IN MEMORIAM: LOUIS S. “BUDDY” DIAMOND (1920–2009)

Louis Stanley Diamond, known to many as ‘‘Buddy,’’ who died on 6 September 2009, was a major figure in the history of parasitology research. Although best known for his fundamental and lasting contributions to the study of Entamoeba histolytica, the causative agent of amoebic colitis and amoebic liver abscess, his impact on research into many parasitic protists was significant. He was an early member of the Society of Protozoologists, the forerunner of the International Society of Protistologists, was its President in 1983–1984, and was honoured with a Festschrift in 1995. Buddy was born and raised in Philadelphia, the son of a doctor. His interest in protists began at an early age, when at the age of 14 seeing a Paramecium in a high school zoology class inspired him to save up and purchase his own microscope. He went on to the University of Pennsylvania where the influence of David H. Wenrich and Robert M. Stabler led him towards the parasitic protists; this was also where he first encountered E. histolytica. Graduating in 1940, he moved on to the University of Michigan where he obtained a Master of Science degree in Parasitology. He served in the U.S. Army Air Force and later the U.S. Army as a medical technician, spending much of his time screening thousands of stool specimens for parasites, and published his first paper, on a rapid staining technique for intestinal protists (Diamond 1945). During this time he encountered two important people in his career: Franklin G. Wallace, later to be his Ph.D. supervisor, and Leon Jacobs, who brought him to the National Institutes of Health. Buddy continued his military service in the Army Reserve until 1980. His dissertation at the University of Minnesota under the guidance of Franklin Wallace was on the trypanosomes of frogs, describing species and establishing life cycles. In 1951 Buddy moved on to the U.S. Fish and Wildlife Service in Maryland, where he worked mostly on the trichomonads of waterfowl, and then to the Animal Parasite Laboratory of the U.S. Department of Agriculture (USDA) while writing up his Ph.D. thesis, which took until 1958! In part this was due to the pressures of work and having a growing family, but mostly it was due to Buddy’s dislike of writing; he was always very critical of his own scientific writing ability. While at the USDA, Buddy developed the first of the many parasite cultivation media for which he became well known, trypticase yeast extract maltose (Diamond 1957), frequently referred to simply as TYM or ‘‘Diamond’s medium. ’’ This medium, used primarily but not exclusively for the axenic cultivation of trichomonads, is so reliable and produces such abundant growth that it is still used widely to this day, and the paper in which it is described has been cited many hundreds of times. Having finally completed his Ph.D., he was soon recruited by Leon Jacobs to the newly established Laboratory of Parasitic Diseases at the NIH in Bethesda, MD, where he was to remain for the rest of his career. The NIH had a long history of work on E. histolytica. Both Charles W. Rees and Leon Jacobs had attempted and failed to obtain axenic cultures over the preceding decades, although monoxenic cultures with either bacteria or Trypanosoma cruzi as the associated organism had been generated. Within a year and a half, Buddy had obtained the first ever axenic cultures of E. histolytica. He modestly claimed later that serendipity had a lot to do with it—his choice of strain, his previous experience of developing media, the existence of monoxenic cultures—but the fact remains that he had achieved success where many great amoebiasis researchers had failed. Indeed, many thought axenic cultures might be impossible. His results were published in Science (Diamond 1961) and the ‘‘modern era’’ of Entamoeba research began. Over the following decades, the complex diphasic medium in which axenic cultures were first obtained was replaced by a series of alternative monophasic media that were simpler to make and use, and gave higher yields (Diamond, Harlow, and Cunnick 1978). These opened up amoebiasis research to biochemical, immunological, and eventually molecular investigations. Modifications of his media made the same range of studies possible for Trichomonas and Giardia. Researchers in Buddy’s laboratory at the NIH were the first to study the DNA of E. histolytica (Gelderman et al. 1971a, b) and he lived long enough to see the publication of the organism’s genome sequence (Loftus et al. 2005). Indeed, although he finally retired from the NIH in 1994, he was heavily involved in the initial planning for the genome project in 1998. The above description of his research career perhaps gives the impression of a narrow focus on the cultivation of E. histolytica, but this is far from the truth. His professional interests ranged widely within amoebiasis research and into various luminal and other protistan parasites. He never lost sight of the fact that E. histolytica causes a potentially fatal disease that kills thousands annually, mostly in developing countries. This led to long associations with researchers in both India and Mexico in particular. His links with India spanned most of his career and he visited the country 19 times to foster collaborations with Indian scientists, including the prominent gastroenterologists Om Prakash of the All Indian Institute of Medical Sciences in Delhi and Kamal Jalan of the Kothari Institute for Gastroenterology in Kolkata. Likewise young Indian researchers were welcomed to his lab and long relationships, both personal and professional, developed with several. His links with Mexico started in the early 1970s when he was invited to participate in one of the first ‘‘Seminars on Amebiasis,’’