Protein-responsive ribozyme switches in eukaryotic cells

Genetic devices that directly detect and respond to intracellular concentrations of proteins are important synthetic biology tools, supporting the design of biological systems that target, respond to or alter specific cellular states. Here, we develop ribozyme-based devices that respond to protein ligands in two eukaryotic hosts, yeast and mammalian cells, to regulate the expression of a gene of interest. Our devices allow for both gene-ON and gene-OFF response upon sensing the protein ligand. As part of our design process, we describe an in vitro characterization pipeline for prescreening device designs to identify promising candidates for in vivo testing. The in vivo gene-regulatory activities in the two types of eukaryotic cells correlate with in vitro cleavage activities determined at different physiologically relevant magnesium concentrations. Finally, localization studies with the ligand demonstrate that ribozyme switches respond to ligands present in the nucleus and/or cytoplasm, providing new insight into their mechanism of action. By extending the sensing capabilities of this important class of gene-regulatory device, our work supports the implementation of ribozyme-based devices in applications requiring the detection of protein biomarkers

Not just a migration problem: Metapopulations, habitat shifts and gene flow are also important for fishway science and management

Worldwide, fishways are increasingly criticized for failing to meet conservation goals. We argue that this is largely due to the dominance of diadromous species of the Northern Hemisphere (e.g., Salmonidae) in the research that underpins the concepts and methods of fishway science and management. With highly diverse life histories, swimming abilities and spatial ecologies, most freshwater fish species do not conform to the stereotype imposed by this framework. This is leading to a global proliferation of fishways that are often unsuitable for native species. The vast majority of fish populations do not undertake extensive migrations between clearly separated critical habitats, yet the movement of individuals and the genetic information they carry is critically important for population viability. We briefly review some of the latest advances in spatial ecological modelling for dendritic networks to better define what it means to achieve effective fish passage at a barrier. Through a combination of critical habitat assessment and the modelling of metapopulations, climate change�driven habitat shifts, and adaptive gene flow, we recommend a conceptual and methodological framework for fishway target�setting and monitoring suitable for a wide range of species. In the process, we raise a number of issues that should contribute to the ongoing debate about fish passage research and the design and monitoring of fishways

Repeat placental growth factor-based testing in women with suspected preterm pre-eclampsia (PARROT-2): a multicentre, parallel-group, superiority, randomised controlled trial.

BackgroundPlacental growth factor (PlGF)-based testing has high diagnostic accuracy for predicting pre-eclampsia needing delivery, significantly reducing time to diagnosis and severe maternal adverse outcomes. The clinical benefit of repeat PlGF-based testing is unclear. We aimed to determine whether repeat PlGF-based testing (using a clinical management algorithm and nationally recommended thresholds) reduces adverse perinatal outcomes in pregnant individuals with suspected preterm pre-eclampsia.MethodsIn this multicentre, parallel-group, superiority, randomised controlled trial, done in 22 maternity units across England, Scotland, and Wales, we recruited women aged 18 years or older with suspected pre-eclampsia between 22 weeks and 0 days of gestation and 35 weeks and 6 days of gestation. Women were randomly assigned (1:1) to revealed repeat PlGF-based testing or concealed repeat testing with usual care. The intervention was not masked to women or partners, or clinicians or data collectors, due to the nature of the trial. The trial statistician was masked to intervention allocation. The primary outcome was a perinatal composite of stillbirth, early neonatal death, or neonatal unit admission. The primary analysis was by the intention-to-treat principle, with a per-protocol analysis restricted to women managed according to their allocation group. The trial was prospectively registered with the ISRCTN registry, ISRCTN 85912420.FindingsBetween Dec 17, 2019, and Sept 30, 2022, 1253 pregnant women were recruited and randomly assigned treatment; one patient was excluded due to randomisation error. 625 women were allocated to revealed repeat PlGF-based testing and 627 women were allocated to usual care with concealed repeat PlGF-based testing (mean age 32·3 [SD 5·7] years; 879 [70%] white). One woman in the concealed repeat PlGF-based testing group was lost to follow-up. There was no significant difference in the primary perinatal composite outcome between the revealed repeat PlGF-based testing group (195 [31·2%]) of 625 women) compared with the concealed repeat PlGF-based testing group (174 [27·8%] of 626 women; relative risk 1·21 [95% CI 0·95-1·33]; p=0·18). The results from the per-protocol analysis were similar. There were four serious adverse events in the revealed repeat PlGF-based testing group and six in the concealed repeat PlGF-based testing group; all serious adverse events were deemed unrelated to the intervention by the site principal investigators and chief investigator.InterpretationRepeat PlGF-based testing in pregnant women with suspected pre-eclampsia was not associated with improved perinatal outcomes. In a high-income setting with a low prevalence of adverse outcomes, universal, routine repeat PlGF-based testing of all individuals with suspected pre-eclampsia is not recommended.FundingTommy's Charity, Jon Moulton Charitable Trust, and National Institute for Health and Care Research Guy's and St Thomas' Biomedical Research Centre

International Olympic Committee consensus statement on pain management in elite athletes

Pain is a common problem among elite athletes and is frequently associated with sport injury. Both pain and injury interfere with the performance of elite athletes. There are currently no evidence-based or consensus-based guidelines for the management of pain in elite athletes. Typically, pain management consists of the provision of analgesics, rest and physical therapy. More appropriately, a treatment strategy should address all contributors to pain including underlying pathophysiology, biomechanical abnormalities and psychosocial issues, and should employ therapies providing optimal benefit and minimal harm. To advance the development of a more standardised, evidence-informed approach to pain management in elite athletes, an IOC Consensus Group critically evaluated the current state of the science and practice of pain management in sport and prepared recommendations for a more unified approach to this important topic

Experimental quantification of the response of fish to conditions associated with low-head hydropower and fish passage facilities

This thesis assessed the impact of a novel low-head hydropower device, the Hydrostatic Pressure Converter (HPC), on downstream moving fish, and investigated factors that may limit both up- and down-stream fish pass efficiency. This was achieved through the use of a blade strike model (BSM) and experimental studies conducted in large open channel flumes. A BSM predicted a lower probability of strike with a HPC blade for small fish that travelled downstream faster, and when blades rotated slowly. A major pinch-point between the blade tips and the base of the flume caused severe damage to euthanized brown trout (Salmo trutta) as they passively drifted through a prototype HPC. Damage ranged from abrasive scale loss to skeletal deformation and breakage. Rainbow trout (Oncorhynchus mykiss) and European eel (Anguilla anguilla) did not exhibit avoidance behaviours when approaching the intake to a HPC located within a flume. When behavioural data (speed of downstream movement and orientation) were incorporated into BSM simulations, probability of strike increased and decreased for trout and eel, respectively, compared with an assumption of passive drift with bulk flow. Species specific behaviours influenced probability and severity of strike with a HPC blade. Management recommendations are made to ensure HPC developments meet the required environmental standards. Ensuring efficient fish passage around low-head hydropower developments presents a major ecological challenge. Behavioural data on individual fish encountering conditions ubiquitous to fish pass structures was used to investigate and identify factors that may limit passage efficiencies. Although upstream migrant adult river lamprey (Lampetra fluviatilis), a species of conservation concern in Europe, were predicted to avoid areas of elevated turbulence, little evidence in support of this was found. Instead lamprey appeared to alter their migration strategy based primarily on water velocity. Behaviours were indicative of a time conservation strategy, i.e. altering behaviour to expedite passage through energetically expensive environments. For downstream moving fish, delay due to avoidance of conditions created at bypass entrances (e.g. abrupt accelerations of velocity) can negatively impact fitness. Velocity gradients created by a constricted flume section had a clear influence over downstream moving brown trout. Avoidance behaviours occurred at a similar threshold spatial velocity gradient when dark (ca. 0.4 cm s-1 cm-1), and the addition of a light stimulus served to reduce this threshold by approximately 50%. Elevated avoidance to velocity gradients was also evident when downstream migrant juvenile salmon (Oncorhynchus tshawytscha) were able to navigate using mechanosensory and visual senses. Avoidance behaviour significantly impacted subsequent rate of passage. Information provided in this thesis significantly enhances our understanding of how fish respond to environmental stimuli, has direct application to fish passage, and the potential to improve fish survival at low-head hydropower developments

London Surgeon Traces Guelph\u27s Research Role in Coagulation

Modern doctors and their patients whose lives depend on therapies used routinely in cardiovascular and transplant surgery owe a debt to a handful of coagulation pioneers whose discoveries during the 1920s took place not at medical schools but at the forerunners of the University of Guelph. That\u27s the thesis of a journal review article written by a Canadian transplant surgeon about what he calls a little-known connection between modern clinical medicine and early research in agricultural and veterinary sciences done in Guelph. �The science of agriculture and the science of humans � they\u27re all related,� says Dr. Vivian McAlister, a surgeon at University Hospital in London and a surgery professor at the University of Western Ontario. His paper chase, including an examination of documents held in the McLaughlin Library archives, unearthed work done by several researchers � including two major names in the history of the Ontario Agricultural College and the Ontario Veterinary College � decades before U of G itself was established. McAlister\u27s paper, now before the Canadian Medical Association Journal for review, details how early OAC and OVC studies played a role in the development of anti-clotting agents, specifically vitamin K, heparin and warfarin. More than that, he found that early Guelph researchers pioneered systematic agricultural studies, including the use of controlled trials, a concept that wouldn\u27t catch on in human medicine until later. �They were ahead of medicine,� he says. In his paper, called �Control of Coagulation: A Gift of Canadian Agriculture,� McAlister explains that vitamin K was named in 1935 by a Danish researcher who would later share a Nobel Prize. But that work stemmed from research by a trio of OAC graduate students. William McFarlane had studied dairy science in his native United Kingdom; in Canada, he completed a PhD on poultry in 1932 under the supervision of Prof. William Graham. (McFarlane subsequently left for Edmonton but returned to Guelph as a chemistry professor in Macdonald College.) Along with students William Graham Jr. and Frederick Richardson, McFarlane published a paper in 1930 about experiments on fat-soluble components of chick feed. Working with chicks on a fat-free diet, they noticed persistent bleeding from wounds where the birds\u27 identification tags had been applied. Having ruled out known vitamins and other dietary components, they were left with the possibility that an unknown component prevented blood clotting. Interested mostly in comparing various dietary supplements and chick growth, the trio went no further. But in a 1943 Nobel Prize lecture given by Copenhagen researcher Henrik Dam, they were credited with the initial observation that led to the discovery of vitamin K. Other researchers mistakenly believed that vitamin C was the missing ingredient. Dam found an anti-hemorrhagic factor in other foods and named it vitamin K for �koagulation� in Scandinavian and German spellings. American researcher Edward Doisey extracted, characterized and synthesized vitamin K from alfalfa. McAlister\u27s paper notes that vitamin K soon became available for treating patients who were bleeding or needed surgery. Dam and Doisey shared the 1943 Nobel Prize in Physiology or Medicine. But that was only part of the Guelph connection to the coagulation story � and not even the first part. McAlister says neither Dam nor other vitamin researchers knew that vitamin K antagonists had been studied almost a decade earlier, this time at OVC. Dam had shown how the body uses vitamin K to make prothrombin, a precursor in the chain of biochemical events that leads to fibrin, a vital clotting protein. In his Nobel address, he also mentioned that this chain of events could be disrupted by dicoumarol. This substance interferes with vitamin K metabolism, slowing the production of prothrombin. The precursor to dicoumarol forms in sweet clover that has been spoilt by mould. But nobody knew that back when Francis Schofield, a 1910 OVC graduate and pathologist at the veterinary college, began looking at a bleeding disorder that caused cattle to hemorrhage to death. In 1922, he traced the problem to mouldy sweet clover. He suggested that an anti-thrombin substance in spoilt silage led to uncontrolled bleeding. Two decades would pass before scientists figured out how the process worked. It was researchers at the University of Wisconsin who found that mould oxidized coumarin in clover. Yoked to formaldehyde, coumarin formed dicoumarol, a vitamin K antagonist. Those scientists had uncovered a substance that would become a powerful anticoagulant. A derivative became warfarin, named for the acronym of the Wisconsin Alumni Research Fund. Used originally as a rodent pesticide, warfarin � along with dicoumarol � found use in human medicine, not least after then U.S. president Dwight Eisenhower was treated with it after a heart attack. McAlister\u27s paper also details how Toronto scientists Charles Best, Gordon Murray and Louis Jaques found a cheap, abundant source of purified heparin that could be used in vascular surgery. McAlister says many liver transplant recipients now receive vitamin K, warfarin or heparin during their care. He first uncovered the Guelph connections more than five years ago, when he was preparing a talk on coagulation and hemorrhage control, including a new drug made in Denmark. He already knew about Dam\u27s work there on vitamin K, but he was searching for more information to strengthen the link to Copenhagen. �What I was astonished to see was that Dam credited scientists in Guelph with the preliminary work that allowed him to do his Nobel Prize-winning work.� Curious, he followed up the reference at the McLaughlin Library archives (his paper credits help from archivist Darlene Wiltsie). He sent his review paper to CMAJ about a year ago. Speaking about the early Guelph research, he says: �The most important message is that these are not isolated matters of luck. This was a planned approach arising out of a 19-century decision to have an agricultural and a veterinary college in Guelph supported by the Government of Ontario. That link was, I think, essential to its success. It gave scientists credibility in the community.� That point was underlined when his preliminary research on McFarlane led him to the elder William Graham, for whom the former poultry building on campus is named. Although he had nothing to do with studies of bleeding chicks on fat-free diets, Graham Sr. fostered a climate of inquiry that enabled other researchers, including his son, to thrive, says McAlister. For McAlister, the U of G connection to the story of coagulation is bittersweet. McFarlane and his collaborators knew that a fat-soluble component of the diet was responsible for clotting failure, but they left that research avenue untrodden. �If they had pursued it, they would have figured it out. They would have got the Nobel Prize.� Similarly for Schofield, McAlister says, although for different reasons. Pointing to the range of research papers the OVC scientist wrote on infectious diseases in farm animals, McAlister suggests Schofield might have earned a Nobel, too, if he\u27d stuck to hemorrhagic factors. Similar sentiments were expressed in a short biography published last year by Douglas Maplesden. He wrote that Schofield\u27s �early discovery of an anticoagulant active via the oral route was one of the most important discoveries of the veterinary profession in the first half of the 20th century. Oral anticoagulants could thereby be developed to poison rodent pests and as human drugs to prevent thrombosis.� More lyrically, David Archibald, a U of G grad and composer/playwright, retold Schofield\u27s story in a musical portrait called Schofield: The Sleepless Tiger. One song, called The Ballad of Mouldy Sweet Clover, ends with the discovery of warfarin in Wisconsin as follows: �. . . when my bones are still and spent/They\u27ll say there lies the man who sent/A million bleedin\u27 rodents to their grave.

Data and supplementary material: Improvements in upstream passage of European eel and river lamprey at an experimental Crump weir through provision of horizontally and vertically oriented studded tiles

Trial data from a study to assess European eel and river lamprey passage at an experimental gauging weir with and without vertically and horizontally oriented studded tiles. Hydraulic data of the treatments and some supplementary video clips illustrating fish behaviour are also provided. This data accompanies the article: Andrew S. Vowles, Andrew M. Don, Perikles Karageorgopoulos and Paul S. Kemp (2017): Passage of European eel and river lamprey at a model weir provisioned with studded tiles, Journal of Ecohydraulics, http://dx.doi.org/10.1080/24705357.2017.1310001</span