Stable Carbon Isotope Ratios (δ13C Values [‰]) of Individual Sterols in the Oils of C3, C4, and CAM Plants.

The compound-specific determination of δ13C values [‰] by gas chromatography interfaced with isotope ratio mass spectrometry (GC-IRMS) is a powerful analytical method to indicate minute but relevant variations in the 13C/12C ratio of sample compounds. In this study, the δ13C values [‰] of individual sterols were measured in eleven different oils of C3, C4, and CAM plants (n = 33) by GC-IRMS. For this purpose, a suitable acetylation method was developed for sterols. Nine of the eleven phytosterols identified by GC with mass spectrometry (GC/MS) could be measured by GC-IRMS. The δ13C values [‰] of individual sterols and squalene of C3 plant oils were between 3‰ and >16‰ more negative (lighter in carbon) than in C4 and CAM oils. We also showed that the blending of C4 oils into C3 oils (exemplarily conducted with one olive and one corn oil) would be precisely determined by means of the δ13C value [‰] of ß-sitosterol.

Anaerobic dihydrogen consumption of nutrient-limited aquifer sediment microbial communities examined by stable isotope analysis.

The biogeochemical consequences of dihydrogen (H2) underground storage in porous aquifers are poorly understood. Here, the effects of nutrient limitations on anaerobic H2 oxidation of an aquifer microbial community in sediment microcosms were determined in order to evaluate possible responses to high H2 partial pressures. Hydrogen isotope analyses of H2 yielded isotope depletion in all biotic setups indicating microbial H2 consumption. Carbon isotope analyses of carbon dioxide (CO2) showed isotope enrichment in all H2-supplemented biotic setups indicating H2-dependent consumption of CO2 by methanogens or homoacetogens. Homoacetogenesis was indicated by the detection of acetate and formate. Consumption of CO2 and H2 varied along the differently nutrient-amended setups, as did the onset of methane production. Plotting carbon against hydrogen isotope signatures of CH4 indicated that CH4 was produced hydrogenotrophically and fermentatively. The putative hydrogenotrophic Methanobacterium sp. was the dominant methanogen. Most abundant phylotypes belonged to typical ferric iron reducers, indicating that besides CO2, Fe(III) was an important electron acceptor. In summary, our study provides evidence for the adaptability of subsurface microbial communities under different nutrient-deficient conditions to elevated H2 partial pressures.

Systematic characterization of the influence of petroleum spill on terpene metabolism in Suaeda salsa (L.) Pall from coastal wetland: Implication by compound-specific stable isotope.

With the increasing industrialization and urbanization, the ecological environment is suffering from severe deterioration in Liaohe coastal wetland, and petroleum spill is one of the pollution sources. Suaeda salsa (L.) Pall (S. salsa), one of the predominant plants in Liaohe coastal wetland, is facing the increasing degradation. Terpenes are a class of inherent compounds in plants, and play key role in maintain the growth of plants. However, the environmental stress on the terpene metabolism remained unclear in the plants. In the present study, the influence of petroleum spill on terpene metabolism in S. salsa was systematically investigated by analysis of concentrations, compositions and stable carbon isotope. Under the stress of petroleum spill, terpene concentrations showed the decreasing trend, indicating the inhibition effect of petroleum spill on terpene synthesis in S. salsa. The proportions of Sabinene and A-humulene showed the obviously increased with the influence of petroleum spill, implying that these congeners were more sensitive to petroleum spills. The significant changes in stable carbon isotope compositions were observed for Borneol, Dl-menthol, A-humulene and (-) -@-bisabolol, with the enrichment in heavier isotopes in residual fractions. This result indicated that the heavier 13C was preferentially fixed on terpene by S. salsa under the petroleum stress. The similar change trends along the incubation time was observed for A-humulene and (-) - trans caryophyllene, which might imply that A-humulene was one of the products of (-) - trans caryophyllene in S. salsa. Overall, the findings of present study verified the influence of petroleum spill on terpene metabolism in S. salsa, and were meaningful for protecting the plants in the petroleum-pollution wetlands.

Carbon and phosphorus exchange rates in arbuscular mycorrhizas depend on environmental context and differ among co-occurring plants.

Phosphorus (P) for carbon (C) exchange is the pivotal function of arbuscular mycorrhiza (AM), but how this exchange varies with soil P availability and among co-occurring plants in complex communities is still largely unknown. We collected intact plant communities in two regions differing c. 10-fold in labile inorganic P. After a 2-month glasshouse incubation, we measured 32P transfer from AM fungi (AMF) to shoots and 13C transfer from shoots to AMF using an AMF-specific fatty acid. AMF communities were assessed using molecular methods. AMF delivered a larger proportion of total shoot P in communities from high-P soils despite similar 13C allocation to AMF in roots and soil. Within communities, 13C concentration in AMF was consistently higher in grass than in blanketflower (Gaillardia aristata Pursh) roots, that is P appeared more costly for grasses. This coincided with differences in AMF taxa composition and a trend of more vesicles (storage structures) but fewer arbuscules (exchange structures) in grass roots. Additionally, 32P-for-13C exchange ratios increased with soil P for blanketflower but not grasses. Contrary to predictions, AMF transferred proportionally more P to plants in communities from high-P soils. However, the 32P-for-13C exchange differed among co-occurring plants, suggesting differential regulation of the AM symbiosis.

Spatial distribution of selenium-mercury in Arctic seabirds.

Mercury (Hg) is a metallic trace element toxic for humans and wildlife that can originate from natural and anthropic sources. Hg spatial gradients have been found in seabirds from the Arctic and other oceans, suggesting contrasting toxicity risks across regions. Selenium (Se) plays a protective role against Hg toxicity, but its spatial distribution has been much less investigated than that of Hg. From 2015 to 2017, we measured spatial co-exposure of Hg and Se in blood samples of two seabird species, the Brünnich's guillemot (Uria lomvia) and the black-legged kittiwake (Rissa tridactyla) from 17 colonies in the Arctic and subarctic regions, and we calculated their molar ratios (Se:Hg), as a measure of Hg sequestration by Se and, therefore, of Hg exposure risk. We also evaluated concentration differences between species and ocean basins (Pacific-Arctic and Atlantic-Arctic), and examined the influence of trophic ecology on Hg and Se concentrations using nitrogen and carbon stable isotopes. In the Atlantic-Arctic ocean, we found a negative west-to-east gradient of Hg and Se for guillemots, and a positive west-to-east gradient of Se for kittiwakes, suggesting that these species are better protected from Hg toxicity in the European Arctic. Differences in Se gradients between species suggest that they do not follow environmental Se spatial variations. This, together with the absence of a general pattern for isotopes influence on trace element concentrations, could be due to foraging ecology differences between species. In both oceans, the two species showed similar Hg concentrations, but guillemots showed lower Se concentrations and Se:Hg than kittiwakes, suggesting a higher Hg toxicity risk in guillemots. Within species, neither Hg, nor Se or Se:Hg differed between both oceans. Our study highlights the importance of considering Se together with Hg, along with different species and regions, when evaluating Hg toxic effects on marine predators in international monitoring programs.

Geographical origin traceability of mulberry leaves using stable hydrogen, oxygen, and carbon isotope ratios.

Geographical discrimination of mulberry leaves is very important for their efficacy and quality as a traditional Chinese medicine. Stable hydrogen, oxygen, and carbon isotope ratios were measured in 292 mulberry leaves collected at 2 growth stages in 2 seasons from 8 regions of China. A stepwise linear discriminant analysis (LDA) approach were proposed to combine with stable isotope technology to tracing the origin of mulberry leaves. The results showed that leaves sampled in autumn were extremely depleted in 2H and 18O and slightly enriched in 13C compared with leaves sampled in summer, correlated with the effect of season, transpiration and photorespiration on stable isotopes. δ2H and δ18O of the leaves were enriched during the growth process. The overall discrimination accuracy of the autumn tender model was 81%, demonstrating that analysis of δ2H, δ18O, and δ13C is a promising technique for tracing the geographical origin of mulberry leaves, although season, growth stage and number of samples affect the accuracy of discrimination.

Evaluation of the One-Hour ¹³C-Propionate Breath Test in 49 Patients from a Single Center in Japan to Detect Vitamin B12 Deficiency.

BACKGROUND Given the unavailability of reliable biomarkers for vitamin B12 (VB12) deficiency in clinical settings, the usefulness of the ¹³C-propionate breath test (PBT), utilizing VB12 as a coenzyme of methylmalonyl-CoA in propionate metabolism, as a diagnostic modality for VB12 deficiency has been studied. However, a collection time of 2 h reduces its convenience. Hence, we evaluated the effectiveness of 1-h PBT for detecting VB12 deficiency in 49 patients with suspected VB12 deficiency. MATERIAL AND METHODS We collected 100-200 mL breath gas every 10 min until 1 h after the administration of 1 g of ¹³C-propionate from 49 patients (31 men, 18 women; median age, 70 years) with clinically suspected VB12 deficiency and calculated the ¹³CO2 recovered in the breath per hour as the recovery rate (RR [%dose/h]) from ¹³CO2/¹²CO2 using infrared isotope spectrometry. We compared the RRs between groups: (1) with serum VB12 levels ≥145 pg/mL and <145 pg/mL, (2) with mean corpuscular volume ≤100 fL and >100 fL, and 3) pre- and post-VB12 supplementation. RESULTS The RRs peaked within 30 min. The RRs at 20 min (RR20) and 30 min (RR30) were significantly lower in macrocytotic patients (41.28 vs 50.07, p=0.026 and 37.82 vs 43.93, P=0.003). The RR30 was higher in the supplemented patients (41.93 vs 32.84, P=0.024). There was no significant difference in RRs between the patients with normal and low serum VB12 levels. CONCLUSIONS The 1-h PBT can be a diagnostic modality for VB12 deficiency because 1 h is a sufficient collection time.

Traceability of Croatian extra virgin olive oils to the provenance soils by multielement and carbon isotope composition and chemometrics.

A capacity to determine the provenance of high-value food products is of high scientific and economic interest. With the aim to develop a tool for geographical traceability of Croatian extra virgin olive oils (EVOO), multielement composition and 13C/12C isotope ratio in EVOO as well as the geochemistry of the associated soils were analysed in samples collected from three regions along the Croatian Adriatic coast. Soil geochemistry was shown to influence the transfer and elemental composition of EVOO. The most discriminating variables to distinguish EVOO from different regions were S, Mo, Rb, Mg, Pb, Mn, Sn, K, V and δ13C. The predictive models achieved high sensitivity and specificity, especially when carbon isotope composition was added. The results suggest that interregional geographical traceability of Croatian EVOO is possible based on matching their multielement composition with that of the soils in the provenance area.

Unravelling the resilience of the KGK VI population from the Gumelnița site (Romania) through stable isotopes.

The Gumelnița site belongs to the Kodjadermen-Gumelnița-Karanovo VI (KGK VI) communities (c. 4700-3900 cal BC) and comprises the tell-type settlement and its corresponding cemetery. This paper reconstructs the diet and lifeways of the Chalcolithic people in the northeastern Balkans using archaeological remains found at the Gumelnița site (Romania). A multi-bioarchaeological investigation (archaeobotany, zooarchaeology, anthropology) was conducted on vegetal, animal, and human remains, alongside radiocarbon dating and stable isotope analyses (δ13C, δ15N) of humans (n = 33), mammals (n = 38), reptiles (n = 3), fishes (n = 8), freshwater mussels shells (n = 18), and plants (n = 24). According to the results of δ13C and δ15N values and FRUITS, the inhabitants of Gumelnița had a diet based on crops and using natural resources, such as fish, freshwater molluscs and game. Although domestic fauna was occasionally exploited for meat, it had a role in providing secondary products. Crops were heavily manured, and chaff and other crop waste may have been necessary fodder for cattle and sheep. Dogs and pigs fed on human waste, although the diet of the latter is more similar to that of wild boars. Foxes had a diet close to dogs, which may indicate synanthropic behaviour. Radiocarbon dates were calibrated with the percentage of freshwater resources obtained by FRUITS. As a result, the corrected dates for the freshwater reservoir effect (FRE) have a delay of an average of 147 years. According to our data, this agrarian community developed a subsistence strategy under the pressure of some climatic changes that started after 4300 cal BC, corresponding to KGK VI rapid collapse/decline episode tracked recently (that begins around 4350 cal BC). This matching of our data in the two models (climatic and chrono-demographic) allowed us to capture the economic strategies that led to the resilience of those people more than other contemporary KGK VI communities.

Uncovering the Ediacaran phosphorus cycle.

Phosphorus is a limiting nutrient that is thought to control oceanic oxygen levels to a large extent1-3. A possible increase in marine phosphorus concentrations during the Ediacaran Period (about 635-539 million years ago) has been proposed as a driver for increasing oxygen levels4-6. However, little is known about the nature and evolution of phosphorus cycling during this time4. Here we use carbonate-associated phosphate (CAP) from six globally distributed sections to reconstruct oceanic phosphorus concentrations during a large negative carbon-isotope excursion-the Shuram excursion (SE)-which co-occurred with global oceanic oxygenation7-9. Our data suggest pulsed increases in oceanic phosphorus concentrations during the falling and rising limbs of the SE. Using a quantitative biogeochemical model, we propose that this observation could be explained by carbon dioxide and phosphorus release from marine organic-matter oxidation primarily by sulfate, with further phosphorus release from carbon-dioxide-driven weathering on land. Collectively, this may have resulted in elevated organic-pyrite burial and ocean oxygenation. Our CAP data also seem to suggest equivalent oceanic phosphorus concentrations under maximum and minimum extents of ocean anoxia across the SE. This observation may reflect decoupled phosphorus and ocean anoxia cycles, as opposed to their coupled nature in the modern ocean. Our findings point to external stimuli such as sulfate weathering rather than internal oceanic phosphorus-oxygen cycling alone as a possible control on oceanic oxygenation in the Ediacaran. In turn, this may help explain the prolonged rise of atmospheric oxygen levels.

A Toolbox for Glutamine Use in Dissolution Dynamic Nuclear Polarization: from Enzymatic Reaction Monitoring to the Study of Cellular Metabolic Pathways and Imaging.

Glutamine is under scrutiny regarding its metabolic deregulation linked to energetic reprogramming in cancer cells. Many analytical techniques have been used to better understand the impact of the metabolism of amino acids on biological processes, however only a few are suited to work with complex samples. Here, we report the use of a general dissolution dynamic nuclear polarization (D-DNP) formulation using an unexpensive radical as a multipurpose tool to study glutamine, with insights from enzymatic modelling to complex metabolic networks and fast imaging. First, hyperpolarized [5-13 C] glutamine is used as molecular probe to study the kinetic action of two enzymes: L-asparaginase that has been used as an anti-metabolic treatment for cancer, and glutaminase. These results are also compared with those acquired with another hyperpolarized amino acid, [1,4-13 C] asparagine. Second, we explored the use of hyperpolarized (HP) substrates to probe metabolic pathways by monitoring metabolic profiles arising from hyperpolarized glutamine in E. coli extracts. Finally, a highly concentrated sample formulation is proposed for the purpose of fast imaging applications. We think that this approach can be extended to formulate other amino acids as well as other metabolites and provide complementary insights into the analysis of metabolic networks.

Revisiting marine redox conditions during the Ediacaran Shuram carbon isotope excursion.

The Neoproterozoic carbonate record contains multiple carbon isotope anomalies, which are the subject of intense debate. The largest of these anomalies, the Shuram excursion (SE), occurred in the mid-Ediacaran (~574-567 Ma). Accurately reconstructing marine redox landscape is a clear path toward making sense of the mechanism that drives this δ13 C anomaly. Here, we report new uranium isotopic data from the shallow-marine carbonates of the Wonoka Formation, Flinders Ranges, South Australia, where the SE is well preserved. Our data indicate that the δ238 U trend during the SE is highly reproducible across globally disparate sections from different depositional settings. Previously, it was proposed that the positive shift of δ238 U values during the SE suggests an extensive, near-modern level of marine oxygenation. However, recent publications suggest that the fractionation of uranium isotopes in ferruginous and anoxic conditions is comparable, opening up the possibility of non-unique interpretations of the carbonate uranium isotopic record. Here, we build on this idea by investigating the SE in conjunction with additional geochemical proxies. Using a revised uranium isotope mass balance model and an inverse stochastic carbon cycle model, we reevaluate models for δ13 C and δ238 U trends during the SE. We suggest that global seawater δ238 U values during the SE could be explained by an expansion of ferruginous conditions and do not require a near-modern level of oxygenation during the mid-Ediacaran.

A small-scale neutral alumina column chromatography method for carbon isotope determination of hopanes in crude oils or rock extracts.

This paper presents a small-scale column chromatography method for separating hopanes in crude oil or rock extracts using neutral alumina as a solid phase adsorbent and a Pasteur pipette as a separation device. Three oil samples were selected to study the effect of solid phase adsorbent type and column length on the separation of hopanes. The oil samples were eluted with mixed reagents (V hexane: V petroleum ether = 8:2) and collected at intervals of 0.5 ml. Ten Fractions were collected and tested for the compounds using GC-MS. A quantitative approach was used to reveal distribution characteristics of compounds in each eluted Fraction. Experimental results showed that 100-200 um neutral alumina exhibited significant differences in the adsorptive capacity of biomarkers from oil samples and rock extracts. The elution order of the biomarkers in the chromatographic column (the length is 180 mm) was n-alkanes, steranes and hopanes. The separation of hopanes could be realized by collecting the eluted Fractions 4 and 5. Compared with the urea complexation, the purity of hopanes separated by column chromatography was higher. The concentration of n-alkanes (nC16-nC34) could be reduced from 1.99 to 4.83 mg/ml to 0.79-0.94 mg/ml, and the content of steranes can be reduced from the original 12% to 0.45%. Residual n-alkanes and steranes were not visible in the GC-MS detection. The Total Ion Chromatography (TIC) of hopanes was consistent with the distribution characteristics of the m/z191 mass chromatogram. The isolated hopanes could meet the detection requirements of isotope ratio mass spectrometry. The C29Ts/C29αß ratio of hopanes decreased gradually from 1.63 to 0.73 as the column length increased. It is speculated that the variation of the C29Ts/C29αß ratio is not only affected by maturity but also by the oil and gas migration. This method is a new attempt in the field of compound purification and can be widely used in the study of stable carbon isotopes of hopanes monomeric hydrocarbons.

Usefulness of serum androgen isotope ratio mass spectrometry (IRMS) to detect testosterone supplementation in women.

The detection of testosterone intake is facilitated by monitoring the urinary steroid profile in the athlete biological passport. This technique can be used with confidence to identify target samples for isotope ratio mass spectrometry. Regrettably, most research has been performed on male subjects resulting in a method that does not account for females' steroid concentration and/or variation. This study evaluates the usefulness of the carbon isotope ratio (CIR) in serum of female subjects. Two steroid sulphates are targeted in serum, androsterone and epiandrosterone. Both exhibit statistically significant depletion of their CIR after 10 weeks of daily (10 mg) transdermal testosterone administration. Of the 21 female subjects, samples from six individuals were identified as adverse analytical findings; additionally, four were found atypical considering the serum CIR. The urinary athlete biological passport was not sufficiently sensitive to identify target serum samples for isotope ratio mass spectroscopy. Of the six with a suspicious passport, only two could be confirmed using the serum CIR of androsterone and epiandrosterone. This study shows that CIR analysis in serum cannot be considered the sole confirmatory solution to detect testosterone doping in women due to low sensitivity. However, this analysis has the potential to be used as a complementary method in certain situations to confirm exogenous testosterone in women.

Total Liver Vitamin A Reserves, Determined With 13C2-Retinol Isotope Dilution, are Similar Among Tanzanian Preschool Children in Areas With Low and High Vitamin A Exposure.

BACKGROUND: In Tanzania, some districts have single vitamin A (VA) interventions and others have multiple interventions. There is limited information on total liver VA reserves (TLRs) among preschool children (PSC) in Tanzania. OBJECTIVES: We assessed total body VA stores (TBSs) and TLRs among PSC living in 2 districts with low and high exposures to VA interventions using 13C-retinol isotope dilution. METHODS: A cross-sectional, health facility-based study was conducted in 2 districts with access to VA supplementation only (low exposure to VA interventions) or multiple interventions (high exposure to VA interventions) to determine TLRs in 120 PSC aged 36-59 months. A questionnaire was used to collect data. Height and weight were measured, and the prevalence of undernutrition was based on z-scores. Blood samples were collected for measurement of TBSs, TLRs, retinol, biomarkers of infection and inflammation, and hemoglobin. 13C2-retinyl acetate (1.0 µmol) was administered to each child after blood collection, and the second sample was taken 14 days later. Serum was analyzed with HPLC and gas chromatography-combustion-isotope ratio mass spectrometry. Mann-Whitney U test was used to compare medians of nonnormally distributed variables. Pearson χ2 test was used to assess associations between 2 categorical variables. RESULTS: Median TBSs differed between PSC from low-exposure (196 µmol; IQR, 120 µmol) and high-exposure (231 µmol; IQR, 162 µmol) intervention areas (P = 0.015). Median TLRs were 0.23 µmol/g liver (IQR, 0.14 µmol/g liver) and 0.26 µmol/g liver (IQR, 0.16 µmol/g liver) from low- and high-exposure areas, respectively, which did not significantly differ (P = 0.12). Prevalences of VA deficiency (VAD; ≤0.1 µmol/g liver) were 6.3% and 1.7% for PSC from low- and high-exposure areas, respectively. There was no significant difference in VAD (P = 0.25). No child had hypervitaminosis A (≥1.0 µmol/g liver). CONCLUSIONS: TLRs in Tanzanian PSC from 2 districts did not differ between low and high exposures to VA interventions. The majority had adequate VA stores. VAD in the study area presented a mild public health problem.

δ18O compound-specific stable isotope assessment: An advanced analytical strategy for sophisticated adulterations detection in essential oils - Application to spearmint, cinnamon, and bitter almond essential oils authentication.

Natural plant extracts are primarily used as raw materials in the cosmetic and perfumery industry. However, adulterations with petrochemical products are occurring in the market, leading to non-100% natural products. Several analytical techniques such as impurity detection or enantioselective ratio assessments have been previously described as good indicators to detect any addition of synthetic products, but these techniques are ineffective with novel type of synthetic pathways such as semisynthesis. In order to improve authentication, development of advanced analytical strategies such as δ18O stable isotopic ratios assessment was tested on spearmint, cinnamon and bitter almond essential oils major metabolites (carvone, (E)-cinnamaldehyde, and benzaldehyde). Natural δ18O mean values (δ18OCarvone = 18.4‰; δ18OCinnamaldehyde = 13.9‰; δ18OBenzaldehyde = 16.5‰) were found to be higher than semisynthetic origin for the 3 studied molecules (δ18OCarvone = 9.2‰; δ18OCinnamaldehyde = 8.8‰; δ18OBenzaldehyde = 10.9‰). These measurements proved to be efficient to discriminate natural and semisynthetic origins of these components and therefore potentially lead to a novel way to authenticate natural products.

Analysis of the Amine Submetabolome Using Novel Isotope-Coded Pyrylium Salt Derivatization and LC-MS: Herbs and Cancer Tissues as Cases.

The amine submetabolome, including amino acids (AAs) and biogenic amines (BAs), is a class of small molecular compounds exhibiting important physiological activities. Here, a new pyrylium salt named 6,7-dimethoxy-3-methyl isochromenylium tetrafluoroborate ([d0]-DMMIC) with stable isotope-labeled reagents ([d3]-/[d6]-DMMIC) was designed and synthesized for amino compounds. [d0]-/[d3]-/[d6]-DMMIC-derivatized had a charged tag and formed a set of molecular ions with an increase of 3.02 m/z and the characteristic fragment ions of m/z 204.1:207.1:210.1. When DMMIC coupled with liquid chromatography-mass spectrometry (LC-MS), a systematic methodology evaluation for quantitation proved to have good linearity (R2 between 0.9904 and 0.9998), precision (interday: 2.2-21.9%; intraday: 1.0-19.7%), and accuracy (recovery: 71.8-108.8%) through the test AAs. Finally, the methods based on DMMIC and LC-MS demonstrated the advantaged application by the nontargeted screening of BAs in a common medicinal herb Senecio scandens and an analysis of metabolic differences among the amine submetabolomes between the carcinoma and paracarcinoma tissues of esophageal squamous cell carcinoma (ESCC). A total of 20 BA candidates were discovered in S. scandens as well as the finding of 13 amine metabolites might be the highest-potential differential metabolites in ESCC. The results showed the ability of DMMIC coupled with LC-MS to analyze the amine submetabolome in herbs and clinical tissues.

Herd management and subsistence practices as inferred from isotopic analysis of animals and plants at Bronze Age Politiko-Troullia, Cyprus.

The Bronze Age village of Politiko-Troullia, located in the foothills of the copper-bearing Troodos mountains of central Cyprus, was occupied ~2050-1850 cal BCE. Excavated evidence shows that community activities included copper metallurgy (ore processing, smelting and casting), crop cultivation, and rearing of livestock. Faunal analysis reveals day-to-day subsistence practices that included consumption of sheep, goat, cattle, and pig, as well as community-scale ritual feasting focused on fallow deer, Dama dama mesopotamica. In this paper, we present bone collagen stable isotope data from these taxa to infer how these animals were managed. We incorporate stable isotope baselines calculated from modern cereal grains and compare these to archaeological seeds from Politiko-Troullia. Mean values of δ13C and δ15N cluster for livestock consistent with a diet of C3 plants, with a wider range in goats that suggests free-browsing herds. Higher δ15N values in cattle may reflect supplemental feeding or grazing in manured fields. Plant isotope values suggest livestock diets were predominantly composed of cultivated taxa. In contrast, deer and pig bones produce more negative mean δ13C and δ15N values suggesting that the villagers of Politiko-Troullia complemented their management of domesticated animals with hunting of wild deer and feral pigs in the woodlands surrounding their village.

Chimeric inheritance and crown-group acquisitions of carbon fixation genes within Chlorobiales: Origins of autotrophy in Chlorobiales and implication for geological biomarkers.

The geological record of microbial metabolisms and ecologies primarily consists of stable isotope fractionations and the diagenetic products of biogenic lipids. Carotenoid lipid biomarkers are particularly useful proxies for reconstructing this record, providing information on microbial phototroph primary productivity, redox couples, and oxygenation. The biomarkers okenane, chlorobactane, and isorenieratene are generally considered to be evidence of anoxygenic phototrophs, and provide a record that extends to 1.64 Ga. The utility of the carotenoid biomarker record may be enhanced by examining the carbon isotopic ratios in these products, which are diagnostic for specific pathways of biological carbon fixation found today within different microbial groups. However, this joint inference assumes that microbes have conserved these pathways across the duration of the preserved biomarker record. Testing this hypothesis, we performed phylogenetic analyses of the enzymes constituting the reductive tricarboxylic acid (rTCA) cycle in Chlorobiales, the group of anoxygenic phototrophic bacteria usually implicated in the deposition of chlorobactane and isorenieretane. We find phylogenetically incongruent patterns of inheritance across all enzymes, indicative of horizontal gene transfers to both stem and crown Chlorobiales from multiple potential donor lineages. This indicates that a complete rTCA cycle was independently acquired at least twice within Chlorobiales and was not present in the last common ancestor. When combined with recent molecular clock analyses, these results predict that the Mesoproterzoic lipid biomarker record diagnostic for Chlorobiales should not preserve isotopic fractionations indicative of a full rTCA cycle. Furthermore, we conclude that coupling isotopic and biomarker records is insufficient for reliably reconstructing microbial paleoecologies in the absence of a complementary and consistent phylogenomic narrative.

[Effects of Trichoderma on nitrogen absorption and use efficiency in Lycium chinense roots under saline stress]. / æœ¨éœ‰å¯¹ç›æ¸é€†å¢ƒä¸‹æž¸æžæ ¹ç³»æ°®ç´ å¸æ”¶å’Œæ°®ç´ åˆ©ç”¨æ•ˆçŽ‡çš„å½±å“.

To clarify the mechanisms underlying the improvement of Trichoderma on Chinese wolfberry (Lycium chinense) growth under saline stress, we analyzed the effects of application of organic fertilizer, Trichoderma agent and fertilizer on nitrogen uptake, assimilation, accumulation and use efficiency in Chinese wolfberry, based on a pot experiment with coastal saline soil. The organic fertilizer was the sterilization substance of Trichoderma fertilizer without viable Trichoderma, without any difference in the content of nutrients (such as nitrogen, phosphorus and potassium) between them. The results showed that the application of organic fertilizer, Trichoderma agent and ferti-lizer significantly increased NO3- and NH4+ influx rate in meristematic zone and NO3- influx rate in maturation zone of roots. The magnitude of such enhancement was greater in the application with Trichoderma fertilizer than organic fertilizer. Compared with the control, the application of Trichoderma agent and fertilizer significantly increased root, stem and leaf biomass and nitrogen content as well as plant nitrogen accumulation, strengthened root and leaf nitrate reductase, nitrite reductase and glutamine synthetase activities, and elevated nitrogen uptake efficiency, photosynthetic rate, stable carbon isotope abundance and photosynthetic nitrogen use efficiency. For all those variables, the beneficial effect was obviously stronger in the application with Trichoderma fertilizer than organic fertilizer. Therefore, Trichoderma facilitated nitrogen uptake, assimilation and accumulation in Chinese wolfberry under saline stress, improved photosynthetic carbon fixation ability and nitrogen use efficiency, and ultimately promoted plant growth.