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 26^T, MUSC 136^T, MUSC 149^T and MUSC 164^T) 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 136^T 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 164^T 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

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 (KP^WT), ciprofloxacin-induced resistant K. pneumoniae (KP^CIP), and clinically isolated K. pneumoniae strains (KP^CI237, KP^CI263, and KP^CI272), 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 KP^WT were decreased by >64-fold and 4-fold, respectively. The resistance of KP^CI263 to cefotaxime, ceftazidime, ceftriaxone, and piperacillin were increased in the presence of BLI-489. The antibiotic susceptibilities KP^CI237 to b-lactams were not noticeably changed in the presence of β-lactamase inhibitors (clavulanate, sulbactam, and tazobactam). KP^WT, KP^CIP and KP^CI272 were positive for bla_SHV, bla_AmpC, and bla_FOX/MOX, KP^CI237 for bla_SHV and bla_AmpC, and KP^CI263 for bla_SHV and bla_OXA-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.

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.

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 (P_FT) 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

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 3^rd day to the 8^th 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.

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.