Donald Burdick

Chemical composition and lipoxygenase activity in soybeans as affected by genotype and environment.

Environmental and genetic influences on the chemical composition and lipoxygenase activity of 24 soybean genotypes (groups IV-S and V) were determined. The soybeans were grown at two climatically different locations within the state of Georgia. Oil and protein contents and fatty acid composition of the oil in soybeans were affected by the environment. Five genotypes from group IV-S has a fatty acid composition of the oil different from the other genotypes in the group. These differences appeared to be genetically controlled. The level of lipoxygenase activity in soybeans also appeared to be genetically controlled and not influenced by the environment. The study indicated that soybean genotypes could be selected for a specific climatic region based on oil fatty acid composition and lipoxygenase activity.

A NEW TECHNIQUE FOR THE DISPERSION OF INSOLUBLE MATERIALS IN AGAR MEDIA

Nutritional studies of microorganisms utilizing insoluble carbon compounds or other ingredients in agar media require that the insoluble substances be evenly dispersed. Several methods have been reported for preparing media containing such insoluble carbon sources as cellulose. In one method, washed silica gel (1, 3, 7, 8, 10) was overlaid with cellulose; in another, washed sand (2, 5, 7) or agar (3, 4, 7) was overlaid with cellulose. Skinner (6) used an additional carbon source (carboxymethylcellulose) to suspend the cellulose particles in the agar. These techniques require much time in preparation or addition of other carbon sources to achieve dispersion. During autoclaving the insoluble carbon compounds settle and tend to pack in the bottom of the tube (FIG. 1, tube a). Shaking the tube after autoclaving is of little value because the insoluble material again settles toward the bottom during solidification in the slanting position. FIGURE 1, (tube b) shows a tube which was shaken by hand after autoclaving and allowed to solidify in a slanting position. We have devised a technique to redisperse insoluble materials and keep them dispersed until the agar slants solidify (FIG. 1, tube c.). We have successfully used this technique with cholesterol, calcium carbonate, and the following types of cellulose: pebble mill ground filter paper, a-cellulose, microcrystalline types 19 and 38 micron sizes, and the wood cellulose solka-floc. The basal mineral salts or other solution to be used is placed in a suitable container with a stirring bar and placed on a heating-stirring apparatus. The agar is added and the entire solution stirred while being brought to a boil. The insoluble compound is then added and stirring is continued until it is dispersed. The medium is then dispensed into suitable tubes containing small magnetic stirring bars. These bars should be small enough 178

Interfacing a programmable electronic calculator with an automatic amino acid analyzer.

Abstract The rapid calculation of data from an automatic amino acid analyzer by a programmable electronic calculator is now possible. The programmable electronic calculator offers a less expensive and more flexible alternative to large computers. Typically, data in the form of retention times and peak areas are read from a punched tape and converted into final values with a minimum of data handling. A digital integrator, teletypewriter with tape punch and reader, tape editor and printer also are required. A mathematical program is described that has been devised to convert raw data from a 4-h protein hydrolyzate run into final values. The final printout presents in tabular form each amino acid as a percentage of the sample dry weight and crude protein. The total weight percentage of amino acids and percentage recovery of protein based on Kjeldahl nitrogen are also calculated. Other features of the program include the ability to eliminate up to 20 extraneous peaks from the sample and to correct for sampling errors with the aid of internal standards. Amino acid molecular weights and color constants, which are also calculated, are stored without destruction so as to permit the calculation of an unlimited number of samples from the same set of standards.