Protein, ultrasonic extraction

Mechanical separation of cellulose fibrils from natural fibre resources may involve the process of grinding to apply shear stress to the longitudinal axis of the fibres, so that the fibrillated fibres will have diameters ranging 20—90 nm (Taniguchi and Okamura, 1998). Ultrasonic extraction is another approach to disrupt the adhesion among the fibrils so as to extract nanofibrils from both cellulosic and protein fibre sources... 

He et al. (2002) used an off-line HPLC/CE method to map cancer cell extracts. Frozen ovarian cancer cells (containing 107 cells) were reconstituted in 300 pL of deionized water and placed in an ultrasonic bath to lyse the cells. Then the suspension was centrifuged and the solubilized proteins were collected for HPLC fractionation. The HPLC separation was carried out on an instrument equipped with a RP C-4 column, 250 mm x 4.6 mm, packed with 5-pm spherical silica particles. Extracted proteins were dissolved in 300 pL of DI water, and lOOpL was injected onto the column at a flow rate of 1 mL/min. Buffer A was 0.1% TEA in water and buffer B was 0.1% TFA in acetonitrile. A two-step gradient, 15-30% B in 15 min followed by 30-70% B in 105 min, was used. The column effluent was sampled every minute into a 96-well microtiter plate with the aid of an automatic fraction collector. After collection, the fractions were dried at room temperature under vacuum. The sample in each well was reconstituted before the CE analysis with 10 pL deionized water. The... 

The effects of ultrasonic treatment and ultrasonic irradiation on the extraction of cottonseed meal have been assessed [56], Results indicated that a combination of enzyme treatment and sonication produced a significantly greater yield of extracted protein than traditional methodologies. 

Power ultrasound has also been found to be effective in the extraction of protein from meat [58]. Ultrasound disrupts the meat myofibrils and this releases a sticky exudate which binds the meat together. The binding strength, water holding capacity, product color, and yields were examined after treatment either with salt tumbling, sonication, or both. Samples which received both salt treatment and sonication were superior in all qualities. Similar results were obtained from a study of the effect of sonication on cured rolled ham [59]. Ultrasonic treatment enhanced the extraction of myofibrillar proteins leading to an increase in the strength of the reformed meat. 

Other AR mediators, such as divalent ion chelators, formaldehyde scavenges, such as citraconic anhydride, metal ions, or proteolytic enzymes can enhance AR in certain cases however, their applications are not universal and, in some cases, may even inhibit immunostaining. As noted above, the removal of steric barriers that restrict access of the antibody to its target epitope is a key component of aR." In this context, heating may serve to promote the extraction of diffusible proteins out of the tissue sections following cross-link reversal or proteolytic treatment, opening physical holes or channels in the tissue sections that allow better penetration of antibodies. The physical process of opening holes or channels within the tissue section also likely explains the modest success of ultrasonics as an AR method. ... 

Alternatively berries can be freeze dried prior to extraction. Dried, berry anthocyanin extracts are dissolved in methanol or ethanol containing 0.1-2.0 % cone. HCl, kept for 5 minutes in an ultrasonic bath and finally cleared by filtration. Deny juice is best acidified with HCl (0.1-2.0 %) for stabilization and diluted with an appropriate solvent. If anthocyanins are extracted from dietary supplements or from processed food products (i.e., beny jam or ice cream), repeated extraction with mixtures of polar organic solvents and aqueous acids is usually appropriate. The aqueous part is most often necessary for dissolution of the other ingredients (e.g., sugars, proteins). 

The detergent sodium dodecyl sulfate (SDS) often efficiently extracts unreduced storage proteins. For SE-HPLC, proteins may be extracted with an SDS-containing buffer similar to the mobile phase. Usually the SDS concentration is increased to 1-2% and the sample is heated to ensure total complexing with protein [8,39]. To extract all proteins without reduction, SDS plus mechanical (ultrasonic) shear may also be used [40,41] but may decrease the size of native glutenin. 

The first stage in the isolation of a protein which is not already in solution, e.g. in plasma or milk, is to release it from cell structures. Cells may be disrupted by homogenization, exposure to hypo-osmotic solutions or to ultrasonic vibrations, or by drying them to a powder with acetone at low temperatures. This latter process also serves to remove lipids and facilitates subsequent extraction of the protein. 

Active extracts were obtained under anaerobic conditions by freezing and ultrasonic-bath treatment, a method to be published elsewhere, Weisshaar, BSger 1984). Omitting a regenerating ATP system, no nitrogenase activity was measured, a clear evidence that both gases are formed by nitrogenase activity (nos. 2,3). Protein content Phormidium 3 mg/ml, Nostoc 7 mg/ ml. The lower rates in Nostoc are due to the heterocyst frequency of 5% only. 

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