The ancient phosphatidylinositol 3-kinase signaling system is a master regulator of energy and carbon metabolism in algae

Algae undergo a complete metabolic transformation under stress by arresting cell growth, inducing autophagy and hyperaccumulating biofuel precursors such as triacylglycerols and starch. However, the regulatory mechanisms behind this stress-induced transformation are still unclear. Here, we use biochemical, mutational, and “omics” approaches to demonstrate that PI3K signaling mediates the homeostasis of energy molecules and influences carbon metabolism in algae. In Chlamydomonas reinhardtii, the inhibition and knockdown (KD) of algal class III PI3K led to significantly decreased cell growth, altered cell morphology, and higher lipid and starch contents. Lipid profiling of wild-type and PI3K KD lines showed significantly reduced membrane lipid breakdown under nitrogen starvation (-N) in the KD. RNA-seq and network analyses showed that under -N conditions, the KD line carried out lipogenesis rather than lipid hydrolysis by initiating de novo fatty acid biosynthesis, which was supported by tricarboxylic acid cycle down-regulation and via acetyl-CoA synthesis from glycolysis. Remarkably, autophagic responses did not have primacy over inositide signaling in algae, unlike in mammals and vascular plants. The mutant displayed a fundamental shift in intracellular energy flux, analogous to that in tumor cells. The high free fatty acid levels and reduced mitochondrial ATP generation led to decreased cell viability. These results indicate that the PI3K signal transduction pathway is the metabolic gatekeeper restraining biofuel yields, thus maintaining fitness and viability under stress in algae. This study demonstrates the existence of homeostasis between starch and lipid synthesis controlled by lipid signaling in algae and expands our understanding of such processes, with biotechnological and evolutionary implications.Ministry of Science, ICT and Future Planning 2015M3A6A2065697Ministry of Oceans and Fisheries 2015018

Challenges and Lessons Learned in the Development of a Participatory Learning and Action Intervention to Tackle Antibiotic Resistance: Experiences From Northern Vietnam

Antibiotic use in the community for humans and animals is high in Vietnam, driven by easy access to over-the counter medicines and poor understanding of the role of antibiotics. This has contributed to antibiotic resistance levels that are amongst the highest in the world. To address this problem, we developed a participatory learning and action (PLA) intervention. Here we describe challenges and lessons learned while developing and testing this intervention in preparation for a large-scale One Health trial in northern Vietnam. We tested the PLA approach using community-led photography, and then reflected on how this approach worked in practice. We reviewed and discussed implementation documentation and developed and refined themes. Five main themes were identified related to challenges and lessons learned: understanding the local context, stakeholder relationship development, participant recruitment, building trust and motivation, and engagement with the topic of antibiotics and antimicrobial resistance (AMR). Partnerships with national and local authorities provided an important foundation for building relationships with communities, and enhanced visibility and credibility of activities. Partnership development required managing relationships, clarifying roles, and accommodating different management styles. When recruiting participants, we had to balance preferences for top-down and bottom-up approaches. Building trust and motivation took time and was challenged by limited study team presence in the community. Open discussions around expectations and appropriate incentives were re-visited throughout the process. Financial incentives provided initial motivation to participate, while less tangible benefits like collective knowledge, social connections, desire to help the community, and new skills, sustained longer-term motivation. Lack of awareness and perceived importance of the problem of AMR, affected initial motivation. Developing mutual understanding through use of common and simplified language helped when discussing the complexities of this topic. A sense of ownership emerged as the study progressed and participants understood more about AMR, how it related to their own concerns, and incorporated their own ideas into activities. PLA can be a powerful way of stimulating community action and bringing people together to tackle a common problem. Understanding the nuances of local power structures, and allowing time for stakeholder relationship development and consensus-building are important considerations when designing engagement projects

The nature and conditions of pragmatic and discourse transfer in cross-cultural interaction investigated through naturalized role-play

© 2004 Dr. Giao Quynh TranFor decades, the first linguistic and cultural influence on second language performance (technically known as pragmatic and discourse transfer) in cross-cultural interaction has fascinated researchers because its nature and especially its conditions have never been fathomed out. The aims of this investigation are threefold. First, it examines the nature of pragmatic and discourse transfer in compliment responses by Vietnamese speakers of English as a second language in cross-cultural interaction with Australians. The examination also takes into account data from conversations among Australian English native speakers and interaction between Vietnamese counterparts. Second, the research project investigates the underexplored conditions of pragmatic and discourse transfer. In the quest for the nature and conditions of pragmatic and discourse transfer, research methodologies provoke much debate because they have different advantages and disadvantages, though the ultimate goal remains the controlled elicitation of data that is comparable to real-life production. The third aim of the present study is to propose and validate an innovative methodology of data collection in cross-cultural and interlanguage pragmatics research the Naturalized Role-play. This methodology is capable of realizing the highly desirable but virtually impossible goal of eliciting spontaneous data in controlled settings. In reference to the methodological design of the research project, the Naturalized Role-play provided the main corpus of data on pragmatic and discourse transfer whose in-depth analysis revealed the nature of this phenomenon. In addition to Naturalized Role-play data, background questionnaire and retrospective interview data was collected to explore conditions of pragmatic and discourse transfer. To demonstrate the effectiveness and validity of the Naturalized Role-play, compliment response data collected by means of the Naturalized Role-play was compared with data from other major methods including the questionnaire, closed role-play, open role-play and natural data recording. Findings of this investigation indicated what was transferred and how pragmatic and discourse transfer patterned, upon which new hypotheses were formulated. The investigation also uncovered as yet unknown conditions of pragmatic and discourse transfer (e.g. awareness in language production) and their interaction. Moreover, the Naturalized Role-play proved to fulfil its aim. It can combine advantages of major methods without their drawbacks and is more effective (i.e. providing more natural data) than existing means of data elicitation. In essence, based on the Naturalized Role-play approach, this investigation sheds new light on the nature of pragmatic and discourse transfer, offers insights into its conditions and features a pioneering creative solution to the controversial methodological problem. The study also presents implications of its findings for second language learners, teachers and native speakers of different languages in social interactions where cultures meet

Dynamic Interactions between Autophagosomes and Lipid Droplets in Chlamydomonas reinhardtii

Autophagy is a highly conserved catabolic process in eukaryotic cells by which waste cellular components are recycled to maintain growth in both favorable and stress conditions. Autophagy has been linked to lipid metabolism in microalgae; however, the mechanism underlying this interaction remains unclear. In this study, transgenic Chlamydomonas reinhardtii cells that stably express the red fluorescent protein (mCherry) tagged-ATG8 as an autophagy marker were established. By using this tool, we were able to follow the autophagy process in live microalgal cells under various conditions. Live-cell and transmission electron microscopy (TEM) imaging revealed physical contacts between lipid droplets and autophagic structures during the early stage of nitrogen starvation, while fusion of these two organelles was observed in prolonged nutritional deficiency, suggesting that an autophagy-related pathway might be involved in lipid droplet turnover in this alga. Our results thus shed light on the interplay between autophagy and lipid metabolism in C. reinhardtii, and this autophagy marker would be a valuable asset for further investigations on autophagic processes in microalgae

Malnutrition among 6–59-Month-Old Children at District 2 Hospital, Ho Chi Minh City, Vietnam: Prevalence and Associated Factors

Objectives. Childhood malnutrition is major health concern in many low- and middle-income countries, including Vietnam. It was a major risk factor for child mortality and adult ill-health. Malnutrition could increase the risk of serious infections; conversely current diseases also had a negative impact on the growth of child. This study, therefore, examines the prevalence of stunting and underweight among 6–59-month-old outpatient children in District 2 Hospital, Ho Chi Minh City, Vietnam. Methods. A cross-sectional study involved a sample of 225 children aged 6–59 months who were randomly selected from the Outpatient Department in District 2 Hospital. Anthropometric measurements and blood test of children were taken to assess the nutritional status and anaemia. A structured questionnaire was also used to collect mothers’ and children’s characteristics to examine associated risk factors. Results. The prevalence of stunting, underweight, overweight, and anaemia among children aged 6–59 months was 9.8%, 8.4%, 25.8%, and 30.7%, respectively. Underweight significantly correlated only to having breastfeeding in the first hour after birth (RR: 0.02; 95% CI: 0.01-0.17; p<0.001), while stunting was related to age of starting complementary foods from equal to/more than 6 months (RR=0.70, 95%CI=0.50-0.99, p<0.05) and normal birth weight (RR = 0.29, 95%CI = 0.15-0.56, p<0.001). Conclusions. This study emphasized the importance of measuring the overall nutritional status for children, who have coexisting infectious diseases and anaemia. The high prevalence of malnutrition and anaemia underlined the need for routine screening as well as treatment of children. Additionally, health information strategies should be focused on young children feeding practices to minimize stunting and underweight

Dynamic Interactions between Autophagosomes and Lipid Droplets in Chlamydomonas reinhardtii

Autophagy is a highly conserved catabolic process in eukaryotic cells by which waste cellular components are recycled to maintain growth in both favorable and stress conditions. Autophagy has been linked to lipid metabolism in microalgae; however, the mechanism underlying this interaction remains unclear. In this study, transgenic Chlamydomonas reinhardtii cells that stably express the red fluorescent protein (mCherry) tagged-ATG8 as an autophagy marker were established. By using this tool, we were able to follow the autophagy process in live microalgal cells under various conditions. Live-cell and transmission electron microscopy (TEM) imaging revealed physical contacts between lipid droplets and autophagic structures during the early stage of nitrogen starvation, while fusion of these two organelles was observed in prolonged nutritional deficiency, suggesting that an autophagy-related pathway might be involved in lipid droplet turnover in this alga. Our results thus shed light on the interplay between autophagy and lipid metabolism in C. reinhardtii, and this autophagy marker would be a valuable asset for further investigations on autophagic processes in microalgae.This research was funded by a grant from Marine Biotechnology Program (20150184) funded by Ministry of Oceans and Fisheries, Korea; by the Advanced Biomass R&D Center (ABC) of Global Frontier Project funded by the Ministry of Science and ICT(ABC-2015M3A6A2065697); and by grant from the Korea Research Institute of Bioscience and Biotechnology (KRIBB) Research Initiative Program (www.kribb.re.kr).Peer reviewe

The ancient phosphatidylinositol 3-kinase signaling system is a master regulator of energy and carbon metabolism in algae

Algae undergo a complete metabolic transformation under stress by arresting cell growth, inducing autophagy and hyperaccumulating biofuel precursors such as triacylglycerols and starch. However, the regulatory mechanisms behind this stress-induced transformation are still unclear. Here, we use biochemical, mutational, and “omics” approaches to demonstrate that PI3K signaling mediates the homeostasis of energy molecules and influences carbon metabolism in algae. In Chlamydomonas reinhardtii, the inhibition and knockdown (KD) of algal class III PI3K led to significantly decreased cell growth, altered cell morphology, and higher lipid and starch contents. Lipid profiling of wild-type and PI3K KD lines showed significantly reduced membrane lipid breakdown under nitrogen starvation (-N) in the KD. RNA-seq and network analyses showed that under -N conditions, the KD line carried out lipogenesis rather than lipid hydrolysis by initiating de novo fatty acid biosynthesis, which was supported by tricarboxylic acid cycle down-regulation and via acetyl-CoA synthesis from glycolysis. Remarkably, autophagic responses did not have primacy over inositide signaling in algae, unlike in mammals and vascular plants. The mutant displayed a fundamental shift in intracellular energy flux, analogous to that in tumor cells. The high free fatty acid levels and reduced mitochondrial ATP generation led to decreased cell viability. These results indicate that the PI3K signal transduction pathway is the metabolic gatekeeper restraining biofuel yields, thus maintaining fitness and viability under stress in algae. This study demonstrates the existence of homeostasis between starch and lipid synthesis controlled by lipid signaling in algae and expands our understanding of such processes, with biotechnological and evolutionary implications.This work was supported by a grant from the host institution through the Korea Research Institute of Bioscience and Biotechnology (KRIBB) Research Initiative Program (www.kribb.re.kr), the Advanced Biomass R&D Center of the Global Frontier Project funded by the Ministry of Science, ICT and Future Planning (2015M3A6A2065697), and a grant from the Marine Biotechnology Program funded by the Ministry of Oceans and Fisheries (20150184)