Hypoxic responses in plants involve Plant Cysteine Oxidases (PCOs). They catalyze the N-terminal cysteine oxidation of Ethylene Response Factors VII (ERF-VII) in an oxygen-dependent manner, leading ...to their degradation via the cysteine N-degron pathway (Cys-NDP) in normoxia. In hypoxia, PCO activity drops, leading to the stabilization of ERF-VIIs and subsequent hypoxic gene upregulation. Thus far, no chemicals have been described to specifically inhibit PCO enzymes. In this work, we devised an in vivo pipeline to discover Cys-NDP effector molecules. Budding yeast expressing AtPCO4 and plant-based ERF-VII reporters was deployed to screen a library of natural-like chemical scaffolds and was further combined with an Arabidopsis Cys-NDP reporter line. This strategy allowed us to identify three PCO inhibitors, two of which were shown to affect PCO activity in vitro. Application of these molecules to Arabidopsis seedlings led to an increase in ERF-VII stability, induction of anaerobic gene expression, and improvement of tolerance to anoxia. By combining a high-throughput heterologous platform and the plant model Arabidopsis, our synthetic pipeline provides a versatile system to study how the Cys-NDP is modulated. Its first application here led to the discovery of at least two hypoxia-mimicking molecules with the potential to impact plant tolerance to low oxygen stress.
Alexandrium minutum is one of several dinoflagellate species capable of producing paralytic shellfish toxins. Previous work suggests that toxin levels are influenced by a number of parameters, ...including dinoflagellate- associated bacteria. In the present study, a toxin-producing culture of A. minutum isolated from Anakoha Bay in the Marlborough Sounds of New Zealand was subjected to an antibiotic treatment regimen designed to eliminate the associated bacteria. Antibiotics used included penicillin, streptomycin, kanamycin and tetracycline (Treatment 1); ciprofloxacin and gentamicin (Treatment 2); and penicillin, streptomycin and ciprofloxacin (Treatment 3). Enzyme immunoassay showed that saxitoxin levels in the A. minutum culture fell significantly following the first round of antibiotic treatment, and this coincided with a large reduction in the associated copiotrophic bacterial population. HPLC data indicated that there was also a reduction in gonyautoxins (GTX sub(1-3)). The oligotrophic population was more difficult to eliminate and required 2 additional rounds of antibiotic treatment, but saxitoxin levels did not change any further. Scanning laser confocal microscopy following acridine orange staining was used to observe intracellular bacteria-like particles, which were considerably reduced by the end of the treatments, probably due to the inclusion of antibiotics that penetrate eukaryotic cells. Algal mean generation times were not significantly affected by the antibiotic treatments. Qualitative and quantitative changes in toxin production coincided with a reduction in the culturable, copiotrophic and/or intracellular bacteria in the A. minutum Anakoha A culture. The premise that bacteria can exert a strong influence on algal toxicity was supported by this study, although the mechanisms remain unknown.
The LISST (Laser In Situ Scattering and Transmissometery) instrument was designed by Sequoia Scientific to measure the particle size distributions and concentrations of sediment suspensions in the ...field environment. To understand the LISST's performance with natural sediments from a variety of marine sources, several experiments were performed to compare the LISST's results to traditional sieving, filtering and weighing techniques. The LISST was able to correctly locate the peak of a unimodal particle size distribution and resolve the two peaks of a bimodal distribution if they are separated by at least 1
φ for sediment sizes of 5 to 250 μm. Unlike a single frequency scattering sensor for sediment concentration, which require sediment size specific calibration constants, the LISST is able to accurately measure sediment concentration with a single calibration constant for varying size distributions within the size range of 5 to 250 μm. The LISST was also found to adequately represent the particle volumetric size distribution for two different samples from marine environments.
In order to study saxitoxin (STX) production by micro-algae in the laboratory, a defined algal culture medium which supports optimum growth over a long time-period is a requirement. In the ...development of such a medium, a number of modifications were made to a standard algal culture medium (GP) and growth of a STX-producing isolate of Alexandrium minutum in the different formulations was assessed by measuring maximum cell densities and mean generation times (MGT). All experiments were carried out under controlled conditions in an aerobic atmosphere with increased CO sub(2). Whilst maximum cell densities in the different modifications were similar, the MGT was significantly shortened by the addition of Tris buffer and the trace metals strontium, selenium and molybdenum. Replacement of natural with artificial seawater and removal of soil extract did not adversely affect algal growth. Five of the six media formulations supported the growth of A. minutum over a 9-month period.
Hydrogen sulphide (H2S), nitric oxide (NO), and carbon monoxide (CO) are involved in transitional microvascular tone dysregulation in the preterm infant; however there is conflicting evidence on the ...interaction of these gasotransmitters, and their overall contribution to the microcirculation in newborns is not known. The aim of this study was to measure the levels of all 3 gasotransmitters, characterise their interrelationships and elucidate their combined effects on microvascular blood flow.
90 preterm neonates were studied at 24h postnatal age. Microvascular studies were performed by laser Doppler. Arterial COHb levels (a measure of CO) were determined through co-oximetry. NO was measured as nitrate and nitrite in urine. H2S was measured as thiosulphate by liquid chromatography. Relationships between levels of the gasotransmitters and microvascular blood flow were assessed through partial correlation controlling for the influence of gestational age. Structural equation modelling was used to examine the combination of these effects on microvascular blood flow and derive a theoretical model of their interactions.
No relationship was observed between NO and CO (p = 0.18, r = 0.18). A positive relationship between NO and H2S (p = 0.008, r = 0.28) and an inverse relationship between CO and H2S (p = 0.01, r = -0.33) exists. Structural equation modelling was used to examine the combination of these effects on microvascular blood flow. The model with the best fit is presented.
The relationships between NO and H2S, and CO and H2S may be of importance in the preterm newborn, particularly as NO levels in males are associated with higher H2S levels and higher microvascular blood flow and CO in females appears to convey protection against vascular dysregulation. Here we present a theoretical model of these interactions and their overall effects on microvascular flow in the preterm newborn, upon which future mechanistic studies may be based.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Excessive vasodilatation during the perinatal period is associated with cardiorespiratory instability in preterm neonates. Little evidence of the mechanisms controlling microvascular tone during ...circulatory transition exists. We hypothesised that hydrogen sulphide (H2S), an important regulator of microvascular reactivity and central cardiac function in adults and animal models, may contribute to the vasodilatation observed in preterm newborns. Term and preterm neonates (24-43 weeks gestational age) were studied. Peripheral microvascular blood flow was assessed by laser Doppler. Thiosulphate, a urinary metabolite of H2S, was determined by high performance liquid chromatography as a measure of 24 hr total body H2S turnover for the first 3 days of postnatal life. H2S turnover was greatest in very preterm infants and decreased with increasing gestational age (p = 0.0001). H2S turnover was stable across the first 72 hrs of life in older neonates. In very preterm neonates, H2S turnover increased significantly from day 1 to 3 (p =0.0001); and males had higher H2S turnover than females (p = 0.04). A significant relationship between microvascular blood flow and H2S turnover was observed on day 2 of postnatal life (p = 0.0004). H2S may play a role in maintaining microvascular tone in the perinatal period. Neonates at the greatest risk of microvascular dysfunction characterised by inappropriate peripheral vasodilatation--very preterm male neonates--are also the neonates with highest levels of total body H2S turnover suggesting that overproduction of this gasotransmitter may contribute to microvascular dysfunction in preterms. Potentially, H2S is a target to selectively control microvascular tone in the circulation of newborns.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This paper reports interviews conducted with twenty children and young people adopted from the care system in England, exploring their experiences and views of their life storybooks and examines the ...role of life storybooks as a form of narrative that contributes to identity development. Despite being a widely used intervention in direct social work practice in England and enshrined as a requirement in law for all looked after children placed for adoption there is little known about how children experience their life storybooks. The data revealed three core themes related to the child's story, identity and communicative openness. These themes provide insights from the children about the levels of honesty in the narrative conveyed, concerns about gaps in their biographies, the importance of treasured material possessions alongside their book, their adoptive identity and the importance of different levels of openness in discussions about their adoptive status. There are a number of important practice implications outlined, as well as an identified need for more research on this topic.
•We explore adopted children and young people's experiences of life storybooks.•Life storybooks as contributing to narrative identity are problematized.•Core themes to emerge — the child’s story, identity and communicative openness.•Children value life storybooks but are critical of quality, gaps and lack of narrative.•Data reveal a pressing need to improve training in producing and using life storybooks.
BackgroundThe shift towards Open Science means that there is an increasing expectation amongst funders and publishers of health and social care research in the UK that all data be made available for ...re-use. This expectation is, in large part, modelled on established quantitative data sharing practices. This potentially raises ethical, theoretical, methodological and practical challenges for the sharing and secondary analysis of qualitative data within health and social care research.AimTo explore key stakeholders’ views on qualitative data sharing and re-use in health and social care research.MethodsOne-to-one qualitative interviews and focus group discussions were conducted with researchers, data librarians/managers, funders, experts in research ethics and information governance, and participants in qualitative research. Interviews/focus groups explored ethical, theoretical, methodological and practical issues related to qualitative data sharing and re-use, including concerns around data security and trust, and practicalities of data sharing.FindingsStakeholders described qualitative data sharing and re-use as ethically valuable in terms of maximising the value of primary data. Stakeholders discussed key motivators, including altruism, accessibility of a range of data (particularly for early career researchers and students), and generating research impact through data re-use. Concerns were expressed in relation to obtaining ‘informed’ consent, data security and access, workloads associated with the anonymisation of qualitative data, and the quality of available data including meta-data to aid contextual understanding of datasets. The ethical and methodological challenges of doing qualitative secondary analysis were also discussed.ConclusionsA move towards sharing qualitative data requires engagement with the research community, including those who have contributed their data to research, to mitigate identified obstacles while enhancing existing motivations to both share data and to seek out data for secondary analysis.
This research, conducted jointly between the UK children’s charity Coram and the University of Bristol, aimed to address the absence in the academic literature of adopters’ perspectives on their ...children’s life story books. Forty adopters from England and Wales participated in either focus group or telephone interviews. While some of the accounts were of positive experiences, there was a broad consensus that many books were of poor quality, children had been inadequately prepared to explore their histories, adoption professionals and agencies did not seem to prioritise life story books, and that adopters felt poorly prepared in how to use and update them for the benefit of their children. Clear messages for adoption agencies can be elicited regarding the preparation and use of life story books, such as improved training for professionals, monitoring of the quality of books produced and better access to support and guidance for adopters to engage in this crucial work with their children over time.
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