Gas Chromatography-mass Spectrometry Research Articles

Molecular epidemiology of Burkholderia pseudomallei in Hainan Province of China based on O-antigen

BackgroundBurkholderia pseudomallei is a gram-negative bacterium widely found in Southeast Asia and northern Australia. This bacterium, which lacks an available vaccine, is the causative agent of melioidosis and has properties that potentially enable its exploitation as a bioweapon. MethodsPolymerase chain reaction assays targeting each of the lipopolysaccharide (LPS) genetic types were used to investigate genotype frequencies in B. pseudomallei populations. Silver staining, gas chromatography-mass spectrometry (GC-MS), and immunofluorescence were used to characterize LPS. ResultsIn our study, a total of 169 clinical B. pseudomallei isolates were collected from Hainan, China between 2004 and 2016. The results showed that LPS genotype A was the predominant type, comprising 91.1% of the samples, compared with only 8.9% of LPS genotype B. The majority of patients were male and were diagnosed with sepsis or pneumonia. Silver staining and GC-MS demonstrated that LPS genotypes A and B exhibited distinct phenotypes and molecular structures. Immunofluorescence tests showed there was no cross-reaction between LPS genotypes A and B. ConclusionThis is the first report on the molecular epidemiology of B. pseudomallei based on O-antigen in China. Tracking the regional distribution of different LPS genotypes offers significant insights relevant to the development and administration of LPS-based vaccines.

Metabolite Profiling of Annual Ryegrass Cultivars to Assess Disease Resistance and Susceptibility.

Direct immersion solid-phase microextraction coupled with gas chromatography-mass spectroscopy was used to create chemical fingerprints of annual ryegrass cultivars (Lolium rigidum). Extracts made of the inflorescences of four cultivars and one accession of annual ryegrass were assessed to identify differential metabolites between those resistant to and susceptible to bacterial galls associated with annual ryegrass toxicity (ARGT). Numerous compounds were identified. Principal component analysis showed distinct clustering of metabolites from disease-resistant and disease-susceptible cultivars. Partial least-squares-discriminant analysis identified sterols, esters, aldehydes, and terpenes that correlated with resistance to galls formation. Esters, sterols, phenols, heterocyclics, fatty acids, organofluorides, and siloxanes were predominant in resistant genotypes, whereas alcohols, aldehydes, terpenes, and hydrocarbons were predominant in susceptible genotypes. The identification of differentially expressed metabolites provides potential chemical markers to guide breeding strategies for ARGT resistance in ryegrass.

Phytochemical profiling, spectroscopic identification of active compounds, and mechanism of the anticandidal properties of Datura stramonium L. using SwissADMET prediction and molecular docking analysis

BackgroundDatura stramonium L., a wild-growing herb, has been traditionally used to treat various ailments, including toothache, asthma, rheumatism, epilepsy, and alopecia. Scientific evidence supports its anticancer, anti-inflammatory, anti-asthmatic, anticholinergic, antifungal, and antibacterial properties. AimThis study aimed to isolate, characterize, and identify the most potent anticandidal compounds inhibiting the growth of Candida spp., while also predicting their drug-likeness and toxicity profiles. MethodThe anticandidal activity of D. stramonium leaf extracts was assessed using the Agar well-diffusion method and minimum inhibitory concentration (MIC) was determined by the broth dilution method. The most active extract was selected for column chromatography. Different fractions were collected and screened against pathogenic Candida spp. The most active fraction was subjected to Gas chromatography-Mass spectrometry (GC-MS), Fourier Transform-Infrared Spectroscopy (FT-IR), and Nuclear Magnetic Resonance (NMR) analysis. Additionally, computational tools such as molecular docking and ADMET prediction provided further insights into the molecular interactions between the target enzymes. ResultsIn vitro anticandidal activity demonstrated that the ethyl acetate extract exhibited significant activity against human pathogenic Candida spp., with the highest zones of inhibition against Candida guilliermondii (20.33±0.56 mm), Candida tropicalis (16.33±0.58 mm), and Candida albicans (14.66±1.05 mm), with a minimum inhibitory concentration (MIC) value of 25 ug/ml. Additionally, the most potent fraction (F8) obtained from the Column revealed significant anticandidal activity. GC-MS analysis of the F8 fraction indicated the presence of 23 compounds, with the major compounds being Phthalic acid, di(2-propylpentyl) ester (Compound 1), Pentadecane (Compound 2), Octadecane (Compound 3), Benzoic acid, 3-Amino-5-Hydroxy-, Methyl ester (Compound 4), and 1,2-Benzenedicarboxylic acid, bis (2-ethylhexyl) ester (Compound 5). This study reports all 23 compounds from D. stramonium for the first time. Furthermore, NMR studies confirmed the presence of Phthalic acid, di(2-propylpentyl) ester as the most abundant compound, designated as compound 1. Finally, docking analysis revealed that compound 1 showed good binding affinities for the tested enzymes, with the highest binding scores of -7.084 Kcal/mol and -7.030 Kcal/mol with Lanosterol 14-alpha demethylase (PDB ID: 5JLC, 5TZ1). The results of the in silico pharmacokinetic and drug-likeness properties indicated that compound 1 is a potential anticandidal drug candidate. ConclusionThis study highlights that 23 compounds were reported from the leaf extract of D. stramonium for the first time. The findings suggest that compound 1 can be considered a new anticandidal drug candidate.

Rapid identification of fragrant rice using starch flavor compound via NIR spectroscopy coupled with GC–MS and Badh2 genotyping

The identification of fragrant rice varieties using near-infrared reflectance spectroscopy (NIRS) models has attracted extensive attention from regulatory authorities worldwide. In this study, 138 fragrant and 54 nonfragrant rice varieties were planted in the same region and distinguished using sensory evaluation, gas chromatography–mass spectrometry analysis, and betaine aldehyde dehydrogenase 2 (Badh2) genotyping. Then, the 2-acetyl−1-pyrroline (2-AP) content was assessed based on partial least-squares discriminant (PLS-DA) models generated after 2nd individually or combined with SNV/MSC/smoothing preprocessing successfully classified fragrant rice both in the calibration and predictive sets. Moreover, design of experiments (DoE)-based preprocessing selection was employed as an effective strategy to optimize the calibration models compared with the one variable at a time (OVAT) method. Further, Badh2 genotype sample screening assisted with identifying authentic fragrant rice and guaranteed the NIRS model's prediction accuracy in identifying fragrant rice. In conclusion, the high throughput PLS-DA multivariate method coupled with NIRS data was applied to identify fragrant rice varieties in routine monitoring and was effective, accurate, and rapid.

Textured vegetable protein from flaxseed press cake and pea – syntonizing chemical and structural properties

Flaxseed press cake (FS) was mixed with pea protein isolate and low-moisture twin-screw-extruded to valorize the oil production side stream as meat analogue. Water input, FS content, barrel temperature, and throughput were varied in a Box-Behnken design to test these factors’ influences on extrusion response parameters (pressure, temperature, mechanical energy input), lipid oxidation product and process contaminant formation (by liquid chromatography and head-space gas chromatography mass spectrometry), and mechanical properties of the TVPs.The water input was identified as the strongest influencing factor, reducing shear forces in the extruder and thereby reducing mechanical energy input, pressure, and temperature and affecting several TVP properties. Volatile lipid oxidation products from enzymatic oxidation in the raw materials are decomposed and steam-stripped during extrusion. Higher melt temperatures and lower water contents enhance this effect and promote the formation of masking “roasted” flavour compounds. However, acrylamide (<100 µg/kg) and trans-fatty acids (<0.4 g/kg) are also formed under flavour-improving conditions and TVP hardness is reduced. FS increases TVP density and reduces expansion and hardness. Reconciling mitigation of undesired chemical compounds and meat-like mechanical properties (at 16-18% water, 55-65% FS, mass flows <8 kg/h), a FS-based TVP can be created, combining nutritional and sustainability benefits of FS.

The effects of sample preparation on the interpretation of pyrolysis-based organic matter analysis in immature oil shale

Oil shale as well as shale oil and shale gas are significant energy resources with huge reserves present in different parts of the world. Various geochemical proxies have been applied to assess the petroleum potential of oil shales with samples pre-treated in various ways, e.g. as whole rock or demineralized sample or as solvent extracted rock/kerogen. In this respect, it is important to understand and quantify, how achieved geochemical parameters are influenced by pre-treatment. In this study, a systematic comparison is presented based on a study on i) whole rock, ii) extracted whole rock, iii) kerogen concentrate, and iv) extracted kerogen concentrate obtained after solvent extraction of demineralized shales. In total, seven immature, organic matter-rich samples from the Miocene lacustrine sediments of the Nördlinger Ries impact crater, Germany, were pretreated in this way leading to overall 28 samples. A set of elemental analysis (C, H, N), Rock-Eval pyrolysis, and Curie Point-pyrolysis–gas chromatography–mass spectrometry measurements were performed on these pretreated samples. Mineral matter removal leads to significant increase of total organic carbon, but also thermally evaporable and pyrolytically cracked organic matter (Rock-Eval S1 and S2 peaks). To some extent, labile organic matter represented in the original S2 peak can be destructed by mineral removal with hydrochloric and hydrofluoric acid, as shown by elevated values of PI [S1/(S1 + S2)] after demineralization. The organic matter type tends to be more petroleum-prone with raised hydrogen index (HI) and aliphaticity values after demineralization, while Rock-Eval Tmax values commonly applied as parameters for thermal maturity tend to decrease, though not for all samples.Reduced TOC, S1, S2 and PI values of extracted samples suggest that both thermally evaporable and additionally some non-evaporable but soluble organic matter hidden in the original S2 peak can be lost after solvent extraction. Increased values of HI, H/C and N/C of extracted samples indicate more oil-prone organic matter types than unextracted samples. Typical maturity-related parameters such as aliphaticity and Rock-Eval Tmax decrease. Smectite and zeolites, which are abundant in the samples, are suggested to protect organic matter to some extent against solvent extraction, influencing a variety of geochemical proxies and the occurrence of metal cation-containing minerals. Zeolite invigorates the protection effect.

Coprecipitation of nicotinic acid in PVP by gas antisolvent technique using Box-Behnken design

Nicotinic acid is a water-soluble compound recognized in the medical field for its ability to decrease low-density lipoprotein cholesterol levels. Additionally, nicotinic acid is used to alleviate the effects of heat stress in ruminant animals. The supercritical gas antisolvent technique was employed using carbon dioxide to encapsulate nicotinic acid in polyvinylpyrrolidone (PVP) using ethanol + acetone. Encapsulation efficiency, process yield and crystallite size data were evaluated using the Box-Behnken design. Gas chromatography-mass spectrometry quantified the encapsulation efficiency at (13.1 to 66.9)%, and the same technique was used to determine that the encapsulation of nicotinic acid increased the dissolution rate compared to the pure compound. A residual solvent level was quantified at least 33 times lower than the maximum permitted level. The encapsulation was shown to protect the active ingredient in thermal degradation tests in a climatic chamber. XRPD showed the stability of the crystalline structure of niacin after encapsulation, and the effects on its microstructure were evaluated using Rietveld analysis. Spectroscopic analysis showed evidence of intermolecular bonding between nicotinic acid particles and PVP. An average particle size of (80.4 to 238.9) µm was obtained by SEM analysis.

GC-MS uncovers unique metabolic markers of drug-resistant epilepsy in capillary but not venous dried blood spots

This study compared the effectiveness of capillary dried blood spots (DBS) versus venous DBS in detecting metabolic changes related to drug-resistant epilepsy (DRE). DBS samples were collected from 142 epilepsy patients (58 drug-resistant, 84 drug-responsive) via venipuncture or fingerstick capillary sampling. Metabolomic analysis using gas chromatography-mass spectrometry compared DBS metabolite profiles between the two groups. While venous DBS profiles showed no distinct patterns, capillary DBS profiles revealed clustering patterns in principal components analysis, with the first two principal components explaining 14.5%, and 13.5% of the total variance, respectively. Orthogonal PLS-DA confirmed group discrimination (R2Y=0.989, Q2=0.742). Drug-resistant patients exhibited elevated capillary DBS levels of glutamine, pyruvic acid, and serine, and decreased palmitic acid compared to drug-responsive patients. Pathway analysis revealed disruptions in amino acid metabolism, neurotransmission, and cellular energy regulation. Elevated glutamine levels may contribute to an imbalance between excitatory glutamate and inhibitory GABA neurotransmission, key factors in epileptogenesis and drug resistance. Capillary DBS, likely enriched with arterial blood supply to the brain, appears to better capture central nervous system metabolic disturbances compared to venous DBS containing systemic contributions. This minimally invasive capillary DBS approach offers effective metabolic profiling of brain conditions like DRE, for monitoring disease progression and treatment response, enhancing personalized patient management in epilepsy.

Ready-to-use Models Built Using a Diverse Set of 266 Aroma Compounds for the Estimation of Gas Chromatographic Retention Indices for the 50%-Cyanopropylphenyl-50%-Dimethylpolysiloxane Stationary Phase.

Retention index prediction based on the molecule structure is not often used in practice due to low accuracy, the need to use paid software to calculate molecular descriptors (MD), and the narrow applicability domain of many models. In recent years, relatively accurate and versatile deep learning (DL)-based models have emerged. These models are now used in practice as an additional criterion in gas chromatography-mass spectrometry identification. The DB-225ms stationary phase (usually described as 50%-cyanopropylphenyl-50%-dimethylpolysiloxane in available sources) is widely used, but ready-to-use retention index estimation models are not available for it. This study presents such models. The models are linear and use simple constitutional MD and retention indices predicted by DL for the DB-WAX and DB-624 stationary phases as MD (we show that it is their use that allows us to achieve satisfactory accuracy). The accuracy obtained for a completely unseen hold-out test set: root mean square error 73.2; mean absolute error 45.7; median absolute error 22.0. The models were trained using a retention data set of 266 volatile compounds. All calculations can be performed using the convenient open-source software CHERESHNYA. The final equations are implemented as a spreadsheet and a code snippet and are available online: https://doi.org/10.6084/m9.figshare.26800789.

Study on pyrolysis process and mechanism of organic coating of waste polyesterimide enameled wire based on density functional theory

The pyrolysis treatment of waste polyesterimide enameled wire offers significant advantages such as continuous processing, non-hazardous nature, and high resource recovery rate. However, research on its pyrolysis process and mechanism remains insufficiently explored. In this study, techniques including thermogravimetry (TG), Fourier transform infrared spectroscopy(FT-IR), pyrolysis–gas chromatography-mass spectrometry(Py-GC/MS) were employed to investigate pyrolysis temperature, weight loss rate, pyrolysis and kinetic parameters, composition and distribution of pyrolysis products, and changes in functional groups under different temperatures and heating rates. The pyrolysis of polyesterimide enameled wire can be divided into three stages: volatilization of specific components (314.8 °C,1.6 %), rapid decomposition of polyesterimide (435.2 °C, 44.7 %), and generation of small organic molecules with the fixation of pyrolytic carbon (750 °C, 9.0 %). The main components of the pyrolysis gas products include aromatic compounds, ethers, aromatics, ketones, and carbon dioxide. At 400 °C, a substantial amount of pyrolysis gas products and free radicals are produced, with an increase in aromatic hydrocarbons. The carbon distribution in the pyrolysis products mainly focuses on C6-C10 and C11-C15, and many organic compounds such as benzoic acid, phenol, and aniline are generated. Based on density functional theory, the bond dissociation energies in the polyesterimide were calculated. This clarified the possible thermal decomposition pathways of the polyesterimide and provided the energy barrier values, elucidating the generation mechanism of pyrolysis products during thermal decomposition. The copper atom in specific location reduces the negative ESP of O and increases the positive ESP of H in EPI, which makes H more likely to attach to O. The presence of Cu increases the ESP range and promote the pyrolysis process. This study provides a theoretical basis for the high-value recycling of waste polyesterimide enamelled wire.

Unscrambling why plastics aren't detectable in chicken eggs

Several food groups have been reported to contain varying concentrations of plastics. This study was designed to quantitatively investigate for the first time in Australia the presence of plastics in store-bought chicken eggs. Three commonly consumed brands of free-range, free-range organic, barn-laid and backyard (home-laid) chicken egg samples were analyzed for seven common polymers (i.e., polypropylene, polyethylene, polyvinyl chloride, polyethylene terephthalate, polystyrene, poly-(methylmethacrylate) and polycarbonate). Samples were extracted by enzyme digestion and pressurized liquid extraction, followed by quantitative analysis through double-shot microfurnace pyrolysis coupled to gas chromatography-mass spectrometry. No plastics were detected at concentrations > limit of detection (LOD) (from 0.04 μg/g for PS to 0.22 μg/g for PVC) in the egg samples analyzed, regardless of brand and category, suggesting limited exposure of Australians to plastics from consuming eggs This study provides valuable baseline data and underscores the importance of continued monitoring to ensure the safety and integrity of food supplies in the face of rising environmental plastic pollution.

Benzimidazole-based bimodal periodic mesoporous organosilica for thin film microextraction of triazole fungicides in fruiting vegetables prior to gas chromatography-mass spectrometry

Benzimidazole-based bimodal periodic mesoporous organosilica for thin film microextraction of triazole fungicides in fruiting vegetables prior to gas chromatography-mass spectrometry

Rapid estimation of DON content in wheat flour using close‐range hyperspectral imaging and machine learning

AbstractFusarium head blight (FHB) is one of the most destructive fungal diseases affecting wheat (Triticum aestivum). Moreover, it is notorious for producing mycotoxin deoxynivalenol (DON), posing a significant global threat to food and feed safety. Traditional methods like enzyme‐linked immunosorbent assay (ELISA) and gas chromatography‐mass spectrometry (GC‐MS) are commonly used to assess DON levels in grain or flour samples and are time‐consuming and expensive. Therefore, a faster, cost‐effective method to estimate DON content is needed, especially for enhancing breeding efforts to reduce DON levels in wheat. In this study, we envisioned integrating close‐range hyperspectral imaging with deep learning (DL) models to estimate DON content in wheat meal/flour. We selected 243 advanced breeding lines from the South Dakota State University (SDSU) wheat breeding program that were evaluated in FHB nurseries (2019–2020 and 2020–2021). The wheat meal samples were analyzed for DON content using GC‐MS and subsequently subjected to close‐range hyperspectral imaging. We evaluated three conventional machine learning (ML), two DL models and data augmentation. Among the conventional ML models, partial least squares regression (PLSR) (with R2P = 0.88 and 0.90 for original and augmented datasets, respectively) demonstrated the highest prediction accuracies for DON content. However, the one‐dimensional convolutional neural network (1D‐CNN) achieved the highest prediction accuracies (R2P = 0.90 and = 0.96 for original and augmented datasets, respectively) compared to all tested models and demonstrated the lowest error. In conclusion, integration of advanced hyperspectral imaging with ML approaches exhibits significant potential for high‐throughput and cost‐effective estimation of DON content in wheat, thereby accelerating wheat breeding efforts for reduced DON levels.

Short-chain fatty acids enhance muscle mass and function through the activation of mTOR signalling pathways in sarcopenic mice.

Sarcopenia is a prevalent muscle disorder in old people leading to higher fracture rate, mortality, and other adverse clinical outcomes. Evidence indicates that short-chain fatty acids (SCFAs), which are beneficial gut microbial metabolites, were reduced in old people with sarcopenia. This study aimed to determine whether the use of SCFAs as a supplement can be a therapeutic strategy of sarcopenia in a pre-clinical model. Seven-month-old pre-sarcopenic senescent accelerated mouse prone 8 (SAMP8) mice received daily SCFAs cocktail (acetate, butyrate, and propionate) for 3months. Age-matched senescence accelerated mouse resistant 1 (SAMR1) and SAMP8 mice receiving sodium-matched drinking water were control groups. The gut microbiota composition analysis of aged mice with or without sarcopenia was conducted by 16S rDNA sequencing. Gut barrier-related proteins and lipopolysaccharide (LPS) concentration were biomarkers of gut permeability. Colon inflammation levels, circulatory SCFAs concentration, muscle quality, function, and underlying pathways were detected by cell number counting, RT-qPCR, gas chromatography-mass spectrometry, measurements of muscle wet weight and grip strength, ex vivo functional test, treadmill endurance test, transcriptomic sequencing, morphological and immunofluorescent staining, as well as western blot. To investigate the role of mTOR signalling pathways in SCFAs treatment, C2C12 myotubes were treated with rapamycin. Aged SAMP8 mice had different microbiota composition, and lower serum butyric acid compared with SAMR1 mice (P<0.05). SCFAs treatment reversed the increment of colon inflammation (2.8-fold lower of il-1β) and gut barrier permeability (1.7-fold lower of LPS) in SAMP8 mice. Increased muscle mass, myofibre cross-sectional area, grip strength, twitch and tetanic force were found in SCFAs-treated mice compared with control SAMP8 mice (P<0.05). Anti-fatigue capacity (1.6-fold) and muscle glycogen (2-fold) also improved after SCFAs treatment (P<0.05). Transcriptomic analysis showed that AMPK, insulin, and mTOR pathways were involved in SCFAs treatment (P<0.05). Regulation of AKT/mTOR/S6K1 and AMPK/PGC1α pathways were found. SCFAs attenuated fat infiltration and improved mitochondria biogenesis of atrophic muscle. In vitro studies indicated that SCFAs inhibited FoxO3a/Atrogin1 and activated mTOR pathways to improve myotube growth (P<0.05), and rapamycin attenuated the effect of SCFAs through the inhibition of mTOR pathways. This study demonstrated that bacterial metabolites SCFAs could attenuate age-related muscle loss and dysfunction, and protein synthesis-related mTOR signalling pathways were involved both in vivo and in vitro.

Investigation of Phytochemical Composition, Radical Scavenging Potential, Anti-Obesogenic Effects, and Anti-Diabetic Activities of Kaempferia parviflora Rhizomes.

Kaempferia parviflora or commonly known as "Kunyit hitam" by locals, is an edible plant, native to tropical regions, has been extensively utilized for culinary and medicinal applications. The present study aimed to investigate the phytochemical composition and biological activities of the rhizomes of K. parviflora. The ethanol crude and fractionated extracts (hexane and chloroform) of the rhizomes were evaluated for their total phenolic content, total steroidal content, as well as antioxidant, anti-obesogenic, and anti-diabetic activities. The chloroform extract demonstrated the highest concentration of plant sterols (432±0.23 mg BSE/g extract) and a substantial amount of phenolic compounds (1.19×103±0.41 mg GAE/g extract). Gas chromatography-mass spectrometry (GC/MS) analysis revealed that the chloroform extract of the rhizomes is predominantly composed of bioactive flavonoids including tectochrysin (1), 5,7-dimethoxyflavone (2), 3,5,7-trimethoxyflavone (3), 3,4',5,7-tetramethoxyflavone (4), and 4',5,7-trimethoxyflavone (5). Furthermore, the chloroform extract exhibited the highest overall radical scavenging and α-glucosidase inhibitory activities, which can be attributed to the presence of compounds 1-5 in the extract. Collectively, these findings suggest that the chloroform extract of the rhizomes of K. parviflora is a potentially valuable source of bioactive compounds with antioxidant, anti-obesogenic, and anti-diabetic properties, with potential application in therapeutics and functional foods.

FATTY ACID COMPOSITION OF DIFFERENT COMMERCIALLY SOLD VEGETABLE OILS WITHIN SOUTHERN KADUNA, KADUNA STATE, NIGERIA

Most of the edible vegetable oils in southern Kaduna are locally processed and are available in a large commercial quantity with little known about their fatty acid (FA) content. The aim of this work was to investigate the fatty acid content of these oils and their potential impact on human health. Six commonly used edible vegetable oil samples sold in various Southern Kaduna markets were analyzed for different fatty acids content using gas chromatography-mass spectrometry (GC-MS). The result of the analysis showed differences in the contents of saturated fatty acids (SFAs), monounsaturated (MUFAs), and polyunsaturated (PUFAs). Coconut oil and kernel oil showed high content of SFAs (86.21% and 78.76%) respectively, while olive oil and peanut oil displayed significant amounts of MUFAs (75.40% and 47.62%) respectively due to high content of oleic acid (C18:1). Soybean oil with 58.06% of linoleic acid (C18:2) showed the highest total PUFA content of 65.23%. The Health Risk Index (HRI) was evaluated to assessed the impact associated with the overall intake of fatty acids in vegetable oils. The HRI were 1.78 (peanut), 0.04 (kernel), 0.23 (palm), 0.2(coconut), 4.05(soybean) and olive (0.71). Thus, soybean oil, peanut oil and olive oil have the optimum PUFA:SFA ratio according to FAO/WHO recommendations. Hence, they are recommended for mass consumption. The health promotion index (HPI) was also evaluated to assessed the content of certain essential fatty acids in various oils which have specific health benefits. The results of HPI investigation showed that only Soybean oil contains the balanced ω-6: ω-3 fatty acid ratio of 8.1 than others.

Effectiveness of co-cultured Myristica fragrans Houtt. seed extracts with commensal Staphylococcus epidermidis and its metabolites in antimicrobial activity and biofilm formation of skin pathogenic bacteria

BackgroundSkin commensal bacteria (Staphylococcus epidermidis) can help defend against skin infections, and they are increasingly being recognized for their role in benefiting skin health. This study aims to demonstrate the activities that Myristica fragrans Houtt. seed extracts, crude extract (CE) and essential oil (EO), have in terms of promoting the growth of the skin commensal bacterium S. epidermidis and providing metabolites under culture conditions to disrupt the biofilm formation of the common pathogen Staphylococcus aureus.MethodsThe culture supernatant obtained from a co-culture of S. epidermidis with M. fragrans Houtt. seed extracts in either CE or EO forms were analyzed using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS), in silico investigations, and applied to assess the survival and biofilm formation of S. aureus.ResultsThe combination of commensal bacteria with M. fragrans Houtt. seed extract either CE or EO produced metabolic compounds such as short-chain fatty acids and antimicrobial peptides, contributing to the antimicrobial activity. This antimicrobial activity was related to downregulating key genes involved in bacterial adherence and biofilm development in S. aureus, including cna, agr, and fnbA.ConclusionThese findings suggest that using the culture supernatant of the commensal bacteria in combination with CE or EO may provide a potential approach to combat biofilm formation and control the bacterial proliferation of S. aureus. This may be a putative non-invasive therapeutic strategy for maintaining a healthy skin microbiota and preventing skin infections.

Phytochemical Content towards Weak Antioxidants Activity of Traditional Fermented VCO as the Basic Ingredient for Ear Drops

Chronic Suppurative Media Otitis is caused by pathogenic bacteria, which, if the growth is not controlled, will cause meningitis and can lead to death. Virgin Coconut Oil is an oil made through the traditional fermentation process of coconut milk and can inhibit the growth of pathogenic bacteria that cause Chronic Suppurative Media Otitis. So far, pathogenic bacteria can be controlled using ear drops made from artificial chemicals, which can cause resistance. Only a few have studied the manufacture of natural-based ear drops from VCO. The purpose of this study is to study the potential of VCO as a natural essential ingredient for ear drops for patients with OMSK by analyzing its antioxidant content using the DPPH method and its phytochemical content using Ultraviolet-Visible Spectroscopy (UV-Vis) and Gas Chromatography-Mass Spectrometry (GC-MS). Its antioxidants in the IC50 (ppm) region are 583.92mg/L. The types of fatty acids contained in VCO consist of Medium-Chain Fatty Acid (MCFA), Long-Chain Fatty Acid (LCFA) and Very Long Chain Fatty Acid (VLCFA), the most of which is lauric acid (MCFA), as much as 49.28%. Conventional analysis of secondary metabolites showed the presence of Alkaloids, Terpenoids, Ascorbic Acid, and Saponins. It can be concluded that the chemical content of Virgin Coconut Oil made from fermentation can be used in the health field as a primary ingredient for making ear drops for CSOM patients.

Health Risk Assessment of Ambient Air Benzene Among Primary School Children in Urban and Rural Areas in Johor, Malaysia

Introduction: It is a fact that children are vulnerable, and are at risk from benzene, a volatile, carcinogenic organic compound. The aim of our study is to determine the levels of ambient air benzene and examine the non-carcinogenic and carcinogenic risks involved Methods: A cross-sectional study was conducted in two urban and two rural primary schools in Johor, Malaysia. Benzene concentrations were measured using BUCK Libra L-4 pumps and analyzed in the gas chromatography-mass spectrometry (GC-MS). Data were collected from 334 10-12 year old children, to calculate the exposure levels based on their body weights and heights. The hazard quotient (HQ) served to evaluate the non-carcinogenic risks, whereas the lifetime cancer risk (LCR) was determined with the aid of the United States Environmental Protection Agency (USEPA). Results and Discussion: Benzene concentrations were higher in rural than urban areas, surpassing the European Union (EU) standard of 5 μg/m³. It was also established that the highest average levels recorded were 6.89 ± 6.68 μg/m³. The HQ values, nonetheless, had indicated no immediate non-carcinogenic risk, while LCR estimates were found to be within a tolerable range across all sites. Findings showed that although the immediate risk from benzene exposure is low, long-term exposure still poses a significant cancer risk to children; even low levels of chronic exposure can heighten the likelihood of children to develop cancers. Conclusion: This study has produced a revelation that there are elevated benzene levels in rural areas in Johor. Despite the low, immediate non-carcinogenic risks, further investigation on the potential for long-term cancer risks is warranted. These risks can be addressed by conducting stricter air quality monitoring, enhancing vehicle emission standards, and introducing educational programs that can raise awareness about benzene exposure.

GC-MS-based metabonomic analysis of silkworm haemolymph reveals four-stage metabolic responses to nucleopolyhedrovirus infection.

Silkworm, Bombyx mori, an economically significant insect, plays a crucial role in silk production. However, silkworm breeding is highly susceptible to various pathogens, particularly the Bombyx mori nucleopolyhedrovirus (BmNPV), which poses a serious threat. Recent metabonomic studies have provided insights into the metabolic changes associated with BmNPV infection. BmNPV infection has obvious temporal characteristics. However, few studies have investigated the silkworms infected in different periods. This study employed gas chromatography-mass spectrometry (GC-MS) to perform a comprehensive analysis of haemolymph metabolites in silkworms at 48, 72, 96 and 120 h post-infection (h.p.i.). Through the integration of time-course analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, the study revealed distinct four-stage metabolic characteristics in the silkworm's response to BmNPV infection. At Stage 1 (48 h.p.i.), silkworms activate antioxidant defence mechanisms, with significant enrichment in metabolic pathways involving key antioxidants such as glutathione, to mitigate oxidative stress induced by viral invasion. By Stage 2 (72 h.p.i.), pathways related to amino acid metabolism and protein synthesis become active, indicating an increase in protein synthesis. In Stage 3 (96 h.p.i.), energy metabolism and substance transport pathways are significantly upregulated to support the rapid viral replication and the enhanced locomotor behaviour of silkworm. Finally, at Stage 4 (120 h.p.i.), there is a further enhancement of pathways related to energy metabolism, nucleic acid synthesis, and substance transport, which align with peak viral assembly and release. These findings contribute to an in-depth understanding of the biochemical basis of silkworm resistance to NPV.