Day 2 :
Keynote Forum
Olga Genilloud
Fundacion Medina, Spain
Keynote: Exploiting microbial sources to deliver novel bioactive natural products
Time : 10:15-11:00
Biography:
Olga Genniloud, Scientific Director at Medina, a research center focused on the discovery of novel bioactive NPs with one of the richest and most diverse NPs collections that are at the origin of our collaborative drug discovery research programs.
Abstract:
Microbial natural products (NPs) have been one of the most prolific sources of new leads for the discovery of novel drugs to respond to unmet needs in infectious diseases, cancer and other therapeutical areas, with a large number of molecules and analogs still today in clinical practice. NPs present a unique chemical space and architectural complexity, and their potency and selectivity is the result of an extended evolutionary selection to create biologically active molecules with the required properties to interact and potentially inhibit bacterial targets.
NPs continue to play a key role in the discovery of new molecules to fill the chemotherapeutic arsenal and in the last years much attention has been given to marine sources and other less explored ecological niches such as lichens and plant associations which have proven to be an untapped rich source of new microbial diversity and novel NPs. Microbial genome mining and cutting edge analytical tools have become essential tools in any modern NPs drug discovery paradigm. These new platforms are allowing to focus NPs research on highly qualified microbial isolates, to assess their biosynthetic potential and address the discovery of new secondary metabolites using both culture-based approaches as well as heterologous-based expression systems to unlock new cryptic biosynthetic pathways.
Keynote Forum
Yong Ho Park
Seoul National University, South Korea
Keynote: One health approaches to zoonotic diseases: MERS, HPAI and AMR
Time : 09:30-10:15
Biography:
Abstract:
Keynote Forum
Maulin P Shah
Enviro Technology Limited, India
Keynote: Title:Exploitation of Enterobacter spp. in microbial degradation of acrylamide: An environmental bioremedial approach
Time : 11:20-12:05
Biography:
Maulin P. Shah, currently Chief Scientist & Head – Industrial Waste Water Research Lab, Division of Applied and Environmental Microbiology Lab at Enviro Technology Ltd., Ankleshwar, Gujarat, India. He is a Microbial Biotechnologist with diverse research interest. A group of research scholars is working under his guidance on the areas ranging from Applied Microbiology, Environmental Biotechnology, Bioremediation, and Industrial Liquid Waste Management to solid state fermentation. His work has been focused to assess the impact of industrial pollution on microbial diversity of wastewater following cultivation dependant and cultivation independent analysis. His major work involves isolation, screening, identification and Genetic Engineering of high impact of Microbes for the degradation of hazardous materials He is an active Editorial Board Member in 140 highly reputed Journal’s in the field of Environmental & Biological Sciences
Abstract:
A widespread use of acrylamide, probably a neurotoxicant and carcinogen, in various industrial processes has led to environmental contamination. Fortunately, some microorganisms are able to derive energy from acrylamide. In the present work, we reported the isolation and characterization of a novel acrylamide-degrading bacterium from domestic wastewater in Chonburi, Thailand. The strain grew well in the presence of acrylamide as 0.5% (W/V), at pH 6.0 to 9.0 and 25°C. Identification based on biochemical characteristics and 16S rRNA gene sequence identified the strain as Enterobacter spp. Degradation of acrylamide to acrylic acid started in the late logarithmic growth phase as a biomass-dependent pattern. Specificity of cell-free supernatant towards amides completely degraded butyramide and urea and 86% of lactamide. Moderate degradation took place in other amides with that by formamide > benzamide >acetamide > cyanoacetamide > propionamide. No degradation was detected in the reactions of N,N-methylene bisacrylamide, sodium azide, thioacetamide, and iodoacetamide. These results highlighted the potential of this bacterium in the cleanup of acrylamide/amide in the environment.
- Applied Microbiology | Industrial Microbiology | Veterinary Microbiology S
Session Introduction
Learn-Han Lee
Monash University, Malaysia
Title: The cancer chemopreventive potential of novel Streptomyces strains derived from mangrove forest in Malaysia
Time : 12:35 -13:05
Biography:
Learn-Han Lee, (Ph.D in Molecular Biology), male, a senior lecturer of molecular biology, PI of Novel Bacteria and Drug Discovery Research Group, School of Pharmacy, Monash University Malaysia. Dr. Lee was awarded the prestigious title of Chartered Biologist (CBiol) from the Royal Society of Biology, UK in 2017. Currently, his researches focus on the study of novel bacteria discovery and bio-prospecting of secondary metabolites with anticancer properties. He is the lifetime member of Bergey’s International Society for Microbial Systematics (BISMiS) and a Member of Royal Society of Biology (MRSB, UK). Furthermore he is an associate editor for Frontiers in Microbiology (IF: 4.165) and Frontiers in Pharmacology (IF: 4.418). Now he has 2 patents, and published 2 academic books, 3 book chapters and 75 international articles, with a total citation of 877 and H-index of 17 (Google scholar citation). He has received 19 items of awards from various reputable institutions.
Abstract:
The global burden of cancer continues to surge, mainly due to aging and growth of the world population, on top of cancer-causing lifestyle behaviours including smoking, obesity and lack of exercise. The financial and economic impacts of cancer on health care, patients and society have urged the search for more effective and potent drug to combat and prevent its occurrence. Microorganisms have been an important source of bioactive natural compounds as they provide a sustainable production of bioactive metabolites with a reasonable cost. Members of family Actinobacteria, especially the genus Streptomyces have demonstrated exemplary performance in synthesizing bioactive metabolites. In fact, several chemotherapy drugs in use, e.g. doxorubicin and actinomycin were discovered from Streptomyces. Thus, it is important to continue the search for novel streptomycetes-derived bioactive compounds against cancer cells. Four novel Streptomyces species were identified from the poorly explored mangrove sediment (East Coast, Peninsular Malaysia) using polyphasic approach. These strains (designated as MUSC 26T, MUSC 136T, MUSC 149T and MUSC 164T) have demonstrated significant antioxidant activity and screened for cytotoxic activity against several human cancer cell lines (DU145, CaSki, A549, MCF-7, HT-29, HCT-116, Caco2 and SW480). Among the four strains, MUSC 136T displayed highest cytotoxic activity against colon cancer cell line HCT-116, killing more than half of them at 400 µg/mL, which probably mediated through altering p53 protein and intracellular glutathione levels. Meanwhile, MUSC 164T demonstrated similar cytotoxic effect against HCT-116 with lowest cell survival recorded at 58.2 ± 5.1% after treated with 400 µg/mL of the extract. A deeper investigation into the genome of these streptomycetes revealed potential production of interesting bioactive compounds, which include siderophore desferroxamine. Altogether, these findings suggested that the exploration of new taxa from underexplored area is a good strategy to discover useful bioactive compounds
Juhee Ahn
Kangwon National University, Republic of Korea
Title: Comparative assessment of ï¢-lactamases produced by multidrug resistant bacteria
Time : 13:50 -14:20
Biography:
Juhee Ahn is interested in the microbial pathogenesis, including the mechanistic studies of antibiotic resistance, bacterial infection, and bacteriophage control. He received his Ph.D. degree majoring in Food Microbiology at the University of Missouri, Columbia, USA and continued his work as a post-doctoral research assistant in Food Microbiology Lab at the University of Missouri (2003-2004) and Food Safety Engineering Lab at the Ohio State University (2004-2006). He was a visiting scholar at the University of Maryland (2012-2013) as well as Zhejiang University (2016-2017). Currently, he is a professor at the department of Medical Biomaterials Engineering, Kangwon National University. South Korea.
Abstract:
The multidrug resistance in K. pneumoniae is primarily mediated by the production of different classes of b-lactamases. The relationship between b-lactamase production and resistance phenotype is essential to understand the resistance mechanisms in K. pneumoniae. However, there is still a lack of information on the phenotypic and genotypic antibiotic resistance profiles in association with the classes of b-lactamases in K. pneumoniae. Therefore, the aim of this study was to evaluate the antibiotic susceptibility and b-lactamase production in ciprofloxacin-induced and clinically-isolated antibiotic-resistant K. pneumoniae strains, based on the interaction between b-lactamases and b-lactamase inhibitors. The antibiotic susceptibility and β-lactamase activity of K. pneumoniae strains, including antibiotic-sensitive K. pneumoniae (KPWT), ciprofloxacin-induced resistant K. pneumoniae (KPCIP), and clinically isolated K. pneumoniae strains (KPCI237, KPCI263, and KPCI272), were determined in the absence and presence of β-lactamase inhibitors (BLI 489, sulbactam, clavulanate, and tazobactam). All strains were highly resistant to ampicillin in the absence of b-lactamase inhibitors (MIC≥512 mg mL-1). In the presence of clavulanate, the MICs of ampicillin and piperacillin against KPWT were decreased by >64-fold and 4-fold, respectively. The resistance of KPCI263 to cefotaxime, ceftazidime, ceftriaxone, and piperacillin were increased in the presence of BLI-489. The antibiotic susceptibilities KPCI237 to b-lactams were not noticeably changed in the presence of β-lactamase inhibitors (clavulanate, sulbactam, and tazobactam). KPWT, KPCIP and KPCI272 were positive for blaSHV, blaAmpC, and blaFOX/MOX, KPCI237 for blaSHV and blaAmpC, and KPCI263 for blaSHV and blaOXA-48. The antibiotic susceptibility corresponded well with the results obtained from dual disc diffusion assay, which was in good agreement with the b-lactamase production. The results provide useful information for understanding the resistance phenotypes in association with b-lactamase production.
Shwu-Jen Liaw
National Taiwan University, Taiwan
Title: The effect of RpoN on swarming in uropathogenic Proteus mirabilis
Time : 14:20 -14:50
Biography:
Shwu-Jen Liaw has major research interests in investigating the molecular mechanisms of bacterial pathogenesis and drug resistance. She has discovered several genes and pathways that are associated with swarming and virulence of Proteus mirabilis, a pathogen causing urinary tract infections.
Abstract:
Proteus mirabilis is an important pathogen of the urinary tract, especially in patients with indwelling urinary catheters. Since catheter-associated urinary tract infection is a major health concern due to the complications and recurrence, researches directed at understanding the pathogenesis are warranted. P. mirabilis pathogenesis is closely coupled to swarming. Previously, we found a two component system, QseEF, is involved in the swarming ability and a sRNA GlmY is under the control of QseEF in P. mirabilis. Many studies have shown that the RpoN, a bacterial alternative sigma factor 54, involved in the transcription of nitrogen-related genes, is also associated with motility in pathogenic bacteria. Thus we investigated the role of RpoN in swarming motility in P. mirabilis. Bioinformatic analysis revealed an RpoN binding site located on the glmY-qseEF promoter region in P. mirabilis. We constructed rpoN mutant and performed swarming assay in wild-type and rpoN mutant. We found that the loss of rpoN inhibited swarming motility. The reporter assay and the real-time RT-PCR demonstrated transcription of GlmY is modulated by RpoN. By the real-time RT-PCR, we then showed GlmY modulates mRNA expression of master flagellar regulator flhDC and chemotaxis protein cheA, which corresponds with the finding of swarming defect in glmY mutant. In addition, the real-time RT-PCR data indicated RpoN modulates mRNA expression of glnA, a gene encoding glutamine synthetase (GlnA) essential for synthesis of a swarming signal (glutamine) in P. mirabilis. These data reveal the swarming regulatory network of RpoN, QseEGF, GlmY, FlhDC, CheA and GlnA in P. mirabilis. Altogether, this is the first report about the role of P. mirabilis RpoN in swarming motility and its regulatory mechanism.
Muinat O Kazeem
UPM, Malaysia
Title: Partitioning and purification of carboxymethyl cellulase from in aqueous biphasic system extraction
Time : 14:50 -15:20
Biography:
Muinat Olanike Kazeem has expertise in bioprocessing of lignocellulose for biosugars and value added products through catalysis of enzymatic saccharification. Her research involving cellulolytic enzymes majorly from thermophilic bacteria sources employ fermentation and aqueous biphasic system extraction recovery for efficient performance. Her experience in teaching and research in the University of Ilorin, Nigeria and University Putra Malaysia in the field of industrial microbiology and environmental biotechnology is of great contribution to the science. Future research will explore biohydrogen, biocompost, bioethanol and other industrial enzymes
Abstract:
Statement of problem: Caboxymethyl cellulase (CMC) is one of the significant enzyme in biofuel, textile, paper, brewing and animal feed industries, because of its ability to catalyze enzymatic hydrolysis cellulosic material into simple sugars. However, the downstream processing of CMCase from fermentation broth involves tedious conventional chromatographic steps which is time consuming and complicated. Researchers have reported different methods such as gel filtration and ion-exchange chromatography, ammonium sulphate fractionation and chromatography on DEAE-sephadex A-50 and Sephadex G-100 80 and ultrafiltration. However, application in large scale becomes difficult due to high cost, low productivity and multiple purification steps involved; thus, a cost effective strategy for recovery of CMCase is in demand. One possible method to overcome this challenge is aqueous biphasic system extraction (ABSE). The purpose of this study is to examine the effectiveness of applying ABSE involving polyethylene glycol/salt for the partitioning behavior and recovery of CMCase produced from thermophilic Bacillus licheniformis 2D55 fermentation broth. Methodology: The effect of ABS variables of type of salt, PEG molecular weight, crude loading, pH and additional sodium chloride (NaCl) on partitioning behavior of CMCase were investigated. Findings: A 14 % (w/w) crude load , 1 % NaCl, pH 7.0 produced a CMCase recovery yield (Y) of 88.63 %, a partition coefficient (K) of 0.21 and purification factor (PFT) of 10.3 from the bottom phase of PEG 8000/sodium citrate ABSE. The hydrophobicity nature of the CMCase surface enhanced the partition and extraction of the CMCase to the salt rich bottom sodium citrate phase. Likewise, impurities undesired proteins were separated to the PEG 8000 rich top phase. The effectiveness of the recovery was confirmed by SDS-PAGE analysis. The study suggest that ABSE may be a potential strategy for industrial purification of CMCase form fermentation broth
Shih-Yen Chen
Chang Gung University, Taiwan
Title: Virological and Clinical Characteristics and Viral Shedding of Children with Norovirus Gastroenteritis
Time : 15:20 -15:50
Biography:
Shih-Yen Chen is currently an attending physician in the Department of Pediatrics, Chang Gung Children’s Hospital and Chang Gung University, Taoyuan, Taiwan. He received his Doctor of Medicine degree from Taipei Medical College, and Doctor of Philosophy degree from Chang Gung University College of Medicine.
Abstract:
Norovirus (NoV) is an emerging enteric pathogen and being recognized as a global health burden as leading viral cause of outbreaks of gastroenteritis worldwide. The rapid transmission of NoV via person-to-person contact makes infection control difficult. Our study is to establish the standardization of viral load in NoV AGE to investigate and correlate clinical features, disease characteristics, viral shedding and transmissibility.
Fecal specimens from recruited children in Chang Gung Children’s Hospital under diagnosis of norovirus gastroenteritis examined by RT-PCR and their clinical features of hospitalization were characterized. Norovirus real time RT-PCR assay with viral copy numbers ((log)/g feces) calculation as viral load were performed. Fisher exact test was used to determine differences between clinical features. The viral load increasing varied from the 3rd day to the 8th day forming an unsmooth plateau feature without peaking. After the 8 th day, the viral load declined and sheded at the 15 th day after illness onset. In regards to correlate viral load with clinical manifestations, we found there is a longer shedding period in patients in 17 febrile patients (16.3 days after disease onset) than in 21 afebrile ones (12.7 days after disease onset) (P=0.03) also a significantly longer shedding period of patients infected by GII.4 Sydney strain (17.6 days after illness onset) then by non- GII.4 Sydney(12.3 days after disease onset) strain norovirus (P <0.01).
In conclusion, the copy numbers based method viral load evaluation provide a more specific and precise way for assessment noroviruses detection, viral shedding, transmissibility, and even clinical correlation.
Sang Ho Choi
Seoul national university, Seoul
Title: Control rather than eradication of pathogenic bacteria: Quorum sensing of Vibrio vulnificus
Time : 16:40 -17:10
Biography:
Sang Ho Choi works at National Research Laboratory of Molecular Microbiology and Toxicology. He belongs to department of Food Science and Biotechnology, Seoul National University
Abstract:
Bacterial pathogenicity involves numerous virulence factors required for successful survival in host environments as well as invasion and destruction of host tissues. The pathogenic marine bacterium Vibrio vulnificus is a causative agent of food-borne diseases such as gastroenteritis and life-threatening septicemia. It has been reported that expression of V. vulnificus virulence factors is well-coordinated and regulated by sophisticated mechanisms consisting of many global regulatory proteins. Among them, SmcR, a quorum-sensing master regulator and homologue of V. harveyi LuxR, has been identified and found to play a critical role in the regulation of the V. vulnificus virulence factors. The crystal structure of SmcR reveals that SmcR belongs to the TetR family protein possessing putative ligand-binding pockets. To identify the small molecules which bind to and inhibit SmcR, chemical libraries were screened and an SmcR inhibitor exhibiting the most effective SmcR-inhibition activity was selected and named QStatin. The lack of reduction of intracellular levels of SmcR in QStatin-treated V. vulnificus suggested direct binding of the chemical to SmcR. Isothermal titration calorimetric (ITC) and crystallization analyses confirmed the chemical binding of QStatin into the pockets of SmcR. Although no big conformational changes were observed in the crystal structure, binding of QStatin reduced the DNA binding affinity of SmcR, and thereby changed the expressions of SmcR regulon similar to those of SmcR mutants. Accordingly, QStatin significantly inhibits expression of V. vulnificus virulence genes, leading to the decreased mortality of a brine shrimp infected with V. vulnificus. Most interestingly, QStatin attenuates pathogenicity of V. vulnificus, but does not inhibit growth itself at all, unlike existing antibiotics. Consequently, the combined results indicate that QStatin could be a novel lead compound to control QS-mediated pathogenesis of V. vulnificus with the lowest possibility of the appearance of resistant strains.
- Molecular Microbiology | Cellular Microbiology | Antibiotics and Chemotherapy Clinical and Diagnostic Microbiology | Food and Beverage Microbiology
Session Introduction
Min Suk Song
Chungbuk National University, South Korea
Title: Rapid detection of emerging infectious diseases using real-time colorimetric Reverse Transcriptional Loop-mediated Isothermal Amplification (RT-LAMP)
Time : 13:50 -14:20
Biography:
Min-Suk Song completed his undergraduate degree, Major in Biology, MSc and PhD degree in Virology in Chungbuk National University College of Medicine. He formerly worked as a Post-Doctoral Research Fellow at St. Jude Children’s Research Hospital. He is currently an Assistant Professor at Chungbuk National University College of Medicine and Research Institute since 2014. His published papers were particularly in the areas of Virology which include pathogenicity, molecular studies and diagnosis of influenza viruses. Recently, he has expanded his research on other viruses such as Enterovirus and MERS-coV. His other research interest includes vaccines and antiviral resistance. His current and future studies aim to contribute in protecting and improving people's health.
Abstract:
Recent increased cases of human infection with emerging infectious viruses such as avian influenza virus (AIV), Middle East Respiratory Syndrome-Corona Virus (MERS-CoV), and Severe Fever with Thrombocytopenia Syndrome virus (SFTSV) are concerns of public health. We developed a simple and rapid detection system using Reverse Transcriptional Loop-mediated Isothermal Amplification (RT-LAMP) method for multiple emerging infectious viruses including MERS-CoV, SFTSV, and multiple influenza viruses infecting human (type B, H1N1, H3N2, H5N1, H5N6, H5N8, and H7N9). In addition, for more feasible application, the RT-LAMP method was optimized with real-time colorimetric visualization and portable diagnostic platform such as pocket warmer. The RT-LAMP detection system performed high sensitivity that can detect up to 0.1 infectious viral genome copies of the viruses within 60 min compared to the conventional RT-PCR based methods which usually take more than 120 min. Moreover, the test has no cross-reactivity with other human infectious viruses including JEV, Dengue, Enterovirus, Zika virus, human coronavirus 229E (229E), human Metapneumovirus (hMPV), human Respiratory Syncytial Virus (hRSV), and other subtypes of influenza viruses including H2, H4, H6, H9, H10, H11, and H12. Thus, this study suggests that our diagnostic assay may provide a rapid, sensitive, cost-effective, multiplex detection system for emerging infectious viruses that can play a crucial role in control of virus outbreak and contribute to the field diagnosis in resource-limited field settings.
Takashi Horiuchi
Tokai University, Japan
Title: Double rolling circle replication (DRCR): a mode of amplification of oncogene as well as drug-resistant genes and replication of HSV and chloroplast DNA
Time : 14:50 -15:20
Biography:
Takashi Horiuchim his areas of research interest is Genome Dynamics, especially the physiological role in DNA replication fork blocking events in E. coli and S. cerevisiae, successful conversion from the circular genome of E. coli to linear, molecular mechanism of gene amplification of rDNA in yeast and oncogene (drug-resistant gene) in higher eukaryotes, and molecular mechanism of DRCR (Double Rolling Circular Replication) in Herpes Simplex Virus (HSV) and Chloroplast DNA. Dr. Horiuchi got Kihara Prize (2007) from Japan Society of Genetics for “Identification and characterization of DNA replication fork blocking event
Abstract:
It is well established that eukaryote nuclear chromosomes are duplicated from multiple origins of replication. It remains a mystery, however, how genomes of some viruses, such as HSV (Herpes simplex virus) and Baculovirus, or chroloplasts, are replicated. We found recently that (i) double rolling circle replication (DRCR), originally found responsible for replication of yeast 2 micron plasmid DNA, can lead to amplification of oncogenes as well as drug resistance genes, and (ii) that DRCR is highly recombinogenic. In addition, we will present our model, based on these findings, that DRCR is involved in DNA replication of HSV-1, chloroplasts and some mitochondria. The model could explain how DRCR contributes to replication-recombination coupling of HSV, and also how it promote amplicon shortening during gene amplification. HO induced
Chang-Hwa Song
Chungnam National University, Republic of Korea
Title: Endoplasmic reticulum stress-induced Calreticulin suppresses the growth of mycobacteria in macrophages
Time : 14:20 -14:50
Biography:
Chang-Hwa Song has his expertise in evaluation and passion in improving the health and wellbeing. His work has been focused on the understanding the pathogenesis of tuberculosis based on host immune responses. He has developed his theory for interaction between mycobacteria and host macrophages after years of experience in research, evaluation, teaching and administration in medical school. He published many scientific papers related to endoplasmic reticulum stress response during mycobacterial infection. This approach is responsive to all scientists of tuberculosis and has provided a different way of research
Abstract:
Calreticulin (CRT) is an endoplasmic reticulum luminal calcium-binding chaperone protein. It is associated with the regulation of calcium homeostasis, protein folding and various cellular functions. Many diseases are associated with ER stress including tuberculosis. In this study, we examined the role of Mycobacterium tuberculosis (Mtb) induced ER stress in induction of CRT expression on macrophages. We found that Mtb infection induces CRT production by macrophages and that CRT levels are correlated with the degree of apoptosis. A significant increase in CRT translocation from the cytosol to the plasma membrane after 24 h of infection suggested the importance of CRT localization in the induction of apoptosis during Mtb infection. During the mycobacterial infection, production of reactive oxygen species (ROS) plays crucial roles in induction of ER stress or enhancement of proinflammatory cytokines. In the present study, we showed that pretreatment with a reactive oxygen species scavenger decreased Mtb-induced CRT expression, leading to the reduction of CHOP and caspase-3 activation. The intracellular survival of Mtb was significantly higher in macrophages transfected with a CRT-specific small interfering RNA than in control cells. The key role of CRT in inducing apoptosis included its interaction with CXCR1 and TNFR1 in Mtb-infected macrophages. The CRT/CXCR1/TNFR1 complex was shown to induce the extrinsic apoptotic pathway during Mtb infection. Collectively, our results suggest that CRT is critical for the intracellular survival of Mtb, via ER-stress-induced apoptosis
Nguyen V.U
Ghent University, Belgium
Title: Prevention of F18+ Escherichia coli infection in weaning pigs using polyvalent receptor analogues
Time : 16:10 -16:40
Biography:
Nguyen completed his PhD in Ghent University about the complexity of the intestinal receptors of Enterotoxigenic E. coli in pigs and the immune response against these pathogens. Nguyen explores the gut and studies the genomic and proteomic of pig gut to search for biomarkers to be used in breeding and prophylaxis.
Abstract:
Diseases, such as diarrhea and/or edema disease, frequently can occur in pigs shortly after weaning pigs. Main causes are enterotoxigenic (ETEC) or verotoxigenic Escherichia coli (VTEC) expressing F18 fimbriae. Infections lead to considerable economic losses due to mortality, decreased growth rate and cost of medication. F18+ E. coli use their fimbriae to attach to specific receptors on the pig intestinal epithelium and produce enterotoxins (LT, STa and/or STb) and/or verotoxins (VTx2e) leading to diarrhea or edema disease, respectively. Antibiotics are routinely used to combat these infections, but due to the emergence of antimicrobial resistance, there is an urgent need for alternatives. The lab of Immunology discovered that F18+ E. coli specifically interacts with blood group ABH determinants on type 1 core chains (Coddens et al., 2009; PCT/EP2009/062699; INHIBITORS OF F18+ E COLI BINDING). Based on this fundamental discovery, we developed an anti-adhesive therapy. A high dose of the monomeric compounds (e.g. A6-1) could inhibit in vitro the binding of F18+ E. coli to porcine intestinal villi. Multimerization of the monomeric receptor structure could significantly enhance efficacy. The multimer was able to decrease binding in vitro with 66 % at a more than 2,500 times lower concentration than the monomeric sugar. In small intestinal perfused intestinal segments, a 10 times higher dosage than in vitro was able to prevent fluid loss (a measure of diarrhoea) due to inoculation with F18+ STa+STb+ ETEC. In an in vivo experiment, this dose in feed significantly reduced the duration and height of the faecal excretion of pigs inoculated with an F18+ VTEC strain.
- Special Session
Session Introduction
Hiroshi Ohrui
Yokohama University of Pharmacy, Japan
Title: An Extremely Excellent Anti-HIV Active Modified Nucleoside, EFdA Focused on its Design
Time : 12:05 -13:05
Biography:
Hiroshi Ohrui received Ph.D. degree (1971) from The University of Tokyo. He Joined RIKEN (1966) and moved to Tokyo University (1981). He moved to Yokohama University of Pharmacy (2006). He worked for Dr. J. J. Fox at Sloan- Kettering Institute for Cancer Research (1972-1973) and Dr. J. G. Moffatt at Syntex Research (1973-1974). He received several awards including Inoue Prize for Science (2001), Japan Prize for Agricultural Sciences (2004), The Japan Society for Analytical Chemistry Award (2004), and Japan Academy Prize (2010). His research interests cover organic synthesis, chemical biology and chiral discrimination.
Abstract:
4’-C-Ethynyl-2-fluoro-2’-deoxyadenosine (EFdA) has attracted much attention due to its extremely excellent anti-HIV properties (1. prevent the emergence of resistant HIV mutants, 2. over 400 times more active than AZT and several orders of magnitude more active than the other clinical reverse-transcriptase inhibitor 2’, 3’-dideoxy-nucleoside drugs, 3. very low toxic, 4. long acting, 5. possible use for prophylaxis, and so on).
EFdA is now under clinical trials as MK-8591 by Merck & Co..
For the design of the modified nucleoside which could solve the problems that the clinical drugs have (1. emergence of drug-resistant HIV mutants, 2. adverse effect by drugs, 3. necessity of taking quite a few amount of drugs), I have proposed the following working hypotheses . They are (1) the way to prevent the emergence of drug-resistant HIV mutants, (2) the way to decrease the toxicity of modified nucleosides, (3) the way to provide the modified nucleoside with stability to both enzymatic and acidic glycolysis for long acting.
4’-C-substituted-2’-deoxy nucleoside was designed to meet the hypotheses (1), (3), and the two-site modification was performed to meet the hypothesis (2).
The details of the hypotheses and the reasons of the design of 4’-C-substituted-2’-deoxy nucleoside will be presented.
To prevent the deamination of adenine base, fluorine atom was introduced at the 2-position of adenine base.
Finally, EFdA which is modified at the two position(2 and 4’) of the physiologic 2’-deoxyadenosine and has extremely excellent anti-HIV properties has been successfully developed.