Consolidated bioprocessing of corn cob-derived hemicellulose: engineered industrial Saccharomyces cerevisiae as efficient whole cell biocatalysts

Background Consolidated bioprocessing, which combines saccharolytic and fermentative abilities in a single microorganism, is receiving increased attention to decrease environmental and economic costs in lignocellulosic biorefineries. Nevertheless, the economic viability of lignocellulosic ethanol is also dependent of an efficient utilization of the hemicellulosic fraction, which contains xylose as a major component in concentrations that can reach up to 40% of the total biomass in hardwoods and agricultural residues. This major bottleneck is mainly due to the necessity of chemical/enzymatic treatments to hydrolyze hemicellulose into fermentable sugars and to the fact that xylose is not readily consumed by Saccharomyces cerevisiaethe most used organism for large-scale ethanol production. In this work, industrial S. cerevisiae strains, presenting robust traits such as thermotolerance and improved resistance to inhibitors, were evaluated as hosts for the cell-surface display of hemicellulolytic enzymes and optimized xylose assimilation, aiming at the development of whole-cell biocatalysts for consolidated bioprocessing of corn cob-derived hemicellulose. Results These modifications allowed the direct production of ethanol from non-detoxified hemicellulosic liquor obtained by hydrothermal pretreatment of corn cob, reaching an ethanol titer of 11.1 g/L corresponding to a yield of 0.328 g/g of potential xylose and glucose, without the need for external hydrolytic catalysts. Also, consolidated bioprocessing of pretreated corn cob was found to be more efficient for hemicellulosic ethanol production than simultaneous saccharification and fermentation with addition of commercial hemicellulases. Conclusions These results show the potential of industrial S. cerevisiae strains for the design of whole-cell biocatalysts and paves the way for the development of more efficient consolidated bioprocesses for lignocellulosic biomass valorization, further decreasing environmental and economic costs.This work has been carried out at the Biomass and Bioenergy Research Infrastructure (BBRI)-LISBOA-01-0145-FEDER-022059, supported by Operational Programme for Competitiveness and Internationalization (PORTUGAL2020), by Lisbon Portugal Regional Operational Programme (Lisboa 2020) and by North Portugal Regional Operational Programme (Norte 2020) under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF) and has been supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020, the “Contrato-Programa” UIDB/04050/2020, the MIT-Portugal Program (Ph.D. Grant PD/BD/128247/2016 to Joana T. Cunha) and through Project FatVal (POCI-01-0145-FEDER-032506) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Psychometric Properties of the 'Patients' Perspective of the Quality of Palliative Care Scale'

Objectives: Palliative care is a basic human right for all patients suffering from progressive and excruciating pain, limitations in daily activities as well as requiring constant care. The development of palliative care is always associated with the physical, psychological, social and spiritual care quality level and requires continuous evaluation by the care-receiving patients. This study aimed to determine the psychometric properties of the patients' perspective of the quality of palliative care scale. Materials and Methods: This methodological study was conducted on 500 patients with chronic diseases admitted to the hospitals affiliated in Golestan University of Medical Sciences, between 2019 and 2020. Participants were selected through stratified sampling through proportional allocation as well as considering the bed occupancy rate in the two referral hospitals of the university. According to Wild approach, we translated the original version of the scale the patients' perspectives of the quality of the palliative care scale with 35 items and eight subscales. Using exploratory and confirmatory factor analysis, the psychometric properties of the scale (i.e., initial reliability and face, content, convergent and construct validities) were assessed. The reliability of the scale was calculated by applying Cronbach's alpha coefficient, McDonald's omega coefficient and the Intraclass correlation coefficient (ICC). SPSS- 16 and AMOS-24 software programs were used to analyse the data. Results: Three items were omitted after assessing the initial reliability of the translated version of the perspectives of the quality of the palliative care scale using adjusted Cronbach's alpha. The qualitative face validity and impact score of the remaining items of the scale were confirmed by the target group. Meanwhile, a panel of experts confirmed the content validity ratio and content validity index. Convergent validity was approved by calculating the average variance extracted >0.5. Performing EFA led to the extraction of 7 subscales with 32 items. CFA and goodness of fit indices such as GFI = 0.98, CFI = 0.91, RMSEA = 0.048 and GFI = 0.97 confirmed the construct model by omitting three items. Hence, the Persian version of the patient's perspective of the quality of palliative care scale was finalised, including seven subscales with 29 items. ICC of >0.7 represented good reliability. Moreover, Cronbach's alpha and McDonald's omega coefficient confirmed the internal consistency of the scale. Conclusion: Based on the findings of this study, the Persian version of the patients' perspective of the quality of palliative care scale is introduced as a valid and reliable scale. It can accurately indicate and predict the meticulous quality of such care in hospitalised patients and can be used in the cure and care assessments in the health system. © 2022 Wolters Kluwer Medknow Publications. All rights reserved

A Role For Wind-Up in Trigeminal Sensory Processing: Intensity Coding of Nociceptive Stimuli in the Rat

Wind-up is a progressive, frequency-dependent increase in the excitability of trigeminal and spinal dorsal horn wide dynamic range (WDR) nociceptive neurons evoked by repetitive stimulation of primary afferent nociceptive C-fibres. The correlate of wind-up in humans is temporal summation, which is an increase in pain perception to repetitive constant nociceptive stimulation. Although wind-up is widely used as a tool for studying the processing of nociceptive information, including central sensitization, its actual role is still unknown. Here, we recorded from trigeminal WDR neurons using in vivo electrophysiological techniques in rats and assessed the wind-up phenomenon in response to stimuli of different intensities and frequencies. First, we found that the amplitude of C-evoked responses of WDR neurons to repetitive stimulation increased progressively to reach a peak, then consistently showed a stable or slightly decreasing plateau phase. Only the first phase of this time course fitted in with the wind-up description. Therefore, to assess wind-up, we measured a limited number of initial responses. Second, we showed that wind-up, i.e. the slope of the frequency-dependent increase in the response to C-fibre stimulation, was linearly correlated to the stimulus intensity. Intensities of brief C-fibre inputs were thus coded into frequencies of action potentials by second-order neurons through frequency-dependent potentiation of the evoked responses. Third, wind-up also occurred at stimulation intensities below the threshold for C-evoked responses in WDR neurons, suggesting that wind-up can amplify subthreshold C-fibre inputs to WDR neurons. This might account for the observation that sparse, subliminal, neuronal activity in nociceptors can become painful via central integration of neural responses. Altogether, the present results show that wind-up can provide trigeminal WDR neurons with the capability to encode the intensity of short-duration orofacial nociceptive stimuli and to detect subthreshold nociceptive input. Thus, not only may wind-up play a physiological role in trigeminal sensory processing, but its enhancement may also underlie the pathophysiology of chronic orofacial pain conditions