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Lipid Particles (lipid + particle)
Selected AbstractsYeast Saccharomyces cerevisiae has two cis -prenyltransferases with different properties and localizations.GENES TO CELLS, Issue 6 2001Implication for their distinct physiological roles in dolichol synthesis Background Dolichol is a family of long-chain polyprenols, which is utilized as a sugar carrier in protein glycosylation in the endoplasmic reticulum (ER). We have identified a key enzyme of the dolichol synthesis, cis -prenyltransferase, as Rer2p from Saccharomyces cerevisiae. We have also isolated a multicopy suppressor of an rer2 mutant and named it SRT1. It encodes a protein similar to Rer2p but its function has not been established. Results The cis -prenyltransferase activity of Srt1p has been proved biochemically in the lysate of yeast cells lacking Rer2p. The polyprenol product of Srt1p is longer in chain length than that of Rer2p and is not sufficiently converted to dolichol and dolichyl phosphate, unlike that of Rer2p. The subcellular localization of these two isozymes has been examined by immunofluorescence microscopy and by the use of GFP fusion proteins. Whereas GFP-Rer2p is localized to the continuous ER and some dots associated with the ER, GFP-Srt1p shows only punctate localization patterns. Immunofluorescence double staining with Erg6p, a marker of lipid particles in yeast, indicates that Srt1p is mainly localized to lipid particles (lipid bodies). RER2 is mainly expressed in the early logarithmic phase, while the expression of SRT1 is induced in the stationary phase. Conclusions We have shown that yeast has two active cis -prenyltransferases with different properties. This result implies that the two isozymes have different physiological roles during the life cycle of the yeast. [source] Properties of cell penetrating peptides (CPPs)IUBMB LIFE, Issue 1 2006Alexandre Kerkis Abstract Different approaches have been developed for the introduction of macromolecules, proteins and DNA into target cells. Viral (retroviruses, lentiviruses, etc.) and nonviral (liposomes, bioballistics etc.) vectors as well as lipid particles have been tested as DNA delivery systems. However, all of them share several undesirable effects that are difficult to overcome, such as unwanted immunoresponse and limited cell targeting. The discovery of the cell penetrating peptides (CPPs) showing properties of macromolecules carriers and enhancers of viral vectors, opened new opportunities for the delivery of biologically active cargos, including therapeutically relevant genes into various cells and tissues. This review summarizes recent data about the best characterized CPPs as well as those sharing cell-penetrating and cargo delivery properties despite differing in the primary sequence. The putative mechanisms of CPPs penetration into cells and interaction with intracellular structures such as chromosomes, cytoskeleton and centrioles are addressed. We further discuss recent developments in overcoming the lack of cells specificity, one of the main obstacles for CPPs application in gene therapy. In particular, we review a newly discovered affinity of CPPs to actively proliferating cells. IUBMB Life, 58: 7 - 13, 2006 [source] Emulsion-Based Delivery Systems for Lipophilic Bioactive ComponentsJOURNAL OF FOOD SCIENCE, Issue 8 2007D.J. McClements ABSTRACT:, There is a pressing need for edible delivery systems to encapsulate, protect, and release bioactive lipids within the food, medical, and pharmaceutical industries. The fact that these delivery systems must be edible puts constraints on the type of ingredients and processing operations that can be used to create them. Emulsion technology is particularly suited for the design and fabrication of delivery systems for encapsulating bioactive lipids. This review provides a brief overview of the major bioactive lipids that need to be delivered within the food industry (for example, ,-3 fatty acids, carotenoids, and phytosterols), highlighting the main challenges to their current incorporation into foods. We then provide an overview of a number of emulsion-based technologies that could be used as edible delivery systems by the food and other industries, including conventional emulsions, multiple emulsions, multilayer emulsions, solid lipid particles, and filled hydrogel particles. Each of these delivery systems could be produced from food-grade (GRAS) ingredients (for example, lipids, proteins, polysaccharides, surfactants, and minerals) using simple processing operations (for example, mixing, homogenizing, and thermal processing). For each type of delivery system, we describe its structure, preparation, advantages, limitations, and potential applications. This knowledge can be used to facilitate the selection of the most appropriate emulsion-based delivery system for specific applications. [source] Axenic Culture of the Heterotrophic Dinoflagellate Pfiesteria shumwayae in a Semi-Defined MediumTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 1 2009HAYLEY M. SKELTON ABSTRACT. A semi-defined, biphasic culture medium was developed that supported the axenic growth of three strains of the heterotrophic dinoflagellate Pfiesteria shumwayae. Maximum cell yields and division rates in the semi-defined medium ranged from 0.1 × 105 to 4.0 × 105 cells/ml and 0.5 to 1.7 divisions/day, respectively, and depended on the concentration of the major components in the medium as well as the P. shumwayae strain. The medium contained high concentrations of certain dissolved and particulate organic compounds, including amino acids and lipids. Pfiesteria shumwayae flagellated cells were attracted to insoluble lipids present in the medium and appeared to feed on the lipid particles, suggesting that phagocytosis may be required for growth in axenic culture. Development of a semi-defined medium represents significant progress toward a completely defined axenic culture medium and subsequent determination of the biochemical requirements of P. shumwayae, needed to advance understanding of the nutritional ecology of this species. Further, this medium provides an economical, simplified method for generating high cell densities of P. shumwayae in axenic culture that will facilitate controlled investigations on the physiology and biochemistry of this heterotrophic dinoflagellate. [source] | ||||||||||