Uptake and intracellular transport pathways of fluorescent lipid analogues inAmoeba proteus (Rhizopoda: Amoebida)

PROTOPLASMA ◽  
1996 ◽  
Vol 193 (1-4) ◽  
pp. 91-104 ◽  
Author(s):  
P. -M. Topf ◽  
M. Theis ◽  
W. Stockem
Keyword(s):  
Intracellular Transport ◽  
Transport Pathways ◽  
Fluorescent Lipid Analogues ◽  
Fluorescent Lipid

scholarly journals Multivesicular Bodies as a Platform for Formation of the Marburg Virus Envelope

2004 ◽  
Vol 78 (22) ◽  
pp. 12277-12287 ◽  
Author(s):  
Larissa Kolesnikova ◽  
Beate Berghöfer ◽  
Sandra Bamberg ◽  
Stephan Becker
Keyword(s):  
Intracellular Transport ◽  
Matrix Protein ◽  
Lipid Membrane ◽  
Marburg Virus ◽  
Viral Envelope ◽  
Multivesicular Bodies ◽  
Virus Envelope ◽  
Transport Pathways ◽  
Virus Like Particles

ABSTRACT The Marburg virus (MARV) envelope consists of a lipid membrane and two major proteins, the matrix protein VP40 and the glycoprotein GP. Both proteins use different intracellular transport pathways: GP utilizes the exocytotic pathway, while VP40 is transported through the retrograde late endosomal pathway. It is currently unknown where the proteins combine to form the viral envelope. In the present study, we identified the intracellular site where the two major envelope proteins of MARV come together as peripheral multivesicular bodies (MVBs). Upon coexpression with VP40, GP is redistributed from the trans-Golgi network into the VP40-containing MVBs. Ultrastructural analysis of MVBs suggested that they provide the platform for the formation of membrane structures that bud as virus-like particles from the cell surface. The virus-like particles contain both VP40 and GP. Single expression of GP also resulted in the release of particles, which are round or pleomorphic. Single expression of VP40 led to the release of filamentous structures that closely resemble viral particles and contain traces of endosomal marker proteins. This finding indicated a central role of VP40 in the formation of the filamentous structure of MARV particles, which is similar to the role of the related Ebola virusVP40. In MARV-infected cells, VP40 and GP are colocalized in peripheral MVBs as well. Moreover, intracellular budding of progeny virions into MVBs was frequently detected. Taken together, these results demonstrate an intracellular intersection between GP and VP40 pathways and suggest a crucial role of the late endosomal compartment for the formation of the viral envelope.

3D Dynamic SERS Imaging of Intracellular Transport Pathways

2013 ◽  
Author(s):  
Kazuki Bando ◽  
Katsumasa Fujita ◽  
Nicholas Smith ◽  
Jun Ando ◽  
Satoshi Kawata
Keyword(s):  
Intracellular Transport ◽  
Transport Pathways ◽  
Sers Imaging

Ratiometric Fluorescent Mapping of pH and Glutathione Dictates Intracellular Transport Pathways of Micellar Nanoparticles

2020 ◽  
Vol 21 (8) ◽  
pp. 3436-3446
Author(s):  
Zexuan Ding ◽  
Guhuan Liu ◽  
Jinming Hu
Keyword(s):  
Intracellular Transport ◽  
Transport Pathways ◽  
Micellar Nanoparticles

scholarly journals Lipid recycling between the plasma membrane and intracellular compartments: transport and metabolism of fluorescent sphingomyelin analogues in cultured fibroblasts.

1989 ◽  
Vol 108 (6) ◽  
pp. 2169-2181 ◽  
Author(s):  
M Koval ◽  
R E Pagano
Keyword(s):  
Plasma Membrane ◽  
Intracellular Transport ◽  
Chinese Hamster ◽  
Membrane Lipid ◽  
Cell Periphery ◽  
Perinuclear Region ◽  
Cultured Fibroblasts ◽  
Plasma Membrane Lipid ◽  
Intracellular Compartments ◽  
Fluorescent Lipid

We examined the metabolism and intracellular transport of the D-erythro and L-threo stereoisomers of a fluorescent analogue of sphingomyelin, N-(N-[6-[(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino] caproyl])-sphingosylphosphorylcholine (C6-NBD-SM), in Chinese hamster ovary (CHO-K1) fibroblast monolayers. C6-NBD-SM was integrated into the plasma membrane bilayer by transfer of C6-NBD-SM monomers from liposomes to cells at 7 degrees C. The cells were washed, and within 10-15 min of being warmed to 37 degrees C, C6-NBD-SM was internalized from the plasma membrane to a perinuclear location that colocalized with the centriole and was distinct from the lysosomes and the Golgi apparatus. This perinuclear region was also labeled by internalized rhodamine-conjugated transferrin. C6-NBD-SM endocytosis was not inhibited when the microtubules were disrupted with nocodazole; rather, the fluorescent lipid was distributed in vesicles throughout the cell periphery instead of being internalized to the perinuclear region of the cell. The metabolism of C6-NBD-SM to other fluorescent sphingolipids at 37 degrees C and its effect on C6-NBD-SM transport was also examined. To study plasma membrane lipid recycling, C6-NBD-SM was first inserted into the plasma membrane of CHO-K1 cells and then allowed to be internalized by the cells at 37 degrees C. Any C6-NBD-SM remaining at the plasma membrane was then removed by incubation with nonfluorescent liposomes at 7 degrees C, leaving cells containing only internalized fluorescent lipid. The return of C6-NBD-SM to the plasma membrane from intracellular compartments upon further 37 degrees C incubation was then observed. The half-time for a complete round C6-NBD-SM recycling between the plasma membrane and intracellular compartments was approximately 40 min. Pretreatment of cells with either monensin or nocodazole did not inhibit C6-NBD-SM recycling.

scholarly journals Targeting toxins!: Drug delivery with poisons

2002 ◽  
Vol 24 (1) ◽  
pp. 18-20
Author(s):  
Lynne Roberts ◽  
Daniel Smith
Keyword(s):  
Escherichia Coli ◽  
Drug Delivery ◽  
Protein Synthesis ◽  
Castor Oil ◽  
Intracellular Transport ◽  
Shigella Dysenteriae ◽  
Lethal Effects ◽  
Transport Pathways ◽  
Pathogenic Escherichia Coli ◽  
Ricin A

Many organisms produce potently toxic proteins that act on other cells, sometimes with lethal effects. In this way, such proteins help to increase the chance of survival or proliferation of the producing organism. Moreover, a lot of toxins have an exquisitely specific action. For example, proteins studied in the Warwick toxin laboratory -- ricin, a toxin from the castor oil seed (Figure 1), and its relatives from the pathogenic Escherichia coli 0157 and the dysentery-causing bacterium (Shigella dysenteriae), have evolved to selectively target ribosomes within the cells of susceptible organisms, thereby enabling a fatal disruption of protein synthesis. What is very striking is the clever way these particular toxins exploit intracellular transport pathways to travel from the cell surface to their substrates in the cytosol. Once delivered there, each toxin molecule can disable approximately 2000 polysomes per minute, enough to eventually kill the cell. Research is now aimed at elucidating the molecular details of the cellular uptake of ricin and the Shiga family of toxins, and of exploiting their unusual trafficking properties for biotechnological purposes.

scholarly journals Evidence for the existence of lipid-diffusion barriers in the equatorial segment of human spermatozoa

1994 ◽  
Vol 304 (1) ◽  
pp. 211-218 ◽  
Author(s):  
E G J M Arts ◽  
S Jager ◽  
D Hoekstra
Keyword(s):  
Lateral Diffusion ◽  
Distribution Patterns ◽  
Human Spermatozoa ◽  
Membrane Domains ◽  
Prolonged Incubation ◽  
Bivalent Cations ◽  
Lipid Diffusion ◽  
The Stability ◽  
Fluorescent Lipid Analogues ◽  
Fluorescent Lipid

Liposomes consisting of negatively charged phospholipids interact almost exclusively with the equatorial segment (ES) of human spermatozoa provided the cells have undergone the acrosome reaction (AR) [Arts, Kuiken, Jager and Hoekstra (1993) Eur. J. Biochem. 217, 1001-1009]. Using fluorescently tagged liposomes, this interaction can be observed by fluorescence microscopy, showing either a diffuse fluorescence in the ES region (pattern ESd, presumably reflecting membrane-incorporated lipids as a result of fusion) or a punctate fluorescence (pattern ESp, representing adhering liposomes). These distribution patterns remain unchanged during prolonged incubation, up to 40 min. Not only do these observations suggest the existence of fairly specific liposomal binding sites, associated with the ES region, but also that a barrier to lipid lateral diffusion seems to exist in the ES membrane. Using liposomes that contain fluorescent lipid analogues in either both leaflets or in the inner leaflet only, we demonstrate that this putative barrier entails both membrane leaflets. Treatment with EDTA caused fluorescence to spread from the ES towards other membrane domains. Since only spermatozoa displaying pattern ESd were affected by the chelator, the randomization was not caused by EDTA-induced fusion activity. Therefore, this observation provides further evidence that in spermatozoa displaying pattern ESd the fluorescent lipid analogues were incorporated in the ES membrane as a result of fusion. Furthermore, these experiments support the view of the existence of a transmembranous block to lipid lateral diffusion in the ES, the stability of which may be governed by bivalent cations.

Application of Stochastic Network Models for the Study of Molecular Transport Processes in Bone

2004 ◽  
Author(s):  
Roland Steck ◽  
Melissa L. Knothe Tate
Keyword(s):  
Cortical Bone ◽  
Intracellular Transport ◽  
Histological Study ◽  
Bone Matrix ◽  
Molecular Transport ◽  
Bone Diseases ◽  
Transport Processes ◽  
Transport Pathways ◽  
Tissue Samples ◽  
Waste Products

Osteocytes are the most abundant cells in bone. They are entombed in lacunae within the bone matrix, but are interconnected via their processes that run within the canaliculi with other osteocytes, as well as with the osteoblasts and bone lining cells on the bone surfaces, and thus from a cellular syncytium. However, the osteocytes are not immediately connected with the vasculature of bone, which means that the transport of nutrients and hormones to the cells and the removal of waste products from the cells, as well as transport of signaling molecules between the cells, has to occur either via the pericellular fluid spaces in the lacunocanalicular network, via the matrix micropores between the collagen fibers and the apatite crystals, or via intracellular transport mechanisms. Only recently our laboratory and other research groups have started to examine the transport pathways of different molecular size substances within bone systematically, using experimental tracer methods (e.g. [1, 7]). These experiments have unveiled the molecular sieving characteristics of bone: While small tracers with molecular weights of 300 Daltons (Da, e.g. glucose and small amino acids) are found in abundance throughout the bone matrix and the lacunocanalicular network, larger molecules (e.g. cytokines and serum derived proteins) are only transported through the pericellular spaces of the lacunocanalicular network. Furthermore, the transport of these substances through the lacunocanalicular network can be enhanced by mechanical loading of bone [1]. These findings highlight the importance of the lacunocanalicular network for the survival of the osteocytes and thereby tissue health. However, the state of the osteocyte syncytium is affected by age and bone diseases. It has been shown that the number of osteocytes in cortical bone decreases with age [6]. Furthermore, a histological study of cortical bone tissue samples from donors undergoing hip replacement surgery has shown that the morphology of the lacunocanalicular network is altered in diseased bone [2].

Two-Photon Ratiometric Fluorescent Mapping of Intracellular Transport Pathways of pH-Responsive Block Copolymer Micellar Nanocarriers

2013 ◽  
Vol 2 (12) ◽  
pp. 1576-1581 ◽  
Author(s):  
Tao Liu ◽  
Jinming Hu ◽  
Zhenyu Jin ◽  
Fan Jin ◽  
Shiyong Liu
Keyword(s):  
Block Copolymer ◽  
Intracellular Transport ◽  
Ph Responsive ◽  
Transport Pathways ◽  
Two Photon

Intracellular transport of phosphatidic acid and phosphatidylcholine into lipid bodies: use of fluorescent lipids to study lipid-body formation in an oleaginous fungus

2000 ◽  
Vol 28 (6) ◽  
pp. 723-725
Author(s):  
Y. Kamisaka ◽  
N. Noda
Keyword(s):  
Phosphatidic Acid ◽  
Temperature Dependence ◽  
Intracellular Transport ◽  
Lipid Body ◽  
Lipid Transport ◽  
Lipid Bodies ◽  
Transport Pathways ◽  
Body Formation ◽  
Oleaginous Fungus ◽  
Fluorescent Lipids

Fluorescent phosphatidic acid and phosphatidylcholine were used to characterize lipid-transport pathways into lipid bodies in an oleaginous fungus, Mortierella ramanniana var. angulispora. Several characteristics of the lipid transport such as temperature dependence and ATP dependence were evaluated. The transport depicted by these fluorescent lipids was consistent with metabolism of radiolabelled lipids, indicating that fluorescent lipids are useful to study lipid-body formation in this fungus. The results dissect lipid transport of phosphatidic acid and phosphatidylcholine into lipid bodies and reveal regulatory steps for lipidbody formation in this fungus.

Sign in / Sign up

Export Citation Format

Share Document