ORCID Profile
0000-0002-9756-7083
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Chemical Engineering | Medical Biotechnology | Industrial Biotechnology | Functional Materials | Chemical Engineering Design | Interdisciplinary Engineering Not Elsewhere Classified | Engineering/Technology Instrumentation | Animal Protection (Pests and Pathogens) | Manufacturing Engineering not elsewhere classified | Chemical Engineering Not Elsewhere Classified | Industrial Biotechnology not elsewhere classified | Medical Molecular Engineering of Nucleic Acids and Proteins |
ANZSRC Socio-Economic Objective (SEO)
Human Pharmaceutical Treatments (e.g. Antibiotics) | Expanding Knowledge in Engineering | Infectious diseases | Human Pharmaceutical Products not elsewhere classified | Veterinary Pharmaceutical Products not elsewhere classified | Veterinary Biological Preventatives (e.g. Vaccines) | Prevention—biologicals (e.g. vaccines) | Manufacturing not elsewhere classified | Scientific instrumentation
Related Links
Publications
Improved fusion tag cleavage strategies in the downstream processing of self-assembling virus-like particle vaccines
Publisher: Elsevier BV
Date: 04-2014
Self-adjuvanting modular virus-like particles for mucosal vaccination against group A streptococcus (GAS)
Publisher: Elsevier BV
Date: 04-2013
DOI: 10.1016/J.VACCINE.2013.02.013
Abstract: Group A streptococcus (GAS) causes a wide range of diseases, some of them related to autoimmune diseases triggered by repeated GAS infections. Despite the fact that GAS primarily colonizes the mucosal epithelium of the pharynx, the main mechanism of action of most vaccine candidates is based on development of systemic antibodies that do not cross-react with host tissues, neglecting the induction of mucosal immunity that could potentially block disease transmission. Peptide antigens from GAS M-surface protein can confer protection against infection however, translation of such peptides into immunogenic mucosal vaccines that can be easily manufactured remains a challenge. In this work, a modular murine polyomavirus (MuPyV) virus-like particle (VLP) was engineered to display a GAS antigenic peptide, J8i. Heterologous modules containing one or two J8i antigen elements were integrated with the MuPyV VLP, and produced using microbial protein expression, standard purification techniques and in vitro VLP assembly. Both modular VLPs, when delivered intranasally to outbred mice without adjuvant, induced significant titers of J8i-specific IgG and IgA antibodies, indicating significant systemic and mucosal responses, respectively. GAS colonization in the throats of mice challenged intranasally was reduced in these immunized mice, and protection against lethal challenge was observed. This study shows that modular MuPyV VLPs prepared using microbial synthesis have potential to facilitate cost-effective vaccine delivery to remote communities through the use of mucosal immunization.
3PUJ: Crystal structure of the MUNC18-1 and SYNTAXIN4 N-Peptide complex.
Publisher: Worldwide Protein Data Bank
Date: 19-01-2011
DOI: 10.2210/PDB3PUJ/PDB
The structure of the caspase recruitment domain of BinCARD reveals that all three cysteines can be oxidized
Publisher: International Union of Crystallography (IUCr)
Date: 11-04-2013
An environmentally sustainable biomimetic production of cyclic disulfide-rich peptides
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0GC01366H
Abstract: An environmentally sustainable production platform for a variety of correctly folded cyclic disulfide-rich peptides with enhanced yields.
Liposome reconstitution and modulation of recombinant N-methyl-D-aspartate receptor channels by membrane stretch
Publisher: Proceedings of the National Academy of Sciences
Date: 30-01-2007
Abstract: In this study, the heteromeric N -methyl- d -aspartate (NMDA) receptor channels composed of NR1a and NR2A subunits were expressed, purified, reconstituted into liposomes, and characterized by using the patch cl technique. The protein exhibited the expected electrophysiological profile of activation by glutamate and glycine and internal Mg 2+ blockade. We demonstrated that the mechanical energy transmitted to membrane-bound NMDA receptor channels can be exerted directly by tension developed in the lipid bilayer. Membrane stretch and application of arachidonic acid potentiated currents through NMDA receptor channels in the presence of intracellular Mg 2+ . The correlation of membrane tension induced by either mechanical or chemical stimuli with the physiological Mg 2+ block of the channel suggests that the synaptic transmission can be altered if NMDA receptor complexes experience local changes in bilayer thickness caused by dynamic targeting to lipid microdomains, electrocompression, or chemical modification of the cell membranes. The ability to study gating properties of NMDA receptor channels in artificial bilayers should prove useful in further study of structure–function relationships and facilitate discoveries of new therapeutic agents for treatment of glutamate-mediated excitotoxicity or analgesic therapies.
Microbial bio‐production of a recombinant stimuli‐responsive biosurfactant
Publisher: Wiley
Date: 05-08-2008
DOI: 10.1002/BIT.22037
Abstract: Biosurfactants have been the subject of recent interest as sustainable alternatives to petroleum-derived compounds in areas ranging from soil remediation to personal and health care. The production of naturally occurring biosurfactants depends on the presence of complex feed sources during microbial growth and requires multicomponent enzymes for synthesis within the cells. Conversely, designed peptide surfactants can be produced recombinantly in microbial systems, enabling the generation of improved variants by simple genetic manipulation. However, inefficient downstream processing is still an obstacle for the biological production of small peptides. We present the production of the peptide biosurfactant GAM1 in recombinant E. coli. Expression was performed in fusion to maltose binding protein using chemically defined minimal medium, followed by a single-step affinity capture and enzymatic cleavage using tobacco etch virus protease. Different approaches to the isolation of peptide after cleavage were investigated, with special emphasis on rapid and simple procedures. Solvent-, acid-, and heat-mediated precipitation of impurities were successfully applied as alternatives to post-cleavage chromatographic peptide purification, and gave peptide purities exceeding 90%. Acid precipitation was the method of choice, due to its simplicity and the high purification factor and recovery rate achieved here. The functionality of the bio-produced peptide was tested to ensure that the resulting peptide biosurfactant was both surface active and able to be triggered to switch between foam-stabilizing and foam-destabilizing states.
Characterization of the Plasmodium falciparum M17 leucyl aminopeptidase. A protease involved in amino acid regulation with potential for antimalarial drug development.
Publisher: Elsevier BV
Date: 2006
Characterizing Enterovirus 71 and Coxsackievirus A16 virus-like particles production in insect cells
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.YMETH.2015.09.023
Abstract: Enterovirus 71 (EV71) and Coxsackievirus A16 (CVA16) are two viruses commonly responsible for hand, foot and mouth disease (HFMD) in children. The lack of prophylactic or therapeutic measures against HFMD is a major public health concern. Insect cell-based EV71 and CVA16 virus-like particles (VLPs) are promising vaccine candidates against HFMD and are currently under development. In this paper, the influence of insect cell line, incubation temperature, and serial passaging effect and stability of budded virus (BV) stocks on EV71 and CVA16 VLP production was investigated. Enhanced EV71 and CVA16 VLP production was observed in Sf9 cells compared to High Five™ cells. Lowering the incubation temperature from the standard 27°C to 21°C increased the production of both VLPs in Sf9 cells. Serial passaging of CVA16 BV stocks in cell culture had a detrimental effect on the productivity of the structural proteins and the effect was observed with only 5 passages of BV stocks. A 2.7× higher production yield was achieved with EV71 compared to CVA16. High-resolution asymmetric flow field-flow fractionation couple with multi-angle light scattering (AF4-MALS) was used for the first time to characterize EV71 and CVA16 VLPs, displaying an average root mean square radius of 15±1nm and 15.3±5.8 nm respectively. This study highlights the need for different approaches in the design of production process to develop a bivalent EV71 and CVA16 vaccine.
A microbial platform for rapid and low-cost virus-like particle and capsomere vaccines
Publisher: Elsevier BV
Date: 09-2011
DOI: 10.1016/J.VACCINE.2011.05.075
Abstract: Studies on a platform technology able to deliver low-cost viral capsomeres and virus-like particles are described. The technology involves expression of the VP1 structural protein from murine polyomavirus (MuPyV) in Escherichia coli, followed by purification using scaleable units and optional cell-free VLP assembly. Two insertion sites on the surface of MuPyV VP1 are exploited for the presentation of the M2e antigen from influenza and the J8 peptide from Group A Streptococcus (GAS). Results from testing on mice following subcutaneous administration demonstrate that VLPs are self adjuvating, that adding adjuvant to VLPs provides no significant benefit in terms of antibody titre, and that adjuvanted capsomeres induce an antibody titre comparable to VLPs but superior to unadjuvanted capsomere formulations. Antibodies raised against GAS J8 peptide following immunization with chimeric J8-VP1 VLPs are bactericidal against a GAS reference strain. E. coli is easily and widely cultivated, and well understood, and delivers unparalleled volumetric productivity in industrial bioreactors. Indeed, recent results demonstrate that MuPyV VP1 can be produced in bioreactors at multi-gram-per-litre levels. The platform technology described here therefore has the potential to deliver safe and efficacious vaccine, quickly and cost effectively, at distributed manufacturing sites including those in less developed countries. Additionally, the unique advantages of VLPs including their stability on freeze drying, and the potential for intradermal and intranasal administration, suggest this technology may be suited to numerous diseases where adequate response requires large-scale and low-cost vaccine manufacture, in a way that is rapidly adaptable to temporal or geographical variation in pathogen molecular composition.
Virus assembly occurs following a pH- or Ca2+-triggered switch in the thermodynamic attraction between structural protein capsomeres
Publisher: The Royal Society
Date: 22-07-2009
Abstract: Viral self-assembly is of tremendous virological and biomedical importance. Although theoretical and crystallographic considerations suggest that controlled conformational change is a fundamental regulatory mechanism in viral assembly, direct proof that switching alters the thermodynamic attraction of self-assembling components has not been provided. Using the VP1 protein of polyomavirus, we report a new method to quantitatively measure molecular interactions under conditions of rapid protein self-assembly. We show, for the first time, that triggering virus capsid assembly through biologically relevant changes in Ca 2+ concentration, or pH, is associated with a dramatic increase in the strength of protein molecular attraction as quantified by the second virial coefficient ( B 22 ). B 22 decreases from −2.3 × 10 −4 mol ml g −2 (weak protein–protein attraction) to −2.4 × 10 −3 mol ml g −2 (strong protein attraction) for metastable and Ca 2+ -triggered self-assembling capsomeres, respectively. An assembly-deficient mutant (VP1CΔ63) is conversely characterized by weak protein–protein repulsion independently of chemical change sufficient to cause VP1 assembly. Concomitant switching of both VP1 assembly and thermodynamic attraction was also achieved by in vitro changes in ammonium sulphate concentration, consistent with protein salting-out behaviour. The methods and findings reported here provide new insight into viral assembly, potentially facilitating the development of new antivirals and vaccines, and will open the way to a more fundamental physico-chemical description of complex protein self-assembly systems.
Total cholesterol and triglycerides are associated with the development of new bone marrow lesions in asymptomatic middle-aged women - a prospective cohort study
Publisher: Springer Science and Business Media LLC
Date: 2009
DOI: 10.1186/AR2873
Insert engineering and solubility screening improves recovery of virus‐like particle subunits displaying hydrophobic epitopes
Publisher: Wiley
Date: 07-10-2015
DOI: 10.1002/PRO.2775
Growth, viral production and metabolism of a Helicoverpa zea cell line in serum-free culture
Publisher: Springer Science and Business Media LLC
Date: 2003
Intensified Downstream Processing of Monoclonal Antibodies Using Membrane Technology
Publisher: Wiley
Date: 19-10-2021
Virus-like particle formulation optimization by miniaturized high-throughput screening
Publisher: Elsevier BV
Date: 05-2013
DOI: 10.1016/J.YMETH.2013.04.019
Abstract: Virus-like particles (VLPs) are non-infectious and immunogenic virus-mimicking protein assemblies that are increasingly researched as vaccine candidates. Stability against aggregation is an important determinant dictating the viability of a pipeline VLP product, making multivariable stability data highly desirable especially in early product development stages. However, comprehensive formulation studies are challenging due to low s le availability early in developability assessment. This issue is exacerbated by industry-standard analytical techniques which are low-throughput and/or s le-consuming. This study presents a miniaturized high-throughput screening (MHTS) methodology for VLP formulation by integrating dynamic light scattering (DLS) and asymmetrical flow field-flow fractionation (AF4) in a formulation funnel analysis. Using only 2 μg of s le and 100 s per measurement, a DLS plate reader was deployed to effectively pre-screen a large experimental space, allowing a smaller set of superior formulation conditions to be interrogated at high-resolution with AF4. The stabilizing effects of polysorbate 20, sucrose, trehalose, mannitol and sorbitol were investigated. MHTS data showed that addition of 0.5% w/v polysorbate 20 together with either 40% w/v sucrose or 40% w/v sorbitol could stabilize VLPs at elevated temperatures up to 58 °C. AF4 data further confirmed that the formulation containing 40% w/v sorbitol and 0.5% w/v polysorbate 20 effectively protected VLPs during freeze-thawing and freeze-drying, increasing recoveries from these processes by 80 and 50 percentage points, respectively. The MHTS strategy presented here could be used to rapidly explore a large formulation development space using reduced amounts of s le, without sacrificing the analytical resolution needed for quality control. Such a method paves the way for rapid formulation development and could potentially hasten the commercialization of new VLP vaccines.
Dehydroepiandrosterone Sulfate Levels Are Associated with More Favorable Cognitive Function in Women
Publisher: The Endocrine Society
Date: 03-2008
DOI: 10.1210/JC.2007-2128
Abstract: It has been proposed that dehydroepiandrosterone and dehydroepiandrosterone sulfate (DHEAS) exert neuroprotective effects in the brain, yet evidence of associations between the endogenous levels of these steroids and measures of cognitive function is lacking. The objective of the study was to investigate whether circulating levels of DHEAS independently contribute to aspects of cognitive function in women in the community. This was a community-based, cross-sectional study. Two hundred ninety-five women, aged 21-77 yr, were recruited from a community-based data set and participated between September 2003 and December 2004. Women were excluded if they reported any health condition that might potentially adversely affect cognitive function. The in idual scores of a comprehensive battery of tests of cognitive function and the serum level of DHEAS (square root transformed) were measured. In the multiple linear regression analysis, the DHEAS term made a significant independent positive contribution to the Controlled Oral Word Association Test score, a measure of executive function. In addition, women with a DHEAS level in the highest tertile who also had more than 12 yr of education performed better on both Digit Span Forward and Digit Span Backward tests, which are tests of simple concentration and working memory, respectively. Higher endogenous DHEAS levels are independently and favorably associated with executive function, concentration, and working memory.
Vaccine Technology VI: Innovative and integrated approaches in vaccine development
Publisher: Elsevier BV
Date: 05-2018
Synthetic biology design to display an 18kDa rotavirus large antigen on a modular virus-like particle
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.VACCINE.2015.09.017
Abstract: Virus-like particles are an established class of commercial vaccine possessing excellent function and proven stability. Exciting developments made possible by modern tools of synthetic biology has stimulated emergence of modular VLPs, whereby parts of one pathogen are by design integrated into a less harmful VLP which has preferential physical and manufacturing character. This strategy allows the immunologically protective parts of a pathogen to be displayed on the most-suitable VLP. However, the field of modular VLP design is immature, and robust design principles are yet to emerge, particularly for larger antigenic structures. Here we use a combination of molecular dynamic simulation and experiment to reveal two key design principles for VLPs. First, the linkers connecting the integrated antigenic module with the VLP-forming protein must be well designed to ensure structural separation and independence. Second, the number of antigenic domains on the VLP surface must be sufficiently below the maximum such that a "steric barrier" to VLP formation cannot exist. This second principle leads to designs whereby co-expression of modular protein with unmodified VLP-forming protein can titrate down the amount of antigen on the surface of the VLP, to the point where assembly can proceed. In this work we elucidate these principles by displaying the 18.1 kDa VP8* domain from rotavirus on the murine polyomavirus VLP, and show functional presentation of the antigenic structure.
Sensitivity of Helicoverpa armigera nucleopolyhedrovirus polyhedra to sodium dodecyl sulfate
Publisher: Elsevier BV
Date: 2003
Sensitivity of immune response quality to influenza helix 190 antigen structure displayed on a modular virus-like particle
Publisher: Elsevier BV
Date: 09-2013
DOI: 10.1016/J.VACCINE.2013.06.087
Abstract: Biomolecular engineering enables synthesis of improved proteins through synergistic fusion of modules from unrelated biomolecules. Modularization of peptide antigen from an unrelated pathogen for presentation on a modular virus-like particle (VLP) represents a new and promising approach to synthesize safe and efficacious vaccines. Addressing a key knowledge gap in modular VLP engineering, this study investigates the underlying fundamentals affecting the ability of induced antibodies to recognize the native pathogen. Specifically, this quality of immune response is correlated to the peptide antigen module structure. We modularized a helical peptide antigen element, helix 190 (H190) from the influenza hemagglutinin (HA) receptor binding region, for presentation on murine polyomavirus VLP, using two strategies aimed to promote H190 helicity on the VLP. In the first strategy, H190 was flanked by GCN4 structure-promoting elements within the antigen module in the second, dual H190 copies were arrayed as tandem repeats in the module. Molecular dynamics simulation predicted that tandem repeat arraying would minimize secondary structural deviation of modularized H190 from its native conformation. In vivo testing supported this finding, showing that although both modularization strategies conferred high H190-specific immunogenicity, tandem repeat arraying of H190 led to a strikingly higher immune response quality, as measured by ability to generate antibodies recognizing a recombinant HA domain and split influenza virion. These findings provide new insights into the rational engineering of VLP vaccines, and could ultimately enable safe and efficacious vaccine design as an alternative to conventional approaches necessitating pathogen cultivation.
Modular engineering of a microbially-produced viral capsomere vaccine for influenza
Publisher: Elsevier BV
Date: 11-2013
Quantitative characterization of virus‐like particles by asymmetrical flow field flow fractionation, electrospray differential mobility analysis, and transmission electron microscopy
Publisher: Wiley
Date: 27-10-2008
DOI: 10.1002/BIT.22085
Abstract: Here we characterize virus-like particles (VLPs) by three very distinct, orthogonal, and quantitative techniques: electrospray differential mobility analysis (ES-DMA), asymmetric flow field-flow fractionation with multi-angle light scattering detection (AFFFF-MALS) and transmission electron microscopy (TEM). VLPs are biomolecular particles assembled from viral proteins with applications ranging from synthetic vaccines to vectors for delivery of gene and drug therapies. VLPs may have polydispersed, multimodal size distributions, where the size distribution can be altered by subtle changes in the production process. These three techniques detect subtle size differences in VLPs derived from the non-enveloped murine polyomavirus (MPV) following: (i) functionalization of the surface of VLPs with an influenza viral peptide fragment (ii) packaging of foreign protein internally within the VLPs and (iii) packaging of genomic DNA internally within the VLPs. These results demonstrate that ES-DMA and AFFFF-MALS are able to quantitatively determine VLP size distributions with greater rapidity and statistical significance than TEM, providing useful technologies for product development and process analytics.
Structural-based designed modular capsomere comprising HA1 for low-cost poultry influenza vaccination
Publisher: Elsevier BV
Date: 05-2018
DOI: 10.1016/J.VACCINE.2016.11.058
Abstract: Highly pathogenic avian influenza (HPAI) viruses cause a severe and lethal infection in domestic birds. The increasing number of HPAI outbreaks has demonstrated the lack of capabilities to control the rapid spread of avian influenza. Poultry vaccination has been shown to not only reduce the virus spread in animals but also reduce the virus transmission to humans, preventing potential pandemic development. However, existing vaccine technologies cannot respond to a new virus outbreak rapidly and at a cost and scale that is commercially viable for poultry vaccination. Here, we developed modular capsomere, subunits of virus-like particle, as a low-cost poultry influenza vaccine. Modified murine polyomavirus (MuPyV) VP1 capsomere was used to present structural-based influenza Hemagglutinin (HA1) antigen. Six constructs of modular capsomeres presenting three truncated versions of HA1 and two constructs of modular capsomeres presenting non-modified HA1 have been generated. These modular capsomeres were successfully produced in stable forms using Escherichia coli, without the need for protein refolding. Based on ELISA, this adjuvanted modular capsomere (CaptHA1-3C) induced strong antibody response (almost 10
The relationship between self-reported sexual satisfaction and general well-being in women
Publisher: Oxford University Press (OUP)
Date: 10-2009
DOI: 10.1111/J.1743-6109.2009.01406.X
Abstract: The extent to which low sexual function or sexual dissatisfaction in women impacts on well-being remains uncertain, yet this is a critical issue in the controversy as to the benefits of pharmacotherapy for women seeking treatment for female sexual dysfunction. Aim. To explore the relationship between well-being and self-perceived satisfaction with sexual function in women and to determine if there is an independent effect of menopausal status or age. A community-based cross-sectional study. A total of 421 women, aged 18 to 65 years were recruited from the community. Women were required to self-identify at study outset as being either satisfied or dissatisfied with their sexual life and be premenopausal or postmenopausal. Scores from the Psychological General Well-Being Index (PGWB), the Beck Depression Index (BDI) and a daily diary of sexual function. A group of 349 women were included in the analysis. Total PGWB and domain scores of positive well-being and vitality were lower in dissatisfied women compared to satisfied women. PGWB total and domain scores of depressed mood, positive well-being and vitality were higher in older women. Menopause did not have an independent effect on well-being. Women who self-identify as having sexual dissatisfaction have lower psychological general well-being. These findings reinforce the importance of addressing sexual health and well-being in women as an essential component of their health care.
Bioengineering virus-like particles as vaccines
Publisher: Wiley
Date: 17-12-2013
DOI: 10.1002/BIT.25159
Abstract: Virus-like particle (VLP) technology seeks to harness the optimally tuned immunostimulatory properties of natural viruses while omitting the infectious trait. VLPs that assemble from a single protein have been shown to be safe and highly efficacious in humans, and highly profitable. VLPs emerging from basic research possess varying levels of complexity and comprise single or multiple proteins, with or without a lipid membrane. Complex VLP assembly is traditionally orchestrated within cells using black-box approaches, which are appropriate when knowledge and control over assembly are limited. Recovery challenges including those of adherent and intracellular contaminants must then be addressed. Recent commercial VLPs variously incorporate steps that include VLP in vitro assembly to address these problems robustly, but at the expense of process complexity. Increasing research activity and translation opportunity necessitate bioengineering advances and new bioprocessing modalities for efficient and cost-effective production of VLPs. Emerging approaches are necessarily multi-scale and multi-disciplinary, encompassing erse fields from computational design of molecules to new macro-scale purification materials. In this review, we highlight historical and emerging VLP vaccine approaches. We overview approaches that seek to specifically engineer a desirable immune response through modular VLP design, and those that seek to improve bioprocess efficiency through inhibition of intracellular assembly to allow optimal use of existing purification technologies prior to cell-free VLP assembly. Greater understanding of VLP assembly and increased interdisciplinary activity will see enormous progress in VLP technology over the coming decade, driven by clear translational opportunity.
Sexual function in well women: Stratification by sexual satisfaction, hormone use, and menopause status
Publisher: Oxford University Press (OUP)
Date: 05-2008
DOI: 10.1111/J.1743-6109.2008.00780.X
Abstract: Satisfaction with sexual function in community-based women has not been well-described, and little is known of differences in sexual function between pre-(PreM) and postmenopausal (PM) women. The aim of this article was to describe sexual function in PreM and PM women who self-identify as being satisfied or dissatisfied with their sexual life. A cross-sectional questionnaire study was conducted among 349 sexually active community-based women, aged 20-65 years, who self-identified as being either satisfied or dissatisfied with their sexual life. Scores from a daily diary of sexual function for 4 weeks, examining the frequency of sexual thoughts, interest, and activity. One hundred and eighty-four women (53%) were PreM, and 165 (47%) were dissatisfied with their sexual life. The median number of days with sexual activity or events per month for all women was 8 (ranges 2-28 days 2-57 events). Ninety-two percent of reported events involved a partner, 86% involved intercourse, and in 40% the woman initiated the activity. Women satisfied with their sexual life had higher frequencies of sexual thoughts, interest, events, and initiation of activity than dissatisfied women (P < 0.0001). PreM satisfied women had higher frequencies of sexual thoughts, numbers of days with sexual activity, and events per month than PM satisfied women (P < 0.05). PreM oral contraceptive pill (OCP) users had significantly lower average frequencies of sexual thoughts, interest, and days of sexual activity per month (P < 0.05), whereas PM women hormone therapy (HT) users had higher frequencies of sexual thoughts and sexual interest (P = 0.04 and P = 0.05, respectively) compared to nonusers. There were no differences in sexual function between PreM and PM women who were sexually dissatisfied. Sexual activity mostly involved a partner, partner initiation, and intercourse. Sexually satisfied women reported more sexual thoughts, interest, events, and initiation of sexual activity than dissatisfied women. PreM sexually satisfied women reported more sexual thoughts, days with sexual activity, and sexual events per month compared to PM satisfied women. OCP and HT use appeared to have contrasting effects on sexual function.
The chromatography-free release, isolation and purification of recombinant peptide for fibril self-assembly
Publisher: Wiley
Date: 12-2009
DOI: 10.1002/BIT.22447
Abstract: One of the major expenses associated with recombinant peptide production is the use of chromatography in the isolation and purification stages of a bioprocess. Here we report a chromatography-free isolation and purification process for recombinant peptide expressed in Escherichia coli (E. coli). Initial peptide release is by homogenization and then by enzymatic cleavage of the peptide-containing fusion protein, directly in the E. coli homogenate. Release is followed by selective solvent precipitation (SSP) to isolate and purify the peptide away from larger cell contaminants. Specifically, we expressed in E. coli the self-assembling beta-sheet forming peptide P(11)-2 in fusion to thioredoxin. Homogenate was heat treated (55 degrees C, 15 min) and then incubated with tobacco etch virus protease (TEVp) to release P(11)-2 having a native N-terminus. SSP with ethanol at room temperature then removed contaminating proteins in an integrated isolation-purification step it proved necessary to add 250 mM NaCl to homogenate to prevent P(11)-2 from partitioning to the precipitate. This process structure gave recombinant P(11)-2 peptide at 97% polypeptide purity and 40% overall yield, without a single chromatography step. Following buffer-exchange of the 97% pure product by bind-elute chromatography into defined chemical conditions, the resulting peptide was shown to be functionally active and able to form self-assembled fibrils. To the best of our knowledge, this manuscript reports the first published process for chromatography-free recombinant peptide release, isolation and purification. The process proved able to deliver functional recombinant peptide at high purity and potentially low cost, opening cost-sensitive materials applications for peptide-based materials.
Quantitative analysis of virus-like particle size and distribution by field-flow fractionation
Publisher: Wiley
Date: 15-04-2008
DOI: 10.1002/BIT.21710
Abstract: Asymmetric flow field-flow fractionation (AFFFF) coupled with multiple-angle light scattering (MALS) is a powerful technique showing potential for the analysis of pharmaceutically-relevant virus-like particles (VLPs). A lack of published methods, and concerns that membrane adsorption during s le fractionation may cause s le aggregation, have limited widespread acceptance. Here we report a reliable optimized method for VLP analysis using AFFFF-MALS, and benchmark it against dynamic light scattering (DLS) and transmission electron microscopy (TEM). By comparing chemically identical VLPs having very different quaternary structure, sourced from both bacteria and insect cells, we show that optimized AFFFF analysis does not cause significant aggregation, and that accurate size and distribution information can be obtained for heterogeneous s les in a way not possible with TEM and DLS. Optimized AFFFF thus provides a quantitative way to monitor batch consistency for new vaccine products, and rapidly provides unique information on the whole population of particles within a s le.
Negative beliefs about low back pain are associated with high pain intensity and high level disability in community-based women
Publisher: Springer Science and Business Media LLC
Date: 04-11-2008
3PUK: Re-refinement of the crystal structure of Munc18-3 and Syntaxin4 N-peptide complex.
Publisher: Worldwide Protein Data Bank
Date: 19-01-2011
DOI: 10.2210/PDB3PUK/PDB
Energetic Changes Caused by Antigenic Module Insertion in a Virus-Like Particle Revealed by Experiment and Molecular Dynamics Simulations
Publisher: Public Library of Science (PLoS)
Date: 12-09-2014
High-level expression of soluble viral structural protein in Escherichia coli
Publisher: Elsevier BV
Date: 20-03-2008
DOI: 10.1016/J.JBIOTEC.2007.12.004
Abstract: Pharmaceutically relevant virus-like particles (VLPs) can potentially be manufactured cheaply and efficiently through in vitro assembly of viral structural protein in cell-free reactors, but a bottleneck for this processing route is the currently low-level expression of soluble viral protein in efficient cell factories such as Escherichia coli (E. coli). Here, we report expression levels of up to 180 mg L(-1) that are achievable from low-cell-density E. coli cultures using a simple and low cost strategy. We investigated effects of host strain, plasmid, inducer concentration, pre-induction temperature and cell density at induction with design of experiment (DOE). The statistical approach successfully identified significant effects and their interactions, and provided insights into the role of codon-usage effects in expression of viral structural protein. In particular, our results support the notion that full codon optimization may be unnecessary to improve expression of viral genes rich in E. coli rare codons using a strategically modified host cell could provide a simpler and cheaper alternative.
Prevalence and incidence of urinary incontinence in women: Review of the literature and investigation of methodological issues
Publisher: Wiley
Date: 26-02-2008
DOI: 10.1111/J.1442-2042.2007.01976.X
Abstract: Urinary incontinence in women is common and has a significant impact on the physical, psychological and socio-economic aspects of life. The aims of this study were to review the published reports on the prevalence and incidence of urinary incontinence in Australian women and to examine the methodological issues associated with these studies. Electronic searches of Medline, EMBASE and the Current Index to Nursing and Allied Health Literature databases were undertaken using 'Medical Subject Heading' terms and 'free text' words. We retrieved papers that investigated the prevalence and/or incidence of urinary incontinence in Australian women and were published in English after 1980. Methodological data from each study were tabulated. Seven studies were identified which examined the prevalence of urinary incontinence and two studies that reported its incidence. The prevalence of urinary incontinence varied between 12.8% and 46.0%. Study heterogeneity was a consequence of response rates, the inclusion of women in institutional care, the method of data collection, the questions used to identify different types of urinary incontinence and the way these questions were reported, the period over which the urinary incontinence had occurred and the severity of the incontinence. Two studies which examined incidence provided evidence that urinary incontinence can be a transient phenomenon. Research into the incidence and prevalence of urinary incontinence in Australian women exhibits significant heterogeneity in the findings due to methodological limitations. There is a need for future studies to employ validated instruments and give careful attention to the selection of participants and the reporting of age-specific data.
Co-administration of non-carrier nanoparticles boosts antigen immune response without requiring protein conjugation
Publisher: Elsevier BV
Date: 06-2014
DOI: 10.1016/J.VACCINE.2014.04.043
Abstract: Nanotechnology promises a revolution in medicine including through new vaccine approaches. The use of nanoparticles in vaccination has, to date, focused on attaching antigen directly to or within nanoparticle structures to enhance antigen uptake by immune cells. Here we question whether antigen incorporation with the nanoparticle is actually necessary to boost vaccine effectiveness. We show that the immunogenicity of a sub-unit protein antigen was significantly boosted by formulation with silica nanoparticles even without specific conjugation of antigen to the nanoparticle. We further show that this effect was observed only for virus-sized nanoparticles (50 nm) but not for larger (1,000 nm) particles, demonstrating a pronounced effect of nanoparticle size. This non-attachment approach has potential to radically simplify the development and application of nanoparticle-based formulations, leading to safer and simpler nanoparticle applications in vaccine development.
Effect of Time of Harvest of Budded Virus on the Selection of Baculovirus FP Mutants in Cell Culture
Publisher: Wiley
Date: 2003
DOI: 10.1021/BP025577U
Abstract: Rapid formation and selection of FP (few polyhedra) mutants occurs during serial passaging of Helicoverpa armigera nucleopolyhedrovirus (HaSNPV) in insect cell culture. The production of HaSNPV for use as biopesticides requires the passaging of the virus over a number of passages to produce enough virus inoculum for large-scale fermentation. During serial passaging in cell culture, FP mutants were rapidly selected, resulting in declined productivity and reduced potency of virus. Budded virus (BV) is usually harvested between 72 and 96 h postinfection (hpi) in order to obtain a high titer virus stock. In this study, the effect of time of harvest (TOH) for BV on the selection rate of HaSNPV FP mutants during serial passaging was investigated. BV were harvested at different times postinfection, and each series was serially passaged for six passages. The productivity and percentage of FP mutants at each passage were determined. It was found that the selection of FP mutants can be reduced by employing an earlier TOH for BV. Serial passaging with BV harvested at 48 hpi showed a slower accumulation of FP mutants compared to that of BV harvested after 48 hpi. Higher cell specific yields were also maintained when BV were harvested at 48 hpi. When BV that were formed between 48 and 96 hpi were harvested and serially passaged, FP mutants quickly dominated the virus population. This suggests that the BV formed and released between 48 and 96 hpi are most likely from FP mutant infected cells.
Rapid response bioprocessing of influenza vaccines
Publisher: Elsevier BV
Date: 11-2009
Biomolecular engineering for recombinant sustainable surfactants
Publisher: Elsevier BV
Date: 11-2009
Synthetic biology for bioengineering virus‐like particle vaccines
Publisher: Wiley
Date: 31-12-2018
DOI: 10.1002/BIT.26890
Non-chromatographic preparation of a bacterially produced single-shot modular virus-like particle capsomere vaccine for avian influenza
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.VACCINE.2015.08.100
Abstract: Highly pathogenic avian influenza (HPAI) causes significant economic loss, reduced food security and poses an ongoing pandemic threat. Poultry vaccination significantly decreases these problems and recognizes that the health of humans, animals and ecosystems are connected. Low-cost manufacture of poultry vaccine matched quickly to the ever-changing circulating strain is needed for effective vaccination. Here, we re-engineered the process to manufacture bacterially synthesized modular capsomere comprising influenza M2e, previously shown to confer complete protection in challenged mice, for application in poultry. Modular capsomere was prepared using a simplified non-chromatographic salting-out precipitation method and its immunogenicity tested in vivo in poultry. Modular capsomere crudely purified by precipitation (pCapM2e) contained more contaminants than equivalent product purified by chromatography (cCapM2e). Unadjuvanted pCapM2e containing 80 EU of endotoxin per dose was inferior to highly purified and adjuvanted cCapM2e (2 EU per dose). However, addition of adjuvant to pCapM2e resulting in high immunogenicity after only a single dose of vaccination, yet without any local adverse reaction. This finding suggests a strong synergy between adjuvant, antigen and contaminants, and the possible existence of a "Goldilocks" level of contaminants, where high immunogenicity and low reactogenicity can be obtained in a single-shot vaccination. The simplified process offers potential cost and speed advantages to address the needs in influenza poultry vaccination in low-cost veterinary markets.
Advances in Protein Production Technologies
Publisher: Wiley
Date: 18-07-2012
Virus‐Like Particle Bioprocessing
Publisher: Wiley
Date: 18-07-2012
A rapid and simple screening method to identify conditions for enhanced stability of modular vaccine candidates
Publisher: Elsevier BV
Date: 08-2015
The economics of virus-like particle and capsomere vaccines
Publisher: Elsevier BV
Date: 09-2014
A new bioproduction route for a novel antimicrobial peptide
Publisher: Wiley
Date: 17-11-2010
DOI: 10.1002/BIT.22970
Abstract: Beta defensins are antimicrobial peptides (AMPs) with a broad spectrum antimicrobial behavior against pathogens while having minimal tendency to incur pathogen resistance. Human β-defensin 28 (hBD28) is a strongly cationic AMP and hence hypothesized to be highly effective in permeabilizing negatively-charged pathogen membranes. However, the scarcity of hBD28 in vivo has impeded detailed structure and antimicrobial studies of hBD28. Chemical synthesis of hBD28 rendered extremely poor yields due to inefficient cysteine oxidation. In this study, a rapid and scalable production route to produce bioactive hBD28 in Escherichia coli (E. coli) is reported. The design of a dual fusion tag expression construct was pivotal in enhancing soluble expression and easing purification of hBD28. The final hBD28 (purity >95%) displayed significant antimicrobial activity against E. coli K12 and showed dose-dependent killing kinetics. Circular dichroism spectroscopy confirmed the presence of both β-sheet and α-helix conformations in the secondary structure of hBD28.
Small-Molecule Inhibitors of the SOX18 Transcription Factor
Publisher: Elsevier BV
Date: 03-2017
DOI: 10.1016/J.CHEMBIOL.2017.01.003
Abstract: Pharmacological modulation of transcription factors (TFs) has only met little success over the past four decades. This is mostly due to standard drug discovery approaches centered on blocking protein/DNA binding or interfering with post-translational modifications. Recent advances in the field of TF biology have revealed a central role of protein-protein interaction in their mode of action. In an attempt to modulate the activity of SOX18 TF, a known regulator of vascular growth in development and disease, we screened a marine extract library for potential small-molecule inhibitors. We identified two compounds, which inspired a series of synthetic SOX18 inhibitors, able to interfere with the SOX18 HMG DNA-binding domain, and to disrupt HMG-dependent protein-protein interaction with RBPJ. These compounds also perturbed SOX18 transcriptional activity in a cell-based reporter gene system. This approach may prove useful in developing a new class of anti-angiogenic compounds based on the inhibition of TF activity.
Progression of continuous downstream processing of monoclonal antibodies: Current trends and challenges.
Publisher: Wiley
Date: 18-10-2018
DOI: 10.1002/BIT.26812
Abstract: Rapid advances in intensifying upstream processes for biologics production have left downstream processing as a bottleneck in the manufacturing scheme. Biomanufacturers are pursuing continuous downstream process development to increase efficiency and flexibility, reduce footprint and cost of goods, and improve product consistency and quality. Even after successful laboratory trials, the implementation of a continuous process at manufacturing scale is not easy to achieve. This paper reviews specific challenges in converting each downstream unit operation to a continuous mode. Key elements of developing practical strategies for overcoming these challenges are detailed. These include equipment valve complexity, favorable column aspect ratio, protein-A resin selection, quantitative assessment of chromatogram peak size and shape, holistic process characterization approach, and a customized process economic evaluation. Overall, this study provides a comprehensive review of current trends and the path forward for implementing continuous downstream processing at the manufacturing scale.
Use of a cancer registry is preferable to a direct-to-community approach for recruitment to a cohort study of wellbeing in women newly diagnosed with invasive breast cancer
Publisher: Springer Science and Business Media LLC
Date: 02-05-2008
Modular virus-like particles for sublingual vaccination against group A streptococcus
Publisher: Elsevier BV
Date: 12-2016
DOI: 10.1016/J.VACCINE.2016.11.008
Abstract: Infection with Group A streptococcus (GAS)-an oropharyngeal pathogen-leads to mortality and morbidity, primarily among developing countries and indigenous populations in developed countries. The development of safe and affordable GAS vaccines is challenging, due to the presence of various unique GAS serotypes, antigenic variation within the same serotype, and potential auto-immune responses. In the present study, we evaluated the use of a sublingual freeze-dried (FD) formulation based on immunogenic modular virus-like particles (VLPs) carrying the J8 peptide (J8-VLPs) as a potential safe and cost-effective GAS vaccine for inducing protective systemic and mucosal immunity. By using in vivo tracing of the sublingual J8-VLPs, we visualized the draining of J8-VLPs into the submandibular lymph nodes, in parallel with its rapid absorption into the systemic circulation, which support the induction of effective immune responses in both systemic and mucosal compartments. The sublingual administration of J8-VLPs resulted in a high serum IgG antibody level, with a good balance of Th1 and Th2 immune responses. Of note, sublingual vaccination with J8-VLPs elicited high levels of IgA antibody in the saliva. The co-administration of mucosal adjuvant cholera toxin (CT) further enhanced the increase in salivary IgA antibody levels induced by the J8-VLPs formulation. Moreover, the levels of salivary IgA and serum IgG observed following the administration of the CT-adjuvanted FD formulation of J8-VLPs (FD-J8-VLPs) and non-FD formulation of J8-VLPs were comparable. In fact, the saliva isolated from mice immunized with J8-VLPs and FD-J8-VLPs with CT demonstrated opsonizing activity against GAS in vitro. Thus, we observed that the sublingually delivered FD formulation of microbially produced modular VLPs could prevent and control GAS diseases in endemic areas in a cost-effective manner.
Is Pichia pastoris a realistic platform for industrial production of recombinant human interferon gamma?
Publisher: Elsevier BV
Date: 2017
DOI: 10.1016/J.BIOLOGICALS.2016.09.015
Abstract: Human interferon gamma (hIFNγ) is an important cytokine in the innate and adaptive immune system, produced commercially in Escherichia coli. Efficient expression of hIFNγ has been reported once for Pichia pastoris (Wang et al., 2014) - a proven heterologous expression system. This study investigated hIFNγ expression in P. pastoris replicating the previous study and expanding by using four different strains (X33: wild type GS115: HIS
Assessing sexual function in well women: validity and reliability of the Monash Women's Health Program Female Sexual Satisfaction Questionnaire
Publisher: Oxford University Press (OUP)
Date: 11-2008
DOI: 10.1111/J.1743-6109.2008.00967.X
Abstract: A validated questionnaire to assess the nature and quality of the recent female sexual experience and that can be employed to evaluate acute therapeutic effects does not exist. To validate an instrument with which researchers can evaluate the nature and quality of the female sexual experience within 24 hours of a sexual event. A cross-sectional questionnaire study in 349 sexually active community-based women, aged 20-65 years, who self-identified as being either satisfied or dissatisfied with their sexual life. Scores from the Monash Women's Health Program Female Sexual Satisfaction Questionnaire (MFSSQ), completed within 24 hours of sexual activity, on two occasions. Participants were 349 women who were sexually active at least once per fortnight, but not necessarily partnered. Almost equal groups of self-identified satisfied, dissatisfied, premenopausal, and postmenopausal women participated. Three hundred forty-five women (99%) completed one MFSSQ, and 326 women (94%) completed two separate questionnaires, each within 24 hours of a sexual event. Missing responses were few, good inter-item correlation was seen, and excellent reliability was demonstrated for most items, based on test-retest data. The questionnaire was able to discriminate well between sexually satisfied and dissatisfied women. The MFSSQ is a 12-item questionnaire specifically designed to assess the quality and nature of a recent sexual experience. It is easy and quick to administer, is reliable and valid, and has the potential to be used to assess the efficacy of acute interventions in the area of female sexual dysfunction.
Terahertz and conventional analysis of virus-like particle vaccines
Publisher: Elsevier BV
Date: 11-2009
Quaternary size distribution of soluble aggregates of glutathione-S-transferase-purified viral protein as determined by asymmetrical flow field flow fractionation and dynamic light scattering
Publisher: Elsevier BV
Date: 05-2008
DOI: 10.1016/J.CHROMA.2008.03.032
Abstract: Polyomavirus VP1 protein in pentamer form was expressed in E. coli and purified using glutathione-S-transferase (GST) affinity chromatography. Purified GST-tagged protein was found to exist as soluble aggregates with a size distribution of 1-52 tagged pentamers (340-1800 x 10(3)kDa), as determined by asymmetrical flow field flow fractionation with multiple angle light scattering (AFFFF-MALS). Aggregation did not inhibit tag removal by enzymatic cleavage, implying that the quaternary structure of the VP1 pentamers had been maintained. Elution gel filtration (EGF) was utilized to prepare a solution enriched with protein small enough to access resin pores (LMWe) as well as solution enriched with protein excluded from resin pores (HMWe). Material size distributions within both solutions were determined using AFFFF-MALS (radius of gyration LMWe: 5-10nm HMWe: 10-35 nm) and dynamic light scattering (DLS) (hydrodynamic diameter LMWe: 10-90 nm HMWe: 20-300 nm). DLS and AFFFF-MALS analysis of each fraction of affinity chromatography purified material identified the elution profiles of large and small aggregate structures. DLS readings of all fractions were significantly affected by the presence of high molecular weight aggregates, with Z-average hydrodynamic diameter values reflecting the mass ratio of large and small aggregate structures in a solution. The methods utilized in this study have the potential to be used during chromatographic purification of all proteins that exist as soluble aggregates to determine size distribution. The finding that GST-tagged viral proteins exist as soluble aggregates has implications for existing immunological studies that utilize them.
Evaluation of three adjuvants with respect to both adverse effects and the efficacy of antibody production to the Bm86 protein
Publisher: Springer Science and Business Media LLC
Date: 07-2017
DOI: 10.1007/S10493-017-0156-4
Abstract: Cattle tick infestations remain an important burden for farmers in tropical area like in New Caledonia. With the development of acaricide resistance, tick vaccines should be an attractive alternative to control ticks but their efficacy needs to be improved. In this study three adjuvants were studied in an experimental tick vaccine with a Bm86 protein to assess their performance in terms of antibody productions and adverse reactions following vaccinations. The water-in-oil adjuvant ISA 61 VG led to higher antibody titers compared to a water-in-oil-in-water adjuvant ISA 201 VG and an aqueous polymeric adjuvant Montanide Gel 01. Vaccinations with these three adjuvants did not produce severe general reaction but an increase in skin thickness was observed especially with both oil-based emulsions. These results indicated that the water-in-oil adjuvant is the most interesting to use for this vaccine but local adverse reactions remain an issue.
Affinity purification of viral protein having heterogeneous quaternary structure: Modeling the impact of soluble aggregates on chromatographic performance
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1016/J.CHROMA.2009.05.082
Abstract: Prokaryote-expressed polyomavirus structural protein VP1 with an N-terminal glutathione-S-transferase tag (GST-VP1) self-assembles into pentamer structures that further organize into soluble aggregates of variable size (3.4 x 10(2)-1.8 x 10(4)kDa) [D.I. Lipin, L.H.L. Lua, A.P.J. Middelberg, J. Chromatogr. A 1190 (2008) 204]. The adsorption mechanism for the full range of GST-VP1 soluble aggregates was described assuming a dual-component model [T.Y. Gu, G.J. Tsai, G.T. Tsao, AICHE J. 37 (1991) 1333], with components differentiated by size, and hence pore accessibility, rather than by protein identity. GST-VP1 protein was separated into two component groups: aggregates small enough to access resin pores (LMW: 3.4 x 10(2)-1.4 x 10(3)kDa) and aggregates excluded from the resin pores (HMW: 9.0 x 10(2)-1.8 x 10(4)kDa). LMW aggregates bound to resin at a higher saturation concentration (29.7 g L(-1)) than HMW aggregates (13.3 g L(-1)), while the rate of adsorption of HMW aggregates was an order of magnitude higher than for LMW aggregates. The model was used to predict both batch and packed bed adsorption of GST-VP1 protein in solutions with known concentrations of HMW and LMW aggregates to Glutathione Sepharose HP resin. Asymmetrical flow field flow fractionation with UV absorbance was utilized in conjunction with adsorption experimentation to show that binding of HMW aggregates to the resin was strong enough to withstand model-predicted displacement by LMW aggregates. High pore concentrations of LMW aggregates were also found to significantly inhibit the diffusion rate of further protein in the resin pores. Additional downstream processing experimentation showed that enzymatic cleavage of LMW aggregates to remove GST tags yields more un-aggregated VP1 pentamers than enzymatic cleavage of HMW aggregates. This model can be used to enhance the chromatographic capture of GST-VP1, and suggests an approach for modeling chromatographic purification of proteins that have a range of quaternary structures, including soluble aggregates.
Encapsulation of DNA and non-viral protein changes the structure of murine polyomavirus virus-like particles
Publisher: Springer Science and Business Media LLC
Date: 11-2008
DOI: 10.1007/S00705-008-0220-9
Abstract: Asymmetrical-flow field flow fractionation with multiple-angle light scattering (AFFFF-MALS) was, for the first time, used to characterize the size of murine polyomavirus virus-like particles (MPV VLPs) packaged with either insect cell genomic DNA or non-viral protein. Encapsidation of both genomic DNA and non-viral protein were found to cause a contraction in VLP radii of gyration by approximately 1 nm. Non-viral protein packaged into VLPs consisted of a series of glutathione-S-transferase, His and S tags attached to the N-terminal end of the MPV structural protein VP2 (M(r) = 67108). Transmission electron microscopy analysis of MPV VLPs packaging non-viral protein suggested that VLPs grew in diameter by approximately 5 nm, highlighting the differences between this invasive technique and the relatively non-invasive AFFFF-MALS technique. Encapsulation of non-viral protein into MPV VLPs was found to prevent co-encapsidation of genomic DNA. Further investigation into why this occurred led to the discovery that encapsulation of non-viral protein alters the nuclear localization of MPV VLPs during in vivo assembly. VLPs were relocated away from the ring zone and the nuclear membrane towards the centre of the nucleus amongst the virogenic stroma. The change in nuclear localization away from the site where VLP assembly usually occurs is a likely reason why encapsidation of genomic DNA did not take place.
Design strategies to address the effect of hydrophobic epitope on stability andin vitroassembly of modular virus-like particle
Publisher: Wiley
Date: 13-06-2016
DOI: 10.1002/PRO.2953
Vastus medialis cross-sectional area is associated with patella cartilage defects and bone volume in healthy women
Publisher: Elsevier BV
Date: 08-2008
DOI: 10.1016/J.JOCA.2007.11.011
Abstract: Although vastus medialis and vastus lateralis are important muscular determinants of patellofemoral joint function, it is unclear how these muscles relate to the structure of the patellofemoral joint. The aim of this cross-sectional study was to determine the relationship between the vasti muscles and patella cartilage volume and defects and patella bone volume. One hundred and seventy-five women, aged 40-67 years, with no knee pain or clinical lower-limb disease had magnetic resonance imaging (MRI) of their dominant knee. The cross-sectional areas of the distal vastus medialis and lateralis were measured 37.5mm superior to the quadriceps tendon insertion at the proximal pole of the patella. Patella cartilage volume and defects and patella bone volume were measured from these images using validated methods. There was no significant association between the distal vastus medialis cross-sectional area and patella cartilage volume. For every 1mm(2) increase in the distal vastus medialis cross-sectional area, there was an associated increased risk of patella cartilage defects [odds ratio (OR): 1.2 95% confidence interval (CI) 1.004, 1.5 P=0.05], and an associated increase in patella bone volume (OR: 3.9 95% CI 2.0, 5.8 P<0.001) after adjustment for potential confounders. There was no significant relationship between vastus lateralis cross-sectional area and measures of patella cartilage or bone. An increased cross-sectional area of the distal portion of the vastus medialis muscle is associated with an increased risk of patella cartilage defects, and an increase in patella bone volume among healthy women. Although these results need to be confirmed in longitudinal studies, they suggest that an increase in the distal vastus medialis cross-sectional area is associated with structural change at the patellofemoral joint.
Integrated molecular and bioprocess engineering for bacterially produced immunogenic modular virus‐like particle vaccine displaying 18 kDa rotavirus antigen
Publisher: Wiley
Date: 17-08-2016
DOI: 10.1002/BIT.26068
Abstract: A high global burden of rotavirus disease and the unresolved challenges with the marketed rotavirus vaccines, particularly in the developing world, have ignited efforts to develop virus-like particle (VLP) vaccines for rotavirus. While rotavirus-like particles comprising multiple viral proteins can be difficult to process, modular VLPs presenting rotavirus antigenic modules are promising alternatives in reducing process complexity and cost. In this study, integrated molecular and bioprocess engineering approaches were used to simplify the production of modular murine polyomavirus capsomeres and VLPs presenting a rotavirus 18 kDa VP8* antigen. A single construct was generated for dual expression of non-tagged murine polyomavirus capsid protein VP1 and modular VP1 inserted with VP8*, for co-expression in Escherichia coli. Co-expressed proteins assembled into pentameric capsomeres in E. coli. A selective salting-out precipitation and a polishing size exclusion chromatography step allowed the recovery of stable modular capsomeres from cell lysates at high purity, and modular capsomeres were successfully translated into modular VLPs when assembled in vitro. Immunogenicity study in mice showed that modular capsomeres and VLPs induced high levels of VP8*-specific antibodies. Our results demonstrate that a multipronged synthetic biology approach combining molecular and bioprocess engineering enabled simple and low-cost production of highly immunogenic modular capsomeres and VLPs presenting conformational VP8* antigenic modules. This strategy potentially provides a cost-effective production route for modular capsomere and VLP vaccines against rotavirus, highly suitable to manufacturing economics for the developing world. Biotechnol. Bioeng. 2017 : 397-406. © 2016 Wiley Periodicals, Inc.
Possible roles for Munc18-1 domain 3a and Syntaxin1 N-peptide and C-terminal anchor in SNARE complex formation
Publisher: Proceedings of the National Academy of Sciences
Date: 30-12-2011
Abstract: Munc18-1 and Syntaxin1 are essential proteins for SNARE-mediated neurotransmission. Munc18-1 participates in synaptic vesicle fusion via dual roles: as a docking/chaperone protein by binding closed Syntaxin1, and as a fusion protein that binds SNARE complexes in a Syntaxin1 N-peptide dependent manner. The two roles are associated with a closed–open Syntaxin1 conformational transition. Here, we show that Syntaxin N-peptide binding to Munc18-1 is not highly selective, suggesting that other parts of the SNARE complex are involved in binding to Munc18-1. We also find that Syntaxin1, with an N peptide and a physically anchored C terminus, binds to Munc18-1 and that this complex can participate in SNARE complex formation. We report a Munc18-1–N-peptide crystal structure that, together with other data, reveals how Munc18-1 might transit from a conformation that binds closed Syntaxin1 to one that may be compatible with binding open Syntaxin1 and SNARE complexes. Our results suggest the possibility that structural transitions occur in both Munc18-1 and Syntaxin1 during their binary interaction. We hypothesize that Munc18-1 domain 3a undergoes a conformational change that may allow coiled-coil interactions with SNARE complexes.
Molecular Energetics in the Capsomere of Virus-Like Particle Revealed by Molecular Dynamics Simulations
Publisher: American Chemical Society (ACS)
Date: 26-04-2013
DOI: 10.1021/JP311170W
Abstract: Virus-like particles (VLPs) are highly organized nanoparticles that have great potential in vaccinology, gene therapy, drug delivery, and materials science. However, the application of VLPs is hindered by obstacles in their design and production due to low efficiency of self-assembly. In the present study, all-atom (AA) molecular dynamics (MD) simulations coupled with the molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) method are utilized to examine the molecular interactions in the capsomere of a murine polyomavirus (MPV) VLP. It is found that both low ionic strength and the intracapsomere disulfide bonds are favorable for maintaining a stable capsomere. Simulation results examining the effects of solution conditions on the stabilization of a capsomere were verified by calorimetry experiments. Simulation results of free energy decomposition indicate that hydrophobic interaction is favorable for the formation of a capsomere, whereas electrostatic interaction is unfavorable. With increasing ionic strength, the dominant interaction for the stabilization of a capsomere changes from hydrophobic to electrostatic. By comprehensive analyses, the key amino acid residues (hot spots) in VP1 protein aiding formation of a capsomere in different solution conditions have been identified. These results provide molecular insights into the stabilization of building blocks for VLP and are expected to have implications in their partitioning between the correct and off-pathway reactions in VLP assembly.
Biomolecular engineering of virus-like particles aided by computational chemistry methods
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CS00526D
Abstract: Multi-scale investigation of VLP self-assembly aided by computational methods is facilitating the design, redesign, and modification of functionalized VLPs.
Antibody-Binding, Antifouling Surface Coatings Based on Recombinant Expression of Zwitterionic EK Peptides
Publisher: American Chemical Society (ACS)
Date: 25-05-2019
DOI: 10.1021/ACS.LANGMUIR.8B00810
Abstract: Development of antifouling films which selectively capture or target proteins of interest is essential for controlling interactions at the "bio/nano" interface. However, in order to synthesize biofunctional films from synthetic polymers that incorporate chemical "motifs" for surface immobilization, antifouling, and oriented biomolecule attachment, multiple reaction steps need to be carried out at the solid/liquid interface. EKx is a zwitterionic peptide that has previously been shown to have excellent antifouling properties. In this study, we recombinantly expressed EKx peptides and genetically encoded both surface attachment and antibody-binding motifs, before characterizing the resultant biopolymers by traditional methods. These peptides were then immobilized to organosilica nanoparticles for binding IgG, and subsequently capturing dengue NS1 as a model antigen from serum-containing solution. We found that a mixed layer of a short peptide (4.9 kDa) "backfilled" with a longer peptide terminated with an IgG-binding Z-domain (18 kDa) demonstrated selective capture of dengue NS1 protein down to ∼10 ng mL
The safety of 52 weeks of oral DHEA therapy for postmenopausal women
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1016/J.MATURITAS.2009.03.020
Abstract: The aim of this study was to evaluate the safety of 52 weeks of DHEA 50mg daily oral dose given to postmenopausal women with low libido to improve sexual function. 93 postmenopausal women were enrolled in a 52-week randomised, double-blind, placebo-controlled trial and received either DHEA 50mg or placebo (PL) daily. The effects of DHEA versus placebo on lipid profile, insulin-glucose homeostasis and the endomentrium were assessed over 52 weeks. Oral DHEA, 50mg/day, was not associated with any effects on blood lipids or insulin resistance. The pattern of breakthrough bleeding did not substantially differ between the DHEA and PL groups and no significant adverse endometrial effects were apparent. The use of 50mg oral DHEA did not significantly alter lipid profile, insulin sensitivity or adversely affect the endometrium in postmenopausal women.
Yeast-based bioproduction of disulfide-rich peptides and their cyclization via asparaginyl endopeptidases
Publisher: Springer Science and Business Media LLC
Date: 17-02-2021
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