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Department of Microbiology & Immunology Programme
Seminar Series … March 2015
Day / Date / Time:
Tuesday
31st March 2015
12pm - 1pm
Probiotic Regulation of Host Physiology
Associate Professor Lee Yuan Kun
Department of Microbiology,
Yong Loo Lin School of Medicine,
National University Health System,
National University of Singapore
Venue:
National University of
Singapore (NUS),
Department of
Microbiology,
Seminar Room @
5 Science Drive 2,
Blk MD4A, Level 2,
Singapore 117545
Convener:
Prof Nicholas Gascoigne
Abstract
Gastrointestinal (GI) microbes play important roles in the health and disease of the host.
There are many documented evidences which demonstrated that disturbance of intestinal
microbiota is linked to the risk of developing infectious, inflammatory and allergic
diseases. Human intestine is home for a complex consortium of 1013-1014 microbial cells.
Interactions between the intestinal microbes, pathogens and host lead to exclusion of toxins
(mycotoxins) and pathogens (colonization resistance), interference in disease progression
as demonstrated in the prevention of oral infection, dental caries, diarrhoeas (Antibiotic
Associated Diarrhoea, Travellers’ Diarrhoea and Rotavirus Diarrhoea), postoperative
infection, respiratory infection and certain cancers. The group of beneficial intestinal
microbes termed probiotics alter intestinal epithelial cell tight junction and immunological
functions, via Toll-like receptor mediated cytokines. Probiotics are also involved in the
digestion and transformation of dietary components, and energy metabolism. They
promote intestinal peristaltic movement and modulate GI microbiota through competition
for GI surface receptors and production of antimicrobial substances. Lately, laboratory
and clinical studies demonstrated gut-brain axis communication and intestinal microbial
(both pathogens and probiotics) modulation of host psycho-neuroimmunological
functions, in relation to depression, anxiety and memory dysfunction, via regulation of
hormone production and neurotransmission. These open up many possibilities for
moderating intestinal microbiota as an approach in disease prevention and treatment.
Composition and succession of the intestinal microbiota of people in various geographical
regions have been characterized. Such perspective studies provide markers for the stage
of health and positive guidance for microbial colonization through interference. Diet is a
major factor in determining intestinal microbiota profile, health and diseases.
Selected Publications
ALL ARE WELCOME
1. J Nakayama, K Watanabe, JH Jiang, K Matsuda, SH Chao, P Haryono, O La-ongkham, MA
Sarwoko, IN Sujaya, L Zhao, KT Chen, YP Chen, HH Chiu, T Hidaka, NX Huang, C
Kiyohara, T Kurakawa, N Sakamoto, K Sonomoto, K Tashiro, H Tsuji, MJ Chen, V
Leelavatcharamas, CC Liao, S Nitisinprasert, ES Rahayu, FZ Ren, YC Tsai, YK Lee (2015)
Diversity in gut bacterial community of school-age children in Asia. Scientific Reports 5 :
8397 | DOI: 10.1038/srep08397
2. Wang SG, Hibberd ML, Pettersson S, Lee YK (2014) Enterococcus faecalis from healthy
infants modulates inflammation through MAPK signalling pathways. PLOS ONE 9(5):
e97523. doi:10.1371/journal.pone.0097523.
Visit our website @
www.med.nus.edu.sg/mbio
for more upcoming seminars
3. Kandasamy M, Bay BH, Lee YK, Mahendran R (2011) Lactobacilli secreting a tumor
antigen and IL15 activates neutrophils and dendritic cells and generates cytotoxic T
lymphocytes against cancer cells. Cellular Immunology 271: 89-96.
4. SEOW, S W, N B R JUWITA, B H Bay, Y K Lee and R Mahendran (2008) Expression of
chemokine/cytokine genes and immune cell recruitment following the instillation of
Mycobacterium bovis, bacillus Calmette-Guérin or Lactobacillus rhamnosus strain GG in
the healthy murine bladder. Immunology, 124: 419-427.
5. Lee, Y K, CY Lim, WL Teng, AC Ouwehand, FM Tuomola and S Salminen (2000)
Quantitative approach in the study of adhesion of lactic acid bacteria to intestinal cells and
their competition with enterobacteria. Applied and Environmental Microbiology, 66 (2000):
3692-3697.