Determination Of Oxygen Consumption Research Articles

Metabolic energetic adaptation of Atlantic salmon phagocytes to changes in carbon sources and exposure to PAMPs

Phagocytic cells are pivotal for host homeostasis and infection defense, necessitating metabolic adaptations in glycolysis, the tricarboxylic acid (TCA) cycle, and oxidative phosphorylation (OXPHOS). While mammalian phagocytes shift towards glycolysis and glutaminolysis during polarization, research on fish phagocyte metabolic reprogramming is limited. To address this, the Atlantic salmon phagocytic cell line, SHK-1, serves as a valuable model. Using the Seahorse XFe96 Flux Analyzer, this study compares SHK-1 bioenergetics under glucose-restricted (L-15 medium) and glucose-supplemented (PM) conditions, providing insights into metabolic characteristics and responses to Piscirickettsia salmonis bacterium Pathogen-associated molecular patterns (PAMPs). A standardized protocol for the study of real-time changes in the metabolism study of SHK-1 in PM and L-15 media, determining oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) is shown. Exhibiting metabolic adaptations, SHK-1 cells in the PM medium have higher basal and maximal OCR and spare capacity (SRC), while those grown in the L-15 medium favor OXPHOS, showing minimal glycolytic function. Despite metabolic differences, intracellular ATP levels are comparable, highlighting the metabolic plasticity and adaptability of SHK-1 cells to various carbon sources. Exposure to PAMPs from Piscirickettsia salmonis induces a metabolic shift, increasing glycolysis and OXPHOS, influencing ATP, lactate, glutamine, and glutamate levels. These findings highlight the role of mitochondrial bioenergetics and metabolic plasticity in salmon phagocytes, offering novel nutritional strategies for host-pathogen interventions based on energy metabolism.

Mitochondrial dysfunction in platelets from severe trauma patients - A prospective case-control study

IntroductionTrauma-induced coagulopathy (TIC) refers to an abnormal coagulation process, an imbalance between coagulation and fibrinolysis due to several pathological factors, such as haemorrhage and tissue injury. Platelet activation and subsequent clot formation are associated with mitochondrial activity, suggesting a possible role for mitochondria in TIC. Comprehensive studies of mitochondrial dysfunction in platelets from severe trauma patients have not yet been performed. MethodsIn this prospective case-control study, patients with severe trauma (ISS≥16) had venous blood samples taken at arrival to the Emergency Unit of a Level 1 Trauma Centre. Mitochondrial functional measurements (Oxygraph-2k, Oroboros) were performed to determine oxygen consumption in different respiratory states, the H2O2 production and extramitochondrial Ca2+ movements. In addition, standard laboratory and coagulation tests, viscoelastometry (ClotPro) and aggregometry (Multiplate) were performed. Measurements data were compared with age and sex matched healthy control patients. ResultsSevere trauma patients (n = 113) with a median age of 38 years (IQR, 20–51), a median ISS of 28 (IQR, 20–48) met our inclusion criteria. Oxidative phosphorylation in platelet mitochondria from severe trauma patients significantly decreased compared to controls (34.7 ± 8.8 pmol/s/mL vs. 48.0 ± 19.7 pmol/s/mL). The mitochondrial H2O2 production significantly increased and greater endogenous Ca2+ release was found in the polytrauma group. Consistent with these results, clotting time (CT) increased while maximum clot firmness (MCF) decreased with the EX-test and FIB-test in severe trauma samples. Multiplate aggregometry showed significantly decreased ADP-test (38 ± 12 AUC vs. 112 ± 14 AUC) and ASPI test (78 ± 22 AUC vs. 84 ± 28 AUC) also tended to decrease in mitochondria of polytrauma patients as compared with controls. Significant strong correlation has been demonstrated between mitochondrial OxPhos and MCF while it was negatively correlated with ISS (R2=0.448, P˂0.05), INR, CT and lactate level of patients. ConclusionsThe present study revealed that severe trauma is associated with platelet mitochondrial dysfunction resulting in reduced ATP synthesis and impaired extramitochondrial Ca2+ movement. These factors are required for platelet activation, recruitment and clot stability likely thus, platelet mitochondrial dysfunction contributes to the development of TIC.

Clomazone herbicide impairs bioenergetics in mitochondria isolated from the thorax of honey bees (Apis mellifera L.)

The excessive use of pesticides on crops has caused an increase in animal mortality, contamination of soil, water and food, in addition to being identified as one of the causes of death of bees. Despite being quite effective, the herbicide clomazone (CLZ) causes widespread environmental contamination due to its high solubility in water (1,100 mg.L-1), and its residues can remain in the environment for up to 130 days. Mitochondria are responsible for producing the majority of the ATP in cells, and in bees, the thorax, as it is where the wings are located, is the place with the greatest ATP production. The objective of this work was to evaluate the effects of the herbicide CLZ on mitochondria isolated from the thorax of honey bees (Apis mellifera). The effects of CLZ (100, 125, 150, 200 and 250 µM) on mitochondria were evaluated by determining oxygen consumption, ATP production and generation of reactive oxygen species (ROS). When energized with pyruvate + malate (complex I substrates of the respiratory chain) CLZ did not show significant results in any of the concentrations used, however, when energized with succinate (complex II substrate of the respiratory chain) a dose-dependent stimulus in mitochondrial respiration was observed. Mitochondrial ATP levels were significantly reduced in a dose-dependent manner at concentrations above 125 µM. CLZ did not significantly induce the generation of ROS at any of the concentrations studied. Thus, the results of this study indicate that CLZ toxicity in honey bees may be related to changes in mitochondrial bioenergetics.

Implicaciones de la alimentación continua sobre la demanda de oxígeno en un pez agástrico con intestino corto (Teleostei: Atherinopsidae)

Continuous illumination and increased feeding periods have enhanced growth in commercial fish species. However, oxygen consumption under these conditions has yet to be previously assessed in agastric short-intestine fish. This study evaluated Chirostoma estor (Atherinopsidae) oxygen consumption under three specific feeding and light regimes: resting-unfed, routine-fed, and continuous light/feeding. Fish in the continuous light/feeding condition presented oxygen consumption levels 60 and 20% higher than resting-unfed and routine-fed fish, respectively. The latter implies that constant high oxygen supply levels are required to satisfy the demand for C. estor raised under these high growth rate conditions. The present study shows the relevance of determining oxygen consumption levels during continuous illumination and extended feeding periods to consider optimal oxygen levels required to achieve better performance indicators, such as the growth and welfare of atherinopsids and species with similar digestive configurations.

Scanning electrochemical microscopy for determining oxygen consumption rates of cells in hydrogel fibers fabricated using an extrusion 3D bioprinter

Three-dimensional (3D)-cultured cells have attracted the attention of researchers in tissue engineering- and drug screening-related fields. Among them, 3D cellular fibers have attracted significant attention because they can be stacked to prepare more complex tissues and organs. Cellular fibers are widely fabricated using extrusion 3D bioprinters. For these applications, it is necessary to evaluate cellular activities, such as the oxygen consumption rate (OCR), which is one of the major metabolic activities. We previously reported the use of scanning electrochemical microscopy (SECM) to evaluate the OCRs of cell spheroids. However, the SECM approach has not yet been applied to hydrogel fibers prepared using the bioprinters. To the best of our knowledge, this is the first study to evaluate the OCR of cellular fibers printed by extrusion 3D bioprinters. First, the diffusion theory was discussed to address this issue. Next, diffusion models were simulated to compare realistic models with this theory. Finally, the OCRs of MCF-7 cells in the printed hydrogel fibers were evaluated as a proof of concept. Our proposed approach could potentially be used to evaluate the OCRs of tissue-engineered fibers for organ transplantation and drug screening using in-vitro models.

The Effect of Exercise Intensity on Carbohydrate Sparing Postexercise: Implications for Postexercise Hypoglycemia.

The purpose of this study was to determine the effect of exercise intensity on the proportion and rate of carbohydrate oxidation and glucoregulatory hormone responses during recovery from exercise. Six physically active participants completed 1hr of low-intensity (LI; 50% lactate threshold) or moderate-intensity (MI; 100% lactate threshold) exercise on separate days following a randomized counterbalanced design. During exercise and for 6hr of recovery, samples of expired air were collected to determine oxygen consumption, respiratory exchange ratio, energy expenditure, and substrate oxidation rates. Blood samples were also collected to measure glucoregulatory hormones (catecholamines, GH) and metabolites (glucose, free fatty acids, lactate, pH, and bicarbonate). During exercise, respiratory exchange ratio, energy expenditure, and the proportion and rate of carbohydrate (CHO) oxidation were higher during MI compared with LI. However, during recovery from MI, respiratory exchange ratio and the proportion and rate of CHO oxidation were lower than preexercise levels and corresponding LI. During exercise and early recovery, catecholamines and growth hormone were higher in MI than LI, and there was a trend for higher levels of free fatty acids in the early recovery from MI compared with LI. In summary, CHO oxidation during exercise increases with exercise intensity but there is a preference for CHO sparing (and fat oxidation) during recovery from MI exercise compared with LI exercise. This exercise intensity-dependent shift in substrate oxidation during recovery is explained, in part, by the pattern of change of key glucoregulatory hormones including catecholamines and growth hormone and plasma fatty acid concentrations.

Diferentes métodos e tempos de medição para estimar a produção decalor em ovinos alimentados com farelo de girasssol

ABSTRACT: The objective of this study was to assess the oxygen pulse and heart rate method (O2P-HR) using a respiration chamber at different measurement times for estimate the heat production (HP) of lambs fed increasing levels of sunflower meal in their diet. Twenty-four lambs were assigned to four experimental diets (0, 100, 200, and 300 g of sunflower meal kg-1 DM). Heat production was estimated using the O2P-HR (HPO2P) method and a respirometry chamber (HPRC). Measurements were obtained by simultaneously measuring heart rate (HR) and oxygen consumption over 3, 6, 9, 12, 15, 18, 21 and 24 h. A flow-through respirometry chamber for small ruminants was used to determine oxygen consumption (VO2) and carbon dioxide and methane production. Data on dietary treatment, measurement times and their interactions were analyzed as repeated measures using mixed model procedures and Restricted Maximum Likelihood (REML) estimation. The Pearson’s correlation coefficient was used to compare techniques. There was no effect of the different levels of sunflower meal inclusion on VO2 and heat production. The HPO2P (126.16 kcal/ BW0.75/day) was 2% higher than that of the HPRC (124.61 kcal/ BW0.75/day), and the correlation coefficients was 0.628. The coefficient of variation was greater for the HPO2P (21.33%) than for HPRC (11.44%). HR (beats/min), VO2 (mL/min/BW0.75) and O2P-HR (mL/beat) required measurement times of 24, 15 and 9 hours, respectively. A measurement time of 24 h was necessary to ensure a more accurate estimate of the heat production using the O2P-HR method.

Clinical effectiveness of phospholipids in patients with restrictive respiratory failure due to lung tissue inflammation

Objective — to analyze the clinical effectiveness use of phosphatidylcholine liposomes in the treatment of patients with restrictive respiratory failure caused by acute pneumonia and pneumonia with a prolonged course.
 Materials and methods. A prospective cohort study of 68 people was conducted on the basis of the pulmonology department of the Kirovohrad Regional Hospital of the Kirovohrad Regional State in 2020—2021. The people were divided into two groups: I (n = 20) — control group, II (n = 48) — experimental group. They were composed of men aged 25 to 40 years. The first group consisted of healthy individuals who underwent a preventive examination. The second group included patients who, in addition to the traditional treatment of pneumonia, were treated with phospholipids in liposomal form. The drug was used by inhalation according to the instructions. In the course of the experiment, the volume-time indicators of external respiration and gas exchange of the body were studied in dynamics.
 Results and discussion. The introduction of phospholipids in liposomal form had a positive effect on the restoration of the function of external respiration from the 5th day of treatment of the disease. This is evidenced by the gradual normalization of breathing rate and respiratory volume. It was shown that the ratio of alveolar ventilation and minute respiratory volume was significantly lower and ranged from 60.3 to 72.7 % (with a control value of 72.2 to 77.4 %). Oxygen consumption increased by approximately 76 % on the 5th day of the disease, which indicates a pronounced increase in the level of oxidative metabolism in the body during this pathological process. Recovery could be observed due to optimization of the body’s oxygen supply. Regarding carbon dioxide release, this indicator was almost 2.3 times higher than the control values ​​on the 5th day of the disease. This contributes to the development of metabolic acidosis, which in turn leads to respiratory alkalosis. Against the background of phosphatidylcholine liposomes treatment, this indicator gradually decreased and had a tendency to approach control values ​​a month after treatment (0.216 ± ± 0.042) l/min). Another of the studied indicators is the dead breathing space. According to this indicator, the efficiency of external breathing also increased. The minute volume of blood flow in healthy individuals was (6.5 ± 0.7). During the disease, it decreased to (4.7 ± 0.8) with gradual recovery, starting from the 10th day of treatment with phospholipids. There is also a decrease in the oxygen saturation of the arterial blood and a decrease in the use of oxygen, which can be judged by the characteristics of the venous blood; at the same time, the determined oxygen consumption increases due to hyperventilation. One month after the treatment, these indicators were no longer significantly different from the control values. A similar trend is noted in the analysis of oxygen tension in arterial and venous blood, with a gradual normalization of indicators against the background of the use of phosphatidylcholine liposomes. The determination of the alveolar-arterial difference in oxygen showed an increase in the indicator in the experimental group compared to the control group. Most of the indicators we studied contributed to the decrease in oxygen, thus increasing the efficiency of external respiration.
 Conclusions. Phosphatidylcholine liposomes are an effective means of complex therapy of pneumonia. The drug has a normalizing effect on the level of energy metabolism in the body and normalizes oxygen consumption, contributing to a faster recovery of the optimal intensity of metabolic processes.

Impact of sustained de novo lipogenesis on mitochondrial dysfunction and hepatocellular redox during fatty liver disease

Dysfunctional mitochondrial metabolism and sustained de novo lipogenesis are characteristic of non-alcoholic fatty liver disease (NAFLD), a common comorbidity of obesity and type 2 diabetes. We hypothesize that sustained de novo lipogenesis, through its biochemical relationships with mitochondria (e.g., tri-carboxylic acid (TCA) cycle) can contribute to dysfunctional oxidative flux during NAFLD. In study 1, male mice (C57BL/6JN) were fed either a low-fat (LF; 10% fat Kcal), high-fat (HF; 60% fat Kcal), or high-fructose/HF diet (HFr/HF; 34.9% fructose Kcal, 25% fat Kcal) for 24-wks. Liver mitochondria were utilized to determine oxygen consumption and were incubated in a buffer (for 5-min) to determine changes in TCA cycle intermediates, using gas chromatography-mass spectrometry (GC-MS). Plasma and liver samples were utilized for GC-MS based metabolomics and determination of gene and protein expression. In study 2, C57BL/6JN mice were provided 30% fructose in drinking water (FW) for 2-wks to induce hepatic de novo lipogenesis vs. mice given regular water (RW). Liver mitochondria were incubated in a buffer containing 1mM [ 13 C 3 ]pyruvate or 2.5mM [ 13 C 4 ]malate for 5-min. Isotopomer distribution of the TCA cycle intermediates were determined using GC-MS. Both HF and HFr/HF diets resulted in similar degrees of hepatic steatosis. However, lipogenic gene expression ( Scd1, Acyl, Fasn) and fasting plasma β-hydroxybutyrate levels were higher (p<0.001) in HFr/HF vs. HF group. Further, the feeding-to-fasting induction of genes involved in lipid oxidation ( Cpt1α, Lcad, Hmgcs2) was higher (p ≤0.01) in HFr/HF vs. HF livers. After 5-min of incubation, the HFr/HF liver mitochondria had higher (p<0.05) TCA cycle intermediates vs. the HF. The HFr/HF mitochondria also had higher expression of oxidative phosphorylation proteins and higher oxygen consumption rates (OCR), vs. the HF (p<0.05). In study 2, fructose in drinking water induced hepatic de novo lipogenesis. Induction of lipogenesis was also accompanied by higher mitochondrial OCR, higher reactive oxygen species, and higher TCA cycle metabolism (p<0.05). Gene expression of components of the mitochondrial nutrient shuttles ( SLC25A13, MPC1, MPC2, ME1) was upregulated in lipogenic livers (p<0.05). Incorporation of 13 C from [ 13 C 4 ]malate into pyruvate and α-ketoglutarate, indices of malic enzyme and TCA cycle activity, were higher (p<0.05) in lipogenic livers. Similarly, incorporation of 13 C from [ 13 C 3 ]pyruvate into aspartate and citrate, indices of pyruvate carboxylase and pyruvate dehydrogenase activity, were also higher (p<0.05) in lipogenic livers. These results demonstrate that the induction of several facets of mitochondrial oxidative metabolism and de novo lipogenesis accompany a carbohydrate-rich dietary milieu and NAFLD. Sustained induction of both de novo lipogenesis and mitochondrial oxidative function could contribute to the progression of metabolic dysfunction during NAFLD. National Institutes of Health R01 DK112865 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Bioenergetic changes and mitochondrial dysfunction in mania versus euthymia in bipolar disorder type I

IntroductionCurrent evidence has hypothesized the involvement of mitochondrial dysfunction during the acute episodes of BD compared to symptomatic remission. So far, no studies have compared mitochondrial and bioenergetic functions both in-vivo (respiratory parameters) and ex-vivo (cellular respiration) in different phases of the disease in the same individuals.ObjectivesThis multidisciplinary pilot study aims at assessing bioenergetic and mitochondrial intra-individual differences between manic and euthymic states.MethodsFour patients with a manic episode admitted to our acute psychiatric ward were recruited. Bioenergetic parameters were measured at admission (T0) and after symptomatic remission (T1).At admission (T0) and before discharge (T1), HAMD and YMRS total scores were obtained. For the assessment of cellular respiration, polymorphonuclear cells were obtained by a Ficoll density gradient centrifugation procedure. To determine oxygen consumption (at T0 and T1), a million of living peripheral blood mononuclear cells (PBMC) were used. High-resolution respirometry was performed at 37°C by polarographic oxygen sensors in a two-chamber Oxygraph-2k system.Specific oxygen uptakes (Routine: basal oxygen consumption; Proton Leak: oxygen consumption not coupled to ATP synthesis; and ETC: maximal capacity of the electron transport chain) rates were obtained using mitochondrial chain inhibitors and uncouplers. Oxygen consumption was normalized for protein concentration. Results are expressed as picomoles of oxygen per millilitre (pmol O2/s*μg prot).Also, a constant work rate exercise test was performed on a cycle ergometer and basal and effort respiratory variables were measured.Statistical analysis was performed with the SPSS v. 25.0 and GraphPad. Results were expressed as means and SD. Nonparametric tests (Mann–Whitney, Pearson) were used to determine differences (significant at p value <0.05).ResultsOne patient was a man and three patients were women, with a mean age of 28 years old. HAMD initial and final mean scores were 11.0 and 7.0, and mean YMRS scores were 21.5 and 7.0 respectively.Results from mitochondrial oxygen consumption revealed that mean basal oxygen consumption tended to be higher in T1 (0.98±0.45) than in T0, and maximal respiratory capacity was significantly increased in T1 (2.26±0.33; p=0.028) compared to T0.Mean lactate levels and pH levels were similar in T0 and T1. Scales scores were not correlated to different pH or lactate changes after the effort task. Higher initial oxygen consumption was significantly correlated to higher maximal capacity (p<0.05) in T0 and T1.Image:ConclusionsOur preliminary results suggest that mania could imply lower oxygen consumption capacity, which should be confirmed in future studies. A bigger study is planned to determine changes in bioenergetic patterns and capacity for aerobic response in manic and depressive episodes.Disclosure of InterestNone Declared

P047 Osteopontin in colitis-associated carcinoma (CAC)

Abstract Background Inflammatory bowel disease (IBD) patients pose a lifelong risk of developing colitis-associated carcinoma (CAC). Current understanding and mechanisms of CAC development stem from murine CAC models while studies on human CAC carcinogenesis are scarce. Thus, we aimed to understand CAC carcinogenesis, using human samples from patients suffering from Crohn′s disease (CD), CD-associated CAC (CD-CAC), ulcerative colitis (UC), and UC-associated CAC (UC-CAC) and further validated the findings in vitro. Methods We obtained FFPE specimens from 40 patients that suffered from either one of the IBDs or CACs and furthermore inflammation-free healthy controls (10 patients per group). These samples were micro-dissected, followed by RNA isolation and Nanostring gene expression analysis. Our data revealed a strong upregulation of SPP1 (Secreted Phosphoprotein-1) gene encoding for osteopontin (OPN) upon comparing heathy controls to IBD and to CAC. We then used in vitro-models to elucidate the mechanism of OPN-induced carcinogenesis. We stimulated intestinal epithelial cell lines HT-29/B6 and T84 cells with rhOPN (recombinant human OPN), following bulk RNAseq. We validated the findings using Seahorse assay for analysis of mitochondrial respiration (determining oxygen consumption rate, OCR). Western phospho-blots were done to unravel signal transduction events. Results Nanostring gene expression data revealed the following: (i) SPP1 gene encoding for OPN and epithelial-to-mesenchymal (EMT) transcription factors fibronectin-1 (FN1) and ZEB1 were strongly upregulated in UC-CAC and CD-CAC patients when compared to UC and CD. (ii) IL17-pathway genes were significantly downregulated in UC-CAC patients. (iii) Tight junction and polarity genes were altered in both UC-CAC and CD-CAC patients. rhOPN stimulation in vitro to HT29/B6 and T84 cells excluded OPN as the trigger of EMT but uncovered upregulated mitochondrial respiratory chain genes as a potential trigger for tumour cell proliferation. Validation of RNAseq findings by Seahorse assay revealed that after sequential injections of oligomycin, FCCP, rotenone and antimycin A both, HT-29/B6 and T84 cells, had higher basal and maximal OCRs in response to rhOPN (Fig. 1). T84, but not HT-29/B6 cells also showed an upregulated ATP production in response to rhOPN. Conclusion SPP1 expression correlates with CAC carcinogenesis. Putative underlying pathways rather include modulation of mitochondrial respiratory chain activity by differential gene expression than induction of EMT.

Hybrid Model for Predicting Oxygen Consumption in BOF Steelmaking Process Based on Cluster Analysis

The amount of oxygen blown into the converter directly affects the productivity of the converter and the quality of the molten steel, so it is crucial to accurately predict oxygen consumption. Herein, a hybrid model for predicting oxygen consumption in basic oxygen furnace steelmaking process is established. The oxygen consumption of converter is divided into two types: the determined oxygen consumption and the estimated oxygen consumption. The determined oxygen consumption is calculated by mechanism model. And the estimated oxygen consumption is calculated by statistical model. The method of cluster analysis is also introduced into the model. After clustering the data, a statistical model for predicting the estimated oxygen consumption in each subcategory is established, which further improves the prediction accuracy of the model. After dividing the original data into three categories, the hit rate of the hybrid model is 93.3%, when the relative errors of the model are restricted within 5%. As a result, the hybrid model is fully capable of predicting oxygen consumption in converters.

THE CLUE IS IN THE BLOOD GAS: A RARE MANIFESTATION OF LACTIC ACIDOSIS

THE CLUE IS IN THE BLOOD GAS: A RARE MANIFESTATION OF LACTIC ACIDOSIS

Determining Oxygen Consumption of Indonesian Mahseer (Tor soro) Fingerlings at Different Size and Stocking Density

Understanding oxygen consumption in fish is one of the essential factors in the survival performance of cultured fish. As this information is established, the appropriate size and optimum stocking density of cultured fish reared in an aquaculture system can be determined for successful larval rearing of mahseer in a hatchery. This study aimed to obtain information on the oxygen consumption rate and critical oxygen level of Indonesian mahseer fingerlings at different sizes and stocking densities. This study was conducted in the Laboratory of Fish Reproduction and Genetics, which belongs to the Research Institute for Freshwater Aquaculture and Fisheries Extension, Bogor. A factorial design with two factors (size and stocking density) and three replications were employed to run the experiments. Oxygen consumption rate was measured using a closed respirometer system (volume: 1.4 L) Parameters observed during the study are oxygen consumption rate and critical oxygen level. The results showed that the highest oxygen consumption rate was found at the size of 6-8 cm at 9.52 mg O2/g/minute with a stocking density of 7 fish/1.4 L. Oxygen consumption rate of mahseer was increased with the increase of size and stocking density. In this experiment, the critical oxygen level of mahseer fingerlings was observed at 1.44 mg/L. The obtained critical oxygen consumption could be used as a reference to determine the amount of dissolved oxygen that could support the survival rate of mahseer. In rearing practice, it would be important information used for designing early warning and mitigating culture systems to avoid deterioration of dissolved oxygen levels in the water. Therefore, this study can be recommended for improvement mahseer rearing practice for better hatchery production with providing an appropriate oxygenation system for fingerling growth.

Role of Grape-Extractable Polyphenols in the Generation of Strecker Aldehydes and in the Instability of Polyfunctional Mercaptans during Model Wine Oxidation.

Polyphenolic fractions from Garnacha, Tempranillo, and Moristel grapes were reconstituted to form model wines of identical pH, ethanol, amino acid, metal, and varietal polyfunctional mercaptan (PFM) contents. Models were subjected to a forced oxidation procedure at 35 °C and to an equivalent treatment under strict anoxia. Polyphenolic profiles significantly determined oxygen consumption rates (5.6–13.6 mg L–1 day–1), Strecker aldehyde (SA) accumulation (ratios max/min around 2.5), and levels of PFMs remaining (ratio max/min between 1.93 and 4.53). By contrast, acetaldehyde accumulated in small amounts and homogeneously (11–15 mg L–1). Tempranillo samples, with highest delphinidin and prodelphinidins and smallest catechin, consume O2 faster but accumulate less SA and retain smallest amounts of PFMs under anoxic conditions. Overall, SA accumulation may be related to polyphenols, producing stable quinones. The ability to protect PFMs as disulfides may be negatively related to the increase in tannin activity, while pigmented tannins could be related to 4-methyl-4-mercaptopentanone decrease.

Inhibiting DNA methylation alleviates cisplatin-induced hearing loss by decreasing oxidative stress-induced mitochondria-dependent apoptosis via the LRP1–PI3K/AKT pathway

Cisplatin-related ototoxicity is a critical side effect of chemotherapy and can lead to irreversible hearing loss. This study aimed to assess the potential effect of the DNA methyltransferase (DNMT) inhibitor RG108 on cisplatin-induced ototoxicity. Immunohistochemistry, apoptosis assay, and auditory brainstem response (ABR) were employed to determine the impacts of RG108 on cisplatin-induced injury in murine hair cells (HCs) and spiral ganglion neurons (SGNs). Rhodamine 123 and TMRM were utilized for mitochondrial membrane potential (MMP) assessment. Reactive oxygen species (ROS) amounts were evaluated by Cellrox green and Mitosox-red probes. Mitochondrial respiratory function evaluation was performed by determining oxygen consumption rates (OCRs). The results showed that RG108 can markedly reduce cisplatin induced damage in HCs and SGNs, and alleviate apoptotic rate by protecting mitochondrial function through preventing ROS accumulation. Furthermore, RG108 upregulated BCL-2 and downregulated APAF1, BAX, and BAD in HEI-OC1 cells, and triggered the PI3K/AKT pathway. Decreased expression of low-density lipoprotein receptor-related protein 1 (LRP1) and high methylation of the LRP1 promoter were observed after cisplatin treatment. RG108 treatment can increase LRP1 expression and decrease LRP1 promoter methylation. In conclusion, RG108 might represent a new potential agent for preventing hearing loss induced by cisplatin via activating the LRP1-PI3K/AKT pathway.

Association between cardiac high-energy phosphate metabolism and whole body metabolism in healthy female adults.

Decline in cardiac high-energy phosphate metabolism [phosphocreatine-to-ATP (PCr/ATP) ratio] and whole body metabolism increase the risk of heart failure and metabolic diseases. The aim of the present study was to assess the relationship between PCr/ATP ratio and measures of body metabolic function. A total of 35 healthy women (56+/-14.0 years of age) underwent cardiac 31P magnetic resonance spectroscopy to assess PCr/ATP ratio - an index of cardiac high-energy phosphate metabolism. Fasting and 2-hour glucose levels were assessed using oral glucose tolerance test. Indirect calorimetry was performed to determine oxygen consumption and resting metabolic rate. There were no significant relationships between PCr/ATP ratio and resting metabolic rate (r=-0.09, p=0.62), oxygen consumption (r=-0.11, p=0.54), fasting glucose levels (r=-0.31, p=0.07), and 2-hour plasma glucose (r=-0.10, p=0.58). Adjusted analysis for covariates including age, body mass index, fat mass, and physical activity, had no significant influence on the relationship between PCr/ATP ratio and body metabolism. In conclusion, the lack of relationship between cardiac PCr/ATP ratio, glucose control and metabolic rate may suggest that overall metabolic function does not influence cardiac high-energy phosphate metabolism.

Valores normativos del consumo de oxígeno máximo en las personas mayores de los centros día de la ciudad de Tunja, Colombia

ObjectiveTo determine the normative values of oxygen consumption in older adults in the day centres of the city of Tunja, Colombia. Materials and methodsA descriptive cross-sectional study was carried out with a sample size of 121 participants, to whom the modified Bruce protocol was applied to determine oxygen consumption, building from these results the percentile distribution using the method of least squares, through R Studio® statistical software. ResultsThe average age of the participants was 70.98 ± 8.8 years, the female gender and the presence of comorbidities prevailed. An inverse relationship between age and VO2 max was found in the results, showing that the older the age, the lower the oxygen consumption (p < 0.05; Rho -0.42). ConclusionsA normalization model for oxygen consumption given in MET and in mL/kg/min is presented, providing standards at the national and regional level valid reference values for the elderly, being applicable in evaluation and intervention processes.

Group swimming behaviour and energetics in bluegill Lepomis macrochirus and rainbow trout Oncorhynchus mykiss.

Group swimming size influences metabolic energy consumption and swimming behaviour in fishes. Hydrodynamic flows and vortices of other fish are thought to be beneficial in terms of the energetic costs of swimming. Similarly, abiotic obstructions have been shown to have similar benefits with respect to metabolic consumption in swimming fish such as rainbow trout Oncorhynchus mykiss. The current study works to examine metabolic rates and swimming behaviours as a function of group swimming with bluegill sunfish Lepomis macrochirus and O. mykiss. Fishes were subjected to individual and group swimming in a respiratory swim tunnel to determine oxygen consumption as a proxy for the metabolic rate of swimming fish. In addition, fish movements within the swim tunnel test chamber were tracked to examine group swimming behaviour. We hypothesized that fish would benefit metabolically from group swimming. In the case of O. mykiss, we also hypothesized that groups would benefit from the presence of an abiotic structure, as has been previously observed in fish swimming individually. Our results suggest that the influence of group size on swimming metabolism is species specific. While L. macrochirus show decreased metabolic rate when swimming in a group compared to individually, O. mykiss did not show such a metabolic benefit from group swimming.

110 Metmyoglobin reducing activity and oxygen consumption properties of atypical dark-cutting beef

Abstract Deviation from characteristic bright-red color during grading leads to discounted carcass price and value. Dark-cutting carcasses are examples of color deviation due to high-pH. However, atypical dark-cutters are not discounted at grading but have a dark color compared to normal-pH beef. Limited knowledge is currently available on the biochemical properties of atypical dark cutting beef compared with normal-pH beef. Therefore, the objective of the study was to determine metmyoglobin reducing activity and oxygen consumption of atypical dark-cutting beef. Strip loins from atypical dark-cutting (ADC; selected based on HunterLab L* values and pH less than 5.8 and not discounted by grader) and USDA Low Choice (C) carcasses were selected from a commercial beef processing plant and transported to the Food and Agricultural Products Center in Stillwater, Oklahoma. pH, color, oxygen consumption, and metmyoglobin reducing activity of atypical dark cutters and normal pH loins were determined on d3 postmortem. The surface color was determined using a HunterLab Miniscan spectrophotometer. Reflectance-based methods using K/S ratios were utilized to determine oxygen consumption and metmyoglobin reducing activity. The data were analyzed using the Mixed Procedure of SAS and the experiment was replicated 10 times (n = 10). There were no differences in initial pH (C = 5.46 and ADC = 5.6 atypical dark-cutter; P = 0.05) between normal-pH and atypical dark cutters. However, atypical dark cutters had lower lightness (L* values; C = 44.2 and ADC = 38.4), redness (a* values; C = 28.6 and ADC = 25.2), and red intensity (chroma; C = 40.2 and ADC = 36.4) compared with normal-pH. Further, atypical dark cutters had greater (P &amp;lt; 0.05) oxygen consumption and metmyoglobin reducing activity than normal-pH. The results suggest that atypical dark cutters and normal-pH beef have different biochemical properties.