Activities of H2O2-Converting Enzymes in Apple Leaf Buds during Dormancy Release in Consideration of the Ratio Change between Bud Scales and Physiologically Active Tissues

Hydrogen peroxide-converting enzyme activities in leaf buds of the apple cultivar Idared during the transition from dormancy release to the ontogenetic development were investigated. For this purpose, leaf buds were collected from 26 March 2021 (DOY = day of the year 85) to 23 April 2021 (DOY 113) and the air temperature was continuously monitored. Enzyme assay protocols for catalase (CAT), intracellular peroxidase (POX), and cell wall-bound peroxidase (cwPOX) in apple leaf buds were successfully established based on published protocols. All enzymes showed considerable changes in activity during the observation period. Fluctuation in daily mean air temperatures seemed not to affect the activities of POX and CAT, whereas severe drops in daily mean air temperature may have interrupted the assumed trajectory of cwPOX activity during the stage of ontogenetic development. In addition, the importance of considering changes in the ratio between physiologically active tissues and bud scales when investigating physiological changes in buds during the phase of dormancy release and ontogenetic development is discussed. A new reference system, namely the “adjusted dry weight” [aDW], is proposed to circumvent this shift in ratios when working with scaled buds

Activities of H₂O₂-Converting Enzymes in Apple Leaf Buds during Dormancy Release in Consideration of the Ratio Change between Bud Scales and Physiologically Active Tissues

Hydrogen peroxide-converting enzyme activities in leaf buds of the apple cultivar Idared during the transition from dormancy release to the ontogenetic development were investigated. For this purpose, leaf buds were collected from 26 March 2021 (DOY = day of the year 85) to 23 April 2021 (DOY 113) and the air temperature was continuously monitored. Enzyme assay protocols for catalase (CAT), intracellular peroxidase (POX), and cell wall-bound peroxidase (cwPOX) in apple leaf buds were successfully established based on published protocols. All enzymes showed considerable changes in activity during the observation period. Fluctuation in daily mean air temperatures seemed not to affect the activities of POX and CAT, whereas severe drops in daily mean air temperature may have interrupted the assumed trajectory of cwPOX activity during the stage of ontogenetic development. In addition, the importance of considering changes in the ratio between physiologically active tissues and bud scales when investigating physiological changes in buds during the phase of dormancy release and ontogenetic development is discussed. A new reference system, namely the “adjusted dry weight” [aDW], is proposed to circumvent this shift in ratios when working with scaled buds

Simple and robust determination of the activity signatureof key carbohydrate metabolism enzymes for physiologicalphenotyping in model and crop plants

The analysis of physiological parameters is important to understand the link between plant phenotypes and their genetic bases, and therefore is needed as an important element in the analysis of model and crop plants. The activities of enzymes involved in primary carbohydrate metabolism have been shown to be strongly associated with growth performance, crop yield, and quality, as well as stress responses. A simple, fast, and cost-effective method to determine activities for 13 key enzymes involved in carbohydrate metabolism has been established, mainly based on coupled spectrophotometric kinetic assays. The comparison of extraction buffers and requirement for dialysis of crude protein extracts resulted in a universal protein extraction protocol, suitable for the preparation of protein extracts from different organs of various species. Individual published kinetic activity assays were optimized and adapted for a semi-high-throughput 96-well assay format. These assays proved to be robust and are thus suitable for physiological phenotyping, enabling the characterization and diagnosis of the physiological state. The potential of the determination of distinct enzyme activity signatures as part of a physiological fingerprint was shown for various organs and tissues from three monocot and five dicot model and crop species, including two case studies with external stimuli. Differential and specific enzyme activity signatures are apparent during inflorescence development and upon in vitro cold treatment of young inflorescences in the monocot ryegrass, related to conditions for doubled haploid formation. Likewise, treatment of dicot spring oilseed rape with elevated CO2 concentration resulted in distinct patterns of enzyme activity responses in leaves.(VLID)310311

The scope of flavin-dependent reactions and processes in the model plant Arabidopsis thaliana

Eggers, Reinmar, Jammer, Alexandra, Jha, Shalinee, Kerschbaumer, Bianca, Lahham, Majd, Strandback, Emilia, Toplak, Marina, Wallner, Silvia, Winkler, Andreas, Macheroux, Peter (2021): The scope of flavin-dependent reactions and processes in the model plant Arabidopsis thaliana. Phytochemistry (112822) 189: 1-42, DOI: 10.1016/j.phytochem.2021.112822, URL: http://dx.doi.org/10.1016/j.phytochem.2021.11282

Postoperative continuous positive airway pressure to prevent pneumonia, re-intubation, and death after major abdominal surgery (PRISM): a multicentre, open-label, randomised, phase 3 trial

Background: Respiratory complications are an important cause of postoperative morbidity. We aimed to investigate whether continuous positive airway pressure (CPAP) administered immediately after major abdominal surgery could prevent postoperative morbidity. Methods: PRISM was an open-label, randomised, phase 3 trial done at 70 hospitals across six countries. Patients aged 50 years or older who were undergoing elective major open abdominal surgery were randomly assigned (1:1) to receive CPAP within 4 h of the end of surgery or usual postoperative care. Patients were randomly assigned using a computer-generated minimisation algorithm with inbuilt concealment. The primary outcome was a composite of pneumonia, endotracheal re-intubation, or death within 30 days after randomisation, assessed in the intention-to-treat population. Safety was assessed in all patients who received CPAP. The trial is registered with the ISRCTN registry, ISRCTN56012545. Findings: Between Feb 8, 2016, and Nov 11, 2019, 4806 patients were randomly assigned (2405 to the CPAP group and 2401 to the usual care group), of whom 4793 were included in the primary analysis (2396 in the CPAP group and 2397 in the usual care group). 195 (8\ub71%) of 2396 patients in the CPAP group and 197 (8\ub72%) of 2397 patients in the usual care group met the composite primary outcome (adjusted odds ratio 1\ub701 [95% CI 0\ub781-1\ub724]; p=0\ub795). 200 (8\ub79%) of 2241 patients in the CPAP group had adverse events. The most common adverse events were claustrophobia (78 [3\ub75%] of 2241 patients), oronasal dryness (43 [1\ub79%]), excessive air leak (36 [1\ub76%]), vomiting (26 [1\ub72%]), and pain (24 [1\ub71%]). There were two serious adverse events: one patient had significant hearing loss and one patient had obstruction of their venous catheter caused by a CPAP hood, which resulted in transient haemodynamic instability. Interpretation: In this large clinical effectiveness trial, CPAP did not reduce the incidence of pneumonia, endotracheal re-intubation, or death after major abdominal surgery. Although CPAP has an important role in the treatment of respiratory failure after surgery, routine use of prophylactic post-operative CPAP is not recommended