Defining the core microbiome of the symbiotic dinoflagellate, Symbiodinium

© 2017 Society for Applied Microbiology and John Wiley & Sons Ltd Dinoflagellates of the genus Symbiodinium underpin the survival and ecological success of corals. The use of cultured strains has been particularly important to disentangle the complex life history of Symbiodinium and their contribution to coral host physiology. However, these cultures typically harbour abundant bacterial communities which likely play important, but currently unknown, roles in Symbiodinium biology. We characterized the bacterial communities living in association with a wide phylogenetic diversity of Symbiodinium cultures (18 types spanning 5 clades) to define the core Symbiodinium microbiome. Similar to other systems, bacteria were nearly two orders of magnitude more numerically abundant than Symbiodinium cells and we identified three operational taxonomic units (OTUs) which were present in all cultures. These represented the α-proteobacterium Labrenzia and the γ-proteobacteria Marinobacter and Chromatiaceae. Based on the abundance and functional potential of bacteria harboured in these cultures, their contribution to Symbiodinium physiology can no longer be ignored

Importance of Fluctuations in Light on Plant Photosynthetic Acclimation

The acclimation of plants to light has been studied extensively, yet little is known about the effect of dynamic fluctuations in light on plant phenotype and acclimatory responses. We mimicked natural fluctuations in light over a diurnal period to examine the effect on the photosynthetic processes and growth of Arabidopsis (Arabidopsis thaliana). High and low light intensities, delivered via a realistic dynamic fluctuating or square wave pattern, were used to grow and assess plants. Plants subjected to square wave light had thicker leaves and greater photosynthetic capacity compared with fluctuating light-grown plants. This, together with elevated levels of proteins associated with electron transport, indicates greater investment in leaf structural components and photosynthetic processes. In contrast, plants grown under fluctuating light had thinner leaves, lower leaf light absorption, but maintained similar photosynthetic rates per unit leaf area to square wave-grown plants. Despite high light use efficiency, plants grown under fluctuating light had a slow growth rate early in development, likely due to the fact that plants grown under fluctuating conditions were not able to fully utilize the light energy absorbed for carbon fixation. Diurnal leaf-level measurements revealed a negative feedback control of photosynthesis, resulting in a decrease in total diurnal carbon assimilated of at least 20%. These findings highlight that growing plants under square wave growth conditions ultimately fails to predict plant performance under realistic light regimes and stress the importance of considering fluctuations in incident light in future experiments that aim to infer plant productivity under natural conditions in the field

Overexpression of Plastid Transketolase in Tobacco Results in a Thiamine Auxotrophic Phenotype

To investigate the effect of increased plastid transketolase on photosynthetic capacity and growth, tobacco (Nicotiana tabacum) plants with increased levels of transketolase protein were produced. This was achieved using a cassette composed of a full-length Arabidopsis thaliana transketolase cDNA under the control of the cauliflower mosaic virus 35S promoter. The results revealed a major and unexpected effect of plastid transketolase overexpression as the transgenic tobacco plants exhibited a slow-growth phenotype and chlorotic phenotype. These phenotypes were complemented by germinating the seeds of transketolase-overexpressing lines in media containing either thiamine pyrophosphate or thiamine. Thiamine levels in the seeds and cotyledons were lower in transketolase-overexpressing lines than in wild-type plants. When transketolase-overexpressing plants were supplemented with thiamine or thiamine pyrophosphate throughout the life cycle, they grew normally and the seed produced from these plants generated plants that did not have a growth or chlorotic phenotype. Our results reveal the crucial importance of the level of transketolase activity to provide the precursor for synthesis of intermediates and to enable plants to produce thiamine and thiamine pyrophosphate for growth and development. The mechanism determining transketolase protein levels remains to be elucidated, but the data presented provide evidence that this may contribute to the complex regulatory mechanisms maintaining thiamine homeostasis in plants

Risk Factors for Heart Failure 20-Year Population-Based Trends by Sex, Socioeconomic Status, and Ethnicity

Background: There are multiple risk factors for heart failure, but contemporary temporal trends according to sex, socioeconomic status, and ethnicity are unknown. Methods: Using a national UK general practice database linked to hospitalizations (1998-2017), 108 638 incident heart failure patients were identified. Differences in risk factors among patient groups adjusted for sociodemographic factors and age-adjusted temporal trends were investigated using logistic and linear regression. Results: Over time, a 5.3 year (95% CI, 5.2-5.5) age difference between men and women remained. Women had higher blood pressure, body mass index, and cholesterol than men (P<0.0001). Ischemic heart disease prevalence increased for all to 2006 before reducing in women by 0.5% per annum, reaching 42.7% (95% CI, 41.7-43.6), but not in men, remaining at 57.7% (95% CI, 56.9-58.6; interaction P=0.002). Diabetes mellitus prevalence increased more in men than in women (interaction P<0.0001). Age between the most deprived (74.6 years [95% CI, 74.1-75.1]) and most affluent (79.9 [95% CI, 79.6-80.2]) diverged (interaction P<0.0001), generating a 5-year gap. The most deprived had significantly higher annual increases in comorbidity numbers (+0.14 versus +0.11), body mass index (+0.14 versus +0.11 kg/m(2)), and lower smoking reductions (-1.2% versus -1.7%) than the most affluent. Ethnicity trend differences were insignificant, but South Asians were overall 6 years and the black group 9 years younger than whites. South Asians had more ischemic heart disease (+16.5% [95% CI, 14.3-18.6]), hypertension (+12.5% [95% CI, 10.5-14.3]), and diabetes mellitus (+24.3% [95% CI, 22.0-26.6]), and the black group had more hypertension (+12.3% [95% CI, 9.7-14.8]) and diabetes mellitus (+13.1% [95% CI, 10.1-16.0]) but lower ischemic heart disease (-10.6% [95% CI, -13.6 to -7.6]) than the white group. Conclusions: Population groups show distinct risk factor trend differences, indicating the need for contemporary tailored prevention programs

The Volatilomes of Symbiodiniaceae-Associated Bacteria Are Influenced by Chemicals Derived From Their Algal Partner

© Copyright © 2020 Lawson, Seymour, Possell, Suggett and Raina. Biogenic volatile organic compounds (BVOCs) are a large group of molecules involved in trophic interactions, stress response and atmospheric chemistry. Although they have been extensively studied in terrestrial ecosystems, their identity and prevalence in the marine environment remains largely unexplored. Here we characterized the volatilome of two abundant marine bacteria that were previously identified as members of the core microbiome of Symbiodiniaceae (phylum: Dinoflagellata), the photosynthetic endosymbionts of reef building corals. To determine the influence of Symbiodiniaceae exudate on their associated bacteria, we incubated isolates of Marinobacter adhaerens HP15 and Labrenzia sp. 21p with Symbiodiniaceae culture filtrate or culture medium (control) and investigated their volatilomes using GC–MS. The volatilome of Labrenzia sp. incubated in Symbiodiniaceae filtrate was significantly different and more diverse relative to the control. In contrast, the overall composition of the M. adhaerens volatilomes were consistent between treatment and control. Among the 35 compounds detected in both bacterial species, the dominant chemical functional groups were halogenated hydrocarbons, aromatic hydrocarbons and organosulfurs, some of which are known to play roles in inter-organism signaling, to act as antioxidants and as antimicrobials. This study provides new insights into the potential sources and diversity of marine BVOCs, uncovering a wide range of molecules that may play important physiological and ecological roles for these organisms, while also revealing the role of Symbiodiniaceae-associated bacteria in the emission of important atmospheric gases

Obesity, Ethnicity, and Risk of Critical Care, Mechanical Ventilation, and Mortality in Patients Admitted to Hospital with COVID-19: Analysis of the ISARIC CCP-UK Cohort

OBJECTIVE: The aim of this study was to investigate the association of obesity with in-hospital coronavirus disease 2019 (COVID-19) outcomes in different ethnic groups. METHODS: Patients admitted to hospital with COVID-19 in the United Kingdom through the Clinical Characterisation Protocol UK (CCP-UK) developed by the International Severe Acute Respiratory and emerging Infections Consortium (ISARIC) were included from February 6 to October 12, 2020. Ethnicity was classified as White, South Asian, Black, and other minority ethnic groups. Outcomes were admission to critical care, mechanical ventilation, and in-hospital mortality, adjusted for age, sex, and chronic diseases. RESULTS: Of the participants included, 54,254 (age = 76 years; 45.0% women) were White, 3,728 (57 years; 41.1% women) were South Asian, 2,523 (58 years; 44.9% women) were Black, and 5,427 (61 years; 40.8% women) were other ethnicities. Obesity was associated with all outcomes in all ethnic groups, with associations strongest for black ethnicities. When stratified by ethnicity and obesity status, the odds ratios for admission to critical care, mechanical ventilation, and mortality in black ethnicities with obesity were 3.91 (3.13-4.88), 5.03 (3.94-6.63), and 1.93 (1.49-2.51), respectively, compared with White ethnicities without obesity. CONCLUSIONS: Obesity was associated with an elevated risk of in-hospital COVID-19 outcomes in all ethnic groups, with associations strongest in Black ethnicities

Planning for success: Why conservation programs need a strategic program for recovering species

A substantial amount of money has been spent globally on threatened species management. While the number of threatened species continues to increase, we would expect to observe a portion of those receiving active management to respond positively and recover over time. Management of these recovering species requires a different approach to those which are declining. In particular, recovering species may require active monitoring as the primary management activity, once the threats causing their initial decline have been managed such that populations are stable or increasing. When prioritizing funding actions to improve species persistence (in particular with species prioritization approaches such as cost‐effectiveness rankings), we demonstrate that monitoring species to track their continued improvement would only occur in the (unlikely) scenario of comprehensive program funding. We provide one easily implemented solution to this - the establishment of a separately funded transitional management stream within which recovering or recovered species are prioritized for monitoring from a dedicated monitoring budget. We present a set of criteria to assess recovering species eligible for this management arrangement and demonstrate the successful application of this approach in New South Wales, Australia in the Saving our Species program