High-pressure Liquid Chromatography-mass Spectrometry Research Articles

Secondary bile acids in portal blood contribute to liver regeneration in a rat model of partial hepatectomy.

Gut metabolites via the portal vein affect several liver functions, including regeneration. Here, we investigated gut microbiota-derived metabolites in portal and peripheral serum during liver regeneration. We developed rat models of 70% partial hepatectomy (PHx) with and without prior gut microbiota modulation by three-week antibiotic (Abx) treatment. Sham without Abx were used as controls and compared to sham with Abx. Liver regeneration at day 2 following PHx was assessed by expression of proliferating cell nuclear antigen (PCNA) protein in liver tissues and cyclin genes in primary hepatocytes. High pressure liquid chromatography-mass spectrometry (HPLC-MS) based portal and peripheral venous serum metabolomics was performed to identify differentially altered metabolites (DAMs). Compared to controls, rat livers at day 2 post-PHx showed significant upregulation in the average number of PCNA-positive cells, which positively correlated with the expression of cell cycle genes in hepatocytes. In Abx-treated PHx, we observed reduced PCNA-positivity and downregulation in gene expression of various cyclins in hepatocytes compared to PHx. We identified 224 DAMs between controls vs PHx and 189 DAMs between Abx-treated PHx vs PHx in portal serum. Many common DAMs showed opposite expression trends in PHx vs controls and then Abx+PHx vs PHx in portal serum, such as sphingosine-1-phosphate and deoxycholic acid. In vitro studies with deoxycholic acid demonstrated that it enhanced the viability and proliferation of primary hepatocytes and hepatocyte organoids. The study underscores the critical role of deoxycholic acid in portal blood in enhancing hepatocyte proliferation and subsequently, liver regeneration.

Oligoester Identification in the Inner Coatings of Metallic Cans by High-Pressure Liquid Chromatography-Mass Spectrometry with Cone Voltage-Induced Fragmentation.

The application of polyesters as food contact materials is an alternative to epoxy resin coatings, which can be a source of endocrine migrants. By using high-pressure liquid chromatography/electrospray ionization-mass spectrometry (HPLC/ESI-MS) with cone voltage-induced fragmentation in-source, a number of polyester-derived migrants were detected in the extracts of inner coatings of metallic cans. The polyester-derived migrants were detected in each inner coating of fish product-containing cans (5/5) and in one inner coating of meat product-containing can (1/5). They were not detected in the inner coatings of vegetable/fruit product-containing cans (10 samples). The respective detected parent and product ions enabled differentiation between cyclic and linear compounds, as well as unambiguous identification of diol and diacid units. Most of the detected compounds, cyclic and linear, were composed of neopentyl glycol as diol and two diacid comonomers, namely isophthalic acid and hexahydrophthalic acid. The other detected oligoesters were composed of neopentyl glycol or propylene glycol and adipic acid/isophthalic acid as comonomers. The compounds containing propylene glycol as diol were found to be exclusively linear cooligoesters. On the basis of abundances of [M+Na]+ ions, the relative contents of cyclic and linear oligoesters were evaluated.

(E)-2-Benzylidenecyclanones: Part XVIII Study the Possible Link between Glutathione Reactivity and Cancer Cell Cytotoxic Effects of Some Cyclic Chalcone Analogs A Comparison of the Reactivity of the Open-Chain and the Seven-Membered Homologs.

Non-enzymatic thiol addition into the α,β-unsaturated carbonyl system is associated with several biological effects. In vivo, the reactions can form small-molecule thiol (e.g., glutathione) or protein thiol adducts. The reaction of two synthetic (4'-methyl- and 4'-methoxy substituted) cyclic chalcone analogs with reduced glutathione (GSH) and N-acetylcysteine (NAC) was studied by (high-pressure liquid chromatography-ultraviolet spectroscopy) HPLC-UV method. The selected compounds displayed in vitro cancer cell cytotoxicity (IC50) of different orders of magnitude. The structure of the formed adducts was confirmed by (high-pressure liquid chromatography-mass spectrometry) HPLC-MS. The incubations were performed under three different pH conditions (pH 3.2/3.7, 6.3/6.8, and 8.0/7.4). The chalcones intrinsically reacted with both thiols under all incubation conditions. The initial rates and compositions of the final mixtures depended on the substitution and the pH. The frontier molecular orbitals and the Fukui function were carried out to investigate the effects on open-chain and seven-membered cyclic analogs. Furthermore, machine learning protocols were used to provide more insights into physicochemical properties and to support the different thiol-reactivity. HPLC analysis indicated diastereoselectivity of the reactions. The observed reactivities do not directly relate to the different in vitro cancer cell cytotoxicity of the compounds.

Comprehensive analysis of alkenones by reversed-phase HPLC-MS with unprecedented selectivity, linearity and sensitivity

Alkenones are among the most widely used paleotemperature biomarkers. Traditionally, alkenones are analyzed using gas chromatography-flame ionization detector (GC-FID), or GC-chemical ionization-mass spectrometry (GC-CI-MS). However, these methods encounter considerable challenges for samples that exhibit matrix interference or low concentrations, with GC-FID requiring tedious sample preparations and GC-CI-MS suffering from nonlinear response and a narrow linear dynamic range. Here we demonstrate that reversed-phase high pressure liquid chromatography-mass spectrometry (HPLC-MS) methods provide excellent resolution, selectivity, linearity and sensitivity for alkenones in complex matrices. We systematically compared the advantages and limitations of three mass detectors (quadrupole, Orbitrap, and quadrupole-time of flight) and two ionization modes (electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI)) for alkenone analyses. We demonstrate that ESI performs better than APCI as response factors of various unsaturated alkenones are similar. Among the three mass analyzers tested, orbitrap MS provided the lowest limit of detection (0.4, 3.8 and 8.6 pg injected masses for Orbitrap, qTOF and single quadrupole MS, respectively) and the widest linear dynamic range (600, 20 and 30 folds for Orbitrap, qTOF and single quadrupole MS, respectively). Single quadrupole MS operated in ESI mode provides accurate quantification of proxy measurements over a wide range of injection masses, and with its modest instrument cost, represents an ideal method for routine applications. Analysis of global core-top sediment samples confirmed the efficacy of HPLC-MS methods for the detection and quantification of paleotemperature proxies based on alkenones and their superiority over GC-based methods. The analytical method demonstrated in this study should also allow highly sensitive analyses of diverse aliphatic ketones in complex matrices.

Creatine Deficiency Syndromes: Comparison of Screening Methods and Characterization of Four Novel Intronic Variants

BackgroundCerebral creatine deficiency syndromes (CCDS) are disorders affecting creatine synthesis or transport. Several methods have been developed to measure creatine and guanidinoacetate (GAA) in different body fluids including methods based on gas chromatography-mass spectrometry (GC–MS) and High-pressure liquid chromatography mass spectrometry (HPLC-MS). The diagnosis of CCDS is then confirmed by sequencing of creatine biosynthesis genes guanidinoacetate methyltransferase (GAMT) and Arginine: glycine amidinotransferase (GATM) and creatine transporter gene solute carrier family 6 member 8 (SLC6A8) or by functional enzymatic assay. The aim of the current study was to find the most reliable and accurate screening method for CCDS by comparing methods using Nuclear Magnetic Resonance spectroscopy (NMR), GC–MS and HPLC-MS. Additionally, this study was performed to estimate the prevalence of CCDS in a cohort of Egyptian patients and potentially to discover novel variants. Subjects and methodsThe study was conducted on 150 subjects with clinical signs and symptoms consistent with CCDS. Metabolic profiling of urine samples was performed using three techniques: 1) GC–MS 2) Ultra high-pressure (or performance) liquid chromatography – Tandem Mass Spectrometry (UHPLC- MS/MS) and 3) NMR. ResultsThe linearity of peak areas for creatine and GAA by UHPLC-MS/MS and NMR covered and exceeded the ranges normally found in urine. The limit of quantification and the inter-day precision results for creatine and GAA were more robust by UHPLC-MS/MS than NMR. Ten cases were identified as being positive for CCDS by our analytical approaches and underwent next generation sequencing (NGS) for GAMT, GATM and SLC6A8 genes. NGS was performed and confirmed one patient with one likely Pathogenic variant in GAMT gene: (NC_000019.10:g.1401317C > G, NP_000147.1:p.Ala54Pro). Additionally, we describe four novel intronic variants in the GATM gene: c.1043-357del and c.1043-357_1043-356insT, and were predicted to activate cryptic acceptor site with potential alteration of splicing, c.979-227G > A was found to significantly alter the Exon Splice Enhancer (ESE) xon Splice Silencer (ESS) motifs ratio and c.1042 + 262del which was found to have no implications on splicing. ConclusionsBoth UHPLC-MS/MS and NMR spectroscopy are comparable to GC–MS in screening for CCDS. Nonetheless, the UHPLC-MS/MS method had better performance than NMR spectroscopy. Additionally, Sequencing of the full length of GATM, GAMT, and SLC6A8 genes is needed to identify intronic variants that could cause CCDS via affecting splice sites.

Novel n-MoSSe/p-Co3O4 Z-scheme heterojunction photocatalyst for highly boosting photoelectrochemical and photocatalytic activity

The development of stable, efficient photocatalyst for environmental antibiotics degradation is great significant and remains a major challenge. Herein, novel 2D/0D n-MoSSe/p-Co3O4 Z-scheme heterojunction catalysts (MSCO) are developed to combine the advantages of n-type MoSSe nanoplates and p-type Co3O4 nanoparticles. With an optimized Co3O4 loading ratio, the MSCO2 sample exhibited 7.8 and 28.8 times of photocurrent density more than that of pure MoSSe and Co3O4, and likewise showed 2.54 and 8.91 times of photocatalytic tetracycline hydrochloride removal rate more than that of pure MoSSe and Co3O4. Moreover, the heterojunction displayed outstanding recyclability after five cycles. The remarkably enhanced catalytic properties were mainly ascribed to the 2D/0D structure, built-in electric field between p-n heterojunction and electron transfer the Z-Scheme pathways which was helpful to promote the separation of photogenerated carriers. Additionally, the corresponding reaction pathway and photocatalytic mechanism were further elucidated by the results of the electron spin resonance (ESR) and high-pressure liquid chromatography-mass spectrometry (HPLC-MS). This research provided a new idea for the construction of Z-Scheme p-n heterojunction with 2D/0D structure in photocatalysis, photoelectrochemistry, and electrocatalysis.

Community overdose surveillance: Comparing substances collected from the death scene investigation to toxicology results

BackgroundRecent overdose trends are characterized by increased toxicological detection of stimulants with opioids, yet it is unclear whether these substances are mixed prior to consumption or purposefully used simultaneously. MethodsPostmortem toxicology data were collected in Marion County, Indiana, from 45 fatal overdose cases involving heroin, fentanyl, methamphetamine, or cocaine. Substances found by death scene investigators at the scene of the fatal overdose (57 samples) were tested using high-pressure liquid chromatography mass-spectrometry (LC–MS) technology. We compared toxicology and LC–MS results to understand whether substances contributing to overdose were found in combination or separately at the scene of the overdose. ResultsComparing toxicology reports with LC–MS results from substances found at the scene of overdose deaths involving opioids and stimulants reveal that deaths are largely the result of the co-use of opioids and stimulants, rather than use of stimulants combined with opioids. ConclusionsCollecting and testing physical samples from fatal overdose scenes and comparing these to post-mortem toxicology results is a new way to examine polydrug use patterns. This community overdose surveillance method can be used to improve overdose prevention and response efforts.

Meibum lipid composition in type 2 diabetics with dry eye

PurposeThe purpose of this investigation was to analyze and compare the composition of meibum between type 2 diabetics with dry eye disease (DED) and control subjects to better reveal the pathologic mechanisms of the meibomian gland degeneration (MGD) and DED in type 2 diabetes mellitus (T2DM). Methods90 subjects were divided into the following 4 groups: DM-DED group: T2DM patients with DED (n = 30); DM control group: DM patients without DED (n = 18); DED group: DED patients without DM (n = 26); naive control group: normal subjects (n = 16). The lipid composition of meibum samples collected from these subjects was analyzed by high-pressure liquid chromatography–mass spectrometry (HPLC-MS) system. The content of lipid features from 12 major lipid classes was compared among the 4 groups. ResultsA significantly lower level of triacylglycerols (TG) and wax esters (WE) was found between DM-DED patients and normal controls (P < 0.01), whereas the level of Cholesteryl Ester (CE) in DM-DED patients increased compared with DED patients (P < 0.05). The level of (O-acyl)-omega-hydroxy fatty acids (OAHFA) in DM-DED patients was significantly lower than that in normal controls (P < 0.01). An opposite higher level of phospholipids (PLs) was observed in DM-DED patients than that in normal controls (P < 0.01). ConclusionsT2DM could influence the expression of meibum lipids to further aggravate DED and MGD. Lower expression of TG,WE and OAHFA, higher expression of CE and PLs were discovered in meibum lipids of T2DM-DED.

Characterization of non-ionic surfactants in Winsor &amp; Newton's water-mixable oil paints

Abstract Water-mixable oil (WMO) paints are a relatively new addition to the artists’ palette that have increased in usage and popularity over the past few decades. Understanding the composition and properties of WMO paint is essential for the artists who use them and for the people who work with WMO paintings—particularly art conservators. However, the formulations that make WMO paints possible remain undisclosed by paint manufacturers. In this research, fresh paint and naturally-aged paint-outs from Winsor & Newton’s Artisan WMO products were used to study the chemistry of WMO paints. The development of a unique high-pressure liquid chromatography mass spectrometry (HPLC-MS) method enabled the separation and detection of the non-ionic surfactants in the Artisan WMO paints. A data visualization strategy using contour plots was applied for interpretation of results, affording, for the first time, complete structural identifications of surfactant molecules in a WMO paint. The paints were found to contain a complex mixture of ethoxylated molecules, including polyoxyethylene (POE) fatty acid esters derived from the fatty acid mixture of linseed oil. An exudate that formed from the cured paints was also analyzed. More-saturated fatty acid esters, POE oleate and POE stearate, were detected; however, more-reactive POE fatty acid esters were found absent, providing insight relating to the stability of surfactants in the Artisan WMO paints as well as potential curing reactions. HPLC-MS studies were contextualized with physical observations and surface measurements that were performed on the cured samples. Tacky surfaces observed on the cured paint films showed significantly higher surface gloss and surface hydrophilicity; these observations were quantified using glossimetry and droplet contact angle measurements. These results provide insight into the unique chemistry present in WMO paints and provide a basis for future studies for art conservators and conservation scientists working with this new media.

Differentiation of bisphenol F diglycidyl ether isomers and their derivatives by HPLC-MS and GC-MS\u2014comment on the published data

Positional isomers of bisphenol F diglycidyl ether (BFDGE) have been analyzed by high-pressure liquid chromatography-mass spectrometry and by gas chromatography-mass spectrometry (HPLC-MS, GC-MS). Positional isomers of BFDGE derivatives (BFDGEx2H2O, BFDGExH2OxHCl) have been analyzed by HPLC-MS. On the basis of the obtained fragmentation patterns, the elution order of the isomers has been unequivocally determined, in standard solutions and in the sample of liquid obtained after rinsing an empty mackerel fish can with acetonitrile. Under HPLC condition, para,para isomers are eluted first, then ortho,para isomers’ elution follows, and ortho,ortho isomers are eluted last. Under GC condition, the reverse elution order has been obtained. For the first time, two ortho,para isomers of BFDGExH2OxHCl have been detected and their elution order has been determined. The obtained results are of key importance for determination of the isomer distribution of BFDGE and its derivatives in food samples.

Visual System Impairment in a Mouse Model of Krabbe Disease: The Twitcher Mouse.

Krabbe disease (KD, or globoid cell leukodystrophy; OMIM #245200) is an inherited neurodegenerative condition belonging to the class of the lysosomal storage disorders. It is caused by genetic alterations in the gene encoding for the enzyme galactosylceramidase, which is responsible for cleaving the glycosydic linkage of galatosylsphingosine (psychosine or PSY), a highly cytotoxic molecule. Here, we describe morphological and functional alterations in the visual system of the Twitcher (TWI) mouse, the most used animal model of Krabbe disease. We report in vivo electrophysiological recordings showing defective basic functional properties of the TWI primary visual cortex. In particular, we demonstrate a reduced visual acuity and contrast sensitivity, and a delayed visual response. Specific neuropathological alterations are present in the TWI visual cortex, with reduced myelination, increased astrogliosis and microglia activation, and around the whole brain. Finally, we quantify PSY content in the brain and optic nerves by high-pressure liquid chromatography-mass spectrometry methods. An increasing PSY accumulation with time, the characteristic hallmark of KD, is found in both districts. These results represent the first complete characterization of the TWI visual system. Our data set a baseline for an easy testing of potential therapies for this district, which is also dramatically affected in KD patients.

Dark Iron-Catalyzed Reactions in Acidic and Viscous Aerosol Systems Efficiently Form Secondary Brown Carbon.

Iron-driven secondary brown carbon formation reactions from water-soluble organics in cloud droplets and aerosols create insoluble and soluble products of emerging atmospheric importance. This work shows, for the first time, results on dark iron-catalyzed polymerization of catechol forming insoluble black polycatechol particles and colored water-soluble oligomers under conditions characteristic of viscous multicomponent aerosol systems with relatively high ionic strength (I = 1-12 m) and acidic pH (∼2). These systems contain ammonium sulfate (AS)/nitrate (AN) and C3-C5 dicarboxylic acids, namely, malonic, malic, succinic, and glutaric acids. Using dynamic light scattering (DLS) and ultra high pressure liquid chromatography-mass spectrometry (UHPLC-MS), we show results on the rate of particle growth/agglomeration and identity of soluble oligomeric reaction products. We found that increasing I above 1 m and adding diacids with oxygen-to-carbon molar ratio (O:C > 1) significantly reduced the rate of polycatechol formation/aggregation by a factor of 1.3 ± 0.4 in AS solution in the first 60 min of reaction time. Using AN, rates were too slow to be quantified using DLS, but particles formed after 24 h reaction time. These results were explained by the relative concentration and affinity of ligands to Fe(III). We also report detectable amounts of soluble and colored oligomers in reactions with a slow rate of polycatechol formation, including organonitrogen compounds. These results highlight that brown carbon formation from iron chemistry is efficient under a wide range of aerosol physical states and chemical composition.

Structures of new C41 carotenoids produced using recombinant Escherichia coli expressing genes encoding isopentenyl pyrophosphate, methyltransferase, and carotenoid biosynthetic enzymes

The production of methylated C41-C43 15-cis-phytoene, lycopene, β-carotene, and zeaxanthin using recombinant Escherichia coli that express the genes encoding isopentenyl pyrophosphate, C4-methyltransferase, and carotenoid biosynthetic enzymes, as well as the detection of their chemical structures using high-pressure liquid chromatography-mass spectroscopy (HPLC-MS) analyses have been previously reported. However, the positions of the methyl groups were not fully elucidated due to multiple possible sites that could be methylated. In this study, we have isolated the methylated carotenoids using chromatographic methods and unambiguously determined their structures as 16-methyl derivatives of 15-cis-phytoene, lycopene, β-carotene, and zeaxanthin via detailed MS, 1D, and 2D NMR analyses. These compounds were all identified as novel C41 carotenoids.

Pepper Bacterial Spot Control by Bacillus velezensis: Bioprocess Solution

Pepper bacterial spot is one of the most severe plant diseases in terms of infection persistence and economic losses when it comes to fresh pepper fruits used in nutrition and industrial processing. In this study, Bacillus velezensis IP22 isolated from fresh cheese was used as a biocontrol agent of pepper bacterial spot, whose main causal agent is the cosmopolitan pathogen Xanthomonas euvesicatoria. After optimization of the cultivation medium composition aimed at maximizing of the antimicrobial activity against X. euvesicatoria and validation of the optimized medium at the scale of a laboratory bioreactor, in planta tests were performed. The results have showed significant suppression of bacterial spot symptoms in pepper plants by the produced biocontrol agent, as well as reduction of disease spreading on the healthy (uninoculated) pepper leaves. Furthermore, HPLC-MS (high pressure liquid chromatography–mass spectrometry) analysis was employed to examine antimicrobial metabolites produced by B. velezensis IP22, where lipopeptides were found with similar m/z values compared to lipopeptides from fengycin and locillomycin families. The bioprocess solution developed at the laboratory scale investigated in this study represents a promising strategy for production of pepper bacterial spot biocontrol agent based on B. velezensis IP22, a food isolate with a great perspective for application in plant protection.

Investigating the Ionization of Dissolved Organic Matter by Electrospray.

Electrospray ionization (ESI) operating in the negative mode coupled to high-resolution mass spectrometry is the most popular technique for the characterization of dissolved organic matter (DOM). The vast molecular heterogeneity and the functional group diversity of this complex mixture prevents the efficient ionization of the organic material by a single ionization source, so the presence of uncharacterized material is unavoidable. The extent of this poorly ionizable pool of carbon is unknown, is presumably variable between samples, and can only be assessed by the combination of analysis with a uniform detection method. Charged aerosol detection (CAD), whose response is proportional to the amount of nonvolatile material and is independent from the physicochemical properties of the analytes, is a suitable candidate. In this study, a fulvic acid mixture was fractionated and analyzed by high-pressure liquid chromatography–mass spectrometry in order to investigate the polarity and size distributions of highly and poorly ionizable material in the sample. Additionally, DOM samples of terrestrial and marine origins were analyzed to evaluate the variability of these pools across the land–sea aquatic continuum. The relative response factor values indicated that highly ionizable components of aquatic DOM mixtures are more hydrophilic and have lower molecular weight than poorly ionizable components. Additionally, a discrepancy between the samples of terrestrial and marine origins was found, indicating that marine samples are better represented by ESI than terrestrial samples, which have an abundant portion of hydrophobic poorly ionizable material.

Lipid Profiling in Epicardial and Subcutaneous Adipose Tissue of Patients with Coronary Artery Disease.

Coronary artery disease is one of the most frequent causes of morbidity and mortality worldwide. It is even more prevalent in patients with type 2 diabetes mellitus who suffer from obesity and increased accumulation of epicardial fat with a possible contributing role in the development of coronary artery disease. We performed an MS-based lipidomic analysis of subcutaneous and epicardial adipose tissue in 23 patients with coronary artery disease stratified for the presence/absence of type 2 diabetes mellitus and a control group of 13 subjects aiming at identification of factors from epicardial fat contributing to the development of coronary artery disease. The samples of adipose tissues were obtained during elective cardiac surgery. They were extracted and analyzed with and without previous triacylglycerols separation by high-pressure liquid chromatography-mass spectrometry (HPLC-MS). Multivariate and univariate analyses were performed. Lipidomics data were correlated with biochemical parameters. We identified multiple changes in monoacylglycerols, diacylglycerols, triacylglycerols, glycerophosphatidylserines, glycerophosphatidylethanolamines, glycerophosphatidylcholines, ceramides, sphingomyelins, and derivatives of cholesterol. Observed changes included molecules with fatty acids with odd (15:0, 15:1, 17:0, 17:1) and even (10:0, 12:0, 14:0, 16:0, 16:1, 18:0, 18:1, 18:2, 20:4, 20:1, 22:0) fatty acids in both types of adipose tissue. More pronounced changes were detected in epicardial adipose tissue compared to subcutaneous adipose tissue of patients with coronary artery disease and type 2 diabetes. Lipidomic analysis of subcutaneous and epicardial adipose tissue revealed different profiles for patients with coronary artery disease and type 2 diabetes, which might be related to coronary artery disease and the presence of type 2 diabetes.

Fermented Wild Ginseng by Rhizopus oligosporus Improved l-Carnitine and Ginsenoside Contents.

We conducted this study to investigate the beneficial effects of Rhizopus oligosporus fermentation of wild ginseng on ginsenosides, l-carnitine contents and its biological activity. The Rhizopus oligosporus fermentation of wild ginseng was carried out at 30 °C for between 1 and 14 days. Fourteen ginsenosides and l-carnitine were analyzed in the fermented wild ginseng by the ultra high pressure liquid chromatography–mass spectrometry (UPLC–MS) system. Our results showed that the total amount of ginsenosides in ginseng increased from 3274 to 5573 mg/kg after 14 days of fermentation. Among the 14 ginsenosides tested, the amounts of 13 ginsenosides (Rg1, Rb2, Rb3, Rc, Rd, Re, Rf, Rg2, Rg3, Rh1, compound K, F1 and F2) increased, whereas ginsenoside Rb1 decreased, during the fermentation. Furthermore, l-carnitine (630 mg/kg) was newly synthesized in fermented ginseng extract after 14 days. In addition, both total phenol contents and DPPH radical scavenging activities showed an increase in the fermented ginseng with respect to non-fermented ginseng. These results show that the fermentation process reduced the cytotoxicity of wild ginseng against RAW264.7 cells. Both wild and fermented wild ginseng showed anti-inflammatory activity via inhibition of nitric oxide synthesis in RAW264.7 murine macrophage cells.

Population Pharmacokinetics of Teicoplanin in Preterm and Term Neonates: Is It Time for a New Dosing Regimen?

Our objective was to develop a population pharmacokinetic (PK) model in order to evaluate the currently recommended dosing regimen in term and preterm neonates. By using an optimal design approach, a prospective PK study was designed and implemented in 60 neonates with postmenstrual ages (PMA) of 26 to 43 weeks. A loading dose of 16 mg/kg was administered at day 1, followed by a maintenance dose of 8 mg/kg daily. Plasma concentrations were quantified by high-pressure liquid chromatography-mass spectrometry. Population PK (popPK) analysis was performed using NONMEM software. Monte-Carlo (MC) simulations were performed to evaluate currently recommended dosing based on a pharmacodynamic index of area under the concentration-time curve (AUC)/MIC ratio of ≥400. A two-compartment model with linear elimination best described the data by the following equations: clearance (CL) = 0.0227 × (weight [wt]/1,765)0.75 × (estimated creatinine clearance [eCRCL]/22)0.672, central compartment volume of distribution (V1) = 0.283 (wt/1,765), intercompartmental clearance (Q) = 0.151 (wt/1,765)0.75, and peripheral compartment volume (V2) = 0.541 (wt/1,765). The interindividual variability estimates for CL, V1, and V2 were 36.5%, 45.7%, and 51.4%, respectively. Current weight (wt) and estimated creatinine clearance (eCRCL) significantly explained the observed variability. MC simulation demonstrated that, with the current dosing regimen, an AUC/MIC ratio of ≥400 was reached by only 68.5% of neonates with wt of <1 kg when the MIC was equal to 1 mg/kg, versus 82.2%, 89.7%, and 92.7% of neonates with wt of 1 to <2, 2 to <3, or ≥3 kg, respectively. Augmentation of a maintenance dose up to 10 or 11 mg/kg for preterm neonates with wt of 1 to <2 or <1 kg, respectively, increases the probability of reaching the therapeutic target; the recommended doses seem to be adequate for neonates with wt of ≥2 kg. Teicoplanin PK are variable in neonates, with wt and eCRCL having the most significant impact. Neonates with wt of <2 kg need higher doses, especially for Staphylococcus spp. with an MIC value of ≥1 mg/liter.

Deoxyinosine and 7-Deaza-2-Deoxyguanosine as Carriers of Genetic Information in the DNA of Campylobacter Viruses.

Several reports have demonstrated that Campylobacter bacteriophage DNA is refractory to manipulation, suggesting that these phages encode modified DNA. The characterized Campylobacter jejuni phages fall into two phylogenetic groups within the Myoviridae: the genera Firehammervirus and Fletchervirus Analysis of genomic nucleosides from several of these phages by high-pressure liquid chromatography-mass spectrometry confirmed that 100% of the 2'-deoxyguanosine (dG) residues are replaced by modified bases. Fletcherviruses replace dG with 2'-deoxyinosine, while the firehammerviruses replace dG with 2'-deoxy-7-amido-7-deazaguanosine (dADG), noncanonical nucleotides previously described, but a 100% base substitution has never been observed to have been made in a virus. We analyzed the genome sequences of all available phages representing both groups to elucidate the biosynthetic pathway of these noncanonical bases. Putative ADG biosynthetic genes are encoded by the Firehammervirus phages and functionally complement mutants in the Escherichia coli queuosine pathway, of which ADG is an intermediate. To investigate the mechanism of DNA modification, we isolated nucleotide pools and identified dITP after phage infection, suggesting that this modification is made before nucleotides are incorporated into the phage genome. However, we were unable to observe any form of dADG phosphate, implying a novel mechanism of ADG incorporation into an existing DNA strand. Our results imply that Fletchervirus and Firehammervirus phages have evolved distinct mechanisms to express dG-free DNA.IMPORTANCE Bacteriophages are in a constant evolutionary struggle to overcome their microbial hosts' defenses and must adapt in unconventional ways to remain viable as infectious agents. One mode of adaptation is modifying the viral genome to contain noncanonical nucleotides. Genome modification in phages is becoming more commonly reported as analytical techniques improve, but guanosine modifications have been underreported. To date, two genomic guanosine modifications have been observed in phage genomes, and both are low in genomic abundance. The significance of our research is in the identification of two novel DNA modification systems in Campylobacter-infecting phages, which replace all guanosine bases in the genome in a genus-specific manner.

Lacto-fermented Kenaf (Hibiscus cannabinus L.) seed protein as a source of bioactive peptides and their applications as natural preservatives

Kenaf seeds are a promising source of natural preservatives for food applications due to their potential as a substrate to generate peptides with high antibacterial activity. We sought to generate bioactive peptides with antibacterial activity from Kenaf seed proteins via lacto-fermentation. The ground seeds were defatted and protein extracted using acid precipitation. Kenaf seed protein was fermented with Lactobacillus casei for 72 h at 37 °C, and the antibacterial activity, MIC, and MBC were determined using a 96-well microtiter plate assay. The fermented protein was subjected to fractionation and peptide identification using reversed-phase high pressure liquid chromatography and liquid chromatography-mass spectrometry, respectively. The fermented protein showed high antibacterial activity against Salmonella typhimurim, Escherichia coli, Psedomonas aerginosa, Staphylococcus aureus, Bacilus subtilis, and Streptococcus pyogenes. The MIC value was 4 mg/mL against all tested pathogens and the MBC value was 8 mg/mL against S. typhimurium, P. aureginosa, and E. coli and 4 mg/mL against B. subtilis, S. aureus, and S. pyogenes. Fraction 17 demonstrated the strongest antibacterial activity (98%–100%), and five peptides sequences were identified in this fraction. The findings of this study demonstrated high potential for kenaf seed protein fermented using Lactobacillus casei as a source of natural preservatives for a broad range of food applications.