22 research outputs found

    Colony organization in the green alga Botryococcus braunii (Race B) is specified by a complex extracellular matrix

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    Botryococcus braunii is a colonial green alga whose cells associate via a complex extracellular matrix (ECM) and produce prodigious amounts of liquid hydrocarbons that can be readily converted into conventional combustion engine fuels. We used quick-freeze deep-etch electron microscopy and biochemical/histochemical analysis to elucidate many new features of B. braunii cell/colony organization and composition. Intracellular lipid bodies associate with the chloroplast and endoplasmic reticulum (ER) but show no evidence of being secreted. The ER displays striking fenestrations and forms a continuous subcortical system in direct contact with the cell membrane. The ECM has three distinct components. (i) Each cell is surrounded by a fibrous β-1, 4- and/or β-1, 3-glucan-containing cell wall. (ii) The intracolonial ECM space is filled with a cross-linked hydrocarbon network permeated with liquid hydrocarbons. (iii) Colonies are enclosed in a retaining wall festooned with a fibrillar sheath dominated by arabinose-galactose polysaccharides, which sequesters ECM liquid hydrocarbons. Each cell apex associates with the retaining wall and contributes to its synthesis. Retaining-wall domains also form “drapes” between cells, with some folding in on themselves and penetrating the hydrocarbon interior of a mother colony, partitioning it into daughter colonies. We propose that retaining-wall components are synthesized in the apical Golgi apparatus, delivered to apical ER fenestrations, and assembled on the surfaces of apical cell walls, where a proteinaceous granular layer apparently participates in fibril morphogenesis. We further propose that hydrocarbons are produced by the nonapical ER, directly delivered to the contiguous cell membrane, and pass across the nonapical cell wall into the hydrocarbon-based ECM

    The path to triacylglyceride obesity in the sta6 strain of Chlamydomonas reinhardtii

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    When the sta6 (starch-null) strain of the green microalga Chlamydomonas reinhardtii is nitrogen starved in acetate and then “boosted” after 2 days with additional acetate, the cells become “obese” after 8 days, with triacylglyceride (TAG)-filled lipid bodies filling their cytoplasm and chloroplasts. To assess the transcriptional correlates of this response, the sta6 strain and the starch-forming cw15 strain were subjected to RNA-Seq analysis during the 2 days prior and 2 days after the boost, and the data were compared with published reports using other strains and growth conditions. During the 2 h after the boost, ∼425 genes are upregulated ≥2-fold and ∼875 genes are downregulated ≥2-fold in each strain. Expression of a small subset of “sensitive” genes, encoding enzymes involved in the glyoxylate and Calvin-Benson cycles, gluconeogenesis, and the pentose phosphate pathway, is responsive to culture conditions and genetic background as well as to boosting. Four genes—encoding a diacylglycerol acyltransferase (DGTT2), a glycerol-3-P dehydrogenase (GPD3), and two candidate lipases (Cre03.g155250 and Cre17.g735600)—are selectively upregulated in the sta6 strain. Although the bulk rate of acetate depletion from the medium is not boost enhanced, three candidate acetate permease-encoding genes in the GPR1/FUN34/YaaH superfamily are boost upregulated, and 13 of the “sensitive” genes are strongly responsive to the cell's acetate status. A cohort of 64 autophagy-related genes is downregulated by the boost. Our results indicate that the boost serves both to avert an autophagy program and to prolong the operation of key pathways that shuttle carbon from acetate into storage lipid, the combined outcome being enhanced TAG accumulation, notably in the sta6 strain

    Implementation of the StandingTall programme to prevent falls in older people:a process evaluation protocol

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    INTRODUCTION: One in three people aged 65 years and over fall each year. The health, economic and personal impact of falls will grow substantially in the coming years due to population ageing. Developing and implementing cost-effective strategies to prevent falls and mobility problems among older people is therefore an urgent public health challenge. StandingTall is a low-cost, unsupervised, home-based balance exercise programme delivered through a computer or tablet. StandingTall has a simple user-interface that incorporates physical and behavioural elements designed to promote compliance. A large randomised controlled trial in 503 community-dwelling older people has shown that StandingTall is safe, has high adherence rates and is effective in improving balance and reducing falls. The current project targets a major need for older people and will address the final steps needed to scale this innovative technology for widespread use by older people across Australia and internationally. METHODS AND ANALYSIS: This project will endeavour to recruit 300 participants across three sites in Australia and 100 participants in the UK. The aim of the study is to evaluate the implementation of StandingTall into the community and health service settings in Australia and the UK. The nested process evaluation will use both quantitative and qualitative methods to explore uptake and acceptability of the StandingTall programme and associated resources. The primary outcome is participant adherence to the StandingTall programme over 6 months. ETHICS AND DISSEMINATION: Ethical approval has been obtained from the South East Sydney Local Health District Human Research Ethics Committee (HREC reference 18/288) in Australia and the North West- Greater Manchester South Research Ethics Committee (IRAS ID: 268954) in the UK. Dissemination will be via publications, conferences, newsletter articles, social media, talks to clinicians and consumers and meetings with health departments/managers. TRIAL REGISTRATION NUMBER: ACTRN12619001329156

    Implementation of a digital exercise programme in health services to prevent falls in older people.

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    Background: StandingTall uses eHealth to deliver evidence-based balance and functional strength exercises. Clinical trials have demonstrated improved balance, reduced falls and fall-related injuries and high adherence. This study aimed to evaluate the implementation of StandingTall into health services in Australia and the UK.Methods:Two hundred and forty-six participants (Australia, n = 184; UK, n = 62) were recruited and encouraged to use StandingTall for 2 h/week for 6-months. A mixed-methods process evaluation assessed uptake and acceptability of StandingTall. Adherence, measured as % of prescribed dose completed, was the primary outcome.Results: The study, conducted October 2019 to September 2021 in Australia and November 2020 to April 2022 in the UK, was affected by COVID-19. Participants’ mean age was 73 ± 7 years, and 196 (81%) were female. Of 129 implementation partners (e.g. private practice clinicians, community exercise providers, community service agencies) approached, 34% (n = 44) agreed to be implementation partners. Of 41 implementation partners who referred participants, 15 (37%) referred ≥5. Participant uptake was 42% (198/469) with mean adherence over 6 months being 41 ± 39% of the prescribed dose (i.e. 39 ± 41 min/week) of exercise. At 6 months, 120 (76%) participants indicated they liked using StandingTall, 89 (56%) reported their balance improved (moderately to a great deal better) and 125 (80%) rated StandingTall as good to excellent. For ongoing sustainability, health service managers highlighted the need for additional resources.Conclusions: StandingTall faced challenges in uptake, adoption and sustainability due to COVID-19 and a lack of ongoing funding. Adherence levels were lower than the effectiveness trial, but were higher than other exercise studies. Acceptance was high, indicating promise for future implementation, provided sufficient resources and support are made available

    Mental health problems due to community violence exposure in a small urban setting

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    Objective: Studies conducted in large metropolitan inner-city communities with high violent crime rates have demonstrated an association between exposure to violence and mental health problems; therefore the purpose of this study was to determine if similar trends exist in smaller inner-city communities with substantially lower violent crime rates. Methods: One hundred twenty-six children and young adults living in inner-city Omaha, Nebraska, were screened for posttraumatic stress disorder (PTSD), depression, and anxiety symptoms and assessed for community violence exposure (CVE). Pearson’s correlation and analysis of variance were used to determine the relationship between PTSD, depression, and anxiety symptoms and CVE. Results: A statistically significant relationship was found between CVE and PTSD and anxiety symptoms among participants despite their having lower rates of exposure to violent events in comparison with other studies. No association was found between violence and depression symptoms. Additionally, the presence of anxiety and depression, as well as increased age of participants, was associated with higher rates of PTSD symptoms. Conclusion: We recommend that health care providers in smaller cities, where the effects of violent crime may be underestimated or overlooked, be informed of the existence of this public health problem within their community and that they screen at-risk patients for mental health problems

    Immunoregulatory Sertoli Cell Allografts Engineered to Express Human Insulin Survive Humoral-Mediated Rejection

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    An effective treatment and possible cure for type 1 diabetes is transplantation of pancreatic islets. Unfortunately, transplanted islets are rejected by the immune system with humoral-mediated responses being an important part of rejection. Sertoli cells (SC), an immune regulatory cell shown to survive as allografts long-term without immunosuppressants, have the potential to be used as a cell-based gene therapy vehicle to deliver endogenous insulin—a possible alternative to islets. Previously, we transduced a mouse SC line to produce human insulin. After transplantation into diabetic mice, these cells consistently produced low levels of insulin with graft survival of 75% at 50 days post-transplantation. The object of this study was to assess humoral immune regulation by these engineered SC. Both nontransduced and transduced SC survived exposure to human serum with complement in vitro. Analysis of allografts in vivo at 20 and 50 days post-transplantation revealed that despite IgG antibody detection, complement factor deposition was low and grafts survived through 50 days post-transplantation. Furthermore, the transduced SC secreted elevated levels of the complement inhibitor C1q binding protein. Overall, this suggests SC genetically engineered to express insulin maintain their ability to prevent complement-mediated killing. Since inhibiting complement-mediated rejection is important for graft survival, further studies of how SC modifies the immune response could be utilized to advance the use of genetically engineered SC or to prolong islet allograft survival to improve the treatment of diabetes

    R script for analysis of diet and immunity from Isle of May mice

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    This script accompanies the data file "IoM_mousedata_dietandimmunity.csv" and carries out the analysis and plots described in the paper Taylor et al. 2019 "Immune state is associated with natural dietary variation in wild mice Mus musculus domesticus" Functional Ecology

    Data from: Immune state is associated with natural dietary variation in wild mice Mus musculus domesticus

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    1.The ability, propensity and need to mount an immune response vary both among individuals and within a single individual over time. 2.A wide array of parameters have been found to influence immune state in carefully controlled experiments, but we understand much less about which of these parameters are important in determining immune state in wild populations. 3.Diet can influence immune responses, for example when nutrient availability is limited. We therefore predict that natural dietary variation will play a role in modulating immune state, but this has never been tested. 4.We measured carbon and nitrogen stable isotope ratios in an island population of house mice Mus musculus domesticus as an indication of dietary variation, and the expression of a range of immune‐related genes to represent immune state. 5.After accounting for potential confounding influences such as age, sex and helminth load, we found a significant association between carbon isotope ratio and levels of immune activity in the mesenteric lymph nodes, particularly in relation to the inflammatory response. 6.This association demonstrates the important interplay between diet and an animal's response to immune challenges, and therefore potentially its susceptibility to disease

    Ginger Root Extract Improves GI Health in Diabetic Rats by Improving Intestinal Integrity and Mitochondrial Function

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    Background Emerging research suggests hyperglycemia can increase intestinal permeability. Ginger and its bioactive compounds have been reported to benefit diabetic animals due to their anti-inflammatory and antioxidant properties. In this study, we revealed the beneficial effect of gingerol-enriched ginger (GEG) on intestinal health (i.e., barrier function, mitochondrial function, and anti-inflammation) in diabetic rats. Methods Thirty-three male Sprague Dawley rats were assigned to three groups: low-fat diet (control group), high-fat-diet (HFD) + streptozotocin (single low dose 35 mg/kg body weight (BW) after 2 weeks of HFD feeding) (DM group), and HFD + streptozotocin + 0.75% GEG in diet (GEG group) for 42 days. Glucose tolerance tests (GTT) and insulin tolerance tests (ITT) were conducted at baseline and prior to sample collection. Total pancreatic insulin content was determined by ELISA. Total RNA of intestinal tissues was extracted for mRNA expression using qRT-PCR. Results Compared to the DM group, the GEG group had improved glucose tolerance and increased pancreatic insulin content. Compared to those without GEG (DM group), GEG supplementation (GEG group) increased the gene expression of tight junction (Claudin-3) and antioxidant capacity (SOD1), while it decreased the gene expression for mitochondrial fusion (MFN1), fission (FIS1), biogenesis (PGC-1α, TFAM), mitophagy (LC3B, P62, PINK1), and inflammation (NF-κB). Conclusions Ginger root extract improved glucose homeostasis in diabetic rats, in part, via improving intestinal integrity and mitochondrial dysfunction of GI health
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