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• Roots in flooded soils experience hypoxia, with the least O₂ in the vascular cylinder. Gradients in CO₂ across roots had not previously been measured. The respiratory quotient (RQ; CO₂ produced :O₂ consumed) is expected to increase as O₂ availability declines. • A new CO₂ microsensor and an O₂ microsensor were used to measure profiles across roots of chickpea seedlings in aerated or hypoxic conditions. Simultaneous, nondestructive flux measurements of O₂ consumption, CO₂ production, and thus RQ, were taken for roots with declining O₂. • Radial profiling revealed severe hypoxia and c. 0.8 kPa CO₂ within the root vascular cylinder. The distance penetrated by O₂ into the roots was shorter at lower O₂. The gradient in CO₂ was in the opposite direction to that of O₂, across the roots and diffusive boundary layer. RQ increased as external O₂ was lowered. • For chickpea roots in solution at air equilibrium, O₂ was very low and CO₂ was elevated within the vascular cylinder; the extent of the severely hypoxic core increased as external O₂ was reduced. The increased RQ in roots in response to declining external O₂ highlighted the shift from respiration to ethanolic fermentation as the severely hypoxic/anoxic core became a progressively greater proportion of the root tissues.

BackgroundThe growth of Aspergillus awamori and Aspergillus oryzae in a self-designed, multi-stacked circular tray solid-state bioreactor (SSB), operating in solid-state fermentation (SSF) conditions at a laboratory scale, was studied. The bioreactor was divided into six layers by six circular perforated trays. Wheat bran was used as both a carrier of bound mycelia and nutrient medium for the growth of A. awamori and A. oryzae. The new tray SSB is equipped with instrumentation (an oxygen (O2)/carbon dioxide (CO2) gas analyser and a thermocouple) to continuously monitor O2 consumption and CO2 and heat evolved, which can directly be used to monitor the fungal biomass. The integrated Gompertz model was used to describe the accumulated evolution of CO2.ResultsThe results from the models strongly suggest that the evolved and accumulated CO2 can be used to excellently describe fungal growth. Another important parameter that can be determined by the gas balance method is the respiratory quotient (RQ). This is the ratio of the CO2 evolution rate (CER) to the O2 uptake rate (OUR). The use of CER and OUR confirmed that correlated measurements of microbial activity are available, and the determination of RQ may propose an explanation for differences from expected levels. The kinetic behaviour of the fungal culture, using raw CO2, which represents an accumulation term, was integrated with respect to time and fitted to a Gompertz model, a log-like equation. The model can be used to generate parameter values that may be used to verify the experimental data, and also to simulate and optimise the process.ConclusionOverall, A. awamori and A. oryzae have their own ability to degrade and utilise the complex compositions contained in the solid substrate, and fermentation conditions may lead to possible comparisons. In addition, multi-stacked circular tray SSB systems demonstrated an excellent system for further investigations of mass transfer and possibly for large-scale operation, though considerable optimisation work remains to be done; for example, the height/diameter ratio and total number of trays should be optimised.

Background: Branched chain amino acids (BCAA) supplementation is reported to aid in lean mass preservation, which may in turn minimize the reduction in resting metabolic rate (RMR) during weight loss. Our study aimed to examine the effect of BCAA supplementation to a hypocaloric diet on RMR and substrate utilization during a weight loss intervention. Methods: A total of 111 Chinese subjects comprising 55 males and 56 females aged 21 to 45 years old with BMI between 25 and 36 kg/m2 were randomized into three hypocaloric diet groups: (1) standard-protein (14%) with placebo (CT), (2) standard-protein with BCAA, and (3) high-protein (27%) with placebo. Indirect calorimetry was used to measure RMR, carbohydrate, and fat oxidation before and after 16 weeks of dietary intervention. Results: RMR was reduced from 1600 ± 270 kcal/day to 1500 ± 264 kcal/day (p < 0.0005) after weight loss, but no significant differences in the change of RMR, respiratory quotient, and percentage of fat and carbohydrate oxidation were observed among the three diet groups. Subjects with BCAA supplementation had an increased postprandial fat (p = 0.021) and decreased postprandial carbohydrate (p = 0.044) oxidation responses compared to the CT group after dietary intervention. Conclusions: BCAA-supplemented standard-protein diet did not significantly attenuate reduction of RMR compared to standard-protein and high-protein diets. However, the postprandial fat oxidation response increased after BCAA-supplemented weight loss intervention.

The success of performance in basketball relies on both optimal body composition and nutrient intake. The purpose of this study was to examine seasonal changes in body composition (BC), resting metabolic rate (RMR) and respiratory quotient (RQ), as well as dietary intake of National Collegiate Athletic Association (NCAA) Division I (DI) male basketball players. BC, RMR and RQ were assessed during pre-season, in-season, and post-season (September, December, and March) while dietary assessment data were collected in September and February. Results of this study indicated that players received inadequate energy (p < 0.0001), protein (p < 0.001) and carbohydrate (p < 0.0001) relative to the recommendations for exercising individuals during the September baseline period. However, following diet analysis and consultations and relative to recommendations, athletes received adequate amounts of energy and protein during follow-up, yet intakes of carbohydrate (p = 0.0025) were still significantly different than recommended. Results also indicated that there was a decrease in percent body fat (%BF) during season, an increase in lean body mass (LBM) from pre- to post-season, a peak in RMR during season and an increase in RQ post-season. These findings reveal that significant metabolic and body composition changes occur in players over the season and suggest that nutritional strategies employed concomitantly may be beneficial.

Perioperative nutritional assessment is critically important to reflect nutritional management because liver transplantation (LTx) often is undertaken in patients with poor nutritional status. The aim of this study was to evaluate nutritional status, including the non-protein respiratory quotient (npRQ), resting energy expenditure (REE), nitrogen balance, and blood biochemical parameters in patients before and after LTx. Fourteen patients undergoing LTx and 10 healthy controls were enrolled in this study. The npRQ and REE were measured using indirect calorimetry before LTx and at 2, 3, and 4 wk after the procedure. Blood biochemistry and nitrogen balance calculated by 24-h urine collection were performed concurrently with indirect calorimetric measurement; the results were compared between the two groups. Before LTx, npRQ was significantly lower and serum non-esterified fatty acid levels were significantly higher in the patients than in the controls. Furthermore, a negative nitrogen balance was observed in the patients. These, however, improved significantly at 4 wk after LTx. REE did not significantly increase compared with the preoperative values in recipients. Blood biochemistry showed gradually increasing levels of serum cholinesterase and albumin. These failed to reach to normal levels by 4 wk post-transplant. The findings revealed that improvement of nutritional metabolism after LTx may require 4 wk. Additional nutritional strategies, therefore, may be needed to minimize catabolic state during the early post-transplant period. Adequate, individualized nutritional guidance before and after LTx should be performed in these patients.

Aspergillus awamori and Aspergillus oryzae were cultivated on wheat bran in newly designed single circular tray solid state bioreactor (SSB) systems. The effect of aeration arrangements on moisture content, oxygen (O 2 ) supply, carbon dioxide (CO 2 ) evolution during solid state fermentation (SSF) was investigated. The purpose was to study the effect on oxygen uptake rate (OUR) and carbon dioxide evolution rate (CER), of operating variables, fermentation on the perforated base tray and internal moist air circulation under natural and forced aeration. Temperature, O 2 and CO 2 were measured continuously on-line. Final moisture content was also measured. A direct technique of establishing a correlation among fungal growth, CER and OUR were proven successful in this work. The information obtained from CER and OUR led to the estimation of respiratory quotient (RQ). RQ describes the state of the fungal population in the tray SSB and gives an indication of fungal metabolic behaviour. RQ values <1 were obtained from 14 experiments using single circular tray SSB system for the two fungi. A Gompertz model was used to fit the integrated CO 2 data and predict the quantity of CO 2 evolution in all experiments. A correlation was found between the RQ and CO 2 evolution. The aeration strategies and arrangements applied in these studies exceeded the optimum requirements and allowed accurate measurements of gas composition, temperature, moisture content and fungal biomass gradients. The model system developed in this study may provide an excellent system for further investigations of mass transfer and possibly for large scale operation.

Perioperative nutritional care is important to maintain preoperative and postoperative nutritional status. However, few reports have investigated energy metabolism after hepatectomy. The aim of this study was to determine differences in energy metabolism, blood biochemistry, and nutritional status before and after liver resection in patients with hepatocellular carcinoma (HCC) and healthy living donors for liver transplantation. Eighteen hospitalized patients with HCC group and 13 living donors for liver transplantation (donor group) were enrolled in this study. The donor group was divided into two groups on the basis of age; Y-donor group (age < 40 y, n = 7), and O-donor group (age ≥ 40 y, n = 6). Energy metabolism was measured by indirect calorimetry at preoperative day and postoperative day (POD) 7 and 14, and blood biochemistry was also examined. Recovery of non-protein respiratory quotient (npRQ) and blood biochemical data such as total bilirubin, aspartate aminotransferase and alanine aminotransferase levels were observed in Y-donor group on POD 14. However, although biochemical data improved in the HCC and O-donor group, npRQ remained unchanged on POD 14. Improvement of npRQ took longer than blood biochemical data in patients with HCC and older donors. Because the recovery of npRQ is associated with donor age, careful nutritional management may be required for a longer time depending on the pathophysiological condition of each patient after hepatectomy.

Shift work causes circadian misalignment and is a risk factor for obesity. While some characteristics of the human circadian system and energy metabolism differ between males and females, little is known about whether sex modulates circadian misalignment effects on energy homeostasis. Here we show—using a randomized cross-over design with two 8-d laboratory protocols in 14 young healthy adults (6 females)—that circadian misalignment has sex-specific influences on energy homeostasis independent of behavioral/environmental factors. First, circadian misalignment affected 24-h average levels of the satiety hormone leptin sex-dependently (P < 0.0001), with a ∼7% decrease in females (P < 0.05) and an ∼11% increase in males (P < 0.0001). Consistently, circadian misalignment also increased the hunger hormone ghrelin by ∼8% during wake periods in females (P < 0.05) without significant effect in males. Females reported reduced fullness, consistent with their appetite hormone changes. However, males reported a rise in cravings for energy-dense and savory foods not consistent with their homeostatic hormonal changes, suggesting involvement of hedonic appetite pathways in males. Moreover, there were significant sex-dependent effects of circadian misalignment on respiratory quotient (P < 0.01), with significantly reduced values (P < 0.01) in females when misaligned, and again no significant effects in males, without sex-dependent effects on energy expenditure. Changes in sleep, thermoregulation, behavioral activity, lipids, and catecholamine levels were also assessed. These findings demonstrate that sex modulates the effects of circadian misalignment on energy metabolism, indicating possible sex-specific mechanisms and countermeasures for obesity in male and female shift workers.

Purpose To evaluate the prognostic value of the Cv-aCO 2 /Da-vO 2 ratio combined with lactate levels during the early phases of resuscitation in septic shock. Methods Prospective observational study in a 60-bed mixed ICU. One hundred and thirty-five patients with septic shock were included. The resuscitation protocol targeted mean arterial pressure, pulse pressure variations or central venous pressure, mixed venous oxygen saturation, and lactate levels. Patients were classified into four groups according to lactate levels and Cv-aCO 2 /Da-vO 2 ratio at 6 h of resuscitation (T6): group 1, lactate ≥2.0 mmol/L and Cv-aCO 2 /Da-vO 2 >1.0; group 2, lactate ≥2.0 mmol/L and Cv-aCO 2 /Da-vO 2 ≤1.0; group 3, lactate <2.0 mmol/L and Cv-aCO 2 /Da-vO 2 >1.0; and group 4, lactate <2.0 mmol/L and Cv-aCO 2 /Da-vO 2 ≤1.0. Results Combination of hyperlactatemia and high Cv-aCO 2 /Da-vO 2 ratio was associated with the worst SOFA scores and lower survival rates at day 28 [log rank (Mantel–Cox) = 31.39, p  < 0.0001]. Normalization of both variables was associated with the best outcomes. Patients with a high Cv-aCO 2 /Da-vO 2 ratio and lactate <2.0 mmol/L had similar outcomes to hyperlactatemic patients with low Cv-aCO 2 /Da-vO 2 ratio. The multivariate analysis revealed that Cv-aCO 2 /Da-vO 2 ratio at both T0 (RR 3.85; 95 % CI 1.60–9.27) and T6 (RR 3.97; 95 % CI 1.54–10.24) was an independent predictor for mortality at day 28, as well as lactate levels at T6 (RR 1.58; 95 % CI 1.13–2.22). Conclusion Complementing lactate assessment with Cv-aCO 2 /Da-vO 2 ratio during early stages of resuscitation of septic shock can better identify patients at high risk of adverse outcomes. The Cv-aCO 2 /Da-vO 2 ratio may become a potential resuscitation goal in patients with septic shock.

Background/ObjectiveFemale mice are often excluded from diet-induced obesity studies as they are more resistant to the obesifying effects of a high-fat diet (HFD). However, the underlying mechanisms behind this sex disparity may actually have important implications for the development and management of obesity in humans. Therefore, we systematically investigated the immediate sex-specific effects of transitioning to a HFD in C57BL/6J mice as well as monitored whether these effects are altered after sustained HFD feeding and whether sex affects the response to a return to chow, representative of dieting.MethodsDual X-ray absorptiometry (DXA) analysis of body composition, indirect calorimetry measurements, and qPCR analysis of hypothalamic and brainstem regions were performed on male and female C57BL/6J mice.ResultsHFD had immediate and dramatic effects in males, increasing fat mass by 58% in the first 3 days. The resistance to the obesifying effect of HFD in females was linked both to an ability to maintain activity levels as well as to an immediate and significantly enhanced reduction in respiratory quotient (RQ), suggesting a greater ability to utilise fat in the diet as a source of fuel. Mechanistically, this sex disparity may be at least partially due to inherent sex differences in the catabolic (POMC/CART) versus anabolic (NPY/AgRP) neurological signalling pathways. Interestingly, the reintroduction of chow following HFD had immediate and consistent responses between the sexes with body composition and most metabolic parameters normalised within 3 days. However, both sexes displayed elevated hypothalamic Npy levels reminiscent of starvation. The difference in RQ seen between the sexes on HFD was immediately abolished suggesting similar abilities to burn fat reserves for fuel.ConclusionsC57BL/6J mice have markedly different sex-specific behavioural and metabolic responses to the introduction as well as the sustained intake of a HFD, but consistent responses to a dieting situation.