Analysis Of Sterols Research Articles

Combining sterols with stable carbon isotope as indicators for assessing the organic matter sources and primary productivity evolution in the coastal areas of the East China Sea

To identify the sedimentary organic matter (OM) sources and reconstruct primary productivity evolution process in the coastal areas of the East China Sea (ECS), carbon, nitrogen and carbon stable isotope (δ13C) combined with sterols were studied in the surface and core sediments. The quantitative calculations of δ13C model and characteristic sterols suggested that the OM is derived from mixed marine and terrestrial inputs. Sinking marine phytoplankton was the dominant marine OM (MOM) source, with the average MOM proportion calculated by two end-member model of δ13C and characteristic sterol analysis of 73% and 62%, respectively. Terrestrial organic matter (TOM) displayed a decreasing trend seaward, attributed to the Changjiang River input as the dominant terrestrial source pathway. The decreased proportion of TOM with age in the core sediment was mainly controlled by the fluctuating changes of freshwater and sediment influxes of the Changjiang River. The sum content of epi-brassicasterol and dinosterol increased with age in recent 30 years, suggesting the increasing phytoplankton productivity. Enhanced anthropogenic nutrient inputs from the Changjiang River as well as the incremental nutrient supplement from the deep waters of the coastal upwelling area aggravated the phytoplankton blooms. Besides, the increasing ratio of epi-brassicasterol to dinosterol contents (B/D ratio) with age revealed the increasing diatom productivity relative to dinoflagellate productivity. This variation was mostly attributed to the natural forcing of the increased nutrient supplement from intensified coastal upwelling in the Zhejiang coastal mud area.

Insights in the molecular mechanisms of an azole stress adapted laboratory-generated Aspergillus fumigatus strain.

A pan-azole-resistant strain was generated in vitro, in which drug transporter overexpression was a major trait. Analyses suggested a role of the transporter inhibitor milbemycin oxime in inhibiting drug transporters and potentiating azole activity.

Quality Properties, Fatty Acid and Sterol Compositions of East Mediterranean Region Olive Oils.

In this study, important physicochemical properties, fatty acid and sterol compositions of olive oils from the olives which harvested from Mersin (Buyuk Topak Ulak, Gemlik, Sari Ulak), Adana (Gemlik), Osmaniye (Gemlik) and Hatay (Gemlik, Kargaburun, Hasebi, Halhali) in the Eastern Mediterranean region of Turkey have been investigated. Ripening index and oil yield analysis of the olives and free fatty acids, peroxide value, UV absorbance (K232, K270), fatty acid composition, sterol composition, erythrodiol+uvaol content, and total sterol analysis of the olive oil samples were carried out. The levels of free acidity in the olive oil samples ranged from 0.39% (Hatay Gemlik: HG3) to 2.23% (Mersin Gemlik: MG). Peroxide value ranged from 8.87 to 18.87 meq O2/kg. As K232 values in the oils fluctuated between 1.4370 and 2.3970, K270 values varied between 0.1270 and 0.1990. The results showed that all ΔK values were lower than the maximum legal limit of 0.01. The main fatty acid in all oil samples was oleic acid, ranging from 58.72% (Hatay Hasebi: HHs) to 74.54% (Hatay Gemlik: HG2). Palmitic acid values were within the percentage of 12.83% (Hatay Kargaburun: HK) to 18.50% (HHs). Total sterol content varied from 720.41 mg/kg (Hatay Kargaburun: HK) to 4519.17 mg/kg (Buyuk Topak Ulak: BTU). The β-sitosterol percentage of olive oils ranged from 76.12% (Adana Gemlik: AG) to 94.23% (Buyuk Topak Ulak: BTU). The results of this study indicated that variety significantly affect the quality indices, fatty acid and sterol compositions of olive oils significantly varied among varieties.

Chromatographic evaluation of tocols and sterols of processed canola oil and deodorizer distillate.

Tocopherols and tocotrienols in the combined form are known as tocols. Changes of total and individual tocols and sterols concentration of canola oil and deodorizer distillate (DD) during different processing stages were evaluated with the application of gas chromatography (GC) and high-performance liquid chromatography (HPLC). For sterols analysis, GC coupled with flame ionization detector (FID) was used while tocols in canola oil samples and DD, normal phase (NP) HPLC was applied. The results of the present study indicated that levels of total and individual tocols and sterols content were decreased during processing (neutralization to deodorization). Deodorization was found to be the most effective process for the reduction of total sterols and tocols as 55.9% and 34.2%, respectively. A high amount of tocols and sterols was observed in DD. Among tocols and sterols; beta tocopherol (β-T) and β-sitosterol were found to be in greater concentration 53.97% and 31.82%, respectively. Therefore, DD could be used as a valuable by-product in the cosmetics and food industries.

Molecular insights into symbiosis\u2014mapping sterols in a marine flatworm-algae-system using high spatial resolution MALDI-2-MS imaging with ion mobility separation

Waminoa sp. acoel flatworms hosting Symbiodiniaceae and the related Amphidinium dinoflagellate algae are an interesting model system for symbiosis in marine environments. While the host provides a microhabitat and safety, the algae power the system by photosynthesis and supply the worm with nutrients. Among these nutrients are sterols, including cholesterol and numerous phytosterols. While it is widely accepted that these compounds are produced by the symbiotic dinoflagellates, their transfer to and fate within the sterol-auxotrophic Waminoa worm host as well as their role in its metabolism are unknown. Here we used matrix-assisted laser desorption ionization (MALDI) mass spectrometry imaging combined with laser-induced post-ionization and trapped ion mobility spectrometry (MALDI-2-TIMS-MSI) to map the spatial distribution of over 30 different sterol species in sections of the symbiotic system. The use of laser post-ionization crucially increased ion yields and allowed the recording of images with a pixel size of 5 μm. Trapped ion mobility spectrometry (TIMS) helped with the tentative assignment of over 30 sterol species. Correlation with anatomical features of the worm, revealed by host-derived phospholipid signals, and the location of the dinoflagellates, revealed by chlorophyll a signal, disclosed peculiar differences in the distribution of different sterol species (e.g. of cholesterol versus stigmasterol) within the receiving host. These findings point to sterol species-specific roles in the metabolism of Waminoa beyond a mere source of energy. They also underline the value of the MALDI-2-TIMS-MSI method to future research in the spatially resolved analysis of sterols.

Multi-dimensional characterization and identification of sterols in untargeted LC-MS analysis using all ion fragmentation technology

Sterols are an important type of lipids, and play many important roles in physiological and pathological processes. However, comprehensive analysis of sterols especially identification of unknown sterols is challenging. In this work, LC-MS with all ion fragmentation (AIF) technology was developed for untargeted analysis of sterols in biological samples. AIF technology provided holistic and multi-dimensional characterization for both knowns and unknowns sterols, including accurate m/z, isotope pattern, retention time (RT), and co-eluted peak profiles between MS1 and MS2 ions in one analysis. We further developed an analysis strategy by integrating the multi-dimensional properties to support unambiguous identification of sterols, including distinguishing sterol isomers. The developed strategy enabled to identify a total of 23 sterols in mouse samples, and quantified 19 sterols in mouse liver tissues. More importantly, we demonstrated that AIF based multi-dimensional analysis provided a possibility to identify sterols without chemical standards and facilitated to discover novel compounds with sterol-like structures in biological samples. In summary, we employed the LC-MS based AIF technology to develop multi-dimensional characterization and identification of both known and unknown sterols in complex biological samples. The comprehensive analysis of sterols facilitates to provide molecular insights to many physiological and pathological activities in biology.

Green microsaponification-based method for gas chromatography determination of sterol and squalene in cyanobacterial biomass

Sterol analysis of complex matrices can be very laborious. To minimize the existing drawbacks, a new micro-method of sterols and squalene determination in cyanobacteria was developed and applied to monitor their production of Phormidium autumnale cultured heterotrophically. Sample extraction/saponification and GC analysis of the target compounds were optimized separately using Plackett-Burman design (PB) followed by a central composite rotational design (CCRD). The most influential variables were identified to maximize compound recovery. Chloroform presented the highest capability to extract all target compounds with a horizontal shaker table (HST) for homogenization in the saponification step. For the pretreatment, a small amount of chloroform was used for 90 min at 50 °C and 6 min for the saponification time. The sample introduction in the GC injector was studied by evaluating pressure and injector temperature. High response for sterols and squalene were obtained between 19 and 23 psi and at 310 °C of injection temperature. The new method was able to determine different sterol concentrations: 0.2–0.6 mg kg−1 of squalene, 5–18 mg kg−1 of stigmasterol, 6 mg kg−1 of cholesterol, and 3 mg kg−1 of β-sitosterol, showing high analytical performance and fulfilling all steps, thus proving to be a promising technique.

Hybrid 213 nm photodissociation of cationized Sterol lipid ions yield [M]+. Radical products for improved structural characterization using multistage tandem mass spectrometry

Sterols are a class of lipid molecules that include cholesterol, oxysterols, and sterol esters. Sterol lipids play critical functional roles in mammalian biology, including the dynamic regulation of cell membrane fluidity, as precursors for the synthesis of bile acids, steroid hormones and vitamin D, as regulators of gene expression in lipid metabolism, and for cholesterol transport and storage. The most common method employed for sterol analysis is high performance liquid chromatography coupled with tandem mass spectrometry (MS/MS). However, conventional collision induced dissociation (CID) methods used for ion activation during MS/MS typically fail to provide sufficient structural information for unambiguous assignment of sterol species based on their fragmentation behaviour alone. This places a significant burden on the efficiency of the chromatographic separation methods for the effective separation of isomeric sterols. Here, toward developing an improved analysis strategy for sterol lipids, we have explored the novel use of 213 nm photodissociation MS/MS and hybrid multistage-MS/MS (i.e., MSn) data acquisition approaches for the improved structural characterization of cholesterol, representative isomeric oxysterols, and cholesteryl esters. Most notably, UVPD-MS/MS of ammoniated, lithiated and sodiated adducts of cholesterol, several representative oxysterol species, and an oxosterol lipid, are shown to give rise to abundant [M]+. radical cation products, that subsequently fragment during collision induced MS3 to yield extensive structurally informative product ions, similar to those observed by Electron Ionization, and that enable their unambiguously assignment, including isomeric differentiation of oxysterols. For cholesterol esters, a reversed hybrid collision induced-MS/MS and UVPD-MS3 approach is shown to enable assignment of the sterol backbone, and localization of the site(s) of unsaturation within esterified fatty acyl chains.

Simplified LC-MS Method for Analysis of Sterols in Biological Samples.

We developed a simple and robust liquid chromatographic/mass spectrometric method (LC-MS) for the quantitative analysis of 10 sterols from the late part of cholesterol synthesis (zymosterol, dehydrolathosterol, 7-dehydrodesmosterol, desmosterol, zymostenol, lathosterol, FFMAS, TMAS, lanosterol, and dihydrolanosterol) from cultured human hepatocytes in a single chromatographic run using a pentafluorophenyl (PFP) stationary phase. The method also avails on a minimized sample preparation procedure in order to obtain a relatively high sample throughput. The method was validated on 10 sterol standards that were detected in a single chromatographic LC-MS run without derivatization. Our developed method can be used in research or clinical applications for disease-related detection of accumulated cholesterol intermediates. Disorders in the late part of cholesterol synthesis lead to severe malformation in human patients. The developed method enables a simple, sensitive, and fast quantification of sterols, without the need of extended knowledge of the LC-MS technique, and represents a new analytical tool in the rising field of cholesterolomics.

A Technology for Isolation and Analysis of Lipophilic and Hydrophilic Biologically Active Components from <i>N. sativa</i> L. Seeds.

Introduction . Seeds of Nigella sativa L. are widely known as a source of fatty oil with a very rare component-thymoquinone. The therapeutic potential of biologically active compounds of plant seeds covers a positive effect on the gastrointestinal tract, cardiovascular and immune systems. In addition, hypoglycemic, antioxidant, antitumor, oncoprotective, immunomodulating effects were found in thymoquinone. In addition to fatty oil and thymoquinone, a number of other significant compounds are present in the seeds, which also make up their own pharmacological asset. Aim. Study was to develop a processing flow chart and analyze the lipophilic and hydrophilic components of the seeds of N. sativa L. Materials and methods . The following methods were used as analytical methods: gas-liquid chromatography with a flame ionization detector - for the analysis of sterols and triterpenes; chromatography-mass spectrometry (gas-liquid chromatography with mass spectrometric detection) - for the study of essential oil; chromatography-mass spectrometry (high performance liquid chromatography with mass spectrometric detection) - to study flavonoids. To obtain individual fractions of biologically active compounds of seeds of N. sativa L., fractional extraction was used. Results and discussion . The principle of this approach in this case is to extract the entire lipid complex of seeds with n-hexane, followed by removal of the extractant. The thickened hexane extract is treated with ethyl alcohol, which extracts unsaponifiable compounds - terpenes, quinones, sterols and does not dissolve triacylglycerides. The seed meal remaining after hexane extraction is treated with ethyl alcohol 70 %, into which hydrophilic molecules, in particular flavonoids, pass. Conclusion . After transesterification, 5 compounds were identified in the lipophilic fraction of saponifiable lipids, the linoleic and oleic acids being dominant. A characteristic feature of this fraction is the presence of cis-11,14-eicosadiene acid, which can act as a marker element of the fatty oil of the seeds of N. sativa L. Sterols and triterpenes were found in the unsaponifiable fraction. The major component of this fraction is β -sitosterol. In addition to the indicated sterol, campesterol and stigmasteri are present. Triterpenes are represented by cycloartenol and its derivatives. Simple phenols, quinones and monoterpenes were found in the essential oil complex, p-cymol, thymoquinone and α-thuyen predominate. The hydrophilic fraction of the seeds of N. sativa L. includes flavonoids of the methoxylated series of flavones and kempferol glycosides.

Simultaneous Analysis of Fatty Alcohols, Fatty Aldehydes, and Sterols in Thyroid Tissues by Electrospray Ionization-Ion Mobility-Mass Spectrometry Based on Charge Derivatization

In this work, we developed a rapid and high-sensitivity method for simultaneous analyses of fatty alcohols, fatty aldehydes, and sterols by combining the optimized derivatization reaction with electrospray ionization-ion mobility-mass spectrometry (ESI-IM-MS). Pyridine and thionyl chloride were used as derivatization reagents as they were easily removed after the derivatization reaction and could generate permanently charged tags on different functional groups including hydroxyls and aldehydes. Through this one-step derivatization reaction, the sensitivity of detection for fatty alcohols, fatty aldehydes, and sterols was significantly increased. Moreover, the introduction of ion mobility spectrometry (IMS), offering an additional resolution power, ensured more sensitive and accurate detection of derivative products without increasing analytical time. Being connected with high-performance liquid chromatography, more than 15 kinds of compounds were analyzed within 4 min. Relative quantification using peak intensity ratios between d0-/d5-labeled ions were subsequently applied for analyzing these 15 kinds of compounds in human thyroid carcinoma and para-carcinoma tissues. The results showed significant differences in content of some analytes between these two kinds of tissues (p < 0.05). The correlations between most of the analytes in thyroid carcinoma tissues are better than the correlations in para-carcinoma tissues.

A comparative study of sterols in milk fat of different Indian dairy animals based on chemometric analysis

In this study, sterols in milk fat of cow, goat, buffalo and camel were analyzed for their variability across different season and species. A GC–MS-SIM (gas chromatography- mass spectrometry-single ion monitoring mode) method was developed for accurate determination of sterols through the selection of correct set of target and reference ions in different time windows. The simple and rapid method enabled accurate analysis of sterols without subjecting them to derivatization. The sterols characterized in milk fat included cholesterol, lathosterol, desmosterol, lanosterol and dihydrolanosterol. Species compared to season had a pronounced effect on variability of sterols. Among the different species, goat milk contained the highest cholesterol level (325.18 mg 100 g−1 fat) while minor sterols were most abundant in buffalo milk (20.62 mg 100 g−1 fat). The content of minor sterols: lanosterol, lathosterol, desmosterol and dihydrolanosterol in milk of different animals varied from 5.94 to 9.11, 3.01 to 7.50, 0.60 to 2.77 & 0.57 to 1.25 mg 100 g−1 fat respectively. Chemometric statistical approaches consisting of principal component analysis and hierarchical cluster analysis (PCA and HCA) were used to process the data. PCA was a suitable approach to find out the similarity and differences between different species and accounted for 96.6% of total variability in data. However, the variation based on season could not be explained well by PCA. HCAcould suitably classify the milch animals into four clusters based on sterol content.

Influence of pancreatic status on circulating plasma sterols in patients with cystic fibrosis.

Background Patients with cystic fibrosis (CF) have a reduced intestinal absorption of cholesterol and in a preliminary study we observed differences in plasma sterol profile between patients with pancreatic sufficiency (PS) and those with pancreatic insufficiency (PI). Therefore, we hypothesized that the sterol analysis may contribute to study the digestion and absorption state of lipids in patients with CF. To this aim we evaluated plasma sterols in a significant number of adult patients with CF in relation to the pancreatic status. Methods Beside cholesterol, we measured phytosterols and lathosterol as markers of intestinal absorption and hepatic biosynthesis, respectively, by gas-chromatography in plasma of adult CF patients with pancreatic sufficiency (PS-CF, n = 57), insufficiency (PI-CF, n = 97) and healthy subjects (control group, CT, n = 71). Results PI-CF patients had cholesterol and phytosterols levels significantly lower than PS-CF and CT (p < 5 × 10-10) suggesting a reduced intestinal absorption of sterols related to PI. Instead, lathosterol was significantly higher in PI-CF patients than PS-CF and CT (p < 0.0003) indicating an enhanced cholesterol biosynthesis. In PI-CF patients, phytosterols positively correlate with vitamin E (p = 0.004). Both the classes of molecules need cholesterol esterase for the intestinal digestion, thus the reduced levels of such lipids in serum from PI-CF patients may depend on a reduced enzyme activity, despite the pancreatic enzyme supplementation in all PI-CF patients. Conclusions A plasma sterols profile may be useful to evaluate the metabolic status of lipids in adult patients with CF and could help to manage the pancreatic enzyme supplementation therapy.

Is the existence of a mutualistic relationship between Lobesia botrana and Botrytis cinerea well-founded?

Some studies have highlighted benefits for Lobesia botrana by adding Botrytis cinerea mycelium to an artificial larval diet and have suggested a mutualistic relationship between the two organisms on grapevine, hypothesizing that fungal sterols were the nutritional factor involved. Because the nutritional quality of an artificial diet should be similar to grapes to allow extrapolation of the results to the field conditions, in the current study L. botrana larval performance was compared when larvae were fed on grapes (berries) or two artificial diets either with or without enrichment with B. cinerea. Based on sterol analysis, the two artificial diets had high cholesterol content, but relative to berries showed comparable and low phytosterol contents, respectively (high- and low-phytosterol, HPh, and LPh). While larval fitness on the HPh diet was similar to berries, the LPh diet led to higher mortality and worse larval performance. The addition of the fungus compensated for the shortage in the LPh diet but did not improve the HPh diet. Supplementing the LPh diet with linoleic acid, which is supplied also from B. cinerea, partially improved larval performance. In a field experiment, females did not show any egg-laying preferences towards naturally botrytized bunches. The positive effect of B. cinerea on the moth's next generation that is reported in the literature could be a consequence of fungus developed inside berry tunnels bored by larvae. Therefore, based on our data and previous reports the existence of a mutualistic relationship between L. botrana and B. cinerea is not well-founded.

Chemical and Physical Characterization of the Hackberry (Celtis australis) Seed Oil: Analysis of Tocopherols, Sterols, ECN and Fatty Acid Methyl Esters.

For the very first time, the nutritional and physicochemical properties of the oil extracted from hackberry Celtis australis fruit were investigated with the aim of possible applications of such wild fruit oil. The physicochemical properties such as peroxide value, acidity, saponification, iodine value and total fat content of the extracted oil were examined extensively. The obtained results showed that peroxide value, acidity, saponification, iodine value and total fat content of the extracted oil were found to be 4.9 meq O2/kg fat, 0.9 mg KOH/g fat, 193.6 mg KOH/g fat, 141.52 mg I2/g fat and ~5%, respectively. The predominant fatty acid found in this wild fruit is linoleic acid which was calculated to be 73.38%±1.24. In addition, gamma-tocopherol (87%) and β-sitosterol (81.2%±1.08) were the major tocopherol and sterol compositions found in Celtis australis seed oil. Moreover, equivalent carbon number (ECN) analysis has indicated that the three linoleic acids are the main composition of the triacylglycerols extracted from Celtis australis. Also, the high value of omega 6 and β-sitosterol make this oil applicable in cosmetics and pharmaceutical applications.

Preliminary Study and Observation of "Kalamata PDO" Extra Virgin Olive Oil, in the Messinia Region, Southwest of Peloponnese (Greece).

While there has been considerable research related to Koroneiki cultivar in different areas in Greece, no systematic work has been carried out on olive oil analysis from one of the most important olive-growing regions in Greece, located southwest of Peloponnese, Messinia. This work is the first systematic attempt to study the profile of Messinian olive oils and evaluate to what extent they comply with the recent EU regulations in order to be classified as “Kalamata Protected Designation of Origin (PDO)”-certified products. Quality indices were measured and detailed analyses of sterols, triterpenic dialcohols, fatty acid composition and wax content were conducted in a total of 71 samples. Messinian olive oils revealed a high-quality profile but, at the same time, results demonstrated major fluctuations from the established EU regulatory limits on their chemical parameters. Results showed low concentrations of total sterols, with 66.7% of the examined samples below the regulated set limits for Kalamata PDO status; high concentrations of campesterol, with a total of 21.7%, exceeding the legal maximum of 4.0%; and a slight tendency of high total erythrodiol content. Fatty acid composition and wax content were within the normal range expected for the extra virgin olive oil (EVOO) category. However, the narrower established PDO limits in specific fatty acids showed some fluctuations in a few cases.

Methyl Ether-Derivatized Sterols and Coprostanol Produced via Thermochemolysis Using Tetramethylammonium Hydroxide (TMAH).

Sterols are widely distributed in nature from lipids in organisms to sediments. As a conventional method, extraction and derivatization with TMS have been applied for sterol analysis, requiring a long preparation time for gas chromatography–mass spectrometry analysis. In this study, for sterol analysis, thermochemolysis using tetramethylammonium hydroxide (TMAH) was applied. This method performs hydrolysis and methylation simultaneously; thus, free and ether-bonding sterols can be analyzed as sterol methyl ethers in a relatively short time period. A sediment sample from a tideland (the Yatsu tideland, Japan) was analyzed using the TMAH method, and we detected more than 10 sterols, which include cholest-5-en-3β-ol (cholesterol), 24-ethylcholest-5-en-3β-ol (sitosterol), 24-methylcholesta-5,22E-3β-ol (brassicasterol), 24-ethylcholesta-5,24(28)Z-dien-3β-ol (isofucosterol), 4α,23,24-trimethyl-5α(H)-cholest-22E-en-3β- ol (dinosterol), and 5β(H)-cholestan-3β-ol (coprostanol). The detection of the various sterols can be attributed to multiple natural and artificial sources around the Yatsu tideland. In this paper, the mass spectra of these sterols are provided together with an interpretation of their fragmentation patterns. Additionally, the fecal pollution in the Yatsu tideland is discussed in the context of the detection of coprostanol.

Comprehensive sterol and fatty acid analysis in nineteen nuts, seeds, and kernel

Consumption of nuts and seeds is considered to have many beneficial health effects, as lowering cholesterol, incidence of cancer, or enhancement of immunity system. Among the most important lipid constituents of oils present in nuts and seeds are fatty acyls in lipid classes and phytosterols. The aim of the study was to quantify wide profile of fatty acids and phytosterols in 19 nuts, seeds, and kernel commonly available in the Czech Republic. Samples were extracted by the modified Folch procedure. Fatty acid analyses were conducted by gas chromatography. The sterols were derivatized and subsequently measured by HPLC–MS/MS procedure allowing for the separation of isobaric compounds including sterol Δ5–Δ7 isomers. Nuts and seeds contained predominantly oleic (18:1n-9) and linoleic (18:2n-6) acids, rich sources of α-linoleic acid (18:3n-3) were linseed, chestnut, walnuts and hempseed, the last being the best source of stearidonic acid (18:4n-3). The phytosterol analyses revealed majority of β-sitosterol and campesterol with the exception of pumpkin and melon seeds, rich in Δ7 sterols, which were separable from Δ5 isomers. Correlation of sterols and fatty acids content revealed positive correlation between monounsaturated/saturated fatty acids (16:1n-9, 18:1n-9, 20:1n-9, 20:0) and stigmasterol and negative correlation between fatty acids (16:1n-9, 18:1n-9) and sitostanols. In summary, our study revealed the wide profile of fatty acids and phytosterols between different nuts and seeds. Further studies are needed to confirm the positive effect of each nut and seeds for health.

The omics approach to bee nutritional landscape

BackgroundSignificant annual honey bee colony losses have been reported in the USA and across the world over the past years. Malnutrition is one among several causative factors for such declines. Optimal nutrition serves as the first line of defense against multiple stressors such as parasites/pathogens and pesticides. Given the importance of nutrition, it is imperative to understand bee nutrition holistically, identifying dietary sources that may fulfill bee nutritional needs. Pollen is the primary source of protein for bees and is critical for brood rearing and colony growth. Currently, there is significant gap in knowledge regarding the chemical and nutritional composition of pollen.MethodsTargeted sterol analysis and untargeted metabolomics were conducted on five commercially available crop pollens, three bee-collected crop pollens, three vegetable oils (often added to artificial protein supplements by beekeepers), and one commonly used artificial protein supplement.ResultsThis study reports key phytosterols and metabolites present across a spectrum of bee diets, including some of the major bee-pollinated crop pollens in the western United States. Significant differences were observed in sterol concentrations among the dietary sources tested. Among all quantified sterols, the highest concentrations were observed for 24-methylenecholesterol and further, pollen samples exhibited the highest 24-methylenecholesterol among all diet sources that were tested. Also, 236 metabolites were identified across all dietary sources examined.ConclusionInformation gleaned from this study is crucial in understanding the nutritional landscape available to all bee pollinators and may further assist in future efforts to develop comprehensive database of nutrients and metabolites present in all bee diets.

Zeytinyağı tağşişinin belirlenmesinde kromatografik yöntemlerin kullanılması

In research study, olive oil adulteration with olive pomace oil was monitored by fatty acids, ΔECN42 values and sterol analysis. To this end, virgin olive oil obtained from cv. Kilis Yaglik (KY) was mixed with olive pomace oil at different proportion (1, 5 and 10 %). Gas Chromatography (GC) was used to analyse fatty acid and sterol compositions. The fatty acids with Equivalent Carbon Number 42 (ECN42) and ΔECN42 values of pure and adulterated oils were also used to determine adulteration. Considering the results of fatty acids analysis, when olive pomace oil was mixed, the ratios of oleic acid and palmitic acid in olive oil, was decreased. The difference of theoretical and experimental ECN42 values (ΔECN42) were increased in adulterated oils. Beta-sitosterol which is important compound in the sterol composition, increased up to 81.42 % when mixed with 10 % olive pomace oil. Taking into account the Rmar values of the oil samples, adulterated oils displayed higher value than of pure oil. According to PCA analyses, oil samples took placed in three different groups according to fatty acids and TAGs profile, while in four different groups due to sterol composition. In all of the PCA analyzes, pure KY oil was clearly separated from the adulterated oils.