14C Content Research Articles

Paraoxonase 2 Mediates Metabolic Reprogramming of Murine Tracheal Epithelial Cells in Response to the Quorum Sensing Molecule N‐(3‐oxododecanoyl)‐homoserine Lactone

Background The opportunistic pathogen Pseudomonas aeruginosa secretes the quorum sensing (QS) molecule N-3-oxo-dodecanoyl-l-homoserine lactone (C12) to coordinate gene expression profiles required for the infection of mammalian airways. Paraoxonase 2 (PON2), a ubiquitously-expressed intracellular enzyme cleaves and inactivates C12 via its lactonase activity to disrupt P. aeruginosa QS signaling. C12 is cytotoxic to numerous cell types in a PON2-dependent fashion at supraphysiological concentrations. Our recent work demonstrates that C12 hinders cell proliferation in a PON2-dependent manner at concentrations present in established infections. However, the detailed mechanisms remain unclear. Objective To investigate the mechanism by which C12 hinders cell proliferation at subtoxic concentrations, we monitored metabolic changes in murine tracheal epithelial cells (TECs) isolated from wild type or PON2-deficient mice using liquid chromatography-mass spectrometry (LC-MS), Seahorse real-time cell metabolic analysis, fluorescent microscopy, flow cytometry, and traditional molecular biology approaches. Methods Homozygous PON2-knockout C57BL/6 mice were generated using CRISPR/Cas9. PON2 status was confirmed by sequencing and Western Blot. Primary TECs from wild type or PON2-knockout animals were isolated, cultured, and immortalized using established protocols. Gene expression of tracheal epithelial markers (KRT5, SOX2, TP53) was determined using RT-PCR. Lysates from TECs were analyzed for PON2 activity using LC-MS. Mitochondrial respiration was monitored in TECs with or without PON2 expression treated with vehicle control or C12 using the Seahorse XF Mito Stress Test. Statistical analysis was performed using Student's unpaired t-test. Results Sequencing and western blot analysis indicate functional PON2 expression in wild type, but not PON2-KO, mice. RT-PCR analysis shows similar expression of tracheal epithelial markers in both WT and PON2-KO TECs post-immortalization. LC-MS analysis reveals PON2 enzymatic activity in WT TECs, but not PON2-KO TECs. Treatment with C12 hinders mitochondrial oxygen consumption, promotes extracellular acidification, and disrupts mitochondrial structure in TECs with PON2 expression. Conclusions These findings indicate that exposure to subtoxic concentrations of C12 alters components of cellular metabolism in a PON2-dependent manner.

The type of blood used to feed Aedes aegypti females affects their cuticular and internal free fatty acid (FFA) profiles.

Aedes aegypti, the primary vector of various arthropod-borne viral (arboviral) diseases such as dengue and Zika, is a popular laboratory model in vector biology. However, its maintenance in laboratory conditions is difficult, mostly because the females require blood meals to complete oogenesis, which is often provided as sheep blood. The outermost layer of the mosquito cuticle is consists of lipids which protects against numerous entomopathogens, prevents desiccation and plays an essential role in signalling processes. The aim of this work was to determine how the replacement of human blood with sheep blood affects the cuticular and internal FFA profiles of mosquitoes reared in laboratory culture. The individual FFAs present in cuticular and internal extracts from mosquito were identified and quantified by GC–MS method. The normality of their distribution was checked using the Kolmogorov-Smirnov test and the Student’s t-test was used to compare them. GC-MS analysis revealed similar numbers of internal and cuticular FFAs in the female mosquitoes fed sheep blood by membrane (MFSB) and naturally fed human blood (NFHB), however MFSB group demonstrated 3.1 times greater FFA concentrations in the cuticular fraction and 1.4 times the internal fraction than the NFHB group. In the MFSB group, FFA concentration was 1.6 times higher in the cuticular than the internal fraction, while for NFHB, FFA concentration was 1.3 times lower in the cuticular than the internal fraction. The concentration of C18:3 acid was 223 times higher in the internal fraction than the cuticle in the MHSB group but was absent in the NFHB group. MFSB mosquito demonstrate different FFA profiles to wild mosquitoes, which might influence their fertility and the results of vital processes studied under laboratory conditions. The membrane method of feeding mosquitoes is popular, but our research indicates significant differences in the FFA profiles of MFSB and NFHB. Such changes in FFA profile might influence female fertility, as well as other vital processes studied in laboratory conditions, such as the response to pesticides. Our work indicates that sheep blood has potential shortcomings as a substitute feed for human blood, as its use in laboratory studies may yield different results to those demonstrated by free-living mosquitoes.

Performance, carcass traits and meat quality of lambs fed with different roughage: concentrate ratios associated with variable physically effective neutral detergent fibre content

AbstractThis study evaluated the effect of roughage:concentrate (R:C) ratio associated with a variable particle size of physically effective neutral detergent fibre (peNDF8) in the forage (Tifton-85 hay) on the performance, carcass traits and meat quality of lambs. Seventy-two 4-month-old, non-castrated Santa Ines male lambs (23.5 ± 2.32 kg BW) were distributed in a completely randomized design, in a 2 × 2 factorial arrangement [two peNDF8 hay particle sizes (13 and 6 mm) and two R:C ratios (700:300 and 500:500 g/kg DM total)]. DMI, DM, NFC and TDN digestibility's, N-intake and N-faecal excretion were affected by the R:C ratio (P < 0.05). However, the N-retained was not affected by the studied variables (P > 0.05). It was observed an interaction (P < 0.05) between the peNDF8 and R:C ratios for final BW, average daily gain (ADG), colour parameters and pH 24 h. The lower roughage ratio provided greater (P < 0.05) concentrations of C14:1, C16:1–cis9, C18:1–cis9, ΣMUFA, Σn–6:Σn–3 and hypocholesterolemic/hypercholesterolemic index, enzymatic activity Δ9desaturase-C16 and -C18. Lambs fed a lower roughage diet had improved performance and feed efficiency, however, presented reduced polyunsaturated fatty acids (PUFA) concentrations in the meat, especially Σn–3 family. Higher roughage diet and larger peNDF8 particle size improved the concentrations of PUFA while decreased Σn–6:Σn–3 ratio in meat. Larger peNDF8 particle size associated with higher roughage proportion, have reduced animal performance however, it increased protein concentration, a* and C* colour parameter without affecting fatty acids profile of Longissimus lumborum muscle.

14C INTERCOMPARISON EXERCISE ON BONES AND IVORY SAMPLES: IMPLICATIONS FOR FORENSICS

ABSTRACTThe application of accelerator mass spectrometry radiocarbon (AMS 14C) dating in forensics is made possible by the use of the large excursion of the 14C concentration in the post-WWII terrestrial atmosphere due to nuclear testing as a reference curve for data calibration. By this approach high-precision analyses are possible on samples younger than ∼70 years. Nevertheless, the routine, widespread application of the method in the practice of forensics still appears to be limited by different issues due to possible complex interpretation of the results. We present the results of an intercomparison exercise carried out in the framework of an International Atomic Energy Agency (IAEA) CRP-Coordinated Research Project between three AMS laboratories in Italy, Hungary, and Switzerland. Bone and ivory samples were selected with ages spanning from background (>50 ka) to 2018. The results obtained allow us to assess the high degree of reproducibility of the results and the remarkable consistency of the experimental determinations.

РАДИАЦИОННО-ЭКОЛОГИЧЕСКИЙ МОНИТОРИНГ АГРОЭКОСИСТЕМ В РАЙОНЕ БЕЛОЯРСКОЙ АЭС

Актуальность. Поступление в окружающую среду техногенных радионуклидов при эксплуатации АЭС может привести к их аккумуляции в отдельных звеньях трофической цепи, что повлияет на формирование дозовых нагрузок на население. Сельскохозяйственная продукция и местные продукты питания, производящиеся вблизи АЭС, являются одним из основных источников поступления радионуклидов в организм человека, проживающего в районе размещения атомной электростанции. Цель: оценка современной радиационной обстановки в районе Белоярской АЭС и АО «Институт реакторных материалов» на основе созданной системы радиационно-экологического мониторинга аграрных экосистем. Объекты. Мониторинговые исследования аграрных экосистем проведены в 2013 и 2019 гг. в 30-км зоне вокруг радиационно-опасных объектов. На различном расстоянии и направлениях от них заложены контрольные участки на пашне – 15, лугопастбищных угодьях – 13 и огородах населенных пунктов – 13. На контрольных участках измеряли мощность дозы, отбирали пробы почв, продукции растениеводства, кормопроизводства и продуктов питания. Методы. Всего исследовано в 2013 г. – 137, в 2019 г. – 94 образца. В компонентах агроэкосистем оценивали содержание 40К, 226Ra, 232Th, 90Sr, 137Cs и 239,240Pu. В сельскохозяйственной и пищевой продукции дополнительно определяли 3H и 14C. Результаты. Показано, что содержание 90Sr в почве агроэкосистем в районе радиационно-опасных объектов составляет 4,3…7,2 Бк/кг, 137Cs варьирует в пределах 7,5…18,9 Бк/кг. Диапазон вариации содержания естественных радионуклидов составляет: для 40K 286…432 Бк/кг, для 226Ra 16,1…21,7 Бк/кг, для 232Th 20,1…25,5 Бк/кг. Среднее содержание 239,240Pu в почве агроэкосистем составило 0,13 Бк/кг при вариации 0,07…0,25 Бк/кг. Мощность дозы находилась в диапазоне 0,08…0,13 мкЗв/ч, при среднем 0,10 мкЗв/ч. Уровни загрязнения 137Cs пашни варьировали в пределах: 1,1…3,9 кБк/м2 в 2013 г. и 1,3…2,5 кБк/м2 в 2019 г. Диапазон данных по плотностям загрязнения 137Cs лугопастбищных угодий оказался шире: 1,5…4,5 кБк/м2 в 2013 г. и 1,6…5,2 кБк/м2 в 2019 г. Плотности загрязнения 137Cs почв огородов находились в пределах 0,9…7,7 кБк/м2. Содержание 40K в продукции растениеводства района АЭС варьировало в пределах от 48 до 526 Бк/кг, что определяется видовыми особенностями растений и характеристиками почв, где выращиваются культуры. В продукции кормопроизводства накопление 40K отмечено в диапазоне 260…543 Бк/кг, в продукции животноводства в пределах 18…97 Бк/кг. Удельная активность радионуклидов в зерне отмечена в диапазонах: для 90Sr 1,03…2,8 Бк/кг, для 137Cs 0,15…0,94 Бк/кг. Максимальные уровни накопления 137Cs зафиксированы в ячмене (0,94 Бк/кг) и были ниже норматива СанПиН в 64 раза. Среди овощей, картофеля и бахчевых максимальные уровни удельной активности как 90Sr (0,84 Бк/кг), так и 137Cs (0,26 Бк/кг) отмечались в свекле в 2013 г., однако они были ниже нормативов СанПиН в 45 и 300 раз, соответственно. В соломе зерновых среднее содержание 90Sr варьировало в пределах 2,3…3,6 Бк/кг, 137Cs 0,7…2,1 Бк/кг. В травостое этот диапазон составлял 1,2…3,5 Бк/кг для 90Sr и 0,5…1,8 Бк/кг для 137Cs, соответственно. Максимальные уровни удельной активности 90Sr в соломе (3,6 Бк/кг) оказались в 50 раз ниже норматива по содержанию этого радионуклида в кормах, по 137Cs (2,1 Бк/кг) эта разница составила 190 раз. Максимальные уровни содержания 90Sr в траве (3,5 Бк/кг) были в 14 раз ниже норматива, по 137Cs (1,76 Бк/кг) почти в 56 раз. В 2013 и 2019 гг. динамика содержания техногенных радионуклидов в молоке была разнонаправленной: по 90Sr оно несколько возросло, по 137Cs уменьшилось. Однако даже максимальные значения объемной активности 90Sr (0,41 Бк/л) и 137Cs (0,11 Бк/л) в молоке оказались ниже граничных уровней, установленных нормативами СанПиН в 60 раз по радиостронцию и в 900 раз по радиоцезию. Нормируемое содержание 137Cs в говядине (0,12 Бк/кг) в 2019 г. оказалось более чем в 1,5 тыс. раз ниже требований СанПиН. Показано, что 3H и 14C в сельскохозяйственных и пищевых продуктах в большей степени накапливаются в кормах сельскохозяйственных животных (82…255 Бк/кг), чуть меньше в продовольственном зерне (40…82 Бк/кг). Далее по степени накопления 3H и 14C следуют молоко и картофель (10…95 Бк/кг) и в наименьшей степени данные радионуклиды аккумулируются в овощах (3…8 Бк/кг). Результаты радиационно-экологического мониторинга агроэкосистем показали, что многолетние нормализованные выбросы Белоярской АЭС и АО «Институт реакторных материалов» не привели к регистрируемому увеличению содержания техногенных радионуклидов в почве, сельскохозяйственной продукции и продуктах питания по сравнению с региональным фоном. Отмечена необходимость дальнейшего изучения закономерностей накопления 3H и 14C в сельскохозяйственной и пищевой продукции района размещения АЭС.

Phosphatase and tensin homolog (PTEN) suppresses triacylglycerol accumulation and monounsaturated fatty acid synthesis in goat mammary epithelial cells

Phosphatase and tensin homolog (PTEN) is a well-known tumor suppressor in nonruminants and regulates various cellular processes including growth through dephosphorylation of phosphoinositide substrates. Although studies with bovine mammary tissue suggested a role for PTEN during lactation, its potential role in lipid metabolism remains unknown. Objectives of the present study were to determine PTEN abundance in goat mammary tissue at 2 stages of lactation (n = 6 Xinong Saanen dairy goats per stage), and to use gene-silencing and adenoviral transfections in vitro with isolated goat mammary epithelial cells (GMEC) to evaluate the role of PTEN abundance of lipid metabolism-related genes. Abundance of PTEN decreased by 51.5% at peak lactation compared with the dry period. The PTEN was overexpressed in isolated GMEC through adenoviral transfection using an adenovirus system with Ad-GFP (recombinant adenovirus of green fluorescent protein) as control, and silenced via targeted small interfering RNA (siRNA) transfection with a scrambled small interfering RNA as a negative control. Cell culture was performed for 48 h before RNA extraction, triacylglycerol (TAG) analysis, and fatty acid analysis. Overexpression of PTEN downregulated abundance of acetyl-coenzyme A carboxylase α (ACACA), fatty acid synthase (FASN), sterol regulatory element binding transcription factor1 (SREBF1), stearoyl-coenzyme A desaturase 1 (SCD1), diacylglycerol acytransferase 1 (DGAT1), 1-acylglycerol-3-phosphate O-acyltransferase 6 (AGPAT6) coupled with an increase in patatin-like-phospholipase domain containing 2 (PNPLA2), hormone-sensitive lipase (LIPE), and carnitine palmitoyltransferase 1 β (CPT1B). Furthermore, overexpressing PTEN in vitro resulted in a significant decrease in TAG concentration and concentration of C16:1. In contrast, interference of PTEN led to an opposite effect on lipid metabolism in GMEC. These changes suggested a shift from lipogenesis and esterification to lipolysis and fatty acid oxidation. Collectively, PTEN seems to play a role in monounsaturated fatty acids synthesis and lipid accumulation in GMEC.

Short-term accumulation and elimination of carbon-14 in the common carp Cyprinus carpio under laboratory conditions

This study examined the short term transfer of carbon-14 (14C) in the common carp Cyprinus carpio under laboratory conditions. Various experiments were achieved in order to investigate direct or trophic transfer for 4 days, using waterborne 14C-labelled arginine or 14C-labelled food pellets respectively. Radiolabelled food was prepared with 14C-labelled arginine or glucose in order to test how transfer kinetics might vary with the biochemical form of 14C. Elimination experiments were achieved using fish fed for 5 days on radiolabelled food and then placed under starvation for 4 days. In all experiments, water, food and fish activities were monitored every day. Different fish fractions (whole body, muscle) were sampled in order to elucidate the role of muscle as a potential storage. Results suggested that direct water-to-fish absorption rate was 20% d−1 per fish. Carps incorporated 14.3% of the absorbed 14C. Fish activity did not increase over days, due to a strong decrease in 14C concentration in the water (resulting from aquarium sorption). During trophic transfer experiments, food was entirely ingested and 14C sources rapidly assimilated. For either arginine or glucose, results suggested that 19–20% of ingested 14C was incorporated, yielding a significant increase in fish activity over days. No difference in mass-specific activity was observed among muscle and whole body. Total activity in the muscle represented 29%–32% of whole body activity, this proportion reflecting the contribution of muscle to whole body weight. During elimination experiments, results showed a significant decrease in whole body total activity and mass-specific activity with arginine. The decrease was not significant with glucose due to a great variability among fish. Results suggested that an essential amino-acid like arginine can be used as an energy source under starvation and that muscles can act as a storage for essential amino-acids.

The age of adult pilocytic astrocytoma cells

Adult pilocytic astrocytomas (PAs) have been regarded as indistinguishable from pediatric PAs in terms of genome-wide expression and methylation patterns. It has been unclear whether adult PAs arise early in life and remain asymptomatic until adulthood, or whether they develop during adulthood. We sought to determine the age and origin of adult human PAs using two types of “marks” in the genomic DNA. First, we analyzed the DNA methylation patterns of adult and pediatric PAs to distinguish between PAs of different anatomic locations (n = 257 PA and control brain tissues). Second, we measured the concentration of nuclear bomb test-derived 14C in genomic DNA (n = 14 cases), which indicates the time point of the formation of human cell populations. Our data suggest that adult and pediatric PAs developing in the infratentorial brain are closely related and potentially develop from precursor cells early in life, whereas supratentorial PAs might show age and location-specific differences.

A multi-tracer approach for understanding the functioning of heterogeneous phreatic coastal aquifers in humid tropical zones

ABSTRACT In many areas around the world, phreatic coastal aquifers are vulnerable to contamination and saltwater intrusion. This study aims to explore the hydrodynamic functioning of the coastal phreatic aquifer of the Urabá region, Colombia, based on the identification of hydrogeochemical processes and groundwater residence and transit times. Hydrodynamic data showed a fast response of the piezometric levels to precipitation with a maximum time lag of 48 h. Mean annual recharge was estimated at 19% with respect to precipitation. Another recharge mode is linked to infiltration from surface water, according to the hydrodynamic results. The main geochemical process identified is hydrolysis due to dissolved carbon dioxide, inducing silicate weathering and resulting in predominant HCO3-Ca-Mg facies. Monitoring of δ18O and δ2H compositions combined with 3H, 14C, chlorofluorocarbons (CFCs) and SF6 contents showed a fast recharge in the aquifer. Groundwater dating indicates recent waters mixed with older (>40 years) waters.

Effects of Essential Fatty Acid Supplementation on in vitro Fermentation Indices, Greenhouse Gas, Microbes, and Fatty Acid Profiles in the Rumen.

This study estimated the effect of essential fatty acid (FA) supplementation on fermentation indices, greenhouse gases, microbes, and FA profiles in the rumen. The treatments used pure FAs consisting of C18:2n-6 FA (LA), C18:3n-3 FA (LNA), or a mixture of these FAs at 1:1 ratio (Combo). In vitro rumen incubation was performed in 50 mL glass serum bottles containing 2 mg of pure FAs, 15 mL of rumen buffer (rumen fluid+anaerobe culture medium = 1:2), and 150 mg of synthetic diet (411 g cellulose, 411 g starch, and 178 g casein/kg dry matter) at 39°C for 8 h with five replications and three blanks. In rumen fermentation indices, LA exhibited highest (P < 0.05) ammonia-N and total gas volume after 8 h of incubation. Furthermore, LA presented lower (P < 0.05) pH with higher (P < 0.05) total volatile fatty acid (P = 0.034) than Combo, while LNA was not different compared with those in the other treatments. Additionally, Combo produced highest (P < 0.05) CO2 with lowest (P < 0.05) CH4. In the early hours of incubation, LA improved (P < 0.005) Fibrobacter succinogenes and Ruminococcus flavefaciens, while LNA improved (P < 0.005) Ruminococcus albus. After 8 h of incubation, LNA had lower (P < 0.05) methanogenic archaea than LA and Combo but had higher (P < 0.05) rumen ciliates than LA. R. albus was higher (P < 0.05) in LA than in LNA and Combo. It was observed that the rate of biohydrogenation of n-6 and n-3 FAs was comparatively lowest (P < 0.05) in Combo, characterized by higher C18:2n-6 and/or C18:3n-3 FA and polyunsaturated FA (PUFA) concentrations with lower (P < 0.05) concentrations of C18:0 and saturated FA and the ratio of saturated FAs to PUFAs. Therefore, this study concluded that dietary C18:2n-6 could improve populations of fibrolytic bacteria and rumen fermentation indices, but dietary mixture of pure C18:2n-6 and C18:3n-3 is recommended because it is effective in reducing enteric methane emissions and resisting biohydrogenation in the rumen with less effect on rumen microbes.

The application of environmental isotopes to conceptualize groundwater recharge in a coastal aquifer system: Case study of the West Coast Aquifer System, South Africa

Knowledge of natural recharge mechanisms of the West Coast Aquifer is vital for the implementation of water resource management strategies, which would secure groundwater resources for the region. The analysis of stable (2H and 18O) and radioactive (3H and 14C) environmental isotopes have been employed to identify the source of recharge and residence times of the shallow, confined and bedrock aquifers based on sampling conducted during 2017 and 2018. The δ18O values for groundwater ranged from −4.34 and 0.65‰ while δ2H values ranged from −18.8 and 6.8‰. Groundwater 3H activity ranged from 0.0 to 1.2 T.U, rainwater tritium was 1.4 T.U while 14C contents ranged from 0.0 to 1.2pMC. The stable isotope signatures revealed four water groups: non-evaporative shallow and deep groundwater with similar isotopic composition indicating same source of recharge; bedrock groundwater with enriched isotopic signature which show evaporation effect indicating recharge from precipitation where clay lenses are locally absent; non-evaporative shallow groundwater indicate recently infiltrated water; groundwater is not recharged by surface water when drought conditions persist. Deep groundwater in the low-plain discharge zone is recharged by seawater intrusion which is evidenced elevated chloride concentration (35700 mg/l) and enriched stable isotope composition. High tritium (>0.8 T.U) containing groundwater were found downgradient from recharge area, which confirms recent active recharge occurs a distance from postulated recharge area. Tritiated bedrock groundwater with older 14C ages had the same δ18O values as younger shallow groundwater which is consistent with it being derived from locally from low altitudes. The calculated carbon-14 residence times suggest aquifers were recharged under different climatic conditions during cooler periods of the late Pleistocene and Holocene (~2717–33000). The calculated radiocarbon age reflected in the tritium containing groundwater in the deep aquifer supports active localized recharge to deep groundwater system via focused mechanism. The application of environmental isotope methodology combined with an understanding of geology in the study area led to the development of a coherent conceptual flow model.

Analysis of mono-, di-, triacylglycerols, and fatty acids in food emulsifiers by high-performance liquid chromatography\u2013mass spectrometry

Mono- and diacylglycerols (MG/DG) of fatty acids (FA), known as emulsifiers of the type E 471, are food additives used to adjust techno-functional properties of various foodstuffs. These emulsifiers, however, are not defined single compounds but comprise, in addition to MG and DG, other constituents such as FA, triacylglycerols (TG), and glycerol. Although the emulsifiers’ compositions affect techno-functional properties of the food, knowledge of the composition is scarcely available, and the emulsifiers and their dosage are generally chosen empirically. Thus, a simple and rather inexpensive method for the simultaneous determination of FA, 1-MG, 2-MG, 1,2-DG, 1,3-DG, and TG by high-performance liquid chromatography–mass spectrometry including a straightforward quantitation strategy has been developed. Reversed-phase chromatography with gradient elution offered adequate separation of 29 considered analytes within 21 peaks, while mass-selective detection provided their unequivocal identification. The quantitation strategy based on calibration just with the C16:0 representatives of each lipid class and a corresponding response factor system has proven to provide reliable results. The determined concentrations of different mixtures comprising varying compositions and concentrations of C16:0, C18:0, and C18:1 components of each lipid class deviated < 20% (n = 351) from the respective target concentrations. Limits of decision were determined to 0.3–0.8 mg/L and limits of quantitation to 0.8–1.7 mg/L, expressed as C16:0 representatives. Application of the method to various E 471 emulsifiers provided detailed data on their chemical compositions, and calculated FA compositions matched very well those determined by common methods such as gas chromatography with flame ionization detection.

Age distribution, extractability, and stability of mineral-bound organic carbon in central European soils

Abstract. The largest share of total soil organic carbon (OC) is associated with minerals. However, the factors that determine the amount and turnover of slower- versus faster-cycling components of mineral-associated carbon (MOC) are still poorly understood. Bioavailability of MOC is thought to be regulated by desorption, which can be facilitated by displacement and mobilization by competing ions. However, MOC stability is usually determined by exposure to chemical oxidation, which addresses the chemical stability of the organic compounds rather than the bonding strength of the OC–mineral bond. We used a solution of NaOH, a strong agent for desorption due to high pH, and NaF, adding F−, a strongly sorbing anion that can replace anionic organic molecules on mineral surfaces, to measure the maximum potentially desorbable MOC. For comparison, we measured maximal potential oxidation of MOC using heated H2O2. We selected MOC samples (&gt; 1.6 g cm3) obtained from density fractionation of samples from three soil depth increments (0–5, 10–20, and 30–40 cm) of five typical soils of central Europe, with a range of clay and pedogenic oxide contents, and under different ecosystem types (one coniferous forest, two deciduous forests, one grassland, and one cropland). Extracts and residues were analysed for OC and 14C contents, and further chemically characterized by cross-polarization magic angle spinning 13C-nuclear magnetic resonance (CPMAS-13C-NMR). We expected that NaF–NaOH extraction would remove less and younger MOC than H2O2 oxidation and that the NaF–NaOH extractability of MOC is reduced in subsoils and soils with high pedogenic oxide contents. The results showed that a surprisingly consistent proportion of 58 ± 11 % (standard deviation) of MOC was extracted with NaF–NaOH across soils, independent of depth, mineral assemblage, or land use conditions. NMR spectra revealed strong similarities in the extracted organic matter, with more than 80 % of OC in the O/N (oxygen and/or nitrogen) alkyl and alkyl C region. Total MOC amounts were correlated with the content of pedogenic oxides across sites, independent of variations in total clay, and the same was true for OC in extraction residues. Thus, the uniform extractability of MOC may be explained by dominant interactions between OC and pedogenic oxides across all study sites. While Δ14C values of bulk MOC suggested differences in OC turnover between sites, these were not linked to differences in MOC extractability. As expected, OC contents of residues had more negative Δ14C values than extracts (an average difference between extracts and residues of 78 ± 36 ‰), suggesting that non-extractable OC is older. Δ14C values of extracts and residues were strongly correlated and proportional to Δ14C values of bulk MOC but were not dependent on mineralogy. Neither MOC extractability nor differences in Δ14C values between extracts and residues changed with depth along soil profiles, where declining Δ14C values might indicate slower OC turnover in deeper soils. Thus, the 14C depth gradients in the studied soils were not explained by increasing stability of organic–mineral associations with soil depth. Although H2O2 removed 90 ± 8 % of the MOC, the Δ14C values of oxidized OC (on average −50 ± 110 ‰) were similar to those of OC extracted with NaF–NaOH (−51 ± 122 ‰), but oxidation residues (−345 ± 227 ‰) were much more depleted in 14C than residues of the NaF–NaOH extraction (−130 ± 121 ‰). Accordingly, both chemical treatments removed OC from the same continuum, and oxidation residues were older than extraction residues because more OC was removed. In contrast to the NaF–NaOH extractions, higher contents of pedogenic oxides slightly increased the oxidation resistance of MOC, but this higher H2O2 resistance did not coincide with more negative Δ14C values of MOC nor its oxidation residues. Therefore, none of the applied chemical fractionation schemes were able to explain site-specific differences in Δ14C values. Our results indicate that total MOC was dominated by OC interactions with pedogenic oxides rather than clay minerals, as we detected no difference in bond strength between clay-rich and clay-poor sites. This suggests that site-specific differences in Δ14C values of bulk MOC and depth profiles are driven by the accumulation and exchange rates of OC at mineral surfaces.

Determination of low-level biogenic gasoline, jet fuel, and diesel in blends using the direct liquid scintillation counting method for 14C content

The direct liquid scintillation counting (LSC) method was investigated for quantitative measurement of 14C in low-level biogenic gasoline, jet fuel, and diesel range hydrocarbons in fuel blendstock to determine the biogenic content. Carbon-14 (14C) is an ideal tracer for biogenic fuel products, due to the depletion of 14C in fossil-based fuel. Biogenic gasoline, jet fuel, and diesel range hydrocarbons prepared from distillation of hydrotreated pyrolysis oils were blended with toluene at 1–10 wt%. The blends were analyzed by the direct LSC method using both Perkin-Elmer Quantulus and TriCarb instruments, using an internal 14C standard as an indication of signal quench. This study shows that it is feasible to accurately determine the biogenic fraction of blended fuels containing 1 wt% biogenic fuel using the direct LSC method, suggesting that direct LSC could be an option for quality assurance testing of biomass-derived liquids at co-processing facilities. The Quantulus and TriCarb instruments were found to be comparable for low-level detection of 14C in blended samples, suggesting that some instrument flexibility may be available to potential users. Quenching effects were considered and several methods for quench correction were compared.

RADIOCARBON, TRACE ELEMENTS AND PB ISOTOPE COMPOSITION OF PINE NEEDLES FROM A HIGHLY INDUSTRIALIZED REGION IN SOUTHERN POLAND

ABSTRACTWe determined the chemical composition of pine needles to monitor environmental contamination in an urban forest environment in the most industrialized part of southern Poland. The concentrations of radiocarbon (14C), trace elements (Cr, Co, Ni, Cu, Zn, Rb, Sr, Ba, Ce, Pb) and the Pb isotope composition were measured in needles from Pinus sylvestris L. growing in nine urban forests near five factories. The investigated young pine needles were collected in January 2013 and September 2013, respectively. 14C concentration was determined by liquid scintillation counter, trace elemental concentration and Pb isotope ratio were determined by ICP-MS and MC-ICP-MS, respectively. Analysis of trace metal pollution is based on the assumption that element concentrations in tree foliage represent element availability in the environment. Different space-time patterns of element accumulation in pine needles were observed. The variation in isotopic composition reflects a mix between different anthropogenic sources.

A diet supplemented with hazelnut skin changes the microbial community composition and the biohydrogenation pattern of linoleic acid in the rumen of growing lambs

The reuse of by-products from the agro-industry in animal feeding is desirable to increase the sustainability of the productions. Hazelnut skin is a by-product of the food industry and due to the high content in crude fat and phenolic compounds can be potentially used in ruminants’ diet. In this study, we characterised and compared the microbial communities of rumen digesta (RD) from lambs fed a diet supplied with hazelnut skin vs. a control diet. Microbial DNA was extracted and high-throughput sequencing of 16S rRNA gene amplicons was performed. Six genera ([Eubacterium] nodatum group, Acidaminococcus, Dialister, Erysipelotrichaceae UCG-002, Megasphaera, and Olsenella) showed a positive correlation with the concentration of C18:1 t10, and their relative abundance was higher in the RD from lambs fed the control diet, compared to the RD from lambs fed the diet supplied with hazelnut skin. The results suggest that the relative abundance of microorganisms correlated to C18:1 t10 production in the rumen of animals fed a concentrate-based diet can be reduced by the administration of hazelnut skin. Highlights A diet with hazelnut skin affected the microbial community in the rumen of lambs The relative abundance of the genus Dialister decreased with hazelnut skin Administration of hazelnut skin can be a strategy to reduce the C18:1 t10/t11 ratio

Abundance of solute carrier family 27 member 6 (SLC27A6) in the bovine mammary gland alters fatty acid metabolism.

Milk fatty acid (FA) composition is associated with the nutritional value of milk and is known to vary with the stage of lactation. Although biochemical aspects controlling FA metabolism in the bovine mammary gland are well-established, less is known about the underlying molecular mechanisms. Thus, to address some of these shortcomings, the present study sought to evaluate milk FA composition and mammary transcriptome profiles at different stages of lactation. Compared with 90 d of lactation, at 315 d of lactation, there was an increase in the concentrations of C18:2, polyunsaturated fatty acids (PUFA), and short-chain fatty acids (SCFA), and a decrease in C16:0 and long-chain fatty acids (LCFA) in milk. To further identify candidate genes and pathways responsible for these phenotypic differences, the transcriptome of bovine mammary tissue at 90 d (peak) and 315 d (late) of lactation was profiled using RNA-seq. A total of 827 differentially expressed genes were identified. Bioinformatic analysis revealed that the major differentially modulated lipid metabolic pathways were the PPAR signaling pathway, alpha-linolenic acid metabolism and linoleic acid metabolism. Compared with peak lactation, the mammary tissue at late lactation had lower abundance of genes related to FA transport and activation (CD36, SLC27A6, ACSM1, FABP3 and FABP4). Thus, to further explore the role of FA transport into mammary cells, we knocked down fatty acid transport protein 6 (solute carrier family 27 member 6, SLC27A6) in the bovine mammary epithelial cells (BMECs) using siRNA. The knockdown of SLC27A6 dramatically downregulated the mRNA abundance of genes associated with FA activation (ACSL4), oxidation (CPT1A) and transport (CD36), while the abundance of genes associated with transcription regulation (PPARG), diacylglycerol acyltransferase 1 (DGAT1), FA binding (FABP3), and desaturation (FADS2) was upregulated. In addition, SLC27A6 silenced the intracellular content of triglyceride (TG) and the percentage of C18:1cis9 and C20:4cis5,8,11,14 was greater, whereas that of C16:0 and C18:0 was lower. Overall, in vivo results indicated that LCFA transport into mammary cells during late lactation partly explains the difference in the FA profiles. In vitro analyses underscored how FA transport via SLC27A6 could dictate in part the intracellular utilization of FA for TG synthesis versus oxidation. The data provide strong support for a central role of SLC27A6 in the regulation of FA metabolism in BMECs.

Nutritional impacts of using graded levels of dietary linoleic acid on egg production, egg quality, and yolk fatty acid profile of laying ducks

There is an increased interest among poultry nutritionists to increase the linoleic acid (LA) content of the egg, which possesses many benefits for human health. This fatty acid must be provided by the diet as the bird’s body cannot synthesise it. The present study evaluated the influence of different levels of dietary LA on the productive performance, egg quality and yolk lipid profile of Longyan laying ducks. In total, 900 Longyan female laying ducks aged 24 weeks were assigned to six dietary treatments, each containing 6 replicates of 25 ducks. The six dietary treatments contained six incremental levels of LA (analysed content: 0.36, 0.66, 0.80, 1.07, 1.28, and 1.45%) and the experimental diets were offered for the following 20 weeks. The results showed that different supplemental levels of dietary LA had no effects on egg production traits, concentrations of plasma cholesterol and triglycerides, or low or high-density lipoprotein cholesterol (p > .05). There was a linear increase in yolk colour (p < .001) and yolk cholesterol (p < .005) with increasing dietary LA. With increased intake of LA, the yolk content in C18:1, C20:1 and total monounsaturated fatty acids decreased linearly (all p < .005), but the concentrations of C18:2, C18:3, C20:2, C20:3, C20:4, C20:6, and total polyunsaturated fatty acids were linearly increased (p <.008 to <.0001). The results of the present work show that LA dietary supplementation of Longyan duck layers positively modified the yolk fatty acid profile, increased the yolk cholesterol, and enhanced the yolk colour. HIGHLIGHTS Linoleic acid (LA) is an essential fatty acid that must be added to the poultry diet. This study evaluated six dietary levels of linoleic acid in laying ducks. LA dietary supplementation modified yolk colour, cholesterol and fatty acid profile.

Dietary inclusion of purified crude glycerin improves bodyweight at slaughter and affects the fatty acid profile of lamb meat

Context Crude glycerin (CG) is an energetic byproduct that generates glycerol, an energy product that is absorbed by the ruminal wall and conducted to the liver, where it is metabolised and it is converted to glucose, by the action of the enzyme glycerol kinase, in a gluconeogenesis process. Aims The study objective was to determine the effect of CG inclusion, replacing corn bran, in a total mixed ration to lambs, on carcass traits, physicochemical properties and the fatty acid (FA) profile of lamb meat. Methods Forty-four uncastrated crossbred Santa Ines × indigenous lambs were distributed in a completely randomised study, with four CG inclusion levels (0, 70, 140 and 210 g/kg in the lamb diet). Key results The addition of CG up to a level of 70 g/kg to the lamb diets promoted greater slaughter bodyweight, hot and cold carcass weight, carcass traits, and meat lipid content, and improved Warner–Bratzler shear force in meat. Inclusion of CG in the diet did not affect (P &gt; 0.05) the pH and colour parameters (lightness, redness, yellowness and chroma) of meat. The FA composition of the longissimus lumborum of lambs C14:0, C15:1, C16:0, C18:1 cis and ΣFA medium-chain were greater, and FA meat concentration of C14:1, C15:0, C17:1, C18:0, C18:2 n−3, C18:2 n−6, ΣPUFA, ΣFA-old-chain and elongase enzymatic activity were lower in lambs fed without CG and with 70 g/kg CG, compared with lambs mainly fed 140 and 210 g/kg CG. The heath indexes, atherogenicity index and desirable FAs improved by dietary CG inclusion of 210 g/kg to the diet of lambs. Conclusions CG obtained from biodiesel production can be incorporated in lamb diets up to 70 g/kg total mixed ration, replacing corn bran to improve the weight gain, meat lipid content, Warner–Bratzler shear force and FA profile of lamb meat. Meat fat-related consumers health indices improved from the biggest inclusions of CG to the diet of lambs However, the use of CG at levels 140 and 210 g/kg total mixed ration reduces the performance, carcass weight and morphometric measurements. Implications It is recommended the inclusion at a maximum level of 70 g of CG/kg DM as total mixed ration replacing corn bran improves the weight gain, cooking weight loss, Warner–Bratzler shear force, meat lipid content and consequently FA meat composition.

Exploring different methods of cellulose extraction for 14C dating.

In this study we aim to identify the optimal cellulose extraction protocol for 14C dating of wood, with a focus on glacial trees. To achieve this, we compare three cellulose extraction methods on the basis of cellulose yield and 14C age. The study is conducted on 12 wood samples of different species, in varying states of preservation with ages covering the full 14C age range. Cellulose is extracted from each sample following three different protocols selected from the literature: ABA-B, BABAB and 2Chlorox. The extracted cellulose was graphitised and dated with the MICADAS (Mini Carbon Dating System) at the ETH AMS laboratory. Although all three methods are considered efficient, the BABAB protocol, despite being a more aggressive procedure, allows the extraction of a sufficient amount of cellulose to be 14C dated and leads to the most reliable results, particularly for very old and background samples (samples with 14C content of zero).