Neutral Lipid Fatty Acid Research Articles

Comparison of biochemical and microscopic methods for quantification of arbuscular mycorrhizal fungi in soil and roots

Arbuscular mycorrhizal fungi (AMF) are well-known plant symbionts which provide enhanced phosphorus uptake as well as other benefits to their host plants. Quantification of mycorrhizal density and root colonization has traditionally been performed by root staining and microscopic examination methods, which are time-consuming, laborious, and difficult to reproduce between laboratories. A number of biochemical markers for estimating mycorrhizal hyphae and spores have been published. In this study we grew maize plants in three different soils in a replicated greenhouse experiment and compared the results from two microscopic methods, spore density and root colonization, to the results from three lipid biomarker methods: neutral lipid fatty acid, phospholipid fatty acid, and ester-linked fatty acid analysis. Ester-linked fatty acid analysis gave consistent results for both spore density and root colonization, but neutral lipid fatty acid analysis had the highest correlation to AMF spore counts. Phospholipid fatty acid analysis was not correlated to spore density and did not reproducibly correlate to root colonization.

The Role of Storage Lipids in the Relation between Fecundity, Locomotor Activity, and Lifespan of Drosophila melanogaster Longevity-Selected and Control Lines.

The contribution of insect fat body to multiple processes, such as development, metamorphosis, activity, and reproduction results in trade-offs between life history traits. In the present study, age-induced modulation of storage lipid composition in Drosophila melanogaster longevity-selected (L) and non-selected control (C) lines was studied and the correlation between total body fat mass and lifespan assessed. The trade-offs between fecundity, locomotor activity, and lifespan were re-evaluated from a lipid-related metabolic perspective. Fewer storage lipids in the L lines compared to the C lines supports the impact of body fat mass on extended lifespan. The higher rate of fecundity and locomotor activity in the L lines may increase the lipid metabolism and enhance the lipolysis of storage lipids, reducing fat reserves. The correlation between neutral lipid fatty acids and fecundity, as well as locomotor activity, varied across age groups and between the L and C lines. The fatty acids that correlated with egg production were different from the fatty acids that correlated with locomotor activity. The present study suggests that fecundity and locomotor activity may positively affect the lifespan of D. melanogaster through the inhibition of fat accumulation.

Fatty acid composition in Mytilus galloprovincialis organs: trophic interactions, sexual differences and differential anatomical distribution

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 528:221-234 (2015) - DOI: https://doi.org/10.3354/meps11280 Fatty acid composition in Mytilus galloprovincialis organs: trophic interactions, sexual differences and differential anatomical distribution María-José Fernández-Reiriz*, José Luis Garrido, Jade Irisarri Consejo Superior de Investigaciones Científicas (CSIC), Instituto de Investigaciones Marinas (IIM), C/Eduardo Cabello 6, 36208 Vigo, Spain *Corresponding author: mjreiriz@iim.csic.es ABSTRACT: The fatty acid (FA) profiles in neutral lipids (NLs) and polar lipids (PLs) of the gills, digestive gland and mantle of female and male mussels Mytilus galloprovincialis (cultured in Ría de Arousa, Galicia, NW Spain, and studied during an annual seasonal cycle) reflected dietary, sexual and functional differences. Seasonal differences arose from variations in the trophic environment, with diatom FA biomarkers dominating during the spring bloom, biomarkers from dinoflagellate-rich diets dominating during winter mixing, and a combination of both sources apparent during the summer and autumn transitory periods. The influence of diet was more pronounced in the NL (energetic reserves) than in the PL (structural membrane components) FA signatures of all organs, although dietary changes were mirrored more clearly in the digestive gland. Differences between males and females were restricted to the mantle and probably resulted from gonadal ripeness during spring. The NL and PL FA profile of the mantle was characterized by the abundance of 14:0, 16:0 and 16:1n-7 in females and predominance of 18:0, 18:3n-3 and 22:6n-3 in males, suggesting that each gender has distinct energetic and structural requirements during gametogenesis. Lipids containing alkenyl ethers or non-methylene interrupted (NMI) FAs were mostly found in the PLs of the gills and the mantle, supporting their role as structural and functional components in the membranes of organs directly exposed to physicochemical fluctuations. Competition between NMI and polyunsaturated fatty acids (PUFAs) was only evident in the mantle, suggesting that deficiencies in PUFAs might provoke de novo biosynthesis of NMI to satisfy reproductive demands. KEY WORDS: Mussels · Neutral and polar lipids · Non-methylene interrupted fatty acids · Biomarkers · Sexual variation · Bivalve organs Full text in pdf format Supplementary material PreviousNextCite this article as: Fernández-Reiriz MJ, Garrido JL, Irisarri J (2015) Fatty acid composition in Mytilus galloprovincialis organs: trophic interactions, sexual differences and differential anatomical distribution. Mar Ecol Prog Ser 528:221-234. https://doi.org/10.3354/meps11280 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 528. Online publication date: May 28, 2015 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2015 Inter-Research.

Impact of tropical lowland rainforest conversion into rubber and oil palm plantations on soil microbial communities

Focusing on Sumatra, a hotspot of tropical lowland rainforest transformation, we investigated effects of the con- version of rainforests into rubber agroforests (Bjungle rubber^), intensive rubber, and oil palm plantations on the communities of litter and soil microorganisms and identified factors responsible for these changes. Litter basal respiration, microbial biomass, total bacterial phospholipid fatty acids (PLFAs), and fungal PLFAs did not vary significantly with rainforest conversion. In litter of converted ecosystems, the concentration of certain PLFAs including the Gram-negative bacteria marker PLFA cy17:0 and the Gram-positive bacteria marker PLFA i17:0 was reduced as compared to rainforest, whereas the concentration of the arbuscular mycorrhizal fungi (AMF) marker neutral lipid fatty acid (NLFA) 16:1ω5c in- creased. As indicated by redundancy analysis, litter pH and carbon concentration explained most of the variation in litter microbial community composition. In soil, microbial biomass did not vary significantly with rainforest conversion, whereas basal respiration declined. Total PLFAs and especially that of Gram-negative bacteria decreased, whereas PLFA i17:0 in- creased with rainforest conversion. The concentration of fun- gal PLFAs increased with rainforest conversion, whereas NLFA 16:1ω5c did not change significantly. Redundancy analysis indicated that soil pH explained most of the variation in soil microbial community composition. Overall, the data suggest that conversion of rainforests into production systems results in more pronounced changes in microbial community composition in soil as compared to litter. In particular, the response of fungi and bacteria was more pronounced in soil, while the response of AMF was more pronounced in litter. Notably, only certain bacterial markers but not those of saprotrophic fungi and AMF were detrimentally affected by rainforest conversion.

Dietary Flax Oil Enriches Adipose Tissue Phospholipids in Long Chain n‐3 PUFA and Reduces Adiposity

Consumption of diets enriched in long‐chain omega‐3 polyunsaturated fatty acids (LC n‐3 PUFA) has been associated with reduced adiposity and metabolic benefits in humans and animals, including poultry. Avians express unique elongase enzymes that, relative to humans, enhance their capacity to produce eicosapentaenoic acid (EPA, 20:5, n‐3) and docosahexaenoic acid (DHA, 22:6, n‐3) from alpha‐linolenic acid (ALA; 18:3, n‐3). We tested the hypothesis that enriching adipose tissue in ALA would reduce adiposity in broiler chickens by activating lipid‐responsive nuclear receptors and upregulating expression of genes involved in fatty acid oxidation, comparable to what we have previously found for fasting (Ji et al., 2012). Cobb 500 broiler chicks were fed isocaloric diets containing either 8% flaxseed oil (flax) or 8% lard from hatch to 21 days of age (DS1), or from 21‐42 days of age (DS2). Adipose neutral lipid fatty acid profiles reflected the dietary fat composition. Both EPA and DHA were undetectable in adipose phospholipids (PL) from the lard group but were present in birds consuming flax, while arachidonic acid was increased in PL of the lard group. In both DS1 and DS2, flax diets significantly (p<0.05) reduced adiposity and abdominal adipose weight, with no effect on body weight. Plasma non‐esterified fatty acid (NEFA) levels were significantly lower in flax vs. lard birds in both studies (p=0.0062, DS1 and p=0.014, DS2). Despite the significant reduction in adiposity, we did not find evidence for upregulation of genes involved in fatty acid oxidation based on QPCR of abdominal adipose tissue. In conclusion, these studies demonstrate that dietary enrichment in ALA reduces adiposity, but the mechanisms remain to be determined.

Depth, soil type, water table, and site effects on microbial community composition in sediments of pesticide-contaminated aquifer

Microbial community compositions in pesticide-contaminated aquifers have not been studied, although such information is important for remediation and maintaining freshwater sources clean under changing climate. Therefore, phospholipid (PLFAs), glycolipid (GLFAs), and neutral lipid (NLFAs) fatty acids were determined from sand and clay sediments at depths of 0.3-24.8m, all contaminated with triazines and dichlobenil/2,6-dichlorobenzamide. The portion of fungi and Gram-negative bacteria at 0.3m was greater than at 0.8m, where the percentage of Gram-positive bacteria, actinobacteria, and sulfate-reducing bacteria (SRB) increased. In deeper sediments, microbial biomass, activity, and diversity decreased. Clay sediments seemed to serve as a reservoir for slow pesticide elution to groundwater, and their biomarker portion for all bacteria except actinobacteria was greater than in sand sediments. The slow pesticide dissipation seemed to occur in the main groundwater flow zone, resulting in nitrogen release simultaneously with organic matter elution from gardening and bank filtration. As a result, microbial biomass, activity, and diversity were increased. This shift in conditions towards that in surface soil may be appropriate for enhanced natural attenuation of pesticides in groundwater sources.

Crop rotation and seasonal effects on fatty acid profiles of neutral and phospholipids extracted from no‐till agricultural soils

AbstractAnalysis of phospholipids (PLFA) and neutral lipids fatty acids (NLFA) was used to characterize no‐till productive agricultural soils associated with different crop rotation levels, replicated across a 400 km transect in the Argentinean pampas, during two sampling seasons, summer and winter. High rotation (HR) management consisted in maize–wheat–soybean intense rotation including cover crops. Low rotation (LR) management trend to soybean monocultures. Soils from nearby natural environments (NEs) were used as references. Fatty acids concentration in soils (nmol/g) decreased c.a. 50% from summer to winter differentially according to soil treatment being the smallest decrease in HR management 35%. Both PLFA and NLFA profiles showed strong potential to discriminate between different land uses. In winter samples, some rare or unknown fatty acids were relevant for the discrimination of agricultural practices while NLFA 20:0 appears to be a good marker of HR soils despite season or location. The PLFA‐based taxonomic biomarkers for total bacteria, Gram‐negative bacteria and arbuscular mycorrhiza showed a significant trend NE>HR>LR in the winter sampling. HR management was also characterized by high levels of NLFA in winter samples as if high crop rotation improves lipids reserves in soil during winter more than in monocropping soil management. In conclusion, PLFA and particularly NLFA profiles appear to provide useful and complementary information to obtain a footprint of different soil use and managements, improving soil biochemistry characterization tools.

Long-term fertilizer application effects on the soil, root arbuscular mycorrhizal fungi and community composition in rotation agriculture

Arbuscular mycorrhizal fungi (AMF) play key roles in plant growth, ecosystem sustainability and stability. However, it is still unclear how the soil, root AMF growth and community composition are affected by fertilizer application in subtropical wheat–rice rotation agro-ecosystems. We investigated the impact of different organic and/or inorganic fertilizers on AMF growth and community composition in a long-term experiment field in Zhejiang Province, east China. AMF biomass was determined using 16:1ω5 phospholipid fatty acids (PLFAs) and neutral lipid fatty acids (NLFAs) content. Soil and root AMF community compositions were determined by DGGE analysis, cloning, sequencing and phylogenetic analyses. The root colonization rate was not significantly affected by different fertilizer regimes. Manure amendment significantly enhanced both AMF hyphal (i.e., 16:1ω5 PLFA) and spore (i.e., 16:1ω5 NLFA) biomass content, while inorganic fertilizer only increased the AMF spore biomass. A total of 10 and 11 Glomeromycota phylotypes were detected in soil and root samples, respectively. Glomus was the dominant genus in both soil and root samples, while Acaulospora genus occurred in roots only. Although the different fertilizers altered soil AMF communities, the root AMF community structure was not significantly altered. Soil pH (F=5.695, P<0.01) and available K (F=4.888, P<0.01) contributed to both soil and root AMF community composition, while the C/P ratio (F=3.893, P<0.01) only contributed to soil AMF community. The data suggests that high soil organic C content benefits AMF growth, while soil pH and available K concentration strongly influence AMF community. The root AMF community was much more resilient to the changes caused by long-term fertilizer application than the soil community.

Exploring the transfer of recent plant photosynthates to soil microbes: mycorrhizal pathway vs direct root exudation.

Plants rapidly release photoassimilated carbon (C) to the soil via direct root exudation and associated mycorrhizal fungi, with both pathways promoting plant nutrient availability. This study aimed to explore these pathways from the root's vascular bundle to soil microbial communities.Using nanoscale secondary ion mass spectrometry (NanoSIMS) imaging and 13C-phospho- and neutral lipid fatty acids, we traced in-situ flows of recently photoassimilated C of 13CO2-exposed wheat (Triticum aestivum) through arbuscular mycorrhiza (AM) into root- and hyphae-associated soil microbial communities.Intraradical hyphae of AM fungi were significantly 13C-enriched compared to other root-cortex areas after 8 h of labelling. Immature fine root areas close to the root tip, where AM features were absent, showed signs of passive C loss and co-location of photoassimilates with nitrogen taken up from the soil solution. A significant and exclusively fresh proportion of 13C-photosynthates was delivered through the AM pathway and was utilised by different microbial groups compared to C directly released by roots.Our results indicate that a major release of recent photosynthates into soil leave plant roots via AM intraradical hyphae already upstream of passive root exudations. AM fungi may act as a rapid hub for translocating fresh plant C to soil microbes.

Changes in Soil Ergosterol Content, Glomalin-Related Soil Protein, and Phospholipid Fatty Acid Profile as Affected by Long-Term Organic and Chemical Fertilization Practices in Mediterranean Turkey

The present study examines the effects of different fertilization treatments (chemical fertilization, farmyard manure, plant compost, and mycorrhiza-inoculated compost) on the soil fungi under a crop rotation of wheat (Triticum aestivum L.) and corn (Zea mays L.) in a long-term field experiment established in Mediterranean Turkey in 1996. Soil samples were collected in May, August, and October 2009. Soil pH, organic carbon, plant-available nitrogen and phosphorus, mycorrhizal colonization, and a series of biochemical markers (phospholipid and neutral lipid fatty acid [PLFA and NLFA] profiles, soil ergosterol content, and glomalin related soil protein [GRSP] as indicators of abundance of bacteria, saprotrophic, and arbuscular mycorrhizal [AM] fungi) were assessed. No significant difference was observed in soil organic C and plant available N in relation to long-term fertilization treatments, but plant available P in soil changed significantly in relation to the fertilization treatment used and the sampling season (between 11.5–33.8 mg · kg−1 in spring, 10.4–28.6 mg · kg−1 in summer, and 10.5–33.2 mg · kg−1 in autumn). Mycorrhizal colonization patterns were similar for both plants. However, mycorrhiza-inoculated compost treatment exhibited higher root colonization (77.3%) over control (16.3%), chemical fertilization (10.0%), farmyard manure (19.3%), and plant compost (20.0%). No statistically significant change was observed in ergosterol content. The effect of long-term organic treatments on soil PLFA structure was statistically prominent; whereas seasonality only affected bacterial PLFAs. Organic fertilization increased GRSP (mean annual ranging from 0.91 to 2.46 mg · g−1 total GRSP) but long-term annual mycorrhizal inoculation had no significant effect on the soil GRSP pool.

Influence of hormonal induction and broodstock feeding on longfin yellowtailSeriola rivolianamaturation, spawning quality and egg biochemical composition

To optimize broodstock management for Seriola rivoliana, a survey over 5 years was performed to evaluate the effects of successive hormonal inductions with GnRHa or dietary regime on spawning quality. Running males and females with an oocyte diameter > 500 μm were injected with GnRHa. The spawning quality was compared among consecutive years and different moments along the spawning season. Besides, three different feeding regimes were tested. Spawning quality parameters were not significantly affected by time along the spawning season, whereas they were clearly influenced by diet. Particularly, broodfish fed the mackerel regime (M) showed a significantly higher number of eggs than other treatments. Besides, dietary protein content significantly improved broodstock fecundity of S. rivoliana. Moreover, hatching rates were also higher in broodfish fed mackerel and the dietary docosahexaenoic acid (DHA) levels significantly increased this parameter. Despite polar lipids were not significantly affected, neutral lipids fatty acid composition of S. rivoliana eggs showed higher 18:2n-6 in eggs, whereas ARA content was not affected. The results of this study denoted the high fecundity and good spawning quality of S. rivoliana broodfish and suggested the importance of high protein, energy and DHA levels in broodstock diets.

Fatty acid profile and cholesterol and retinol contents in different locations of Celta pig breed

The fatty acid profile (total, neutral and polar lipids) and cholesterol and retinol contents of the intramuscular -Longissimus dorsi (LD) and Psoas major (PM)-, adipose -rump, covering Biceps femoris muscle, ventral and dorsal-, perirenal and hepatic fat of the Celta pig breed (Galicia, northwest Spain) were evaluated. Oleic acid was the most abundant fatty acid, except in the polar lipids of the intramuscular fat, where the most abundant fatty acid was linoleic acid. The fatty acid composition of total and neutral lipids was influenced more by the location than the fatty acids of polar lipids. There were some differences only in minor fatty acids of intramuscular and subcutaneous fat between castrated females and castrated males. The fatty acids of neutral lipids were also more influenced by sex than the fatty acids of polar lipids. The cholesterol and retinol contents showed no significant differences by sex. The LD muscle showed a higher content of intramuscular fat than the PM muscle. The greatest cholesterol values were described in the liver. Subcutaneous locations showed higher cholesterol levels than muscles.

Comparison of fertility and seasonal effects on grassland microbial communities

The activity of saprotrophic fungi and bacteria, and the balance between them, can affect decomposition. Arbuscular mycorrhizal (AM) fungi are also important for the nutrient and energy transfer in soil. Microbial community composition and activity are believed to have seasonal patterns, and are known to be highly influenced by environmental factors such as pH and nutrient conditions. To evaluate the importance of season for the variation in microbial decomposer community in a context of well-known environmental factor variation, we studied microbial growth, biomass and community structure along a fertility gradient (pH 5.9–8.1; NH4-N 3–19 μg g−1 soil, f.w.) in a sandy grassland during one year. The microbial community structure (phospholipid fatty acid (PLFA) composition) and biomass (PLFA and neutral lipid fatty acid (NLFA) signatures) as well as fungal (acetate incorporation in ergosterol) and bacterial (leucine incorporation) growth rates were investigated at eight seasonal time points during one year. The environmental factors pH and NH4 concentrations explained a larger share of the variation in the microbial community structure. Together they explained 37% of the variation, while season (proxied by temperature) only explained 6% of the variation in PLFA composition. Bacterial and fungal biomass were both highest in early spring, while AM fungal biomass peaked in early summer. Bacterial growth rate, on the other hand, was highest during the autumn, while fungal growth rate showed no clear seasonal pattern. In conclusion, the influence of seasonal variation on microbial communities proved to be relatively small compared to that which could be assigned to pH and NH4 in the studied ranges.

Tissue-Specific Fatty Acids Response to Different Diets in Common Carp (Cyprinus carpio L.)

Fish depend on dietary fatty acids (FA) to support their physiological condition and health. Exploring the FA distribution in common carp (Cyprinus carpio), one of the world's most consumed freshwater fish, is important to understand how and where FA of different sources are allocated. We investigated diet effects on the composition of polar and neutral lipid fatty acids (PLFA and NLFA, respectively) in eight different tissues (dorsal and ventral muscle, heart, kidney, intestine, eyes, liver and adipose tissue) of common carp. Two-year old carp were exposed to three diet sources (i.e., zooplankton, zooplankton plus supplementary feeds containing vegetable, VO, or fish oil, FO) with different FA composition. The PLFA and NLFA response was clearly tissue-specific after 210 days of feeding on different diets. PLFA were generally rich in omega-3 polyunsaturated FA and only marginally influenced by dietary FA, whereas the NLFA composition strongly reflected dietary FA profiles. However, the NLFA composition in carp tissues varied considerably at low NLFA mass ratios, suggesting that carp is able to regulate the NLFA composition and thus FA quality in its tissues when NLFA contents are low. Finally, this study shows that FO were 3X more retained than VO as NLFA particularly in muscle tissues, indicating that higher nutritional quality feeds are selectively allocated into tissues and thus available for human consumption.

Collembola feeding habits and niche specialization in agricultural grasslands of different composition

The introduction of white clover in grassland is a common practice to improve the quality of the pasture and to limit the use of industrial sources of inorganic fertilizer N inputs. However, little is known about the extent to which the introduction of different crop compositions affects soil quality in general, and soil biota in particular. Recent studies have shown that epedaphic and euedaphic Collembola can have distinct differences in feeding strategy that suggests trophic niche differentiation according to soil habitat. Combining fatty acid (FA) biomarkers with the carbon isotopic ratios technique, we investigated belowground trophic interactions. We compared the FA composition of the three most predominant groups of Collembola (Isotoma spp., Lepidocyrtus cyaneus and Poduromorpha) and bulk soil in white clover-only, a grass-clover mixture, and grass-only plots. Differences between FA-δ13C of Collembola groups and the FA-δ13C signatures of potential food sources (plant material and soil microorganisms) were calculated to explore trophic links in the three cropping combinations. Collembola showed difference in FA compositions between groups. We observed a lower amount of neutral lipid fatty acids (NLFAs) in Isotoma spp. compared to L. cyaneus. Poduromorpha showed a higher relative percentage of the NLFAs 16:1ω7 and 20:4 compared to L. cyaneus, and of 18:3 compared to Isotoma spp. The NLFA oleic/linoleic ratio (18:1ω9/18:2ω6,9) ratio was higher in Poduromorpha compared to L. cyaneus in all the treatments. Soil FA analysis highlighted a larger fungal/bacterial ratio in grass compared to clover plots, while in Collembola no differences in the FA pattern were detected in relation to the treatments. Nevertheless, results of δ13C fractionation in Collembola disclosed differences in the food sources used depending on the crop composition. Apparently, Isotoma spp. and L. cyaneus fed on clover-related diet in clover plots and more on grass-related diet in mixture treatments while Poduromorpha fed more on a plant-related diet, such as leaf litter, in the mixture treatment. Our results suggest differentiation in Collembola feeding strategy and in the diet in relation to food availability and palatability.

Changes in microbial communities and carbohydrate profiles induced by the mycorrhizal fungus (Glomus intraradices) in rhizosphere of olive trees (Olea europaea L.)

The influence of inoculation of olive trees with arbuscular mycorrhizal (AM) fungi, Glomus (G) intraradices, on microbial communities and sugar concentrations, were examined in rhizosphere of olive trees (Olea europaea L.). Analyses of phospholipid and neutral lipid fatty acids (PLFA and NLFA, respectively) were then used to detect changes in microbial community structure in response to inoculation of plantlets with G. intraradices.Microscopic observations studies revealed that the extraradical mycelium of the fungus showed formation of branched absorbing structures (BAS) in rhizosphere of olive tree. Root colonization with the AM fungi G. intraradices induced significant changes in the bacterial community structure of olive tree rhizosphere compared to non-mycorrhizal plants. The largest proportional increase was found for the fatty acid 10Me18:0, which indicated an increase in the number of actinomycetes in mycorrhizal rhizosphere soil, whereas the PLFAs i15:0, a15:0, i16:0, 16:1ω7 and cy17:0 which were used as indicators of bacteria decreased in mycorrhizal treatment compared to non-mycorrhizal control treatment. A highest concentration of glucose and trehalose and a lowest concentration of fructose, galactose, sucrose, raffinose and mannitol were detected in mycorrhizal rhizosphere soil. This mycorrhizal effect on rhizosphere communities may be a consequence of changes in characteristics in the environment close to mycorrhizal roots.

Abundance of arbuscular mycorrhizal fungi in relation to soil salinity around Lake Urmia in northern Iran analyzed by use of lipid biomarkers and microscopy

Saline soils around Lake Urmia in northern Iran constitute a stressed environment for plants and microbial communities, including arbuscular mycorrhizal (AM) fungi. Soil and root samples were collected from fields cultivated with the glycophytes Allium cepa L. and Medicago sativa L., and sites dominated by the halophyte Salicornia europaea L. Soil and root samples were analyzed for the AM fungal signature neutral lipid fatty acid (NLFA) 16:1ω5. The roots were also examined microscopically for mycorrhizal colonization. Each plant species was sampled across a salt gradient. Microscopic examination showed no AM fungal structures in the roots of S. europaea. The highest root colonization was recorded for M. sativa. The highest NLFA 16:1ω5 values were found in soil around M. sativa roots and the lowest in soil around S. europaea roots. We found evidence for stimulation of vesicle formation at moderate salinity levels in M. sativa, which is an indication of increased carbon allocation to mycorrhiza. On the other hand, we found a negative correlation between salinity and arbuscule formation in A. cepa, which may indicate a less functional symbiosis in saline soils.

Physicochemical Properties, Volatile Compounds and Phospholipid Classes of Silver Carp Brain Lipids

AbstractLarge amounts of utilizable by‐products are produced concomitant with silver carp processing. The lipids from fish brain contain considerable essential fatty acids which however have seldom been studied. In this study, the lipids extracted from the brain of silver carp exhibited good physicochemical properties. Forty volatile compounds were identified, of which hydrocarbons and aromatics predominated. The ratios of polar lipids and phospholipids to total lipids were 22.73 and 10.95 % respectively. Phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS) accounted for 83.9 % of the phospholipids. Major fatty acids of neutral lipids, polar lipids, PC, PE and PS differed significantly. PE had the most polyunsaturated fatty acids (PUFA), while PC, PE and PS were rich in docosahexaenoic and eicosapentaenoic acids. Moreover, the ratios of fatty acids were considered to be reasonable due to high levels of n3 PUFA. The lipids from silver carp brain have been demonstrated to be healthy and nutritious. The results herein confirm that silver carp brain lipids are a commercially and industrially feasible prospect.

Fungi Benefit from Two Decades of Increased Nutrient Availability in Tundra Heath Soil

If microbial degradation of carbon substrates in arctic soil is stimulated by climatic warming, this would be a significant positive feedback on global change. With data from a climate change experiment in Northern Sweden we show that warming and enhanced soil nutrient availability, which is a predicted long-term consequence of climatic warming and mimicked by fertilization, both increase soil microbial biomass. However, while fertilization increased the relative abundance of fungi, warming caused only a minimal shift in the microbial community composition based on the phospholipid fatty acid (PLFA) and neutral lipid fatty acid (NLFA) profiles. The function of the microbial community was also differently affected, as indicated by stable isotope probing of PLFA and NLFA. We demonstrate that two decades of fertilization have favored fungi relative to bacteria, and increased the turnover of complex organic compounds such as vanillin, while warming has had no such effects. Furthermore, the NLFA-to-PLFA ratio for 13C-incorporation from acetate increased in warmed plots but not in fertilized ones. Thus, fertilization cannot be used as a proxy for effects on warming in arctic tundra soils. Furthermore, the different functional responses suggest that the biomass increase found in both fertilized and warmed plots was mediated via different mechanisms.

Analysis of Free Fatty Acids in Blood of Healthy Person and that of Hepatitis Patient

Polyunsaturated fatty acids (PUFA) are highly susceptible to oxidation and their levels can rapidly decrease under oxidative stress [1]. A concomitant increase in monounsaturated fatty acids such as oleic and palmtoleic acids is often observed probably as a result of the activation of Δ9-desaturase [1]. Analysis of fatty acid profiles is therefore of importance. Here we describe the analysis of plasma free fatty acids (FFA) only, because the measurement of fatty acids in neutral lipids, phospholipids, and total lipids has already been well documented. Plasma FFA can, furthermore, be produced by oxidatively damaged tissues because hydrolysis of phospholipids is stimulated by oxidative stress [2].