyzed by means of the ESI-MS/MS and more than 140 molecular species of six lipid classes from A. bogrovensis and nearly 200 molecular species of nine classes of polar lipids from A. rupiensis were identified. Five classes of unidentified polar lipids were detected in both strains. Plasmalogens were thus determined for the first time in a facultatively anaerobic bacterium, i.e. A. bogrovensis.

Lipid14: The Amber Lipid Force Field

PubMed Central

2015-01-01

The AMBER lipid force field has been updated to create Lipid14, allowing tensionless simulation of a number of lipid types with the AMBER MD package. The modular nature of this force field allows numerous combinations of head and tail groups to create different lipid types, enabling the easy insertion of new lipid species. The Lennard-Jones and torsion parameters of both the head and tail groups have been revised and updated partial charges calculated. The force field has been validated by simulating bilayers of six different lipid types for a total of 0.5 μs each without applying a surface tension; with favorable comparison to experiment for properties such as area per lipid, volume per lipid, bilayer thickness, NMR order parameters, scattering data, and lipid lateral diffusion. As the derivation of this force field is consistent with the AMBER development philosophy, Lipid14 is compatible with the AMBER protein, nucleic acid, carbohydrate, and small molecule force fields. PMID:24803855

Ordering Transitions in Liquid Crystals Permit Imaging of Spatial and Temporal Patterns Formed by Proteins Penetrating into Lipid-Laden Interfaces

PubMed Central

Daschner De Tercero, Maren; Abbott, Nicholas L.

2013-01-01

Recent studies have reported that full monolayers of L-α-dilaurylphosphatidylcholine (L-DLPC) and D-α-dipalmitoylphosphatidylcholine (D-DPPC) formed at interfaces between thermotropic liquid crystals (LCs) and aqueous phases lead to homeotropic (perpendicular) orientations of nematic LCs and that specific binding of proteins to these interfaces (such as phospholipase A2 binding to D-DPPC) can trigger orientational ordering transitions in the liquid crystals. We report on the nonspecific interactions of proteins with aqueous-LC interfaces decorated with partial monolayer coverage of L-DLPC. Whereas nonspecific interactions of four proteins (cytochrome c, bovine serum albumin,immunoglobulins, and neutravidin) do not perturb the ordering of the LC when a full monolayer of L-DLPC is assembled at the aqueous-LC interface, we observe patterned orientational transitions in the LC that reflect penetration of proteins into the interface of the LC with partial monolayer coverage of L-DLPC. The spatial patterns formed by the proteins and lipids at the interface are surprisingly complex, and in some cases the protein domains are found to compartmentalize lipid within the interfaces. These results suggest that phospholipid-decorated interfaces between thermotropic liquid crystals and aqueous phases offer the basis of a simple and versatile tool to study the spatial organization and dynamics ofprotein networks formed at mobile, lipid-decorated interfaces. PMID:23671353

Structure, stability, and thermodynamics of lamellar DNA-lipid complexes.

PubMed Central

Harries, D; May, S; Gelbart, W M; Ben-Shaul, A

1998-01-01

We develop a statistical thermodynamic model for the phase evolution of DNA-cationic lipid complexes in aqueous solution, as a function of the ratios of charged to neutral lipid and charged lipid to DNA. The complexes consist of parallel strands of DNA intercalated in the water layers of lamellar stacks of mixed lipid bilayers, as determined by recent synchrotron x-ray measurements. Elastic deformations of the DNA and the lipid bilayers are neglected, but DNA-induced spatial inhomogeneities in the bilayer charge densities are included. The relevant nonlinear Poisson-Boltzmann equation is solved numerically, including self-consistent treatment of the boundary conditions at the polarized membrane surfaces. For a wide range of lipid compositions, the phase evolution is characterized by three regions of lipid to DNA charge ratio, rho: 1) for low rho, the complexes coexist with excess DNA, and the DNA-DNA spacing in the complex, d, is constant; 2) for intermediate rho, including the isoelectric point rho = 1, all of the lipid and DNA in solution is incorporated into the complex, whose inter-DNA distance d increases linearly with rho; and 3) for high rho, the complexes coexist with excess liposomes (whose lipid composition is different from that in the complex), and their spacing d is nearly, but not completely, independent of rho. These results can be understood in terms of a simple charging model that reflects the competition between counterion entropy and inter-DNA (rho < 1) and interbilayer (rho > 1) repulsions. Finally, our approach and conclusions are compared with theoretical work by others, and with relevant experiments. PMID:9649376

Chemical Patterning by Mechanical Removal of Aqueous Polymers

NASA Astrophysics Data System (ADS)

Barnett, Katherine; Knoebel, Jodi; Davis, Robert C.

2006-10-01

We are developing a new method for micro and nanoscale patterning of lipids and proteins on solid surfaces. A layer of polyethylene glycol (PEG) teminated polyallyl amine (PAA) was initially applied to a mica surface. The PEG surface is a low adhesion surface for proteins. Following polymer deposition an Atomic Force Microscope (AFM) tip was used to remove the polymer layer in desired regions. AFM imaging of the surface after mechanical polymer removal shows squares of exposed MICA surrounded by the PEG surface. The clean mica regions are now available for specific adsorption of lipid or protein layers.

Supercritical fluid extraction and characterization of lipids from algae Scenedesmus obliquus

NASA Technical Reports Server (NTRS)

Choi, K. J.; Nakhost, Z.; Krukonis, V. J.; Karel, M.

1987-01-01

Lipids were extracted from a protein concentrate of green algae (Scenedesmus obliquus), using a one-step supercritical carbon dioxide extraction procedure in presence of ethanol as an entrainer, and were characterized. The compositions of neutral lipids, glycolipids, and phospholipids, separated into individual components by column, thin-layer, and gas-liquid chromatography procedures, are presented. Fatty acid composition patterns indicated that the major fatty acids were 16:0, 16:1, 16:2, 16:3, 16:4, 18:1, 18:2, and 18:3. The lipids of S. obliquus were found to contain relatively high concentrations of polyunsaturated fatty acids and essential fatty acids.

Short-term and mid-term effects of fasting and downset meal pattern on lipid profile in Iranian fasted women.

PubMed

Rabiee, Samira; Afghari, Narsis; Rastmanesh, Reza

2014-06-01

It is not clear that whether the effects of fasting and downset meal pattern on lipid profile are limited only to Ramadan or do they remain after that month. The cohort study was conducted on 49 women aged 20-45 who worked at Shahid Motahari hospital in Isfahan. They put on groups of 23 consuming downset meal and 26 non-consuming downset meal persons. Serum triglyceride, cholesterol, LDL, and HDL were measured on the 3 days before the beginning, 3 and 30 days after the end of Ramadan. Repeated measure test was used to determine the changes during times and the interaction effects between times and nocturnal eating pattern. This study showed that fasting causes some short-term and mid-term changes in triglyceride and HDL that is mostly attributable to changes in dietary habits during Ramadan, rather than downset meal pattern.

LipidPioneer: A Comprehensive User-Generated Exact Mass Template for Lipidomics

PubMed Central

Ulmer, Candice Z.; Koelmel, Jeremy P.; Ragland, Jared M.; Garrett, Timothy J.

2017-01-01

Lipidomics, the comprehensive measurement of lipid species in a biological system, has promising potential in biomarker discovery and disease etiology elucidation. Advances in chromatographic separation, mass spectrometric techniques, and novel substrate applications continue to expand the number of lipid species observed. The total number and type of lipid species detected in a given sample are generally indicative of the sample matrix examined (e.g. serum, plasma, cells, bacteria, tissue, etc.). Current exact mass lipid libraries are static and represent the most commonly analyzed matrices. It is common practice for users to manually curate their own lists of lipid species and adduct masses; however, this process is time-consuming. LipidPioneer, an interactive template, can be used to generate exact masses and molecular formulas of lipid species that may be encountered in the mass spectrometric analysis of lipid profiles. Over 60 lipid classes are present in the LipidPioneer template, and include several unique lipid species, such as ether-linked lipids and lipid oxidation products. In the template, users can add any fatty acyl constituents without limitation in the number of carbons or degrees of unsaturation. LipidPioneer accepts naming using the lipid class level (sum composition) and the LIPID MAPS notation for fatty acyl structure level. In addition to lipid identification, user generated lipid m/z values can be used to develop inclusion lists for targeted fragmentation experiments. Resulting lipid names and m/z values can be imported into software such as MZmine or Compound Discoverer to automate exact mass searching and isotopic pattern matching across experimental data. PMID:28074328

Lipid extraction of wet BLT0404 microalgae for biofuel application

NASA Astrophysics Data System (ADS)

Mansur, Dieni; Fitriady, Muhammad Arifuddin; Susilaningsih, Dwi; Simanungkalit, Sabar Pangihutan; Agustian, Egi

2017-01-01

Recently, research and development of microalgae for biodiesel production were conducted by researchers in the world. This research becomes popular because of an exponential growth of the microalgae under nutrient limitation. Lipid of microalgae grows faster than oil producing land crops. Therefore, microalgae lipid content could improve the economics of biodiesel production. The aim of this study was to investigate yield of lipid extract and chemicals compounds containing in non-acylglycerol neutral lipid from BLT 0404 microalga. The study was conducted because lipid extraction was an important step for biodiesel as well as biofuel production. The extraction was carried out using polar and non-polar mixture solvents. The polar solvent was methanol and non-polar one was chloroform. Process extraction was conducted under various stirring time between the microalgae and methanol and volume ratio between the methanol and chloroform. Methanol as a polar solvent was able to extract polar lipid (phospholipid and glycolipid) because it removed polar membrane lipid and lipid-associated to polar molecule. Moreover, the non-polar solvent was used for extraction non-acylglycerol neutral lipid (hydrocarbons, sterols, ketones, free fatty acids, carotenes, and chlorophylls) for biofuel production. Under ratio of microalgae: methanol: chloroform of 0.8: 4: 2 that stirring time of the microalgae with methanol was 30 min yielded 58% of total lipid extract. The yield value consisted of 14.5% of non-acylglycerol neutral lipid and 43.5% of polar lipid. The non-acylglycerol neutral lipid will be converted into biofuel. Therefore, analysis of its chemical compounds was required. The non-acylglycerol neutral lipid was analyzed by GCMS and found that the extract contained long chains of hydrocarbon compounds. The hydrocarbons consisted of C18-C30 that high peaks with larger percentage area were C20-C26. The results suggested that stirring between microalgae and methanol for 30 min was needed before additional of chloroform. Moreover, the ratio of methanol must be higher than chloroform due to the higher portion of polar lipid content in the microalgae.

Prediction of body lipid change in pregnancy and lactation.

PubMed

Friggens, N C; Ingvartsen, K L; Emmans, G C

2004-04-01

A simple method to predict the genetically driven pattern of body lipid change through pregnancy and lactation in dairy cattle is proposed. The rationale and evidence for genetically driven body lipid change have their basis in evolutionary considerations and in the homeorhetic changes in lipid metabolism through the reproductive cycle. The inputs required to predict body lipid change are body lipid mass at calving (kg) and the date of conception (days in milk). Body lipid mass can be derived from body condition score and live weight. A key assumption is that there is a linear rate of change of the rate of body lipid change (dL/dt) between calving and a genetically determined time in lactation (T') at which a particular level of body lipid (L') is sought. A second assumption is that there is a linear rate of change of the rate of body lipid change (dL/dt) between T' and the next calving. The resulting model was evaluated using 2 sets of data. The first was from Holstein cows with 3 different levels of body fatness at calving. The second was from Jersey cows in first, second, and third parity. The model was found to reproduce the observed patterns of change in body lipid reserves through lactation in both data sets. The average error of prediction was low, less than the variation normally associated with the recording of condition score, and was similar for the 2 data sets. When the model was applied using the initially suggested parameter values derived from the literature the average error of prediction was 0.185 units of condition score (+/- 0.086 SD). After minor adjustments to the parameter values, the average error of prediction was 0.118 units of condition score (+/- 0.070 SD). The assumptions on which the model is based were sufficient to predict the changes in body lipid of both Holstein and Jersey cows under different nutritional conditions and parities. Thus, the model presented here shows that it is possible to predict genetically driven curves of body lipid change through lactation in a simple way that requires few parameters and inputs that can be derived in practice. It is expected that prediction of the cow's energy requirements can be substantially improved, particularly in early lactation, by incorporating a genetically driven body energy mobilization.

Structural similarities between hematoidin crystals and asteroid bodies: evidence of lipid composition.

PubMed

Brenner, D S; Drachenberg, C B; Papadimitriou, J C

2001-02-01

Hematoidin crystals (HC) are found in tissues where extravasated erythrocytes undergo degradation. Previous studies have determined that hematoidin is composed, in part, of a bilirubin-like pigment. In a previous study (Papadimitriou and Drachenberg, Ultrastruct. Pathol. 16, 413-421, 1992), we demonstrated that giant cell asteroid bodies (AB) are formed by membrane lipid bilayers. We evaluated three cases in which HC developed within splenic infarcts. The crystals were analyzed by light microscopy (LM), electron microscopy (EM), and X-ray microanalysis. A case of sarcoidosis with multiple epithelioid granulomas containing AB was studied for comparison. By LM the HC demonstrated intense, golden-color, fine threads, both intracellularly and extracellularly, in small and large clusters, and in radiating, star-shape patterns ranging in size from 2 to 200 microm. By EM the HC were composed of a core of empty clefts, consistent with dissolved lipids, suggestive of cholesterol crystals, and were surrounded by myelinoid membrane aggregates. The AB showed by LM significant morphological similarities with the intracellular HC. By EM, the AB were composed of a core of dense phospholipid bilayer tubes surrounded by a halo of myelinoid membranes. No accumulation of specific elements was found in either HC or AB by X-ray microanalysis. HC and AB show a similar star-shape morphology by both LM and EM. We postulate that this shape is due to the physicochemical properties of the accumulated lipids which originate from superfluous cell membranes created during cell fusion in the case of AB and after cellular (predominantly red cell) breakdown in the case of HC. The golden color of the HC likely results from adsorption of hydrophobic bilirubin-like pigments left over from erythrocyte breakdown into the accumulated lipids. Thus, this study shows two different (patho)physiological processes that lead to a markedly similar morphological end-product and provides further support to our proposed mechanism for AB formation.

Analysis of hepatic transcriptome demonstrates altered lipid metabolism following Lactobacillus johnsonii BS15 prevention in chickens with subclinical necrotic enteritis.

PubMed

Qing, Xiaodan; Zeng, Dong; Wang, Hesong; Ni, Xueqin; Lai, Jing; Liu, Lei; Khalique, Abdul; Pan, Kangcheng; Jing, Bo

2018-04-20

Subclinical necrotic enteritis (SNE) widely outbreaks in chickens which inflicted growth-slowing, causing enormous social and economic burdens. To better understand the molecular underpinnings of SNE on lipid metabolism and explore novel preventative strategies against SNE, we studied the regulatory mechanism of a potential probiotic, Lactobacillus johnsonii BS15 on the lipid metabolism pathways involved in chickens with SNE. One hundred eighty one-day-old chickens were randomly divided into three groups and arranged with basal diet (control and SNE group). Added with BS15 (1 × 10 6  cfu/g) or Man Rogosa Sharpe (MRS) liquid medium for 28 days. The hepatic gene expression of each group was then measured using high-throughput analysis methods (RNA-Seq). Quantitative real-time PCR (qRT-PCR) was used to detect the expression changes of the related genes. The results showed that there are eleven lipid metabolic pathways were found during the prevention of BS15 treatment in SNE chickens by RNA-Seq, including the peroxisome proliferator-activated receptor (PPAR) signaling pathway and arachidonic acid metabolism. BS15 notably facilitated the expressions of fatty acid binding protein 2 (FABP2), acyl-CoA synthetase bubblegum family member 1 (ACSBG1), perilipin 1 (PLIN1) and perilipin 2 (PLIN2), which were involved in PPAR signaling pathway of SNE chickens. Besides, suppression of phospholipase A2 group IVA (PLA2G4A) in arachidonic acid metabolism was observed in SNE chickens after BS15 prevention. The expression patterns of FABP2, ACSBG1, PLIN1, PLIN2 and PLA24G in qRT-PCR validation were consistent with RNA-Seq results. These findings indicate that SNE may affect the hepatic lipid metabolism of chickens. Meanwhile, BS15 pretreatment may provide a prospective natural prophylaxis strategy against SNE through improving the PPAR signaling pathway and arachidonic acid metabolism.

Insertion and self-diffusion of a monotopic protein, the Aquifex aeolicus sulfide quinone reductase, in supported lipid bilayers.

PubMed

Harb, Frédéric; Prunetti, Laurence; Giudici-Orticoni, Marie-Thérèse; Guiral, Marianne; Tinland, Bernard

2015-10-01

Monotopic proteins constitute a class of membrane proteins that bind tightly to cell membranes, but do not span them. We present a FRAPP (Fluorescence Recovery After Patterned Photobleaching) study of the dynamics of a bacterial monotopic protein, SQR (sulfide quinone oxidoreductase) from the thermophilic bacteria Aquifex aeolicus, inserted into two different types of lipid bilayers (EggPC: L-α-phosphatidylcholine (Egg, Chicken) and DMPC: 1,2-dimyristoyl-sn-glycero-3-phosphocholine) supported on two different types of support (mica or glass). It sheds light on the behavior of a monotopic protein inside the bilayer. The insertion of SQR is more efficient when the bilayer is in the fluid phase than in the gel phase. We observed diffusion of the protein, with no immobile fraction, and deduced from the diffusion coefficient measurements that the resulting inserted object is the same whatever the incubation conditions, i.e. homogeneous in terms of oligomerization state. As expected, the diffusion coefficient of the SQR is smaller in the gel phase than in the fluid phase. In the supported lipid bilayer, the diffusion coefficient of the SQR is smaller than the diffusion coefficient of phospholipids in both gel and fluid phase. SQR shows a diffusion behavior different from the transmembrane protein α-hemolysin, and consistent with its monotopic character. Preliminary experiments in the presence of the substrate of SQR, DecylUbiquinone, an analogue of quinone, component of transmembrane electrons transport systems of eukaryotic and prokaryotic organisms, have been carried out. Finally, we studied the behavior of SQR, in terms of insertion and diffusion, in bilayers formed with lipids from Aquifex aeolicus. All the conclusions that we have found in the biomimetic systems applied to the biological system.

Internalization and sorting of a fluorescent analogue of glucosylceramide to the Golgi apparatus of human skin fibroblasts: utilization of endocytic and nonendocytic transport mechanisms

PubMed Central

1994-01-01

We examined the uptake and intracellular transport of the fluorescent glucosylceramide analogue N-[5-(5,7-dimethyl BODIPYTM)-1-pentanoyl]- glucosyl sphingosine (C5-DMB-GlcCer) in human skin fibroblasts, and we compared its behavior to that of the corresponding fluorescent analogues of sphingomyelin, galactosylceramide, and lactosylceramide. All four fluorescent analogues were readily transferred from defatted BSA to the plasma membrane during incubation at 4 degrees C. When cells treated with C5-DMB-GlcCer were washed, warmed to 37 degrees C, and subsequently incubated with defatted BSA to remove fluorescent lipid at the cell surface, strong fluorescence was observed at the Golgi apparatus, as well as weaker labeling at the nuclear envelope and other intracellular membranes. Similar results were obtained with C5-DMB- galactosylceramide, except that labeling of the Golgi apparatus was weaker than with C5-DMB-GlcCer. Internalization of C5-DMB-GlcCer was not inhibited by various treatments, including ATP depletion or warming to 19 degrees C, and biochemical analysis demonstrated that the lipid was not metabolized during its internalization. However, accumulation of C5-DMB-GlcCer at the Golgi apparatus was reduced when cells were treated with a nonfluorescent analogue of glucosylceramide, suggesting that accumulation of C5-DMB-GlcCer at the Golgi apparatus was a saturable process. In contrast, cells treated with C5-DMB-analogues of sphingomyelin or lactosylceramide internalized the fluorescent lipid into a punctate pattern of fluorescence during warming at 37 degrees C, and this process was temperature and energy dependent. These results with C5-DMB-sphingomyelin and C5-DMB-lactosylceramide were analogous to those obtained with another fluorescent analogue of sphingomyelin in which labeling of endocytic vesicles and plasma membrane lipid recycling were documented (Koval, M., and R. E. Pagano. 1990. J. Cell Biol. 111:429-442). Incubation of perforated cells with C5-DMB- sphingomyelin resulted in prominent labeling of the nuclear envelope and other intracellular membranes, similar to the pattern observed with C5-DMB-GlcCer in intact cells. These observations are consistent with the transbilayer movement of fluorescent analogues of glucosylceramide and galactosylceramide at the plasma membrane and early endosomes of human skin fibroblasts, and suggest that both endocytic and nonendocytic pathways are used in the internalization of these lipids from the plasma membrane. PMID:8188745

Spontaneous charged lipid transfer between lipid vesicles.

PubMed

Richens, Joanna L; Tyler, Arwen I I; Barriga, Hanna M G; Bramble, Jonathan P; Law, Robert V; Brooks, Nicholas J; Seddon, John M; Ces, Oscar; O'Shea, Paul

2017-10-03

An assay to study the spontaneous charged lipid transfer between lipid vesicles is described. A donor/acceptor vesicle system is employed, where neutrally charged acceptor vesicles are fluorescently labelled with the electrostatic membrane probe Fluoresceinphosphatidylethanolamine (FPE). Upon addition of charged donor vesicles, transfer of negatively charged lipid occurs, resulting in a fluorescently detectable change in the membrane potential of the acceptor vesicles. Using this approach we have studied the transfer properties of a range of lipids, varying both the headgroup and the chain length. At the low vesicle concentrations chosen, the transfer follows a first-order process where lipid monomers are transferred presumably through the aqueous solution phase from donor to acceptor vesicle. The rate of transfer decreases with increasing chain length which is consistent with energy models previously reported for lipid monomer vesicle interactions. Our assay improves on existing methods allowing the study of a range of unmodified lipids, continuous monitoring of transfer and simplified experimental procedures.

Geochemically distinct carbon isotope distributions in Allochromatium vinosum DSM 180T grown photoautotrophically and photoheterotrophically.

PubMed

Tang, T; Mohr, W; Sattin, S R; Rogers, D R; Girguis, P R; Pearson, A

2017-03-01

Anoxygenic, photosynthetic bacteria are common at redox boundaries. They are of interest in microbial ecology and geosciences through their role in linking the carbon, sulfur, and iron cycles, yet much remains unknown about how their flexible carbon metabolism-permitting either autotrophic or heterotrophic growth-is recorded in the bulk sedimentary and lipid biomarker records. Here, we investigated patterns of carbon isotope fractionation in a model photosynthetic sulfur-oxidizing bacterium, Allochromatium vinosum DSM180 T . In one treatment, A. vinosum was grown with CO 2 as the sole carbon source, while in a second treatment, it was grown on acetate. Different intracellular isotope patterns were observed for fatty acids, phytol, individual amino acids, intact proteins, and total RNA between the two experiments. Photoautotrophic CO 2 fixation yielded typical isotopic ordering for the lipid biomarkers: δ 13 C values of phytol > n-alkyl lipids. In contrast, growth on acetate greatly suppressed intracellular isotopic heterogeneity across all molecular classes, except for a marked 13 C-depletion in phytol. This caused isotopic "inversion" in the lipids (δ 13 C values of phytol < n-alkyl lipids). The finding suggests that inverse δ 13 C patterns of n-alkanes and pristane/phytane in the geologic record may be at least in part a signal for photoheterotrophy. In both experimental scenarios, the relative isotope distributions could be predicted from an isotope flux-balance model, demonstrating that microbial carbon metabolisms can be interrogated by combining compound-specific stable isotope analysis with metabolic modeling. Isotopic differences among molecular classes may be a means of fingerprinting microbial carbon metabolism, both in the modern environment and the geologic record. © 2017 John Wiley & Sons Ltd.

Does Lipid Profile Affect Thrombin Generation During Ramadan Fasting in Patients With Cardiovascular Risks?

PubMed

Sassi, Mouna; Chakroun, Taher; Chouchène, Saoussen; Hellara, Ilhem; Boubaker, Hamdi; Grissa, Mohamed Habib; Khochtali, Ines; Hassine, Mohsen; Addad, Faouzi; Elalamy, Ismail; Nouira, Semir

2017-11-01

There is evidence that diet and variation in lipid metabolism can influence blood coagulation, but little is known about the effect of Ramadan fasting on plasmatic coagulation pattern. We investigated the effect of Ramadan fasting on thrombin generation (TG) in patients with cardiovascular disease (CVD) risks, and we aimed to assess the effect of lipid profile on TG parameters. The study was conducted in 36 adults having at least 2 CVD risks and in 30 healthy controls. Coagulation pattern was assessed by both classical clotting times and TG test. A complete lipid profile was performed simultaneously. Patients were invited 2 times: 1 week before Ramadan and during the last week of the Ramadan. The TG parameters were not different in patients with CVD risks compared to healthy controls. Fasting had no effect on plasmatic coagulation parameters and on TG profile. Individual analysis of the mean rate index (MRI) of TG revealed 3 groups: group 1 with no modification of MRI, group 2 with a significant increase in MRI (81.64 nM/min vs 136.07 nM/min; P < .001), and group 3 with a significant decrease in MRI (125.27 nM/min vs 73.18 nM/min; P = .001). Only in group 2, a significant increase was observed in total cholesterol and low-density lipoprotein cholesterol. Changes in lipid profile during Ramadan fasting did not influence the global coagulation pattern in patients with CVD risks. Whereas, a significant increase in the propagation phase of TG was associated with a significant increase in cholesterol levels, which was not found with the other TG parameters.

Lipid phenotype and heritage pattern in families with genetic hypercholesterolemia not related to LDLR, APOB, PCSK9, or APOE.

PubMed

Jarauta, Estíbaliz; Pérez-Ruiz, María Rosario; Pérez-Calahorra, Sofia; Mateo-Gallego, Rocio; Cenarro, Ana; Cofán, Montserrat; Ros, Emilio; Civeira, Fernando; Tejedor, Maria Teresa

A substantial proportion of individuals clinically diagnosed as familial hypercholesterolemia (FH) do not carry pathogenic mutations in candidate genes. Whether in them the high cholesterol trait is transmitted monogenically has not been studied. We assessed the inheritance pattern, penetrance, and expression of high low-density lipoprotein (LDL)-cholesterol (LDLc) in families with genetic hypercholesterolemia (GH) without known causative mutations (non-FH-GH). The study included probands with a clinical diagnosis of FH and their families attending 2 lipid clinics in Spain. Inclusion criteria for probands were LDLc >95th percentile, triglycerides <90th percentile, at least 1 first-degree family member with LDLc >90th percentile, >5 points in the Dutch Lipid Clinic Network criteria score, and absence of mutations in LDLR, APOB, PCSK9 or APOE. Eleven FH families with a LDLR mutation were also examined for comparison. We analyzed 49 non-FH-GH probands and 277 first-and second-degree relatives. LDLc was >90th percentile in 37.8% of blood relatives, at concentrations similar to those of probands. LDLc had a normal distribution in non-FH-GH families, in contrast with a bimodal distribution in FH families. When a dominant model was tested, family-based association tests gave much lower heritability values for total cholesterol and LDLc in non-FH-GH (0.39 and 0.32, respectively) than in FH (0.78 and 0.61, respectively). Non-FH-GH families have a milder lipid phenotype than genetically defined FH. The heritage pattern of LDLc in non-FH-GH does not fit with a monogenic disorder. Our findings support the concept that most non-FH-GHs are polygenic hypercholesterolemias. Copyright © 2016 National Lipid Association. Published by Elsevier Inc. All rights reserved.

The spatiotemporal pattern of Src activation at lipid rafts revealed by diffusion-corrected FRET imaging.

PubMed

Lu, Shaoying; Ouyang, Mingxing; Seong, Jihye; Zhang, Jin; Chien, Shu; Wang, Yingxiao

2008-07-25

Genetically encoded biosensors based on fluorescence resonance energy transfer (FRET) have been widely applied to visualize the molecular activity in live cells with high spatiotemporal resolution. However, the rapid diffusion of biosensor proteins hinders a precise reconstruction of the actual molecular activation map. Based on fluorescence recovery after photobleaching (FRAP) experiments, we have developed a finite element (FE) method to analyze, simulate, and subtract the diffusion effect of mobile biosensors. This method has been applied to analyze the mobility of Src FRET biosensors engineered to reside at different subcompartments in live cells. The results indicate that the Src biosensor located in the cytoplasm moves 4-8 folds faster (0.93+/-0.06 microm(2)/sec) than those anchored on different compartments in plasma membrane (at lipid raft: 0.11+/-0.01 microm(2)/sec and outside: 0.18+/-0.02 microm(2)/sec). The mobility of biosensor at lipid rafts is slower than that outside of lipid rafts and is dominated by two-dimensional diffusion. When this diffusion effect was subtracted from the FRET ratio images, high Src activity at lipid rafts was observed at clustered regions proximal to the cell periphery, which remained relatively stationary upon epidermal growth factor (EGF) stimulation. This result suggests that EGF induced a Src activation at lipid rafts with well-coordinated spatiotemporal patterns. Our FE-based method also provides an integrated platform of image analysis for studying molecular mobility and reconstructing the spatiotemporal activation maps of signaling molecules in live cells.

Serum lipid profile changes after successful treatment with electroconvulsive therapy in major depression: A prospective pilot trial.

PubMed

Aksay, Suna Su; Bumb, Jan Malte; Janke, Christoph; Biemann, Ronald; Borucki, Katrin; Lederbogen, Florian; Deuschle, Michael; Sartorius, Alexander; Kranaster, Laura

2016-01-01

Cholesterol is reduced in depressed patients, however, these patients have a higher risk for cardiovascular diseases. Electroconvulsive therapy (ECT) is a highly effective treatment option for specific forms of depression. Like for other non-pharmacological therapies targeting depression such as psychotherapy or sleep deprivation, there is a lack of evidence about the effects on peripheral lipid parameters. Our objective was to study the impact of ECT as a non-pharmacological treatment on the peripheral lipid pattern in depressive patients. Peripheral lipid profile composition before and after a course of ECT was analysed in 27 non-fasting inpatients at a university psychiatric hospital with DSM-IV major depressive episode. For the impact of ECT treatment on each lipid parameter a multivariate repeated measurement regression analysis was performed and computed separately for every dependent variable. Total Cholesterol and the cholesterol subtypes HDL and LDL were increased after the treatment compared to baseline. Apolipoprotein A1 was also increased after ECT, whereas apolipoprotein B was not. Indices for the prediction of cardiovascular diseases were unchanged after successful treatment by ECT. The reduction of depressive psychopathology negatively correlated with increases of HDL cholesterol and apolipoprotein A1. Subjects received several antidepressants and other psychotropic medication before and during the ECT. In our preliminary pilot study ECT as a non-pharmacological, effective treatment of depression led to distinct effects on the peripheral lipid pattern. Copyright © 2015 Elsevier B.V. All rights reserved.

Arabidopsis ribosomal proteins control vacuole trafficking and developmental programs through the regulation of lipid metabolism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Ruixi; Sun, Ruobai; Hicks, Glenn R.

The vacuole is the most prominent compartment in plant cells and is important for ion and protein storage. In our effort to search for key regulators in the plant vacuole sorting pathway, ribosomal large subunit 4 (rpl4d) was identified as a translational mutant defective in both vacuole trafficking and normal development. Polysome profiling of the rpl4d mutant showed reduction in polysome-bound mRNA compared with wild-type, but no significant change in the general mRNA distribution pattern. Ribsomal profiling data indicated that genes in the lipid metabolism pathways were translationally down-regulated in the rpl4d mutant. Live imaging studies by Nile red stainingmore » suggested that both polar and nonpolar lipid accumulation was reduced in meristem tissues of rpl4d mutants. Pharmacological evidence showed that sterol and sphingolipid biosynthetic inhibitors can phenocopy the defects of the rpl4d mutant, including an altered vacuole trafficking pattern. Genetic evidence from lipid biosynthetic mutants indicates that alteration in the metabolism of either sterol or sphingolipid biosynthesis resulted in vacuole trafficking defects, similar to the rpl4d mutant. Tissue-specific complementation with key enzymes from lipid biosynthesis pathways can partially rescue both vacuole trafficking and auxin-related developmental defects in the rpl4d mutant. These results indicate that lipid metabolism modulates auxin-mediated tissue differentiation and endomembrane trafficking pathways downstream of ribosomal protein function.« less

Arabidopsis ribosomal proteins control vacuole trafficking and developmental programs through the regulation of lipid metabolism

DOE PAGES

Li, Ruixi; Sun, Ruobai; Hicks, Glenn R.; ...

2014-12-22

The vacuole is the most prominent compartment in plant cells and is important for ion and protein storage. In our effort to search for key regulators in the plant vacuole sorting pathway, ribosomal large subunit 4 (rpl4d) was identified as a translational mutant defective in both vacuole trafficking and normal development. Polysome profiling of the rpl4d mutant showed reduction in polysome-bound mRNA compared with wild-type, but no significant change in the general mRNA distribution pattern. Ribsomal profiling data indicated that genes in the lipid metabolism pathways were translationally down-regulated in the rpl4d mutant. Live imaging studies by Nile red stainingmore » suggested that both polar and nonpolar lipid accumulation was reduced in meristem tissues of rpl4d mutants. Pharmacological evidence showed that sterol and sphingolipid biosynthetic inhibitors can phenocopy the defects of the rpl4d mutant, including an altered vacuole trafficking pattern. Genetic evidence from lipid biosynthetic mutants indicates that alteration in the metabolism of either sterol or sphingolipid biosynthesis resulted in vacuole trafficking defects, similar to the rpl4d mutant. Tissue-specific complementation with key enzymes from lipid biosynthesis pathways can partially rescue both vacuole trafficking and auxin-related developmental defects in the rpl4d mutant. These results indicate that lipid metabolism modulates auxin-mediated tissue differentiation and endomembrane trafficking pathways downstream of ribosomal protein function.« less

LMSD: LIPID MAPS structure database

PubMed Central

Sud, Manish; Fahy, Eoin; Cotter, Dawn; Brown, Alex; Dennis, Edward A.; Glass, Christopher K.; Merrill, Alfred H.; Murphy, Robert C.; Raetz, Christian R. H.; Russell, David W.; Subramaniam, Shankar

2007-01-01

The LIPID MAPS Structure Database (LMSD) is a relational database encompassing structures and annotations of biologically relevant lipids. Structures of lipids in the database come from four sources: (i) LIPID MAPS Consortium's core laboratories and partners; (ii) lipids identified by LIPID MAPS experiments; (iii) computationally generated structures for appropriate lipid classes; (iv) biologically relevant lipids manually curated from LIPID BANK, LIPIDAT and other public sources. All the lipid structures in LMSD are drawn in a consistent fashion. In addition to a classification-based retrieval of lipids, users can search LMSD using either text-based or structure-based search options. The text-based search implementation supports data retrieval by any combination of these data fields: LIPID MAPS ID, systematic or common name, mass, formula, category, main class, and subclass data fields. The structure-based search, in conjunction with optional data fields, provides the capability to perform a substructure search or exact match for the structure drawn by the user. Search results, in addition to structure and annotations, also include relevant links to external databases. The LMSD is publicly available at PMID:17098933

Thermotropic phase transitions in model membranes of the outer skin layer based on ceramide 6

NASA Astrophysics Data System (ADS)

Gruzinov, A. Yu.; Kiselev, M. A.; Ermakova, E. V.; Zabelin, A. V.

2014-01-01

The lipid intercellular matrix stratum corneum of the outer skin layer is a multilayer membrane consisting of a complex mixture of different lipids: ceramides, fatty acids, cholesterol, and its derivatives. The basis of the multilayer membrane is the lipid bilayer, i.e., a two-dimensional liquid crystal. Currently, it is known that the main way of substance penetration through the skin is the lipid matrix. The complexity of the actual biological system does not allow reliable direct study of its properties; therefore, system modeling is often used. Phase transitions in the lipid system whose composition simulates the native lipid matrix are studied by the X-ray synchrotron radiation diffraction method.

Mixing, diffusion, and percolation in binary supported membranes containing mixtures of lipids and amphiphilic block copolymers.

PubMed

Gettel, Douglas L; Sanborn, Jeremy; Patel, Mira A; de Hoog, Hans-Peter; Liedberg, Bo; Nallani, Madhavan; Parikh, Atul N

2014-07-23

Substrate-mediated fusion of small polymersomes, derived from mixtures of lipids and amphiphilic block copolymers, produces hybrid, supported planar bilayers at hydrophilic surfaces, monolayers at hydrophobic surfaces, and binary monolayer/bilayer patterns at amphiphilic surfaces, directly responding to local measures of (and variations in) surface free energy. Despite the large thickness mismatch in their hydrophobic cores, the hybrid membranes do not exhibit microscopic phase separation, reflecting irreversible adsorption and limited lateral reorganization of the polymer component. With increasing fluid-phase lipid fraction, these hybrid, supported membranes undergo a fluidity transition, producing a fully percolating fluid lipid phase beyond a critical area fraction, which matches the percolation threshold for the immobile point obstacles. This then suggests that polymer-lipid hybrid membranes might be useful models for studying obstructed diffusion, such as occurs in lipid membranes containing proteins.

Protein Diffusion on Charged Membranes: A Dynamic Mean-Field Model Describes Time Evolution and Lipid Reorganization

PubMed Central

Khelashvili, George; Weinstein, Harel; Harries, Daniel

2008-01-01

As charged macromolecules adsorb and diffuse on cell membranes in a large variety of cell signaling processes, they can attract or repel oppositely charged lipids. This results in lateral membrane rearrangement and affects the dynamics of protein function. To address such processes quantitatively we introduce a dynamic mean-field scheme that allows self-consistent calculations of the equilibrium state of membrane-protein complexes after such lateral reorganization of the membrane components, and serves to probe kinetic details of the process. Applicable to membranes with heterogeneous compositions containing several types of lipids, this comprehensive method accounts for mobile salt ions and charged macromolecules in three dimensions, as well as for lateral demixing of charged and net-neutral lipids in the membrane plane. In our model, the mobility of membrane components is governed by the diffusion-like Cahn-Hilliard equation, while the local electrochemical potential is based on nonlinear Poisson-Boltzmann theory. We illustrate the method by applying it to the adsorption of the anionic polypeptide poly-Lysine on negatively charged lipid membranes composed of binary mixtures of neutral and monovalent lipids, or onto ternary mixtures of neutral, monovalent, and multivalent lipids. Consistent with previous calculations and experiments, our results show that at steady-state multivalent lipids (such as PIP2), but not monovalent lipid (such as phosphatidylserine), will segregate near the adsorbing macromolecules. To address the corresponding diffusion of the adsorbing protein in the membrane plane, we couple lipid mobility with the propagation of the adsorbing protein through a dynamic Monte Carlo scheme. We find that due to their higher mobility dictated by the electrochemical potential, multivalent lipids such as PIP2 more quickly segregate near oppositely charged proteins than do monovalent lipids, even though their diffusion constants may be similar. The segregation, in turn, slows protein diffusion, as lipids introduce an effective drag on the motion of the adsorbate. In contrast, monovalent lipids such as phosphatidylserine only weakly segregate, and the diffusions of protein and lipid remain largely uncorrelated. PMID:18065451

Oscillatory phase separation in giant lipid vesicles induced by transmembrane osmotic differentials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oglęcka, Kamila; Rangamani, Padmini; Liedberg, Bo

Giant lipid vesicles are closed compartments consisting of semi-permeable shells, which isolate femto- to pico-liter quantities of aqueous core from the bulk. Although water permeates readily across vesicular walls, passive permeation of solutes is hindered. In this study, we show that, when subject to a hypotonic bath, giant vesicles consisting of phase separating lipid mixtures undergo osmotic relaxation exhibiting damped oscillations in phase behavior, which is synchronized with swell–burst lytic cycles: in the swelled state, osmotic pressure and elevated membrane tension due to the influx of water promote domain formation. During bursting, solute leakage through transient pores relaxes the pressuremore » and tension, replacing the domain texture by a uniform one. This isothermal phase transition—resulting from a well-coordinated sequence of mechanochemical events—suggests a complex emergent behavior allowing synthetic vesicles produced from simple components, namely, water, osmolytes, and lipids to sense and regulate their micro-environment.« less

Oscillatory phase separation in giant lipid vesicles induced by transmembrane osmotic differentials

DOE PAGES

Oglęcka, Kamila; Rangamani, Padmini; Liedberg, Bo; ...

2014-10-15

Giant lipid vesicles are closed compartments consisting of semi-permeable shells, which isolate femto- to pico-liter quantities of aqueous core from the bulk. Although water permeates readily across vesicular walls, passive permeation of solutes is hindered. In this study, we show that, when subject to a hypotonic bath, giant vesicles consisting of phase separating lipid mixtures undergo osmotic relaxation exhibiting damped oscillations in phase behavior, which is synchronized with swell–burst lytic cycles: in the swelled state, osmotic pressure and elevated membrane tension due to the influx of water promote domain formation. During bursting, solute leakage through transient pores relaxes the pressuremore » and tension, replacing the domain texture by a uniform one. This isothermal phase transition—resulting from a well-coordinated sequence of mechanochemical events—suggests a complex emergent behavior allowing synthetic vesicles produced from simple components, namely, water, osmolytes, and lipids to sense and regulate their micro-environment.« less

Biophysical characterization of monofilm model systems composed of selected tear film phospholipids.

PubMed

Patterson, Matthew; Vogel, Hans J; Prenner, Elmar J

2016-02-01

The tear film protects the eye from foreign particles and pathogens, prevents excess evaporation, provides lubrication, and maintains a high quality optical surface necessary for vision. The anterior layer of tear film consists of polar and non-polar lipid layers. The polar lipids form a monolayer on the aqueous subphase, acting as surfactants for the non-polar lipid multilayer. A tear film polar lipid biomimetic consisting of dipalmitoyl phosphatidylcholine (DPPC), dipalmitoyl phosphatidylethanolamine (DPPE), palmitoyl glucosylceramide (PGC), and palmitoyl sphingomyelin (PSM) was characterized using Langmuir monolayers and Brewster angle microscopy (BAM). Lipid combinations formed very stable monolayers, especially those containing DPPC or PSM. Surface experiments and elasticity analyses revealed that PGC resulted in more condensed and rigid mixed monolayers. DPPE provided resistance to large changes in lipid ordering over a wide surface pressure range. Ternary mixtures containing DPPE and PGC with either DPPC or PSM experienced the greatest lipid ordering within the natural tear film surface pressure range suggesting that these lipids are important to maintain tear film integrity during the inter-blink period. Finally, BAM images revealed unique structures within monolayers of DPPC, DPPE, and PGC at the natural tear film surface pressure. 3D analysis of these domains suggested either the formation of multilayers or outward protrusions at surface pressures far below the point of irreversible collapse as seen on the isotherm. This entails that the polar lipids of tear film may be capable of multilayer formation or outward folding as a mechanism to prevent rupture of the tear film during a blink. Copyright © 2015 Elsevier B.V. All rights reserved.

Identification and Characterization of Major Lipid Particle Proteins of the Yeast Saccharomyces cerevisiae

PubMed Central

Athenstaedt, Karin; Zweytick, Dagmar; Jandrositz, Anita; Kohlwein, Sepp Dieter; Daum, Günther

1999-01-01

Lipid particles of the yeast Saccharomyces cerevisiae were isolated at high purity, and their proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Major lipid particle proteins were identified by mass spectrometric analysis, and the corresponding open reading frames (ORFs) were deduced. In silicio analysis revealed that all lipid particle proteins contain several hydrophobic domains but none or only few (hypothetical) transmembrane spanning regions. All lipid particle proteins identified by function so far, such as Erg1p, Erg6p, and Erg7p (ergosterol biosynthesis) and Faa1p, Faa4p, and Fat1p (fatty acid metabolism), are involved in lipid metabolism. Based on sequence homology, another group of three lipid particle proteins may be involved in lipid degradation. To examine whether lipid particle proteins of unknown function are also involved in lipid synthesis, mutants with deletions of the respective ORFs were constructed and subjected to systematic lipid analysis. Deletion of YDL193w resulted in a lethal phenotype which could not be suppressed by supplementation with ergosterol or fatty acids. Other deletion mutants were viable under standard conditions. Strains with YBR177c, YMR313c, and YKL140w deleted exhibited phospholipid and/or neutral lipid patterns that were different from the wild-type strain and thus may be further candidate ORFs involved in yeast lipid metabolism. PMID:10515935

Linking lipid architecture to bilayer structure and mechanics using self-consistent field modelling.

PubMed

Pera, H; Kleijn, J M; Leermakers, F A M

2014-02-14

To understand how lipid architecture determines the lipid bilayer structure and its mechanics, we implement a molecularly detailed model that uses the self-consistent field theory. This numerical model accurately predicts parameters such as Helfrichs mean and Gaussian bending modulus kc and k̄ and the preferred monolayer curvature J(0)(m), and also delivers structural membrane properties like the core thickness, and head group position and orientation. We studied how these mechanical parameters vary with system variations, such as lipid tail length, membrane composition, and those parameters that control the lipid tail and head group solvent quality. For the membrane composition, negatively charged phosphatidylglycerol (PG) or zwitterionic, phosphatidylcholine (PC), and -ethanolamine (PE) lipids were used. In line with experimental findings, we find that the values of kc and the area compression modulus kA are always positive. They respond similarly to parameters that affect the core thickness, but differently to parameters that affect the head group properties. We found that the trends for k̄ and J(0)(m) can be rationalised by the concept of Israelachivili's surfactant packing parameter, and that both k̄ and J(0)(m) change sign with relevant parameter changes. Although typically k̄ < 0, membranes can form stable cubic phases when the Gaussian bending modulus becomes positive, which occurs with membranes composed of PC lipids with long tails. Similarly, negative monolayer curvatures appear when a small head group such as PE is combined with long lipid tails, which hints towards the stability of inverse hexagonal phases at the cost of the bilayer topology. To prevent the destabilisation of bilayers, PG lipids can be mixed into these PC or PE lipid membranes. Progressive loading of bilayers with PG lipids lead to highly charged membranes, resulting in J(0)(m) > 0, especially at low ionic strengths. We anticipate that these changes lead to unstable membranes as these become vulnerable to pore formation or disintegration into lipid disks.

Orientating lipase molecules through surface chemical control for enhanced activity: A QCM-D and ToF-SIMS investigation.

PubMed

Joyce, Paul; Kempson, Ivan; Prestidge, Clive A

2016-06-01

Bio-active materials consisting of lipase encapsulated within porous silica particles were engineered to control the adsorption kinetics and molecular orientation of lipase, which play critical roles in the digestion kinetics of triglycerides. The adsorption kinetics of Candida antartica lipase A (CalA) was monitored using quartz crystal microbalance with dissipation (QCM-D) and controlled by altering the hydrophobicity of a silica binding support. The extent of adsorption was 2-fold greater when CalA was adsorbed onto hydrophobic silica compared to hydrophilic silica. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) fragmentation patterns, in conjunction with multivariate statistics, demonstrated enhanced exposure of the lipase's catalytic domain, specifically the histidine group responsible for activity, when CalA was adsorbed on hydrophilic silica. Consequently, lipid digestion kinetics were enhanced when CalA was loaded in hydrophilic porous silica particles, i.e., a 2-fold increase in the pseudo-first-order rate constant for digestion when compared to free lipase. In contrast, digestion kinetics were inhibited when CalA was hosted in hydrophobic porous silica, i.e., a 5-fold decrease in pseudo-first-order rate constant for digestion when compared to free lipase. These findings provide valuable insights into the mechanism of lipase action which can be exploited to develop smarter food and drug delivery systems consisting of porous lipid-based materials. Copyright © 2016 Elsevier B.V. All rights reserved.

Direct observation of the influence of cardiolipin and antibiotics on lipid II binding to MurJ

NASA Astrophysics Data System (ADS)

Bolla, Jani Reddy; Sauer, Joshua B.; Wu, Di; Mehmood, Shahid; Allison, Timothy M.; Robinson, Carol V.

2018-03-01

Translocation of lipid II across the cytoplasmic membrane is essential in peptidoglycan biogenesis. Although most steps are understood, identifying the lipid II flippase has yielded conflicting results, and the lipid II binding properties of two candidate flippases—MurJ and FtsW—remain largely unknown. Here we apply native mass spectrometry to both proteins and characterize lipid II binding. We observed lower levels of lipid II binding to FtsW compared to MurJ, consistent with MurJ having a higher affinity. Site-directed mutagenesis of MurJ suggests that mutations at A29 and D269 attenuate lipid II binding to MurJ, whereas chemical modification of A29 eliminates binding. The antibiotic ramoplanin dissociates lipid II from MurJ, whereas vancomycin binds to form a stable complex with MurJ:lipid II. Furthermore, we reveal cardiolipins associate with MurJ but not FtsW, and exogenous cardiolipins reduce lipid II binding to MurJ. These observations provide insights into determinants of lipid II binding to MurJ and suggest roles for endogenous lipids in regulating substrate binding.

Lipid composition of thermophilic Geobacillus sp. strain GWE1, isolated from sterilization oven.

PubMed

Shah, Siddharth P; Jansen, Susan A; Taylor, Leeandrew Jacques-Asa; Chong, Parkson Lee-Gau; Correa-Llantén, Daniela N; Blamey, Jenny M

2014-05-01

GWE1 strain is an example of anthropogenic thermophilic bacterium, recently isolated from dark crusty material from sterilization ovens by Correa-Llantén et al. (Kor. J. Microb. Biotechnol. 2013. 41(3):278-283). Thermostability is likely to arise from the adaptation of macromolecules such as proteins, lipids and nucleic acids. Complex lipid arrangement and/or type in the cell membrane are known to affect thermostability of microorganisms and efforts were made to understand the chemical nature of the polar lipids of membrane. In this work, we extracted total lipids from GWE1 cell membrane, separated them by TLC into various fractions and characterize the lipid structures of certain fractions with analytical tools such as (1)H, (13)C, (31)P and 2D NMR spectroscopy, ATR-FTIR spectroscopy and MS(n) spectrometry. We were able to identify glycerophosphoethanolamine, glycerophosphate, glycerophosphocholine, glycerophosphoglycerol and cardiolipin lipid classes and an unknown glycerophospholipid class with novel MS/MS spectra pattern. We have also noticed the presence of saturated iso-branched fatty acids with NMR spectra in individual lipid classes. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Correlations Between Anthropometry and Lipid Profile in Women With PCOS.

PubMed

Kiranmayee, Donthu; Kavya, Kothapalli; Himabindu, Yalamanchali; Sriharibabu, Manne; Madhuri, Gadi Leela Jaya; Venu, Swargam

2017-01-01

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in reproductive age women and is associated with both reproductive and metabolic abnormalities. Recent studies have demonstrated an early onset of abnormal cardiovascular risk profile in women with PCOS. Abnormal lipid profile patterns are common in women with PCOS, and these abnormalities are not uniform in all populations. Anthropometry is a simple and commonly used research tool for assessing metabolic risk in women with PCOS. Therefore, this study examined the correlations between anthropometric parameters and lipid profile in women with PCOS. The objectives of the study were (1) To study the anthropometric profile of women with PCOS, (2) To examine the lipid profile pattern of these women with PCOS and (3) To see whether there exists any correlation between these anthropometric parameters and lipid profile. This observational cross-sectional study examined anthropometry and lipid profile in 86 married women with PCOS in the age group of 18-35 years and correlated them by using Pearson's correlation coefficient. More than 80% of the women with PCOS demonstrated abnormal anthropometric parameters, and in more than 70% women, lipid abnormalities such as low levels of high-density lipoprotein (HDL) cholesterol and high levels of triglycerides and low-density lipoprotein cholesterol were observed. Significant positive correlations were seen between body mass index (BMI) and triglycerides ( P ≤ 0.001) and waist circumference (WC) and triglycerides ( P ≤ 0.029). Negative correlations were observed between BMI and HDL cholesterol ( P ≤ 0.013). This study revealed that BMI and WC are the most important anthropometric parameters correlated to dyslipidemia in the south Indian women with PCOS.

Effects of oxygen and redox oscillation on degradation of cell-associated lipids in surficial marine sediments

NASA Astrophysics Data System (ADS)

Sun, Ming-Y. i.; Aller, Robert C.; Lee, Cindy; Wakeham, Stuart G.

2002-06-01

Degradation patterns of sedimentary algal lipids were tracked with time under variable redox treatments designed to mimic conditions in organic-rich, bioturbated deposits. Uniformly 13C-labeled algae were mixed with Long Island Sound surface muddy sediments and exposed to different redox regimes, including continuously oxic and anoxic, and oscillated oxic: anoxic conditions. Concentrations of several 13C-labeled algal fatty acids (16:1, 16:0 and 18:1), phytol and an alkene were measured serially. Results showed a large difference (∼10×) in first-order degradation rate constants of cell-associated lipids between continuously oxic and anoxic conditions. Exposure to oxic conditions increased the degradation of cell-associated lipids, and degradation rate constants were positive functions (linear or nonlinear) of the fraction of time sediments were oxic. Production of two new 13C-labeled compounds (iso-15:0 fatty acid and hexadecanol) further indicated that redox conditions and oxic: anoxic oscillations strongly affect microbial degradation of algal lipids and net synthesis of bacterial biomass. Production of 13C-labeled iso-15:0 fatty acid (a bacterial biomarker) was inversely proportional to the fraction of time sediments were oxic, rapidly decreasing after 10 days of incubation under oxic and frequently oscillated conditions. Turnover of bacterial biomass was faster under continuously or occasionally oxic conditions than under continuously anoxic conditions. 13C-labeled hexadecanol, an intermediate degradation product, accumulated under anoxic conditions but not under oxic or periodically oxic conditions. The frequency of oxic: anoxic oscillation clearly alters both the rate and pathways of lipid degradation in surficial sediments. Terminal degradation efficiency and lipid products from degradation of algal material depend on specific patterns of redox fluctuations.

Nuclear magnetic resonance (NMR) study of the effect of cisplatin on the metabolic profile of MG-63 osteosarcoma cells.

PubMed

Duarte, Iola F; Lamego, Ines; Marques, Joana; Marques, M Paula M; Blaise, Benjamin J; Gil, Ana M

2010-11-05

In the present study, (1)H HRMAS NMR spectroscopy was used to assess the changes in the intracellular metabolic profile of MG-63 human osteosarcoma (OS) cells induced by the chemotherapy agent cisplatin (CDDP) at different times of exposure. Multivariate analysis was applied to the cells spectra, enabling consistent variation patterns to be detected and drug-specific metabolic effects to be identified. Statistical recoupling of variables (SRV) analysis and spectral integration enabled the most relevant spectral changes to be evaluated, revealing significant time-dependent alterations in lipids, choline-containing compounds, some amino acids, polyalcohols, and nitrogenated bases. The metabolic relevance of these compounds in the response of MG-63 cells to CDDP treatment is discussed.

The structure of people's hair.

PubMed

Yang, Fei-Chi; Zhang, Yuchen; Rheinstädter, Maikel C

2014-01-01

Hair is a filamentous biomaterial consisting mainly of proteins in particular keratin. The structure of human hair is well known: the medulla is a loosely packed, disordered region near the centre of the hair surrounded by the cortex, which contains the major part of the fibre mass, mainly consisting of keratin proteins and structural lipids. The cortex is surrounded by the cuticle, a layer of dead, overlapping cells forming a protective layer around the hair. The corresponding structures have been studied extensively using a variety of different techniques, such as light, electron and atomic force microscopes, and also X-ray diffraction. We were interested in the question how much the molecular hair structure differs from person to person, between male and female hair, hair of different appearances such as colour and waviness. We included hair from parent and child, identical and fraternal twins in the study to see if genetically similar hair would show similar structural features. The molecular structure of the hair samples was studied using high-resolution X-ray diffraction, which covers length scales from molecules up to the organization of secondary structures. Signals due to the coiled-coil phase of α-helical keratin proteins, intermediate keratin filaments in the cortex and from the lipid layers in the cell membrane complex were observed in the specimen of all individuals, with very small deviations. Despite the relatively small number of individuals (12) included in this study, some conclusions can be drawn. While the general features were observed in all individuals and the corresponding molecular structures were almost identical, additional signals were observed in some specimen and assigned to different types of lipids in the cell membrane complex. Genetics seem to play a role in this composition as identical patterns were observed in hair from father and daughter and identical twins, however, not for fraternal twins. Identification and characterization of these features is an important step towards the detection of abnormalities in the molecular structure of hair as a potential diagnostic tool for certain diseases.

Using lipidomics to reveal details of lipid accumulation in developing seeds from oilseed rape (Brassica napus L.).

PubMed

Woodfield, Helen K; Cazenave-Gassiot, Amaury; Haslam, Richard P; Guschina, Irina A; Wenk, Markus R; Harwood, John L

2018-03-01

With dwindling available agricultural land, concurrent with increased demand for oil, there is much current interest in raising oil crop productivity. We have been addressing this issue by studying the regulation of oil accumulation in oilseed rape (Brassica napus L). As part of this research we have carried out a detailed lipidomic analysis of developing seeds. The molecular species distribution in individual lipid classes revealed quite distinct patterns and showed where metabolic connections were important. As the seeds developed, the molecular species distributions changed, especially in the period of early (20days after flowering, DAF) to mid phase (27DAF) of oil accumulation. The patterns of molecular species of diacylglycerol, phosphatidylcholine and acyl-CoAs were used to predict the possible relative contributions of diacylglycerol acyltransferase (DGAT) and phospholipid:diacylglycerol acyltransferase to triacylglycerol production. Our calculations suggest that DGAT may hold a more important role in influencing the molecular composition of TAG. Enzyme selectivity had an important influence on the final molecular species patterns. Our data contribute significantly to our understanding of lipid accumulation in the world's third most important oil crop. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

The lipid composition and its alteration during the growth stage in pathogenic fungus, epidermophyton floccosum

NASA Technical Reports Server (NTRS)

Yamada, T.; Watanabe, R.; Nozawa, Y.; Ito, Y.

1984-01-01

Qualitative and quantitative changes of lipid components during the growth stages were studied in E. floccosum. The acyl group components of total lipids of Trichophyton rubrum and Microsporum cookei were also examined. The lipids of E. floccosum amounted to approximately 4% of the dry cell weight. Neutral lipids mainly consisted of triglycerides and sterols, and major polar lipids were phosphatidylcholine, phosphatidylethanolamine, and an unknown lipid X. The fatty acids in tryglycerides and phospholipids were palmitic, palmitoleic, stearic, oleic, and linoleic acids. The unknown polar lipid X which appeared between phosphatidylethanolamine and cardiolipin on thin layer chromatography plates contained no phosphorus. There was no significant change in the fatty acid components of E. floccosum and T. rubrum during the cell growth, whereas profound changes occurred in M. cookei. The sterol components of E. floccosum showed striking changes depending on the growth stage.

Association of peripheral differential leukocyte counts with dyslipidemia risk in Chinese patients with hypertension: insight from the China Stroke Primary Prevention Trial.

PubMed

Liu, Yanhong; Kong, Xiangyi; Wang, Wen; Fan, Fangfang; Zhang, Yan; Zhao, Min; Wang, Yi; Wang, Yupeng; Wang, Yu; Qin, Xianhui; Tang, Genfu; Wang, Binyan; Xu, Xiping; Hou, Fan Fan; Gao, Wei; Sun, Ningling; Li, Jianping; Venners, Scott A; Jiang, Shanqun; Huo, Yong

2017-01-01

The aim of the present study was to examine the association between peripheral differential leukocyte counts and dyslipidemia in a Chinese hypertensive population. A total of 10,866 patients with hypertension were enrolled for a comprehensive assessment of cardiovascular risk factors using data from the China Stroke Primary Prevention Trial. Plasma lipid levels and total leukocyte, neutrophil, and lymphocyte counts were determined according to standard methods. Peripheral differential leukocyte counts were consistently and positively associated with serum total cholesterol (TC), LDL cholesterol (LDL-C), and TG levels (all P < 0.001 for trend), while inversely associated with HDL cholesterol levels (P < 0.05 for trend). In subsequent analyses where serum lipids were dichotomized (dyslipidemia/normolipidemia), we found that patients in the highest quartile of total leukocyte count (≥7.6 × 10 9 cells/l) had 1.64 times the risk of high TG [95% confidence interval (CI): 1.46, 1.85], 1.34 times the risk of high TC (95% CI: 1.20, 1.50), and 1.24 times the risk of high LDL-C (95% CI: 1.12, 1.39) compared with their counterparts in the lowest quartile of total leukocyte count. Similar patterns were also observed with neutrophils and lymphocytes. In summary, these findings indicate that elevated differential leukocyte counts are directly associated with serum lipid levels and increased odds of dyslipidemia. Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.

Live-cell imaging of phosphatidic acid dynamics in pollen tubes visualized by Spo20p-derived biosensor.

PubMed

Potocký, Martin; Pleskot, Roman; Pejchar, Přemysl; Vitale, Nicolas; Kost, Benedikt; Zárský, Viktor

2014-07-01

Although phosphatidic acid (PA) is structurally the simplest membrane phospholipid, it has been implicated in the regulation of many cellular events, including cytoskeletal dynamics, membrane trafficking and stress responses. Plant PA shows rapid turnover but the information about its spatio-temporal distribution in plant cells is missing. Here we demonstrate the use of a lipid biosensor that enables us to monitor PA dynamics in plant cells. The biosensor consists of a PA-binding domain of yeast SNARE Spo20p fused to fluorescent proteins. Live-cell imaging of PA dynamics in transiently transformed tobacco (Nicotiana tabacum) pollen tubes was performed using confocal laser scanning microscopy. In growing pollen tubes, PA shows distinct annulus-like fluorescence pattern in the plasma membrane behind the extreme tip. Coexpression studies with markers for other plasmalemma signaling lipids phosphatidylinositol 4,5-bisphosphate and diacylglycerol revealed limited colocalization at the shoulders of the apex. PA distribution and concentrations show distinct responses to various lipid signaling inhibitors. Fluorescence recovery after photobleaching (FRAP) analysis suggests high PA turnover in the plasma membrane. Our data show that a biosensor based on the Spo20p-PA binding domain is suitable for live-cell imaging of PA also in plant cells. In tobacco pollen tubes, distinct subapical PA maximum corroborates its involvement in the regulation of endocytosis and actin dynamics. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Torque Induced on Lipid Microtubules with Optical Tweezers

NASA Astrophysics Data System (ADS)

wichean, T. Na; Charrunchon, S.; Pattanaporkratana, A.; Limtrakul, J.; Chattham, N.

2017-09-01

Chiral Phospholipids are found self-assembled into cylindrical tubules of 500 nm in diameter by helical winding of bilayer stripes under cooling in ethanol and water solution. Theoretical prediction and experimental evidence reported so far confirmed the modulated tilt direction in a helical striped pattern of the tubules. This molecular orientation morphology results in optically birefringent tubules. We investigate an individual lipid microtubule under a single optical trap of 532 nm linearly polarized laser. Spontaneous rotation of a lipid tubule induced by radiation torque was observed with only one sense of rotation caused by chirality of a lipid tubule. Rotation discontinued once the high refractive index axis of a lipid tubule aligned with a polarization axis of the laser. We further explored a lipid tubule under circularly polarized optical trap. It was found that a lipid tubule was continuously rotated confirming the tubule birefringent property. We modified the shape of optical trap by cylindrical lens obtaining an elliptical profile optical trap. A lipid tubule can be aligned along the elongated length of optical trap. We reported an investigation of competition between polarized light torque on a birefringent lipid tubule versus torque from intensity gradient of an elongated optical trap.

Methanol-Promoted Lipid Remodelling during Cooling Sustains Cryopreservation Survival of Chlamydomonas reinhardtii

PubMed Central

Yang, Duanpeng; Li, Weiqi

2016-01-01

Cryogenic treatments and cryoprotective agents (CPAs) determine the survival rate of organisms that undergo cryopreservation, but their mechanisms of operation have not yet been characterised adequately. In particular, the way in which membrane lipids respond to cryogenic treatments and CPAs is unknown. We developed comparative profiles of the changes in membrane lipids among cryogenic treatments and between the CPAs dimethyl sulfoxide (DMSO) and methanol (MeOH) for the green alga Chlamydomonas reinhardtii. We found that freezing in liquid nitrogen led to a dramatic degradation of lipids, and that thawing at warm temperature (35°C) induced lipid remodelling. DMSO did not protect membranes, but MeOH significantly attenuated lipid degradation. The presence of MeOH during cooling (from 25°C to −55°C at a rate of 1°C/min) sustained the lipid composition to the extent that membrane integrity was maintained; this phenomenon accounts for successful cryopreservation. An increase in monogalactosyldiacylglycerol and a decrease in diacylglycerol were the major changes in lipid composition associated with survival rate, but there was no transformation between these lipid classes. Phospholipase D-mediated phosphatidic acid was not involved in freezing-induced lipid metabolism in C. reinhardtii. Lipid unsaturation changed, and the patterns of change depended on the cryogenic treatment. Our results provide new insights into the cryopreservation of, and the lipid metabolism in, algae. PMID:26731741

Plasma Phosphatidylethanolamine and Triacylglycerol Fatty Acid Concentrations are Altered in Major Depressive Disorder Patients with Seasonal Pattern.

PubMed

Otoki, Yurika; Hennebelle, Marie; Levitt, Anthony J; Nakagawa, Kiyotaka; Swardfager, Walter; Taha, Ameer Y

2017-06-01

Disturbances in peripheral and brain lipid metabolism, including the omega-3 fatty acid docosahexaenoic acid (DHA), have been reported in major depressive disorder (MDD). However, these changes have yet to be confirmed in MDD with seasonal pattern (MDD-s), a subtype of recurrent MDD. The present exploratory study quantified plasma plasmalogen and diacyl-phospholipid species, and fatty acids within total phospholipids, cholesteryl esters, triacylglycerols and free fatty acids in non-medicated MDD-s participants (n = 9) during euthymia in summer or fall, and during depression in winter in order to screen for potential high sensitivity lipid biomarkers. Triacylglycerol alpha-linolenic acid concentration was significantly decreased, and myristoleic acid concentration was significantly increased, during winter depression compared to summer-fall euthymia. 1-stearyl-2-docosahexaenoyl-sn-glycero-3-phosphoethanolamine, a diacyl-phospholipid containing stearic acid and DHA, was significantly decreased in winter depression. Concentrations of cholesteryl ester oleic acid and several polyunsaturated fatty acids between summer/fall and winter increased in proportion to the increase in depressive symptoms. The observed changes in lipid metabolic pathways in winter-type MDD-s offer new promise for lipid biomarker development.

76 FR 51876 - Medical Devices; Ophthalmic Devices; Classification of the Eyelid Thermal Pulsation System

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-19

... meibomian gland dysfunction (MGD), also known as evaporative dry eye or lipid deficiency dry eye. The system... evaporative dry eye or lipid deficiency dry eye. The system consists of a component that is inserted around...

Comparative Analyses of Three Chlorella Species in Response to Light and Sugar Reveal Distinctive Lipid Accumulation Patterns in the Microalga C. sorokiniana

PubMed Central

Barnes, Austin; Noel, Eric A.; Betenbaugh, Michael J.; Oyler, George A.

2014-01-01

While photosynthetic microalgae, such as Chlorella, serve as feedstocks for nutritional oils and biofuels, heterotrophic cultivation can augment growth rates, support high cell densities, and increase triacylglycerol (TAG) lipid content. However, these species differ significantly in their photoautotrophic and heterotrophic characteristics. In this study, the phylogeny of thirty Chlorella strains was determined in order to inform bioprospecting efforts and detailed physiological assessment of three species. The growth kinetics and lipid biochemistry of C. protothecoides UTEX 411, C. vulgaris UTEX 265, and C. sorokiniana UTEX 1230 were quantified during photoautotrophy in Bold's basal medium (BBM) and heterotrophy in BBM supplemented with glucose (10 g L−1). Heterotrophic growth rates of UTEX 411, 265, and 1230 were found to be 1.5-, 3.7-, and 5-fold higher than their respective autotrophic rates. With a rapid nine-hour heterotrophic doubling time, Chlorella sorokiniana UTEX 1230 maximally accumulated 39% total lipids by dry weight during heterotrophy compared to 18% autotrophically. Furthermore, the discrete fatty acid composition of each strain was examined in order to elucidate lipid accumulation patterns under the two trophic conditions. In both modes of growth, UTEX 411 and 265 produced 18∶1 as the principal fatty acid while UTEX 1230 exhibited a 2.5-fold enrichment in 18∶2 relative to 18∶1. Although the total lipid content was highest in UTEX 411 during heterotrophy, UTEX 1230 demonstrated a two-fold increase in its heterotrophic TAG fraction at a rate of 28.9 mg L−1 d−1 to reach 22% of the biomass, corresponding to as much as 90% of its total lipids. Interestingly, UTEX 1230 growth was restricted during mixotrophy and its TAG production rate was suppressed to 18.2 mg L−1 d−1. This constraint on carbon flow raises intriguing questions about the impact of sugar and light on the metabolic regulation of microalgal lipid biosynthesis. PMID:24699196

Comparative analyses of three Chlorella species in response to light and sugar reveal distinctive lipid accumulation patterns in the Microalga C. sorokiniana.

PubMed

Rosenberg, Julian N; Kobayashi, Naoko; Barnes, Austin; Noel, Eric A; Betenbaugh, Michael J; Oyler, George A

2014-01-01

While photosynthetic microalgae, such as Chlorella, serve as feedstocks for nutritional oils and biofuels, heterotrophic cultivation can augment growth rates, support high cell densities, and increase triacylglycerol (TAG) lipid content. However, these species differ significantly in their photoautotrophic and heterotrophic characteristics. In this study, the phylogeny of thirty Chlorella strains was determined in order to inform bioprospecting efforts and detailed physiological assessment of three species. The growth kinetics and lipid biochemistry of C. protothecoides UTEX 411, C. vulgaris UTEX 265, and C. sorokiniana UTEX 1230 were quantified during photoautotrophy in Bold's basal medium (BBM) and heterotrophy in BBM supplemented with glucose (10 g L-1). Heterotrophic growth rates of UTEX 411, 265, and 1230 were found to be 1.5-, 3.7-, and 5-fold higher than their respective autotrophic rates. With a rapid nine-hour heterotrophic doubling time, Chlorella sorokiniana UTEX 1230 maximally accumulated 39% total lipids by dry weight during heterotrophy compared to 18% autotrophically. Furthermore, the discrete fatty acid composition of each strain was examined in order to elucidate lipid accumulation patterns under the two trophic conditions. In both modes of growth, UTEX 411 and 265 produced 18:1 as the principal fatty acid while UTEX 1230 exhibited a 2.5-fold enrichment in 18:2 relative to 18:1. Although the total lipid content was highest in UTEX 411 during heterotrophy, UTEX 1230 demonstrated a two-fold increase in its heterotrophic TAG fraction at a rate of 28.9 mg L(-1) d(-1) to reach 22% of the biomass, corresponding to as much as 90% of its total lipids. Interestingly, UTEX 1230 growth was restricted during mixotrophy and its TAG production rate was suppressed to 18.2 mg L-1 d-1. This constraint on carbon flow raises intriguing questions about the impact of sugar and light on the metabolic regulation of microalgal lipid biosynthesis.

Effect of low levels of lipid oxidation on the curvature, dynamics, and permeability of lipid bilayers and their interactions with cationic nanoparticles

NASA Astrophysics Data System (ADS)

Lee, Hwankyu; Malmstadt, Noah

2018-04-01

Lipid bilayers composed of saturated and unsaturated lipids, oxidized lipids, and cholesterol at concentrations of 0–18 mol% oxidized lipid were simulated, showing that the presence of oxidized lipid increases bilayer disorder, curvature, and lateral dynamics at low oxidized-lipid concentrations of 18 mol% or less. The aldehyde terminal of a shortened oxidized-lipid tail tends to interact with water and thus bends toward the bilayer-water interface, in agreement with previous experiments and simulations. In particular, water molecules pass through the oxidized bilayer without pore formation, implying passive permeability. A single nanoparticle, which consists of 300 polystyrene (PS) chains with cationic terminals, added to this bilayer simulation induces negative bilayer curvature and inserts to the bilayer, regardless of the oxidized-lipid concentration. Hydrophobic monomers and cationic terminals of the PS particle interact respectively with lipid tails and headgroups, leading to the wrapping of either lipid monolayer or bilayer along the particle surface. These results indicate that lipid oxidation increases membrane curvature and permeability even at such a low concentration of oxidized lipid, which supports the experimental observations regarding the passive permeability of oxidized bilayer, and also that oxidized lipids of low concentration do not significantly influence the insertion of a cationic PS particle to the bilayer.

Some Lipid Droplets Are More Equal Than Others: Different Metabolic Lipid Droplet Pools in Hepatic Stellate Cells.

PubMed

Molenaar, Martijn R; Vaandrager, Arie B; Helms, J Bernd

2017-01-01

Hepatic stellate cells (HSCs) are professional lipid-storing cells and are unique in their property to store most of the retinol (vitamin A) as retinyl esters in large-sized lipid droplets. Hepatic stellate cell activation is a critical step in the development of chronic liver disease, as activated HSCs cause fibrosis. During activation, HSCs lose their lipid droplets containing triacylglycerols, cholesteryl esters, and retinyl esters. Lipidomic analysis revealed that the dynamics of disappearance of these different classes of neutral lipids are, however, very different from each other. Although retinyl esters steadily decrease during HSC activation, triacylglycerols have multiple pools one of which becomes transiently enriched in polyunsaturated fatty acids before disappearing. These observations are consistent with the existence of preexisting "original" lipid droplets with relatively slow turnover and rapidly recycling lipid droplets that transiently appear during activation of HSCs. Elucidation of the molecular machinery involved in the regulation of these distinct lipid droplet pools may open new avenues for the treatment of liver fibrosis.

The proteomics of lipid droplets: structure, dynamics, and functions of the organelle conserved from bacteria to humans

PubMed Central

Yang, Li; Ding, Yunfeng; Chen, Yong; Zhang, Shuyan; Huo, Chaoxing; Wang, Yang; Yu, Jinhai; Zhang, Peng; Na, Huimin; Zhang, Huina; Ma, Yanbin; Liu, Pingsheng

2012-01-01

Lipid droplets are cellular organelles that consists of a neutral lipid core covered by a monolayer of phospholipids and many proteins. They are thought to function in the storage, transport, and metabolism of lipids, in signaling, and as a specialized microenvironment for metabolism in most types of cells from prokaryotic to eukaryotic organisms. Lipid droplets have received a lot of attention in the last 10 years as they are linked to the progression of many metabolic diseases and hold great potential for the development of neutral lipid-derived products, such as biofuels, food supplements, hormones, and medicines. Proteomic analysis of lipid droplets has yielded a comprehensive catalog of lipid droplet proteins, shedding light on the function of this organelle and providing evidence that its function is conserved from bacteria to man. This review summarizes many of the proteomic studies on lipid droplets from a wide range of organisms, providing an evolutionary perspective on this organelle. PMID:22534641

Effects of a Squalene Epoxidase Inhibitor, Terbinafine, on Ether Lipid Biosyntheses in a Thermoacidophilic Archaeon, Thermoplasma acidophilum

PubMed Central

Kon, Takahide; Nemoto, Naoki; Oshima, Tairo; Yamagishi, Akihiko

2002-01-01

The archaeal plasma membrane consists mainly of diether lipids and tetraether lipids instead of the usual ester lipids found in other organisms. Although a molecule of tetraether lipid is thought to be synthesized from two molecules of diether lipids, there is no direct information about the biosynthetic pathway(s) or intermediates of tetraether lipid biosynthesis. In this study, we examined the effects of the fungal squalene epoxidase inhibitor terbinafine on the growth and ether lipid biosyntheses in the thermoacidophilic archaeon Thermoplasma acidophilum. Terbinafine was found to inhibit the growth of T. acidophilum in a concentration-dependent manner. When growing T. acidophilum cells were pulse-labeled with [2-14C]mevalonic acid in the presence of terbinafine, incorporation of radioactivity into the tetraether lipid fraction was strongly suppressed, while accumulation of radioactivity was noted at the position corresponding to diether lipids, depending on the concentration of terbinafine. After the cells were washed with fresh medium and incubated further without the radiolabeled substrate and the inhibitor, the accumulated radioactivity in the diether lipid fraction decreased quickly while that in the tetraether lipids increased simultaneously, without significant changes in the total radioactivity of ether lipids. These results strongly suggest that terbinafine inhibits the biosynthesis of tetraether lipids from a diether-type precursor lipid(s). The terbinafine treatment will be a tool for dissecting tetraether lipid biosynthesis in T. acidophilum. PMID:11844769

Quantitative estimates of dietary intake with special emphasis on snacking pattern and nutritional status of free living adults in urban slums of Delhi: impact of nutrition transition

PubMed Central

Singh, Archna; Gupta, Vidhu; Ghosh, Arpita; Lock, Karen; Ghosh-Jerath, Suparna

2016-01-01

Background The nutritional landscape of India is experiencing the fallout of urbanization and globalization. The changes are manifest in dietary patterns as well as health outcomes. The study aimed at assessing household dietary intake pattern with special emphasis on snacking pattern, anthropometric and lipid profiles in low socio-economic status households in an urban slum of Delhi. Methods Community based cross-sectional study in 260 households of a purposively selected urban slum in North-East district of Delhi, India. Family dietary surveys including consumption pattern of commercial food products rich in Partially Hydrogenated Vegetable Oils (PHVOs), 24 h dietary recall and assessment of dietary diversity using Household Diet Diversity Scores (HDDS) were done. Assessment of nutritional status using anthropometric and lipid profile on a subsample (n =130) were also conducted. Results Median energy and fat intake were adequate. Micronutrient intake was found to be inadequate for vitamin A, riboflavin, calcium and folate. PHVO usage was low (<20 % households). Milk (39 %), green leafy vegetables (25 %) and fruits (25 %) intake were below recommendations. Mean HDDS was 7.87. Prevalence of overweight/obesity was high (66.7 %). Lipid profile showed mean HDL-C levels lower than recommendations for females. Conclusion Community based awareness programs for prevention of non-communicable diseases should incorporate healthy diet and lifestyle practices with emphasis on quantity and quality of nutrient intake. This must be considered as an integral part of chronic disease prevention strategy for underprivileged communities in urban India. PMID:26918196

Quantitative estimates of dietary intake with special emphasis on snacking pattern and nutritional status of free living adults in urban slums of Delhi: impact of nutrition transition.

PubMed

Singh, Archna; Gupta, Vidhu; Ghosh, Arpita; Lock, Karen; Ghosh-Jerath, Suparna

2015-10-14

The nutritional landscape of India is experiencing the fallout of urbanization and globalization. The changes are manifest in dietary patterns as well as health outcomes. The study aimed at assessing household dietary intake pattern with special emphasis on snacking pattern, anthropometric and lipid profiles in low socio-economic status households in an urban slum of Delhi. Community based cross-sectional study in 260 households of a purposively selected urban slum in North-East district of Delhi, India. Family dietary surveys including consumption pattern of commercial food products rich in Partially Hydrogenated Vegetable Oils (PHVOs), 24 h dietary recall and assessment of dietary diversity using Household Diet Diversity Scores (HDDS) were done. Assessment of nutritional status using anthropometric and lipid profile on a subsample ( n =130) were also conducted. Median energy and fat intake were adequate. Micronutrient intake was found to be inadequate for vitamin A, riboflavin, calcium and folate. PHVO usage was low (<20 % households). Milk (39 %), green leafy vegetables (25 %) and fruits (25 %) intake were below recommendations. Mean HDDS was 7.87. Prevalence of overweight/obesity was high (66.7 %). Lipid profile showed mean HDL-C levels lower than recommendations for females. Community based awareness programs for prevention of non-communicable diseases should incorporate healthy diet and lifestyle practices with emphasis on quantity and quality of nutrient intake. This must be considered as an integral part of chronic disease prevention strategy for underprivileged communities in urban India.

Geometric analysis of nutrient balancing in the mealworm beetle, Tenebrio molitor L. (Coleoptera: Tenebrionidae).

PubMed

Rho, Myung Suk; Lee, Kwang Pum

2014-12-01

Geometric analysis of the nutritional regulatory responses was performed on an omnivorous mealworm beetle, Tenebrio molitor L. (Coleoptera: Tenebrionidae) to test whether this beetle had the capacity to balance the intake of protein and carbohydrate. We also identified the pattern of ingestive trade-off employed when the insect was forced to balance the costs of over- and under-ingesting macronutrients. When allowed to mix their diet from two nutritionally imbalanced but complementary foods (protein-biased food: p35:c7 or p28:c5.6; carbohydrate-biased food: p7:c35 or p5.6:c28), beetles of both sexes actively regulated their intake of protein and carbohydrate to a ratio of 1:1. When confined to one of seven nutritionally imbalanced foods (p0:c42, p7:c35, p14:c28, p21:c21, p28:c14, p35:c7 or p42:c0), beetles over-ingested the excessive nutrient from these foods to such an extent that all the points of protein-carbohydrate intake aligned linearly in the nutrient space, a pattern that is characteristic of generalist feeders and omnivores. Under the restricted feeding conditions, males ate more nutrients but were less efficient at retaining their body lipids than females. Body lipid content was higher on carbohydrate-rich foods and was positively correlated with starvation resistance. Our results are consistent with the prediction based on the nutritional heterogeneity hypothesis, which links the nutritional regulatory responses of insects to their diet breadth and feeding ecology. Copyright © 2014. Published by Elsevier Ltd.

Molecular modeling of proteinlike inclusions in lipid bilayers: lipid-mediated interactions.

PubMed

Kik, Richard A; Leermakers, Frans A M; Kleijn, J Mieke

2010-02-01

We investigated the insertion of transmembrane structures in a lipid bilayer and their interactions using self-consistent field theory. The lipids are coarse-grained on a united-atom level and consist of a phosphatidylcholinelike headgroup and two hydrophobic tails. The inclusions, acting as simple models for proteins that span biological membranes, are rigid rods (radius R ) with a hydrophobic surface and hydrophilic end caps. The insertion free energy Omega of an individual rod is strongly regulated by the affinity between its hydrophobic surface and the lipid tails. This affinity also controls the best match of the hydrophobic length of the rod with that of the bilayer. The line tension tau(=Omega/2piR) is practically independent of R . The perturbations in the bilayer as a function of distance from the inclusion, have the shape of a damped oscillation. The wavelength and decay length are related to the elastic properties of the bilayer and do not depend on R . These results are used to analyze how the lipid matrix affects the interaction between transmembrane objects, for computational reasons considering the limit of R-->infinity . Contributions on different length scales can be distinguished: (i) a long-range elastic interaction, which is an exponentially decaying oscillation; (ii) an exponentially decaying repulsion on an intermediate length scale, resulting from the loss of conformational entropy of the lipid tails; and (iii) a short-range interaction due to the finite compressibility of the lipid tails, which manifests either as a depletion attraction if there is no affinity between the tails and the inclusions' surface or, otherwise, as an oscillatory structural force.

Changes in Plasma Lipids during Exposure to Total Sleep Deprivation.

PubMed

Chua, Eric Chern-Pin; Shui, Guanghou; Cazenave-Gassiot, Amaury; Wenk, Markus R; Gooley, Joshua J

2015-11-01

The effects of sleep loss on plasma lipids, which play an important role in energy homeostasis and signaling, have not been systematically examined. Our aim was to identify lipid species in plasma that increase or decrease reliably during exposure to total sleep deprivation. Twenty individuals underwent sleep deprivation in a laboratory setting. Blood was drawn every 4 h and mass spectrometry techniques were used to analyze concentrations of 263 lipid species in plasma, including glycerolipids, glycerophospholipids, sphingolipids, and sterols. Chronobiology and Sleep Laboratory, Duke-NUS Graduate Medical School. Healthy ethnic-Chinese males aged 21-28 y (n = 20). Subjects were kept awake for 40 consecutive hours. Each metabolite time series was modeled as a sum of sinusoidal (circadian) and linear components, and we assessed whether the slope of the linear component differed from zero. More than a third of all individually analyzed lipid profiles exhibited a circadian rhythm and/or a linear change in concentration during sleep deprivation. Twenty-five lipid species showed a linear and predominantly unidirectional trend in concentration levels that was consistent across participants. Choline plasmalogen levels decreased, whereas several phosphatidylcholine (PC) species and triacylglycerides (TAG) carrying polyunsaturated fatty acids increased. The decrease in choline plasmalogen levels during sleep deprivation is consistent with prior work demonstrating that these lipids are susceptible to degradation by oxidative stress. The increase in phosphatidylcholines and triacylglycerides suggests that sleep loss might modulate lipid metabolism, which has potential implications for metabolic health in individuals who do not achieve adequate sleep. © 2015 Associated Professional Sleep Societies, LLC.

LIPID11: A Modular Framework for Lipid Simulations using Amber

PubMed Central

Skjevik, Åge A.; Madej, Benjamin D.; Walker, Ross C.; eigen, Knut T

2013-01-01

Accurate simulation of complex lipid bilayers has long been a goal in condensed phase molecular dynamics (MD). Structure and function of membrane-bound proteins are highly dependent on the lipid bilayer environment and are challenging to study through experimental methods. Within Amber, there has been limited focus on lipid simulations, although some success has been seen with the use of the General Amber Force Field (GAFF). However, to date there are no dedicated Amber lipid force fields. In this paper we describe a new charge derivation strategy for lipids consistent with the Amber RESP approach, and a new atom and residue naming and type convention. In the first instance, we have combined this approach with GAFF parameters. The result is LIPID11, a flexible, modular framework for the simulation of lipids that is fully compatible with the existing Amber force fields. The charge derivation procedure, capping strategy and nomenclature for LIPID11, along with preliminary simulation results and a discussion of the planned long-term parameter development are presented here. Our findings suggest that Lipid11 is a modular framework feasible for phospholipids and a flexible starting point for the development of a comprehensive, Amber-compatible lipid force field. PMID:22916730

Lipid domains in zwitterionic-anionic lipid mixtures induced by combined effect of monovalent and divalent ions

NASA Astrophysics Data System (ADS)

Xu, Hongcheng; Ganesan, Sai; Matysiak, Silvina

Lipid domain formation is an important process for many cellular processes. In experiment, the effects of Ba2+, Sr2+, Ca2+ and Mg2+ in inducing lateral phase separation in the binary phosphatidylcholine-phosphatidylserine (PC-PS) bilayer are quite different, of which the molecular mechanism remains to be understood. We have explored the effect of monovalent (MI) and divalent (MII) cationic radii on lipid domain formation in mixed zwitterionic-anionic lipid bilayers. We propose a mechanism for the formation of divalent-cation-induced lipid domains based on MD simulations with our Water-Explicit Polarizable MEMbrane (WEPMEM) coarse-grained model, which uses PC as the model for zwitterionic and PS for anionic lipids. Lipid aggregation only occurs with limited range of monovalent and divalent ion sizes in agreement with experimental observations. More ordering and closer packing of the lipids are noted within the domains, which correlate with bilayer thickness, curvature and lipid asymmetry. The results of the simulations reveal that the lipid domain consists of MII-mediated anionic lipid dimer/trimer complexes bridged by monovalent ions MI and provide a stereochemical insight in understanding the experimentally observed calcium-induced phase separation.

Characterization of the lateral distribution of fluorescent lipid in binary-constituent lipid monolayers by principal component analysis.

PubMed

Sugár, István P; Zhai, Xiuhong; Boldyrev, Ivan A; Molotkovsky, Julian G; Brockman, Howard L; Brown, Rhoderick E

2010-01-01

Lipid lateral organization in binary-constituent monolayers consisting of fluorescent and nonfluorescent lipids has been investigated by acquiring multiple emission spectra during measurement of each force-area isotherm. The emission spectra reflect BODIPY-labeled lipid surface concentration and lateral mixing with different nonfluorescent lipid species. Using principal component analysis (PCA) each spectrum could be approximated as the linear combination of only two principal vectors. One point on a plane could be associated with each spectrum, where the coordinates of the point are the coefficients of the linear combination. Points belonging to the same lipid constituents and experimental conditions form a curve on the plane, where each point belongs to a different mole fraction. The location and shape of the curve reflects the lateral organization of the fluorescent lipid mixed with a specific nonfluorescent lipid. The method provides massive data compression that preserves and emphasizes key information pertaining to lipid distribution in different lipid monolayer phases. Collectively, the capacity of PCA for handling large spectral data sets, the nanoscale resolution afforded by the fluorescence signal, and the inherent versatility of monolayers for characterization of lipid lateral interactions enable significantly enhanced resolution of lipid lateral organizational changes induced by different lipid compositions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeo, Jingjie; Cheng, Yuan; Li, Weifeng

A novel method of atomistic modelling and characterization of both pure ceramide and mixed lipid bilayers is being developed, using only the General Amber ForceField. Lipid bilayers modelled as pure ceramides adopt hexagonal packing after equilibration, and the area per lipid and bilayer thickness are consistent with previously reported theoretical results. Mixed lipid bilayers are modelled as a combination of ceramides, cholesterol, and free fatty acids. This model is shown to be stable after equilibration. Green tea extract, also known as epigallocatechin-3-gallate, is introduced as a spherical cluster on the surface of the mixed lipid bilayer. It is demonstrated thatmore » the cluster is able to bind to the bilayers as a cluster without diffusing into the surrounding water.« less

Starch and lipid accumulation in eight strains of six Chlorella species under comparatively high light intensity and aeration culture conditions.

PubMed

Takeshita, Tsuyoshi; Ota, Shuhei; Yamazaki, Tomokazu; Hirata, Aiko; Zachleder, Vilém; Kawano, Shigeyuki

2014-04-01

The microalgae family Chlorella species are known to accumulate starch and lipids. Although nitrogen or phosphorous deficiencies promote starch and lipids formation in many microalgae, these deficiencies also limit their growth and productivity. Therefore, the Chlorellaceae strains were attempted to increase starch and lipids productivity under high-light-intensity conditions (600-μmol photons m(-2)s(-1)). The 12:12-h light-dark (LD) cycle conditions elicited more stable growth than the continuous light (LL) conditions, whereas the starch and lipids yields increased in LL conditions. The amount of starch and lipids per cell increased in Chlorella viscosa and Chlorella vulgaris in sulfur-deficient medium, and long-chain fatty acids with 20 or more carbon atoms accumulated in cells grown in sulfur-deficient medium. Accumulation of starch and lipids was investigated in eight strains. The accumulation was strain-dependent, and varied according to the medium and light conditions. Five of the eight Chlorella strains exhibited similar accumulation patterns. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of lipid types on physicochemical characteristics, stability and antioxidant activity of gamma-oryzanol-loaded lipid nanoparticles.

PubMed

Ruktanonchai, Uracha; Sakulkhu, Usawadee; Bejrapha, Piyawan; Opanasopit, Praneet; Bunyapraphatsara, Nuntavan; Junyaprasert, Varaporn; Puttipipatkhachorn, Satit

2009-11-01

In the present study gamma-oryzanol, an antioxidant, was incorporated into three different types of solid lipid: wax, triglycerides, a mixture of glycerides as solid lipid nanoparticles (SLN) and liquid lipid (Miglyol 812) as nanoemulsion (NE). Instability was found only from NE due to its significant increase in particle size and decreased entrapment efficiency (%EE) at a storage temperature of 45 degrees C. Solid lipid type in SLN plays an important role only on %EE, but not chemical stability. A decrease in crystallinity of SLN was observed with the incorporation of gamma-oryzanol and low recrystallization index were found with two glycerides-based SLN. The in vitro release studies demonstrated that a biphasic release pattern fitted well with the Higuchi model of SLN formulations. In comparison, nearly constant release was observed in NE comprised of similar composition. Wax-based SLN demonstrated the lowest cytotoxicity. NE, wax-based SLN and a mixture of glycerides-based SLN were considered to enhance the antioxidant activity of gamma-oryzanol.

Adsorption of human tear lipocalin to human meibomian lipid films.

PubMed

Millar, Thomas J; Mudgil, Poonam; Butovich, Igor A; Palaniappan, Chendur K

2009-01-01

Tear lipocalin (Tlc) is a major lipid binding protein in tears and is thought to have an important role in stabilizing the Meibomian lipid layer by transferring lipids to it from the aqueous layer or ocular surface, or by adsorbing to it directly. These possible roles have been investigated in vitro using human Tlc. Tlc was purified from human tears by size exclusion chromatography followed by ion exchange chromatography. Three additional samples of the Tlc were prepared by lipidation, delipidation, and relipidation. The lipids extracted from the purified Tlc were analyzed by HPLC-MS followed by fragmentation. Adsorption of these different forms of Tlc to a human Meibomian lipid film spread on the surface of an artificial tear buffer in a Langmuir trough were observed by recording changes in the pressure with time (Pi-T profile) and monitoring the appearance of the film microscopically. These results were compared with similar experiments using a bovine Meibomian lipid film. The results indicated that Tlc binds slowly to a human Meibomian lipid film compared with lysozyme or lactoferrin, even at 37 degrees C. The adsorption of Tlc to a human Meibomian lipid film was very different from its adsorption to a bovine Meibomian lipid film, indicating the nature of the lipids in the film is critical to the adsorption process. Similarly, the different forms of Tlc had quite distinct adsorption patterns, as indicated both by changes in Pi-T profiles and the microscopic appearance of the films. It was concluded that human Tlc was capable of adsorbing to and penetrating into a Meibomian lipid layer, but this process is very complex and depends on both the types of lipids bound to Tlc and the lipid complement comprising the Meibomian lipid film.

Adsorption of Human Tear Lipocalin to Human Meibomian Lipid Films

PubMed Central

Millar, Thomas J.; Mudgil, Poonam; Butovich, Igor A.; Palaniappan, Chendur K.

2009-01-01

Purpose Tear lipocalin (Tlc) is a major lipid binding protein in tears and is thought to have an important role in stabilizing the Meibomian lipid layer by transferring lipids to it from the aqueous layer or ocular surface, or by adsorbing to it directly. These possible roles have been investigated in vitro using human Tlc. Methods Tlc was purified from human tears by size exclusion chromatography followed by ion exchange chromatography. Three additional samples of the Tlc were prepared by lipidation, delipidation, and relipidation. The lipids extracted from the purified Tlc were analyzed by HPLC-MS followed by fragmentation. Adsorption of these different forms of Tlc to a human Meibomian lipid film spread on the surface of an artificial tear buffer in a Langmuir trough were observed by recording changes in the pressure with time (∏-T profile) and monitoring the appearance of the film microscopically. These results were compared with similar experiments using a bovine Meibomian lipid film. Results The results indicated that Tlc binds slowly to a human Meibomian lipid film compared with lysozyme or lactoferrin, even at 37°C. The adsorption of Tlc to a human Meibomian lipid film was very different from its adsorption to a bovine Meibomian lipid film, indicating the nature of the lipids in the film is critical to the adsorption process. Similarly, the different forms of Tlc had quite distinct adsorption patterns, as indicated both by changes in ∏-T profiles and the microscopic appearance of the films. Conclusions It was concluded that human Tlc was capable of adsorbing to and penetrating into a Meibomian lipid layer, but this process is very complex and depends on both the types of lipids bound to Tlc and the lipid complement comprising the Meibomian lipid film. PMID:18757516

Lipids in RA: What do they mean?

PubMed Central

Plutzky, Jorge; Liao, Katherine P.

2018-01-01

In rheumatoid arthritis (RA), lipid levels are dynamic and can fluctuate along with changes in inflammation. A reduction in inflammation, most commonly as a result of disease modifying anti-rheumatic drug (DMARD) therapy, is associated with increases in total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C). A similar pattern of increased lipids is observed across biologic and non-biologic disease modifying anti-rheumatic drugs (DMARDs), suggesting that the main driver of changes in lipids is inflammation rather than individual treatments. In this review, we discuss new evidence shedding light on the potential mechanism underlying changes in lipid levels observed with changes in inflammation. Measured lipid levels in the blood are a result of a balance between synthesis and catabolism or absorption. Recent human studies in active RA show that the catabolic rates of lipids are higher than expected compared to expected rates in the general population. DMARD therapy appears to allow a return to baseline lower catabolic rates, resulting in an apparent increase in lipids. Additionally, we discuss findings from the recently published randomized controlled clinical trial, Canakinumab Anti-inflammatory Thrombosis Outcome Study (CANTOS). Findings from CANTOS provide further evidence for tighter control of inflammation to reduce cardiovascular risk in RA. PMID:29464513

Simulation studies of structure and edge tension of lipid bilayer edges: effects of tail structure and force-field.

PubMed

West, Ana; Ma, Kevin; Chung, Jonathan L; Kindt, James T

2013-08-15

Molecular dynamics simulations of lipid bilayer ribbons have been performed to investigate the structures and line tensions associated with free bilayer edges. Simulations carried out for dioleoyl phosphatidylcholine with three different force-field parameter sets yielded edge line tensions of 45 ± 2 pN, over 50% greater than the most recently reported experimentally determined value for this lipid. Edge tensions obtained from simulations of a series of phosphatidylcholine lipid bilayer ribbons with saturated acyl tails of length 12-16 carbons and with monounsaturated acyl tails of length 14-18 carbons could be correlated with the excess area associated with forming the edge, through a two-parameter fit. Saturated-tail lipids underwent local thickening near the edge, producing denser packing that correlated with lower line tensions, while unsaturated-tail lipids showed little or no local thickening. In a dipalmitoyl phosphatidylcholine ribbon initiated in a tilted gel-phase structure, lipid headgroups tended to tilt toward the nearer edge producing a herringbone pattern, an accommodation that may account for the reported edge-induced stabilization of an ordered structure at temperatures near a lipid gel-fluid phase transition.

Oscillatory phase separation in giant lipid vesicles induced by transmembrane osmotic differentials

PubMed Central

Oglęcka, Kamila; Rangamani, Padmini; Liedberg, Bo; Kraut, Rachel S; Parikh, Atul N

2014-01-01

Giant lipid vesicles are closed compartments consisting of semi-permeable shells, which isolate femto- to pico-liter quantities of aqueous core from the bulk. Although water permeates readily across vesicular walls, passive permeation of solutes is hindered. In this study, we show that, when subject to a hypotonic bath, giant vesicles consisting of phase separating lipid mixtures undergo osmotic relaxation exhibiting damped oscillations in phase behavior, which is synchronized with swell–burst lytic cycles: in the swelled state, osmotic pressure and elevated membrane tension due to the influx of water promote domain formation. During bursting, solute leakage through transient pores relaxes the pressure and tension, replacing the domain texture by a uniform one. This isothermal phase transition—resulting from a well-coordinated sequence of mechanochemical events—suggests a complex emergent behavior allowing synthetic vesicles produced from simple components, namely, water, osmolytes, and lipids to sense and regulate their micro-environment. DOI: http://dx.doi.org/10.7554/eLife.03695.001 PMID:25318069

Comparison of lipids in organs of the starfish Asterias amurensis associated with different treatments

NASA Astrophysics Data System (ADS)

Wang, Qi; Ikegame, Keita; Takahashi, Koretaro; Xue, Changhu; Zhang, Weinong; Wang, Hongxun; Hou, Wenfu; Wang, Yuming

2013-09-01

Lipids were extracted from organs of the starfish Asterias amurensis associated with different treatments (raw-control, boiling and heating), and then analyzed for lipid content, lipid oxidation index, lipid classes and fatty acid composition. Results showed that boiling softened the hard starfish shells, thus facilitating the collection of starfish organs. As compared with raw organs, the boiled organs had lower water content and higher lipid content, possibly due to the loss of water-holding capacity caused by protein denaturation. Both boiling and heating increased the peroxide value (PV), thiobarbituric acid (TBA) value and carbon value (CV) of lipids. Despite slight increases in the content of complex lipids, associated lipid composition had no substantial variations upon boiling and heating. For simple lipids, the content of 1, 2-diglyceride decreased in boiled and heated organs, with free fatty acids observed on thin layer chromatography (TLC). However, neither boiling nor heating significantly changed the fatty acid compositions of simple or complex lipids in starfish organs, suggesting that these two treatments had no significant effects on complex lipids in starfish organs. Together, our results indicated that boiling of starfish soon after capture facilitated the handling and extraction of useful complex lipids consisting of abundant glucosylceramide and eicosapentaenoic acid (EPA)-bounded phospholipids.

Polarizable atomic multipole-based force field for DOPC and POPE membrane lipids

NASA Astrophysics Data System (ADS)

Chu, Huiying; Peng, Xiangda; Li, Yan; Zhang, Yuebin; Min, Hanyi; Li, Guohui

2018-04-01

A polarizable atomic multipole-based force field for the membrane bilayer models 1,2-dioleoyl-phosphocholine (DOPC) and 1-palmitoyl-2-oleoyl-phosphatidylethanolamine (POPE) has been developed. The force field adopts the same framework as the Atomic Multipole Optimized Energetics for Biomolecular Applications (AMOEBA) model, in which the charge distribution of each atom is represented by the permanent atomic monopole, dipole and quadrupole moments. Many-body polarization including the inter- and intra-molecular polarization is modelled in a consistent manner with distributed atomic polarizabilities. The van der Waals parameters were first transferred from existing AMOEBA parameters for small organic molecules and then optimised by fitting to ab initio intermolecular interaction energies between models and a water molecule. Molecular dynamics simulations of the two aqueous DOPC and POPE membrane bilayer systems, consisting of 72 model molecules, were then carried out to validate the force field parameters. Membrane width, area per lipid, volume per lipid, deuterium order parameters, electron density profile, etc. were consistent with experimental values.

Light-patterning of synthetic tissues with single droplet resolution.

PubMed

Booth, Michael J; Restrepo Schild, Vanessa; Box, Stuart J; Bayley, Hagan

2017-08-24

Synthetic tissues can be generated by forming networks of aqueous droplets in lipid-containing oil. Each droplet contains a cell-free expression system and is connected to its neighbor through a lipid bilayer. In the present work, we have demonstrated precise external control of such networks by activating protein expression within single droplets, by using light-activated DNA to encode either a fluorescent or a pore-forming protein. By controlling the extent of activation, synthetic tissues were generated with graded levels of protein expression in patterns of single droplets. Further, we have demonstrated reversible activation within individual compartments in synthetic tissues by turning a fluorescent protein on-and-off. This is the first example of the high-resolution patterning of droplet networks, following their formation. Single-droplet control will be essential to power subsets of compartments within synthetic tissues or to stimulate subsets of cells when synthetic tissues are interfaced with living tissues.

Inducing morphological changes in lipid bilayer membranes with microfabricated substrates

NASA Astrophysics Data System (ADS)

Liu, Fangjie; Collins, Liam F.; Ashkar, Rana; Heberle, Frederick A.; Srijanto, Bernadeta R.; Collier, C. Patrick

2016-11-01

Lateral organization of lipids and proteins into distinct domains and anchoring to a cytoskeleton are two important strategies employed by biological membranes to carry out many cellular functions. However, these interactions are difficult to emulate with model systems. Here we use the physical architecture of substrates consisting of arrays of micropillars to systematically control the behavior of supported lipid bilayers - an important step in engineering model lipid membrane systems with well-defined functionalities. Competition between attractive interactions of supported lipid bilayers with the underlying substrate versus the energy cost associated with membrane bending at pillar edges can be systematically investigated as functions of pillar height and pitch, chemical functionalization of the microstructured substrate, and the type of unilamellar vesicles used for assembling the supported bilayer. Confocal fluorescent imaging and AFM measurements highlight correlations that exist between topological and mechanical properties of lipid bilayers and lateral lipid mobility in these confined environments. This study provides a baseline for future investigations into lipid domain reorganization on structured solid surfaces and scaffolds for cell growth.

Role of Transbilayer Distribution of Lipid Molecules on the Structure and Protein-Lipid Interaction of an Amyloidogenic Protein on the Membrane Surface

NASA Astrophysics Data System (ADS)

Cheng, Kwan; Cheng, Sara

We used molecular dynamics simulations to examine the effects of transbilayer distribution of lipid molecules, particularly anionic lipids with negatively charged headgroups, on the structure and binding kinetics of an amyloidogenic protein on the membrane surface and subsequent protein-induced structural disruption of the membrane. Our systems consisted of a model beta-sheet rich dimeric protein absorbed on asymmetric bilayers with neutral and anionic lipids and symmetric bilayers with neutral lipids. We observed larger folding, domain aggregation, and tilt angle of the absorbed protein on the asymmetric bilayer surfaces. We also detected more focused bilayer thinning in the asymmetric bilayer due to weak lipid-protein interactions. Our results support the mechanism that the higher lipid packing in the protein-contacting lipid leaflet promotes stronger protein-protein but weaker protein-lipid interactions of an amyloidogenic protein on the membrane surface. We speculate that the observed surface-induced structural and protein-lipid interaction of our model amyloidogenic protein may play a role in the early membrane-associated amyloid cascade pathway that leads to membrane structural damage of neurons in Alzheimer's disease. NSF ACI-1531594.

Metabolic management in overweight subjects with naive impaired fasting glycaemia by means of a highly standardized extract from Cynara scolymus: a double-blind, placebo-controlled, randomized clinical trial.

PubMed

Rondanelli, Mariangela; Opizzi, Annalisa; Faliva, Milena; Sala, Patrizio; Perna, Simone; Riva, Antonella; Morazzoni, Paolo; Bombardelli, Ezio; Giacosa, Attilio

2014-01-01

The aim of this study is to evaluate the efficacy of a dietary supplementation with an extract from Cynara scolymus (Cs) on the glucose pattern in a group of patients with naïve impaired fasting glycaemia (IFG). A randomized, double-blind, placebo-controlled trial has been performed in 55 overweight subjects with IFG (fasting blood glucose [FBG]: 6.11 ± 0.56 mmol/l). These subjects were randomly assigned to supplement their diet with either an extract from Cs (600 mg/d) (26 subjects) or placebo (29 matched subjects) for 8 weeks. The decrease of FBG was the primary endpoint. The assessment of Homeostatic Metabolic Assessment (HOMA), glycosylated haemoglobin, A1c-Derived Average Glucose (ADAG), lipidic pattern and anthropometric parameters were the secondary endpoints. The within groups and percent changes from baseline were analyzed by the signed rank test. The comparison between groups was performed by Wilcoxon's two sample test. The supplemented group had significant decreases of: FBG (-9.6%), HOMA (-11.7%), glycosylated haemoglobin (-2.3%), ADAG (-3.1%) and lipidic pattern. The placebo group did not show any significant difference. Compared with the placebo, the supplemented group showed a significant difference in FBG, HOMA and lipidic pattern. These data demonstrate the efficacy of Cs extract on the reduction of glycometabolic parameters in overweight subjects with IFG. Copyright © 2013 John Wiley & Sons, Ltd.

Opportunities and challenges for the use of molecular proxies in environmental reconstructions

NASA Astrophysics Data System (ADS)

Jansen, Boris

2017-04-01

The last decades have seen a dramatic increase in the use of organic matter from soils and sediments as molecular proxy for reconstructing past dynamics of vegetation and climate. Applications range from the use of changes in preserved leaf wax lipid patterns or d13C signatures of organic matter to reconstruct shifts in vegetation composition, to the use of changes in d2H patterns as a past humidity / precipitation proxy. Particularly exciting in this respect are recent developments with respect to combining various molecular proxies. For instance by compound specific d13C and d2H analysis of selected lipids that themselves are used as vegetation proxy. However, as with all scientific development, all that glitters is not gold. Together with great promise, successful application of molecular proxies to reconstruct past environmental change also comes with several important challenges. For instance, to what extent are plant lipid patterns used for vegetation reconstruction affected by genotypic plasticity of the producing plant species? How might the heterogeneity of environmental and biochemical processes on/in different plant species interfere with the successful use of d2H and d13C patterns? What is the influence of differences in input routes into a soil or sedimentary archive, e.g. aboveground vs. belowground, on the desired reconstruction? In this presentation I will discuss both the opportunities and the challenges of the use of organic matter as molecular proxy in environmental reconstructions, using several recent examples of research from our group.

Plasma lipids profile and erythrocytes system in patients with coronary heart disease

NASA Astrophysics Data System (ADS)

Malinova, Lidia I.; Simonenko, Georgy V.; Tuchin, Valery V.; Denisova, Tatyana P.

2006-08-01

Erythrocytes system study can provide a framework for detailed exploration of blood cell-cell and cell-vessel wall interactions, one of the key patterns in blood and vascular pathophysiology. Our objective was to explore erythrocytes system in patients with stable angina pectoris II f.c. (Canadian classification). The participants (N = 56, age 40 - 55 years) without obesity, glucose tolerance violations, lipid lowering drugs treating, heart failure of II and more functional classes (NYHA), coronary episode at least 6 months before study were involved in the study. Blood samples were incubated with glucose solutions of increasing concentrations (from 2.5% to 20% with 2.5% step) during 60 mm (36° C). In prepared blood smears erythrocyte's sizes were studied. Plasma total cholesterol, triglyceride and glucose levels were also measured. Received data were approximated by polynomials of high degree, with after going first and second derivations. Erythrocytes system "behavior" was studied by means of phase pattern constructing. By lipids levels all the patient were divided into five groups: 1) patients with normal lipids levels, 2) patients with borderline total cholesterol level, 3) patients with isolated hypercholesterolemia, 4) patients with isolated hypertriglyceridemia and 5) patients with combined hyperlipidemia. Erythrocytes size lowering process was of set of "stages", which characteristics differ significantly (p > 0.05) in all five groups. Their rate and acceleration characteristics allow us to detect type of lipid profile in patients. Erythrocyte system disturbing by glucose concentration increase show to be most resistant in group of patients with isolated hypercholesterolemia.

7-dehydrocholesterol efficiently supports Ret signaling in a mouse model of Smith-Opitz-Lemli syndrome

PubMed Central

Gou-Fàbregas, Myriam; Macià, Anna; Anerillas, Carlos; Vaquero, Marta; Jové, Mariona; Jain, Sanjay; Ribera, Joan; Encinas, Mario

2016-01-01

Smith-Lemli-Opitz syndrome (SLOS) is a rare disorder of cholesterol synthesis. Affected individuals exhibit growth failure, intellectual disability and a broad spectrum of developmental malformations. Among them, renal agenesis or hypoplasia, decreased innervation of the gut, and ptosis are consistent with impaired Ret signaling. Ret is a receptor tyrosine kinase that achieves full activity when recruited to lipid rafts. Mice mutant for Ret are born with no kidneys and enteric neurons, and display sympathetic nervous system defects causing ptosis. Since cholesterol is a critical component of lipid rafts, here we tested the hypothesis of whether the cause of the above malformations found in SLOS is defective Ret signaling owing to improper lipid raft composition or function. No defects consistent with decreased Ret signaling were found in newborn Dhcr7−/− mice, or in Dhcr7−/− mice lacking one copy of Ret. Although kidneys from Dhcr7−/− mice showed a mild branching defect in vitro, GDNF was able to support survival and downstream signaling of sympathetic neurons. Consistently, GFRα1 correctly partitioned to lipid rafts in brain tissue. Finally, replacement experiments demonstrated that 7-DHC efficiently supports Ret signaling in vitro. Taken together, our findings do not support a role of Ret signaling in the pathogenesis of SLOS. PMID:27334845

Pattern of Altered Lipid Profile in Patients with Subclinical and Clinical Hypothyroidism and its Correlation with Body Mass Index.

PubMed

Humerah, Sobia; Siddiqui, Arif; Khan, Humaira Fayyaz

2016-06-01

To compare the lipid profile of the subclinical and clinical hypothyroid patients and to evaluate the correlation between body mass index (BMI) and lipid profile in hypothyroidism. Cross-sectional study. Islamic International Medical College, Riphah International University, Islamabad, and Citi Laboratory, Rawalpindi, from January to December 2013. The subjects were selected through non-probability, purposive sampling. On the basis of thyroid profile, the subjects were divided into 3 groups: euthyroids (n=20), subclinical hypothyroids (n=50), and clinical hypothyroids (n=30). The blood of these subjects was then analyzed for lipid profile. Data was analyzed using SPSS version 18 statistical software. Both hypothyroid groups showed altered lipid profile which was observed to be significantly raised when compared with the euthyroid subjects. Comparison of lipid profile in euthyroid, subclinical, and clinical hypothyroid groups showed significant differences by non-parametric tests (p < 0.05). An assessment of correlation of lipid profile with the BMI was found to be significant (p < 0.01). Hypothyroidism causes alteration of lipid profile. Clinical and subclinical hypothyroid patients have altered lipid profile as compared to euthyroids. Thyroid status monitoring is very important, since it can induce changes in lipid profile. Such dyslipidemic status is significant not only for the management of thyroid disorders but also for common diseases like obesity and coronary atherosclerosis in the population.

Metabolic fuels: regulating fluxes to select mix.

PubMed

Weber, Jean-Michel

2011-01-15

Animals must regulate the fluxes of multiple fuels to support changing metabolic rates that result from variation in physiological circumstances. The aim of fuel selection strategies is to exploit the advantages of individual substrates while minimizing the impact of disadvantages. All exercising mammals share a general pattern of fuel selection: at the same %V(O(2,max)) they oxidize the same ratio of lipids to carbohydrates. However, highly aerobic species rely more on intramuscular fuels because energy supply from the circulation is constrained by trans-sarcolemmal transfer. Fuel selection is performed by recruiting different muscles, different fibers within the same muscles or different pathways within the same fibers. Electromyographic analyses show that shivering humans can modulate carbohydrate oxidation either through the selective recruitment of type II fibers within the same muscles or by regulating pathway recruitment within type I fibers. The selection patterns of shivering and exercise are different: at the same %V(O(2,max)), a muscle producing only heat (shivering) or significant movement (exercise) strikes a different balance between lipid and carbohydrate oxidation. Long-distance migrants provide an excellent model to characterize how to increase maximal substrate fluxes. High lipid fluxes are achieved through the coordinated upregulation of mobilization, transport and oxidation by activating enzymes, lipid-solubilizing proteins and membrane transporters. These endurance athletes support record lipolytic rates in adipocytes, use lipoprotein shuttles to accelerate transport and show increased capacity for lipid oxidation in muscle mitochondria. Some migrant birds use dietary omega-3 fatty acids as performance-enhancing agents to boost their ability to process lipids. These dietary fatty acids become incorporated in membrane phospholipids and bind to peroxisome proliferator-activated receptors to activate membrane proteins and modify gene expression.

Fatty acid signatures of stomach oil and adipose tissue of northern fulmars (Fulmarus glacialis) in Alaska: Implications for diet analysis of Procellariiform birds

USGS Publications Warehouse

Wang, S.W.; Iverson, S.J.; Springer, A.M.; Hatch, Shyla A.

2007-01-01

Procellariiforms are unique among seabirds in storing dietary lipids in both adipose tissue and stomach oil. Thus, both lipid sources are potentially useful for trophic studies using fatty acid (FA) signatures. However, little is known about the relationship between FA signatures in stomach oil and adipose tissue of individuals or whether these signatures provide similar information about diet and physiology. We compared the FA composition of stomach oil and adipose tissue biopsies of individual northern fulmars (N = 101) breeding at three major colonies in Alaska. Fatty acid signatures differed significantly between the two lipid sources, reflecting differences in dietary time scales, metabolic processing, or both. However, these signatures exhibited a relatively consistent relationship between individuals, such that the two lipid sources provided a similar ability to distinguish foraging differences among individuals and colonies. Our results, including the exclusive presence of dietary wax esters in stomach oil but not adipose tissue, are consistent with the notion that stomach oil FA signatures represent lipids retained from prey consumed during recent foraging and reflect little metabolic processing, whereas adipose tissue FA signatures represent a longer-term integration of dietary intake. Our study illustrates the potential for elucidating short- versus longer-term diet information in Procellariiform birds using different lipid sources. ?? 2007 Springer-Verlag.

In vitro cell injury by oxidized low density lipoprotein involves lipid hydroperoxide-induced formation of alkoxyl, lipid, and peroxyl radicals.

PubMed Central

Coffey, M D; Cole, R A; Colles, S M; Chisolm, G M

1995-01-01

Mounting evidence supports current theories linking lipoprotein oxidation to atherosclerosis. We sought the cellular biochemical mechanism by which oxidized LDL inflicts cell injury. Inhibitors of candidate pathways of cell death were used to treat human fibroblast target cells exposed to oxidized LDL.. Ebselen, which degrades lipid hydroperoxides, inhibited oxidized LDL toxicity, consistent with our recent report that 7 beta-hydroperoxycholesterol (7 beta-OOH chol) is the major cytotoxin of oxidized LDL. Intracellular chelation of metal ions inhibited, while preloading cells with iron enhanced, toxicity, Inhibition of oxidized LDL and 7 beta-OOH chol toxicity by 2-keto-4-thiolmethyl butyric acid, a putative alkoxyl radical scavenger and by vitamin E, probucol and diphenylphenylenediamine, putative scavengers of peroxyl radicals was consistent with the involvement of these radicals in the lethal sequence. Cell death was thus postulated to occur due to lipid peroxidation via a sequence involving lipid hydroperoxide-induced, iron-mediated formation of alkoxyl, lipid, and peroxyl radicals. Pathways involving other reactive oxygen species, new protein synthesis, or altered cholesterol metabolism were considered less likely, since putative inhibitors failed to lessen toxicity. Understanding the mechanism of cell injury by oxidized LDL and its toxic moiety, 7 beta-OOH chol, may indicate specific interventions in the cell injury believed to accompany vascular lesion development. PMID:7560078

A model of lipid-free Apolipoprotein A-I revealed by iterative molecular dynamics simulation

DOE PAGES

Zhang, Xing; Lei, Dongsheng; Zhang, Lei; ...

2015-03-20

Apolipoprotein A-I (apo A-I), the major protein component of high-density lipoprotein, has been proven inversely correlated to cardiovascular risk in past decades. The lipid-free state of apo A-I is the initial stage which binds to lipids forming high-density lipoprotein. Molecular models of lipid-free apo A-I have been reported by methods like X-ray crystallography and chemical cross-linking/mass spectrometry (CCL/MS). Through structural analysis we found that those current models had limited consistency with other experimental results, such as those from hydrogen exchange with mass spectrometry. Through molecular dynamics simulations, we also found those models could not reach a stable equilibrium state. Therefore,more » by integrating various experimental results, we proposed a new structural model for lipidfree apo A-I, which contains a bundled four-helix N-terminal domain (1–192) that forms a variable hydrophobic groove and a mobile short hairpin C-terminal domain (193–243). This model exhibits an equilibrium state through molecular dynamics simulation and is consistent with most of the experimental results known from CCL/MS on lysine pairs, fluorescence resonance energy transfer and hydrogen exchange. This solution-state lipid-free apo A-I model may elucidate the possible conformational transitions of apo A-I binding with lipids in high-density lipoprotein formation.« less

Associations of human retinal very long-chain polyunsaturated fatty acids with dietary lipid biomarkers

PubMed Central

Gorusupudi, Aruna; Liu, Aihua; Hageman, Gregory S.; Bernstein, Paul S.

2016-01-01

The human retina is well-known to have unique lipid profiles enriched in long-chain polyunsaturated fatty acids (LC-PUFAs) and very long-chain polyunsaturated fatty acids (VLC-PUFAs) that appear to promote normal retinal structure and function, but the influence of diet on retinal lipid profiles in health and disease remains controversial. In this study, we examined two independent cohorts of donor eyes and related their retinal lipid profiles with systemic biomarkers of lipid intake. We found that serum and red blood cell lipids, and to a lesser extent orbital fat, are indeed excellent biomarkers of retinal lipid content and n-3/n-6 ratios in both the LC-PUFA and VLC-PUFA series. Eyes from age-related macular degeneration (AMD) donors have significantly decreased levels of VLC-PUFAs and low n-3/n-6 ratios. These results are consistent with the protective role of dietary n-3 LC-PUFAs against AMD and emphasize the importance of monitoring systemic biomarkers of lipid intake when undertaking clinical trials of lipid supplements for prevention and treatment of retinal disease. PMID:26764040

Influence of cationic lipid concentration on properties of lipid-polymer hybrid nanospheres for gene delivery.

PubMed

Bose, Rajendran J C; Arai, Yoshie; Ahn, Jong Chan; Park, Hansoo; Lee, Soo-Hong

2015-01-01

Nanoparticles have been widely used for nonviral gene delivery. Recently, cationic hybrid nanoparticles consisting of two different materials were suggested as a promising delivery vehicle. In this study, nanospheres with a poly(D,L-lactic-co-glycolic acid) (PLGA) core and cationic lipid shell were prepared, and the effect of cationic lipid concentrations on the properties of lipid polymer hybrid nanocarriers investigated. Lipid-polymer hybrid nanospheres (LPHNSs) were fabricated by the emulsion-solvent evaporation method using different concentrations of cationic lipids and characterized for size, surface charge, stability, plasmid DNA-binding capacity, cytotoxicity, and transfection efficiency. All LPHNSs had narrow size distribution with positive surface charges (ζ-potential 52-60 mV), and showed excellent plasmid DNA-binding capacity. In vitro cytotoxicity measurements with HEK293T, HeLa, HaCaT, and HepG2 cells also showed that LPHNSs exhibited less cytotoxicity than conventional transfection agents, such as Lipofectamine and polyethyleneimine-PLGA. As cationic lipid concentrations increased, the particle size of LPHNSs decreased while their ζ-potential increased. In addition, the in vitro transfection efficiency of LPHNSs increased as lipid concentration increased.

Preparation and Optimization OF Palm-Based Lipid Nanoparticles Loaded with Griseofulvin.

PubMed

Huei Lim, Wen; Jean Tan, Yann; Sin Lee, Choy; Meng Er, Hui; Fung Wong, Shew

2017-01-01

Palm-based lipid nanoparticle formulation loaded with griseofulvin was prepared by solvent-free hot homogenization method. The griseofulvin loaded lipid nanoparticles were prepared via stages of optimisation, by altering the high pressure homogenisation (HPH) parameters, screening on palm-based lipids and Tween series surfactants and selection of lipid to surfactant ratios. A HPLC method has been validated for the drug loading capacity study. The optimum HPH parameter was determined to be 1500 bar with 5 cycles and among the palm-based lipid materials; Lipid C (triglycerides) was selected for the preparation of lipid nanoparticles. Tween 80 was chosen from the Tween series surfactants for its highest saturated solubility of griseofulvin at 53.1 ± 2.16 µg/mL. The optimum formulation of the griseofulvin loaded lipid nanoparticles demonstrated nano-range of particle size (179.8 nm) with intermediate distribution index (PDI) of 0.306, zeta potential of -27.9 mV and drug loading of 0.77%. The formulation was stable upon storage for 1 month at room temperature (25 ° C) and 45 ° C with consistent drug loading capacity.

Rapid fabrication of three-dimensional structures for dielectrophoretic sorting of lipid-containing organisms

NASA Astrophysics Data System (ADS)

Schor, Alisha R.; Buie, Cullen R.

2016-10-01

In this work, we demonstrate a microfluidic particle sorter consisting of three-dimensional, conducting microposts. Our sorter uses dielectrophoresis (DEP) to sort high- and low-lipid phenotypes of the yeast Yarrowia lipolytica. Y. lipolytica is one of the many microorganisms being explored as a hydrocarbon source for biodiesel, Omega-3 additives, and other products derived from fatty acids. A rapid, non-destructive, lipid-based sorting tool would accelerate the commercialization of these products. Our device consists of an array of 105, 25 μm wide gold microposts that span the height of a 15 μm channel. This array generates an electric field in a microfluidic device that is uniform through the channel height, but has a custom-shaped non-uniformity in the horizontal directions. This is crucial in order to achieve continuous sorting using DEP, as it ensures all cells are exposed to the same conditions throughout the channel height. By using very low currents (100 μA), we are able to electroplate these post arrays in fewer than 15 min. This is an order of magnitude improvement over previous reports of electroplated microstructures. With an applied signal of 250 MHz, 2.6 V pp in our device, we separate a heterogeneous population with a purity of 97.8% in the low-lipid stream and 71.4% in the high-lipid stream. The high-lipid stream purity can be improved by adjusting the spacing of the array. This unique protocol for the rapid fabrication of 3D microstructures has enabled the creation of a non-invasive sorting tool for genetically engineered, lipid-producing organisms. The ability to screen organisms based on lipid content will alleviate one of the major bottlenecks in commercialization of microbial biofuels.

Structure and biosynthesis of free lipid A molecules that replace lipopolysaccharide in Francisella novicida

PubMed Central

Wang, Xiaoyuan; Ribeiro, Anthony A.; Guan, Ziqiang; McGrath, Sara C.; Cotter, Robert J.; Raetz, Christian R. H.

2008-01-01

Francisella novicida U112 phospholipids, extracted without hydrolysis, consist mainly of phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, and two lipid A species, designated A1 and A2. These lipid A species, present in a ratio of 7:1, comprise 15 % of the total phospholipids, as judged by 32Pi labeling. Although lipopolysaccharide is detectable in F. novicida U112, less than 5 % of the total lipid A is covalently linked to it. A1 and A2 were analyzed by electrospray ionization and matrix-assisted laser desorption ionization mass spectrometry, gas chromatography/mass spectrometry and NMR spectroscopy. Both compounds are disaccharides of glucosamine, acylated with primary 3-hydroxystearoyl chains at positions 2, 3, and 2′, and a secondary palmitoyl residue at position 2′. Minor isobaric species and some lipid A molecules containing a 3-hydroxypalmitoyl chain in place of 3-hydroxystearate are also present. The 4′- and 3′-positions of A1 and A2 are not derivatized, and Kdo is not detectable. The 1-phosphate groups of both A1 and A2 are modified with an α-linked galactosamine residue, as shown by NMR spectroscopy and gas chromatography/mass spectrometry. An α-linked glucose moiety is attached to the 6′-position of A2. The lipid A released by mild acid hydrolysis of F. novicida lipopolysaccharide consists solely of component A1. F. novicida mutants lacking the arnT gene do not contain a galactosamine residue on their lipid A. Formation of free lipid A in F. novicida might be initiated by an unusual Kdo hydrolase present in the membranes of this organism. PMID:17128982

Separation of Membrane-Bound Compounds by Solid-Supported Bilayer Electrophoresis

PubMed Central

Daniel, Susan; Diaz, Arnaldo J.; Martinez, Kelly M.; Bench, Bennie J.; Albertorio, Fernando; Cremer, Paul S.

2008-01-01

A new method was developed to purify membrane bound species within a supported lipid bilayer (SLB) environment. SLBs consisting of phosphatidylcholine lipids and cholesterol were employed as the separation matrix. Cholesterol was used to reduce the diffusion of lipids within the bilayer and, therefore, substantially reduce mixing of the dye-conjugated lipids to be separated. These molecules were introduced into an SLB adjacent to the separations SLB and electrophoresis was employed to move these species through it. The method was powerful enough to completely resolve two isomers of Texas Red DHPE from each other. Moreover, these isomers could be separated from a BODIPY-conjugated lipid as well. Such procedures could be extended to the purification of peripheral and transmembrane proteins. PMID:17564451

Chemically induced phospholipid translocation across biological membranes.

PubMed

Gurtovenko, Andrey A; Onike, Olajide I; Anwar, Jamshed

2008-09-02

Chemical means of manipulating the distribution of lipids across biological membranes is of considerable interest for many biomedical applications as a characteristic lipid distribution is vital for numerous cellular functions. Here we employ atomic-scale molecular simulations to shed light on the ability of certain amphiphilic compounds to promote lipid translocation (flip-flops) across membranes. We show that chemically induced lipid flip-flops are most likely pore-mediated: the actual flip-flop event is a very fast process (time scales of tens of nanoseconds) once a transient water defect has been induced by the amphiphilic chemical (dimethylsulfoxide in this instance). Our findings are consistent with available experimental observations and further emphasize the importance of transient membrane defects for chemical control of lipid distribution across cell membranes.

Molecular dynamics modelling of EGCG clusters on ceramide bilayers

NASA Astrophysics Data System (ADS)

Yeo, Jingjie; Cheng, Yuan; Li, Weifeng; Zhang, Yong-Wei

2015-12-01

A novel method of atomistic modelling and characterization of both pure ceramide and mixed lipid bilayers is being developed, using only the General Amber ForceField. Lipid bilayers modelled as pure ceramides adopt hexagonal packing after equilibration, and the area per lipid and bilayer thickness are consistent with previously reported theoretical results. Mixed lipid bilayers are modelled as a combination of ceramides, cholesterol, and free fatty acids. This model is shown to be stable after equilibration. Green tea extract, also known as epigallocatechin-3-gallate, is introduced as a spherical cluster on the surface of the mixed lipid bilayer. It is demonstrated that the cluster is able to bind to the bilayers as a cluster without diffusing into the surrounding water.

Rapid evolution of cuticular hydrocarbons in a species radiation of acoustically diverse Hawaiian crickets (Gryllidae: trigonidiinae: Laupala).

PubMed

Mullen, Sean P; Mendelson, Tamra C; Schal, Coby; Shaw, Kerry L

2007-01-01

Understanding the origin and maintenance of barriers to gene exchange is a central goal of speciation research. Hawaiian swordtail crickets (genus Laupala) represent one of the most rapidly speciating animal groups yet identified. Extensive acoustic diversity, strong premating isolation, and female preference for conspecific acoustic signals in laboratory phonotaxis trials have strongly supported divergence in mate recognition as the driving force behind the explosive speciation seen in this system. However, recent work has shown that female preference for conspecific male calling song does not extend to mate choice at close range among these crickets, leading to the hypothesis that additional sexual signals are involved in mate recognition and premating isolation. Here we examine patterns of variation in cuticular lipids among several species of Laupala from Maui and the Big Island of Hawaii. Results demonstrate (1) a rapid and dramatic evolution of cuticular lipid composition among species in this genus, (2) significant differences among males and females in cuticular lipid composition, and (3) a significant reduction in the complexity of cuticular lipid profiles in species from the Big Island of Hawaii as compared to two outgroup species from Maui. These results suggest that behavioral barriers to gene exchange in Laupala may be composed of multiple mate recognition signals, a pattern common in other cricket species.

Intimal cushions and endothelial nuclear elongation around mouse aortic branches and their spatial correspondence with patterns of lipid deposition

PubMed Central

Bond, Andrew R.; Ni, Chih-Wen; Jo, Hanjoong

2010-01-01

Spatial variation in hemodynamic stresses acting on the arterial wall may explain the nonuniform distribution of atherosclerosis. In thoracic aortas of LDL receptor/apolipoprotein E double knockout mice, lesions develop preferentially around the entire circumference of intercostal branch ostia, regardless of age, with the highest prevalence occurring upstream. Additional chevron-shaped lesions occur further upstream of the ostia. This pattern differs from the age-related ones occurring in people and rabbits. In the present study, patterns of near-wall blood flow around intercostal ostia in wild-type mice were estimated from the morphology of endothelial nuclei, which were shown in vitro to elongate in response to elevated shear stress and to align with the flow, and wall structure was assessed from confocal and scanning electron microscopy. A triangular intimal cushion surrounded the upstream part of most ostia. Nuclear length-to-width ratios were lowest over this cushion and highest at the sides of branches, regardless of age. Nuclear orientations were consistent with flow diverging around the branch. The pattern of nuclear morphology differed from the age-related ones observed in rabbits. The intimal cushion and the distribution of shear stress inferred from these observations can partly account for the pattern of lesions observed in knockout mice. Nuclear elongation in nonbranch regions was approximately constant across animals of different size, demonstrating the existence of a mechanism by which endothelial cells compensate for the dependence of mean aortic wall shear stress on body mass. PMID:19933414

The Sheep Genome Illuminates Biology of the Rumen and Lipid Metabolism

PubMed Central

Talbot, Richard; Maddox, Jillian F.; Faraut, Thomas; Wu, Chunhua; Muzny, Donna M.; Li, Yuxiang; Zhang, Wenguang; Stanton, Jo-Ann; Brauning, Rudiger; Barris, Wesley C.; Hourlier, Thibaut; Aken, Bronwen L.; Searle, Stephen M.J.; Adelson, David L.; Bian, Chao; Cam, Graham R.; Chen, Yulin; Cheng, Shifeng; DeSilva, Udaya; Dixen, Karen; Dong, Yang; Fan, Guangyi; Franklin, Ian R.; Fu, Shaoyin; Guan, Rui; Highland, Margaret A.; Holder, Michael E.; Huang, Guodong; Ingham, Aaron B.; Jhangiani, Shalini N.; Kalra, Divya; Kovar, Christie L.; Lee, Sandra L.; Liu, Weiqing; Liu, Xin; Lu, Changxin; Lv, Tian; Mathew, Tittu; McWilliam, Sean; Menzies, Moira; Pan, Shengkai; Robelin, David; Servin, Bertrand; Townley, David; Wang, Wenliang; Wei, Bin; White, Stephen N.; Yang, Xinhua; Ye, Chen; Yue, Yaojing; Zeng, Peng; Zhou, Qing; Hansen, Jacob B.; Kristensen, Karsten; Gibbs, Richard A.; Flicek, Paul; Warkup, Christopher C.; Jones, Huw E.; Oddy, V. Hutton; Nicholas, Frank W.; McEwan, John C.; Kijas, James; Wang, Jun; Worley, Kim C.; Archibald, Alan L.; Cockett, Noelle; Xu, Xun; Wang, Wen; Dalrymple, Brian P.

2014-01-01

Sheep (Ovis aries) are a major source of meat, milk and fiber in the form of wool, and represent a distinct class of animals that have a specialized digestive organ, the rumen, which carries out the initial digestion of plant material. We have developed and analyzed a high quality reference sheep genome and transcriptomes from 40 different tissues. We identified highly expressed genes encoding keratin cross-linking proteins associated with rumen evolution. We also identified genes involved in lipid metabolism that had been amplified and/or had altered tissue expression patterns. This may be in response to changes in the barrier lipids of the skin, an interaction between lipid metabolism and wool synthesis, and an increased role of volatile fatty acids in ruminants, compared to non-ruminant animals. PMID:24904168

Targeting Overconsumption of Sugar-Sweetened Beverages vs. Overall Poor Diet Quality for Cardiometabolic Diseases Risk Prevention: Place Your Bets!

PubMed Central

Arsenault, Benoit J.; Lamarche, Benoît; Després, Jean-Pierre

2017-01-01

Chronic overconsumption of sugar-sweetened beverages (SSBs) is amongst the dietary factors most consistently found to be associated with obesity, type 2 diabetes (T2D) and cardiovascular disease (CVD) risk in large epidemiological studies. Intervention studies have shown that SSB overconsumption increases intra-abdominal obesity and ectopic lipid deposition in the liver, and also exacerbates cardiometabolic risk. Similar to the prevalence of obesity and T2D, national surveys of food consumption have shown that chronic overconsumption of SSBs is skyrocketing in many parts of the world, yet with marked heterogeneity across countries. SSB overconsumption is also particularly worrisome among children and adolescents. Although the relationships between SSB overconsumption and obesity, T2D, and CVD are rather consistent in epidemiological studies, it has also been shown that SSB overconsumption is part of an overall poor dietary pattern and is particularly prevalent among subgroups of the population with low socioeconomic status, thereby questioning the major focus on SSBs to target/prevent cardiometabolic diseases. Public health initiatives aimed specifically at decreasing SSB overconsumption will most likely be successful in influencing SSB consumption per se. However, comprehensive strategies targeting poor dietary patterns and aiming at improving global dietary quality are likely to have much more impact in addressing the unprecedented public health challenges that we are currently facing. PMID:28608806

Targeting Overconsumption of Sugar-Sweetened Beverages vs. Overall Poor Diet Quality for Cardiometabolic Diseases Risk Prevention: Place Your Bets!

PubMed

Arsenault, Benoit J; Lamarche, Benoît; Després, Jean-Pierre

2017-06-13

Chronic overconsumption of sugar-sweetened beverages (SSBs) is amongst the dietary factors most consistently found to be associated with obesity, type 2 diabetes (T2D) and cardiovascular disease (CVD) risk in large epidemiological studies. Intervention studies have shown that SSB overconsumption increases intra-abdominal obesity and ectopic lipid deposition in the liver, and also exacerbates cardiometabolic risk. Similar to the prevalence of obesity and T2D, national surveys of food consumption have shown that chronic overconsumption of SSBs is skyrocketing in many parts of the world, yet with marked heterogeneity across countries. SSB overconsumption is also particularly worrisome among children and adolescents. Although the relationships between SSB overconsumption and obesity, T2D, and CVD are rather consistent in epidemiological studies, it has also been shown that SSB overconsumption is part of an overall poor dietary pattern and is particularly prevalent among subgroups of the population with low socioeconomic status, thereby questioning the major focus on SSBs to target/prevent cardiometabolic diseases. Public health initiatives aimed specifically at decreasing SSB overconsumption will most likely be successful in influencing SSB consumption per se. However, comprehensive strategies targeting poor dietary patterns and aiming at improving global dietary quality are likely to have much more impact in addressing the unprecedented public health challenges that we are currently facing.

Reclassification of Methanogenium tationis and Methanogenium liminatans as Methanofollis tationis gen. nov., comb. nov. and Methanofollis liminatans comb. nov. and description of a new strain of Methanofollis liminatans

NASA Technical Reports Server (NTRS)

Zellner, G.; Boone, D. R.; Keswani, J.; Whitman, W. B.; Woese, C. R.; Hagelstein, A.; Tindall, B. J.; Stackebrandt, E.

1999-01-01

Sequencing of 16S rRNA genes and phylogenetic analysis of Methanogenium tationis DSM 2702T (OCM 43T) (T = type strain) and Methanogenium liminatans GKZPZT (= DSM 4140T) as well as other members of the family Methanomicrobiaceae revealed that both species belong to a separate line of descent within this family. In addition, a new strain of Methanogenium liminatans, strain BM1 (= DSM 10196), was isolated from a butyrate-degrading, fluidized bed reactor and characterized. Cells of both species are mesophilic, highly irregular cocci that use H2/CO2 and formate for growth and methanogenesis. In addition, Methanogenium liminatans strains GKZPZT and BM1 used 2-propanol/CO2, 2-butanol/CO2 and cyclopentanol/CO2. Both species contained diether and tetraether lipids. The polar lipids comprised amino-phosphopentanetetrol derivatives, which appear to be characteristic lipids within the family Methanomicrobiaceae. The pattern of glycolipids, phosphoglycolipids and amino-phosphoglycolipids was consistent with the assignment of these two species to a taxon within the family Methanomicrobiaceae, but also permitted them to be distinguished from other higher taxa within this family. The G+C contents of the DNA of Methanogenium tationis and Methanogenium liminatans were 54 and 60 mol% (Tm and HPLC), respectively. On the basis of the data presented, the transfer of Methanogenium tationis and Methanogenium liminatans to the genus Methanofollis gen. nov. as Methanofollis tationis comb. nov. and Methanofollis liminatans comb. nov., respectively, is proposed, with Methanofollis tationis as the type species.

Lipid Accumulation from Glucose and Xylose in an Engineered, Naturally Oleaginous Strain of Saccharomyces cerevisiae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knoshaug, Eric P; Van Wychen, Stefanie R; Zhang, Min

Saccharomyces cerevisiae, a well-known industrial yeast for alcoholic fermentation, is not historically known to accumulate lipids. Four S. cerevisiae strains used in industrial applications were screened for their ability to accumulate neutral lipids. Only one, D5A, was found to accumulate up to 20% dry cell weight (dcw) lipids. This strain was further engineered by knocking out ADP-activated serine/threonine kinase (SNF1) which increased lipid accumulation to 35% dcw lipids. In addition, we engineered D5A to utilize xylose and found that D5A accumulates up to 37% dcw lipids from xylose as the sole carbon source. Further we over-expressed different diacylglycerol acyltransferase (DGA1)more » genes and boosted lipid accumulation to 50%. Fatty acid speciation showed that 94% of the extracted lipids consisted of 5 fatty acid species, C16:0 (palmitic), C16:1n7 (palmitoleic), C18:0 (stearic), C18:1n7 (vaccenic), and C18:1n9 (oleic), while the relative distributions changed depending on growth conditions. In addition, this strain accumulated lipids concurrently with ethanol production.« less

TRITON HYPERLIPEMIA IN DOGS

PubMed Central

Scanu, Angelo; Oriente, Pasquale; Szajewski, Janusz M.; McCormack, Lawrence J.; Page, Irvine H.

1961-01-01

Fourteen dogs, fed a regular diet and given 250 mg/kg of triton (a non-ionic surface-active agent) intravenously every 4th day, exhibited a progressively severe hyperlipemia. Serum triglycerides were the first to increase. Cholesterol, mostly in the free form, and phospholipids showed elevation only at a later stage and increased at almost identical rates. The plasma-free fatty acid concentration was from 2 to 3 times above normal. With establishment of sustained hyperlipemia, there was reduction, followed by total disappearance, of the high density D 1.063 to 1.21 lipoprotein. Most of the cholesterol and phospholipids (70 to 75 per cent of the total) were found in the D 1.006 to 1.063 lipoprotein class, the remainder in the D < 1.006 class. Triglycerides were almost evenly distributed between these two classes. The concentration of the serum lipoprotein proteins was within normal limits. All of the animals died within from 4 to 5 months after receiving the first injection of triton. Autopsy findings consistently showed: (a) numerous lipidladen macrophages in the liver, spleen, and lymph nodes; (b) significant depletion of all fat stores; (c) presence of lipids, either free or engulfed in macrophages (foam cells), in the subintima of the coronary arteries, aorta, and pulmonary arteries, indicating an early stage of atherosclerosis. Concurrent daily administration of heparin (5 mg per kilogram of body weight) did not substantially change the course of the disease. Withdrawal of triton from animals that had been receiving the detergent for from 3 to 4 months, elicited a slow return to normal of the lipid pattern. In two dogs killed when normolipemia was reestablished, all tissues were normal with the minor exception of a few hepatic macrophages still laden with sudanophilic material. It is postulated that the primary action of the injected triton was on the lipid moieties of plasma lipoproteins with formation of complexes, which, as foreign bodies, were preferentially taken up by the cells of the reticuloendothelial system. Depletion of fat stores was probably secondary to increased lipid mobilization, as an attempt by these tissues to supply energy to the parenchymal cells unable to utilize triton-bound lipids. PMID:13747053

Study on the regulatory mechanism of the lipid metabolism pathways during chicken male germ cell differentiation based on RNA-seq.

PubMed

Zuo, Qisheng; Li, Dong; Zhang, Lei; Elsayed, Ahmed Kamel; Lian, Chao; Shi, Qingqing; Zhang, Zhentao; Zhu, Rui; Wang, Yinjie; Jin, Kai; Zhang, Yani; Li, Bichun

2015-01-01

Here, we explore the regulatory mechanism of lipid metabolic signaling pathways and related genes during differentiation of male germ cells in chickens, with the hope that better understanding of these pathways may improve in vitro induction. Fluorescence-activated cell sorting was used to obtain highly purified cultures of embryonic stem cells (ESCs), primitive germ cells (PGCs), and spermatogonial stem cells (SSCs). The total RNA was then extracted from each type of cell. High-throughput analysis methods (RNA-seq) were used to sequence the transcriptome of these cells. Gene Ontology (GO) analysis and the KEGG database were used to identify lipid metabolism pathways and related genes. Retinoic acid (RA), the end-product of the retinol metabolism pathway, induced in vitro differentiation of ESC into male germ cells. Quantitative real-time PCR (qRT-PCR) was used to detect changes in the expression of the genes involved in the retinol metabolic pathways. From the results of RNA-seq and the database analyses, we concluded that there are 328 genes in 27 lipid metabolic pathways continuously involved in lipid metabolism during the differentiation of ESC into SSC in vivo, including retinol metabolism. Alcohol dehydrogenase 5 (ADH5) and aldehyde dehydrogenase 1 family member A1 (ALDH1A1) are involved in RA synthesis in the cell. ADH5 was specifically expressed in PGC in our experiments and aldehyde dehydrogenase 1 family member A1 (ALDH1A1) persistently increased throughout development. CYP26b1, a member of the cytochrome P450 superfamily, is involved in the degradation of RA. Expression of CYP26b1, in contrast, decreased throughout development. Exogenous RA in the culture medium induced differentiation of ESC to SSC-like cells. The expression patterns of ADH5, ALDH1A1, and CYP26b1 were consistent with RNA-seq results. We conclude that the retinol metabolism pathway plays an important role in the process of chicken male germ cell differentiation.

Miscibility, chain packing, and hydration of 1-palmitoyl-2-oleoyl phosphatidylcholine and other lipids in surface phases.

PubMed

Smaby, J M; Brockman, H L

1985-11-01

The miscibility of 1-palmitoyl-2-oleoyl phosphatidylcholine with triolein, 1,2-diolein, 1,3-diolein, 1(3)-monoolein, oleyl alcohol, methyl oleate, oleic acid, and oleyl cyanide (18:1 lipids) was studied at the argon-water interface. The isothermal phase diagrams for the mixtures at 24 degrees were characterized by two compositional regions. At the limit of miscibility with lower mol fractions of 18:1 lipid, the surface pressure was composition-independent, but above a mixture-specific stoichiometry, surface pressure at the limit of miscibility was composition-dependent. From the two-dimensional phase rule, it was determined that at low mol fractions of 18:1 lipids, the surface consisted of phospholipid and a preferred packing array or complex of phospholipid and 18:1 lipid, whereas, above the stoichiometry of the complex, the surface phase consisted of complex and excess 18:1 lipids. In both regions of the phase diagram, mixing along the phase boundary was apparently ideal allowing application of an equation of state described earlier (J. M. Smaby and H. L. Brockman, 1984, Biochemistry, 23:3312-3316). From such analysis, apparent partial molecular areas and hydrations for phospholipid, complex, and 18:1 lipid were obtained. Comparison of these calculated parameters for the complexed and uncomplexed states shows that the aliphatic moieties behave independently of polar head group. The transition of each 18:1 chain to the complexed state involves the loss of about one interfacial water molecule and its corresponding area. For 18:1 lipids with more than one chain another two water molecules per additional chain are present in both states but contribute little to molecular area. In contrast to 18:1 lipids, the phospholipid area and hydration change little upon complexation. The uniformity of chain packing and hydration behavior among 18:1 lipid species contrasts with complex stoichiometries that vary from 0.04 to 0.65. This suggests that the stoichiometry of the preferred packing array is determined by interactions involving the more polar moieties of the 18:1 lipids and the phospholipid.

Different composition and distribution patterns of mineral-protected versus hydrolyzable lipids in shrubland soils

NASA Astrophysics Data System (ADS)

Cai, Yue; Tang, Zhiyao; Xiong, Gaoming; Xie, Zongqiang; Liu, Zongguang; Feng, Xiaojuan

2017-09-01

Mineral protection is known as an important mechanism stabilizing soil organic carbon (SOC). However, the composition, sources, and variations of mineral-protected SOC remain poorly constrained. To fill this knowledge gap, we used hydrofluoric acid to demineralize soil matrix and compared the sources and distribution of mineral-protected lipids (ML) versus hydrolyzable lipids (HL) of four typical Chinese shrubland soils. ML was found to represent a sizable fraction (9-32%) of total aliphatic lipids (including n-alkanols; n-alkanoic acids; α,ω-alkanedioic acids; hydroxyalkanoic acids; and midchain-substituted acids) in all soils. Based on carbon chain length and branch positions, microbe- and plant-derived lipids were distinguished. No significant difference was found in the ratio of microbe- to plant-derived lipids in ML versus HL, implying that plant and microbial inputs are equally important for the mineral-associated soil lipids. However, ML contained a higher proportion of nonspecific lipids, especially at depths. Furthermore, to evaluate key environmental variable(s) controlling the distribution of different lipid components, a multiple stepwise regression analysis was conducted. Notably, ML was mainly affected by SOC-to-nitrogen ratio instead of mineralogical properties, implying that the accrual of mineral-associated soil lipids relies strongly on organic matter properties. Collectively, our findings provide novel insights on sources and accumulation mechanisms of mineral-protected soil lipids. SOC decomposition and subsequent accretion of degradation products appear to be vital for the sequestration of mineral-associated soil lipids and warrant better recognition in the investigations of stable soil carbon accumulation mechanisms.

Assessment of storage lipid accumulation patterns in eucalanoid copepods from the eastern tropical Pacific Ocean

NASA Astrophysics Data System (ADS)

Cass, Christine J.; Daly, Kendra L.; Wakeham, Stuart G.

2014-11-01

Members of the copepod family Eucalanidae are widely distributed throughout the world's oceans and have been noted for their accumulation of storage lipids in high- and low-latitude environments. However, little is known about the lipid composition of eucalanoid copepods in low-latitude environments. The purpose of this study was to examine fatty acid and alcohol profiles in the storage lipids (wax esters and triacylglycerols) of Eucalanus inermis, Rhincalanus rostrifrons, R. nasutus, Pareucalanus attenuatus, and Subeucalanus subtenuis, collected primarily in the eastern tropical north Pacific near the Tehuantepec Bowl and Costa Rica Dome regions, noted for its oxygen minimum zone, during fall 2007 and winter 2008/2009. Adult copepods and particulate material were collected in the upper 50 m and from 200 to 300 m in the upper oxycline. Lipid profiles of particulate matter were generated to help ascertain information on ecological strategies of these species and on differential accumulation of dietary and modified fatty acids in the wax ester and triacylglycerol storage lipid components of these copepods in relation to their vertical distributions around the oxygen minimum zone. Additional data on phospholipid fatty acid and sterol/fatty alcohol fractions were also generated to obtain a comprehensive lipid data set for each sample. Rhincalanus spp. accumulated relatively large amounts of storage lipids (31-80% of dry mass (DM)), while E. inermis had moderate amounts (2-9% DM), and P. attenuatus and S. subtenuis had low quantities of storage lipid (0-1% DM). E. inermis and S. subtenuis primarily accumulated triacylglycerols (>90% of storage lipids), while P. attenuatus and Rhincalanus spp. primarily accumulated wax esters (>84% of storage lipids). Based on previously generated molecular phylogenies of the Eucalanidae family, these results appear to support genetic predisposition as a major factor explaining why a given species accumulates primarily triacylglycerols or wax esters, and also potentially dictating major fatty acid and alcohol accumulation patterns within the more highly modified wax ester fraction. Comparisons of fatty acid profiles between triacylglycerol and wax ester components in copepods with that in available prey suggested that copepod triacylglycerols were more reflective of dietary fatty acids, while wax esters contained a higher proportion of modified or de novo synthesized forms. Sterols and phospholipid fatty acids were similar between species, confirming high levels of regulation within these components. Similarities between triacylglycerol fatty acid profiles of E. inermis collected in surface waters and at >200 m depth indicate little to no feeding during their ontogenetic migration to deeper, low-oxygen waters.

Lipid extraction from microalgae using a single ionic liquid

DOEpatents

Salvo, Roberto Di; Reich, Alton; Dykes, Jr., H. Waite H.; Teixeira, Rodrigo

2013-05-28

A one-step process for the lysis of microalgae cell walls and separation of the cellular lipids for use in biofuel production by utilizing a hydrophilic ionic liquid, 1-butyl-3-methylimidazolium. The hydrophilic ionic liquid both lyses the microalgae cell walls and forms two immiscible layers, one of which consists of the lipid contents of the lysed cells. After mixture of the hydrophilic ionic liquid with a suspension of microalgae cells, gravity causes a hydrophobic lipid phase to move to a top phase where it is removed from the mixture and purified. The hydrophilic ionic liquid is recycled to lyse new microalgae suspensions.

A single step reversed-phase high performance liquid chromatography separation of polar and non-polar lipids.

PubMed

Olsson, Petter; Holmbäck, Jan; Herslöf, Bengt

2014-11-21

This paper reports a simple chromatographic system to separate lipids classes as well as their molecular species. By the use of phenyl coated silica as stationary phase in combination with a simple mobile phase consisting of methanol and water, all tested lipid classes elute within 30 min. Furthermore, a method to accurately predict retention times of specific lipid components for this type of chromatography is presented. Common detection systems were used, namely evaporative light scattering detection (ELSD), charged aerosol detection (CAD), electrospray mass spectrometry (ESI-MS), and UV detection. Copyright © 2014 Elsevier B.V. All rights reserved.

Archaeal lipids in oral delivery of therapeutic peptides.

PubMed

Jacobsen, Ann-Christin; Jensen, Sara M; Fricker, Gert; Brandl, Martin; Treusch, Alexander H

2017-10-15

Archaea contain membrane lipids that differ from those found in the other domains of life (Eukarya and Bacteria). These lipids consist of isoprenoid chains attached via ether bonds to the glycerol carbons at the sn-2,3 positions. Two types of ether lipids are known, polar diether lipids and bipolar tetraether lipids. The inherent chemical stability and unique membrane-spanning characteristics of tetraether lipids render them interesting for oral drug delivery purposes. Archaeal lipids form liposomes spontaneously (archaeosomes) and may be incorporated in conventional liposomes (mixed vesicles). Both types of liposomes are promising to protect their drug cargo, such as therapeutic peptides, against the acidic environment of the stomach and proteolytic degradation in the intestine. They appear to withstand lipolytic enzymes and bile salts and may thus deliver orally administered therapeutic peptides to distant sections of the intestine or to the colon, where they may be absorbed, eventually by the help of absorption enhancers. Archaeal lipids and their semisynthetic derivatives may thus serve as biological source for the next generation oral drug delivery systems. The aim of this review is to present a systematic overview over existing literature on archaea carrying diether and tetraether lipids, lipid diversity, means of lipid extraction and purification, preparation and in vitro stability studies of archaeal lipid-based liposomal drug carriers and in vivo proof-of concepts studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Structure and interactions in biomaterials based on membrane-biopolymer self-assembly

NASA Astrophysics Data System (ADS)

Koltover, Ilya

Physical and chemical properties of artificial pure lipid membranes have been extensively studied during the last two decades and are relatively well understood. However, most real membrane systems of biological and biotechnological importance incorporate macromolecules either embedded into the membranes or absorbed onto their surfaces. We have investigated three classes of self-assembled membrane-biopolymer biomaterials: (i) Structure, interactions and stability of the two-dimensional crystals of the integral membrane protein bacteriorhodopsin (bR). We have conducted a synchrotron x-ray diffraction study of oriented bR multilayers. The important findings were as follows: (1) the protein 2D lattice exhibited diffraction patterns characteristic of a 2D solid with power-law decay of in-plane positional correlations, which allowed to measure the elastic constants of protein crystal; (2) The crystal melting temperature was a function of the multilayer hydration, reflecting the effect of inter-membrane repulsion on the stability of protein lattice; (3) Preparation of nearly perfect (mosaicity < 0.04° ) multilayers of fused bR membranes permitted, for the first time, application of powerful interface-sensitive x-ray scattering techniques to a membrane-protein system. (ii) Interactions between the particles chemically attached or absorbed onto the surfaces of flexible giant phospholipid vesicles. Using video-enhanced light microscopy we have observed a membrane-distortion induced attraction between the particles with the interaction range of the order of particle diameter. Fluid membranes decorated with many particles exhibited: (i) a finite-sized two-dimensional closed packed aggregates and (ii) a one-dimensional ring-like aggregates. (iii) Structure, stability and interactions in the cationic lipid-DNA complexes. Cationic liposomes complexed with DNA are among the most promising synthetic non-viral carriers of DNA vectors currently used in gene therapy applications. We have established that DNA complexes with cationic lipid (DOTAP) and a neutral lipid (DOPC) have a compact multilayer liquid crystalline structure ( L ca ) with DNA intercalated between the lipid bilayers in a periodic 2D smectic phase. Furthermore, a different 2D columnar phase of complexes was found in mixtures with a transfectionen-hancing lipid DOPE. This structure ( HcII ) derived from synchrotron x-ray diffraction consists of DNA coated by cationic lipid monolayers and arranged on a two-dimensional hexagonal lattice. Optical microscopy revealed that the L ca complexes bind stably to anionic vesicles (models of cellular membranes), whereas the more transfectant HcII complexes are unstable, rapidly fusing and releasing DNA upon adhering to anionic vesicles.

Influence of iron solubility and charged surface-active compounds on lipid oxidation in fatty acid ethyl esters containing association colloids.

PubMed

Homma, Rika; Johnson, David R; McClements, D Julian; Decker, Eric A

2016-05-15

The impact of iron compounds with different solubilities on lipid oxidation was studied in the presence and absence of association colloids. Iron (III) sulfate only accelerated lipid oxidation in the presence of association colloids while iron (III) oleate accelerated oxidation in the presence and absence of association colloids. Further, iron (III) oxide retarded lipid oxidation both with and without association colloids. The impact of charged association colloids on lipid oxidation in ethyl oleate was also investigated. Association colloids consisting of the anionic surface-active compound dodecyl sulphosuccinate sodium salt (AOT), cationic surface-active compound hexadecyltrimethylammonium bromide (CTAB), and nonionic surface-active compound 4-(1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol (Triton X-100) retarded, promoted, and had no effect on lipid oxidation rates, respectively. These results indicate that the polarity of metal compounds and the charge of association colloids play a big role in lipid oxidation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nanostructured Lipid Carriers (NLC) as Vehicles for Topical Administration of Sesamol: In Vitro Percutaneous Absorption Study and Evaluation of Antioxidant Activity.

PubMed

Puglia, Carmelo; Lauro, Maria Rosaria; Offerta, Alessia; Crascì, Lucia; Micicchè, Lucia; Panico, Anna Maria; Bonina, Francesco; Puglisi, Giovanni

2017-03-01

Sesamol is a natural phenolic compound extracted from Sesamum indicum seed oil. Sesamol is endowed with several beneficial effects, but its use as a topical agent is strongly compromised by unfavorable chemical-physical properties. Therefore, to improve its characteristics, the aim of the present work was the formulation of nanostructured lipid carriers as drug delivery systems for topical administration of sesamol.Two different nanostructured lipid carrier systems have been produced based on the same solid lipid (Compritol® 888 ATO) but in a mixture with two different kinds of oil phase such as Miglyol® 812 (nanostructured lipid carrier-M) and sesame oil (nanostructured lipid carrier-PLUS). Morphology and dimensional distribution of nanostructured lipid carriers have been characterized by differential scanning calorimetry and photon correlation spectroscopy, respectively. The release pattern of sesamol from nanostructured lipid carriers was evaluated in vitro determining drug percutaneous absorption through excised human skin. Furthermore, an oxygen radical absorbance capacity assay was used to determine their antioxidant activity.From the results obtained, the method used to formulate nanostructured lipid carriers led to a homogeneous dispersion of particles in a nanometric range. Sesamol has been encapsulated efficiently in both nanostructured lipid carriers, with higher encapsulation efficiency values (> 90 %) when sesame oil was used as the oil phase (nanostructured lipid carrier-PLUS). In vitro evidences show that nanostructured lipid carrier dispersions were able to control the rate of sesamol diffusion through the skin, with respect to the reference formulations.Furthermore, the oxygen radical absorbance capacity assay pointed out an interesting and prolonged antioxidant activity of sesamol, especially when vehiculated by nanostructured lipid carrier-PLUS. Georg Thieme Verlag KG Stuttgart · New York.

Development and evaluation of nanostructured lipid carrier-based hydrogel for topical delivery of 5-fluorouracil

PubMed Central

Rajinikanth, Paruvathanahalli Siddalingam; Chellian, Jestin

2016-01-01

The aim of this study was to develop a nanostructured lipid carrier (NLC)-based hydrogel and study its potential for the topical delivery of 5-fluorouracil (5-FU). Precirol® ATO 5 (glyceryl palmitostearate) and Labrasol® were selected as the solid and liquid lipid phases, respectively. Poloxamer 188 and Solutol® HS15 (polyoxyl-15-hydroxystearate) were selected as surfactants. The developed lipid formulations were dispersed in 1% Carbopol® 934 (poly[acrylic acid]) gel medium in order to maintain the topical application consistency. The average size, zeta potential, and polydispersity index for the 5-FU-NLC were found to be 208.32±8.21 nm, −21.82±0.40 mV, and 0.352±0.060, respectively. Transmission electron microscopy study revealed that 5-FU-NLC was <200 nm in size, with a spherical shape. In vitro drug permeation studies showed a release pattern with initial burst followed by sustained release, and the rate of 5-FU permeation was significantly improved for 5-FU-NLC gel (10.27±1.82 μg/cm2/h) as compared with plain 5-FU gel (2.85±1.12 μg/cm2/h). Further, skin retention studies showed a significant retention of 5-FU from the NLC gel (91.256±4.56 μg/cm2) as compared with that from the 5-FU plain gel (12.23±3.86 μg/cm2) in the rat skin. Skin irritation was also significantly reduced with 5-FU-NLC gel as compared with 5-FU plain gel. These results show that the prepared 5-FU-loaded NLC has high potential to improve the penetration of 5-FU through the stratum corneum, with enormous retention and with minimal skin irritation, which is the prerequisite for topically applied formulations. PMID:27785014

Anisotropic 2H-nuclear magnetic resonance spin-lattice relaxation in cerebroside- and phospholipid-cholesterol bilayer membranes.

PubMed

Siminovitch, D J; Ruocco, M J; Olejniczak, E T; Das Gupta, S K; Griffin, R G

1988-09-01

The axially symmetric powder pattern 2H-nuclear magnetic resonance (NMR) lineshapes observed in the liquid crystalline phase of pure lipid or lipid/cholesterol bilayers are essentially invariant to temperature, or, equivalently, to variations in the correlation times characterizing C-2H bond reorientations. In either of these melted phases, where correlation times for C-2H bond motions are shorter than 10(-7) s, information on the molecular dynamics of the saturated hydrocarbon chain would be difficult to obtain using lineshape analyses alone, and one must resort to other methods, such as the measurement of 2H spin-lattice relaxation rates, in order to obtain dynamic information. In pure lipid bilayers, the full power of the spin-lattice relaxation technique has yet to be realized, since an important piece of information, namely the orientation dependence of the 2H spin-lattice relaxation rates is usually lost due to orientational averaging of T1 by rapid lateral diffusion. Under more favorable circumstances, such as those encountered in the lipid/cholesterol mixtures of this study, the effects of orientational averaging by lateral diffusion are nullified, due to either a marked reduction (by at least an order of magnitude) in the diffusion rate, or a marked increase in the radii of curvature of the liposomes. In either case, the angular dependence of 2H spin-lattice relaxation is accessible to experimental study, and can be used to test models of molecular dynamics in these systems. Simulations of the partially recovered lineshapes indicate that the observed T1 anisotropies are consistent with large amplitude molecular reorientation of the C-2H bond among a finite number of sites. Furthermore, from the observed orientation dependence of the 2H spin-lattice relaxation rates, we conclude that order director fluctuations cannot provide the dominant relaxation pathway for acyl chain deuterons.

21-Methylpyrenyl-cholesterol stably and specifically associates with lipoprotein peripheral hemi-membrane: A new labelling tool

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaibelet, Gérald; CEA, SB2SM and UMR8221 CNRS, IBiTec-Saclay, Gif-sur-Yvette; Tercé, François

Highlights: •21-Methylpyrenyl-cholesterol specifically and stably associates to lipoproteins. •It is not esterified by LCAT, and thus reliably labels their peripheral hemi-membrane. •HDL vs. LDL are well distinguishable by various fluorescent labelling characteristics. •LDL peripheral hemi-membrane harbors cholesterol-rich ordered lipid (micro)domains. •Cultured cells can be stained by such labelled lipoproteins-mediated delivery. -- Abstract: Lipoproteins are important biological components. However, they have few convenient fluorescent labelling probes currently reported, and their physiological reliability can be questioned. We compared the association of two fluorescent cholesterol derivatives, 22-nitrobenzoxadiazole-cholesterol (NBD-Chol) and 21-methylpyrenyl-cholesterol (Pyr-met-Chol), to serum lipoproteins and to purified HDL and LDL. Both lipoproteins couldmore » be stably labelled by Pyr-met-Chol, but virtually not by NBD-Chol. At variance with NBD-Chol, LCAT did not esterify Pyr-met-Chol. The labelling characteristics of lipoproteins by Pyr-met-Chol were well distinguishable between HDL and LDL, regarding dializability, associated probe amount and labelling kinetics. We took benefit of the pyrene labelling to approach the structural organization of LDL peripheral hemi-membrane, since Pyr-met-Chol-labelled LDL, but not HDL, presented a fluorescence emission of pyrene excimers, indicating that the probe was present in an ordered lipid micro-environment. Since the peripheral membrane of LDL contains more sphingomyelin (SM) than HDL, this excimer formation was consistent with the existence of cholesterol- and SM-enriched lipid microdomains in LDL, as already suggested in model membranes of similar composition and reminiscent to the well-described “lipid rafts” in bilayer membranes. Finally, we showed that Pyr-met-Chol could stain cultured PC-3 cells via lipoprotein-mediated delivery, with a staining pattern well different to that observed with NBD-Chol non-specifically delivered to the cells.« less

Vegetarian diet, change in dietary patterns, and diabetes risk: a prospective study.

PubMed

Chiu, Tina H T; Pan, Wen-Harn; Lin, Ming-Nan; Lin, Chin-Lon

2018-03-09

Vegetarian diets are inversely associated with diabetes in Westerners but their impact on Asians-whose pathophysiology differ from Westerners-is unknown. We aim to investigate the association between a vegetarian diet, change in dietary patterns and diabetes risk in a Taiwanese Buddhist population. We prospectively followed 2918 non-smoking, non-alcohol drinking Buddhists free of diabetes, cancer, and cardiovascular diseases at baseline, for a median of 5 years, with 183 incident diabetes cases confirmed. Diet was assessed through a validated food frequency questionnaire at baseline and a simple questionnaire during follow-ups. Incident cases of diabetes were ascertained through follow-up questionnaires, fasting glucose and HbA1C. Stratified Cox Proportional Hazards Regression was used to assess the effect of diets on risk of diabetes. Consistent vegetarian diet was associated with 35% lower hazards (HR: 0.65, 95% CI: 0.46, 0.92), while converting from a nonvegetarian to a vegetarian pattern was associated with 53% lower hazards (HR: 0.47, 95% CI: 0.30, 0.71) for diabetes, comparing with nonvegetarians while adjusting for age, gender, education, physical activity, family history of diabetes, follow-up methods, use of lipid-lowering medications, and baseline BMI. Vegetarian diet and converting to vegetarian diet may protect against diabetes independent of BMI among Taiwanese.

Interaction of Local Anesthetics with Biomembranes Consisting of Phospholipids and Cholesterol: Mechanistic and Clinical Implications for Anesthetic and Cardiotoxic Effects

PubMed Central

2013-01-01

Despite a long history in medical and dental application, the molecular mechanism and precise site of action are still arguable for local anesthetics. Their effects are considered to be induced by acting on functional proteins, on membrane lipids, or on both. Local anesthetics primarily interact with sodium channels embedded in cell membranes to reduce the excitability of nerve cells and cardiomyocytes or produce a malfunction of the cardiovascular system. However, the membrane protein-interacting theory cannot explain all of the pharmacological and toxicological features of local anesthetics. The administered drug molecules must diffuse through the lipid barriers of nerve sheaths and penetrate into or across the lipid bilayers of cell membranes to reach the acting site on transmembrane proteins. Amphiphilic local anesthetics interact hydrophobically and electrostatically with lipid bilayers and modify their physicochemical property, with the direct inhibition of membrane functions, and with the resultant alteration of the membrane lipid environments surrounding transmembrane proteins and the subsequent protein conformational change, leading to the inhibition of channel functions. We review recent studies on the interaction of local anesthetics with biomembranes consisting of phospholipids and cholesterol. Understanding the membrane interactivity of local anesthetics would provide novel insights into their anesthetic and cardiotoxic effects. PMID:24174934

Advances in nanopatterned and nanostructured supported lipid membranes and their applications.

PubMed

Reimhult, Erik; Baumann, Martina; Kaufmann, Stefan; Kumar, Karthik; Spycher, Philipp

2010-01-01

Lipid membranes are versatile and convenient alternatives to study the properties of natural cell membranes. Self-assembled, artificial, substrate-supported lipid membranes have taken a central role in membrane research due to a combination of factors such as ease of creation, control over complexity, stability and the applicability of a large range of different analytical techniques. While supported lipid bilayers have been investigated for several decades, recent advances in the understanding of the assembly of such membranes from liposomes have spawned a renaissance in the field. Supported lipid bilayers are a highly promising tool to study transmembrane proteins in their native state, an application that could have tremendous impact on, e.g. drug discovery, development of biointerfaces and as platforms for glycomics and probing of multivalent binding which requires ligand mobility. Parallel advances in microfluidics, biosensor design, micro- and nanofabrication have converged to bring self-assembled supported lipid bilayers closer to a versatile and easy to use research tool as well as closer to industrial applications. The field of supported lipid bilayer research and application is thus rapidly expanding and diversifying with new platforms continuously being proposed and developed. In order to use supported lipid bilayers for such applications several advances have to be made: decoupling of the membrane from the support while maintaining it close to the surface, making use of biologically relevant lipid compositions, patterning of lipid membranes into arrays, and application to nanostructured substrates and sensors. This review summarizes recent advances in the field which addresses these challenges.

The NMR analysis of frying oil: a very reliable method for assessment of lipid oxidation

USDA-ARS?s Scientific Manuscript database

There are many analytical methods developed for the assessment of lipid oxidation. However, one of the most challenging issues in analyzing oil oxidation is that there is lack of consistency in results obtained from different analytical methods. The major reason for the inconsistency is that most me...

IS TREATMENT ADHERENCE CONSISTENT ACROSS TIME, ACROSS DIFFERENT TREATMENTS, AND ACROSS DIAGNOSES?

PubMed Central

Simon, Gregory E; Peterson, Do; Hubbard, Rebecca

2012-01-01

Objective Examine consistency of adherence across depression treatments and consistency of adherence between depression treatments and treatments for chronic medical illness. Methods For 25,456 health plan members beginning psychotherapy for depression between 2003 and 2008, health plan records were used to examine adherence to all episodes of psychotherapy, antidepressant medication, antihypertensive medication, and lipid-lowering medication. Results Within treatments, adherence to psychotherapy in one episode predicted approximately 20% greater likelihood of subsequent psychotherapy adherence (OR 2.20, 95% CI 1.83 to 2.64). Similarly, adherence to antidepressant medication in one episode predicted approximately 20% greater likelihood of subsequent antidepressant adherence (OR 1.99, 95% CI 1.74 to 2.28). Across treatments, adherence to antidepressant medication predicted approximately 10% greater likelihood of concurrent or subsequent adherence to psychotherapy (OR 1.52, 95% CI 1.42 to 1.63), a 4% greater likelihood of adherence to antihypertensive medication (OR 1.24, 95% CI 1.14 to 1.37) and a 3% greater likelihood of adherence to lipid-lowering medication (OR 1.16, 95% CI 1.03 to 1.32). Adherence to psychotherapy predicted a 2% greater likelihood of concurrent or subsequent adherence to antihypertensive medication (OR 1.11, 95% CI 1.04 to 1.19) and was not a significant predictor of adherence to lipid-lowering medication (OR 0.99, 95% CI 0.90 to 1.18). Conclusions Adherence is moderately consistent across episodes of depression treatment. Depression treatment adherence is a statistically significant, but relatively weak, predictor of adherence to antihypertensive or lipid-lowering medication. PMID:23141589

Carbon Metabolism in Spores of the Arbuscular Mycorrhizal Fungus Glomus intraradices as Revealed by Nuclear Magnetic Resonance Spectroscopy1

PubMed Central

Bago, Berta; Pfeffer, Philip E.; Douds, David D.; Brouillette, Janine; Bécard, Guillaume; Shachar-Hill, Yair

1999-01-01

Arbuscular mycorrhizal (AM) fungi are obligate symbionts that colonize the roots of over 80% of plants in all terrestrial environments. Understanding why AM fungi do not complete their life cycle under free-living conditions has significant implications for the management of one of the world's most important symbioses. We used 13C-labeled substrates and nuclear magnetic resonance spectroscopy to study carbon fluxes during spore germination and the metabolic pathways by which these fluxes occur in the AM fungus Glomus intraradices. Our results indicate that during asymbiotic growth: (a) sugars are made from stored lipids; (b) trehalose (but not lipid) is synthesized as well as degraded; (c) glucose and fructose, but not mannitol, can be taken up and utilized; (d) dark fixation of CO2 is substantial; and (e) arginine and other amino acids are synthesized. The labeling patterns are consistent with significant carbon fluxes through gluconeogenesis, the glyoxylate cycle, the tricarboxylic acid cycle, glycolysis, non-photosynthetic one-carbon metabolism, the pentose phosphate pathway, and most or all of the urea cycle. We also report the presence of an unidentified betaine-like compound. Carbon metabolism during asymbiotic growth has features in between those presented by intraradical and extraradical hyphae in the symbiotic state. PMID:10482682

Molecular dynamics simulations on discoidal HDL particles suggest a mechanism for rotation in the apo A-I belt model.

PubMed

Klon, Anthony E; Segrest, Jere P; Harvey, Stephen C

2002-12-06

Apolipoprotein A-I (apo A-I) is the major protein component of high-density lipoprotein (HDL) particles. Elevated levels of HDL in the bloodstream have been shown to correlate strongly with a reduced risk factor for atherosclerosis. Molecular dynamics simulations have been carried out on three separate model discoidal high-density lipoprotein particles (HDL) containing two monomers of apo A-I and 160 molecules of palmitoyloleoylphosphatidylcholine (POPC), to a time-scale of 1ns. The starting structures were on the basis of previously published molecular belt models of HDL consisting of the lipid-binding C-terminal domain (residues 44-243) wrapped around the circumference of a discoidal HDL particle. Subtle changes between two of the starting structures resulted in significantly different behavior during the course of the simulation. The results provide support for the hypothesis of Segrest et al. that helical registration in the molecular belt model of apo A-I is modulated by intermolecular salt bridges. In addition, we propose an explanation for the presence of proline punctuation in the molecular belt model, and for the presence of two 11-mer helical repeats interrupting the otherwise regular pattern of 22-mer helical repeats in the lipid-binding domain of apo A-I.

Organochlorine exposure and bioaccumulation in the endangered northwest Atlantic right whale (Eubalaena glacialis) population

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weisbrod, A.V.; Shea, D.; Moore, M.J.

2000-03-01

Exposure to toxicants is one factor hypothesized to influence population growth of the northern right whale. Organochlorines in right whale skin, feces, and prey were measured and used to identify factors influencing exposure and bioaccumulation. Concentrations of 30 polychlorinated biphenyls (PCBs) and 20 pesticides in skin biopsies were consistent with other baleenopterids. Concentrations in feces and prey were two orders of magnitude less than in biopsies. In principal component analysis, organochlorines in biopsies matched those from Bay of Fundy, Canada, zooplankton, whereas feces were like Cape Cod, USA, copepods. Year of biopsy collection was the principal factor associated with differentialmore » accumulation of nonmetabolizable PCBs, 4,4{prime}-DDE, and dieldrin. Biopsies collected during winter had lower concentrations of lipid and metabolizable compounds than biopsies collected during summer. Concentrations of metabolizable PCBs increased with age in males. The bioaccumulation patterns implied that blubber burdens change annually because of the ingestion of different prey or prey from distinct locations and the release of some organochlorines stored in blubber during lipid depletion in winter. Because biopsy concentrations were lower than those found in marine mammals affected by PCBs and DDTs, the authors do not have evidence that the endangered whales bioaccumulate hazardous concentrations of organochlorines.« less

A model to resolve organochlorine pharmacokinetics in migrating humpback whales.

PubMed

Cropp, Roger; Nash, Susan Bengtson; Hawker, Darryl

2014-07-01

Humpback whales are iconic mammals at the top of the Antarctic food chain. Their large reserves of lipid-rich tissues such as blubber predispose them to accumulation of lipophilic contaminants throughout their lifetime. Changes in the volume and distribution of lipids in humpback whales, particularly during migration, could play an important role in the pharmacokinetics of lipophilic contaminants such as the organochlorine pesticide hexachlorobenzene (HCB). Previous models have examined constant feeding and nonmigratory scenarios. In the present study, the authors develop a novel heuristic model to investigate HCB dynamics in a humpback whale and its environment by coupling an ecosystem nutrient-phytoplankton-zooplankton-detritus (NPZD) model, a dynamic energy budget (DEB) model, and a physiologically based pharmacokinetic (PBPK) model. The model takes into account the seasonal feeding pattern of whales, their energy requirements, and fluctuating contaminant burdens in the supporting plankton food chain. It is applied to a male whale from weaning to maturity, spanning 20 migration and feeding cycles. The model is initialized with environmental HCB burdens similar to those measured in the Southern Ocean and predicts blubber HCB concentrations consistent with empirical concentrations observed in a southern hemisphere population of male, migrating humpback whales. Results show for the first time some important details of the relationship between energy budgets and organochlorine pharmacokinetics. © 2014 SETAC.

SAR11 lipid renovation in response to phosphate starvation

PubMed Central

Carini, Paul; Van Mooy, Benjamin A. S.; Thrash, J. Cameron; White, Angelicque; Zhao, Yanlin; Campbell, Emily O.; Fredricks, Helen F.; Giovannoni, Stephen J.

2015-01-01

Phytoplankton inhabiting oligotrophic ocean gyres actively reduce their phosphorus demand by replacing polar membrane phospholipids with those lacking phosphorus. Although the synthesis of nonphosphorus lipids is well documented in some heterotrophic bacterial lineages, phosphorus-free lipid synthesis in oligotrophic marine chemoheterotrophs has not been directly demonstrated, implying they are disadvantaged in phosphate-deplete ecosystems, relative to phytoplankton. Here, we show the SAR11 clade chemoheterotroph Pelagibacter sp. str. HTCC7211 renovates membrane lipids when phosphate starved by replacing a portion of its phospholipids with monoglucosyl- and glucuronosyl-diacylglycerols and by synthesizing new ornithine lipids. Lipid profiles of cells grown with excess phosphate consisted entirely of phospholipids. Conversely, up to 40% of the total lipids were converted to nonphosphorus lipids when cells were starved for phosphate, or when growing on methylphosphonate. Cells sequentially limited by phosphate and methylphosphonate transformed >75% of their lipids to phosphorus-free analogs. During phosphate starvation, a four-gene cluster was significantly up-regulated that likely encodes the enzymes responsible for lipid renovation. These genes were found in Pelagibacterales strains isolated from a phosphate-deficient ocean gyre, but not in other strains from coastal environments, suggesting alternate lipid synthesis is a specific adaptation to phosphate scarcity. Similar gene clusters are found in the genomes of other marine α-proteobacteria, implying lipid renovation is a common strategy used by heterotrophic cells to reduce their requirement for phosphorus in oligotrophic habitats. PMID:26056292

The sheep genome illuminates biology of the rumen and lipid metabolism.

PubMed

Jiang, Yu; Xie, Min; Chen, Wenbin; Talbot, Richard; Maddox, Jillian F; Faraut, Thomas; Wu, Chunhua; Muzny, Donna M; Li, Yuxiang; Zhang, Wenguang; Stanton, Jo-Ann; Brauning, Rudiger; Barris, Wesley C; Hourlier, Thibaut; Aken, Bronwen L; Searle, Stephen M J; Adelson, David L; Bian, Chao; Cam, Graham R; Chen, Yulin; Cheng, Shifeng; DeSilva, Udaya; Dixen, Karen; Dong, Yang; Fan, Guangyi; Franklin, Ian R; Fu, Shaoyin; Guan, Rui; Highland, Margaret A; Holder, Michael E; Huang, Guodong; Ingham, Aaron B; Jhangiani, Shalini N; Kalra, Divya; Kovar, Christie L; Lee, Sandra L; Liu, Weiqing; Liu, Xin; Lu, Changxin; Lv, Tian; Mathew, Tittu; McWilliam, Sean; Menzies, Moira; Pan, Shengkai; Robelin, David; Servin, Bertrand; Townley, David; Wang, Wenliang; Wei, Bin; White, Stephen N; Yang, Xinhua; Ye, Chen; Yue, Yaojing; Zeng, Peng; Zhou, Qing; Hansen, Jacob B; Kristensen, Karsten; Gibbs, Richard A; Flicek, Paul; Warkup, Christopher C; Jones, Huw E; Oddy, V Hutton; Nicholas, Frank W; McEwan, John C; Kijas, James; Wang, Jun; Worley, Kim C; Archibald, Alan L; Cockett, Noelle; Xu, Xun; Wang, Wen; Dalrymple, Brian P

2014-06-06

Sheep (Ovis aries) are a major source of meat, milk, and fiber in the form of wool and represent a distinct class of animals that have a specialized digestive organ, the rumen, that carries out the initial digestion of plant material. We have developed and analyzed a high-quality reference sheep genome and transcriptomes from 40 different tissues. We identified highly expressed genes encoding keratin cross-linking proteins associated with rumen evolution. We also identified genes involved in lipid metabolism that had been amplified and/or had altered tissue expression patterns. This may be in response to changes in the barrier lipids of the skin, an interaction between lipid metabolism and wool synthesis, and an increased role of volatile fatty acids in ruminants compared with nonruminant animals. Copyright © 2014, American Association for the Advancement of Science.

A network model of successive partitioning-limited solute diffusion through the stratum corneum.

PubMed

Schumm, Phillip; Scoglio, Caterina M; van der Merwe, Deon

2010-02-07

As the most exposed point of contact with the external environment, the skin is an important barrier to many chemical exposures, including medications, potentially toxic chemicals and cosmetics. Traditional dermal absorption models treat the stratum corneum lipids as a homogenous medium through which solutes diffuse according to Fick's first law of diffusion. This approach does not explain non-linear absorption and irregular distribution patterns within the stratum corneum lipids as observed in experimental data. A network model, based on successive partitioning-limited solute diffusion through the stratum corneum, where the lipid structure is represented by a large, sparse, and regular network where nodes have variable characteristics, offers an alternative, efficient, and flexible approach to dermal absorption modeling that simulates non-linear absorption data patterns. Four model versions are presented: two linear models, which have unlimited node capacities, and two non-linear models, which have limited node capacities. The non-linear model outputs produce absorption to dose relationships that can be best characterized quantitatively by using power equations, similar to the equations used to describe non-linear experimental data.

Expression pattern of L-FABP gene in different tissues and its regulation of fat metabolism-related genes in duck.

PubMed

He, Jun; Tian, Yong; Li, Jinjun; Shen, Junda; Tao, Zhengrong; Fu, Yan; Niu, Dong; Lu, Lizhi

2013-01-01

Liver fatty acid binding protein (L-FABP) is a member of intracellular lipid-binding proteins responsible for the transportation of fatty acids. The expression pattern of duck L-FABP mRNA was examined in this study by quantitative RT-PCR. The results showed that duck L-FABP gene was expressed in many tissues, including heart, lung, kidney, muscle, ovary, brain, intestine, stomach and adipocyte tissues, and highly expressed in liver. Several lipid metabolism-related genes were selected to detect the regulation of L-FABP in duck. The expression of L-FABP and lipoprotein lipase was promoted by oleic acid. The L-FABP knockdown decreased the expression levels of peroxisome proliferator-activated receptor α (PPARα), fatty acid synthase and lipoprotein lipase by 61.1, 42.3 and 53.7 %, respectively (P < 0.05), but had no influences on the mRNA levels of PPARγ and leptin receptor. L-FABP might function through the PPARα to regulate the fat metabolism-related gene expression and play important roles in lipid metabolism in duck hepatocytes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keith, Dove; Finlay, Liam; Butler, Judy

Highlights: • 24 month old rats were supplemented with 0.2% lipoic acid in the diet for 2 weeks. • Lipoic acid shifts phase of core circadian clock proteins. • Lipoic acid corrects age-induced desynchronized lipid metabolism rhythms. - Abstract: It is well established that lipid metabolism is controlled, in part, by circadian clocks. However, circadian clocks lose temporal precision with age and correlates with elevated incidence in dyslipidemia and metabolic syndrome in older adults. Because our lab has shown that lipoic acid (LA) improves lipid homeostasis in aged animals, we hypothesized that LA affects the circadian clock to achieve thesemore » results. We fed 24 month old male F344 rats a diet supplemented with 0.2% (w/w) LA for 2 weeks prior to sacrifice and quantified hepatic circadian clock protein levels and clock-controlled lipid metabolic enzymes. LA treatment caused a significant phase-shift in the expression patterns of the circadian clock proteins Period (Per) 2, Brain and Muscle Arnt-Like1 (BMAL1), and Reverse Erythroblastosis virus (Rev-erb) β without altering the amplitude of protein levels during the light phase of the day. LA also significantly altered the oscillatory patterns of clock-controlled proteins associated with lipid metabolism. The level of peroxisome proliferator-activated receptor (PPAR) α was significantly increased and acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) were both significantly reduced, suggesting that the LA-supplemented aged animals are in a catabolic state. We conclude that LA remediates some of the dyslipidemic processes associated with advanced age, and this mechanism may be at least partially through entrainment of circadian clocks.« less

Dynamic association with donor cell filopodia and lipid-modification are essential features of Wnt8a during patterning of the zebrafish neuroectoderm.

PubMed

Luz, Marta; Spannl-Müller, Stephanie; Özhan, Günes; Kagermeier-Schenk, Birgit; Rhinn, Muriel; Weidinger, Gilbert; Brand, Michael

2014-01-01

Wnt proteins are conserved signaling molecules that regulate pattern formation during animal development. Many Wnt proteins are post-translationally modified by addition of lipid adducts. Wnt8a provides a crucial signal for patterning the anteroposterior axis of the developing neural plate in vertebrates. However, it is not clear how this protein propagates from its source, the blastoderm margin, to the target cells in the prospective neural plate, and how lipid-modifications might influence Wnt8a propagation and activity. We have dynamically imaged biologically active, fluorescently tagged Wnt8a in living zebrafish embryos. We find that Wnt8a localizes to membrane-associated, punctate structures in live tissue. In Wnt8a expressing cells, these puncta are found on filopodial cellular processes, from where the protein can be released. In addition, Wnt8a is found colocalized with Frizzled receptor-containing clusters on signal receiving cells. Combining in vitro and in vivo assays, we compare the roles of conserved Wnt8a residues in cell and non-cell-autonomous signaling activity and secretion. Non-signaling Wnt8 variants show these residues can regulate Wnt8a distribution in producing cell membranes and filopodia as well as in the receiving tissue. Together, our results show that Wnt8a forms dynamic clusters found on filopodial donor cell and on signal receiving cell membranes. Moreover, they demonstrate a differential requirement of conserved residues in Wnt8a protein for distribution in producing cells and receiving tissue and signaling activity during neuroectoderm patterning.

Dynamic Association with Donor Cell Filopodia and Lipid-Modification Are Essential Features of Wnt8a during Patterning of the Zebrafish Neuroectoderm

PubMed Central

Luz, Marta; Spannl-Müller, Stephanie; Özhan, Günes; Kagermeier-Schenk, Birgit; Rhinn, Muriel; Weidinger, Gilbert; Brand, Michael

2014-01-01

Background Wnt proteins are conserved signaling molecules that regulate pattern formation during animal development. Many Wnt proteins are post-translationally modified by addition of lipid adducts. Wnt8a provides a crucial signal for patterning the anteroposterior axis of the developing neural plate in vertebrates. However, it is not clear how this protein propagates from its source, the blastoderm margin, to the target cells in the prospective neural plate, and how lipid-modifications might influence Wnt8a propagation and activity. Results We have dynamically imaged biologically active, fluorescently tagged Wnt8a in living zebrafish embryos. We find that Wnt8a localizes to membrane-associated, punctate structures in live tissue. In Wnt8a expressing cells, these puncta are found on filopodial cellular processes, from where the protein can be released. In addition, Wnt8a is found colocalized with Frizzled receptor-containing clusters on signal receiving cells. Combining in vitro and in vivo assays, we compare the roles of conserved Wnt8a residues in cell and non-cell-autonomous signaling activity and secretion. Non-signaling Wnt8 variants show these residues can regulate Wnt8a distribution in producing cell membranes and filopodia as well as in the receiving tissue. Conclusions Together, our results show that Wnt8a forms dynamic clusters found on filopodial donor cell and on signal receiving cell membranes. Moreover, they demonstrate a differential requirement of conserved residues in Wnt8a protein for distribution in producing cells and receiving tissue and signaling activity during neuroectoderm patterning. PMID:24427298

Pharmacological modulation of dietary lipid-induced cerebral capillary dysfunction: Considerations for reducing risk for Alzheimer's disease.

PubMed

Pallebage-Gamarallage, Menuka; Takechi, Ryusuke; Lam, Virginie; Elahy, Mina; Mamo, John

2016-01-01

An increasing body of evidence suggests that cerebrovascular dysfunction and microvessel disease precede the evolution of hallmark pathological features that characterise Alzheimer's disease (AD), consistent with a causal association for onset or progression. Recent studies, principally in genetically unmanipulated animal models, suggest that chronic ingestion of diets enriched in saturated fats and cholesterol may compromise blood-brain barrier (BBB) integrity resulting in inappropriate blood-to-brain extravasation of plasma proteins, including lipid macromolecules that may be enriched in amyloid-β (Aβ). Brain parenchymal retention of blood proteins and lipoprotein bound Aβ is associated with heightened neurovascular inflammation, altered redox homeostasis and nitric oxide (NO) metabolism. Therefore, it is a reasonable proposition that lipid-lowering agents may positively modulate BBB integrity and by extension attenuate risk or progression of AD. In addition to their robust lipid lowering properties, reported beneficial effects of lipid-lowering agents were attributed to their pleiotropic properties via modulation of inflammation, oxidative stress, NO and Aβ metabolism. The review is a contemporary consideration of a complex body of literature intended to synthesise focussed consideration of mechanisms central to regulation of BBB function and integrity. Emphasis is given to dietary fat driven significant epidemiological evidence consistent with heightened risk amongst populations consuming greater amounts of saturated fats and cholesterol. In addition, potential neurovascular benefits associated with the use of hypolipidemic statins, probucol and fenofibrate are also presented in the context of lipid-lowering and pleiotropic properties.

Influence of abscisic acid on growth, biomass and lipid yield of Scenedesmus quadricauda under nitrogen starved condition.

PubMed

Sulochana, Sujitha Balakrishnan; Arumugam, Muthu

2016-08-01

Scenedesmus quadricauda, accumulated more lipid but with a drastic reduction in biomass yield during nitrogen starvation. Abscisic acid (ABA) being a stress responsible hormone, its effect on growth and biomass with sustainable lipid yield during nitrogen depletion was studied. The result revealed that the ABA level shoots up at 24h (27.21pmol/L) during the onset of nitrogen starvation followed by a sharp decline. The external supplemented ABA showed a positive effect on growth pattern (38×10(6)cells/ml) at a lower concentration. The dry biomass yield is also increasing up to 2.1 fold compared to nitrogen deficient S. quadricauda. The lipid content sustains in 1 and 2μM concentration of ABA under nitrogen-deficient condition. The fatty acid composition of ABA treated S. quadricauda cultures with respect to nitrogen-starved cells showed 11.17% increment in saturated fatty acid content, the desired lipid composition for biofuel application. Copyright © 2016 Elsevier Ltd. All rights reserved.

Lipid transfer from plants to arbuscular mycorrhiza fungi

PubMed Central

Keymer, Andreas; Pimprikar, Priya; Wewer, Vera; Huber, Claudia; Brands, Mathias; Bucerius, Simone L; Delaux, Pierre-Marc; Klingl, Verena; von Röpenack-Lahaye, Edda; Wang, Trevor L; Eisenreich, Wolfgang; Dörmann, Peter; Parniske, Martin; Gutjahr, Caroline

2017-01-01

Arbuscular mycorrhiza (AM) symbioses contribute to global carbon cycles as plant hosts divert up to 20% of photosynthate to the obligate biotrophic fungi. Previous studies suggested carbohydrates as the only form of carbon transferred to the fungi. However, de novo fatty acid (FA) synthesis has not been observed in AM fungi in absence of the plant. In a forward genetic approach, we identified two Lotus japonicus mutants defective in AM-specific paralogs of lipid biosynthesis genes (KASI and GPAT6). These mutants perturb fungal development and accumulation of emblematic fungal 16:1ω5 FAs. Using isotopolog profiling we demonstrate that 13C patterns of fungal FAs recapitulate those of wild-type hosts, indicating cross-kingdom lipid transfer from plants to fungi. This transfer of labelled FAs was not observed for the AM-specific lipid biosynthesis mutants. Thus, growth and development of beneficial AM fungi is not only fueled by sugars but depends on lipid transfer from plant hosts. DOI: http://dx.doi.org/10.7554/eLife.29107.001 PMID:28726631

Cultivation of Chlorella vulgaris using different sources of carbon and its impact on lipid production

NASA Astrophysics Data System (ADS)

Fransiscus, Yunus; Purwanto, Edy

2017-05-01

A cultivation process of Chlorella vulgaris has been done in different treatment to investigate the optimum condition for lipid production. Firstly, autotroph and heterotroph condition have been applied to test the significance impact of carbon availability to the growth and lipid production of Chlorella vulgaris. And for the same purpose, heterotroph condition using glucose, fructose and sucrose as carbon sources was independently implemented. The growth rate of Chlorella vulgaris in autotroph condition was much slower than those in heterotroph. The different sources of carbon gave no significant different in the growth pattern, but in term of lipid production it was presented a considerable result. At lower concentration (3 and 6 gr/L) of carbon sources there was only slight different in lipid production level. At higher concentration (12 gr/L) glucose as a carbon source produced the highest result, 60.18% (w/w) compared to fructose and sucrose that produced 27.34% (w/w) and 18.19% (w/w) respectively.

The bovine seminal plasma protein PDC-109 extracts phosphorylcholine-containing lipids from the outer membrane leaflet.

PubMed

Tannert, Astrid; Kurz, Anke; Erlemann, Karl-Rudolf; Müller, Karin; Herrmann, Andreas; Schiller, Jürgen; Töpfer-Petersen, Edda; Manjunath, Puttaswamy; Müller, Peter

2007-04-01

The bovine seminal plasma protein PDC-109 modulates the maturation of bull sperm cells by removing lipids, mainly phosphatidylcholine and cholesterol, from their cellular membrane. Here, we have characterized the process of extraction of endogenous phospholipids and of their respective analogues. By measuring the PDC-109-mediated release of fluorescent phospholipid analogues from lipid vesicles and from biological membranes (human erythrocytes, bovine epididymal sperm cells), we showed that PDC-109 extracts phospholipids with a phosphorylcholine headgroup mainly from the outer leaflet of these membranes. The ability of PDC-109 to extract endogenous phospholipids from epididymal sperm cells was followed by mass spectrometry, which allowed us to characterize the fatty acid pattern of the released lipids. From these cells, PDC-109 extracted phosphatidylcholine and sphingomyelin that contained an enrichment of mono- and di-unsaturated fatty acids as well as short-chain and lyso-phosphatidylcholine species. Based on the results, a model explaining the phospholipid specificity of PDC-109-mediated lipid release is presented.

Metabolic profiles and lipoprotein lipid concentrations in non-obese and obese patients with polycystic ovarian disease.

PubMed

Mahabeer, S; Naidoo, C; Norman, R J; Jialal, I; Reddi, K; Joubert, S M

1990-10-01

Clinical parameters, androgen status and lipoprotein lipid profiles were assessed in 10 non-obese and 10 obese patients with polycystic ovarian disease (PCOD) and reference subjects matched for age, height and weight. Both obese and non-obese women with PCOD had significantly higher androgen levels when compared to the reference groups. When comparison of lipoprotein lipid profiles were made between groups, non-obese women with PCOD had significantly higher total cholesterol, triglycerides and LDL-cholesterol levels than non-obese reference subjects. Obese PCOD women manifested significantly higher total cholesterol, LDL-cholesterol, cholesterol/HDL, and LDL/HDL values than did obese reference subjects. Correlations between serum androgens and lipoprotein lipid concentrations in PCOD and normal women were unhelpful. Both non-obese and obese patients with PCOD had significantly higher systolic and diastolic blood pressures (BPs) than the reference groups. Thus, both non-obese and obese women with PCOD manifest hyperandrogenaemia which may result in a male pattern of lipoprotein lipid concentrations.

Functionalization Pattern of Graphene Oxide Sheets Controls Entry or Produces Lipid Turmoil in Phospholipid Membranes.

PubMed

Dallavalle, Marco; Bottoni, Andrea; Calvaresi, Matteo; Zerbetto, Francesco

2018-05-09

Molecular dynamics, coarse-grained to the level of hydrophobic and hydrophilic interactions, shows that graphene oxide sheets, GOSs, can pierce through the phospholipid membrane and navigate the double layer only if the hydrophilic groups are randomly dispersed in the structure. Their behavior resembles that found in similar calculations for pristine graphene sheets. If the oxidation is located at the edge of the sheets, GOSs hover over the membrane and trigger a major reorganization of the lipids. The reorganization is the largest when the radius of the edge-functionalized sheet is similar to the length of the lipophilic chain of the lipids. In the reorganization, the heads of the lipid chains form dynamical structures that pictorially resemble the swirl of water flowing down a drain. All effects maximize the interaction between hydrophobic moieties on the one hand and lipophilic fragments on the other and are accompanied by a large number of lipid flip-flops. Possible biological consequences are discussed.

Microbial Analysis of Australian Dry Lake Cores; Analogs For Biogeochemical Processes

NASA Astrophysics Data System (ADS)

Nguyen, A. V.; Baldridge, A. M.; Thomson, B. J.

2014-12-01

Lake Gilmore in Western Australia is an acidic ephemeral lake that is analogous to Martian geochemical processes represented by interbedded phyllosilicates and sulfates. These areas demonstrate remnants of a global-scale change on Mars during the late Noachian era from a neutral to alkaline pH to relatively lower pH in the Hesperian era that continues to persist today. The geochemistry of these areas could possibly be caused by small-scale changes such as microbial metabolism. Two approaches were used to determine the presence of microbes in the Australian dry lake cores: DNA analysis and lipid analysis. Detecting DNA or lipids in the cores will provide evidence of living or deceased organisms since they provide distinct markers for life. Basic DNA analysis consists of extraction, amplification through PCR, plasmid cloning, and DNA sequencing. Once the sequence of unknown DNA is known, an online program, BLAST, will be used to identify the microbes for further analysis. The lipid analysis approach consists of phospholipid fatty acid analysis that is done by Microbial ID, which will provide direct identification any microbes from the presence of lipids. Identified microbes are then compared to mineralogy results from the x-ray diffraction of the core samples to determine if the types of metabolic reactions are consistent with the variation in composition in these analog deposits. If so, it provides intriguing implications for the presence of life in similar Martian deposits.

A computer simulation approach to quantify the true area and true area compressibility modulus of biological membranes.

PubMed

Chacón, Enrique; Tarazona, Pedro; Bresme, Fernando

2015-07-21

We present a new computational approach to quantify the area per lipid and the area compressibility modulus of biological membranes. Our method relies on the analysis of the membrane fluctuations using our recently introduced coupled undulatory (CU) mode [Tarazona et al., J. Chem. Phys. 139, 094902 (2013)], which provides excellent estimates of the bending modulus of model membranes. Unlike the projected area, widely used in computer simulations of membranes, the CU area is thermodynamically consistent. This new area definition makes it possible to accurately estimate the area of the undulating bilayer, and the area per lipid, by excluding any contributions related to the phospholipid protrusions. We find that the area per phospholipid and the area compressibility modulus features a negligible dependence with system size, making possible their computation using truly small bilayers, involving a few hundred lipids. The area compressibility modulus obtained from the analysis of the CU area fluctuations is fully consistent with the Hooke's law route. Unlike existing methods, our approach relies on a single simulation, and no a priori knowledge of the bending modulus is required. We illustrate our method by analyzing 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayers using the coarse grained MARTINI force-field. The area per lipid and area compressibility modulus obtained with our method and the MARTINI forcefield are consistent with previous studies of these bilayers.

A computer simulation approach to quantify the true area and true area compressibility modulus of biological membranes

NASA Astrophysics Data System (ADS)

Chacón, Enrique; Tarazona, Pedro; Bresme, Fernando

2015-07-01

We present a new computational approach to quantify the area per lipid and the area compressibility modulus of biological membranes. Our method relies on the analysis of the membrane fluctuations using our recently introduced coupled undulatory (CU) mode [Tarazona et al., J. Chem. Phys. 139, 094902 (2013)], which provides excellent estimates of the bending modulus of model membranes. Unlike the projected area, widely used in computer simulations of membranes, the CU area is thermodynamically consistent. This new area definition makes it possible to accurately estimate the area of the undulating bilayer, and the area per lipid, by excluding any contributions related to the phospholipid protrusions. We find that the area per phospholipid and the area compressibility modulus features a negligible dependence with system size, making possible their computation using truly small bilayers, involving a few hundred lipids. The area compressibility modulus obtained from the analysis of the CU area fluctuations is fully consistent with the Hooke's law route. Unlike existing methods, our approach relies on a single simulation, and no a priori knowledge of the bending modulus is required. We illustrate our method by analyzing 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayers using the coarse grained MARTINI force-field. The area per lipid and area compressibility modulus obtained with our method and the MARTINI forcefield are consistent with previous studies of these bilayers.

Biomass and lipid production of dinoflagellates and raphidophytes in indoor and outdoor photobioreactors.

PubMed

Fuentes-Grünewald, C; Garcés, E; Alacid, E; Rossi, S; Camp, J

2013-02-01

The principal fatty acids from the lipid profiles of two autochthonous dinoflagellates (Alexandrium minutum and Karlodinium veneficum) and one raphidophyte (Heterosigma akashiwo) maintained in bubble column photobioreactors under outdoor culture conditions are described for the first time. The biomass production, lipid content and lipid productivity of these three species were determined and the results compared to those obtained when the strains were cultured indoors. Under the latter condition, the biotic values did not significantly differ among species, whereas under outdoor conditions, differences in both duplication time and fatty acids content were observed. Specifically, A. minutum had higher biomass productivity (0.35 g·L⁻¹ day⁻¹), lipid productivity (80.7 mg lipid·L⁻¹ day⁻¹) and lipid concentration (252 mg lipid·L⁻¹) at harvest time (stationary phase) in outdoor conditions. In all three strains, the growth rate and physiological response to the light and temperature fluctuations of outdoor conditions greatly impacted the production parameters. Nonetheless, the species could be successfully grown in an outdoor photobioreactor and were of sufficient robustness to enable the establishment of long-term cultures yielding consistent biomass and lipid production.

Development of the Digestive System-Experimental Challenges and Approaches of Infant Lipid Digestion.

PubMed

Abrahamse, Evan; Minekus, Mans; van Aken, George A; van de Heijning, Bert; Knol, Jan; Bartke, Nana; Oozeer, Raish; van der Beek, Eline M; Ludwig, Thomas

2012-12-01

At least during the first 6 months after birth, the nutrition of infants should ideally consist of human milk which provides 40-60 % of energy from lipids. Beyond energy, human milk also delivers lipids with a specific functionality, such as essential fatty acids (FA), phospholipids, and cholesterol. Healthy development, especially of the nervous and digestive systems, depends fundamentally on these. Epidemiological data suggest that human milk provides unique health benefits during early infancy that extend to long-lasting benefits. Preclinical findings show that qualitative changes in dietary lipids, i.e., lipid structure and FA composition, during early life may contribute to the reported long-term effects. Little is known in this respect about the development of digestive function and the digestion and absorption of lipids by the newborn. This review gives a detailed overview of the distinct functionalities that dietary lipids from human milk and infant formula provide and the profound differences in the physiology and biochemistry of lipid digestion between infants and adults. Fundamental mechanisms of infant lipid digestion can, however, almost exclusively be elucidated in vitro. Experimental approaches and their challenges are reviewed in depth.

Human longevity is associated with regular sleep patterns, maintenance of slow wave sleep, and favorable lipid profile

PubMed Central

Mazzotti, Diego Robles; Guindalini, Camila; Moraes, Walter André dos Santos; Andersen, Monica Levy; Cendoroglo, Maysa Seabra; Ramos, Luiz Roberto; Tufik, Sergio

2014-01-01

Some individuals are able to successfully reach very old ages, reflecting higher adaptation against age-associated effects. Sleep is one of the processes deeply affected by aging; however few studies evaluating sleep in long-lived individuals (aged over 85) have been reported to date. The aim of this study was to characterize the sleep patterns and biochemical profile of oldest old individuals (N = 10, age 85–105 years old) and compare them to young adults (N = 15, age 20–30 years old) and older adults (N = 13, age 60–70 years old). All subjects underwent full-night polysomnography, 1-week of actigraphic recording and peripheral blood collection. Sleep electroencephalogram spectral analysis was also performed. The oldest old individuals showed lower sleep efficiency and REM sleep when compared to the older adults, while stage N3 percentage and delta power were similar across the groups. Oldest old individuals maintained strictly regular sleep-wake schedules and also presented higher HDL-cholesterol and lower triglyceride levels than older adults. The present study revealed novel data regarding specific sleep patterns and maintenance of slow wave sleep in the oldest old group. Taken together with the favorable lipid profile, these results contribute with evidence to the importance of sleep and lipid metabolism regulation in the maintenance of longevity in humans. PMID:25009494

Peripheral Effects of FAAH Deficiency on Fuel and Energy Homeostasis: Role of Dysregulated Lysine Acetylation

PubMed Central

Vaitheesvaran, Bhavapriya; Yang, Li; Hartil, Kirsten; Glaser, Sherrye; Yazulla, Stephen; Bruce, James E.; Kurland, Irwin J.

2012-01-01

Background FAAH (fatty acid amide hydrolase), primarily expressed in the liver, hydrolyzes the endocannabinoids fatty acid ethanolamides (FAA). Human FAAH gene mutations are associated with increased body weight and obesity. In our present study, using targeted metabolite and lipid profiling, and new global acetylome profiling methodologies, we examined the role of the liver on fuel and energy homeostasis in whole body FAAH−/− mice. Methodology/Principal Findings FAAH−/− mice exhibit altered energy homeostasis demonstrated by decreased oxygen consumption (Indirect calorimetry). FAAH−/− mice are hyperinsulinemic and have adipose, skeletal and hepatic insulin resistance as indicated by stable isotope phenotyping (SIPHEN). Fed state skeletal muscle and liver triglyceride levels was increased 2–3 fold, while glycogen was decreased 42% and 57% respectively. Hepatic cholesterol synthesis was decreased 22% in FAAH−/− mice. Dysregulated hepatic FAAH−/− lysine acetylation was consistent with their metabolite profiling. Fasted to fed increases in hepatic FAAH−/− acetyl-CoA (85%, p<0.01) corresponded to similar increases in citrate levels (45%). Altered FAAH−/− mitochondrial malate dehydrogenase (MDH2) acetylation, which can affect the malate aspartate shuttle, was consistent with our observation of a 25% decrease in fed malate and aspartate levels. Decreased fasted but not fed dihydroxyacetone-P and glycerol-3-P levels in FAAH−/− mice was consistent with a compensating contribution from decreased acetylation of fed FAAH−/− aldolase B. Fed FAAH−/− alcohol dehydrogenase (ADH) acetylation was also decreased. Conclusions/Significance Whole body FAAH deletion contributes to a pre-diabetic phenotype by mechanisms resulting in impairment of hepatic glucose and lipid metabolism. FAAH−/− mice had altered hepatic lysine acetylation, the pattern sharing similarities with acetylation changes reported with chronic alcohol treatment. Dysregulated hepatic lysine acetylation seen with impaired FAA hydrolysis could support the liver's role in fostering the pre-diabetic state, and may reflect part of the mechanism underlying the hepatic effects of endocannabinoids in alcoholic liver disease mouse models. PMID:22442717

Determination of lipid bilayer affinities and solvation characteristics by electrokinetic chromatography using polymer-bound lipid bilayer nanodiscs.

PubMed

Penny, William M; Palmer, Christopher P

2018-03-01

Styrene-maleic acid polymer-bound lipid bilayer nanodiscs have been investigated and characterized by electrokinetic chromatography. Linear solvation energy relationship analysis was employed to characterize the changes in solvation environment of nanodiscs of varied belt to lipid ratio, belt polymer chemistry and molecular weight, and lipid composition. Increases in the lipid to belt polymer ratio resulted in smaller, more cohesive nanodiscs with greater electrophoretic mobility. Nanodisc structures with belt polymers of different chemistry and molecular weight were compared and showed only minor changes in solvent characteristics and selectivity consistent with changes in structure of the lipid bilayer. Seven phospholipid and sphingomyelin nanodiscs of different lipid composition were characterized. Changes in lipid head group structure had a significant effect on bilayer-solute interactions. In most cases, changes in alkyl tail structure had no discernible effect on solvation environment aside from those explained by changes in the gel-liquid transition temperature. Comparison to vesicles of similar lipid composition show only minor differences in solvation environment, likely due to differences in lipid composition and bilayer curvature. Together these results provide evidence that the dominant solute-nanodisc interactions are with the lipid bilayer and that head group chemistry has a greater impact on bilayer-solute interactions than alkyl tail or belt polymer structure. Nanodisc electrokinetic chromatography is demonstrated to allow characterization of solute interactions with lipid bilayers of varied composition. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Which Food Patterns Are Predictors of Obesity in Tehranian Adults?

ERIC Educational Resources Information Center

Hosseini-Esfahani, Firoozeh; Djazaieri, Seyed-Abolghasem; Mirmiran, Parvin; Mehrabi, Yadollah; Azizi, Fereidoun

2012-01-01

Objectives: To determine whether changes in food patterns over a period of 6 years were related to obesity in Tehranian adults. Design: Data on dietary intake, using the food frequency questionnaire, and anthropometry were obtained in 2 periods of the survey (1999-2001 and 2005-2007). Setting: Participants of the Tehran Lipid and Glucose Study.…

The Arabidopsis translatome cell-specific mRNA atlas: Mining suberin and cutin lipid monomer biosynthesis genes as an example for data application.

PubMed

Mustroph, Angelika; Bailey-Serres, Julia

2010-03-01

Plants consist of distinct cell types distinguished by position, morphological features and metabolic activities. We recently developed a method to extract cell-type specific mRNA populations by immunopurification of ribosome-associated mRNAs. Microarray profiles of 21 cell-specific mRNA populations from seedling roots and shoots comprise the Arabidopsis Translatome dataset. This gene expression atlas provides a new tool for the study of cell-specific processes. Here we provide an example of how genes involved in a pathway limited to one or few cell-types can be further characterized and new candidate genes can be predicted. Cells of the root endodermis produce suberin as an inner barrier between the cortex and stele, whereas the shoot epidermal cells form cutin as a barrier to the external environment. Both polymers consist of fatty acid derivates, and share biosynthetic origins. We use the Arabidopsis Translatome dataset to demonstrate the significant cell-specific expression patterns of genes involved in those biosynthetic processes and suggest new candidate genes in the biosynthesis of suberin and cutin.

Pretranslational regulation of the synthesis of the third component of complement in human mononuclear phagocytes by the lipid A portion of lipopolysaccharide.

PubMed Central

Strunk, R C; Whitehead, A S; Cole, F S

1985-01-01

The third component of complement (C3) is a plasma glycoprotein with a variety of biologic functions in the initiation and maintenance of host response to infectious agents. While the hepatocyte is the primary source of plasma C3, mononuclear phagocytes contribute to the regulation of tissue availability of C3. Lipopolysaccharide (LPS), a constituent of cell walls of gram-negative bacteria, consists of a polysaccharide moiety (core polysaccharide and O antigen) covalently linked to a lipid portion (lipid A). Using metabolic labeling with [35S]methionine, immunoprecipitation, and SDS-polyacrylamide gel electrophoresis, we examined the effects of LPS on synthesis of C3 by human mononuclear phagocytes as well as synthesis of the second component of complement (C2), factor B, lysozyme, and total protein. LPS increased C3 synthesis 5-30-fold without affecting the kinetics of secretion of C3 or the synthesis of C2, lysozyme, or total protein. Factor B synthesis was consistently increased by LPS. Experiments with lipid A-inactivated LPS (alkaline treated), LPS from a polysaccharide mutant strain, and lipid X (a lipid A precursor) indicated that the lipid A portion is the structural element required for this effect. Northern blot analysis demonstrated at least a fivefold increase in C3 mRNA in LPS-treated monolayers, which suggests that the regulation of the increase in C3 synthesis is pretranslational. C2 mRNA and factor B mRNA were increased approximately twofold. The availability of specific gene products in human mononuclear phagocytes that respond to LPS should permit understanding of the molecular regulation of more complex functions of these cells elicited by LPS in which multiple gene products are coordinately expressed. Images PMID:3900137

Dynamics and stability of lipid bilayers modulated by thermosensitive polypeptides, cholesterols, and PEGylated lipids.

PubMed

Lee, Hwankyu; Kim, Hyun Ryoung; Park, Jae Chan

2014-02-28

Lipid bilayers, which consist of dipalmitoylglycerophosphocholines (DPPCs), PEGylated lipids, cholesterols, and elastin-like polypeptides (ELPs; [VPGVG]3) at different molar ratios, were simulated. Simulations were carried out for 2 μs using the coarse-grained (CG) model that had captured the experimentally observed phase behavior of PEGylated lipids and lateral diffusivity of DPPC bilayers. Starting with the initial position of ELPs on the bilayer surface, ELPs insert into the hydrophobic region of the bilayer because of their interaction with lipid tails, consistent with previous all-atom simulations. Lateral diffusion coefficients of DPPCs significantly increase in the bilayer composed of more ELPs and less cholesterols, showing their opposite effects on the bilayer dynamics. In particular, ELPs modulate the dynamics and phase for the disordered liquid bilayer, but not for the ordered gel bilayer, indicating that ELPs can destabilize only the disordered bilayer. In the ordered bilayer, ELP chains tend to have a spherical shape and slowly diffuse, while they are extended and diffuse faster in the disordered bilayer, indicating the effect of the bilayer phase on the conformation and diffusivity of ELPs. These findings explain the experimental observation that the ELP-conjugated liposomes are stable at 310 K (ordered phase) but become unstable and release the encapsulated drugs at 315 K (disordered phase), which suggests the effects of ELPs and cholesterols. Since the cholesterol-stabilized bilayer can be destabilized by the extended shaped ELPs only in the disordered phase (not in the ordered phase), the inclusion of cholesterols is required to safely shield drugs at 310 K as well as allow ELPs to disrupt lipids and destabilize the liposomes at 315 K.

Divergence of water balance mechanisms and acclimation potential in body color morphs of Drosophila ananassae.

PubMed

Parkash, Ravi; Aggarwal, Dau Dayal; Lambhod, Chanderkala; Singh, Divya

2014-01-01

Drosophila ananassae is a desiccation sensitive species, but the physiological basis of its abundance in the drier subtropical areas is largely unknown. We tested the hypothesis whether body color morphs of D. ananassae differ in the mechanistic basis of water conservation as well as desiccation acclimation potential, consistent with their distribution under dry or wet habitats. We observed reduced rate of water loss consistent with the greater desiccation potential of dark morph as compared with light morph, despite lack of quantitative differences in cuticular lipid mass between them. Dark morph evidenced greater wet and dry mass (∼1.17-fold) as well as higher hemolymph content (∼1.70-fold) and (∼17%) dehydration tolerance to sustain longer survival under desiccation stress (LT50 17.5 hr) as compared with light morph (LT50 4.3 hr). We found significant differences in the storage of energy metabolites in the body color morphs of D. ananassae, that is, carbohydrate content was significantly higher (∼0.18 mg/mg dry mass) in the dark morph as compared to light morph, but greater (∼0.05 mg/mg dry mass) body lipid content was evident in the light morph. Under desiccation stress, dark and light morphs utilized mainly carbohydrates but also lipids to a lesser extent. However, the rate of utilization of energy metabolites did not vary between dark and light morphs. Further, the dark morph consumed higher energy content derived from carbohydrates under desiccation stress as compared with the light morph. Finally, we found contrasting patterns of acclimation to desiccation stress in the two body color morphs, that is, increase in desiccation survival (4.7 hr), as well as in dehydration tolerance (∼6%) due to acclimation of the dark morph but no such effects were observed in the light morph. Thus, divergence in water balance mechanisms as well as acclimation potential reflects evolved physiological adaptations of the dark morph under drier but of the light morph to wet climatic conditions. © 2013 Wiley Periodicals, Inc.

Erythrocyte and plasma fatty acid patterns in dogs with atopic dermatitis and healthy dogs in the same household

PubMed Central

Zimmermann, Annett; Gück, Thomas; Oechtering, Gerhard

2006-01-01

Abstract Recent studies have indicated that dogs with canine atopic dermatitis (CAD) may have a disorder of fatty acid metabolism: possibly low or absent activity of Δ6-desaturase or Δ5-desaturase, or both. To clarify this possibility, we examined the erythrocyte and plasma fatty acid patterns of 8 dogs with CAD and their 8 healthy housemates. Atopic dermatitis was diagnosed according to the criteria proposed by Willemse; other causes of dermatitis were excluded clinically and by appropriate tests. Erythrocyte ghosts were prepared from blood samples. Membrane lipids were extracted and separated by thin-layer chromatography. From plasma and lipid fractions, fatty acid content was determined by gas chromatography. In erythrocytes, but not in plasma, we observed significant differences in the fatty acid pattern that suggested a reduction in the n6 fatty acid products of the Δ6- and Δ5-desaturases in dogs with atopic dermatitis when compared with healthy housemates. PMID:16850941

Lipid Bilayer Vesicles with Numbers of Membrane-Linking Pores

NASA Astrophysics Data System (ADS)

Ken-ichirou Akashi,; Hidetake Miyata,

2010-06-01

We report that phospholipid membranes spontaneously formed in aqueous medium giant unilamellar vesicles (GUVs) possessing many membranous wormhole-like structures (membrane-linking pores, MLPs). By phase contract microscopy and confocal fluorescence microscopy, the structures of the MLPs, consisting of lipid bilayer, were resolvable, and a variety of vesicular shapes having many MLPs (a high genus topology) were found. These vesicles were stable but easily deformed by micromanipulation with a microneedle. We also observed the size reduction of the MLPs with the increase in membrane tension, which was qualitatively consistent with a prediction from a simple dynamical model.

Jumping acoustic bubbles on lipid bilayers.

PubMed

Der Loughian, Christelle; Muleki Seya, Pauline; Pirat, Christophe; Inserra, Claude; Béra, Jean-Christophe; Rieu, Jean-Paul

2015-05-07

In the context of sonoporation, we use supported lipid bilayers as a model for biological membranes and investigate the interactions between the bilayer and microbubbles induced by ultrasound. Among the various types of damage caused by bubbles on the surface, our experiments exhibit a singular dynamic interaction process where bubbles are jumping on the bilayer, forming a necklace pattern of alteration on the membrane. This phenomenon was explored with different time and space resolutions and, based on our observations, we propose a model for a microbubble subjected to the combined action of van der Waals, acoustic and hydrodynamic forces. Describing the repeated jumps of the bubble, this model explains the lipid exchanges between the bubble and bilayer.

Aliphatic Chains of Esterified Lipids in Isolated Eyespots of Euglena gracilis var. bacillaris1

PubMed Central

Hilenski, Lula L.; Walne, Patricia L.; Snyder, Fred

1976-01-01

Isolated eyespot granules of Euglena gracilis Klebs var. bacillaris Pringsheim contained approximately 6% lipids (based on protein). Separation of the lipid extracts by thin layer chromatography revealed four major fractions: wax esters, triacylglycerols, free fatty acids, and phospholipids. Methanolysis of each fraction yielded between 27 and 29 different fatty acids ranging from 12:0 to 22:6. Acetates of the fatty alcohols of the wax fraction consisted of 11:0 to 18:0 carbon chains, with 14:0 being the major component; unsaturated alcohols were not detected. PMID:16659543

Solid-state fermentation of Mortierella isabellina for lipid production from soybean hull.

PubMed

Zhang, Jianguo; Hu, Bo

2012-02-01

Soybean hull, generated from soybean processing, is a lignocellulosic material with limited industrial applications and little market value. This research is exploring a new application of soybean hull to be converted to fungal lipids for biodiesel production through solid-state fermentation. Mortierella isabellina was selected as the oil producer because of its high lipid content at low C/N ratio. Several cultivation factors were investigated, including moisture content, inoculums size, fungal spore age, and nutrient supplements, in an attempt to enhance the lipid production of the solid-state fermentation process. The results showed that lipid production with the increase of the moisture content and the spore age, while decreased as the size of inoculums increased. Nutrients addition (KH₂PO₄ 1.2 mg and MgSO₄ 0.6 mg/g soybean hull) improved the lipid production. The total final lipid reached 47.9 mg lipid from 1 g soybean hull after the conversion, 3.3-fold higher than initial lipid reserve in the soybean hull. The fatty acid profile analysis indicated that fatty acid content consisted of 30.0% of total lipid, and 80.4% of total fatty acid was C16 and C18. Therefore, lipid production from soybean hull is a possible option to enable soybean hull as a new resource for biodiesel production and to enhance the overall oil production from soybeans.

Targeted delivery of 10-hydroxycamptothecin to human breast cancers by cyclic RGD-modified lipid-polymer hybrid nanoparticles.

PubMed

Yang, Zhe; Luo, Xingen; Zhang, Xiaofang; Liu, Jie; Jiang, Qing

2013-04-01

Lipid-polymer hybrid nanoparticles (NPs) combining the positive attributes of both liposomes and polymeric NPs are increasingly being considered as promising candidates to carry therapeutic agents safely and efficiently into targeted sites. Herein, a modified emulsification technique was developed and optimized for the targeting lipid-polymer hybrid NPs fabrication; the surface properties and stability of the hybrid NPs were systematically investigated, which confirmed that the hybrid NPs consisted of a poly (lactide-co-glycolide) core with ∼90% surface coverage of the lipid monolayer and a ∼4.4 nm hydrated polyethylene glycol (PEG) shell. Optimization results showed that the lipid:polymer mass ratio and the lipid-PEG:lipid molar ratio could affect the size, lipid association efficiency and stability of hybrid NPs. Furthermore, a model chemotherapy drug, 10-hydroxycamptothecin, was encapsulated into hybrid NPs with a higher drug loading compared to PLGA NPs. Surface modification of the lipid layer and the PEG conjugated targeting ligand did not affect their drug release kinetics. Finally, the cytotoxicity and cellular uptake studies indicated that the lipid coverage and the c(RGDyk) conjugation of the hybrid NPs gained a significantly enhanced ability of cell killing and endocytosis. Our results suggested that lipid-polymer hybrid NPs prepared by the modified emulsion technique have great potential to be utilized as an engineered drug delivery system with precise control ability of surface targeting modification.

Correlation of plasma and peritoneal diasylate clomipramine concentration with hemodynamic recovery after intralipid infusion in rabbits.

PubMed

Harvey, Martyn; Cave, Grant; Hoggett, Kerry

2009-02-01

Drug sequestration to an expanded plasma lipid phase has been proposed as a potential mechanism of action for lipid emulsions in lipophilic cardiotoxin overdose. The authors set out to document plasma and peritoneal diasylate clomipramine concentration after resuscitation with lipid emulsion in a rabbit model of clomipramine-induced hypotension. Twenty sedated mechanically ventilated New Zealand White rabbits were allocated to receive either 12 mL/kg 20% Intralipid or 12 mL/kg saline solution, following clomipramine infusion to 50% baseline mean arterial pressure (MAP). Hemodynamic parameters and serum clomipramine concentration were determined to 59 minutes. Peritoneal dialysis with 20% Intralipid or saline solution was evaluated for clomipramine concentration. Mean arterial pressure was greater in lipid-treated animals as assessed by repeated-measures analysis of variance (F[1,14] = 6.84; p = 0.020). Lipid infusion was associated with elevated plasma clomipramine concentration and reduced initial volume of distribution (Vd; 5.7 [+/-1.6] L/kg lipid vs. 15.9 [+/-7.2] L/kg saline; p = 0.0001). Peritoneal diasylate clomipramine concentration was greater in lipid-treated animals (366.2 [+/-186.2] microg/L lipid vs. 37.7 [+/-13.8] microg/L saline; p = 0.002). Amelioration of clomipramine-induced hypotension with lipid infusion is associated with reduced initial Vd and elevated plasma clomipramine concentration consistent with intravascular drug-lipid sequestration. Concomitant peritoneal dialysis with lipid emulsion enhances clomipramine extraction.

Spatial analysis of lipid metabolites and expressed genes reveals tissue-specific heterogeneity of lipid metabolism in high- and low-oil Brassica napus L. seeds.

PubMed

Lu, Shaoping; Sturtevant, Drew; Aziz, Mina; Jin, Cheng; Li, Qing; Chapman, Kent D; Guo, Liang

2018-06-01

Despite the importance of oilseeds to worldwide human nutrition, and more recently to the production of bio-based diesel fuels, the detailed mechanisms regulating seed oil biosynthesis remain only partly understood, especially from a tissue-specific perspective. Here, we investigated the spatial distributions of lipid metabolites and transcripts involved in oil biosynthesis from seeds of two low-erucic acid genotypes of Brassica napus with high and low seed-oil content. Integrated results from matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) of lipids in situ, lipidome profiling of extracts from seed tissues, and tissue-specific transcriptome analysis revealed complex spatial distribution patterns of lipids and transcripts. In general, it appeared that many triacylglycerol and phosphatidylcholine species distributed heterogeneously throughout the embryos. Tissue-specific transcriptome analysis identified key genes involved in de novo fatty acid biosynthesis in plastid, triacylglycerols assembly and lipid droplet packaging in the endoplasmic reticulum (ER) that may contribute to the high or low oil phenotype and heterogeneity of lipid distribution. Our results imply that transcriptional regulation represents an important means of impacting lipid compartmentalization in oil seeds. While much information remains to be learned about the intricacies of seed oil accumulation and distribution, these studies highlight the advances that come from evaluating lipid metabolism within a spatial context and with multiple omics level datasets. © 2018 The Authors The Plant Journal © 2018 John Wiley & Sons Ltd.

Mutual anti-oxidative effect of gossypol acetic acid and gossypol-iron complex on hepatic lipid peroxidation in male rats.

PubMed

El-Sharaky, A S; Wahby, M M; Bader El-Dein, M M; Fawzy, R A; El-Shahawy, I N

2009-11-01

Gossypol displays anticancer behavior and anti-fertility in males. Male rats were treated with either gossypol acetic acid (GAA) or gossypol-iron complex (GIC). Serum alanine transaminase (ALT) activity elevated of GAA. However, GIC-treated animals showed a decrease in hepatic glutathione (GSH) content with increased malondialdehyde (MDA) content. Whereas, GSH-Px specific activity increased in GAA group. GAA and GIC induce significant increases in the hepatic NEFA with remarkable decrease in the total saturated fatty acids with a significant increase of PUFA. Lipid peroxidation is inhibited by gossypol, which shield lipids against oxidative damage. Phenols are oxidized to phenoxy radicals, which do not permit anti-oxidation due to resonance stabilization. GAA stimulate hydroxyl radicals (()OH) generation and DNA damage. GAA and GIC produce increase in lipid peroxidation as proved by a steep rise in thiobarbituric acid reactive species (TBARS). Controversy of specificity of TBARS towards compounds other than MDA was reported. If TBARS increased, more specific assay to be employed. Assay of lipid classes and fatty acids pattern, reveled the significance of the technique in assessment of lipid peroxidation in tissues. GAA and GIC were powerful inhibitors of lipid peroxidation and exhibit pro- and antioxidant behavior, with less toxicity of GIC.

The juxtamembrane regions of human receptor tyrosine kinases exhibit conserved interaction sites with anionic lipids

PubMed Central

Hedger, George; Sansom, Mark S. P.; Koldsø, Heidi

2015-01-01

Receptor tyrosine kinases (RTKs) play a critical role in diverse cellular processes and their activity is regulated by lipids in the surrounding membrane, including PIP2 (phosphatidylinositol-4,5-bisphosphate) in the inner leaflet, and GM3 (monosialodihexosylganglioside) in the outer leaflet. However, the precise details of the interactions at the molecular level remain to be fully characterised. Using a multiscale molecular dynamics simulation approach, we comprehensively characterise anionic lipid interactions with all 58 known human RTKs. Our results demonstrate that the juxtamembrane (JM) regions of RTKs are critical for inducing clustering of anionic lipids, including PIP2, both in simple asymmetric bilayers, and in more complex mixed membranes. Clustering is predominantly driven by interactions between a conserved cluster of basic residues within the first five positions of the JM region, and negatively charged lipid headgroups. This highlights a conserved interaction pattern shared across the human RTK family. In particular predominantly the N-terminal residues of the JM region are involved in the interactions with PIP2, whilst residues within the distal JM region exhibit comparatively less lipid specificity. Our results suggest that JM–lipid interactions play a key role in RTK structure and function, and more generally in the nanoscale organisation of receptor-containing cell membranes. PMID:25779975

Occurrence and distribution of extractable and non-extractable GDGTs in podzols: implications for the reconstruction of mean air temperature

NASA Astrophysics Data System (ADS)

Huguet, Arnaud; Fosse, Céline; Metzger, Pierre; Derenne, Sylvie

2010-05-01

Glycerol dialkyl glycerol tetraethers (GDGTs) are complex lipids of high molecular weight, present in cell membranes of archaea and some bacteria. Archaeal membranes are formed predominantly by isoprenoid GDGTs with acyclic or ring-containing biphytanyl chains. Another type of GDGTs with branched instead of isoprenoid alkyl chains was recently discovered in soils. Branched tetraethers were suggested to be produced by anaerobic bacteria and can be used to reconstruct past air temperature and soil pH. Lipids preserved in soils can take two broad chemical forms: extractable lipids, recoverable upon solvent extraction, and non-extractable lipids, linked to the organic or mineral matrix of soils. Moreover, within the extractable pool, core (i.e. "free") lipids and intact polar (i.e. "bound") lipids can be distinguished. These three lipid fractions may respond to environmental changes in different ways and the information derived from these three pools may differ. The aim of the present work was therefore to compare the abundance and distribution of the three GDGT pools in two contrasted podzols: a temperate podzol located 40 km north of Paris and a tropical podzol from the upper Amazon Basin. Five samples were collected from the whole profile of the temperate podzol including the litter layer. Five additional samples were obtained from three profiles of the tropical soil sequence, representative of the transition between a latosol and a well-developed podzol. Vertical and/or lateral variations in GDGT content and composition were highlighted. In particular, in the tropical sequence, GDGTs were present at relatively low concentrations in the early stages of podzolisation and were more abundant in the well-developed podzolic horizons, where higher acidity and increased bacterial activity may favour their stabilization. Concerning the temperate podzol, GDGT distribution was shown to vary greatly with depth in the soil profile, the methylation degree of bacterial GDGTs being notably higher in the surficial than in the deep soil horizons. Bacterial GDGTs were also detected in the litter layer of the temperate podzol, suggesting the presence of branched-GDGT producing bacteria in the litter, probably in anoxic microenvironments. Last, we showed for the first time that substantial amounts of non-extractable GDGTs could be released after acid hydrolysis of solvent-extracted soils, since non-extractable lipids represented in average ca. 25% of total (i.e. extractable + non-extractable) bacterial GDGTs and ca. 30% of total archaeal GDGTs in podzol samples. In addition, we observed that extractable and non-extractable GDGTs could present different distribution patterns. Thus, the average methylation degree of bacterial GDGTs was higher in the extractable than in the non-extractable lipid fraction in three soil horizons of the temperate podzol. Consequently, different mean air temperature values could be derived from extractable and non-extractable bacterial GDGT distributions, suggesting that data obtained from the extractable lipid fraction have to be interpreted with care. MAT values derived from non-extractable GDGTs were shown to be more consistent with MAT records, implying that MAT estimates obtained from the non-extractable pool might be more reliable.

Absorption Study of Genistein Using Solid Lipid Microparticles and Nanoparticles: Control of Oral Bioavailability by Particle Sizes.

PubMed

Kim, Jeong Tae; Barua, Sonia; Kim, Hyeongmin; Hong, Seong-Chul; Yoo, Seung-Yup; Jeon, Hyojin; Cho, Yeongjin; Gil, Sangwon; Oh, Kyungsoo; Lee, Jaehwi

2017-07-01

In this study, the effect of particle size of genistein-loaded solid lipid particulate systems on drug dissolution behavior and oral bioavailability was investigated. Genistein-loaded solid lipid microparticles and nanoparticles were prepared with glyceryl palmitostearate. Except for the particle size, other properties of genistein-loaded solid lipid microparticles and nanoparticles such as particle composition and drug loading efficiency and amount were similarly controlled to mainly evaluate the effect of different particle sizes of the solid lipid particulate systems on drug dissolution behavior and oral bioavailability. The results showed that genistein-loaded solid lipid microparticles and nanoparticles exhibited a considerably increased drug dissolution rate compared to that of genistein bulk powder and suspension. The microparticles gradually released genistein as a function of time while the nanoparticles exhibited a biphasic drug release pattern, showing an initial burst drug release, followed by a sustained release. The oral bioavailability of genistein loaded in solid lipid microparticles and nanoparticles in rats was also significantly enhanced compared to that in bulk powders and the suspension. However, the bioavailability from the microparticles increased more than that from the nanoparticles mainly because the rapid drug dissolution rate and rapid absorption of genistein because of the large surface area of the genistein-solid lipid nanoparticles cleared the drug to a greater extent than the genistein-solid lipid microparticles did. Therefore, the findings of this study suggest that controlling the particle size of solid-lipid particulate systems at a micro-scale would be a promising strategy to increase the oral bioavailability of genistein.

Diterpenoid compounds and other lipids in deep-sea sediments and their geochemical significance

NASA Technical Reports Server (NTRS)

Simoneit, B. R. T.

1977-01-01

Cyclic diterpenoid compounds have been found by various investigators in the geosphere (e.g., fossil resins, coals, soil, shale, and deep-sea sediments). These compounds occur in significant amounts only in higher plants and are therefore potential markers of terrigenous plant lipids. Diterpenoids with the abietane skeleton (mainly dehydroabietic acid) have been identified in the lipids of sediment samples from the northeast Pacific Ocean, Black Sea, and North Atlantic Ocean. The presence of these resin-derived compounds was correlated with the terrigenous clay components and with the presence of pollen. The presence of polycyclic diterpenoids was also correlated with the distribution patterns and inferred sources of other sediment lipid constituents. Potamic transport, followed by turbidite redistribution, is the probable input mechanism of these resin-derived compounds to the deep-sea sediments. These diterpenoids appear to be excellent biological markers of resinous higher plants.

Retention behavior of lipids in reversed-phase ultrahigh-performance liquid chromatography-electrospray ionization mass spectrometry.

PubMed

Ovčačíková, Magdaléna; Lísa, Miroslav; Cífková, Eva; Holčapek, Michal

2016-06-10

Reversed-phase ultrahigh-performance liquid chromatography (RP-UHPLC) method using two 15cm sub-2μm particles octadecylsilica gel columns is developed with the goal to separate and unambiguously identify a large number of lipid species in biological samples. The identification is performed by the coupling with high-resolution tandem mass spectrometry (MS/MS) using quadrupole - time-of-flight (QTOF) instrument. Electrospray ionization (ESI) full scan and tandem mass spectra are measured in both polarity modes with the mass accuracy better than 5ppm, which provides a high confidence of lipid identification. Over 400 lipid species covering 14 polar and nonpolar lipid classes from 5 lipid categories are identified in total lipid extracts of human plasma, human urine and porcine brain. The general dependences of relative retention times on relative carbon number or relative double bond number are constructed and fit with the second degree polynomial regression. The regular retention patterns in homologous lipid series provide additional identification point for UHPLC/MS lipidomic analysis, which increases the confidence of lipid identification. The reprocessing of previously published data by our and other groups measured in the RP mode and ultrahigh-performance supercritical fluid chromatography on the silica column shows more generic applicability of the polynomial regression for the description of retention behavior and the prediction of retention times. The novelty of this work is the characterization of general trends in the retention behavior of lipids within logical series with constant fatty acyl length or double bond number, which may be used as an additional criterion to increase the confidence of lipid identification. Copyright © 2016 Elsevier B.V. All rights reserved.

Adsorption of lysozyme to phospholipid and meibomian lipid monolayer films.

PubMed

Mudgil, Poonam; Torres, Margaux; Millar, Thomas J

2006-03-15

It is believed that a lipid layer forms the outer layer of the pre-ocular tear film and this layer helps maintain tear film stability by lowering its surface tension. Proteins of the aqueous layer of the tear film (beneath the lipid layer) may also contribute to reducing surface tension by adsorbing to, or penetrating the lipid layer. The purpose of this study was to compare the penetration of lysozyme, a tear protein, into films of meibomian lipids and phospholipids held at different surface pressures to determine if lysozyme were part of the surface layer of the tear film. Films of meibomian lipids or phospholipids were spread onto the surface of a buffered aqueous subphase. Films were compressed to particular pressures and lysozyme was injected into the subphase. Changes in surface pressure were monitored to determine adsorption or penetration of lysozyme into the surface film. Lysozyme penetrated a meibomian lipid film at all pressures tested (max=20 mN/m). It also penetrated phosphatidylglycerol, phosphatidylserine or phosphatidylethanolamine lipid films up to a pressure of 20 mN/m. It was not able to penetrate a phosphatidylcholine film at pressures >or=10 mN/m irrespective of the temperature being at 20 or 37 degrees C. However, it was able to penetrate it at very low pressures (<10 mN/m). Epifluorescence microscopy showed that the protein either adsorbs to or penetrates the lipid layer and the pattern of mixing depended upon the lipid at the surface. These results indicate that lysozyme is present at the surface of the tear film where it contributes to decreasing the surface tension by adsorbing and penetrating the meibomian lipids. Thus it helps to stabilize the tear film.

Ratiometric imaging of gastrodermal lipid bodies in coral-dinoflagellate endosymbiosis

NASA Astrophysics Data System (ADS)

Luo, Y.-J.; Wang, L.-H.; Chen, W.-N. U.; Peng, S.-E.; Tzen, J. T.-C.; Hsiao, Y.-Y.; Huang, H.-J.; Fang, L.-S.; Chen, C.-S.

2009-03-01

Cnidaria-dinoflagellate endosymbiosis is the phenomenon of autotrophic symbionts living inside the gastrodermal cells of their animal hosts. The molecular mechanism that regulates this association remains unclear. Using quantitative microscopy, we now provide evidence that the dynamic lipid changes in gastrodermal “lipid bodies” (LBs) reflect the symbiotic status of the host cell and its symbiont in the hermatypic coral Euphyllia glabrescens. By dual-emission ratiometric imaging with a solvatochromic fluorescent probe, Nile red (9-diethylamino-5H-benzo[α]phenoxazine-5-one), we showed that the in situ distribution of polar versus neutral lipids in LBs in living gastrodermal cells and symbionts can be analyzed. The ratio of Nile red fluorescence at red (R) versus green (G) wavelength region (i.e., R/G ratio) correlated with the relative molar ratio of polar (P) versus neutral (NP) lipids (i.e., P/NP ratio). The R/G ratio in host LBs increased after bleaching, indicating a decrease in neutral lipid accumulation in gastrodermal cells. On the other hand, neutral lipid accumulation inside the symbiont LBs resulted in gradual decreases of the R/G ratio as a result of bleaching. In comparison with the bleaching event, there was no relative lipid concentration change in host LBs under continual light or dark treatments as shown by insignificant R/G ratio shift. Patterns of R/G ratio shift in symbiont LBs were also different between corals undergoing bleaching and continual light/dark treatment. In the latter, there was little lipid accumulation in symbionts, with no resulting R/G ratio decrease. These results, demonstrating that the symbiotic status positively correlated with morphological and compositional changes of lipid bodies, not only highlight the pivotal role of LBs, but also implicate an involvement of lipid trafficking in regulating the endosymbiosis.

A Caveolin Dominant Negative Mutant Associates with Lipid Bodies and Induces Intracellular Cholesterol Imbalance

PubMed Central

Pol, Albert; Luetterforst, Robert; Lindsay, Margaret; Heino, Sanna; Ikonen, Elina; Parton, Robert G.

2001-01-01

Recent studies have indicated a role for caveolin in regulating cholesterol-dependent signaling events. In the present study we have analyzed the role of caveolins in intracellular cholesterol cycling using a dominant negative caveolin mutant. The mutant caveolin protein, cav-3DGV, specifically associates with the membrane surrounding large lipid droplets. These structures contain neutral lipids, and are accessed by caveolin 1–3 upon overexpression. Fluorescence, electron, and video microscopy observations are consistent with formation of the membrane-enclosed lipid rich structures by maturation of subdomains of the ER. The caveolin mutant causes the intracellular accumulation of free cholesterol (FC) in late endosomes, a decrease in surface cholesterol and a decrease in cholesterol efflux and synthesis. The amphiphile U18666A acts synergistically with cavDGV to increase intracellular accumulation of FC. Incubation of cells with oleic acid induces a significant accumulation of full-length caveolins in the enlarged lipid droplets. We conclude that caveolin can associate with the membrane surrounding lipid droplets and is a key component involved in intracellular cholesterol balance and lipid transport in fibroblasts. PMID:11238460

Lipid composition of positively buoyant eggs of reef building corals

NASA Astrophysics Data System (ADS)

Arai, Iakayuki; Kato, Misako; Heyward, Andrew; Ikeda, Yutaka; Iizuka, Tokio; Maruyama, Tadashi

1993-07-01

Lipid composition of the eggs of three reef building corals, Acropora millepora, A. tenuis and Montipora digitata, were determined. Sixty to 70% of the egg dry weight was lipid, which consisted of wax esters (69.5 81.8%), triacylglycerols (1.1 8.4%) and polar lipids c/mainly phospholipids (11.9 13.2%). Montipora digitata also contained some polar lipids typical of the thylakoid membrane in chloroplasts, probably due to the presence of symbiotic zooxanthellae in the eggs. The wax esters appeared to be the major contributor to positive buoyancy of the eggs, and specific gravity of wax esters in A. millepora was estimated to be 0.92. Among the fatty acids of the wax esters, 34.9 51.3% was hexadecanoic acid (16:0) while the major fatty acids in polar lipids were octadecenoic acid (18:1), hexadecanoic acid (16:0), eicosapentaenoic acid (20:5) and eicosatetraenoic acid (20:4). The wax ester appears to be the main component of the 4.5 6.0 μm diameter lipid droplets which fill most of the central mass of the coral eggs.

Time-Correlated Single-Photon Counting Fluorescence Imaging of Lipid Domains In Raft-Mimicking Giant Unilamellar Vesicles

NASA Astrophysics Data System (ADS)

Clarke, James; Cheng, Kwan; Shindell, Orrin; Wang, Exing

We have designed and constructed a high-throughput electrofusion chamber and an incubator to fabricate Giant Unilamellar Vesicles (GUVs) consisting of high-melting lipids, low-melting lipids, cholesterol and both ordered and disordered phase sensitive fluorescent probes (DiIC12, dehydroergosterol and BODIPY-Cholesterol). GUVs were formed in a 3 stage pulse sequence electrofusion process with voltages ranging from 50mVpp to 2.2Vpp and frequencies from 5Hz to 10Hz. Steady state and time-correlated single-photon counting (TCSPC) fluorescence lifetime (FLIM) based confocal and/or multi-photon microscopic techniques were used to characterize phase separated lipid domains in GUVs. Confocal imaging measures the probe concentration and the chemical environment of the system. TCSPC techniques determine the chemical environment through the perturbation of fluorescent lifetimes of the probes in the system. The above techniques will be applied to investigate the protein-lipid interactions involving domain formation. Specifically, the mechanisms governing lipid domain formations in the above systems that mimic the lipid rafts in cells will be explored. Murchison Fellowship at Trinity University.

National Lipid Association Annual Summary of Clinical Lipidology 2015.

PubMed

Bays, Harold E; Jones, Peter H; Brown, W Virgil; Jacobson, Terry A

2014-01-01

The National Lipid Association (NLA) Annual Summary of Clinical Lipidology 2015 is a summary of principles important to the patient-centered evaluation, management, and care of patients with dyslipidemia. This summary is intended to be a "living document," with future annual updates based on emerging science, clinical considerations, and new NLA Position and Consensus Statements. The goal is to provide clinicians an ongoing resource that translates the latest advances in medical science toward the evaluation and treatment of patients with dyslipidemia. The 2015 NLA Annual Summary of Clinical Lipidology was founded on the principles of evidence-based medicine and is generally consistent with established national and international lipid guidelines. Topics include a general discussion of the 2014 NLA Recommendations for Patient-Centered Management of Dyslipidemia, genetics, secondary causes of dyslipidemia, biomarkers and "advanced lipid testing," medical nutrition, physical activity, obesity, pharmacotherapy, statin safety, lipid-altering drug interactions, lipoprotein apheresis, dyslipidemia in children and adolescence, dyslipidemia in older individuals, race/ethnicity, and women, health information technology and electronic medical records, as well as investigational lipid-altering drugs in development. Copyright © 2014 National Lipid Association. All rights reserved.

Template-based combinatorial enumeration of virtual compound libraries for lipids

PubMed Central

2012-01-01

A variety of software packages are available for the combinatorial enumeration of virtual libraries for small molecules, starting from specifications of core scaffolds with attachments points and lists of R-groups as SMILES or SD files. Although SD files include atomic coordinates for core scaffolds and R-groups, it is not possible to control 2-dimensional (2D) layout of the enumerated structures generated for virtual compound libraries because different packages generate different 2D representations for the same structure. We have developed a software package called LipidMapsTools for the template-based combinatorial enumeration of virtual compound libraries for lipids. Virtual libraries are enumerated for the specified lipid abbreviations using matching lists of pre-defined templates and chain abbreviations, instead of core scaffolds and lists of R-groups provided by the user. 2D structures of the enumerated lipids are drawn in a specific and consistent fashion adhering to the framework for representing lipid structures proposed by the LIPID MAPS consortium. LipidMapsTools is lightweight, relatively fast and contains no external dependencies. It is an open source package and freely available under the terms of the modified BSD license. PMID:23006594

The Effect of Valinomycin on the Electrical Properties of Solutions of Red Cell Lipids in n-Decane

PubMed Central

Andreoli, Thomas E.; Tosteson, Daniel C.

1971-01-01

This paper reports the electrical properties of thick lipid membranes in the absence and presence of valinomycin. The thick lipid membranes were formed by placing a solution of sheep red cell lipids in decane between two cellophane partitions which formed the interfaces between the membrane and the two aqueous bathing solutions. The DC electrical resistance of these structures was found to be directly proportional to the reciprocal of the concentration of lipids in the decane (CL). The limiting resistance, as (CL -1) approached zero, was 3 x 108 ohm-cm2. Resistance was also found to be linearly related to membrane thickness. The limiting resistance at zero thickness was again 1–3 x 108 ohm-cm2. These data are interpreted to indicate that the DC resistance of thick lipid membranes comprises two surface resistances (RS) at each interface with the aqueous bathing solutions, and a bulk resistance (RB) of the lipid-decane solution, arranged in series. Measurements of the effect of variations of area on resistance were consistent with this interpretation. Valinomycin reduced RS but had no effect on RB. Under certain conditions, thick lipid membranes containing valinomycin behaved like highly selective K+ electrodes. PMID:5553100

Tributyltin promoted hepatic steatosis in zebrafish (Danio rerio) and the molecular pathogenesis involved.

PubMed

Zhang, Jiliang; Sun, Ping; Kong, Tao; Yang, Fan; Guan, Wenchao

2016-01-01

Endocrine disruptor effects of tributyltin (TBT) are well established in fish. However, the adverse effects on lipid metabolism are less well understood. Since the liver is the predominant site of de novo synthesis of lipids, the present study uses zebrafish (Danio rerio) to examine lipid accumulation in the livers and hepatic gene expression associated with lipid metabolism pathways. After exposure for 90 days, we found that the livers in fish exposed to TBT were yellowish in appearance and with accumulation of lipid droplet, which is consistent with the specific pathological features of steatosis. Molecular analysis revealed that TBT induced hepatic steatosis by increasing the gene expression associated with lipid transport, lipid storage, lipiogenic enzymes and lipiogenic factors in the livers. Moreover, TBT enhanced hepatic caspase-3 activity and up-regulated genes related to apoptosis and cell-death, which indicated steatotic livers of fish exposed to TBT and the subsequent liver damage were likely due to accelerated hepatocyte apoptosis or cell stress. In short, TBT can produce multiple and complex alterations in transcriptional activity of lipid metabolism and cell damage, which provides potential molecular evidence of TBT on hepatic steatosis. Copyright © 2015 Elsevier B.V. All rights reserved.

Template-based combinatorial enumeration of virtual compound libraries for lipids.

PubMed

Sud, Manish; Fahy, Eoin; Subramaniam, Shankar

2012-09-25

A variety of software packages are available for the combinatorial enumeration of virtual libraries for small molecules, starting from specifications of core scaffolds with attachments points and lists of R-groups as SMILES or SD files. Although SD files include atomic coordinates for core scaffolds and R-groups, it is not possible to control 2-dimensional (2D) layout of the enumerated structures generated for virtual compound libraries because different packages generate different 2D representations for the same structure. We have developed a software package called LipidMapsTools for the template-based combinatorial enumeration of virtual compound libraries for lipids. Virtual libraries are enumerated for the specified lipid abbreviations using matching lists of pre-defined templates and chain abbreviations, instead of core scaffolds and lists of R-groups provided by the user. 2D structures of the enumerated lipids are drawn in a specific and consistent fashion adhering to the framework for representing lipid structures proposed by the LIPID MAPS consortium. LipidMapsTools is lightweight, relatively fast and contains no external dependencies. It is an open source package and freely available under the terms of the modified BSD license.

Noninvasive imaging of intracellular lipid metabolism in macrophages by Raman microscopy in combination with stable isotopic labeling.

PubMed

Matthäus, Christian; Krafft, Christoph; Dietzek, Benjamin; Brehm, Bernhard R; Lorkowski, Stefan; Popp, Jürgen

2012-10-16

Monocyte-derived macrophages play a key role in atherogenesis because their transformation into foam cells is responsible for deposition of lipids in plaques within arterial walls. The appearance of cytosolic lipid droplets is a hallmark of macrophage foam cell formation, and the molecular basics involved in this process are not well understood. Of particular interest is the intracellular fate of different individual lipid species, such as fatty acids or cholesterol. Here, we utilize Raman microscopy to image the metabolism of such lipids and to trace their subsequent storage patterns. The combination of microscopic information with Raman spectroscopy provides a powerful molecular imaging method, which allows visualization at the diffraction limit of the employed laser light and biochemical characterization through associated spectral information. In order to distinguish the molecules of interest from other naturally occurring lipids spectroscopically, deuterium labels were introduced. Intracellular distribution and metabolic changes were observed for serum albumin-complexed palmitic and oleic acid and cholesterol and quantitatively evaluated by monitoring the increase in CD scattering intensities at 0.5, 1, 3, 6, 24, 30, and 36 h. This approach may also allow for investigating the cellular trafficking of other molecules, such as nutrients, metabolites, and drugs.

Subchronic effects of valproic acid on gene expression profiles for lipid metabolism in mouse liver

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Min-Ho; Kim, Mingoo; Lee, Byung-Hoon

2008-02-01

Valproic acid (VPA) is used clinically to treat epilepsy, however it induces hepatotoxicity such as microvesicular steatosis. Acute hepatotoxicity of VPA has been well documented by biochemical studies and microarray analysis, but little is known about the chronic effects of VPA in the liver. In the present investigation, we profiled gene expression patterns in the mouse liver after subchronic treatment with VPA. VPA was administered orally at a dose of 100 mg/kg/day or 500 mg/kg/day to ICR mice, and the livers were obtained after 1, 2, or 4 weeks. The activities of serum liver enzymes did not change, whereas triglyceridemore » concentration increased significantly. Microarray analysis revealed that 1325 genes of a set of 32,996 individual genes were VPA responsive when examined by two-way ANOVA (P < 0.05) and fold change (> 1.5). Consistent with our previous results obtained using an acute VPA exposure model (Lee et al., Toxicol Appl Pharmacol. 220:45-59, 2007), the most significantly over-represented biological terms for these genes included lipid, fatty acid, and steroid metabolism. Biological pathway analysis suggests that the genes responsible for increased biosynthesis of cholesterol and triglyceride, and for decreased fatty acid {beta}-oxidation contribute to the abnormalities in lipid metabolism induced by subchronic VPA treatment. A comparison of the VPA-responsive genes in the acute and subchronic models extracted 15 commonly altered genes, such as Cyp4a14 and Adpn, which may have predictive power to distinguish the mode of action of hepatotoxicants. Our data provide a better understanding of the molecular mechanisms of VPA-induced hepatotoxicity and useful information to predict steatogenic hepatotoxicity.« less

Nutritional physiology of life-history trade-offs: how food protein-carbohydrate content influences life-history traits in the wing-polymorphic cricket Gryllus firmus.

PubMed

Clark, Rebecca M; Zera, Anthony J; Behmer, Spencer T

2015-01-15

Although life-history trade-offs result from the differential acquisition and allocation of nutritional resources to competing physiological functions, many aspects of this topic remain poorly understood. Wing-polymorphic insects, which possess alternative morphs that trade off allocation to flight capability versus early reproduction, provide a good model system for exploring this topic. In this study, we used the wing-polymorphic cricket Gryllus firmus to test how expression of the flight capability versus reproduction trade-off was modified across a heterogeneous protein-carbohydrate nutritional landscape. Newly molted adult female long- and short-winged crickets were given one of 13 diets with different concentrations and ratios of protein and digestible carbohydrate; for each cricket, we measured consumption patterns, growth and allocation to reproduction (ovary mass) versus flight muscle maintenance (flight muscle mass and somatic lipid stores). Feeding responses in both morphs were influenced more by total macronutrient concentration than by protein-carbohydrate ratio, except at high-macronutrient concentration, where protein-carbohydrate balance was important. Mass gain tended to be greatest on protein-biased diets for both morphs, but was consistently lower across all diets for long-winged females. When long-winged females were fed high-carbohydrate foods, they accumulated greater somatic lipid stores; on high-protein foods, they accumulated greater somatic protein stores. Food protein-carbohydrate content also affected short-winged females (selected for early reproductive onset), which showed dramatic increases in ovary size, including ovarian stores of lipid and protein, on protein-biased foods. This is the first study to show how the concentration and ratio of dietary protein and carbohydrate affects consumption and allocation to key physiological features associated with the reproduction-dispersal life-history trade-off. © 2015. Published by The Company of Biologists Ltd.

Effect of the difference in vehicles on gene expression in the rat liver--analysis of the control data in the Toxicogenomics Project Database.

PubMed

Takashima, Kayoko; Mizukawa, Yumiko; Morishita, Katsumi; Okuyama, Manabu; Kasahara, Toshihiko; Toritsuka, Naoki; Miyagishima, Toshikazu; Nagao, Taku; Urushidani, Tetsuro

2006-05-08

The Toxicogenomics Project is a 5-year collaborative project by the Japanese government and pharmaceutical companies in 2002. Its aim is to construct a large-scale toxicology database of 150 compounds orally administered to rats. The test consists of a single administration test (3, 6, 9 and 24 h) and a repeated administration test (3, 7, 14 and 28 days), and the conventional toxicology data together with the gene expression data in liver as analyzed by using Affymetrix GeneChip are being accumulated. In the project, either methylcellulose or corn oil is employed as vehicle. We examined whether the vehicle itself affects the analysis of gene expression and found that corn oil alone affected the food consumption and biochemical parameters mainly related to lipid metabolism, and this accompanied typical changes in the gene expression. Most of the genes modulated by corn oil were related to cholesterol or fatty acid metabolism (e.g., CYP7A1, CYP8B1, 3-hydroxy-3-methylglutaryl-Coenzyme A reductase, squalene epoxidase, angiopoietin-like protein 4, fatty acid synthase, fatty acid binding proteins), suggesting that the response was physiologic to the oil intake. Many of the lipid-related genes showed circadian rhythm within a day, but the expression pattern of general clock genes (e.g., period 2, arylhydrocarbon nuclear receptor translocator-like, D site albumin promoter binding protein) were unaffected by corn oil, suggesting that the effects are specific for lipid metabolism. These results would be useful for usage of the database especially when drugs with different vehicle control are compared.

Structural Analysis and Involvement in Plant Innate Immunity of Xanthomonas axonopodis pv. citri Lipopolysaccharide*

PubMed Central

Casabuono, Adriana; Petrocelli, Silvana; Ottado, Jorgelina; Orellano, Elena G.; Couto, Alicia S.

2011-01-01

Xanthomonas axonopodis pv. citri (Xac) causes citrus canker, provoking defoliation and premature fruit drop with concomitant economical damage. In plant pathogenic bacteria, lipopolysaccharides are important virulence factors, and they are being increasingly recognized as major pathogen-associated molecular patterns for plants. In general, three domains are recognized in a lipopolysaccharide: the hydrophobic lipid A, the hydrophilic O-antigen polysaccharide, and the core oligosaccharide, connecting lipid A and O-antigen. In this work, we have determined the structure of purified lipopolysaccharides obtained from Xanthomonas axonopodis pv. citri wild type and a mutant of the O-antigen ABC transporter encoded by the wzt gene. High pH anion exchange chromatography and matrix-assisted laser desorption/ionization mass spectrum analysis were performed, enabling determination of the structure not only of the released oligosaccharides and lipid A moieties but also the intact lipopolysaccharides. The results demonstrate that Xac wild type and Xacwzt LPSs are composed mainly of a penta- or tetra-acylated diglucosamine backbone attached to either two pyrophosphorylethanolamine groups or to one pyrophosphorylethanolamine group and one phosphorylethanolamine group. The core region consists of a branched oligosaccharide formed by Kdo2Hex6GalA3Fuc3NAcRha4 and two phosphate groups. As expected, the presence of a rhamnose homo-oligosaccharide as O-antigen was determined only in the Xac wild type lipopolysaccharide. In addition, we have examined how lipopolysaccharides from Xac function in the pathogenesis process. We analyzed the response of the different lipopolysaccharides during the stomata aperture closure cycle, the callose deposition, the expression of defense-related genes, and reactive oxygen species production in citrus leaves, suggesting a functional role of the O-antigen from Xac lipopolysaccharides in the basal response. PMID:21596742

Fractionation of Hydrogen Isotopes by Sulfate- and Nitrate-Reducing Bacteria.

PubMed

Osburn, Magdalena R; Dawson, Katherine S; Fogel, Marilyn L; Sessions, Alex L

2016-01-01

Hydrogen atoms from water and food are incorporated into biomass during cellular metabolism and biosynthesis, fractionating the isotopes of hydrogen-protium and deuterium-that are recorded in biomolecules. While these fractionations are often relatively constant in plants, large variations in the magnitude of fractionation are observed for many heterotrophic microbes utilizing different central metabolic pathways. The correlation between metabolism and lipid δ(2)H provides a potential basis for reconstructing environmental and ecological parameters, but the calibration dataset has thus far been limited mainly to aerobes. Here we report on the hydrogen isotopic fractionations of lipids produced by nitrate-respiring and sulfate-reducing bacteria. We observe only small differences in fractionation between oxygen- and nitrate-respiring growth conditions, with a typical pattern of variation between substrates that is broadly consistent with previously described trends. In contrast, fractionation by sulfate-reducing bacteria does not vary significantly between different substrates, even when autotrophic and heterotrophic growth conditions are compared. This result is in marked contrast to previously published observations and has significant implications for the interpretation of environmental hydrogen isotope data. We evaluate these trends in light of metabolic gene content of each strain, growth rate, and potential flux and reservoir-size effects of cellular hydrogen, but find no single variable that can account for the differences between nitrate- and sulfate-respiring bacteria. The emerging picture of bacterial hydrogen isotope fractionation is therefore more complex than the simple correspondence between δ(2)H and metabolic pathway previously understood from aerobes. Despite the complexity, the large signals and rich variability of observed lipid δ(2)H suggest much potential as an environmental recorder of metabolism.

Structural analysis and involvement in plant innate immunity of Xanthomonas axonopodis pv. citri lipopolysaccharide.

PubMed

Casabuono, Adriana; Petrocelli, Silvana; Ottado, Jorgelina; Orellano, Elena G; Couto, Alicia S

2011-07-22

Xanthomonas axonopodis pv. citri (Xac) causes citrus canker, provoking defoliation and premature fruit drop with concomitant economical damage. In plant pathogenic bacteria, lipopolysaccharides are important virulence factors, and they are being increasingly recognized as major pathogen-associated molecular patterns for plants. In general, three domains are recognized in a lipopolysaccharide: the hydrophobic lipid A, the hydrophilic O-antigen polysaccharide, and the core oligosaccharide, connecting lipid A and O-antigen. In this work, we have determined the structure of purified lipopolysaccharides obtained from Xanthomonas axonopodis pv. citri wild type and a mutant of the O-antigen ABC transporter encoded by the wzt gene. High pH anion exchange chromatography and matrix-assisted laser desorption/ionization mass spectrum analysis were performed, enabling determination of the structure not only of the released oligosaccharides and lipid A moieties but also the intact lipopolysaccharides. The results demonstrate that Xac wild type and Xacwzt LPSs are composed mainly of a penta- or tetra-acylated diglucosamine backbone attached to either two pyrophosphorylethanolamine groups or to one pyrophosphorylethanolamine group and one phosphorylethanolamine group. The core region consists of a branched oligosaccharide formed by Kdo₂Hex₆GalA₃Fuc3NAcRha₄ and two phosphate groups. As expected, the presence of a rhamnose homo-oligosaccharide as O-antigen was determined only in the Xac wild type lipopolysaccharide. In addition, we have examined how lipopolysaccharides from Xac function in the pathogenesis process. We analyzed the response of the different lipopolysaccharides during the stomata aperture closure cycle, the callose deposition, the expression of defense-related genes, and reactive oxygen species production in citrus leaves, suggesting a functional role of the O-antigen from Xac lipopolysaccharides in the basal response.

Association of triglycerides and new lipid markers with the incidence of hypertension in a Spanish cohort.

PubMed

Sánchez-Íñigo, Laura; Navarro-González, David; Pastrana-Delgado, Juan; Fernández-Montero, Alejandro; Martínez, J Alfredo

2016-07-01

Triglycerides and high-density lipoprotein cholesterol (HDL-C) are known to be risk factors for cardiovascular disease. However, there has been limited knowledge on the relationship between triglycerides and incident hypertension. The associations of incident hypertension with triglycerides and triglycerides-related indices such as triglycerides to HDL-C ratio (TG/HDL-C) and triglyceride-glucose index (TyG) were evaluated. Data from 3637 participants from the Vascular Metabolic Clinica Universidad Navarra cohort were followed-up during a mean of 8.49 years. A Cox proportional hazard ratio with repeated measures analyses was performed to assess the risk of developing hypertension across the quintiles of triglycerides, TG/HDL-C ratio, and TyG index. The risk of developing hypertension was 47% and 73% greater for those in the fourth and fifth quintiles of triglycerides, after adjusting for age, sex, BMI, cigarette smoking, daily alcohol intake, lifestyle pattern, type 2 diabetes, antiaggregation therapy, low-density lipoprotein cholesterol, SBP, and DBP. In men, those in the top quintile of triglycerides, TG/HDL-C ratio or TyG index were two times more likely to develop hypertension than those in the bottom quintile. In women, the effect was attenuated although the risk of hypertension rose with increasing quintiles (P for trend <0.05). The results were consistent when analyses were restricted to those participants without diabetes and obesity at baseline. Our results evidenced the associations between triglycerides-related variables and incident hypertension independently of adiposity. This association was stronger than those observed for other commonly used lipid parameters or lipid ratios, such as the TC/HDL-C ratio. : http://links.lww.com/HJH/A620.

The Arabidopsis sn-1-specific mitochondrial acylhydrolase AtDLAH is positively correlated with seed viability

PubMed Central

Seo, Young Sam; Kim, Eun Yu; Kim, Woo Taek

2011-01-01

Lipid-derived molecules produced by acylhydrolases play important roles in the regulation of diverse cellular functions in plants. In Arabidopsis, the DAD1-like phospholipase A1 family consists of 12 members, all of which possess a lipase 3 domain. In this study, the biochemical and cellular functions of AtDLAH, an Arabidopsis thaliana DAD1-like acylhydrolase, were examined. Bacterially expressed AtDLAH contained phospholipase A1 activity for catalysing the hydrolysis of phospholipids at the sn-1 position. However, AtDLAH displayed an even stronger preference for 1-lysophosphatidylcholine, 1-monodiacylglycerol, and phosphatidic acid, suggesting that AtDLAH is a sn-1-specific acylhydrolase. The AtDLAH gene was highly expressed in young seedlings, and its encoded protein was exclusively localized to the mitochondria. AtDLAH-overexpressing transgenic seeds (35S:AtDLAH) were markedly tolerant to accelerated-ageing treatment and thus had higher germination percentages than wild-type seeds. In contrast, the atdlah loss-of-function knockout mutant seeds were hypersusceptible to accelerated-ageing conditions. The 35S:AtDLAH seeds, as opposed to the atdlah seeds, exhibited a dark red staining pattern following tetrazolium treatment under both normal and accelerated-ageing conditions, suggesting that AtDLAH expression is positively correlated with seed viability. The enhanced viability of 35S:AtDLAH seeds was accompanied by more densely populated epidermal cells, lower levels of accumulated lipid hydroperoxides, and higher levels of polar lipids as compared with wild-type and atdlah mutant seeds. These results suggest that AtDLAH, a mitochondrial-localized sn-1-specific acylhydrolase, plays an important role in Arabidopsis seed viability. PMID:21856645

Influence of depth on sex-specific energy allocation patterns in a tropical reef fish

NASA Astrophysics Data System (ADS)

Hoey, J.; McCormick, M. I.; Hoey, A. S.

2007-09-01

The effect of depth on the distribution and sex-specific energy allocation patterns of a common coral reef fish, Chrysiptera rollandi (Pomacentridae), was investigated using depth-stratified collections over a broad depth range (5-39 m) and a translocation experiment. C. rollandi consistently selected rubble habitats at each depth, however abundance patterns did not reflect the availability of the preferred microhabitat suggesting a preference for depth as well as microhabitat. Reproductive investment (gonado-somatic index), energy stores (liver cell density and hepatocyte vacuolation), and overall body condition (hepato-somatic index and Fulton’s K) of female fish varied significantly among depths and among the three reefs sampled. Male conspecifics displayed no variation between depth or reef. Depth influenced growth dynamics, with faster initial growth rates and smaller mean asymptotic lengths with decreasing depth. In female fish, relative gonad weight and overall body condition (Fulton’s K and hepato-somatic index) were generally higher in shallower depths (≤10 m). Hepatic lipid storage was highest at the deepest sites sampled on each reef, whereas hepatic glycogen stores tended to decrease with depth. Depth was found to influence energy allocation dynamics in C. rollandi. While it is unclear what processes directly influenced the depth-related patterns in energy allocation, this study shows that individuals across a broad depth gradient are not all in the same physiological state and may contribute differentially to the population reproductive output.

Patterns of type 2 diabetes monitoring in rural towns: How does frequency of HbA1c and lipid testing compare with existing guidelines?

PubMed

Paul, Christine L; Piterman, Leon; Shaw, Jonathan E; Kirby, Catherine; Barker, Daniel; Robinson, Jennifer; Forshaw, Kristy L; Sikaris, Kenneth A; Bisquera, Alessandra; Sanson-Fisher, Robert W

2016-12-01

To indicate levels of monitoring of type 2 diabetes in rural and regional Australia by examining patterns of glycated haemoglobin (HbA1c) and blood lipid testing. Retrospective analysis of pathology services data from twenty regional and rural towns in eastern Australia over 24 months. Of 13 105 individuals who had either a single HbA1c result ≥7.0% (53 mmol mol -1 ); or two or more HbA1c tests within the study period. Frequency of testing of HbA1c and blood lipids (cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol and triglycerides) were compared with guideline recommendations. About 58.3% of patients did not have the recommended 6-monthly HbA1c tests and 30.6% did not have annual lipid testing. For those who did not receive tests at the recommended interval, the mean between-test interval was 10.5 months (95% CI = 7.5-13.5) rather than 6 months for HbA1c testing; and 15.7 (95% CI = 13.3-18.1) months rather than annually for blood lipids. For those with at least one out-of-range test result, 77% of patients failed to receive a follow-up HbA1c test and 86.5% failed to receive a follow-up blood lipid test within the recommended 3 months. Patients less than 50 years of age, living in a more remote area and with poor diabetes control were less likely to have testing at the recommended intervals (P < 0.0001). Although poor diabetes testing is not limited to rural areas, more intensive diabetes monitoring is likely to be needed for patients living in non-metropolitan areas, particularly for some subgroups. © 2016 National Rural Health Alliance Inc.

Ethnic differences in blood lipids and dietary intake between UK children of black African, black Caribbean, South Asian, and white European origin: the Child Heart and Health Study in England (CHASE).

PubMed

Donin, Angela S; Nightingale, Claire M; Owen, Christopher G; Rudnicka, Alicja R; McNamara, Mary C; Prynne, Celia J; Stephen, Alison M; Cook, Derek G; Whincup, Peter H

2010-10-01

Ischemic heart disease (IHD) rates are lower in UK black Africans and black Caribbeans and higher in South Asians when compared with white Europeans. Ethnic differences in lipid concentrations may play a part in these differences. The objective was to investigate blood lipid and dietary patterns in UK children from different ethnic groups. This was a cross-sectional study in 2026 UK children (including 285 black Africans, 188 black Caribbeans, 534 South Asians, and 512 white Europeans) attending primary schools in London, Birmingham, and Leicester. We measured fasting blood lipid concentrations and collected 24-h dietary recalls. In comparison with white Europeans, black African children had lower total cholesterol (-0.14 mmol/L; 95% CI: -0.25, -0.04 mmol/L), LDL-cholesterol (-0.10 mmol/L; 95% CI: -0.20, -0.01 mmol/L), and triglyceride concentrations (proportional difference: -0.11 mmol/L; 95% CI: -0.16, -0.06 mmol/L); HDL-cholesterol concentrations were similar. Lower saturated fat intakes (-1.4%; 95% CI: -1.9%, -0.9%) explained the differences between total and LDL cholesterol. Black Caribbean children had total, LDL-cholesterol, HDL-cholesterol, and triglyceride concentrations similar to those for white Europeans, with slightly lower saturated fat intakes. South Asian children had total and LDL-cholesterol concentrations similar to those for white Europeans, lower HDL-cholesterol concentrations (-0.7 mmol/L; 95% CI: -0.11, -0.03 mmol/L), and elevated triglyceride concentrations (proportional difference: 0.14 mmol/L; 95% CI: 0.09, 0.20 mmol/L); higher polyunsaturated and monounsaturated fat intakes did not explain these lipid differences. Only black African children had a blood lipid profile and associated dietary pattern likely to protect against future IHD. The loss of historically lower LDL-cholesterol concentrations among UK black Caribbeans and South Asians may have important adverse consequences for future IHD risk in these groups.

Lipid-based colloidal carriers for peptide and protein delivery – liposomes versus lipid nanoparticles

PubMed Central

Martins, Susana; Sarmento, Bruno; Ferreira, Domingos C; Souto, Eliana B

2007-01-01

This paper highlights the importance of lipid-based colloidal carriers and their pharmaceutical implications in the delivery of peptides and proteins for oral and parenteral administration. There are several examples of biomacromolecules used nowadays in the therapeutics, which are promising candidates to be delivered by means of liposomes and lipid nanoparticles, such as solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC). Several production procedures can be applied to achieve a high association efficiency between the bioactives and the carrier, depending on the physicochemical properties of both, as well as on the production procedure applied. Generally, this can lead to improved bioavailability, or in case of oral administration a more consistent temporal profile of absorption from the gastrointestinal tract. Advantages and drawbacks of such colloidal carriers are also pointed out. This article describes strategies used for formulation of peptides and proteins, methods used for assessment of association efficiency and practical considerations regarding the toxicological concerns. PMID:18203427

Quorum sensing molecules in activated sludge could trigger microalgae lipid synthesis.

PubMed

Zhang, Chaofan; Li, Qingcheng; Fu, Liang; Zhou, Dandan; Crittenden, John C

2018-05-18

Cultivating microalgae using wastewater is an economical strategy to produce biofuel; however, microbial contamination has to be controlled strictly. Microalgae lipid accumulation can be triggered by environmental pressures, and here, we studied whether microbial contamination is the pressure for microalgae. We hypothesized this pressure was forced via cell-to-cell communication with quorum sensing molecules (QSMs). In this work, we verified the impacts of QSMs produced by activated sludge (wastewater-born microbial consortiums) on both lipid content and biomass production of the microalgae Chlorophyta sp., since in combination, they determined lipid productivity. With QSMs stress, the lipid content of Chlorophyta sp. increased by ∼84%, while biomass production decreased only slightly. Consistently, enzymes on the fatty acid synthesis pathways were generally up-regulated, while they were slightly down-regulated for DNA replication. In summary, the total lipid production improved by 86%. These results revealed the positive effects of microbial contamination on microalgae biofuel production. Copyright © 2018 Elsevier Ltd. All rights reserved.

Changes in fatty acid composition and lipid profile during koji fermentation and their relationships with soy sauce flavour.

PubMed

Feng, Yunzi; Chen, Zhiyao; Liu, Ning; Zhao, Haifeng; Cui, Chun; Zhao, Mouming

2014-09-01

Evolution of lipids during koji fermentation and the effect of lipase supplementation on the sensory properties of soy sauce were investigated. Results showed that total lipids of the koji samples were in the range of 16-21%. The extracted lipid of initial koji consisted mainly of triacylglycerols (TAGs, >98%), followed by phospholipids (PLs), diglycerides (DAGs), monoacylglycerols (MAGs) and free fatty acids (FFAs). As the fermentation proceeded, peroxide value of the lipids decreased while carbonyl value increased (p<0.05). Linoleic acid was utilised fastest according to the fatty acid composition of total lipids, and preferential degradation of PLs to liberate FFAs was also observed. Moreover, phospholipase supplementation had significant influence on the sensory characteristics of soy sauce, especially enhanced (p<0.05) scores for the umami and kokumi taste attributes. All these results indicated that the control of PLs utilisation during fermentation was a potential method to improve soy sauce's characteristic taste. Copyright © 2014 Elsevier Ltd. All rights reserved.

Multi-parameter in vitro toxicity testing of crizotinib, sunitinib, erlotinib, and nilotinib in human cardiomyocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doherty, Kimberly R., E-mail: kimberly.doherty@quintiles.com; Wappel, Robert L.; Talbert, Dominique R.

2013-10-01

Tyrosine kinase inhibitors (TKi) have greatly improved the treatment and prognosis of multiple cancer types. However, unexpected cardiotoxicity has arisen in a subset of patients treated with these agents that was not wholly predicted by pre-clinical testing, which centers around animal toxicity studies and inhibition of the human Ether-à-go-go-Related Gene (hERG) channel. Therefore, we sought to determine whether a multi-parameter test panel assessing the effect of drug treatment on cellular, molecular, and electrophysiological endpoints could accurately predict cardiotoxicity. We examined how 4 FDA-approved TKi agents impacted cell viability, apoptosis, reactive oxygen species (ROS) generation, metabolic status, impedance, and ion channelmore » function in human cardiomyocytes. The 3 drugs clinically associated with severe cardiac adverse events (crizotinib, sunitinib, nilotinib) all proved to be cardiotoxic in our in vitro tests while the relatively cardiac-safe drug erlotinib showed only minor changes in cardiac cell health. Crizotinib, an ALK/MET inhibitor, led to increased ROS production, caspase activation, cholesterol accumulation, disruption in cardiac cell beat rate, and blockage of ion channels. The multi-targeted TKi sunitinib showed decreased cardiomyocyte viability, AMPK inhibition, increased lipid accumulation, disrupted beat pattern, and hERG block. Nilotinib, a second generation Bcr-Abl inhibitor, led to increased ROS generation, caspase activation, hERG block, and an arrhythmic beat pattern. Thus, each drug showed a unique toxicity profile that may reflect the multiple mechanisms leading to cardiotoxicity. This study demonstrates that a multi-parameter approach can provide a robust characterization of drug-induced cardiomyocyte damage that can be leveraged to improve drug safety during early phase development. - Highlights: • TKi with known adverse effects show unique cardiotoxicity profiles in this panel. • Crizotinib increases ROS, apoptosis, and cholesterol as well as alters beat rate. • Sunitinib inhibits AMPK, increases lipids and alters the cardiac beat pattern. • Nilotinib causes ROS and caspase activation, decreased lipids and arrhythmia. • Erlotinib did not impact ROS, caspase, or lipid levels or affect the beat pattern.« less

The role of nutrient reserves for clutch formation by Northern Pintails in Alaska

USGS Publications Warehouse

Esler, Daniel N.; Grand, James B.

1994-01-01

We analyzed carcass composition of female Northern Pintails (Anas acuta) in Alaska to assess the importance of nutrient reserves for formation of first clutches (n = 85) and renests (n = 39). Habitat (tundra vs. boreal forest), hen age (yearling vs. adult), and year (1990 vs. 1991) did not affect nutrient reserve use. During formation of first clutches, Northern Pintail hens relied on lipid reserves more than any other duck species that has been studied. For much of the nesting season, lipid reserves were used to meet costs beyond those incurred by clutch formation. Date of initiation of rapid follicle growth was related to lipid reserve dynamics; lipid reserves at initiation and the rate of lipid use both declined through the season. Protein reserves declined slightly with commitment of protein to the clutch and with date of initiation of rapid follicle growth. Use of mineral reserves for first nests was negligible. Renesting females did not use nutrient reserves. Lipid reserve levels were positively related to the amount of lipid reserves needed to complete the clutch and clutch sizes predicted from a lipid dynamics model were consistent with known clutch sizes. Similar relationships did not exist for protein. We suggest that lipid reserve levels affect timing of nesting and proximately limit clutch size of Northern Pintails.

A new in vitro lipid digestion - in vivo absorption model to evaluate the mechanisms of drug absorption from lipid-based formulations.

PubMed

Crum, Matthew F; Trevaskis, Natalie L; Williams, Hywel D; Pouton, Colin W; Porter, Christopher J H

2016-04-01

In vitro lipid digestion models are commonly used to screen lipid-based formulations (LBF), but in vitro-in vivo correlations are in some cases unsuccessful. Here we enhance the scope of the lipid digestion test by incorporating an absorption 'sink' into the experimental model. An in vitro model of lipid digestion was coupled directly to a single pass in situ intestinal perfusion experiment in an anaesthetised rat. The model allowed simultaneous real-time analysis of the digestion and absorption of LBFs of fenofibrate and was employed to evaluate the influence of formulation digestion, supersaturation and precipitation on drug absorption. Formulations containing higher quantities of co-solvent and surfactant resulted in higher supersaturation and more rapid drug precipitation in vitro when compared to those containing higher quantities of lipid. In contrast, when the same formulations were examined using the coupled in vitro lipid digestion - in vivo absorption model, drug flux into the mesenteric vein was similar regardless of in vitro formulation performance. For some drugs, simple in vitro lipid digestion models may underestimate the potential for absorption from LBFs. Consistent with recent in vivo studies, drug absorption for rapidly absorbed drugs such as fenofibrate may occur even when drug precipitation is apparent during in vitro digestion.

Evaluation of Physarum polycephalum plasmodial growth and lipid production using rice bran as a carbon source.

PubMed

Tran, Hanh; Stephenson, Steven; Pollock, Erik

2015-08-01

The myxomycete Physarum polycephalum appears to have remarkable potential as a lipid source for biodiesel production. The present study evaluated the use of rice bran as a carbon source and determined the medium components for optimum growth and lipid production for this organism. Optimization of medium components by response surface methodology showed that rice bran and yeast extract had significant influences on lipid and biomass production. The optimum medium consisted of 37.5 g/L rice bran, 0.79 g/L yeast extract and 12.5 g/L agar, and this yielded 7.5 g/L dry biomass and 0.9 g/L lipid after 5 days. The biomass and lipid production profiles revealed that these parameters increased over time and reached their maximum values (10.5 and 1.26 g/L, respectively) after 7 days. Physarum polycephalum growth decreased on the spent medium but using the latter increased total biomass and lipid concentrations to 14.3 and 1.72 g/L, respectively. An effective method for inoculum preparation was developed for biomass and lipid production by P. polycephalum on a low-cost medium using rice bran as the main carbon source. These results also demonstrated the feasibility of scaling up and reusing the medium for additional biomass and lipid production.

Planktonic Euryarchaeota are a significant source of archaeal tetraether lipids in the ocean.

PubMed

Lincoln, Sara A; Wai, Brenner; Eppley, John M; Church, Matthew J; Summons, Roger E; DeLong, Edward F

2014-07-08

Archaea are ubiquitous in marine plankton, and fossil forms of archaeal tetraether membrane lipids in sedimentary rocks document their participation in marine biogeochemical cycles for >100 million years. Ribosomal RNA surveys have identified four major clades of planktonic archaea but, to date, tetraether lipids have been characterized in only one, the Marine Group I Thaumarchaeota. The membrane lipid composition of the other planktonic archaeal groups--all uncultured Euryarchaeota--is currently unknown. Using integrated nucleic acid and lipid analyses, we found that Marine Group II Euryarchaeota (MG-II) contributed significantly to the tetraether lipid pool in the North Pacific Subtropical Gyre at shallow to intermediate depths. Our data strongly suggested that MG-II also synthesize crenarchaeol, a tetraether lipid previously considered to be a unique biomarker for Thaumarchaeota. Metagenomic datasets spanning 5 y indicated that depth stratification of planktonic archaeal groups was a stable feature in the North Pacific Subtropical Gyre. The consistent prevalence of MG-II at depths where the bulk of exported organic matter originates, together with their ubiquitous distribution over diverse oceanic provinces, suggests that this clade is a significant source of tetraether lipids to marine sediments. Our results are relevant to archaeal lipid biomarker applications in the modern oceans and the interpretation of these compounds in the geologic record.

Revisiting "You are what you eat, +1‰": Bacterial Trophic Structure and the Sedimentary Record

NASA Astrophysics Data System (ADS)

Pearson, A.; Tang, T.; Mohr, W.; Sattin, S.

2015-12-01

"You are what you eat, +1‰" is a central principle of carbon stable isotope (δ13C) distributions and is widely applied to understand the structure and ordering of macrobiotic ecosystems. Although based on observations from multicellular organisms that are able to ingest "food", this idea also has been applied to Precambrian ecosystems dominated by unicellular, microbial life, with the suggestion that such systems could sustain ordered trophic structures observable in their isotopes. However, using a new approach to community profiling known as protein stable isotope fingerprinting (P-SIF), we find that the carbon isotope ratios of whole proteins separated from environmental samples show differences only between metabolically-distinct autotrophs; heterotrophs are not 13C-enriched. In parallel, a survey of the relative distribution of 13C between biochemical classes - specifically acetogenic lipids, isoprenoid lipids, amino acids, and nucleic acids/sugars - across a variety of bacterial species appears to be a function of the main carbon metabolite, not an indicator of heterotrophy vs. autotrophy. Indeed, autotrophy, heterotrophy, and mixotrophy all are indistinguishable when the primary food source is fresh photosynthate, i.e., sugar. Significant assimilation of acetate is diagnosed by acetogenic lipids that are relatively 13C-enriched vs. isoprenoid lipids. Mixed-substrate heterotrophy, in contrast, satisfies the classic "…+1‰" rule for bulk biomass, yet simultaneously it collapses the biochemical patterns of 13C almost completely. Together these observations point to a paradigm shift for understanding the preservation of bulk organic and lipid δ13C signatures in the rock record, suggesting that patterns of δ13Corg must primarily reflect changing carbon inputs, not the extent or intensity of heterotrophy.

Molecular imaging of lipids in cells and tissues

NASA Astrophysics Data System (ADS)

Borner, Katrin; Malmberg, Per; Mansson, Jan-Eric; Nygren, Hakan

2007-02-01

The distribution pattern of lipid species in biological tissues was analyzed with imaging mass spectrometry (TOF-SIMS; time-of-flight secondary ion mass spectrometry). The first application shows distribution of a glycosphingolipid, the galactosylceramide-sulfate (sulfatide) with different hydrocarbon chain lengths and the fatty acids palmitate and oleate in rat cerebellum. Sulfatides were seen localized in regions suggested as paranodal areas of rat cerebellar white matter as well as in the granular layer, with highest concentrations at the borders of the white matter. Different distribution patterns could be shown for the fatty acid C16:0 palmitate and C18:1 oleate in rat cerebellum, which seem to origin partly from the hydrocarbon chains of phosphatidylcholine. Results were shown for two different tissue preparation methods, which were plunge-freezing and cryostat sectioning as well as high-pressure freezing, freeze-fracturing and freeze-drying. The second application shows TOF-SIMS analysis on a biological trial of choleratoxin treatment in mouse intestine. The effect of cholera toxin on lipids in the intestinal epithelium was shown by comparing control and cholera toxin treated mouse intestine samples. A significant increase of the cholesterol concentration was seen after treatment. Cholesterol was mainly localized to the brush border of enterocytes of the intestinal villi, which could be explained by the presence of cholesterol-rich lipid rafts present on the microvilli or by relations to cholesterol uptake. After cholera toxin exposure, cholesterol was seen increased in the nuclei of enterocytes and apparently in the interstitium of the villi. We find that imaging TOF-SIMS is a powerful tool for studies of lipid distributions in cells and tissues, enabling the elucidation of their role in cell function and biology.

Comparison of Blood Lipids, Blood Pressures and Left Ventricular Cavity Dimension between Soccer Players and Non-Athletes

ERIC Educational Resources Information Center

Gokhan, Ismail; Kurkcu, Recep; Cekin, Resul

2013-01-01

In this study, it was aimed to compare the investigate the effects of regular exercise on blood lipids, blood pressure and left ventricular cavity dimensions function between soccer players and non-athletes in football players. This study consisted included a total of 30 subjects, including an experimental group including 18 soccer players…

A computer simulation approach to quantify the true area and true area compressibility modulus of biological membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chacón, Enrique, E-mail: echacon@icmm.csic.es; Tarazona, Pedro, E-mail: pedro.tarazona@uam.es; Bresme, Fernando, E-mail: f.bresme@imperial.ac.uk

We present a new computational approach to quantify the area per lipid and the area compressibility modulus of biological membranes. Our method relies on the analysis of the membrane fluctuations using our recently introduced coupled undulatory (CU) mode [Tarazona et al., J. Chem. Phys. 139, 094902 (2013)], which provides excellent estimates of the bending modulus of model membranes. Unlike the projected area, widely used in computer simulations of membranes, the CU area is thermodynamically consistent. This new area definition makes it possible to accurately estimate the area of the undulating bilayer, and the area per lipid, by excluding any contributionsmore » related to the phospholipid protrusions. We find that the area per phospholipid and the area compressibility modulus features a negligible dependence with system size, making possible their computation using truly small bilayers, involving a few hundred lipids. The area compressibility modulus obtained from the analysis of the CU area fluctuations is fully consistent with the Hooke’s law route. Unlike existing methods, our approach relies on a single simulation, and no a priori knowledge of the bending modulus is required. We illustrate our method by analyzing 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayers using the coarse grained MARTINI force-field. The area per lipid and area compressibility modulus obtained with our method and the MARTINI forcefield are consistent with previous studies of these bilayers.« less

Vesicle solubilization by bile salts: comparison of macroscopic theory and simulation.

PubMed

Haustein, M; Wahab, M; Mögel, H-J; Schiller, P

2015-04-14

Lipid metabolism is accompanied by the solubilization of lipid bilayer membranes by bile salts. We use Brownian dynamics simulations to study the solubilization of model membranes and vesicles by sodium cholate. The solubilization pathways of small and large vesicles are found to be different. Both results for small and large vesicles can be compared with predictions of a macroscopic theoretical description. The line tension of bilayer edges is an important parameter in the solubilization process. We propose a simple method to determine the line tension by analyzing the shape fluctuations of planar membrane patches. Macroscopic mechanical models provide a reasonable explanation for processes observed when a spherical vesicle consisting of lipids and adsorbed bile salt molecules is transformed into mixed lipid-bile salt micelles.

LIPIDS OF SARCINA LUTEA II.

PubMed Central

Albro, Phillip W.; Huston, Charles K.

1964-01-01

Albro, Phillip W. (Ft. Detrick, Frederick, Md.), and Charles K. Huston. Lipids of Sarcina lutea. II. Hydrocarbon content of the lipid extracts. J. Bacteriol. 88:981–986. 1964.—The hydrocarbon fraction from Sarcina lutea lipid extracts was characterized by a combination of thin-layer and gas-liquid chromatography and infrared spectroscopy. A total of 37 components were observed by gas-liquid chromatography of this material. A breakdown of the components into classes indicated a composition consisting of 88.9% n-saturates, 1.2% monoenes, 2.1% dienes, 5.0% trienes, and 0.6% branched-saturates. Less than 0.1% of the hydrocarbon material was aromatic. No attempt was made in this study to relate the composition to either origin or function in the cell. PMID:14222808

Carbon nanotubes for stabilization of nanostructured lipid particles

NASA Astrophysics Data System (ADS)

Gaunt, Nicholas P.; Patil-Sen, Yogita; Baker, Matthew J.; Kulkarni, Chandrashekhar V.

2014-12-01

Carbon nanotubes (CNTs) are increasingly studied for innovative biotechnological applications particularly where they are combined with essential biological materials like lipids. Lipids have been used earlier for enhancing the dispersibility of CNTs in aqueous solutions. Here we report a novel application of CNTs for stabilization of internally self-assembled nanostructured lipid particles of 2-5 μm size. Single-walled (pristine) as well as -OH and -COOH functionalized multi-walled CNTs were employed to produce nanostructured emulsions which stayed stable for months and could be re-dispersed after complete dehydration. Concentrations of CNTs employed for stabilization were very low; moreover CNTs were well-decorated with lipid molecules. These features contribute towards reducing their toxicity and improving biocompatibility for biomedical and pharmaceutical applications. Our approach paves the way for future development of combination therapies employing both CNTs and nanostructured lipid self-assembly together as carriers of different drugs.Carbon nanotubes (CNTs) are increasingly studied for innovative biotechnological applications particularly where they are combined with essential biological materials like lipids. Lipids have been used earlier for enhancing the dispersibility of CNTs in aqueous solutions. Here we report a novel application of CNTs for stabilization of internally self-assembled nanostructured lipid particles of 2-5 μm size. Single-walled (pristine) as well as -OH and -COOH functionalized multi-walled CNTs were employed to produce nanostructured emulsions which stayed stable for months and could be re-dispersed after complete dehydration. Concentrations of CNTs employed for stabilization were very low; moreover CNTs were well-decorated with lipid molecules. These features contribute towards reducing their toxicity and improving biocompatibility for biomedical and pharmaceutical applications. Our approach paves the way for future development of combination therapies employing both CNTs and nanostructured lipid self-assembly together as carriers of different drugs. Electronic supplementary information (ESI) available: Concentration series studies with Raman spectroscopy and small angle X-ray diffraction pattern for dry lipid and dehydrated CNT-lipid particles support the article. See DOI: 10.1039/c4nr05593d

Thylakoid membrane landscape in the sixties: a tribute to Andrew Benson.

PubMed

Anderson, Jan M

2007-05-01

Prior to the 1960s, the model for the molecular structure of cell membranes consisted of a lipid bilayer held in place by a thin film of electrostatically-associated protein stretched over the bilayer surface: (the Danielli-Davson-Robertson "unit membrane" model). Andrew Benson, an expert in the lipids of chloroplast thylakoid membranes, questioned the relevance of the unit membrane model for biological membranes, especially for thylakoid membranes, instead of emphasizing evidence in favour of hydrophobic interactions of membrane lipids within complementary hydrophobic regions of membrane-spanning proteins. With Elliot Weier, Benson postulated a remarkable subunit lipoprotein monolayer model for thylakoids. Following the advent of freeze fracture microscopy and the fluid lipid-protein mosaic model by Singer and Nicolson, the subunits, membrane-spanning integral proteins, span a dynamic lipid bilayer. Now that high resolution X-ray structures of photosystems I and II are being revealed, the seminal contribution of Andrew Benson can be appreciated.

Veganism Is a Viable Alternative to Conventional Diet Therapy for Improving Blood Lipids and Glycemic Control.

PubMed

Trepanowski, John F; Varady, Krista A

2015-01-01

The American Diabetes Association (ADA) and the National Cholesterol Education Program (NCEP) have each outlined a set of dietary recommendations aimed at improving glycemic control and blood lipids, respectively. However, traditional vegan diets (low-fat diets that proscribe animal product consumption) are also effective at improving glycemic control, and dietary portfolios (vegan diets that contain prescribed amounts of plant sterols, viscous fibers, soy protein, and nuts) are also effective at improving blood lipids. The purpose of this review was to compare the effects of traditional vegan diets and dietary portfolios with ADA and NCEP diets on body weight, blood lipids, blood pressure, and glycemic control. The main findings are that traditional vegan diets appear to improve glycemic control better than ADA diets in individuals with type 2 diabetes mellitus (T2DM), while dietary portfolios have been consistently shown to improve blood lipids better than NCEP diets in hypercholesterolemic individuals.

Fleshy-fruits phenology: temporal variability on quantity and quality of animal-dispersed fruits in a cerrado-savanna

NASA Astrophysics Data System (ADS)

de Camargo, Maria Gabriela G.; Cazetta, Eliana; Schaefer, Martin; Morellato, L. Patrícia C.

2014-05-01

Time and quantity and quality of fruits and seeds produced are limiting factors for the recruitment of new individuals and maintenance plant species. Furthermore, species that produced fruits dispersed by animals have an important role as a source of food for different groups of animals and relay on them to dispersed their seeds. In most of the Brazilian cerrado-savanna, as in others tropical vegetations, there is a predominance of animal-dispersed species, however there is a lack of information about fruit production and its availability over time on tropical savannas. Beyond the comprehension of fruiting patterns and their relation to biotic and abiotic factors, the fruit production over time can be associated with data on fruit quality such as the fruit color and nutritional content. Those combined informations allow us to evaluate the quantity and quality of resources available in a plant community for frugivores and seed predators. For a cerrado-savanna woody community in southeastern Brazil, subjected to a marked seasonal climate, we intended to describe: (i) fruit availability over time (in number and biomass); (ii) nutritional content; and (ii) fruit color patterns over a year. We counted fortnightly the number of ripe fruits and estimated fruit biomass over a year. For the nutritional content, we evaluated the percentage of protein, lipids and carbohydrates in the pulp or aril of fleshy-fruits. We classified fruit colors in red, black, yellow, dark-red, blue and multicolored (when the fruit display is composed by a combination of two non-green colors or more). We observed a period of the highest fruit production in the wet season, with two peaks of production, and a decline in the dry season, a possible period of scarcity. As expected, fruit nutritional content followed mainly the fruiting pattern in biomass. For lipids there was a different seasonal pattern in which lipid-rich fruits were produced mainly at the end of the wet season while fruits with less lipid were fruiting in the first part of the wet season. Fruits of different colors were not equally produced along the year, with black and red fruits more restricted to the wet season, while yellow and multicolour fruits were also observed in the dry season. The cerrado-savanna woody community showed a relevant fruit production in quantity and quality with a high production in biomass of fruits and mainly in the amount of lipids in the pulp. Despite the strong correlation with the seasonal weather, there were differences in the timing of fruit production according to fruit colors.

Structure of bacterial lipopolysaccharides.

PubMed

Caroff, Martine; Karibian, Doris

2003-11-14

Bacterial lipopolysaccharides are the major components of the outer surface of Gram-negative bacteria They are often of interest in medicine for their immunomodulatory properties. In small amounts they can be beneficial, but in larger amounts they may cause endotoxic shock. Although they share a common architecture, their structural details exert a strong influence on their activity. These molecules comprise: a lipid moiety, called lipid A, which is considered to be the endotoxic component, a glycosidic part consisting of a core of approximately 10 monosaccharides and, in "smooth-type" lipopolysaccharides, a third region, named O-chain, consisting of repetitive subunits of one to eight monosaccharides responsible for much of the immunospecificity of the bacterial cell.

Variability of nutrients intake, lipid profile and cardiovascular mortality among geographical areas in Spain: The DRECE study.

PubMed

Gómez de la Cámara, Agustín; De Andrés Esteban, Eva; Urrútia Cuchí, Gerard; Calderón Sandubete, Enrique; Rubio Herrera, Miguel Ángel; Menéndez Orenga, Miguel; Lora Pablos, David

2017-11-07

It has often been suggested that cardiovascular mortality and their geographical heterogeneity are associated with nutrients intake patterns and also lipid profile. The large Spanish study Dieta y Riesgo de Enfermedades Cardiovasculares en España (DRECE) investigated this theory from 1991 to 2010. Out of the 4,783 Spanish individuals making up the DRECE cohort, 220 subjects (148 men and 72 women) died (4.62%) during the course of the study. The mean age of patients who died from cardiovascular causes (32 in all) was 61.08 years 95% CI (57.47-64.69) and 70.91% of them were males. The consumption of nutrients and the lipid profile by geographical area, studied by geospatial models, showed that the east and southern area of the country had the highest fat intake coupled to a high rate of unhealthy lipid profile. It was concluded that the spatial geographical analysis showed a relationship between high fat intake, unhealthy lipid profile and cardiovascular mortality in the different geographical areas, with a high variability within the country.

Functional diversification and specialization of cytosolic 70-kDa heat shock proteins.

PubMed

McCallister, Chelsea; Siracusa, Matthew C; Shirazi, Farzaneh; Chalkia, Dimitra; Nikolaidis, Nikolas

2015-03-20

A fundamental question in molecular evolution is how protein functional differentiation alters the ability of cells and organisms to cope with stress and survive. To answer this question we used two paralogous Hsp70s from mouse and explored whether these highly similar cytosolic molecular chaperones, which apart their temporal expression have been considered functionally interchangeable, are differentiated with respect to their lipid-binding function. We demonstrate that the two proteins bind to diverse lipids with different affinities and therefore are functionally specialized. The observed lipid-binding patterns may be related with the ability of both Hsp70s to induce cell death by binding to a particular plasma-membrane lipid, and the potential of only one of them to promote cell survival by binding to a specific lysosomal-membrane lipid. These observations reveal that two seemingly identical proteins differentially modulate cellular adaptation and survival by having acquired specialized functions via sequence divergence. Therefore, this study provides an evolutionary paradigm, where promiscuity, specificity, sub- and neo-functionalization orchestrate one of the most conserved systems in nature, the cellular stress-response.

Lipid deregulation in UV irradiated skin cells: Role of 25-hydroxycholesterol in keratinocyte differentiation during photoaging.

PubMed

Olivier, Elodie; Dutot, Mélody; Regazzetti, Anne; Dargère, Delphine; Auzeil, Nicolas; Laprévote, Olivier; Rat, Patrice

2017-05-01

Skin photoaging due to UV irradiation is a degenerative process that appears more and more as a growing concern. Lipids, including oxysterols, are involved in degenerative processes; as skin cells contain various lipids, the aim of our study was to evaluate first, changes in keratinocyte lipid levels induced by UV exposure and second, cellular effects of oxysterols in cell morphology and several hallmarks of keratinocyte differentiation. Our mass spectrometry results demonstrated that UV irradiation induces changes in lipid profile of cultured keratinocytes; in particular, ceramides and oxysterols, specifically 25-hydroxycholesterol (25-OH), were increased. Using holography and confocal microscopy analyses, we highlighted cell thickening and cytoskeletal disruption after incubation of keratinocytes with 25-OH. These alterations were associated with keratinocyte differentiation patterns: autophagy stimulation and intracellular calcium increase as measured by cytofluorometry, and increased involucrin level detected by immunocytochemistry. To conclude, oxysterol deregulation could be considered as a common marker of degenerative disorders. During photoaging, 25-OH seems to play a key role inducing morphological changes and keratinocyte differentiation. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

The Tomato MIXTA-Like Transcription Factor Coordinates Fruit Epidermis Conical Cell Development and Cuticular Lipid Biosynthesis and Assembly1

PubMed Central

Lotan, Orfa; Alkan, Noam; Tsimbalist, Tatiana; Rechav, Katya; Fernandez-Moreno, Josefina-Patricia; Widemann, Emilie; Grausem, Bernard; Pinot, Franck; Costa, Fabrizio; Aharoni, Asaph

2015-01-01

The epidermis of aerial plant organs is the primary source of building blocks forming the outer surface cuticular layer. To examine the relationship between epidermal cell development and cuticle assembly in the context of fruit surface, we investigated the tomato (Solanum lycopersicum) MIXTA-like gene. MIXTA/MIXTA-like proteins, initially described in snapdragon (Antirrhinum majus) petals, are known regulators of epidermal cell differentiation. Fruit of transgenically silenced SlMIXTA-like tomato plants displayed defects in patterning of conical epidermal cells. They also showed altered postharvest water loss and resistance to pathogens. Transcriptome and cuticular lipids profiling coupled with comprehensive microscopy revealed significant modifications to cuticle assembly and suggested SlMIXTA-like to regulate cutin biosynthesis. Candidate genes likely acting downstream of SlMIXTA-like included cytochrome P450s (CYPs) of the CYP77A and CYP86A subfamilies, LONG-CHAIN ACYL-COA SYNTHETASE2, GLYCEROL-3-PHOSPHATE SN-2-ACYLTRANSFERASE4, and the ATP-BINDING CASSETTE11 cuticular lipids transporter. As part of a larger regulatory network of epidermal cell patterning and L1-layer identity, we found that SlMIXTA-like acts downstream of SlSHINE3 and possibly cooperates with homeodomain Leu zipper IV transcription factors. Hence, SlMIXTA-like is a positive regulator of both cuticle and conical epidermal cell formation in tomato fruit, acting as a mediator of the tight association between fruit cutin polymer formation, cuticle assembly, and epidermal cell patterning. PMID:26443676

D/H Ratios of Marine Lipids from Santa Barbara Basin Sediments

NASA Astrophysics Data System (ADS)

Li, C.; Sessions, A.; Kinnaman, F.; Valentine, D.

2006-12-01

With the early successful application of compound-specific D/H analyses to reconstructing paleoclimate records, most subsequent research has focused on understanding organic D/H fractionations in terrestrial environments. Thus we still know very little about natural D/H variations in lipids derived from marine organisms, or indeed if any such variations exist. We have therefore conducted an extensive survey of lipid δD values in two sediment cores collected in the Santa Barbara Basin. These data allow us to examine 1) variations between the lipid products of different organisms, 2) down-core variations due to diagenesis, and 3) differences between sediments deposited under oxic or anoxic bottom-water conditions. Our results show that considerable D/H variability between different marine products does exist. δD values of n-alkanes (except n-C35) ranged from -94 to -175 ‰, and exhibit a systematic offset between odd and even carbon numbers. The δD value of n-C35 is anomalous at -220‰. Isotopic compositions of n-alkanols range from -126 to -221 , with a pattern of progressive D depletion with chain length observed for free alcohols. δD values of sterols range from -215 to -309‰, and show no systematic variation with carbon number. However, offsets do exist between the saturated, monounsaturated, and diunsaturated sterols. Sterols as a group are strongly depleted in D relative to the bacterial-derived hopanols (-166 to -232‰), suggesting possible differences in biosynthetic fractionations by bacteria and eukaryotes. Phytol and phytane δD values roughly ranged from -360 to -410‰, while phytanol was systematically enriched at -300 to -340‰. Fatty acids encompassed much greater variability, with dD values ranging from -55 to -270‰. In general, saturated fatty acids are enriched in D relative to their unsaturated analogs, and long-chain (>C24) acids are enriched in D relative to short-chain (

Fish tissue lipid-C:N relationships for correcting δ(13) C values and estimating lipid content in aquatic food-web studies.

PubMed

Hoffman, Joel C; Sierszen, Michael E; Cotter, Anne M

2015-11-15

Normalizing δ(13) C values of animal tissue for lipid content is necessary to accurately interpret food-web relationships from stable isotope analysis. To reduce the effort and expense associated with chemical extraction of lipids, various studies have tested arithmetic mass balance to mathematically normalize δ(13) C values for lipid content; however, the approach assumes that lipid content is related to the tissue C:N ratio. We evaluated two commonly used models for estimating tissue lipid content based on C:N ratio (a mass balance model and a stoichiometric model) by comparing model predictions to measure the lipid content of white muscle tissue. We then determined the effect of lipid model choice on δ(13) C values normalized using arithmetic mass balance. To do so, we used a collection of fish from Lake Superior spanning a wide range in lipid content (5% to 73% lipid). We found that the lipid content was positively related to the bulk muscle tissue C:N ratio. The two different lipid models produced similar estimates of lipid content based on tissue C:N, within 6% for tissue C:N values <7. Normalizing δ(13) C values using an arithmetic mass-balance equation based on either model yielded similar results, with a small bias (<1‰) compared with results based on chemical extraction. Among-species consistency in the relationship between fish muscle tissue C:N ratio and lipid content supports the application of arithmetic mass balance to normalize δ(13) C values for lipid content. The uncertainty associated with both lipid extraction quality and choice of model parameters constrains the achievable precision of normalized δ(13) C values to about ±1.0‰. Published in 2015. This article is a U.S. Government work and is in the public domain in the U.S.A.

Alterations in plasma lipid profile patterns in head and neck cancer and oral precancerous conditions.

PubMed

Patel, P S; Shah, M H; Jha, F P; Raval, G N; Rawal, R M; Patel, M M; Patel, J B; Patel, D D

2004-01-01

The changes in lipid profile have long been associated with cancer because lipids play a key role in maintenance of cell integrity. The present study evaluated alterations in plasma lipid profile in untreated head and neck cancer patients as well as patients with oral precancerous conditions (OPC) and its association with habit of tobacco consumption. This hospital-based case control study included 184 head and neck cancer patients, 153 patients with OPC and 52 controls. Plasma lipids including: (i) Total cholesterol, (ii) LDL cholesterol (LDLC), (iii) HDL cholesterol (HDLC) (iv) VLDL cholesterol (VLDLC) and (v) triglycerides were analysed by spectrophotometric kits. Student's t-test was performed to compare mean values of the parameters. A significant decrease in plasma total cholesterol and HDLC was observed in cancer patients (P=0.008 and P=0.000 respectively) as well as in patients with OPC (P=0.014 and P=0.000, respectively) as compared to the controls. The plasma VLDL and triglycerides levels were significantly lower in cancer patients as compared to the patients with OPC (P=0.04) and controls (P=0.059). The tobacco habituates showed lower plasma lipid levels than the non-habituates. Our data strengthen the evidence of an inverse relationship between plasma lipid levels and head and neck malignancies as well as OPC. The lower levels of plasma cholesterol and other lipid constituents in patients might be due to their increased utilization by neoplastic cells for new membrane biogenesis. The findings strongly warrant an in-depth study of alterations in plasma lipid profile in head neck cancer patients.

Lipid droplet-associated gene expression and chromatin remodelling in LIPASE 5'-upstream region from beginning- to mid-endodormant bud in 'Fuji' apple.

PubMed

Saito, Takanori; Wang, Shanshan; Ohkawa, Katsuya; Ohara, Hitoshi; Ikeura, Hiromi; Ogawa, Yukiharu; Kondo, Satoru

2017-11-01

We found that lipid accumulation in the meristem region and the expression of MdLIP2A, which appears to be regulated by chromatin remodeling, coincided with endodormancy induction in the 'Fuji' apple. In deciduous trees, including apples (Malus × domestica Borkh.), lipid accumulation in the meristem region towards endodormancy induction has been thought to be an important process for the acquisition of cold tolerance. In this study, we conducted histological staining of crude lipids in the meristem region of 'Fuji' apples and found that lipid accumulation coincided with endodormancy induction. Since a major component of lipid bodies (triacylglycerol) is esterified fatty acids, we analysed fatty acid-derived volatile compounds and genes encoding fatty acid-modifying enzymes (MdLOX1A and MdHPL2A); the reduction of lipid breakdown also coincided with endodormancy induction. We then characterised the expression patterns of lipid body-regulatory genes MdOLE1 and MdLIP2A during endodormancy induction and found that the expression of MdLIP2A correlated well with lipid accumulation towards endodormancy induction. Based on these results, we conducted chromatin remodelling studies and localized the cis-element in the 5'-upstream region of MdLIP2A to clarify its regulatory mechanism. Finally, we revealed that chromatin was concentrated - 764 to - 862 bp of the 5'-upstream region of MdLIP2A, which harbours the GARE [gibberellin responsive MYB transcription factor binding site] and CArG [MADS-box transcription factor binding site] motifs-meristem development-related protein-binding sites.

Lipid class and fatty acid composition of a little-known and rarely collected alga Exophyllum wentii Weber-van Bosse from Bali Island, Indonesia.

PubMed

Illijas, Muhammad I; Indy, Jeane R; Yasui, Hajime; Itabashi, Yutaka

2009-01-01

The lipid class and fatty acid composition of a little-known and rarely collected alga Exophyllum wentii from Bali Island, Indonesia were determined for fresh and frozen-thawed samples using thin-layer chromatography, gas-liquid chromatography, and high-performance liquid chromatography. Glycoglycerolipids, which mainly consisted of mongalactosyldiacylglycerols (MGDG) and digalactosyldiacylglycerols (DGDG), were the predominant lipid components, accounting for 67% and 56% of the total polar lipid content in the fresh and frozen-thawed samples, respectively. Phospholipids, including phosphatidylcholines (PC) and phosphatidylglycerols (PG), were detected with lesser amounts in both samples (16-17% of the total polar lipid content). Free fatty acids (FFA), sterols and triacylglycerols (TAG) were also detected in minor quantities; however, the FFA content in the frozen-thawed sample increased to up to 20% of the total lipid content, suggesting that hydrolysis of the membrane lipids had occurred. A crude enzyme preparation from the alga showed activities for hydrolyzing the acyl groups of the phospholipids and glycoglycerolipids. Palmitic acid (16:0) and arachidonic acid (20:4n-6) were the major fatty acids in both the total lipid and in individual polar lipid classes as well as the dominant fatty acids released from the membrane lipids by enzymatic hydrolysis. The high level of 20:4n-6 (29%) in the total lipid and the presence of considerable amounts of PC (11% of the total polar lipid) and PG (6.2%) support classification of E. wentii into the Division Rhodophyta.

Near-infrared spectroscopy of newly developed PEGylated lipids.

PubMed

Bista, Rajan K; Bruch, Reinhard F

2008-11-15

Near-infrared (NIR) spectroscopy has been used to analyze a suite of synthesized PEGylated lipids (1-3) trademarked as QuSomes. The three amphiphiles used in this study, differ in their hydrophobic chain length and contain various units of polyethylene glycol (PEG) head groups. Whilst the spectra of QuSomes show a common pattern, differences in the spectra are observed which enable the lipids to be distinguished. NIR absorption spectra of these new artificial lipids have been recorded in the spectral range of 4800-9000 cm(-1) (approximately 2100-1100 nm) by using a new miniaturized spectrometer based on micro-optical-electro-mechanical systems (MOEMS) technology. Three NIR spectral regions are identified, (a) the high wavenumber region between 6500 and 9000 cm(-1) attributed to the first overtone of the hydroxyl stretching and second overtone of the C-H stretching mode; (b) the 5350-5900 cm(-1) region attributed to first overtone of the C-H stretching mode; and (c) the 4800-5300 cm(-1) region attributed to the combination O-H stretching and second overtone of the C=O stretching mode. For each of these regions, the lipids show distinctive spectra which allow their identification and characterization. NIR spectroscopy is a less used technique which does have great potential for the study of lipids, particularly to examine the behaviour of nanovesicles (liposomes) formed from lipids in aqueous suspensions. The study of such lipids is important since they are used as membrane models and prominent candidate for substance and drug delivery systems.

Computational Functional Analysis of Lipid Metabolic Enzymes.

PubMed

Bagnato, Carolina; Have, Arjen Ten; Prados, María B; Beligni, María V

2017-01-01

The computational analysis of enzymes that participate in lipid metabolism has both common and unique challenges when compared to the whole protein universe. Some of the hurdles that interfere with the functional annotation of lipid metabolic enzymes that are common to other pathways include the definition of proper starting datasets, the construction of reliable multiple sequence alignments, the definition of appropriate evolutionary models, and the reconstruction of phylogenetic trees with high statistical support, particularly for large datasets. Most enzymes that take part in lipid metabolism belong to complex superfamilies with many members that are not involved in lipid metabolism. In addition, some enzymes that do not have sequence similarity catalyze similar or even identical reactions. Some of the challenges that, albeit not unique, are more specific to lipid metabolism refer to the high compartmentalization of the routes, the catalysis in hydrophobic environments and, related to this, the function near or in biological membranes.In this work, we provide guidelines intended to assist in the proper functional annotation of lipid metabolic enzymes, based on previous experiences related to the phospholipase D superfamily and the annotation of the triglyceride synthesis pathway in algae. We describe a pipeline that starts with the definition of an initial set of sequences to be used in similarity-based searches and ends in the reconstruction of phylogenies. We also mention the main issues that have to be taken into consideration when using tools to analyze subcellular localization, hydrophobicity patterns, or presence of transmembrane domains in lipid metabolic enzymes.

Novel analytical methods to assess the chemical and physical properties of liposomes.

PubMed

Kothalawala, Nuwan; Mudalige, Thilak K; Sisco, Patrick; Linder, Sean W

2018-08-01

Liposomes are used in commercial pharmaceutical formulations (PFs) and dietary supplements (DSs) as a carrier vehicle to protect the active ingredient from degradation and to increase the half-life of the injectable. Even as the commercialization of liposomal products has rapidly increased, characterization methodologies to evaluate physical and chemical properties of the liposomal products have not been well-established. Herein we develop rapid methodologies to evaluate chemical and selected physical properties of liposomal formulations. Chemical properties of liposomes are determined by their lipid composition. The lipid composition is evaluated by first screening of the lipids present in the sample using HPLC-ELSD followed by HPLC-MSMS analysis with high mass accuracy (<5 ppm), fragmentation pattern and lipid structure databases searching. Physical properties such as particle size and size distribution were investigated using Tunable Resistive Pulse Sensing (TRPS). The developed methods were used to analyze commercially available PFs and DSs. As results, PFs contain distinct number of lipids as indicated by the manufacture, but DSs were more complicated containing a large number of lipids belonging to different sub-classes. Commercially available liposomes have particles with wide size distribution based on size measurements performed by TRPS. The high mass accuracy as well as identification lipids using multiple fragment ions aided to accurately identify the lipids and differentiate them from other lipophilic molecules. The developed analytical methodologies were successfully adapted to measure the physiochemical properties of commercial liposomes. Copyright © 2018. Published by Elsevier B.V.

The association of dietary patterns and the incidence of insulin resistance after a 3-year follow-up: Tehran Lipid and Glucose Study.

PubMed

Doostvandi, Tayebeh; Bahadoran, Zahra; Mozaffari-Khosravi, Hassan; Tahmasebinejad, Zhaleh; Mirmiran, Parvin; Azizi, Fereidoun

2017-05-01

The aim of this study was to investigate the relationship between major dietary patterns and the risk of insulin resistance (IR) among an urban Iranian population. In this longitudinal study, 802 adult men and women were studied within the framework of Tehran Lipid and Glucose Study. Fasting serum insulin and glucose were measured at baseline and again after a 3-year of followup. The usual dietary intakes were assessed using a validated 168 item semi-quantitative food frequency questionnaire and major dietary patterns were obtained using principal component analysis. Logistic regression models were used to estimate the occurrence of IR across tertiles of dietary patterns with adjustment for potential confounding variables. Mean age of participants was 39.0±11.2 years and 45.5% were men. Three major dietary patterns including the Western, traditional and healthy were extracted, which explained 25.3% of total variance in food intake. The healthy dietary pattern, loaded heavily on intake of vegetable oils, fresh and dried fruits, low-fat dairy, nuts and seeds, was accompanied with a reduced risk of insulin resistance by 51% (OR=0.49, 95% CI=0.30-0.81), and 81% (OR=0.19, 95% CI=0.10-0.36), in the second and third tertile, respectively (p trend=0.001). In the presence of all dietary pattern scores in the logistic regression model, a 45% reduced risk of IR was observed per 1 unit increase in healthy dietary pattern score. These findings confirmed the protective effect of a plant-based, low-fat dietary pattern against the development of insulin resistance as a main risk factor of type 2 diabetes and metabolic disorders.

Bilateral sertoli and interstitial cell tumours in abdominal testes of a goat with polled intersex syndrome (PIS).

PubMed

Canisso, I F; Coffee, L L; Ortved, K; Fubini, S L; Monteagudo, L V; Schlafer, D H; Gilbert, R O

2014-12-01

An 8-year-old, mixed breed, polled goat was presented for evaluation of male-like behaviour. Clinical findings included clitoromegaly, a heavily muscled neck, pronounced beard, and erect dorsal guard hairs, which are phenotypic characteristics commonly observed in intersex animals. Transrectal ultrasonography revealed the presence of two abdominal masses caudolateral to the uterine horns. Serum concentration of estradiol was elevated. Genetic evaluation was compatible with polled intersex syndrome defined by an XX karyotype without a Y chromosome or SRY gene. Based on gross and histologic evaluation, the abdominal masses were determined to be intra-abdominal testes, each of which was effaced by Sertoli cell and interstitial (Leydig) cell tumours. The Sertoli cell tumours (SCTs) represented two unique histologic patterns. Regardless of pattern, neoplastic Sertoli cells were consistently lipid laden and positive for vimentin. Interstitial cell tumours (ICTs) were negative for vimentin. Clinical and histopathologic findings suggest that prolonged exposure to steroids secreted by neoplastic Sertoli cells contributed to virilization. In addition, results from immunohistochemistry indicated that vimentin may be a valuable immunodiagnostic tool for differentiation between interstitial and Sertoli cell tumours in goats. © 2014 Blackwell Verlag GmbH.

In vivo measurement of apolipoprotein E from the brain interstitial fluid using microdialysis

PubMed Central

2013-01-01

Background The APOE4 allele variant is the strongest known genetic risk factor for developing late-onset Alzheimer’s disease. The link between apolipoprotein E (apoE) and Alzheimer’s disease is likely due in large part to the impact of apoE on the metabolism of amyloid β (Aβ) within the brain. Manipulation of apoE levels and lipidation within the brain has been proposed as a therapeutic target for the treatment of Alzheimer’s disease. However, we know little about the dynamic regulation of apoE levels and lipidation within the central nervous system. We have developed an assay to measure apoE levels in the brain interstitial fluid of awake and freely moving mice using large molecular weight cut-off microdialysis probes. Results We were able to recover apoE using microdialysis from human cerebrospinal fluid (CSF) in vitro and mouse brain parenchyma in vivo. Microdialysis probes were inserted into the hippocampus of wild-type mice and interstitial fluid was collected for 36 hours. Levels of apoE within the microdialysis samples were determined by ELISA. The levels of apoE were found to be relatively stable over 36 hours. No apoE was detected in microdialysis samples from apoE KO mice. Administration of the RXR agonist bexarotene increased ISF apoE levels while ISF Aβ levels were decreased. Extrapolation to zero-flow analysis allowed us to determine the absolute recoverable concentration of apoE3 in the brain ISF of apoE3 KI mice. Furthermore, analysis of microdialysis samples by non-denaturing gel electrophoresis determined lipidated apoE particles in microdialysis samples were consistent in size with apoE particles from CSF. Finally, we found that the concentration of apoE in the brain ISF was dependent upon apoE isoform in human apoE KI mice, following the pattern apoE2>apoE3>apoE4. Conclusions We are able to collect lipidated apoE from the brain of awake and freely moving mice and monitor apoE levels over the course of several hours from a single mouse. Our technique enables assessment of brain apoE dynamics under physiological and pathophysiological conditions and in response to therapeutic interventions designed to affect apoE levels and lipidation within the brain. PMID:23601557

Childhood growth and chronic disease: evidence from countries undergoing the nutrition transition.

PubMed

Stein, Aryeh D; Thompson, Angela M; Waters, Ashley

2005-07-01

Evidence is accumulating that the pattern of growth in childhood is associated with development of cardiovascular disease in adulthood, but such evidence comes mostly from developed countries. We conducted a review of studies from countries undergoing the nutrition transition. Five birth cohorts with measures of child growth and outcomes through adolescence were identified, from China, India, Guatemala, Brazil and the Philippines. Across studies there are major differences in data availability and in statistical approaches to modelling child growth and its effects. Nevertheless, generally consistent associations of growth failure in early childhood and development of overweight in later childhood with the risk of elevated blood pressure, glucose, and serum lipids in adulthood were observed. As these cohorts mature they will provide a wealth of critical information on the relation between early life factors and later disease risk, and efforts should be made to ensure ongoing follow-up using standardized approaches and more comprehensive assessments.

The utilization of microbes as a fermentation agent to reduce saponin in Trembesi leaves (Sammanea saman)

NASA Astrophysics Data System (ADS)

Sariri, A. K.; Mulyono, A. M. W.; Tari, A. I. N.

2018-03-01

This objective of this research was to observe the utilization of microbes as a fermentation agent of trembesi leaves that can increase the quality of trembesi leaves as ruminants feed. Before fermentation, trembesi leaves were divided into three treatments. They were control = non-agentic in fermentation, D-An = the addition of Aspergillus niger as fermentation agent, and D-Lp = the addition of Lactobacillus plantarum as fermentation agent. Each treatment experienced five repetitions. The experimental design used a randomized direct pattern group design. The analysis included proximate analysis consisting of water content, crude protein content, crude fiber content, lipid content, mineral content (ash) and saponin content after fermentation. It could be concluded that the utilization of Aspergillus niger and Lactobacillus plantarum in fermentation could decrease saponin content and could increase the nutrient content of trembesi leaves by increasing crude protein content otherwise by decreasing crude fiber content of trembesi leaves.

Coupling of anaerobic waste treatment to produce protein- and lipid-rich bacterial biomass.

PubMed

Steinberg, Lisa M; Kronyak, Rachel E; House, Christopher H

2017-11-01

Future long-term manned space missions will require effective recycling of water and nutrients as part of a life support system. Biological waste treatment is less energy intensive than physicochemical treatment methods, yet anaerobic methanogenic waste treatment has been largely avoided due to slow treatment rates and safety issues concerning methane production. However, methane is generated during atmosphere regeneration on the ISS. Here we propose waste treatment via anaerobic digestion followed by methanotrophic growth of Methylococcus capsulatus to produce a protein- and lipid-rich biomass that can be directly consumed, or used to produce other high-protein food sources such as fish. To achieve more rapid methanogenic waste treatment, we built and tested a fixed-film, flow-through, anaerobic reactor to treat an ersatz wastewater. During steady-state operation, the reactor achieved a 97% chemical oxygen demand (COD) removal rate with an organic loading rate of 1740 g d -1  m -3 and a hydraulic retention time of 12.25 d. The reactor was also tested on three occasions by feeding ca. 500 g COD in less than 12 h, representing 50x the daily feeding rate, with COD removal rates ranging from 56-70%, demonstrating the ability of the reactor to respond to overfeeding events. While investigating the storage of treated reactor effluent at a pH of 12, we isolated a strain of Halomonas desiderata capable of acetate degradation under high pH conditions. We then tested the nutritional content of the alkaliphilic Halomonas desiderata strain, as well as the thermophile Thermus aquaticus, as supplemental protein and lipid sources that grow in conditions that should preclude pathogens. The M. capsulatus biomass consisted of 52% protein and 36% lipids, the H. desiderata biomass consisted of 15% protein and 7% lipids, and the Thermus aquaticus biomass consisted of 61% protein and 16% lipids. This work demonstrates the feasibility of rapid waste treatment in a compact reactor design, and proposes recycling of nutrients back into foodstuffs via heterotrophic (including methanotrophic, acetotrophic, and thermophilic) microbial growth. Copyright © 2017. Published by Elsevier Ltd.

Coupling of anaerobic waste treatment to produce protein- and lipid-rich bacterial biomass

NASA Astrophysics Data System (ADS)

Steinberg, Lisa M.; Kronyak, Rachel E.; House, Christopher H.

2017-11-01

Future long-term manned space missions will require effective recycling of water and nutrients as part of a life support system. Biological waste treatment is less energy intensive than physicochemical treatment methods, yet anaerobic methanogenic waste treatment has been largely avoided due to slow treatment rates and safety issues concerning methane production. However, methane is generated during atmosphere regeneration on the ISS. Here we propose waste treatment via anaerobic digestion followed by methanotrophic growth of Methylococcus capsulatus to produce a protein- and lipid-rich biomass that can be directly consumed, or used to produce other high-protein food sources such as fish. To achieve more rapid methanogenic waste treatment, we built and tested a fixed-film, flow-through, anaerobic reactor to treat an ersatz wastewater. During steady-state operation, the reactor achieved a 97% chemical oxygen demand (COD) removal rate with an organic loading rate of 1740 g d-1 m-3 and a hydraulic retention time of 12.25 d. The reactor was also tested on three occasions by feeding ca. 500 g COD in less than 12 h, representing 50x the daily feeding rate, with COD removal rates ranging from 56-70%, demonstrating the ability of the reactor to respond to overfeeding events. While investigating the storage of treated reactor effluent at a pH of 12, we isolated a strain of Halomonas desiderata capable of acetate degradation under high pH conditions. We then tested the nutritional content of the alkaliphilic Halomonas desiderata strain, as well as the thermophile Thermus aquaticus, as supplemental protein and lipid sources that grow in conditions that should preclude pathogens. The M. capsulatus biomass consisted of 52% protein and 36% lipids, the H. desiderata biomass consisted of 15% protein and 7% lipids, and the Thermus aquaticus biomass consisted of 61% protein and 16% lipids. This work demonstrates the feasibility of rapid waste treatment in a compact reactor design, and proposes recycling of nutrients back into foodstuffs via heterotrophic (including methanotrophic, acetotrophic, and thermophilic) microbial growth.

Multimodal imaging of ocular surface of dry eye subjects

NASA Astrophysics Data System (ADS)

Zhang, Aizhong; Salahura, Gheorghe; Kottaiyan, Ranjini; Yoon, Geunyoung; Aquavella, James V.; Zavislan, James M.

2016-03-01

To study the relationship between the corneal lipid layer and the ocular surface temperature (OST), we conducted a clinical trial for 20 subjects. Subjects were clinically screened prior to the trial. Of the 20 subjects, 15 have Meibomian gland dysfunction (MGD), and 5 have aqueous-deficient dry eye (ADDE). A custom, circularly polarized illumination video tearscope measured the lipid layer thickness of the ocular tear film. A long-wave infrared video camera recorded the dynamic thermal properties of the ocular team film. The results of these two methods were analyzed and compared. Using principal component analysis (PCA) of the lipid layer distribution, we find that the 20 subjects could be categorized into five statistically significant groups, independent of their original clinical classification: thin (6 subjects), medium (5 subjects), medium and homogenous (3 subjects), thick (4 subjects), and very thick (2 subjects) lipids, respectively. We also conducted PCA of the OST data, and recategorized the subjects into two thermal groups by k-means clustering: one includes all ADDE subjects and some MGD subjects; the other includes the remaining MGD subjects. By comparing these two methods, we find that dry eye subjects with thin (<= 40 nm) lipids have significantly lower OST, and a larger OST drop range, potentially due to more evaporation. However, as long as the lipid layer is not thin (> 40 nm), there is no strong correlation between the lipid layer thickness and heterogeneity and the OST patterns.

Yeast MRX deletions have short chronological life span and more triacylglycerols.

PubMed

Kanagavijayan, Dhanabalan; Rajasekharan, Ram; Srinivasan, Malathi

2016-02-01

Saccharomyces cerevisiae is an excellent model organism for lipid research. Here, we have used yeast haploid RAdiation Damage (RAD) deletion strains to study life span and lipid storage patterns. RAD genes are mainly involved in DNA repair mechanism and hence, their deletions have resulted in shorter life span. Viable RAD mutants were screened for non-polar lipid content, and some of the mutants showed significantly high amounts of triacylglycerol (TAG) and steryl ester, besides short chronological life span. Among these, RAD50, MRE11 and XRS2 form a complex, MRX that is involved in homologous recombination that showed an increase in the amount of TAG. Microarray data of single MRX deletions revealed that besides DNA damage signature genes, lipid metabolism genes are also differentially expressed. Lipid biosynthetic genes (LPP1, SLC1) were upregulated and lipid hydrolytic gene (TGL3) was downregulated. We observed that rad50Δ, mre11Δ, xrs2Δ and mrxΔ strains have high number of lipid droplets (LDs) with fragmented mitochondria. These mutants have a short chronological life span compared to wild type. Aged wild-type cells also accumulated TAG with LDs of ∼2.0 μm in diameter. These results suggest that TAG accumulation and big size LDs could be possible markers for premature or normal aging. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A Noninvasive Platform for Imaging and Quantifying Oil Storage in Submillimeter Tobacco Seed1[W][OA

PubMed Central

Fuchs, Johannes; Neuberger, Thomas; Rolletschek, Hardy; Schiebold, Silke; Nguyen, Thuy Ha; Borisjuk, Nikolai; Börner, Andreas; Melkus, Gerd; Jakob, Peter; Borisjuk, Ljudmilla

2013-01-01

While often thought of as a smoking drug, tobacco (Nicotiana spp.) is now considered as a plant of choice for molecular farming and biofuel production. Here, we describe a noninvasive means of deriving both the distribution of lipid and the microtopology of the submillimeter tobacco seed, founded on nuclear magnetic resonance (NMR) technology. Our platform enables counting of seeds inside the intact tobacco capsule to measure seed sizes, to model the seed interior in three dimensions, to quantify the lipid content, and to visualize lipid gradients. Hundreds of seeds can be simultaneously imaged at an isotropic resolution of 25 µm, sufficient to assess each individual seed. The relative contributions of the embryo and the endosperm to both seed size and total lipid content could be assessed. The extension of the platform to a range of wild and cultivated Nicotiana species demonstrated certain evolutionary trends in both seed topology and pattern of lipid storage. The NMR analysis of transgenic tobacco plants with seed-specific ectopic expression of the plastidial phosphoenolpyruvate/phosphate translocator, displayed a trade off between seed size and oil concentration. The NMR-based assay of seed lipid content and topology has a number of potential applications, in particular providing a means to test and optimize transgenic strategies aimed at the manipulation of seed size, seed number, and lipid content in tobacco and other species with submillimeter seeds. PMID:23232144

A comparison of the lung clearance kinetics of solid lipid nanoparticles and liposomes by following the 3H-labelled structural lipids after pulmonary delivery in rats.

PubMed

Haque, Shadabul; Whittaker, Michael; McIntosh, Michelle P; Pouton, Colin W; Phipps, Simon; Kaminskas, Lisa M

2018-04-01

The utility of biodegradable nanosized drug carriers for the local and controlled delivery of therapeutics to the lungs has prompted significant interest in the development of inhalable nanomedicines. Still, little is known about how these systems are cleared from the lungs, including the kinetics of the structural lipids. Most preclinical and clinical studies to date have evaluated the lung clearance of loaded drugs, which in many cases poorly reflects the kinetics of the nanocarrier, or the bulk-labelled particles. This study therefore aimed to describe and compare the pulmonary pharmacokinetic behaviour and patterns of lung clearance of two commonly explored inhalable nanocarriers (anionic ∼150 nm liposomes and solid lipid nanoparticles [SLNs]) in rats by following the 3 H-labelled structural lipids (phosphatidylcholine and tristearin respectively). The data showed that SLNs and liposomes were cleared from the lungs at similar rates, despite SLNs being deposited after intratracheal instillation in the upper respiratory track, and primarily via the mucociliary escalator, but this process was more pronounced for SLNs. Structural lipids were mainly associated with plasma proteins rather than nanocarrier in plasma. The lipids also exhibit prolonged lung exposure and are associated with the lung tissue (rather than BALF) over 2 weeks. Copyright © 2018 Elsevier B.V. All rights reserved.

Interaction of cholesterol-conjugated ionizable amino lipids with biomembranes: lipid polymorphism, structure-activity relationship, and implications for siRNA delivery.

PubMed

Zhang, Jingtao; Fan, Haihong; Levorse, Dorothy A; Crocker, Louis S

2011-08-02

Delivery of siRNA is a major obstacle to the advancement of RNAi as a novel therapeutic modality. Lipid nanoparticles (LNP) consisting of ionizable amino lipids are being developed as an important delivery platform for siRNAs, and significant efforts are being made to understand the structure-activity relationship (SAR) of the lipids. This article uses a combination of small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) to evaluate the interaction between cholesterol-conjugated ionizable amino lipids and biomembranes, focusing on an important area of lipid SAR--the ability of lipids to destabilize membrane bilayer structures and facilitate endosomal escape. In this study, cholesterol-conjugated amino lipids were found to be effective in increasing the order of biomembranes and also highly effective in inducing phase changes in biological membranes in vitro (i.e., the lamellar to inverted hexagonal phase transition). The phase transition temperatures, determined using SAXS and DSC, serve as an indicator for ranking the potency of lipids to destabilize endosomal membranes. It was found that the bilayer disruption ability of amino lipids depends strongly on the amino lipid concentration in membranes. Amino lipids with systematic variations in headgroups, the extent of ionization, tail length, the degree of unsaturation, and tail asymmetry were evaluated for their bilayer disruption ability to establish SAR. Overall, it was found that the impact of these lipid structure changes on their bilayer disruption ability agrees well with the results from a conceptual molecular "shape" analysis. Implications of the findings from this study for siRNA delivery are discussed. The methods reported here can be used to support the SAR screening of cationic lipids for siRNA delivery, and the information revealed through the study of the interaction between cationic lipids and biomembranes will contribute significantly to the design of more efficient siRNA delivery vehicles.

Nanoscale patterning controls inorganic-membrane interface structure

NASA Astrophysics Data System (ADS)

Almquist, Benjamin D.; Verma, Piyush; Cai, Wei; Melosh, Nicholas A.

2011-02-01

The ability to non-destructively integrate inorganic structures into or through biological membranes is essential to realizing full bio-inorganic integration, including arrayed on-chip patch-clamps, drug delivery, and biosensors. Here we explore the role of nanoscale patterning on the strength of biomembrane-inorganic interfaces. AFM measurements show that inorganic probes functionalized with hydrophobic bands with thicknesses complimentary to the hydrophobic lipid bilayer core exhibit strong attachment in the bilayer. As hydrophobic band thickness increases to 2-3 times the bilayer core the interfacial strength decreases, comparable to homogeneously hydrophobic probes. Analytical calculations and molecular dynamics simulations predict a transition between a `fused' interface and a `T-junction' that matches the experimental results, showing lipid disorder and defect formation for thicker bands. These results show that matching biological length scales leads to more intimate bio-inorganic junctions, enabling rational design of non-destructive membrane interfaces.The ability to non-destructively integrate inorganic structures into or through biological membranes is essential to realizing full bio-inorganic integration, including arrayed on-chip patch-clamps, drug delivery, and biosensors. Here we explore the role of nanoscale patterning on the strength of biomembrane-inorganic interfaces. AFM measurements show that inorganic probes functionalized with hydrophobic bands with thicknesses complimentary to the hydrophobic lipid bilayer core exhibit strong attachment in the bilayer. As hydrophobic band thickness increases to 2-3 times the bilayer core the interfacial strength decreases, comparable to homogeneously hydrophobic probes. Analytical calculations and molecular dynamics simulations predict a transition between a `fused' interface and a `T-junction' that matches the experimental results, showing lipid disorder and defect formation for thicker bands. These results show that matching biological length scales leads to more intimate bio-inorganic junctions, enabling rational design of non-destructive membrane interfaces. Electronic supplementary information (ESI) available: Breakthrough rate as a function of force plots for 5 nm, 10 nm and ∞-probes.. See DOI: 10.1039/c0nr00486c

A stable planar bilayer membrane of phospholipid supported by cellulose sheets.

PubMed

Setaka, M; Yamamoto, T; Sato, N; Yano, M; Kwan, T

1982-01-01

A new method is reported for preparing a thin planar membrane of 1,2-distearoylsn-glycero-3-phosphocholine and egg yolk lecithin-cholesterol (molar ratio of 1:1) between a pair of cellulose sheets. This technique, developed from the method of the multilayer planar membrane preparation (Setaka, M., et al. (1979) J. Biochem. 86, 355-362; 1619-1622; (1980) J. Biochem. 88, 1819-1829), consisted of three experimental processes. First, a phospholipid monolayer was prepared at an air-water interface, then taken up on a stretched cellulose sheet. A thin lipid membrane, supported from both sides by cellulose sheets, was constructed by combining two of these lipid monolayer-cellulose sheets. The permeability coefficient of the thin lipid membrane was estimated by removing the effect of two outer cellulose sheets, and this permeability was found to be larger than those of other model membranes of a lipid bilayer, indicating that the present lipid membrane is not a perfect single lipid bilayer. However, certain experimental evidence suggests that the bulk of the phospholipids formed a bilayer between the two cellulose sheets. Since this lipid membrane is particularily stable, larger membranes can be prepared by the present method than other planar bilayer membranes of lipid, which are usually constructed inside a pin hole in a thin teflon sheet.

Flexible Charged Macromolecules on Mixed Fluid Lipid Membranes: Theory and Monte Carlo Simulations

PubMed Central

Tzlil, Shelly; Ben-Shaul, Avinoam

2005-01-01

Fluid membranes containing charged lipids enhance binding of oppositely charged proteins by mobilizing these lipids into the interaction zone, overcoming the concomitant entropic losses due to lipid segregation and lower conformational freedom upon macromolecule adsorption. We study this energetic-entropic interplay using Monte Carlo simulations and theory. Our model system consists of a flexible cationic polyelectrolyte, interacting, via Debye-Hückel and short-ranged repulsive potentials, with membranes containing neutral lipids, 1% tetravalent, and 10% (or 1%) monovalent anionic lipids. Adsorption onto a fluid membrane is invariably stronger than to an equally charged frozen or uniform membrane. Although monovalent lipids may suffice for binding rigid macromolecules, polyvalent counter-lipids (e.g., phosphatidylinositol 4,5 bisphosphate), whose entropy loss upon localization is negligible, are crucial for binding flexible macromolecules, which lose conformational entropy upon adsorption. Extending Rosenbluth's Monte Carlo scheme we directly simulate polymer adsorption on fluid membranes. Yet, we argue that similar information could be derived from a biased superposition of quenched membrane simulations. Using a simple cell model we account for surface concentration effects, and show that the average adsorption probabilities on annealed and quenched membranes coincide at vanishing surface concentrations. We discuss the relevance of our model to the electrostatic-switch mechanism of, e.g., the myristoylated alanine-rich C kinase substrate protein. PMID:16126828

Coral lipids and environmental stress.

PubMed

Harriott, V J

1993-04-01

Environmental monitoring of coral reefs is presently limited by difficulties in recognising coral stress, other than by monitoring coral mortality over time. A recent report described an experiment demonstrating that a measured lipid index declined in shaded corals. The technique described might have application in monitoring coral health, with a decline in coral lipid index as an indicator of coral stress. The application of the technique as a practical monitoring tool was tested for two coral species from the Great Barrier Reef. Consistent with the previous results, lipid index for Pocillopora damicornis initially declined over a period of three weeks in corals maintained in filtered seawater in the dark, indicating possible utilization of lipid stored as energy reserves. However, lipid index subsequently rose to near normal levels. In contrast, lipid index of Acropora formosa increased after four weeks in the dark in filtered seawater. The results showed considerable variability in lipid content between samples from the same colony. Results were also found to be dependent on fixation times and sample weight, introducing potential error into the practical application of the technique. The method as described would be unsuitable for monitoring environmental stress in corals, but the search for a practical method to monitor coral health should continue, given its importance in coral reef management.

Pulmonary lipomatous hemangiopericytoma: report of a rare tumor and comparison with solitary fibrous tumor.

PubMed

Yamazaki, Kazuto; Eyden, Brian P

2007-01-01

Lipomatous hemangiopericytoma is a rare mesenchymal tumor showing areas of lipid-containing cells admixed with a spindle-cell component. Like other hemangiopericytomas, it shows a similar vascular pattern to solitary fibrous tumor and, partly for this reason, it and other hemangiopericytomas have been subsumed into solitary fibrous tumor. The present study provides a comprehensive documentation of a single case of pulmonary lipomatous hemangiopericytoma of the lung, the first to be described at this site, and compares it with solitary fibrous tumor, in terms of clinical, histological, immunohistochemical, ultrastructural, and cytogenetic findings. Apart from the lipid-laden-cell component, pulmonary lipomatous hemangiopericytoma and solitary fibrous tumor were similar histologically. Bcl-2 was positive in both. CD34 was minimally expressed in pulmonary lipomatous hemangiopericytoma, which possessed some non-descriptive intercellular junctions, a feature shared by solitary fibrous tumor, which was CD34 positive. However, one of the latter was rich in gap junctions, a feature consistent with strong connexin (Cx) 43 staining and the existence, hitherto unappreciated, of a CD34/Cx43-positive tumor cell network. In pulmonary lipomatous hemangiopericytoma, chromosomal deletions of 43-44, X, -Y were found. In solitary fibrous tumor, 46, XY, del(13)(q?) abnormalities and abnormalities involving chromosome 10 were frequently observed. These similarities and differences are discussed in the context of the currently favored diagnostic fusion of hemangiopericytoma and solitary fibrous tumor.

Beneficial Effects of Common Bean on Adiposity and Lipid Metabolism.

PubMed

Thompson, Henry J; McGinley, John N; Neil, Elizabeth S; Brick, Mark A

2017-09-09

In developed countries which are at the epicenter of the obesity pandemic, pulse crop consumption is well below recommended levels. In a recent systematic review and meta-analysis of 21 randomized controlled clinical trials, pulse consumption was associated with improved weight control and reduced adiposity, although the underlying mechanisms were a matter of speculation. Common bean ( Phaseolus vulgaris L.) is the most widely consumed pulse crop and was the focus of this investigation. Using outbred genetic models of dietary induced obesity resistance and of dietary induced obesity sensitivity in the rat, the impact of bean consumption was investigated on the efficiency with which consumed food was converted to body mass (food efficiency ratio), body fat accumulation, adipocyte morphometrics, and patterns of protein expression associated with lipid metabolism. Cooked whole bean as well as a commercially prepared cooked bean powders were evaluated. While bean consumption did not affect food efficiency ratio, bean reduced visceral adiposity and adipocyte size in both obesity sensitive and resistant rats. In liver, bean consumption increased carnitine palmitoyl transferase 1, which is the rate limiting step in long chain fatty acid oxidation and also resulted in lower levels of circulating triglycerides. Collectively, our results are consistent with the clinical finding that pulse consumption is anti-obesogenic and indicate that one mechanism by which cooked bean exerts its bioactivity is oxidation of long chain fatty acids.

Draft sequencing and analysis of the genome of pufferfish Takifugu flavidus.

PubMed

Gao, Yang; Gao, Qiang; Zhang, Huan; Wang, Lingling; Zhang, Fuchong; Yang, Chuanyan; Song, Linsheng

2014-12-01

The pufferfish Takifugu flavidus is an important economic species due to its outstanding flavour and high market value. It has been regarded as an excellent model of genetic study for decades as well. In the present study, three mate-pair libraries of T. flavidus genome were sequenced by the SOLiD 4 next-generation sequencing platform, and the draft genome was constructed with the short reads using an assisted assembly strategy. The draft consists of 50,947 scaffolds with an N50 value of 305.7 kb, and the average GC content was 45.2%. The combined length of repetitive sequences was 26.5 Mb, which accounted for 6.87% of the genome, indicating that the compactness of T. flavidus genome was approximative with that of T. rubripes genome. A total of 1,253 non-coding RNA genes and 30,285 protein-encoding genes were assigned to the genome. There were 132,775 and 394 presumptive genes playing roles in the colour pattern variation, the relatively slow growth and the lipid metabolism, respectively. Among them, genes involved in the microtubule-dependent transport system, angiogenesis, decapentaplegic pathway and lipid mobilization were significantly expanded in the T. flavidus genome. This draft genome provides a valuable resource for understanding and improving both fundamental and applied research with pufferfish in the future. © The Author 2014. Published by Oxford University Press on behalf of Kazusa DNA Research Institute.

Time-Series Analyses of Transcriptomes and Proteomes Reveal Molecular Networks Underlying Oil Accumulation in Canola.

PubMed

Wan, Huafang; Cui, Yixin; Ding, Yijuan; Mei, Jiaqin; Dong, Hongli; Zhang, Wenxin; Wu, Shiqi; Liang, Ying; Zhang, Chunyu; Li, Jiana; Xiong, Qing; Qian, Wei

2016-01-01

Understanding the regulation of lipid metabolism is vital for genetic engineering of canola ( Brassica napus L.) to increase oil yield or modify oil composition. We conducted time-series analyses of transcriptomes and proteomes to uncover the molecular networks associated with oil accumulation and dynamic changes in these networks in canola. The expression levels of genes and proteins were measured at 2, 4, 6, and 8 weeks after pollination (WAP). Our results show that the biosynthesis of fatty acids is a dominant cellular process from 2 to 6 WAP, while the degradation mainly happens after 6 WAP. We found that genes in almost every node of fatty acid synthesis pathway were significantly up-regulated during oil accumulation. Moreover, significant expression changes of two genes, acetyl-CoA carboxylase and acyl-ACP desaturase, were detected on both transcriptomic and proteomic levels. We confirmed the temporal expression patterns revealed by the transcriptomic analyses using quantitative real-time PCR experiments. The gene set association analysis show that the biosynthesis of fatty acids and unsaturated fatty acids are the most significant biological processes from 2-4 WAP and 4-6 WAP, respectively, which is consistent with the results of time-series analyses. These results not only provide insight into the mechanisms underlying lipid metabolism, but also reveal novel candidate genes that are worth further investigation for their values in the genetic engineering of canola.

Beneficial Effects of Common Bean on Adiposity and Lipid Metabolism

PubMed Central

McGinley, John N.; Neil, Elizabeth S.; Brick, Mark A.

2017-01-01

In developed countries which are at the epicenter of the obesity pandemic, pulse crop consumption is well below recommended levels. In a recent systematic review and meta-analysis of 21 randomized controlled clinical trials, pulse consumption was associated with improved weight control and reduced adiposity, although the underlying mechanisms were a matter of speculation. Common bean (Phaseolus vulgaris L.) is the most widely consumed pulse crop and was the focus of this investigation. Using outbred genetic models of dietary induced obesity resistance and of dietary induced obesity sensitivity in the rat, the impact of bean consumption was investigated on the efficiency with which consumed food was converted to body mass (food efficiency ratio), body fat accumulation, adipocyte morphometrics, and patterns of protein expression associated with lipid metabolism. Cooked whole bean as well as a commercially prepared cooked bean powders were evaluated. While bean consumption did not affect food efficiency ratio, bean reduced visceral adiposity and adipocyte size in both obesity sensitive and resistant rats. In liver, bean consumption increased carnitine palmitoyl transferase 1, which is the rate limiting step in long chain fatty acid oxidation and also resulted in lower levels of circulating triglycerides. Collectively, our results are consistent with the clinical finding that pulse consumption is anti-obesogenic and indicate that one mechanism by which cooked bean exerts its bioactivity is oxidation of long chain fatty acids. PMID:28891931

Probing membrane permeabilization by the antimicrobial peptide distinctin in mercury-supported biomimetic membranes.

PubMed

Becucci, Lucia; Papini, Martina; Mullen, Daniel; Scaloni, Andrea; Veglia, Gianluigi; Guidelli, Rolando

2011-11-01

The mechanism of membrane permeabilization by the antimicrobial peptide distinctin was investigated by using two different mercury-supported biomimetic membranes, namely a lipid self-assembled monolayer and a lipid bilayer tethered to the mercury surface through a hydrophilic spacer (tethered bilayer lipid membrane: tBLM). Incorporation of distinctin into a lipid monolayer from its aqueous solution yields rapidly ion channels selective toward inorganic cations, such as Tl(+) and Cd(2+). Conversely, its incorporation in a tBLM allows the formation of ion channels permeable to potassium ions only at non-physiological transmembrane potentials, more negative than -340mV. These channels, once formed, are unstable at less negative transmembrane potentials. The kinetics of their formation is consistent with the disruption of distinctin clusters adsorbed on top of the lipid bilayer, incorporation of the resulting monomers and their aggregation into hydrophilic pores by a mechanism of nucleation and growth. Comparing the behavior of distinctin in tBLMs with that in conventional black lipid membranes strongly suggests that distinctin channel formation in lipid bilayer requires the partitioning of distinctin molecules between the two sides of the lipid bilayer. We can tentatively hypothesize that an ion channel is formed when one distinctin cluster on one side of the lipid bilayer matches another one on the opposite side. Copyright © 2011 Elsevier B.V. All rights reserved.

Hansen solubility parameters (HSP) for prescreening formulation of solid lipid nanoparticles (SLN): in vitro testing of curcumin-loaded SLN in MCF-7 and BT-474 cell lines.

PubMed

Doktorovova, Slavomira; Souto, Eliana B; Silva, Amélia M

2018-01-01

Curcumin, a phenolic compound from turmeric rhizome (Curcuma longa), has many interesting pharmacological effects, but shows very low aqueous solubility. Consequently, several drug delivery systems based on polymeric and lipid raw materials have been proposed to increase its bioavailability. Solid lipid nanoparticles (SLN), consisting of solid lipid matrix and a surfactant layer can load poorly water-soluble drugs, such as curcumin, deliver them at defined rates and enhance their intracellular uptake. In the present work, we demonstrate that, despite the drug's affinity to lipids frequently used in SLN production, the curcumin amount loaded in most SLN formulations may be too low to exhibit anticancer properties. The predictive curcumin solubility in solid lipids has been thoroughly analyzed by Hansen solubility parameters, in parallel with the lipid-screening solubility tests for a range of selected lipids. We identified the most suitable lipid materials for curcumin-loaded SLN, producing physicochemically stable particles with high encapsulation efficiency (>90%). Loading capacity of curcumin in SLN allowed preventing the cellular damage caused by cationic SLN on MCF-7 and BT-474 cells but was not sufficient to exhibit drug's anticancer properties. But curcumin-loaded SLN exhibited antioxidant properties, substantiating the conclusions that curcumin's effect in cancer cells is highly dose dependent.

Non-Water-Suppressed 1H MR Spectroscopy with Orientational Prior Knowledge Shows Potential for Separating Intra- and Extramyocellular Lipid Signals in Human Myocardium.

PubMed

Fillmer, Ariane; Hock, Andreas; Cameron, Donnie; Henning, Anke

2017-12-04

Conditions such as type II diabetes are linked with elevated lipid levels in the heart, and significantly increased risk of heart failure; however, metabolic processes underlying the development of cardiac disease in type II diabetes are not fully understood. Here we present a non-invasive method for in vivo investigation of cardiac lipid metabolism: namely, IVS-McPRESS. This technique uses metabolite-cycled, non-water suppressed 1 H cardiac magnetic resonance spectroscopy with prospective and retrospective motion correction. High-quality IVS-McPRESS data acquired from healthy volunteers allowed us to investigate the frequency shift of extramyocellular lipid signals, which depends on the myocardial fibre orientation. Assuming consistent voxel positioning relative to myofibres, the myofibre angle with the magnetic field was derived from the voxel orientation. For separation and individual analysis of intra- and extramyocellular lipid signals, the angle myocardial fibres in the spectroscopy voxel take with the magnetic field should be within ±24.5°. Metabolite and lipid concentrations were analysed with respect to BMI. Significant correlations between BMI and unsaturated fatty acids in intramyocellular lipids, and methylene groups in extramyocellular lipids were found. The proposed IVS-McPRESS technique enables non-invasive investigation of cardiac lipid metabolism and may thus be a useful tool to study healthy and pathological conditions.

Moringa Leaves Prevent Hepatic Lipid Accumulation and Inflammation in Guinea Pigs by Reducing the Expression of Genes Involved in Lipid Metabolism

PubMed Central

Almatrafi, Manal Mused; Vergara-Jimenez, Marcela; Murillo, Ana Gabriela; Norris, Gregory H.; Blesso, Christopher N.; Fernandez, Maria Luz

2017-01-01

To investigate the mechanisms by which Moringa oleifera leaves (ML) modulate hepatic lipids, guinea pigs were allocated to either control (0% ML), 10% Low Moringa (LM) or 15% High Moringa (HM) diets with 0.25% dietary cholesterol to induce hepatic steatosis. After 6 weeks, guinea pigs were sacrificed and liver and plasma were collected to determine plasma lipids, hepatic lipids, cytokines and the expression of genes involved in hepatic cholesterol (CH) and triglyceride (TG) metabolism. There were no differences in plasma lipids among groups. A dose-response effect of ML was observed in hepatic lipids (CH and TG) with the lowest concentrations in the HM group (p < 0.001), consistent with histological evaluation of lipid droplets. Hepatic gene expression of diglyceride acyltransferase-2 and peroxisome proliferator activated receptor-γ, as well as protein concentrations interleukin (IL)-1β and interferon-γ, were lowest in the HM group (p < 0.005). Hepatic gene expression of cluster of differentiation-68 and sterol regulatory element binding protein-1c were 60% lower in both the LM and HM groups compared to controls (p < 0.01). This study demonstrates that ML may prevent hepatic steatosis by affecting gene expression related to hepatic lipids synthesis resulting in lower concentrations of cholesterol and triglycerides and reduced inflammation in the liver. PMID:28640194

Moringa Leaves Prevent Hepatic Lipid Accumulation and Inflammation in Guinea Pigs by Reducing the Expression of Genes Involved in Lipid Metabolism.

PubMed

Almatrafi, Manal Mused; Vergara-Jimenez, Marcela; Murillo, Ana Gabriela; Norris, Gregory H; Blesso, Christopher N; Fernandez, Maria Luz

2017-06-22

To investigate the mechanisms by which Moringa oleifera leaves (ML) modulate hepatic lipids, guinea pigs were allocated to either control (0% ML), 10% Low Moringa (LM) or 15% High Moringa (HM) diets with 0.25% dietary cholesterol to induce hepatic steatosis. After 6 weeks, guinea pigs were sacrificed and liver and plasma were collected to determine plasma lipids, hepatic lipids, cytokines and the expression of genes involved in hepatic cholesterol (CH) and triglyceride (TG) metabolism. There were no differences in plasma lipids among groups. A dose-response effect of ML was observed in hepatic lipids (CH and TG) with the lowest concentrations in the HM group ( p < 0.001), consistent with histological evaluation of lipid droplets. Hepatic gene expression of diglyceride acyltransferase-2 and peroxisome proliferator activated receptor-γ, as well as protein concentrations interleukin (IL)-1β and interferon-γ, were lowest in the HM group ( p < 0.005). Hepatic gene expression of cluster of differentiation-68 and sterol regulatory element binding protein-1c were 60% lower in both the LM and HM groups compared to controls ( p < 0.01). This study demonstrates that ML may prevent hepatic steatosis by affecting gene expression related to hepatic lipids synthesis resulting in lower concentrations of cholesterol and triglycerides and reduced inflammation in the liver.

Fine-mapping of lipid regions in global populations discovers ethnic-specific signals and refines previously identified lipid loci

PubMed Central

Zubair, Niha; Luis Ambite, Jose; Bush, William S.; Kichaev, Gleb; Lu, Yingchang; Manichaikul, Ani; Sheu, Wayne H-H.; Absher, Devin; Assimes, Themistocles L.; Bielinski, Suzette J.; Bottinger, Erwin P.; Buzkova, Petra; Chuang, Lee-Ming; Chung, Ren-Hua; Cochran, Barbara; Dumitrescu, Logan; Gottesman, Omri; Haessler, Jeffrey W.; Haiman, Christopher; Heiss, Gerardo; Hsiung, Chao A.; Hung, Yi-Jen; Hwu, Chii-Min; Juang, Jyh-Ming J.; Le Marchand, Loic; Lee, I-Te; Lee, Wen-Jane; Lin, Li-An; Lin, Danyu; Lin, Shih-Yi; Mackey, Rachel H.; Martin, Lisa W.; Pasaniuc, Bogdan; Peters, Ulrike; Predazzi, Irene; Quertermous, Thomas; Reiner, Alex P.; Robinson, Jennifer; Rotter, Jerome I.; Ryckman, Kelli K.; Schreiner, Pamela J.; Stahl, Eli; Tao, Ran; Tsai, Michael Y.; Waite, Lindsay L.; Wang, Tzung-Dau; Buyske, Steven; Ida Chen, Yii-Der; Cheng, Iona; Crawford, Dana C.; Loos, Ruth J.F.; Rich, Stephen S.; Fornage, Myriam; North, Kari E.; Kooperberg, Charles; Carty, Cara L.

2016-01-01

Abstract Genome-wide association studies have identified over 150 loci associated with lipid traits, however, no large-scale studies exist for Hispanics and other minority populations. Additionally, the genetic architecture of lipid-influencing loci remains largely unknown. We performed one of the most racially/ethnically diverse fine-mapping genetic studies of HDL-C, LDL-C, and triglycerides to-date using SNPs on the MetaboChip array on 54,119 individuals: 21,304 African Americans, 19,829 Hispanic Americans, 12,456 Asians, and 530 American Indians. The majority of signals found in these groups generalize to European Americans. While we uncovered signals unique to racial/ethnic populations, we also observed systematically consistent lipid associations across these groups. In African Americans, we identified three novel signals associated with HDL-C (LPL, APOA5, LCAT) and two associated with LDL-C (ABCG8, DHODH). In addition, using this population, we refined the location for 16 out of the 58 known MetaboChip lipid loci. These results can guide tailored screening efforts, reveal population-specific responses to lipid-lowering medications, and aid in the development of new targeted drug therapies. PMID:28426890

Influence of cationic lipid concentration on properties of lipid–polymer hybrid nanospheres for gene delivery

PubMed Central

Bose, Rajendran JC; Arai, Yoshie; Ahn, Jong Chan; Park, Hansoo; Lee, Soo-Hong

2015-01-01

Nanoparticles have been widely used for nonviral gene delivery. Recently, cationic hybrid nanoparticles consisting of two different materials were suggested as a promising delivery vehicle. In this study, nanospheres with a poly(d,l-lactic-co-glycolic acid) (PLGA) core and cationic lipid shell were prepared, and the effect of cationic lipid concentrations on the properties of lipid polymer hybrid nanocarriers investigated. Lipid–polymer hybrid nanospheres (LPHNSs) were fabricated by the emulsion-solvent evaporation method using different concentrations of cationic lipids and characterized for size, surface charge, stability, plasmid DNA-binding capacity, cytotoxicity, and transfection efficiency. All LPHNSs had narrow size distribution with positive surface charges (ζ-potential 52–60 mV), and showed excellent plasmid DNA-binding capacity. In vitro cytotoxicity measurements with HEK293T, HeLa, HaCaT, and HepG2 cells also showed that LPHNSs exhibited less cytotoxicity than conventional transfection agents, such as Lipofectamine and polyethyleneimine–PLGA. As cationic lipid concentrations increased, the particle size of LPHNSs decreased while their ζ-potential increased. In addition, the in vitro transfection efficiency of LPHNSs increased as lipid concentration increased. PMID:26379434

Lipids of parasitic and saprophytic leptospires.

PubMed

Johnson, R C; Livermore, B P; Walby, J K; Jenkin, H M

1970-09-01

The lipid composition of five parasitic and six saprophytic leptospires was compared. Lipids comprise 18 to 26% of the dry weight of the cells after chloroform-methanol extraction. No residual (bound) lipid was found after acid or alkaline hydrolysis of the extracted residue. The total lipid was composed of 60 to 70% phospholipid, and the remaining lipid was free fatty acids. The phospholipid fraction contained phosphatidylethanolamine as the major component, and phosphatidylglycerol and diphosphatidylglycerol were minor components with traces of lysophatidylethanolamine sometimes found. The major fatty acids of leptospires were hexadecanoic, hexadecenoic, and octadecenoic acids. Both the unusual cis-11-hexadecenoic acid and the more common cis-9-hexadecenoic acid were synthesized by the leptospires. Neither the parasitic nor the saprophytic leptospires can chain elongate fatty acids. However, they were capable of beta-oxidation of fatty acids. Both groups of leptospires desaturate fatty acids by an aerobic pathway. When the parasite canicola was cultivated on octadecanoic acid, 87% of the hexadecenoic acid was the 11 isomer, whereas the saprophyte semeranga consisted of 10% of this isomer. In addition, the saprophytic leptospires contained more tetradecanoic acid than the parasites. No differences were observed in the lipid composition of virulent and avirulent strains of canicola.

Lipids of Parasitic and Saprophytic Leptospires

PubMed Central

Johnson, R. C.; Livermore, B. P.; Walby, Judith K.; Jenkin, H. M.

1970-01-01

The lipid composition of five parasitic and six saprophytic leptospires was compared. Lipids comprise 18 to 26% of the dry weight of the cells after chloroform-methanol extraction. No residual (bound) lipid was found after acid or alkaline hydrolysis of the extracted residue. The total lipid was composed of 60 to 70% phospholipid, and the remaining lipid was free fatty acids. The phospholipid fraction contained phosphatidylethanolamine as the major component, and phosphatidylglycerol and diphosphatidylglycerol were minor components with traces of lysophatidylethanolamine sometimes found. The major fatty acids of leptospires were hexadecanoic, hexadecenoic, and octadecenoic acids. Both the unusual cis-11-hexadecenoic acid and the more common cis-9-hexadecenoic acid were synthesized by the leptospires. Neither the parasitic nor the saprophytic leptospires can chain elongate fatty acids. However, they were capable of β-oxidation of fatty acids. Both groups of leptospires desaturate fatty acids by an aerobic pathway. When the parasite canicola was cultivated on octadecanoic acid, 87% of the hexadecenoic acid was the 11 isomer, whereas the saprophyte semeranga consisted of 10% of this isomer. In addition, the saprophytic leptospires contained more tetradecanoic acid than the parasites. No differences were observed in the lipid composition of virulent and avirulent strains of canicola. PMID:16557833

Lipid reserves of Lesser Scaup (Aythya affinis) migrating across a large landscape are consistent with the "Spring Condition" hypothesis

USGS Publications Warehouse

Anteau, M.J.; Afton, A.D.

2009-01-01

The “spring condition” hypothesis (SCH) states that nutrition during spring migration affects survival, reproductive success, and, ultimately, population size of migratory birds. The North American population of Lesser Scaup (Aythya affinis) has experienced a marked decline, apparently because of poor recruitment. An important prediction of the SCH is that female Lesser Scaup have low lipid reserves during spring migration. We previously reported that lipid reserves and body mass of females collected on migratory stopover areas in northwestern Minnesota in springs 2000–2001 were lower than those on the same areas in the 1980s and markedly lower than those collected at Pool 19 of the Mississippi River in 2000–2001, an important preceding stopover area. However, it was unclear whether these findings represented a site-specific result or a landscape-scale phenomenon. Accordingly, we examined lipid and body mass of 641 female Lesser Scaup migrating across seven eco-physiographic regions of Iowa, Minnesota, and North Dakota during springs 2003–2005. We found that lipids and body mass of females throughout the Upper Midwest were similar to or less than the low values documented in northwestern Minnesota in springs 2000–2001 and markedly lower than those of females at Pool 19 in springs 2000–2001. Accordingly, our results are consistent with a prediction of the SCH, because lipid and body mass of females are low throughout this large landscape, lower than at an important preceding stopover area, and lower than all historical values. Finally, our results suggest the potential for cross-seasonal influences of nutrition on recruitment and that a stronger management focus on spring migration habitats may be necessary for conservation and recovery of declining migratory birds, especially Lesser Scaup.

Ultrasound image texture processing for evaluating fatty liver in peripartal dairy cows

NASA Astrophysics Data System (ADS)

Amin, Viren R.; Bobe, Gerd; Young, Jerry; Ametaj, Burim; Beitz, Donald

2001-07-01

The objective of this work is to characterize the liver ultrasound texture as it changes in diffuse disease of fatty liver. This technology could allow non-invasive diagnosis of fatty liver, a major metabolic disorder in early lactation dairy cows. More than 100 liver biopsies were taken from fourteen dairy cows, as a part of the USDA-funded study for effects of glucagon on prevention and treatment of fatty liver. Up to nine liver biopsies were taken from each cow during peripartal period of seven weeks and total lipid content was determined chemically. Just before each liver biopsy was taken, ultrasonic B-mode images were digitally captured using a 3.5 or 5 MHz transducer. Effort was made to capture images that were non-blurred, void of large blood vessels and multiple echoes, and of consistent texture. From each image, a region-of-interest of size 100-by-100 pixels was processed. Texture parameters were calculated using algorithms such as first and second order statistics, 2D Fourier transformation, co-occurrence matrix, and gradient analysis. Many cows had normal liver (3% to 6% total lipid) and a few had developed fatty liver with total lipid up to 15%. The selected texture parameters showed consistent change with changing lipid content and could potentially be used to diagnose early fatty liver non-invasively. The approach of texture analysis algorithms and initial results on their potential in evaluating total lipid percentage is presented here.

Lipid-Lowering Pharmaceutical Clofibrate Inhibits Human Sweet Taste

PubMed Central

Kochem, Matthew

2017-01-01

T1R2-T1R3 is a heteromeric receptor that binds sugars, high potency sweeteners, and sweet taste blockers. In rodents, T1R2-T1R3 is largely responsible for transducing sweet taste perception. T1R2-T1R3 is also expressed in non-taste tissues, and a growing body of evidence suggests that it helps regulate glucose and lipid metabolism. It was previously shown that clofibric acid, a blood lipid-lowering drug, binds T1R2-T1R3 and inhibits its activity in vitro. The purpose of this study was to determine whether clofibric acid inhibits sweetness perception in humans and is, therefore, a T1R2-T1R3 antagonist in vivo. Fourteen participants rated the sweetness intensity of 4 sweeteners (sucrose, sucralose, Na cyclamate, acesulfame K) across a broad range of concentrations. Each sweetener was prepared in solution neat and in mixture with either clofibric acid or lactisole. Clofibric acid inhibited sweetness of every sweetener. Consistent with competitive binding, inhibition by clofibric acid was diminished with increasing sweetener concentration. This study provides in vivo evidence that the lipid-lowering drug clofibric acid inhibits sweetness perception and is, therefore, a T1R carbohydrate receptor inhibitor. Our results are consistent with previous in vitro findings. Given that T1R2-T1R3 may in part regulate glucose and lipid metabolism, future studies should investigate the metabolic effects of T1R inhibition. PMID:27742692

Toward the establishment of standardized in vitro tests for lipid-based formulations, part 3: understanding supersaturation versus precipitation potential during the in vitro digestion of type I, II, IIIA, IIIB and IV lipid-based formulations.

PubMed

Williams, Hywel D; Sassene, Philip; Kleberg, Karen; Calderone, Marilyn; Igonin, Annabel; Jule, Eduardo; Vertommen, Jan; Blundell, Ross; Benameur, Hassan; Müllertz, Anette; Pouton, Colin W; Porter, Christopher J H

2013-12-01

Recent studies have shown that digestion of lipid-based formulations (LBFs) can stimulate both supersaturation and precipitation. The current study has evaluated the drug, formulation and dose-dependence of the supersaturation - precipitation balance for a range of LBFs. Type I, II, IIIA/B LBFs containing medium-chain (MC) or long-chain (LC) lipids, and lipid-free Type IV LBF incorporating different doses of fenofibrate or tolfenamic acid were digested in vitro in a simulated intestinal medium. The degree of supersaturation was assessed through comparison of drug concentrations in aqueous digestion phases (APDIGEST) during LBF digestion and the equilibrium drug solubility in the same phases. Increasing fenofibrate or tolfenamic acid drug loads (i.e., dose) had negligible effects on LC LBF performance during digestion, but promoted drug crystallization (confirmed by XRPD) from MC and Type IV LBF. Drug crystallization was only evident in instances when the calculated maximum supersaturation ratio (SR(M)) was >3. This threshold SR(M) value was remarkably consistent across all LBF and was also consistent with previous studies with danazol. The maximum supersaturation ratio (SR(M)) provides an indication of the supersaturation 'pressure' exerted by formulation digestion and is strongly predictive of the likelihood of drug precipitation in vitro. This may also prove effective in discriminating the in vivo performance of LBFs.

Phospholipid analogues of Porphyromonas gingivalis.

PubMed

Tavana, A M; Korachi, M; Boote, V; Hull, P S; Love, D N; Drucker, D B

2000-05-01

Porphyromonas has lipids containing hydroxy acids and C16:0 and iso-C15:0 major monocarboxylic acids among others. Nothing is known of its individual phospholipid molecular species. The aim of this study was to determine molecular weights and putative identities of individual phospholipid molecular species extracted from Porphyromonas gingivalis (seven strains), P. asaccharolytica (one strain) and P. endodontalis (two strains). Cultures on Blood-Fastidious Anaerobe Agar were harvested, washed and freeze-dried. Phospholipids were extracted and separated by fast atom bombardment mass spectrometry (FAB MS) in negative-ion mode. Phospholipid classes were also separated by thin layer chromatography (TLC). The major anions in the range m/z 209-299 were consistent with the presence of the C13: 0, C15: 0, C16: 0 and C18: 3 mono-carboxylate anions. Major polar lipid anion peaks in the range m/z 618-961 were consistent with the presence of molecular species of phosphatidylethanolamine, phosphatidylglycerol and with unidentified lipid analogues. Porphyromonas gingivalis differed from comparison strains of other species by having major anions with m/z 932, 946 and 960. Unusually, a feline strain of P. gingivalis had a major peak of m/z 736. Selected anions were studied by tandem FAB MS which revealed that peaks with m/z 653 and 946 did not correspond to commonly occurring classes of polar lipids. They were however, glycerophosphates. It is concluded that the polar lipid analogue profiles obtained with Porphyromonas are quite different from those of the genera Prevotella and Bacteroides but reveal heterogeneity within P. gingivalis.

Lipid Clustering Correlates with Membrane Curvature as Revealed by Molecular Simulations of Complex Lipid Bilayers

PubMed Central

Koldsø, Heidi; Shorthouse, David; Hélie, Jean; Sansom, Mark S. P.

2014-01-01

Cell membranes are complex multicomponent systems, which are highly heterogeneous in the lipid distribution and composition. To date, most molecular simulations have focussed on relatively simple lipid compositions, helping to inform our understanding of in vitro experimental studies. Here we describe on simulations of complex asymmetric plasma membrane model, which contains seven different lipids species including the glycolipid GM3 in the outer leaflet and the anionic lipid, phosphatidylinositol 4,5-bisphophate (PIP2), in the inner leaflet. Plasma membrane models consisting of 1500 lipids and resembling the in vivo composition were constructed and simulations were run for 5 µs. In these simulations the most striking feature was the formation of nano-clusters of GM3 within the outer leaflet. In simulations of protein interactions within a plasma membrane model, GM3, PIP2, and cholesterol all formed favorable interactions with the model α-helical protein. A larger scale simulation of a model plasma membrane containing 6000 lipid molecules revealed correlations between curvature of the bilayer surface and clustering of lipid molecules. In particular, the concave (when viewed from the extracellular side) regions of the bilayer surface were locally enriched in GM3. In summary, these simulations explore the nanoscale dynamics of model bilayers which mimic the in vivo lipid composition of mammalian plasma membranes, revealing emergent nanoscale membrane organization which may be coupled both to fluctuations in local membrane geometry and to interactions with proteins. PMID:25340788

Parkin is a lipid-responsive regulator of fat uptake in mice and mutant human cells

PubMed Central

Kim, Kye-Young; Stevens, Mark V.; Akter, M. Hasina; Rusk, Sarah E.; Huang, Robert J.; Cohen, Alexandra; Noguchi, Audrey; Springer, Danielle; Bocharov, Alexander V.; Eggerman, Tomas L.; Suen, Der-Fen; Youle, Richard J.; Amar, Marcelo; Remaley, Alan T.; Sack, Michael N.

2011-01-01

It has long been hypothesized that abnormalities in lipid biology contribute to degenerative brain diseases. Consistent with this, emerging epidemiologic evidence links lipid alterations with Parkinson disease (PD), and disruption of lipid metabolism has been found to predispose to α-synuclein toxicity. We therefore investigated whether Parkin, an E3 ubiquitin ligase found to be defective in patients with early onset PD, regulates systemic lipid metabolism. We perturbed lipid levels by exposing Parkin+/+ and Parkin–/– mice to a high-fat and -cholesterol diet (HFD). Parkin–/– mice resisted weight gain, steatohepatitis, and insulin resistance. In wild-type mice, the HFD markedly increased hepatic Parkin levels in parallel with lipid transport proteins, including CD36, Sr-B1, and FABP. These lipid transport proteins were not induced in Parkin–/– mice. The role of Parkin in fat uptake was confirmed by increased oleate accumulation in hepatocytes overexpressing Parkin and decreased uptake in Parkin–/– mouse embryonic fibroblasts and patient cells harboring complex heterozygous mutations in the Parkin-encoding gene PARK2. Parkin conferred this effect, in part, via ubiquitin-mediated stabilization of the lipid transporter CD36. Reconstitution of Parkin restored hepatic fat uptake and CD36 levels in Parkin–/– mice, and Parkin augmented fat accumulation during adipocyte differentiation. These results demonstrate that Parkin is regulated in a lipid-dependent manner and modulates systemic fat uptake via ubiquitin ligase–dependent effects. Whether this metabolic regulation contributes to premature Parkinsonism warrants investigation. PMID:21865652

Genetic architecture of lipid traits changes over time and differs by race: Princeton Lipid Follow-up Study.

PubMed

Woo, Jessica G; Morrison, John A; Stroop, Davis M; Aronson Friedman, Lisa; Martin, Lisa J

2014-07-01

Dyslipidemia is a major risk factor for CVD. Previous studies on lipid heritability have largely focused on white populations assessed after the obesity epidemic. Given secular trends and racial differences in lipid levels, this study explored whether lipid heritability is consistent across time and between races. African American and white nuclear families had fasting lipids measured in the 1970s and 22-30 years later. Heritability was estimated, and bivariate analyses between visits were conducted by race using variance components analysis. A total of 1,454 individuals (age 14.1/40.6 for offspring/parents at baseline; 39.6/66.5 at follow-up) in 373 families (286 white, 87 African American) were included. Lipid trait heritabilities were typically stronger during the 1970s than the 2000s. At baseline, additive genetic variation for LDL was significantly lower in African Americans than whites (P = 0.015). Shared genetic contribution to lipid variability over time was significant in both whites (all P < 0.0001) and African Americans (P ≤ 0.05 for total, LDL, and HDL cholesterol). African American families demonstrated shared environmental contributions to lipid variation over time (all P ≤ 0.05). Lower heritability, lower LDL genetic variance, and durable environmental effects across the obesity epidemic in African American families suggest race-specific approaches are needed to clarify the genetic etiology of lipids. Copyright © 2014 by the American Society for Biochemistry and Molecular Biology, Inc.

Lipid clustering correlates with membrane curvature as revealed by molecular simulations of complex lipid bilayers.

PubMed

Koldsø, Heidi; Shorthouse, David; Hélie, Jean; Sansom, Mark S P

2014-10-01

Cell membranes are complex multicomponent systems, which are highly heterogeneous in the lipid distribution and composition. To date, most molecular simulations have focussed on relatively simple lipid compositions, helping to inform our understanding of in vitro experimental studies. Here we describe on simulations of complex asymmetric plasma membrane model, which contains seven different lipids species including the glycolipid GM3 in the outer leaflet and the anionic lipid, phosphatidylinositol 4,5-bisphophate (PIP2), in the inner leaflet. Plasma membrane models consisting of 1500 lipids and resembling the in vivo composition were constructed and simulations were run for 5 µs. In these simulations the most striking feature was the formation of nano-clusters of GM3 within the outer leaflet. In simulations of protein interactions within a plasma membrane model, GM3, PIP2, and cholesterol all formed favorable interactions with the model α-helical protein. A larger scale simulation of a model plasma membrane containing 6000 lipid molecules revealed correlations between curvature of the bilayer surface and clustering of lipid molecules. In particular, the concave (when viewed from the extracellular side) regions of the bilayer surface were locally enriched in GM3. In summary, these simulations explore the nanoscale dynamics of model bilayers which mimic the in vivo lipid composition of mammalian plasma membranes, revealing emergent nanoscale membrane organization which may be coupled both to fluctuations in local membrane geometry and to interactions with proteins.

Erythrocyte membrane model with explicit description of the lipid bilayer and the spectrin network.

PubMed

Li, He; Lykotrafitis, George

2014-08-05

The membrane of the red blood cell (RBC) consists of spectrin tetramers connected at actin junctional complexes, forming a two-dimensional (2D) sixfold triangular network anchored to the lipid bilayer. Better understanding of the erythrocyte mechanics in hereditary blood disorders such as spherocytosis, elliptocytosis, and especially, sickle cell disease requires the development of a detailed membrane model. In this study, we introduce a mesoscale implicit-solvent coarse-grained molecular dynamics (CGMD) model of the erythrocyte membrane that explicitly describes the phospholipid bilayer and the cytoskeleton, by extending a previously developed two-component RBC membrane model. We show that the proposed model represents RBC membrane with the appropriate bending stiffness and shear modulus. The timescale and self-consistency of the model are established by comparing our results with experimentally measured viscosity and thermal fluctuations of the RBC membrane. Furthermore, we measure the pressure exerted by the cytoskeleton on the lipid bilayer. We find that defects at the anchoring points of the cytoskeleton to the lipid bilayer (as in spherocytes) cause a reduction in the pressure compared with an intact membrane, whereas defects in the dimer-dimer association of a spectrin filament (as in elliptocytes) cause an even larger decrease in the pressure. We conjecture that this finding may explain why the experimentally measured diffusion coefficients of band-3 proteins are higher in elliptocytes than in spherocytes, and higher than in normal RBCs. Finally, we study the effects that possible attractive forces between the spectrin filaments and the lipid bilayer have on the pressure applied on the lipid bilayer by the filaments. We discover that the attractive forces cause an increase in the pressure as they diminish the effect of membrane protein defects. As this finding contradicts with experimental results, we conclude that the attractive forces are moderate and do not impose a complete attachment of the filaments to the lipid bilayer. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Erythrocyte Membrane Model with Explicit Description of the Lipid Bilayer and the Spectrin Network

PubMed Central

Li, He; Lykotrafitis, George

2014-01-01

The membrane of the red blood cell (RBC) consists of spectrin tetramers connected at actin junctional complexes, forming a two-dimensional (2D) sixfold triangular network anchored to the lipid bilayer. Better understanding of the erythrocyte mechanics in hereditary blood disorders such as spherocytosis, elliptocytosis, and especially, sickle cell disease requires the development of a detailed membrane model. In this study, we introduce a mesoscale implicit-solvent coarse-grained molecular dynamics (CGMD) model of the erythrocyte membrane that explicitly describes the phospholipid bilayer and the cytoskeleton, by extending a previously developed two-component RBC membrane model. We show that the proposed model represents RBC membrane with the appropriate bending stiffness and shear modulus. The timescale and self-consistency of the model are established by comparing our results with experimentally measured viscosity and thermal fluctuations of the RBC membrane. Furthermore, we measure the pressure exerted by the cytoskeleton on the lipid bilayer. We find that defects at the anchoring points of the cytoskeleton to the lipid bilayer (as in spherocytes) cause a reduction in the pressure compared with an intact membrane, whereas defects in the dimer-dimer association of a spectrin filament (as in elliptocytes) cause an even larger decrease in the pressure. We conjecture that this finding may explain why the experimentally measured diffusion coefficients of band-3 proteins are higher in elliptocytes than in spherocytes, and higher than in normal RBCs. Finally, we study the effects that possible attractive forces between the spectrin filaments and the lipid bilayer have on the pressure applied on the lipid bilayer by the filaments. We discover that the attractive forces cause an increase in the pressure as they diminish the effect of membrane protein defects. As this finding contradicts with experimental results, we conclude that the attractive forces are moderate and do not impose a complete attachment of the filaments to the lipid bilayer. PMID:25099803

Ca-Mediated Electroformation of Cell-Sized Lipid Vesicles

PubMed Central

Tao, Fei; Yang, Peng

2015-01-01

Cell-sized lipid giant unilamellar vesicles (GUVs) are formed when lipid molecules self-assemble to construct a single bilayer compartment with similar morphology to living cells. The physics of self-assembly process is only generally understood and the size distribution of GUVs tends to be very polydisperse. Herein we report a strategy for the production of controlled size distributions of GUVs by a novel mechanism dissecting the mediation ability of calcium (Ca) on the conventional electroformation of GUVs. We finely construct both of the calcium ion (Ca2+) and calcium carbonate (CaCO3) mineral adsorption layers on a lipid film surface respectively during the electroformation of GUVs. It is found that Ca2+ Slip plane polarized by alternating electric field could induce a pattern of electroosmotic flow across the surface, and thus confine the fusion and growth of GUVs to facilitate the formation of uniform GUVs. The model is further improved by directly using CaCO3 that is in situ formed on a lipid film surface, providing a GUV population with narrow polydispersity. The two models deciphers the new biological function of calcium on the birth of cell-like lipid vesicles, and thus might be potentially relevant to the construction of new model to elucidate the cellular development process. PMID:25950604

Reduction of serum triacylglycerol-rich lipoprotein concentrations in cows with hepatic lipidosis.

PubMed

Herdt, T H; Liesman, J S; Gerloff, B J; Emery, R S

1983-02-01

The hepatic and serum lipid concentrations in 49 dairy cows with displaced abomasum, 7 postpartum cows fasted for 6 days, and 14 healthy postpartum cows were studied. The cows with displaced abomasums were retrospectively allotted to 2 groups: those with greater than 15% liver fat (DAHF) and those with less than 15% liver fat (DALF). Liver total lipid concentrations were high in the DAHF group, exceeding these values in the fasted cows by 30% and in the healthy and DALF cows by 63% on the average. In contrast, the liver phospholipid concentrations were low in the DAHF group, intermediate in the fasted and DALF groups and high in the healthy group. On a group basis, an inverse relationship was observed between serum and liver lipid concentrations. The serum concentrations of both total and dextran-sulfate-precipitable (DSP) lipids were high in the fasted cows and were less in the DALF and healthy cows and in the DAHF cows (lowest). The between-group differences in serum total and serum DSP concentrations of triacylglycerol, cholesterol, and phospholipid followed the same quantitative pattern as the total lipids. However, the relative difference between groups was greater for each of the DSP lipid fractions. These results support the hypothesis that severe hepatic lipidosis in cattle occurs due to impaired hepatic lipoprotein synthesis and secretion.

Microbial lipid production by oleaginous Rhodococci cultured in lignocellulosic autohydrolysates

DOE PAGES

Wei, Zhen; Zeng, Guangming; Huang, Fang; ...

2015-07-04

Metabolic synthesis of single cell oils (SCOs) for biodiesel application by heterotrophic oleaginous microorganisms is being hampered by the high cost of culture media. This study investigated the possibility of using loblolly pine and sweetgum autohydrolysates as economic feedstocks for microbial lipid production by oleaginous Rhodococcus opacus ( R. opacus) PD630 and DSM 1069. Results revealed that when the substrates were detoxified by the removal of inhibitors (such as HMF—hydroxymethyl-furfural), the two strains exhibited viable growth patterns after a short adaptation/lag phase. R. opacus PD630 accumulated as much as 28.6 % of its cell dry weight (CDW) in lipids whilemore » growing on detoxified sweetgum autohydrolysate (DSAH) that translates to 0.25 g/l lipid yield. The accumulation of SCOs reached the level of oleagenicity in DSM 1069 cells (28.3 % of CDW) as well, while being cultured on detoxified pine autohydrolysate (DPAH), with the maximum lipid yield of 0.31 g/l. The composition of the obtained microbial oils varied depending on the substrates provided. These results indicate that lignocellulosic autohydrolysates can be used as low-cost fermentation substrates for microbial lipid production by wild-type R. opacus species. Furthermore, the variety of applications for aqueous liquors from lignocellulosic pretreatment has been expanded, allowing for the further optimization of the integrated biorefinery.« less

Ca-mediated electroformation of cell-sized lipid vesicles.

PubMed

Tao, Fei; Yang, Peng

2015-05-07

Cell-sized lipid giant unilamellar vesicles (GUVs) are formed when lipid molecules self-assemble to construct a single bilayer compartment with similar morphology to living cells. The physics of self-assembly process is only generally understood and the size distribution of GUVs tends to be very polydisperse. Herein we report a strategy for the production of controlled size distributions of GUVs by a novel mechanism dissecting the mediation ability of calcium (Ca) on the conventional electroformation of GUVs. We finely construct both of the calcium ion (Ca(2+)) and calcium carbonate (CaCO3) mineral adsorption layers on a lipid film surface respectively during the electroformation of GUVs. It is found that Ca(2+) Slip plane polarized by alternating electric field could induce a pattern of electroosmotic flow across the surface, and thus confine the fusion and growth of GUVs to facilitate the formation of uniform GUVs. The model is further improved by directly using CaCO3 that is in situ formed on a lipid film surface, providing a GUV population with narrow polydispersity. The two models deciphers the new biological function of calcium on the birth of cell-like lipid vesicles, and thus might be potentially relevant to the construction of new model to elucidate the cellular development process.

Identification of furan fatty acids in the lipids of common carp (Cyprinus carpio L.).

PubMed

Chvalová, Daniela; Špička, Jiří

2016-06-01

Fatty acid (FA) composition was analyzed in muscle and gonad tissues of marketed common carp (Cyprinus carpio). The extracted lipids were separated into four fractions: polar lipids (PL), diacylglycerols, free fatty acids and triacylglycerols (TAG) using thin layer chromatography. FA content within the lipid fractions was determined by gas chromatography with flame ionization detector (GC/FID). The muscle lipids consisted primarily of TAG (96.9% of total FA), while PL were the major component of both male (67.6%) and female gonad (58.6%) lipids. Polyunsaturated fatty acids predominated in PL of all tissues (52.2-55.8% of total FA); monounsaturated fatty acids were the most abundant FA group in TAG of muscle (51.8%) and female gonads (47.8%) whereas high proportion of furan fatty acids (F-acids) (38.2%) was detected in TAG of male gonads. Eight F-acids were identified by gas chromatography-mass spectrometry (GC/MS) in male gonad samples, including less common 12,15-epoxy-13,14-dimethylnonadeca-12,14-dienoic acid with even-numbered alkyl moiety. Copyright © 2016 Elsevier Ltd. All rights reserved.

Glomerular Lesions in Proteinuric Miniature Schnauzer Dogs.

PubMed

Furrow, E; Lees, G E; Brown, C A; Cianciolo, R E

2017-05-01

Miniature Schnauzer dogs are predisposed to idiopathic hypertriglyerceridemia, which increases risk for diseases such as pancreatitis and gallbladder mucocele. Recently, elevated triglyceride concentrations have been associated with proteinuria in this breed, although it is difficult to determine which abnormality is primary. Retrospective review of renal tissue from 27 proteinuric Miniature Schnauzers revealed that 20 dogs had ultrastructural evidence of osmophilic globules consistent with lipid in glomerular tufts. Seven of these dogs had lipid thromboemboli in glomerular capillary loops that distorted their shape and compressed circulating erythrocytes. Triglyceride concentrations were reported in 6 of these 7 dogs, and all were hypertriglyceridemic. In addition, glomerular lipidosis (defined as accumulation of foam cells within peripheral capillary loops) was identified in a single dog. The remaining 12 dogs had smaller amounts of lipid that could only be identified ultrastructurally. Neither signalment data nor clinicopathologic parameters (serum albumin, serum creatinine, urine protein-to-creatinine ratio, and blood pressure) differed among the various types of lipid lesions. During the time course of this study, all dogs diagnosed with glomerular lipid thromboemboli were Miniature Schnauzers, underscoring the importance of recognizing these clear spaces within capillary loops as lipid.

Lipoidal labellar secretions in Maxillaria ruiz & pav. (Orchidaceae).

PubMed

Davies, K L; Turner, M P; Gregg, A

2003-03-01

The labella of Maxillaria acuminata Lindl., M. cerifera Barb. Rodr. and M. notylioglossa Rchb.f., all members of the M. acuminata alliance, produce a viscid wax-like secretion. Histochemical analysis revealed that the chemical composition of the secretion is similar in all three species, consisting largely of lipid and protein. Light microscopy and low-vacuum scanning electron microscopy were used to investigate the secretory process. In a fourth taxon, M. cf. notylioglossa, transmission electron microscopy showed that lipid bodies are associated with smooth endoplasmic reticulum or occur as plastoglobuli within plastids. Lipid bodies vary in appearance and this may reflect differences in chemical composition. They become associated with the plasmalemma and eventually accumulate between the latter and the cell wall. The wall contains no pits or ectodesmata, and it is speculated that lipid passes through the wall as small lipid moieties before eventually reassembling to form lipid globules on the external surface of the cuticle. These globules are able to coalesce forming extensive viscid areas on the labellum. The possible significance of this process to pollination is discussed.

Lipoidal Labellar Secretions in Maxillaria Ruiz & Pav. (Orchidaceae)

PubMed Central

DAVIES, K. L.; TURNER, M. P.; GREGG, A.

2003-01-01

The labella of Maxillaria acuminata Lindl., M. cerifera Barb. Rodr. and M. notylioglossa Rchb.f., all members of the M. acuminata alliance, produce a viscid wax‐like secretion. Histochemical analysis revealed that the chemical composition of the secretion is similar in all three species, consisting largely of lipid and protein. Light microscopy and low‐vacuum scanning electron microscopy were used to investigate the secretory process. In a fourth taxon, M. cf. notylioglossa, transmission electron microscopy showed that lipid bodies are associated with smooth endoplasmic reticulum or occur as plastoglobuli within plastids. Lipid bodies vary in appearance and this may reflect differences in chemical composition. They become associated with the plasmalemma and eventually accumulate between the latter and the cell wall. The wall contains no pits or ectodesmata, and it is speculated that lipid passes through the wall as small lipid moieties before eventually reassembling to form lipid globules on the external surface of the cuticle. These globules are able to coalesce forming extensive viscid areas on the labellum. The possible significance of this process to pollination is discussed. PMID:12588723

Matrix recrystallization for MALDI-MS imaging of maize lipids at high-spatial resolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duenas, Maria Emilia; Carlucci, Laura; Lee, Young Jin

Matrix recrystallization is optimized and applied to improve lipid ion signals in maize embryos and leaves. A systematic study was performed varying solvent and incubation time. During this study, unexpected side reactions were found when methanol was used as a recrystallization solvent, resulting in the formation of a methyl ester of phosphatidic acid. Furthermore, using an optimum recrystallization condition with isopropanol, there is no apparent delocalization demonstrated with a transmission electron microscopy (TEM) pattern and maize leaf images obtained at 10 μm spatial resolution.

Matrix recrystallization for MALDI-MS imaging of maize lipids at high-spatial resolution

DOE PAGES

Duenas, Maria Emilia; Carlucci, Laura; Lee, Young Jin

2016-06-27

Matrix recrystallization is optimized and applied to improve lipid ion signals in maize embryos and leaves. A systematic study was performed varying solvent and incubation time. During this study, unexpected side reactions were found when methanol was used as a recrystallization solvent, resulting in the formation of a methyl ester of phosphatidic acid. Furthermore, using an optimum recrystallization condition with isopropanol, there is no apparent delocalization demonstrated with a transmission electron microscopy (TEM) pattern and maize leaf images obtained at 10 μm spatial resolution.

Matrix Recrystallization for MALDI-MS Imaging of Maize Lipids at High-Spatial Resolution

NASA Astrophysics Data System (ADS)

Dueñas, Maria Emilia; Carlucci, Laura; Lee, Young Jin

2016-09-01

Matrix recrystallization is optimized and applied to improve lipid ion signals in maize embryos and leaves. A systematic study was performed varying solvent and incubation time. During this study, unexpected side reactions were found when methanol was used as a recrystallization solvent, resulting in the formation of a methyl ester of phosphatidic acid. Using an optimum recrystallization condition with isopropanol, there is no apparent delocalization demonstrated with a transmission electron microscopy (TEM) pattern and maize leaf images obtained at 10 μm spatial resolution.

Matrix Recrystallization for MALDI-MS Imaging of Maize Lipids at High-Spatial Resolution.

PubMed

Dueñas, Maria Emilia; Carlucci, Laura; Lee, Young Jin

2016-09-01

Matrix recrystallization is optimized and applied to improve lipid ion signals in maize embryos and leaves. A systematic study was performed varying solvent and incubation time. During this study, unexpected side reactions were found when methanol was used as a recrystallization solvent, resulting in the formation of a methyl ester of phosphatidic acid. Using an optimum recrystallization condition with isopropanol, there is no apparent delocalization demonstrated with a transmission electron microscopy (TEM) pattern and maize leaf images obtained at 10 μm spatial resolution. Graphical Abstract ᅟ.

Direct interaction of Plin2 with lipids on the surface of lipid droplets: a live cell FRET analysis

PubMed Central

McIntosh, Avery L.; Senthivinayagam, Subramanian; Moon, Kenneth C.; Gupta, Shipra; Lwande, Joel S.; Murphy, Cameron C.; Storey, Stephen M.

2012-01-01

Despite increasing awareness of the health risks associated with excess lipid storage in cells and tissues, knowledge of events governing lipid exchange at the surface of lipid droplets remains unclear. To address this issue, fluorescence resonance energy transfer (FRET) was performed to examine live cell interactions of Plin2 with lipids involved in maintaining lipid droplet structure and function. FRET efficiencies (E) between CFP-labeled Plin2 and fluorescently labeled phosphatidylcholine, sphingomyelin, stearic acid, and cholesterol were quantitated on a pixel-by-pixel basis to generate FRET image maps that specified areas with high E (>60%) in lipid droplets. The mean E and the distance R between the probes indicated a high yield of energy transfer and demonstrated molecular distances on the order of 44–57 Å, in keeping with direct molecular contact. In contrast, FRET between CFP-Plin2 and Nile red was not detected, indicating that the CFP-Plin2/Nile red interaction was beyond FRET proximity (>100 Å). An examination of the effect of Plin2 on cellular metabolism revealed that triacylglycerol, fatty acid, and cholesteryl ester content increased while diacylglycerol remained constant in CFP-Plin2-overexpressing cells. Total phospholipids also increased, reflecting increased phosphatidylcholine and sphingomyelin. Consistent with these results, expression levels of enzymes involved in triacylglycerol, cholesteryl ester, and phospholipid synthesis were significantly upregulated in CFP-Plin2-expressing cells while those associated with lipolysis either decreased or were unaffected. Taken together, these data show for the first time that Plin2 interacts directly with lipids on the surface of lipid droplets and influences levels of key enzymes and lipids involved in maintaining lipid droplet structure and function. PMID:22744009

Effects of dissolved oxygen level on cell growth and total lipid accumulation in the cultivation of Rhodotorula glutinis.

PubMed

Yen, Hong-Wei; Zhang, Zhiyong

2011-07-01

The total amount of lipids produced in Rhodotorula glutinis is a subject which has attracted increasing attention due to the potential biodiesel conversion from these microbial oils. The effects of the dissolved oxygen (DO) level in lipid accumulation were examined in this study. Variations of different medium volumes (30, 40 and 50ml) and shaking speed (60, 150 and 210rpm) in the flask trials were adopted to explore the DO effects on lipid production. All of the results revealed that a low DO could retard cell growth, while enhancing lipid accumulation. The 5l-fermentor results also confirm that a low DO (25 ± 10%) batch could have higher lipid content than that of high DO batch (60 ± 10%). Nevertheless, the DO level would not obviously affect the lipid composition profile. Oleic acid (C18:1) was the primary fatty acid in both batches. Due to the slow biomass growth rate resulting from the low DO, a two-stage DO controlled strategy (consisting of a high DO stage and following a low DO stage) was performed to improve the cell growth and lipid accumulation simultaneously. However, the strategy was not successful on the enhancement of total lipid production as compared to other batches. Conclusively, even a low DO could retard cell growth; the total production of lipids in the batch with low DO was higher that of the high DO batch due to the enhancement of lipid accumulation. Therefore, the batch operation of R. glutinis at the low DO was suggested for the purpose of lipid production. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

(13)C-metabolic flux analysis of lipid accumulation in the oleaginous fungus Mucor circinelloides.

PubMed

Zhao, Lina; Zhang, Huaiyuan; Wang, Liping; Chen, Haiqin; Chen, Yong Q; Chen, Wei; Song, Yuanda

2015-12-01

The oleaginous fungus Mucor circinelloides is of industrial interest because it can produce high levels of polyunsaturated fatty acid γ-linolenic acid. M. circinelloides CBS 277.49 is able to accumulate less than 15% of cell dry weight as lipids, while M. circinelloides WJ11 can accumulate lipid up to 36%. In order to better understand the mechanisms behind the differential lipid accumulation in these two strains, tracer experiments with (13)C-glucose were performed with the growth of M. circinelloides and subsequent gas chromatography-mass spectrometric detection of (13)C-patterns in proteinogenic amino acids was carried out to identify the metabolic network topology and estimate intracellular fluxes. Our results showed that the high oleaginous strain WJ11 had higher flux of pentose phosphate pathway and malic enzyme, lower flux in tricarboxylic acid cycle, higher flux in glyoxylate cycle and ATP: citrate lyase, together, it might provide more NADPH and substrate acetyl-CoA for fatty acid synthesis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Highly stable and self-repairing membrane-mimetic 2D nanomaterials assembled from lipid-like peptoids

PubMed Central

Jin, Haibao; Jiao, Fang; Daily, Michael D.; Chen, Yulin; Yan, Feng; Ding, Yan-Huai; Zhang, Xin; Robertson, Ellen J.; Baer, Marcel D.; Chen, Chun-Long

2016-01-01

An ability to develop sequence-defined synthetic polymers that both mimic lipid amphiphilicity for self-assembly of highly stable membrane-mimetic 2D nanomaterials and exhibit protein-like functionality would revolutionize the development of biomimetic membranes. Here we report the assembly of lipid-like peptoids into highly stable, crystalline, free-standing and self-repairing membrane-mimetic 2D nanomaterials through a facile crystallization process. Both experimental and molecular dynamics simulation results show that peptoids assemble into membranes through an anisotropic formation process. We further demonstrated the use of peptoid membranes as a robust platform to incorporate and pattern functional objects through large side-chain diversity and/or co-crystallization approaches. Similar to lipid membranes, peptoid membranes exhibit changes in thickness upon exposure to external stimuli; they can coat surfaces in single layers and self-repair. We anticipate that this new class of membrane-mimetic 2D nanomaterials will provide a robust matrix for development of biomimetic membranes tailored to specific applications. PMID:27402325

Characterisation of the Native Lipid Moiety of Echinococcus granulosus Antigen B

PubMed Central

Obal, Gonzalo; Ramos, Ana Lía; Silva, Valeria; Lima, Analía; Batthyany, Carlos; Bessio, María Inés; Ferreira, Fernando; Salinas, Gustavo; Ferreira, Ana María

2012-01-01

Antigen B (EgAgB) is the most abundant and immunogenic antigen produced by the larval stage (metacestode) of Echinococcus granulosus. It is a lipoprotein, the structure and function of which have not been completely elucidated. EgAgB apolipoprotein components have been well characterised; they share homology with a group of hydrophobic ligand binding proteins (HLBPs) present exclusively in cestode organisms, and consist of different isoforms of 8-kDa proteins encoded by a polymorphic multigene family comprising five subfamilies (EgAgB1 to EgAgB5). In vitro studies have shown that EgAgB apolipoproteins are capable of binding fatty acids. However, the identity of the native lipid components of EgAgB remains unknown. The present work was aimed at characterising the lipid ligands bound to EgAgB in vivo. EgAgB was purified to homogeneity from hydatid cyst fluid and its lipid fraction was extracted using chloroform∶methanol mixtures. This fraction constituted approximately 40–50% of EgAgB total mass. High-performance thin layer chromatography revealed that the native lipid moiety of EgAgB consists of a variety of neutral (mainly triacylglycerides, sterols and sterol esters) and polar (mainly phosphatidylcholine) lipids. Gas-liquid chromatography analysis showed that 16∶0, 18∶0 and 18∶1(n-9) are the most abundant fatty acids in EgAgB. Furthermore, size exclusion chromatography coupled to light scattering demonstrated that EgAgB comprises a population of particles heterogeneous in size, with an average molecular mass of 229 kDa. Our results provide the first direct evidence of the nature of the hydrophobic ligands bound to EgAgB in vivo and indicate that the structure and composition of EgAgB lipoprotein particles are more complex than previously thought, resembling high density plasma lipoproteins. Results are discussed considering what is known on lipid metabolism in cestodes, and taken into account the Echinococcus spp. genomic information regarding both lipid metabolism and the EgAgB gene family. PMID:22616019

Cathepsin-Mediated Cleavage of Peptides from Peptide Amphiphiles Leads to Enhanced Intracellular Peptide Accumulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Acar, Handan; Samaeekia, Ravand; Schnorenberg, Mathew R.

Peptides synthesized in the likeness of their native interaction domain(s) are natural choices to target protein protein interactions (PPIs) due to their fidelity of orthostatic contact points between binding partners. Despite therapeutic promise, intracellular delivery of biofunctional peptides at concentrations necessary for efficacy remains a formidable challenge. Peptide amphiphiles (PAs) provide a facile method of intracellular delivery and stabilization of bioactive peptides. PAs consisting of biofunctional peptide headgroups linked to hydrophobic alkyl lipid-like tails prevent peptide hydrolysis and proteolysis in circulation, and PA monomers are internalized via endocytosis. However, endocytotic sequestration and steric hindrance from the lipid tail are twomore » major mechanisms that limit PA efficacy to target intracellular PPIs. To address these problems, we have constructed a PA platform consisting of cathepsin-B cleavable PAs in which a selective p53-based inhibitory peptide is cleaved from its lipid tail within endosomes, allowing for intracellular peptide accumulation and extracellular recycling of the lipid moiety. We monitor for cleavage and follow individual PA components in real time using a resonance energy transfer (FRET)-based tracking system. Using this platform, components in real time using a Forster we provide a better understanding and quantification of cellular internalization, trafficking, and endosomal cleavage of PAs and of the ultimate fates of each component.« less

Quantitative evaluation of lipid concentration in atherosclerotic plaque phantom by near-infrared multispectral angioscope at wavelengths around 1200 nm

NASA Astrophysics Data System (ADS)

Matsui, Daichi; Ishii, Katsunori; Awazu, Kunio

2015-07-01

Atherosclerosis is a primary cause of critical ischemic diseases like heart infarction or stroke. A method that can provide detailed information about the stability of atherosclerotic plaques is required. We focused on spectroscopic techniques that could evaluate the chemical composition of lipid in plaques. A novel angioscope using multispectral imaging at wavelengths around 1200 nm for quantitative evaluation of atherosclerotic plaques was developed. The angioscope consists of a halogen lamp, an indium gallium arsenide (InGaAs) camera, 3 optical band pass filters transmitting wavelengths of 1150, 1200, and 1300 nm, an image fiber having 0.7 mm outer diameter, and an irradiation fiber which consists of 7 multimode fibers. Atherosclerotic plaque phantoms with 100, 60, 20 vol.% of lipid were prepared and measured by the multispectral angioscope. The acquired datasets were processed by spectral angle mapper (SAM) method. As a result, simulated plaque areas in atherosclerotic plaque phantoms that could not be detected by an angioscopic visible image could be clearly enhanced. In addition, quantitative evaluation of atherosclerotic plaque phantoms based on the lipid volume fractions was performed up to 20 vol.%. These results show the potential of a multispectral angioscope at wavelengths around 1200 nm for quantitative evaluation of the stability of atherosclerotic plaques.

ISOLATION AND CHARACTERIZATION OF LAMELLAR BODIES AND TUBULAR MYELIN FROM RAT LUNG HOMOGENATES

PubMed Central

Gil, Joan; Reiss, Oscar K.

1973-01-01

Three surface-active fractions which differ in their morphology have been isolated from rat lung homogenates by ultracentrifugation in a discontinuous sucrose density gradient. In order of increasing density, the fractions consisted, as shown by electron microscopy, primarily of common myelin figures, lamellar bodies, and tubular myelin figures. The lipid of all three fractions contained approximately 94% polar lipids and 2% cholesterol. In the case of the common myelin figures and the lamellar bodies, the polar lipids consisted of 73% phosphatidylcholines, 9% phosphatidylserines and inositols, and 8% phosphatidylethanolamines. In the case of the tubular myelin figures, the respective percentages were 58, 19, and 5. Over 90% of the fatty acids of the lecithins of all three fractions were saturated. Electrophoresis of the proteins of the fractions in sodium dodecyl sulfate or Triton X-100 revealed that the lamellar bodies and the tubular myelin figures differed in the mobilities of their proteins. The common myelin figures, however, contained proteins from both of the other fractions. These data indicate that, whereas the lipids of the extracellular, alveolar surfactant(s) originate in the lamellar bodies, the proteins arise from another source. It is further postulated that the tubular myelin figures represent a liquid crystalline state of the alveolar surface-active lipoproteins. PMID:4726305

Quantification of fatty acids as methyl esters and phospholipids in cheese samples after separation of triacylglycerides and phospholipids.

PubMed

Hauff, Simone; Vetter, Walter

2009-03-23

Determination of the individual fatty acid composition of neutral- and phospholipids as well as the phospholipid content of dairy food and other foodstuffs are important tasks in life sciences. For these purposes, a method was developed for the separation of lipids (standards of triolein and diacylphosphatidylcholines as well as three cheese samples) by solid-phase extraction using a self-packed column filled with partly deactivated silica. Non-halogenated solvents were used for the elution of the lipid classes. Cyclohexane/ethyl acetate (1:1, v/v) served for the elution of neutral lipids, while polar lipids were eluted with three solvents (ethyl acetate/methanol, methanol, and methanol/water) into one fraction. The separated lipid fractions were transesterified and the individual fatty acids were quantified by using gas chromatography coupled to electron ionization mass spectrometry (GC/EI-MS) in the selected ion monitoring (SIM) mode. The recovery rate for standard phosphatidylcholines was approximately 90% and cross-contamination from neutral lipids was negligible. The method was applied to cheese samples. Quantitative amounts of individual fatty acids in the phospholipid fraction were <0.002-0.29% of total lipids from camembert, <0.002-0.12% of total lipids from mozzarella, and <0.002-0.18% of total lipids in a goat cream cheese. Differences in the fatty acid pattern of neutral and polar lipids were detected. The quantity of the fatty acids determined in the phospholipid fraction was divided by the factor 0.7 in order to convert the fatty acid content into the phospholipid content of the cheese samples. This factor is based on the contribution of 16:0 to dipalmitoylphosphatidylcholine (DPPC). The resulting DPPC equivalents (DPPC(eq)) were found to be representative for the average contribution of fatty acids to all classes of phospholipids in dairy products. Using this approach, the phospholipid content of lipids from mozzarella, camembert, and goat cream cheese was 0.60%, 1.42% and 0.79%, respectively.

Bumble bees regulate their intake of essential protein and lipid pollen macronutrients.

PubMed

Vaudo, A D; Stabler, D; Patch, H M; Tooker, J F; Grozinger, C M; Wright, G A

2016-12-15

Bee population declines are linked to the reduction of nutritional resources due to land-use intensification, yet we know little about the specific nutritional needs of many bee species. Pollen provides bees with their primary source of protein and lipids, but nutritional quality varies widely among host-plant species. Therefore, bees might have adapted to assess resource quality and adjust their foraging behavior to balance nutrition from multiple food sources. We tested the ability of two bumble bee species, Bombus terrestris and Bombus impatiens, to regulate protein and lipid intake. We restricted B. terrestris adults to single synthetic diets varying in protein:lipid ratios (P:L). The bees over-ate protein on low-fat diets and over-ate lipid on high-fat diets to reach their targets of lipid and protein, respectively. The bees survived best on a 10:1 P:L diet; the risk of dying increased as a function of dietary lipid when bees ate diets with lipid contents greater than 5:1 P:L. Hypothesizing that the P:L intake target of adult worker bumble bees was between 25:1 and 5:1, we presented workers from both species with unbalanced but complementary paired diets to determine whether they self-select their diet to reach a specific intake target. Bees consumed similar amounts of proteins and lipids in each treatment and averaged a 14:1 P:L for B. terrestris and 12:1 P:L for B. impatiens These results demonstrate that adult worker bumble bees likely select foods that provide them with a specific ratio of P:L. These P:L intake targets could affect pollen foraging in the field and help explain patterns of host-plant species choice by bumble bees. © 2016. Published by The Company of Biologists Ltd.

Sex differences in lipid profiles and treatment utilization among young adults with acute myocardial infarction: Results from the VIRGO study.

PubMed

Lu, Yuan; Zhou, Shengfan; Dreyer, Rachel P; Caulfield, Michael; Spatz, Erica S; Geda, Mary; Lorenze, Nancy P; Herbert, Peter; D'Onofrio, Gail; Jackson, Elizabeth A; Lichtman, Judith H; Bueno, Héctor; Spertus, John A; Krumholz, Harlan M

2017-01-01

Young women with acute myocardial infarction (AMI) have higher mortality risk than similarly aged men. An adverse lipid profile is an important risk factor for cardiovascular outcomes after AMI, but little is known about whether young women with AMI have a higher-risk lipid pattern than men. We characterized sex differences in lipid profiles and treatment utilization among young adults with AMI. A total of 2,219 adults with AMI (1,494 women) aged 18-55 years were enrolled from 103 hospitals in the United States (2008-2012). Serum lipids and lipoprotein subclasses were measured 1 month after discharge. More than 90% of adults were discharged on a statin, but less than half received a high-intensity dose and 12% stopped taking treatments by 1 month. For both men and women, the median of low-density lipoprotein (LDL) cholesterol was reduced to <100 mg/dL 1 month after discharge for AMI, but high-density lipoprotein (HDL) cholesterol remained <40 mg/dL. Multivariate regression analyses showed that young women had favorable lipoprotein profiles compared with men: women had higher HDL cholesterol and HDL large particle, but lower total cholesterol-to-HDL cholesterol ratio and LDL small particle. Young women with AMI had slightly favorable lipid and lipoprotein profiles compared with men, suggesting that difference in lipid and lipoprotein may not be a major contributor to sex differences in outcomes after AMI. In both men and women, statin remained inadequately used, and low HDL cholesterol level was a major lipid abnormality. Copyright © 2016 Elsevier Inc. All rights reserved.

Enhanced Lipidome Coverage in Shotgun Analyses by using Gas-Phase Fractionation

NASA Astrophysics Data System (ADS)

Nazari, Milad; Muddiman, David C.

2016-11-01

A high resolving power shotgun lipidomics strategy using gas-phase fractionation and data-dependent acquisition (DDA) was applied toward comprehensive characterization of lipids in a hen ovarian tissue in an untargeted fashion. Using this approach, a total of 822 unique lipids across a diverse range of lipid categories and classes were identified based on their MS/MS fragmentation patterns. Classes of glycerophospholipids and glycerolipids, such as glycerophosphocholines (PC), glycerophosphoethanolamines (PE), and triglycerides (TG), are often the most abundant peaks observed in shotgun lipidomics analyses. These ions suppress the signal from low abundance ions and hinder the chances of characterizing low abundant lipids when DDA is used. These issues were circumvented by utilizing gas-phase fractionation, where DDA was performed on narrow m/z ranges instead of a broad m/z range. Employing gas-phase fractionation resulted in an increase in sensitivity by more than an order of magnitude in both positive- and negative-ion modes. Furthermore, the enhanced sensitivity increased the number of lipids identified by a factor of ≈4, and facilitated identification of low abundant lipids from classes such as cardiolipins that are often difficult to observe in untargeted shotgun analyses and require sample-specific preparation steps prior to analysis. This method serves as a resource for comprehensive profiling of lipids from many different categories and classes in an untargeted manner, as well as for targeted and quantitative analyses of individual lipids. Furthermore, this comprehensive analysis of the lipidome can serve as a species- and tissue-specific database for confident identification of other MS-based datasets, such as mass spectrometry imaging.

Chlamydia trachomatis Is Responsible for Lipid Vacuolation in the Amniotic Epithelium of Fetal Gastroschisis.

PubMed

Feldkamp, Marcia L; Ward, Diane M; Pysher, Theodore J; Chambers, Christina T

2017-07-17

Vacuolated amniotic epithelium with lipid droplets in gastroschisis placentas is an unusual finding. Mass spectrometry of lipid droplets identified triglycerides, ester-linked to an unusual pattern of fatty acids. We hypothesize that these findings result from a Chlamydia trachomatis infection during the periconceptional period. The rising incidence of chlamydia infections has paralleled the increasing prevalence of gastroschisis among women less than 25 years of age. Histologically, young women are at greatest risk for a chlamydia infection due to their immature columnar epithelium, the preferential site for attachment of Chlamydia trachomatis infectious particle (elementary body). Chlamydia trachomatis survive in an inclusion, relying on its host to acquire essential nutrients, amino acids, and nucleotides for survival and replication. If essential nutrients are not available, the bacteria cannot replicate and may be trafficked to the lysosome for degradation or remain quiescent, within the inclusion, subverting innate immunologic clearance. Chlamydiae synthesize several lipids (phosphatidylethanolamine, phosphatidylserine, and phosphoatidylglycerol); however, their lipid content reveal eukaryotic lipids (sphingomyelin, cholesterol, phosphatidylcholine, and phosphatidylinositol), evidence that chlamydiae "hijack" host lipids for expansion and replication. The abnormal amniotic epithelial findings are supported by experimental evidence of the trafficking of host lipids into the chlamydiae inclusion. If not lethal, what harm will elementary bodies inflict to the developing embryo? Do these women have a greater pro-inflammatory response to an environmental exposure, whether cigarette smoking, change in partner, or a pathogen? Testing the hypothesis that Chlamydia trachomatis is responsible for amniotic epithelium vacuoles will be a critical first step. Birth Defects Research 109:1003-1010, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Post-Fire Spatial Patterns of Soil Nitrogen Mineralization and Microbial Abundance

PubMed Central

Smithwick, Erica A. H.; Naithani, Kusum J.; Balser, Teri C.; Romme, William H.; Turner, Monica G.

2012-01-01

Stand-replacing fires influence soil nitrogen availability and microbial community composition, which may in turn mediate post-fire successional dynamics and nutrient cycling. However, fires create patchiness at both local and landscape scales and do not result in consistent patterns of ecological dynamics. The objectives of this study were to (1) quantify the spatial structure of microbial communities in forest stands recently affected by stand-replacing fire and (2) determine whether microbial variables aid predictions of in situ net nitrogen mineralization rates in recently burned stands. The study was conducted in lodgepole pine (Pinus contorta var. latifolia) and Engelmann spruce/subalpine fir (Picea engelmannii/Abies lasiocarpa) forest stands that burned during summer 2000 in Greater Yellowstone (Wyoming, USA). Using a fully probabilistic spatial process model and Bayesian kriging, the spatial structure of microbial lipid abundance and fungi-to-bacteria ratios were found to be spatially structured within plots two years following fire (for most plots, autocorrelation range varied from 1.5 to 10.5 m). Congruence of spatial patterns among microbial variables, in situ net N mineralization, and cover variables was evident. Stepwise regression resulted in significant models of in situ net N mineralization and included variables describing fungal and bacterial abundance, although explained variance was low (R2<0.29). Unraveling complex spatial patterns of nutrient cycling and the biotic factors that regulate it remains challenging but is critical for explaining post-fire ecosystem function, especially in Greater Yellowstone, which is projected to experience increased fire frequencies by mid 21st Century. PMID:23226324

Architectures of Lipid Transport Systems for the Bacterial Outer Membrane.

PubMed

Ekiert, Damian C; Bhabha, Gira; Isom, Georgia L; Greenan, Garrett; Ovchinnikov, Sergey; Henderson, Ian R; Cox, Jeffery S; Vale, Ronald D

2017-04-06

How phospholipids are trafficked between the bacterial inner and outer membranes through the hydrophilic space of the periplasm is not known. We report that members of the mammalian cell entry (MCE) protein family form hexameric assemblies with a central channel capable of mediating lipid transport. The E. coli MCE protein, MlaD, forms a ring associated with an ABC transporter complex in the inner membrane. A soluble lipid-binding protein, MlaC, ferries lipids between MlaD and an outer membrane protein complex. In contrast, EM structures of two other E. coli MCE proteins show that YebT forms an elongated tube consisting of seven stacked MCE rings, and PqiB adopts a syringe-like architecture. Both YebT and PqiB create channels of sufficient length to span the periplasmic space. This work reveals diverse architectures of highly conserved protein-based channels implicated in the transport of lipids between the membranes of bacteria and some eukaryotic organelles. Copyright © 2017 Elsevier Inc. All rights reserved.

Uptake and intracellular fate of cholera toxin subunit b-modified mesoporous silica nanoparticle-supported lipid bilayers (aka protocells) in motoneurons.

PubMed

Gonzalez Porras, Maria A; Durfee, Paul; Giambini, Sebastian; Sieck, Gary C; Brinker, C Jeffrey; Mantilla, Carlos B

2018-04-01

Cholera toxin B (CTB) modified mesoporous silica nanoparticle supported lipid bilayers (CTB-protocells) are a promising, customizable approach for targeting therapeutic cargo to motoneurons. In the present study, the endocytic mechanism and intracellular fate of CTB-protocells in motoneurons were examined to provide information for the development of therapeutic application and cargo delivery. Pharmacological inhibitors elucidated CTB-protocells endocytosis to be dependent on the integrity of lipid rafts and macropinocytosis. Using immunofluorescence techniques, live confocal and transmission electron microscopy, CTB-protocells were primarily found in the cytosol, membrane lipid domains and Golgi. There was no difference in the amount of motoneuron activity dependent uptake of CTB-protocells in neuromuscular junctions, consistent with clathrin activation at the axon terminals during low frequency activity. In conclusion, CTB-protocells uptake is mediated principally by lipid rafts and macropinocytosis. Once internalized, CTB-protocells escape lysosomal degradation, and engage biological pathways that are not readily accessible by untargeted delivery methods. Copyright © 2018 Elsevier Inc. All rights reserved.

The gut microbiota modulates host energy and lipid metabolism in mice[S

PubMed Central

Velagapudi, Vidya R.; Hezaveh, Rahil; Reigstad, Christopher S.; Gopalacharyulu, Peddinti; Yetukuri, Laxman; Islam, Sama; Felin, Jenny; Perkins, Rosie; Borén, Jan; Orešič, Matej; Bäckhed, Fredrik

2010-01-01

The gut microbiota has recently been identified as an environmental factor that may promote metabolic diseases. To investigate the effect of gut microbiota on host energy and lipid metabolism, we compared the serum metabolome and the lipidomes of serum, adipose tissue, and liver of conventionally raised (CONV-R) and germ-free mice. The serum metabolome of CONV-R mice was characterized by increased levels of energy metabolites, e.g., pyruvic acid, citric acid, fumaric acid, and malic acid, while levels of cholesterol and fatty acids were reduced. We also showed that the microbiota modified a number of lipid species in the serum, adipose tissue, and liver, with its greatest effect on triglyceride and phosphatidylcholine species. Triglyceride levels were lower in serum but higher in adipose tissue and liver of CONV-R mice, consistent with increased lipid clearance. Our findings show that the gut microbiota affects both host energy and lipid metabolism and highlights its role in the development of metabolic diseases. PMID:20040631

General synthesis and physicochemical characterisation of a series of peptide-mimic lysine-based amino-functionalised lipids.

PubMed

Wölk, Christian; Drescher, Simon; Meister, Annette; Blume, Alfred; Langner, Andreas; Dobner, Bodo

2013-09-16

A series of novel malonic acid diamides (second generation) with two long hydrophobic alkyl chains and an alkaline polar head group was synthesised and characterised as a new class of amino-functionalised lipids. These peptide-mimic lipids are suitable for polynucleotide transfer. The lipids bear a novel backbone consisting of a lysine unit and a malonic acid unit. Six different head-group structures, which vary in size and number of amino groups that can be protonated, were attached to the backbone structure. Furthermore, different alkyl chains were used to build the lipophilic part (namely tetradecyl, hexadecyl, and oleyl). Phase transitions of the new compounds in aqueous dispersions at pH 10 were analysed and discussed in terms of head group and alkyl chain variations. The shape and size of the formed aggregates of selected lipid dispersions were investigated by dynamic light scattering and transmission electron microscopy. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Osmotically Induced Reversible Transitions in Lipid-DNA Mesophases

PubMed Central

Danino, Dganit; Kesselman, Ellina; Saper, Gadiel; Petrache, Horia I.; Harries, Daniel

2009-01-01

We follow the effect of osmotic pressure on isoelectric complexes that self-assemble from mixtures of DNA and mixed neutral and cationic lipids. Using small angle x-ray diffraction and freeze-fracture cryo-electron microscopy, we find that lamellar complexes known to form in aqueous solutions can reversibly transition to hexagonal mesophases under high enough osmotic stress exerted by adding a neutral polymer. Using molecular spacings derived from x-ray diffraction, we estimate the reversible osmotic pressure-volume (Π-V) work needed to induce this transition. We find that the transition free energy is comparable to the work required to elastically bend lipid layers around DNA. Consistent with this, the required work is significantly lowered by an addition of hexanol, which is known to soften lipid bilayers. Our findings not only help to resolve the free-energy contributions associated with lipid-DNA complex formation, but they also demonstrate the importance that osmotic stress can have to the macromolecular phase geometry in realistic biological environments. PMID:19348739

Production of Biodiesel from Lipid of Phytoplankton Chaetoceros calcitrans through Ultrasonic Method

PubMed Central

Kwangdinata, Raymond; Raya, Indah; Zakir, Muhammad

2014-01-01

A research on production of biodiesel from lipid of phytoplankton Chaetoceros calcitrans through ultrasonic method has been done. In this research, we carried out a series of phytoplankton cultures to determine the optimum time of growth and biodiesel synthesis process from phytoplankton lipids. Process of biodiesel synthesis consists of two steps, that is, isolation of phytoplankton lipids and biodiesel synthesis from those lipids. Oil isolation process was carried out by ultrasonic extraction method using ethanol 96%, while biodiesel synthesis was carried out by transesterification reaction using methanol and KOH catalyst under sonication. Weight of biodiesel yield per biomass Chaetoceros calcitrans is 35.35%. Characterization of biodiesel was well carried out in terms of physical properties which are density and viscosity and chemical properties which are FFA content, saponification value, and iodine value. These values meet the American Society for Testing and Materials (ASTM D6751) standard levels, except for the viscosity value which was 1.14 g·cm−3. PMID:24688372

Distinct lipid/lipoprotein profiles and hormonal responsiveness in nine ethnic groups of postmenopausal Asian women: the Pan-Asia Menopause (PAM) study.

PubMed

Taechakraichana, N; Holinka, C F; Haines, C J; Subramaniam, R; Tian, X W; Ausmanas, M K

2007-06-01

Lipid/lipoprotein profiles, among other factors, are associated with risk of cardiovascular disease. Because cardiovascular disease varies in Asian countries, we hypothesized that lipid profiles differ in ethnic groups of postmenopausal Asian women. To add to the limited body of information currently available, we also investigated the effects of estrogen/progestin therapy on lipid/lipoprotein profiles in postmenopausal Asian women. The Pan-Asia Menopause (PAM) study was a prospective, randomized, double-blind clinical trial evaluating 1028 postmenopausal women at 22 investigational centers in 11 Asian countries/territories. Subjects were randomly assigned to one of three doses of continuous combined conjugated estrogens (CE)/medroxyprogesterone acetate (MPA): CE/MPA (in mg/day) = 0.625/2.5, 0.45/1.5 or 0.3/1.5. The treatment period, following baseline evaluations, consisted of six continuous 28-day cycles. Analysis of lipid profiles was a secondary objective of the PAM study. Total cholesterol, low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), very low density cholesterol (VLDC-C), triglycerides and lipoprotein(a) were analyzed at a central laboratory by state-of-the-art methods. Mean concentrations of total cholesterol, LDL-C, VLDL-C and triglycerides differed significantly among the nine ethnic groups of postmenopausal women. This difference was independent of body mass index and age, two factors that also influenced lipid/lipoprotein profiles. Mean HDL-C concentrations also differed, but this difference was influenced by body mass index in a weak interaction. All three doses of CE/MPA significantly lowered total cholesterol. Treatment with the high and middle doses significantly lowered LDL-C, and increased HDL-C, VLDL-C and triglycerides. The high dose produced a significant decrease in lipoprotein(a). The different lipid/lipoprotein profiles in the nine ethnic groups of postmenopausal Asian women evaluated here suggest a relationship to differences in the prevalence of cardiovascular disease reported for different regions in Asia. However, the reported prevalence data on cardiovascular disease morbidity and mortality in the regions corresponding to the nine ethnic groups are insufficient to allow qualitative comparisons with the lipid profiles shown in our study. The lipid/lipoprotein changes in response to estrogen/progestin therapy observed here are consistent with those reported for Western women.

Combined dyslipidemia in childhood.

PubMed

Kavey, Rae-Ellen W

2015-01-01

Combined dyslipidemia (CD) is now the predominant dyslipidemic pattern in childhood, characterized by moderate-to-severe elevation in triglycerides and non-high-density lipoprotein cholesterol (non-HDL-C), minimal elevation in low-density lipoprotein cholesterol (LDL-C), and reduced HDL-C. Nuclear magnetic resonance spectroscopy shows that the CD pattern is represented at the lipid subpopulation level as an increase in small, dense LDL and in overall LDL particle number plus a reduction in total HDL-C and large HDL particles, a highly atherogenic pattern. In youth, CD occurs almost exclusively with obesity and is highly prevalent, seen in more than 40% of obese adolescents. CD in childhood predicts pathologic evidence of atherosclerosis and vascular dysfunction in adolescence and young adulthood, and early clinical cardiovascular events in adult life. There is a tight connection between CD, visceral adiposity, insulin resistance, nonalcoholic fatty liver disease, and the metabolic syndrome, suggesting an integrated pathophysiological response to excessive weight gain. Weight loss, changes in dietary composition, and increases in physical activity have all been shown to improve CD significantly in children and adolescents in short-term studies. Most importantly, even small amounts of weight loss are associated with significant decreases in triglyceride levels and increases in HDL-C levels with improvement in lipid subpopulations. Diet change focused on limitation of simple carbohydrate intake with specific elimination of all sugar-sweetened beverages is very effective. Evidence-based recommendations for initiating diet and activity change are provided. Rarely, drug therapy is needed, and the evidence for drug treatment of CD in childhood is reviewed. Copyright © 2015 National Lipid Association. Published by Elsevier Inc. All rights reserved.

Molecular dynamics simulation of the evolution of hydrophobic defects in one monolayer of a phosphatidylcholine bilayer: relevance for membrane fusion mechanisms.

PubMed Central

Tieleman, D Peter; Bentz, Joe

2002-01-01

The spontaneous formation of the phospholipid bilayer underlies the permeability barrier function of the biological membrane. Tears or defects that expose water to the acyl chains are spontaneously healed by lipid lateral diffusion. However, mechanical barriers, e.g., protein aggregates held in place, could sustain hydrophobic defects. Such defects have been postulated to occur in processes such as membrane fusion. This gives rise to a new question in bilayer structure: What do the lipids do in the absence of lipid lateral diffusion to minimize the free energy of a hydrophobic defect? As a first step to understand this rather fundamental question about bilayer structure, we performed molecular dynamic simulations of up to 10 ns of a planar bilayer from which lipids have been deleted randomly from one monolayer. In one set of simulations, approximately one-half of the lipids in the defect monolayer were restrained to form a mechanical barrier. In the second set, lipids were free to diffuse around. The question was simply whether the defects caused by removing a lipid would aggregate together, forming a large hydrophobic cavity, or whether the membrane would adjust in another way. When there are no mechanical barriers, the lipids in the defect monolayer simply spread out and thin with little effect on the other intact monolayer. In the presence of a mechanical barrier, the behavior of the lipids depends on the size of the defect. When 3 of 64 lipids are removed, the remaining lipids adjust the lower one-half of their chains, but the headgroup structure changes little and the intact monolayer is unaffected. When 6 to 12 lipids are removed, the defect monolayer thins, lipid disorder increases, and lipids from the intact monolayer move toward the defect monolayer. Whereas this is a highly simplified model of a fusion site, this engagement of the intact monolayer into the fusion defect is strikingly consistent with recent results for influenza hemagglutinin mediated fusion. PMID:12202375

Lipogenesis in a wing-polymorphic cricket: Canalization versus morph-specific plasticity as a function of nutritional heterogeneity.

PubMed

Zera, Anthony J; Clark, Rebecca; Behmer, Spence

2016-12-01

The influence of variable nutritional input on life history adaptation is a central, but incompletely understood aspect of life history physiology. The wing-polymorphic cricket, Gryllus firmus, has been extensively studied with respect to the biochemical basis of life history adaptation, in particular, modification of lipid metabolism that underlies the enhanced accumulation of lipid flight fuel in the dispersing morph [LW(f)=long wings with functional flight muscles] relative to the flightless (SW=short-winged) morph. To date, biochemical studies have been undertaken almost exclusively using a single laboratory diet. Thus, the extent to which nutritional heterogeneity, likely experienced in the field, influences this key morph adaptation is unknown. We used the experimental approach of the Geometric Framework for Nutrition and employed 13 diets that differed in the amounts and ratios of protein and carbohydrate to assess how nutrient amount and balance affects morph-specific lipid biosynthesis. Greater lipid biosynthesis and allocation to the soma in the LW(f) compared with the SW morph (1) occurred across the entire protein-carbohydrate landscape and (2) is likely an important contributor to elevated somatic lipid in the LW(f) morph across the entire protein-carbohydrate landscape. Nevertheless, dietary carbohydrate strongly affected lipid biosynthesis in a morph-specific manner (to a greater degree in the LW(f) morph). Lipogenesis in the SW morph may be constrained due to its more limited lipid storage capacity compared to the LW(f) morph. Elevated activity of NADP + -isocitrate dehydrogenase (NADP + -IDH), an enzyme that produces reducing equivalents for lipid biosynthesis, was correlated with and may be an important cause of the increased lipogenesis in the LW(f) morph across most, but not all regions of the protein-carbohydrate landscape. By contrast, ATP-citrate lyase (ACL), an enzyme that catalyzes the first step in the pathway of fatty acid biosynthesis, showed complex morph-specific patterns of activity that were strongly contingent upon diet. Morph-specific patterns of NADP + -IDH and ACL activities across the nutrient landscape were much more complex than expected from previous studies on a single diet. Collectively, our results indicate that the biochemical basis of an important life history adaptation, morph-specific lipogenesis, can be canalized in the face of substantial nutritional heterogeneity. However, in some regions of the protein-carbohydrate landscape, it is strongly modulated in a morph-specific manner. Copyright © 2016 Elsevier Ltd. All rights reserved.

Generalization of the swelling method to measure the intrinsic curvature of lipids

NASA Astrophysics Data System (ADS)

Barragán Vidal, I. A.; Müller, M.

2017-12-01

Via computer simulation of a coarse-grained model of two-component lipid bilayers, we compare two methods of measuring the intrinsic curvatures of the constituting monolayers. The first one is a generalization of the swelling method that, in addition to the assumption that the spontaneous curvature linearly depends on the composition of the lipid mixture, incorporates contributions from its elastic energy. The second method measures the effective curvature-composition coupling between the apposing leaflets of bilayer structures (planar bilayers or cylindrical tethers) to extract the spontaneous curvature. Our findings demonstrate that both methods yield consistent results. However, we highlight that the two-leaflet structure inherent to the latter method has the advantage of allowing measurements for mixed lipid systems up to their critical point of demixing as well as in the regime of high concentration (of either species).

In depth study of acrylamide formation in coffee during roasting: role of sucrose decomposition and lipid oxidation.

PubMed

Kocadağlı, Tolgahan; Göncüoğlu, Neslihan; Hamzalıoğlu, Aytül; Gökmen, Vural

2012-09-01

Coffee, as a source of acrylamide, needs to be investigated in depth to understand the contribution of different precursors. This study aimed to investigate the contributions of sucrose decomposition and lipid oxidation on acrylamide formation in coffee during roasting. Coffee beans and model systems were used to monitor the accumulation of neo-formed carbonyls during heating through sucrose decomposition and lipid oxidation. High resolution mass spectrometry analyses confirmed the formation of 5-hydroxymethylfurfural (HMF) and 3,4-dideoxyosone, which were identified as the major sugar decomposition products in both roasted coffee and model systems. Among others, 2-octenal, 2,4-decadienal, 2,4-heptadienal, 4-hydroxynonenal, and 4,5-epoxy-2-decenal were identified in relatively high quantities in roasted coffee. Formation and elimination of HMF in coffee during roasting had a kinetic pattern similar to those of acrylamide. Its concentration rapidly increased within 10 min followed by an exponential decrease afterward. The amount of lipid oxidation products tended to increase linearly during roasting. It was concluded from the results that roasting formed a pool of neo-formed carbonyls from sucrose decomposition and lipid oxidation, and they play certain role on acrylamide formation in coffee.

Combined thin layer chromatography and gas chromatography with mass spectrometric analysis of lipid classes and fatty acids in malnourished polar bears (Ursus maritimus) which swam to Iceland.

PubMed

Eibler, Dorothee; Krüger, Sabine; Skírnisson, Karl; Vetter, Walter

2017-03-01

Between 2008 and 2011, four polar bears (Ursus maritimus) from the Greenland population swam and/or drifted on ice to Iceland where they arrived in very poor body condition. Body fat resources in these animals were only between 0% and 10% of the body weight (usually 25%). Here we studied the lipid composition in different tissues (adipose tissue if available, liver, kidney and muscle). Lipid classes were determined by thin layer chromatography (TLC) and on-column gas chromatography with mass spectrometry (GC/MS). The fatty acid pattern of total lipids and free fatty acids was analyzed by GC/MS in selected ion monitoring (SIM) mode. Additionally, cholesteryl esters and native fatty acid methyl esters, initially detected as zones in thin layer chromatograms, were enriched by solid phase extraction and quantified by GC/MS. The ratio of free fatty acids to native fatty acid methyl esters could be correlated with the remained body lipids in the polar bears and thus may also serve as a marker for other starving animals or even for humans. Copyright © 2017 Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, C.W.B.; Das Gupta, S.K.; Mattai, J.

Solid-state nuclear magnetic resonance (NMR) spectroscopy and X-ray powder diffraction were used to investigate the mechanism of trehalose (TRE) stabilization of lipid bilayers. Calorimetric investigation of dry TRE-stabilized bilayers reveals a first-order phase transition at temperatures similar to the transition of hydrated lipid bilayers. X-ray diffraction studies show that dry mixtures of TRE and 1,2-dipalmitoyl-sn-phosphatidylcholine (DPPC) have a lamellar structure with excess crystalline TRE being present. {sup 2}H spectra of the choline headgroup show hindered molecular motions as compared to dry DPPC alone, and {sup 13}C spectra of the sn-2-carbonyl show rigid lattice powder patterns indicting very little motion atmore » the headgroup and interfacial regions. Thus, the sugar interacts extensively with the hydrophilic regions of the lipid, from the choline and the phosphate moieties in the headgroup to the glycerol and carbonyls in the interfacial region. The authors postulate that the sugar and the lipid form an extensive hydrogen-bonded network with the sugar acting as a spacer to expand the distance between lipids in the bilayer. The fluididty of the hydrophobic region in the L{sub {lambda}} phase together with the bilayer stabilization at the headgroup contributes to membrane viability in anhydrobiotic organisms.« less

Ultra-large scale AFM of lipid droplet arrays: investigating the ink transfer volume in dip pen nanolithography.

PubMed

Förste, Alexander; Pfirrmann, Marco; Sachs, Johannes; Gröger, Roland; Walheim, Stefan; Brinkmann, Falko; Hirtz, Michael; Fuchs, Harald; Schimmel, Thomas

2015-05-01

There are only few quantitative studies commenting on the writing process in dip-pen nanolithography with lipids. Lipids are important carrier ink molecules for the delivery of bio-functional patters in bio-nanotechnology. In order to better understand and control the writing process, more information on the transfer of lipid material from the tip to the substrate is needed. The dependence of the transferred ink volume on the dwell time of the tip on the substrate was investigated by topography measurements with an atomic force microscope (AFM) that is characterized by an ultra-large scan range of 800 × 800 μm(2). For this purpose arrays of dots of the phospholipid1,2-dioleoyl-sn-glycero-3-phosphocholine were written onto planar glass substrates and the resulting pattern was imaged by large scan area AFM. Two writing regimes were identified, characterized of either a steady decline or a constant ink volume transfer per dot feature. For the steady state ink transfer, a linear relationship between the dwell time and the dot volume was determined, which is characterized by a flow rate of about 16 femtoliters per second. A dependence of the ink transport from the length of pauses before and in between writing the structures was observed and should be taken into account during pattern design when aiming at best writing homogeneity. The ultra-large scan range of the utilized AFM allowed for a simultaneous study of the entire preparation area of almost 1 mm(2), yielding good statistic results.

Transcriptomic Markers of Lipid Synthesis and Deposition in the Arctic Planktonic Copepod Calanus glacialis

NASA Astrophysics Data System (ADS)

Bucklin, A. C.; Tarrant, A. M.; DiVito, K. R.; Reese, B.; O'Neill, R. J.; Knutsen, T.; Wiebe, P. H.

2016-02-01

The zooplankton assemblage of the Arctic Ocean is directly impacted by the rapid climate shifts, including warming, loss of ice cover, and changes in the composition of the pelagic assemblage at all trophic levels. Arctic zooplankton species will likely exhibit the full range of responses, including acclimation, adaptation, biogeographical range shifts, and local extinction. The copepod Calanus glacialis has been characterized as an opportunistic species that can switch between active feeding (on either phytoplankton or ice algae) and use of stored energy reserves, including both long-term stores of wax esters in a lipid sac and more dynamic reservoirs of triglycerides throughout the body. This study examined differential expression of selected genes associated with lipid synthesis and deposition pathways in field-caught specimens of C. glacialis. Samples were collected in shelf and offshore regions north and west of Svalbard (Norway) during an August-September, 2015 cruise of the R/V Helmer-Hanssen associated with the SI_Arctic program. Specimens of C. glacialis were photographed to allow analysis of lipid sac volume, and then flash-frozen in liquid nitrogen for analysis of differential gene expression by quantitative PCR (qPCR). The goal of this effort is to use transcriptomic markers to understand how C. glacialis may respond to warming temperatures and changes in time/space patterns of food availability. Our hypothesis is that C. glacialis may exhibit opportunistic life history patterns and physiological responses that pre-adapt the species to acclimation and/or adaptation to environmental variation associated with climate change in Arctic regions.

Ultra-large scale AFM of lipid droplet arrays: investigating the ink transfer volume in dip pen nanolithography

NASA Astrophysics Data System (ADS)

Förste, Alexander; Pfirrmann, Marco; Sachs, Johannes; Gröger, Roland; Walheim, Stefan; Brinkmann, Falko; Hirtz, Michael; Fuchs, Harald; Schimmel, Thomas

2015-05-01

There are only few quantitative studies commenting on the writing process in dip-pen nanolithography with lipids. Lipids are important carrier ink molecules for the delivery of bio-functional patters in bio-nanotechnology. In order to better understand and control the writing process, more information on the transfer of lipid material from the tip to the substrate is needed. The dependence of the transferred ink volume on the dwell time of the tip on the substrate was investigated by topography measurements with an atomic force microscope (AFM) that is characterized by an ultra-large scan range of 800 × 800 μm2. For this purpose arrays of dots of the phospholipid1,2-dioleoyl-sn-glycero-3-phosphocholine were written onto planar glass substrates and the resulting pattern was imaged by large scan area AFM. Two writing regimes were identified, characterized of either a steady decline or a constant ink volume transfer per dot feature. For the steady state ink transfer, a linear relationship between the dwell time and the dot volume was determined, which is characterized by a flow rate of about 16 femtoliters per second. A dependence of the ink transport from the length of pauses before and in between writing the structures was observed and should be taken into account during pattern design when aiming at best writing homogeneity. The ultra-large scan range of the utilized AFM allowed for a simultaneous study of the entire preparation area of almost 1 mm2, yielding good statistic results.

High-resolution proteomic and lipidomic analysis of exosomes and microvesicles from different cell sources

PubMed Central

Haraszti, Reka A.; Didiot, Marie-Cecile; Sapp, Ellen; Leszyk, John; Shaffer, Scott A.; Rockwell, Hannah E.; Gao, Fei; Narain, Niven R.; DiFiglia, Marian; Kiebish, Michael A.; Aronin, Neil; Khvorova, Anastasia

2016-01-01

Extracellular vesicles (EVs), including exosomes and microvesicles (MVs), are explored for use in diagnostics, therapeutics and drug delivery. However, little is known about the relationship of protein and lipid composition of EVs and their source cells. Here, we report high-resolution lipidomic and proteomic analyses of exosomes and MVs derived by differential ultracentrifugation from 3 different cell types: U87 glioblastoma cells, Huh7 hepatocellular carcinoma cells and human bone marrow-derived mesenchymal stem cells (MSCs). We identified 3,532 proteins and 1,961 lipid species in the screen. Exosomes differed from MVs in several different areas: (a) The protein patterns of exosomes were more likely different from their cells of origin than were the protein patterns of MVs; (b) The proteomes of U87 and Huh7 exosomes were similar to each other but different from the proteomes of MSC exosomes, whereas the lipidomes of Huh7 and MSC exosomes were similar to each other but different from the lipidomes of U87 exosomes; (c) exosomes exhibited proteins of extracellular matrix, heparin-binding, receptors, immune response and cell adhesion functions, whereas MVs were enriched in endoplasmic reticulum, proteasome and mitochondrial proteins. Exosomes and MVs also differed in their types of lipid contents. Enrichment in glycolipids and free fatty acids characterized exosomes, whereas enrichment in ceramides and sphingomyelins characterized MVs. Furthermore, Huh7 and MSC exosomes were specifically enriched in cardiolipins; U87 exosomes were enriched in sphingomyelins. This study comprehensively analyses the protein and lipid composition of exosomes, MVs and source cells in 3 different cell types. PMID:27863537

The “Beta-Clasp” model of apolipoprotein A-I - a lipid-free solution structure determined by electron paramagnetic resonance spectroscopy

PubMed Central

Lagerstedt, Jens O.; Budamagunta, Madhu S.; Liu, Grace S.; DeValle, Nicole C.; Voss, John C.; Oda, Michael N.

2012-01-01

Apolipoprotein A-I (apoA-I) is the major protein component of high density lipoproteins (HDL) and plays a central role in cholesterol metabolism. The lipid-free / lipid-poor form of apoA-I is the preferred substrate for the ATP-binding cassette transporter A1 (ABCA1). The interaction of apoA-I with ABCA1 leads to the formation of cholesterol laden high density lipoprotein (HDL) particles, a key step in reverse cholesterol transport and the maintenance of cholesterol homeostasis. Knowledge of the structure of lipid-free apoA-I is essential to understanding its critical interaction with ABCA1 and the molecular mechanisms underlying HDL biogenesis. We therefore examined the structure of lipid-free apoA-I by electron paramagnetic resonance spectroscopy (EPR). Through site directed spin label EPR, we mapped the secondary structure of apoA-I and identified sites of spin coupling as residues 26, 44, 64, 167, 217 and 226. We capitalize on the fact that lipid-free apoA-I self-associates in an anti-parallel manner in solution. We employed these sites of spin coupling to define the central plane in the dimeric apoA-I complex. Applying both the constraints of dipolar coupling with the EPR-derived pattern of solvent accessibility, we assembled the secondary structure into a tertiary context, providing a solution structure for lipid-free apoA-I. PMID:22245143

Molecular modeling of biomembranes and their complexes with protein transmembrane α-helices

NASA Astrophysics Data System (ADS)

Kuznetsov, Andrey S.; Smirnov, Kirill V.; Antonov, Mikhail Yu.; Nikolaev, Ivan N.; Efremov, Roman G.

2017-11-01

Helical segments are common structural elements of membrane proteins. Dimerization and oligomerization of transmembrane (TM) α-helices provides the framework for spatial structure formation and protein-protein interactions. The membrane itself also takes part in the protein functioning. There are some examples of the mutual influence of the lipid bilayer properties and embedded membrane proteins. This work aims at the detail investigation of protein-lipid interactions using model systems: TM peptides corresponding to native protein segments. Three peptides were considered corresponding to TM domains of human glycophorin A (GpA), epidermal growth factor receptor (EGFR) and proposed TM-segment of human neuraminidase-1 (Neu1). A computational analysis of structural and dynamical properties was performed using molecular dynamics method. Monomers of peptides were considered incorporated into hydrated lipid bilayers. It was confirmed, that all these TM peptides have stable helical conformation in lipid environment, and the mutual adaptation of peptides and membrane was observed. It was shown that incorporation of the peptide into membrane results in the modulation of local and mean structural properties of the bilayer. Each peptide interacts with lipid acyl chains having special binding sites on the surface of central part of α-helix that exist for at least 200 ns. However, lipid acyl chains substitute each other faster occupying the same site. The formation of a special pattern of protein-lipid interactions may modulate the association of TM domains of membrane proteins, so membrane environment should be considered when proposing new substances targeting cell receptors.

Tri-membrane nanoparticles produced by combining liposome fusion and a novel patchwork of bicelles to overcome endosomal and nuclear membrane barriers to cargo delivery.

PubMed

Yamada, Asako; Mitsueda, Asako; Hasan, Mahadi; Ueda, Miho; Hama, Susumu; Warashina, Shota; Nakamura, Takashi; Harashima, Hideyoshi; Kogure, Kentaro

2016-03-01

Membrane fusion is a rational strategy for crossing intracellular membranes that present barriers to liposomal nanocarrier-mediated delivery of plasmid DNA into the nucleus of non-dividing cells, such as dendritic cells. Based on this strategy, we previously developed nanocarriers consisting of a nucleic acid core particle coated with four lipid membranes [Akita, et al., Biomaterials, 2009, 30, 2940-2949]. However, including the endosomal membrane and two nuclear membranes, cells possess three intracellular membranous barriers. Thus, after entering the nucleus, nanoparticles coated with four membranes would still have one lipid membrane remaining, and could impede cargo delivery. Until now, coating a core particle with an odd number of lipid membranes was challenging. To produce nanocarriers with an odd number of lipid membranes, we developed a novel coating method involving lipid nano-discs, also known as bicelles, as a material for packaging DNA in a carrier with an odd number of lipid membranes. In this procedure, bicelles fuse to form an outer coating that resembles a patchwork quilt, which allows the preparation of nanoparticles coated with only three lipid membranes. Moreover, the transfection activity of dendritic cells with these three-membrane nanoparticles was higher than that for nanoparticles coated with four lipid membranes. In summary, we developed novel nanoparticles coated with an odd number of lipid membranes using the novel "patchwork-packaging method" to deliver plasmid DNA into the nucleus via membrane fusion.

Development of solid self-emulsifying drug delivery system (SEDDS) I: use of poloxamer 188 as both solidifying and emulsifying agent for lipids.

PubMed

Shah, Ankita V; Serajuddin, Abu T M

2012-10-01

To develop solid self-emulsifying drug delivery systems (SEDDS) for lipids using poloxamer 188 as both solidifying and emulsifying agents. Mixtures of various lipids with poloxamer 188 and PEG 8000 were prepared at ~75°C. The molten mixtures, with and without dissolved drugs (fenofibrate and probucol), were then cooled to room temperature. When solids formed, they were characterized by powder XRD, DSC, microscopy using cross-polarization and confocal fluorescence techniques, dispersion test in water and particle size analysis of dispersions. When mixed with poloxamer 188 or PEG 8000, lipids consisting of monoesters of fatty acids with glycerol or propylene glycol formed solid systems, but not di- and tri-esters, which showed phase separation. Added to water, the solid systems containing poloxamer 188 started to disperse in water forming oil globules of 200-600 nm. No emulsification of lipids was observed from solids containing PEG 8000, indicating that the surfactant property of poloxamer 188 was responsible for emulsification. Powder XRD, DSC and microscopic examination revealed that poloxamer 188 and PEG 8000 maintained their crystallinity in solid systems, while the lipids were interspersed in between crystalline regions. The drug remained solubilized in the lipid phase. A novel solid SEDDS is developed where the drug can be solubilized in liquid lipids and then the lipidic solution can be converted to solid mass by dispersing into the microstructure of poloxamer 188.

Obstructive sleep apnoea treatment and fasting lipids: a comparative effectiveness study.

PubMed

Keenan, Brendan T; Maislin, Greg; Sunwoo, Bernie Y; Arnardottir, Erna Sif; Jackson, Nicholas; Olafsson, Isleifur; Juliusson, Sigurdur; Schwab, Richard J; Gislason, Thorarinn; Benediktsdottir, Bryndis; Pack, Allan I

2014-08-01

Obstructive sleep apnoea (OSA) is associated with cardiovascular disease. Dyslipidaemia has been implicated as a mechanism linking OSA with atherosclerosis, but no consistent associations with lipids exist for OSA or positive airway pressure treatment. We assessed the relationships between fasting lipid levels and obesity and OSA severity, and explored the impact of positive airway pressure treatment on 2-year fasting lipid level changes. Analyses included moderate-to-severe OSA patients from the Icelandic Sleep Apnoea Cohort. Fasting morning lipids were analysed in 613 untreated participants not on lipid-lowering medications at baseline. Patients were then initiated on positive airway pressure and followed for 2 years. Sub-classification using propensity score quintiles, which aimed to replicate covariate balance associated with randomised trials and, therefore, minimise selection bias and allow causal inference, was used to design the treatment group comparisons. 199 positive airway pressure adherent patients and 118 non-users were identified. At baseline, obesity was positively correlated with triglycerides and negatively correlated with total cholesterol, and low-density and high-density lipoprotein cholesterol. A small correlation was observed between the apnoea/hypopnoea index and high-density lipoprotein cholesterol. No effect of positive airway pressure adherence on 2-year fasting lipid changes was observed. Results do not support the concept of changes in fasting lipids as a primary mechanism for the increased risk of atherosclerotic cardiovascular disease in OSA. ©ERS 2014.

Wheat leaf lipids during heat stress: I. High day and night temperatures result in major lipid alterations.

PubMed

Narayanan, Sruthi; Tamura, Pamela J; Roth, Mary R; Prasad, P V Vara; Welti, Ruth

2016-04-01

Understanding how wheat (Triticum aestivum L.) plants under high temperature (HT) regulate lipid composition is critical to developing climate-resilient varieties. We measured 165 glycerolipids and sterol derivatives under optimum and high day and night temperatures in wheat leaves using electrospray ionization-tandem mass spectrometry. Levels of polar lipid fatty acyl chain unsaturation were lower in both heat-tolerant genotype Ventnor and susceptible genotype Karl 92 under HT, compared with optimum temperature. The lower unsaturation was predominantly because of lower levels of 18:3 acyl chains and higher levels of 18:1 and 16:0 acyl chains. Levels of 18:3-containing triacylglycerols increased threefold/more under HT, consistent with their possible role in sequestering fatty acids during membrane lipid remodelling. Phospholipids containing odd-numbered or oxidized acyl chains accumulated in leaves under HT. Sterol glycosides (SG) and 16:0-acylated sterol glycosides (ASG) were higher under HT than optimum temperatures. Ventnor had lower amounts of phospholipids with oxidized acyl chains under HT and higher amounts of SG and 16:0-ASG than Karl 92. Taken together, the data demonstrate that wheat leaf lipid composition is altered by HT, in which some lipids are particularly responsive to HT, and that two wheat genotypes, chosen for their differing physiological responses to HT, differ in lipid profile under HT. © 2015 John Wiley & Sons Ltd.

Methyl-branched lipids promote the membrane adsorption of α-synuclein by enhancing shallow lipid-packing defects.

PubMed

Garten, Matthias; Prévost, Coline; Cadart, Clotilde; Gautier, Romain; Bousset, Luc; Melki, Ronald; Bassereau, Patricia; Vanni, Stefano

2015-06-28

Alpha-synuclein (AS) is a synaptic protein that is directly involved in Parkinson's disease due to its tendency to form protein aggregates. Since AS aggregation can be dependent on the interactions between the protein and the cell plasma membrane, elucidating the membrane binding properties of AS is of crucial importance to establish the molecular basis of AS aggregation into toxic fibrils. Using a combination of in vitro reconstitution experiments based on Giant Unilamellar Vesicles (GUVs), confocal microscopy and all-atom molecular dynamics simulations, we have investigated the membrane binding properties of AS, with a focus on the relative contribution of hydrophobic versus electrostatic interactions. In contrast with previous observations, we did not observe any binding of AS to membranes containing the ganglioside GM1, even at relatively high GM1 content. AS, on the other hand, showed a stronger affinity for neutral flat membranes consisting of methyl-branched lipids. To rationalize these results, we used all-atom molecular dynamics simulations to investigate the influence of methyl-branched lipids on interfacial membrane properties. We found that methyl-branched lipids promote the membrane adsorption of AS by creating shallow lipid-packing defects to a larger extent than polyunsaturated and monounsaturated lipids. Our findings suggest that methyl-branched lipids may constitute a remarkably adhesive substrate for peripheral proteins that adsorb on membranes via hydrophobic insertions.

Wheat leaf lipids during heat stress: I. High day and night temperatures result in major lipid alterations

PubMed Central

Narayanan, Sruthi; Tamura, Pamela J.; Roth, Mary R.; Vara Prasad, P.V.; Welti, Ruth

2016-01-01

Understanding how wheat (Triticum aestivum L.) plants under high temperature (HT) regulate lipid composition is critical to developing climate-resilient varieties. We measured 165 glycerolipids and sterol derivatives under optimum and high day and night temperatures in wheat leaves using electrospray ionization-tandem mass spectrometry. Levels of polar lipid fatty acyl chain unsaturation were lower in both heat-tolerant genotype Ventnor and susceptible genotype Karl 92 under HT, compared to optimum temperature. The lower unsaturation was predominantly due to lower levels of 18:3 and higher levels of 18:1 and 16:0 acyl chains. Levels of 18:3-containing triacylglycerols increased 3-fold/more under HT, consistent with their possible role in sequestering fatty acids during membrane lipid remodeling. Phospholipids containing odd-numbered or oxidized acyl chains accumulated in leaves under HT. Sterol glycosides (SG) and 16:0-acylated sterol glycosides (ASG) were higher under HT than optimum temperatures. Ventnor had lower amounts of phospholipids with oxidized acyl chains under HT and higher amounts of SG and 16:0-ASG than Karl 92. Taken together, the data demonstrate that wheat leaf lipid composition is altered by HT, that some lipids are particularly responsive to HT, and that two wheat genotypes, chosen for their differing physiological responses to HT, differ in lipid profile under HT. PMID:26436679

Accumulation, metabolism, and food-chain transfer of chlorinated and brominated contaminants in subadult white whales (Delphinapterus leucas) and narwhals (Monodon monoceros) from Svalbard, Norway.

PubMed

Wolkers, H; Lydersen, C; Kovacs, K M; Burkow, I; van Bavel, B

2006-01-01

The concentrations and patterns of polychlorinated biphenyls (PCBs), chlorinated pesticides, and polybrominated diphenyl ethers (PBDEs) were studied in white whales (Delphinapterus leucas) and narwhals (Monodon monoceros) from Svalbard, Norway. In addition, their main food items were included in the study. In the whales, a broad range of pollutants was found in relatively high concentrations. PCBs and pesticides were approximately 3000 and 8000 ng/g lipid, respectively, for white whales and three times higher for narwhals. PBDEs 47 were approximately 70 ng/g lipid for white whales and 170 ng/g lipid for narwhals. Compared with other marine mammals from the same area, contaminant levels are among the highest levels ever measured. These high levels are likely in part because of a decreased capacity to metabolize contaminants. Metabolic indices indicated that most compounds accumulate to the same degree in white whales and narwhals, but for some toxaphenes and chlordanes, narwhals might have a decreased metabolism and consequently a higher accumulation. The three-times-higher contaminant levels in blubber of narwhals was further explained by substantially higher contaminant levels in their more benthic diet. The high levels and broad pattern of accumulating pollutants make white whales and narwhals excellent indicators for a wide range of contaminants in the Arctic.

Combination of 1H nuclear magnetic resonance spectroscopy and principal component analysis to evaluate the lipid fluidity of flutamide-encapsulated lipid nanoemulsions.

PubMed

Takegami, Shigehiko; Ueyama, Keita; Konishi, Atsuko; Kitade, Tatsuya

2018-06-06

The lipid fluidity of various lipid nanoemulsions (LNEs) without and with flutamide (FT) and containing one of two neutral lipids, one of four phosphatidylcholines as a surfactant, and sodium palmitate as a cosurfactant was investigated by the combination of 1 H nuclear magnetic resonance (NMR) spectroscopy and principal component analysis (PCA). In the 1 H NMR spectra, the peaks from the methylene groups of the neutral lipids and surfactants for all LNE preparations showed downfield shifts with increasing temperature from 20 to 60 °C. PCA was applied to the 1 H NMR spectral data obtained for the LNEs. The PCA resulted in a model in which the first two principal components (PCs) extracted 88% of the total spectral variation; the first PC (PC-1) axis and second PC (PC-2) axis accounted for 73 and 15%, respectively, of the total spectral variation. The Score-1 values for PC-1 plotted against temperature revealed the existence of two clusters, which were defined by the neutral lipid of the LNE preparations. Meanwhile, the Score-2 values decreased with rising temperature and reflected the increase in lipid fluidity of each LNE preparation, consistent with fluorescence anisotropy measurements. In addition, the changes of Score-2 values with temperature for LNE preparations with FT were smaller than those for LNE preparations without FT. This indicates that FT encapsulated in LNE particles markedly suppressed the increase in lipid fluidity of LNE particles with rising temperature. Thus, PCA of 1 H NMR spectra will become a powerful tool to analyze the lipid fluidity of lipid nanoparticles. Graphical abstract ᅟ.

Effects of feed quality and quantity on growth, early maturation and smolt development in hatchery-reared landlocked Atlantic salmon Salmo salar.

PubMed

Norrgård, J R; Bergman, E; Greenberg, L A; Schmitz, M

2014-10-01

The effects of feed quality and quantity on growth, early male parr maturation and development of smolt characteristics were studied in hatchery-reared landlocked Atlantic salmon Salmo salar. The fish were subjected to two levels of feed rations and two levels of lipid content from first feeding until release in May of their second year. Salmo salar fed high rations, regardless of lipid content, grew the most and those fed low lipid feed with low rations grew the least. In addition, fish fed low lipid feed had lower body lipid levels than fish fed high lipid feed. Salmo salar from all treatments showed some reduction in condition factor (K) and lipid levels during their second spring. Smolt status was evaluated using both physiological and morphological variables. These results, based on gill Na(+) , K(+) -ATPase (NKA) enzyme activity, saltwater tolerance challenges and visual assessments, were consistent with each other, showing that S. salar from all treatments, except the treatment in which the fish were fed low rations with low lipid content, exhibited characteristics associated with smolting at 2 years of age. Sexually mature male parr from the high ration, high lipid content treatment were also subjected to saltwater challenge tests, and were found to be unable to regulate plasma sodium levels. The proportion of sexually mature male parr was reduced when the fish were fed low feed rations, but was not affected by the lipid content of the feed. Salmo salar fed low rations with low lipid content exhibited the highest degree of severe fin erosion. © 2014 The Fisheries Society of the British Isles.

Separation of phospholipids in microfluidic chip device: application to high-throughput screening assays for lipid-modifying enzymes.

PubMed

Lin, Sansan; Fischl, Anthony S; Bi, Xiahui; Parce, Wally

2003-03-01

Phospholipid molecules such as ceramide and phosphoinositides play crucial roles in signal transduction pathways. Lipid-modifying enzymes including sphingomyelinase and phosphoinositide kinases regulate the generation and degradation of these lipid-signaling molecules and are important therapeutic targets in drug discovery. We now report a sensitive and convenient method to separate these lipids using microfluidic chip-based technology. The method takes advantage of the high-separation power of the microchips that separate lipids based on micellar electrokinetic capillary chromatography (MEKC) and the high sensitivity of fluorescence detection. We further exploited the method to develop a homogenous assay to monitor activities of lipid-modifying enzymes. The assay format consists of two steps: an on-plate enzymatic reaction using fluorescently labeled substrates followed by an on-chip MEKC separation of the reaction products from the substrates. The utility of the assay format for high-throughput screening (HTS) is demonstrated using phospholipase A(2) on the Caliper 250 HTS system: throughput of 80min per 384-well plate can be achieved with unattended running time of 5.4h. This enabling technology for assaying lipid-modifying enzymes is ideal for HTS because it avoids the use of radioactive substrates and complicated separation/washing steps and detects both substrate and product simultaneously.

Fine-mapping of lipid regions in global populations discovers ethnic-specific signals and refines previously identified lipid loci.

PubMed

Zubair, Niha; Graff, Mariaelisa; Luis Ambite, Jose; Bush, William S; Kichaev, Gleb; Lu, Yingchang; Manichaikul, Ani; Sheu, Wayne H-H; Absher, Devin; Assimes, Themistocles L; Bielinski, Suzette J; Bottinger, Erwin P; Buzkova, Petra; Chuang, Lee-Ming; Chung, Ren-Hua; Cochran, Barbara; Dumitrescu, Logan; Gottesman, Omri; Haessler, Jeffrey W; Haiman, Christopher; Heiss, Gerardo; Hsiung, Chao A; Hung, Yi-Jen; Hwu, Chii-Min; Juang, Jyh-Ming J; Le Marchand, Loic; Lee, I-Te; Lee, Wen-Jane; Lin, Li-An; Lin, Danyu; Lin, Shih-Yi; Mackey, Rachel H; Martin, Lisa W; Pasaniuc, Bogdan; Peters, Ulrike; Predazzi, Irene; Quertermous, Thomas; Reiner, Alex P; Robinson, Jennifer; Rotter, Jerome I; Ryckman, Kelli K; Schreiner, Pamela J; Stahl, Eli; Tao, Ran; Tsai, Michael Y; Waite, Lindsay L; Wang, Tzung-Dau; Buyske, Steven; Ida Chen, Yii-Der; Cheng, Iona; Crawford, Dana C; Loos, Ruth J F; Rich, Stephen S; Fornage, Myriam; North, Kari E; Kooperberg, Charles; Carty, Cara L

2016-12-15

Genome-wide association studies have identified over 150 loci associated with lipid traits, however, no large-scale studies exist for Hispanics and other minority populations. Additionally, the genetic architecture of lipid-influencing loci remains largely unknown. We performed one of the most racially/ethnically diverse fine-mapping genetic studies of HDL-C, LDL-C, and triglycerides to-date using SNPs on the MetaboChip array on 54,119 individuals: 21,304 African Americans, 19,829 Hispanic Americans, 12,456 Asians, and 530 American Indians. The majority of signals found in these groups generalize to European Americans. While we uncovered signals unique to racial/ethnic populations, we also observed systematically consistent lipid associations across these groups. In African Americans, we identified three novel signals associated with HDL-C (LPL, APOA5, LCAT) and two associated with LDL-C (ABCG8, DHODH). In addition, using this population, we refined the location for 16 out of the 58 known MetaboChip lipid loci. These results can guide tailored screening efforts, reveal population-specific responses to lipid-lowering medications, and aid in the development of new targeted drug therapies. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Core-based lipid nanoparticles as a nanoplatform for delivery of near-infrared fluorescent imaging agents.

PubMed

Anikeeva, Nadia; Sykulev, Yuri; Delikatny, Edward J; Popov, Anatoliy V

2014-01-01

Pyropheophorbide a (Pyro) is a near-infrared (NIR) fluorescent dye and photosensitizer with high quantum yield that makes the dye suitable for tumor treatment both as an imaging and therapy agent. We have designed and synthesized a series of a Pyro-based NIR probes, based on the conjugation of Pyro with lipids. The nature of our probes requires the use of a lipophilic carrier to deliver the probes to cancer cell membranes. To address this, we have utilized lipid-based nanoparticles (LNPs) consisting of PEGylated lipids, which form the nanoparticle shell, and a lipid core. To endow the LNPs with targeting properties, nitrilotriacetic acid (NTA) lipids were included in the composition that enables the non-covalent attachment of His-tag targeting proteins preserving their functional activity. We found that the nature of the core molecules influence the nanoparticle size, shelf-life and stability at physiological temperature. Two different Pyro-lipid conjugates were loaded either into the core or shell of the LNPs. The conjugates revealed differential ability to be accumulated in the cell membrane of the target cells with time. Thus, the modular organization of the core-shell LNPs allows facile adjustment of their composition with goal to fine tuning the nanoparticle properties for in vivo application.

Core-based lipid nanoparticles as a nanoplatform for delivery of near-infrared fluorescent imaging agents

PubMed Central

Anikeeva, Nadia; Sykulev, Yuri; Delikatny, Edward J; Popov, Anatoliy V

2014-01-01

Pyropheophorbide a (Pyro) is a near-infrared (NIR) fluorescent dye and photosensitizer with high quantum yield that makes the dye suitable for tumor treatment both as an imaging and therapy agent. We have designed and synthesized a series of a Pyro-based NIR probes, based on the conjugation of Pyro with lipids. The nature of our probes requires the use of a lipophilic carrier to deliver the probes to cancer cell membranes. To address this, we have utilized lipid-based nanoparticles (LNPs) consisting of PEGylated lipids, which form the nanoparticle shell, and a lipid core. To endow the LNPs with targeting properties, nitrilotriacetic acid (NTA) lipids were included in the composition that enables the non-covalent attachment of His-tag targeting proteins preserving their functional activity. We found that the nature of the core molecules influence the nanoparticle size, shelf-life and stability at physiological temperature. Two different Pyro-lipid conjugates were loaded either into the core or shell of the LNPs. The conjugates revealed differential ability to be accumulated in the cell membrane of the target cells with time. Thus, the modular organization of the core-shell LNPs allows facile adjustment of their composition with goal to fine tuning the nanoparticle properties for in vivo application. PMID:25250201

Impedance dispersion analysis of drug-membrane interactions

NASA Astrophysics Data System (ADS)

Tacheva, Bilyana; Paarvanova, Boyana; Ivanov, Ivan T.; Karabaliev, Miroslav

2017-11-01

Thin lipid films modified glassy carbon electrodes (GCE) were used in this work as model system for studying the interactions between two antipsychotic phenothiazine drugs, chlorpromazine and thioridazine, and the lipid fraction of the biomembranes. The lipid films on the electrode surface were obtained through the thinning of film-forming lipid solution deposited between an electrolyte phase and the working GC electrode. The effects of the drugs on the lipid film structure were investigated by electrochemical impedance spectroscopy (EIS). To characterize the electric properties of the lipid film the impedance of the working GCE is modeled with an equivalent circuit consisting of parallel capacitance Cp and resistance Rp. These capacitance and resistance are not frequency independent but could be calculated as equivalent Cp and Rp for each measured frequency of the impedance spectrum and presented as functions of the frequency f, Cp = Cp(f) and Rp= Rp(f). For the lipid films used in this work, it is demonstrated that both Cp(f) and Rp(f) are well approximated with power-law functions. This behavior implies that the impedance Z of the films could be analysed in terms of the well-known constant-phase angle element (CPE), which is often used to describe the interfacial impedance of solid working electrodes.

MALDI Mass Spectrometry Imaging of Lipids and Gene Expression Reveals Differences in Fatty Acid Metabolism between Follicular Compartments in Porcine Ovaries

PubMed Central

Uzbekova, Svetlana; Elis, Sebastien; Teixeira-Gomes, Ana-Paula; Desmarchais, Alice; Maillard, Virginie; Labas, Valerie

2015-01-01

In mammals, oocytes develop inside the ovarian follicles; this process is strongly supported by the surrounding follicular environment consisting of cumulus, granulosa and theca cells, and follicular fluid. In the antral follicle, the final stages of oogenesis require large amounts of energy that is produced by follicular cells from substrates including glucose, amino acids and fatty acids (FAs). Since lipid metabolism plays an important role in acquiring oocyte developmental competence, the aim of this study was to investigate site-specificity of lipid metabolism in ovaries by comparing lipid profiles and expression of FA metabolism-related genes in different ovarian compartments. Using MALDI Mass Spectrometry Imaging, images of porcine ovary sections were reconstructed from lipid ion signals for the first time. Cluster analysis of ion spectra revealed differences in spatial distribution of lipid species among ovarian compartments, notably between the follicles and interstitial tissue. Inside the follicles analysis differentiated follicular fluid, granulosa, theca and the oocyte-cumulus complex. Moreover, by transcript quantification using real time PCR, we showed that expression of five key genes in FA metabolism significantly varied between somatic follicular cells (theca, granulosa and cumulus) and the oocyte. In conclusion, lipid metabolism differs between ovarian and follicular compartments. PMID:25756245

Francisella guangzhouensis sp. nov., isolated from air-conditioning systems.

PubMed

Qu, Ping-Hua; Chen, Shou-Yi; Scholz, Holger C; Busse, Hans-Jürgen; Gu, Quan; Kämpfer, Peter; Foster, Jeffrey T; Glaeser, Stefanie P; Chen, Cha; Yang, Zhi-Chong

2013-10-01

Four strains (08HL01032(T), 09HG994, 10HP82-6 and 10HL1960) were isolated from water of air-conditioning systems of various cooling towers in Guangzhou city, China. Cells were Gram-stain-negative coccobacilli without flagella, catalase-positive and oxidase-negative, showing no reduction of nitrate, no hydrolysis of urea and no production of H2S. Growth was characteristically enhanced in the presence of l-cysteine, which was consistent with the properties of members of the genus Francisella. The quinone system was composed of ubiquinone Q-8 with minor amounts of Q-9. The polar lipid profile consisted of the predominant lipids phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, two unidentified phospholipids (PL2, PL3), an unidentified aminophospholipid and an unidentified glycolipid (GL2). The polyamine pattern consisted of the major compounds spermidine, cadaverine and spermine. The major cellular fatty acids were C10 : 0, C14 : 0, C16 : 0, C18 : 1ω9c and C18 : 1 3-OH. A draft whole-genome sequence of the proposed type strain 08HL01032(T) was generated. Comparative sequence analysis of the complete 16S and 23S rRNA genes confirmed affiliation to the genus Francisella, with 95 % sequence identity to the closest relatives in the database, the type strains of Francisella philomiragia and Francisella noatunensis subsp. orientalis. Full-length deduced amino acid sequences of various housekeeping genes, recA, gyrB, groEL, dnaK, rpoA, rpoB, rpoD, rpoH, fopA and sdhA, exhibited similarities of 67-92 % to strains of other species of the genus Francisella. Strains 08HL01032(T), 09HG994, 10HP82-6 and 10HL1960 exhibited highly similar pan-genome PCR profiles. Both the phenotypic and molecular data support the conclusion that the four strains belong to the genus Francisella but exhibit considerable divergence from all recognized Francisella species. Therefore, we propose the name Francisella guangzhouensis sp. nov., with the type strain 08HL01032(T) ( = CCUG 60119(T) = NCTC 13503(T)).

Characterization of human DHRS6, an orphan short chain dehydrogenase/reductase enzyme: a novel, cytosolic type 2 R-beta-hydroxybutyrate dehydrogenase.

PubMed

Guo, Kunde; Lukacik, Petra; Papagrigoriou, Evangelos; Meier, Marc; Lee, Wen Hwa; Adamski, Jerzy; Oppermann, Udo

2006-04-14

Human DHRS6 is a previously uncharacterized member of the short chain dehydrogenases/reductase family and displays significant homologies to bacterial hydroxybutyrate dehydrogenases. Substrate screening reveals sole NAD(+)-dependent conversion of (R)-hydroxybutyrate to acetoacetate with K(m) values of about 10 mm, consistent with plasma levels of circulating ketone bodies in situations of starvation or ketoacidosis. The structure of human DHRS6 was determined at a resolution of 1.8 A in complex with NAD(H) and reveals a tetrameric organization with a short chain dehydrogenases/reductase-typical folding pattern. A highly conserved triad of Arg residues ("triple R" motif consisting of Arg(144), Arg(188), and Arg(205)) was found to bind a sulfate molecule at the active site. Docking analysis of R-beta-hydroxybutyrate into the active site reveals an experimentally consistent model of substrate carboxylate binding and catalytically competent orientation. GFP reporter gene analysis reveals a cytosolic localization upon transfection into mammalian cells. These data establish DHRS6 as a novel, cytosolic type 2 (R)-hydroxybutyrate dehydrogenase, distinct from its well characterized mitochondrial type 1 counterpart. The properties determined for DHRS6 suggest a possible physiological role in cytosolic ketone body utilization, either as a secondary system for energy supply in starvation or to generate precursors for lipid and sterol synthesis.

Identification of Shared and Unique Serum Lipid Profiles in Diabetes Mellitus and Myocardial Infarction.

PubMed

Kjellqvist, Sanela; Klose, Christian; Surma, Michal A; Hindy, George; Mollet, Inês G; Johansson, Anna; Chavaux, Patrick; Gottfries, Johan; Simons, Kai; Melander, Olle; Fernandez, Céline

2016-11-29

Diabetes mellitus (DM) and cardiovascular disease are associated with dyslipidemia, but the detailed lipid molecular pattern in both diseases remains unknown. We used shotgun mass spectrometry to determine serum levels of 255 molecular lipids in 316 controls, 171 DM, and 99 myocardial infarction (MI) events from a cohort derived from the Malmö Diet and Cancer study. Orthogonal projections to latent structures analyses were conducted between the lipids and clinical parameters describing DM or MI. Fatty acid desaturases (FADS) and elongation of very long chain fatty acid protein 5 (ELOVL5) activities were estimated by calculating product to precursor ratios of polyunsaturated fatty acids in complex lipids. FADS genotypes encoding these desaturases were then tested for association with lipid levels and ratios. Differences in the levels of lipids belonging to the phosphatidylcholine and triacylglyceride (TAG) classes contributed the most to separating DM from controls. TAGs also played a dominating role in discriminating MI from controls. Levels of C18:2 fatty acids in complex lipids were lower both in DM and MI versus controls (DM, P=0.004; MI, P=6.0E-06) at least due to an acceleration in the metabolic flux from C18:2 to C20:4 (eg, increased estimated ELOVL5: DM, P=0.02; MI, P=0.04, and combined elongase-desaturase activities: DM, P=3.0E-06; MI, P=2.0E-06). Minor allele carriers of FADS genotypes were associated with increased levels of C18:2 (P≤0.007) and lower desaturase activity (P≤0.002). We demonstrate a possible relationship between decreased levels of C18:2 in complex lipids and DM or MI. We thereby highlight the importance of molecular lipids in the pathogenesis of both diseases. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Hydrophobic mismatch sorts SNARE proteins into distinct membrane domains

PubMed Central

Milovanovic, Dragomir; Honigmann, Alf; Koike, Seiichi; Göttfert, Fabian; Pähler, Gesa; Junius, Meike; Müllar, Stefan; Diederichsen, Ulf; Janshoff, Andreas; Grubmüller, Helmut; Risselada, Herre J.; Eggeling, Christian; Hell, Stefan W.; van den Bogaart, Geert; Jahn, Reinhard

2015-01-01

The clustering of proteins and lipids in distinct microdomains is emerging as an important principle for the spatial patterning of biological membranes. Such domain formation can be the result of hydrophobic and ionic interactions with membrane lipids as well as of specific protein–protein interactions. Here using plasma membrane-resident SNARE proteins as model, we show that hydrophobic mismatch between the length of transmembrane domains (TMDs) and the thickness of the lipid membrane suffices to induce clustering of proteins. Even when the TMDs differ in length by only a single residue, hydrophobic mismatch can segregate structurally closely homologous membrane proteins in distinct membrane domains. Domain formation is further fine-tuned by interactions with polyanionic phosphoinositides and homo and heterotypic protein interactions. Our findings demonstrate that hydrophobic mismatch contributes to the structural organization of membranes. PMID:25635869

Elucidation of Lipid Binding Sites on Lung Surfactant Protein A Using X-ray Crystallography, Mutagenesis, and Molecular Dynamics Simulations.

PubMed

Goh, Boon Chong; Wu, Huixing; Rynkiewicz, Michael J; Schulten, Klaus; Seaton, Barbara A; McCormack, Francis X

2016-07-05

Surfactant protein A (SP-A) is a collagenous C-type lectin (collectin) that is critical for pulmonary defense against inhaled microorganisms. Bifunctional avidity of SP-A for pathogen-associated molecular patterns (PAMPs) such as lipid A and for dipalmitoylphosphatidylcholine (DPPC), the major component of surfactant membranes lining the air-liquid interface of the lung, ensures that the protein is poised for first-line interactions with inhaled pathogens. To improve our understanding of the motifs that are required for interactions with microbes and surfactant structures, we explored the role of the tyrosine-rich binding surface on the carbohydrate recognition domain of SP-A in the interaction with DPPC and lipid A using crystallography, site-directed mutagenesis, and molecular dynamics simulations. Critical binding features for DPPC binding include a three-walled tyrosine cage that binds the choline headgroup through cation-π interactions and a positively charged cluster that binds the phosphoryl group. This basic cluster is also critical for binding of lipid A, a bacterial PAMP and target for SP-A. Molecular dynamics simulations further predict that SP-A binds lipid A more tightly than DPPC. These results suggest that the differential binding properties of SP-A favor transfer of the protein from surfactant DPPC to pathogen membranes containing appropriate lipid PAMPs to effect key host defense functions.

The novel oleaginous bacterium Sphingomonas sp. EGY1 DSM 29616: a value added platform for renewable biodiesel.

PubMed

Amer, Nehad N; Elbahloul, Yasser; Embaby, Amira M; Hussein, Ahmed

2017-07-01

Oleaginous microorganisms are regarded as efficient, renewable cell factories for lipid biosynthesis, a biodiesel precursor, to overwhelm the cosmopolitan energy crisis with affordable investment capital costs. Present research highlights production and characterization of lipids by a newly isolated oleaginous bacterium, Sphingomonas sp. EGY1 DSM 29616 through an eco-friendly approach. Only sweet whey [42.1% (v/v)] in tap water was efficiently used as a growth medium and lipid production medium to encourage cell growth and trigger lipid accumulation simultaneously. Cultivation of Sphingomonas sp. EGY1 DSM 29616 in shake flasks resulted in the accumulation of 8.5 g L -1 lipids inside the cells after 36 h at 30 °C. Triglycerides of C16:C18 saturated and unsaturated fatty acids showed a similar pattern to tripalmitin or triolein; deduced from gas chromatography (GC), thin layer chromatography (TLC), and Matrix-assisted laser desorption/ionization time-of-flight-mass spectra analysis (MALDI-TOF-MS) analyses. Batch cultivation 2.5 L in a laboratory scale fermenter led to 13.8 g L -1 accumulated lipids after 34 h at 30 °C. Present data would underpin the potential of Sphingomonas sp. EGY1 DSM 29616 as a novel renewable cell factory for biosynthesis of biodiesel.

Optimised purification and characterisation of lipid transfer protein 1 (LTP1) and its lipid-bound isoform LTP1b from barley malt.

PubMed

Nieuwoudt, Melanie; Lombard, Nicolaas; Rautenbach, Marina

2014-08-15

In beer brewing, brewers worldwide strive to obtain product consistency in terms of flavour, colour and foam. Important proteins contributing to beer foam are lipid transfer proteins (LTPs), in particular LTP1 and its lipid-bound isoform LTP1b, which are known to transport lipids in vivo and prevent lipids from destabilising the beer foam. LTP1 and LTP1b were successfully purified using only five purification steps with a high purified protein yield (160 mg LTP1 and LTP1b from 200 g barley). Circular dichroism of LTP1 and LTP1b confirmed that both proteins are highly tolerant to high temperatures (>90 °C) and are pH stable, particularly at a neutral to a more basic pH. Only LTP1 exhibited antiyeast and thermo-stable lytic activity, while LTP1b was inactive, indicating that the fatty acid moiety compromised the antimicrobial activity of LTP1. This lack in antiyeast activity and the positive foam properties of LTP1b would benefit beer fermentation and quality. Copyright © 2014 Elsevier Ltd. All rights reserved.

Structure and organization of nanosized-inclusion-containing bilayer membranes

NASA Astrophysics Data System (ADS)

Ren, Chun-Lai; Ma, Yu-Qiang

2009-07-01

Based on a considerable amount of experimental evidence for lateral organization of lipid membranes which share astonishingly similar features in the presence of different inclusions, we use a hybrid self-consistent field theory (SCFT)/density-functional theory (DFT) approach to deal with bilayer membranes embedded by nanosized inclusions and explain experimental findings. Here, the hydrophobic inclusions are simple models of hydrophobic drugs or other nanoparticles for biomedical applications. It is found that lipid/inclusion-rich domains are formed at moderate inclusion concentrations and disappear with the increase in the concentration of inclusions. At high inclusion content, chaining of inclusions occurs due to the effective depletion attraction between inclusions mediated by lipids. Meanwhile, the increase in the concentration of inclusions can also cause thickening of the membrane and the distribution of inclusions undergoes a layering transition from one-layer structure located in the bilayer midplane to two-layer structure arranged into the two leaflets of a bilayer. Our theoretical predictions address the complex interactions between membranes and inclusions suggesting a unifying mechanism which reflects the competition between the conformational entropy of lipids favoring the formation of lipid- and inclusion-rich domains in lipids and the steric repulsion of inclusions leading to the uniform dispersion.

2-Nonenal newly found in human body odor tends to increase with aging.

PubMed

Haze, S; Gozu, Y; Nakamura, S; Kohno, Y; Sawano, K; Ohta, H; Yamazaki, K

2001-04-01

Human body odor consists of various kinds of odor components. Here, we have investigated the changes in body odor associated with aging. The body odor of subjects between the ages of 26 and 75 was analyzed by headspace gas chromatography/mass spectrometry. 2-Nonenal, an unsaturated aldehyde with an unpleasant greasy and grassy odor, was detected only in older subjects (40 y or older). Furthermore, analysis of skin surface lipids revealed that omega7 unsaturated fatty acids and lipid peroxides also increased with aging and that there were positive correlations between the amount of 2-nonenal in body odor and the amount of omega7 unsaturated fatty acids or lipid peroxides in skin surface lipids. 2-Nonenal was generated only when omega7 unsaturated fatty acids were degraded by degradation tests in which some main components of skin surface lipids were oxidatively decomposed using lipid peroxides as initiator of an oxidative chain reaction. The results indicate that 2-nonenal is generated by the oxidative degradation of omega7 unsaturated fatty acids, and suggest that 2-nonenal may be involved in the age-related change of body odor.

Lipid composition dictates serum stability of reconstituted high-density lipoproteins: implications for in vivo applications.

PubMed

Gilmore, Sean F; Carpenter, Timothy S; Ingólfsson, Helgi I; Peters, Sandra K G; Henderson, Paul T; Blanchette, Craig D; Fischer, Nicholas O

2018-04-26

Nanolipoprotein particles (NLPs) are reconstituted high-density lipoproteins, consisting of a phospholipid bilayer stabilized by an apolipoprotein scaffold protein. This class of nanoparticle has been a vital tool in the study of membrane proteins, and in recent years has been increasingly used for in vivo applications. Previous work demonstrated that the composition of the lipid bilayer component affects the stability of these particles in serum solutions. In the current study, NLPs assembled with phosphatidylcholine lipids featuring different acyl chain structures were systematically tested to understand the effect that lipid composition has on NLP stability in both neat serum and cell culture media supplemented with 10% serum by volume. The time at which 50% of the particles dissociate, as well as the fraction of the initial population that remains resistant to dissociation, were correlated to key parameters obtained from all-atom simulations of the corresponding lipid bilayers. A significant correlation was observed between the compressibility modulus of the lipid bilayer and particle stability in these complex biological milieu. These results can be used as a reference to tune the stability of these versatile biological nanoparticles for in vitro and in vivo applications.

Glomerular Lesions in Proteinuric Miniature Schnauzer Dogs

PubMed Central

Furrow, E.; Lees, G. E.; Brown, C. A.; Cianciolo, R. E.

2017-01-01

Miniature Schnauzer dogs are predisposed to idiopathic hypertriglyerceridemia, which increases risk for diseases such as pancreatitis and gallbladder mucocele. Recently, elevated triglyceride concentrations have been associated with proteinuria in this breed, although it is difficult to determine which abnormality is primary. Retrospective review of renal tissue from 27 proteinuric Miniature Schnauzers revealed that 20 dogs had ultrastructural evidence of osmophilic globules consistent with lipid in glomerular tufts. Seven of these dogs had lipid thromboemboli in glomerular capillary loops that distorted their shape and compressed circulating erythrocytes. Triglyceride concentrations were reported in 6 of these 7 dogs, and all were hypertriglyceridemic. In addition, glomerular lipidosis (defined as accumulation of foam cells within peripheral capillary loops) was identified in a single dog. The remaining 12 dogs had smaller amounts of lipid that could only be identified ultrastructurally. Neither signalment data nor clinicopathologic parameters (serum albumin, serum creatinine, urine protein-to-creatinine ratio, and blood pressure) differed among the various types of lipid lesions. During the time course of this study, all dogs diagnosed with glomerular lipid thromboemboli were Miniature Schnauzers, underscoring the importance of recognizing these clear spaces within capillary loops as lipid. PMID:28005494

Endrin-induced histopathological changes and lipid peroxidation in livers and kidneys of rats, mice, guinea pigs and hamsters.

PubMed

Hassan, M Q; Numan, I T; al-Nasiri, N; Stohs, S J

1991-01-01

Endrin toxicity may be due to an oxidative stress associated with increased lipid peroxidation, decreased glutathione content, and inhibition of glutathione peroxidase activity. Extensive interspecies variability exists in sensitivity towards endrin. Therefore, histopathological changes and lipid peroxidation in the livers and kidneys of rats, mice, hamsters, and guinea pigs were examined 24 hr after the administration of 4 mg endrin/kg body weight orally in corn oil. Degeneration and necrotic changes with inflammatory cell infiltration were observed in livers and kidneys, and interspecies variability occurred. Fatty changes in the form of hepatic foam cells with cytoplasmic vacuolation were present. Lipofuscin pigments, associated with lipid peroxidation, were observed in hepatocytes and Kupffer cells. These histopathological conditions were prevented in rats which had been pretreated with butylated hydroxyanisole, vitamins E and C, or cysteine, antioxidants and free radical scavengers which have previously been shown to inhibit lipid peroxidation. The extent of endrin-induced lipid peroxidation correlated well with the degree of histopathological changes. Thus, histological changes consistent with the induction of an oxidative stress were observed following the administration of endrin to various animal species.

Cellular Lipids of a Nocardia Grown on Propane and n-Butane

PubMed Central

Davis, J. B.

1964-01-01

Lipid fractions of propane- and n-butane-grown nocardial cells each contain a chloroform-soluble, ether-insoluble polymer not observed previously in liquid n-alkane-grown cells. The polymer in propane-grown cells is poly-β-hydroxybutyrate. The polymer in n-butane-grown cells apparently contains unsaturation in the molecule, and is identified tentatively as a co-polymer of β-hydroxybutyric and β-hydroxybutenoic (specifically 3-hydroxy 2-butenoic) acids. The other major component of the lipid fraction consists of triglycerides containing principally palmitic and stearic acids. There seems to be little qualitative distinction in the glycerides of propane- or n-butane-grown cells. Oxidative assimilation of n-butane is described. PMID:14199017

Optical stretching as a tool to investigate the mechanical properties of lipid bilayers.

PubMed

Solmaz, Mehmet E; Sankhagowit, Shalene; Biswas, Roshni; Mejia, Camilo A; Povinelli, Michelle L; Malmstadt, Noah

2013-10-07

Measurements of lipid bilayer bending modulus by various techniques produce widely divergent results. We attempt to resolve some of this ambiguity by measuring bending modulus in a system that can rapidly process large numbers of samples, yielding population statistics. This system is based on optical stretching of giant unilamellar vesicles (GUVs) in a microfluidic dual-beam optical trap (DBOT). The microfluidic DBOT system is used here to measure three populations of GUVs with distinct lipid compositions. We find that gel-phase membranes are significantly stiffer than liquid-phase membranes, consistent with previous reports. We also find that the addition of cholesterol does not alter the bending modulus of membranes composed of a monounsaturated phospholipid.

Lipid peroxidative damage in the erythrocytes and elevation of serum LDL-cholesterol, apolipoprotein-B, ferritin and uric acid with age and in coronary heart disease patients.

PubMed

El-Gebali, H H; Tahir, S A; Haider, S S; El-Fakhri, M M

2000-02-01

To determine the normal serum levels of LDL-cholesterol, apolipoprotein-B, ferritin, uric acid, and the extent of erythrocytes lipid peroxidation in healthy control group subjects and to compare them with coronary heart disease patients. Secondly, to study the effects of age and sex on these parameters. The blood samples from 150 healthy Libyan control group subjects (110 men and 40 women) were classified into 3 groups according to their age. Group I consisted of 76 subjects with an age range from 20 to 35 years. Group II consisted of 45 subjects with an age range from 36 to 50 years. Group III consisted of 29 subjects with an age range from 51 to 74 years. The blood samples from these groups were analyzed for LDL-cholesterol, apolipoprotein-B, ferritin and uric acid levels. Lipid peroxidation was compared in the erythrocytes of 56 selected healthy control group subjects (31 men and 11 women) of the aforementioned age groups. These parameters have shown age-dependent elevation in their levels. Meanwhile, LDL-cholesterol and Apolipoprotein-B levels in female subjects were higher than those of males. However, lipid peroxidation in the erythrocytes has revealed a statistically significant increase with increasing age. The comparison between 93 selected, sex and age matched, healthy control group subjects with 87 selected coronary heart disease patients (55 men and 45 women) with an age range from 30 to 74 years (49.6+13.25) has demonstrated significantly higher concentration of LDL-cholesterol, Apolipoprotein-B, ferritin and uric acid in coronary heart disease patients than those of healthy control group subjects. Meanwhile, lipid peroxidation was also significantly enhanced in coronary heart disease patients compared with healthy control group subjects. Our study has revealed that an increase in the lipid peroxidation in erythrocytes with age and during coronary heart disease, makes red cell membranes more vulnerable to free radical damage via formation of reactive oxygen species. It is thus likely that peroxidative damage may be contributing to an increase in serum LDL-cholesterol, Apolipoprotein-B, probably after its oxidative modification, increase in ferritin and hyperuricemia in coronary heart disease patients.

Characterization of Lipid A Variants by Energy-Resolved Mass Spectrometry: Impact of Acyl Chains

NASA Astrophysics Data System (ADS)

Crittenden, Christopher M.; Akin, Lucas D.; Morrison, Lindsay J.; Trent, M. Stephen; Brodbelt, Jennifer S.

2017-06-01

Lipid A molecules consist of a diglucosamine sugar core with a number of appended acyl chains that vary in their length and connectivity. Because of the challenging nature of characterizing these molecules and differentiating between isomeric species, an energy-resolved MS/MS strategy was undertaken to track the fragmentation trends and map genealogies of product ions originating from consecutive cleavages of acyl chains. Generalizations were developed based on the number and locations of the primary and secondary acyl chains as well as variations in preferential cleavages arising from the location of the phosphate groups. Secondary acyl chain cleavage occurs most readily for lipid A species at the 3' position, followed by primary acyl chain fragmentation at both the 3' and 3 positions. In the instances of bisphosphorylated lipid A variants, phosphate loss occurs readily in conjunction with the most favorable primary and secondary acyl chain cleavages. [Figure not available: see fulltext.

Nanostructured nanoparticles of self-assembled lipid pro-drugs as a route to improved chemotherapeutic agents.

PubMed

Sagnella, Sharon M; Gong, Xiaojuan; Moghaddam, Minoo J; Conn, Charlotte E; Kimpton, Kathleen; Waddington, Lynne J; Krodkiewska, Irena; Drummond, Calum J

2011-03-01

We demonstrate that oral delivery of self-assembled nanostructured nanoparticles consisting of 5-fluorouracil (5-FU) lipid prodrugs results in a highly effective, target-activated, chemotherapeutic agent, and offers significantly enhanced efficacy over a commercially available alternative that does not self-assemble. The lipid prodrug nanoparticles have been found to significantly slow the growth of a highly aggressive mouse 4T1 breast tumour, and essentially halt the growth of a human MDA-MB-231 breast tumour in mouse xenografts. Systemic toxicity is avoided as prodrug activation requires a three-step, enzymatic conversion to 5-FU, with the third step occurring preferentially at the tumour site. Additionally, differences in the lipid prodrug chemical structure and internal nanostructure of the nanoparticle dictate the enzymatic conversion rate and can be used to control sustained release profiles. Thus, we have developed novel oral nanomedicines that combine sustained release properties with target-selective activation.

Polar Lipids Analysis of Cultured Phytoplankton Reveals Significant Inter-taxa Changes, Low Influence of Growth Stage, and Usefulness in Chemotaxonomy.

PubMed

Cañavate, José Pedro; Armada, Isabel; Hachero-Cruzado, Ismael

2017-05-01

The high lipid diversity of microalgae has been used to taxonomically differentiate phytoplankton taxa at the class level. However, important lipids such as phospholipids (PL) and betaine lipids (BL) with potential chemotaxonomy application in phytoplankton ecology have been scarcely studied. The chemotaxonomy value of PL and BL depends on their intraspecific extent of variation as microalgae respond to external changing factors. To determine such effects, lipid class changes occurring at different growth stages in 15 microalgae from ten different classes were analyzed. BL occurred in 14 species and were the less affected lipids by growth stage with diacylglyceryl-hydroxymethyl-N,N,N-trimethyl-b-alanine (DGTA) showing the highest stability. PL were more influenced by growth stage with phosphatidylcholine (PC), phosphatidylglycerol (PG), and phosphatidyletanolamine (PE) declining towards older culture stages in some species. Glycolipids were the more common lipids, and no evident age-related variability pattern could be associated to taxonomic diversity. Selecting BL and PL as descriptor variables optimally distinguished microalgae taxonomic variability at all growth stages. Principal coordinate analysis arranged species through a main tendency from diacylglyceryl-hydroxymethyl-N,N,N-trimethyl-b-alanine (DGCC) containing species (mainly dinoflagellates and haptophytes) to DGTA or PC containing species (mainly cryptophytes). Two diatom classes with similar fatty acid profiles could be distinguished from their respective content in DGTA (Bacillariophyceae) or DGCC (Mediophyceae). In green lineage classes (Trebouxiophyceae, Porphyridophyceae, and Chlorodendrophyceae), PC was a better descriptor than BL. BL and PL explained a higher proportion of microalgae taxonomic variation than did fatty acids and played a complementary role as lipid markers.

Mono- and Dialkyl Glycerol Ether Lipids in Anaerobic Bacteria: Biosynthetic Insights from the Mesophilic Sulfate Reducer Desulfatibacillum alkenivorans PF2803T

PubMed Central

Mollex, Damien; Vinçon-Laugier, Arnauld; Hakil, Florence; Pacton, Muriel; Cravo-Laureau, Cristiana

2015-01-01

Bacterial glycerol ether lipids (alkylglycerols) have received increasing attention during the last decades, notably due to their potential role in cell resistance or adaptation to adverse environmental conditions. Major uncertainties remain, however, regarding the origin, biosynthesis, and modes of formation of these uncommon bacterial lipids. We report here the preponderance of monoalkyl- and dialkylglycerols (1-O-alkyl-, 2-O-alkyl-, and 1,2-O-dialkylglycerols) among the hydrolyzed lipids of the marine mesophilic sulfate-reducing proteobacterium Desulfatibacillum alkenivorans PF2803T grown on n-alkenes (pentadec-1-ene or hexadec-1-ene) as the sole carbon and energy source. Alkylglycerols account for one-third to two-thirds of the total cellular lipids (alkylglycerols plus acylglycerols), depending on the growth substrate, with dialkylglycerols contributing to one-fifth to two-fifths of the total ether lipids. The carbon chain distribution of the lipids of D. alkenivorans also depends on that of the substrate, but the chain length and methyl-branching patterns of fatty acids and monoalkyl- and dialkylglycerols are systematically congruent, supporting the idea of a biosynthetic link between the three classes of compounds. Vinyl ethers (1-alken-1′-yl-glycerols, known as plasmalogens) are not detected among the lipids of strain PF2803T. Cultures grown on different (per)deuterated n-alkene, n-alkanol, and n-fatty acid substrates further demonstrate that saturated alkylglycerols are not formed via the reduction of hypothetic alken-1′-yl intermediates. Our results support an unprecedented biosynthetic pathway to monoalkyl/monoacyl- and dialkylglycerols in anaerobic bacteria and suggest that n-alkyl compounds present in the environment can serve as the substrates for supplying the building blocks of ether phospholipids of heterotrophic bacteria. PMID:25724965

Sulfation pattern of fucose branches affects the anti-hyperlipidemic activities of fucosylated chondroitin sulfate.

PubMed

Wu, Nian; Zhang, Yu; Ye, Xingqian; Hu, Yaqin; Ding, Tian; Chen, Shiguo

2016-08-20

Fucosylated chondroitin sulfates (fCSs) are glycosaminoglycans extracted from sea cucumbers, consisting of chondroitin sulfate E (CSE) backbones and sulfated fucose branches. The biological properties of fCSs could be affected by the sulfation pattern of their fucose branches. In the present study, two fCSs were isolated from sea cucumbers Isostichopus badionotus (fCS-Ib) and Pearsonothuria graeffei (fCS-Pg). Their monosaccharide compositions of glucuronic acid (GlcA), N-acetylgalactosamine (GalNAc), fucose (Fuc) and sulfate were at similar molar ratio with 1.0/0.7/0.9/3.1 for fCS-Ib and 1.0/0.8/1.5/2.6 for fCS-Pg. The two fCSs have different sulfation patterns on their fucose branches, fCS-Pg with 3,4-O-disulfation while fCS-Ib with 2,4-O-disulfation. Their antihyperlipidemic effects were compared using a high-fat high-fructose diet (HFFD)-fed C57BL/6J mice model. Both fCS-Ib and fCS-Pg had significant effects on lipid profile improvement, liver protection, blood glucose diminution and hepatic glycogen synthesis. Specifically, fCS-Pg with 3,4-O-disulfation fucose branches was more effective in reduction of blood cholesterol (TC), low density lipoprotein (LDL) and atherogenic index (AI). Our results indicate that both fCSs, especially fCS-Pg, could be used as a potential anti-hyperlipidemic drug. Copyright © 2016. Published by Elsevier Ltd.

Body density affects stroke patterns in Baikal seals.

PubMed

Watanabe, Yuuki; Baranov, Eugene A; Sato, Katsufumi; Naito, Yasuhiko; Miyazaki, Nobuyuki

2006-09-01

Buoyancy is one of the primary external forces acting on air-breathing divers and it can affect their swimming energetics. Because the body composition of marine mammals (i.e. the relative amounts of lower-density lipid and higher-density lean tissue) varies individually and seasonally, their buoyancy also fluctuates widely, and individuals would be expected to adjust their stroke patterns during dives accordingly. To test this prediction, we attached acceleration data loggers to four free-ranging Baikal seals Phoca sibirica in Lake Baikal and monitored flipper stroking activity as well as swimming speed, depth and inclination of the body axis (pitch). In addition to the logger, one seal (Individual 4) was equipped with a lead weight that was jettisoned after a predetermined time period so that we had a set of observations on the same individual with different body densities. These four data sets revealed the general diving patterns of Baikal seals and also provided direct insights into the influence of buoyancy on these patterns. Seals repeatedly performed dives of a mean duration of 7.0 min (max. 15.4 min), interrupted by a mean surface duration of 1.2 min. Dive depths were 66 m on average, but varied substantially, with a maximum depth of 324 m. The seals showed different stroke patterns among individuals; some seals stroked at lower rates during descent than ascent, while the others had higher stroke rates during descent than ascent. When the lead weight was detached from Individual 4, the seal increased its stroke rate in descent by shifting swimming mode from prolonged glides to more stroke-and-glide swimming, and decreased its stroke rate in ascent by shifting from continuous stroking to stroke-and-glide swimming. We conclude that seals adopt different stroke patterns according to their individual buoyancies. We also demonstrate that the terminal speed reached by Individual 4 during prolonged glide in descent depended on its total buoyancy and pitch, with higher speeds reached in the weighted condition and at steeper pitch. A simple physical model allowed us to estimate the body density of the seal from the speed and pitch (1,027-1,046 kg m(-3), roughly corresponding to 32-41% lipid content, for the weighted condition; 1,014-1,022 kg m(-3), 43-47% lipid content, for the unweighted condition).

Mayolenes: Labile defensive lipids from the glandular hairs of a caterpillar (Pieris rapae)

PubMed Central

Smedley, Scott R.; Schroeder, Frank C.; Weibel, Douglas B.; Meinwald, Jerrold; Lafleur, Katie A.; Renwick, J. Alan; Rutowski, Ronald; Eisner, Thomas

2002-01-01

Larvae of the European cabbage butterfly, Pieris rapae (Pieridae), are beset with glandular hairs, bearing droplets of a clear oily secretion at their tip. The fluid consists primarily of a series of chemically labile, unsaturated lipids, the mayolenes, which are derived from 11-hydroxylinolenic acid. In bioassays with the ant Crematogaster lineolata, the secretion was shown to be potently deterrent, indicating that the fluid plays a defensive role in nature. PMID:11997469

Basal deposits and drusen in eyes with age-related maculopathy: evidence for solid lipid particles.

PubMed

Curcio, Christine A; Presley, J Brett; Millican, C Leigh; Medeiros, Nancy E

2005-06-01

Neutral lipid, including esterified cholesterol, and apolipoproteins B and E are abundant in basal deposits and drusen of aged and age-related maculopathy (ARM) eyes. The principal component of basal linear deposit (BlinD), a specific ARM lesion, is membranous debris, which if actually derived from membranes cannot account for extracellular neutral lipid. We therefore used a lipid-preserving ultrastructural method to obtain improved images of membranous debris. Maculas from 44 human donors (71-96 yr) were preserved <7.5 hr after death. Blocks were post-fixed in 2% osmium or osmium-tannic acid-paraphenylenediamine (OTAP) to preserve neutral lipid for thin-section transmission electron microscopic (TEM) examination. Solid particles identified by OTAP were considered closest to the in vivo state of extracellular lipids. Micrographs were examined for intermediate forms, with greatest weight given to comparable images from different preparations of same or fellow eyes. Twenty eyes of older adults (12 with ARM including fellows treated with photodynamic and radiation therapies) had adequately preserved extracellular lipid. The exterior surface of membranous debris was thicker and more electron-dense than basal infoldings of retinal pigment epithelium (RPE) cells. By OTAP, individual membranous debris profiles were solid (diameters, 80-200 nm) and formed tracks across or aggregations within basal laminar deposits. Solid particles and/or pools of neutral lipid were visible in BlinD and drusen. When processed to preserve lipid, membranous debris resembles neither membranes of surrounding cells nor vesicles possessing aqueous interiors but rather solid particles. These results are consistent with recent evidence implicating lipoprotein particles of intra-ocular origin as a potential source of neutral lipids, including esterified cholesterol, in the specific lesions of ARM.

Efficient encapsulation of antisense oligonucleotides in lipid vesicles using ionizable aminolipids: formation of novel small multilamellar vesicle structures.

PubMed

Semple, S C; Klimuk, S K; Harasym, T O; Dos Santos, N; Ansell, S M; Wong, K F; Maurer, N; Stark, H; Cullis, P R; Hope, M J; Scherrer, P

2001-02-09

Typical methods used for encapsulating antisense oligodeoxynucleotides (ODN) and plasmid DNA in lipid vesicles result in very low encapsulation efficiencies or employ cationic lipids that exhibit unfavorable pharmacokinetic and toxicity characteristics when administered intravenously. In this study, we describe and characterize a novel formulation process that utilizes an ionizable aminolipid (1,2-dioleoyl-3-dimethylammonium propane, DODAP) and an ethanol-containing buffer system for encapsulating large quantities (0.15--0.25 g ODN/g lipid) of polyanionic ODN in lipid vesicles. This process requires the presence of up to 40% ethanol (v/v) and initial formulation at acidic pH values where the DODAP is positively charged. In addition, the presence of a poly(ethylene glycol)-lipid was required during the formulation process to prevent aggregation. The 'stabilized antisense-lipid particles' (SALP) formed are stable on adjustment of the external pH to neutral pH values and the formulation process allows encapsulation efficiencies of up to 70%. ODN encapsulation was confirmed by nuclease protection assays and (31)P NMR measurements. Cryo-electron microscopy indicated that the final particles consisted of a mixed population of unilamellar and small multilamellar vesicles (80--140 nm diameter), the relative proportion of which was dependent on the initial ODN to lipid ratio. Finally, SALP exhibited significantly enhanced circulation lifetimes in mice relative to free antisense ODN, cationic lipid/ODN complexes and SALP prepared with quaternary aminolipids. Given the small particle sizes and improved encapsulation efficiency, ODN to lipid ratios, and circulation times of this formulation compared to others, we believe SALP represent a viable candidate for systemic applications involving nucleic acid therapeutics.

Presence and persistence of a highly ordered lipid phase state in the avian stratum corneum.

PubMed

Champagne, Alex M; Pigg, Victoria A; Allen, Heather C; Williams, Joseph B

2018-06-07

To survive high temperatures in a terrestrial environment, animals must effectively balance evaporative heat loss and water conservation. In passerine birds, cutaneous water loss (CWL) is the primary avenue of water loss at thermoneutral temperatures and increases slightly as ambient temperature increases, indicating a change in the permeability of the skin. In the stratum corneum (SC), the outermost layer of the skin, lipids arranged in layers called lamellae serve as the primary barrier to CWL in birds. The permeability of these lamellae depends in large part on the ability of lipid molecules to pack closely together in an ordered orthorhombic phase state. However, as temperature increases, lipids of the SC become more disordered, and may pack in more permeable hexagonal or liquid crystalline phase states. In this study, we used Fourier transform infrared spectroscopy to monitor the phase state of lipids in the SC of house sparrows ( Passer domesticus ) at skin temperatures ranging from 25 to 50°C. As temperature increased, lipids became slightly more disordered, but remained predominantly in the orthorhombic phase, consistent with the small increase in CWL observed in house sparrows as ambient temperature increases. These results differ considerably from studies on mammalian SC, which find a predominantly hexagonal arrangement of lipids at temperatures above 37°C, and the increased order in avian SC may be explained by longer lipid chain length, scarcity of cholesterol and the presence of cerebrosides. Our results lend further insight into the arrangement and packing of individual lipid molecules in avian SC. © 2018. Published by The Company of Biologists Ltd.

Unusual heme iron-lipid acyl chain coordination in Escherichia coli flavohemoglobin.

PubMed

D'Angelo, Paola; Lucarelli, Debora; della Longa, Stefano; Benfatto, Maurizio; Hazemann, Jean Louis; Feis, Alessandro; Smulevich, Giulietta; Ilari, Andrea; Bonamore, Alessandra; Boffi, Alberto

2004-06-01

Escherichia coli flavohemoglobin is endowed with the notable property of binding specifically unsaturated and/or cyclopropanated fatty acids both as free acids or incorporated into a phospholipid molecule. Unsaturated or cyclopropanated fatty acid binding to the ferric heme results in a spectral change observed in the visible absorption, resonance Raman, extended x-ray absorption fine spectroscopy (EXAFS), and x-ray absorption near edge spectroscopy (XANES) spectra. Resonance Raman spectra, measured on the flavohemoglobin heme domain, demonstrate that the lipid (linoleic acid or total lipid extracts)-induced spectral signals correspond to a transition from a five-coordinated (typical of the ligand-free protein) to a hexacoordinated, high spin heme iron. EXAFS and XANES measurements have been carried out both on the lipid-free and on the lipid-bound protein to assign the nature of ligand in the sixth coordination position of the ferric heme iron. EXAFS data analysis is consistent with the presence of a couple of atoms in the sixth coordination position at 2.7 A in the lipid-bound derivative (bonding interaction), whereas a contribution at 3.54 A (nonbonding interaction) can be singled out in the lipid-free protein. This last contribution is assigned to the CD1 carbon atoms of the distal LeuE11, in full agreement with crystallographic data on the lipid-free protein at 1.6 A resolution obtained in the present work. Thus, the contributions at 2.7 A distance from the heme iron are assigned to a couple of carbon atoms of the lipid acyl chain, possibly corresponding to the unsaturated carbons of the linoleic acid.

With medium-chain triglycerides, higher and faster oxygen radical production by stimulated polymorphonuclear leukocytes occurs.

PubMed

Kruimel, J W; Naber, A H; Curfs, J H; Wenker, M A; Jansen, J B

2000-01-01

Parenteral lipid emulsions are suspected of suppressing the immune function. However, study results are contradictory and mainly concern the conventional long-chain triglyceride emulsions. Polymorphonuclear leukocytes were preincubated with parenteral lipid emulsions. The influence of the lipid emulsions on the production of oxygen radicals by these stimulated leukocytes was studied by measuring chemiluminescence. Three different parenteral lipid emulsions were tested: long-chain triglycerides, a physical mixture of medium- and long-chain triglycerides, and structured triglycerides. Structured triglycerides consist of triglycerides where the medium- and long-chain fatty acids are attached to the same glycerol molecule. Stimulated polymorphonuclear leukocytes preincubated with the physical mixture of medium- and long-chain triglycerides showed higher levels of oxygen radicals (p < .005) and faster production of oxygen radicals (p < .005) compared with polymorphonuclear leukocytes preincubated with long-chain triglycerides or structured triglycerides. Additional studies indicated that differences in results of various lipid emulsions were not caused by differences in emulsifier. The overall production of oxygen radicals was significantly lower after preincubation with the three lipid emulsions compared with controls without lipid emulsion. A physical mixture of medium- and long-chain triglycerides induced faster production of oxygen radicals, resulting in higher levels of oxygen radicals, compared with long-chain triglycerides or structured triglycerides. This can be detrimental in cases where oxygen radicals play either a pathogenic role or a beneficial one, such as when rapid phagocytosis and killing of bacteria is needed. The observed lower production of oxygen radicals by polymorphonuclear leukocytes in the presence of parenteral lipid emulsions may result in immunosuppression by these lipids.

Turnover of muscle lipids and response to exercise differ between neutral and polar fractions in a model songbird, the zebra finch.

PubMed

Carter, Wales A; Cooper-Mullin, Clara; McWilliams, Scott R

2018-03-19

The turnover rates of tissues and their constituent molecules give us insights into animals' physiological demands and their functional flexibility over time. Thus far, most studies of this kind have focused on protein turnover, and few have considered lipid turnover despite an increasing appreciation of the functional diversity of this class of molecules. We measured the turnover rates of neutral and polar lipids from the pectoralis muscles of a model songbird, the zebra finch ( Taeniopygia guttata , N =65), in a 256 day C 3 /C 4 diet shift experiment, with tissue samples taken at 10 time points. We also manipulated the physiological state of a subset of these birds with a 10 week flight training regimen to test the effect of exercise on lipid turnover. We measured lipid δ 13 C values via isotope ratio mass spectrometry (IRMS) and estimated turnover in different fractions and treatment groups with non-linear mixed-effect regression. We found a significant difference between the mean retention times (τ) of neutral and polar lipids ( t 119 =-2.22, P =0.028), with polar lipids (τ=11.80±1.28 days) having shorter retention times than neutral lipids (τ=19.47±3.22 days). When all birds were considered, we also found a significant decrease in the mean retention time of polar lipids in exercised birds relative to control birds (difference=-2.2±1.83 days, t 56 =-2.37, P =0.021), but not neutral lipids (difference=4.2± 7.41 days, t 56 =0.57, P =0.57). A larger, more variable neutral lipid pool and the exposure of polar lipids in mitochondrial membranes to oxidative damage and increased turnover provide mechanisms consistent with our results. © 2018. Published by The Company of Biologists Ltd.

Dendrimer Interactions with Lipid Bilayer: Comparison of Force Field and Effect of Implicit vs Explicit Solvation.

PubMed

Kanchi, Subbarao; Gosika, Mounika; Ayappa, K G; Maiti, Prabal K

2018-06-13

The understanding of dendrimer interactions with cell membranes has great importance in drug/gene delivery based therapeutics. Although molecular simulations have been used to understand the nature of dendrimer interactions with lipid membranes, its dependency on available force field parameters is poorly understood. In this study, we have carried out fully atomistic molecular dynamics (MD) simulations of a protonated G3 poly(amido amine) (PAMAM) dendrimer-dimyristoylphosphatidylcholine (DMPC) lipid bilayer complex using three different force fields (FFs) namely, CHARMM, GAFF, and GROMOS in the presence of explicit water to understand the structure of the lipid-dendrimer complex and nature of their interaction. CHARMM and GAFF dendrimers initially in contact with the lipid head groups were found to move away from the lipid bilayer during the course of simulation; however, the dendrimer remained strongly bound to the lipid head groups with the GROMOS FF. Potential of the mean force (PMF) computations of the dendrimer along the bilayer normal showed a repulsive barrier (∼20 kcal/mol) between dendrimer and lipid bilayer in the case of CHARMM and GAFF force fields. In contrast, an attractive interaction (∼40 kcal/mol) is obtained with the GROMOS force field, consistent with experimental observations of membrane binding observed with lower generation G3 PAMAM dendrimers. This difference with the GROMOS dendrimer is attributed to the strong dendrimer-lipid interaction and lowered surface hydration of the dendrimer. Assessing the role of solvent, we find that the CHARMM and GAFF dendrimers strongly bind to the lipid bilayer with an implicit solvent (Generalized Born) model, whereas binding is not observed with explicit water (TIP3P). The opposing nature of dendrimer-membrane interactions in the presence of explicit and implicit solvents demonstrates that hydration effects play an important role in modulating the dendrimer-lipid interaction warranting a case for refinement of the existing dendrimer/lipid force fields.

A Molecular Probe for the Detection of Polar Lipids in Live Cells

PubMed Central

Bader, Christie A.; Shandala, Tetyana; Carter, Elizabeth A.; Ivask, Angela; Guinan, Taryn; Hickey, Shane M.; Werrett, Melissa V.; Wright, Phillip J.; Simpson, Peter V.; Stagni, Stefano; Voelcker, Nicolas H.; Lay, Peter A.; Massi, Massimiliano; Brooks, Douglas A.

2016-01-01

Lipids have an important role in many aspects of cell biology, including membrane architecture/compartment formation, intracellular traffic, signalling, hormone regulation, inflammation, energy storage and metabolism. Lipid biology is therefore integrally involved in major human diseases, including metabolic disorders, neurodegenerative diseases, obesity, heart disease, immune disorders and cancers, which commonly display altered lipid transport and metabolism. However, the investigation of these important cellular processes has been limited by the availability of specific tools to visualise lipids in live cells. Here we describe the potential for ReZolve-L1™ to localise to intracellular compartments containing polar lipids, such as for example sphingomyelin and phosphatidylethanolamine. In live Drosophila fat body tissue from third instar larvae, ReZolve-L1™ interacted mainly with lipid droplets, including the core region of these organelles. The presence of polar lipids in the core of these lipid droplets was confirmed by Raman mapping and while this was consistent with the distribution of ReZolve-L1™ it did not exclude that the molecular probe might be detecting other lipid species. In response to complete starvation conditions, ReZolve-L1™ was detected mainly in Atg8-GFP autophagic compartments, and showed reduced staining in the lipid droplets of fat body cells. The induction of autophagy by Tor inhibition also increased ReZolve-L1™ detection in autophagic compartments, whereas Atg9 knock down impaired autophagosome formation and altered the distribution of ReZolve-L1™. Finally, during Drosophila metamorphosis fat body tissues showed increased ReZolve-L1™ staining in autophagic compartments at two hours post puparium formation, when compared to earlier developmental time points. We concluded that ReZolve-L1™ is a new live cell imaging tool, which can be used as an imaging reagent for the detection of polar lipids in different intracellular compartments. PMID:27551717

Maternal Serum Lipid, Estradiol, and Progesterone Levels in Pregnancy, and the Impact of Placental and Hepatic Pathologies

PubMed Central

Pecks, U.; Rath, W.; Kleine-Eggebrecht, N.; Maass, N.; Voigt, F.; Goecke, T. W.; Mohaupt, M. G.; Escher, G.

2016-01-01

Objective: Lipids and steroid hormones are closely linked. While cholesterol is the substrate for (placental) steroid hormone synthesis, steroid hormones regulate hepatic lipid production. The aim of this study was to quantify circulating steroid hormones and lipid metabolites, and to characterize their interactions in normal and pathological pregnancies with a focus on hepatic and placental pathologies. Methods: A total of 216 serum samples were analyzed. Group A consisted of 32 patients with uncomplicated pregnancies who were analyzed at three different time-points in pregnancy (from the first through the third trimester) and once post partum. Group B consisted of 36 patients (24th to 42nd week of gestation) with pregnancy pathologies (IUGR n = 10, preeclampsia n = 13, HELLP n = 6, intrahepatic cholestasis n = 7) and 31 controls with uncomplicated pregnancies. Steroid profiles including estradiol, progesterone, and dehydroepiandrosterone were measured by GC-MS and compared with lipid concentrations. Results: In Group A, cholesterol and triglycerides correlated positively with estradiol (cholesterol ρ = 0.50, triglycerides ρ = 0.57) and progesterone (ρ = 0.49, ρ = 0.53) and negatively with dehydroepiandrosterone (ρ = − 0.47, ρ = − 0.38). Smoking during pregnancy affected estradiol concentrations, leading to lower levels in the third trimester compared to non-smoking patients (p < 0.05). In Group B, cholesterol levels were found to be lower in IUGR pregnancies and in patients with HELLP syndrome compared to controls (p < 0.05). Steroid hormone concentrations of estradiol (p < 0.05) and progesterone (p < 0.01) were lower in pregnancies with IUGR. Discussion: Lipid and steroid levels were affected most in IUGR pregnancies, while only minor changes in concentrations were observed for other pregnancy-related disorders. Each of the analyzed entities displayed specific changes. However, since the changes were most obvious in pregnancies complicated by IUGR and only minor changes were observed in pregnancies where patients had impaired liver function, our data suggests that placental rather than maternal hepatic function strongly determines lipid and steroid levels in pregnancy. PMID:27582578

Distinctive accumulation patterns of heavy metals in Sardinella aurita (Clupeidae) and Mugil cephalus (Mugilidae) tissues.

PubMed

Annabi, Ali; El Mouadeb, Rahma; Herrel, Anthony

2018-01-01

The present study assessed the impact of metal pollution on two widely consumed types of wild fish Sardinella aurita and Mugil cephalus captured from the Gulf of Gabes (Tunisia) which is currently experiencing acute environmental problems. A study of the Cd, Cu, Zn, and Pb levels present in the studied site and vital in fish tissues (gills, liver, gonad, and muscle) was undertaken. As expected, muscle, liver, and gonad tissues contained the highest concentrations of all metals except for Zn. The metal levels showed a significant variation of accumulation between species with overall effects of the tested tissues. In addition, the results address the significant effects of the species/tissue interaction. Liver sections showed structural alterations consisting mainly of a significant desquamation of the tissue, a fibroblast proliferation, and a lipid droplet accumulation in both species. Additionally, the presence of skeletal abnormalities affecting the vertebral column was observed in the M. cephalus specimens. As a whole, our data provide the first evidence of distinctive metal accumulation patterns in vital fish tissues as well as the interspecific difference that can be correlated with the biological habits of the two selected models, S. aurita and M. cephalus, known respectively as pelagic and benthopelagic species.

Microgenomic analysis reveals cell type-specific gene expression patterns between ray and fusiform initials within the cambial meristem of Populus.

PubMed

Goué, Nadia; Lesage-Descauses, Marie-Claude; Mellerowicz, Ewa J; Magel, Elisabeth; Label, Philippe; Sundberg, Björn

2008-01-01

The vascular cambium is the meristem in trees that produce wood. This meristem consists of two types of neighbouring initials: fusiform cambial cells (FCCs), which give rise to the axial cell system (i.e. fibres and vessel elements), and ray cambial cells (RCCs), which give rise to rays. There is little molecular information on the mechanisms whereby the differing characteristics of these neighbouring cells are maintained. A microgenomic approach was adopted in which the transcriptomes of FCCs and RCCs dissected out from the cambial meristem of poplar (Populus trichocarpa x Populus deltoïdes var. Boelare) were analysed, and a transcriptional database for these two cell types established. Photosynthesis genes were overrepresented in RCCs, providing molecular support for the presence of photosynthetic systems in rays. Genes that putatively encode transporters (vesicle, lipid and metal ion transporters and aquaporins) in RCCs were also identified. In addition, many cell wall-related genes showed cell type-specific expression patterns. Notably, genes involved in pectin metabolism and xyloglucan metabolism were overrepresented in RCCs and FCCs, respectively. The results demonstrate the use of microgenomics to reveal differences in biological processes in neighbouring meristematic cells, and to identify key genes involved in these processes.

Residential greenness and blood lipids in children: A longitudinal analysis in GINIplus and LISAplus.

PubMed

Markevych, Iana; Standl, Marie; Sugiri, Dorothea; Harris, Carla; Maier, Werner; Berdel, Dietrich; Heinrich, Joachim

2016-11-01

There is some evidence of decreased cardiovascular disease (CVD) mortality and morbidity among adults residing in greener places. Among others, blood lipids are well established risk factors for CVD. In our previous study, we observed the inverse association between greenness and blood pressure in 10-year-old children. In the current study, we investigated whether there is also a link between residential greenness and blood lipids in 10- and 15-year-old children. Complete data on blood lipids (total cholesterol, HDL, LDL and triglyceride), residential greenness (NDVI in 100-m, 300- and 500-m buffers around residences) and confounders were available for 1,552 participants at 10 and 15 years of age, residing in two study areas of two German birth cohorts - GINIplus and LISAplus. Longitudinal associations between NDVI and blood lipids were assessed by generalized estimation equations. No associations were observed between residential greenness in any of the chosen buffers and blood lipids in children (e.g., change in blood lipids per interquartile increase in NDVI in 100-m buffer for total cholesterol and LDL: means ratio=1.00 (95% confidence interval: 0.99-1.01), for triglyceride: 0.98 (0.96-1.00)). No area- or sex-varying effects were evident. Change of the residence between 10 and 15 years also did not yield any consistent associations. There is no evidence of an association between greenness and blood lipids in 10- and 15-years old children. Copyright © 2016 Elsevier Inc. All rights reserved.

The role of negatively charged lipids in lysosomal phospholipase A2 function

PubMed Central

Abe, Akira; Shayman, James A.

2009-01-01

Lysosomal phospholipase A2 (LPLA2) is characterized by increased activity toward zwitterionic phospholipid liposomes containing negatively charged lipids under acidic conditions. The effect of anionic lipids on LPLA2 activity was investigated. Mouse LPLA2 activity was assayed as C2-ceramide transacylation. Sulfatide incorporated into liposomes enhanced LPLA2 activity under acidic conditions and was weakened by NaCl or increased pH. Amiodarone, a cationic amphiphilic drug, reduced LPLA2 activity. LPLA2 exhibited esterase activity when p-nitro-phenylbutyrate (pNPB) was used as a substrate. Unlike the phospholipase A2 activity, the esterase activity was detected over wide pH range and not inhibited by NaCl or amiodarone. Presteady-state kinetics using pNPB were consistent with the formation of an acyl-enzyme intermediate. C2-ceramide was an acceptor for the acyl group of the acyl-enzyme but was not available as the acyl group acceptor when dispersed in liposomes containing amiodarone. Cosedimentation of LPLA2 with liposomes was enhanced in the presence of sulfatide and was reduced by raising NaCl, amiodarone, or pH in the reaction mixture. LPLA2 adsorption to negatively charged lipid membrane surfaces through an electrostatic attraction, therefore, enhances LPLA2 enzyme activity toward insoluble substrates. Thus, anionic lipids present within lipid membranes enhance the rate of phospholipid hydrolysis by LPLA2 at lipid-water interfaces.—Abe, A., and J. A. Shayman. The role of negatively charged lipids in lysosomal phospholipase A2 function. PMID:19321879

Molecular mechanism for lipid flip-flops.

PubMed

Gurtovenko, Andrey A; Vattulainen, Ilpo

2007-12-06

Transmembrane lipid translocation (flip-flop) processes are involved in a variety of properties and functions of cell membranes, such as membrane asymmetry and programmed cell death. Yet, flip-flops are one of the least understood dynamical processes in membranes. In this work, we elucidate the molecular mechanism of pore-mediated transmembrane lipid translocation (flip-flop) acquired from extensive atomistic molecular dynamics simulations. On the basis of 50 successful flip-flop events resolved in atomic detail, we demonstrate that lipid flip-flops may spontaneously occur in protein-free phospholipid membranes under physiological conditions through transient water pores on a time scale of tens of nanoseconds. While the formation of a water pore is induced here by a transmembrane ion density gradient, the particular way by which the pore is formed is irrelevant for the reported flip-flop mechanism: the appearance of a transient pore (defect) in the membrane inevitably leads to diffusive translocation of lipids through the pore, which is driven by thermal fluctuations. Our findings strongly support the idea that the formation of membrane defects in terms of water pores is the rate-limiting step in the process of transmembrane lipid flip-flop, which, on average, requires several hours. The findings are consistent with available experimental and computational data and provide a view to interpret experimental observations. For example, the simulation results provide a molecular-level explanation in terms of pores for the experimentally observed fact that the exposure of lipid membranes to electric field pulses considerably reduces the time required for lipid flip-flops.

An observational study of sequential protein-sparing, very low-calorie ketogenic diet (Oloproteic diet) and hypocaloric Mediterranean-like diet for the treatment of obesity.

PubMed

Castaldo, Giuseppe; Monaco, Luigi; Castaldo, Laura; Galdo, Giovanna; Cereda, Emanuele

2016-09-01

The impact of a rehabilitative multi-step dietary program consisting in different diets has been scantily investigated. In an open-label study, 73 obese patients underwent a two-phase weight loss (WL) program: a 3-week protein-sparing, very low-calorie, ketogenic diet (<500 kcal/day; Oloproteic(®) Diet) and a 6-week hypocaloric (25-30 kcal/kg of ideal body weight/day), low glycemic index, Mediterranean-like diet (hypo-MD). Both phases improved visceral adiposity, liver enzymes, GH levels, blood pressure and glucose and lipid metabolism. However, the hypo-MD was responsible for a re-increase in blood lipids and glucose tolerance parameters. Changes in visceral adiposity and glucose control-related variables were more consistent in patients with metabolic syndrome. However, in these patients the hypo-MD did not result in a consistent re-increase in glucose control-related variables. A dietary program consisting in a ketogenic regimen followed by a balanced MD appeared to be feasible and efficacious in reducing cardiovascular risk, particularly in patients with metabolic syndrome.

Nixtamalization Process Affects Resistant Starch Formation and Glycemic Index of Tamales.

PubMed

Mariscal-Moreno, Rosa María; de Dios Figueroa Cárdenas, Juan; Santiago-Ramos, David; Rayas-Duarte, Patricia; Veles-Medina, José Juan; Martínez-Flores, Héctor Eduardo

2017-05-01

Tamales were prepared with 3 nixtamalization processes (traditional, ecological, and classic) and evaluated for chemical composition, starch properties, and glycemic index. Resistant starch (RS) in tamales increased 1.6 to 3.7 times compared to raw maize. This increment was due to the starch retrogradation (RS3) and amylose-lipid complexes (RS5) formation. Tamales elaborated with classic and ecological nixtamalization processes exhibited the highest total, soluble and insoluble dietary fiber content, and the highest RS content and lower in vivo glycemic index compared to tamales elaborated with traditional nixtamalization process. Thermal properties of tamales showed 3 endotherms: amylopectin retrogradation (42.7 to 66.6 °C), melting of amylose lipid complex type I (78.8 to 105.4), and melting of amylose-lipid complex type II (110.7 to 129.7). Raw maize exhibited X-ray diffraction pattern type A, after nixtamalization and cooking of tamales it changed to V-type polymorph structure, due to amylose-lipid complexes formation. Tamales from ecological nixtamalization processes could represent potential health benefits associated with the reduction on blood glucose response after consumption. © 2017 Institute of Food Technologists®.

Dynamic pattern generation in cell membranes: Current insights into membrane organization.

PubMed

Raghunathan, Krishnan; Kenworthy, Anne K

2018-05-09

It has been two decades since the lipid raft hypothesis was first presented. Even today, whether these nanoscale cholesterol-rich domains are present in cell membranes is not completely resolved. However, especially in the last few years, a rich body of literature has demonstrated both the presence and the importance of non-random distribution of biomolecules on the membrane, which is the focus of this review. These new developments have pushed the experimental limits of detection and have brought us closer to observing lipid domains in the plasma membrane of live cells. Characterization of biomolecules associated with lipid rafts has revealed a deep connection between biological regulation and function and membrane compositional heterogeneities. Finally, tantalizing new developments in the field have demonstrated that lipid domains might not just be associated with the plasma membrane of eukaryotes but could potentially be a ubiquitous membrane-organizing principle in several other biological systems. This article is part of a Special Issue entitled: Emergence of Complex Behavior in Biomembranes edited by Marjorie Longo. Copyright © 2018. Published by Elsevier B.V.

Utilization of ketone bodies by chick brain and spinal cord during embryonic and postnatal development.

PubMed

Linares, A; Caamaño, G J; Diaz, R; Gonzalez, F J; Garcia-Peregrin, E

1993-10-01

Lipid synthesis from acetoacetate and 3-hydroxybutyrate was studied in chick embryo from 15 to 21 days and in chick neonate from 1 to 21 days. Embryonic spinal cord showed higher ability than brain to incorporate acetoacetate into total lipids, although a sharp decrease was found at hatching. 3-Hydroxybutyrate incorporation into total lipids was also higher in spinal cord than in brain, especially during the embryonic period. Phospholipids were the main lipids formed in both tissues from both precursors. An appreciable percentage of radioactivity was also recovered as free cholesterol, especially during the embryonic phase. The developmental patterns of amino acid synthesis from acetoacetate and 3-hydroxybutyrate were similar in both tissues: a clear increase after hatching was followed by a decrease at day 4 of neonatal life. Acetoacetate was a better substrate for amino acid synthesis than 3-hydroxybutyrate during the embryonic development in both tissues. Oxidation of both precursors to CO2 strongly decreased between 15 and 21 days of embryonic development both in brain and spinal cord.

INF-gamma rearranges membrane topography of MHC-I and ICAM-1 in colon carcinoma cells.

PubMed

Bacsó, Zsolt; Bene, László; Damjanovich, László; Damjanovich, Sándor

2002-01-18

Flow-cytometric fluorescence energy transfer (FCET) measurements between fluorescently labeled cell surface MHC-I and ICAM-1 molecules indicated similar receptor patterns in the plasma membrane of interferon-gamma (INF-gamma)-treated colon carcinoma cells as those observed earlier at the surface of lymphoid cells. INF-gamma activation significantly increased the density of MHC-I and ICAM-1 proteins in the membrane. This increase in receptor density was accompanied by decreased proximity level of the homo-associated MHC-I receptors. Hetero-association of MHC-I and ICAM-1 molecules was increased by INF-gamma treatment. INF-gamma changed neither hetero- nor homo-association of transferrin receptors. By staining the sphingomyelin/cholesterol-enriched lipid microdomains with fluorescently labeled cholera toxin B subunit, we found an increase in the amount of lipid-raft associated G(M1)-gangliosides due to INF-gamma treatment. Confocal microscopic results and FCET measurements show that MHC-I and ICAM-1 are components of G(M1)-ganglioside containing lipid-rafts and also support an increase in the size of these lipid-rafts upon INF-gamma treatment.

Refeeding meal-fed rats increases lipoprotein lipase activity and deposition of dietary [14C]lipid in white adipose tissue and decreases oxidation to 14CO2. The role of undernutrition.

PubMed Central

Cruz, M L; Williamson, D H

1992-01-01

Meal-fed (3 h) rats had a decreased food intake, body weight and carcass fat compared with rats fed ad libitum. On refeeding a chow meal containing [1-14C]triolein, the production of 14CO2 was lower (45%) and the accumulation of carcass [14C]lipid higher (37%) in the meal-fed rats. There was higher lipoprotein lipase activity and greater accumulation of [14C]lipid in the epididymal and subcutaneous adipose-tissue depots of the meal-fed rats. In contrast, heparin-releasable lipoprotein lipase was not increased in perfused hearts of meal-fed rats on refeeding. Return of meal-fed rats to feeding ad libitum reversed these changes before the restoration of body weight or carcass fat. Evidence is presented that decreased dietary intake rather than meal pattern is an important determinant of the alterations in adipose lipid metabolism in the meal-fed rat in response to a meal. PMID:1497615

Sensitive assay, based on hydroxy fatty acids from lipopolysaccharide lipid A, for Gram-negative bacteria in sediments.

PubMed Central

Parker, J H; Smith, G A; Fredrickson, H L; Vestal, J R; White, D C

1982-01-01

Biochemical measures have provided insight into the biomass and community structure of sedimentary microbiota without the requirement of selection by growth or quantitative removal from the sediment grains. This study used the assay of the hydroxy fatty acids released from the lipid A of the lipopolysaccharide in sediments to provide an estimate of the gram-negative bacteria. The method was sensitive to picomolar amounts of hydroxy fatty acids. The recovery of lipopolysaccharide hydroxy fatty acids from organisms added to sediments was quantitative. The lipids were extracted from the sediments with single-phase chloroform-methanol extraction. The lipid-extraction residue was hydrolyzed in 1 N HCl, and the hydroxy fatty acids of the lipopolysaccharide were recovered in chloroform for analysis by gas-liquid chromatography. This method proved to be about fivefold more sensitive than the classical phenol-water or trichloroacetic acid methods when applied to marine sediments. By examination of the patterns of hydroxy fatty acids, it was also possible to help define the community structure of the sedimentary gram-negative bacteria. PMID:6817712

D-stat culture for studying the metabolic shifts from oxidative metabolism to lipid accumulation and citric acid production in Yarrowia lipolytica.

PubMed

Ochoa-Estopier, Abril; Guillouet, Stéphane E

2014-01-20

Lipid accumulation in oleaginous yeasts is triggered by nutrient imbalance in the culture medium between the carbon source in excess and the nitrogen source in limiting concentration. However Yarrowia lipolytica when cultivated on glucose as the sole carbon source, mainly produces citric acid upon nitrogen limitation over lipid accumulation (only 5-10% triacylglycerol). Therefore for developing bioprocess for the production of triacylglycerol from renewable carbon source as glucose it is of first importance to control this imbalance in order to avoid citric acid production during TAG accumulation. Using D-stat cultivation system, where the N/C was linearly decreased using a constant change rate we were able to identify the N/C ratio inducing TAG accumulation (0.085NmolCmol(-1)) and citric acid (0.021NmolCmol(-1)). We therefore demonstrated that it was possible to accumulate lipids without excretion citric acid as long as the N/C was within this indicated range. Moreover enzyme specific activities measurement during the D-stat indicated that ATP-citrate lyase, malic enzyme and acetyl-coA carboxylase were strongly induced at the onset of lipid accumulation and showed different patterns when citric acid was excreted. Our results give relevant information for future industrial bioprocess development concerning the production of lipids using renewable carbohydrate substrates as an alternative way to produce synthons for fuel or chemical industry. By controlling the N/C over the fermentation process on glucose Y. lipolytica can accumulate lipids without excreting citric acid. Copyright © 2013 Elsevier B.V. All rights reserved.

Transport and uptake effects of marine complex lipid liposomes in small intestinal epithelial cell models.

PubMed

Du, Lei; Yang, Yu-Hong; Xu, Jie; Wang, Yu-Ming; Xue, Chang-Hu; Kurihara, Hideyuki; Takahashi, Koretaro

2016-04-01

Nowadays, marine complex lipids, including starfish phospholipids (SFP) and cerebrosides (SFC) separated from Asterias amurensis as well as sea cucumber phospholipids (SCP) and cerebrosides (SCC) isolated from Cucumaria frondosa, have received much attention because of their potent biological activities. However, little information is known on the transport and uptake of these lipids in liposome forms in small intestinal cells. Therefore, this study was undertaken to investigate the effects of these complex lipid liposomes on transport and uptake in Caco-2 and M cell monolayer models. The results revealed that SFP and SCP contained 42% and 47.9% eicosapentaenoic acid (EPA), respectively. The average particle sizes of liposomes prepared in this study were from 169 to 189 nm. We found that the transport of the liposomes across the M cell monolayer model was much higher than the Caco-2 cell monolayer model. The liposomes consisting of SFP or SCP showed significantly higher transport and uptake than soy phospholipid (soy-PL) liposomes in both Caco-2 and M cell monolayer models. Our results also exhibited that treatment with 1 mM liposomes composed of SFP or SCP for 3 h tended to increase the EPA content in phospholipid fractions of both differentiated Caco-2 and M cells. Moreover, it was also found that the hybrid liposomes consisting of SFP/SFC/cholesterol (Chol) revealed higher transport and uptake across the M cell monolayer in comparison with other liposomes. Furthermore, treatment with SFP/SFC/Chol liposomes could notably decrease the trans-epithelial electrical resistance (TEER) values of Caco-2 and M cell monolayers. The present data also showed that the cell viability of differentiated Caco-2 and M cells was not affected after the treatment with marine complex lipids or soy-PL liposomes. Based on the data in this study, it was suggested that marine complex lipid liposomes exhibit prominent transport and uptake in small intestinal epithelial cell models.

Origin of lipid biomarkers in mud volcanoes from the Alboran Sea, western Mediterranean

NASA Astrophysics Data System (ADS)

López-Rodríguez, C.; Stadnitskaia, A.; De Lange, G. J.; Martínez-Ruíz, F.; Comas, M.; Sinninghe Damsté, J. S.

2013-11-01

Mud volcanoes (MVs) are the most prominent indicators of active methane/hydrocarbon venting at the seafloor on both passive and active continental margins. Their occurrence in the Western Mediterranean is patent at the West Alboran Basin, where numerous MVs develop overlaying a major sedimentary depocenter containing overpressured shales. Although some of these MVs have been studied, the detailed biogeochemistry of expelled mud so far has not been examined in detail. This work provides the first results on the composition and origin of organic matter, Anaerobic Oxidation of Methane (AOM) processes and general characteristics on MV dynamics using lipid biomarkers as the main tool. Lipid biomarker analysis was performed on MV expelled material (mud breccias) and interbedded hemipelagic sediments from Perejil, Kalinin and Schneider's Heart MVs located in the northwest margin of the Alboran Sea. The n-alkane-distributions and n-alkane-derived indices (CPI and ACL), in combination with the epimerization degree of hopanes (22S/(22S + 22R)) indicate that all studied mud breccia have a similar biomarker composition consisting of mainly thermally immature organic matter with an admixture of petroleum-derived compounds. This concordant composition indicates that common source strata must feed all three studied MVs. The past or present AOM activity was established using lipid biomarkers specific for anaerobic methanotropic archaea (irregular isoprenoids and DGDs) and the depleted carbon isotope composition (δ13C) of crocetane/phytane. The presence of these lipid biomarkers, together with the low amounts of detected GDGTs, is consistent with the dominance of anaerobic methanotrophs of the ANME-2 over ANME-1, at least in mud breccia from Perejil MVs. In contrast, the scarce presence or lack of these AOM-related lipid biomarkers in sediments from Kalinin and Schneider's Heart MVs, suggest no recent active methane seepage has occurred at these sites. Moreover, the observed methane concentrations support the current activity of Perejil MV, and the very low methane seepage activity in Kalinin and Schneider's Heart MVs.

Surface properties of adipocyte lipid-binding protein: Response to lipid binding, and comparison with homologous proteins.

PubMed

LiCata, V J; Bernlohr, D A

1998-12-01

Adipocyte lipid-binding protein (ALBP) is one of a family of intracellular lipid-binding proteins (iLBPs) that bind fatty acids, retinoids, and other hydrophobic ligands. The different members of this family exhibit a highly conserved three-dimensional structure; and where structures have been determined both with (holo) and without (apo) bound lipid, observed conformational changes are extremely small (Banaszak, et al., 1994, Adv. Prot. Chem. 45, 89; Bernlohr, et al., 1997, Annu. Rev. Nutr. 17, 277). We have examined the electrostatic, hydrophobic, and water accessible surfaces of ALBP in the apo form and of holo forms with a variety of bound ligands. These calculations reveal a number of previously unrecognized changes between apo and holo ALBP, including: 1) an increase in the overall protein surface area when ligand binds, 2) expansion of the binding cavity when ligand is bound, 3) clustering of individual residue exposure increases in the area surrounding the proposed ligand entry portal, and 4) ligand-binding dependent variation in the topology of the electrostatic potential in the area surrounding the ligand entry portal. These focused analyses of the crystallographic structures thus reveal a number of subtle but consistent conformational and surface changes that might serve as markers for differential targeting of protein-lipid complexes within the cell. Most changes are consistent from ligand to ligand, however there are some ligand-specific changes. Comparable calculations with intestinal fatty-acid-binding protein and other vertebrate iLBPs show differences in the electrostatic topology, hydrophobic topology, and in localized changes in solvent exposure near the ligand entry portal. These results provide a basis toward understanding the functional and mechanistic differences among these highly structurally homologous proteins. Further, they suggest that iLBPs from different tissues exhibit one of two predominant end-state structural distributions of the ligand entry portal.

Patterns of organochlorine contamination in lake trout from Wisconsin waters of the Great Lakes

USGS Publications Warehouse

Miller, Michael A.; Madenjian, Charles P.; Masnado, Robert G.

1992-01-01

To investigate spatial and temporal patterns of organochlorine contamination in lake trout from Wisconsin waters of the Great Lakes, we examined laboratory contaminant analysis data of muscle tissue samples from Lake Michigan (n=317) and Lake Superior (n=53) fish. Concentrations of polychlorinated biphenyls (PCBs), chlordane, and dieldrin, reported as mg/kg wet weight in 620 mm to 640 mm mean length Lake Michigan lake trout, decreased over time. Mean total PCB concentration declined exponentially from 9.7 in 1975 to 1.9 in 1990. Total chlordane concentration declined 63 percent from 0.48 in 1983 to 0.18 in 1990, and dieldrin declined 52 percent during this same period, from 0.21 to 0.10. The bioaccumulation rate of PCBs is significantly lower for lake trout inhabiting Lake Michigan's midlake reef complex, compared to lake trout from the nearshore waters of western Lake Michigan. Organochlorine compound concentrations were greater in Lake Michigan lake trout than Lake Superior fish. Lake Superior lean lake trout and siscowet exhibited similar rates of PCB bioaccumulation despite major differneces in muscle tissue lipid content between the two subspecies. The lack of a significant difference in the PCB bioaccumulation rates of lean trout and siscowet suggests that lipid content may not be an important factor influencing PCB bioaccumulation in lake trout, within the range of lipid concentrations observed. Relative concentrations of the various organochlorine contaminants found in lake trout were highly correlated, suggesting similar mass balance processes for these compounds. Evidence presented revealing spatial and temporal patterns of organochlorine contamination may be of value in reestablishing self-sustaining populations of lake trout in Lake Michigan.

Brain metabolic pattern analysis using a magnetic resonance spectra classification software in experimental stroke.

PubMed

Jiménez-Xarrié, Elena; Davila, Myriam; Candiota, Ana Paula; Delgado-Mederos, Raquel; Ortega-Martorell, Sandra; Julià-Sapé, Margarida; Arús, Carles; Martí-Fàbregas, Joan

2017-01-13

Magnetic resonance spectroscopy (MRS) provides non-invasive information about the metabolic pattern of the brain parenchyma in vivo. The SpectraClassifier software performs MRS pattern-recognition by determining the spectral features (metabolites) which can be used objectively to classify spectra. Our aim was to develop an Infarct Evolution Classifier and a Brain Regions Classifier in a rat model of focal ischemic stroke using SpectraClassifier. A total of 164 single-voxel proton spectra obtained with a 7 Tesla magnet at an echo time of 12 ms from non-infarcted parenchyma, subventricular zones and infarcted parenchyma were analyzed with SpectraClassifier ( http://gabrmn.uab.es/?q=sc ). The spectra corresponded to Sprague-Dawley rats (healthy rats, n = 7) and stroke rats at day 1 post-stroke (acute phase, n = 6 rats) and at days 7 ± 1 post-stroke (subacute phase, n = 14). In the Infarct Evolution Classifier, spectral features contributed by lactate + mobile lipids (1.33 ppm), total creatine (3.05 ppm) and mobile lipids (0.85 ppm) distinguished among non-infarcted parenchyma (100% sensitivity and 100% specificity), acute phase of infarct (100% sensitivity and 95% specificity) and subacute phase of infarct (78% sensitivity and 100% specificity). In the Brain Regions Classifier, spectral features contributed by myoinositol (3.62 ppm) and total creatine (3.04/3.05 ppm) distinguished among infarcted parenchyma (100% sensitivity and 98% specificity), non-infarcted parenchyma (84% sensitivity and 84% specificity) and subventricular zones (76% sensitivity and 93% specificity). SpectraClassifier identified candidate biomarkers for infarct evolution (mobile lipids accumulation) and different brain regions (myoinositol content).

Effect of red yeast rice combined with antioxidants on lipid pattern, hs-CRP level, and endothelial function in moderately hypercholesterolemic subjects.

PubMed

Cicero, Arrigo F G; Morbini, Martino; Parini, Angelo; Urso, Riccardo; Rosticci, Martina; Grandi, Elisa; Borghi, Claudio

2016-01-01

Our aim was to test, through a crossover, double-blind, placebo-controlled randomized clinical trial, if a short-term treatment with 10 mg monacolins combined with antioxidants could improve lipid pattern, high-sensitivity C-reactive protein (hs-CRP), and endothelial function in a small cohort of moderately hypercholesterolemic subjects. Thus, 25 healthy, moderately hypercholesterolemic subjects were consecutively enrolled and, after 4 weeks of stabilization diet, were randomized to the sequence placebo followed by a washout, monacolins or monacolins followed by a washout, placebo, with each period being 4 weeks long. At each study step, a complete lipid pattern, safety parameters, hs-CRP, and endothelial function have been measured. When compared to the placebo phase, during monacolin treatment, patients experienced a more favorable percentage change in total cholesterol (TC) (TC after monacolin treatment, -18.35%; TC after placebo treatment, -5.39%), low-density lipoprotein cholesterol (LDL-C) (LDL after monacolin treatment, -22.36%; LDL after placebo treatment, -1.38%), non-high-density lipoprotein cholesterol (HDL-C) (non-HDL after monacolin treatment, -22.83%; non-HDL after placebo treatment: -7.15%), hs-CRP (hs-CRP after monacolin treatment: -2.33%; hs-CRP after placebo treatment, 2.11%), and endothelial function (pulse volume displacement after monacolin treatment, 18.59%; pulse volume displacement after placebo treatment, -6.69%). No significant difference was observed with regard to triglycerides, HDL-cholesterol, and safety parameters. On the basis of our data, we could demonstrate that a 10 mg monacolin nutraceutical treatment appears to safely reduce cholesterolemia, hs-CRP, and markers of vascular remodeling in moderately hypercholesterolemic subjects. These results need to be confirmed in larger patient samples and in studies with longer duration.

Cationic nanoparticles induce nanoscale disruption in living cell plasma membranes.

PubMed

Chen, Jiumei; Hessler, Jessica A; Putchakayala, Krishna; Panama, Brian K; Khan, Damian P; Hong, Seungpyo; Mullen, Douglas G; Dimaggio, Stassi C; Som, Abhigyan; Tew, Gregory N; Lopatin, Anatoli N; Baker, James R; Holl, Mark M Banaszak; Orr, Bradford G

2009-08-13

It has long been recognized that cationic nanoparticles induce cell membrane permeability. Recently, it has been found that cationic nanoparticles induce the formation and/or growth of nanoscale holes in supported lipid bilayers. In this paper, we show that noncytotoxic concentrations of cationic nanoparticles induce 30-2000 pA currents in 293A (human embryonic kidney) and KB (human epidermoid carcinoma) cells, consistent with a nanoscale defect such as a single hole or group of holes in the cell membrane ranging from 1 to 350 nm(2) in total area. Other forms of nanoscale defects, including the nanoparticle porating agents adsorbing onto or intercalating into the lipid bilayer, are also consistent; although the size of the defect must increase to account for any reduction in ion conduction, as compared to a water channel. An individual defect forming event takes 1-100 ms, while membrane resealing may occur over tens of seconds. Patch-clamp data provide direct evidence for the formation of nanoscale defects in living cell membranes. The cationic polymer data are compared and contrasted with patch-clamp data obtained for an amphiphilic phenylene ethynylene antimicrobial oligomer (AMO-3), a small molecule that is proposed to make well-defined 3.4 nm holes in lipid bilayers. Here, we observe data that are consistent with AMO-3 making approximately 3 nm holes in living cell membranes.

Long term betaine supplementation regulates genes involved in lipid and cholesterol metabolism of two muscles from an obese pig breed.

PubMed

Albuquerque, A; Neves, José A; Redondeiro, M; Laranjo, M; Félix, M R; Freitas, Amadeu; Tirapicos, José L; Martins, José M

2017-02-01

This study evaluates the effects of betaine supplementation (1gkg -1 for 20weeks) on the regulation of genes involved in lipid and cholesterol metabolism of Longissimus lumborum and Biceps femoris from obese Alentejano pigs. Betaine supplementation led to an increase in total cholesterol in both muscles, complementing results previously published indicating a significant increase on the intramuscular lipid content. The expression of twelve genes involved in lipogenesis, lipolysis/FA oxidation, FA transport, and cholesterol metabolism, as well as two transcription factors were also evaluated. Genes related to lipid and cholesterol synthesis plus FA transport were consistently up-regulated in both muscles of betaine fed pigs. On the other hand, genes related to lipolysis/FA oxidation were not affected or down-regulated by betaine supplementation. Our data suggest that the underlying mechanism regulating IMF and cholesterol accumulation in Alentejano pigs supplemented with betaine is associated with the up-regulation of genes involved in lipid synthesis, FA transport, and cholesterol synthesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Molecular Modeling of Lipid Membrane Curvature Induction by a Peptide: More than Simply Shape

PubMed Central

Sodt, Alexander J.; Pastor, Richard W.

2014-01-01

Molecular dynamics simulations of an amphipathic helix embedded in a lipid bilayer indicate that it will induce substantial positive curvature (e.g., a tube of diameter 20 nm at 16% surface coverage). The induction is twice that of a continuum model prediction that only considers the shape of the inclusion. The discrepancy is explained in terms of the additional presence of specific interactions described only by the molecular model. The conclusion that molecular shape alone is insufficient to quantitatively model curvature is supported by contrasting molecular and continuum models of lipids with large and small headgroups (choline and ethanolamine, respectively), and of the removal of a lipid tail (modeling a lyso-lipid). For the molecular model, curvature propensity is analyzed by computing the derivative of the free energy with respect to bending. The continuum model predicts that the inclusion will soften the bilayer near the headgroup region, an effect that may weaken curvature induction. The all-atom predictions are consistent with experimental observations of the degree of tubulation by amphipathic helices and variation of the free energy of binding to liposomes. PMID:24806928

Rupture and Spreading Dynamics of Lipid Membranes on a Solid Surface

NASA Astrophysics Data System (ADS)

Perazzo, Antonio; Shin, Sangwoo; Colosqui, Carlos; Young, Yuan-Nan; Stone, Howard A.

2017-11-01

The spreading of lipid membranes on solid surfaces is a dynamic phenomenon relevant to drug delivery, endocytosis, biofouling, and the synthesis of supported lipid bilayers. Current technological developments are limited by an incomplete understanding of the spreading and adhesion dynamics of a lipid bilayer under different physicochemical conditions. Here, we present recent experimental and theoretical results for the spreading of giant unilamellar vesicles (GUVs), where the vesicle shell consists of a lipid bilayer. In particular, we study the effect of different background ion concentrations, osmolarity mismatches between the interior and the exterior of the vesicles, and different surface chemistries of the glass substrate. In all of the studied cases, we observe a delay time before a GUV in contact with the solid surface eventually ruptures. The rupture kinetics and subsequent spreading dynamics is controlled by the ionic screening within the thin film of liquid between the vesicle and the surface. Different rupture mechanisms, mobilities of the spreading vesicle, and degrees of substrate coverage are observed by varying the electrolyte concentration, solid surface charge, and osmolarity mismatch.

Comparison of macro-gravimetric and micro-colorimetric lipid determination methods.

PubMed

Inouye, Laura S; Lotufo, Guiherme R

2006-10-15

In order to validate a method for lipid analysis of small tissue samples, the standard macro-gravimetric method of Bligh-Dyer (1959) [E.G. Bligh, W.J. Dyer, Can. J. Biochem. Physiol. 37 (1959) 911] and a modification of the micro-colorimetric assay developed by Van Handel (1985) [E. Van Handel, J. Am. Mosq. Control Assoc. 1 (1985) 302] were compared. No significant differences were observed for wet tissues of two species of fish. However, limited analysis of wet tissue of the amphipod, Leptocheirusplumulosus, indicated that the Bligh-Dyer gravimetric method generated higher lipid values, most likely due to the inclusion of non-lipid materials. Additionally, significant differences between the methods were observed with dry tissues, with the micro-colorimetric method consistently reporting calculated lipid values greater than as reported by the gravimetric method. This was most likely due to poor extraction of dry tissue in the standard Bligh-Dyer method, as no significant differences were found when analyzing a single composite extract. The data presented supports the conclusion that the micro-colorimetric method described in this paper is accurate, rapid, and minimizes time and solvent use.