High Amounts Of Carbohydrates Research Articles

Seasonal variations in the sediment biogenic properties of a tropical mangrove environment, southwest coast of India

Temporal and spatial changes in the sediment properties of a mangrove ecosystem (Cochin, southwest coast India) are presented. The region was freshwater dominated during monsoon (June–September) and seawater dominated during other two seasons. The system remained eutrophic due to the high inputs of organic matter (OM) during most part of the year. The organic-rich sediments accumulated high amount of carbohydrates (22% of OM) and proteins (11% of OM) during non-monsoon months as compared to coastal environments. Principal component analysis showed that the biochemical properties are uniformly influenced by seasonal and spatial variations. Higher concentrations of sediment protein over carbohydrate indicate an efficient mineralization leading to the non-availability of aged OM in the system. The dominance of these labile components is generally indicative of the eutrophic condition of the system.

Proximate Composition and Mineral Analysis of Cinnamon

A study was conducted to know the nutritive value of cinnamon in the Department of Huma n Nutrition, NWFP Agricultural University, Peshawar. The standard procedures of AOAC (2003) were followed to analyze the proximate composition and mineral analysis. The caloric value was calculated from crude protein, crude fat, crude fiber, carbohydrate, moisture and ash content. The iron (Fe), zinc (Zn), calcium (Ca), chromium (Cr), manganese (Mn) and magnesium (Mg) were determined by Atomic Absorption Spectrophotometer, sodium (Na) and potassium (K) by Flame Photometer and phosphorus (P) by Spectrophotometer. The results revealed that cinnamon contained ash (2.4%), crude protein (3.5%), crude fat (4%), crude fiber (33.0%), moisture (5.1%) and carbohydrate (52.0%). While the mineral determination gave the data that cinnamon contained iron (7.0 mg/g), Zinc (2.6 mg/g), Calcium (83.8 mg/g), Chromium (0.4 mg/g), Manganese (20.1 mg/g) and Magnesium (85.5 mg/g), sodium (0.0 mg/g), Potassium (134.7 mg/g) and Phosphorus (42.4 mg/g). This study concluded that the tested cinnamon contained highest amount of carbohydrate and lowest amount of ash. Similarly, among minerals the tested cinnamon contained highest amount of potassium and no sodium at all.

The influence of dietary fibre source and gender on the postprandial glucose and lipid response in healthy subjects

Consumption of soluble dietary fibre is correlated with decreased postprandial glucose and insulin responses and hence has beneficial effects on the metabolic syndrome. To investigate the effects on postprandial glucose, insulin and triglyceride concentrations of meals enriched with soluble dietary fibres from oats, rye bran, sugar beet fibre or a mixture of these three fibres. Thirteen healthy human volunteers (6 men and 7 women, aged 20-28 years) were included in the study. The subjects came to the study centre once a week after an overnight fast to ingest test meals and a control meal in random order. The meals contained either oat powder (62 g, of which 2.7 soluble fibre), rye bran (31 g, of which 1.7 g soluble fibre), sugar beet fibre (19 g, of which 5 g soluble fibre), a mixture of these three fibres (74 g, of which 1.7 g soluble fibre from each source, giving 5 g soluble fibre) or no added fibre (control) and were all adjusted to contain the same total amount of available carbohydrates. Blood samples were drawn before and every 30 min up to 180 min after the meals. Meals with rye bran gave a lower postprandial glucose peak when compared with the control meal, and this effect was more pronounced in women compared to men. Oat powder, containing a low amount of total fibre and a high amount of carbohydrates in liquid matrix, gave a higher incremental glucose peak concentration compared to rye bran and sugar beet fibre and higher insulin incremental area under curve compared to control. The oat powder also influenced the effects of the mixed meal, diminishing the glucose-lowering effects. Postprandial triglyceride levels tended to be higher after all fibre-rich meals, but only significant for oat powder and the mixed meal when compared with the control meal. Postprandial glucose, insulin and triglyceride concentrations are influenced by dietary fibre-rich meals, depending on fibre source, dose of soluble and total fibre and possibly gender.

Phytochemical and antimicrobial screening of extracts of Aquilaria agallocha Roxb.

Aquilaria agallocha Roxb. is an endangered economic plant used for production of agar wood worldwide. The aqueous and methanol extracts along with dry powder of leaf and bark of the plant was screened for the presence of phytochemicals. Also they were tested for antibacterial activity against pathogenic bacteria such as Shigella flexneri, Bacillus brevis, Pseudomonas aeruginosa and Bacillus subtilis. The result indicates the presence of alkaloids, anthroquinones, triterpenoids, tannins, fixed oils and fats and glycosides in methanol extracts whereas saponins, fixed oils and fats, alkaloids and triterpenoids were found in the aqueous extracts. The highest alkaloid content was in the aqueous extract of the bark (0.06%). The saponin content was found to be high in the leaf powder (0.169%). The bark powder contained 0.067% glycosides while the leaf powder had 0.036%. The leaf powder had the highest amount of carbohydrates (19.42 mg/g dry weight), protein (24.37 mg/g DW) and amino acids (12.1 mg/g DW). The methanol extract of the leaf gave the highest zone of inhibition against B. subtilis (19 mm). All other extracts showed moderate zones of inhibition (14 - 18 mm) against all the bacteria tested. The present study has proved the usefulness of agarwood tree for medicinal purposes. The presence of phytochemicals indicates its potential as a source of useful drugs.

Phytochemical and antimicrobial screening of extracts of Aquilaria agallocha Roxb.

Aquilaria agallocha Roxb. is an endangered economic plant used for production of agar wood worldwide. The aqueous and methanol extracts along with dry powder of leaf and bark of the plant was screened for the presence of phytochemicals. Also they were tested for antibacterial activity against pathogenic bacteria such as Shigella flexneri, Bacillus brevis, Pseudomonas aeruginosa and Bacillus subtilis. The result indicates the presence of alkaloids, anthroquinones, triterpenoids, tannins, fixed oils and fats and glycosides in methanol extracts whereas saponins, fixed oils and fats, alkaloids and triterpenoids were found in the aqueous extracts. The highest alkaloid content was in the aqueous extract of the bark (0.06%). The saponin content was found to be high in the leaf powder (0.169%). The bark powder contained 0.067% glycosides while the leaf powder had 0.036%. The leaf powder had the highest amount of carbohydrates (19.42 mg/g dry weight), protein (24.37 mg/g DW) and amino acids (12.1 mg/g DW). The methanol extract of the leaf gave the highest zone of inhibition against B. subtilis (19 mm). All other extracts showed moderate zones of inhibition (14 - 18 mm) against all the bacteria tested. The present study has proved the usefulness of agarwood tree for medicinal purposes. The presence of phytochemicals indicates its potential as a source of useful drugs.

Cropping system effects on carbohydrate content and water-stable aggregates in a calcareous soil of Central Iran

The effect of humus, readily decomposable organic matter, and carbohydrates of a nonspecific nature on the formation of water-stable aggregates in field rotation members of a calcareous soil in central Iran, Isfahan ( fine loamy mixed thermic typic haplargid) has been studied. The study was carried out at Lavark experimental farm in plots receiving 0 (T1), 25 (T2), 50 (T3) and 100 (T4) Mg/ha of manure for 5 years successively with a cropping rotation of wheat ( Triticum aestivum L.)–corn ( Zea mays L.) every year and plots under similar chemical fertilizer management but with three different cropping rotations (T5, T6 and T7) that has been the prevalent cropping systems. Three replications of soil sample in each treatment and at the depths of 0–5 and 5–15 cm were used to measure organic carbon (OC), hot-water-soluble carbohydrate, dilute acid hydrolysable carbohydrate, cold-water-soluble carbohydrate and mean weight diameter of water stable aggregates. The highest amount of carbohydrate (700 mg/kg) and aggregate stability (0.8 mm) were obtained in plots with 100 Mg/ha manure (T4). The amount of carbohydrate extracted from soil samples decreased in the order of hot water, dilute acid and cold water extracts. Aggregate stability had a better correlation with hot water ( r = 0.74**) and dilute acid-soluble carbohydrate ( r = 0.73**) than organic carbon ( r = 0.62**) content of soil. This indicates that the carbohydrate extracted by hot water and dilute acid may be a suitable indicator for showing soil quality, particularly in relation to soil aggregation.

“Wispino” protocol for 18FDG-PET scanning of myocardium

Dear Sir, Myocardial glucose kinetics is related with feeding state, insulin and free fatty acid levels and heart work [1, 2]. In the fasted state, the use of glucose accounts for approximately 30%, lactate for approximately 10% and free fatty acids for approximately 60–70% of the oxygen uptake of the myocardium. Conversely, after a high-carbohydrate meal when insulin concentrations are increased, the use of glucose accounts for approximately 70% and lactate for approximately 30% of the oxygen uptake of the myocardium [2]. Correspondingly, after carbohydrate load either orally or by means of glucose/insulin infusion, FDG should be taken up avidly by the myocardium. For FDG-PET imaging of myocardium, there are standard protocols which are more or less time consuming. In general, the patient should be in a fasting state and then receive a glucose load to stimulate the insulin secretion. Insulin application can be necessary in patients with very high glycaemia. In our department, we observed that many patients who were referred for oncologic PET studies often showed a high myocardial FDG uptake despite their fasting condition. To evaluate the possible effect of diet on this occurrence, we asked every patient about the dietary intake of the meal in the evening before the FDG-PET investigation. Interestingly, we found that patients who had a high myocardial FDG uptake had ingested a carbohydrate-rich meal in the evening. Based on this matter, we developed a new protocol named “Wispino” for our myocardium FDG-PET investigations. Wispino is the name of a popular menu in our hospital containing a big portion of potatoes, thus a high amount of carbohydrates. The patients are advised to have a meal with high-carbohydrate content the evening before the FDG-PET study and a piece of bread with jam approximately 2 h before the investigation. This protocol is less time consuming, more convenient for the patients and has been successfully used to increase myocardial FDG uptake in non-diabetic patients in our institution.

Chemical analysis and preliminary toxicological evaluation of Garcinia mangostana seeds and seed oil

The chemical analysis and preliminary toxicological evaluation of Garcinia mangostana seeds and seed oil have been investigated in order to determine the possibility of using them for human and/or animal consumption. Proximate analysis showed that the seeds had high amount of carbohydrate and were rich in oil (21.68 ± 6.18%) but have a low protein content. The physical properties of the oil extracts showed the state to be liquid at room temperature (25 ± 1 °C) and the colour of the oil golden-orange. The specific gravity of the oil was 0.98 ± 0.01. Among the chemical properties of the oil extracts, acid value, saponification number, iodine value, percent free fatty acid and peroxide value compared well with those of conventional edible oils. The seed flour was found to be a good source of minerals. It contained considerable amounts of potassium (7071 mg/kg), magnesium (865 mg/kg) and calcium (454 mg/kg). Fatty acid composition of the seed oil indicated that the oil contained one essential fatty acids small proportions: linoleic acid (1.30%). The most prevalent fatty acids were palmitic acid (49.5%) and oleic acid (34.0%). Weanling albino rats appeared to suffer no toxicological effects when fed with G. mangostana seed oil in their diet for 8 weeks. Weekly monitoring of the rats showed good physical appearance and steady weight increase. Histological examination of sections of the heart, liver, kidney, spleen and lung revealed that the kidney of some of the rats had some degrees of pathology which included diffuse glomerular and tubular degeneration. No lesion was found in the heart and liver of the rats. The seed oil could be useful as an edible oil and for industrial applications.

The effect of isolation method on the chemical structure of residual lignin

Two methods are used for the isolation of residual lignin: acidolytic and enzymatic hydrolysis. Recently a two-step procedure that is a combination of enzymatic and acidic hydrolyses was proposed. In this paper, the structures of residual lignins isolated by these three methods are compared. Enzymatic hydrolysis gave lignin with the highest yield (83%); however, it contained high amounts of carbohydrates and protein. The molar mass of enzymatic lignin was the highest, indicating that no cleavage of lignin occurred. Acidolysis gave a significantly lower lignin yield (40%), but this lignin was practically free from impurities. The β-aryl ether and lignin-carbohydrate linkages cleaved during the isolation, which was manifested in the decreased molar mass of the lignin as well as in increased phenolic hydroxyl group content. The new two-step isolation procedure gave properties between the preparations of enzymatic and acidolytic hydrolyses. The lignin yield was high (78%), but it contained some impurities, although less than the enzymatic lignin. The lignin-carbohydrate linkages cleaved to some extent, but the β-aryl ether linkages remained intact.

A Comparison of Low-Carbohydrate vs. High-Carbohydrate Diets: Energy Restriction, Nutrient Quality and Correlation to Body Mass Index

Objectives: To evaluate free-living adults’ diets that ranged from very low to high amounts of carbohydrate for their energy content, nutritional quality and correlation to Body Mass Index.Methods: Adults ages 19 years and older, who had complete dietary intake data on day-1 of the USDA’s 1994 to 1996 Continuing Survey of Food Intakes by Individuals (CSFII 1994–1996), were divided into four groups—very low, low, moderate and high carbohydrate—based on the percent total energy from carbohydrate. Mean energy, nutrient, food intakes and Body Mass Index values were compared among the groups. SUDAAN software package was used for the data analysis and pair-wise mean comparisons (p < 0.05).Results: The high-carbohydrate diet was lower in energy and energy density (number of kilocalories per gram of total amount of food consumed) than the other three diets. Macronutrient composition varied significantly among all the four groups. Nutrient density (amount of nutrient per 1,000 kilocalories of energy consumed) of vitamin A, carotene, vitamin C, folate, calcium, magnesium and iron increased and that of vitamin B12 and zinc decreased with an increase in the percent total energy from carbohydrate. The high-carbohydrate group ate more of low-fat foods, grain products and fruits. This group also had the lowest sodium intake. Adults eating a high-carbohydrate diet are more likely to have Body Mass Index values below 25.Conclusion: A study of diets of free-living adults in the U.S. showed that diets high in carbohydrate were both energy restrictive and nutritious and may be adopted for successful weight management.

Associations between dietary factors in canned food and formation of calcium oxalate uroliths in dogs

To identify dietary factors in commercially available canned foods associated with the development of calcium oxalate (CaOx) uroliths in dogs. 117 dogs with CaOx uroliths and 174 dogs without urinary tract disease. Case dogs were those that developed CaOx uroliths submitted to the Minnesota Urolith Center for quantitative analysis between 1990 and 1992 while fed a commercially available canned diet. Control dogs were those without urinary tract disease evaluated at the same veterinary hospital just prior to or immediately after each case dog. A content-validated multiple-choice questionnaire was mailed to each owner of case and control dogs with the permission of the primary care veterinarian. Univariate and multivariate logistic regressions for each dietary component were performed to test the hypothesis that a given factor was associated with CaOx urolith formation. Canned foods with the highest amount of protein, fat, calcium, phosphorus, magnesium, sodium, potassium, chloride, or moisture were associated with a decreased risk of CaOx urolith formation, compared with diets with the lowest amounts. In contrast, canned diets with the highest amount of carbohydrate were associated with an increased risk of CaOx urolith formation. Feeding canned diets formulated to contain high amounts of protein, fat, calcium, phosphorus, magnesium, sodium, potassium, chloride, and moisture and a low amount of carbohydrate may minimize the risk of CaOx urolith formation in dogs.

Glucidic determinants expressed by the digestive apparatus of Umbrina cirrosa (L.) fries as revealed by lectin histochemistry

Glycoconjugates present in the various parts of the digestive apparatus (oesophagus, stomach, intestine) of 27, 34 and 44 days-old Umbrina cirrosa (L.) fries were characterised by means of lectin histochemistry in conjunction with sialidase digestion and KOH treatment. High amounts of carbohydrates were detected especially in goblet cells of the oesophagus. Positivity obtained with the various lectins in oesophagus, stomach and intestine did not change during the development of the fries examined. D-Gal and D-GalNAc appeared to occupy a terminal position in oligosaccharidic chains whereas they are linked to sialic acid residues in adult subjects, which suggests an incomplete chemical structure of the glycoconjugates secreted by the digestive apparatus of fries.

Characteristics of Dissolved Organic Material in Total Chlorine Free Bleach Plant and Laboratory Effluents

The dissolved organic material present in totally chlorine free (TCF) pulp mill bleaching effluents and in their laboratory made counterparts was characterized using chemical and chromatographic analysis. Special attention was given to analysis of material originating from lignin and carbohydrate. With the exception of the P2 laboratory effluent, the BOD7, COD and TOC loads and the content of aromatic lignin in the effluents, were higher in the mill effluents. After oxygen stages, the content of monomeric acidic phenols and aromatic acids in the effluents was very low. The highest amount of carbohydrates was found dissolved in the first P stage mill effluent. The average molar mass of UV-absorbing material was lowest in ozone effluents. Carbohydrates were determined as monosaccharides after acid hydrolysis. Xylan was the main carbohydrate component in most effluents, and after ultrafiltration more xylose was found in fractions over 10 000 NMM. Ozone effluents were rich in arabinose, which was mostly found in fractions below 10 000 NMM. Most of the mannose and galactose that dissolved in the first alkaline peroxide stage effluents was found in fractions over 10 000 NMM.

Characteristics of dissolved organic material in total chlorine free bleach plant and laboratory effluents

The dissolved organic material present in totally chlorine free (TCF) pulp mill bleaching effluents and in their laboratory made counterparts was characterized using chemical and chromatographic analysis. Special attention was given to analysis of material originating from lignin and carbohydrate. With the exception of the P 2 laboratory effluent, the BOD 7 , COD and TOC loads and the content of aromatic lignin in the effluents, were higher in the mill effluents. After oxygen stages, the content of monomeric acidic phenols and aromatic acids in the effluents was very low. The highest amount of carbohydrates was found dissolved in the first P stage mill effluent. The average molar mass of UV-absorbing material was lowest in ozone effluents. Carbohydrates were determined as monosaccharides after acid hydrolysis. Xylan was the main carbohydrate component in most effluents, and after ultrafiltration more xylose was found in fractions over 10 000 NMM. Ozone effluents were rich in arabinose, which was mostly found in fractions below 10 000 NMM. Most of the mannose and galactose that dissolved in the first alkaline peroxide stage effluents was found in fractions over 10 000 NMM.

Estudo da composição química de flocos de cereais com ênfase nos teores de fenilalanina

The chemical composition and the amount of phenylalanine in 13 types of breakfast cereals produced in Brazil and marketed in Sao Paulo were studied. All products showed high amounts of carbohydrates, higher than 77%, supplying a minimum of 345 kcal/100g. The protein contents (Nx5.7) ranged from 3.8 to 7.3%. The phenylalanine levels varied between 224 and 451 mg/100g of the products and the lowest levels were detected in cereals with a reduced protein content, corresponding to cereal flakes with high sugar contents. The amino acid analysis revealed that phenylalanine accounted for 5.96±0.12 g/100g recovered amino acids, with no significant statistical differences among the 13 products studied and showed to be independent of the cereal type. It was possible to establish a linear correlation between the micro-Kjeldahl nitrogen and the phenylalanine level of the samples (correl. coeff. 0.9887) and consequently estimate the phenylalanine contents based only on a simple nitrogen analysis and multiplying the protein content by 5.96. The calculated phenylalanine contents in the 13 products did not differ statistically from the data obtained by amino acid analysis.

Dietary Carbohydrate and Fat Do Not Alter the Thyroid Response to Protein Deficiency in Chicks

Consumption of low-protein diets consistently causes elevations in circulating levels of triiodothyronine (T3) in several species of animals. In chicks this is often accompanied by lower levels of circulating thyroxine (T4). Since low-protein diets are usually formulated by replacing the detected protein with carbohydrate, the question arises as to whether the changes in thyroid hormones are a result of the lower protein or higher amounts of carbohydrate in such diets. Male broiler chicks, 13-26 days of age, were fed experimental diets that contained either an adequate level of protein (24%) or levels that were slightly (17%) or moderately (10%) deficient in protein. The deleted protein was replaced, isocalorically, with either glucose, soybean oil, or hydrogenated coconut fat. Though the level of protein and source of energy differed among diets, all diets contained identical amounts of all nutrients and energy, and were of similar weight densities. Circulating levels of thyroid hormones were measured from blood samples taken at the end of the study. Plasma T3 was elevated to a similar degree in all protein-deficient animals compared with control. Plasma T4 decreased in all protein-deficient chicks and was lowest with 10% dietary protein. Changes in circulating levels of thyroid hormones occurred independently of the source of dietary energy. Therefore, it is concluded that alterations in circulating levels of thyroid hormones that occur in chicks fed low-protein diets are a specific effect of the protein deficit and are not a related to the amounts of carbohydrate or fat present in the diet.

Use of the golden apple snail, cassava, and maize as feeds for the tiger shrimp, Penaeus monodon, in ponds

Penaeus monodon stocked in ponds at 8000/ha were fed four types of farm-made feeds starting on day 16 of a 4-month culture period. The feeds were golden apple snail alone or in combination with cooked cassava or maize, or maize only. Mixed feeds resulted in significantly higher production, growth, and better size-frequency distribution of shrimp. Survival (88–99%) was not significantly different among the treatments. Maize alone or snails alone were inadequate. Presumably, the high amount of carbohydrate in cassava (92%) or maize (87%) provided the needed energy, and the high protein content of golden snail (54%) was available for growth. The fatty acid profile of the golden snail shows that it is a good source of 18:2 n-6, 18:3 n-3, and 20:5 n-3 which are essential fatty acids for P. monodon. The golden snail, with an essential amino acid index (EAAI) of 0.84, is a useful alternative source of protein for tiger shrimp. Feeding shrimps with golden snails and cassava yielded the highest net income (P48797/ha-crop) and return on investment (ROI = 206%) better than feeding with maize alone (net income = P23190/ha-crop; ROI = 120%), an industry practice. If shrimp farmers use golden snails as direct feed or as a feed ingredient, the problem of snail infestation in ricefields may be reduced. Snails will no longer be viewed as pests but rather as a resource which has economic value.

Saponins, phytic acid, tannins and protease inhibitors in quinoa ( Chenopodium quinoa, Willd) seeds

The seeds of quinoa ( Chenopodium quinoa, Willd), a food crop of the Andean region of Latin America, contain protein of good quality and high amounts of carbohydrates, fat, vitamins, and minerals. An industrial process for manufacturing infant food using quinoa as a basic raw material is being developed. The presence of antinutrients are of importance in this context, and this paper deals with saponins, phytic acid, tannins and protease inhibitors in quinoa seeds. The samples of quinoa analysed in this experiment contained two main types of saponins. The amount of saponin A (β- d-glucopyranosyl -[β- d-glucopyranosyl -(1 → 3)-α- l -arabino- pyranosyl-(1 → 3)]-3-β-23- dihydroxy-12- en-28- oate methyl ester) was 0·7% of the dry weight and that of the saponin B (β- d-glucopyranosyl -[β- d-glucopyranosyl -(1 → 3)-α- l -arabino- pyranosyl-(1 → 3)]-3-β-23- dihydroxyolcan-12- en-28- oate was 0·2% of the dry weight. These were the major saponins found in the quinoa bran collected while polishing the seeds. After scrubbing and washing, the level of saponin-A remaining in the seeds decreased to 0·31% of the dry weight, and saponin-B was completely removed by this process. The content of phytic acid in the quinoa seeds was about 1% of the dry matter, and scrubbing and washing reduced the phytic acid content of the seeds by about 30%. Neither protease inhibitor nor tannins were detected in the quinoa seeds.

REGULATION OF SUCRASE-ISOMALTASE MESSANGER RNA CONCENTRATION IN RAT SMALL INTESTINE BY SUCROSE FEEDING

Sucrose feeding is known to induce increase of sucrase (S) and isomaltase (I) activities. In order to document the molecular process involved, we studied in rat, the regulation of the transcription of the corresponding mRNA in response to sucrose feeding. In this purpose, a cloned rat S-I probe has been prepared. By Northern hybridization in high stringent conditions, the cDNA sequence hybridizes to a single 6kb nucleotides species specific to the rat intestine. After 3 days of pre-feeding a carbohydrate free diet (cellulose diet, CD), rats were fed either with CD, either with a diet containing high amounts of carbohydrates (sucrose diet, SD). Animals were then killed at 0, lh30, 3h, 6h and 15h after refeeding, and a jejunal segment removed. In the mucosal homogenates, a significant increase in S and I activities (p < 0.05) occured only 3h after initiation of SD. Northern hybridization of equal amount of total jejunal RNA to rat S-I cDNA probe indicated that after lh30 of refeeding, SD rats had twice as much S-I mRNA as those on cellulose diet. This difference in S-I mRNA levels was maintained or increased at tha other experimental times. In contrast, hybridization with β-actin cDNA failed to show difference in the β-actin mRNA. The rapid production of SI mRNA provides convincing evidence that the carbohydrate stimulated rise of sucrase activity involved an increase of S-I gene expression at the transcriptional level, associated or not with a stabilization of the S-I messenger.

Composition of Neurospora crassa vacuolar membranes and comparison to endoplasmic reticulum, plasma membranes, and mitochondrial membranes

We have determined the carbohydrate and lipid contents of vacuolar membranes from Neurospora crassa, and have compared them to mitochondrial membranes, endoplasmic reticulum, and plasma membranes. These four membrane fractions were clearly distinct from each other in polypeptide composition, as judged by polyacrylamide gel electrophoresis. The vacuolar membranes proved unusual in two respects: the contained very high amounts of carbohydrate and were the only membranes with significant levels of phosphatidylserine. As in other eucaryotic cells, the mitochondrial membranes were unique in having high amounts of cardiolipin but virtually no sterol. Although the endoplasmic reticulum and plasma membranes were qualitatively similar to each other, the plasma membranes could be distinguished by a higher carbohydrate content, whereas the endoplasmic reticulum had a characteristically high ratio of phosphatidylcholine to phosphatidylethanolamine. The fatty acid compositions of all four membranes were similar, except that mitochondrial membranes contained about half as much saturated fatty acids as the other three fractions.