The Potential effect of Low Cell Osmolarity on Cell Function through decreased concentration of enzyme substrates

© The Author(s) 2018. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. Some freshwater algae have lower (180 osmol m −3 ). Low osmolarities are related to the presence of flagella and the low energy cost of active water efflux following downhill water influx unconstrained by cell walls covering the plasmalemma, and the low resource cost of cell wall synthesis with the same mechanical degree of safety. One consequence of low intracellular osmolarity is limitation on the concentration of metabolites, that is, substrates and products of enzyme activity. Models of the flux through metabolic pathways, and hence the specific growth rate, using steady-state concentrations of enzymes and metabolites have involved organisms with intracellular metabolite osmolarities >280 osmol m −3 , where the metabolite concentrations are much greater than the total osmolarity of some freshwater algae. Since the protein concentration (mol m −3 ) in the cells and the specific growth rates of freshwater cells with low and with higher intracellular osmolarity are highly similar, the models of trade-offs between enzyme and metabolite concentrations for cells with high intracellular osmolarity need modification for cells with low intracellular osmolarity. The soluble free-radical scavenger ascorbate can constitute as little as 0.2% of the low intracellular metabolite concentration (mol m −3 ) of low-intracellular-osmolarity cells

What is the limit for photoautotrophic plankton growth rates?

© 2016 The Author. Knowing the potential maximum photoautotrophic growth rate for planktonic primary producers is fundamental to our understanding of trophic and biogeochemical processes, and of importance in applied phycology. When dayintegrated C-specific growth is considered over natural light:dark cycles, plausible RuBisCO activity (Kcat coupled with cellular RuBisCO content) caps growth to less than a few doubling per day. Prolonged periods of C-specific growth rates above ca. 1.3 d thus appear increasingly implausible. Discrepancies between RuBisCO-capped rates and reported microalgal-specific growth rates, including temperature-growth rate relationships, may be explained by transformational errors in growth rate determinations made by reference to cell counts or most often chlorophyll, or by extrapolations from short-Term measurements. Coupled studies of enzyme activity and day-on-day C-specific growth rates are required to provide definitive evidence of high growth rates. It seems likely, however, that selective pressure to evolve a RuBisCO with a high Kcat (with a likely concomitant increase in Km for CO2) would be low, as other factors such as light limitation (developing during biomass growth due to self-shading), nutrient limitations, CO2 depletion and pH elevation, would all rapidly depress realized specific growth rates

Nature reserves of the shires of York and Northam : summary of public submissions, May 1987

This document summarises and discusses submissions to the draft management plan (DMP) for nature reserves of the Shires of York and Northam. The submissions have been considered and detailed in this document according to the part of the plan to which they refer. The associated discussion and proposed changes to the draft are similarly structured. For the sake of brevity, every detail has not been included. For the above reasons this document should be read in conjunction with the amended plan. Further data on the flora of the York-Northam nature reserves have been collected over the period the DMP was available for comment. These data have been included in the final plan

The feasibility of psychomotor therapy in acute mental health services for adults with intellectual disability

Background. Psychomotor therapy enables people to reflect on the relationship between experiences and feelings by starting from awareness of bodily responses rather than from awareness of emotion. In this study we examine PsyMot (ID), an assessment that directs this psychological therapy. Method. Twelve suitable consecutive admissions were recruited from a specialist intellectual disability (ID) assessment and treatment unit for adults. Video-recordings of PsyMot (ID) allowed assessment of interrater reliability (IRR). Treatment goals indicated by PsyMot (ID) were addressed using psychomotor therapy as part of a comprehensive program of interventions. Results. Psychomotor therapy was both feasible and popular with patients who participated without any adverse effects. Nine patients completed PsyMot (ID). IRR of the treatment goals identified by all 3 raters was good to excellent in 81% cases, but there were discrepancies for individual items. Conclusions. PsyMot (ID) and psychomotor therapy is feasible within this context, and enriched the clinical team's formulation. Further studies of reliability and efficacy should be undertaken