Search

To explore the impact of gamma irradiation on the physicochemical properties and micronutrient contents of tiger nut oil (TNO), tiger nuts were irradiated at 0, 2, 4, 6 and 8 kGy and stored for 0 and 90 days. The physicochemical indexes, fatty acids, and the contents of tocopherols, sterols and phospholipids in TNO were identified and the structure was analyzed by FTIR. The results revealed that irradiation had no significant influence on the fatty acids of TNO, but increased its physicochemical indexes. Also, bioactive constituents, for instance, tocopherols and carotenoids, decreased with increasing irradiation dose. The phospholipid content increased with irradiation dose, but total sterols increased only at an irradiation dose of 2 kGy. FTIR confirmed that irradiation disrupted the structure of triacylglyceride, exhibiting a minor change in peaks at 3007, 2925, 2855, 1158, 1094 and 1032 cm− 1. After 90 days of storage, both irradiated and unirradiated samples showed similar deterioration in oil quality indices compared to the initial storage period. It is recommended that gamma irradiation of tiger nuts should be limited to less than 2 kGy. [ABSTRACT FROM AUTHOR]

EH (Euphorbia Humifusa) is commonly known as ground spurge, contains various compounds such as flavonoids, triterpenes, coumarins, sterols, tannins, and phenolic acids. It exerts a wide spectrum of properties including anti-bacterial, anti-inflammatory, Antioxidant, anti-viral, hypoglycemic, and anti-tumor. In this article, we focus on the antitumor effects of EH and its active constituents, providing evidence for further research on this medicinal herb. [ABSTRACT FROM AUTHOR]

The variations of the content of the main classes of lipids in the vacuolar membrane under oxidative stress have been investigated. The data obtained suggest the possibility of promoting the autophagy process. During autophagy, membrane contact sites, which are raft structures, have been established between tonoplast and autophagosomes. The results showed a significant increase in the content of raft-forming lipids (sterols, sphingolipids and lipids enriched with saturated fatty acids), what induce an elevation the number of membrane contact sites and activation of such a protective mechanism as autophagy under oxidative stress. [ABSTRACT FROM AUTHOR]

In 1957 Abbott and Ballantine described a highly toxic activity from a dinoflagellate isolated from the English Channel in 1949 by Mary Park. From a culture maintained at Plymouth Laboratory since 1950, we have been able to isolate two toxic molecules (abbotoxin and 59-E-Chloro-abbotoxin), determine the planar structures by analysis of HRMS and 1D and 2D NMR spectra, and found them to be karlotoxin (KmTx) congeners. Both toxins kill larval zebrafish with symptoms identical to those described by Abbot and Ballantine for gobies (Gobius virescens). Using surface plasma resonance the sterol binding specificity of karlotoxins is shown to require desmethyl sterols. Our results with black lipid membranes indicate that karlotoxin forms large-conductance channels in the lipid membrane, which are characterized by large ionic conductance, poor ionic selectivity, and a complex gating behavior that exhibits strong voltage dependence and multiple gating patterns. In addition, we show that KmTx 2 pore formation is a highly targeted mechanism involving sterol-specificity. This is the first report of the functional properties of the membrane pores formed by karlotoxins and is consistent with the initial observations of Abbott and Ballantine from 1957. [ABSTRACT FROM AUTHOR]

To study the mechanisms of protection of the cell membranes and macromolecules from cold, the composition of osmolytes, membrane lipids, and their fatty acids in a submerged culture of Mucor flavus was analyzed in growth dynamics at 20 and 4°C. This micromycete is psychrotolerant, having a wide growth temperature range (from –2 to 25°C) with an optimum at 20°C. Mucor flavus has a high growth rate (15 mm/day at 20°C, 4 mm/day at 0°C). At both temperatures, phosphatidic acids and phosphatidylethanolamines were predominant in the composition of membrane lipids, while phosphatidylcholines were the minor components. The main difference in the composition of membrane lipids was the threefold lower share of sterols at 4°C. During growth under optimal conditions, the proportion of phosphatidic acids decreased against the background of a slight increase in the levels of sterols, phosphatidylethanolamines, and phosphatidylcholines, while at 4°C the proportion of phosphatidic acids decreased slightly and the proportion of phosphatidylcholines increased. The fatty acids composition of phospholipids during growth at 20°C did not change significantly; linoleic, oleic, linolenic, and palmitic acids were predominant. At 4°C, the proportion of palmitic acid decreased and that of oleic acid increased, while the proportion of γ-linolenic acid decreased by half while that of α-linoleic acid increased. However, these changes did not lead to a significant change in the unsaturation degree of phospholipids, which varied between 1.5 and 1.6. Trehalose and glucose were the predominant osmolytes of the cytosol; glycerol was present in minor amounts only at 4°C. At both temperatures, the amount of osmolytes reached 3% of the dry weight in the course of growth, and the proportion of trehalose reached 70%. At both temperatures, a constant composition of osmolytes and slight changes in the composition of membrane lipids and their degree of unsaturation were observed, which probably contributes to the high growth rate of the fungus over a wide temperature range. [ABSTRACT FROM AUTHOR]

Allelochemicals are secondary metabolites which function as a natural protection against grazing activities by algae and higher plants. They are one of the major metabolites engaged in the interactions of organisms. The chemically mediated interactions between organisms significantly influence the functioning of the ecosystems. Most of these compounds are secondary metabolites comprising sterols, terpenes, and polyphenols. These compounds not only play a defensive role, but also exhibit biological activities such as antioxidants, anti-cancer, anti-diabetes, anti-inflammation, and anti-microbial properties. This review article discusses the current understanding of the allelochemicals of seaweeds and their bioprospecting potential that can bring benefit to humanity. Specifically, the bioactive substances having specific health benefits associated with the consumption or application of seaweed-derived compounds. The properties of such allelochemicals can have implications for bioprospecting pharmaceutical, nutraceutical and cosmetic applications. [ABSTRACT FROM AUTHOR]

Tocopherol and sterol are non-dietary functional molecules in sunflower oil, which act as antioxidants, reduce cholesterol and improve immunity against diseases. The present study was designed to determine tocopherol and sterol contents in 13 high and two low oleic acid sunflower hybrids across two seasons (spring and autumn) and four locations under subtropical conditions of Pakistan with contrasting reproductive phase temperatures. The results showed that tocopherol and sterol contents varied across the seasons and locations. Autumn planting produced high tocopherol content. Moreover, locations under high temperature during reproductive phase negatively affected the sterol and tocopherol contents. High oleic acid hybrids yielded 38% higher tocopherol content than low oleic acid hybrids. High oleic acid hybrids produced higher sterol contents at all locations and seasons. Hybrids such as H4 and H5 are considered stable due to comparatively close values of tocopherol and sterol contents across the four locations when compared with standard checks and other hybrids during spring season as indicated from various stability parameters. Hybrids H8, H4 and H5 also manifested higher magnitude of heterosis for tocopherol and sterol contents that may be due to overdominance gene action. Breeding lines such as B.116.P, B.112.P and RH.365 were positive combiners for the investigated traits, thus likely carrying positive alleles for both tocopherol and sterol traits. [ABSTRACT FROM AUTHOR]

Phytosterols (PSs), a class of naturally occurring bioactive lipid compounds, have been found to possess a significant cholesterol-lowering effect. In developing countries, the consumption of rapeseed oil is the primary pathway of PS intake for the general population. However, developing low-cost, real-time, and high-throughput screening techniques for PSs remains a challenge. Here, a Cu-based nanocomposite CuOx@C was synthesized via a simple method of the calcination of HKUST-1 and systematically characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The CuOx@C demonstrated excellent peroxidase-like (POD-like) activity, functioning as a peroxidase mimic to facilitate the catalysis of 3,3′,5,5′-tetramethylbenzidine (TMB) into its oxidized form (oxTMB), thereby initiating a discernible color response. On the basis of this discovery, a CuOx@C-based colorimetric method for detecting total sterols in rapeseed was successfully constructed via cascade reactions. After optimizing the conditions, the high-throughput screening of total sterols in rapeseed could be completed in only 21 min, which significantly facilitated the sensing of PSs. A linear range of 0.6–6 mg/g was achieved for the detection of total sterols in rapeseed samples, thereby satisfying the requirements for detection. In addition, due to the high stability of CuOx@C and the specificity of cholesterol oxidase, the developed method had excellent stability and selectivity toward PSs, indicating that this work has huge prospects for commercial application. This innovative work overcomes the limitation of the instrumental method and provides a portable and reliable tool for total sterols detection. It can also facilitate the development of oilseeds with a high content of PSs. [ABSTRACT FROM AUTHOR]

The influence of toxic concentrations of copper ions (100 and 500 μM) on the composition of sterols in the vacuolar membrane of beet roots was studied (Beta vulgaris L.). As a result of the studies, 12 compounds were identified in the free sterol (FS) fraction and 11 compounds in the sterol ester (ES) fraction. The ES contained compounds that were not found in the FS. Interestingly, the total content of these biologically active compounds increased at 500 µM Cu2+. A decrease in such triterpenes as lanosta-7,9(11)-diene-3β,18,20-triol, 3,18-diacetate, (20R)-(C34N54O5) was observed in FS and ES. In the FS fraction, the content of the compound 7,8-epoxylanostan-11-ol, 3-acetoxy- increased under stress, while its amount decreased in the ES. It has been established that the total content ∆5-sterols, under normal conditions and under stress, amounted to no more than 33% in the fraction of free sterols and 21% in the fraction of sterol esters. The predominant sterol was β-sitosterol. Its content decreased under the stress conditions studied in both sterol fractions. The results obtained show that the fractions of tonoplast sterols (FS and ES) are represented not only by ∆5-sterols, which are mainly studied in works devoted to membranology and lipidology of plants, but also by triterpene compounds and other substances with biological activity. The discovered substances may possibly affect the biophysical parameters of the tonoplast and the metabolic processes of the cell in which the vacuolar membrane is involved. The identified compounds actively responded to the toxic effects of Cu2+ ions, which can be considered as one of the mechanisms for protecting the plant cell from stress. [ABSTRACT FROM AUTHOR]

The effect of He-Ne laser radiation on the composition and content of cell membrane components, namely phospholipids (PL) and sterols, in wheat callus tissues was studied by chromato-mass spectrometry and thin-layer chromatography. It was shown that irradiation of calluses with laser light at a dose of 3.6 J/cm2 resulted in significant changes in the content of these components. Thus, the content of phosphatidylinositol increased in irradiated callus by 8 times, phosphatidylethonolamine by 2 times, and the content of phosphatidic acid decreased by 20% of the sum of PL. For sterols it was found that irradiation caused the most significant changes in the content of β-sitosterol dominant in plants (increase from 1453 ± 170 μg/g dry weight in unirradiated control to 2001 ± 111 μg/g dry weight 1 h after exposure); due to this, the total content of sterols also increased. The analysis of the obtained results suggests that PLs and sterols, primarily those for which regulatory and signaling functions are known, participate in the reaction of plant tissue to exposure to low-intensity He-Ne laser irradiation. This participation is realized as a stress (nonspecific) response to intense radiation. [ABSTRACT FROM AUTHOR]

All eukaryotes use sterols as structural components in cell membranes and as precursors for key hormones. However, arthropods are unique among eukaryotes because they cannot synthesize sterols de novo and must acquire sterols through diet. Cholesterol is the dominant sterol in most insects; however, because plants contain little cholesterol, most insect herbivores convert phytosterols to cholesterol. An additional challenge for plant-feeding insects is that only limited types of phytosterols can be converted to cholesterol. In this study, we used RNA interference to modify the plant sterol profile to generate phytosterols that would negatively impact insect herbivores. Specifically, we knocked down the expression of Arabidopsis thaliana Δ8–Δ7-sterol isomerase gene (HYD1), responsible for the conversion of Δ8-sterols into Δ7-sterols. Silenced lines with > 95% transcript reduction showed drastically reduced sterol production and approximately half of the total sterols had a Δ8-configuration. Importantly, these sterol-modified lines exhibited normal growth compared to controls. In contract, the diamondback moth (Plutella xylostella) larvae reared on sterol-modified plants showed reduced growth and survival, while adults showed significantly decreased egg production. Sterol analysis of P. xylostella adults suggests these negative effects were likely a result of reduced cholesterol and the accumulation of Δ8-sterols. Finally, we modeled the effects of sterol-modified plants at the population level using our growth and reproductive data. We observed reduced population size and extended generation time after only two generations. Collectively, our results suggest that modifying plant sterols has potential for management of pest caterpillars, including the globally distributed P. xylostella. [ABSTRACT FROM AUTHOR]

The triterpene squalene is widely used in the food, cosmetics and pharmaceutical industries due to its antioxidant, antistatic and anti-carcinogenic properties. It is usually obtained from the liver of deep sea sharks, which are facing extinction. Alternative production organisms are marine protists from the family Thraustochytriaceae, which produce and store large quantities of various lipids. Squalene accumulation in thraustochytrids is complex, as it is an intermediate in sterol biosynthesis. Its conversion to squalene 2,3-epoxide is the first step in sterol synthesis and is heavily oxygen dependent. Hence, the oxygen supply during cultivation was investigated in our study. In shake flask cultivations, a reduced oxygen supply led to increased squalene and decreased sterol contents and yields. Oxygen-limited conditions were applied to bioreactor scale, where squalene accumulation and growth of Schizochytrium sp. S31 was determined in batch, fed-batch and continuous cultivation. The highest dry matter (32.03 g/L) was obtained during fed-batch cultivation, whereas batch cultivation yielded the highest biomass productivity (0.2 g/L*h−1). Squalene accumulation benefited from keeping the microorganisms in the growth phase. Therefore, the highest squalene content of 39.67 ± 1.34 mg/g was achieved by continuous cultivation (D = 0.025 h−1) and the highest squalene yield of 1131 mg/L during fed-batch cultivation. Volumetric and specific squalene productivity both reached maxima in the continuous cultivation at D = 0.025 h−1 (6.94 ± 0.27 mg/L*h−1 and 1.00 ± 0.03 mg/g*h−1, respectively). Thus, the choice of a suitable cultivation method under oxygen-limiting conditions depends heavily on the process requirements. Key points: • Measurements of respiratory activity and backscatter light of thraustochytrids • Oxygen limitation increased squalene accumulation in Schizochytrium sp. S31 • Comparison of different cultivation methods under oxygen-limiting conditions [ABSTRACT FROM AUTHOR]

Sterols are known for a plethora of 250 different structures. Between 5 and 10% of them usually occur with varying abundance ratios (~ four orders of magnitude) and total amounts (0.4–1000 mg/100 g oil) in samples. Yet, quantitative data are mostly restricted to the few major sterols which are available as reference standards. Here, we developed a gas chromatography with mass spectrometry method operated in selected ion monitoring mode (GC/MS-SIM) that enabled the quantitation of 30 (silylated) sterols although only ten were available as reference standards. This could be obtained by studying the full-scan mass spectra of these ten sterol standards and 20 additional sterols measured in seven oils. In the next step, sterols were assigned to different groups. Values for quantification were then selected on the premise that response factors were constant within a sterol group. The deviation of the response factors within one sterol group was frequently below ± 10% and otherwise about ± 11–12%. Using mean response factors for all sterols, the novel GC/MS-SIM quantification method was superior to GC/FID which was exemplarily applied to two oils. Between eight and 21 of the 30 studied sterols and pentacyclic triterpenols were detected and quantified in 18 vegetable oils and two vegetable fats. The much higher number of sterols that could be quantified resulted in higher sterol amounts and the method and data may be useful for food authentication. [ABSTRACT FROM AUTHOR]

In this research, phytochemical compounds and antioxidant capacity in camelina oil (CMO) were identified through chromatography and spectrophotometry methods and compared with canola (CNO) and sunflower (SNO) oils. The antioxidant potential of the oils was evaluated through DPPH scavenging and the β-carotene bleaching (BCB) methods. Furthermore, fatty acid profiles and some stability indices of the oil were measured. Finally, the correlation coefficients were assessed between the parameters. The results revealed that γ-tocopherol (659.02 mg α-T/kg) and β-sitosterol (2069.6 mg Chol/kg) were the main tocopherol and sterol in CMO, respectively. Tocopherol content in the oils studied did not differe significantly. The highest contents of sterols, carotenoids, and chlorophylls were found in CNO while the highest contents of phenols were found in CMO. CMO and CNO showed the highest DPPH scavenging (IC50 of 104.74 ± 1.85 and 123.33 ± 19.32 mg/mL, respectively) and BCB (IC50 of 78.41 ± 1.31 and 77.91 ± 5.37 mg/mL, respectively) activities. The peroxide and anisidine values (PV and AnV, respectively) of the oil were found to be in the order of SNO > CMO > CNO, while MUFA:PUFA ratio and the oxidative stability index (OSI) were CNO > CMO > SNO and CNO > SNO > CMO, respectively. The highest correlation of OSI was detected to be with sterol content (r: 0.920) and MUFA:PUFA ratio (r: 0.950) and the highest correlation of IC50 of antioxidant capacity assays was found to be with tocopherol content (r > 0.996). Overall, the correlation analyses indicated that in addition to fatty acid profile and level of oil unsaturation, the antioxidant content of cold-pressed oils should be considered to determine oil quality. [ABSTRACT FROM AUTHOR]

To study the influence of ecological growing conditions on the chemical composition of plants, supercritical carbon dioxide extraction is carried out of wild carrot samples, widespread in all regions of the world with a temperate climate (Daucus carota subsp. maritimus). Using the methods of gas-liquid chromatography and mass spectral analysis, volatile organic compounds, fatty acids, and phytosterols in the studied objects are determined in the extracts obtained. The dependence of the chemical composition of wild carrots on its growing conditions (temperature, precipitation, solar radiation, etc.) is shown. [ABSTRACT FROM AUTHOR]

Currently, special attention is paid to the study of the mechanisms of stress resistance of extremophile organisms that can survive in extreme conditions. Such organisms include lichens, which are symbiotic associations of fungi and algae and/or cyanobacteria. The high stress resistance of lichens is due to the presence of a wide range of biologically active metabolites, including sterols. It is known that lichens have a diverse and unique sterol composition, different from that of fungi and algae. Sterol-mediated biochemical mechanisms of stress resistance in lichens have not been fully studied and not systematized. Temperature stress is quite common for lichens, which often grow in unfavorable conditions. It is known that dry lichen thalli are able to withstand temperature changes over large ranges, while hydrated thalli are much more sensitive to unfavorable temperatures. In this work, stress-induced changes in respiratory activity and membrane stability index (MSI), as well as the sterol profile of hydrated lichen thalli, of Peltigera canina (L.) Willd. under the influence of elevated (+40°С) and low (–20°С) temperatures was investigated. It was shown that unfavorable temperatures caused a suppression of respiration rate and a decrease in the MSI of lichen thalli. Chromatomass spectrometric analysis showed the presence of P. canina ergosterol, dehydroergosterol, episterol, lichesterol, and fungisterol. Under the influence of both stress factors, there was a decrease in the level of ergosterol and an increase in the proportion of episterol. Under cold stress conditions, the proportion of dehydroergosterol also increased, the proportion of lichesterol decreased, and the relative content of the more saturated sterol fungisterol remained at the control level. It can be assumed that stress-induced changes in the sterol profile of lichens under low-temperature exposure create an optimal balance of sterols in membranes, which provides conditions for the deployment of a successful strategy leading to the adaptation of the lichen to the action of a stressor. [ABSTRACT FROM AUTHOR]

The proper structural flavonoids and essential sterols are preparation issues, and it requires a proper analytical method for proper measurements. The current article provides an advanced analysis of the bioactive compounds of Citrus paradisi cv. shamber (grapefruit) using advanced technologies. The fruit was subjected to analysis for major compounds like flavonoids and phytosterols under seasonal variation using liquid chromatography, quadrupole time-of-flight mass spectrometry (LC-Q-TOF–MS), and ultra-performance liquid chromatography (UPLC) techniques, where binding assays coupled with fingerprinting methods were applied for the first time. The flavonoids were detected by HPLC due to their higher precipitations and compared with other detection methods to validate the machine's efficiency. The efficacy was measured in all flavonoids in UHPLC. The highest value of flavonoids narirutin (92 mg/100 g FW), poncirin (11.2 mg/100 g FW), neohesperidin6 (15.6 mg/100 g FW), poncirin (11.2 mg/100 g FW), taxifolin and gallic acid (1.5 and 2.7 mg/100 g FW) were shown on December 1st, while the lowest range of flavonoids narirutin (43 mg/100 g FW The extract preparation issues were resolved in LC-Q-TOF–MS. Analysis of the bioactive compounds through LC-Q-TOF–MS, UPLC, and LC–MS was reported for nine flavonoids and six phytosterols were validated through fingerprinting analysis. The fingerprinting analysis reflects the quality of each sample, exhibiting the confirmation of all flavonoids and phytosterols. Results showed that juice is an excellent source of antioxidants, which were higher in December harvest fruits (mature fruits). It was established that the separation of bioactive compounds through advanced technology was safe where maximum contents of the compounds were reported and the proper maturity period played a significant role in the higher contents of the flavonoids and phytosterols. The new granulometric studies for particle size determination revealed the particle size of the sample as 0.75 µm in juice, followed by validation through intraday and interday analysis. All analyzed compounds showed a range of RSD of 2%, which exhibited the reliability of a process where all recoveries of total compounds were 97–100%. It was concluded that the LC-Q-TOF–MS and UF-HPLC techniques were efficient methods that could be extended to identify and screen other bioactive ingredients in other natural resources. [ABSTRACT FROM AUTHOR]

Steranes preserved in sedimentary rocks serve as molecular fossils, which are thought to record the expansion of eukaryote life through the Neoproterozoic Era (~ 1000-541 Ma). Scientists hypothesize that ancient C27 steranes originated from cholesterol, the major sterol produced by living red algae and animals. Similarly, C28 and C29 steranes are thought to be derived from the sterols of prehistoric fungi, green algae, and other microbial eukaryotes. However, recent work on annelid worms–an advanced group of eumetazoan animals–shows that they are also capable of producing C28 and C29 sterols. In this paper, we explore the evolutionary history of the 24-C sterol methyltransferase (smt) gene in animals, which is required to make C28+ sterols. We find evidence that the smt gene was vertically inherited through animals, suggesting early eumetazoans were capable of C28+ sterol synthesis. Our molecular clock of the animal smt gene demonstrates that its diversification coincides with the rise of C28 and C29 steranes in the Neoproterozoic. This study supports the hypothesis that early eumetazoans were capable of making C28+ sterols and that many animal lineages independently abandoned its biosynthesis around the end-Neoproterozoic, coinciding with the rise of abundant eukaryotic prey. Sterane molecular fossils are used to compliment evidence from the fossil record. Here, the authors use a molecular clock to explore the origins of the smt gene, tracing the loss of sterol synthesis to dietary shifts in animals at the end-Neoproterozoic. [ABSTRACT FROM AUTHOR]

Sarcandra glabra (Thunb.) Nakai is a perennial evergreen herb categorised within the Sarcandra Gardner genus under the Chloranthaceae family. Indigenous to tropical and subtropical regions of East Asia and India, this species is extensively distributed across China, particularly in the southern regions (Sichuan, Yunnan, and Jiangxi). In addition to its high ornamental value, S. glabra has a rich history of use in traditional Chinese medicine, evident through its empirical prescriptions for various ailments like pneumonia, dysentery, fractures, bruises, numbness, amenorrhea, rheumatism, and other diseases. Besides, modern pharmacological studies have revealed various biological activities, such as antitumour, anti-bacterial, anti-viral anti-inflammatory and immunomodulatory effects. The diverse chemical constituents of S. glabra have fascinated natural product researchers since the 1900s. To date, over 400 compounds including terpenoids, coumarins, lignans, flavonoids, sterols, anthraquinones, organic acids, and organic esters have been isolated and characterised, some featuring unprecedented structures. This review comprehensively examines the current understanding of S. glabra's phytochemistry and pharmacology, with emphasis on the chemistry and biosynthesis of its unique chemotaxonomic marker, the lindenane-type sesquiterpenoids. [ABSTRACT FROM AUTHOR]

Escin is a mixture of over 30 glycosylated triterpenoid (saponin) structures, extracted from the dried fruit of horse chestnuts. Escin is currently used as an anti-inflammatory, and has potential applications in the treatment of arthritis and cancer. Engineered yeast would enable production of specific bioactive components of escin at industrial scale, however many saponins have been shown to be toxic to yeast. Here we report that a Saccharomyces cerevisiae strain specifically lacking the sterol C-5 desaturase gene ERG3, exhibits striking enhanced tolerance to escin treatment. Transcriptome analyses, as well as pre-mixing of escin with sterols, support the hypothesis that escin interacts directly with ergosterol, but not as strongly with the altered sterols present in erg3Δ. A diverse range of saponins are of commercial interest, and this research highlights the value of screening lipidome mutants to identify appropriate hosts for engineering the industrial production of saponins. [ABSTRACT FROM AUTHOR]

Background: The phytochemical constitution and biological capabilities of Fragaria ananassa's calyx have not been extensively investigated before. Consequently, the research study pointed for characterization, isolation, and identification of the sterols and flavonoids as the major active constituents in the calyx of F. ananassa and evaluation for their impacts as free radicals scavenger and anti-inflammatory agent. Results: GC/MS investigation for the lipoidal constitutions of F. ananassa's calyx was performed to identify twenty-six compounds signifying 83.08%, as well as isolation of campesterol, stigmast-4-en-3-one, and β-sitosterol-d-glucoside by column chromatography technique. Additionally, quantification and identification of the flavonoids in the ethyl acetate extract was carried out by HPLC/DAD technique beside to isolation and structure elucidation of 5-hydroxy-7, 4′-dimethoxy flavone and Chrysin. The free radicals scavenging and anti-inflammatory activities of both non-polar and polar extracts have been tested against (DPPH and ABTS radicals) and (COX-1, COX-2, and 5-LOX enzymes), correspondingly. The results illustrated significant effects of the polar extract of F. ananassa calyx greater than non-polar one. The dynamic natures, binding interactions, and protein–ligand stabilities have also been investigated using the molecular dynamics (MD) simulation research. The MD simulation revealed that Chrysin's chromen ring was extended to catalytic position of COX-1 receptor, producing Pi-Pi T-shaped contact with Tyr 354 and Trp 356. In addition, Chrysin's chromen ring has formed a Pi-alkyl bond with Val 318 and Leu 321. However, due to the huge size of ꞵ-sitosterol-d-glucoside, the glycoside ring can form a hydrogen bond with Tyr 317. The cyclopentyl phenanthrene ring also possesses Pi-alkyl interactions with Ile 58, Leu 62, Val 85, Val 318, Tyr 324, Leu 326, Ala 496, and Leu 500. Conclusions: The findings of our study are crucial in establishing the molecular bases for Chrysin and ꞵ-sitosterol-d-glucoside action against anti-inflammatory targets and for developing more effective selective inhibitors. The discovery of the binding location for ATP can pave the door for development unique, structure-based approach for natural anti-inflammatory medications. [ABSTRACT FROM AUTHOR]

The alga Undaria pinnatifida is able to synthesize a great variety of bioactive metabolites of pharmaceutical and other industrial interest. However, this species has not yet been comprehensively studied in the Golfo San Jorge region (Chubut, Patagonia Argentina). Thus, in the present study, U. pinnatifida was collected at Golfo San Jorge, seasonally extracted and the chemical profile and biological activity evaluated by different techniques. The results showed that U. pinnatifida fundamentally biosynthesizes phenolic acids (caffeic and ferulic acids), flavonols and flavanol glycosides (quercetin, cacticin, quercitrin), carbohydrates, tannins, lipids, saponins, quinones, steroids, triterpenes and cardiotonic glycosides (of the k-strophanthoside, sciloriside, adynerin and convalatoxin types), with differences according to the season. The extracts also showed moderate antioxidant activity by the DPPH method and outstanding cytotoxic activity by the Artemia salina test. Based on the results obtained, U. pinnatifida can be considered as a potential source of bioactive molecules. Variations in the metabolites were observed throughout the seasons; particularly in the winter season, flavonoids were present in hexane and chloroform extracts, but not in methanol; tannins and other phenolic derivatives in the three winter extracts. This shows the importance of conducting seasonal studies to determine the best season for collection based on the metabolites to be studied. [ABSTRACT FROM AUTHOR]

Yarrowia lipolytica has found many biotechnological applications. The species has a number of regulatory mechanisms to maintain cellular homeostasis, enabling biomass growth in complex media. The aim of this study was to evaluate the use of Y. lipolytica yeast as a platform for the simultaneous management of several industrial by-products and the production of microbial lipids with application potential in the chemical and food industries. Batch cultures of KKP 379 strain were conducted in media with post-frying rapeseed oil (PFO) and a by-product of curd cheese production—acid whey. To evaluate the potential of Yarrowia as a nutraceutical, quantitative and qualitative analyses of microbial sterols were carried out along with an assessment of the biomass mineral composition. It was indicated that the composition and content of sterols varied depending on the phase of cell growth in batch culture. During culture in medium with 20% (v/v) whey and 50 g/L PFO, the cellular lipid content reached 39% (w/w). The highest amount of sterols per dry biomass (7.38 mg/g) and cellular lipids (21.08 mg/g) was recorded after 38 h of culture. The dominant was ergosterol 12.10 mg/g (57%). In addition, the composition of carbon and nitrogen sources in the medium affected the content of selected elements in biomass, indicating that substrate modification can be a tool for manipulating the composition of yeast cells. The results of the study showed that the selection of waste substrates is an important factor in regulation of the cellular lipid accumulation efficiency, as well as the content of certain sterols. [ABSTRACT FROM AUTHOR]

Effects of 1 M NaCl on the lipid profile of detergent-resistant membranes in chloroplasts and mitochondria of salt-accumulating halophyte plants of family Amaranthaceae, Salicornia perennans Willd. and Suaeda salsa (L.) Pall. were studied. The composition of lipids and fatty acids in detergent-resistant membranes differed from total lipids of chloroplast and mitochondrial membranes by the abundance of cerebrosides and sterols. Under the given salinity level, a manyfold increase in the relative content of cerebrosides was noted in the composition of detergent-resistant chloroplast membranes of S. perennans. A similar salinity-related increase in cerebroside content was detected in detergent-resistant mitochondrial membranes of S. salsa. The opposite effect was observed for sterols: their relative content decreased under the action of salt. The results indicate that the detergent-resistant membranes are involved in the interactions of chloroplasts and mitochondria in the cell response of halophytes to salinity. [ABSTRACT FROM AUTHOR]

Background: Bees provide essential pollination services for many food crops and are critical in supporting wild plant diversity. However, the dietary landscape of pollen food sources for social and solitary bees has changed because of agricultural intensification and habitat loss. For this reason, understanding the basic nutrient metabolism and meeting the nutritional needs of bees is becoming an urgent requirement for agriculture and conservation. We know that pollen is the principal source of dietary fat and sterols for pollinators, but a precise understanding of what the essential nutrients are and how much is needed is not yet clear. Sterols are key for producing the hormones that control development and may be present in cell membranes, where fatty-acid-containing species are important structural and signalling molecules (phospholipids) or to supply, store and distribute energy (glycerides). Aim of the review: In this critical review, we examine the current general understanding of sterol and lipid metabolism of social and solitary bees from a variety of literature sources and discuss implications for bee health. Key scientific concepts of review: We found that while eusocial bees are resilient to some dietary variation in sterol supply the scope for this is limited. The evidence of both de novo lipogenesis and a dietary need for particular fatty acids (FAs) shows that FA metabolism in insects is analogous to mammals but with distinct features. Bees rely on their dietary intake for essential sterols and lipids in a way that is dependent upon pollen availability. [ABSTRACT FROM AUTHOR]

Squalene is a widely distributed natural triterpene, as it is a key precursor in the biosynthesis of all sterols. It is a compound of high commercial value worldwide because it has nutritional, medicinal, pharmaceutical, and cosmetic applications, due to its different biological properties. The main source of extraction has been shark liver oil, which is currently unviable on a larger scale due to the impacts of overexploitation. Secondary sources are mainly vegetable oils, although a limited one, as they allow low productive yields. Due to the diversity of applications that squalene presents and its growing demand, there is an increasing interest in identifying sustainable sources of extraction. Wild species of thraustochytrids, which are heterotrophic protists, have been identified to have the highest squalene content compared to bacteria, yeasts, microalgae, and vegetable sources. Several studies have been carried out to identify the bioprocess conditions and regulation factors, such as the use of eustressors that promote an increase in the production of this triterpene; however, studies focused on optimizing their productive yields are still in its infancy. This review includes the current trends that also comprises the advances in genetic regulations in these microorganisms, with a view to identify the culture conditions that have been favorable in increasing the production of squalene, and the influences that both bioprocess conditions and applied regulation factors partake at a metabolic level. [ABSTRACT FROM AUTHOR]

Countercurrent chromatography (CCC) is a preparative instrumental method where both the mobile and stationary phases are liquids and which are predominantly used for the isolation of natural products. In this study, we widened the scope of CCC by using it as an instrumental method for the direct enrichment of the free sterol fraction from plant oils to which they contribute with ~ 1%. For the enrichment of sterols in a narrow band, we employed the so-called co-current CCC (ccCCC) mode in which both liquid phases of the solvent system (here: n-hexane/ethanol/methanol/water (34:11:12:2, v/v/v/v)) are moved at different flow rates in the same direction. Different from previous applications of ccCCC, the lower and predominant "stationary" phase (LPs) was pumped twice as fast as the mobile upper phase (UPm). This novel reversed ccCCC mode improved the performance but also required a higher demand of LPs compared to UPm. Therefore, the exact phase composition of UPm and LPs was determined by gas chromatography and Karl Fischer titration. This step enabled the direct preparation of LPs which considerably reduced the waste of solvents. Internal standards (phenyl-substituted fatty acid alkyl esters) were synthesised and utilised to frame the free sterol fraction. This approach allowed a fractionation of free sterols based on the UV signal and compensated run-to-run variations. The reversed ccCCC method was then applied to the sample preparation of five vegetable oils. In addition to free sterols, free tocochromanols (tocopherols, vitamin E) were also eluted in the same fraction as free sterols. [ABSTRACT FROM AUTHOR]

Upon DNA damage, cells activate the DNA damage response (DDR) to coordinate proliferation and DNA repair. Dietary, metabolic, and environmental inputs are emerging as modulators of how DNA surveillance and repair take place. Lipids hold potential to convey these cues, although little is known about how. We observed that lipid droplet (LD) number specifically increased in response to DNA breaks. Using Saccharomyces cerevisiae and cultured human cells, we show that the selective storage of sterols into these LD concomitantly stabilizes phosphatidylinositol‐4‐phosphate (PI(4)P) at the Golgi, where it binds the DDR kinase ATM. In turn, this titration attenuates the initial nuclear ATM‐driven response to DNA breaks, thus allowing processive repair. Furthermore, manipulating this loop impacts the kinetics of DNA damage signaling and repair in a predictable manner. Thus, our findings have major implications for tackling genetic instability pathologies through dietary and pharmacological interventions. Synopsis: How can metabolic and environmental cues modulate the DNA damage response (DDR)? Here, the master DDR kinase Tel1/ATM is found to bind phosphatidylinositol‐4‐phosphate (PI(4)P) at the Golgi, altering its availability in the nucleus and impacting the kinetics, intensity, and persistence of the response to DNA double‐strand breaks in yeast and human cells.Lipid droplets accumulate in response to DNA double‐strand breaksDNA break‐induced sterol storage into lipid droplets lowers their level at the endoplasmic reticulum (ER)Low ER sterol levels decrease OSBP1 activity, which stabilizes PI(4)P at the GolgiGolgi‐stabilized PI(4)P binds the DDR kinase Tel1/ATM, titrating it from the nucleus [ABSTRACT FROM AUTHOR]

Complex sphingolipids and sterols are coordinately involved in various cellular functions, e.g. the formation of lipid microdomains. Here we found that budding yeast exhibits resistance to an antifungal drug, aureobasidin A (AbA), an inhibitor of Aur1 catalyzing the synthesis of inositolphosphorylceramide, under impaired biosynthesis of ergosterol, which includes deletion of ERG6, ERG2, or ERG5 involved in the final stages of the ergosterol biosynthesis pathway or miconazole; however, these defects of ergosterol biosynthesis did not confer resistance against repression of expression of AUR1 by a tetracycline-regulatable promoter. The deletion of ERG6, which confers strong resistance to AbA, results in suppression of a reduction in complex sphingolipids and accumulation of ceramides on AbA treatment, indicating that the deletion reduces the effectiveness of AbA against in vivo Aur1 activity. Previously, we reported that a similar effect to AbA sensitivity was observed when PDR16 or PDR17 was overexpressed. It was found that the effect of the impaired biosynthesis of ergosterol on the AbA sensitivity is completely abolished on deletion of PDR16. In addition, an increase in the expression level of Pdr16 was observed on the deletion of ERG6. These results suggested that abnormal ergosterol biosynthesis confers resistance to AbA in a PDR16-dependent manner, implying a novel functional relationship between complex sphingolipids and ergosterol. [ABSTRACT FROM AUTHOR]

Edible insects are increasingly gaining popularity as research reveals multiple benefits. However, the rediscovery of natural products from insects as medicinal agents has received limited attention. This study aimed at evaluating the diversity of sterols in extracts of nine edible insects and potential antibacterial activities. Dichloromethane extracts of these insects were analyzed using gas chromatography–mass spectrometry to identify important sterols, followed by evaluation of their anti-bacterial activities. Nineteen sterols were identified with the highest recorded in African fruit beetle [Pachnoda sinuata (47.37%)], crickets [Gryllus bimaculatus (36.84%) and Scapsipedus icipe (31.58%)]. Cholesterol was the most prevalent, except in black soldier fly (Hermetia illucens). Bioactivity revealed S. icipe as the most potent extract against Escherichia coli and Bacillus subtilis whereas G. bimaculatus was highest against Methicillin-susceptible Staphylococcus aureus 25923. These findings unravels the diversity of sterols in edible insects and their possible application in food, pharmaceutical and cosmetic industries. [ABSTRACT FROM AUTHOR]

Several tree legume species' (Caesalpinia pulcherrima, Enterolobium cyclocarpum, Leucaena leucocephala, Pithecellobium dulce, Samanea saman, Sesbania grandiflora and Tamarindus indica) mature seeds were investigated for their lipophilic fraction profile. The oil yield ranged 2.1–14.9%. Linoleic acid was generally dominant (31.86–62.28%), followed by oleic (14.95–33.84%) and palmitic (7.21–17.54%) acid. Total tocochromanol content ranged 41.7–326.0 mg 100 g−1 oil. Tocopherols (Ts), especially α-T (23.0–197.8 mg 100 g−1 oil) and γ-T (7.3–264.0 mg 100 g−1 oil), dominated, and the seeds either did not contain tocotrienols or the content was negligible. Total carotenoid content ranged 2.1–11.8 mg 100 g−1 oil. Only C. pulcherrima and P. dulce contained squalene. The total sterol content ranged 94–1810 mg 100 g−1 oil, and the seeds contained mostly β-sitosterol, Δ5-stigmasterol, campesterol and cycloartenol. Although the oil yield is too low for commercial oil production, some of the studied species (C. pulcherrima, L. leucocephala and T. indica) could be considered as bioactive compound-rich oil sources. [ABSTRACT FROM AUTHOR]

Eukaryotes produce highly modified sterols, including cholesterol, essential to eukaryotic physiology. Although few bacterial species are known to produce sterols, de novo production of cholesterol or other complex sterols in bacteria has not been reported. Here, we show that the marine myxobacterium Enhygromyxa salina produces cholesterol and provide evidence for further downstream modifications. Through bioinformatic analysis we identify a putative cholesterol biosynthesis pathway in E. salina largely homologous to the eukaryotic pathway. However, experimental evidence indicates that complete demethylation at C-4 occurs through unique bacterial proteins, distinguishing bacterial and eukaryotic cholesterol biosynthesis. Additionally, proteins from the cyanobacterium Calothrix sp. NIES-4105 are also capable of fully demethylating sterols at the C-4 position, suggesting complex sterol biosynthesis may be found in other bacterial phyla. Our results reveal an unappreciated complexity in bacterial sterol production that rivals eukaryotes and highlight the complicated evolutionary relationship between sterol biosynthesis in the bacterial and eukaryotic domains. Production of highly modified sterols, such as cholesterol, is essential to eukaryotic physiology but has not been yet reported for bacteria. Here, Lee et al. show that a marine myxobacterium produces cholesterol, and provide evidence for further downstream modifications in this and other bacterial species. [ABSTRACT FROM AUTHOR]

Sterane molecular fossils are broadly interpreted as eukaryotic biomarkers, although diverse bacteria also produce sterols. Steranes with side-chain methylations can act as more specific biomarkers if their sterol precursors are limited to particular eukaryotes and are absent in bacteria. One such sterane, 24-isopropylcholestane, has been attributed to demosponges and potentially represents the earliest evidence for animals on Earth, but enzymes that methylate sterols to give the 24-isopropyl side-chain remain undiscovered. Here, we show that sterol methyltransferases from both sponges and yet-uncultured bacteria function in vitro and identify three methyltransferases from symbiotic bacteria each capable of sequential methylations resulting in the 24-isopropyl sterol side-chain. We demonstrate that bacteria have the genomic capacity to synthesize side-chain alkylated sterols, and that bacterial symbionts may contribute to 24-isopropyl sterol biosynthesis in demosponges. Together, our results suggest bacteria should not be dismissed as potential contributing sources of side-chain alkylated sterane biomarkers in the rock record. Sterane molecular fossils with side-chain methylations have not been reported in the bacterial domain. One such sterane, 24-isopropylcholestane, has been attributed to ancient sponges, potentially representing the earliest evidence for animals on Earth. This study demonstrates that symbiotic bacteria are capable of producing the 24-isopropyl sterol side-chain, suggesting that bacteria should not be dismissed as sources of these biomarkers in the rock record. [ABSTRACT FROM AUTHOR]

The cell lines of Siberian larch (Larix sibirica Ledeb.), possessing different embryogenic potential, were studied. Qualitative and quantitative content of sterol components was comparatively analyzed in their tissues with the help of gas chromatography-mass spectrometry. Significant differences in these parameters were found between both groups of the lines in fractions of free sterols and their esters. In addition to sterol compounds, squalen, which is a triterpenic intermediate in sterol biosynthesis, was revealed. Of free sterols, β-sitosterol, campesterol, isofucosterol, and stigmasterol dominated in the embryogenic lines, while β-sitosterol, campesterol, and stigmasterol in nonembryogenic ones. The campesterol concentration was 1.3–1.9 times higher in the embryogenic than nonembryogenic lines. Since campesterol is a precursor of brassinosteroids, it is likely that its level is high due to an embryogenic state of these cell lines. Only the embryogenic lines contained appreciable amounts of isofucosterol. The fraction of sterol esters exhibited wider component diversity in the nonembryogenic than the embryogenic lines. In all the cell lines, among the identified sterol esters, the substances without double bonds, bearing, as a structural fragment, a sterane core—perhydrocyclopenta[a]phenanthrene—were the most abundant. Their content ranged from 52 to 71% of the total amount of sterol esters. The revealed differences in the compositions of sterols and their esters, between the L. sibirica cell lines with different embryogenic potential, witness to the considerable rearrangements in sterol metabolism in the course of embryogenesis. The line-specific differences may indicate the involvement of these metabolites in formation of embryos. [ABSTRACT FROM AUTHOR]

Lipids may serve as energy reserves to support coral calcification, allow acclimation to higher temperatures, and are implicated in the control of CaCO3 precipitation. Here, we report the lipid composition of the soft tissues (including host and symbionts) of 7 massive Porites spp. coral colonies (4 × P. lutea and 3 × P. murrayensis), which were cultured under different pCO2 concentrations (180, 260, 400 and 750 µatm) and at two temperatures (25 ℃ and 28 ℃), below the thermal stress threshold. We report the fatty acid methyl esters (FAME), free fatty acid (FFA) to total fatty acid content, sterol and wax ester profiles, and identify two ketones (n-alkanone) and three long chain aldehyde (n-alkanal) derivatives. Increasing seawater temperature significantly increases the contributions of FFAs to the total lipids, of C18:2 and C20:0 to the total FFA pool, of C14:0 to total FAME, and of campesterol to total sterol. The temperature increase also reduces the contributions of unusual fatty acid derivatives to total lipids, of C14:0, C15:0, C16:0 and C17:0 saturated free fatty acids to total FFAs, and of C16:0 FA to total FAME. Fatty acids are implicated in the control of membrane structure fluidity and the observed changes may promote acclimation and thermostability as temperature varies. Seawater pCO2 has no significant effect on the composition of tissue lipids with the exception that the contribution of C14:0 FA to total lipid content is significantly lower at 180 µatm compared to 260 and 750 µatm. Decreased contribution of total sterols and unusual fatty acid derivatives and increased contribution of total FFAs to total lipids are observed in the fastest calcifying coral (a P. lutea specimen) compared to the other corals, under all pCO2 and temperature conditions. Although a rapid calcifier this genotype has been shown previously to exhibit pronounced abnormal changes in skeletal morphology in response to decreased seawater pCO2. Variations in tissue lipid composition between coral genotypes may influence their resilience to future climate change. [ABSTRACT FROM AUTHOR]

To qualitatively and quantitatively distinguish the boundaries of commercial strong-, mellow- and light- fragrant rapeseed oils in Chinese market, 24 commercial rapeseed oils were symmetrically analyzed to characterize their profiles of physical/chemical components, key aroma compounds, and nutrients and their concentrations. Results showed that strong- fragrant flavor rapeseed oil had highest AV of 0.25–1.73 mg/g, PV of 0.50–3.37 mmol/kg, Lovibond red reading of > 2.0, total tocopherol of > 505 mg/kg, total sterols of over 4445 mg/kg, and average CoQ10 contents of > 204 mg/kg, followed by mellow- and light- fragrant flavor rapeseed oils. Strong- fragrant rapeseed oil held the highest roasted odor and nutty flavor, while mellow- fragrant rapeseed oil had more acceptable taste with highest soft and spicy taste values. The typical volatile compounds such as hexanal, dimethyl sulfoxide and 5-hexenenitrile could be used to quantitatively and qualitatively distinguish three types of rapeseed oils using PCA Cluster analysis. These findings would provide a reference to multi-dimensionally distinguish and select the favorable rapeseed oil for consumers from these types of commercial fragrant rapeseed oils. [ABSTRACT FROM AUTHOR]

The northern South China Sea (NSCS) is significantly influenced by the Kuroshio intrusion and the coastal currents. Our knowledge on the roles of both currents on phytoplankton spatial variations is still inadequate. Here, we investigated the concentrations of phytoplankton biomarkers and their proportions in surface suspended particles from 47 sites of the NSCS during summer of 2017 and 2019. Brassicasterol/epi-brassicasterol, dinosterol, and C37 alkenones were used as proxies of biomass for diatoms, dinoflagellates, and haptophytes, respectively, and their sum indicating total phytoplankton biomass. A three end-member mixing model was applied to quantitatively assess the influence extent of the Kuroshio intrusion and the coastal currents. Our results showed that the Kuroshio intrusion and the coastal currents contributed equally to the overall surface water masses in the study area; however, the two currents had distinct effects on the spatial distribution of phytoplankton. For phytoplankton biomass, the eutrophic coastal currents were likely to be the main controlling factors, while the impact of the Kuroshio intrusion was weak and stimulated significant increases in phytoplankton biomass only at certain boundary sites. For phytoplankton community structures, the Kuroshio and its intrusion were the main factors, resulting in an increase in the proportions of dinoflagellates and haptophytes. The proportion of diatoms slightly increased due to the influence of the coastal currents. Our study quantifies the effects of the Kuroshio and the coastal currents on phytoplankton in the NSCS in terms of hydrological parameters, providing an important basis for the understanding of ecological functions and biogeochemical cycles in marginal sea-open ocean boundary regions. [ABSTRACT FROM AUTHOR]

Fourteen wild (W) and cultivated (C) seed samples from nine Onosma species were collected in various climate zones and were analyzed for contents of neutral lipids (NL) and polyunsaturated fatty acids (PUFAs). The species O. tanaitica (C and W), O. rigidum (W), and O. simplicissima (W) had the richest contents of NL (from 17.5 to 20.5%) and PUFAs (from 74 to 80%). The compositions of NL, polar lipids, and several lipophilic constituents of seeds of wild O. simplicissima growing in the Republic of Bashkortostan were determined. Six NL classes and the contents and compositions of tocopherols (18.2 mg/100 g of seeds) and sterols (77.5 mg/100 g) were identified in seeds of the species. The main constituent of the tocopherols was γ-tocopherol; of the sterols, ∆-5-avenasterol. [ABSTRACT FROM AUTHOR]

Estuaries are ecosystems that have been changed by climatic and anthropogenic events, and subtropical estuaries located in the Southern Hemisphere are important examples of historical human occupation, land use and recent degradation. This study aims to assess whether climatic and anthropogenic events promoted the variability of sedimentary organic matter (OM) in two estuarine systems, the Paranaguá Estuarine System and Guaratuba Bay, Brazil, using geochemical multiproxies. In this approach, bulk elementary and isotopic properties were integrated with specific molecular biomarkers (n-alkanes, n-alkanol and sterols) detected in the sedimentary OM from sediment cores. Our results showed a predominance of terrigenous OM in both estuarine systems over the last century. However, sterols proved to be a more robust proxy for indicating changes in the autochthonous input of sedimentary OM, especially in the core top sections. Based on the molecular biomarkers and total annual precipitation data, the climatic effects of periodic events (e.g., El Niño–Southern Oscillation) that occurred during the last century did not seem to have imposed noticeable changes in the sedimentary OM over the period covered by the cores (e.g., between 1912 and 2010 for the Paranaguá Estuarine System). Instead, OM variations may respond to changes in the drainage basin or to specific local human activities. Plant extraction in the drainage basin was recorded in Guaratuba Bay before the 1960s, and the intensification of human occupation after the 1950s was recorded in the Paranaguá Estuarine System. The multiproxy approach demonstrated that local environmental changes related to regional anthropogenic events in the adjacent drainage basin of estuaries may be considered for identifying human impacts in coastal zones. [ABSTRACT FROM AUTHOR]

The composition of lipids isolated from the middle leaves and juice of 7-year-old Aloe arborescens Mill. and the inhibitory efficiency of lipids from the leaves of this aloe species were studied. The phospholipid fractions were divided by means of TLC method. The quantitative ratio of phospholipid fractions was analyzed spectrophotometrically. The most essential differences in the composition of phospholipids (PL) from aloe leaves and juice were revealed for the ratio of the more poorly oxidizable fractions. The more low relative content of PL in the total lipid composition from aloe leaves compared with than in lipids from juice result in 16% diminution in the molar ratio [sterols]/[PL] in the composition of lipids from aloe juice because shares of sterols are the same in lipids from aloe leaves and juice. Lipids from aloe leaves are shown to characterize the high inhibitory efficiency that is demonstrated by model of the low temperature methyl oleate autoxidation in a thin layer. Using UV spectroscopy and the mathematic processing of UV spectra by Gauss method the presence of biologically active substances contained in lipids was analyzed. There are only flavonoids in the chloroform solution of lipids from aloe juice, while in lipids from aloe leaves, in addition to flavonoids, carotenoids is also found at a low quantity. [ABSTRACT FROM AUTHOR]

Aspergillus penicillioides may be both xerophilic and halophilic. To study whether there is a difference in the mechanisms of adaptation to low water activity and high NaCl concentration the composition of osmolytes and lipids was analysed during growth on two media with 2 M NaCl or 4 M glycerol. Glycerol was the predominant osmolyte of the fungus mycelium grown on both media at all growth stages. On the medium with glycerol, the fungus accumulated twice as much glycerol as on the medium with salt. The proportion of erythritol, arabitol and mannitol was significantly higher on a medium with salt (up to 30% of the total). It was first shown that phosphatidic acids, along with sterols, were the predominant membrane lipids, while phosphatidylcholines and phosphatidylethanolamines, typical for most fungi, were minor. The general pattern of changes in the membrane lipid composition on both media during growth was the increase in the proportions of sterols and unidentified lipid X1 along with the decrease of phosphatidic acids and cardiolipins, but the changes on the salt medium were more pronounced. The degree of phospholipid unsaturation decreased only on the medium with glycerol. The results obtained show main patterns and differences in the mechanisms of adaptation of fungus to low water activity and high salt concentration. [ABSTRACT FROM AUTHOR]

Though cholesterol is the most prevalent and essential sterol in mammalian cellular membranes, its precursors, post-synthesis cholesterol products, as well as its oxidized derivatives play many other important physiological roles. Using a non-invasive in situ technique, time-resolved small angle neutron scattering, we report on the rate of membrane desorption and corresponding activation energy for this process for a series of sterol precursors and post-synthesis cholesterol products that vary from cholesterol by the number and position of double bonds in B ring of cholesterol's steroid core. In addition, we report on sterols that have oxidation modifications in ring A and ring B of the steroid core. We find that sterols that differ in position or the number of double bonds in ring B have similar time and energy characteristics, while oxysterols have faster transfer rates and lower activation energies than cholesterol in a manner generally consistent with known sterol characteristics, like Log P, the n-octanol/water partitioning coefficient. We find, however, that membrane/water partitioning which is dependent on lipid-sterol interactions is a better predictor, shown by the correlation of the sterols' tilt modulus with both the desorption rates and activation energy. [ABSTRACT FROM AUTHOR]

Laetiporus species are brown rot fungi belonging to the order Polyporales in the division Basidiomycota. These species produce a variety of metabolites and provide a great source of natural material for the screening of medicinally active natural products or their derivatives. This review summarizes the research progress on bioactive metabolites of Laetiporus species up to April 2022, including biological macromolecules, for instance, polysaccharides and lectins, as well as 80 reported small molecule chemical components (15 sterols, 29 triterpenes, 10 sesquiterpenes, 5 polyenes, 10 volatile compounds, and 11 other compounds). These metabolites exhibit antimicrobial, anticancer, antioxidant, hepatoprotective, anti-inflammatory, and antidiabetic activities. Genome mining predicted 23 terpene synthases, 7 polyketide synthases, and 9 non-ribosomal peptide synthases involved in bioactive metabolites biosynthesis, which were analyzed by antiSMASH in L. sulphureus genome. This review will provide a basis for the biosynthesis of active components in Laetiporus species and a reference for the research of medical precursors. Key points: • The mini-review summarized 80 secondary metabolites of Laetiporus spp. • The main pharmacological activities of Laetiporus spp. were summarized. • Biosynthetic genes of terpenoids, polyketides, and non-ribosomal peptides were also summarized. [ABSTRACT FROM AUTHOR]

We compared oxidative and osmotic stress-induced changes in sterol content in plasma membranes and tonoplasts isolated from stored beet (Betavulgaris L.) roots. The most significant differences between the membranes under all studied stresses were observed in the cholesterol content: it decreased in the plasmalemma, but increased 4-6 times in the tonoplast. Similar changes were observed for other sterols, but in different ways under different types of stress. Particularly noticeable differences were noted under hyperosmotic stress. The increase in the content of sterols was much more pronounced in the vacuolar membrane compared to the plasmalemma. This observation allows us to conclude that tonoplast plays a more significant role in protection of the plant cell from stress compared to plasmalemma. [ABSTRACT FROM AUTHOR]

Fecal pollution in surface waters is a major threat to recreational and drinking water resources, with Escherichia coli being a primary concern. The best way to mitigate fecal pollutant loading is to identify the sources and tailor remediation strategies to reduce loading. Tracking E. coli back to its source is notoriously difficult in a mixed-use watershed where input from humans, wildlife, and livestock all contribute to E. coli loading. One proposed tracking method for E. coli contamination is the use of fecal sterols and sterol ratios. This study uses fecal sterol data published globally to assess how well sterol compositions for different species clusters along with the effectiveness of sterol ratios as tracking tools. Hierarchical cluster analysis produces stronger clusters based on sterol ratios than raw sterol concentration, but the global dataset results in clustering of the same species in different levels. The accuracy of the sterol ratios was also compared to understand the rate of false negatives and false positive assignments. Overall, these ratios did not have a high success rate for determining the correct source, which was also reflected in the poor clustering trends observed. Establishing local end-member sterol profiles is essential when using sterol signatures to unravel fecal loading. [ABSTRACT FROM AUTHOR]

Characterization and further development of underutilized/underexploited indigenous tropical seed oils are essential to supplement both nutritional and industrial needs of an ever-increasing African (and global) population. Before now and to our best knowledge, the previous research involved Canarium schweinfurthii Engl. fruit specific to Nigeria appear to have been more on the evaluation of seed, pulp, and essential oils (from the seed), but much less on the pulp oil. To supplement existing information, this current work has aimed to biochemically characterize the Soxhlet-extracted pulp oil of C. schweinfurthii fruit gathered from a community situated in the South-east of Nigeria. Specifically, the biochemical characterization comprised the determinations of proximate compositions, lipid peroxidation, fatty acid profile, as well as carotenoids, sterols, and tocopherols. Processing the fruit sample to pulp oil involved, among others, oven-drying, and grinding, prior to the Soxhlet extraction. Results of proximate components of C. schweinfurthii pulp oil showed the following trend: crude fat content (~ 49.32%) > carbohydrates (~ 37.93%) > moisture content (~ 8.62%) > ash content (~ 3.74%) > crude protein content (~ 0.39%) values. The lipid peroxidation attributes comprised acid (~ 23.60 mg KOH/g), peroxide (~ 33.91 mEq. O2/kg), iodine (~ 58.3 g/100 g), and saponification (~ 138.21 mg KOH/g) values. In addition to the free (~ 13.8%), saturated (~ 9.74%), and unsaturated (~ 90.26%) fatty acids, a total of fifteen (15) fatty acid methyl esters (FAMEs) spectral peaks were found, from caprylic acid (C8:0) to lignoceric acid (C24:0). Total tocopherol concentration amounted to ~ 73 mg/100 g, which comprised α, β, γ-tocopherol, and δ-tocotrienol, with fair concentrations of carotenoids and sterols. Overall, the C. schweinfurthii pulp oil—biochemically competitive with a high concentration of unsaturated fatty acid, tocopherol, and sterol, suggests strong industrial promise. [ABSTRACT FROM AUTHOR]

Antarctic krill (Euphausia superba) are a circumpolar species with an omnivorous diet. Knowledge of krill diet within different regions will help predict how environmental change may impact local krill populations. Krill from the Atlantic, Indian, and Pacific sectors of the Southern Ocean were compared. The total lipid, lipid class, neutral lipid fraction fatty acid and sterol content and composition of whole krill, their digestive glands, and stomachs during the late-summer were examined. Indian sector krill had a distinctly different dietary lipid pattern to Atlantic and Pacific sector krill based on their fatty acid profiles (p < 0.001). Indian sector whole krill had higher phospholipids (55.0 ± 8.9%, % total lipids) compared to Pacific (45.9 ± 3.6%) and Atlantic sector whole krill (43.7 ± 8.2%) but showed lower phospholipid levels in their digestive glands (29.4 ± 8.5%, 52.5 ± 5.7%, 52.5 ± 5.9%, respectively). Indian sector krill had a more copepod and diatomaceous diet (higher levels of 16:1n-7c, 14:0 and 20:1 and 22:1 isomers), with less flagellate input (lower 18:4n−3, 21:5n−3 and 18:3n−6) than other regions. Krill from one site in the Indian sector had particularly high 22:6n-3 levels. Indian sector krill had lower cholesterol levels in their stomachs (52.5 ± 14.1%, as % total sterols) than Pacific and Atlantic sector krill stomachs (62.8 ± 1.9% and 60.9 ± 4.9%, respectively). This study details the regional differences in late-summer krill diet by assessing the lipid, neutral lipid fraction fatty acid and sterol content and composition of different tissue types. [ABSTRACT FROM AUTHOR]

The yeast Saccharomyces cerevisiae is powerful for studying human G protein-coupled receptors as they can be coupled to its mating pathway. However, some receptors, including the mu opioid receptor, are non-functional, which may be due to the presence of the fungal sterol ergosterol instead of cholesterol. Here we engineer yeast to produce cholesterol and introduce diverse mu, delta, and kappa opioid receptors to create sensitive opioid biosensors that recapitulate agonist binding profiles and antagonist inhibition. Additionally, human mu opioid receptor variants, including those with clinical relevance, largely display expected phenotypes. By testing mu opioid receptor-based biosensors with systematically adjusted cholesterol biosynthetic intermediates, we relate sterol profiles to biosensor sensitivity. Finally, we apply sterol-modified backgrounds to other human receptors revealing sterol influence in SSTR5, 5-HTR4, FPR1, and NPY1R signaling. This work provides a platform for generating human G protein-coupled receptor-based biosensors, facilitating receptor deorphanization and high-throughput screening of receptors and effectors. The yeast Saccharomyces cerevisiae is powerful for studying human G protein-coupled receptors as they can be coupled to its mating pathway. Here the authors engineer baker's yeast to produce human sterols and show that vertebrate G protein coupled receptors are more sensitive in this membrane environment. [ABSTRACT FROM AUTHOR]

We evaluated the leishmanicidal activity of commercially available 5α-cholest-7-en-3β-ol [5α-chol], (+)-4-cholesten-3-one [(+)-4-chol] and the equimolar mixture of the two of them in promastigotes and amastigotes of two different strains of Leishmania mexicana (LCL) and (DCL). The leishmanicidal effectiveness of these sterols was determined by promastigote growth-kinetic experiments and promastigote viability using the propidium iodide staining procedure. The proliferation test was performed using the CFSE (5-Carboxyfluorescein N-succinimidyl ester) staining of parasites at different time points. To determine the leishmanicidal effectiveness of these sterols in amastigotes, we evaluated parasite killing inside of macrophages at different time points. The trypan blue exclusion test was used to determine cytotoxicity of sterols in uninfected macrophages. We included in all experiments a control group of parasites treated with 2% DMSO (Dimethyl Sulfoxide) and another one treated with the reference drug sodium stibogluconate (Sb). Our results showed that the equimolar mixture at 2000 times lower concentration presented similar leishmanicidal activity as Sb. This mixture was similarly effective at 100 times lower concentration than individual sterols tested separately indicating the existence of a synergistic effect against LCL and DCL parasites. The therapeutic index of the equimolar mixture was 10,000—16,000 times higher than the one recorded by Sb and was not cytotoxic to macrophages. Therefore, the equimolar mixture of 5α-Chol and (+)-4-chol may represent a potential alternative for the treatment of cutaneous leishmaniasis. [ABSTRACT FROM AUTHOR]