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Gerald was appointed to the Department in 1974. His PhD supervisor was Sandy Smith in the early 1970s. Here in his own words are Gerald's recollections.

"Interestingly, my strongest memories of the department relate to my time as an Honours student and PhD student in the period 1968-1972. I suppose that my many years as an academic staff member have run together in my mind and its all somewhat blurred. Several of us were appointed as lecturers in the mid-70s when universities world wide were expanding and taking on new staff. I think that all of us in that bunch have similar recollections of our time in the department and I hesitate to repeat things that will be much better covered by other people. Suffice it to say that after an excellent two-year postdoctoral period with Dwayne Savage in the USA two doors seemed open: stay in the States or return to Otago. Dunedin/Otago has a strange pulling power and I returned in August 1974. Things might have been easier if I had stayed in the USA – one will never know. John Miles was head of department and the new Microbiology Building was in the offing. I’ve enjoyed many productive and interesting years in that building and wonderful collaborations with colleagues overseas. The international aspect of Science is very attractive and rewarding scientifically, and intellectually in general. 

So, back to my postgraduate memories. I came to academic Microbiology indirectly, having first worked as a trainee medical technologist at Dunedin Hospital. The Microbiology lab was the first that I worked in under the inspiring Henry Shott who was chief technologist. Other diagnostic labs did not appeal so much, so I left the training programme and worked for a year or two for the Department of Agriculture at the Invermay veterinary diagnostic laboratory. Then I received a scholarship from the Agriculture Department that enable me to attend university. I knew from the beginning that Microbiology was what I wanted to major in – to the disappointment of the Botany department because of my possible relationship to the great David Tannock of botanical gardens fame. I did not have a plan apart from a Microbiology major when I came to Otago as an undergraduate. Life happens and I ended up with a PhD.

My postgraduate years at Otago were very enjoyable. Sandy Smith let me do pretty much what I wanted to do in terms of experimentation and we had a great supervisor-student relationship. There were few postgrads and of course the technology in those days was extremely simple but nevertheless effective for answering pertinent questions at the time. I have warm memories of:

  1. morning tea in the staff room with John Miles at the head of the table and the academics seated in order of seniority postgrads at the bottom sharing a bench.

  2. Nancy Campbell swearing at the Gestetner copier around the corridor from my room.

  3. Nancy ringing the tea bell in the corridor.

  4. John Miles reading his afternoon mail while listening to essays being read out by Roland Tan and myself.

  5. Chris Kershaw, Jim Solomon and myself chasing sheep around an Invermay paddock – on several occasions. 

Microbiology has become more ‘micro’ over the years. One millilitre was once a small amount to pipette, now one microlitre is child’s play. Bacteria apart from E. coli are hardly ever cultured in university labs and light microscopes are seldom used. One can see a revival coming, however. Metagenomics has a role, but it is impossible to study the physiology of bacteria and gene regulation without cultivation of the organisms in question. Culture of bacteria will return to the fore as we explore bacterial communities inhabiting biomass about which little is yet known. Even in the 21st century, huge lacunae exist in our knowledge of the bacteriological world around us, including gut commensals (symbionts) that I have spent my career studying. Microbiology has an exciting future and much to contribute in developing New Zealand’s export-related industries.

I’ve had a good career – no regrets."

Research Profile -- 1979  

Excerpt from Departmental Review -- 1970 to 1979

This research has principally been concerned with bacteria associated with the gastrointestinal tract of mammals. Previous research has included the isolation of indigenous microbes from the pig stomach and investigations into the epidemiology, mode of transmission and pathogenesis of Salmonella bacteria with particular reference to domestic animals. Information on the survival of Salmonella outside the host animal was obtained from in vitro laboratory experiments and experiments performed under natural environmental conditions. Involvement of the upper respiratory tract of mice and sheep in the transmission of Salmonella was also studied. An experimental model was developed to study the effects of adverse dietary and environmental conditions on Salmonella populations in the gastrointestinal tract of mice. Field studies have demonstrated the presence of Salmonella in the nasal passages of sheep on a farm in which an outbreak of Salmonella infection had occurred. The changes in indigenous microbial population levels and their distribution that occur in the gastrointestinal tract of mice subjected to adverse dietary and environmental conditions have also been investigated.

More recently, indigenous microbes from the gastrointestinal tract of mice have been isolated and characterized. Bacterial groups studied include lactobacilli; bacteroides; coliforms; enterococci; fusiform-shaped bacteria belonging to the genera Clostridium, Fusobacterium and Bacteroides; and spiral-shaped bacteria belonging to the genus Campylobacter. Strains of bacteria from some of these groups have been chosen, because of their particular characteristics, for use in experiments with gnotobiotic, BALB/c mice. The main concern in the gnotobiotic experiments has been to determine which indigenous microbes are responsible for interferring with the establishment of Salmonella in the gastrointestinal tract. Mice associated witil a lactobacillus strain, a bacteroides strain, and two types of clostridia have fewer Salmonella typhimurium present in the ileum, 3 days after intragastric challenge with the pathogen, than do germfree mice. The mechanism of this interference effect is not known. Some indigenous microbes, injected intravenously into conventional mice, increase the resistance of the animal to subsequent intravenous challenge with S. tymphimurium. The resistance of the mice to infection is measured in terms of the number of salmonella present in the spleen of mice five days after challenge. The phenomenon observed in conventional mice has been confirmed using gnotobiotic mice monoassociated with indigenous microbes (an enterococcus or a lactobacillus strain).

Current research involves the effect of diet on the composition and activities of the indigenous microbiota of the gastrointestinal tract of mice. 

Research Profile -- 1995

Associate Professor Tannock's research programme has focussed on the use of molecular biological methods for the study of the mechanisms by which members of the normal microflora colonise the digestive tract and influence the biochemistry and physiology of the human or other mammalian host. These studies have involved the derivation of unique colonies of mice that harbour a normal microflora equivalent to that of conventional animals but which lack a specific bacterial group (e.g. lactobacillus-free, streptococcus-free). These animals provide an experimental system with which the significance of microbial colonisation factors and influences can be investigated. The research is funded principally by grants from the NZ Dairy Research Institute, The Wellcome Trust (London), the University of Otago and the Otago Medical Research Foundation. 

Other Activities:
Fogarty International Postdoctoral Fellow 1972-74 (University of Texas, University of Illinois). Study leave: INRA, Jouy-en-Josas, France, 1981; AFRC Food Research Institute, Reading, UK, 1988. Principal undergraduate teaching duties: Medical microbiology, Stage 2, 3, 4 students (BSc, BMLSc); Bacterial structure and function, Stage 2 (BSc, BMLSc). Research group: Normal microflora of mammals. One junior research fellow, one technician, three PhD students, one MSc student, two BSc Hons Stage 4 students, one BMLSc stage 4 student, one part time laboratory assistant. Publications 76. The textbook "Normal Microflora" is due to be published by Chapman and Hall, London in 1994. 

Gerald was promoted to Professor in 1996.

A promotional video about the Department made in 1996, narrated by Gerald Tannock

Gallery of lab photos

Gerald was professional about everything he did. His lectures were very popular because they were like staged performances -- for which he won teaching awards. His lab was always orderly and well managed with labels on the cupboards and everything in its place. He was well-mannered and well-dressed and never failed to greet you with a smile -- the ultimate gentleman scientist.

Fast Forward to 2016

It is estimated that there are 10,000 times more bacterial cells in the human colon (also known as the large intestine or large bowel) than there are humans on Earth. Comprising tens of trillions of micro-organisms, including more  than 3 million genes (150 times more than human genes), this colony on average weighs about 1.5kg, of which about a third is common to most people; the remainder is specific to each individual. Although they can lead to infection should they escape from the colon, many of these organisms are essential for our health.

Maintaining gut health has implications in neurological and neuropsychiatric disorders, including multiple sclerosis, autistic spectrum disorders, and Parkinson’s disease; connections between age-related gut changes and Alzheimer’s disease have also been made, and various animal studies have shown that manipulating the gut microbiota in some way can produce behaviours related to anxiety and depression.

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