scholarly journals The effect of glass-forming sugars on vesicle morphology and water distribution during drying

2014 ◽  
Vol 11 (99) ◽  
pp. 20140646 ◽  
Author(s):  
C. J. Vogl ◽  
M. J. Miksis ◽  
S. H. Davis ◽  
D. Salac
Keyword(s):  
Water Distribution ◽  
Concentration Field ◽  
Lipid Vesicle ◽  
Glass Forming ◽  
A Cell ◽  
Potential Alternative ◽  
High Concentrations ◽  
Water Trapping ◽  
Membrane Deformations ◽  
Spatially Varying

Cryopreservation requires that stored materials be kept at extremely low temperatures and uses cryoprotectants that are toxic to cells at high concentrations. Lyopreservation is a potential alternative where stored materials can remain at room temperatures. That storage process involves desiccating cells filled with special glass-forming sugars. However, current desiccation techniques fail to produce viable cells, and researchers suspect that incomplete vitrification of the cells is to blame. To explore this hypothesis, a cell is modelled as a lipid vesicle to monitor the water content and membrane deformation during desiccation. The vesicle is represented as a moving, bending-resistant, inextensible interface and is tracked by a level set method. The vesicle is placed in a fluid containing a spatially varying sugar concentration field. The glass-forming nature is modelled through a concentration-dependent diffusivity and viscosity. It is found that there are optimal regimes for the values of the osmotic flow parameter and of the concentration dependence of the diffusivity to limit water trapping in the vesicle. Furthermore, it is found that the concentration dependencies of the diffusivity and viscosity can have profound effects on membrane deformations, which may have significant implications for vesicle damage during the desiccation process.

Effect of Boron on the Groundwater Quality in Altai Region

2021 ◽  
pp. 42-48
Author(s):  
Gennady Ya. Baryshnikov ◽  
Svetlana S. Slazhneva ◽  
Nina B. Maximovа ◽  
Petr V. Sotnikov
Keyword(s):  
Groundwater Quality ◽  
Water Distribution ◽  
Maximum Permissible Concentration ◽  
Human Consumption ◽  
Altai Region ◽  
High Incidence ◽  
General Complex ◽  
High Concentrations ◽  
The Relationship

Boron (В) is widely spread in surface and ground waters. The article deals with the problem of drinking groundwater quality. Groundwater is the only source of water supply, in the most districts of the Altai Region. This suggests that the quality of groundwater is of great importance for the population of the region. Drinking water should be suitable for human consumption and for all household purposes. The main attention is focused on identifying the area of distribution B containing waters with the content exceeding the maximum permissible concentration (MPC). The relationship between В and dry residue (MCO) is analyzed. Crucial factors responsible for high В concentration have been identified. The general complex research of presence, distribution and sources of В inflow into groundwaters of the Altai Region are defined in the article. The relationship between the В content and the high incidence of people living in areas with a high В content has been revealed. It was found that high concentrations of В (more than 0.5 mg/l) correspond to the zone of brackish water distribution, which occupies almost the entire territory of the steppe Altai - Kulundinsko-Barnaul artesian basin. Their distribution coincides geographically with the distribution of В.

scholarly journals 2P282 Photo-induced reversible transformation in a cell-sized lipid vesicle(Native and artificial biomembranes,Poster Presentations)

2007 ◽  
Vol 47 (supplement) ◽  
pp. S183
Author(s):  
Ken-ichi Ishii ◽  
Tsutomu Hamada ◽  
Takeshi Nagasaki ◽  
Masahiro Takagi
Keyword(s):  
Lipid Vesicle ◽  
Reversible Transformation ◽  
A Cell ◽  
Poster Presentations

scholarly journals CB1 Receptor-Dependent and Independent Induction of Lipolysis in Primary Rat Adipocytes by the Inverse Agonist Rimonabant (SR141716A)

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 896 ◽  
Author(s):  
Günter A. Müller ◽  
Andreas W. Herling ◽  
Susanne Wied ◽  
Timo D. Müller
Keyword(s):  
Cannabinoid Receptor ◽  
Inverse Agonist ◽  
Hormone Sensitive Lipase ◽  
Acute Administration ◽  
Free System ◽  
Peripheral Tissues ◽  
Rat Adipocytes ◽  
A Cell ◽  
High Concentrations ◽  
Stimulation Of

(1) Background: Acute administration of the cannabinoid receptor 1 (CB1R) inverse agonist Rimonabant (SR141716A) to fed Wistar rats was shown to elicit a rapid and short-lasting elevation of serum free fatty acids. (2) Methods: The effect of Rimonabant on lipolysis in isolated primary rat adipocytes was studied to raise the possibility for direct mechanisms not involving the (hypothalamic) CB1R. (3) Results: Incubation of these cells with Rimonabant-stimulated lipolysis to up to 25% of the maximal isoproterenol effect, which was based on both CB1R-dependent and independent mechanisms. The CB1R-dependent one was already effective at Rimonabant concentrations of less than 1 µM and after short-term incubation, partially additive to β-adrenergic agonists and blocked by insulin and, in part, by adenosine deaminase, but not by propranolol. It was accompanied by protein kinase A (PKA)-mediated association of hormone-sensitive lipase (HSL) with lipid droplets (LD) and dissociation of perilipin-1 from LD. The CB1R-independent stimulation of lipolysis was observed only at Rimonabant concentrations above 1 µM and after long-term incubation and was not affected by insulin. It was recapitulated by a cell-free system reconstituted with rat adipocyte LD and HSL. Rimonabant-induced cell-free lipolysis was not affected by PKA-mediated phosphorylation of LD and HSL, but abrogated by phospholipase digestion or emulsification of the LD. Furthermore, LD isolated from adipocytes and then treated with Rimonabant (>1 µM) were more efficient substrates for exogenously added HSL compared to control LD. The CB1R-independent lipolysis was also demonstrated in primary adipocytes from fed rats which had been treated with a single dose of Rimonabant (30 mg/kg). (4) Conclusions: These data argue for interaction of Rimonabant (at high concentrations) with both the LD surface and the CB1R of primary rat adipocytes, each leading to increased access of HSL to LD in phosphorylation-independent and dependent fashion, respectively. Both mechanisms may lead to direct and acute stimulation of lipolysis at peripheral tissues upon Rimonabant administration and represent targets for future obesity therapy which do not encompass the hypothalamic CB1R.

The effect of intracellular geometry on auxin transport. I. Centrifugation experiments

1981 ◽  
Vol 214 (1194) ◽  
pp. 53-67 ◽  
Keyword(s):  
Thin Layer ◽  
High Velocity ◽  
Plant Hormone ◽  
Auxin Transport ◽  
The Other ◽  
Permeability Barrier ◽  
Cell Geometry ◽  
Internal Cell ◽  
A Cell ◽  
High Concentrations

When coleoptiles are centrifuged, the velocity of transport of the plant hormone auxin is dramatically altered. I show here that this may be due to changes in internal cell geometry. The tonoplast, the membrane surrounding the vacuole, may present a substantial permeability barrier for the diffusion of auxin. After centrifugation, the cytoplasm sediments to one end of the cell, displacing the vacuole to the other. If auxin, on entering the cell, must first accumulate in a mass of cytoplasm before crossing the tonoplast, the velocity will be lowered. If, on the other hand, there is only a thin layer of cytoplasm where auxin enters, high concentrations will quickly build up and enable auxin to cross the tonoplast, giving a high velocity. This would explain why centrifugation in a basal direction increases velocity, while apical centrifugation de­creases it. If this explanation is correct, and if the tonoplast constitutes an appreciable permeability barrier, then the position of the vacuole may strongly influence the flux of auxin inside a cell. I show in the adjoining paper that this can explain the changed transport pattern seen during the geotropic response.

Characteristics of a novel, anaerobic, mycoplasma-like bacterium from Ace Lake, Antarctica

1992 ◽  
Vol 4 (2) ◽  
pp. 155-162 ◽  
Author(s):  
P.D. Franzmann ◽  
M. Rohde
Keyword(s):  
Anaerobic Bacterium ◽  
Anaerobic Bacteria ◽  
Taxonomic Status ◽  
Optimum Temperature ◽  
Obligately Anaerobic ◽  
A Cell ◽  
Large Genome Size ◽  
High Concentrations ◽  
Pass Through

An obligately anaerobic bacterium that lacked a cell wall was isolated from the hypolimnion of Ace Lake, Antarctica. Cells were very pleomorphic, forming cocci, filaments up to 25 μm in length, and annular shapes. The organism was morphologically very similar to some members of the class Mollicutes which contains two genera of obligately anaerobic bacteria, Anaeroplasma and Asteroleplasma. Like members of the class, the isolate was resistant to high concentrations of penicillin (1000 Units ml-1). Similar to Anaeroplasma, the organism had a low DNA G+C content (29.3±0.4) and produced hydrogen, carbon dioxide, acetic acid, lactic acid and succinic acid from the fermentation of glucose. However, the taxonomic status of the strain remained unclear as, unlike members of the class Mollicutes, the isolate had a relatively large genome size (2.26±0.11 × 109 daltons), did not pass through 0.45 μm pore size filters, and did not form typical mycoplasma-like colonies. The organism was psychrophilic with an optimum temperature for growth between 12°C and 13°C. A phenotypic description of the organism is given and the ecological role of the organism is inferred from its phenotype and the characteristics of its Antarctic habitat.

scholarly journals High-Level β-Lactam Resistance and Cell Wall Synthesis Catalyzed by the mecA Homologue of Staphylococcus sciuri Introduced into Staphylococcus aureus

2005 ◽  
Vol 187 (19) ◽  
pp. 6651-6658 ◽  
Author(s):  
Anatoly Severin ◽  
Shang Wei Wu ◽  
Keiko Tabei ◽  
Alexander Tomasz
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
High Performance ◽  
Protein Product ◽  
Spectrometric Analysis ◽  
Cell Wall Synthesis ◽  
Absolute Dependence ◽  
A Cell ◽  
High Concentrations ◽  
High Level

ABSTRACT A close homologue of mecA, the determinant of broad-spectrum β-lactam resistance in Staphylococcus aureus was recently identified as a native gene in the animal commensal species Staphylococcus sciuri. Introduction of the mecA homologue from a methicillin-resistant strain of S. sciuri into a susceptible strain of S. aureus caused an increase in drug resistance and allowed continued growth and cell wall synthesis of the bacteria in the presence of high concentrations of antibiotic. We determined the muropeptide composition of the S. sciuri cell wall by using a combination of high-performance liquid chromatography, mass spectrometric analysis, and Edman degradation. Several major differences between the cell walls of S. aureus and S. sciuri were noted. The pentapeptide branches in S. sciuri were composed of one alanine and four glycine residues in contrast to the pentaglycine units in S. aureus. The S. sciuri wall but not the wall of S. aureus contained tri- and tetrapeptide units, suggesting the presence of dd- and ld-carboxypeptidase activity. Most interestingly, S. aureus carrying the S. sciuri mecA and growing in methicillin-containing medium produced a cell wall typical of S. aureus and not S. sciuri, in spite of the fact that wall synthesis under these conditions had an absolute dependence on the heterologous S. sciuri gene product. The protein product of the S. sciuri mecA can efficiently participate in cell wall biosynthesis and build a cell wall using the cell wall precursors characteristic of the S. aureus host.

scholarly journals Real-Time Monitoring of Interactions between Solid-Supported Lipid Vesicle Layers and Short- and Medium-Chain Length Alcohols: Ethanol and 1-Pentanol

Biomimetics ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 8 ◽  
Author(s):  
Shova Neupane ◽  
George Cordoyiannis ◽  
Frank Uwe Renner ◽  
Patricia Losada-Pérez
Keyword(s):  
Real Time ◽  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Model Systems ◽  
Lipid Vesicle ◽  
Label Free ◽  
General Anesthetic ◽  
Medium Chain Length ◽  
Time Interaction ◽  
High Concentrations

Lipid bilayers represent the interface between the cell and its environment, serving as model systems for the study of various biological processes. For instance, the addition of small molecules such as alcohols is a well-known process that modulates lipid bilayer properties, being considered as a reference for general anesthetic molecules. A plethora of experimental and simulation studies have focused on alcohol’s effect on lipid bilayers. Nevertheless, most studies have focused on lipid membranes formed in the presence of alcohols, while the effect of n-alcohols on preformed lipid membranes has received much less research interest. Here, we monitor the real-time interaction of short-chain alcohols with solid-supported vesicles of dipalmitoylphosphatidylcholine (DPPC) using quartz crystal microbalance with dissipation monitoring (QCM-D) as a label-free method. Results indicate that the addition of ethanol at different concentrations induces changes in the bilayer organization but preserves the stability of the supported vesicle layer. In turn, the addition of 1-pentanol induces not only changes in the bilayer organization, but also promotes vesicle rupture and inhomogeneous lipid layers at very high concentrations.

Influence of pericardial suction blood retransfusion on memory function and release of protein S100B

Perfusion ◽  
2004 ◽  
Vol 19 (6) ◽  
pp. 337-343 ◽  
Author(s):  
S Svenmarker ◽  
K G Engström ◽  
T Karlsson ◽  
E Jansson ◽  
R Lindholm ◽  
...  
Keyword(s):  
Artery Bypass ◽  
Memory Function ◽  
Cerebral Injury ◽  
Cell Saver ◽  
Level Increase ◽  
A Cell ◽  
Male Patients ◽  
High Concentrations ◽  
Protein S100b ◽  
To Receive

Background: To study the influence of pericardial suction blood (PSB) on postoperative memory disturbances and release patterns of protein S100B during and after cardiopulmonary bypass (CPB). Methods: Sixty male patients admitted for coronary artery bypass surgery were prospectively randomized to receive PSB either by using conventional cardiotomy suction retransfusion or after cell-saver processing. Results: The concentration of S100B rose during the period of CPB from 0.065±0.004 to 0.24±0.001 mg/L (p<0.001). PSB contained 18.0±1.7 mg/L of S100B. Direct retransfusion from the cardiotomy reservoir made the systemic level increase to 1.42±0.19 mg/L compared to 0.25±0.02 mg/L using a cell-saver. Signs of postoperative memory dysfunction (> 1 SD) were discovered in one of three tests, but were unrelated to technique of retransfusion. No associations were found between serum concentrations of S100B and memory function. Conclusion: In this study, retransfusion of PSB during cardiac surgery appeared not to cause memory disturbances. PSB contained high concentrations of protein S100B making its use as a marker of cerebral injury unsuitable.

Characterization of an anaerobic soil enrichment capable of dechlorinating high concentrations of tetrachloroethylene

1997 ◽  
Vol 36 (6-7) ◽  
pp. 117-124 ◽  
Author(s):  
Tae Ho Lee ◽  
Masaharu Yoshimi ◽  
Michihiko Ike ◽  
Masanori Fujita
Keyword(s):  
Yeast Extract ◽  
Enrichment Culture ◽  
Nutritional Requirement ◽  
Soil Enrichment ◽  
Dechlorinating Bacteria ◽  
Potential Alternative ◽  
Curved Rods ◽  
High Concentrations ◽  
Vitamin Mixture

An anaerobic soil enrichment culture could dechlorinate high concentrations of tetrachloroethylene (PCE; 150 mg/liter nominal concentration; approximately 58 mg/liter in aqueous concentration) nearly stoichiometrically to cis-1,2-dichloroethylene (cis-DCE) via trichloroethylene (TCE) at high rates; a maximum dechlorination rate was 0.4 μmol of PCE transformed/mg volatile suspended solids per hr, using citrate as an electron and carbon source and yeast extract as a nutritional requirement. This dechlorinating activity was comparable with those of the previously-reported, efficient bacterial cultures. Some substrates such as pyruvate, succinate, formate, acetate, and acetate with H2 could replace citrate but propionate could not, and yeast extract could be replaced by a vitamin mixture. However the PCE dechlorination rate decreased more than threefold by the addition of the vitamin mixture, suggesting that the vitamin mixture could not be a complete supplement for the nutritional requirement. Optimal pH and temperature of the enrichment for PCE dechlorination were 7 and 30 °C, respectively. Dechlorination of PCE was completely inhibited by the addition of NO3− and NO2− as potential alternative electron acceptors. S2O3−2 and SO3−2 delayed PCE dechlorination but SO4−2 had no significant effect on PCE reduction. 2-bromoethanesulfonic acid (BES, an inhibitor of methanogenesis) also showed no influence on PCE dechlorination, suggesting methanogens were not concerned with PCE removal in this enrichment. Further, microbial investigations on the enrichment showed that it contains four types of bacteria; cocci, large rods, curved rods, and small rods. The small rods seemed to nutritionally support the PCE dechlorinating bacteria, presumably the curved rods.

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