Day 1 :
- Anti-Infective Agents in Medicinal Chemistry
Location: Webinar
Session Introduction
Fadil Alawi
Agrihealth NZ Ltd, Newzealand
Title: Mastitis in dairy cows: Symptoms, causes, preventions and treatments
Biography:
Dr Fadil Alawi is the founder of Pharm Innovation. Fadil is an author of over 60 scientific research publications in diverse fields and has won several innovation awards. He is listed as an inventor or co-inventor on 26 patents. Fadil has also been engaged as an expert witness in court proceedings on veterinary product development.
Fadil has a special interest in dairy mastitis treatments. He is currently engaged in a joint research with a world-renowned Melbourne academic research group on the development of innovative teat sealant formulation free of bismuth subnitrate for dairy cows.
Fadil is a member of the Controlled Released Society (CRS), Australasian Pharmaceutical Scientists Association (APSA), NZ Controlled Released Society, NZ Society of Cosmetic Chemists and a chartered member of the MRACI Cchem.
Abstract:
Mastitis is the most prevalent production limiting disease affecting dairy herds world- wide, despite the widespread implementation of mastitis control strategies. The most important effects of mastitis include reduced milk production, premature culling of chronically affected cows and significant expenditure involving drug costs for the treatment of clinical and subclinical cases plus the costs of preventative treatments and the costs associated with the discarding of milk from affected animals.
The predominant contagious pathogens are Staphylococcus aureus, Streptococcus agalactiae, and Corynebacterium bovis, while the predominant environmental pathogens are Escherichia coli, Streptococcus uberis and Streptococcus dysgalactiae. Bovine mastitis has become recognised as is an increasing problem in low somatic cell count herds and this has resulted in the rapid increase in the administering of treatments such as teat seals with or without concomitant dosing of intramammary antibiotics.
Traditionally, treatment of mastitis has relied heavily on the use of antibiotics and management procedures involving hygiene measures such as the use of teat disinfectants and thorough and effective cleaning of the milking equipment. The strong reliance on the use of antibiotics has created problems of bacterial resistance and the possibility of milk residues, both of which have potential impacts on the consumer. These two factors have given impetus to the developing of alternative more sustainable treatment options such as vaccines, use of natural antimicrobials like plant essential oils and a myriad of other more natural long-term approaches. These are discussed as part of the overall review of mastitis that follows.
Specifically, the presentation begins by providing information on the symptoms, causes, prevention and treatment of bovine mastitis. This is followed by the presenting of a range of non-traditional treatment approaches with a focus on the recent development of more natural options involving plant extracts.
James K. Bashkin
University of Missouri-Saint Louis, Unites States
Title: Breaking Rules to Develop Antiviral Drug Candidates for Small DNA Tumor Viruses and (-)Strand RNA Viruses
Biography:
James Bashkin, D.Phil. was born in Iowa City, Iowa. He started as a Biology student at the University of Arizona and graduated from the University of Calfornia-Irvine with a Chemistry degree in 1977, whereupon he enrolled in the doctoral program at the University of Oxford, U.K. In 1982, he completed his studies in organometallic chemistry under Malcolm L.H. Green and joined the lab of R. H. Holm at Harvard University for postdoctoral and NIH postdoctoral work on bioinorganic chemistry. In 1985, he joined Monsanto Corporate research where he published a variety of papers ranging from RNA chemistry to commodity organic synthesis and received several awards for green chemistry. In 1991, he joined the faculty of Washington University in St. Louis and in 1999 he returned to Monsanto. After the transitions to Pharmacia and Pfizer, he co-founded the antiviral company NanoVir, LLC with virologist Chris Fisher and began work at the University of Missouri-St. Louis. In 2011, he was appointed full professor and in 2022 received the St. Louis Award from the local section of the American Chemical Society. He published 80 papers and has 16 issued U.S. patents.
Abstract:
The current study investigates the application of pyrrole-imidazole polyamides to fighting viral diseases in cell and tissue culture. We first reported the use of polyamides against high-risk human papillomavirus (HPV) types 16, 18 and 31 in 2011. A previous report on repressing latency of HIV with polyamides had appeared from the Dervan group in 2004, while inhibition of Maloney murine leukemia virus integration with the same class of molecules was reported the previous year, and so-called "paradoxical effects," meaning the authors did not understand their observations, were reported in for effects of polyamides on HLTV-1 transcription by the same group in 2004. Through extensive molecular biology and biophysical studies (with Professor Cynthia M. Dupureur and group), we have explained the "paradoxical effects" and find these rule-breaking effects to be the basis of our observed antiviral activity. We have shown the the "rules" for DNA recognition by polyamides reported so widely by Dervan et al. do not apply to longer molecules, where enthalpy plays no role in the free energy of binding, and entropy likely associated with deaggregation of polyamides is the determining factor in providing favorable, negative Gibbs free energies of binding.This deaggregation appears to be aided by increasing the positive charge on both the C- and N-termini of polyamides, resulting in improved antiviral parameters (IC50 and IC90) and improved thermodynamic binding parameters such as the dissociation constants.We now have IC50 values as low as 8-13 nM. Of interest to medicinal and pharmaceutical chemists, our polyamides were predicted by many to be incapable of entry into cells. However, the opposite is usually the case, and active uptake is often the reason, though we have not identified the specific uptake mechanism yet. Uptake into some cells is extremely effective, including essentially primary keratinocytyes infected with episomal HPV. Another example is a range of blood cells: iv pharmacokinetics are hampered by the immediate uptake of compounds into blood cells, leaving none in the plasma to be measured and making bioavailability, by definition, zero, even though the blood cells transport the compounds to internal organs such as bone marrow, liver, and spleen.
Conclusion: It can be extremely important to ignore "rules" of science and medicinal chemistry and simply carry out experiments to see the results. Even highly flawed prior literature can inspire effective strategies for drug discovery. However, novel molecular structures may require additional creativity in the formulation and drug delivery aspects of drug development. We even found activity against Vesicular Stomatitis Virus (VSV) shortly after the two most prominent groups reported poor polyamide-RNA interactions. Their data were not wrong, but they failed to account for the range of RNA structures found in RNA genomes, which go far beyond the A-form helix of double-stranded RNA.
Abdulaziz Al-Mantashari
Umm Al-Qura University College of Science - Chemistry, Saudi Arabia
Title: Trace Metals Analysis In Electronic Cigarettes Formulations Using Atomic Spectroscopy Techniques
Biography:
Abdulaziz Al-Mantashari, Bachelor’s degree in Chemistry, King Abdulaziz University (2010), Currently a master's student in Chemistry, Umm Al-Qura University.
Abstract:
Background and objective: Electronic cigarettes (ECs) are battery-powered devices that convert liquid into an aerosol (suspension of liquid or solid or both in the gaseous state) that can be inhaled. The amount of aerosol generated can be affected by many factors including device settings, puff volume and duration. Heavy metals pose high health risk ones administered to human body at high concentrations. As electronic cigarettes are used wildly these days therefore it is important to ensure that they do not contain high level of heavy metals in their formulations. The research goal of this study is to quantify the concentration of heavy metals in the liquid of E-cigarette using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Methods: Five samples of E-liquids were purchased from the market in Saudi Arabia to quantify the level of heavy metals. Two methods were used to prepare E- liquids. First method was preparing E-liquids directly from its bottle while other method was placed E-liquids in E- cigarette's device for 20 puffs. In both methods weighed 0.2g into digestion vessel then 2 mL of deionized water and 5 mL of nitric acid were added before place digestion vessels into the microwave. All metals were quantified using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Results: The average concentration of five different samples were quantified for cadmium (Cd), lead (Pb), arsenic (As), mercury (Hg), Chromium (Cr), Tin (Sn) and Copper (Cu) in the first method were 0.963, 6.698, 11.845, 12.390, 0.000, 5.932 and 5.654 μg/l, respectively. On the other hand, the concentration in the second method for cadmium (Cd), lead (Pb), arsenic (As), mercury (Hg), Chromium (Cr), Tin (Sn) and Copper (Cu) were 0.114, 131.853, 12.184, 7.480, 154.042, 134.189 and 442.980 μg/l, respectively. Conclusion: Our data suggest that e-cigarettes could be a source of harmful metal exposure ( Pd , Cr , Sn and Cu ) The tank samples had higher amounts , indicating that coil contact caused E-liquid contamination.
Md. Shafayat Hossain
Chinese Academy of Sciences, China
Title: Glutathionylation promotes Gbb degradation by proteasome-mediated pathway
Biography:
Talented and resourceful academician and researcher, offering 10years’ research and teaching experience bearing field of Neurobiology, Molecular Biology, Pharmacology, Physiology, Protein Biochemistry, Biotechnology, and Genetics. Successfully awarded a doctorate from world-leading research organization, Chinese Academy of Sciences (CAS) with most prestigious CAS- TWAS (Italy) President fellowship of China. Excellent capabilities with top-ranking research laboratories/organizations (University of Cambridge and University of York) for solving unanswered biological questions. Dedicated biological researchers for more than 7 years of research experiences in the state key laboratory of molecular developmental biology. Self-motivated and goal-oriented individual with multiple oversee projects handing capabilities. Having proven leadership, excellent communication skills, and strong student management skills to achieve high productivity and improve the institute.
Abstract:
Synapse, the specialized contacting site between neurons and their target cells, is crucial for brain function. One main interest in the laboratory is to understand how synapse development is regulated. To identify a novel gene that regulates Neuromuscular Junction (NMJ) growth, we have carried out an RNAi knockdown screen for NMJ overgrowth phenotype. We categorized the candidate genes into calcium signaling, transcription factors, redox, and miscellaneous subgroup.
From the unbiased genetic screen, we found postsynaptic knockdown of glutathione S- transferase omega 1 (GstO1) showed significantly more synaptic boutons at the NMJs. To understand the function of GstO1 in synapse development, we generated multiple mutations of GstO1, the Drosophila ortholog of GSTO1 by CRIPR/Cas9 technology.
Phenotypic analysis of tissue-specific alterations of GstO1 showed that GstO1 restrains NMJ growth post-synaptically. Additionally, GstO1 mutants showed impaired larval locomotion including larval roll-over and crawling. Several signaling pathways that regulate
synapse development. To determine if GstO1 loss-of-function does indeed lead to NMJ overgrowth through a BMP signaling pathway, we quantified the level of phosphorylated MAD (pMad), an indicator of BMP signaling strength, in NMJ synapses and found pMad staining intensity was upregulated in GstO1 mutants. To examine possible involvement of BMP signaling in mediating the overgrowth of synaptic boutons in GstO1 mutants, we examined genetic interactions between GstO1 and the BMP pathway components. Removal of one copy of gbb (heterozygous gbb4 mutation) did not effect on NMJ growth but suppressed the excess bouton and satellite bouton phenotype of GstO1 mutants. As GstO1 acts in the postsynaptic muscles and Gbb is secreted from muscles to retrogradely activate BMP signaling. Intracellular Gbb intensity around the synaptic terminals and the number of Gbb positive puncta were increased in GstO1 mutants. Along with increased intracellular Gbb, extracellular Gbb at NMJ synapses was also upregulated in GstO1 mutants. To verify the effect of GstO1 on secreted Gbb, we knocked down GstO1 in Drosophila S2 cells and found an increased level of unprocessed cytoplasmic full-length Gbb in the cell lysates and the processed mature Gbb level in the culture medium.
Glutathione (GSH) is a universal antioxidant in aerobic cells. The GSH/GSSG ratio is a redox state indicator. We found that in GstO1 mutants, the ratio of GSH/GSSG was increased, indicating disrupted redox homeostasis. Grx1 acts as the main deglutathionylating enzyme and plays a critical role in redox homeostasis as well as redox signaling. Overexpression of glutaredoxin 1 (Grx1) produced similar phenotype as GstO1 mutants. As Gbb level was upregulated in GstO1 mutant and GstO1 genetically interact with Gbb, we speculated that GstO1 might interact physically with Gbb. By co-immunoprecipitation experiment, we found that GstO1 physically interacted with Gbb and was perfectly co-localized with Gbb. To find out the localization of GstO1, we found that GstO1 localized in ER, early endosomes and recycling endosomes but not in late endosomes.
GstO1 specifically glutathionylates Gbb using anti-GSH antibody under non-reducing conditions. Mass spectrometry revealed two potential glutathionylated residues, cysteines 420 and 354, in the C-terminal of Gbb. We set out to dissect the mechanisms mediating negative regulation of Gbb by GstO1 through examining the stability of Gbb protein in S2 cells at various time points after treatment with the protein synthesis inhibitor cycloheximide (ChX). GstO1 knockdown increases Gbb stability. We observed a relatively stable level of Gbb after co-treated with a proteasome inhibitor (MG132) and cycloheximide (ChX). Further biochemical results demonstrate that GstO1 promotes ubiquitin-mediated degradation of Gbb.
Knockdown of ctrip mimics the increased satellite bouton phenotype of GstO1 mutants. The intensity of extracellular Gbb at NMJ synapses was increased in knowndown of ctrip. These results indicate that Ctrip may be a major E3 ligase to degrade Gbb in postsynaptic muscles.
Conclusion:
This study revealed for the first time a new mode of protein stability regulation, that is, glutathione modification promotes ubiquitination modification, which in turn promotes the proteasome degradation of the target protein. As GSTO1 is involved in neurodegenerative diseases such as Parkinson’s disease and Alzheimer’s disease, our finding of a novel physiological regulatory mechanism for controlling Gbb stability by GstO1 provides a potential therapeutic target in the treatment of related diseases.
Biography:
Abstract:
The Cysteine-based mesenchymal–epithelial transition (c-Met) is a receptor tyrosine kinase that plays a definitive role during cancer progression and was identified as a possible target for antiangiogenisis drugs. In the present study, different protocols of computer-based drug design were performed. Construction of predictive pharmacophore model using HypoGen algorithm resulted in a validated model of four features of positive ionizable, hydrogen bond acceptor, hydrophobic and ring aromatic features with a correlation coefficient of 0.87, a configuration cost of 14.95 and a cost difference of 357.92. The model revealed a promising predictive power and had >90% probability of representing true correlation with the activity data. The model was established using Fisher’s validation test at the 95% confidence level and test set prediction (r = 0.96), furthermore, the model was validated by mapping of set of compounds undergoing clinical trials as class â…¡ c-met inhibitors. The generated valid pharmacophore model was then anticipated for virtual screening of three data bases. Moreover, scaffold hopping using replace fragments protocol was implemented. Hits generated were filtered according to Lipinski’s rule; 510 selected hits were anatomized and subjected to molecular docking studies into the crystal structure of c-Met kinase. The good correlation between docking scores and ligand pharmacophore mapping fit values provided a reliable foundation for designing new potentially active candidates that may target c- Met kinase. Eventually, eight hits were selected as potential leads. Subsequently, seven (Hits) have displayed a higher dock score and demonstrated key residue interactions with stable molecular dynamics simulation. Therefore, these c-Met kinase inhibitors may further serve as new chemical spaces in designing new compounds.