Liver mitochondrial and whole-animal level metabolic compensation in a catfish during seasonal acclimatization

To examine whether metabolic compensation during seasonal acclimatization at the liver mitochondrial level is consistent with that at the whole-animal level, respiration rates of liver mitochondria and resting metabolic rates in winter- and sum- meracclimatized southern catfish （Silurus meridionalis Chen） were measured. At 12.5, 17.5, 22.5, 27.5 and 32.5~C, the mean values of state 3 respiration rates were 12.21, 13.84, 18.96, 24.78 and 32.01 nmol O2min-1 mg-1 mitochondrial protein in the winter group, and 8.56, 9.20, 17.32, 22.74 and 26.32 nmol 02 min-1 mgq in the summer group, respectively. At the five assay temperatures the resting metabolic rates were 24.86, 42.68, 61.59, 84.10 and 125.65 mg 02 h-1 kgI body mass in the winter group, and 22.89, 40.59, 52.94, 75.13 and 109.35 mg Oz h-1 kg-1 in the summer group, respectively. Total mitochondrial respiration rates in the liver organ were estimated based on state 3 respiration rates, mitochondrial protein content and organ mass, and the mean values were 72.96, 71.87, 112.47, 167.35 and 183.27 nmol Ozmin-lin the winter group, and were 47.89, 47.39, 105.67, 138.18 and 132.29 nmol 02 min-1 in the summer group, respectively. Metabolic compensation caused by seasonal acclimatization occurred at the liver mitochondrial level and compensation at the liver organ level was found to be more efficient because of an in- crease in metabolic capacity of mitochondria and a boost in organ mass. Metabolic compensation at the whole-animal level was not detected. During seasonal acclimatization, the effect of metabolic compensation at liver mitochondrial level is inconsistent with that at the whole-animal level in the southern catfish. This may be due to different degrees of regulation of metabolic mechanisms among various tissues and organs in an acclimatized organism

An analysis of the mechanism underlying photocatalytic disinfection based on integrated metabolic networks and transcriptional data

Photocatalytic disinfection has long been used to combat pathogenic bacteria.However,the specific mechanism underlying photocatalytic disinfection and its corresponding targets remain unclear.In this study,an analysis of the potential mechanism underlying photocatalytic disinfection was performed based on integrated metabolic networks and transcriptional data.Two sets of RNA-seq data(wild type and a photocatalysis-resistant mutant mediated by titanium dioxide(TiO2))were processed to constrain the genome scale metabolic models(GSMM)of E.coli.By analyzing the metabolic network,the differential metabolic flux of every reaction was computed in constrained GSMM,and several significantly differential metabolic fluxes in reactions were extracted and analyzed.Most of these reactions were involved in the transmembrane transport of substances and occurred on the inner membrane or were an important component of the cell membrane.These results,which are consistent with the reported information,validated our analysis process.In addition,our work also identified other new and valuable metabolic pathways,such as the reaction ALCD2x,which has a great effect on the energy production process under bacterial anaerobic conditions.The DHAK reaction is also related to the metabolic process of ATP.These reactions with large differential metabolic fluxes merit further research.Additionally,to provide a strategy to address photocatalysis-resistant mutant bacteria,a metabolic compensation analysis was also performed.The metabolic compensation analysis results provided suggestions for a combined method that can effectively combat resistant bacteria.This method could also be used to explore the mechanisms of drug resistance in other microorganisms.