BectonDickinson RVCSSystems ADVANCESIN CELLBIOLOGY

The Fluorescence Activated Cell Cell Cycle after Simian test of mouse spleen cells reacted with Sorter (FACS) has become a powerful Virus-40 Infection varying dilutions of rabbit anti-mouse means of identifying and separating FACS has been used to study the T-cell antiserum plus complement has cells and cell constituents according to interplay between Simian Virus-40 shown that as antiserum concentration distinctive properties of FLUORESCENCE (SV-40) and host cells after infection increases, the percentage of cells in the and SIZE.FACS makes possible multi- of growing cell cultures. Both mock- dead subpopulation also increases. parameter measurement of individual and SV-40 infected cultures have been cells, providing the distribution of Sorting of Erythrocytes harvested at 24 to 48 hours after infec Containing Malaria Parasites these measurements in a sample. tion, stained for DNA content, and Plasmodium berghei-mtecied mouse Evaluation against operator-selected analyzed with FACS for cell cycle dis criteria, at rates to 5,000 cells per tribution. Infected cultures exhibited a erythrocytes can be analyzed and second, forms the basis for physical marked shift to above average G2 sorted on the basis of parasite DNA separation of viable subpopulations. content. Infected cells, treated with a DNA content by 24 hours after infec vital DNA-binding dye, fluoresce FACS measurements have been docu tion, and remained in this state for at mented for sensitivity to as few as with intensity corresponding to the least 24 hours further, indicating that number of parasites contained. Unin- 3,000 fluorescent molecules per cell. after infection, cycling cells completed Light-scatter measurements are sensi one round of DNA synthesis, but fected cells are nonfluorescent. tive to particles as small as 0.3 micron remained undivided. Measurements of light scatter and in diameter, and can be used to detect fluorescense intensity from each cell viability, without staining, in Live/Dead Cell Enumeration are displayed as a correlated dot plot, The forward- as shown. Sorting of homogenous populations such as angle light- lymphocytes. FACS Systems are ac uninfected from cepted as the standard of comparison scattering measure infected cells enables for quality, performance and reliability, ment of FACS can With4 i Parasites subsequent studies. and are in daily use in top laboratories be used to discrimi nate viable and With 3 Parásito-, For additional infor worldwide. Following is a brief view mation, including an of recent FACS advances: nonviable cells in homogeneous popu With 2 Parásitos extensive bibliography, lations, such as call or write lymphocytes. FACS With 1 Parasite Becton Dickinson analysis during a FACS Systems. lymphocytotoxicity Uninioctod CVils BECTON DICKINSON FACS Systems 490-B Lakeside Drive Sunnyvale, CA 94086 (408) 738-8558; TWX 910 338 2026 Jan Van Rijswijcklaan 105-107 Bus 2 2000 Antwerpen, Belgium 031/16.01.57; Telex 846 720% COVER LEGEND.

then at the University of Texas, produced in Drosophila exposed to X-rays [Science (Wash. D.C.), 66: 84-87, 1927]. For this first artificial trans of the gene, Muller won the Nobel Prize for medicine or physiology in 1946. The first production of mutation by chemicals was reported in 1946 by Charlotte Auerbach (b. 1899) and her associates at the University of [Science (Wash. D.C.), 705: 243-247, 1946]. They exposed Drosophila to sulfur and nitrogen mustards. Research on chemical was expanded by the introduction of microbial systems for such testing, especially after the introduction of activation of chemicals that require metabolic conversion. This was developed by Bruce N. Ames (b. 1928), of the University of California at Berkeley, using a Salmo nella histidine mutant for mutation detection and acti vation of the chemicals by liver microsomes (Proc. Nati. Acad Sci. U. S. A., 70: 2281-2285, 1973). A review and summary of identifying chemicals causing mutations and cancer is by Ames [Science (Wash. The neoplastia change in cells and the transmission D.C.), 204: 587-593, 1979]. A more extensive and of the change to descendants to cells suggest that critical examination of the relation of mutagenic activ neoplastic transformation involves a permanent alter ity in the Salmonella typhimurium system and known ation in the genetic material of the cell. The nature of or suspected carcinogens is by S. J. Rinkus and M. the alteration resembles a mutation. Somatic mutation S. Legator (Cancer Res., 39: 3289-3318, 1979). indeed has been one of the prominent theories of Pictured are (left to right) Drs. Muller, Auerbach, cancer causation since the earliest days of research and Ames. We are indebted to Drs. Auerbach and on cancer and on . Ames for their portraits and to the Indiana University The study of the role and relationship of mutation to for the portrait of Dr. Muller. The photograph of D. neoplasia accelerated following demonstrations that melanogaster mutants is by courtesy of the Brookha- many chemicals that are carcinogenic in animals also ven National Laboratory. The four plates of the Ames produce mutation in animal and microbial systems. test are: A, spontaneous revertants; ß,furylfuramide The first demonstration of induced mutation was (AF-2), 1 /¿g;C, aflatoxin B^ 1 jug; D, 2-aminofluorene, achieved in the fruit fly, , the 10 jug. The photograph is by courtesy of Dr. Ames. material developed for genetic studies by Thomas Hunt Morgan. Herman Joseph Muller (1890-1967), M. B. S.