Acid In Biological Material Research Articles

Carbon-13-isotopomics and metabolomics of fatty acids from triacylglycerols: overcoming the limitations of GC-C-IRMS for short- and medium-acyl chains.

Carbon-13 isotopomics of triacylglycerol (TAG) fatty acids or free fatty acids in biological matrices holds considerable potential in food authentication, forensic investigations, metabolic studies, and medical research. However, challenges arise in the isotopic analysis of short- and medium-chain (C4 to C10) fatty acid methyl esters (SMCFAMEs) through gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). The high volatility of these esters results in losses during their preparation, leading to isotopic fractionation. Moreover, the methoxy group added to acyl chains requires the correction of δ13C values, thereby increasing the uncertainty of the final results. Analyzing free fatty acids (FFAs) addresses both issues encountered with SMCFAMEs. To achieve this objective, we have developed a new protocol enabling the isotopomics of individual fatty acids (FAs) by GC-C-IRMS. The same experiment also provides the FA profile, i.e., the relative percentage of each FA in the TAG hydrolysate or its concentration in the studied matrix. The method exhibited high precision, as evidenced by the repeatability and within-lab reproducibility of results when tested on TAGs from both animal and vegetal origins. Compared to the analysis of FAMEs by GC-C-IRMS, the current procedure also brings several improvements in alignment with the principles of green analytical chemistry and green sample preparation. Thus, we present a two-in-one method for 13C-isotopomic and metabolomic biomarker quantitation within quasi-universal TAG compounds, encompassing the short- and medium-acyl chains.

Comprehensive profiling of amino acids and derivatives in biological samples: A robust UHPLC-MS/MS method for investigating acute lung injury

The severe respiratory dysfunctions associated with acute lung injury (ALI) and its sequelae have a high morbidity and mortality rate, are multifactorial, and lack a viable treatment. Considering the critical function that amino acids and derivatives play in the genesis of illnesses and the regulation of metabolic processes, monitoring the levels of metabolites associated with amino acids in biological matrices is necessary and interesting to study their pathological mechanisms. Exploring the dynamics of amino acids and derivatives level and searching for biomarkers provides improved clinical ideas for the diagnosis and treatment of ALI. Therefore, we developed an ultra-high-performance liquid chromatography-electrospray tandem mass spectrometry (UHPLC-MS/MS) method that can simultaneously determine the amino acid and derivatives metabolic levels to study amino acid profiles in different biological samples to facilitate clinical research of ALI. In this study, 48 amino acids and derivatives, including neurotransmitters, polyamines, purines, and other types, were quantified simultaneously in a fast, high-throughput, sensitive, and reliable manner within a 15-minute run time without derivatization. No relevant studies have been reported to quantify these 48 amino acid metabolites in three biological samples simultaneously. Satisfactory linearity (R > 0.995), inter-day and intra-day accuracy (85.17–112.67 % and 85.29–111.60 %, respectively), inter-day and intra-day precision (RSD < 13.80 % and RSD < 12.01 %, respectively), matrix effects (81.00 %–118.00 %), recovery (85.09 %–114.65 %) and stability (RSD < 14.72 %) were all demonstrated by the optimized method's successful validation for all analytes. In addition, the suggested method was effectively implemented in plasma, urine, and lung tissue from normal mice and mice with ALI, with the aim of finding potential biomarkers associated with ALI. Potential biomarkers were screened through multivariate statistical analysis and volcanic map analysis, and the changes of markers in ALI were again identified through heat map analysis and correlation analysis with biochemical indicators, which provided ideas and references for subsequent mechanism studies. Here, the technique created in this work offers a quick and dependable way to perform an integrated analysis of amino acids in a variety of biological materials, which can provide research ideas for understanding the physiopathological state of various diseases.

Malícia honey (Mimosa quadrivalvis L.) produced by the jandaíra bee (Melipona subnitida D.) improves anxious-like behaviour and has anti-adiposity effect in cafeteria diet-induced obese rats

This study evaluated the anti-adiposity and anxiolytic effects of malícia honey (MH) on obese rats. A total of 40 male Wistar rats were initially randomized into four groups: healthy (HG); obese (OG); and healthy (HGH) and obese (OGH) both treated with malícia honey by gavage (1000 mg/kg). The rats consumed a control or cafeteria diet for 16 weeks. Body weight, food intake, adiposity index, anxious-like behaviour and concentration of organic acids in the brain, intestine and faeces were analysed. Histological analyses were performed on adipose tissue and brain. MH showed procyanidin B1 and B2, epicatechin, and naringenin as the main polyphenols. The OGH had lower caloric intake (18 %), body weight (12 %) and lower adipocyte area compared to the OG. MH increased organic acids in biological materials and prevented the appearance of ischemic neurons. MH had an anti-adiposity effect, protected the nerve tissue and reversed anxious-like behaviour in obesity-induced rats.

Анализ лабораторной диагностики хламидиоза животных и птицы в Российской Федерации за 2019–2021 гг.

Chlamydia infection causes significant economic damage to various branches of animal husbandry and poultry farming. In the system of veterinary and sanitary measures, it is important to detect the pathogen as early and reliably as possible in various forms of the disease. For this purpose, a number of laboratory methods of direct and indirect diagnosis of chlamydia have been developed over the past years. The article analyzes the results of laboratory tests for chlamydia in state veterinary laboratories for 2019–2021, as well as cases of positive results in the study of biological and pathological materials from animals, including birds. During the analyzed period, 2 750 726 samples of material from animals, including birds, were received by state veterinary laboratories for research on chlamydia, of which 2 645 605 (96,7 %) samples were examined by serological methods, specific antibodies were detected in 0,4 % of blood serum from animals (except birds). Positive results of serological tests require mandatory confirmation by methods of direct detection of chlamydia, their antigens, nucleic acids in biological material. The genetic material of chlamydia during polymerase chain reaction studies was detected in 1 % of samples of biological and pathological material from animals, including birds.

Measuring Conjugated Linoleic Acid (CLA) Production by Bifidobacteria.

The biological significance of conjugated fatty acids (CFAs) has been linked to positive health effects based on biomedical, in vitro, and clinical studies. Of note, conjugated linoleic acids (CLAs) are the most widely characterized fatty acids as geometric isomers cis-9,trans-11 and trans-10,cis-12CLA occur naturally in ruminant fats, dairy products, and hydrogenated oils. Concerning CLAs, it is known that bacterial biohydrogenation, a process whereby ruminal bacteria or starter cultures of lactic acid bacteria have the ability to synthesize CLA by altering the chemical structure of essential fatty acids via enzymatic mechanisms, produces a multitude of isomers with desirable properties. Bifidobacterium species are classed as food grade microorganisms and some of these strains harness molecular determinants that are responsible for the bioconversion of free fatty acids to CLAs. However, molecular mechanisms have yet to be fully elucidated. Reports pertaining to CLAs have been attributed to suppressing tumor growth, delaying the onset of diabetes mellitus and reducing body fat in obese individuals. Given the increased attention for their bioactive properties, we describe in this chapter the qualitative and quantitative methods used to identify and quantifyCLA isomers produced by bifidobacterial strains in supplemented broth media. These approaches enable rapid detection of potential CLA producing strains and accurate measurement of fatty acids in biological matrices.

POE Immunoassay: Plate-based oligonucleotide electro-chemiluminescent immunoassay for the quantification of nucleic acids in biological matrices

Oligonucleotide therapeutics use short interfering RNA (siRNA) or antisense oligonucleotide (ASO) molecules to exploit endogenous systems—neutralizing target RNA to prevent subsequent protein translation. While the potential clinical application is vast, delivery efficiency and extrahepatic targeting is challenging. Bioanalytical assays are important in building understanding of these complex relationships. The literature currently lacks description of robust and sensitive methods to measure siRNA and ASOs in complex biological matrices. Described herein is a non-enzymatic hybridization-based immunoassay that enables quantification of individual siRNA strands (antisense or sense) in serum, urine, bile, and liver and kidney homogenates. Assay utility is also demonstrated in ASOs. The assay improves upon previous works by abolishing enzymatic steps and further incorporating Locked Nucleic Acid (LNA) nucleotide modifications to increase analyte hybridization affinity and improve sensitivity, specificity, and robustness. We report an assay with an ultrasensitive dynamic range of 0.3 to 16,700 pM for siRNA in serum. The assay was submitted to full qualification for accuracy and precision in both serum and tissue matrices and assay performance was assessed with single and mixed analytes. The reliable LNA-hybridization-based approach removes the need for matrix sample extraction, enrichment or amplification steps which may be impeded by more advanced chemical modifications.

The Study of Viral RNA Diversity in Bird Samples Using De Novo Designed Multiplex Genus-Specific Primer Panels.

Advances in the next generation sequencing (NGS) technologies have significantly increased our ability to detect new viral pathogens and systematically determine the spectrum of viruses prevalent in various biological samples. In addition, this approach has also helped in establishing the associations of viromes with many diseases. However, unlike the metagenomic studies using 16S rRNA for the detection of bacteria, it is impossible to create universal oligonucleotides to target all known and novel viruses, owing to their genomic diversity and variability. On the other hand, sequencing the entire genome is still expensive and has relatively low sensitivity for such applications. The existing approaches for the design of oligonucleotides for targeted enrichment are usually involved in the development of primers for the PCR-based detection of particular viral species or genera, but not for families or higher taxonomic orders. In this study, we have developed a computational pipeline for designing the oligonucleotides capable of covering a significant number of known viruses within various taxonomic orders, as well as their novel variants. We have subsequently designed a genus-specific oligonucleotide panel for targeted enrichment of viral nucleic acids in biological material and demonstrated the possibility of its application for virus detection in bird samples. We have tested our panel using a number of collected samples and have observed superior efficiency in the detection and identification of viral pathogens. Since a reliable, bioinformatics-based analytical method for the rapid identification of the sequences was crucial, an NGS-based data analysis module was developed in this study, and its functionality in the detection of novel viruses and analysis of virome diversity was demonstrated.

Quantification of Sugars and Organic Acids in Biological Matrices Using GC-QqQ-MS.

Gas chromatography coupled with triple quadrupole mass spectrometry (GC-QqQ-MS) can be used to accurately quantify endogenous small molecules extracted from biological samples such as plants and human fluids including sera and urine. In order to quantify primary metabolites typically from central carbon metabolism such as sugars from glycolysis and the pentose phosphate pathway; and organic acids involved in the tricarboxylic acid (TCA) cycle; polar endogenous metabolites must be extracted from the samples of interest, chemically derivatized and quantified against a linear calibration curve to a corresponding authentic standard. This chapter describes how to quantify a combination of 48 primary metabolites belonging to classes of sugars, sugar alcohols, sugar acids, sugar phosphates, and organic acids using a robust, optimized, multiple reaction monitoring (MRM)-based GC-QqQ-MS method.

Fast Fatty Acid Analysis by Core-Shell Reversed-Phase Liquid Chromatography Coupled to Evaporative Light-Scattering Detector

A high-performance liquid chromatography analysis method with an evaporative light-scattering detector has been developed for the separation and quantitative analysis of free fatty acids in biological matrices. Core-shell reversed-phase high-performance liquid chromatography separation of 10 free fatty acids is achieved within 10.5 min using a methanol/water (0.05% trifluoroacetic acid) eluent gradient. After optimization, the drift tube and nebulization temperature of the evaporative light-scattering detector was set at 35°C, nitrogen flow-rate at 1.1 standard liter per minute and column temperature at 25°C. All calibration curves showed good regression (r2 > 0.9975). A validation procedure following the International Conference on Harmonisation guidelines was implemented to certify the method. Relative standard deviations did not exceed 1.5% and 4.25% for repeatability and reproducibility respectively.

Hollow fiber–stir bar sorptive extraction and microwave assisted derivatization of amino acids in biological matrices

A kind of solid phase microextraction configuration combining the principles of hollow fiber solid phase microextraction (HF–SPME) and stir bar sorptive extraction (SBSE) is presented. The main feature of HF–SBSE is the use of microporous hollow fiber acting as the carrier and filter, while a thin stainless steel wire and silica microspheres in the lumen of hollow fiber respectively acting as the magnetic stirrer and the dispersed sorbents for the collection and extraction of the target analytes, thus affording extraction process like SBSE. Moreover, the prepared hollow fiber stir bar was applied to direct microextraction and microwave assisted derivatization with N,O–Bis(trimethylsilyl)trifluroacetamide (BSTFA) of four amino acids in rats’ urine and cerebrospinal fluid followed by gas chromatography mass spectrometric analysis. The limits of detection for four amino acids were found to be in the range of 0.0003–0.017μgmL−1, and all the analytes did not exhibit any lack of fit. The extraction recoveries using HF–SBSE techniques ranged from 71.8% to 102.3%. The results indicated that hollow fiber stir bar sorptive extraction was a promising technique for the enrichment and direct derivatization of analytes extracted from biological matrices without sample clean–up.

Simultaneous analysis of d-alanine, d-aspartic acid, and d-serine using chiral high-performance liquid chromatography-tandem mass spectrometry and its application to the rat plasma and tissues

A highly sensitive and selective chiral LC-MS/MS method for d-alanine, d-aspartic acid and d-serine has been developed using the precolumn derivatization reagents, 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AccQ-Tag) or p-N,N,N-trimethylammonioanilyl N'-hydroxysuccinimidyl carbamate iodide (TAHS). The thus N-tagged enantiomers of the derivatized amino acids were nicely separated within 20min using the cinchona alkaloid-based zwittterionic ion-exchange type enantioselective column, Chiralpak ZWIX(+). The selected reaction monitoring was applied for detecting the target d-amino acids in biological matrices. By using the present chiral LC-MS/MS method, the three d-amino acids and their l-forms could be simultaneously determined in the range of 0.1–500nmol/mL. Finally, the technique was successfully applied to rat plasma and tissue samples.

THE USE OF HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY AS SCREENING TECHNIQUE FOR PECTIN AND PECTIN SUBSTANCES OF DIETARY FIBERS

The peak of the unspecified compound of quantitative analysis of organic acids in biological materials by using high-performance liquid chromatography was identified. This peak corresponded to polygalacturonic acid. A High-performance liquid chromatographic method was developed to identify and quantify of water soluble pectin fraction and insoluble pectin fraction, galacturonic acid and polygalacturonic acid. The method based on the extraction of free water soluble fraction with phosphate buffer (pH 4.8) or with 0.01 N phosphoric acid and on the acid hydrolysis of insoluble pectin fraction in presence 0.1 N HNO3. The pectin fractions were separated and determined on a C610H column using elution with 0.01 N phosphoric acids and ultraviolet detection at 210 nm. Galacturonic acid and polygalacturonic acid were used as internal standard. The calibration curves were presented for each of the standards. The determinations were performed in the linear range of 0.04÷0.17% w/v for both pectin fractions. Proposed procedure can considered as a rapid method for quantitative pectin determination in the food, food nutrition’s food, and pharmaceutical agents.

Determination of glutamic acid in biological material by capillary electrophoresis

The conditions for the identification and determination of Glutamic acid by capillary zone electrophoresis without their preliminary derivatization have been optimized. The effect of concentration of buffer electrolyte and pH on determination of Glutamic acid has been investigated. It is shown that the 5 Mm borate buffer concentration and a pH 9.15 are optimal. Quantitative determination of glutamic acid has been carried out using a linear dependence between the concentration of the analyte and the area of the peak. The accuracy and reproducibility of the determination are confirmed by the method "introduced - found". Glutamic acid has been determined in the placenta homogenate. The duration of analysis doesn't exceed 30 minutes. The results showed a decrease in the level of glutamic acid in cases of pregnancy complicated by placental insufficiency compared with the physiological, and this fact allows to consider the level of glutamic acid as a possible marker of complicated pregnancy.

Quantification and Mass Isotopomer Profiling of α-Keto Acids in Central Carbon Metabolism

Mass spectrometry has been established as a powerful and versatile technique for studying cellular metabolism. Applications range from profiling of metabolites to accurate quantification and tracing of stable isotopes through the biochemical reaction network. Despite broad coverage of central carbon metabolism, most methods fail to provide accurate assessments of the α-keto acids oxaloacetic acid, pyruvate, and glyoxylate because these compounds are highly reactive and degraded during sample processing and mass spectrometric measurement. We present a derivatization procedure to chemically stabilize these compounds readily during quenching of cellular metabolism. Stable derivatives were analyzed by ultrahigh pressure liquid chromatography coupled tandem mass spectrometry to accurately quantify the abundance of α-keto acids in biological matrices. Eventually, we demonstrated that the developed protocol is suited to measure mass isotopomers of these α-keto acids in tracer studies with stable isotopes. In conclusion, the here described method fills one of the last technical gaps for metabolomics investigations of central carbon metabolism.

A rapid method for the determination of free alpha-amino acids in pea (Pisum sativum) using ultra high performance liquid chromatography-high resolution accurate mass-mass spectrometry

The analysis of alpha-amino acids in biological matrices usually requires time-consuming ion exchange liquid chromatography with post column derivatisation.

Strategies for quantitation of endogenous adenine nucleotides in human plasma using novel ion-pair hydrophilic interaction chromatography coupled with tandem mass spectrometry

We present here a novel and highly sensitive ion-pair hydrophilic interaction chromatography–tandem mass spectrometry (IP–HILIC–MS/MS) method for quantitation of highly polar acid metabolites like adenine nucleotides. A mobile phase based on diethylamine (DEA) and hexafluoro-2-isopropanol (HFIP) and an aminopropyl (NH2) column were applied for a novel chromatographic separation for the determination of AMP, ADP and ATP in biological matrices. This novel IP–HILIC mechanism could be hypothesized by the ion-pairing reagent (DEA) in the mobile phase forming neutral and hydrophilic complexes with the analytes of polar organic acids. The IP–HILIC–MS/MS assay for adenine nucleotides was successfully validated with satisfactory linearity, sensitivity, accuracy, reproducibility and matrix effects. The lower limit of quantitation (LLOQ) at 2.00ng/mL obtained for ATP showed a least 10-fold higher sensitivity than previous LC–MS/MS assays except nano-LC–MS/MS assay. In summary, this novel IP–HILIC–MS/MS assay provides a sensitive method for nucleotides bioanalysis and shows great potential to determine a number of organic acids in biological matrices.

Separation and sensitive detection of D‐amino acids in biological matrices

The increase in our understanding of D-amino acid function and distribution in mammals is in many ways a result of the initial development of sensitive enantioselective separation strategies that allow for quantification in real biological samples. This article reviews progress on the development of chiral selective separation and detection of D-amino acids including enzyme-based microbiosensors, GC/MS, HPLC/fluorescence, HPLC/MS-MS, cEKC/fluorescence, and MEKC/fluorescence. Only methods capable of analyzing D-isomers in biological matrices are given here and significant effort is made to highlight approaches that offer speed, resolution, high sensitivity, and versatility.

Determination of free- and protein primary amino acids in biological materials by high-performance liquid chromatography and photodiode array detection

Determination of free- and protein primary amino acids in biological materials by high-performance liquid chromatography and photodiode array detection

Improved method for the measurement of large neutral amino acids in biological matrices

A high-performance liquid chromatographic method for measuring neutral amino acids in rat sera, brain tissues, and perfusates was developed by using o-phthalaldehyde sulfite as a pre-column derivatization reagent. With the present method, it was possible to separate the neutral amino acids within a single run in 25 min, while the acidic amino acids were eluted near or at the solvent front. The recovery was above 88.8% with a relative standard deviation (RSD) below 4.2%. The within- and between-day assay reproducibility for the determination of rat serum amino acids showed RSDs below 1.35 and 7.61%, respectively. In the present study, the neutral amino acids were assayed with high sensitivity, accuracy and good reproducibility in a relatively short time and on a small sample size.

Separation of double conjugates of bile acids by two-dimensional high-performance thin-layer chromatography with tetra-n-butylammonium phosphate and methyl β-cyclodextrin

This paper describes a method for the separation, by high-performance thin-layer chromatography (HPTLC), of a series of polar, ionic, and hydrophilic double conjugates of bile acids amidated at the C-24 carboxyl group with glycine or taurine and sulfonated or glucosylated at hydroxyl groups in the 5β-steroid nucleus. The method involves two-dimensional (2D) reversed-phase (RP) HPTLC with the combined use of tetra-n-butylammonium phosphate (TBAP) and methyl β-cyclodextrin (Me-β-CD) as mobile phase additives. Complete separation of the hydrophilic bile acid conjugates, particularly of the recalcitrant pairs of chenodeoxycholic acid and deoxycholic acid conjugates in each group, was achieved by 2D inclusion RPHPTLC by developing with methanol-water-0.5 mol L−1 TBAP, 90:10:5–75:25:5 (ν/ν) in the first dimension and the same mobile phase containing 5mm Me-β-CD in the second dimension. The method could be usefully applied to biosynthetic and metabolic studies of bile acids in biological materials.