Exploring the Interrelationships Between Physical Function, Functional Exercise Capacity, and Exercise Self-Efficacy in Persons Living with HIV.

PURPOSE: To determine if there were differences between the subjective and objective assessments of physical activity while controlling for sociodemographic, anthropometric, and clinical characteristics. SETTING/SAMPLE: A total of 810 participants across eight sites located in three countries. MEASURES: Subjective instruments were the two subscales of Self-efficacy for Exercise Behaviors Scale: Making Time for Exercise and Resisting Relapse and Patient-Reported Outcomes Measurement Information System, which measured physical function. The objective measure of functional exercise capacity was the 6-minute Walk Test. ANALYSIS: Both univariate and multivariant analyses were used. RESULTS: Physical function was significantly associated with Making Time for Exercise (ß = 1.76, p = .039) but not with Resisting Relapse (ß = 1.16, p = .168). Age (ß = -1.88, p = .001), being employed (ß = 16.19, p < .001) and race (ßs = 13.84-31.98, p < .001), hip-waist ratio (ß = -2.18, p < .001), and comorbidities (ß = 7.31, p < .001) were significant predictors of physical functioning. The model predicting physical function accounted for a large amount of variance (adjusted R2 = .938). The patterns of results predicting functional exercise capacity were similar. Making Time for Exercise self-efficacy scores significantly predicted functional exercise capacity (ß = 0.14, p = .029), and Resisting Relapse scores again did not (ß = -0.10, p = .120). Among the covariates, age (ß = -0.16, p < .001), gender (ß = -0.43, p < .001), education (ß = 0.08, p = .026), and hip-waist ratio (ß = 0.09, p = .034) were significant. This model did not account for much of the overall variance in the data (adjusted R2 = .081). We found a modest significant relationship between physical function and functional exercise capacity (r = 0.27). CONCLUSIONS: Making Time for Exercise Self-efficacy was more significant than Resisting Relapse for both physical function and functional exercise capacity. Interventions to promote achievement of physical activity need to use multiple measurement strategies.

Working status and seasonal meteorological conditions predict physical activity levels in people living with HIV.

Little is known about how demographic, employment and meteorological factors impact physical activity. We conducted an analysis to explore these associations from participants (N = 447) from six cities in the United States and matched their activity data with abstracted local meteorological data from National Oceanic and Atmospheric Administration (NOAA) weather reports. Participants were purposively recruited in 3-month blocks, from December 2015 to October 2017, to reflect physical activity engagement across the seasons. We calculated total physical activity (minutes/week) based on 7-day physical activity recall. Mild correlations were observed between meteorological factors and correlated with lower physical activity. Participants were least active in autumn (Median = 220 min/week) and most active in spring (Median = 375 min/week). In addition to level of education and total hours of work, maximum temperature, relative humidity, heating degree day, precipitation and sunset time together explained 17.6% of variance in total physical activity. Programs assisting in employment for PLHIV and those that promote indoor physical activity during more strenuous seasons are needed. Additional research to better understand the selection, preferences, and impact of indoor environments on physical activity is warranted.

Maintaining cancer services during the COVID-19 pandemic: the Aotearoa New Zealand experience.

COVID-19 caused significant disruption to cancer services around the world. The health system in Aotearoa New Zealand has fared better than many other regions, with the country being successful, so far, in avoiding sustained community transmission. However, there was a significant initial disruption to services across the cancer continuum, resulting in a decrease in the number of new diagnoses of cancer in March and April 2020. Te Aho o Te Kahu, Aotearoa New Zealand's national Cancer Control Agency, coordinated a nationwide response to minimise the impact of COVID-19 on people with cancer. The response, outlined in this paper, included rapid clinical governance, a strong equity focus, development of national clinical guidance, utilising new ways of delivering care, identifying and addressing systems issues and close monitoring and reporting of the impact on cancer services. Diagnostic procedures and new cancer registrations increased in the months following the national lockdown, and the cumulative number of cancer registrations in 2020 surpassed the number of registrations in 2019 by the end of September. Cancer treatment services - surgery, medical oncology, radiation oncology and haematology - continued during the national COVID-19 lockdown in March and April 2020 and continued to be delivered at pre-COVID-19 volumes in the months since. We are cautiously optimistic that, in general, the COVID-19 pandemic does not appear to have increased inequities in cancer diagnosis and treatment for Maori in Aotearoa New Zealand.

Social media use as a predictor of higher body mass index in persons living with HIV.

Social media tools have been touted as an approach to bring more democratic communication to health care. We conducted a multi-site cross-sectional study among persons living with HIV (PLWH) to desrcibe technology use among PLWH in the US and the association between social media use and body-mass index (BMI). Our primary predictor variable was social media use. Our primary outcome was BMI measured through height and weight. Descriptive statistics were used to describe the demographic profiles of the study participants and linear regression models were used to analyze associations between the outcome and predictor variables controlling for demographic characteristics. Study participants (N = 606) across 6 study sites in the United States were predominately 50-74 years old (67%). Thirty-three percent of study participants had a normal weight (BMI 18.5-25), 33% were overweight (BMI 25-30), and 32% were obese (BMI > 30). Participants used several social media sites with Facebook (45.6%) predominating. Social media use was associated with higher BMI in study participants (p < .001) and this effect persisted, although not as strongly, when limiting the analysis to those who only those who used Facebook (p = .03). Further consideration of social factors that can be ameliorated to improve health outcomes is timely and needed.

Overexpression of an endogenous type 2 diacylglycerol acyltransferase in the marine diatom Phaeodactylum tricornutum enhances lipid production and omega-3 long-chain polyunsaturated fatty acid content.

BACKGROUND: Oleaginous microalgae represent a valuable resource for the production of high-value molecules. Considering the importance of omega-3 long-chain polyunsaturated fatty acids (LC-PUFAs) for human health and nutrition the yields of high-value eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) require significant improvement to meet demand; however, the current cost of production remains high. A promising approach is to metabolically engineer strains with enhanced levels of triacylglycerols (TAGs) enriched in EPA and DHA. RESULTS: Recently, we have engineered the marine diatom Phaeodactylum tricornutum to accumulate enhanced levels of DHA in TAG. To further improve the incorporation of omega-3 LC-PUFAs in TAG, we focused our effort on the identification of a type 2 acyl-CoA:diacylglycerol acyltransferase (DGAT) capable of improving lipid production and the incorporation of DHA in TAG. DGAT is a key enzyme in lipid synthesis. Following a diatom based in vivo screen of candidate DGATs, a native P. tricornutum DGAT2B was taken forward for detailed characterisation. Overexpression of the endogenous P. tricornutum DGAT2B was confirmed by qRT-PCR and the transgenic strain grew successfully in comparison to wildtype. PtDGAT2B has broad substrate specificity with preferences for C16 and LC-PUFAs acyl groups. Moreover, the overexpression of an endogenous DGAT2B resulted in higher lipid yields and enhanced levels of DHA in TAG. Furthermore, a combined overexpression of the endogenous DGAT2B and ectopic expression of a Δ5-elongase showed how iterative metabolic engineering can be used to increase DHA and TAG content, irrespective of nitrogen treatment. CONCLUSION: This study provides further insight into lipid metabolism in P. tricornutum and suggests a metabolic engineering approach for the efficient production of EPA and DHA in microalgae.

The Relationship Between Physical Activity and Cardiorespiratory Fitness Among People Living With Human Immunodeficiency Virus Throughout the Life Span.

BACKGROUND: People living with human immunodeficiency virus (PLHIV) are at an increased risk for developing cardiovascular disease (CVD). Physical activity and cardiorespiratory fitness in PLHIV are poorly understood. OBJECTIVE: The aims of this study were to describe physical activity and cardiorespiratory fitness by sex and age and to examine the association between physical activity and cardiorespiratory fitness in PLHIV, controlling for covariates. METHODS: Seven hundred two PLHIV participated in a cross-sectional study and completed validated measures of self-reported physical activity (7-day Physical Activity Recall) and cardiorespiratory fitness (6-minute walk test). Participants were recruited from 7 diverse sites in the United States and Thailand, and data were analyzed using descriptive statistics and multiple regression to examine the relationship between physical activity and cardiorespiratory fitness. RESULTS: On average, participants self-reported engaging in 115 minutes of, mostly light (75%), physical activity. Men reported twice the amount of physical activity as women (155 vs 73 minutes, P = .01). Participants' ability to achieve their predicted 6-minute walk test distances was similar between men (68%) and women (69%) (P > .01). For women, vigorous physical activity was associated with a 6.6% increase in cardiorespiratory fitness and being temporarily unemployed was associated with an 18% decline in cardiorespiratory fitness. Cardiorespiratory fitness increased with age (P < .01). CONCLUSIONS: Weekly physical activity of people living with human immunodeficiency virus averaged 85 minutes of mostly light activity, well below the recommended 150 minutes of moderate activity. Vigorous physical activity was associated with improved cardiorespiratory fitness in women, but not men. Although PLHIV would benefit from interventions to increase physical activity, our data suggest a need to develop sex-specific physical activity strategies.

90-90-90-Plus: Maintaining Adherence to Antiretroviral Therapies.

Medication adherence is the "Plus" in the global challenge to have 90% of HIV-infected individuals tested, 90% of those who are HIV positive treated, and 90% of those treated achieve an undetectable viral load. The latter indicates viral suppression, the goal for clinicians treating people living with HIV (PLWH). The comparative importance of different psychosocial scales in predicting the level of antiretroviral adherence, however, has been little studied. Using data from a cross-sectional study of medication adherence with an international convenience sample of 1811 PLWH, we categorized respondent medication adherence as None (0%), Low (1-60%), Moderate (61-94%), and High (95-100%) adherence based on self-report. The survey contained 13 psychosocial scales/indices, all of which were correlated with one another (p < 0.05 or less) and had differing degrees of association with the levels of adherence. Controlling for the influence of race, gender, education, and ability to pay for care, all scales/indices were associated with adherence, with the exception of Berger's perceived stigma scale. Using forward selection stepwise regression, we found that adherence self-efficacy, depression, stressful life events, and perceived stigma were significant predictors of medication adherence. Among the demographic variables entered into the model, nonwhite race was associated with double the odds of being in the None rather than in the High adherence category, suggesting these individuals may require additional support. In addition, asking about self-efficacy, depression, stigma, and stressful life events also will be beneficial in identifying patients requiring greater adherence support. This support is essential to medication adherence, the Plus to 90-90-90.

Metabolome Analysis Reveals Betaine Lipids as Major Source for Triglyceride Formation, and the Accumulation of Sedoheptulose during Nitrogen-Starvation of Phaeodactylum tricornutum.

Oleaginous microalgae are considered as a promising resource for the production of biofuels. Especially diatoms arouse interest as biofuel producers since they are most productive in carbon fixation and very flexible to environmental changes in the nature. Naturally, triacylglycerol (TAG) accumulation in algae only occurs under stress conditions like nitrogen-limitation. We focused on Phaeodactylum strain Pt4 (UTEX 646), because of its ability to grow in medium with low salinity and therefore being suited when saline water is less available or for wastewater cultivation strategies. Our data show an increase in neutral lipids during nitrogen-depletion and predominantly 16:0 and 16:1(n-7) accumulated in the TAG fraction. The molecular species composition of TAG suggests a remodeling primarily from the betaine lipid diacylglyceroltrimethylhomoserine (DGTS), but a contribution of the chloroplast galactolipid monogalactosyldiacylglycerol (MGDG) cannot be excluded. Interestingly, the acyl-CoA pool is rich in 20:5(n-3) and 22:6(n-3) in all analyzed conditions, but these fatty acids are almost excluded from TAG. Other metabolites most obviously depleted under nitrogen-starvation were amino acids, lyso-phospholipids and tricarboxylic acid (TCA) cycle intermediates, whereas sulfur-containing metabolites as dimethylsulfoniopropionate, dimethylsulfoniobutyrate and methylsulfate as well as short acyl chain carnitines, propanoyl-carnitine and butanoyl-carnitine increased upon nitrogen-starvation. Moreover, the Calvin cycle may be de-regulated since sedoheptulose accumulated after nitrogen-depletion. Together the data provide now the basis for new strategies to improve lipid production and storage in Phaeodactylum strain Pt4.

Improving resolution in quantum subnanometre-gap tip-enhanced Raman nanoimaging.

Two-dimensional (2D) materials beyond graphene such as transition metal dichalcogenides (TMDs) have unique mechanical, optical and electronic properties with promising applications in flexible devices, catalysis and sensing. Optical imaging of TMDs using photoluminescence and Raman spectroscopy can reveal the effects of structure, strain, doping, edge states, and surface functionalization from materials to bioscience. However, Raman signals are inherently weak and so far have been limited in spatial resolution in TMDs to a few hundred nanometres which is much larger than the intrinsic scale of these effects. Here we overcome the diffraction limit by using resonant tip-enhanced Raman scattering (TERS) of few-layer MoS2, and obtain nanoscale optical images with ~20 nm spatial resolution. This becomes possible due to electric field enhancement in an optimized subnanometre-gap resonant tip-substrate configuration. We investigate the limits of signal enhancement by varying the tip-sample gap with sub-Angstrom precision and observe a quantum quenching behavior, as well as a Schottky-Ohmic transition, for subnanometre gaps, which enable surface mapping based on this new contrast mechanism. This quantum regime of plasmonic gap-mode enhancement with a few nanometre thick MoS2 junction may be used for designing new quantum optoelectronic devices and sensors with a wide range of applications.

Heterotrophic Production of Omega-3 Long-Chain Polyunsaturated Fatty Acids by Trophically Converted Marine Diatom Phaeodactylum tricornutum.

We have created via metabolic engineering a heterotrophic strain of Phaeodactylum tricornutum that accumulates enhanced levels of the high value omega-3 long chain polyunsaturated fatty acid (LC-PUFAs) docosahexaenoic acid (DHA). This was achieved by generation of transgenic strains in which the Δ5-elongase from Ostreococcus tauri was co-expressed with a glucose transporter from the moss Physcomitrella patens. This double transformant has the capacity to grow in the dark in liquid medium supplemented with glucose and accumulate substantial levels of omega-3 LC-PUFAs. The effects of glucose concentrations on growth and LC-PUFA production of wild type and transformed strains cultivated in the light and dark were studied. The highest omega-3 LC-PUFAs accumulation was observed in cultures grown under mixotrophic conditions in the presence of 1% glucose (up to 32.2% of total fatty acids, TFA). Both DHA and EPA are detected at high levels in the neutral lipids of transgenic cells grown under phototrophic conditions, averaging 36.5% and 23.6% of TFA, respectively. This study demonstrates the potential for P. tricornutum to be developed as a viable commercial strain for both EPA and DHA production under mixo- and heterotrophic conditions.

Towards the Industrial Production of Omega-3 Long Chain Polyunsaturated Fatty Acids from a Genetically Modified Diatom Phaeodactylum tricornutum.

The marine diatom Phaeodactylum tricornutum can accumulate up to 30% of the omega-3 long chain polyunsaturated fatty acid (LC-PUFA) eicosapentaenoic acid (EPA) and, as such, is considered a good source for the industrial production of EPA. However, P. tricornutum does not naturally accumulate significant levels of the more valuable omega-3 LC-PUFA docosahexaenoic acid (DHA). Previously, we have engineered P. tricornutum to accumulate elevated levels of DHA and docosapentaenoic acid (DPA) by overexpressing heterologous genes encoding enzyme activities of the LC-PUFA biosynthetic pathway. Here, the transgenic strain Pt_Elo5 has been investigated for the scalable production of EPA and DHA. Studies have been performed at the laboratory scale on the cultures growing in up to 1 L flasks a 3.5 L bubble column, a 550 L closed photobioreactor and a 1250 L raceway pond with artificial illumination. Detailed studies were carried out on the effect of different media, carbon sources and illumination on omega-3 LC-PUFAs production by transgenic strain Pt_Elo5 and wild type P. tricornutum grown in 3.5 L bubble columns. The highest content of DHA (7.5% of total fatty acids, TFA) in transgenic strain was achieved in cultures grown in seawater salts, Instant Ocean (IO), supplemented with F/2 nutrients (F2N) under continuous light. After identifying the optimal conditions for omega-3 LC-PUFA accumulation in the small-scale experiments we compared EPA and DHA levels of the transgenic strain grown in a larger fence-style tubular photobioreactor and a raceway pond. We observed a significant production of DHA over EPA, generating an EPA/DPA/DHA profile of 8.7%/4.5%/12.3% of TFA in cells grown in a photobioreactor, equivalent to 6.4 µg/mg dry weight DHA in a mid-exponentially growing algal culture. Omega-3 LC-PUFAs production in a raceway pond at ambient temperature but supplemented with artificial illumination (110 µmol photons m-2s-1) on a 16:8h light:dark cycle, in natural seawater and F/2 nutrients was 24.8% EPA and 10.3% DHA. Transgenic strain grown in RP produced the highest levels of EPA (12.8%) incorporated in neutral lipids. However, the highest partitioning of DHA in neutral lipids was observed in cultures grown in PBR (7.1%). Our results clearly demonstrate the potential for the development of the transgenic Pt_Elo5 as a platform for the commercial production of EPA and DHA.

The biosynthesis of allelopathic di-C-glycosylflavones from the roots of Desmodium incanum (G. Mey.) DC.

The allelopathic root exudate of the drought-tolerant subsistence cereal intercrop D. incanum, protecting against the parasitic weed Striga hermonthica, comprises a number of di-C-glycosylflavones specifically containing C-glucosyl, C-galactosyl and C-arabinosyl moieties. Here we demonstrate that the biosynthesis of all compounds containing a C-glucose involves C-glucosylation of 2-hydroxynaringenin with subsequent C-galactosylation, C-glucosylation or C-arabinosylation. In addition, the crude soluble enzyme extract converts two fluorinated 2-hydroxyflavanone analogues to corresponding mono- and di-C-glycosylflavones demonstrating that some differences in C-ring substitution can be tolerated by the plant enzymes. Elucidating the biosynthesis of these C-glycosylflavones (CGFs) has the potential to open up opportunities for transferring the enzymic and genetic basis for the S. hermonthica inhibiting allelopathic trait to food crop plants.

Effects of copper and cadmium on development and superoxide dismutase levels in horseshoe crab (Limulus polyphemus) embryos.

Pollution by metals may adversely affect organisms through the generation of reactive oxygen species (ROS). In this study, we examined the sublethal effects of two metals, copper and cadmium, on horseshoe crab (Limulus polyphemus) embryos. Exposure to copper or cadmium at concentrations of 0.01-10 mg/L for periods of 4, 8, 16 and 24 h had minimal effect on embryo survival except at 100 mg/L Cu. However, metal-exposed embryos took significantly longer to hatch into first instar ("trilobite") larvae than seawater controls. Levels of superoxide dismutase (SOD), believed to be important in the response to oxidative stress, were determined by Western blotting. Both the Cu/Zn and Mn cofactor forms of SOD tended to be somewhat elevated in metal-exposed embryos, but the increases were neither dose nor time-dependent. Likewise, SOD enzymatic activity showed no significant differences comparing embryos exposed to metals with seawater controls. We conclude that the protective role of SOD's against ROS produced in response to metal exposure appears to be limited in horseshoe crab embryos, at least under our experimental conditions.

Opportunities, hurdles, solutions, and approaches to transition military veterans into professional nursing programs.

Capitalizing on the almost 2.2 million service members returning from Operation Iraqi Freedom and New Dawn (OIF) in Iraq, and Operation Enduring Freedom (OEF) in Afghanistan, baccalaureate educators are encouraged to create realistic, applicable nursing transitional programs for the health and health-related oriented military veterans. Opportunities, hurdles, and solutions related to the veteran's unique socio-economic circumstances of education, finances, and advisement are provided so the potential veteran student is successful within the university's milieu. Transitional nursing educational interventions related to assessment, didactic, and clinical used by two baccalaureate nursing curriculums, including the eLineMilitary* (ELM) Program, provide approaches of how to propel the veteran's journey toward graduation in a professional nursing program. These interventions include modular didactic, competency based education, as well as the concentrated, collegial time within the Faculty/Clinical Coach triad for essential role modeling, care, and skills.

Engagement with Care, Substance Use, and Adherence to Therapy in HIV/AIDS.

Engagement with care for those living with HIV is aimed at establishing a strong relationship between patients and their health care provider and is often associated with greater adherence to therapy and treatment (Flickinger, Saha, Moore, and Beach, 2013). Substance use behaviors are linked with lower rates of engagement with care and medication adherence (Horvath, Carrico, Simoni, Boyer, Amico, and Petroli, 2013). This study is a secondary data analysis using a cross-sectional design from a larger randomized controlled trial (n = 775) that investigated the efficacy of a self-care symptom management manual for participants living with HIV. Participants were recruited from countries of Africa and the US. This study provides evidence that substance use is linked with lower self-reported engagement with care and adherence to therapy. Data on substance use and engagement are presented. Clinical implications of the study address the importance of utilizing health care system and policy factors to improve engagement with care.

Investigating the photoprotective role of cytochrome b-559 in photosystem II in a mutant with altered ligation of the haem.

Despite many years of study, the physiological role of cytochrome b-559 (Cyt b-559) within the photosystem II (PSII) complex still remains unclear. Here we describe the analysis of a mutant of the green alga Chlamydomonas reinhardtii in which the His ligand to the haem, provided by the alpha subunit, has been replaced by a Cys residue. The mutant is unable to grow photoautotrophically but can assemble oxygen-evolving PSII supercomplexes to 15-20% of the levels found in the wild-type control. Haem is still detected in the isolated PSII supercomplexes but at sub-stoichiometric levels consistent with weaker binding to the mutated cytochrome. Analysis of PSII activity in cells indicates slowed electron transfer in the mutant between plastoquinones QA and QB. We show that PSII activity in the mutant is more sensitive to chronic photoinhibition than the WT control because of two effects: a faster rate of damage and an impaired PSII repair cycle at the level of synthesis and/or incorporation of D1 into PSII. We also demonstrate that Cyt b-559 plays a role during the critical stage of assembling the Mn4CaO5 cluster. Overall we conclude that Cyt b-559 optimises electron transfer on the acceptor side of PSII and plays physiologically important roles in the assembly, repair and maintenance of the complex.

Self-compassion and risk behavior among people living with HIV/AIDS.

Sexual risk behavior and illicit drug use among people living with HIV/AIDS (PLWHA) contribute to poor health and onward transmission of HIV. The aim of this collaborative multi-site nursing research study was to explore the association between self-compassion and risk behaviors in PLWHA. As part of a larger project, nurse researchers in Canada, China, Namibia, Puerto Rico, Thailand and the US enrolled 1211 sexually active PLWHA using convenience sampling. The majority of the sample was male, middle-aged, and from the US. Illicit drug use was strongly associated with sexual risk behavior, but participants with higher self-compassion were less likely to report sexual risk behavior, even in the presence of illicit drug use. Self-compassion may be a novel area for behavioral intervention development for PLWHA.

Impacts of pesticides in a Central California estuary.

Recent and past studies have documented the prevalence of pyrethroid and organophosphate pesticides in urban and agricultural watersheds in California. While toxic concentrations of these pesticides have been found in freshwater systems, there has been little research into their impacts in marine receiving waters. Our study investigated pesticide impacts in the Santa Maria River estuary, which provides critical habitat to numerous aquatic, terrestrial, and avian species on the central California coast. Runoff from irrigated agriculture constitutes a significant portion of Santa Maria River flow during most of the year, and a number of studies have documented pesticide occurrence and biological impacts in this watershed. Our study extended into the Santa Maria watershed coastal zone and measured pesticide concentrations throughout the estuary, including the water column and sediments. Biological effects were measured at the organism and community levels. Results of this study suggest the Santa Maria River estuary is impacted by current-use pesticides. The majority of water samples were highly toxic to invertebrates (Ceriodaphnia dubia and Hyalella azteca), and chemistry evidence suggests toxicity was associated with the organophosphate pesticide chlorpyrifos, pyrethroid pesticides, or mixtures of both classes of pesticides. A high percentage of sediment samples were also toxic in this estuary, and sediment toxicity occurred when mixtures of chlorpyrifos and pyrethroid pesticides exceeded established toxicity thresholds. Based on a Relative Benthic Index, Santa Maria estuary stations where benthic macroinvertebrate communities were assessed were degraded. Impacts in the Santa Maria River estuary were likely due to the proximity of this system to Orcutt Creek, the tributary which accounts for most of the flow to the lower Santa Maria River. Water and sediment samples from Orcutt Creek were highly toxic to invertebrates due to mixtures of the same pesticides measured in the estuary. This study suggests that the same pyrethroid and organophosphate pesticides that have been shown to cause water and sediment toxicity in urban and agriculture water bodies throughout California, have the potential to affect estuarine habitats. The results establish baseline data in the Santa Maria River estuary to allow evaluation of ecosystem improvement as management initiatives to reduce pesticide runoff are implemented in this watershed.

Metabolic engineering of Phaeodactylum tricornutum for the enhanced accumulation of omega-3 long chain polyunsaturated fatty acids.

We have engineered the diatom Phaeodactylum tricornutum to accumulate the high value omega-3 long chain polyunsaturated fatty acid docosahexaenoic acid (DHA). This was achieved by the generation of transgenic strains in which the Δ5-elongase from the picoalga Ostreococcus tauri was expressed to augment the endogenous fatty acid biosynthetic pathway. Expression of the heterologous elongase resulted in an eight-fold increase in docosahexaenoic acid content, representing a marked and valuable change in the fatty acid profile of this microalga. Importantly, DHA was shown to accumulate in triacylglycerols, with several novel triacylglycerol species being detected in the transgenic strains. In a second iteration, co-expression of an acyl-CoA-dependent Δ6-desaturase with the Δ5-elongase further increased DHA levels. Together, this demonstrates for the first time the potential of using iterative metabolic engineering to optimise omega-3 content in algae.