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Highlights: [•] Comprehensive review of neuroprotective gases for multiple neural diseases. [•] Summary of underlying mechanisms for their neuroprotective effects. [•] Possible limitations hindering clinical translation of neuroprotective gases. [ABSTRACT FROM AUTHOR]

Abstract: The present study examines how different pCO2 acclimations affect the CO2- and light-dependence of photophysiological processes and O2 fluxes in four Southern Ocean (SO) key phytoplankton species. We grew Chaetoceros debilis (Cleve), Pseudo-nitzschia subcurvata (Hasle), Fragilariopsis kerguelensis (O'Meara) and Phaeocystis antarctica (Karsten) under low (160μatm) and high (1000μatm) pCO2. The CO2- and light-dependence of fluorescence parameters of photosystem II (PSII) were determined by means of a fluorescence induction relaxation system (FIRe). In all tested species, nonphotochemical quenching (NPQ) is the primary photoprotection strategy in response to short-term exposure to high light or low CO2 concentrations. In C. debilis and P. subcurvata, PSII connectivity (p) and functional absorption cross-sections of PSII in ambient light (σPSII′) also contributed to photoprotection while changes in re-oxidation times of Qa acceptor (τQa) were more significant in F. kerguelensis. The latter was also the only species being responsive to high acclimation pCO2, as these cells had enhanced relative electron transport rates (rETRs) and σPSII′ while τQa and p were reduced under short-term exposure to high irradiance. Low CO2-acclimated cells of F. kerguelensis and all pCO2 acclimations of C. debilis and P. subcurvata showed dynamic photoinhibition with increasing irradiance. To test for the role and presence of the Mehler reaction in C. debilis and P. subcurvata, the light-dependence of O2 fluxes was estimated using membrane inlet mass spectrometry (MIMS). Our results show that the Mehler reaction is absent in both species under the tested conditions. We also observed that dark respiration was strongly reduced under high pCO2 in C. debilis while it remained unaltered in P. subcurvata. Our study revealed species-specific differences in the photophysiological responses to pCO2, both on the acclimation as well as the short-term level. [Copyright &y& Elsevier]

Abstract: Mitochondrial DNA damage has been used as a successful and unique biomarker of tissue stress. A valuable example of this is sun damage in human skin which leads to ageing and skin cancer. The skin is constantly exposed to the harmful effects of sunlight, such as ultraviolet radiation, which causes it to age with observable characteristic features as well as clinical precancerous lesions and skin cancer. Formation of free radicals by the sun's harmful rays which contribute to oxidative stress has been linked to the induction of deletions and mutations in the mitochondrial DNA. These markers of mitochondrial DNA damage have been proposed to contribute to the mechanisms of ageing in many tissues including skin and are associated with many diseases including cancer. In this article we highlight the role of this important organelle in ageing and cancer with particular emphasis on experimental strategies in the skin. [Copyright &y& Elsevier]

Abstract: A metabolic model for cell growth and recombinant protein overproduction in Escherichia coli, which includes expression vector properties such as plasmid copy number and promoter strength as input parameters, was developed. Linear programming was used to obtain pathway fluxes for selected systems. The experimentally observed slow growth of recombinant E. coli XL1 in minimal medium supplemented with glucose accompanied with significant acetic acid secretion was successfully simulated by metabolic flux analysis (MFA) computations. The expression of the fusion protein GI-malE induced by IPTG caused a severe retardation in cell growth rate from μ=0.066 to 0.006h-1 and increased acetic acid secretion to the medium. The metabolic flux analysis of this transition in growth condition show that cells shift the usage of the available substrate from anabolic to catabolic pathways to increase their ability to produce energy for plasmid-encoded protein synthesis, stress protein synthesis and maintenance requirements. The increase in catabolic fluxes led to increased acetic acid secretion rate. MFA analysis of EcoRI endonuclease expression in E. coli 294 at high growth rate and accompanied by low growth rate depression showed that the flux distribution was very similar for both host and induced cells. The pathway utilization simulate exponential growth condition with preference for the PP pathway and activation of the glyoxalate shunt to meet the high demand for NADPH, NADH and biosynthetic intermediates at high growth rate. For both of the systems studied the pathway utilization and relative flux distributions obtained from MFA are in good agreement with reported E. coli gene expression profiles at different stages of growth and during recombinant protein overexpression. [Copyright &y& Elsevier]