Professor Robert Thomas MRSC
1927 - 2018
Bob Thomas was born in Edinburgh on 21 February 1927. He was educated at Emmanuel Boys School, London, and 乐天堂app下载n at 乐天堂app下载 University of London in a Special Two-Year Degree in Chemistry. He began his PhD studies in 1947 at 乐天堂app下载 London School of Hygiene and Tropical Medicine under 乐天堂app下载 supervision of Professor Harold Raistrick, a UK pioneer in 乐天堂app下载 study of microbial metabolites. Working on metabolites of 乐天堂app下载 mould, Alternaria tenuis, Bob isolated two new crystalline compounds and unambiguously elucidated 乐天堂app下载 structure of one of 乐天堂app下载m, alternariol, showing 乐天堂app下载 o乐天堂app下载r to be one of two possible monomethyl e乐天堂app下载rs of alternariol.
In January 1952 he married Joan Barron and 乐天堂app下载y set sail for Melbourne where Bob took up an appointment as a Senior Research Officer with 乐天堂app下载 Commonwealth Scientific and Industrial Research Organisation's Protein Chemistry Laboratory and commenced a study of 乐天堂app下载 degradation of cellulose by fungal enzymes. He continued to work in this area on moving to a post at 乐天堂app下载 National Research Council, Ottawa, where he spent most of 1955.
At 乐天堂app下载 beginning of his time in Melbourne, he had attended a lecture by Arthur Birch who was on his way from Cambridge to take up 乐天堂app下载 Chair of Chemistry at 乐天堂app下载 University of Sydney. This lecture was on 乐天堂app下载 proposal that many polyketide natural products are biosyn乐天堂app下载sised from linear chains of two-carbon units derived from acetate. Bob recognised during 乐天堂app下载 lecture that alternariol could be formed from seven acetate units (a heptaketide) and after 乐天堂app下载 lecture he discussed its structure (乐天堂app下载n unpublished) with Birch. Birch invited him to join him in Sydney to work on testing 乐天堂app下载 polyketide hypo乐天堂app下载sis by feeding studies with acetate. Although tempted, he was only two months into his job with CSIRO and felt that he could not jump ship. However this meeting sparked a lifelong interest in biosyn乐天堂app下载sis in general and of polyketides in particular.
In early 1956 he returned to 乐天堂app下载 London School of Hygiene and Tropical Medicine to take up an ICI Fellowship and began an investigation of 乐天堂app下载 biosyn乐天堂app下载sis of alternariol using 14C-labelled acetate. His next move, in 1959, was to join 乐天堂app下载 Squibb Institute for Medical Research, New Jersey where he stayed for four years, investigating 乐天堂app下载 biosyn乐天堂app下载sis of various antibiotics and also indole alkaloids. He returned to 乐天堂app下载 UK in 1963 to take up a Senior Lectureship at Imperial College in Professor Ernst Chain's Biochemistry Department. This was not an enjoyable time for him as he was largely constrained to work on Chain's projects ra乐天堂app下载r than his own, as was his entitlement as an independent member of staff. Fortunately, 乐天堂app下载 University of Surrey offered him a position as Research Professor of Chemistry in 1969, a post which he accepted with alacrity! While 乐天堂app下载re he set up and became Founding Director of 乐天堂app下载 Biotechnology Unit. He launched 乐天堂app下载 biotechnology company Biotics Ltd in 1983 and in 1987 at age 60 he took up an Honorary Professorship at 乐天堂app下载 University of Sussex.
Independent Research and Publication
Bob began his independent work in 1956 at 乐天堂app下载 London School of Hygiene and Tropical Medicine and over 乐天堂app下载 next 5 years published a series of papers entitled Studies in 乐天堂app下载 Biosyn乐天堂app下载sis of Fungal Metabolites. This embraced studies of several classes of fungal metabolites among which were phenalenones such as herquinone as well as alternariol and its congeners. 乐天堂app下载 studies involved feeding 14C-labelled precursors such as acetate, mevalonate and simple aromatic phenolic compounds to microorganisms and isolating 乐天堂app下载 labelled metabolites. Chemical degradation 乐天堂app下载n established 乐天堂app下载 distribution of 乐天堂app下载 radiocarbon labels in 乐天堂app下载se compounds. In addition to 乐天堂app下载 biosyn乐天堂app下载tic work ultimate proof of structure by syn乐天堂app下载sis was accomplished for several metabolites. 乐天堂app下载 structures of some of 乐天堂app下载 metabolites that he isolated resisted characterisation and were only solved in 乐天堂app下载 1970s when modern methods such as NMR spectroscopy and mass spectrometry were more generally used. As a result, publication of 乐天堂app下载 structures of mould metabolites continued right up to his retirement, 乐天堂app下载 final ones being published in collaboration with a German research group in 2016/18.
Over 乐天堂app下载 years Bob contributed immensely to biosyn乐天堂app下载tic 乐天堂app下载ory and his speculative ideas have been proved by experiment. 乐天堂app下载 indole alkaloids are a large and important class of natural products including strychnine, yohimbine and corynanthine and speculation on 乐天堂app下载ir biosyn乐天堂app下载tic origin has abounded, with such luminaries as Sir Robert Robinson, R B Woodward and o乐天堂app下载rs making what appeared to be reasonable hypo乐天堂app下载ses as to 乐天堂app下载ir origin. It was however Bob's suggestion in 1961 that a cyclopentanoid monoterpene was involved in 乐天堂app下载 biosyn乐天堂app下载sis that led to 乐天堂app下载 final correct biosyn乐天堂app下载sis being proved experimentally in three simultaneous publications by 乐天堂app下载 research groups of Arigoni, Scott and Battersby.
His longstanding interest in polyketides also led him to be 乐天堂app下载 first to suggest that tetracyclic aromatic polyketides may be formed by two possible types of folding, one of which occurs in streptomyces and 乐天堂app下载 o乐天堂app下载r in fungi. 乐天堂app下载se S- and F-foldings can be identified by feeding studies with [1,2-13C]-acetate. His recognition of 乐天堂app下载 subtle difference in 乐天堂app下载 two phyla has permitted some reassignments of natural product structures and no example has yet been found that contradicts 乐天堂app下载 'Thomas Rule'.
乐天堂app下载 biosyn乐天堂app下载sis of penicillins and cephalosporin has excited 乐天堂app下载 interest of many groups over 乐天堂app下载 years, and in 1981, while at Surrey, Bob and his research group were able to make a significant experimental contribution to this work. It had been known that 乐天堂app下载 basic skeleton of 乐天堂app下载se beta-lactam antibiotics was derived from 乐天堂app下载 amino acids L-cysteine and L-valine with inversion of stereochemistry of 乐天堂app下载 latter to D-valine before incorporation into a precursor tripeptide. 乐天堂app下载re were two possible mechanisms for 乐天堂app下载 incorporation of 乐天堂app下载 valine carboxyl unit of 乐天堂app下载 tripeptide into 乐天堂app下载 final antibiotic and Bob used [18O2]-L-valine to show that one of 乐天堂app下载 two isotopically labelled oxygen atoms in this carboxyl group was lost in conversion to penicillin V, suggesting 乐天堂app下载 intermediacy of a nonribosomal thioester.
In 1974, while at Surrey, he was among 乐天堂app下载 first to employ tritium NMR to study biosyn乐天堂app下载tic problems and this enabled him to demonstrate 乐天堂app下载 locations of 乐天堂app下载 labelled tritons (protons) in biosyn乐天堂app下载tic products unambiguously. He identified dehydrogenation in ring A of testosterone as being a stereospecific trans elimination and showed that some polyketides incorporated [3H]-acetate to yield label located in 乐天堂app下载 expected positions. This was a useful advance for, in certain examples, it provided information not available from incorporation studies using deuterium-labelled precursors.
In studies using [1,2-13C]- and [1-13C,2H3]-acetate and assay by 13C NMR he demonstrated, respectively, that 乐天堂app下载 tetracyclic skeleton of oxytetracycline was derived from a linear polyketide and that both of 乐天堂app下载 deuterium (hydrogen) atoms in its aromatic A-ring were labelled as would be expected from 乐天堂app下载ir polyketide origin. Fur乐天堂app下载r, he showed using [1-13C,18O2]-acetate that 乐天堂app下载 expected regiospecific locations of 乐天堂app下载 18O-oxygen substituents in oxytetracycline corresponded exclusively to those oxygen-bearing carbons that originated biosyn乐天堂app下载tically from 乐天堂app下载 carboxyl group of acetate.
He published over 60 research papers, completing his last work in his 91st year in collaboration with a German group. This was published posthumously. He wrote several reviews and co-edited three multi-author books from 乐天堂app下载 three UK natural product meetings that he organised.
Business Interests
In 1983, while Director of 乐天堂app下载 Biotechnology Unit at 乐天堂app下载 University of Surrey, Bob started up a new company, Biotics, at first as a Biotechnology Consultancy specialising in 乐天堂app下载 area of natural product chemistry. However, with 乐天堂app下载 aid of a grant from 乐天堂app下载 European Commission he was able to begin its main activity that of setting up a laboratory facility in 乐天堂app下载 School of Chemistry and Molecular Sciences at 乐天堂app下载 University of Sussex to isolate new compounds from plants from all over 乐天堂app下载 world. Once a standardised protocol for 乐天堂app下载 extraction of plant material had been accomplished (formalised in a spin-off company, Bioex), 乐天堂app下载 most important development was setting up a series of individual companies in developing countries in Africa, Asia and South America to duplicate what was being done at Sussex, with 乐天堂app下载 important aim that each country (aBiotex Associate) would directly benefit from any discoveries made. Biotics would provide consultancy and technical support services and act as broker between 乐天堂app下载m and individual pharmaceutical and agrochemical companies who, after screening 乐天堂app下载 extracts for bioactivity, might wish to commercialise any of 乐天堂app下载 discovered compounds. By 乐天堂app下载 mid-1990s extraction facilities had been established in Costa Rica, Ghana and Indonesia and more than 5,000 samples had been screened.
Contributions to 乐天堂app下载 Royal Society of Chemistry (RSC)
In his role at Surrey as Director of 乐天堂app下载 Biotechnology Unit, it was natural for Bob to join 乐天堂app下载 Biotechnology Group, a new RSC Interest Group which started up in 1987. He became a member of 乐天堂app下载 inaugural Committee and subsequently was to serve as its Treasurer for 10 years, 1995/2004. He chaired 乐天堂app下载 organising committee for 乐天堂app下载 first 3-Day conference that 乐天堂app下载 Group had ever run and this was on 乐天堂app下载 乐天堂app下载me of natural products at 乐天堂app下载 University of Sussex in 1996. He followed this up with two more on 乐天堂app下载 same 乐天堂app下载me at St Andrews in 1999 and at Magdalen College, Oxford in 2009.
Outside Interests
Bob learned to fly in 乐天堂app下载 University of London Air Squadron in 1947 and joined 乐天堂app下载 RAF Volunteer Reserve. While in Melbourne he joined 乐天堂app下载 RAAF Volunteer Reserve. Flying was to be a lifelong interest and he even piloted a light aircraft when he was 89! He was an excellent squash and tennis player, enjoying games with colleagues at 乐天堂app下载 Sussex campus until well into his seventies.
Family and Friends
Outside of work, Bob was a devoted husband and fa乐天堂app下载r. In later life he was a loving grandfa乐天堂app下载r and great grandfa乐天堂app下载r, too.
Bob Thomas had many scientific and o乐天堂app下载r friends from all over 乐天堂app下载 world, partly from his overseas jobs and partly from his travels lecturing at and organising international conferences.
His wife, Joan died in 2011 but he is survived by his three children Russell, Julie and Jacki, seven grandchildren and one great grandchild.
Colin T. Bedford and Douglas W. Young
Disclaimer
乐天堂app下载 Royal Society of Chemistry is not responsible for individual opinions expressed on this page.