79 research outputs found

    Sugar sensing responses to low and high light in leaves of the C4 model grass Setaria viridis

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    Although sugar regulate photosynthesis, the signalling pathways underlying this process remain elusive, especially for C4 crops. To address this knowledge gap and identify potential candidate genes, we treated Setaria viridis (C4 model) plants acclimated to medium light intensity (ML, 500 µmol m-2 s-1) with low (LL, 50 µmol m-2 s-1) or high (HL, 1000 µmol m-2 s-1) light for 4 days and observed the consequences on carbon metabolism and the transcriptome of source leaves. LL impaired photosynthesis and reduced leaf content of signalling sugars (glucose, sucrose and trehalose-6-phosphate). Contrastingly, HL strongly induced sugar accumulation without repressing photosynthesis. LL more profoundly impacted leaf transcriptome, including photosynthetic genes. LL and HL contrastingly altered the expression of HXK and SnRK1 sugar sensors and trehalose pathway genes. The expression of key target genes of HXK and SnRK1 were affected by LL and sugar depletion, while surprisingly HL and strong sugar accumulation only slightly repressed the SnRK1 signalling pathway. In conclusion, we demonstrate that LL profoundly impacted photosynthesis and the transcriptome of S. viridis source leaves, while HL altered sugar levels more than LL. We also present the first evidence that sugar signalling pathways in C4 source leaves may respond to light intensity and sugar accumulation differently to C3 source leaves

    Sugar sensing responses to low and high light in leaves of the C4 model grass Setaria viridis

    Get PDF
    Although sugar regulate photosynthesis, the signalling pathways underlying this process remain elusive, especially for C4 crops. To address this knowledge gap and identify potential candidate genes, we treated Setaria viridis (C4 model) plants acclimated to medium light intensity (ML, 500 µmol m-2 s-1) with low (LL, 50 µmol m-2 s-1) or high (HL, 1000 µmol m-2 s-1) light for 4 days and observed the consequences on carbon metabolism and the transcriptome of source leaves. LL impaired photosynthesis and reduced leaf content of signalling sugars (glucose, sucrose and trehalose-6-phosphate). Contrastingly, HL strongly induced sugar accumulation without repressing photosynthesis. LL more profoundly impacted leaf transcriptome, including photosynthetic genes. LL and HL contrastingly altered the expression of HXK and SnRK1 sugar sensors and trehalose pathway genes. The expression of key target genes of HXK and SnRK1 were affected by LL and sugar depletion, while surprisingly HL and strong sugar accumulation only slightly repressed the SnRK1 signalling pathway. In conclusion, we demonstrate that LL profoundly impacted photosynthesis and the transcriptome of S. viridis source leaves, while HL altered sugar levels more than LL. We also present the first evidence that sugar signalling pathways in C4 source leaves may respond to light intensity and sugar accumulation differently to C3 source leave

    Walking with a rollator and the level of physical intensity in adults 75 years of age or older.

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    Eggermont LH, van Heuvelen MJ, van Keeken BL, Hollander AP, Scherder EJ. Walking with a rollator and the level of physical intensity in adults 75 years of age or older. Objective: To determine whether walking with a rollator by persons 75 years of age or older is of sufficient intensity to improve aerobic fitness. Design: A cross-sectional cohort study. Setting: University movement laboratory. Participants: Fifteen subjects 75 years of age or older (mean age, 83.7y) who could only walk by using a rollator. Interventions: Not applicable. Main Outcome Measures: During 6 minutes of self-paced treadmill walking using a rollator at a mean walking speed of 0.6m/s, oxygen uptake (V̇

    Osteo-cise: Strong Bones for Life: protocol for a community-based randomised controlled trial of a multi-modal exercise and osteoporosis education program for older adults at risk of falls and fractures

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    Background : Osteoporosis affects over 220 million people worldwide, and currently there is no \u27cure\u27 for the disease. Thus, there is a need to develop evidence-based, safe and acceptable prevention strategies at the population level that target multiple risk factors for fragility fractures to reduce the health and economic burden of the condition. Methods : The \u27Osteo-cise: Strong Bones for Life\u27 study will investigate the effectiveness and feasibility of a multi-component targeted exercise, osteoporosis education/awareness and behavioural change program for improving bone health and muscle function, and reducing falls risk in community-dwelling older adults at an increased risk of fracture. Men and women aged 60 years or above will participate in an 18-month randomised controlled trial comprising a 12-month structured and supervised community-based program and a 6-month \u27research to practise\u27 translational phase. Participants will be randomly assigned to either the \u27Osteo-cise\u27 intervention or a self-management control group. The intervention will comprise a multi-modal exercise program incorporating high velocity progressive resistance training, moderate impact weight-bearing exercise and high challenging balance exercises performed three times weekly at local community-based fitness centres. A behavioural change program will be used to enhance exercise adoption and adherence to the program. Community-based osteoporosis education seminars will be conducted to improve participant knowledge and understanding of the risk factors and preventative measures for osteoporosis, falls and fractures. The primary outcomes measures, to be collected at baseline, 6, 12, and 18 months, will include DXA-derived hip and spine bone mineral density measurements and functional muscle power (timed stair-climb test). Secondary outcomes measures include: MRI-assessed distal femur and proximal tibia trabecular bone micro-architecture, lower limb and back maximal muscle strength, balance and function (four square step test, functional reach test, timed up-and-go test and 30-second sit-to-stand), falls incidence and health-related quality of life. Cost-effectiveness will also be assessed. Discussion : The findings from the Osteo-cise: Strong Bones for Life study will provide new information on the efficacy of a targeted multi-modal community-based exercise program incorporating high velocity resistance training, together with an osteoporosis education and behavioural change program for improving multiple risk factors for falls and fracture in older adults at risk of fragility fracture.<br /

    Trikhomonadoz vo vremja poslerodovogo perioda

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    T. vaginalis was found in 21.8% out of 320 parturient women in the Clinic; in 91% of the pregnant infested with T. vaginalis there were inflammatory manifestations of the vagina during pregnancy. In the puerperium, the infested women often showed longstanding temperature rises. The reasons accounting for the febrile course of the puerperium in women infested with T. vaginalis are discussed

    Plant acclimation and adaptation to a high CO2 world

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    Plant adaptation to elevated atmospheric carbon dioxide (CO2) is of great interest, as the concentration of this gas in the atmosphere has risen by more than 30% to 388 µmol mol-1 since the industrial revolution. On average there has been a rise of 3 ppm per year. Plant fossil samples suggest that atmospheric CO2 may be acting as a selective agent driving evolution, but limited evidence is available to support this idea that plants subjected to future predicted concentrations of carbon dioxide may adapt. In contrast, much evidence is available on plant acclimation mechanisms and phenotypinc plasticity in future high CO2 concentrations. Studying evolutionary responses to this aspect of environmental change is difficult, but here we use a CO2 spring site where plants have been exposed for multiple generations to concentrations of CO2 predicted for 2050. From this, detailed phenotyping data were collected, including data for stomatal patterning, photosynthetic performance and growth. Considerable evidence exists to show that stomatal numbers have declined across geological time and that this is linked to CO2 concentration, but few CO2-sensitive stomatal patterning genes have ever been identified. When grown under elevated CO2 concentrations P. lanceolata (the narrow leaf plantain), seeds collected from the spring site showed a counter-intuitive increase in stomatal index and density. Here, in this non-model plant we have investigated the gene expression changes underlying this stomatal patterning response to elevated CO2.RNA-Seq allowed for in-depth analysis in P. lanceolata with no previous information required, enabling rapid evaluation of any of novel plant acclimation and adaption mechanisms. Using this approach we have identified a set of novel genes for stomatal patterning in high CO2 and confirmed previously observed acclimation responses
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