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Background The clinical manifestation of COVID-19 is associated with infection and inflammation of the lungs, but there is evidence to suggest that COVID-19 may also affect the structure and function of the cardiovascular system. At present, it is not fully understood to what extent COVID-19 impacts cardiovascular function in the short- and long-term following infection. The aim of the present study is twofold: (i) to define the effect of COVID-19 on cardiovascular function (i.e. arterial stiffness, cardiac systolic and diastolic function) in otherwise healthy individuals and (ii) to evaluate the effect of a home-based physical activity intervention on cardiovascular function in people with a history of COVID-19. Methods This prospective, single-centre, observational study will recruit 120 COVID-19-vaccinated adult participants aged between 50 and 85 years, i.e. 80 with a history of COVID-19 and 40 healthy controls without a history of COVID-19. All participants will undergo baseline assessments including 12-lead electrocardiography, heart rate variability, arterial stiffness, rest and stress echocardiography with speckle tracking imaging, spirometry, maximal cardiopulmonary exercise testing, 7-day physical activity and sleep measures and quality of life questionnaires. Blood samples will be collected to assess the microRNA expression profiles, cardiac and inflammatory biomarkers, i.e. cardiac troponin T; N-terminal pro B-type natriuretic peptide; tumour necrosis factor alpha; interleukins 1, 6 and 10; C-reactive protein; d-dimer; and vascular endothelial growth factors. Following baseline assessments, COVID-19 participants will be randomised 1:1 into a 12-week home-based physical activity intervention aiming to increase their daily number of steps by 2000 from baseline. The primary outcome is change in left ventricular global longitudinal strain. Secondary outcomes are arterial stiffness, systolic and diastolic function of the heart, functional capacity, lung function, sleep measures, quality of life and well-being (depression, anxiety, stress and sleep efficiency). Discussion The study will provide insights into the cardiovascular implications of COVID-19 and their malleability with a home-based physical activity intervention. Trial registration ClinicalTrials.gov NCT05492552. Registered on 7 April 2022.

The effects of sleep deprivation on physical performance are well documented, but data on the consequence of sleep deprivation on recovery from exercise are limited. The aim was to compare cyclists' recovery from a single bout of high-intensity interval training (HIIT) after which they were given either a normal night of sleep (CON, 7.56 ± 0.63 h) or half of their usual time in bed (DEP, 3.83 ± 0.33 h).In this randomized cross-over intervention study, 16 trained male cyclists (age 32 ± 7 years), relative peak power output (PPO 4.6 ± 0.7 W kgPPO was reduced more 24 h after the HIIT session in the DEP (ΔPPO -0.22 ± 0.22 W kgOne night of partial sleep deprivation impairs recovery from a single HIIT session in cyclists. Further research is needed to understand the mechanisms behind this observation.

The Protea hybrid ‘Carnival’ (Protea compacta × Protea neriifolia) is responsive to seasonal change, arresting growth during the winter and producing flowers in the late summer after initiating flowering during the elongation of the spring flush. The large commercially attractive flower heads, consisting of over 200 florets, develop over a period of months. To begin to better understand the molecular factors that influence the transition to flowering in Protea, a homologue of the FLOWERING LOCUS T (FT) gene, ProFT, was isolated from ‘Carnival’, and its expression was analysed. ProFT showed increased expression in ‘Carnival’ leaves during October (13 h light/11 h dark; average daily temperature of 17 °C) at the time that floral organs were being pre-formed in the meristem. ProFT expression was fivefold higher in florally determined buds compared to that in leaves, and low levels were present in the vegetative meristems analysed. These results suggest that ProFT may act as a seasonally regulated floral inducer in ‘Carnival’, but based on spatial expression, data is also likely to play a role in inflorescence development and growth architecture.

Xerophyta humilis is a monocotyledonous resurrection plant found in arid and semi-arid summer rainfall areas of Southern Africa, which undergoes desiccation to survive periods of extreme drought. In order for X.humilis to thrive in their natural habitat, correct timing of the floral transition, coincident with wet periods of sufficient duration, is essential. In this study, the environmental cues involved in the regulation of the floral transition in X.humilis were analysed. No single parameter tested was sufficient to induce flowering, but it was found that flowering was promoted by a combination of a cool period experienced while plants were hydrated, followed by transfer to long-day photoperiods of relatively high light intensity. Plants retained competence to flower if desiccated during exposure to cold, but no flowering occurred if dried prior to this exposure. These data suggest that exposure to cold temperature facilitates vernalisation and subsequent exposure to high light and long days are inductive for floral initiation in X. humilis.

The Mesembryanthemoideae and Ruschioideae subfamilies are a major component of the Greater Cape Floristic Region in southern Africa. The Ruschioideae show an astonishing diversity of leaf shape and growth forms. Although 1,585 species are recognised within the morphologically diverse Ruschioideae, these species show minimal variation in plastid DNA sequence. We have investigated whether changes in selected leaf development transcription factors underpin the recent, rapid diversification of this large group of succulent plants. Degenerate primers designed to conserved regions of Asymmetric Leaves1/Rough Sheath 2/Phantastica (ARP) and the Class III HD-ZIP family of genes, were used to amplify sequences corresponding to these genes from several species within the Mesembryanthemoideae and Ruschioideae subfamilies. Two members of the Class III HD-ZIP family were identified in both the Mesembryanthemoideae and Ruschioideae, and were derived from an ancient gene duplication event that preceded the divergence of gymnosperms and angiosperms. While a single ARP orthologue was identified in the Mesembryanthemoideae, two paralogues, ARPa and ARPb, were identified in the Ruschioideae subfamily. ARPa was present in all species of Ruschioideae analysed in this study. ARPb has been lost from the Apatesieae and Dorotheantheae tribes, which form an early evolutionary branch from the Ruschieae tribe, as well as from selected species within the Ruschieae. The recent duplication and subsequent selected gene loss of the ARP transcription factor correlates with the rapid diversification of plant forms in the Ruschioideae.