AMWEst, a new thermostable and detergent-tolerant esterase retrieved from the Albian aquifer.

A fosmid library was constructed with the metagenomic DNA from the high-temperature sediment-rich water of the Albian aquifer (Algeria). Functional screening of this library was subsequently done looking for genes encoding lipolytic enzymes. We identified a novel gene named AMWEst (1209 base pairs) encoding a protein of 402 amino acids with a predicted molecular weight of 43.44 kDa and conferring esterase activity. AMWEst was successfully overexpressed in the yeast mesophilic host Saccharomyces cerevisiae, and the expression system used proved to be efficient and produced sufficient activity for its biochemical characterization. Multiple sequence alignment indicated that AMWEst contained a conserved pentapeptide motif (Gly120-His121-Ser122-Gln123-Gly124). The optimum pH and temperature of the recombinant esterase AMWEst were 8 and 80 °C, respectively. Additionally, AMWEst showed higher activity towards short carbon substrates and showed maximum activity for p-nitrophenyl hexanoate (C6). Notably, AMWEst has a remarkable thermostability, and the enzyme retains almost maximum activity at 70 °C after incubation for 1 h. Moreover, enzyme activity was enhanced by high concentrations of SDS and Triton X-100 detergents. KEY POINTS: • A novel thermostable esterase has been retrieved through functional metagenomics • The esterase is detergent-tolerant, which is attractive for some applications • The esterase can be expressed in a yeast mesophilic host to enhance its yield.

Effect of a High-Intensity Handball-Specific Fatigue Protocol Focused on the Leg Contralateral to the Throwing Arm on Interlimb Asymmetries.

ABSTRACT: Janicijevic, D, Pérez-Castilla, A, Miras-Moreno, S, Ortega-Becerra, M, Morenas-Aguilar, MD, Smajla, D, Sarabon, N, and García-Ramos, A. Effect of a high-intensity handball-specific fatigue protocol focused on the leg contralateral to the throwing arm on interlimb asymmetries. J Strength Cond Res 37(7): 1382-1389, 2023-This study aimed to elucidate which countermovement jump (CMJ) variant (unilateral or bilateral) is more sensitive to detect the decrement in kinetic CMJ-derived variables of the leg more actively involved in a handball-specific fatigue protocol. Seventeen female handball players (age: 20.6 ± 2.5 years) performed a fatigue protocol consisting of 8 repetitions of the following circuit separated by 10 seconds: 10 m sprint, 180° change of direction with the leg contralateral to the throwing arm, 10 m sprint with ball reception at 7 m, and handball throw preceded by a jump over a 40 cm hurdle with the leg contralateral to the throwing arm. Before and after the fatigue protocol, 6 unilateral CMJs (3 with each leg) and 3 bilateral CMJs were performed on a dual Kistler force platform (model 9260AA6). Bilateral CMJ height was reduced by 5.4% after the fatigue protocol (p < 0.001). However, the fatigue protocol did not promote any significant change in peak force, mean force, and propulsive impulse or in their asymmetry values (17 of 18 comparisons). The decrement of 6.1% during the unilateral CMJ in the propulsive impulse developed by the leg ipsilateral to the throwing arm (less involved in the fatigue protocol) was the only variable that reached statistical significance (p = 0.038). The pre-post fatigue changes in asymmetry values presented negligible correlations between both CMJ variants (rs = 0.01 to -0.19). These results suggest that neither unilateral nor bilateral CMJs are able to detect changes in interlimb asymmetries after a high-intensity handball-specific fatigue protocol.

Bioprospecting for Thermozymes and Characterization of a Novel Lipolytic Thermozyme Belonging to the SGNH/GDSL Family of Hydrolases.

Functional screenings were conducted on two metagenomic libraries from hot springs in order to find novel thermozymes with potential biotechnological applications. These included enzymes acting on plant cell walls such as endoglucanases and exoglucanases, ß-glucosidases, xylanases, and ß-xylosidases, and broad application enzymes such as proteases and lipolytic hydrolases. Of all the enzymes found by this bioprospection, we selected a novel lipolytic enzyme for further characterization. The protein was found to belong to the SGNH/GDSL family of hydrolases. It was purified and its biochemical parameters determined. We found that the enzyme was most active at 60 °C and pH 9 using pNP-laurate as substrate and was highly thermostable. It also showed preference for short-chained substrates and activation with temperature and with certain detergents such as Tween 80. Proteins of this family of hydrolases are relevant for their broad substrate specificity, that coupled with this protein's high temperature optima, broad pH range, and thermostability further highlights its biotechnological potential.

Insights on Microbial Communities Inhabiting Non-Volcanic Hot Springs.

The northwest of Spain has an abundance of non-volcanic hot springs that, until recently, had only been used for thermalism activities. One of such hot springs, Muiño da Veiga, has now been explored using metagenomics to study the microbial community that inhabits these high-temperature circumneutral continental waters. Sequencing of the metagenome allowed the characterization of its composition, diversity, metabolic connections and potential as a source for thermozymes, as well as its ability to assemble MAGs. A diverse microbial community dominated by Bacteria domain members was revealed, particularly from the early-branching Aquificales group. The most abundant genus was Sulfurihydrogenibium, known for its implication in sulfur cycling and for forming mats that enable novel niches. The variety of primary producers with autotrophic pathways (and specifically the sulfur oxidizing pathway) expands the range of available nutrients, and the increase in biomass forms thicker mats, resulting in more available niches and broader microbial diversity. Nonetheless, certain metabolic pathways were attributed to less abundant members of the microbial community, reinforcing the idea that the rare biosphere plays important roles in the network of interactions present in an ecosystem and acts as genetic reservoirs. In addition, three of the assembled MAGs represent novel microbial diversity found in this hot spring. Moreover, the presence of enzymes and microorganisms with possible biotechnological applications was confirmed, including proteases, lipases and cell-wall degrading enzymes, pointing to the potential for the hot spring as a source for thermozymes.

Effects of Cluster Set Configuration on Mechanical Performance and Neuromuscular Activity.

ABSTRACT: Ortega-Becerra, M, Sánchez-Moreno, M, and Pareja-Blanco, F. Effects of cluster set configuration on mechanical performance and neuromuscular activity. J Strength Cond Res 35(2): 310-317, 2021-The aim of this study was to compare the effects of different cluster set (CS) configurations on mechanical performance and electromyography (EMG) activity during the bench press (BP) exercise. Fourteen strength-trained men (age 23.0 ± 2.4 years; height 1.76 ± 0.08 m; body mass 78.3 ± 12.2 kg) performed 3 different protocols in the BP exercise consisting of 3 sets of 12 repetitions at 60% of 1 repetition maximum with interset rests of 2 minutes, differing in the set configuration: (a) traditional sets (TRDs), (b) cluster sets of 4 repetitions (CS4), and (c) cluster sets of 2 repetitions (CS2). Intraset rests of 30 seconds were interposed for CS protocols. The mean propulsive values of force, velocity, and power output were measured for every repetition by synchronizing a linear velocity transducer with a force platform. The root mean square (RMS) and median frequency (MDF) for pectoralis major (PM) and triceps brachii (TB) muscles were also recorded for every repetition. Force, velocity, and power values progressively increased as the number of intraset rests increased (TRD < CS4 < CS2). The CS2 protocol exhibited lower RMS-PM than CS4 and TRD for almost all sets. In addition, TRDs showed significantly lower MDF-TB than CS2 for all sets and lower MDF-TB than CS4 during the third set. In conclusion, more frequent intraset rests were beneficial for maintaining mechanical performance, which may be mediated, from a neuromuscular perspective, by lesser increases in EMG amplitude and attenuated reductions in EMG frequency.

Effects of velocity loss in the bench press exercise on strength gains, neuromuscular adaptations, and muscle hypertrophy.

OBJECTIVE: This study aimed to compare the effects of four velocity-based training (VBT) programs in bench press (BP) between a wide range of velocity loss (VL) thresholds-0% (VL0), 15% (VL15), 25% (VL25), and 50% (VL50)-on strength gains, neuromuscular adaptations, and muscle hypertrophy. METHODS: Sixty-four resistance-trained young men were randomly assigned into four groups (VL0, VL15, VL25, and VL50) that differed in the VL allowed in each set. Subjects followed a VBT program for 8-weeks using the BP exercise. Before and after the VBT program the following tests were performed: (a) cross-sectional area (CSA) measurements of pectoralis major (PM) muscle; (b) maximal isometric test; (c) progressive loading test; and (d) fatigue test. RESULTS: Significant group x time interactions were observed for CSA (P < .01) and peak root mean square in PM (peak RMS-PM, P < .05). VL50 showed significantly greater gains in CSA than VL0 (P < .05). Only the VL15 group showed significant increases in peak RMS-PM (P < .01). Moreover, only VL0 showed significant gains in the early rate of force development (RFD, P = .05), while VL25 and VL50 improved in the late RFD (P ≤ .01-.05). No significant group × time interactions were found for any of the dynamic strength variables analyzed, although all groups showed significant improvements in all these parameters. CONCLUSION: Higher VL thresholds allowed for a greater volume load which maximized muscle hypertrophy, whereas lower VL thresholds evoked positive neuromuscular-related adaptations. No significant differences were found between groups for strength gains, despite the wide differences in the total volume accumulated by each group.

Analysis of the Load-Velocity Relationship in Deadlift Exercise.

The aim of this study was to analyze the relationship between movement velocity and relative load (%1RM) in the deadlift exercise. Fifty men (age = 23.8 ± 3.6 years, body mass = 78.2 ± 8.3 kg, height = 1.78 ± 0.06 m) performed a first evaluation (T1) consisting of a one-repetition maximum (1RM) test. Forty-two subjects performed a second evaluation (T2) after 6 weeks. Mean (MV), mean propulsive (MPV) and peak (PV) velocity measures of the concentric phase were analyzed. Load-velocity relationships were studied by fitting first order equations to the data using loads from 30-100% of 1RM. A comprehensive set of statistics for assessing bias and level of agreement to estimate the 1RM value from the different models was used. Stability of these relationships was assessed using the coefficient of variation (CV) and the intraclass correlation coefficient (ICC). General load-velocity equations provided good adjustments (R2 ~; 0.91-0.93), however individual load-velocity regressions provided better adjustments (R2 ~; 0.97). Individual estimations also showed higher agreement and more regular variation than general equations. Moreover, MPV showed smaller bias than the other velocity parameters (MV and PV). The stability analysis of the load-velocity relationships resulted in ICC values higher than 0.82 and CV lower than 3.0%. Monitoring repetition velocity allows estimation of the %1RM in the deadlift exercise. More accurate predictions of relative load can be obtained when using individualized regression equations instead of general equations.

Optimization of Saccharomyces cerevisiae α-galactosidase production and application in the degradation of raffinose family oligosaccharides.

BACKGROUND: α-Galactosidases are enzymes that act on galactosides present in many vegetables, mainly legumes and cereals, have growing importance with respect to our diet. For this reason, the use of their catalytic activity is of great interest in numerous biotechnological applications, especially those in the food industry directed to the degradation of oligosaccharides derived from raffinose. The aim of this work has been to optimize the recombinant production and further characterization of α-galactosidase of Saccharomyces cerevisiae. RESULTS: The MEL1 gene coding for the α-galactosidase of S. cerevisiae (ScAGal) was cloned and expressed in the S. cerevisiae strain BJ3505. Different constructions were designed to obtain the degree of purification necessary for enzymatic characterization and to improve the productive process of the enzyme. ScAGal has greater specificity for the synthetic substrate p-nitrophenyl-α-D-galactopyranoside than for natural substrates, followed by the natural glycosides, melibiose, raffinose and stachyose; it only acts on locust bean gum after prior treatment with ß-mannosidase. Furthermore, this enzyme strongly resists proteases, and shows remarkable activation in their presence. Hydrolysis of galactose bonds linked to terminal non-reducing mannose residues of synthetic galactomannan-oligosaccharides confirms that ScAGal belongs to the first group of α-galactosidases, according to substrate specificity. Optimization of culture conditions by the statistical model of Response Surface helped to improve the productivity by up to tenfold when the concentration of the carbon source and the aeration of the culture medium was increased, and up to 20 times to extend the cultivation time to 216 h. CONCLUSIONS: ScAGal characteristics and improvement in productivity that have been achieved contribute in making ScAGal a good candidate for application in the elimination of raffinose family oligosaccharides found in many products of the food industry.

Jump height loss as an indicator of fatigue during sprint training.

This study analysed the acute mechanical and metabolic responses to a sprint training session focused on maintaining maximal speed until a given speed loss was reached. Nine male high-level sprinters performed 60 m running sprints up to a 3% in speed loss with 6 min rests between sets. Mechanical responses (countermovement jump (CMJ) height and speed loss) and metabolic responses (blood lactate and ammonia concentrations) were measured pre-exercise and after each set was performed. Jump height loss showed almost perfect relationships with both lactate (r = 0.91) and ammonia (r = 0.91) concentrations. In addition, nearly perfect relationships were observed for each athlete between CMJ height loss and lactate (r = 0.93-0.99) and ammonia (r = 0.94-0.99). Very large correlations were found between speed loss and lactate (r = 0.83), and ammonia (r = 0.86) concentrations. Furthermore, close relationships were observed for each athlete between speed loss and lactate (r = 0.86-0.99), and ammonia (r = 0.88-0.98). These results suggest that the CMJ test may allow more accurate setting of training loads in sprint training sessions, by using an individualised sprint dose based on mechanical and physiological responses rather than a standard fixed number of sprints for all athletes.

Valuation of agro-industrial wastes as substrates for heterologous production of α-galactosidase.

BACKGROUND: The recycling of agro-industrial wastes is at present limited by the availability of efficient and low-cost enzyme cocktails. The use of these materials as culture media to produce the enzymes can contribute to the profitability of the recycling process and to the circular economy. The aim of this work is the construction of a recombinant yeast strain efficient to grow in mixed whey (residue of cheese making) and beet molasses (residue of sugar manufacture) as culture medium, and to produce heterologous α-galactosidase, an enzyme with varied industrial applications and wide market. RESULTS: The gene MEL1, encoding the α-galactosidase of Saccharomyces cerevisiae, was integrated (four copies) in the LAC4 locus of the Kluyveromyces lactis industrial strain GG799. The constructed recombinant strain produces high levels of extracellular α-galactosidase under the control of the LAC4 promoter, inducible by lactose and galactose, and the native MEL1 secretion signal peptide. K. lactis produces natively beta-galactosidase and invertase thus metabolizing the sugars of whey and molasses. A culture medium based on whey and molasses was statistically optimized, and then the cultures scaled-up at laboratory level, thus obtaining 19 U/mL of heterologous α-galactosidase with a productivity of 0.158 U/L h, which is the highest value reported hitherto from a cheap waste-based medium. CONCLUSIONS: A K. lactis recombinant strain was constructed and a sustainable culture medium, based on a mixture of cheese whey and beet molasses, was optimized for high productivity of S. cerevisiae α-galactosidase, thus contributing to the circular economy by producing a heterologous enzyme from two agro-industrial wastes.

Determinant Factors of Physical Performance and Specific Throwing in Handball Players of Different Ages.

Ortega-Becerra, M, Pareja-Blanco, F, Jiménez-Reyes, P, Cuadrado-Peñafiel, V, and González-Badillo, JJ. Determinant factors of physical performance and specific throwing in handball players of different ages. J Strength Cond Res 32(6): 1778-1786, 2018-This study aimed to analyze various fitness qualities in handball players of different ages and to determine the relationships between these parameters and throwing velocity. A total of 44 handball players participated, pooled by age groups: professional (ELITE, n = 13); under-18 (U18, n = 16); under-16 (U16, n = 15). The following tests were completed: 20-m running sprints; countermovement jumps (CMJs); jump squat to determine the load that elicited ∼20 cm jump height (JSLOAD-20 cm); a progressive loading test in full squat and bench press to determine the load that elicited ∼1 m·s (SQ-V1-LOAD and BP-V1-LOAD); and handball throwing (jump throw and 3-step throw). ELITE showed greater performance in almost all sprint distances, CMJ, JSLOAD-20 cm, and bench press strength than U18 and U16. The differences between U18 and U16 were unclear for these variables. ELITE also showed greater (p < 0.001) performance for squat strength and throwing than U18 and U16, and U18 attained greater performance (p ≤ 0.05) for these variables than U16. Throwing performance correlated (p ≤ 0.05) with sprint times (r = -0.31; -0.51) and jump ability (CMJ: r = 0.39; 0.56 and JSLOAD-20 cm: r = 0.57; 0.60). Muscle strength was also associated (p < 0.001) with both types of throw (SQ-V1-LOAD: r = 0.66; 0.76; and BP-V1-LOAD: r = 0.33; 0.70). These results indicate that handball throwing velocity is strongly associated with lower-limb strength, although upper-limb strength, jumping and sprint capacities also play a relevant role in throwing performance, suggesting the need for coaches to include proper strength programs to improve handball players' throwing velocity.

Analysis of Time-Motion and Heart Rate in Elite Male and Female Beach Handball.

Beach handball is a spectacular new team sport; however, scientific knowledge about the demands in beach handball is very low. Consequently, the aim of this study was to analyze the physical demands of elite beach handball players by means of time-motion analysis with GPS technology and physiological response with Heart Rate (HR). Both male (n = 12) and female (n = 12) players from the Spanish Beach Handball National Team were recruited for this study. The sample consisted in four matches of two 10-min periods each. Time-motion analysis was performed through GPS devices (SPI Pro X, 15 Hz, GPSports) with synchronized HR monitoring (Polar Electro, Finland). All parameters were recorded for matches and halves to express overall and time-dependent physical and physiological responses. Total match distance covered by male and female players were 1234.7 ± 192 m and 1118.2 ± 221.8 m, respectively. Female players covered more total distance (p = 0.049, ES = 0.79) and distance walking (p < 0.001, ES = 2.04) in the first half, whereas they covered more distance standing (p = 0.008, ES = 1.05) in the second half at a higher average speed (p < 0.001, ES = 2.28). The number of accelerations distributed over low-, moderate- and high-intensity categories were 43.2 ± 11.6, 9.4 ± 4.9; 0.8 ± 0.9 m/s2 for male players, and 40.3 ± 12.7, 4.3 ± 3.0; 0.1 ± 0.3 m/s2 for female players; equivalent to one body acceleration every 23 s and 27 s, respectively. Finally, male and female players obtained a maximum/mean HR of 173 ± 13 / 137 ± 12 bpm, and 177 ± 13 / 138 ± 18 bpm, with 20.3% and 29.2% of the total time in the anaerobic zone (81 - 90% HRmax), respectively. These results demonstrated that beach handball is a demanding sport, with numerous moderate-to-high intensity displacements, distributed intermittently throughout the game: long periods of low intensity activity interspersed by short bursts of high intensity.

KlGcr1 controls glucose-6-phosphate dehydrogenase activity and responses to H2O2, cadmium and arsenate in Kluyveromyces lactis.

It has been previously reported that Gcr1 differentially controls growth and sugar utilization in Saccharomyces cerevisiae and Kluyveromyces lactis, although the regulatory mechanisms causing activation of glycolytic genes are conserved (Neil et al., 2004). We have found that KlGCR1 deletion diminishes glucose consumption and ethanol production, but increases resistance to oxidative stress caused by H2O2, cadmium and arsenate, glucose 6P dehydrogenase activity, and the NADPH/NADP(+) and GSH/GSSG ratios in K. lactis. The gene KlZWF1 that encodes for glucose 6P dehydrogenase, the first enzyme in the pentose phosphate pathway, is transcriptionally regulated by KlGcr1. The high resistance to oxidative stress observed in the ΔKlgcr1 mutant strain, could be explained as a consequence of an increased flux of glucose through the pentose phosphate pathway. Since mitochondrial respiration decreases in the ΔKlgcr1 mutant (García-Leiro et al., 2010), the reoxidation of the NADPH, produced through the pentose phosphate pathway, has to be achieved by the reduction of other molecules implied in the defense against oxidative stress, like GSSG. The higher GSH/GSSG ratio in the mutant would explain its phenotype of increased resistance to oxidative stress.

Biobutanol from cheese whey.

At present, due to environmental and economic concerns, it is urgent to evolve efficient, clean and secure systems for the production of advanced biofuels from sustainable cheap sources. Biobutanol has proved better characteristics than the more widely used bioethanol, however the main disadvantage of biobutanol is that it is produced in low yield and titer by ABE (acetone-butanol-ethanol) fermentation, this process being not competitive from the economic point of view. In this review we summarize the natural metabolic pathways for biobutanol production by Clostridia and yeasts, together with the metabolic engineering efforts performed up to date with the aim of either enhancing the yield of the natural producer Clostridia or transferring the butanol production ability to other hosts with better attributes for industrial use and facilities for genetic manipulation. Molasses and starch-based feedstocks are main sources for biobutanol production at industrial scale hitherto. We also review herewith (and for the first time up to our knowledge) the research performed for the use of whey, the subproduct of cheese making, as another sustainable source for biobutanol production. This represents a promising alternative that still needs further research. The use of an abundant waste material like cheese whey, that would otherwise be considered an environmental pollutant, for biobutanol production, makes economy of the process more profitable.

Relationships between repeated sprint ability, mechanical parameters, and blood metabolites in professional soccer players.

This study analyzed the acute metabolic and mechanical responses to a specific repeated sprint ability (RSA) test. Eighteen male professional soccer players from a team of the First Division of Spanish National League participated. A 12 × 30-m RSA test with 30-second recovery together with countermovement jump test (CMJ) pre a post RSA test was performed. Mechanical responses (i.e., height performance in CMJ and speed loss) and metabolic responses (i.e., blood lactate and ammonia concentrations) were measured before and after exercise. A related sample t-test was used to analyze CMJ height pre-post changes as well as to compare pre- and post-exercise lactate and ammonia levels. Countermovement jump height loss pre-post session (8%) was significant, and fatigue, measured as CMJ height loss, was strongly correlated to lactate (r = 0.97; p < 0.001) and ammonia (r = 0.92; p < 0.001) for all players. The relationships between the variables studied were determined by calculating the Pearson correlation coefficients. The metabolic stress developed during the effort can be estimated by controlling CMJ because of the high correlation between CMJ and blood lactate and ammonia concentrations. The high correlations found between mechanical (speed and CMJ height losses) and metabolic (lactate and ammonia) measures of fatigue highlight the utility and validity of using CMJ to monitor training load and quantify objectively neuromuscular fatigue during RSA.

Sky1 regulates the expression of sulfur metabolism genes in response to cisplatin.

Cisplatin is commonly used in cancer therapy and yeast cells are also sensitive to this compound. We present a transcriptome analysis discriminating between RNA changes induced by cisplatin treatment, which are dependent on or independent of SKY1 function--a gene whose deletion increases resistance to the drug. Gene expression changes produced by addition of cisplatin to W303 and W303-Δsky1 cells were recorded using DNA microarrays. The data, validated by quantitative PCR, revealed 122 differentially expressed genes: 69 upregulated and 53 downregulated. Among the upregulated genes, those related to sulfur metabolism were over-represented and partially dependent on Sky1. Deletions of MET4 or other genes encoding co-regulators of the expression of sulfur-metabolism-related genes, with the exception of MET28, did not modify the cisplatin sensitivity of yeast cells. One of the genes with the highest cisplatin-induced upregulation was SEO1, encoding a putative permease of sulfur compounds. We also measured the platinum, sulfur and glutathione content in W303, W303-Δsky1 and W303-Δseo1 cells after cisplatin treatment, and integration of the data suggested that these transcriptional changes might represent a cellular response that allowed chelation of cisplatin with sulfur-containing amino acids and also helped DNA repair by stimulating purine biosynthesis. The transcription pattern of stimulation of sulfur-containing amino acids and purine synthesis decreased, or even disappeared, in the W303-Δsky1 strain.

Editorial for Special Issue "Yeasts Biochemistry and Biotechnology".

Yeasts, both Saccharomyces and non-conventional strains, are currently the focus of active research due to their impressive applications in biotechnological bioprocesses, such as being hosts to produce recombinant proteins or main actors of the fermentation industries [...].

Effects of Sand Surface Plyometric and Sprint Training on Physical and Technical Skill Performance in Beach Handball Players.

This study compared the effects of a 6-week combined plyometric and sprint-training program on the sand to regular preseason training, on the athletic performance and technical actions of beach handball (BH) players. Athletes were randomly assigned either to the control (CG, n = 12; BH training only) or the experimental group (EG, n = 12; plyometric + sprint + BH training). Assessments conducted before and after the training period included a squat jump, a countermovement jump, the Abalakov jump, a 15-m sprint, a modified Course-Navette endurance test, and four sport-specific BH throwing speed tests: a standing penalty throw, a 3-step running throw, a jump throw, and a 360º jump throw. The training intervention enhanced all athletic performance measures (all, p < 0.05). In contrast, the only improvement in the CG included endurance performance (p< 0.05). Significant time-group differences were noted in favor of the EG compared to the CG (p< 0.05) in the squat jump, the countermovement jump, the Abalakov jump, the jump throw velocity and 360º jump throw velocity. In conclusion, compared to BH regular training, 6 weeks of sand surface preseason plyometric and sprint training combined with regular BH training induced greater improvements in athletic performance and specific skills in BH players.

Novel Microbial Enzymes with Industrial Applications.

Eberhardt et al [...].

Structural basis of specificity in tetrameric Kluyveromyces lactis ß-galactosidase.

ß-Galactosidase or lactase is a very important enzyme in the food industry, being that from the yeast Kluyveromyces lactis the most widely used. Here we report its three-dimensional structure both in the free state and complexed with the product galactose. The monomer folds into five domains in a pattern conserved with the prokaryote enzymes of the GH2 family, although two long insertions in domains 2 and 3 are unique and related to oligomerization and specificity. The tetrameric enzyme is a dimer of dimers, with higher dissociation energy for the dimers than for its assembly. Two active centers are located at the interface within each dimer in a narrow channel. The insertion at domain 3 protrudes into this channel and makes putative links with the aglycone moiety of docked lactose. In spite of common structural features related to function, the determinants of the reaction mechanism proposed for Escherichia coli ß-galactosidase are not found in the active site of the K. lactis enzyme. This is the first X-ray crystal structure for a ß-galactosidase used in food processing.