Phospholipid Fatty Acid Profiles Research Articles

Short‐term effects of Kernza and alfalfa on microbial communities

AbstractContinuous land disturbance could negatively impact microbial community, but perennial crops can potentially reverse this negativity. The objective of this study was to evaluate the effects of Kernza (Thinopyrum intermedium) and alfalfa (Medicago sativa L.) on soil microbial structure and stress condition using the phospholipid fatty acid profiling. The study was conducted at the Ross Jones Research Farm, University of Missouri and consisted of four treatments: Kernza fertilized, Kernza unfertilized, Kernza and alfalfa intercrop, and alfalfa monocrop with four replications. Treatments were established in September 2021 on 18.3 m × 18.3 m plots. Soils from 0‐ to 5‐cm and 5‐ to 15‐cm depths were sampled in September 2021 (before treatments were placed) and 2022 and analyzed for microbial communities. All microbial communities increased after 1 year with the perennial crops. Since differences were not significant among treatments in 2022, this may lead to positive impacts of perennial crops on microbial communities, irrespective of the crop species and management. Moreover, community structure modifications were also observed with the perennial crops, irrespective of the species and management, as evidenced with changes in bacterial community indices in 2022. While fungi/bacteria ratio increased, Gram‐positive/Gram‐negative bacteria ratio decreased in 2022, suggesting a reduction in microbial stress, which can be attributed to ecological functions of the perennial crops. The study showed improvements in soil microbial biomass and modifications in microbial community structure after 1 year of Kernza and alfalfa. As the system matures, relative benefits of management (fertilization and intercropping) and plant species may be realized.

Exposure to a Combination of Fusarium Mycotoxins Leads to Lipid Peroxidation and Influences Antioxidant Defenses, Fatty Acid Composition of Phospholipids, and Renal Histology in Laying Hens.

The effects of combined short-term (3 days) exposure to Fusarium mycotoxins at both the EU recommended limit (T-2/HT-2 toxin: 0.25 mg/kg; DON/3-AcDON/15-AcDON: 5 mg/kg; FB1: 20 mg/kg) and twice the dose (T-2/HT-2 toxin: 0.5 mg/kg, DON/3-AcDON/15-AcDON: 10 mg/kg, and FB1: 40 mg/kg feed) on the kidneys of laying hens were examined. Our study aimed to investigate how these mycotoxins interacted with membrane lipid fatty acid (FA) composition and lipid peroxidation processes. It was observed that the levels of conjugated dienes and trienes were higher than the control in the low-mix group on day 3, and malondialdehyde concentration was higher on days 2 and 3. The proportion of phospholipid (PL) FAs showed that saturated and monounsaturated FAs increased. Still, both n3 and n6 polyunsaturated FAs decreased significantly on day 2 of exposure in the high-mix group. Among the n3 FAs, the level of docosahexaenoic (C22:6 n3) and among n6 FAs, arachidonic (C20:4 n6) acids decreased mainly on day 2 in the high-mix group. The results suggest that the combined exposure to Fusarium mycotoxins induced lipid peroxidation in the kidneys of laying hens, which resulted in marked changes in the PL FA profile. Histological examination revealed time- and dose-dependent increases as consequences of mycotoxin exposure.

Erythrocyte Phospholipid Fatty Acid Profile in High-Level Endurance Runners

Fatty acids (FAs) are the major structural component of erythrocyte membranes. Diet and physical exercise directly influence their incorporation and function. Endurance runners engage in high volumes of weekly aerobic training, alternating between low-intensity and high-intensity sessions. The aim of the study was to assess and compare the erythrocyte FA profile in a group of high-level male endurance runners (EG) with a control group of non-athlete subjects (CG). This observational study was conducted on 85 subjects, 63 high-level male endurance runners (23 ± 3 years; height: 1.76 ± 0.05) and 22 subjects who did not engage in regular physical exercise (21 ± 0.5 years; height: 1.68 ± 0.39). Runners had at least five years of training experience, and all of them were participants in national and international tournaments. FAs determination was performed using gas chromatography. Higher percentages of Palmitic Acid (PA), Stearic Acid (SA), Oleic Acid (OA), Calendic Acid (CA), Eicosapentaenoic Acid (EPA) and Docosapentaenoic Acid (DPA), and lower percentages of Docosahexaenoic Acid (DHA) were found in the EG compared to the CG. High-level endurance runners exhibit altered erythrocyte FA profiles with low percentages of omega-3 index (ω-3 index) and DHA, which may affect erythrocyte membrane function as well as their performance.

An experimental model of western diet in female Wistar rats leads to cardiac hypoxia related to a stimulated contractility.

Previous studies in Western diet (WD)-fed male rats have highlighted a link between the stimulation of cardiac contractility, mitochondrial adaptations and a pro-inflammatory fatty acid profile of phospholipids in the heart. Our objectives were to determine (1) if WD-fed female Wistar rats and obese humans display a similar pro-inflammatory profile in their cardiac phospholipids and (2) if this lipid profile is associated with deleterious effects on the heart of the female rodents. Female Wistar rats were fed WD for 5weeks or a laboratory chow as a control. Ionic homeostasis, redox status, inflammation markers, and fatty acid composition of phospholipids were analysed in the heart. WD increased the abdominal fat mass without modifying the body weight of female rats. As previously found in males, a WD induced a shift in membrane fatty acid composition toward a pro-inflammatory profile in the female rats, but not in obese humans. It was associated with an increased COX2 expression suggesting an increased pro-inflammatory eicosanoid production. Signs of increased intracellular calcium strongly supported a stimulation of cardiac contractility without any induction of apoptosis. The heart of WD-fed rats exhibited a hypoxic state as a higher HIF1-α expression was reported. The expressions of antioxidant enzymes were increased, but the redox reserves against reactive oxygen species were lowered. In conclusion, as previously observed in males, we suppose that cardiac abnormalities are magnified with severe obesity in female rats, leading to hypoxia and intense oxidative stress which could ultimately induce cell death and heart failure.

Microbial Diversity, Biomass, and Community Structure Differences among Restored and Natural Saltwater Marshes, Louisiana

Tidally influenced, saltwater marsh construction projects are being completed in Louisiana to combat coastal erosion and land loss, as well as to restore critical fisheries and counteract ecosystem injuries caused by oil spills and other anthropogenic activities. Historically, metrics of success for restored marshes have been based on the amount of aboveground biomass, survival of planted vegetation, and recruitment of local endemic versus invasive species. The microbial communities responsible for cycling nutrients within restored soils are not typically evaluated. Therefore, we investigated microbial community structure, biomass, and diversity in marsh soils that had been created from nearby dredge material over the past 10 years in the Lake Hermitage, West Point a La Hache area, and compared the results to those from natural marsh soils from Bay Batiste, as determined using phospholipid fatty acid (PLFA) and gas chromatography/mass spectrometry (GC/MS) techniques and from 16S rRNA gene profiles. Soils were collected from two depths (0-2 cm and 8-10 cm) from four sampling locations along a 100-m transect that extended inland from the coastline. Soil organic carbon content and soil pH were consistently lower at restored sites compared to natural marshes. Natural marsh soil microbial diversity strongly correlated with the biomass of typical marsh plants (e.g., Spartina alterniflora, Juncus roemerianus), whereas restored soil diversity correlated to higher Paspalum spp. (crowngrass) and Schoenoplectus pungens (common bulrush) biomass. Created soils had higher overall microbial diversity, but natural marsh soils had at least twice as much PLFA biomass than the created marshes at the shallow depth and 10X more biomass at the deeper depth. Biomass estimates ranged from below detectable levels to 6 x104 pmol PLFA gdw−1, with shallower soils from all sites exhibiting higher biomass (average 104 pmol PLFA gdw-1) compared to deeper soils (average 103 pmol PLFA gdw-1). Diverse PLFA profiles were observed. Shallow soils were dominated by terminally-branched and midchain-branched saturates that are indicative of Gram-positive microorganisms and actinomycetes. The shallow soils contained polyunsaturates indicative of phototrophs. Deeper soil profiles were dominated by monounsaturates associated with Gram-negative bacteria and sulfate- and metal-reducing bacteria. These monounsaturates contained on average 7% of the total PLFA profile as cyclopropyl fatty acids, which likely indicated anaerobic processes and the presence of nutritional stress. The shallow natural marsh soils exhibited more mid-branched saturates, branched monounsaturates, and polyunsaturates, whereas the shallow created marsh soils had more terminally-branched saturates. In the deeper soils, the natural marshes exhibited more terminally-branched saturates and monounsaturates, but the created marshes contained more saturates. GC/MS analyses of dimethyl disulfide derivatizations revealed shifts in microorganisms, as indicated by the types and bonding positions of monounsaturates, and the changes in the presence/absence of methanotrophic populations within the soils, which was also reflected in the 16S rRNA gene profiles. From these results, the microbial communities from the created marsh soils were different than the natural soil communities, and may reflect not being the best desired outcome for marsh restoration. With time, the expectation would be that created marsh above and belowground microbial diversity and biomass would begin to mimic natural marshes, but continued monitoring through time will be necessary to understand how these linkages develop and affect basic soil processes, nutrient cycling, and recruitment and sustenance of higher organisms like fish or crustaceans.

Exploring Biomarker Signatures in Glaciovolcanic Environments: Implications for the Search for Life on Mars

Glaciovolcanic systems, where hydrothermal heat interacts with ice, offer favorable conditions for life by providing liquid water, nutrients, and physicochemical gradients (Cousins and Crawford 2011). Despite significant climate change, evidence for glaciovolcanism is widespread through Mars’ history. Such sites may have offered refugia for life after Mars lost much of its surface water, representing some of the most recent habitable areas and promising sites to recover biomarkers. We examined a terrestrial glaciovolcanic site to study the indigenous biological community structure, the supporting physicochemical parameters, and the distribution of biomarkers within the geologic context. The insights will help refine Mars exploration of analogous sites. Method: We studied a partially subglacial hydrothermal area at the summit of the active Kverkfjöll volcano, Iceland. The heated ground has created a large ice-damned meltwater lake with shoreline hot springs, thermal streams, and mud pots of variable activity. We collected water and sediment samples aseptically across the breadth of features, including the lake (surface & depth). Samples were kept at -4°C. Environmental parameters were measured at each sample site. Sediment samples were split for mineralogical and organic analysis. Mineralogy was measured by X-ray Diffraction. Organic samples were freeze-dried and extracted with a Bligh & Dyer method (Bligh and Dyer 1959). Extracts were divided into hydrocarbons, neutral lipids, glycolipids, and phospholipid fatty acids (PLFA) with hexane, dichloromethane, acetone, and methanol. Gas Chromatography/Mass Spectrometry was used to analyze hydrocarbons and PLFA as fatty acid methyl esters. Results: Environmental: Fluids ranged from acidic to alkaline (pH 3-9), low to high temperature (8-87°C), and severely dysoxic to oxic (0.5-5 mg/L dissolved O). Mineralogy comprised a dioctahedral swelling clay, heulandite, and minor quartz, anatase, and pyrite. The assemblage suggests argillic-grade alteration at 100-140°C (Fulignati 2020), confirming that the glaciovolcanic conditions were within theoretical boundaries for life (<150°C (Merino et al. 2019)), and formed minerals capable of protecting organic matter (e.g., swelling clay). Lipids: PLFA are essential components of cell membranes and degrade rapidly upon cell death. PLFA profiles thus provide insight into the composition and distribution of the viable community. Results revealed a diversity of PLFA with low molecular weights and several bacterial-diagnostic structures, indicating an active prokaryote-dominated biosphere. Molecular patterns correlated (p<0.05) with pH, temperature, and oxygen, suggesting homeoviscous adaptations or community composition variations. In either case, microbes demonstrate adaptability to extreme conditions in glaciovolcanic settings. Hydrocarbons are inert and used as molecular fossils. We detected multiple patterns attributable to microbial biosynthesis, including abundant C17 (straight and branched) diagnostic of cyanobacteria; high concentrations of short-chain n-alkane/alkene doublets (<C22) with an even carbon preference (CPI<1) indicating diverse microbial input; and a narrow unresolved complex mixture with elution parameters characteristic of microbial heterotrophy (Finkel et al. 2023). The pattern of even-numbered alkane/alkene pairs has been scarcely reported and offers insight into rare hydrocarbon distributions. Interestingly, the hydrocarbon and PLFA patterns do not align. Thus, PLFA are not a significant source of hydrocarbons here and we suggest direct microbial synthesis dominates. Implications of this hypothesis will be discussed in the context of palaeobiological reconstruction. Conclusion: Our site provides an array of physicochemical niches for diverse life modes and a mineral assemblage amenable to organic preservation. Analogous sites on Mars should be explored, but more work is needed to understand preservation biases of hydrocarbon sources and the implications for interpretation.

Application of organic manure as a potential strategy to alleviate the limitation of microbial resources in soybean rhizospheric and bulk soils

The development and vigor of soil microorganisms in terrestrial ecosystems are frequently constrained by the limited availability of essential elements such as carbon (C), nitrogen (N), and phosphorus (P). In this study, we investigated the impact of long-term application of varying levels of organic manure, low (7.5 Mg ha−1 yr−1), moderate (15.0 Mg ha−1 yr−1), and high (22.5 Mg ha−1 yr−1), on the stoichiometry of enzymes and the structures of the microbial communities in soybean rhizospheric and bulk soils. The main goal of this research was to examine how soil microbial resource limitations in the rhizosphere respond to different long-term fertilization strategies. The soil enzymatic activities were quantified, and the structure of the microbial community was assessed by analyzing phospholipid fatty acid profiles. When compared to the bulk soil, the rhizospheric soil had significant increases in microbial biomass carbon (MBC), nitrogen (MBN), and phosphorus (MBP), with MBC increasing by 54.19 to 72.86%, MBN by 47.30 to 48.17%, and MBP by 17.37 to 208.47%. Compared with the unfertilized control (CK), the total microbial biomasses of the rhizospheric (increased by 22.80 to 90.82%) and bulk soils (increased by 10.57 to 60.54%) both exhibited increases with the application of organic manure, and the rhizospheric biomass was higher than that of bulk soil. Compared with bulk soil, the activities of C-, N- and P-acquiring enzymes of rhizospheric soil increased by 22.49, 14.88, and 29.45% under high levels of organic manure, respectively. Analyses of vector length, vector angle, and scatter plots revealed that both rhizospheric and bulk soils exhibited limitations in terms of both carbon (C) and phosphorus (P) availability. The results of partial least-squares path modelling indicated that the rhizospheric soil exhibited a more pronounced response to the rate of manure application than the bulk soil. The varying reactions of rhizospheric and bulk soils to the extended application of organic manure underscore the crucial function of the rhizosphere in mitigating limitations related to microbial resources, particularly in the context of different organic manure application rates.

Comparison of Soil Microbial Community between Managed and Natural Vegetation Restoration along a Climatic Gradient in Karst Regions

Managed and natural vegetation restorations are two vital measures of land restoration; however, their effects on soil microbial communities at a large scale are not clearly understood. Hence, changes in the microbial community composition after 15 years of vegetation restoration along a climatic gradient in the subtropical karst region of Southwest China were assessed based on phospholipid fatty acids (PLFAs) profiles. Managed (plantation forest) and natural (naturally recovered to shrubbery) vegetation restoration types were compared, with cropland and mature forest serving as controls. Soil microbial community abundance was significantly higher under the two vegetation restoration types than in the cropland; however, it was lower than in the mature forest. The abundance, composition, and structure of soil microbial communities did not differ significantly between plantation forest and shrubbery. Soil organic carbon or total nitrogen was the primary factor positively affecting soil microbial abundance, whereas the mean annual temperature (MAT) was recognized as the primary factor contributing to the variation in the soil microbial community structure. Moreover, temperature had opposite effects on different indicators of microbial community structure. That is, it positively and negatively affected the ratios of gram-positive to gram-negative bacterial PLFAs (GP:GN) and fungal to bacterial PLFAs (F:B), respectively. Our results show that both vegetation restoration types have the ability to improve soil productivity in karst areas. Furthermore, shifts in soil microbial community structure (GP:GN and F:B ratios) induced by warming are likely to lead to a higher proportion of labile carbon, which is sensitive to soil tillage. Hence, more attention should be paid to ecological restoration in warmer karst areas to alleviate the severe loss of soil carbon in croplands.

Influence of land use on soil microbial communities of sub Himalayas of India: insights from phospholipid fatty acid profiles, ribosomal intergenic spacer profiles, soil enzymes, and carbon pools

Influence of land use on soil microbial communities of sub Himalayas of India: insights from phospholipid fatty acid profiles, ribosomal intergenic spacer profiles, soil enzymes, and carbon pools

Effect of mixing intensity on volatile fatty acids production in sludge alkaline fermentation: Insights from dissolved organic matter characteristics and functional microorganisms

Alkaline fermentation for volatile fatty acids (VFAs) production has shown potential as a viable approach to treat sewage sludge. The hydrolysis and acidogenesis of sludge are greatly influenced by mixing. However, the effects of mixing intensity on VFAs production in sludge alkaline fermentation (SAF) remain poorly understood. This study investigated the impacts of mixing intensity (30, 90 and 150 rpm continuous mixing, and 150 rpm intermittent mixing) on VFAs production, dissolved organic matter (DOM) characteristics, phospholipid fatty acid profiles and microbial population distribution in SAF. Results showed that 150 rpm continuous and intermittent mixing enhanced the hydrolysis of sludge, while 150 rpm intermittent mixing resulted in the highest VFAs production (3886 ± 266.1 mg COD/L). Analysis of fluorescent and molecular characteristics of DOM revealed that 150 rpm intermittent mixing facilitated the conversion of released DOM, especially proteins-like substances, into VFAs. The abundance of unsaturated and branched fatty acids of microbes increased under 150 rpm intermittent mixing, which could aid in DOM degradation and VFAs production. Firmicutes and Tissierella were enriched at 150 rpm intermittent mixing, which favored the maximum VFAs yield. Moreover, Firmicutes were found to be the key functional microorganisms influencing the yield of VFAs during SAF. This study provides an understanding about the mixing intensity effects on VFAs production during SAF, which could be helpful to improve the yield of VFAs.

Mineral type and land-use intensity control composition and functions of microorganisms colonizing pristine minerals in grassland soils

Mineral surfaces in soil are an important interface for organic matter (OM) and nutrient cycling, with associated microorganisms contributing to the formation and turnover of mineral-associated OM (MAOM). However, the relevance of intrinsic (mineral type) versus extrinsic (land-use intensity) factors on the co-development of MAOM and microorganisms under natural conditions remains poorly understood. Mineral containers filled with mixtures of quartz-sand and pristine secondary minerals (goethite or illite) were exposed to 50 grassland topsoils of the Schwäbische Alb (Germany) along a land-use intensity gradient for five years. Mineral samples and soils were analyzed for organic carbon (OC) and nutrients (N and P), abundance and composition of major microbial groups based on phospholipid fatty acid profiles, as well as enzyme activities (β-glucosidase, β-xylosidase, N-acetylglucosaminidase, and acid phosphatase). Microorganisms colonized both mineral samples to the same extent, with goethite samples exhibiting greater MAOM accumulation and higher enzyme activities than illite samples. Both mineral samples differed from the overlying soils with greater relative abundances of fungi and Gram-negative bacteria and greater microbial acquisition of nutrients (N and P) relative to C as indicated by the stoichiometry of enzyme activities. Increasing land-use intensity was associated with decreasing C:N ratios and microbial abundances for goethite samples and increasing β-glucosidase activity for illite samples while the proportion of fungi was reduced in both mineral samples. We conclude that in the studied temperate grasslands the association of OM and microorganisms with secondary minerals is driven more by mineral type and reactivity than by differences in land-use intensity. The different minerals apparently formed distinct microhabitats with unique characteristics that differed in MAOM accumulation and microbial access to OC and nutrients, thus affecting microbial colonization and functionality.

Close coupling of plant functional types with soil microbial community composition drives soil carbon and nutrient cycling in tundra heath

AimsThis study aimed at elucidating divergent effects of two dominant plant functional types (PFTs) in tundra heath, dwarf shrubs and mosses, on soil microbial processes and soil carbon (C) and nutrient availability, and thereby to enhance our understanding of the complex interactions between PFTs, soil microbes and soil functioning.MethodsSamples of organic soil were collected under three dwarf shrub species (of distinct mycorrhizal association and life form) and three moss species in early and late growing season. We analysed soil C and nutrient pools, extracellular enzyme activities and phospholipid fatty acid profiles, together with a range of plant traits, soil and abiotic site characteristics.ResultsShrub soils were characterised by high microbial biomass C and phosphorus and phosphatase activity, which was linked with a fungal-dominated microbial community, while moss soils were characterised by high soil nitrogen availability, peptidase and peroxidase activity associated with a bacterial-dominated microbial community. The variation in soil microbial community structure was explained by mycorrhizal association, root morphology, litter and soil organic matter quality and soil pH-value. Furthermore, we found that the seasonal variation in microbial biomass and enzyme activities over the growing season, likely driven by plant belowground C allocation, was most pronounced under the tallest shrub Betula nana.ConclusionOur study demonstrates a close coupling of PFTs with soil microbial communities, microbial decomposition processes and soil nutrient availability in tundra heath, which suggests potential strong impacts of global change-induced shifts in plant community composition on carbon and nutrient cycling in high-latitude ecosystems.

The Effect of Plant Diversity and Soil Properties on Soil Microbial Biomass and Activity in a Novel Ecosystem

Plant–microbial relations have not yet been fully disclosed in natural or seminatural ecosystems, nor in novel ecosystems developing spontaneously on post-coal mine heaps. The aim of this study was to determine which factor, biotic (plant taxonomic diversity vs. plant functional diversity) or abiotic (physicochemical substrate parameters), affects the biomass of soil microbial communities the most, as well as soil in situ respiration in novel ecosystems. The study was carried out on unreclaimed plots selected according to four different combinations of taxonomic and functional plant diversity. Additionally, plots on a reclaimed heap served as a comparison between the two management types. The biomass of several soil microbial groups was analysed using phospholipid fatty acids profiles. We detected that soil microbial biomass was more impacted by abiotic parameters (explaining 23% of variance) than plant diversity (explaining 12% of variance). Particularly, we observed that substrate pH was the most important factor shaping microbial community biomass, as shown in the RDA analysis. The highest microbial biomass was found in plots with low taxonomic and functional diversity. This finding can be explained by the fact that these plots represented a more advanced phase of vegetation development in the early stages of plant succession.

Gastrointestinal structure and function of preweaning dairy calves fed a whole milk powder or a milk replacer high in fat

The composition of milk replacer (MR) for calves greatly differs from that of bovine whole milk, which may affect gastrointestinal development of young calves. In this light, the objective of the current study was to compare gastrointestinal tract structure and function in response to feeding liquid diets having a same macronutrient profile (e.g., fat, lactose, protein) in calves in the first month of life. Eighteen male Holstein calves (46.6 ± 5.12 kg; 1.4 ± 0.50 d of age at arrival; mean ± standard deviation) were housed individually. Upon arrival, calves were blocked based on age and arrival day, and, within a block, calves were randomly assigned to either a whole milk powder (WP; 26% fat, DM basis, n = 9) or a MR high in fat (25% fat, n = 9) fed 3.0 L 3 times daily (9 L total per day) at 135 g/L through teat buckets. On d 21, gut permeability was assessed with indigestible permeability markers [chromium (Cr)-EDTA, lactulose, and d-mannitol]. On d 32 after arrival, calves were slaughtered. The weight of the total forestomach without contents was greater in WP-fed calves. Furthermore, duodenum and ileum weights were similar between treatment groups, but jejunum and total small intestine weights were greater in WP-fed calves. The surface area of the duodenum and ileum did not differ between treatment groups, but the surface area of the proximal jejunum was greater in calves fed WP. Urinary lactulose and Cr-EDTA recoveries were greater in calves fed WP in the first 6 h post marker administration. Tight junction protein gene expression in the proximal jejunum or ileum did not differ between treatments. The free fatty acid and phospholipid fatty acid profiles in the proximal jejunum and ileum differed between treatments and generally reflected the fatty acid profile of each liquid diet. Feeding WP or MR altered gut permeability and fatty acid composition of the gastrointestinal tract and further investigation are needed to understand the biological relevance of the observed differences.

Phospholipid Fatty Acid Profiles of Plasma and Erythrocyte Membranes in Dogs Fed with Commercial Granulated Food

Abstract Intake of long-chain n-3 polyunsaturated fatty acids (PUFA) benefits human and animal health. Our study aimed to analyze the long-chain n-3 PUFA content of two types of food and their effect on plasma and erythrocyte phospholipids of Belgian Shepherd dogs. A total of 10 dogs were fed commercial granulated food (Food 1), and another 10 were provided commercial Premium granulated food of high quality (Food 2). All the analyses were performed using gas-liquid chromatography. Our results showed that Food 1 contained more n-3 PUFA than Food 2, which was reflected in higher n-3 PUFA in plasma and erythrocyte phospholipids. Because long-chain n-3 PUFA in phospholipids are precursors for antioxidative molecules, further studies should investigate the effects of the analyzed commercial granulated food rich in n-3 on oxidative stress parameters in dogs.

Thermal modulation of mitochondrial function is affected by environmental nickel in rainbow trout (Oncorhynchus mykiss)

In this study, we investigated the combined effects of temperature and nickel (Ni) contamination on liver mitochondria electron transport system (ETS) enzymes, citrate synthase (CS), phospholipid fatty acid composition and lipid peroxidation in rainbow trout (Oncorhynchus mykiss). Juvenile trout were acclimated for two weeks to two different temperatures (5˚C and 15˚C) and exposed to nickel (Ni; 520 μg/L) for three weeks. Using ratios of ETS enzymes and CS activities, our data suggest that Ni and an elevated temperature acted synergistically to induce a higher capacity for reduction status of the ETS. The response of phospholipid fatty acid profiles to thermal variation was also altered under nickel exposure. In control conditions, the proportion of saturated fatty acids (SFA) was higher at 15˚C than at 5˚C, while the opposite was observed for monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA). However, in nickel contaminated fish, the proportion of SFA was higher at 5˚C than at 15˚C, while PUFA and MUFA followed the opposite direction. A higher PUFA ratio is associated with higher vulnerability to lipid peroxidation. Thiobarbituric Acid Reactive Substances (TBARS) content was higher when the PUFA were in higher proportions, except for Ni-exposed, warm-acclimated fish, in which we reported the lowest level of TBARS but the highest proportion of PUFA. We suspect that the interaction of nickel and temperature on lipid peroxidation is due to their synergistic effects on aerobic energy metabolism, as supported by the decrease in the activity of complex IV of the ETS enzyme activity in those fish, or on antioxidant enzymes and pathways. Overall, our study demonstrates that Ni exposure in heat-challenged fish can lead to the remodelling of the mitochondrial phenotype and potentially stimulate alternative antioxidant mechanisms.

Plasma Amino Acids in Early Pregnancy and Midpregnancy and Their Interplay With Phospholipid Fatty Acids in Association With the Risk of Gestational Diabetes Mellitus: Results From a Longitudinal Prospective Cohort.

We prospectively evaluated plasma amino acids (AAs) in early pregnancy and midpregnancy and their interplay with phospholipid fatty acids (FAs) in association with gestational diabetes mellitus (GDM) risk. From a longitudinal pregnancy cohort of 2,802 individuals, concentrations of 24 plasma AAs at 10-14 and 15-26 gestational weeks (GW) were assessed among 107 GDM case subjects and 214 non-GDM control subjects. We estimated adjusted odds ratios (OR) and 95% CI for the associations of plasma AAs and the joint associations of plasma AAs and phospholipid FAs with GDM risk, adjusting for risk factors including age, prepregnancy BMI, and family history of diabetes. Glycine at 10-14 GW was inversely associated with GDM (adjusted OR [95% CI] per SD increment: 0.55 [0.39-0.79]). Alanine, aspartic acid, and glutamic acid at 10-14 GW were positively associated with GDM (1.43 [1.08-1.88], 1.41 [1.11-1.80], and 1.39 [0.98-1.98]). At 15-26 GW, findings for glycine, alanine, aspartic acid, and the glutamine-to-glutamic acid ratio were consistent with the directions observed at 10-14 GW. Isoleucine, phenylalanine, and tyrosine were positively associated with GDM (1.64 [1.19-2.27], 1.15 [0.87-1.53], and 1.56 [1.16-2.09]). All P values for linear trend were <0.05. Several AAs and phospholipid FAs were significantly and jointly associated with GDM. For instance, the lowest risk was observed among women with higher glycine and lower even-chain saturated FAs at 10-14 GW (adjusted OR [95% CI] 0.15 [0.06, 0.37]). Plasma AAs may be implicated in GDM development starting in early pregnancy. Associations of AAs with GDM may be enhanced in the copresence of phospholipid FA profile.

Changes in vineyard soil parameters after repeated application of organic-inorganic amendments based on spent mushroom substrate

The changes of physicochemical and biochemical parameters of a silty loam (S1) and sandy loam (S2) vineyard soils added with spent mushroom substrate (SMS) or SMS composted with ophite (OF) as rock dust (SMS + OF) were studied. Two doses of SMS or SMS + OF (25 and 100 Mg ha−1) were applied for two consecutive years (2020–2021) and changes of soil physicochemical parameters, and dehydrogenase activity (DHA), respiration (RES), microbial biomass (BIO), and the phospholipid fatty acids (PLFAs) profile were assayed on a temporal basis. The results showed an increase in soil organic carbon (OC) content, total and mineralised N, P, and K, especially when the highest SMS dose was applied to soils. Repeated application caused OC content over time up to 2.3 times higher than initial content in the silty loam soil. This increase was not observed in sandy soil, possibly due to a higher bioavailability of OC, as indicated by the evolution of extractable humic acid/fulvic acid pools. In both soils, all biochemical parameters increased after amendment, being favoured both by the OC and by the presence of OF. Significant positive correlations were found between DHA, RES and BIO, and OC content especially in the first part and then levelled off after the second dose application. Total bacterial or fungal PLFAs patterns reflected the variation of BIO by SMS application. The higher growth of fungi vs. bacterial community in amended soils was recorded after the first SMS application, although the opposite effect occurred after the second application, with similar results in both soils. The findings indicate that the application of SMS or SMS + OF in vineyard soils could be an appropriate agronomic management practice for maintaining soil sustainability, although doses and application times of these amendments should first be evaluated depending on soil texture.

Biogeochemical properties of blue carbon sediments influence the distribution and monomer composition of bacterial polyhydroxyalkanoates (PHA)

Coastal wetlands are highly efficient ‘blue carbon’ sinks which contribute to mitigating climate change through the long-term removal of atmospheric CO2 and capture of carbon (C). Microorganisms are integral to C sequestration in blue carbon sediments and face a myriad of natural and anthropogenic pressures yet their adaptive responses are poorly understood. One such response in bacteria is the alteration of biomass lipids, specifically through the accumulation of polyhydroxyalkanoates (PHAs) and alteration of membrane phospholipid fatty acids (PLFA). PHAs are highly reduced bacterial storage polymers that increase bacterial fitness in changing environments. In this study, we investigated the distribution of microbial PHA, PLFA profiles, community structure and response to changes in sediment geochemistry along an elevation gradient from intertidal to vegetated supratidal sediments. We found highest PHA accumulation, monomer diversity and expression of lipid stress indices in elevated and vegetated sediments where C, nitrogen (N), PAH and heavy metals increased, and pH was significantly lower. This was accompanied by a reduction in bacterial diversity and a shift to higher abundances of microbial community members favouring complex C degradation. Results presented here describe a connection between bacterial PHA accumulation, membrane lipid adaptation, microbial community composition and polluted C rich sediments.Graphical Geochemical, microbiological and polyhydroxyalkanoate (PHA) gradient in a blue carbon zone.

Sediment microbial community structure, enzymatic activities and functional gene abundance in the coastal hypersaline habitats

Salt marsh vegetation, mudflat and salt production are common features in worldwide coastal areas; however, their influence on microbial community composition and structure has been poorly studied and rarely compared. In the present study, microbial community composition (phospholipid fatty acid (PLFA) profiling and 16S rRNA gene sequencing (bacterial and archaeal)) and structure, enzymatic activities and abundance of functional genes in the sediments of salt ponds (crystallizer, condenser and reservoir), mudflat and vegetated mudflat were determined. Enzyme activities (β-glucosidase, urease and alkaline phosphatase) were considerably decreased in saltpan sediments because of elevated salinity while sediment of vegetated mudflat sediments showed the highest enzyme activities. Concentrations of total microbial biomarker PLFAs (total bacterial, Gram-positive, Gram-negative, fungal and actinomycetes) were the highest in vegetated mudflat sediments and the lowest in crystallizer sediments. Nonmetric-multidimensional scaling (NMDS) analysis of PLFA data revealed that the microbial community of crystallizer, mudflat and vegetated mudflat was significantly different from each other as well as different from condenser and reservoir. The most predominant phyla within the classified bacterial fractions were Proteobacteria followed by Firmicutes, Bacteroidetes and Planctomycetes, while Euryarchaeota and Crenarchaeota phyla dominated the classified archaeal fraction. Cyanobacterial genotypes were the most dominant in the condenser. Mudflat and vegetated mudflat supported a greater abundance of Bacteroidetes and Actinobacteria, respectively. The results of the present study suggest that salt ponds had significantly decreased the microbial and enzyme activities in comparison to mudflat and vegetated mudflat sediments due to very high salinity, ionic concentrations and devoid of vegetation. The present study expands our understanding of microbial resource utilization and adaptations of microorganisms in a hypersaline environment.