Insights into the dual cleavage activity of the GH16 laminarinase enzyme class on ß-1,3 and ß-1,4 glycosidic bonds.

Glycoside hydrolases (GHs) are involved in the degradation of a wide diversity of carbohydrates and present several biotechnological applications. Many GH families are composed of enzymes with a single well-defined specificity. In contrast, enzymes from the GH16 family can act on a range of different polysaccharides, including ß-glucans and galactans. SCLam, a GH16 member derived from a soil metagenome, an endo-ß-1,3(4)-glucanase (EC 3.2.1.6), can cleave both ß-1,3 and ß-1,4 glycosidic bonds in glucans, such as laminarin, barley ß-glucan, and cello-oligosaccharides. A similar cleavage pattern was previously reported for other GH16 family members. However, the molecular mechanisms for this dual cleavage activity on (1,3)- and (1,4)-ß-D-glycosidic bonds by laminarinases have not been elucidated. In this sense, we determined the X-ray structure of a presumably inactive form of SCLam cocrystallized with different oligosaccharides. The solved structures revealed general bound products that are formed owing to residual activities of hydrolysis and transglycosylation. Biochemical and biophysical analyses and molecular dynamics simulations help to rationalize differences in activity toward different substrates. Our results depicted a bulky aromatic residue near the catalytic site critical to select the preferable configuration of glycosidic bonds in the binding cleft. Altogether, these data contribute to understanding the structural basis of recognition and hydrolysis of ß-1,3 and ß-1,4 glycosidic linkages of the laminarinase enzyme class, which is valuable for future studies on the GH16 family members and applications related to biomass conversion into feedstocks and bioproducts.

Recombinant expression, purification and characterization of an active bacterial feruloyl-CoA synthase with potential for application in vanillin production.

The ferulic acid (FA) represents a high-value molecule with applications in the cosmetic and pharmaceutical industries. This aromatic molecule is derived from lignin and can be enzymatically converted in other commercially interesting molecules, such as vanillin and bioplastics. This process starts with a common step of FA activation via CoA-thioesterification, catalyzed by feruloyl-CoA synthetases. Therefore, here, we report the successfully expression, purification as well as the initial structural and biochemical characterization of a stable, correctly folded, and catalytically active bacterial feruloyl-CoA synthase (here named FCS3) isolated from a lignin-degrading microbial consortium. The purification of recombinant FCS3 to near homogeneity was achieved using affinity chromatography. The FCS3 structure is composed of a mixture of α and ß secondary structures and most likely forms stable homodimers in solution. The FCS3 presented a notable structural stability at alkaline pH values and it was able to convert FA and coenzyme A (CoA) into feruloyl-CoA complex at room temperature. This study should provide a useful basis for future biotechnological applications of FCS3, especially in the field of conversion of lignin-derived FA into high value compounds.

Applying biochemical and structural characterization of hydroxycinnamate catabolic enzymes from soil metagenome for lignin valorization strategies.

The biocatalytic production of fuels and chemicals from plant biomass represents an attractive alternative to fossil fuel-based refineries. In this context, the mining and characterization of novel biocatalysts can promote disruptive innovation opportunities in the field of lignocellulose conversion and valorization. In the present work, we conducted the biochemical and structural characterization of two novel hydroxycinnamic acid catabolic enzymes, isolated from a lignin-degrading microbial consortium, a feruloyl-CoA synthetase, and a feruloyl-CoA hydratase-lyase, named LM-FCS2 and LM-FCHL2, respectively. Besides establishing the homology model structures for novel FCS and FCHL members with unique characteristics, the enzymes presented interesting biochemical features: LM-FCS2 showed stability in alkaline pHs and was able to convert a wide array of p-hydroxycinnamic acids to their respective CoA-thioesters, including sinapic acid; LM-FCHL2 efficiently converted feruloyl-CoA and p-coumaroyl-CoA into vanillin and 4-hydroxybenzaldehyde, respectively, and could produce vanillin directly from ferulic acid. The coupled reaction of LM-FCS2 and LM-FCHL2 produced vanillin, not only from commercial ferulic acid but also from a crude lignocellulosic hydrolysate. Collectively, this work illuminates the structure and function of two critical enzymes involved in converting ferulic acid into high-value molecules, thus providing valuable concepts applied to the development of plant biomass biorefineries. KEY POINTS: • Comprehensive characterization of feruloyl-CoA synthetase from metagenomic origin. • Novel low-resolution structures of hydroxycinnamate catabolic enzymes. • Production of vanillin via enzymatic reaction using lignocellulosic hydrolysates.

The Physical Capacity of Rowing Athletes Cannot Reverse the Influence of Age on Heart Rate Variability during Orthostatic Stress.

The current study was undertaken to test the hypothesis that the high physical capacity of rowing athletes may not reverse the influence of age on cardiac autonomic control decline estimated by heart rate variability (HRV). Forty-four male subjects divided in four groups: 11 young athletes (YA; 18 ±1 year), 11 young non-athletes (YNA; 20 ±1 year), 11 middle age athletes (MAA; 43 ±6 years) and 11 middle age non-athletes (MNA; 44 ±8 years) participated in the study. Heart rate (HR) was recorded beat-by-beat for 10 minutes in supine (SUP) and 10 min in orthostatic (ORT) positions. HRV was analyzed in the frequency domain to obtain the spectral power in the high (HF) and low frequency (LF) bands, and the changes to ORT (%∆HRV) were calculated (ORT - SUP / SUP). During SUP, HF was lower in MNA and MA compared to YA and YNA, while LF was lower in MNA than YA. For %ΔHRV, %ΔHF was higher in YA than YNA, MA and MNA. The %ΔLF was not different among groups. In conclusion, aging seems to overcome the influence of physical fitness on neural regulation of the heart, as highlighted by the HRV response to active standing.

IVIA - Ibero-American VLBI Initiative -Progress on the Brazilian side.

IVIA is a joint initiative of at least 8 Latin-American countries plus Portugal and Spain to make good use of large telecommunications antennas that are out of service in these countries, because most international communications are now using submarine cables. The first step will be to refurbish the antennas and then to start doing single dish observations of radiosources. In a second step the antennas will be equipped with VLBI (Very Long Base Interferometry) equipment, to establish a VLBI network. This project will be able to effectively promote scientific integration in Ibero-America. The work is starting in several countries; here we present several scientific cases for the use of the antennas, and we report on the first Brasilian activities.

Positive Pressure Ventilation Improves Exercise Performance and Attenuates the Fall of Postexercise Inspiratory Muscular Strength in Rower Athletes.

ABSTRACT: Gonçalves, TR and Soares, PP. Positive pressure ventilation improves exercise performance and attenuates the fall of postexercise inspiratory muscular strength in rower athletes. J Strength Cond Res 35(1): 253-259, 2021-Positive pressure ventilation (PPV) can increase exercise performance in cyclists, but its effects are unclear in other exercise modes, especially those using large muscle mass. The aim of this study was to compare the exercise performance and postexercise inspiratory muscles' strength with and without PPV (NO-PPV) during rowing. Nine male rowers (19 ± 1 year) participated in 3 experimental days (M1, M2, and M3) separated by 1 week. In M1, rowers performed a 2,000-m test (2k) on a rowing ergometer to obtain average power (W2k). In M2 and M3, the rowers performed 4 minutes' workouts at 55, 65, 75, and 85% W2k, respectively, separated by 1 minute of recovery, with PPV and NO-PPV application in randomized order. Blood lactate (La) was measured during intervals. After submaximal exercises, with 10 minutes of "cool down," the rowers performed a maximal performance test of 4 minutes (4-minute all-out rowing). Traveled distance was computed and correlated with maximal inspiratory pressure (MIP) changes from pretest to posttest (∆). Positive pressure ventilation application increased the traveled distance in relation to NO-PPV exercise (1,210.7 ± 45.5 vs. 1,199.8 ± 43.4 m, p ≤ 0.05). The ∆MIP (cmH2O) was lower in PPV as compared to NO-PPV exercise (-19.1 ± 10.2 vs. -26.3 ± 7.9 cmH2O, p ≤ 0.05). The [La] showed no significant difference between PPV and NO-PPV exercises (p > 0.05). Therefore, the PPV during whole-body rowing exercise improved the exercise performance and attenuated the inspiratory postexercise fatigue. These findings suggest that inspiratory muscles' strength plays a role during high-intensity exercise with large muscle mass.

Effects of Different Periodization Strategies of Combined Aerobic and Strength Training on Heart Rate Variability in Older Women.

ABSTRACT: Rodrigues, JAL, Santos, BC, Medeiros, LH, Gonçalves, TCP, and Júnior, CRB. Effects of different periodization strategies of combined aerobic and strength training on heart rate variability in older women. J Strength Cond Res 35(7): 2033-2039, 2021-The preservation of autonomic function has been proposed to be a key determinant of health and longevity. Periodization in combined training (CT) (strength plus aerobic exercise in the same session) might improve autonomic modulation. However, the specific influences of nonperiodized (NP), flexible nonlinear periodized (FNLP), and nonlinear periodized (NLP) strategies of CT on heart rate variability (HRV) are currently unknown. Therefore, we investigated the effects of NP, FNLP, and NLP strategies of CT on HRV in physically active women. In total, 54 physically active older women (61.6 ± 6.3 years) previously engaged in a regular exercise training were randomly allocated into 3 groups: NP, FNLP, and NLP. All the subjects performed 12 weeks of training, 3 times per week, with the sessions divided into aerobic (bicycle or treadmill) and strength exercises. Before and after the exercise training, we examined anthropometric, body composition, and HRV measures (low-frequency [LF], high-frequency [HF], LF/HF, and root mean square successive difference of RR intervals [RMSSD]) during rest, a maximum exercise test, and recovery post-test. Mixed-model measures were used, and statistical significance was set at α = 0.05. The waist circumference reduced only in the NP group (∆ = -2.01%). The RMSSD increased in the NLP (∆ = 76.5%) and LF/HF ratio increased in the FNLP (∆ = 34.51%) during the rest period. There were no differences during the exercise test and recovery after test for LF, HF, LF/HF, or RMSSD. In active women, nonlinear periodization strategies of CT improved one of the cardiovascular health outcomes because HRV is a direct predictor of cardiovascular risk.

Colour Me Blue: The History and the Biotechnological Potential of Pyocyanin.

Pyocyanin was the first natural phenazine described. The molecule is synthesized by about 95% of the strains of Pseudomonas aeruginosa. From discovery up to now, pyocyanin has been characterised by a very rich and avant-garde history, which includes its use in antimicrobial therapy, even before the discovery of penicillin opened the era of antibiotic therapy, as well as its use in electric current generation. Exhibiting an exuberant blue colour and being easy to obtain, this pigment is the subject of the present review, aiming to narrate its history as well as to unveil its mechanisms and suggest new horizons for applications in different areas of engineering, biology and biotechnology.

Functional characterization of a novel thermophilic exo-arabinanase from Thermothielavioides terrestris.

Arabinanases from glycoside hydrolase family GH93 are enzymes with exo-activity that hydrolyze the α-1,5 bonds between arabinose residues present on arabinan. Currently, several initiatives aiming to use byproducts rich in arabinan such as pectin and sugar beet pulp as raw material to produce various compounds of interest are being developed. However, it is necessary to use robust enzymes that have an optimal performance under pH and temperature conditions used in the industrial processes. In this work, the first GH93 from the thermophilic fungus Thermothielavioides terrestris (Abn93T) was heterologously expressed in Aspergillus nidulans, purified and biochemically characterized. The enzyme is a thermophilic glycoprotein (optimum activity at 70 °C) with prolonged stability in acid pHs (4.0 to 6.5). The presence of glycosylation affected slightly the hydrolytic capacity of the enzyme, which was further increased by 34% in the presence of 1 mM CoCl2. Small-angle X-ray scattering results show that Abn93T is a globular-like-shaped protein with a slight bulge at one end. The hydrolytic mechanism of the enzyme was elucidated using capillary zone electrophoresis and molecular docking calculations. Abn93T has an ability to produce (in synergism with arabinofuranosidases) arabinose and arabinobiose from sugar beet arabinan, which can be explored as fermentable sugars and prebiotics. KEY POINTS: • Thermophilic exo-arabinanase from family GH93 • Molecular basis of arabinan depolymerization.

ß2 adrenergic interaction and cardiac autonomic function: effects of aerobic training in overweight/obese individuals.

PURPOSE: To verify the influence of different volumes and intensities of aerobic exercise on cardiac autonomic function (CAF) through heart rate variability (HRV) analysis as well the influence of ß2 adrenergic receptor (ADRB2) variants in overweight/obese individuals. METHODS: 70 physically inactive adults were randomly allocated into the following 16-week training: 1-high-intensity interval training (HIIT) (n = 25, 1 × 4 min bout at 85-95%HR peak, 3×/week), 4-HIIT (n = 26, 4 × 4 min bouts at 85-95%HR peak, interspersed with 3 min of recovery at 50-70%HR peak, 3×/week), and moderate continuous training (MCT) (n = 19, 30 min at 60-70%HR peak, 5×/week). Before and after the exercise training, anthropometric, BP, cardiorespiratory fitness, and HRV measures were evaluated. R-R intervals recorded for 10 min in a supine position at pre- and post-intervention were used to analyze HRV in the plot-Poincare indexes (SD1, SD2), and frequency-domain (LF, HF, LF/HF). Full blood samples were used for genotyping. RESULTS: 4-HIIT and MCT showed positive outcomes for almost all variables while 1-HIIT had a positive influence only on SBP and SD2 index. No associations were observed between isolated ADRB2 variants and changes in HRV. In the analysis of the interaction genotypes, all groups responded positively for the SD1 index of HRV and only the H1 (GG and CC) and H2 (GG and CG + GG) groups presented increases in the RMSSD index. Furthermore, there was an increase in the LF index only in the H3 (CC and AA + AG) and H4 (AA + AG and CG + GG) groups. CONCLUSIONS: ADRB2 variants and aerobic exercise training are important interacting variables to improve autonomic function and other health variables outcomes in overweight or obese individuals.

Multicomponent Training Changes Blood Pressure and Redox Status in Older Women: Influence of ß2 Adrenergic Receptor Haplotypes.

The ß2 adrenergic receptor (ß2-AR) plays an important role in vascular smooth muscle. However, the interaction between Arg16Gly and Gln27Glu ß2-AR polymorphisms, and exercise training has not yet been established. This study evaluated the influence of these ß2-AR polymorphisms on body composition, aerobic capacity, blood pressure, lipid profile, nitric oxide, and redox status at baseline and in response to an exercise program in women aged 50-79 years. Genotype and haplotypes were analyzed in association with the previously mentioned variables before and after the multicomponent training (12 weeks, 2 sessions/week, 90 min/session, and exercise intensity between 13 and 15 on the Borg scale). Individuals who carry ß2-AR Arg16Arg/Gln27Gln genotypes presented more improvements in blood pressure, body composition, aerobic capacity, and redox status in response to a multicomponent training program compared with individuals who do not carry this haplotype. In some years, the genetic profile may be used to predict which exercise program can induce more health benefits for each person.

Inspiratory muscle training improves physical performance and cardiac autonomic modulation in older women.

PURPOSE: Aging impairs the autonomic balance reducing the vagal and increasing the sympathetic components of heart rate variability (HRV) and this could be associated with a decline in physical capacity. Inspiratory muscle training (IMT) is a possible tool to attenuate this physical capacity decline in older women. The aim of this study was to investigate the influence of IMT in the older women on physical capacity and autonomic cardiac modulation at rest and post exercise. METHODS: 20 female participants 60-72 years old were randomly allocated in two groups. One group underwent IMT set at 50% of maximum inspiratory pressure (MIP), every day for 4 weeks (IMT-group). The placebo group performed the same training procedure but with a minimal resistance (5% MIP; PLA-group). Every week, the IMT load was readjusted and the HRV evaluated at rest. The six-minute walk test (6MWT) was performed once pre and post IMT-intervention. The IMT-group and PLA-group performed the same test and intervention procedures. RESULTS: After a 5 weeks intervention, the MIP had significantly improved in the IMT-group but not in the PLA-group (p < 0.01; es = 1.17). The high frequency power of the HRV spectrum had already improved by the second week (p < 0.01; es = 1.13) and remained elevated until the last week of intervention (p < 0.01; es = 1.43). The same positive results were described in 6MWT distance (p = 0.04; es = 0.39) and the change (∆) of heart rate recovery (HRR) from 1 min (p = 0.02; es = 0.68). CONCLUSION: IMT increases HRV, improves 6MWT distance and HRR.

Xyloglucan breakdown by endo-xyloglucanase family 74 from Aspergillus fumigatus.

Xyloglucan is the most abundant hemicellulose in primary walls of spermatophytes except for grasses. Xyloglucan-degrading enzymes are important in lignocellulosic biomass hydrolysis because they remove xyloglucan, which is abundant in monocot-derived biomass. Fungal genomes encode numerous xyloglucanase genes, belonging to at least six glycoside hydrolase (GH) families. GH74 endo-xyloglucanases cleave xyloglucan backbones with unsubstituted glucose at the -1 subsite or prefer xylosyl-substituted residues in the -1 subsite. In this work, 137 GH74-related genes were detected by examining 293 Eurotiomycete genomes and Ascomycete fungi contained one or no GH74 xyloglucanase gene per genome. Another interesting feature is that the triad of tryptophan residues along the catalytic cleft was found to be widely conserved among Ascomycetes. The GH74 from Aspergillus fumigatus (AfXEG74) was chosen as an example to conduct comprehensive biochemical studies to determine the catalytic mechanism. AfXEG74 has no CBM and cleaves the xyloglucan backbone between the unsubstituted glucose and xylose-substituted glucose at specific positions, along the XX motif when linked to regions deprived of galactosyl branches. It resembles an endo-processive activity, which after initial random hydrolysis releases xyloglucan-oligosaccharides as major reaction products. This work provides insights on phylogenetic diversity and catalytic mechanism of GH74 xyloglucanases from Ascomycete fungi.

ArtinM Mediates Murine T Cell Activation and Induces Cell Death in Jurkat Human Leukemic T Cells.

The recognition of cell surface glycans by lectins may be critical for the innate and adaptive immune responses. ArtinM, a d-mannose-binding lectin from Artocarpus heterophyllus, activates antigen-presenting cells by recognizing TLR2 N-glycans and induces Th1 immunity. We recently demonstrated that ArtinM stimulated CD4⁺ T cells to produce proinflammatory cytokines. Here, we further studied the effects of ArtinM on adaptive immune cells. We showed that ArtinM activates murine CD4⁺ and CD8⁺ T cells, augmenting their positivity for CD25, CD69, and CD95 and showed higher interleukin (IL)-2 and interferon (IFN)-γ production. The CD4⁺ T cells exhibited increased T-bet expression in response to ArtinM, and IL-2 production by CD4⁺ and CD8⁺ T cells depended on the recognition of CD3εγ-chain glycans by ArtinM. The ArtinM effect on aberrantly-glycosylated neoplastic lymphocytes was studied in Jurkat T cells, in which ArtinM induced IL-2, IFN-γ, and IL-1ß production, but decreased cell viability and growth. A higher frequency of AnnexinV- and propidium iodide-stained cells demonstrated the induction of Jurkat T cells apoptosis by ArtinM, and this apoptotic response was reduced by caspases and protein tyrosine kinase inhibitors. The ArtinM effects on murine T cells corroborated with the immunomodulatory property of lectin, whereas the promotion of Jurkat T cells apoptosis may reflect a potential applicability of ArtinM in novel strategies for treating lymphocytic leukemia.

Molecular basis of substrate recognition and specificity revealed in family 12 glycoside hydrolases.

Fungal GH12 enzymes are classified as xyloglucanases when they specifically target xyloglucans, or promiscuous endoglucanases when they exhibit catalytic activity against xyloglucan and ß-glucan chains. Several structural and functional studies involving GH12 enzymes tried to explain the main patterns of xyloglucan activity, but what really determines xyloglucanase specificity remains elusive. Here, three fungal GH12 enzymes from Aspergillus clavatus (AclaXegA), A. zonatus (AspzoGH12), and A. terreus (AtEglD) were studied to unveil the molecular basis for substrate specificity. Using functional assays, site-directed mutagenesis, and molecular dynamics simulations, we demonstrated that three main regions are responsible for substrate selectivity: (i) the YSG group in loop 1; (ii) the SST group in loop 2; and (iii) loop A3-B3 and neighboring residues. Functional assays and sequence alignment showed that while AclaXegA is specific to xyloglucan, AtEglD cleaves ß-glucan, and xyloglucan. However, AspzoGH12 was also shown to be promiscuous contrarily to a sequence alignment-based prediction. We find that residues Y111 and R93 in AtEglD harbor the substrate in an adequate orientation for hydrolysis in the catalytic cleft entrance and that residues Y19 in AclaXegA and Y30 in AspzoGH12 partially compensate the absence of the YSG segment, typically found in promiscuous enzymes. The results point out the multiple structural factors underlying the substrate specificity of GH12 enzymes. Biotechnol. Bioeng. 2016;113: 2577-2586. © 2016 Wiley Periodicals, Inc.

Correlation between cardiac autonomic modulation in response to orthostatic stress and indicators of quality of life, physical capacity, and physical activity in healthy individuals.

Increased heart rate variability (HRV) at rest is frequently associated to maximal oxygen uptake (VO2max), physical activity, and markers of quality of life (QoL). However, the HRV has not been observed during physical exercise or orthostatic (ORT) challenge. This study investigated the associations of HRV changes (ΔHRV) from rest at supine (SUP) to ORT positions with (VO2max), physical activity level, and QoL in young adults. Cardiac autonomic modulation was assessed by spectral analysis of R-R time series measured from SUP to ORT positions in 15 healthy volunteers (26 ± 7 years). Questionnaires were applied for evaluation of QoL (SF-36 score), to estimate (VO2max), and to quantify physical activity (Baecke Sport Score). All HRV indices at SUP, but not ORT, strongly correlated to QoL, estimated (VO2max), and physical activity. The ΔHRV from SUP to ORT showed significant correlations with all questionnaire scores (r = 0.52-0.61 for low frequency and r = -0.61 to -0.65 for high frequency, p ≤ 0.05). Higher vagal activity at rest and greater changes in adrenergic and parasympathetic modulation from SUP to ORT were detected in the volunteers exhibiting higher scores of QoL, estimated (VO2max), and physical activity. Taken together, the level of neural adaptations from resting SUP position to active standing, and physical activity and QoL questionnaires seem to be a simple approach to understand the physiological and lifestyle adaptations to exercise that may be applied to a large sample of subjects in almost any sports facilities at a low cost.

Combined remote ischemic perconditioning and local postconditioning on liver ischemia-reperfusion injury.

BACKGROUND: Remote ischemic perconditioning (rPER) is the newest technique described to mitigate ischemia and reperfusion (IR) injury. Local postconditioning (POS) is also an effective technique for this purpose. It is uncertain if adding local POS to rPER provides superior liver protection, so we tested this hypothesis. MATERIALS AND METHODS: Twenty five Wistar rats were assigned into five groups: sham, IR, POS, rPER, and rPER + POS. Animals were subjected to liver ischemia for 60 min. POS consisted of four cycles of 5-min liver perfusion followed by 5-min liver ischemia (40 min total) after the major ischemic period. rPER consisted of four cycles of 5-min hindlimb ischemia followed by 5 min hindlimb perfusion contemporaneously to major liver ischemic period, during its last 40 min. After 2 h, median and left lobes were harvested for malondialdehyde and Trolox equivalent antioxidant capacity (TEAC) measurement, and blood for the measurement of serum transaminases. RESULTS: All tissue conditioning techniques were able to reduce transaminases serum levels, having no differences among them. All tissue conditioning techniques were able to reduce hepatic tissue MDA level; however, only rPER + POS had higher values than SHAM. All tissue conditioning techniques also enhanced TEAC; however, only POS had lower TEAC than SHAM. CONCLUSIONS: rPER appears as the most promising technique to avoid IR injury. This technique reduced oxidative stress of cell membranes and lowered transaminases serum level. There was no additive protection when POS and rPER were held together.

Development of hemicellulolytic enzyme mixtures for plant biomass deconstruction on target biotechnological applications.

An essential step in the conversion of lignocellulosic biomass to ethanol and other biorefinery products is conversion of cell wall polysaccharides into fermentable sugars by enzymatic hydrolysis. The objective of the present study was to understand the mode of action of hemicellulolytic enzyme mixtures for pretreated sugarcane bagasse (PSB) deconstruction and wheat arabinoxylan (WA) hydrolysis on target biotechnological applications. In this study, five hemicellulolytic enzymes-two endo-1,4-xylanases (GH10 and GH11), two α-L-arabinofuranosidases (GH51 and GH54), and one ß-xylosidase (GH43)-were submitted to combinatorial assays using the experimental design strategy, in order to analyze synergistic and antagonistic effects of enzyme interactions on biomass degradation. The xylooligosaccharides (XOSs) released from hydrolysis were analyzed by capillary electrophoresis and quantified by high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Based on this analysis, it was possible to define which enzymatic combinations favor xylose (X1) or XOS production and thus enable the development of target biotechnological applications. Our results demonstrate that if the objective is X1 production from WA, the best enzymatic combination is GH11 + GH54 + GH43, and for xylobiose (X2) production from WA, it is best to combine GH11 + GH51. However, if the goal is to produce XOS, the five enzymes used in WA hydrolysis are important, but for PSB hydrolysis, only GH11 is sufficient. If the final objective is bioethanol production, GH11 is responsible for hydrolyzing 64.3 % of hemicellulose from PSB. This work provides a basis for further studies on enzymatic mechanisms for XOS production, and the development of more efficient and less expensive enzymatic mixtures, targeting commercially viable lignocellulosic ethanol production and other biorefinery products.

The Relationship between Inspiratory Muscle Strength and Cycling Performance: Insights from Hypoxia and Inspiratory Muscle Warm-Up.

Hypoxia increases inspiratory muscle work and consequently contributes to a reduction in exercise performance. We evaluate the effects of inspiratory muscle warm-up (IMW) on a 10 km cycling time trial in normoxia (NOR) and hypoxia (HYP). Eight cyclists performed four time trial sessions, two in HYP (FiO2: 0.145) and two in NOR (FiO2: 0.209), of which one was with IMW (set at 40% of maximal inspiratory pressure-MIP) and the other was with the placebo effect (PLA: set at 15% MIP). Time trials were unchanged by IMW (NORIMW: 893.8 ± 31.5 vs. NORPLA: 925.5 ± 51.0 s; HYPIMW: 976.8 ± 34.2 vs. HYPPLA: 1008.3 ± 56.0 s; p > 0.05), while ventilation was higher in HYPIMW (107.7 ± 18.3) than HYPPLA (100.1 ± 18.9 L.min-1; p ≤ 0.05), and SpO2 was lower (HYPIMW: 73 ± 6 vs. HYPPLA: 76 ± 6%; p ≤ 0.05). A post-exercise-induced reduction in inspiratory strength was correlated with exercise elapsed time during IMW sessions (HYPIMW: r = -0.79; p ≤ 0.05; NORIMW: r = -0.70; p ≤ 0.05). IMW did not improve the 10 km time trial performance under normoxia and hypoxia.