Antioxidant Role for Lipid Droplets in a Stem Cell Niche of Drosophila.

Stem cells reside in specialized microenvironments known as niches. During Drosophila development, glial cells provide a niche that sustains the proliferation of neural stem cells (neuroblasts) during starvation. We now find that the glial cell niche also preserves neuroblast proliferation under conditions of hypoxia and oxidative stress. Lipid droplets that form in niche glia during oxidative stress limit the levels of reactive oxygen species (ROS) and inhibit the oxidation of polyunsaturated fatty acids (PUFAs). These droplets protect glia and also neuroblasts from peroxidation chain reactions that can damage many types of macromolecules. The underlying antioxidant mechanism involves diverting PUFAs, including diet-derived linoleic acid, away from membranes to the core of lipid droplets, where they are less vulnerable to peroxidation. This study reveals an antioxidant role for lipid droplets that could be relevant in many different biological contexts.

Anaplastic lymphoma kinase spares organ growth during nutrient restriction in Drosophila.

Developing animals survive periods of starvation by protecting the growth of critical organs at the expense of other tissues. Here, we use Drosophila to explore the as yet unknown mechanisms regulating this privileged tissue growth. As in mammals, we observe in Drosophila that the CNS is more highly spared than other tissues during nutrient restriction (NR). We demonstrate that anaplastic lymphoma kinase (Alk) efficiently protects neural progenitor (neuroblast) growth against reductions in amino acids and insulin-like peptides during NR via two mechanisms. First, Alk suppresses the growth requirement for amino acid sensing via Slimfast/Rheb/TOR complex 1. And second, Alk, rather than insulin-like receptor, primarily activates PI3-kinase. Alk maintains PI3-kinase signaling during NR as its ligand, Jelly belly (Jeb), is constitutively expressed from a glial cell niche surrounding neuroblasts. Together, these findings identify a brain-sparing mechanism that shares some regulatory features with the starvation-resistant growth programs of mammalian tumors.

Adipose triglyceride lipase protects renal cell endocytosis in a Drosophila dietary model of chronic kidney disease.

Obesity-related renal lipotoxicity and chronic kidney disease (CKD) are prevalent pathologies with complex aetiologies. One hallmark of renal lipotoxicity is the ectopic accumulation of lipid droplets in kidney podocytes and in proximal tubule cells. Renal lipid droplets are observed in human CKD patients and in high-fat diet (HFD) rodent models, but their precise role remains unclear. Here, we establish a HFD model in Drosophila that recapitulates renal lipid droplets and several other aspects of mammalian CKD. Cell type-specific genetic manipulations show that lipid can overflow from adipose tissue and is taken up by renal cells called nephrocytes. A HFD drives nephrocyte lipid uptake via the multiligand receptor Cubilin (Cubn), leading to the ectopic accumulation of lipid droplets. These nephrocyte lipid droplets correlate with endoplasmic reticulum (ER) and mitochondrial deficits, as well as with impaired macromolecular endocytosis, a key conserved function of renal cells. Nephrocyte knockdown of diglyceride acyltransferase 1 (DGAT1), overexpression of adipose triglyceride lipase (ATGL), and epistasis tests together reveal that fatty acid flux through the lipid droplet triglyceride compartment protects the ER, mitochondria, and endocytosis of renal cells. Strikingly, boosting nephrocyte expression of the lipid droplet resident enzyme ATGL is sufficient to rescue HFD-induced defects in renal endocytosis. Moreover, endocytic rescue requires a conserved mitochondrial regulator, peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC1α). This study demonstrates that lipid droplet lipolysis counteracts the harmful effects of a HFD via a mitochondrial pathway that protects renal endocytosis. It also provides a genetic strategy for determining whether lipid droplets in different biological contexts function primarily to release beneficial or to sequester toxic lipids.

Start small and let it build; a mixed-method evaluation of a school-based physical activity program, Kilometre Club.

BACKGROUND: Despite the benefits of physical activity, there is minimal research focusing on factors that influence real-world school-based physical activity programs. Kilometre (KM) Club is an Australian grassroots program which aims to increase physical activity in students through the completion of an outside walk or run at school. This small-scale pilot evaluation aimed to examine families, teachers and principals' perceptions of the benefits, enablers and barriers of KM Club. It also aimed to examine the effects of KM Club on student's physical activity levels during the school day. METHODS: Four regional New South Wales (NSW) primary schools participated in this study. 26 families, four teachers, and two principals from School A, C, B and D completed semi-structured interviews to understand their perceptions of KM Club. 21 students completed emotional state-scales to understand their emotions when participating in KM Club. 141 students from Schools B, C and D participated in step-count measures using accelerometers. RESULTS: Families, teachers and principals reported a range of benefits such as improved social connectedness, wellbeing, home and classroom behaviours, participation in sport and fitness levels. Enablers consisted of champion engagement, incentives, versatile facilities and integration with other school activities. Identified barriers included the weather and environment, program timing and health issues. Most students reported that participating in KM Club made them feel proud, confident and fantastic. School B reported a significant increase in students' daily step counts on KM Club days compared to non-KM Club days (+ 15%; p = 0.001), while School C reported no significant changes (-5%; p = 0.26). School D reported a significant increase in the number of daily steps taken by KM Club participants compared with non-KM club participants (+ 10%; p = 0.024). CONCLUSION: There is no one-size-fits-all approach to implementing school-based physical activity initiatives. However, it appears that flexible and adaptable factors are important to the successful implementation of school-based programs, such as KM Club. This study revealed a variety of self-reported health, wellbeing and educational benefits for students, as well as an increase in student's physical activity levels at 2 of the 3 schools participating in the quantitative data collection. This pilot evaluation may help to inform future design, implementation and scale-up of KM Club and school-based health promotion programs, potentially improving child health, wellbeing and educational outcomes. TRIAL REGISTRATION: (LNR223 - LNR/19/NCC/45).

Cladobotric Acids: Metabolites from Cultures of Cladobotryum sp., Semisynthetic Analogues and Antibacterial Activity.

Three new polyketide-derived natural products, cladobotric acids G-I (1-3), and six known metabolites (4, 5, 8-11) were isolated from fermentation of the fungus Cladobotryum sp. grown on rice. Their structures were elucidated by extensive spectroscopic methods. Two metabolites, cladobotric acid A (4) and pyrenulic acid A (10), were converted to a series of new products (12-20) by semisynthesis. The antibacterial activities of all these compounds were investigated against the Gram-positive pathogen Staphylococcus aureus including methicillin-susceptible (MSSA), methicillin-resistant and vancomycin-intermediate (MRSA/VISA), and heterogeneous vancomycin-intermediate (hVISA) strains. Results of these antibacterial assays revealed structural features of the unsaturated decalins important for biological activity.

A survey of teaching undergraduate neuroanatomy in the United Kingdom and Ireland.

BACKGROUND: Medical students' perception of neuroanatomy as a challenging topic has implications for referrals and interaction with specialists in the clinical neurosciences. Given plans to introduce a standardised Medical Licensing Assessment by 2023, it is important to understand the current framework of neuroanatomy education. This study aims to describe how neuroanatomy is taught and assessed in the UK and Ireland. METHODS: A structured questionnaire capturing data about the timing, methods, materials, assessment and content of the 2019/2020 neuroanatomy curriculum in the UK and Ireland medical schools. RESULTS: We received 24/34 responses. Lectures (96%) were the most widely used teaching method, followed by prosection (80%), e-learning (75%), tutorials/seminars (67%), problem-based learning (50%), case-based learning (38%), and dissection (30%). The mean amount of core neuroanatomy teaching was 29.3 hours. The most common formats of assessing neuroanatomical knowledge were multiple-choice exams, spot tests, and objective structured clinical exams. Only 37.5% schools required demonstration of core clinical competency relating to neuroanatomy. CONCLUSIONS: Our survey demonstrates variability in how undergraduate neuroanatomy is taught and assessed across the UK and Ireland. There is a role for development and standardisation of national undergraduate neuroanatomy curricula in order to improve confidence and attainment.

Core Steps to the Azaphilone Family of Fungal Natural Products.

Azaphilones are a family of polyketide-based fungal natural products that exhibit interesting and useful bioactivities. This minireview explores the literature on various characterised azaphilone biosynthetic pathways, which allows for a proposed consensus scheme for the production of the core azaphilone structure, as well as identifying early diversification steps during azaphilone biosynthesis. A consensus understanding of the core enzymatic steps towards a particular family of fungal natural products can aid in genome-mining experiments. Genome mining for novel fungal natural products is a powerful technique for both exploring chemical space and providing new insights into fungal natural product pathways.

Gaussian mixture model-based unsupervised nucleotide modification number detection using nanopore-sequencing readouts.

MOTIVATION: Nucleotide modification status can be decoded from the Oxford Nanopore Technologies nanopore-sequencing ionic current signals. Although various algorithms have been developed for nanopore-sequencing-based modification analysis, more detailed characterizations, such as modification numbers, corresponding signal levels and proportions are still lacking. RESULTS: We present a framework for the unsupervised determination of the number of nucleotide modifications from nanopore-sequencing readouts. We demonstrate the approach can effectively recapitulate the number of modifications, the corresponding ionic current signal levels, as well as mixing proportions under both DNA and RNA contexts. We further show, by integrating information from multiple detected modification regions, that the modification status of DNA and RNA molecules can be inferred. This method forms a key step of de novo characterization of nucleotide modifications, shedding light on the interpretation of various biological questions. AVAILABILITY AND IMPLEMENTATION: Modified nanopolish: https://github.com/adbailey4/nanopolish/tree/cigar_output. All other codes used to reproduce the results: https://github.com/hd2326/ModificationNumber. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Scale-up of the Physical Activity 4 Everyone (PA4E1) intervention in secondary schools: 24-month implementation and cost outcomes from a cluster randomised controlled trial.

BACKGROUND: Physical Activity 4 Everyone (PA4E1) is an evidence-based program effective at increasing adolescent physical activity (PA) and improving weight status. This study aimed to determine a) the effectiveness of an adapted implementation intervention to scale-up PA4E1 at 24-month follow-up, b) fidelity and reach, and c) the cost and cost-effectiveness of the implementation support intervention. METHODS: A cluster randomised controlled trial using a type III hybrid implementation-effectiveness design in 49 lower socio-economic secondary schools, randomised to a program (n = 24) or control group (n = 25). An adapted implementation intervention consisting of seven strategies was developed to support schools to implement PA4E1 over 24-months. The primary outcome was the proportion of schools implementing at least four of the 7 PA practices, assessed via computer assisted telephone interviews (CATI) with Head Physical Education Teachers. Secondary outcomes included the mean number of PA practices implemented, fidelity and reach, cost and cost-effectiveness. Logistic regression models assessed program effects. RESULTS: At baseline, no schools implemented four of the 7 PA practices. At 24-months, significantly more schools in the program group (16/23, 69.6%) implemented at least four of the 7 PA practices than the control group (0/25, 0%) (p < 0.001). At 24-months, program schools were implementing an average of 3.6 more practices than control schools (4.1 (1.7) vs. 0.5 (0.8), respectively) (P < 0.001). Fidelity and reach of the implementation intervention were high (> 75%). The total cost of the program was $415,112 AUD (2018) ($17,296 per school; $117.30 per student). CONCLUSIONS: The adapted implementation intervention provides policy makers and researchers with an effective and potentially cost-effective model for scaling-up the delivery of PA4E1 in secondary schools. Further assessment of sustainability is warranted. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12617000681358 prospectively registered 12th May 2017.

Scale-up of the Physical Activity 4 Everyone (PA4E1) intervention in secondary schools: 12-month implementation outcomes from a cluster randomized controlled trial.

BACKGROUND: 'Physical Activity 4 Everyone' (PA4E1) was an efficacious multi-component school-based physical activity (PA) program targeting adolescents. PA4E1 has seven PA practices. It is essential to scale-up, evaluate effectiveness and assess implementation of such programs. Therefore, the aim is to assess the impact of implementation support on school practice uptake of the PA4E1 program at 12 and 24 months. METHODS: A cluster randomised controlled trial, utilising a type III hybrid implementation-effectiveness design, was conducted in 49 randomly selected disadvantaged Australian Government and Catholic secondary schools. A blinded statistician randomly allocated schools to a usual practice control (n = 25) or the PA4E1 program group (n = 24), with the latter receiving seven implementation support strategies to support school PA practice uptake of the seven practices retained from the efficacy trial. The primary outcome was the proportion of schools adopting at least four of the seven practices, assessed via telephone surveys with Head Physical Education Teachers and analysed using exact logistic regression modelling. This paper reports the 12-month outcomes. RESULTS: Schools were recruited from May to November 2017. At baseline, no schools implemented four of the seven practices. At 12 months significantly more schools in the program group had implemented four of the seven practices (16/24, 66.7%) than the control group (1/25, 4%) (OR = 33.0[4.15-1556.4], p < 0.001). The program group implemented on average 3.2 (2.5-3.9) more practices than the control group (p < 0.001, mean 3.9 (SD 1.5) vs 0.7 (1.0)). Fidelity and reach of the implementation support intervention were high (both > 80%). CONCLUSIONS: Through the application of multiple implementation support strategies, secondary schools were able to overcome commonly known barriers to implement evidence based school PA practices. As such practices have been shown to result in an increase in adolescent PA and improvements in weight status, policy makers and practitioners responsible for advocating PA in schools should consider this implementation approach more broadly when working with schools. Follow-up is required to determine whether practice implementation is sustained. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12617000681358 registered 12th May 2017.

Adaptation of public health initiatives: expert views on current guidance and opportunities to advance their application and benefit.

While there is some guidance to support the adaptation of evidence-based public health interventions, little is known about adaptation in practice and how to best support public health practitioners in its operationalization. This qualitative study was undertaken with researchers, methodologists, policy makers and practitioners representing public health expert organizations and universities internationally to explore their views on available adaptation frameworks, elicit potential improvements to such guidance, and identify opportunities to improve implementation of public health initiatives. Participants attended a face to face workshop in Newcastle, Australia in October 2018 where World Café and focus group discussions using Appreciative Inquiry were undertaken. A number of limitations with current guidance were reported, including a lack of detail on 'how' to adapt, limited information on adaptation of implementation strategies and a number of structural issues related to the wording and ordering of elements within frameworks. A number of opportunities to advance the field was identified. Finally, a list of overarching principles that could be applied together with existing frameworks was generated and suggested to provide a practical way of supporting adaptation decisions in practice.

Patterns of emergency department use in rural and metropolitan New South Wales from 2012 to 2018.

OBJECTIVE: To explore the patterns of and investigate the factors associated with rises in emergency department presentations in rural and metropolitan New South Wales from 2012 to 2018. DESIGN: A retrospective descriptive study of de-identified data from the New South Wales Emergency Department Data Collection. SETTING: New South Wales, Australia. PARTICIPANTS: All individuals presenting to 99 New South Wales emergency departments, which continuously reported to the Emergency Department Data Collection between 2012 and 2018. A total of 2 166 449 presentations recorded throughout New South Wales in 2012 (rural 786 278; metropolitan 1 380 171) and 2 477 192 in 2018 (rural 861 761; metropolitan 1 615 431). MAIN OUTCOME MEASURES: Total emergency department presentations, plus Poisson regression modelled annual changes in emergency department presentations over the period 2012-2018. RESULTS: Growth in emergency department presentations outpaced population growth in both rural and metropolitan New South Wales between 2012 and 2018. The patterns of age-standardised rates of presentations were broadly similar between rural and metropolitan areas, with highest rates observed in the youngest (0-4 years) and oldest (85+ years) cohorts. The rural sample also displayed a distinct third peak in ages 15-39 years, and rates were higher across all age groups. Rural New South Wales displayed disproportionately higher emergency department presentations in the two most deprived socio-economic status quintiles. While rural New South Wales displayed significant reductions in triage category 5 (non-urgent cases) over time, the relative proportion remained approximately double that of metropolitan sites. CONCLUSIONS: There are differences between rural and metropolitan emergency department presentations relating to demographic factors, triage levels, acuity and admissions. Detailed local investigations are required to determine specific contextual issues that impact on emergency department demand.

An Improved Method for Measuring Absolute Metabolite Concentrations in Small Biofluid or Tissue Samples.

The measurement of absolute metabolite concentrations in small samples remains a significant analytical challenge. This is particularly the case when the sample volume is only a few microliters or less and cannot be determined accurately via direct measurement. We previously developed volume determination with two standards (VDTS) as a method to address this challenge for biofluids. As a proof-of-principle, we applied VDTS to NMR spectra of polar metabolites in the hemolymph (blood) of the tiny yet powerful genetic model Drosophila melanogaster. This showed that VDTS calculation of absolute metabolite concentrations in fed versus starved Drosophila larvae is more accurate than methods utilizing normalization to total spectral signal. Here, we introduce paired VDTS (pVDTS), an improved VDTS method for biofluids and solid tissues that implements the statistical power of paired control and experimental replicates. pVDTS utilizes new equations that also include a correction for dilution errors introduced by the variable surface wetness of solid samples. We then show that metabolite concentrations in Drosophila larvae are more precisely determined and logically consistent using pVDTS than using the original VDTS method. The refined pVDTS workflow described in this study is applicable to a wide range of different tissues and biofluids.

Relief of Neuropathic Pain Through Epidermal Growth Factor Receptor Inhibition: A Randomized Proof-of-Concept Trial.

OBJECTIVE: Case reports and a case series have described relief of neuropathic pain (NP) after treatment with epidermal growth factor receptor inhibitors (EGFR-Is). These observations are supported by preclinical findings. The aim of this trial was to explore a potential clinical signal supporting the therapeutic efficacy of EGFR-Is in NP. METHODS: In a proof-of-concept trial using a randomized, double-blind, placebo-controlled design, 14 patients with severe, chronic, therapy-resistant NP due to compressed peripheral nerves or complex regional pain syndrome were randomized to receive a single infusion of the EGFR-I cetuximab and placebo in crossover design, followed by a single open-label cetuximab infusion. RESULTS: The mean reduction in daily average pain scores three to seven days after single-blinded cetuximab infusion was 1.73 points (90% confidence interval [CI] = 0.80 to 2.66), conferring a 1.22-point greater reduction than placebo (90% CI = -0.10 to 2.54). Exploratory analyses suggested that pain reduction might be greater in the 14 days after treatment with blinded cetuximab than after placebo. The proportion of patients who reported ≥50% reduction in average pain three to seven days after cetuximab was 36% (14% after placebo), and comparison of overall pain reduction suggests a trend in favor of cetuximab. Skin rash (grade 1-2) was the most frequent side effect (12/14, 86%). CONCLUSIONS: This small proof-of-concept evaluation of an EGFR-I against NP did not provide statistical evidence of efficacy. However, substantial reductions in pain were reported, and confidence intervals do not rule out a clinically meaningful treatment effect. Evaluation of EGFR-I against NP therefore warrants further investigation.

Protocol for an effectiveness- implementation hybrid trial to assess the effectiveness and cost-effectiveness of an m-health intervention to decrease the consumption of discretionary foods packed in school lunchboxes: the 'SWAP IT' trial.

BACKGROUND: At a population level, small reductions in energy intake have the potential to contribute to a reduction in the prevalence of childhood obesity. In many school systems, there is the potential to achieve a reduction in energy intake through modest improvements in foods packed in children's school lunchboxes. This study will assess the effectiveness and cost-effectiveness of a multi-component intervention that uses an existing school-based communication application to reduce the kilojoule content from discretionary foods and drinks consumed by children from school lunchboxes whilst at school. METHODS: A Type I hybrid effectiveness-implementation cluster randomised controlled trial will be conducted in up to 36 primary schools in the Hunter New England, Central Coast and Mid North Coast regions of New South Wales, Australia. Designed using the Behaviour Change Wheel, schools will be randomly allocated to receive either a 5-month (1.5 school terms) multi-component intervention that includes: 1) school lunchbox nutrition guidelines; 2) curriculum lessons; 3) information pushed to parents via an existing school-based communication application and 4) additional parent resources to address common barriers to packing healthy lunchboxes or a control arm (standard school practices). The study will assess both child level dietary outcomes and school-level implementation outcomes. The primary trial outcome, mean energy (kJ) content of discretionary lunchbox foods packed in children's lunchboxes, will be assessed at baseline and immediately post intervention (5 months or 1.5 school terms). Analyses will be performed using intention to treat principles, assessing differences between groups via hierarchical linear regression models. DISCUSSION: This study will be the first fully powered randomised controlled trial internationally to examine the impact of an m-health intervention to reduce the mean energy from discretionary food and drinks packed in the school lunchbox. The intervention has been designed with scalability in mind and will address an important evidence gap which, if shown to be effective, has the potential to be applied at a population level. TRIAL REGISTRATION: Australian Clinical Trials Registry ACTRN:12618001731280 registered on 17/10/2018. Protocol Version 1.

A cluster randomised trial of an intervention to increase the implementation of physical activity practices in secondary schools: study protocol for scaling up the Physical Activity 4 Everyone (PA4E1) program.

BACKGROUND: The implementation of interventions at-scale is required to maximise population health benefits. 'Physical Activity 4 Everyone (PA4E1)' was a multi-component school-based program targeting adolescents attending secondary schools in low socio-economic areas. An efficacy trial of the intervention demonstrated an increase in students' mean minutes of moderate-to-vigorous physical activity (MVPA) per day and lower weight gain at low incremental cost. This study aims to assess the effectiveness and cost effectiveness of a multi-component implementation support intervention to improve implementation, at-scale, of the evidence based school physical activity (PA) practices of the PA4E1 program. Impact on student PA levels and adiposity will also be assessed, in addition to the cost of implementation. METHODS: A cluster randomised controlled trial, utilising an effectiveness-implementation hybrid design, will be conducted in up to 76 secondary schools located in lower socio-economic areas across four health districts in New South Wales (NSW), Australia. Schools will be randomly allocated to a usual practice control arm or a multi-component implementation support intervention to embed the seven school PA practices of the PA4E1 program. The implementation support intervention incorporates seven strategies including executive support, in-School Champion, teacher training, resources, prompts, audit and feedback and access to an external Support Officer. The primary trial outcome will be the proportion of schools meeting at least four of the seven physical activity practices of the program, assessed via surveys with Head Physical Education teachers at 12 and 24-months. Secondary outcomes will be assessed via a nested evaluation of student PA and adiposity at 12-months (Grade 8 students) and 24 months (Grade 9 students) undertaken in 30 schools (15 per group). Resource use associated with the implementation intervention will be measured prospectively. Linear mixed effects regression models will assess program effects on the primary outcome at each follow-up period. DISCUSSION: This study is one of few evidence-based multi-component PA programs scaled-up to a large number of secondary schools and evaluated via randomised controlled trial. The use of implementation science theoretical frameworks to implement the evidence-based program and the rigorous evaluation design are strengths of the study. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12617000681358 registered 12th May 2017. Protocol Version 1.

Optimisation: defining and exploring a concept to enhance the impact of public health initiatives.

BACKGROUND: Repeated, data-driven optimisation processes have been applied in many fields to rapidly transform the performance of products, processes and interventions. While such processes may similarly be employed to enhance the impact of public health initiatives, optimisation has not been defined in the context of public health and there has been little exploration of its key concepts. METHODS: We used a modified, three-round Delphi study with an international group of researchers, public health policy-makers and practitioners to (1) generate a consensus-based definition of optimisation in the context of public health and (2i) describe key considerations for optimisation in that context. A pre-workshop literature review and elicitation of participant views regarding optimisation in public health (round 1) were followed by a daylong workshop and facilitated face-to-face group discussions to refine the definition and generate key considerations (round 2); finally, post-workshop discussions were undertaken to refine and finalise the findings (round 3). A thematic analysis was performed at each round. Study findings reflect an iterative consultation process with study participants. RESULTS: Thirty of 33 invited individuals (91%) participated in the study. Participants reached consensus on the following definition of optimisation in public health: "A deliberate, iterative and data-driven process to improve a health intervention and/or its implementation to meet stakeholder-defined public health impacts within resource constraints". A range of optimisation considerations were explored. Optimisation was considered most suitable when existing public health initiatives are not sufficiently effective, meaningful improvements from an optimisation process are anticipated, quality data to assess impacts are routinely available, and there are stable and ongoing resources to support it. Participants believed optimisation could be applied to improve the impacts of an intervention, an implementation strategy or both, on outcomes valued by stakeholders or end users. While optimisation processes were thought to be facilitated by an understanding of the mechanisms of an intervention or implementation strategy, no agreement was reached regarding the best approach to inform decisions about modifications to improve impact. CONCLUSIONS: The study findings provide a strong basis for future research to explore the potential impact of optimisation in the field of public health.

Multi-isotope imaging mass spectrometry quantifies stem cell division and metabolism.

Mass spectrometry with stable isotope labels has been seminal in discovering the dynamic state of living matter, but is limited to bulk tissues or cells. We developed multi-isotope imaging mass spectrometry (MIMS) that allowed us to view and measure stable isotope incorporation with submicrometre resolution. Here we apply MIMS to diverse organisms, including Drosophila, mice and humans. We test the 'immortal strand hypothesis', which predicts that during asymmetric stem cell division chromosomes containing older template DNA are segregated to the daughter destined to remain a stem cell, thus insuring lifetime genetic stability. After labelling mice with (15)N-thymidine from gestation until post-natal week 8, we find no (15)N label retention by dividing small intestinal crypt cells after a four-week chase. In adult mice administered (15)N-thymidine pulse-chase, we find that proliferating crypt cells dilute the (15)N label, consistent with random strand segregation. We demonstrate the broad utility of MIMS with proof-of-principle studies of lipid turnover in Drosophila and translation to the human haematopoietic system. These studies show that MIMS provides high-resolution quantification of stable isotope labels that cannot be obtained using other techniques and that is broadly applicable to biological and medical research.

Stable isotope analysis of dynamic lipidomics.

Metabolic pathway flux is a fundamental element of biological activity, which can be quantified using a variety of mass spectrometric techniques to monitor incorporation of stable isotope-labelled substrates into metabolic products. This article contrasts developments in electrospray ionisation mass spectrometry (ESI-MS) for the measurement of lipid metabolism with more established gas chromatography mass spectrometry and isotope ratio mass spectrometry methodologies. ESI-MS combined with diagnostic tandem MS/MS scans permits the sensitive and specific analysis of stable isotope-labelled substrates into intact lipid molecular species without the requirement for lipid hydrolysis and derivatisation. Such dynamic lipidomic methodologies using non-toxic stable isotopes can be readily applied to quantify lipid metabolic fluxes in clinical and metabolic studies in vivo. However, a significant current limitation is the absence of appropriate software to generate kinetic models of substrate incorporation into multiple products in the time domain. Finally, we discuss the future potential of stable isotope-mass spectrometry imaging to quantify the location as well as the extent of lipid synthesis. This article is part of a Special Issue entitled: BBALIP_Lipidomics Opinion Articles edited by Sepp Kohlwein.

Heterologous Production of Fungal Maleidrides Reveals the Cryptic Cyclization Involved in their Biosynthesis.

Fungal maleidrides are an important family of bioactive secondary metabolites that consist of 7, 8, or 9-membered carbocycles with one or two fused maleic anhydride moieties. The biosynthesis of byssochlamic acid (a nonadride) and agnestadride A (a heptadride) was investigated through gene disruption and heterologous expression experiments. The results reveal that the precursors for cyclization are formed by an iterative highly reducing fungal polyketide synthase supported by a hydrolase, together with two citrate-processing enzymes. The enigmatic ring formation is catalyzed by two proteins with homology to ketosteroid isomerases, and assisted by two proteins with homology to phosphatidylethanolamine-binding proteins.