Organelles lipid droplets

Fig. 6 TEM micrographs of seed coat and aleurone cells of radish control seed 18 h after sowing in water e, epidermis pi, pigment layer al, aleurone layer. (A) Bar = 30 pm Particulars of the aleurone cell showing some organelles nucleus (n), plasmodesmata (pd), protein bodies (pb) and lipid droplets (Id). (B, C). Bar = 5 mm. 

Vibrational imaging of living cells has been applied for studying intracellular lipid droplet organelles [86, 89, 90, 113, 114] (cf. Fig. 6.10A), monitoring receptor-mediated endocytosis [92], analyzing mouse embryonic stem cells... 

Fig. 6.10. In vivo multiplex CARS microspectroscopy of a NIH 3T3-L1 fibroblast cell in the high-wavenumber region where C-H stretch vibrations reside. A CARS image revealing the intracellular distribution of constituents with high densities of lipids, such as the membrane envelope of the nucleus and intracellular lipid droplet (LD) organelles. Typical MEM-reconstructed Raman spectra taken for (B) a single LD organelle that is indicated by the arrow in A, (C) the nucleus, and (D) the cytoplasm. The spectrum exposure time was 0.3 s...

Martin S, Parton RG. Lipid droplets a unified view of a dynamic organelle. Nat. Rev. Mol. Cell Biol. 2006 7 373-378. 

Illustrated are the concentration of UC and CE within each organelle and the percentage of UC and CE within each organelle relative to the total amount of UC and CE within the cell. Column 2 values should be viewed cautiously, as there is some question of the amount of contamination of cellular fractions by plasma membrane [3], an organelle containing the largest amount of UC within the cell. Thus, plasma membrane UC may be much closer to 80% and other organelle UC much lower than indicated here. Column 4 reflects the virtual insolubility of CE within phospholipid membranes [4,5], and that most cellular CE appears to be contained within lipid droplets. Column 5 shows an apparent selective accumulation of UC within plasma membrane and mitochondria, and of CE within lipid droplets... 

Beckman, M. Great Balls of Fat. Sdence 311, 1232-1234 (2006). [An article about lipid droplets and their organelle nature.]... 

A diagram of a section through a typical yeast cell is shown in Fig. 16.2. The cell is bounded by a wall which may bear one or several scars, and within the wall lies the cell membrane. Connected with the membrane and extending into the cytoplasm is the endoplasmic reticulum. This membranous system also appears to connect with the nuclear membrane which forms the boundary of the nucleus. Other organelles within the cytoplasm are the mitochondria and vacuoles, the latter often containing granular material. Lipid droplets may also be found in the cytoplasm. 

Cellular organelles, mitochondria and pro-plastids, kept their normal structure in adapted cells at values of low water potential (approx. -2.0 MPa) which caused membrane disruption and appearance of lipid droplets when this intensity of stress was applied to unadapted cells (Fig. 2). Therefore, a gradual adaptation to low water potential allowed the conservation of a particular state of membrane structure, which is critical for a wide spectrum of membrane-associated protein functions. 

Fig. 1. Section of choline-deficient rat liver, labeled by incubation with choline-The radioautographic reaction, which represents labeled lecithin is seen over cellular organelles, but not over the bulk of the lipid droplets. X 9000 (From O. Stein and Stein, 1969, reproduced by permission of the Editor of J. Cell Biol.)... 

Another finding revealed by radioautography was the accumulation of label over lipid droplets with time of perfusion (Fig. 4), which indicated that the triglyceride deposited in droplet form has a turnover rate slower than that located in the intracellular organelles. 

Lipid droplets (LDs) are organelles for the storage of neutral lipids in cells. Excessive lipid storage led to the pathogenesis of obesity, diabetes, and atherosclerosis. 

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