Osmotic shock

Duolite C-464 3.0 1.13 Polyacrylic resin with high capacity and outstanding resistance to osmotic shock. 

Physical methods such as osmotic shock, in which the cells are exposed to high salt concentrations to generate an osmotic pressure difference across the membrane, can lead to cell-wall disruption. Similar disruption can be obtained by subjecting the cells to freeze/thaw cycles, or by pressuriziug the cells with an inert gas (e.g., nitrogen) followed by a rapid depressurization. These methods are not typically used for large-scale operations. 

Hi) Poly amines. In many respects the role of poly amines in plant functioning is still mysterious after many years work. They are almost certainly involved in the control of growth and development through their interactions with nucleic acids and membranes (Smith, 1985). There is increasing circumstantial evidence for their involvement, especially of putrescine, in plant responses to a wide range of stresses including pH, Mg deficiency, osmotic shock, cold, SO2 pollution, and cadmium and ammonium toxicity (Smith, 1985). It remains to be determined, however, how, and indeed whether, putrescine accumulation in response to these diverse stresses is beneficial. 

It has also been reported that osmotic shock enhances the biosynthesis of polyamines (Flores Galston, 1982). However, the concentrations of polyamines seem to be too low to account for any significant increase in osmolarity. 

Flores, H.E. Galston, A.W. (1982). Polyamine and plant stress activation of putrescine biosynthesis by osmotic shock. Science, 217, 1259-60. 

Once proteins are transferred into the periplasm they can also be excreted into cultivation media (but with further reduction of the yield). This mainly happens by leakage, which can be enhanced by osmotic shock or cell wall permeabilization (by mutations or enzymatically). However, in some cases passive excretion does not work. There are also strategies with transplantation of active transport proteins for one or both of the membranes [35], but so far they are not that reliable. 

Osmotic shock Media containing 1.0 M sorbitol Expose cells to sorbitol-containing media for 30 min replace with regular media for 30-60 min... 

Macroporous resin beads, due to their mode of preparation, consist of a macroporous internal structure and highly cross-linked areas (>5%). The latter impart the resin with rigidity, whereas the porous areas provide a large internal surface for functionalization, even in the dry state. These macroporous polystyrene-based resins are subsequently modified in various manners, which render them compatible with numerous organic solvents. Furthermore, they show high resistance toward osmotic shock, but can be brittle when not manipulated carefully. 

The best-studied systems to date are those for the uptake of maltose, histidine, siderophores and vitamin B12. Typical of all the ABC-type importers are the soluble binding proteins, which bind the substrate with high affinity. Early studies revealed that many binding proteins could be extracted from Gramnegative bacteria by an osmotic shock procedure, giving rise to the term osmotic-shock-sensitive transport systems. It still holds true that the majority... 

Permeable Cell Assay for high-throughput measurement of cellular ATP synthetic activity (4). In this assay, osmotic shock and Triton X-100 treatment made bacterial cells permeable for ATP Discharged ATP reacted with external luciferase and is detected as bioluminescence. An increased bioluminescence is observed with permeable cells, whereas it is not observed with standard ATP solution and heat-inactivated permeable cells. The cellular ATP synthetic activity is calculated from the slope of increasing bioluminescence. Permeable Cell Assay is simple and rapid with a small amount of cell culmre for quantification of ATP synthesis. 

Osmotic shock by rapid dilution of glucose makes ATP permeate through the bacterial membrane and glucose also acts as carbon source for ATP synthesis. The osmotic shock showed better reproducibility than authentic freeze-thaw treatment. Glucose could be replaced with other sugars when it is required. 

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