Factors Affecting Shellfish Quality in Terms of Faecal Contamination at Blakeney Point, East Anglia, UK

Relatively high E. coli and Faecal Streptococci (FS) numbers have been reported in the waters surrounding Blakeney Point, East Anglia, UK, an area containing significant shellfishery industries including mussels and cockles, despite the implementation of development works aimed at reducing residual contamination problems. The aim of this study was to evaluate the potential of using bacterial analyses and sterol profiling to assess the current levels and source of faecal pollution at Blakeney Point. No evidence of significant human faecal contamination of water in and around Blakeney Point could be found using either traditional microbiological analyses or sterol profile analysis. The presence of significant quantities of sitosterol, however, suggests that faecal contamination of water from birds does occur but at the concentration detected would not affect water quality. Analysis of cockles and mussels taken from the area show that negligible levels of coprostanol were present, confirming that faecal pollution was not causing any contamination issues. Apart from cholesterol, brassicasterol, an algal biomarker, as expected was dominant in shellfish flesh. The results confirm that current water treatment processes are successful in ensuring water quality at Blakeney Point and that a combination of microbial testing with sterol profile analysis confirmed that low microbial concentrations of faecal contaminants present in and around Blakeney Point most probably originate from migratory and/or resident bird species.

Severe Genotype, Pancreatic Insufficiency and Low Dose of Pancreatic Enzymes Associate with Abnormal Serum Sterol Profile in Cystic Fibrosis

Background: Several factors could lead to lipid disturbances observed in cystic fibrosis (CF). This study aimed to assess sterol homeostasis in CF and define potential exogenous and endogenous determinants of lipid dysregulation. Methods: The study involved 55 CF patients and 45 healthy subjects (HS). Sterol concentrations (μg/dL) were measured by gas chromatography/mass spectrometry. CF was characterised by lung function, pancreatic status, liver disease and diabetes coexistence, Pseudomonas aeruginosa colonisation and BMI. CFTR genotypes were classified as severe or other. Results: Campesterol and β-sitosterol concentrations were lower (p = 0.0028 and p < 0.0001, respectively) and lathosterol levels (reflecting endogenous cholesterol biosynthesis) were higher (p = 0.0016) in CF patients than in HS. Campesterol and β-sitosterol concentrations were lower in patients with a severe CFTR genotype, pancreatic insufficiency and lower pancreatic enzyme dose (lipase units/gram of fat). In multiple regression analyses, β-sitosterol and campesterol concentrations were predicted by genotype and pancreatic insufficiency, whereas cholesterol and its fractions were predicted by phytosterol concentrations, age, dose of pancreatic enzymes, nutritional status and genotype. Conclusions: Independent determinants of lipid status suggest that malabsorption and pancreatic enzyme supplementation play a significant role in sterol abnormalities. The measurement of campesterol and β-sitosterol concentrations in CF patients may serve for the assessment of the effectiveness of pancreatic enzyme replacement therapy and/or compliance, but further research is required.

Sterol Composition of Sponges, Cnidarians, Arthropods, Mollusks, and Echinoderms from the Deep Northwest Atlantic: A Comparison with Shallow Coastal Gulf of Mexico

Triterpenoid biosynthesis is generally anaerobic in bacteria and aerobic in Eukarya. The major class of triterpenoids in bacteria, the hopanoids, is different to that in Eukarya, the lanostanoids, and their 4,4,14-demethylated derivatives, sterols. In the deep sea, the prokaryotic contribution to primary productivity has been suggested to be higher because local environmental conditions prevent classic photosynthetic processes from occurring. Sterols have been used as trophic biomarkers because primary producers have different compositions, and they are incorporated in primary consumer tissues. In the present study, we inferred food supply to deep sea, sponges, cnidarians, mollusks, crustaceans, and echinoderms from euphotic zone production which is driven by phytoplankton eukaryotic autotrophy. Sterol composition was obtained by gas chromatography and mass spectrometry. Moreover, we compared the sterol composition of three phyla (i.e., Porifera, Cnidaria, and Echinodermata) collected between a deep and cold-water region and a shallow tropical area. We hypothesized that the sterol composition of shallow tropical benthic organisms would better reflect their photoautotrophic sources independently of the taxonomy. Shallow tropical sponges and cnidarians from environments showed plant and zooxanthellae sterols in their tissues, while their deep-sea counterparts showed phytoplankton and zooplankton sterols. In contrast, echinoids, a class of echinoderms, the most complex phylum along with hemichordates and chordates (deuterostomes), did not show significant differences in their sterol profile, suggesting that cholesterol synthesis is present in deuterostomes other than chordates.

Fatty Acid and Sterol Profile of Nutmeg (Myristica fragrans) and Star Anise (Illicium verum) Extracted Using Three Different Methods

Nutmeg (Myristica fragrans) and star anise (Illicium verum) are popular spices worldwide originally from South East part of Asia. In addition to as food condiment, they have been used extensively in traditional medicine and lately as a subject of research in the field of pharmacology and medical sciences. Most research has been done on the subject of essential oils, especially for star anise, while data on seed oil properties are much scarcer. The main problem in the oil extraction of nutmeg is the hardness of the nut, while, for star anise seed, it is relatively low oil yield (around 10%). This presents a significant problem for screw press production and demands different methods of extraction for better oil yield and quality. The aim of this research was to compare three different methods of oil extraction with n-hexane agitation-assisted extraction (AAE), Soxhlet extraction (SE), and accelerated solvent extraction (ASE) at 25 and 100 °C and to compare the processes on the basis of invested time, oil yield, and fatty acid and sterol profile of the oils. The determination of fatty acid composition was carried out by GC–flame ionization detection (FID) analysis of fatty acid methyl esters, while the sterol composition was determined with GC–MS. The highest yield of oil was obtained using the Soxhlet method, while the best results combining time and yield were obtained with the ASE method at 100 °C. The main fatty acid in star anise seed oil was lauric acid (average 62.30%) with significant differences across extraction methods (p < 0.05), while myristic acid (average 75.69%) was the most abundant in all samples of nutmeg oil. The main sterol in all samples was β-sitosterol.

Are Sterols Useful for the Identification of Sources of Faecal Contamination in Shellfish? A Case Study

This work aimed to identify the major source(s) of faecal pollution impacting Salcott Creek oyster fisheries in the UK through the examination of the sterol profiles. The concentration of the major sewage biomarker, coprostanol, in water overlying the oysters varied between 0.01 µg L−1 and 1.20 µg L−1. The coprostanol/epicoprostanol ratio ranged from 1.32 (September) to 33.25 (February), suggesting that human sewage represents the key input of faecal material into the estuary. However, a correlation between the sterol profile of water above the oysters with that of water that enters from Tiptree Sewage Treatment Works (r = 0.82), and a sample from a site (Quinces Corner) observed to have a high population of Brent geese (r = 0.82), suggests that both sources contribute to the faecal pollution affecting the oysters. In identifying these key faecal inputs, sterol profiling has allowed targeted management practices to be employed to ensure that oyster quality is optimised.

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

BackgroundPatients 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.MethodsBeside 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).ResultsPI-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.ConclusionsA 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.

The role of sterols in plant response to abiotic stress

Sterols are integral components of the membrane lipid bilayer and they are involved in many processes occurring in plants, ranging from regulation of growth and development to stress resistance. Maintenance of membrane homeostasis represents one of the principal functions of sterols in plant cells. Plant cell membranes are important sites of perception of environmental abiotic factors, therefore, it can be surmised that sterols may play an important role in the plant stress response. The aim of this review was to discuss the most representative trends in recent studies regarding the role of sterols in plant defense reactions to environmental factors, such as UV radiation, cold and drought stress. Some correlations were observed between changes in the sterol profile, referring to the ratios of individual compounds (including 24-methyl/ethyl sterols and sitosterol/stigmasterol) as well as the relative proportions of conjugated sterols (ASGs, SGs and SEs) and the nature of the stress response. Diversity of sterols and their conjugated forms may allow sessile plants to adapt to environmental stress conditions.

Age-related changes of cholestanol and lathosterol plasma concentrations: an explorative study

Background Cerebrotendinous xanthomatosis (CTX) and Lathosterolosis represent two treatable inherited disorders of cholesterol metabolism that are characterized by the accumulation of cholestanol and lathosterol, respectively. The age of the patients suspected of having these disorders is highly variable due to the very different phenotypes. The early diagnosis of these disorders is important because specific therapeutic treatment could prevent the disease progression. The biochemical diagnosis of these defects is generally performed analyzing the sterol profile. Since age-related levels of these sterols are lacking, this study aims to determine a preliminary comparison of plasma levels of cholestanol and lathosterol among Italian unaffected newborns, children and healthy adults. Methods The sterols were extracted from 130 plasma samples (24 newborns, 33 children and 73 adults) by a liquid-liquid separation method and quantified by gas chromatography coupled with a flame ionization detector. Results Cholesterol, cholestanol and lathosterol levels together with the cholestanol/cholesterol and lathosterol/cholesterol ratios are statistically different among the three groups. Cholesterol levels progressively increased from newborns to children and to adults, whereas cholestanol/cholesterol and cholestanol/lathosterol ratios progressively decreased from newborns to children and to adults. Lathosterol levels were higher in adults than in both newborns and children. In the total population a positive correlation was observed between cholesterol levels and both cholestanol (correlation coefficient = 0.290, p = 0.001) and lathosterol levels (correlation coefficient = 0.353, p < 0.0001). Conclusions Although this study can only be considered an explorative experience due to the low number of analyzed samples, we revealed several differences of plasma cholestanol and lathosterol levels and their ratios to cholesterol levels among newborns, children and adults. These evidences indicate the need of age-related reference values of cholestanol and lathosterol concentrations, including also newborns and children.