Short-chain fatty acids accompanying changes in the gut microbiome contribute to the development of hypertension in patients with preeclampsia.

Preeclampsia (PE) is regarded as a pregnancy-associated hypertension disorder that is related to excessive inflammatory responses. Although the gut microbiota (GM) and short-chain fatty acids (SCFAs) have been related to hypertension, their effects on PE remain unknown. We determined the GM abundance and faecal SCFA levels by 16S ribosomal RNA (rRNA) sequencing and gas chromatography, respectively, using faecal samples from 27 patients with severe PE and 36 healthy, pregnant control subjects. We found that patients with PE had significantly decreased GM diversity and altered GM abundance. At the phylum level, patients with PE exhibited decreased abundance of Firmicutes albeit increased abundance of Proteobacteria; at the genus level, patients with PE had lower abundance of Blautia, Eubacterium_rectale, Eubacterium_hallii, Streptococcus, Bifidobacterium, Collinsella, Alistipes, and Subdoligranulum, albeit higher abundance of Enterobacter and Escherichia_Shigella. The faecal levels of butyric and valeric acids were significantly decreased in patients with PE and significantly correlated with the above-mentioned differential GM abundance. We predicted significantly increased abundance of the lipopolysaccharide (LPS)-synthesis pathway and significantly decreased abundance of the G protein-coupled receptor (GPCR) pathway in patients with PE, based on phylogenetic reconstruction of unobserved states (PICRUSt). Finally, we evaluated the effects of oral butyrate on LPS-induced hypertension in pregnant rats. We found that butyrate significantly reduced the blood pressure (BP) in these rats. In summary, we provide the first evidence linking GM dysbiosis and reduced faecal SCFA to PE and demonstrate that butyrate can directly regulate BP in vivo, suggesting its potential as a therapeutic agent for PE.

Phenyl-γ-valerolactones and phenylvaleric acids, the main colonic metabolites of flavan-3-ols: synthesis, analysis, bioavailability, and bioactivity.

Covering: 1958 to June 2018 Phenyl-γ-valerolactones (PVLs) and their related phenylvaleric acids (PVAs) are the main metabolites of flavan-3-ols, the major class of flavonoids in the human diet. Despite their presumed importance, these gut microbiota-derived compounds have, to date, in terms of biological activity, been considered subordinate to their parent dietary compounds, the flavan-3-ol monomers and proanthocyanidins. In this review, the role and prospects of PVLs and PVAs as key metabolites in the understanding of the health features of flavan-3-ols have been critically assessed. Among the topics covered, are proposals for a standardised nomenclature for PVLs and PVAs. The formation, bioavailability and pharmacokinetics of PVLs and PVAs from different types of flavan-3-ols are discussed, taking into account in vitro and animal studies, as well as inter-individual differences and the existence of putative flavan-3-ol metabotypes. Synthetic strategies used for the preparation of PVLs are considered and the methodologies for their identification and quantification assessed. Metabolomic approaches unravelling the role of PVLs and PVAs as biomarkers of intake are also described. Finally, the biological activity of these microbial catabolites in different experimental models is summarised. Knowledge gaps and future research are considered in this key area of dietary (poly)phenol research.

A Method for Controlled Odor Delivery in Olfactory Field-Testing.

A widely recognized limitation in mammalian olfactory research is the lack of current methods for measuring odor availability (i.e., the quantifiable amount of odor presented and thus available for olfaction) of training or testing materials during behavioral or operational testing. This research utilized an existing technology known as Controlled Odor Mimic Permeation Systems (COMPS) to produce a reproducible, field-appropriate odor delivery method that can be analytically validated and quantified, akin to laboratory-based research methods, such as permeation devices that deliver a stable concentration of a specific chemical vapor for instrumental testing purposes. COMPS were created for 12 compounds across a range of carbon chain lengths and functional groups in such a way to produce similar permeation rates for all compounds. Using detection canines as a model, field-testing was performed to assess the efficacy of the method. Additionally headspace concentrations over time were measured as confirmation of odor availability using either externally sampled internal standard-solid phase microextraction-gas chromatography-mass spectrometry (ESIS-SPME-GC-MS) or collection onto a programmable temperature vaporizing (PTV) GC inlet with MS detection. Finally, lifetime usage was considered. An efficient method for producing and measuring reliable odor availabilities across various chemical functional groups was developed, addressing a noted gap in existing literature that will advance canine and other nonhuman mammal research testing.

Short communication: Blood metabolites, body reserves, and feed efficiency of high-producing dairy cows that varied in ruminal pH when fed a high-concentrate diet.

Recent studies report considerable variation in ruminal pH for lactating dairy cows even when fed the same diet. We hypothesized that blood metabolites would be indicators of low ruminal pH, and hence could be used as predictors to help manage this variability. The objective of the study was to determine whether blood metabolite concentrations, body reserves, and feed efficiency were associated with ruminal pH in high-producing dairy cows fed a high-concentrate diet. Seventy-eight individually fed lactating dairy cows (days in milk = 103 ± 27; body weight = 638 ± 77 kg at the start; mean ± SD) were fed a diet consisting of 35% forage and 65% concentrate (dry matter basis). Cows were adapted for 14 d and then were sampled for 10 d. Ruminal pH was measured by rumenocentesis for all cows at the end of the study 4 h after feeding, and reticular pH was measured on a subsample of 14 cows via indwelling sensors for 5 consecutive days. Cows were classified according to rumenocentesis pH as high (pH ≥ 6.0; n = 26), medium (5.8 ≤ pH < 6; n = 21), and low (pH < 5.8; n = 31). Cows were also classified according to reticular pH as high if pH <5.8 persisted <330 min/d (an average of 78 min/d; n = 5) or low if duration of pH <5.8 was ≥330 min/d (an average of 920 min/d; n = 9). The classification based on rumenocentesis pH revealed that serum activity of aspartate aminotransferase (AST) was greater in cows with low ruminal pH (70.7 U/L) than cows with high (56.6 U/L) and medium (59.9 U/L) ruminal pH. Also, the blood urea nitrogen concentration was greater in cows with low ruminal pH (13.6 mg/dL) than cows with medium (12.2 mg/dL) and high (12.5 mg/dL) ruminal pH. Blood albumin concentration was greater for cows with low ruminal pH than for cows with medium and high ruminal pH. The classification based on reticular pH also resulted in a trend of greater AST activity and greater blood urea nitrogen concentration in the blood of cows with low pH. Regression analysis showed high serum concentration of AST was associated with high valerate concentration in ruminal fluid (R2 = 0.14), low rumenocentesis pH (R2 = 0.10), and low milk fat percentage (R2 = 0.06). Glucose, triglyceride, cholesterol, globulin, alkaline phosphates, and serum amyloid A did not differ among the different ruminal pH classes. Low pH cows (reticular and ruminal) had less backfat thickness measured via ultrasound, and cows with low ruminal pH tended to have greater milk:feed ratio. Results indicated that cows that differ in ruminal pH also had different concentrations of blood metabolites and backfat thickness, and AST activity in blood may be a plausible indicator of ruminal pH in dairy cows. Further studies on the applicability of AST in blood as a biomarker for detecting low ruminal pH in dairy cows are warranted.

Isovaleric acid in stool correlates with human depression.

OBJECTIVE: Human depression is a major burden, both on the individuals who suffer from the disease and on society at large. Traditionally, depression has been linked to psychological and biological causes, but there has been increasing interest in the gut-brain axis. In this regard, we have recently shown that specific bacteria are correlated with human depression, and we hypothesize that volatile fatty acids (VFAs) are mediators. METHODS: Here, we analyzed the direct correlation between VFAs, depression and cortisol in a cohort consisting of 34 depressed patients and 17 controls. RESULTS: We found statistically significant correlations between depression and the VFA isovaleric acid, as well as between isovaleric acid and cortisol. Furthermore, bacteria that previously have been identified as being correlated with depression were also correlated with isovaleric acid. Isovaleric acid showed a bimodal distribution in which the depressed patients were overrepresented in the high level group (P < 0.00005, binominal test). DISCUSSION: It has recently been shown that gut-derived VFAs can cross the blood-brain barrier, where isovaleric acid interferes with synaptic neurotransmitter release. The multiple correlation patterns, in addition to a potential mechanistic model, point towards a potential causal relationship between depression and isovaleric acid.

Effect of non-surgical periodontal treatment on short chain fatty acid levels in gingival crevicular fluid of patients with generalized aggressive periodontitis.

BACKGROUND AND OBJECTIVE: Short chain fatty acids (SCFAs) play important roles in periodontal diseases. However, the concentrations of SCFAs in gingival crevicular fluid of patients with aggressive periodontitis are not known. The aim of this intervention study was to investigate the influences of non-surgical periodontal therapy on levels of SCFAs in the gingival crevicular fluid of patients with generalized aggressive periodontitis (G-AgP), and analyze the concentrations of SCFAs in sites with or without the detected putative periodontal pathogens. MATERIAL AND METHODS: Eighty gingival crevicular fluid samples (four per subject) were collected on filter paper strips from patients with G-AgP (n = 20; mean age 24.5 years), before and at 2 wk, 2, 4 and 6 mo after non-surgical periodontal treatment. Eighty gingival crevicular fluid samples (four per subject) were collected from periodontally healthy controls (n = 20; mean age 26.2 years). Concentrations of formic acid, succinic acid, acetic acid, lactic acid, propionic acid, butyric acid and isovaleric acid from the supernatant of gingival crevicular fluid samples were measured by high performance capillary electrophoresis. Porphyromonas gingivalis, Treponema denticola, Aggregatibacter actinomycetemcomitans, Prevotella intermedia and Fusobacterium nucleatum from the precipitate of the same pretreatment samples of gingival crevicular fluids were analyzed by polymerase chain reaction amplification. RESULTS: The clinical parameters of patients with G-AgP during the 6 mo after non-surgical periodontal treatment were improved remarkably. The formic acid concentration increased significantly after treatment; the level of formic acid was lower in the P. gingivalis-, T. denticola-, P. intermedia- or F. nucleatum-positive sites compared with the negative sites. The concentrations of acetic acid, propionic acid and butyric acid reduced significantly after treatment and reached the lowest level at 2 wk post-treatment, although showed a tendency to increase after 2 mo post-treatment, and the three SCFA levels were significantly higher in P. gingivalis-, T. denticola-, P. intermedia- or F. nucleatum-positive sites compared with those in the negative sites. CONCLUSION: Non-surgical periodontal treatment resulted in a significant decrease of acetic acid, propionic acid, butyric acid levels and increase of formic acid level in gingival crevicular fluids in patients with G-AgP, accompanied by improvement in clinical parameters. A marked lower level of formic acid, as well as higher levels of acetic acid, propionic acid and butyric acid in gingival crevicular fluid of patients with G-AgP was consistent with periodontal pathogen infection.

Enantioselective synthesis of (S)-2-cyano-2-methylpentanoic acid by nitrilase.

The nitrilase gene of Rhodococcus rhodochrous J1 was expressed in Escherichia coli using the expression vector, pKK223-3. The recombinant E. coli JM109 cells hydrolyzed enantioselectively 2-methyl-2-propylmalononitrile to form (S)-2-cyano-2-methylpentanoic acid (CMPA) with 96 % e.e. Under optimized conditions, 80 g (S)-CMPA l(-1) was produced with a molar yield of 97 % at 30 °C after a 24 h without any by-products.

Effect of exclusive enteral nutrition on gut microflora function in children with Crohn's disease.

OBJECTIVE: Exclusive enteral nutrition (EEN) is a first-line treatment in children with active Crohn's disease (CD) but is seldom used in adults with active disease. The mode of action of EEN in suppressing mucosal inflammation is not fully understood, but modulation of intestinal microflora activity is one possible explanation. The aim of this study was to investigate the effect of 6-week EEN in children with active CD, with special reference to intestinal microflora function. MATERIALS AND METHODS: Fecal samples from 18 children (11 boys, 7 girls; median age 13.5 years) with active CD (13 children with small bowel/colonic and 5 with perianal disease) were analyzed for short chain fatty acid (SCFA) pattern as marker of gut microflora function. The children were studied before and after EEN treatment. Results from 12 healthy teenagers were used for comparison. RESULTS: Eleven (79%) of the children with small bowel/colonic CD responded clinically positively to EEN treatment showing decreased levels of pro-inflammatory acetic acid as well as increased concentrations of anti-inflammatory butyric acids and also of valeric acids, similar to the levels in healthy age-matched children. In children with active perianal CD, however, EEN had no positive effect on clinical status or inflammatory parameters. CONCLUSIONS: The authors present new data supporting the hypothesis that the well-documented anti-inflammatory effect of EEN in children with active small bowel/colonic CD is brought about by modulation of gut microflora activity, resulting in an anti-inflammatory SCFA pattern. By contrast, none of the children with perianal disease showed clinical or biochemical improvement after EEN treatment.

Longitudinal study of volatile fatty acids in the gingival crevicular fluid of patients with periodontitis before and after nonsurgical therapy.

BACKGROUND AND OBJECTIVE: Short-chain fatty acids (SCFAs) are important metabolic products of subgingival organisms and their concentrations are associated with the status of inflammation. The purpose of this study was to observe and analyze the change in concentration of SCFAs in the gingival crevicular fluid of patients with chronic periodontitis before and after periodontal treatment. MATERIAL AND METHODS: Gingival crevicular fluid samples were taken from 21 patients with chronic periodontitis before periodontal treatment and 2 wk, and 2, 4 and 6 mo after treatment. The concentrations of six different SCFAs in the gingival crevicular fluid were measured using high-performance capillary electrophoresis. The presence of porphyromonas gingivalis in the same pretreatment gingival crevicular fluid samples used to measure SCFAs was analyzed using PCR amplification. RESULTS: Two weeks after periodontal treatment, the concentrations of lactic acid, propionic acid, butyric acid and isovaleric acid in the gingival crevicular fluid of patients with chronic periodontitis had decreased to the levels found in the healthy control group. However, the concentration of formic acid had increased. Statistically significant differences were found in the levels of these SCFAs before and after treatment. In the longitudinal observation, the concentrations of butyric acid and isovaleric acid in the gingival crevicular fluid had increased to a high level 2 mo after treatment. At the last two study time-points (4 and 6 mo after treatment), butyric acid and isovaleric acid were still present at a high level and showed a tendency to continue to increase. In contrast, the concentration of formic acid in gingival crevicular fluid showed a gradual decrease over the study period. CONCLUSIONS: The concentration of formic acid in the gingival crevicular fluid has an inverse relationship with the severity of periodontitis, whereas the increased concentrations of butyric and isovelaric acids during the long-term observation period after therapy may indicate the status of recolonization of periodontal pathogens and reflect the subgingival ecology. These two fatty acids could be used as indicators for the development and progression of periodontitis.

Clinical utility of a novel colorimetric chair side test for oral malodour.

AIM: The aim of this study was to evaluate the utility of a simple colorimetric chair side test detecting amines in saliva as an adjunct test in the oral malodour diagnosis. MATERIAL AND METHODS: Non-stimulated saliva samples were collected from 100 volunteers with different degrees of oral malodour. The amount of amines detected by the test was estimated clinically (colorimetric test), confirmed semi quantitatively in the laboratory (standard addition method) and consequently compared with (i) the organoleptic score (OLS); (ii) the volatile sulphur compounds (VSCs) levels (OralChroma(™)) and (iii) the amount of amines detected by means of gas chromatography - mass spectroscopy. RESULTS: The chair side test correlated well (Spearman correlation coefficient: 0.46-0.77), with the OLS, the level of VSCs, and the amines determined by using gas chromatography - mass spectroscopy. The results of the new test for patients with and without oral malodour were significantly different (Mann-Whitney U-test, p < 0.0001). The sensitivity, specificity, and positive and negative predictive value of this chair side test were similar to those of the VSCs evaluations. CONCLUSIONS: These results support the "fit for purpose" of the new chair side test as adjunctive diagnostic tool for oral malodour.

Acid stress-mediated metabolic shift in Lactobacillus sanfranciscensis LSCE1.

Lactobacillus sanfranciscensis LSCE1 was selected as a target organism originating from recurrently refreshed sourdough to study the metabolic rerouting associated with the acid stress exposure during sourdough fermentation. In particular, the acid stress induced a metabolic shift toward overproduction of 3-methylbutanoic and 2-methylbutanoic acids accompanied by reduced sugar consumption and primary carbohydrate metabolite production. The fate of labeled leucine, the role of different nutrients and precursors, and the expression of the genes involved in branched-chain amino acid (BCAA) catabolism were evaluated at pH 3.6 and 5.8. The novel application of the program XCMS to the solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) data allowed accurate separation and quantification of 2-methylbutanoic and 3-methylbutanoic acids, generally reported as a cumulative datum. The metabolites coming from BCAA catabolism increased up to seven times under acid stress. The gene expression analysis confirmed that some genes associated with BCAA catabolism were overexpressed under acid conditions. The experiment with labeled leucine showed that 2-methylbutanoic acid originated also from leucine. While the overproduction of 3-methylbutanoic acid under acid stress can be attributed to the need to maintain redox balance, the rationale for the production of 2-methylbutanoic acid from leucine can be found in a newly proposed biosynthesis pathway leading to 2-methylbutanoic acid and 3 mol of ATP per mol of leucine. Leucine catabolism to 3-methylbutanoic and 2-methylbutanoic acids suggests that the switch from sugar to amino acid catabolism supports growth in L. sanfranciscensis in restricted environments such as sourdough characterized by acid stress and recurrent carbon starvation.

Inhibition of microbial production of the malodorous substance isovaleric acid by 4,4' dichloro 2-hydroxydiphenyl ether (DCPP).

Human body malodour is a complex phenomenon. Several types of sweat glands produce odorless secretions that are metabolized by a consortium of skin-resident microorganisms to a diverse set of malodorous substances. Isovaleric acid, a sweaty-smelling compound, is one major malodorous component produced by staphylococci with the skin-derived amino acid L-leucine as a substrate. During wearing, fabrics are contaminated with sweat and microorganisms and high humidity propagates growth and microbial malodour production. Incomplete removal of sweat residues and microorganisms from fabrics during laundry with bleach-free detergents and at low temperatures elevate the problem of textile malodour. This study aimed to analyze the inhibitory effect of the antimicrobial 4,4' dichloro 2-hydroxydiphenyl ether (DCPP) on the formation of isovaleric acid on fabrics. Therefore, GC-FID- and GC-MS-based methods for the analysis of isovaleric acid in an artificial human sweat-mimicking medium and in textile extracts were established. Here, we show that antimicrobials capable to deposit on fabrics during laundry, such as DCPP, are effective in growth inhibition of typical malodour-generating bacteria and prevent the staphylococcal formation of isovaleric acid on fabrics in a simple experimental setup. This can contribute to increased hygiene for mild laundry care approaches, where bacterial contamination and malodour production represent a considerable consumer problem.

The egg and larval pheromone dodecanoic acid mediates density-dependent oviposition of Phlebotomus papatasi.

BACKGROUND: Gravid females assess the conditions of oviposition sites to secure the growth and survival of their offspring. Conspecific-occupied sites may signal suitable oviposition sites but may also impose risk due to competition or cannibalism at high population density or heterogeneous larval stage structure, respectively. Chemicals in the habitat, including chemicals emitted from other organisms, serve as cues for females to assess habitat conditions. Here, we investigated the attraction and oviposition preference of the Old World cutaneous leishmaniasis vector, Phlebotomus papatasi, to young and old conspecific stages, including eggs and evaluated the effect of a semiochemical associated with eggs and neonate larvae. METHODS: Attraction and oviposition preference of Ph. papatasi to each of various life stages (eggs, first-, second-, third-, fourth-instar larvae, pupae and male and female adults) was investigated using cage and oviposition jar behavioral assays. Identification of organic chemical compounds extracted from eggs was performed using GC-MS and chemicals were tested in the same behavioral assays in a dose-response manner. Behavioral responses were statistically analyzed using logistic models. RESULTS: Gravid Ph. papatasi females were significantly attracted to and preferred to oviposit on medium containing young life stages (eggs and first instars). This preference decreased towards older life stages. Dose effect of eggs indicated a hump-shaped response with respect to attraction but a concave-up pattern with respect to oviposition. Chemical analysis of semiochemicals from eggs and first-instar larvae revealed the presence of dodecanoic acid (DA) and isovaleric acid. Sand flies were attracted to and laid more eggs at the lowest DA dose tested followed by a negative dose-response. CONCLUSIONS: Findings corroborated our hypothesis that gravid sand flies should prefer early colonized oviposition sites as indicators of site suitability but avoid sites containing older stages as indicators of potential competition. Findings also supported the predictions of our hump-shaped oviposition regulation (HSR) model, with attraction to conspecific eggs at low-medium densities and switching to repellence at high egg densities. This oviposition behavior is mediated by DA that was identified from surface extracts of both eggs and first-instar larvae. Isovaleric acid was also found in extracts of both stages.

Biosynthesis and characterization of 3-hydroxyalkanoate terpolyesters with adjustable properties by Aeromonas hydrophila.

Polyhydroxyalkanoates (PHA) terployesters P(3HB-co-3HV-co-3HHx) consisting of 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), and 3-hydroxyhexanoate (3HHx) were produced by wild-type Aeromonas hydrophila 4AK4, its recombinant harboring PHA synthesis genes phaPCJ encoding PHA binding protein phasin, PHA synthase, and enoyl-CoA hydratase, and another its recombinant harboring phaAB encoding beta-ketothiolase and acetoacetyl-CoA reductase, respectively, when grown in lauric acid and/or valerate. The terpolyesters produced by A. hydrophila 4AK4 (phaAB) grown in velarate were found to produce copolymers P(3HB-co-3HV) containing high 3HV fractions with a maximum of 99 mol% 3HV. In terpolyesters, 3HV ranged from 9 to 32 mol% depending on the valerate concentration and strain used. A maximal terpolyester P(3HB-co-3HV-co-3HHx) content in dry cells was 71 wt%. Transmission electron microscopy study of A. hydrophila 4AK4 harboring phaPCJ revealed the full occupation of terpolyester P(3HB-co-3HV-co-HHx) in the cellular spaces. Terpolyesters with various monomer compositions showed changing thermal and mechanical properties. Those with higher 3HV fractions demonstrated an improved property over the lower HV containing ones.

High-titer production of monomeric hydroxyvalerates from levulinic acid in Pseudomonas putida.

Hydroxyacids represent an important class of compounds that see application in the production of polyesters, biodegradable plastics and antibiotics, and that serve as useful chiral synthetic building blocks for other fine chemicals and pharmaceuticals. An economical, high-titer method for the production of 4-hydroxyvalerate (4HV) and 3-hydroxyvalerate (3HV) from the inexpensive and renewable carbon source levulinic acid was developed. These hydroxyvalerates were produced by periodically feeding levulinate to Pseudomonas putida KT2440 expressing a recombinant thioesterase II (tesB) gene from Escherichia coli K12. The titer of 4HV in shake flask culture reached 13.9+/-1.2 g L(-1) from P. putida tesB(+) cultured at 32 degrees C in LB medium periodically supplemented with glucose and levulinate. The highest 3HV titer obtained was 5.3+/-0.1 g L(-1) in M9 minimal medium supplemented with glucose and levulinate.

HS-SPME-GC-MS analysis of body odor to test the efficacy of foot deodorant formulations.

BACKGROUND/PURPOSE: Foot malodor is mostly due to short-chain fatty acids produced by bacterial metabolism of eccrine sweating. We aimed to develop a protocol for an objective (instrumental) efficacy evaluation of foot deodorant formulations. METHODS: Head-space solid-phase microextractions of target fatty acids from the feet of six healthy volunteers were analyzed by GC-MS. A comparative analysis of the treated vs. the untreated foot was performed in each subject after washing the feet with a physiologic solution and incubating at 36 degrees C for 24-72 h in tryptic soy agar growth medium. RESULTS: Acetic, butyric, isobutyric and isovaleric acids were identified as the main contributors to foot malodor in the majority of volunteers. Propionic, valeric and isocaproic acids were also detected in some subjects. Comparative analysis according to the protocol developed showed a statistically significant (P<0.01) reduction of target fatty acids ranging from -26.6% to -77.0%. CONCLUSION: The protocol developed is a convenient, sensitive and non-invasive method to test the efficacy of foot deodorant formulations in human volunteers.

Matrix binding of T-2 toxin: structure elucidation of reaction products and indications on the fate of a relevant food-borne toxin during heating.

This study deals with the influence of food matrix components on the degradation of the mycotoxins T-2 toxin (T-2) and HT-2 toxin (HT-2) and with the binding of T-2 to starch during thermal food processing. Both mycotoxins were heated in a simulated food environment and subsequently analyzed via HPLC-HRMS to generate degradation curves and to draw conclusions regarding the thermal degradation under food processing conditions. Thermal degradation increased generally with increasing time and temperature with a maximum degradation rate of 93% (T-2) and 99% (HT-2). Furthermore, HRMS data were exploited to screen the samples for degradation products. In model heating experiments, T-2 was bound to 1-O-methyl-α-D-glucopyranoside, a model compound that was used to simulate starch. The formed reaction products were isolated and identified by NMR, giving detailed insights into a potential binding of T-2 to starch. In the next step, further model heating experiments were performed, which proved the covalent binding of T-2 to starch. Finally, the amount of matrix-bound T-2 was estimated roughly in a semi-quantitative approach in the model heating experiments as well as during cookie-making via GC-MS analysis of the isovaleric acid ester moiety of T-2, released after alkaline hydrolysis.

Fate of 6:2 fluorotelomer sulfonic acid in pumpkin (Cucurbita maxima L.) based on hydroponic culture: Uptake, translocation and biotransformation.

6:2 fluorotelomer sulfonic acid (6:2 FTSA) is currently used as an alternative to perfluorooctanesulfonate (PFOS) and is widely detected in the environment. The uptake, translocation and biotransformation of 6:2 FTSA in pumpkin (Cucurbita maxima L.) were investigated by hydroponic exposure for the first time. The root concentration factor (RCF) of 6:2 FTSA was 2.6-24.2 times as high as those of perfluoroalkyl acids (PFAAs) of the same or much shorter carbon chain length, demonstrating much higher bioaccumulative ability of 6:2 FTSA in pumpkin roots. The translocation capability of 6:2 FTSA from root to shoot depended on its hydrophobicity. Six terminal perfluorocarboxylic acid (PFCA) metabolites, including perfluoroheptanoic acid (PFHpA), perfluorohexanoic acid (PFHxA), perfluoropentanoic acid (PFPeA), perfluorobutanoic acid (PFBA), perfluoropropionic acid (PFPrA) and trifluoroacetic acid (TFA) were found in pumpkin roots and shoots. PFHpA was the primary metabolite in roots, while PFBA was the major product in shoots. 1-aminobenzotriazole (ABT), a cytochromes P450 (CYPs) suicide inhibitor, could decrease the concentrations of PFCA products with dose-dependent relationships in pumpkin tissues, implying the role of CYP enzymes involved in plant biotransformation of 6:2 FTSA. This study indicated that the application of 6:2 FTSA can lead to the occurrence of PFCAs (C2-C7) in plants.

Characterization of organosulfates from the photooxidation of isoprene and unsaturated fatty acids in ambient aerosol using liquid chromatography/(-) electrospray ionization mass spectrometry.

In the present study, we have characterized in detail the MS(2) and MS(3) fragmentation behaviors, using electrospray ionization (ESI) in the negative ion mode, of previously identified sulfated isoprene secondary organic aerosol compounds, including 2-methyltetrols, 2-methylglyceric acid, 2-methyltetrol mononitrate derivatives, glyoxal and methylglyoxal. A major fragmentation pathway for the deprotonated molecules of the sulfate esters of 2-methyltetrols and 2-methylglyceric acid and of the sulfate derivatives of glyoxal and methylglyoxal is the formation of the bisulfate [HSO(4)](-) anion, while the deprotonated sulfate esters of 2-methyltetrol mononitrate derivatives preferentially fragment through loss of nitric acid. Rational interpretation of MS(2), MS(3) and accurate mass data led to the structural characterization of unknown polar compounds in K-puszta fine aerosol as organosulfate derivatives of photooxidation products of unsaturated fatty acids, i.e. 2-hydroxy-1,4-butanedialdehyde, 4,5- and 2,3-dihydroxypentanoic acids, and 2-hydroxyglutaric acid, and of alpha-pinene, i.e. 3-hydroxyglutaric acid. The deprotonated molecules of the sulfated hydroxyacids, 2-methylglyceric acid, 4,5- and 2,3-dihydroxypentanoic acid, and 2- and 3-hydroxyglutaric acids, showed in addition to the [HSO(4)](-) ion (m/z 97) neutral losses of water, CO(2) and/or SO(3), features that are characteristic of humic-like substances. The polar organosulfates characterized in the present work are of climatic relevance because they may contribute to the hydrophilic properties of fine ambient aerosol. In addition, these compounds probably serve as ambient tracer compounds for the occurrence of secondary organic aerosol formation under acidic conditions.

Understanding the microbial basis of body odor in pre-pubescent children and teenagers.

BACKGROUND: Even though human sweat is odorless, bacterial growth and decomposition of specific odor precursors in it is believed to give rise to body odor in humans. While mechanisms of odor generation have been widely studied in adults, little is known for teenagers and pre-pubescent children who have distinct sweat composition from immature apocrine and sebaceous glands, but are arguably more susceptible to the social and psychological impact of malodor. RESULTS: We integrated information from whole microbiome analysis of multiple skin sites (underarm, neck, and head) and multiple time points (1 h and 8 h after bath), analyzing 180 samples in total to perform the largest metagenome-wide association study to date on malodor. Significant positive correlations were observed between odor intensity and the relative abundance of Staphylococcus hominis, Staphylococcus epidermidis, and Cutibacterium avidum, as well as negative correlation with Acinetobacter schindleri and Cutibacterium species. Metabolic pathway analysis highlighted the association of isovaleric and acetic acid production (sour odor) from enriched S. epidermidis (teen underarm) and S. hominis (child neck) enzymes and sulfur production from Staphylococcus species (teen underarm) with odor intensity, in good agreement with observed odor characteristics in pre-pubescent children and teenagers. Experiments with cultures on human and artificial sweat confirmed the ability of S. hominis and S. epidermidis to independently produce malodor with distinct odor characteristics. CONCLUSIONS: These results showcase the power of skin metagenomics to study host-microbial co-metabolic interactions, identifying distinct pathways for odor generation from sweat in pre-pubescent children and teenagers and highlighting key enzymatic targets for intervention.