Determination of the intravesicular ionized sodium concentration in a cell-free brain membrane vesicle preparation using the fluorescent indicator, SBFI

1992 ◽  
Vol 202 (2) ◽  
pp. 239-244 ◽  
Author(s):  
Laura C. Daniell
1978 ◽  
Vol 4 (5) ◽  
pp. 334-337 ◽  
Author(s):  
G. Horpacsy ◽  
J. Zinsmeyer ◽  
M. Mebel

Author(s):  
P Bijster ◽  
H L Vader ◽  
C L J Vink

We have shown that the sodium concentration in whole blood measured by direct potentiometry is higher than in plasma. The ‘erythrocyte-effect’, already described by Siggaard Andersen, is most pronounced for instruments equipped with a reference electrode with an open static liquid junction and is thus a general phenomenon. Instruments with a modified liquid junction show less interference. The same phenomenon appears for the determination of the potassium concentration, although the difference between whole blood and plasma, when measured with instruments equipped with a modified liquid junction, can be neglected in practice.


1998 ◽  
Vol 95 (16) ◽  
pp. 9256-9261 ◽  
Author(s):  
Anne Pierres ◽  
Hélène Feracci ◽  
Véronique Delmas ◽  
Anne-Marie Benoliel ◽  
Jean-Paul Thiery ◽  
...  

We describe a method allowing quantitative determination of the interaction range and association rate of individual surface-attached molecules. Spherical beads (1.4 μm radius) were coated with recombinant outer domains of the newly described classical type II cadherin 11, a cell adhesion molecule. Beads were driven along cadherin-coated surfaces with a hydrodynamic force of ≈1 pN, i.e., much less than the mechanical strength of many ligand-receptor bonds. Spheres displayed periods of slow motion interspersed with arrests of various duration. Particle position was monitored with 50 Hz frequency and 0.025 μm accuracy. Nearly 1 million positions were recorded and processed. Comparison between experimental and computer-simulated trajectories suggested that velocity fluctuations might be related quantitatively to Brownian motion perpendicular to the surface. The expected amplitude of this motion was of order of 100 nm. Theoretical analysis of the relationship between sphere acceleration and velocity allowed simultaneous determination of the wall shear rate and van der Waals attraction between spheres and surface. The Hamaker constant was estimated at 2.9 × 10−23 J. The frequency of bond formation was then determined as a function of sphere velocity. Experimental data were consistent with the view that the rate of association between a pair of adhesion molecules was ≈1.2 × 10−3 s−1 and the interaction range was ≈10 nm. It is concluded that the presented methodology allows sensitive measurement of sphere-to-surface interactions (with ≈10 fN sensitivity) as well as the effective range and rate of bond formation between individual adhesion molecules.


Lab on a Chip ◽  
2021 ◽  
Author(s):  
Hsiu-Yang Tseng ◽  
Chiu-Jen Chen ◽  
Zong-Lin Wu ◽  
Yong-Ming Ye ◽  
Guo-Zhen Huang

Cell-membrane permeability to water (Lp) and cryoprotective agents (Ps) of a cell type is a crucial cellular information for achieving optimal cryopreservation in the biobanking industry. In this work, a...


2020 ◽  
Vol 5 (6) ◽  
pp. 931-934
Author(s):  
Rayees Sheikh ◽  
Swapnil Hiremath ◽  
Edward G. Clark ◽  
Ayub Akbari ◽  
Christopher McCudden ◽  
...  

Author(s):  
M. V. Strizhkova ◽  
O. I. Sebezhko ◽  
T. V. Konovalova ◽  
K. N. Narozhnykh ◽  
V. A. Andreeva ◽  
...  

The study of the biological role of chemical elements in farm animals is one of the issues that scientists continue to investigate. A comprehensive study of the gene pool and phenofund of breeds and species of farm animals is being carried out in Siberia. An important issue is the search for vital markers of macronutrient accumulation, including sodium in organs and tissues of animals. The article presents data on the content of sodium in the blood serum of offspring obtained from bulls-producers of the Holstein breed. The experiment was carried out at OAO Vaganovo, Kemerovo region. The sodium concentration was determined by the atomic emission method on an ICP AES IRIS spectrometer at the V. S. Sobolev Analytical Center for Collective Use of the Institute of Geology and Mineralogy SB RAS. In the area of Holstein cattle breeding, there is no excess of LOC for heavy metals in soil, water, feed, organs and tissues of animals. The influence of the genotype of the fathers of the Holstein breed on the sodium content in the blood serum of sons was established. The sodium concentration in Fabio’s offspring was 1.9 times higher (240.4 mg/ l) than in Brio’s sons (P ˂ 0.001). By the level of sodium in the serum of offspring, bulls-producers were arranged in the following order: Brio ˂ Bonaire ˂ Malstrom ˂ Fabio in a proportion of 1: 1.3: 1.5: 1.9. The phenotypic variability of this element between the offspring of different producers differed by 3 times or more. Interbreed differentiation, the influence of the genotype of producers, differences between lines and families sign the hereditary determination of resistance and susceptibility to the accumulation of macro- and microelements in organs and tissues of animals.


2008 ◽  
Vol 67 (5) ◽  
pp. AB179 ◽  
Author(s):  
Kanwar R. Gill ◽  
Seth A. Gross ◽  
Linda R. Jones ◽  
Norris W. Preyer ◽  
Marquitta V. Scott ◽  
...  

2019 ◽  
Vol 116 (34) ◽  
pp. 17013-17022 ◽  
Author(s):  
Florence Caro ◽  
Nicole M. Place ◽  
John J. Mekalanos

Genes necessary for the survival or reproduction of a cell are an attractive class of antibiotic targets. Studying essential genes by classical genetics, however, is inherently problematic because it is impossible to knock them out. Here, we screened a set of predicted essential genes for growth inhibition using CRISPR-interference (CRISPRi) knockdown in the human pathogen Vibrio cholerae. We demonstrate that CRISPRi knockdown of 37 predicted essential genes inhibits V. cholerae viability, thus validating the products of these genes as potential drug target candidates. V. cholerae was particularly vulnerable to lethal inhibition of the system for lipoprotein transport (Lol), a central hub for directing lipoproteins from the inner to the outer membrane (OM), with many of these lipoproteins coordinating their own essential processes. Lol depletion makes cells prone to plasmolysis and elaborate membrane reorganization, during which the periplasm extrudes into a mega outer membrane vesicle or “MOMV” encased by OM which dynamically emerges specifically at plasmolysis sites. Our work identifies the Lol system as an ideal drug target, whose inhibition could deplete gram-negative bacteria of numerous proteins that reside in the periplasm.


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