RESUMEN
Increasing crop yields through plant breeding is time consuming and laborious, with the generation of novel combinations of alleles being limited by chromosomal linkage blocks and linkage-drag. Meiotic recombination is essential to create novel genetic variation via the reshuffling of parental alleles. The exchange of genetic information between homologous chromosomes occurs at crossover (CO) sites but CO frequency is often low and unevenly distributed. This bias creates the problem of linkage-drag in recombination 'cold' regions, where undesirable variation remains linked to useful traits. In plants, programmed meiosis-specific DNA double-strand breaks, catalysed by the SPO11 complex, initiate the recombination pathway, although only ~5% result in the formation of COs. To study the role of SPO11-1 in wheat meiosis, and as a prelude to manipulation, we used CRISPR/Cas9 to generate edits in all three SPO11-1 homoeologues of hexaploid wheat. Characterization of progeny lines shows plants deficient in all six SPO11-1 copies fail to undergo chromosome synapsis, lack COs and are sterile. In contrast, lines carrying a single copy of any one of the three wild-type homoeologues are phenotypically indistinguishable from unedited plants both in terms of vegetative growth and fertility. However, cytogenetic analysis of the edited plants suggests that homoeologues differ in their ability to generate COs and in the dynamics of synapsis. In addition, we show that the transformation of wheat mutants carrying six edited copies of SPO11-1 with the TaSPO11-1B gene, restores synapsis, CO formation, and fertility and hence opens a route to modifying recombination in this agronomically important crop.
Asunto(s)
Sistemas CRISPR-Cas , Triticum , Triticum/genética , Sistemas CRISPR-Cas/genética , Fitomejoramiento , Cromosomas , Meiosis/genéticaRESUMEN
Cadaveric dissection is widely used in anatomy teaching worldwide. This method develops anatomical knowledge and practical dissection skills, as well as communication and team working. At the School of Anatomy, University of Bristol, two of our undergraduate units depend on dissection as a teaching tool.Social distancing guidelines brought about by COVID-19 brought challenges and meant it was not possible for all students to be present around a cadaver simultaneously. We adapted with secure, two-way live streaming, facilitated by ceiling-mounted cameras.Our units utilised the technology in slightly different ways. In a larger cohort, students were not able to attend the dissection room simultaneously and 2-4 students from each group attended, with the remainder (6-8 students) attending via Zoom. In the smaller cohort, all students attended, though only two students could be present around the cadaver, with Zoom used to stream the dissection to those distanced around the room. Those present narrated and ensured visibility of the dissection, whilst posing questions to those at home. The home group provided feedback, generated discussion, and conducted research.This chapter reflects on our experiences using this innovative teaching method. It was a valuable alternative to being in person. Whilst students might have spent less time in the dissection room, their dissection time equalled or was greater than pre-pandemic. Students developed digital confidence and built cohorts, and whilst we reflect on the need for effective communication and digital equity, we offer our best practice and solutions.Whilst in-person teaching has resumed in 2021-2022, investment in this technology enables us to rapidly pivot to a reduced in-person, or an entirely online delivery where required, and we are confident that our delivery will be effective in either case. There are also exciting opportunities for new forms of delivery as well as national and international collaborations.
Asunto(s)
COVID-19 , Educación de Pregrado en Medicina , Estudiantes de Medicina , Humanos , Curriculum , Aprendizaje , COVID-19/epidemiología , COVID-19/prevención & control , Control de Enfermedades Transmisibles , CadáverRESUMEN
Free asparagine is the precursor for acrylamide, which forms during the baking, toasting and high-temperature processing of foods made from wheat. In this study, CRISPR/Cas9 was used to knock out the asparagine synthetase gene, TaASN2, of wheat (Triticum aestivum) cv. Cadenza. A 4-gRNA polycistronic gene was introduced into wheat embryos by particle bombardment and plants were regenerated. T1 plants derived from 11 of 14 T0 plants were shown to carry edits. Most edits were deletions (up to 173 base pairs), but there were also some single base pair insertions and substitutions. Editing continued beyond the T1 generation. Free asparagine concentrations in the grain of plants carrying edits in all six TaASN2 alleles (both alleles in each genome) were substantially reduced compared with wildtype, with one plant showing a more than 90 % reduction in the T2 seeds. A plant containing edits only in the A genome alleles showed a smaller reduction in free asparagine concentration in the grain, but the concentration was still lower than in wildtype. Free asparagine concentration in the edited plants was also reduced as a proportion of the free amino acid pool. Free asparagine concentration in the T3 seeds remained substantially lower in the edited lines than wildtype, although it was higher than in the T2 seeds, possibly due to stress. In contrast, the concentrations of free glutamine, glutamate and aspartate were all higher in the edited lines than wildtype. Low asparagine seeds showed poor germination but this could be overcome by exogenous application of asparagine.
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Aspartatoamoníaco Ligasa , Triticum , Asparagina/metabolismo , Aspartatoamoníaco Ligasa/genética , Sistemas CRISPR-Cas/genética , Grano Comestible/metabolismo , Edición Génica , Triticum/genética , Triticum/metabolismoRESUMEN
MAIN CONCLUSION: Methyl-jasmonate induces large increases in p-coumarate linked to arabinoxylan in Brachypodium and in abundance of GT61 and BAHD family transcripts consistent with a role in synthesis of this linkage. Jasmonic acid (JA) signalling is required for many stress responses in plants, inducing large changes in the transcriptome, including up-regulation of transcripts associated with lignification. However, less is known about the response to JA of grass cell walls and the monocot-specific features of arabinoxylan (AX) synthesis and acylation by ferulic acid (FA) and para-coumaric acid (pCA). Here, we show that methyl-jasmonate (MeJA) induces moderate increases in FA monomer, > 50% increases in FA dimers, and five-sixfold increases in pCA ester-linked to cell walls in Brachypodium callus. Direct measurement of arabinose acylated by pCA (Araf-pCA) indicated that most or all the increase in cell-wall pCA was due to pCA ester-linked to AX. Analysis of the RNA-seq transcriptome of the callus response showed that these cell-wall changes were accompanied by up-regulation of members of the GT61 and BAHD gene families implicated in AX decoration and acylation; two BAHD paralogues were among the most up-regulated cell-wall genes (seven and fivefold) after 24 h exposure to MeJA. Similar responses to JA of orthologous BAHD and GT61 transcripts are present in the RiceXPro public expression data set for rice seedlings, showing that they are not specific to Brachypodium or to callus. The large response of AX-pCA to MeJA may, therefore, indicate an important role for this linkage in response of primary cell walls of grasses to JA signalling.
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Acetatos/farmacología , Brachypodium/efectos de los fármacos , Pared Celular/efectos de los fármacos , Ciclopentanos/farmacología , Oxilipinas/farmacología , Reguladores del Crecimiento de las Plantas/farmacología , Transcriptoma/efectos de los fármacos , Brachypodium/genética , Brachypodium/metabolismo , Pared Celular/química , Relación Dosis-Respuesta a Droga , Perfilación de la Expresión Génica , Genes de Plantas/genética , Hidroxibenzoatos/análisis , Redes y Vías Metabólicas/efectos de los fármacos , Filogenia , ARN de Planta/genética , Transcriptoma/genéticaRESUMEN
At the University of Bristol, we established a novel dissection course to complement our anatomy degree. Students enrolled in this undergraduate course are trained as comparative anatomists, with equal time given to both human and veterinary anatomy. Historically, students opted to dissect either human or veterinary donors as part of the course. To fully reflect the comparative nature of the degree, the dissection course was redesigned so students could dissect both human and veterinary specimens as part of the same course. This facilitated a wide-ranging experience of anatomy, encouraging detailed knowledge of a multitude of species and allowing for multifaceted anatomy graduates to be ready for employment in a wide and competitive job market. Across three iterations of the amended version of the course, median marks ranged from 58.7% to 62.0%, with between 22 and 39 students enrolled. In comparison to the course prior to the introduction of the change, median marks ranged from 59.8% to 62.8%, with between 16 and 24 students enrolled. There was no significant difference between marks before or after the introduction of the concurrently comparative aspect. This paper describes the course, with learning materials and assessments considered, along with some reflection on its value. The course offers benefits to students by widening their perspective on anatomical knowledge and making them more equipped for the job market. It also broadens their understanding of form-function relationships. However, student feedback implied that having the choice between human or veterinary dissection was preferable, and this may outweigh the perceived benefits of the course.
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Anatomía , Educación de Pregrado en Medicina , Estudiantes de Medicina , Masculino , Humanos , Perros , Animales , Caballos , Ratones , Ovinos , Anatomía/educación , Anatomía Comparada/educación , Universidades , Curriculum , Disección/educación , Educación de Pregrado en Medicina/métodos , CadáverRESUMEN
PURPOSE: The aim of this qualitative study was to explore the views of participants of a group-based, supervised, telerehabilitation programme, following discharge from hospital with Covid-19. This study was part of a single-centre, fast-track (wait-list), randomised, mixed-methods, feasibility trial of telerehabilitation (Registration: Clinicaltrials.gov reference:285205). METHODS: Semi-structured interviews were conducted over a virtual teleconference platform with 10 participants who took part in a telerehabilitation programme following Covid-19 after discharge from an acute hospital. Data were transcribed verbatim and analysed using thematic analysis. RESULTS: Five themes were important from the participant perspective: telerehabilitation programme as part of the Covid-19 journey; the telerehabilitation programme design and delivery; peer aspects; the role of the instructor; and the role of technology and online delivery. CONCLUSIONS: Overall, the telerehabilitation programme was a positive experience for participants. The instructors were central to this positive view as was the group nature of the programme. The group aspect was particularly important in supporting the broader perceived wellbeing gains, such as the sense of enjoyment and reduced social isolation. Several participants would have liked to have continued with the exercises beyond the six-week intervention indicating that the programme could be a way to help people sustain a physically active lifestyle.IMPLICATIONS FOR REHABILITATIONParticipants who were recovering from Covid-19 following hospital admission perceived the telerehabilitation to be a positive experience overall.The group aspect of the telerehabilitation programme was important in supporting the broader perceived wellbeing gains such as the sense of enjoyment and reduced social isolation.Telerehabilitation programmes for Covid-19 may need to include pathways for participants to continue to engage in exercise beyond the time-limited six-week intervention to support ongoing self-management.
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COVID-19 , Telerrehabilitación , Humanos , Telerrehabilitación/métodos , COVID-19/epidemiología , Terapia por Ejercicio , Investigación Cualitativa , Ejercicio FísicoRESUMEN
Introduction: Coronavirus disease 2019 (COVID-19) has caused worldwide mass hospitalisation. The need for multidisciplinary post-hospitalisation rehabilitation is becoming increasingly apparent, and telerehabilitation has been endorsed. The aim of study was to investigate the feasibility and efficacy of pulmonary telerehabilitation for COVID-19 survivors. Methods: This was a single-centre, mixed-methods, fast-track (wait-list), randomised controlled trial of telerehabilitation for patients who had been hospitalised with COVID-19. 40 patients discharged from two university teaching hospitals in the north of England were recruited. Telerehabilitation consisted of 12 exercise classes, six education events and opportunity for peer support. Patients commenced telerehabilitation 14â days after randomisation in the fast-track group and 56â days after randomisation in the wait-list group. Outcome measures and results: Descriptive and statistical improvements were noted in several clinical outcome measures. Exercise capacity increased from a median (interquartile range) 20 (14-24) sit-to-stand repetitions in 1â min at baseline to 25 (24-30) post-telerehabilitation. Breathlessness rated using the Medical Research Council dyspnoea scale changed from 3.5 (3-4) at baseline to 2 (1.5-3) post-telerehabilitation, with additional favourable outcomes noted in respiratory symptoms measured using numerical rating scales and visual analogue scales (VAS). Quality of life measured using the EuroQol VAS improved from 55 (60-70) units at baseline to 70 (55-80) units following telerehabilitation. Improvements in fatigue (modified Functional Assessment of Chronic Illness Therapy: Fatigue) and mood (Hospital Anxiety and Depression Scale - Depression) were also observed. Natural recovery was observed in the wait-list group prior to receiving telerehabilitation; however, improvements were accelerated by early telerehabilitation in the fast-track group. Conclusions: We have shown that group-based telerehabilitation is feasible, safe, beneficial and well-received in this population.