Analysis of bacteriophage T4 coat proteins by two-dimensional electrophoresis and computerized densitometryWe have designed treatment conditions which allow analysis of the coat proteins of bacteriophage T4D+ by high resolution two-dimensional electrophoresis. The best results were obtained when the mature phage particles were subjected to hypertonic lysis and DNase treatment before solubilization with sodium dodecyl sulfate (SDS). Samples containing 250 pg protein gave the optimum resolution, producing 45 spots as visualized by Coomassie Blue staining. Computerized densitometry measurements showed that these proteins range in relative abundance from less than 0.22 % to 11.8 % of the total. Bacteriophage T4 has a genome size large enough to accomodate about 170 genes, each consisting of 1000 base pairs [ll of which about 65 essential and 70 non-essential genes have been identified [21. However, electrophoretic analysis of SDS-solubilized T4 coat proteins has only resolved 21-25 bands in the protein pattern [3-51. Two-dimensional electrophoresis [61 has been successfully applied to various biological systems in detecting proteins which are not separable by one-dimensional techniques. Hence we have performed the separation of T4 coat proteins in a two-dimensional system. Our initial attempts to solubilize T4 coat protein by the lysis buffer technique of O'Farrell[6] or the SDS Figure I. SDS-polyacrylamide gel electrophoresis of DNase treated and control preparations. Lane [ I ] T4D+ treated with DNase as described in text. Lane [21 untreated control. Molecular weight standards were purchased from Pharmacia Fine Chemicals. Bacteriophage T4D+ and E. coli B strain WU 3610 were generously donated by Dr. R. K. Elespuru. E. coli B (leucine requiring) were grown to midlog phase in M-9 medium supplemented with 10 pg/ml leucine. Cultures were infected with T4D+ at a multiplicity of infeciton of 0.003 and incubated at 37OC for 4 h. Cell debris was removed by centrifugation at 1400 g for 15 min. The supematants were centrifuged at 27,000 g for 1 h. The resultant phage pellets were resuspended in 0.15 M NaCl and stored under chloroform until use. SDSpolyacrylamide gel electrophoresis was perfomed as described by Laemmli [3] in a 10 % slab gel, with a 30 pg protein load. Correspondence: Douglas M. Gersten, Abbreviation: SDS: Sodium dodecyl sulfate method of Ames and Nikaido [71 failed, resulting in poor entry of the proteins into the first dimension electrofocusing gel.The observation by OFarrellL61, that nucleic acids in the sample interfere with isoelectric focusing, suggested that treatment of the phage by hypertonic shock, followed by en-Table 1. Integrated density and percent abundance of each subunit. Subunit No.a) Integrated densityb) % Abundancec) 1 2 3 4 5 6 7 8

I 1Plasma from normal male and female rats was analyzed, after removal of albumin by affinity chromatography, by two-dimensional electrophoresis. The results demonstrated gender differences in two plasma proteins with apparent molecular weights of 70 000 and 84 000 and isoelectric points ranging from 6.2 to 6.4, and 5.1 to 5.5, respectively. Both proteins were found to be more concentrated in the plasma minus albumin (P-alb) fraction of females than males in both Wistar and Sprague-Dawley rats. The 70000 protein is serum albumin which was more completely removed from male plasma than female plasma. A possible mechanism responsible for this difference is discussed. The results support the existence of "maleness" and "femaleness" in blood protein patterns of rats.

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Computer-assisted pattern recognition holds much promise for important applications in clinical medicine.In many instances successful automatic pattern recognition requires an analysis of the texture of a picture by a conventional digital computer, but this procedure involves a type of computing that is presently too time-consuming and expensive for practical application.In response to this situation, we have designed and developed an auxiliary computer called TEXAC (TEXture Analysis Computer).TEXAC can perform most whole picture operations at a rapid television rate of 1/30th of a second, and display the results continuously on color and black and white video monitors.Here we present the architecture of the TEXAC, both the hardware and software systems, and discuss potential biomedical applications and several interesting whole picture operations accomplished by the new computer.