ORCID Profile
0000-0002-4910-7605
Current Organisations
The University of Auckland
,
AgResearch Ltd Grasslands Research Centre
,
AgResearch Ltd
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: American Chemical Society (ACS)
Date: 10-03-2009
DOI: 10.1021/BM801394S
Abstract: Polyhydroxyalkanoates (PHAs) are naturally occurring organic polyesters that are of interest for industrial and biomedical applications. These polymers are synthesized by most bacteria in times of unbalanced nutrient availability from a variety of substrates and they are deposited intracellularly as insoluble spherical inclusions or PHA granules. The granules consist of a polyester core, surrounded by a boundary layer with embedded or attached proteins that include the PHA synthase, phasins, depolymerizing enzymes, and regulatory proteins. Apart from ongoing industrial interest in the material PHA, more recently there has also been increasing interest in applications of the PHA granules as nano-/micro-beads after it was conceived that fusions to the granule associated proteins (GAPs) provide a way to immobilize target proteins at the granule surface. This review gives an overview of PHA granules in general, including biogenesis and GAPs, and focuses on their potential use as nano-/micro-beads in biotechnological and biomedical applications.
Publisher: Elsevier BV
Date: 03-05-2010
DOI: 10.1016/J.JBIOTEC.2010.02.021
Abstract: Polyhydroxyalkanoates are biodegradable biocompatible polymers naturally produced by various bacteria and archaea. Biotechnological production in transgenic plants has already been demonstrated with efficient polyhydroxybutyrate production requiring targeting of the enzymes to the chloroplasts. Three enzymes are required to establish the polyhydroxybutyrate biosynthesis pathway in non-naturally producing microorganisms or plants. To facilitate production of biopolyesters in plants, a gene encoding a translational fusion of the polyhydroxybutyrate biosynthesis enzymes PhaA (beta-ketothiolase), PhaB (acetoacetyl-CoA reductase) and PhaC (PHA synthase) was constructed. Escherichia coli harboring a plasmid encoding this fusion protein (PhaA-PhaB-PhaC) under control of the lac promoter accumulated polyhydroxybutyrate contributing to 0.4% (w/w) of cellular dry weight. Insertion of an extended linker between PhaA and PhaB increased polyhydroxybutyrate accumulation to 3.9% (w/w) of cellular dry weight. Introduction of a second plasmid encoding PhaA and PhaB restored polyhydroxybutyrate accumulation to wildtype levels of about 35% (w/w) of cellular dry weight suggesting that the functions of PhaA and/or PhaB were limiting factors. Deletion of PhaA in trans led to significantly reduced polyhydroxybutyrate production suggesting that the PhaA activity in the fusion protein is reduced. This study showed that a single-chain translational fusion protein comprising the three enzymes essential for polyhydroxybutyrate synthesis can be engineered which will strongly facilitate the establishment of recombinant polyhydroxybutyrate production organisms particularly requiring targeting to sub-cellular compartments such as the chloroplasts in plants.
Publisher: Springer Science and Business Media LLC
Date: 17-02-2018
Publisher: Elsevier BV
Date: 10-2013
Publisher: Springer Science and Business Media LLC
Date: 18-09-2009
DOI: 10.1007/S10529-008-9836-9
Abstract: Microbial polyester inclusions have previously been demonstrated to be applicable as versatile beads outside the bacterial cell. Engineering of proteins selectively binding to the polyester inclusions was conceived to produce polyester beads simultaneously displaying two protein-based functions suitable for applications in, for ex le, fluorescence activated cell sorting (FACS). The polyester synthase and the phasin protein were fused to the green fluorescent protein (GFP) and the murine myelin oligodendrocyte glycoprotein (MOG), respectively, or GFP and MOG were fused to the N- and C-terminus, respectively, of only the phasin. In both cases, fusion proteins were found to be attached to isolated polyester inclusions while displaying both functionalities per bead. Functionalities at the bead surface were assessed by ELISA, FACS and fluorescence microscopy. The respective double fusion protein was identified by peptide fingerprinting using MALDI-TOF/MS.
Publisher: MDPI AG
Date: 09-02-2019
DOI: 10.3390/NU11020364
Abstract: Complementary feeding transitions infants from a milk‐based diet to solid foods, providing essential nutrients to the infant and the developing gut microbiome while influencing immune development. Some of the earliest microbial colonisers readily ferment select oligosaccharides, influencing the ongoing establishment of the microbiome. Non‐digestible oligosaccharides in prebiotic‐supplemented formula and human milk oligosaccharides promote commensal immune‐modulating bacteria such as Bifidobacterium, which decrease in abundance during weaning. Incorporating complex, bifidogenic, non‐digestible carbohydrates during the transition to solid foods may present an opportunity to feed commensal bacteria and promote balanced concentrations of beneficial short chain fatty acid concentrations and vitamins that support gut barrier maturation and immunity throughout the complementary feeding window.
Publisher: CABI Publishing
Date: 25-09-2013
Abstract: Epidemiological studies have shown an association between the consumption of cruciferous vegetables and a reduced risk of certain types of cancers, in particular, pancreatic, bladder and colorectal. This is thought to be the result of the conversion of glucosinolates (GSLs) present in the vegetables into bioactive isothiocyanates (ITCs) that in turn stimulate a host response involving detoxification pathways. Conversion of GSLs is catalysed by the enzyme myrosinase, co-produced by the plant but stored in separate tissue compartments and brought together when the tissue is damaged. Myrosinase activity can be lost during storage of vegetables and is often inactivated by cooking. In the absence of active plant myrosinase the host's gut bacteria are capable of carrying out a myrosinase-like activity on GSLs in the lower gut. Several micro-organisms are known to be capable of metabolizing GSLs leading to the production of ITCs and nitriles, and this review examines the bacterial biotransformation of GSLs and a role for the microbiota in their biotransformation.
Publisher: Wiley
Date: 15-04-2009
DOI: 10.1002/9780470054581.EIB129
Abstract: Over the past few decades, there has been a growing awareness of the potential uses of biodegradable polymers in biotechnology and medicine. In particular, micro‐ and nano‐sized particles which are made from natural resources, exhibiting biodegradability, biocompatibility, and low toxicity have been the subject of intense research and development in many areas. Apart from their beneficial material properties, these particles allow variations in structure and composition to be designed, thereby tailoring them for specific applications. This review presents a broad overview of the main categories of biopolyester particles described in the literature, and putting emphasis on the composition and preparation of each group, followed by the wide variety of applications and potential uses described to date.
Publisher: American Dairy Science Association
Date: 11-2022
Publisher: Springer Science and Business Media LLC
Date: 20-03-2018
Publisher: American Chemical Society (ACS)
Date: 15-03-2013
DOI: 10.1021/JF305442J
Abstract: Glucosinolates from the genus Brassica can be converted into bioactive compounds known to induce phase II enzymes, which may decrease the risk of cancers. Conversion via hydrolysis is usually by the brassica enzyme myrosinase, which can be inactivated by cooking or storage. We examined the potential of three beneficial bacteria, Lactobacillus plantarum KW30, Lactococcus lactis subsp. lactis KF147, and Escherichia coli Nissle 1917, and known myrosinase-producer Enterobacter cloacae to catalyze the conversion of glucosinolates in broccoli extract. Enterobacteriaceae consumed on average 65% glucoiberin and 78% glucoraphanin, transforming them into glucoiberverin and glucoerucin, respectively, and small amounts of iberverin nitrile and erucin nitrile. The lactic acid bacteria did not accumulate reduced glucosinolates, consuming all at 30-33% and transforming these into iberverin nitrile, erucin nitrile, sulforaphane nitrile, and further unidentified metabolites. Adding beneficial bacteria to a glucosinolate-rich diet may increase glucosinolate transformation, thereby increasing host exposure to bioactives.
Publisher: American Diabetes Association
Date: 12-08-2018
DOI: 10.2337/DC18-0777
Abstract: Dysbiosis of the gut microbiota has been linked to disease pathogenesis in type 1 diabetes, yet the functional consequences to the host of this dysbiosis are unknown. We investigated the functional interactions between the microbiota and the host associated with type 1 diabetes disease risk. We performed a cross-sectional analysis of stool s les from subjects with recent-onset type 1 diabetes (n = 33), islet autoantibody–positive subjects (n = 17), low-risk autoantibody-negative subjects (n = 29), and healthy subjects (n = 22). Metaproteomic analysis was used to identify gut- and pancreas-derived host and microbial proteins, and these data were integrated with sequencing-based microbiota profiling. Both human (host-derived) proteins and microbial-derived proteins could be used to differentiate new-onset and islet autoantibody–positive subjects from low-risk subjects. Significant alterations were identified in the prevalence of host proteins associated with exocrine pancreas output, inflammation, and mucosal function. Integrative analysis showed that microbial taxa associated with host proteins involved in maintaining function of the mucous barrier, microvilli adhesion, and exocrine pancreas were depleted in patients with new-onset type 1 diabetes. These data support that patients with type 1 diabetes have increased intestinal inflammation and decreased barrier function. They also confirmed that pancreatic exocrine dysfunction occurs in new-onset type 1 diabetes and show for the first time that this dysfunction is present in high-risk in iduals before disease onset. The data identify a unique type 1 diabetes–associated signature in stool that may be useful as a means to monitor disease progression or response to therapies aimed at restoring a healthy microbiota.
Publisher: Springer Science and Business Media LLC
Date: 21-09-2018
Publisher: Springer Science and Business Media LLC
Date: 04-01-2007
Abstract: Fluorescence activated cell sorting (FACS) is a powerful technique for the qualitative and quantitative detection of biomolecules used widely in both basic research and clinical diagnostic applications. Beads displaying a specific antigen are used to bind antibodies which are then fluorescently labelled using secondary antibodies. As the in idual suspension bead passes through the sensing region of the FACS machine, fluorescent signals are acquired and analysed. Currently, antigens are tediously purified and chemically cross-linked to preformed beads. Purification and coupling of proteins often renders them inactive and they will not be displayed in its native configuration. As an alternative, we genetically engineered Escherichia coli to produce biopolyester (polyhdroxyalkanoate=PHA) granules displaying diagnostically relevant antigens in their native conformation and suitable for FACS analysis. Hybrid genes were constructed, which encode either the mouse interleukin-2 (IL2) or the myelin oligodendrocyte glycoprotein (MOG) fused via an enterokinase site providing linker region to the C terminus of the PHA granule associated protein PhaP, respectively. The hybrid genes were expressed in PHA-accumulating recombinant E. coli . MOG and IL2 fusion proteins were abundantly attached to PHA granules and were identified by MALDI-TOF/MS analysis and N terminal sequencing. A more abundant second fusion protein of either MOG or IL2 resulted from an additional N terminal fusion, which did surprisingly not interfere with attachment to PHA granule. PHA granules displaying either IL2 or MOG were used for FACS using monoclonal anti-IL2 or anti-MOG antibodies conjugated to a fluorescent dye. FACS analysis showed significant and specific binding of respective antibodies. Enterokinase treatment of IL2 displaying PHA granules enabled removal of IL2 as monitored by FACS analysis. Mice were immunized with either MOG or OVA (ovalbumin) and the respective sera were analysed using MOG-displaying PHA granules and FACS analysis showing a specific and sensitive detection of antigen-specific antibodies within a wide dynamic range. E. coli can be genetically engineered to produce PHA granules displaying correctly folded eukaryotic proteins and which can be applied as beads in FACS based diagnostics. Since PHA granule formation and protein attachment occurs in one step already inside the bacterial cell, microbial production could be a cheap and efficient alternative to commercial beads.
Publisher: Public Library of Science (PLoS)
Date: 14-07-2022
DOI: 10.1371/JOURNAL.PONE.0270213
Abstract: The infant gut microbiome progresses in composition and function during the introduction of solid foods throughout the first year of life. The purpose of this study was to characterize changes in healthy infant gut microbiome composition, metagenomic functional capacity, and associated metabolites over the course of the complementary feeding period. Fecal s les were obtained at three ‘snapshot’ timepoints from infants participating in the ‘Nourish to Flourish’ pilot study: before the introduction of solid foods at approximately 4 months of age, after introducing solid foods at 9 months of age, and after continued diet ersification at 12 months of age. KEGG and taxonomy assignments were correlated with LC-MS metabolomic profiles to identify patterns of co-abundance. The composition of the microbiome ersified during the first year of life, while the functional capacity present in the gut microbiome remained stable. The introduction of solid foods between 4 and 9 months of age corresponded to a larger magnitude of change in relative abundance of sequences assigned to KEGG pathways and taxonomic assignments, as well as to stronger correlations with metabolites, compared to the magnitude of changes and number of correlations seen during continued diet ersification between 9 and 12 months of age. Changes in aqueous fecal metabolites were more strongly correlated with KEGG pathway assignments, while changes in lipid metabolites associated with taxonomic assignments, particularly between 9 and 12 months of age. This study establishes trends in microbiome composition and functional capacity occurring during the complementary feeding period and identifies potential metabolite targets for future investigations.
Publisher: Wiley
Date: 09-10-2018
DOI: 10.1111/IMCB.12201
Abstract: The microbial community making up the gut microbiota can profoundly influence intestinal homeostasis and immune system development, and is believed to influence the development of complex diseases including type 1 diabetes (T1D). T1D susceptible nonobese diabetic ( NOD ) mice have been shown to harbor a distinct microbiota to disease‐protected mice. We hypothesized that the T1D susceptible genetic background of NOD mice would be resistant to the introduction of a C57 BL /6‐derived microbiota. NOD and C57 BL /6 mice were cohoused either continually from birth, from birth until weaning or from weaning onwards, allowing transfer of microbiota between the mice. Cohousing NOD with C57 BL /6 mice from before birth, resulted in moderate changes to the gut microbiota, whereas initiating cohousing at weaning only led to minimal changes. Terminating cohousing at weaning reduced the changes in the microbiota composition. However, diabetes onset was not significantly delayed and there was no reduction in intestinal inflammation or the proportion of regulatory T cells in the cohoused NOD mice. However, insulin but not islet‐specific glucose‐6‐phosphatase catalytic subunit‐related protein‐specific CD 8 + T cells were reduced by cohousing suggesting an epitope‐specific modulation of the autoreactive response by the gut microbiota. These results suggest that the T1D susceptible genetic background of the NOD mouse was resistant to the introduction of a C57 BL /6‐derived microbiota.
Publisher: American Society for Microbiology
Date: 11-2006
DOI: 10.1128/AEM.01014-06
Abstract: The immunoglobulin G (IgG) binding ZZ domain of protein A from Staphylococcus aureus was fused to the N terminus of the polyhydroxyalkanoate (PHA) synthase from Cupriavidus necator . The fusion protein was confirmed by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry and mediated formation of ZZ domain-displaying PHA granules in recombinant Escherichia coli . The IgG binding capacity of isolated granules was assessed using enzyme-linked immunosorbent assay and could be enhanced by the overproduction of the ZZ-PHA synthase. ZZ-PHA granules enabled efficient purification of IgG from human serum.
No related grants have been discovered for Jane Mullaney.