Journal Articles
Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915
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Item Impact of cell wall polysaccharide modifications on the performance of Pichia pastoris: novel mutants with enhanced fitness and functionality for bioproduction applications.(BioMed Central Ltd, 2024-02-17) Cheng B; Yu K; Weng X; Liu Z; Huang X; Jiang Y; Zhang S; Wu S; Wang X; Hu XBACKGROUND: Pichia pastoris is a widely utilized host for heterologous protein expression and biotransformation. Despite the numerous strategies developed to optimize the chassis host GS115, the potential impact of changes in cell wall polysaccharides on the fitness and performance of P. pastoris remains largely unexplored. This study aims to investigate how alterations in cell wall polysaccharides affect the fitness and function of P. pastoris, contributing to a better understanding of its overall capabilities. RESULTS: Two novel mutants of GS115 chassis, H001 and H002, were established by inactivating the PAS_chr1-3_0225 and PAS_chr1-3_0661 genes involved in β-glucan biosynthesis. In comparison to GS115, both modified hosts exhibited a looser cell surface and larger cell size, accompanied by faster growth rates and higher carbon-to-biomass conversion ratios. When utilizing glucose, glycerol, and methanol as exclusive carbon sources, the carbon-to-biomass conversion rates of H001 surpassed GS115 by 10.00%, 9.23%, and 33.33%, respectively. Similarly, H002 exhibited even higher increases of 32.50%, 12.31%, and 53.33% in carbon-to-biomass conversion compared to GS115 under the same carbon sources. Both chassis displayed elevated expression levels of green fluorescent protein (GFP) and human epidermal growth factor (hegf). Compared to GS115/pGAPZ A-gfp, H002/pGAPZ A-gfp showed a 57.64% higher GFP expression, while H002/pPICZα A-hegf produced 66.76% more hegf. Additionally, both mutant hosts exhibited enhanced biosynthesis efficiencies of S-adenosyl-L-methionine and ergothioneine. H001/pGAPZ A-sam2 synthesized 21.28% more SAM at 1.14 g/L compared to GS115/pGAPZ A-sam2, and H001/pGAPZ A-egt1E obtained 45.41% more ERG at 75.85 mg/L. The improved performance of H001 and H002 was likely attributed to increased supplies of NADPH and ATP. Specifically, H001 and H002 exhibited 5.00-fold and 1.55-fold higher ATP levels under glycerol, and 6.64- and 1.47-times higher ATP levels under methanol, respectively, compared to GS115. Comparative lipidomic analysis also indicated that the mutations generated richer unsaturated lipids on cell wall, leading to resilience to oxidative damage. CONCLUSIONS: Two novel P. pastoris chassis hosts with impaired β-1,3-D-glucan biosynthesis were developed, showcasing enhanced performances in terms of growth rate, protein expression, and catalytic capabilities. These hosts exhibit the potential to serve as attractive alternatives to P. pastoris GS115 for various bioproduction applications.Item Slow and steady-small, but insufficient, changes in food and drink availability after four years of implementing a healthy food policy in New Zealand hospitals(BioMed Central Ltd, 2024-12) Mackay S; Rosin M; Kidd B; Gerritsen S; Shen S; Jiang Y; Te Morenga L; Ni Mhurchu CBACKGROUND: A voluntary National Healthy Food and Drink Policy (the Policy) was introduced in public hospitals in New Zealand in 2016. This study assessed the changes in implementation of the Policy and its impact on providing healthier food and drinks for staff and visitors in four district health boards between 1 and 5 years after the initial Policy introduction. METHODS: Repeat, cross-sectional audits were undertaken at the same eight sites in four district health boards between April and August 2017 and again between January and September 2021. In 2017, there were 74 retail settings audited (and 99 in 2021), comprising 27 (34 in 2021) serviced food outlets and 47 (65 in 2021) vending machines. The Policy's traffic light criteria were used to classify 2652 items in 2017 and 3928 items in 2021. The primary outcome was alignment with the Policy guidance on the proportions of red, amber and green foods and drinks (≥ 55% green 'healthy' items and 0% red 'unhealthy' items). RESULTS: The distribution of the classification of items as red, amber and green changed from 2017 to 2021 (p < 0.001) overall and in serviced food outlets (p < 0.001) and vending machines (p < 0.001). In 2021, green items were a higher proportion of available items (20.7%, n = 815) compared to 2017 (14.0%, n = 371), as were amber items (49.8%, n = 1957) compared to 2017 (29.2%, n = 775). Fewer items were classified as red in 2021 (29.4%, n = 1156) than in 2017 (56.8%, n = 1506). Mixed dishes were the most prevalent green items in both years, representing 11.4% (n = 446) of all items in 2021 and 5.5% (n = 145) in 2017. Fewer red packaged snacks (11.6%, n = 457 vs 22.5%, n = 598) and red cold drinks (5.2%, n = 205 vs 12.5%, n = 331) were available in 2021 compared to 2017. However, at either time, no organisation or setting met the criteria for alignment with the Policy (≥ 55% green items, 0% red items). CONCLUSIONS: Introduction of the Policy improved the relative healthiness of food and drinks available, but the proportion of red items remained high. More dedicated support is required to fully implement the Policy.Item Perception is reality: qualitative insights into how consumers perceive alcohol warning labels(Oxford University Press on behalf of the Medical Council on Alcohol, 2024-09) Kemper J; Rolleston A; Matthews K; Garner K; Lang B; Jiang Y; Ni Mhurchu C; Walker NAIMS: This study explores perspectives of on-pack alcohol warning labels, and how they might influence alcohol purchase and/or consumption behavior to inform culturally appropriate label design for effective behavior change. METHODS: New Zealand participants ≥18 years, who reported having purchased and consumed alcoholic beverages in the last month were recruited via a market research panel and grouped into 10 focus groups (n = 53) by ethnicity (general population, Māori, and Pacific peoples), age group, and level of alcohol consumption. Participants were shown six potential alcohol health warning labels, with design informed by relevant literature, label framework, and stakeholder feedback. Interviews were transcribed and analyzed via qualitative (directed) content analysis. RESULTS: Effective alcohol labels should be prominent, featuring large red and/or black text with a red border, combining text with visuals, and words like "WARNING" in capitals. Labels should contrast with bottle color, be easily understood, and avoid excessive text and confusing imagery. Participants preferred specific health outcomes, such as heart disease and cancer, increasing message urgency and relevance. Anticipated behavior change included reduced drinking and increased awareness of harms, but some may attempt to mitigate warnings by covering or removing labels. Contextual factors, including consistent design and targeted labels for different beverages and populations, are crucial. There was a strong emphasis on collective health impacts, particularly among Māori and Pacific participants. CONCLUSIONS: Our findings indicate that implementing alcohol warning labels, combined with comprehensive strategies like retail and social marketing campaigns, could effectively inform and influence the behavior of New Zealand's varied drinkers.Item Nourishing the Infant Gut Microbiome to Support Immune Health: Protocol of SUN (Seeding Through Feeding) Randomized Controlled Trial.(JMIR Publications, 2024-09-02) Wall CR; Roy NC; Mullaney JA; McNabb WC; Gasser O; Fraser K; Altermann E; Young W; Cooney J; Lawrence R; Jiang Y; Galland BC; Fu X; Tonkie JN; Mahawar N; Lovell AL; Ma SBackground: The introduction of complementary foods during the first year of life influences the diversity of the gut microbiome. How this diversity affects immune development and health is unclear. Objective: This study evaluates the effect of consuming kūmara or kūmara with added banana powder (resistant starch) compared to a reference control at 4 months post randomization on the prevalence of respiratory tract infections and the development of the gut microbiome. Methods: This study is a double-blind, randomized controlled trial of mothers and their 6-month-old infants (up to n=300) who have not yet started solids. Infants are randomized into one of 3 groups: control arm (C), standard kūmara intervention (K), and a kūmara intervention with added banana powder product (K+) to be consumed daily for 4 months until the infant is approximately 10 months old. Infants are matched for sex using stratified randomization. Data are collected at baseline (prior to commencing solid food) and at 2 and 4 months after commencing solid food (at around 8 and 10 months of age). Data and samples collected at each timepoint include weight and length, intervention adherence (months 2 and 4), illness and medication history, dietary intake (months 2 and 4), sleep (diary and actigraphy), maternal dietary intake, breast milk, feces (baseline and 4 months), and blood samples (baseline and 4 months). Results: The trial was approved by the Health and Disability Ethics Committee of the Ministry of Health, New Zealand (reference 20/NTA/9). Recruitment and data collection did not commence until January 2022 due to the COVID-19 pandemic. Data collection and analyses are expected to conclude in January 2024 and early 2025, respectively. Results are to be published in 2024 and 2025. Conclusions: The results of this study will help us understand how the introduction of a specific prebiotic complementary food affects the microbiota and relative abundances of the microbial species, the modulation of immune development, and infant health. It will contribute to the expanding body of research that aims to deepen our understanding of the connections between nutrition, gut microbiota, and early-life postnatal health. Trial Registration: Australian New Zealand Clinical Trials Registry ACTRN12620000026921; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=378654 International Registered Report Identifier (IRRID): DERR1-10.2196/56772 JMIR Res Protoc 2024;13:e56772Item Awareness, support, and opinions of healthy food and drink policies: a survey of staff and visitors in New Zealand healthcare organisations.(BioMed Central Ltd, 2024-08-12) Gerritsen S; Rosin M; Te Morenga L; Jiang Y; Kidd B; Shen S; Umali E; Mackay S; Ni Mhurchu CBackground In 2016, a voluntary National Healthy Food and Drink Policy (hereafter, “the Policy”) was released to encourage public hospitals in New Zealand to provide food and drink options in line with national dietary guidelines. Five years later, eight (of 20) organisations had adopted it, with several preferring to retain or update their own institutional-level version. This study assessed staff and visitors’ awareness and support for and against the Policy, and collected feedback on perceived food environment changes since implementation of the Policy. Methods Cross-sectional electronic and paper-based survey conducted from June 2021 to August 2022. Descriptive statistics were used to present quantitative findings. Free-text responses were analysed following a general inductive approach. Qualitative and quantitative findings were compared by level of implementation of the Policy, and by ethnicity and financial security of participants. Results Data were collected from 2,526 staff and 261 visitors in 19 healthcare organisations. 80% of staff and 56% of visitors were aware of the Policy. Both staff and visitors generally supported the Policy, irrespective of whether they were aware of it or not, with most agreeing that “Hospitals should be good role models.” Among staff who opposed the Policy, the most common reason for doing so was freedom of choice. The Policy had a greater impact, positive and negative, on Māori and Pacific staff, due to more frequent purchasing onsite. Most staff noticed differences in the food and drinks available since Policy implementation. There was positive feedback about the variety of options available in some hospitals, but overall 40% of free text comments mentioned limited choice. 74% of staff reported that food and drinks were more expensive. Low-income staff/visitors and shift workers were particularly impacted by reduced choice and higher prices for healthy options. Conclusions The Policy led to notable changes in the healthiness of foods and drinks available in NZ hospitals but this was accompanied by a perception of reduced value and choice. While generally well supported, the findings indicate opportunities to improve implementation of food and drink policies (e.g. providing more healthy food choices, better engagement with staff, and keeping prices of healthy options low) and confirm that the Policy could be expanded to other public workplaces.Item Effectiveness of a Sodium-Reduction Smartphone App and Reduced-Sodium Salt to Lower Sodium Intake in Adults With Hypertension: Findings From the Salt Alternatives Randomized Controlled Trial.(JMIR Publications, 2023-03-09) Eyles H; Grey J; Jiang Y; Umali E; McLean R; Te Morenga L; Neal B; Rodgers A; Doughty RN; Ni Mhurchu C; Buis LR; Eysenbach GBACKGROUND: Even modest reductions in blood pressure (BP) can have an important impact on population-level morbidity and mortality from cardiovascular disease. There are 2 promising approaches: the SaltSwitch smartphone app, which enables users to scan the bar code of a packaged food using their smartphone camera and receive an immediate, interpretive traffic light nutrition label on-screen alongside a list of healthier, lower-salt options in the same food category; and reduced-sodium salts (RSSs), which are an alternative to regular table salt that are lower in sodium and higher in potassium but have a similar mouthfeel, taste, and flavor. OBJECTIVE: Our aim was to determine whether a 12-week intervention with a sodium-reduction package comprising the SaltSwitch smartphone app and an RSS could reduce urinary sodium excretion in adults with high BP. METHODS: A 2-arm parallel randomized controlled trial was conducted in New Zealand (target n=326). Following a 2-week baseline period, adults who owned a smartphone and had high BP (≥140/85 mm Hg) were randomized in a 1:1 ratio to the intervention (SaltSwitch smartphone app + RSS) or control (generic heart-healthy eating information from The Heart Foundation of New Zealand). The primary outcome was 24-hour urinary sodium excretion at 12 weeks estimated via spot urine. Secondary outcomes were urinary potassium excretion, BP, sodium content of food purchases, and intervention use and acceptability. Intervention effects were assessed blinded using intention-to-treat analyses with generalized linear regression adjusting for baseline outcome measures, age, and ethnicity. RESULTS: A total of 168 adults were randomized (n=84, 50% per group) between June 2019 and February 2020. Challenges associated with the COVID-19 pandemic and smartphone technology detrimentally affected recruitment. The adjusted mean difference between groups was 547 (95% CI -331 to 1424) mg for estimated 24-hour urinary sodium excretion, 132 (95% CI -1083 to 1347) mg for urinary potassium excretion, -0.66 (95% CI -3.48 to 2.16) mm Hg for systolic BP, and 73 (95% CI -21 to 168) mg per 100 g for the sodium content of food purchases. Most intervention participants reported using the SaltSwitch app (48/64, 75%) and RSS (60/64, 94%). SaltSwitch was used on 6 shopping occasions, and approximately 1/2 tsp per week of RSS was consumed per household during the intervention. CONCLUSIONS: In this randomized controlled trial of a salt-reduction package, we found no evidence that dietary sodium intake was reduced in adults with high BP. These negative findings may be owing to lower-than-anticipated engagement with the trial intervention package. However, implementation and COVID-19-related challenges meant that the trial was underpowered, and it is possible that a real effect may have been missed. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12619000352101; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=377044 and Universal Trial U1111-1225-4471.Item Strain engraftment competition and functional augmentation in a multi-donor fecal microbiota transplantation trial for obesity(BioMed Central Ltd, 2021-12) Wilson BC; Vatanen T; Jayasinghe TN; Leong KSW; Derraik JGB; Albert BB; Chiavaroli V; Svirskis DM; Beck KL; Conlon CA; Jiang Y; Schierding W; Holland DJ; Cutfield WS; O'Sullivan JMBackground Donor selection is an important factor influencing the engraftment and efficacy of fecal microbiota transplantation (FMT) for complex conditions associated with microbial dysbiosis. However, the degree, variation, and stability of strain engraftment have not yet been assessed in the context of multiple donors. Methods We conducted a double-blinded randomized control trial of FMT in 87 adolescents with obesity. Participants were randomized to receive multi-donor FMT (capsules containing the fecal microbiota of four sex-matched lean donors) or placebo (saline capsules). Following a bowel cleanse, participants ingested a total of 28 capsules over two consecutive days. Capsules from individual donors and participant stool samples collected at baseline, 6, 12, and 26 weeks post-treatment were analyzed by shotgun metagenomic sequencing allowing us to track bacterial strain engraftment and its functional implications on recipients’ gut microbiomes. Results Multi-donor FMT sustainably altered the structure and the function of the gut microbiome. In what was effectively a microbiome competition experiment, we discovered that two donor microbiomes (one female, one male) dominated strain engraftment and were characterized by high microbial diversity and a high Prevotella to Bacteroides (P/B) ratio. Engrafted strains led to enterotype-level shifts in community composition and provided genes that altered the metabolic potential of the community. Despite our attempts to standardize FMT dose and origin, FMT recipients varied widely in their engraftment of donor strains. Conclusion Our study provides evidence for the existence of FMT super-donors whose microbiomes are highly effective at engrafting in the recipient gut. Dominant engrafting male and female donor microbiomes harbored diverse microbial species and genes and were characterized by a high P/B ratio. Yet, the high variability of strain engraftment among FMT recipients suggests the host environment also plays a critical role in mediating FMT receptivity. Trial registration The Gut Bugs trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12615001351505). Trial protocol The trial protocol is available at https://bmjopen.bmj.com/content/9/4/e026174.