Correction for 'Fluid displacement during droplet formation at microfluidic flow-focusing junctions' by Haishui Huang
et al., Lab Chip
, 2015,
15
, 4197-4205.
Lipid droplets (LDs) are multi-functional organelles consisting of a neutral lipid core surrounded by a phospholipid monolayer, and exist in organisms ranging from bacteria to humans. Here we study ...the functions of LDs in the oleaginous bacterium Rhodococcus jostii. We show that these LDs bind to genomic DNA through the major LD protein, MLDS, which increases survival rate of the bacterial cells under nutritional and genotoxic stress. MLDS expression is regulated by a transcriptional regulator, MLDSR, that binds to the operator and promoter of the operon encoding both proteins. LDs sequester MLDSR, controlling its availability for transcriptional regulation. Our findings support the idea that bacterial LDs can regulate nucleic acid function and facilitate bacterial survival under stress.
Surface modification by grafting polymers on solid materials is an important strategy used to improve surface properties. This article reports that under appropriate conditions, very thin layers with ...desired morphologies may be constructed on a plasma-treated substrate by feeding a small quantity of a monomer with a mist stream carrying droplets produced from monomer solutions. We investigate the effects of process parameters that affect layer morphology, including exposure time to the mist stream, concentration of the monomer solution, and solvent selectivity. For a methyl methacrylate solution in ethanol, nanoparticles are uniformly grown with increasing monomer concentration or exposure time and finally form a porous layer at 3.65 mol L super(-1) for 30 min. Decreasing solvent polarity not only affects surface morphology, but also increases hydrophobicity of the resulting surface. With 2,2,3,4,4,4-hexafluorobutyl methacrylate as the monomer, SEM and AFM micrographs indicated that mist polymerization results in numerous microspheres on the activated surface. These experimental results were interpreted by a mechanism in terms of an in situpolymerization accompanied by a phase transformation of the resulting polymer. Specifically, plasma treatment provides highly active cations and radicals to initiate very rapid polymerization, and the resulting polymers are consequently deposited from the liquid onto the surface under phase transition mechanisms.
Lipid droplets were long considered to be simple storage structures, but they have recently been shown to be dynamic organelles involved in diverse biological processes, including emerging roles in ...innate immunity. Various intracellular pathogens, including viruses, bacteria, and parasites, specifically target host lipid droplets during their life cycle. Viruses such as hepatitis C, dengue, and rotaviruses use lipid droplets as platforms for assembly. Bacteria, such as mycobacteria and Chlamydia, and parasites, such as trypanosomes, use host lipid droplets for nutritional purposes. The possible use of lipid droplets by intracellular pathogens, as part of an anti‐immunity strategy, is an intriguing question meriting further investigation in the near future.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
A novel microextraction technique, air-assisted liquid-liquid microextraction (AALLME), which is a new version of dispersive liquid-liquid microextraction (DLLME) method has been developed for ...extraction and preconcentration of phthalate esters, dimethyl phthalate (DMP), diethyl phthalate (DEP), di-iso-butyl phthalate (DIBP), di-n-butyl phthalate (DNBP), and di-2-ethylhexyl phthalate (DEHP), from aqueous samples prior to gas chromatographyaflame ionization detection (GCaFID) analysis. In this method, much less volume of an organic solvent is used as extraction solvent in the absence of a disperser solvent. Fine organic droplets were formed by sucking and injecting of the mixture of aqueous sample solution and extraction solvent with a syringe for several times in a conical test tube. After extraction, phase separation was performed by centrifugation and the enriched analytes in the sedimented phase were determined by GCaFID. Under the optimum extraction conditions, the method showed low limits of detection and quantification between 0.12a1.15 and 0.85a4 ng mLa1, respectively. Enrichment factors (EFs) and extraction recoveries (ERs) were in the ranges of 889a1022 and 89a102%, respectively. The relative standard deviations (RSDs) for the extraction of 100 ng mLa1 and 500 ng mLa1 of each phthalate ester were less than 4% for intra-day (n = 6) and inter-days (n = 4) precision. Finally some aqueous samples were successfully analyzed using the proposed method and three analytes, DIBP, DNBP and DEHP, were determined in them at ng mLa1 level.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Lithium titanate (Li(2)TiO(3)) is an important tritium breeder for fusion blanket concepts. In the present study, Li(2)TiO(3) ceramic pebbles were successfully fabricated by a graphite bed process. ...In this process, graphite bed which had been engraved with spherical pits acted as a casting mould. Droplets of Li(2)TiO(3) suspensions were dispersed into the spherical pits to form pebbles due to the hydrophobic nature of the graphite powder. After drying, green pebbles were sieved and sintered to produce Li(2)TiO(3) pebbles. The fabrication process and properties of the pebbles have been investigated. The experimental results showed that the sphericity of Li(2)TiO(3) pebbles was influenced by solid/liquid ratio and diameter. XRD results demonstrated that Li(2)TiO(3) pebbles with high purity have been prepared by the graphite bed process. SEM revealed that the pebbles have uniform microstructure and adequate open porosity. The Li(2)TiO(3) pebbles sintered at 1150 degree C have optimal properties, such as high density (about 90% TD) and high crush load (about 40 N).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We investigate the effect of turbulence on the collisional growth of micrometer-sized droplets through high-resolution numerical simulations with well-resolved Kolmogorov scales, assuming a collision ...and coalescence efficiency of unity. The droplet dynamics and collisions are approximated using a superparticle approach. In the absence of gravity, we show that the time evolution of the shape of the droplet-size distribution due to turbulence-induced collisions depends strongly on the turbulent energy-dissipation rate Formula: see text, but only weakly on the Reynolds number. This can be explained through the Formula: see text dependence of the mean collision rate described by the Saffman–Turner collision model. Consistent with the Saffman–Turner collision model and its extensions, the collision rate increases as Formula: see text even when coalescence is invoked. The size distribution exhibits power-law behavior with a slope of −3.7 from a maximum at approximately 10 up to about 40 μm. When gravity is invoked, turbulence is found to dominate the time evolution of an initially monodisperse droplet distribution at early times. At later times, however, gravity takes over and dominates the collisional growth. We find that the formation of large droplets is very sensitive to the turbulent energy dissipation rate. This is because turbulence enhances the collisional growth between similar-sized droplets at the early stage of raindrop formation. The mean collision rate grows exponentially, which is consistent with the theoretical prediction of the continuous collisional growth even when turbulence-generated collisions are invoked. This consistency only reflects the mean effect of turbulence on collisional growth.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Dynamics and functions of lipid droplets Olzmann, James A; Carvalho, Pedro
Nature reviews. Molecular cell biology,
03/2019, Volume:
20, Issue:
3
Journal Article
Peer reviewed
Open access
Lipid droplets are storage organelles at the centre of lipid and energy homeostasis. They have a unique architecture consisting of a hydrophobic core of neutral lipids, which is enclosed by a ...phospholipid monolayer that is decorated by a specific set of proteins. Originating from the endoplasmic reticulum, lipid droplets can associate with most other cellular organelles through membrane contact sites. It is becoming apparent that these contacts between lipid droplets and other organelles are highly dynamic and coupled to the cycles of lipid droplet expansion and shrinkage. Importantly, lipid droplet biogenesis and degradation, as well as their interactions with other organelles, are tightly coupled to cellular metabolism and are critical to buffer the levels of toxic lipid species. Thus, lipid droplets facilitate the coordination and communication between different organelles and act as vital hubs of cellular metabolism.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Fatty liver disease (FLD) is a disorder in which accumulation of triglycerides (TGs) in the liver can lead to inflammation, fibrosis, and cirrhosis. Previously, we identified a variant (I148M) in ...patatin-like phospholipase domain-containing protein 3 (PNPLA3) that is strongly associated with FLD, but the mechanistic basis for the association remains elusive. Although PNPLA3 has TG hydrolase activity in vitro, inactivation or overexpression of the WT protein in mice does not cause steatosis. In contrast, expression of two catalytically defective forms of PNPLA3 (I148M or S47A) in sucrose-fed mice causes accumulation of both PNPLA3 and TGs on hepatic lipid droplets (LDs). To determine if amassing PNPLA3 on LDs is a cause or consequence of steatosis, we engineered a synthetic isoform of PNPLA3 that uncouples protein accumulation from loss of enzymatic activity. Expression of a ubiquitylation-resistant form of PNPLA3 in mice caused accumulation of PNPLA3 on hepatic LDs and development of FLD. Lowering PNPLA3 levels by either shRNA knockdown or proteolysis-targeting chimera (PROTAC)-mediated degradation reduced liver TG content in mice overexpressing PNPLA3(148M). Taken together, our results show that the steatosis associated with PNPLA3(148M) is caused by accumulation of PNPLA3 on LDs.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Abstract One of the most important metabolic hallmarks of cancer cells is deregulation of lipid metabolism. In addition, enhancing de novo fatty acid (FA) synthesis, increasing lipid uptake and ...lipolysis have also been considered as means of FA acquisition in cancer cells. FAs are involved in various aspects of tumourigenesis and tumour progression. Therefore, targeting lipid metabolism is a promising therapeutic strategy for human cancer. Recent studies have shown that reprogramming lipid metabolism plays important roles in providing energy, macromolecules for membrane synthesis, and lipid signals during cancer progression. Moreover, accumulation of lipid droplets in cancer cells acts as a pivotal adaptive response to harmful conditions. Here, we provide a brief review of the crucial roles of FA metabolism in cancer development, and place emphasis on FA origin, utilization and storage in cancer cells. Understanding the regulation of lipid metabolism in cancer cells has important implications for exploring a new therapeutic strategy for management and treatment of cancer.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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