► FOS were produced in a one stage-process. ► Optimized production yield was 64.1 (±0.0)gFOS/gsucrose. ► Optimum fermentation conditions were 32°C and 385rpm.
Fructooligosaccharides are prebiotics ...with numerous health benefits within which the improvement of gut microbiota balance can be highlighted, playing a key role in individual health. In this study, an integrated one-stage method for FOS production via sucrose fermentation by Aureobasidium pullulans was developed and optimized using experimental design tools. Optimization of temperature and agitation speed for maximizing the FOS production was performed using response surface methodology. Temperature was found to be the most significant parameter. The optimum fermentation conditions were found to be 32°C and 385rpm. Under these conditions, the model predicted a total FOS production yield of 64.7gFOS/gsucrose. The model was validated at optimal conditions in order to check its adequacy and accuracy and an experimental yield of 64.1 (±0.0)gFOS/gsucrose was obtained. A significant improvement of the total FOS production yields by A. pullulans using a one-stage process was obtained.
Understanding how tropical forest carbon balance will respond to global change requires knowledge of individual heterotrophic and autotrophic respiratory sources, together with factors that control ...respiratory variability. We measured leaf, live wood, and soil respiration, along with additional environmental factors over a 1-yr period in a Central Amazon terra firme forest. Scaling these fluxes to the ecosystem, and combining our data with results from other studies, we estimated an average total ecosystem respiration ($R_{eco}$) of$7.8 \mumol\cdot m^{-2}\cdot s^{-1}$. Average estimates (per unit ground area) for leaf, wood, soil, total heterotrophic, and total autotrophic respiration were$2.6, 1.1, 3.2, 5.6, and 2.2 \mumol\cdot m^{-2}\cdot s^{-1}$, respectively. Comparing autotrophic respiration with net primary production (NPP) estimates indicated that only ~30% of carbon assimilated in photosynthesis was used to construct new tissues, with the remaining 70% being respired back to the atmosphere as autotrophic respiration. This low ecosystem carbon use efficiency (CUE) differs considerably from the relatively constant CUE of ~0.5 found for temperate forests. Our$R_{eco}$estimate was comparable to the above-canopy flux ($F_{ac}$) from eddy covariance during defined sustained high turbulence conditions (when presumably$F_{ac} = R_{eco}$) of 8.4 (95% CI = 7.5-9.4). Multiple regression analysis demonstrated that ~50% of the nighttime variability in$F_{ac}$was accounted for by friction velocity (u*, a measure of turbulence) variables. After accounting for u* variability, mean$F_{ac}$varied significantly with seasonal and daily changes in precipitation. A seasonal increase in precipitation resulted in a decrease in$F_{ac}$, similar to our soil respiration response to moisture. The effect of daily changes in precipitation was complex: precipitation after a dry period resulted in a large increase in$F_{ac}$, whereas additional precipitation after a rainy period had little effect. This response was similar to that of surface litter (coarse and fine), where respiration is greatly reduced when moisture is limiting, but increases markedly and quickly saturates with an increase in moisture.
Previous studies have demonstrated that muscle mechanoreflex and metaboreflex controls are altered in heart failure (HF), which seems to be due to changes in cyclooxygenase (COX) pathway and changes ...in receptors on afferent neurons, including transient receptor potential vanilloid type-1 (TRPV1) and cannabinoid receptor type-1 (CB1). The purpose of the present study was to test the hypotheses: 1) exercise training (ET) alters the muscle metaboreflex and mechanoreflex control of muscle sympathetic nerve activity (MSNA) in HF patients. 2) The alteration in metaboreflex control is accompanied by increased expression of TRPV1 and CB1 receptors in skeletal muscle. 3) The alteration in mechanoreflex control is accompanied by COX-2 pathway in skeletal muscle. Thirty-four consecutive HF patients with ejection fractions <40% were randomized to untrained (n = 17; 54 ± 2 yr) or exercise-trained (n = 17; 56 ± 2 yr) groups. MSNA was recorded by microneurography. Mechanoreceptors were activated by passive exercise and metaboreceptors by postexercise circulatory arrest (PECA). COX-2 pathway, TRPV1, and CB1 receptors were measured in muscle biopsies. Following ET, resting MSNA was decreased compared with untrained group. During PECA (metaboreflex), MSNA responses were increased, which was accompanied by the expression of TRPV1 and CB1 receptors. During passive exercise (mechanoreflex), MSNA responses were decreased, which was accompanied by decreased expression of COX-2, prostaglandin-E2 receptor-4, and thromboxane-A2 receptor and by decreased in muscle inflammation, as indicated by increased miRNA-146 levels and the stable NF-κB/IκB-α ratio. In conclusion, ET alters muscle metaboreflex and mechanoreflex control of MSNA in HF patients. This alteration with ET is accompanied by alteration in TRPV1 and CB1 expression and COX-2 pathway and inflammation in skeletal muscle.
Obesity is directly connected to lifestyle and has been associated with DNA methylation changes that may cause alterations in the adipogenesis and lipid storage processes contributing to the ...development of the disease. We demonstrate a complete protocol from selection to epigenetic data analysis of patients with and without obesity. All steps from the protocol were tested and validated in a pilot study. 32 women participated in the study, in which 15 individuals were classified with obesity according to Body Mass Index (BMI) (45.1 ± 5.4 kg/m
); and 17 individuals were classified without obesity according to BMI (22.6 ± 1.8 kg/m
). In the group with obesity, 564 CpG sites related to fat mass were identified by linear regression analysis. The CpG sites were in the promoter regions. The differential analysis found 470 CpGs hypomethylated and 94 hypermethylated sites in individuals with obesity. The most hypomethylated enriched pathwayswere in the RUNX, WNT signaling, and response to hypoxia. The hypermethylated pathways were related to insulin secretion, glucagon signaling, and Ca
. We conclude that the protocol effectively identified DNA methylation patterns and trait-related DNA methylation. These patterns could be associated with altered gene expression, affecting adipogenesis and lipid storage. Our results confirmed that an obesogenic lifestyle could promote epigenetic changes in human DNA.
Sympathetic hyperactivation and baroreflex dysfunction are hallmarks of heart failure with reduced ejection fraction (HFrEF). However, it is unknown whether the progressive loss of phasic activity of ...sympathetic nerve bursts is associated with baroreflex dysfunction in HFrEF patients. Therefore, we investigated the association between the oscillatory pattern of muscle sympathetic nerve activity (LF
MSNA
/HF
MSNA
) and the gain and coupling of the sympathetic baroreflex function in HFrEF patients. In a sample of 139 HFrEF patients, two groups were selected according to the level of LF
MSNA
/HF
MSNA
index: (1) Lower LF
MSNA
/HF
MSNA
(lower terciles,
n
= 46, aged 53 ± 1 y) and (2) Higher LF
MSNA
/HF
MSNA
(upper terciles,
n
= 47, aged 52 ± 2 y). Heart rate (ECG), arterial pressure (oscillometric method), and muscle sympathetic nerve activity (microneurography) were recorded for 10 min in patients while resting. Spectral analysis of muscle sympathetic nerve activity was conducted to assess the LF
MSNA
/HF
MSNA
, and cross-spectral analysis between diastolic arterial pressure, and muscle sympathetic nerve activity was conducted to assess the sympathetic baroreflex function. HFrEF patients with lower LF
MSNA
/HF
MSNA
had reduced left ventricular ejection fraction (26 ± 1 vs. 29 ± 1%,
P
= 0.03), gain (0.15 ± 0.03 vs. 0.30 ± 0.04 a.u./mmHg,
P
< 0.001) and coupling of sympathetic baroreflex function (0.26 ± 0.03 vs. 0.56 ± 0.04%,
P
< 0.001) and increased muscle sympathetic nerve activity (48 ± 2 vs. 41 ± 2 bursts/min,
P
< 0.01) and heart rate (71 ± 2 vs. 61 ± 2 bpm,
P
< 0.001) compared with HFrEF patients with higher LF
MSNA
/HF
MSNA
. Further analysis showed an association between the LF
MSNA
/HF
MSNA
with coupling of sympathetic baroreflex function (
R
= 0.56,
P
< 0.001) and left ventricular ejection fraction (
R
= 0.23,
P
= 0.02). In conclusion, there is a direct association between LF
MSNA
/HF
MSNA
and sympathetic baroreflex function and muscle sympathetic nerve activity in HFrEF patients. This finding has clinical implications, because left ventricular ejection fraction is less in the HFrEF patients with lower LF
MSNA
/HF
MSNA
.
Background
We investigated the effects of muscle functional electrical stimulation on muscle sympathetic nerve activity and muscle blood flow, and, in addition, exercise tolerance in hospitalised ...patients for stabilisation of heart failure.
Methods
Thirty patients hospitalised for treatment of decompensated heart failure, class IV New York Heart Association and ejection fraction ≤ 30% were consecutively randomly assigned into two groups: functional electrical stimulation (n = 15; 54 ± 2 years) and control (n = 15; 49 ± 2 years). Muscle sympathetic nerve activity was directly recorded via microneurography and blood flow by venous occlusion plethysmography. Heart rate and blood pressure were evaluated on a beat-to-beat basis (Finometer), exercise tolerance by 6-minute walk test, quadriceps muscle strength by a dynamometer and quality of life by Minnesota questionnaire. Functional electrical stimulation consisted of stimulating the lower limbs at 10 Hz frequency, 150 ms pulse width and 70 mA intensity for 60 minutes/day for 8–10 consecutive days. The control group underwent electrical stimulation at an intensity of < 20 mA.
Results
Baseline characteristics were similar between groups, except age that was higher and C-reactive protein and forearm blood flow that were smaller in the functional electrical stimulation group. Functional electrical stimulation significantly decreased muscle sympathetic nerve activity and increased muscle blood flow and muscle strength. No changes were found in the control group. Walking distance and quality of life increased in both groups. However, these changes were greater in the functional electrical stimulation group.
Conclusion
Functional electrical stimulation improves muscle sympathetic nerve activity and vasoconstriction and increases exercise tolerance, muscle strength and quality of life in hospitalised heart failure patients. These findings suggest that functional electrical stimulation may be useful to hospitalised patients with decompensated chronic heart failure.
Heart failure (HF) is characterized by decreased exercise capacity, attributable to neurocirculatory and skeletal muscle factors. Cardiac resynchronization therapy (CRT) and exercise training have ...each been shown to decrease muscle sympathetic nerve activity (MSNA) and increase exercise capacity in patients with HF. We hypothesized that exercise training in the setting of CRT would further reduce MSNA and vasoconstriction and would increase Ca
-handling gene expression in skeletal muscle in patients with chronic systolic HF. Thirty patients with HF, ejection fraction <35% and CRT for 1 mo, were randomized into two groups: exercise-trained (ET, n = 14) and untrained (NoET, n = 16) groups. The following parameters were compared at baseline and after 4 mo in each group: V̇o
, MSNA (microneurography), forearm blood flow, and Ca
-handling gene expression in vastus lateralis muscle. After 4 mo, exercise duration and V̇o
were significantly increased in the ET group (P = 0.04 and P = 0.01, respectively), but not in the NoET group. MSNA was significantly reduced in the ET (P = 0.001), but not in NoET, group. Similarly, forearm vascular conductance significantly increased in the ET (P = 0.0004), but not in the NoET, group. The expression of the Na
/Ca
exchanger (P = 0.01) was increased, and ryanodine receptor expression was preserved in ET compared with NoET. In conclusion, the exercise training in the setting of CRT improves exercise tolerance and neurovascular control and alters Ca
-handling gene expression in the skeletal muscle of patients with systolic HF. These findings highlight the importance of including exercise training in the treatment of patients with HF even following CRT.
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