Gut microbiome composition: link between sports performance and protein absorption?

BACKGROUND: Sufficient protein intake is essential for adequate physical condition and athletic performance. However, numerous factors can influence the absorption of consumed protein, including timing, type of protein intake, and gut microbiota. In the present study, elite male water polo players consumed a plant-based, vegan protein supplement with (n = 10) or without (n = 10) pre- and probiotics daily during the 31-day study period. METHODS: We determined the anthropometric characteristics and body composition, dietary habits, gut microbiota composition, and blood parameters of the players at the beginning and at the end of the study. Body composition parameters were analyzed using the InBody 970 bioimpedance analyzer. Gut microbiome composition was determined from stool samples by metagenome sequencing. Paired and unpaired t-tests were used to determine differences between body composition and blood parameters within the groups and between the two groups at the two different sampling times. The Wilcoxon test was used to determine the change in bacterial composition during the study. Correlations between changes in body composition, blood parameters, and taxonomic groups were analyzed using a linear correlation calculation. RESULTS: Skeletal muscle mass (p < 0.001), body cell mass (p = 0.002), arm circumference (p = 0.003), and protein mass (p < 0.001) increased, while body fat mass (p = 0.004) decreased significantly in the intervention group which consumed pre- and probiotics in addition to protein supplement. Activated acetate (reductive TCA cycle I) and propionate (pyruvate fermentation to propanoate I) pathways correlated positively with increased skeletal muscle mass (p < 0.01 and p < 0.05), and the relative abundance of butyrate-producing species showed a significant positive correlation with changes in body fat mass in the intervention group (p < 0.05). These correlations were not observed in the control group without the intake of pre- and probiotics. CONCLUSIONS: The composition of the gut microbiota may influence protein absorption and therefore body composition and consequently physical condition and sports performance.

Chronic responses of aerobic granules to the presence of graphene oxide in sequencing batch reactors.

The chronic responses of aerobic granular sludge (AGS) to the presence of graphene oxide nanoparticles (GO NPs) (5, 15, 25, 35, 45, 55, 65, 75, 85, and 95 mg/L of GO NPs for 7 days) during biological wastewater treatment processes were investigated. Bioreactor performance, extracellular polymeric substance (EPS) secretion, and microbial community characteristics were assessed. The results showed that the effects of GO NPs on bioreactor performances were dependent on the dose applied and the duration for which it was applied. At concentrations of 55, 75, and 95 mg/L, GO NPs considerably inhibited the efficiency of organic matter and ammonia removal; however, nitrite and nitrate removal rates were unchanged. Biological phosphorus removal decreased even when only low concentrations of GO NPs were used. The secretion of EPS, which could alleviate the toxicity of GO NPs, also changed. The increased amount of nanoparticles also resulted in significant changes to the bacterial community structure. Based on the amplicon sequencing of 16S rRNA genes, Paracoccus sp., Klebsiella sp., and Acidovorax species were identified as the most tolerant strains.

PCR-DGGE analysis of the bacterial composition of a kaolin slurry showing altered rheology.

Kaolin is an important industrial raw material and a basis of a range of different products. Microbial spoilage is a detrimental process observed especially in kaolin slurries, leading to low quality products and economic loss. Although the alteration of kaolin slurries in ceramic industry was observed, the process and the microbial background have not been analyzed in details. This study provides the first data using a cultivation independent molecular biological approach (PCR-DGGE) regarding the bacterial composition of an altered kaolin slurry. The results show that potential exopolymer (EPS) producer bacteria (e.g. Acinetobacter, Pseudomonas) appear in the altered kaolin slurry, which may have an important role in the modification of kaolin slurries.

Degradation of native feathers by a novel keratinase-producing, thermophilic isolate, Brevibacillus thermoruber T1E.

Strain T1E, isolated and identified as Brevibacillus thermoruber, and evolutionally distant from the known keratinolytic isolates, proved to have feather-degrading ability. During the 7-day fermentation period, T1E consumed 10 g/l native goose feathers as the sole source of carbon and energy at 50 degrees C under aerobic conditions. The isolate secreted a thermostable, keratinolytic protease, which exhibited activity optimally at pH 6.5, whilst it was inhibited at alkaline pH. The keratin cleavage and catabolism resulted in the accumulation of free aspartic acid and soluble peptides with maximum values of 31.6 and 720 mg/l, respectively. The majority of the fermentation end-products were found to be small oligopeptides with an average molecular mass of 2275 Da.

Isolation and characterization of a novel n-alkane-degrading strain, Acinetobacter haemolyticus AR-46.

Strain AR-46, isolated and identified as Acinetobacter haemolyticus, evolutionally distant from the known hydrocarbon-degrading Acinetobacter spp., proved to have excellent long-chain n-alkane-degrading ability. This is the first detailed report on an n-alkane-utilizing strain belonging to this species. The preferred substrate is n-hexadecane, with an optimal temperature of 37 degrees C under aerobic conditions. Five complete and two partial open reading frames were sequenced and correlated with the early steps of monoterminal oxidation-initiated n-alkane mineralization. The encoded protein sequences and the arrangement of these genes displayed high similarity to those found in Acinetobacter sp. M-1, but AR-46 seemed to have only one alkane hydroxylase gene, with a completely different induction profile. Unique behaviour was also observed in n-alkane bioavailability. Substrate uptake occurred through the hydrophobic surface of n-alkane droplet-adhered cells possessing long, thick fimbriae, which were presumed to play a major role in n-alkane solubilization. A majority of the cells was in detached form, with thick, but short fimbriae. These free cells were permanently hydrophilic, unlike the cells of other Acinetobacter strains.

Nitrate-dependent salicylate degradation by Pseudomonas butanovora under anaerobic conditions.

Nitrate-dependent salicylate degradation by the denitrifying Pseudomonas butanovora was investigated and the molar ratio of the cometabolism under anaerobic circumstances was determined. The bacterium was able to utilize salicylate as an electron donor for the reduction of nitrate. Salicylate was eliminated via catechol, which is degraded by means of catechol 2,3-oxygenases (meta-cleavage), forming 2-hydroxymuconic semialdehyde. The molar ratios of NO(3)(-)-N:salicylate existing during the experiment accorded well with the assumed 1:1 molar ratio. The tolerances of the growth, the salicylate degradation and the denitrification of P. butanovora to various heavy metal ions were also studied. Although the strain was tolerant to Pb(2+) and Cu(2+) up to 1 mM in complete medium, salicylate utilization took place only up to a concentration of 0.1 mM for both heavy metal ions. Of the heavy metal ions investigated, Cd(2+) (at a concentration of 0.05 mM) displayed the highest inhibitory effect on salicylate degradation by P. butanovora.

Biological denitrification in a continuous-flow pilot bioreactor containing immobilized Pseudomonas butanovora cells.

Pseudomonas butanovora, a novel denitrifying bacterium, was immobilized in composite beads and filled into a reactor system. The pilot bioreactor average denitrification activity was at ethanol-C:nitrate-N ratios of 3:1 and 1.5:1 0.88 and 0.54 kg NO3(-)-Nm(-3) d(-1), respectively. The denitrification was stable in spite of the relatively low hydraulic retention times of 2.47 and 3 h. The nitrate content of the influent was almost completely reduced at the first level of the bioreactor and the nitrite formed underwent reduction in the upper part of the reactor. The experimentally determined optimum ethanol-C:nitrate-N ratio was 1.41 +/- 0.41. In consequence of the aerobic conditions, the acetic acid produced by the oxygenation of ethanol was also detectable in the reactor effluent. The pH of the effluent (7.58) never exceeded the acceptable maximum (8.5). The nitrate removal efficiency of the cells was nearly 1000% at both C:N ratios, and the nitrite content of the effluent was around the prescribed limit throughout the continuous operation. This continuous-flow pilot bioreactor containing immobilized P. butanovora cells proved an efficient denitrification system with a relatively low retention time.

The effects of NaCl and some heavy metals on the denitrification activity of Ochrobactrum anthropi.

Ochrobactrum anthropi is a well-known Gram-negative bacterium, with the ability to degrade atrazine, urea-formaldehyde and chlorophenols. Investigation were made of the nitrate and nitrite reduction capacities of the strain in succinate and glucose media, and the tolerance of its denitrification to NaCl and some heavy metals. Succinate proved to be a better carbon source to drive denitrification by O. anthropi. Batch fermentation studies in anaerobic succinate medium indicated reduction capacities of 85.4 +/- 9.1 and 48.6 +/- 5.2 mgh(-1)g(-1) dry cell for NO(3) (-) and NO(2) (-), respectively. The nitrite accumulation of the cells revealed that O. anthropi is a group C denitrifying bacterium. Its growth in DSM 1 broth containing NaCl up to 40 g l(-1) demonstrates that O. anthropi belongs in the group of moderately halophilic bacteria. Despite the fact that 42.5 g NaCl l(-1) caused 50% growth inhibition in DSM 1 broth, the cells in the stationary phase readily tolerated NaCl concentrations up to 100 g l(-1). Complete denitrification was achieved in test media containing 30 g NaCl l(-1) after 1 week and the nitrate reductase retained its activity up to 100 g NaCl l(-1). The cells were tolerant to Hg, Zn, Pb, Cu and Ni, and N(2) was producted at tolerated concentrations of the metal in the cases of Hg and Pb.