Microbiologist, Emeritus Professor, Oxford University, England.
Mandelstam was married twice: first to Dorothy Hillier, and from 1975 until his deathto Maureen Dale, who survives him togetherwith the son and daughter of his first marriage
Joel Mandelstam was a pioneer in using bacteria to study fundamental biological phenomena, such as development, which had more usually been investigated in higher organisms. The latter part of his career was spent in research into spore formation, a feature of certain bacteria.
Joel Mandelstam was born in Johannesburg to Leo and Fanny Mandelstam, a Jewish couple of Lithuanian origin, and educated at Jeppe High School. While studying for a BSc at the University of Witwatersrand he initiated and ran, together with a group of friends, a voluntary night school, teaching mainly reading, writing and arithmetic to adult Africans who had had no formal education. From 1942 to 1947 he was a Research Assistant to Dr. Joseph Gilman at the Medical School in Johannesburg.
In 1947 Mandelstam came to London to work for a PhD with John Yudkin on “enzyme adaptation”, the synthesis in microbes of a new enzyme in response to the introduction into their environment of a substance on which the enzyme acts. On moving to the National Institute for Medical Research at Mill Hill, northwest London, he continued to pursue his interest in this phenomenon.
Enzyme adaptation was well known as a characteristic of growing bacteria, but, in a series of incisive experiments in the late 1950s and early 1960s, Mandelstam showed that starved bacteria could also make new enzymes and that they did this largely by degrading proteins that they no longer needed and recycling the constituent “building blocks” (the amino acids). Thus proteins, which had previously been thought to be stable, were in fact in a state of turnover.
This important discovery, broadly generalisable across biology, helped to establish Mandelstam’s reputation, and this was further enhanced by his unravelling the complex regulation of a multi-enzyme metabolic pathway in the soil bacterium Pseudomonas fluorescens. He was elected to the Royal Society in 1971.
Meanwhile, the Iveagh Professorship of Microbiology at the University of Oxford had become vacant through the death of D.D. Woods in 1964. The electors decided to offer the chair to Mandelstam, whose originality and clarity of thought were already becoming evident, rather than to make the more conventional choice of electing a classical bacteriologist. After some hesitation Mandelstam agreed to accept the professorship.
In the event his tenure was an uninterrupted success. With the opportunity to assemble a larger team of researchers, he initiated an important new project to understand spore formation in the bacterium Bacillus subtilis. He became a leading figure in this field internationally, and over the next 20 years his group made major contributions in finding and characterising the key genes involved in controlling development and in determining when, where and how the genes were turned on and off.
During his time at Oxford Mandelstam trained and mentored a large number of researchers who went on to establish their own independent scientific careers. He was generous in allowing the people in his group to follow their own intuition. Unlike many successful and ambitious scientists, he would not add his name to scientific papers from his lab if he believed that he had not made a sufficient contribution to the work. Nor was he the type of scientists to spend time in self-advertisement by rushing from one international conference to another.
He was soft-spoken, courteous and self-effacing, but his reticence was in no way due to timidity or to a lack of self-confidence. He had a just sense of what he and his group had accomplished, and he took great pleasure in the success of his junior associates. He was not seduced by the Byzantine politics of Oxford administration, and he did not seek power. He seldom spoke at faculty meetings, but when he did he was listened to with respect, since his colleagues appreciated his integrity, objectivity and good judgement.
Mandelstam was married twice: first to Dorothy Hillier, and from 1975 until his death to Maureen Dale, who survives him together with the son and daughter of his first marriage.
Professor Joel Mandelstam, FRS, Biochemist and Microbiologist, was born on 13th November 1919, he died on 20th December 2008 aged 89.