Nutrient transport in fish: Studies with membrane vesicles

1993 ◽  
pp. 139-158 ◽  
Author(s):  
C. Storelli ◽  
T. Verri
Keyword(s):  
Nutrient Transport ◽  
Membrane Vesicles

Development of nutrient transport systems in chick jejunum

1984 ◽  
Vol 246 (2) ◽  
pp. G101-G107 ◽  
Author(s):  
A. T. Shehata ◽  
J. Lerner ◽  
D. S. Miller
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Nutrient Transport ◽  
Membrane Vesicles ◽  
Developmental Time ◽  
Weight Basis ◽  
Transport Systems ◽  
Beta Alanine ◽  
Sodium Gradient ◽  
Wet Weight

Glutamate, beta-alanine, choline, and myoinositol transport was characterized in jejunal slices and brush-border membrane vesicles from 2- and 21-day chicks. Carrier-mediated, i.e., competitor-inhibitable, transport in slices (wet weight basis) and vesicles (protein basis) declined with age for the two amino acids but increased with age for myo-inositol; transport of choline did not change. These findings, along with previous data for the hexose system, cannot be explained solely by nonspecific changes in brush-border membrane architecture or permeability or by changes in the electrochemical sodium gradient that drives cotransport. They indicate that each specific brush-border membrane transport mechanism follows separate developmental time tables.

Dietary modulation of intestinal nutrient transport in the teleost fish tilapia

1991 ◽  
Vol 261 (6) ◽  
pp. R1568-R1574
Author(s):  
E. Titus ◽  
W. H. Karasov ◽  
G. A. Ahearn
Keyword(s):  
Brush Border Membrane ◽  
Fish Meal ◽  
Nutrient Transport ◽  
Membrane Vesicles ◽  
Oreochromis Mossambicus ◽  
Michaelis Constant ◽  
High Carbohydrate ◽  
Dietary Modulation ◽  
Carrier Mediated Transport ◽  
Low Carbohydrate

Tilapia (Oreochromis mossambicus) were fed a diet with either 60% carbohydrate (70% grain-4% fish meal) or 17% carbohydrate (11% grain-65% fish meal) for greater than or equal to 4 wk. Intestinal uptake of radiolabeled acetate, D-glucose, and L-proline was measured in brush-border membrane vesicles. As expected, fish fed high carbohydrate had significantly higher D-glucose uptake than those fed low carbohydrate [maximal uptake rate (Vmax), respectively, 84.2 +/- 18.2 vs. 37.4 +/- 10.9 pmol.mg protein-1.s-1; n = 4 batches of vesicles in each case; t test, P less than 0.025]. The change in glucose transport was specific, because in the same batches of vesicles there was no significant diet effect on carrier-mediated uptake of L-proline or acetate. Also as expected, dietary modulation of carrier-mediated transport was effected primarily by alterations in Vmax and not apparent Michaelis constant (Km); Km was not significantly altered by diet for either D-glucose (high carbohydrate vs. low carbohydrate, respectively, 0.34 +/- 0.17 vs. 0.12 +/- 0.03 mM; P greater than 0.2), L-proline (respectively, 0.10 +/- 0.03 vs. mM 0.13 +/- 0.05), or acetate (respectively, 4.8 +/- 1.4 vs. mM 6.5 +/- 2.2).

Nuclear Envelope Dynamics During Mitosis

1988 ◽  
Vol 46 ◽  
pp. 224-225
Author(s):  
Brian Burke
Keyword(s):  
Nuclear Envelope ◽  
Membrane Vesicles ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Animal Cells ◽  
Interphase Chromosome ◽  
Lamin B ◽  
Chromosome Architecture ◽  
Complex Membrane ◽  
Pore Complexes

The nuclear envelope is a complex membrane structure that forms the boundary of the nuclear compartment in eukaryotes. It regulates the passage of macromolecules between the two compartments and may be important for organizing interphase chromosome architecture. In interphase animal cells it forms a remarkably stable structure consisting of a double membrane ouerlying a protein meshwork or lamina and penetrated by nuclear pore complexes. The latter form the channels for nucleocytoplasmic exchange of macromolecules, At the onset of mitosis, however, it rapidly disassembles, the membranes fragment to yield small vesicles and the lamina, which is composed of predominantly three polypeptides, lamins R, B and C (MW approx. 74, 68 and 65 kDa respectiuely), breaks down. Lamins B and C are dispersed as monomers throughout the mitotic cytoplasm, while lamin B remains associated with the nuclear membrane vesicles.

Electrophysiological Characterization of Transport Across Outer Membrane Channels from Gram-Negative Bacteria in Their Native Environment

2019 ◽  
Author(s):  
Jiajun Wang ◽  
Rémi Terrasse ◽  
Jayesh Arun Bafna ◽  
Lorraine Benier ◽  
Mathias Winterhalter
Keyword(s):  
Outer Membrane ◽  
Lipid Membrane ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Multi Drug Resistance ◽  
Gram Negative Bacteria ◽  
Membrane Channels ◽  
Gram Negative ◽  
Electrophysiological Characterization

Multi-drug resistance in Gram-negative bacteria is often associated with low permeability of the outer membrane. To investigate the role of membrane channels in the uptake of antibiotics, we extract, purify and reconstitute them into artificial planar membranes. To avoid this time-consuming procedure, here we show a robust approach using fusion of native outer membrane vesicles (OMV) into planar lipid bilayer which moreover allows also to some extend the characterization of membrane protein channels in their native environment. Two major membrane channels from <i>Escherichia coli</i>, OmpF and OmpC, were overexpressed from the host and the corresponding OMVs were collected. Each OMV fusion revealed surprisingly single or only few channel activities. The asymmetry of the OMV´s translates after fusion into the lipid membrane with the LPS dominantly present at the side of OMV addition. Compared to conventional reconstitution methods, the channels fused from OMVs containing LPS have similar conductance but a much broader distribution. The addition of Enrofloxacin on the LPS side yields somewhat higher association (<i>k<sub>on</sub></i>) and lower dissociation (<i>k<sub>off</sub></i>) rates compared to LPS-free reconstitution. We conclude that using outer membrane vesicles is a fast and easy approach for functional and structural studies of membrane channels in the native membrane.

PLATELETS RELEASE MEMBRANE VESICLES CARRYING THE MATURE microRNA-221 AND ACTIVATED CASPASE-3 DURING THE PLATELET CONCENTRATE STORAGE

Tsitologiya ◽  
2018 ◽  
Vol 60 (7) ◽  
pp. 563-566
Author(s):  
V. V. Kishenko ◽  
◽  
K. A. Kondratov ◽  
V. Yu. Mikhailovskii ◽  
S. V. Sidorkevich ◽  
...  
Keyword(s):  
Caspase 3 ◽  
Membrane Vesicles ◽  
Platelet Concentrate ◽  
Mature Microrna
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