Distribution Of Organic Acids Research Articles

Metabolome Comparison of Sichuan Dried Orange Peels (Chenpi) Aged for Different Years

Chuan chenpi is obtained by aging the peel of Citrus reticulata cv. ‘Dahongpao’, a traditional Chinese citrus variety. Chenpi has been used in traditional Chinese medicine since ancient times. It is believed that the longer the ripening period, the better the health properties. The composition of the metabolome of Chuan chenpi and how different aging periods affect it are not known. Current analysis was performed using Chuan chenpi aged for one (CR1), five (CR5) and ten (CR10) years. Initially, the total flavonoid and phenolic content were quantified, and then the global metabolomic profiles of CR1, CR5 and CR10 were studied. The total flavonoid and phenolic content increased significantly in CR5 compared to CR1 and then decreased in CR10. The metabolomic analyses led to the identification of 781 compounds belonging to more than 19 classes. Flavonoids and phenolic acids accounted for almost half (~48%) of the Chuan chenpi metabolome. Other major classes included amino acids (~8%), alkaloids (7.17%), organic acids (~7%), sugars (5.5%), nucleotides and derivatives (~5%), free fatty acids (3.33%) and other classes. The metabolite diversity of glycerol esters, terpenoids and stilbenes was constant during the three storage periods, whereas those of lignans, vitamins, coumarins, lipids and free fatty acids showed slight variations. The subclass distribution of phenylpropanoids, quinones, sphingolipids, and organic acids showed a decrease in diversity from CR1 to CR5, with CR10 showing a further decrease or remaining constant. Amino acids and derivatives, phenolic acids and flavonoids showed an increasing trend in the number of metabolites over the storage period. Compared to CR5, CR10 showed a higher number of differentially accumulated metabolites; in particular, flavonoids, phenolic acids and organic acids showed increased accumulation in CR10. In conclusion, the metabolome of Chuan chenpi is rich in flavonoids and phenols. Aging significantly affects the metabolome composition. Both CR5 and CR10 may be useful materials for health studies depending on the objectives of pharmacological use.

Tunisian Silybum Species: Important Sources of Polyphenols, Organic Acids, Minerals, and Proteins across Various Plant Organs.

Silybum marianum and Silybum eburneum are wild edible Mediterranean plants used in the human diet. This study presents the initial findings on the phytochemical characterization of Tunisian S. marianum and S. eburneum organs. It examined their mineral, sugar, organic acid, polyphenolic, and seed storage protein contents, as well as their antioxidant potential. In S. marianum, stems had high sodium and potassium contents, while the immature and mature seeds were rich in calcium and magnesium. However, S. eburneum had high potassium levels in stems and high sodium and calcium levels in the flowers. S. marianum showed substantial fructose variation among its organs. Conversely, S. eburneum exhibited significant heterogeneity in glucose, sucrose, and maltose levels across its organs, with maltose exclusively detected in the immature seeds. A notable organ-dependent distribution of organic acids was observed among the two species. Higher levels of phenolic contents were detected in both mature and immature seeds in both species compared to the other plant parts. The seeds possessed higher antioxidant activities than other plant organs. In both S. marianum and S. eburneum seeds, albumins and globulins were the predominant protein fractions. This study brings evidence supporting the important potential of Silybum organs as sources of nutrients with antioxidant properties for producing functional food.

Kinetics of fermentative production of propionic acid on a range of carbon and nitrogen sources using Acidipropionibacterium acidipropionici

Propionic acid is a well-known organic acid with widespread applications in food, chemical, and pharmaceutical industries, mainly produced by Acidipropionibacterium and Propionibacterium genera. In this work, Acidipropionibacterium acidipropionici is used to produce propionic acid from a range of carbon, and nitrogen sources. Their organic acid distribution differed significantly depending on the carbon sources used. Glycerol almost completely converted to propionic acid, whereas glucose produced significant amount of by-products. The product distribution of lactate was in between those carbon sources. The simultaneous use of two different carbon sources can speed up fermentation by up to 50%. The fastest propionic acid production rate was 0.564 gPA L−1 h−1 with combined use of glycerol and lactic acid. This was faster than the rates achieved with lactic acid and glucose (0.256 gPA L−1 h−1) and glucose and glycerol (0.317 gPA L−1 h−1) combinations. The concentration of the carbon source affects the fermentation rate, as increased osmotic pressure results in decreased μmax. The addition of biotin and pantothenate increased the rate of fermentation, also preventing pyruvic acid accumulation. Glucose gave the highest biomass yield among carbon sources, and yeast autolysate resulted in the highest product formation among nitrogen sources. A. acidipropionici can use ammonia as a nitrogen source but to a limited extent. Overall, A. acidipropionici is a versatile organism with the potential for industrial production of propionic acid due to its flexibility to use a range of carbon sources alone or in combination which can be tailored to achieve the desired end product.

Spatial and Temporal Distribution of Four Organic Acids during Post-Ripening of ‘Fenjiao’ Bananas Observed by Mass Spectrometry Imaging

Organic acids are among the primary substances affecting the flavor of ‘Fenjiao’ bananas. Several previous studies have characterized organic acids and their corresponding biosynthetic pathways in ‘Fenjiao’ bananas; however, chemical information about the spatial and temporal distributions of the organic acids in the bananas is absent. In this study, air flow-assisted desorption electrospray ionization mass spectrometry imaging (AFADESI-MSI) for analyzing organic acids in ‘Fenjiao’ bananas was developed. The organic acids in the peel and pulp of ‘Fenjiao’ bananas were detected and imaged in situ, and the spatial distribution of organic acids in banana fruit tissue slices were visualized. The results were validated by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The results showed that the MSI method can provide more accurate spatial and chemical localizations of the four primary organic acids (i.e., citric, malic, fumaric, and quinic acids) in the same tissues of ‘Fenjiao’ bananas. However, the quantification of the concentrations in different tissues is adversely affected by inaccuracy due to matrix effects. The in situ determination of the organic acids in ‘Fenjiao’ bananas can assist to understand the spatial and temporal distribution of organic acids in bananas, which provides a new method and idea to explore the biosynthesis and accumulation pattern of metabolites.

Visualizing the Distribution of Jujube Metabolites at Different Maturity Stages Using Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging.

Chinese jujube (also called Chinese date, Ziziphus jujuba Mill.) is an economically important tree in China and provides a rich source of sugars, vitamins, and bioactive components, all of which are indispensable and essential for the composition and participation in life processes of the human body. However, the location of these metabolites in jujube fruits has not been determined. This study applied matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to investigate the spatial distribution of sugars, organic acids, and other key components in jujube fruits at different developmental periods. Soluble sugars such as hexoses and sucrose/maltose significantly increase with fruit ripening, while organic acids show an overall trend of initially increasing and then decreasing. Procyanidins and rutin exhibit specific distributions in the fruit periphery and peel. These findings suggest that MALDI-MSI can be used to study the spatial distribution of nutritional components in jujube fruits, providing insights into the changes and spatial distribution of substances during jujube fruit development. This technique offers a scientific basis for jujube breeding, utilization, and production.

Autofermentation of alkaline cyanobacterial biomass to enable biorefinery approach

BackgroundCarbon capture using alkaliphilic cyanobacteria can be an energy-efficient and environmentally friendly process for producing bioenergy and bioproducts. The inefficiency of current harvesting and downstream processes, however, hinders large-scale feasibility. The high alkalinity of the biomass also introduces extra challenges, such as potential corrosion, inhibitory effects, or contamination of the final products. Thus, it is critical to identify low cost and energy-efficient downstream processes.ResultsAutofermentation was investigated as an energy-efficient and low-cost biomass pre-treatment method to reduce pH to levels suitable for downstream processes, enabling the conversion of cyanobacterial biomass into hydrogen and organic acids using cyanobacteria’s own fermentative pathways. Temperature, initial biomass concentration, and oxygen presence were found to affect yield and distribution of organic acids. Autofermentation of alkaline cyanobacterial biomass was found to be a viable approach to produce hydrogen and organic acids simultaneously, while enabling the successful conversion of biomass to biogas. Between 5.8 and 60% of the initial carbon was converted into organic acids, 8.7–25% was obtained as soluble protein, and 16–72% stayed in the biomass. Interestingly, we found that extensive dewatering is not needed to effectively process the alkaline cyanobacterial biomass. Using natural settling as the only harvesting and dewatering method resulted in a slurry with relatively low biomass concentration. Nevertheless, autofermentation of this slurry led to the maximum total organic acid yield (60% C mol/C mol biomass) and hydrogen yield (326.1 µmol/g AFDM).ConclusionAutofermentation is a simple, but highly effective pretreatment that can play a significant role within a cyanobacterial-based biorefinery platform by enabling the conversion of alkaline cyanobacterial biomass into organic acids, hydrogen, and methane via anaerobic digestion without the addition of energy or chemicals.

Visualized analysis of amino acids and organic acids in wheat caryopsis in response to multigenerational effects of elevated atmospheric CO2 concentration

The response of wheat to elevated atmospheric CO2 concentration (e[CO2]) within a single generation is being cumulatively studied, but multigenerational effects of e[CO2] on wheat is largely unknown. In this study, the emerging spatially resolved metabolomics was used to visualize the spatial distributions of amino acids and organic acids in wheat caryopsis exposed to multigenerational e[CO2]. These results showed that nine kinds of amino acids and three kinds of organic acids exhibited embryo-distribution pattern in wheat caryopsis under sequential atmospheric CO2 concentration (a[CO2]). Additionally, e[CO2] can induce nonuniformly spatial distribution of amino acids and organic acids. Further inspection of the differential accumulation of amino acids in embryo/endosperm under multigenerational e[CO2] exposure indicated that the abundance of valine, glutamine, glutamic acid and histidine in embryo was decreased by multigenerational e[CO2] exposure, whereas abundance of lysine, aspartic acid and glutamic acid in endosperm showed different trends. Multigenerational e[CO2] exposure decreased the abundance of ascorbic acid and cis-aconitic acid, regardless of regions, while increased the abundance of malic acid in endosperm. It was suggested that the long-term e[CO2] cause inconsistent changes in embryo and endosperm, which may lead to potential impacts on human dietary health and crop offspring vigor.

In situ analysis of volatile oil in Angelica sinensis roots by fluorescence imaging combined with mass spectrometry imaging

In this study, the spatial distribution and accumulation dynamics of volatile oil in Angelica sinensis roots was realized by fluorescence imaging combined with mass spectrometry imaging. The laser scanning confocal microscopy was used to determine the optimal excitation wavelength and the fluorescent stability of volatile oil in the sections of Angelica sinensis roots. The results demonstrated that 488 nm was the most suitable excitation wavelength for the identification and quantitative analysis of volatile oil. It was observed that volatile oil accumulated in the oil chamber of the phelloderm and secondary phloem, and the oil canal of the secondary xylem. The results also indicated that there were differences in content during different periods. Furthermore, the MALDI-TOF-MSI technology was used to study the spatial distribution and compare the chemical compositions of different parts of Angelica sinensis roots during the harvest period. A total of 55, 49, 50 and 30 compounds were identified from the head, body, tail of the root and root bark, respectively. The spatial distribution of phthalides, organic acids and other compounds were revealed in Angelica sinensis roots. The method developed in this study could be used for the in situ analysis of volatile oil in Angelica sinensis roots.

Enrichment of short-chain organic acids transferred to submicron sea spray aerosols

Organic acids, considered to be a substantial component of the marine carbon cycle, can enter the atmosphere through sea spray aerosol (SSA) and further affect the climate. Despite their importance, the distribution and mixing state of organic acids in SSA over the marine boundary layer are poorly understood and therefore need more investigation. Here, we have used ion chromatography (IC) in anion mode to measure short-chain organic acids concentrations in SSA collected throughout a custom-made SSA simulation chamber. The enrichment behavior and morphology of monocarboxylic acids (MAs, C1–8) and dicarboxylic acids (DAs) in submicron SSA were studied in seawater. We found that with MAs addition, the number concentration and mass concentration of SSA particles decreased gradually for C5–8 MAs, whereas they weakly varied with DAs addition due to the fact that carboxyl groups at both ends of DAs increased the surface tension of seawater. Moreover, the target compounds in submicron SSA displayed a surface activity-dependent enrichment behavior, where seawater with stronger surface activity, such as that containing MAs with >5 carbons, was more enriched in SSA in comparison to seawater with weaker surface activity. MAs with chain length <5 carbons were slightly enriched in SSA, whereas the enrichment factor (EF) of C5–8 MAs further increased with increasing chain length. These findings are of utmost importance in further understanding and quantifying the contribution of organic matter to SSA, which is crucial for assessing the atmosphere feedback of the marine carbon cycle. Main finding of the workSurface tension of seawater is the key factor affecting the enrichment of short-chain organic acids in SSA.

Summertime High Abundances of Succinic, Citric, and Glyoxylic Acids in Antarctic Aerosols: Implications to Secondary Organic Aerosol Formation

AbstractObservations of organic compounds associated with natural sources are scarce in Antarctica, which limits our understanding of their sources and formation processes over the pristine region. Summertime Antarctic PM10 samples collected from Bharati station were studied for a homologous series of dicarboxylic acids (C2‐C12), ω‐oxoacids (C2‐C9), α‐dicarbonyls (C2‐C3) as well as citric and pyruvic acids by employing a water‐extraction followed by dibutyl ester derivatization technique and analyzed using capillary gas chromatography (GC). Results show that succinic (C4) and citric acids are the foremost abundant among the measured organic acids followed by glyoxylic (ωC2), azelaic (C9), and adipic (C6) acids. Such a typical molecular distribution of organic acids suggests the dominance of natural sources over the Antarctic. Two distinct air masses arrived from different altitudes, high and low altitude‐troposphere (HTAs and LTAs), showed a significant difference in mass concentrations of organic acids with higher values in LTAs. Total diacids‐C accounted for ∼9% of total carbon in HTAs, which is linked to chemical aging during long‐range transport. The higher abundance of C4 and citric acids are likely produced through secondary photooxidation of marine‐derived organic precursors, such as unsaturated fatty acids, phenolic, and biogenic isoprene compounds enriched in sea‐surface microlayer, via sea‐to‐air emission as confirmed by the significant (p &lt; 0.05) correlations among the organic tracer compounds. Minor concentrations of oxalic and malonic (C2 and C3) acids were attributed to photo iron‐complex reactions in the aqueous‐phase atmosphere. These findings may help in reducing model uncertainties and present new insights into the secondary formation of organic aerosols in the polar environment.

Potential of multiparametric characterization of foodstuffs by nuclear magnetic resonance to better predict microbial behavior.

Numerous predictive microbiology models have been proposed to describe bacterial population behaviors in foodstuffs. These models depict the growth kinetics of particular bacterial strains based on key physico-chemical parameters of food matrices and their storage temperature. In this context, there is a prominent issue to accurately characterize these parameters, notably pH, water activity (aw ), and NaCl and organic acid concentrations. Usually, all these product features are determined using one destructive analysis per parameter at macroscale (>5g). Such approach prevents an overall view of these characteristics on a single sample. Besides, it does not take into account the intra-product microlocal variability of these parameters within foods. Nuclear magnetic resonance (NMR) is a versatile non-invasive spectroscopic technique. Experiments can be recorded successively on a same collected sample without damaging it. In this work, we designed a dedicated NMR approach to characterize the microenvironment of foods using 10-mg samples. The multiparametric mesoscopic-scale approach was validated on four food matrices: a smear soft cheese, cooked peeled shrimps, cold-smoked salmon, and smoked ham. Its implementation in situ on salmon fillets enabled to observe the intra-product heterogeneity and to highlight the impact of process on the spatial distribution of pH, NaCl, and organic acids. This analytical development and its successful application can help address the shortcomings of monoparametric methods traditionally used for predictive microbiology purposes.

Spatial distribution of sugars, organic acids, vitamin C, carotenoids, tocopherols, 6-methoxymellein, polyacetylenic compounds, polyphenols and terpenes in two orange Nantes type carrots (Daucus carota L.)

In this study, the main primary and secondary metabolites were analyzed in various parts of two orange carrots. Results clearly indicate levels vary considerably between tissues and sections, and also highlight the importance of adopting standardized sampling methods when determining quality attributes in carrot. Peel was richer in citric acid, γ-tocopherol, 6-methoxymellein, falcarindiol, and most polyphenols and terpenes than other tissues, and poorer in sugars, α-tocopherol and falcarinol. Phloem was richer in falcarindiol acetate, but poorer in malic acid. Contrary to α- and β-carotene, lutein was mainly localized in xylem. Sucrose, carotenoids, α-tocopherol and falcarindiol acetate significantly decreased from the top sections of tissues to the bottom ones. Citric acid, 6-methoxymellein, falcarindiol and most terpenes showed similar trends in peel. In contrast, reducing sugars showed an increasing profile in tissues with highest levels in the bottom sections. Most polyphenols showed similar patterns in peel, and malic acid in phloem. Falcarinol contents decreased from the top sections of phloem to the bottom ones but increased in xylem. No clear trend was observed for γ-tocopherol and ascorbic acid.

Modeling of low salinity waterflooding in carbonates: Effect of rock wettability and organic acid distribution

Carbonate reservoirs hold a substantial amount of our existing oil reserves. However, waterflood recovery from these reservoirs is often low due to their oil-wet nature. Recent studies have shown that oil recovery from oil-wet carbonate reservoirs can be increased by wettability alteration using low salinity brines having carefully modified ionic compositions. In this study, we developed a multiphase, multicomponent, finite-difference reservoir simulator and incorporated an improved mechanistic model to model low salinity waterflood in carbonates. The model considers key geochemical reactions relevant to low salinity waterflooding as reported by many authors recently. However, our modeling approach differs in two ways. Firstly, our model assumes that geochemical reactions of injected brines with the rock take place only on water-wet surfaces of these rocks and at the three-phase contact line; compared to other existing models that consider reactions to occur on the entire rock surface for oil-wet rocks. Secondly, previous models consider organic acids as a single species. In reality, oil is likely to have a mixture of different organic acids of different polarity, chain length, etc. In our model, we consider the oil to have a mixture of different organic acids and studied its impact on wettability alteration and oil recovery. Using this model, single phase and oil recovery experiments reported in the literature were modeled. The effect of rock wettability on geochemical reactions of low salinity brines with carbonate rocks was studied. Similarly, the effect of organic acid distribution on wettability alteration and oil recovery was investigated. Our simulation results showed that the extent of reaction of low salinity brines with carbonate rocks decreased as the rock became more oil-wet due to a decrease in reactive surface area. For example, less delay in effluent sulfate ions was observed in case of oil-wet rocks. The water-wet regions grew as a result of wettability alteration at the three-phase contact line. The initial wettability, extent of wettability alteration, and oil recovery profiles were dependent on the organic acid distribution. Furthermore, the inclusion of only key geochemical reactions (dolomitization, sulfate adsorption, and anhydrite dissolution/precipitation) were found to be reasonable for modeling various experiments reported in the literature. The proposed model will help in improving our understanding of mechanisms responsible for wettability alteration.

Sugar and organic acid availability modulate soil diazotroph community assembly and species co-occurrence patterns on the Tibetan Plateau.

Metabolites can mediate species interactions and the assembly of microbial communities. However, how these chemicals relate to the assembly processes and co-occurrence patterns of diazotrophic assemblages in root-associated soils remains largely unknown. Here, we examined the diversity and assembly of diazotrophic communities and further deciphered their links with metabolites on Tibetan Plateau. We found that the distribution of sugars and organic acids in the root-associated soils was significantly correlated with the richness of diazotrophs. The presence of these two soil metabolites explains the variability in diazotrophic community compositions. The differential concentrations of these metabolites were significantly linked with the distinctive abundances of diazotrophic taxa in same land types dominated by different plants or dissimilar soils by same plants. The assembly of diazotrophic communities is subject to deterministic ecological processes, which are widely modulated by the variety and amount of sugars and organic acids. Organic acids, for instance, 3-(4-hydroxyphenyl)propionic acid and citric acid, were effective predictors of the characteristics of diazotrophic assemblages across desert habitats. Diazotrophic co-occurrence networks tended to be more complex and connected within different land types covered by the same plant species. The concentrations of multiple sugars and organic acids were coupled significantly with the distribution of keystone species, such as Azotobacter, Azospirillum, Bradyrhizobium, and Mesorhizobium, in the co-occurrence network. These findings provide new insights into the assembly mechanisms of root-associated diazotrophic communities across the desert ecosystems of the Tibetan Plateau.Key points• Soil metabolites were significantly linked to the diversity of diazotrophic community.• Soil metabolites determined the assembly of diazotrophic community.• Sugars and organic acids were coupled mainly with keystone species in networks.

Visualizing the spatial distribution of metabolites in Clausena lansium (Lour.) skeels using matrix-assisted laser desorption/ionization mass spectrometry imaging

Clausena lansium (Lour.) Skeels (Rutaceae) is a natural bioactive plant. Its roots, stems, leaves, and seeds are widely used in Chinese traditional and folk medicine. Although the characterization and functional analysis of bioactive components in Clausena lansium (Lour.) Skeels has been widely reported, the spatial distribution of these compounds within the main plant tissues remains undefined. Here, we adopted matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) to reveal the spatial distribution of active alkaloids, coumarins, sugars and organic acids in C. lansium. Using a combined wet and dry matrix covering method to enhance sensitivity, we detected alkaloids throughout the fruit including 3-methylcarbazole and murrastinine which were especially rich in the kernel tissues but were restricted to the stem xylem and medulla and in the leaf epidermal region. Interestingly, murrayanine and heptaphylline were mainly found in pulp tissues with very low content in the stems and leaves while girinimbine was only distributed within the outer kernel skin. Coumarins were mainly distributed in the fruit pericarp and leaf vein tissues but with no clear spatial specificity in stems. Lastly, hexoses were mainly evident in the fruit pulp, although sucrose was also found in the pericarp, pulp, and pulp fibers with citric acid being distributed throughout the fruit. The accurate spatial and chemical information obtained provides new insights into the specific accumulation of metabolites in individual tissues.

Spatial distribution of apoplastic antioxidative constituents in maize root.

Apoplastic antioxidative constituents (enzymes, primary and secondary metabolites, ROS) from different root zones of hydroponically grown maize (Zea mays L.) were investigated using a noninvasive isolation procedure: filter strip method. Filter strips were placed at specific positions on the root surface: apical zone (tip) and basal zone (base) to absorb apoplastic fluid. Three major classes of low-weight metabolites (organic acids, sugars, and phenolics) have been identified by HPLC-ECD. The longitudinal distribution of sugars and organic acids had the same pattern: higher concentration in the tip than the base, while it was vice versa for phenolics. The specific activities of guaiacol peroxidase, superoxide dismutase, and ascorbate peroxidase were higher in the apoplastic fluid from the root base than the tip, and their different isoforms were separated by isoelectric focusing. Electron paramagnetic resonance (EPR) spectroscopy coupled with the spin-trapping method using DEPMPO showed a persistent generation of hydroxyl radical in the root tip. In vivo EPR imaging of the whole maize root with membrane-permeable and impermeable aminoxyl spin-probes, enabling real-time detection of ROS formation within and outside the membranes, demonstrated ROS accumulation on the root surface, while endodermis and central cylinder were ROS free. For the first time in plant research, 2D EPR images enabled the direct demonstration of site-specific free radical production along the root. Highly sensitive analytical techniques combined with the filter strips, as a non-invasive tool, have increased our knowledge of metabolic processes occurring in the apoplast and their spatial-temporal changes in small regions of the intact root tissue.

Distributions of eight bioactive components in rat tissues administered Marsdenia tenacissima extract orally detected through UPLC-MS/MS.

Marsdenia tenacissima (Roxb.) Wight et Arn. (M. tenacissima) is considered an anticancer medicine in traditional Chinese medicine, which is extensively used in clinical application since it has great therapeutic effects. Currently, although a number of articles have examined M. tenacissima in terms of its pharmacology and quality control, few have investigated the in vivo mechanism of M. tenacissima active ingredients. Previously, we have studied the pharmacokinetics of eight active ingredients after oral administration of M. tenacissima extracts in rat plasma. This study constructed a new scientific ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) approach to simultaneously quantify the contents of tenacissosides B, G, H and I, cryptochlorogenic acid, chlorogenic acid, neochlorogenic acid and caffeic acid in rats orally administered M. tenacissima extract. The proposed approach was successfully used for investigating the distributions of those eight analytes in rat tissues, with digoxin being used as an internal control. The Eclipse Plus C18 RRHD column was used for determination at a column temperature of 30°C. The mobile phase system consisted of acetonitrile and water (supplemented with 0.1% formic acid) under optimal gradient elution conditions. Afterwards, this approach was validated according to the requirements for the analysis of biological samples developed by the US Food and Drug Administration, including precision, accuracy, stability and matrix effects. Based on tissue distribution analysis, those eight analytes showed rapid distribution within all the tested tissues. With regard to organic acid distribution, it followed the order stomach > liver > kidney > small intestine > lung > spleen > heart, whereas the four steroids followed the order stomach > lung > spleen > small intestine > liver > kidney > heart. The present study lays the theoretical foundation for the use and development of M. tenacissima in clinical practice.

High resolution-&lt;sup&gt;1&lt;/sup&gt;Н NMR spectroscopy of oral liquid in young patients with wedge-shaped lesions

Aim. The comparison of saliva 1Н NMR spectra in patients with wedge-shaped lesions before and after treatment.Materials and methods. Saliva as a study material was taken from patients with wedge-shaped lesions before and after treatment. The treatment method was remineralizing therapy that included the use of the oral rinse containing zinchydroxyapatite. 1Н NMR spectroscopy was chosen as an investigation method.Results. In most cases it is noted that after treatment the content of propionic and butyric acids was on the rise in relation of acetic acid. Overall concentration of 1Н protons didn't change significantly.Conclusions. 1Н NMR spectra analysis shows organic acid distribution in oral liquid before and after treatment, which helps to evaluate its response.

Simple Derivatization-Gas Chromatography-Mass Spectrometry for Fatty Acids Profiling in Soil Dissolved Organic Matter.

Dissolved organic matter is an important component of the global carbon cycle that allows the distribution of carbon and nutrients. Therefore, analysis of soil dissolved organic matter helps us to better understand climate change impacts as it is the most dynamic and reactive fraction in terrestrial ecosystems. Its characterization at the molecular level is still challenging due to complex mixtures of hundreds of compounds at low concentration levels in percolating water. This work presents simple methods, such as thermochemolysis– or derivatization–gas chromatography, as an alternative for the analysis of fatty acids in dissolved organic matter without any purification step. The variables of the protocols were examined to optimize the processing conditions for the C9–C18 range. As a proof of concept, fatty acid distributions of soil percolating water samples from a long-term field experiment were successfully assessed. The variability of dissolved organic acid distributions was pronounced through depth profile and soil treatment but no major change in composition was observed. However, although the optimization was done from C9 to C18, detection within the C6-C32 fatty acids range was performed for all samples.

The role of exogenous oxygen in organic acid generation in deep reservoirs of petroleum-producing basins: Progress and prospects

The source, yield, and distribution of organic acids in oilfield waters in petroleum-producing basins have not been satisfactorily explained by previous studies that have focused on oxygen-containing functional groups in kerogen as the major source of such acids. This study reviews four possible mechanisms by which exogenous oxygen can participate in petroleum or organic acid generation. Biodegradation and mineral oxidation generate organic acids in oilfield waters, leading to an increase in the oxygen content of altered oils, which then have greater potential for producing organic acids. Hydrolytic disproportionation reaction and thermochemical sulfate reduction reactions at high temperatures lead to the in situ generation and accumulation of organic acids in deep reservoirs. The incorporation of exogenous oxygen increases the yield and expands the distribution of organic acids in reservoirs at various depths. The acids derived from exogeneous oxygen play critical roles in the development and preservation of deep reservoirs. Further research is required to determine the volumes and compositions of organic acids produced by these reactions, and to further understand the role of organic acids in the alteration of deep reservoirs under more realistic conditions.