Day 1 :
National University of Singapore, Singapore
Keynote: Structure of AcrH-AopB chaperone-translocator complex reveals a role for membrane hairpins in type III secretion system translocon assembly
Time : 10:00-10:45
Mok Yu-Keungn has his expertise in determining the structural/functional relationship of protein involved in human diseases using both Nuclear Magnetic Resonance (NMR) and X-ray crystallography.
Type III secretion systems (T3SSs) are adopted by pathogenic bacteria for the transport of effector proteins into host cells through the translocon pore comprised of major and minor translocator proteins. Both translocators require a dedicated chaperone for solubility. Despite tremendous efforts in the past, structural information regarding the chaperone:translocator complex and the topology of the translocon pore have remained elusive. Here, we report the crystal structure of the major translocator, AopB from Aeromonas hydrophila AH-1 in complex with its chaperone, AcrH. Overall, the structure revealed unique interactions between the various interfaces of AopB and AcrH with the N-terminal molecular anchor of AopB crossing into the N-terminal arm of AcrH. AopB adopts a novel fold and its transmembrane regions form two pairs of helical hairpins. From these structural studies and associated cellular assays, we deduced the topology of the assembled T3SS translocon with both termini remain extracellular after membrane insertion
Director Professor and Head of Microbiology
Keynote: Cartridge based nucleic acid amplification test (CBNAAT): A new tool in diagnosis of osteoarticular tuberculosis
Time : 10:45-11:30
Baveja C P is the Director Professor and Head of Microbiology at Maulana Azad Medical College in New Delhi. He was awarded an International Fellowship at Royal Postgraduate Medical School and Hammersmith Hospital in UK. He has also conducted research work on Polymerase Chain Reaction at London School of Hygiene and Tropical Medicine. He has been teaching Microbiology to medical undergraduates for past three decades. He was honored with the Best Medical Educationist award in 2000. He has been mentoring postgraduates for the last 25 years. He has been involved in research work with particular emphasis on diagnosis of tuberculosis. He has supervised a number of PhD students with research work on tuberculosis. He is also the Nodal Officer and In-Charge for State Reference Laboratory for HIV testing.
Statement of the Problem: Osteoarticular tuberculosis is an important cause of mortality and morbidity in developing countries because of high prevalence. Microbiological diagnosis of osteoarticular tuberculosis is difficult since it is mostly a paucibacillary disease and the culture method takes long time for its diagnosis. The purpose of this study was to evaluate the results of CBNAAT over conventional methods for diagnosis of osteoarticular tuberculosis.
Methodology & Theoretical Orientation: Clinically suspected cases of osteoarticular tuberculosis having an abscess were enrolled in the study. A total of 45 samples were studied. Five milliliter of aspirate/Pus was obtained from each case and processed as follows: (1) Direct microscopy by Ziehl-Neelsen (ZN) Staining, (2) Culture on Lowenstein-Jensen (LJ) medium, (3) Culture in Mycobacteria Growth Indicator Tube (MGIT) and (4) CBNAAT analysis.
Findings: Out of the 45 samples tested, 19 (42.22%) were positive for Mycobacterium tuberculosis (MTB) by CBNAAT, 11 (24.44%) showed growth of Mycobacterium tuberculosis in MGIT, 9 (20.00%) showed growth of Mycobacterium tuberculosis on Lowenstein-Jensen medium and only 4 (8.89%) showed presence of Acid Fast bacilli on Ziehl-Neelsen staining. Of the 19 samples that were positive for MTB using CBNAAT, 3 (15.79%) samples were also detected as Rifampicin resistant.
Conclusion & Significance: The foremost benefit of CBNAAT for diagnosis of osteoarticular tuberculosis was that it was able to detect additional 10 cases as compared to LJ culture. The test results were available within 1 day, greatly decreasing the turnaround time. Through this study CBNAAT was found to have great potential for diagnosis of osteoarticular tuberculosis earlier than the conventional methods.
- Infectious Diseases | Parasitology | Bacterial Diseases | Bacterial Clinical studies | Bacterial Pathogenesis
Location: Seletar Foyer
National Institutes of Health in Bethesda USA.
Time : 11:50-12:20
Ian A Myles works for the National Institutes of Health in Bethesda in USA. His research focus is on the therapeutic use of live bacteria to treat atopic dermatitis. He has also published on the use of cell lysate therapy and various aspects of immuno-nutrition. He is also an Officer with the US Public Health Service Commissioned Corps, assisting in the vaccination trials for Ebola and more recently Zika virus. Overall his work examines how early environmental and nutritional exposures impact the development of immunity.
Atopic dermatitis (AD) is characterized by reduced barrier function, reduced innate immune activation and susceptibility to Staphylococcus aureus. Host susceptibility factors are suggested by monogenic disorders associated with AD-like phenotypes and can be medically modulated. S. aureus contributes to AD pathogenesis and can be mitigated by antibiotics. Recent work has revealed that the skin microbiome differs significantly between healthy controls and patients with AD, including decreased Gram-negative bacteria in AD. However, little is known about the potential therapeutic benefit of microbiome modulation. To evaluate if parameters of AD pathogenesis are altered after exposure to different culturable Gram-negative (CGN) bacteria collected from human skin. CGN bacteria were collected from healthy controls and patients with AD. Impacts on cellular and culture-based models of immune, epithelial and bacterial function were evaluated. Representative strains were evaluated in the MC903 mouse model of AD. We found that CGN bacteria taken from healthy volunteers but not from patients with AD were associated with enhanced barrier function, innate immunity activation and control of S. aureus. Treatment with CGN from healthy controls improved outcomes in a mouse model of AD. These findings have led to the formation of a clinical trial using a live-biotherapeutic approach for treatment of patients with AD.
Singapore Immunology Network, Singapore
Title: The genetic variants control resistin expression through promoter suppression which also leads to the modulation of resistin associated disease pathways
Time : 12:20-12:50
Resistin is a member of adepokine family of cytokines and is known to modulate a diverse set of chemokines and cytokines. In humans, resistin is primarily produced by immune cell other than adipocytes which is the major source in mouse. It has been widely studied in the context of human inflammatory and metabolic diseases. The putative role of resistin in the pathogenesis of human diseases led to several genetic studies in different populations. Resistin is well known to be regulated by Cis- regulatory variants and also led to the predisposition towards diseases, but recognizing the precise targets, mechanisms and biological implications of resistin associated cis-regulatory variants are still poorly understood.
Based on whole blood, cell type specific eQTLs, resistin promoter reporter analysis, EMSA, inhibition study and bisulphite sequencing, we propose that the suppression of resistin promoter is the underlying mechanisms for genetic regulation of resistin expression in monocytes. Also a genetically defined Cohort based immune-phenotyping and plasma biomarkers analysis showed a significant modulation of immune cells and plasma biomarker which are known to be associated with inflammatory diseases.
Our study could provide detailed understanding about the role of resistin associated genetic cis-regulatory variants in the context inflammatory diseases and leads to the better identification and design of new therapeutic targets in the field of inflammation.
Seoul National University, Republic of Korea
Eun-Hee Shin has her expertise in immunology and diagnosis in parasitology and tropical medicine. In particular, she studied on biological and immunological response of a protozoa, Toxoplasma gondii in the infected host and published many papers in this area. Besides, she has worked in the field of the mucosal immunity in other water-borne protozoa and food borne trematode. Moreover, she studied on the immune response of natural products as an immunologist.
Profilin-like protein in Toxoplasma gondii (TgPLP) is a Toll-Like Receptor (TLR) agonist. In this study, we investigated whether TgPLP has an adjuvant effect on immune function in autologous whole-tumor-cell vaccine (AWV) treatment. Mice vaccinated with AWV together with recombinant TgPLP protein had smaller CT26 tumors and increased survival. TgPLP treatment strongly increased the production of IL-12 through MyD88 signaling and several chemokines, including CCL5, CCL12 and XCL1, in bone marrow-derived macrophages (BMMs). In addition, TgPLP increased the phagocytosis of tumor cells by BMMs and promoted immune cell mobility on a tumor-matrigel scaffold. TgPLP triggered immune responses as demonstrated by increased expression of antigen presenting cell markers (MHC class I and II, B7.1 and B7.2) in BMMs and increased IL-12 and IFN-γ expression in mice. Mice vaccinated with AWV and TgPLP had more immune cells (CD4+ and CD8+ T cells, natural killer cells and macrophages) in the spleen and higher total IgG and IgG2a concentrations in the blood than mice vaccinated with AWV alone. These findings suggest that TgPLP is a TLR-based vaccine adjuvant that enhances antitumor immune responses during vaccination with AWV.
University of Abuja, Nigeria
Title: Situational overview on diagnosis and control of major emerging viral zoonoses recently reported in Nigeria
Time : 14:20-14:50
Samuel Mailafia is an expert in microbiology and molecular epidemiology. His passion in eradicating emerging viral zoonoses in Nigeria and Africa is overwhelming. His open and contextual trace-back analysis of true sources of infection of bacterial and viral diseases has stimulated a lot of interest in global control of infectious diseases.
Statement of the Problem: Nigeria and many parts of the world have experienced outbreaks of emerging viral zoonoses. These diseases resulted in serious economic losses such as condemnation of infected animals and carcasses, eventual death and debilitation. Public health concern in humans results in global panic and death. Africa presents conducive environment for the sustenance of the reservoir hosts and vectors of this diseases. The poor state of health facilities in developing countries poses serious threats to the diagnosis, control, prevention and total eradication of the disease. Emerging viral zoonoses recently reported within the past two years in Nigeria includes: Avian influenza, Ebola disease and Lassa fever and Zika viral disease. The factors that led to the emergence of these zoonoses included environment, demography, pathogen mutation and presence of host or vectors. Scientists have reported that environmental changes and mutation could disseminate progeny virions which could increase risk of infection. However, most of these perspectives have not been verified. The purpose of our study is to seek to address the experience Nigeria had from the control of these diseases with possibility of analyzing the serological and molecular diagnostic tools used to control the disease locally. It is further believed that the information gained will be useful in the device of new strategies for eradication of the disease globally.
Findings: Emerging viral zoonoses have created great fear in Nigeria. Unconventional traditional remedies were sought, the government through global assistance initiated and executed local diagnostic framework for the control of these diseases.
Conclusion & Significance: The study is significant as it uncovers the risks and diagnostic potentials of Nigeria in controlling emerging diseases.
Recommendations: Developing countries needs diagnostic aids. The experience gained in the control of viral zoonoses will be useful in developing new global control programs.
MPhil, Physical Chemistry, University of Sri Jayewardenepura, Sri Lanka.
Title: Anti-biofilm activity of citrate intercalated layered double hydroxide against selected biofilm forming uropathogens
Time : 14:50-15:20
Buddhika Gayani is currently an MPhil student of Physical Chemistry at University of Sri Jayewardenepura, Sri Lanka. Her current research work explores nanomaterial solutions for potential anti-biofilm applications. In addition, she works on 3D printing of silicon based polymer materials. She holds BSc special degree in Chemistry from University of Sri Jayewardenepura, Sri Lanka. During her undergraduate research works, she has successfully used bamboo activated carbon for water purification applications.
Background & Aim: Citrate is one of promising anti-biofilm forming agents use to prevent biofilm formation as a catheter lock solution and as an oral intake. However, maintaining concentration of citrate for a long period of time will be beneficial in order to design a prolonged treatment. This study focused to determine the inhibitory effect of citrate intercalated Mg and Al layered double hydroxides (citrate-LDH) as a slow releasing agent against Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis.
Methodology: The influence of citrate-LDH synthesized by one step co-precipitation reaction was investigated against mono- and co-cultures of P. aeruginosa, S. aureus and E. faecalis grown in brain heart infusion broth. The inhibitory effect and the minimum inhibitory concentration (MIC) were determined using agar well diffusion method and pour plate method, respectively. The minimum biofilm inhibitory concentration (MBIC) and the minimum killing time for 48 hours matured biofilms were determined by MTT viability assay.
Results & Discussion: For all tested strains, the MIC value of citrate-LDH was 1×10-5 g/mL while the MBIC value was 0.01 g/mL for an average 70% reduction and 0.10 g/mL for an average 98% reduction. The minimum killing time was 6 hours for MBIC70 and it was constant for all 48 hours confirming the slow releasing ability of citrate from LDH nanohybrid. The scanning electron microscopic images reveal the biofilm inhibitory effect of citrate-LDH as it has reduced the population of microorganism and extracellular polysaccharide matrix considerably compared to the control.
Conclusion: Thus, citrate-LDH has a sustainable biofilm reducible activity against tested uropathogens which will be a potential future anti-biofilm agent in treating urinary tract infections.
PhD, Abertay University, Dundee
Title: Gastrointestinal parasites of turkeys (Meleagris gallopavo) in Gwagwalada Area Council, Abuja, Nigeria
Time : 15:20-15:50
Balarabe Rabiu Mohammed has completed his PhD in Molecular Entomology from Abertay University, Dundee in collaboration with the Liverpool School of Tropical Medicine (LSTM) in United Kingdom. His areas of specialization have been molecular characterization of genes involved in insecticide resistant insects with particular emphasis on cytochrome p450s and nuclear factor erythroid-2factor (Nrf2) and Aryl Hydrocarbon Receptor (AhR) orthologs. Currently he is involved in the study on the differential expression of AGAP010259 (AhR) and Nf2e1 (Nrf2) candidate genes in some selected strains of Anopheles gambiae (Diptera: Culicidae). His expertise in other research areas covers the management and control of protozoan and helminthic diseases of animals and zoonotic significance.
Statement of the Problem: Gastrointestinal parasites constitute a major impediment to efficient poultry production including turkeys, thereby leading to substantial economic losses. Little is known about these parasites of turkeys in the Federal Capital Territory, Abuja. This research is therefore aimed at determining the prevalence of gastrointestinal parasites of turkey in the Gwagwalada Area Council, Abuja.
Methodology: Between April and August 2016, one hundred (100) gastrointestinal tracts (GIT) and fecal samples comprising 33% domestic and 67% exotic breeds of turkeys slaughtered in Gwagwalada Area Council abattoir and slaughter slabs were randomly collected and analyzed for intestinal parasites.
Findings: This study revealed that nematode had the highest prevalent rate of infection in both local and exotic breeds. It was further revealed that 10% of the samples were found to be negative for parasites whilst 90% were found to be positive. The only Cestode observed was Raillietina spp. (13%), nematodes (40%) and protozoa (61%). A record of mixed infection was observed in both local and exotic breeds but was higher in exotic breeds with the percentage of single infection 12%, double infection 18%, triple infection 8%, quadruple infection 10% and pentaple infection 42%.
Conclusion & Significance: The present findings led to a significant conclusion that Gwagwalada metropolis is highly enzootic for the intestinal parasites of turkeys. This study has implication on the provision of sustainable animal protein for human consumption.