Non-human peptides revealed in blood reflect the composition of intestinal microbiota.

BACKGROUND: The previously underestimated effects of commensal gut microbiota on the human body are increasingly being investigated using omics. The discovery of active molecules of interaction between the microbiota and the host may be an important step towards elucidating the mechanisms of symbiosis. RESULTS: Here, we show that in the bloodstream of healthy people, there are over 900 peptides that are fragments of proteins from microorganisms which naturally inhabit human biotopes, including the intestinal microbiota. Absolute quantitation by multiple reaction monitoring has confirmed the presence of bacterial peptides in the blood plasma and serum in the range of approximately 0.1 nM to 1 µM. The abundance of microbiota peptides reaches its maximum about 5 h after a meal. Most of the peptides correlate with the bacterial composition of the small intestine and are likely obtained by hydrolysis of membrane proteins with trypsin, chymotrypsin and pepsin - the main proteases of the gastrointestinal tract. The peptides have physicochemical properties that likely allow them to selectively pass the intestinal mucosal barrier and resist fibrinolysis. CONCLUSIONS: The proposed approach to the identification of microbiota peptides in the blood, after additional validation, may be useful for determining the microbiota composition of hard-to-reach intestinal areas and monitoring the permeability of the intestinal mucosal barrier.

Evaluation of multiple reaction monitoring cubed performed by a quadrupole-linear ion trap mass spectrometer for quantitative determination of 6-sulfatoxymelatonin in urine.

Liquid chromatography (LC) - mass spectrometry quantitative analysis of substances in biological samples is usually performed in the multiple reaction monitoring (MRM) variant. In complex biological matrices, strong interferences can be observed when using the LC-MRM method. Interference levels can be significantly reduced by using LC - multiple reaction monitoring cubed (MRM3). 6-sulfatoxymelatonin (6-SM) is a metabolite of melatonin, an important regulator of many biological processes. The quantitative analysis of 6-SM in urine allows monitoring of the melatonin level in the blood. The aim of the present work was to evaluate the LC-MRM3 method for the quantitative determination of 6-SM in urine. We found that for 6-SM in aqueous solutions, under some parameters of the MRM3 experiment, the effect of degradation of the MRM3 signal is observed. When analyzing 6-SM in urine, this signal degradation effect was significantly reduced. We have shown that optimization of such parameters of the MRM3 method as the linear ion trap fill time, the number of scans to sum, and the range of triple-stage scan allows obtaining the LC-MRM3 method, which is comparable to the LC-MRM in sensitivity and significantly exceeds it in selectivity.

Skin Microbiota in Contact Sports Athletes and Selection of Antiseptics for Professional Hygiene.

BACKGROUND: The aim of this study was to assess changes in skin microbiota of wrestlers during training sessions and to determine the sensitivity of hemolytic bacterial isolates to antiseptics. METHODS: The main skin bacterial isolates obtained from the skin of 15 wrestlers were identified by cultivation method, with the following MALDI Biotyper and 16S rRNA gene sequencing methods. The sensitivity of hemolytic isolates to antiseptics (Veltosept-2, Cutasept F, Chlorhexidine, Miramistin, and Hydrogen Peroxide) was evaluated by measuring the size of bacterial growth inhibition zone on agar plates. RESULTS: Opportunistic bacteria of the species Bacillus cereus, Staphylococcus aureus, S. epidermidis, and S. saprophyticus were the most commonly found species in skin microbiota of wrestlers before and after training sessions. Representatives of all these species mostly had a hemolytic activity. An alcohol-containing antiseptic Veltosept-2 showed the strongest inhibitory effect on the bacterial isolates of athletes' skin microbiota most frequently detected in this study. CONCLUSIONS: The general increase in the bacterial colonization of wrestlers' skin, as well as the presence of hemolytic forms of opportunistic bacteria in cutaneous microbiota, indicates dysbiotic changes and a decrease in the protective features of the host organism. Veltosept-2 application can reduce the incidence of skin infections in contact sports athletes with the highest efficiency.