This study investigates the effect of short-and long-term changes in temperature on the regulation of root respiratory O 2 uptake by substrate supply, adenylate restriction and/or the capacity of the respiratory system. The species investigated were the lowland Plantago lanceolata L. and alpine Plantago euryphylla Briggs , Carolin & Pulley, which are inherently fast-and slow-growing, respectively. The plants were grown hydroponically in a controlled environment (constant 23 ∞ ∞ ∞ ∞ C). The effect of long-term exposure to low temperature on regulation of respiration was also assessed in P. lanceolata using plants transferred to 15/ 10 ∞ ∞ ∞ ∞ C (day/night) for 7 d. Exogenous glucose and uncoupler (CCCP) were used to assess the extent to which respiration rates were limited by substrate supply and adenylates. The results suggest that adenylates and/or substrate supply exert the greatest control over respiration at moderate temperatures (e.g. 15-30 ∞ ∞ ∞ ∞ C) in both species. At low temperatures (5-15 ∞ ∞ ∞ ∞ C), CCCP and glucose had little effect on respiration, suggesting that respiration was limited by enzyme capacity alone. The Q 10 (proportional increase of respiration per 10 ∞ ∞ ∞ ∞ C) of respiration was increased following the addition of CCCP and/or exogenous glucose. The degree of stimulation by CCCP was considerably lower in P. euryphylla than P. lanceolata . This suggests that respiration rates operate much closer to the maximum capacity in P. euryphylla than P. lanceolata . When P. lanceolata was transferred to 15 ∞ ∞ ∞ ∞ C for 7 d, respiration acclimated to the lower growth temperature (as demonstrated by an increase in respiration rates measured at 25 ∞ ∞ ∞ ∞ C). In addition, the Q 10 was higher, and the stimulatory effect of exogenous glucose and CCCP lower, in the cold-acclimated roots in comparison with their warm-grown counterparts. Acclimation of P. lanceolata to different day/night-time temperature regimes was also investigated. The low nighttime temperature was found to be the most important factor influencing acclimation. The Q 10 values were also higher in plants exposed to the lowest night-time temperature. The results demonstrate that short-and long-term changes in temperature alter the importance of substrate supply, adenylates and capacity of respiratory enzymes in regulating respiratory flux.

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The ICH M7 guidance provides a series of flexible control options for the control of (potentially) mutagenic impurities (PMIs) that fully align with key risk-based principles. This includes option 4, which leverages existing process knowledge and/or data to justify control of PMIs without the need for routine analytical release testing during manufacturing. One such technique highlighted uses systematic, semiquantitative calculations to define the degree of "purge" of PMIs within a synthetic route to an active pharmaceutical ingredient (API) based on physicochemical properties of the impurities in question, and the manufacturing process being undertaken. This paper introduces a consortium-led initiative, Mirabilis, which aims to build on the semiquantitative purge approach, and harmonize industry best practices by enabling the calculations to be conducted in a standardized, consistent, and reproducible manner. The development of an expert-derived knowledge base for the prediction of reactivity by enhancing expert opinion using evidence derived from the published literature and experimental data is also discussed. Furthermore, this paper describes the application of Mirabilis software for the processes involved in the synthesis of verubecestat, naloxegol oxalate, and camicinal.

In many environments, leaves experience large diurnal variations in temperature. Such short-term changes in temperature are likely to have important implications for respiratory metabolism in leaves. Here, we used intact leaf, protoplasts and isolated mitochondria to determine the impact of short-term changes in temperature on respiration rates (R), adenylate concentrations and the redox poise of the ubiquinone (UQ) pool in mitochondria of potato leaves. The Q 10 (i.e. proportional change in R for each 10°C rise in temperature) of respiration was 1.8, both for intact leaves and protoplasts. In protoplasts, the redox poise of the extracted UQ pool (UQ R /UQ T ) increased from 0.33 at 22°C, to 0.76 at 15°C. Further decreases in temperature (from 15 to 5°C) resulted in UQ R / UQ T decreasing to 0.40. Adenylate ratios in protoplasts were also temperature dependent. At high adenosine 5#-triphosphate (ATP) adenosine 5#-diphosphate (ADP) ratios (i.e. low ADP concentrations), UQ R /UQ T values were low, suggesting that adenylates restricted flux via the UQ-reducing pathways more than they restricted flux via pathways that oxidized UQH 2 . To assess whether high rates of alternative oxidase (AOX) activity could have uncoupled respiratory flux (and thus UQ R /UQ T ) from adenylate restriction of the cytochrome (Cyt) pathway, we constructed kinetic curves of O 2 uptake (via the two pathways) vs UQ R /UQ T in isolated mitochondria, measured at two temperatures (15 and 25°C); measurements were made for mitochondria operating under state 3 (i.e. 1ADP) and state 4 (i.e. 2ADP) conditions. In contrast to the Cyt pathway, flux via the AOX was temperature insensitive, with maximal rates of AOX activity representing 21-57% of total O 2 uptake in isolated mitochondria. We conclude that temperature-dependent variations in UQ R /UQ T are largely dependent on temperature-dependent changes in adenylate ratios, and that flux via the AOX could in some circumstances help reduce maximal UQ values.