Cell disruptor

Frequency and Intensity. Most ultrasonic baths operate in the 30 -80 kHz range. Frequency is rarely an important factor, provided the frequency is low enough to permit cavitation. The cell disruptors normally adapted for sonochemical uses operate at 20 kHz. The intensity must be enough to produce cavitation. Beyond that, optimum intensities for heterogeneous reactions have not been determined. 

For the specific amplification of C. moewusii genomic hydA DNA, a C. moewusii colony was scraped from an agar plate and resuspended in 10 mM Tris-HCl, 10 mM EDTA and 150 mM NaCl. After disrupting the cells (Cell disruptor B 15, Branson, Danbury, USA), 2 pi of the resulting suspension was used directly in the PCR. 

RiZn. Dialkylzinc reagents can be prepared from an organic halide, lithium wire, and zinc bromide at 0° in toluene-THF by sonication in a cell-disruptor generator. Yields are essentially quantitative. Diarylzinc reagents and dimethylzinc can be prepared by sonication in an ultrasonic laboratory cleaner. 

Figure 10-3. Sonicator or sonic cell disruptor showing the sonic wave generator in the background and the titanium transducing element in the foreground. Needle tips capable of operating in small test tubes may be interchanged with the larger tip (arrow) shown here. (Courtesy of Heat Systems-Ultrasonics, Inc., Plainview, N.Y.)...

Fisher Scientific) was emulsified into aqueous soap solutions of 0.25 w% each of sodium laurate and sodium oleate prepared from sodium hydroxide, lauric acid (Aldrich Gold Label) and oleic acid (Fisher Purified). Coarse emulsions were used for microscopy (as in Figure 2), but fine emulsions (with droplet sizes of about 0.2 microns), used for determination of middle phase film thicknesses, were made by ultrasonication with a cell disruptor. 

One of the original uses of power ultrasound in biochemistry was to break down biological cell walls to liberate the contents (indeed many ultrasonic horn systems were first marketed as cell disruptors). Subsequently it has been shown that power ultrasound can also be used to produce a positive effect on enzyme activity. If the intensity is too high however the enzymes can be denatured. 

The aliquot designated for extraction at neutral pH was extracted three times, with fresh 100-mL acetone/hexane (50/50). An ultrasonic cell disruptor, in pulsed mode at 50 percent duty cycle, was employed to enhance the contact between the extraction solvent and soil. Following each extraction, the soil was allowed to settle, the solvent decanted, and the combined supernatants from the neutral pH extraction were dried through a column of anhydrous sodium sulfate (5-cm bed height 3-cm diameter). Concentration of the extract was performed using a Kuderna-Danish evaporator. Final volume was adjusted to 1 mL using nitrogen blowdown evaporation. 

It is significant that manufacturers increasingly are seeking to incorporate containment features into the design of process equipment such that physical enclosure may not be necessary, except at the highest containment levels. Particular examples of containment design for centrifuges and cell disruptors are described elsewhere in this book (see chapter 9) but the... 

Stewart, I.W. and Deans, J.S. (1990). Containment testing of cell disruptors, Warren Spring Laboratory report no LR 767 (BT), Gunnels Wood Road, Stevenage, Herts., March. 

This limitation has led to the development of a number of systems that can be used to induce cavitation in homogeneous reaction mixtures. The cup-horn reactor was originally designed for use by biochemists as a cell-disruptor (Fig. 11). Its advantages are that it can deliver greater acoustic intensities and is potentially easier to thermostat. Its disadvantages are similar to those of the cleaning bath in that it is very sensitive to liquid levels and the... 

This problem was overcome by use of a cell-disruptor type ultrasound generator. This modification permitted much greater control of the sonication conditions and allowed addition of 1°, 2°, 3° alkyl and allylic groups in essentially quantitative yield within 10-20 min [144] (Scheme 63). 

Quinn CF, Freeman JL, Reynolds RJB, Cappa JJ, Fakra SC, Marcus MA, Lindblom SD, Quinn EK, Bennett LE, Pilon-Smits EAH (2010) Selenium hyperaccumulation offers protection from cell disruptor herbivores. Plant Physiol 153 1630-1652 Quinn CF, Prins CN, Freeman JL, Gross AM, Hantzis LJ, Reynolds RJB, Yang S, Covey PA, Banuelos GS, Pickering IJ, Fakra SC, Matthew A, Arathi MHS, Pilon-Smits EAH (2011) Selenium accumulation in flowers and its effects on pollination. New Phytol 192 727-737. doi 10.1111/j.l469-8137.2011.03832.x... 

For the protein nanocomposite formulation, 400 g of water and 400 g of glycerol were also blended in a large beaker with a mechanical stirring device for two minutes, prior to the addition of 60 g of Cloisite Na. For the untreated system the mixture was then eombined drip-wise with 1200 g of the soy protein using a ten-litre laboratory seale high-speed mixer (HSM-10) for five minutes prior to extrusion similar to the neat protein film. For the ultrasonically treated system the mixture was treated with a point souree ultrasonic device (Branson sonifier model 250 W cell disruptor) for one hour in an iee-eooled environment (as outlined in section 11.2). This mixture was then eombined drip-wise to 1200 g of the soy protein using a ten-litre laboratory seale high-speed mixer (HSM-10) for five minutes prior to extrusion similar to the neat protein film. 

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