Fatty Acid Biomarkers Research Articles

Biomarkers of polyunsaturated fatty acids and cardiovascular risk factors and events in healthy Asian populations: a systematic review.

The associations between circulating polyunsaturated fatty acids (PUFAs) and cardiovascular risk factors and events in healthy Asian populations have been less examined robustly compared to Western populations. This systematic review aimed to summarise current evidence on the associations between n-3 and n-6 PUFAs biomarkers and cardiovascular risk factors and events in healthy Asian populations. PubMed, Embase, Web of Science and Cochrane Library were searched for observational studies from January 2010 until August 2024. Twenty-three studies were eligible, which covered six Asian countries and included events(n=7), traditional risk factors such as blood pressure and lipids(n=4), physical signs such as arterial stiffness(n=4), non-traditional lipid markers(n=1), markers of inflammation(n=4), markers of thrombosis(n=2), and non-invasive imaging-based markers such as carotid intima media thickness(n=5). Biological sample type included plasma(n=6), serum(n=14) and erythrocyte(n=3). Higher circulating total n-3 PUFAs appeared to be associated with lower hypertension risk and specifically eicosapentaenoic acid and docosahexaenoic acid to be associated with lower myocardial infarction risk, reduction in triglycerides and inflammation. Higher circulating linoleic acid was associated with improved lipid profiles and lower inflammation. Limited evidence led to inconclusive associations between circulating n-6 PUFAs biomarkers and cardiovascular disease events and blood pressure. No consistent associations with arterial stiffness, obesity, thrombosis and imaging-based biomarkers were observed for circulating PUFAs biomarkers in Asian populations. Limited studies exist for each outcome, hence results should be interpreted with caution. More high quality and prospective studies in Asian populations are warranted. Several recommendations such as sample size justification and reporting of non-respondents rate are proposed for future studies.

Exploring hydrogen isotope fractionation in lipid biomolecules of freshwater algae: implications for ecological and paleoenvironmental studies

ABSTRACT Understanding the stable hydrogen isotope (δ 2H) composition and fractionation in lipid biomolecules of primary producers, such as terrestrial and aquatic plants, is crucial for deciphering past environmental conditions, as well as applying compound-specific stable isotope analysis for the study of metabolic and ecological processes. We conducted a new tracer experiment to explore the δ 2H composition of algal fatty acid biomarkers, focusing on freshwater algae, which form the base of aquatic food webs. We selected a range of algal species widely found in freshwater ecosystems and cultivated them under controlled conditions. First, we added 2H2O to ambient water as a tracer to investigate the net hydrogen isotope fractionation during algal lipid synthesis at isotopic equilibrium, which is particularly informative for paleo-geochemical studies. Then, we conducted kinetic experiments to quantify the time needed for algal fatty acids to achieve isotopic steady-state conditions in response to the change in ambient water δ 2H values. Our findings revealed substantial variability in hydrogen isotope fractionation among different algal taxa and various fatty acids. Based on taxa, different fatty acids exhibited faster integration of water hydrogen than others, but they were not necessarily in the order of the biosynthetic pathway. This experiment underscores the complexity of hydrogen isotope fractionation and the requirement for controlled laboratory studies to properly apply compound-specific stable H isotope analysis techniques in ecological and paleo-environmental studies.

Impact of different natural hosts and meridic diet on fatty acid profiling of Spodoptera litura (Fabricius) vis-à-vis reproductive physiology

Aim: This study was undertaken to document the influence of natural hosts and meridic diet on fatty acid profiling vis-a-vis reproductive physiology of Spodoptera litura (Fabricius). Methodology: S. litura were larvae fed on various hosts (castor, cauliflower, cabbage and tomato) and meridic diet. After emergence, the adults were frozen in liquid nitrogen. Fatty acid analysis was conducted by Fatty Acid Methyl Esters through gas chromatography (MIDI Sherlock, 2006). Results: One-way ANOVA and Principal component analysis (PCA) of fatty acid biomarkers from emerged adults showed that the insects reared on meridic diet had the highest percent of linoleic acid (18:2) and oleic acid (18:1) fatty acids, which are mainly responsible for insect reproduction. Interestingly, reproduction related fatty acids were distributed proportionally in case of adults emerged from meridic diet fed larvae. Interpretation: Fatty acid profile can be used as a surrogate marker to assess the reproductive fitness of insects. The study also concluded that the meridic diet would be an alternate choice in the absence of natural hosts for mass rearing of S. litura throughout the year. Key words: Fatty acid, Meridic diet, Oleicacid, Principal component analysis, Spodoptera litura

Mycorrhizal Fungal Inoculum Potential in Crop Rotation Soil With Different Levels of Irrigation

Research indicates arbuscular mycorrhizal fungi (AMF) inoculum potential and AMF biomass production in agricultural soil are strongly influenced by both soil moisture availability and crop rotation (CR) strategies. We hypothesized that AMF biomass production in and inoculum potential of Wyoming semiarid agricultural soil would increase when managed using CR and irrigation. To test this hypothesis, we examined AMF activity (AMF biomarker fatty acid, and AMF infection of roots) in two differently managed soils (no-CR soil and two-year CR soil) in a field experiment. Furthermore, in a greenhouse experiment, we examined AMF activity in the same two CR treatment soils under different irrigation regimes (wet, irrigated to 60% field capacity, and dry, irrigated to 15% field capacity). Notably, the two-year CR soil had greater amounts of AMF biomarker fatty acid and greater inoculum potential, and higher percentage of AMF root colonization compared to no-CR soil. Despite the fact that the CR soil had more AMF propagules, it was less than the undisturbed non-agricultural native sage-grassland soils previously reported. Overall, the findings suggest that high levels of irrigation can inhibit the activity of AMF adapted to semiarid soil conditions and CR can increase activity of AMF in soils from semiarid regions.

Ocean conditions influence the quality of recruiting benthic marine invertebrate larvae—Insights from fatty acids

AbstractMany marine benthic invertebrates have a pelagic life stage, during which larvae need to accumulate enough reserves to complete metamorphosis to a settled benthic juvenile. Currently, very little is known about how ocean conditions affect quality of the larvae. We studied this for three settlement seasons (2017–2019) by collecting returning Dungeness crab (Metacarcinus magister) megalopae at the Oregon coast and analyzing them for fatty acid biomarkers. We found that the larvae are omnivorous and have versatile diets. The daily larval abundance was positively correlated with larval quality. Despite the relatively high day‐to‐day variation, we found pronounced seasonal and inter‐annual differences in the body condition (size and total fatty acid content) and biomarker composition of megalopae. Especially, the early season recruits of 2017 had lower content of lipids and polyunsaturated fatty acids known to be beneficial to crustaceans. This is likely related to lingering effects of the eastern Pacific marine heat wave (2014–2016) on pelagic communities. The larvae were rich in docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) with lower levels in benthic juveniles, indicating an ontogenetic diet shift and likely lower availability of DHA and EPA in the benthic environment. The pulsed megalopa recruitment may provide substantial carbon and lipid inputs to the nearshore ecosystem as a form of pelagic subsidy. Our results reveal that ocean conditions may have an effect on the quality of returning larvae, which likely influence their recruitment performance and early juvenile success, and thus potentially also the population size and commercial catch 4 yr later.

Quantitative and Qualitative Relationships between Phospholipid Fatty Acid Analysis Biomarkers and Lignin in Soil from the Tibetan Plateau (China) under Laboratory Incubation Conditions

Lignin, an organic compound with a complex structure, is formed through the polymerization of structural units linked by carbon–carbon bonds and ether bonds. The question of whether lignin is labile or resistant to biological and chemical degradation in soil, particularly in alpine ecosystems, remains unresolved. To address this knowledge gap, we analyzed the relationship between phospholipid fatty acid biomarkers and the abundance of lignin components in grassland soils from North Tibet, China. Soil samples were collected from alpine grasslands, including alpine meadows and alpine steppes. The relative abundance of lignin in these alpine grassland soils before and after a 210-day incubation period was measured. Our results indicate that the relative abundance of lignin in the alpine grassland soils decreased during the incubation period. Significant relationships were found between the phospholipid fatty acid biomarkers of bacteria, fungi, Gram-positive bacteria, and Gram-negative bacteria and the relative abundance of lignin components. This research was conducted under laboratory conditions that are optimal for the development of microorganisms but significantly different from the conditions in Tibet. Furthermore, this study contributes to the understanding of soil organic matter degradation and the dynamics of microbial communities in alpine grassland soils in the context of future global warming.

Application of microdialysis combined with lipidomics to analyze fatty acid metabolic changes in the disease process of rheumatoid arthritis

Rheumatoid arthritis (RA) is a metabolically active disease, with shifts in fatty acid metabolism during disease progression profoundly affecting the systemic inflammatory response. Altered fatty acid biomarker metabolism may be a key target for the treatment of RA. To investigate the changes of fatty acid metabolism in RA, collagen-induced arthritis (CIA) model was established. Microdialysis sampling was utilized to overcome the characteristic of occlusive joint cavity in vivo synovial fluid (SF) sampling. Lipidomic methods were established with the UHPLC-Orbitrap Exploris120 platform, and lipid measurements were performed on serum and SF samples. Then, multivariate statistical analyses were performed to detect changes in lipid metabolites induced by CIA. Consequently, a total of 22 potential biomarkers associated with differential fatty acids were screened and identified in serum, and 13 were identified in SF. Notably, alterations were observed in metabolites such as Hexadecanoic acid, Octadecanoic acid, Arachidonic acid, (+/-)11,12-EpETrE, DHA, DPA, Myristic acid, Suberic acid, and others. This study explored a new mechanism of the RA disease process from the perspective of fatty acid metabolism. It provided a new strategy for experimental research on determining the optimal time for establishing CIA model and screening clinical diagnostic biomarkers.

Evaluation of fate of organic matter in sediment through microcosm experiments

AbstractLaboratory microcosm experiments help to understand the degradation pattern of different sources derived from organic matter (OM) at the sediment–water interface and relate it to field processes. Microcosm experiments were carried out for 65 days to assess the degradation of organic materials such as diatoms, zooplankton, and mangrove leaves using source‐specific fatty acid (FA) biomarkers. The viable bacterial population in the microcosm sediment was low on day 1, but on day 3, it increased substantially by two to threefold in all the treatments. An increase in the bacterial population resulted in a decrease in the FAs specific to organic materials during the initial incubation phase (10 days), suggesting the degradation of organic materials derived from different sources. The FAs specific to diatoms showed faster degradation when compared to zooplankton and mangrove‐specific FAs. The degradation of FAs was influenced by the nature of the source material, unsaturation of FAs, and the sediment type. Sandy sediment facilitated higher degradation of diatom and zooplankton‐specific FAs, whereas mangrove‐specific FAs showed higher degradation in silty‐clay sediment. Thus, bacterial community composition coupled with the habitat characteristics, the OM composition, and the grain size of the sediment, influenced the degradation of FAs. The degradation of mangrove‐specific long‐chain FAs was ~1.11–2.5 times higher when spiked with plankton‐derived labile OM from mixed sources, which otherwise took a longer time for degradation pointing toward co‐metabolism (priming effect), which could play a significant role in the cycling of terrestrial plant‐derived OM in an estuarine ecosystem.

Lipidomic and Fatty Acid Biomarkers in Whole Blood Can Predict the Dietary Intake of Eicosapentaenoic and Docosahexaenoic Acids in a Danish Population

BackgroundThe intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been associated with health benefits. Blood levels of these fatty acids, measured by gas chromatography (GC), are associated with their dietary intake, but the relationships with lipidomic measurements are not well defined. ObjectivesThis study aimed to determine the lipidomic biomarkers in whole blood that predict intakes of EPA + DHA and examine the relationship between lipidomic and GC-based n–3 polyunsaturated fatty acid (n–3 PUFA) biomarkers. MethodsLipidomic and fatty acid analyses were completed on 120 whole blood samples collected from Danish participants. Dietary intakes were completed using a web-based 7-d food diary. Stepwise multiple linear regression was used to identify the fatty acid and lipidomic variables that predict intakes of EPA + DHA and to determine lipidomic species that predict commonly used fatty acid biomarkers. ResultsStepwise regression selected lipidomic variables with an R2 = 0.52 for predicting EPA + DHA intake compared to R2 = 0.40 for the selected fatty acid GC-based variables. More predictive models were generated when the lipidomic variables were selected for females only (R2 = 0.62, n = 68) and males only (R2 = 0.72, n = 52). Phosphatidylethanolamine plasmalogen species containing EPA or DHA tended to be the most predictive lipidomic variables. Stepwise regression also indicated that selected lipidomic variables can predict commonly used fatty acid GC-based n–3 PUFA biomarkers as the R2 values ranged from 0.84 to 0.91. ConclusionsBoth fatty acid and lipidomic data can be used to predict EPA + DHA intakes, and fatty acid GC-based biomarkers can be emulated by lipidomic species. Lipidomic-based biomarkers appear to be influenced by sex differences, probably in n–3 PUFA and lipoprotein metabolism. These results improve our ability to understand the relationship between novel lipidomic data and GC fatty acid data and will increase our ability to apply lipidomic methods to fatty acid and lipid nutritional research.

Plasma Branched-Chain Fatty Acids Reflect Dairy-Fat Intake in a Pilot Clinical Trial in Individuals with Prediabetes

Epidemiological studies often rely on fatty acid (FA) biomarkers of dairy-fat intake to represent diet history and to establish associations with cardiometabolic risk factors. However, a more robust body of direct research is needed to validate the currently utilized FA biomarkers as accurate representations of dairy-fat intake. Thus, our objectives were to i) compare the plasma FA profile of individuals with prediabetes following the consumption of a diet with full-fat (3.25%) yogurt (FFY diet) or non-fat yogurt (NFY diet) to evaluate their validity of currently utilized biomarkers and ii) identify additional FAs to serve as potential biomarkers. We hypothesized that the proportion of the unique dairy-derived FAs including odd-chain FAs (13:0, 15:0, 17:0, 19:0, 21:0, 23:0), branched-chain FAs ( iso-13:0, anteiso-13:0, iso-14:0, iso-15:0, anteiso-15:0, iso-16:0, iso-17:0, anteiso-17:0, iso-18:0), and the trans-FAs 16:1 trans-9 and 18:1 trans-11 would increase in plasma total lipids following the consumption of three daily servings of full-fat yogurt for three weeks. Our 8-week randomized, double-masked, controlled crossover study included six men and seven women aged 45-75 years old. Each experimental diet period, NFY diet and FFY diet, was three weeks in length. The arithmetic difference in fat (8% energy) between the NFY diet (30% fat) and the FFY diet (38% fat) was solely due to the dairy fat in the full-fat yogurt. Following each experimental diet period, fasting plasma samples were taken and analyzed for FA composition of plasma total lipids using gas-liquid chromatography. Consumption of the FFY diet resulted in no change in the proportion of total odd-chain FAs or the individual FAs 16:1 trans-9 and 18:1 trans-11, but the proportion of total branched-chain FAs was greater in response to the FFY diet ( P < 0.01). For individual odd-chain and branched-chain FAs, the proportions of iso-17:0 and anteiso-17:0 were greater in response to the FFY diet ( P < 0.01 for both); however, there were no differences in anteiso-15:0 or iso-15:0 proportions by diet. Results from this pilot trial suggest that commonly utilized FA biomarkers may not be suffciently robust to represent dairy-fat intake. Branched-chain FAs should be further explored for alternatives. Funding for this project was provided by National Dairy Council Nutrition Research Funding, a USDA Agriculture and Food Research Initiative National Institute of Food and Agriculture Predoctoral Fellowship, and a fellowship from the University of Vermont’s Food Systems Research Center. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Association of plasma trans fatty acid concentrations with blood pressure and hypertension in U.S. adults.

The present study aimed to evaluate the association of plasma trans fatty acids (TFAs) biomarkers with the risk of hypertension. Using data from the National Health and Nutrition Examination Surveys (NHANES 2009-2010), we conducted a thorough analysis using both the traditional regression model and the Bayesian Kernel Machine Regression (BKMR) model to investigate the associations of individual TFAs and their mixtures with systolic blood pressure (SBP), diastolic blood pressure (DBP), and the risk of hypertension in a sample of 1,970 American adults. The concentrations of TFAs were natural logarithms (ln) transformed to approximate a normal distribution. Multivariate linear regression models showed that each 1-unit increase in ln-transformed plasma concentrations of palmitelaidic, elaidic, vaccenic, and linolelaidic acids was associated with separate 2.94-, 3.60-, 2.46- and 4.78-mm Hg and 2.77-, 2.35-, 2.03-, and 3.70- mm Hg increase in SBP and DBP, respectively (P < 0.05). The BKMR model showed positive associations between the four TFAs mixtures and SBP and DBP. In addition, linolelaidic acid contributed the most to an increased blood pressure. Similar results were observed with the threshold of hypertension (≥130/80 mm Hg). Our findings provide preliminary evidence that plasma TFA concentrations are associated with increased blood pressure and the risk of hypertension in US adults. This study also suggests that linolelaidic acid might exhibit more deleterious effects on hypertension than other TFAs. Further studies should be conducted to validate these results.

Machine learning strategy for light lamb carcass classification using meat biomarkers

In Mediterranean areas, lamb meat is considered to be of great commercial value. Moreover, consumers are becoming increasingly interested in understanding the origin of lamb meat and its associated production and breeding systems. Among many applications, algorithms based on artificial intelligence are used to identify the origin of food products, and in this context, algorithms such as the Support Vector Machine (SVM), K-Nearest Neighbours (KNN), and the Artificial Neural Network (ANN) have been proposed to differentiate the origin of the animals according to their feeding diet. The objective of this study was to evaluate the performance of a variable reduction method based on a multiple regression model and three widely-used machine learning algorithms (SVM, KNN and ANN) for the classification of three commercial light lamb carcasses, from three feeding diets, in an indigenous Spanish breed (Mallorquina), using fatty acid and volatile compound biomarkers of meat. Machine learning algorithms were employed to discriminate lamb carcasses using 14 identified significant biomarkers, which were arranged based on an estimation of the relative importance (stepwise forward multiple regression F-score) of the input variables. We achieved high performances for the SVM, KNN and ANN algorithms, with 86%, 98% and 98% prediction accuracy, respectively. Among the 14 biomarkers used, 7 were identified as showing the highest discriminant capacity. The F-scores indicate that C17:1 and C20:5 n-3 fatty acids, and 2,5-dimethylpyrazine and 3-methylbutanal volatile compounds are the four most relevant biomarkers for predicting three lamb feeding diets.

Fatty Acid Intake and Polyunsaturated Fatty Acid Biomarkers and Risk of Total Knee or Hip Arthroplasty Among Older Women in the Women's Health Initiative.

The objective was to determine whether baseline fatty acid intake and erythrocyte omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) can predict risk of total hip arthroplasty (THA) and total knee arthroplasty (TKA) in older women. This was a prospective analysis of 34,990 women in the Women's Health Initiative. Dietary fatty acids were estimated from food frequency questionnaires. Imputed erythrocyte PUFAs were available in a subcohort of 3,428 women. Arthroplasty (THA and TKA), used as a surrogate of severe osteoarthritis, was identified via linked Medicare data. Cox proportional hazards models were constructed to estimate risk of arthroplasty. Risk of THA was associated with higher intake of arachidonic acid, (multivariable hazard ratio [HR] quartile 4 [Q4] vs Q1: 1.16; 95% confidence interval [CI] 1.01-1.34; P = 0.03) and higher intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA; HR Q4 vs Q1: 1.20; 95% CI 1.05-1.39; P = 0.003). There was a linear trend (P = 0.04) for patients to have a higher risk of THA with higher erythrocyte EPA and DHA in body mass index-adjusted models; however, there was no significant difference in patients who had THAs by quartiles of erythrocyte EPA and DHA (P = 0.10). Dietary fatty acids and erythrocyte PUFAs were not significantly associated with risk of TKA. Higher baseline intakes of arachidonic acid and EPA and DHA were associated with a modestly higher risk of THA. No association was found between fatty acids and patients who had TKAs. Further research in populations with direct measures of osteoarthritis severity is needed to better understand the importance of PUFAs in modulating osteoarthritis and arthroplasty risk.

High-throughput sequencing and fatty acid profile analyses of the Black Amur bream (Megalobrama terminalis) reveal variation in dietary niche associated with geographic segregation.

Fish dietary niche is a core focus, and it reflects the diversity of resources, habitats, or environments occupied by a species. However, whether geographic segregation among different populations triggers dietary diversification and concomitant fish niche shift remains unknown. In the present study, we selected the Black Amur bream (Megalobrama terminalis) is a migratory fish species that plays an important role in the material transfer and energy cycling of river ecosystems, inhabiting southern China drainage with multiple geographic populations. Here, we utilized the combined analyses of 18S rDNA high-throughput sequencing in fish gut contents and fatty acid (FA) in muscle tissues to evaluate potential spatial patterns of habitat and resource use for M. terminalis in three rivers of southern China. Our results showed that prey items of the Xijiang (XR) population (Pearl River) exhibited the highest species diversity and richness among the three geographic populations. Moreover, diet composition of M. terminalis was affected by spatial differences associated with geographic segregation. Analyses of FA biomarkers indicated that the highest levels of C16:0, C18:3n-3, and C18:2n-6c were found in Wanquan (WS) population (Wanquan River). The XR population exhibited a distinct FA profile characterized by higher amounts of arachidonic acid (ARA) and docosahexaenoic acid (DHA). The Moyang (MY) population (Moyang River) acted as the linkage between WS and XR populations and consisted of middle levels of saturated FAs (SFAs) and polyunsaturated FAs (PUFAs). The XR population displayed a greater FA niche width compared with WS population. Furthermore, we observed a close positive relationship between the niche width and α-diversity indices of dietary resources for FA proflies. Our study provides valued information to develop different conservation strategies among different populations and improve fisheries management for M. terminalis and other endemic species in local rivers.

The Roles of Diet and Habitat Use in Pesticide Bioaccumulation by Juvenile Chinook Salmon: Insights from Stable Isotopes and Fatty Acid Biomarkers.

Stable isotopes (SI) and fatty acid (FA) biomarkers can provide insights regarding trophic pathways and habitats associated with contaminant bioaccumulation. We assessed relationships between SI and FA biomarkers and published data on concentrations of two pesticides [dichlorodiphenyltrichloroethane and degradation products (DDX) and bifenthrin] in juvenile Chinook Salmon (Oncorhynchus tshawytscha) from the Sacramento River and Yolo Bypass floodplain in Northern California near Sacramento. We alsoconducted SI and FA analyses of zooplankton and macroinvertebrates to determine whether particular trophic pathways and habitats were associated with elevated pesticide concentrations in fish. Relationships between DDX and both sulfur (δ34S) and carbon (δ13C) SI ratios in salmon indicated that diet is a major exposure route for DDX, particularly for individuals with a benthic detrital energy base. Greater use of a benthic detrital energy base likely accounted for the higher frequency of salmon with DDX concentrations > 60ng/g dw in the Yolo Bypass compared to the Sacramento River. Chironomid larvae and zooplankton were implicated as prey items likely responsible for trophic transfer of DDX to salmon. Sulfur SI ratios enabled identification of hatchery-origin fish that had likely spent insufficient time in the wild to substantially bioaccumulate DDX. Bifenthrin concentration was unrelated to SI or FA biomarkers in salmon, potentially due to aqueous uptake, biotransformation and elimination of the pesticide, or indistinct biomarker compositions among invertebrates with low and high bifenthrin concentrations. One FA [docosahexaenoic acid (DHA)] and DDX were negatively correlated in salmon, potentially due to a greater uptake of DDX from invertebrates with low DHA or effects of DDX on FA metabolism. Trophic biomarkers may be useful indicators of DDX accumulation and effects in juvenile Chinook Salmon in the Sacramento River Delta.

Abstract MP37: Insomnia is Associated With Fatty Acid and Oxylipin Inflammatory Biomarkers in the Hispanic Community Health Study/Study of Latinos

Introduction: Insomnia symptoms are prevalent in Hispanic/Latino adults, and insomnia is a risk factor for cardiometabolic disease, possibly through dysregulated inflammatory pathways. However, existing evidence has largely focused on non-specific and downstream inflammatory biomarkers. Informed by prior research, we hypothesized that insomnia promotes chronic low-grade inflammation by disrupting the physiological balance between upstream bioactive fatty acids and oxylipins. Objective: To evaluate associations between insomnia and 81 upstream bioactive fatty acid and oxylipin inflammatory biomarkers in the population-based Hispanic Community Health Study/Study of Latinos (HCHS/SOL). Methods: After excluding night and rotating shift workers, participants were 14,439 HCHS/SOL adults (mean age: 46 y, 61% female, 62% with education ≥ high school degree). Insomnia was measured using the Women’s Health Initiative Insomnia Rating Scale (WHIIRS). We used the WHIIRS score as a continuous (range 0-20, with higher scores indicating greater severity) and categorical variable (WHIIRS ≥ 9, indicating clinically significant insomnia). The 81 oxylipins and fatty acids were profiled in fasting blood samples using non-targeted liquid chromatography-mass spectrometry and annotated based on mass-to-charge ratio, retention time, and spectra. Cross-sectional associations between rank normalized oxylipins and fatty acids with insomnia were assessed using survey-weighted multivariable linear regression adjusting for confounders (age, sex, center, Hispanic background group, education, smoking, alcohol use, the alternative healthy eating index, physical activity, and body mass index). We addressed multiple comparisons using a false discovery rate &lt;0.05. Results: The mean WHIIRS score was 7.1 (standard deviation: 5.4) and 36% displayed clinically significant insomnia. The WHIIRS showed statistically significant positive associations with 7 fatty acids (nervonic, docosadienoic, palmitoleic, eicosanoic, docosaenoic, behenic, and lignoceric acid) and 4 oxylipins (HpODE, leukotriene/HpETE/DiHETE/prostaglandin, HOTrE/oxoODE, and an oxylipin with unknown biological pathway). Clinically significant insomnia defined categorically showed statistically significant positive associations with 3 fatty acids and 3 oxylipins, all of which were also identified in the continuous WHIIRS analysis (see above). Identified fatty acids and oxylipins included both putative pro-inflammatory (e.g., HpODE) and anti-inflammatory (e.g., nervonic acid) compounds. Conclusions: Insomnia, like cardiometabolic disease, is associated with low-grade inflammation. The directionality of these relationships and degree to which associations between chronic inflammation with cardiometabolic disease and insomnia reflects overlapping pathways warrants further investigation.

Spatial heterogeneity of sedimentary organic matter sources in the Yangtze River estuary: Implications from fatty acid biomarkers

This study investigated the sources of sedimentary organic matter (OM) in the Yangtze River estuary (YRE), using multiple biomarkers. The results of stable carbon isotope (δ13C) and total organic carbon to nitrogen ratio (TOC/TN) suggests the contribution of marine-derived OM significantly increased seawards, while fatty acid (FA) composition provides more specific information on OM sources. In total, 30 components of FAs were identified at the studied 17 sites, which mainly composed of phytoplankton FA, followed by ubiquitous FA and bacterial FA, while terrestrial FA contributed less to the total FAs. Under the strong impacts of the large physicochemical gradients in the YRE, TOC, TN and FA components showed higher concentrations in the estuary mixing zone (especially within the turbidity maximum zone), attributing to their strong binding with OM-enriched fine particles. The spatial heterogeneity of sedimentary OM sources was highly impacted by salinity and Chl-a, as well as bacteria-mediated OM degradation.

Toward soil carbon storage: The influence of parent material and vegetation on profile-scale microbial community structure and necromass accumulation

Soil microbial communities play a crucial role in the accumulation and stabilization of soil organic carbon (SOC) through complex processes involving plant residue transformation and mineral interactions. These processes are influenced by plant inputs and modulated by soil properties that are mostly determined by the parent material. However, our understanding is limited regarding the manner in which vegetation and parent material affect microbial community structure, necromass accumulation, and their subsequent impact on SOC storage. To bridge this knowledge gap, we conducted an in-depth investigation focusing on the top-down influence of vegetation type and the bottom-up effect of parent material on microbial-mediated carbon transformation across soil profiles in a tropical region. Our study encompassed 42 sites on three parent materials (basalt, granite, and marine sediments) and four vegetation types (rubber, banana, areca plantations and uncultivated grassland). Soil samples were collected at 0–20, 20–40, 40–80, and 80–100 cm depth. Microbial community structure and necromass were quantified using microbial biomarkers of phospholipid fatty acids and amino sugars, respectively. In rubber plantations, we observed a trend toward higher microbial biomass that, though not significant when compared to other vegetation types, transformed to a significantly higher accumulation of microbial necromass. This increase in microbial necromass was linked to the accumulation of SOC facilitated by the presence of clay size minerals in clayey soils developed from basalt. In particular, basaltic soils were dominated by bacteria, which facilitated the accumulation of bacterial necromass that significantly bolstered its contribution to SOC. In contrast, in sandier soils developed from granite and marine sediments, fungal communities and necromass dominated due to the propensity of fungi for coarser soil environments. Overall, the main impact of vegetation on microbial communities and necromass accumulation was primarily demonstrated for the topsoil. Differences in soil texture arising from different parent materials exert significant effects on the fungal-to bacterial-biomass and necromass ratios, consequently influencing the contribution of fungal and bacterial necromass carbon to SOC across soil profiles. Our study underscores the pivotal role of parent material in governing tropical profile-scale soil carbon storage by shaping the structure of microbial communities and influencing the retention of microbial necromass.

Tracing transgenerational plasticity through ova fatty acid biomarkers in Giant Kōkopu (Galaxias argenteus)

ABSTRACT Broodstock management has traditionally focused on heritable traits and diet-induced gamete quality. However, the potential of transgenerational plasticity (TP) underscores the importance of understanding adaptive trait transfer in aquaculture, where the sustainability of production can be hampered by mortality arising from disease and stress. Notably, the role of fatty acids (FAs) as important biomarkers is an untapped area of TP research with implications for the management of new aquaculture species. We assessed TP in Giant Kōkopu (Galaxias argenteus) by comparing the ova FA profiles of broodstock across five captive generations; wild-caught, F1, and three successive F2s. Our study revealed intergenerational shifts in ova FA profiles. We encountered a significant decline in C18:1 (n-9) (Oleic Acid, OLA) and C20:4 (n-6) (Arachidonic acid, ARA), and an increase in C16:0 (Palmitic acid, PAL) from wild-caught to captive-bred broodstock. These shifts reveal that latter generations of captive-bred G. argenteus are reducing the provision of FAs associated with stress (OLA) and lower reproductive success (ARA), while increasing those linked to improved immune response (PAL), signalling a significant adaptation to captivity. Our findings help elucidate the theoretical understanding of TP through the use of FAs as biomarkers, providing practical insight for broodstock management.

Effect of physical exercise on immune, inflammatory, cardiometabolic biomarkers, and fatty acids of breast cancer survivors: results from the MAMA_MOVE Gaia After Treatment trial.

Physical exercise has positive effects on clinical outcomes of breast cancer survivors such as quality of life, fatigue, anxiety, depression, body mass index, and physical fitness. We aimed to study its impact on immune, inflammatory, cardiometabolic, and fatty acids (FA) biomarkers. An exploratory sub-analysis of the MAMA_MOVE Gaia After Treatment trial (NCT04024280, registered July 18, 2019) was performed. Blood sample collections occurred during the control phase and at eight weeks of the intervention phase. Samples were subjected to complete leukocyte counts, cytokine, and cardiometabolic marker evaluation using flow cytometry, enzyme-linked immunoassays, and gas chromatography. Ninety-three percent of the 15 participants had body mass index ≥ 25kg/m2. We observed a decrease of the plasmatic saturated FA C20:0 [median difference - 0.08% (p = 0.048); mean difference - 0.1 (95%CI - 0.1, - 0.0)], positively associated with younger ages. A tendency to increase the saturated FA C18:0 and the ratio of unsaturated/saturated FA and a tendency to decrease neutrophils (within the normal range) and interferon-gamma were observed. Positive trends of physical exercise on circulating immune cells, inflammatory cytokines, and plasmatic FA were observed. Larger studies will further elucidate the implications of physical exercise on metabolism. These exploratory findings may contribute to future hypothesis-driven research and contribute to meta-analyses.