Evaluating glucose and xylose as cosubstrates for lipid accumulation and c-linolenic acid biosynthesis of Thamnidium elegans

Aims: To study the biotechnological production of lipids containing rich amounts of the medically and nutritionally important c-linolenic acid (GLA), during cultivation of the Zygomycetes Thamnidium elegans, on mixtures of glucose and xylose, abundant sugars of lignocellulosic biomass. Methods and Results: Glucose and xylose were utilized as carbon sources, solely or in mixtures, under nitrogen-limited conditions, in batch-flask or bioreactor cultures. On glucose, T. elegans produced 31.9 g/L of biomass containing 15.0 g/L lipid with significantly high GLA content (1014 mg/L). Xylose was proved to be an adequate substrate for growth and lipid production. Additionally, xylitol secretion occurred when xylose was utilized as carbon source, solely or in mixtures with glucose. Batch-bioreactor trials on glucose yielded satisfactory lipid production, with rapid substrate consumption rates. Analysis of intracellular lipids showed that the highest GLA content was observed in early stationary growth phase, while the phospholipid fraction was the most unsaturated fraction of T. elegans. Conclusions: Thamnidium elegans represents a promising fungus for the successful valorization of sugar-based lignocellulosic residues into microbial lipids of high nutritional and pharmaceutical interest.

Insulin receptor substrate-2 gene variants in subjects with metabolic syndrome: association with plasma fatty acid levels and insulin resistance

Several insulin receptor substrate-2 (IRS-2) polymorphisms have been studied in relation to insulin resistance and type 2 diabetes. To examine whether the genetic variability at the IRS-2 gene locus was associated with the degree of insulin resistance and plasma fatty acid levels in metabolic syndrome (MetS) subjects. Methods and results: Insulin sensitivity, insulin secretion, glucose effectiveness, plasma fatty acid composition and three IRS-2 tag-single nucleotide polymorphisms (SNPs) were determined in 452 MetS subjects. Among subjects with the lowest level of monounsaturated (MUFA) (below the median), the rs2289046 A/A genotype was associated with lower glucose effectiveness (p<0.038), higher fasting insulin concentrations (p<0.028) and higher HOMA IR (p<0.038) as compared to subjects carrying the minor G-allele (A/G and G/G). In contrast, among subjects with the highest level of MUFA (above the median), the A/A genotype was associated with lower fasting insulin concentrations and HOMA-IR, whereas individuals carrying the G allele and with the highest level of ω-3 polyunsaturated fatty acids (above the median) showed lower fasting insulin (p<0.01) and HOMA-IR (p<0.02) as compared with A/A subjects. Conclusion: The rs2289046 polymorphism at the IRS2 gene locus may influence insulin sensitivity by interacting with certain plasma fatty acids in MetS subjects.

Acid-base reactions between an acidic soil and plant residues

The elemental composition of residues of maize (Zea mays), sorghum (S. bicolor), groundnuts (Arachis hypogea), soya beans (Glycine max), leucaena (L. leucocephala), gliricidia (G. sepium), and sesbania (S. sesban) was determined as a basis for examining their alkalinity when incorporated into an acidic Zambian Ferralsol. Potential (ash) alkalinity, available alkalinity by titration to pH 4 and soluble alkalinity (16 It water extract titrated to pH 4) were measured. Potential alkalinity ranged from 3 73 (maize) to 1336 (groundnuts) mmol kg(-1) and was equivalent to the excess of their cation charge over inorganic anion charge. Available alkalinity was about half the potential alkalinity. Cations associated with organic anions are the source of alkalinity. About two thirds of the available alkalinity is soluble. Residue buffer curves were determined by titration with H2SO4 to pH 4. Soil buffer capacity measured by addition of NaOH was 12.9 mmol kg(-1) pH(-1). Soil and residue (10 g:0.25 g) were shaken in solution for 24 h and suspension pH values measured. Soil pH increased from 4.3 to between 4.6 (maize) and 5.2 (soyabean) and the amounts of acidity neutralized (calculated from the rise in pH and the soil buffer capacity) were between 3.9 and 11.5 mmol kg(-1), respectively. The apparent base contributions by the residues (calculated from the buffer curves and the fall in pH) ranged between 105 and 350 mmol kg(-1) of residue, equivalent to 2.6 and 8.8 mmol kg(-1) of soil, respectively. Therefore, in contact with soil acidity, more alkalinity becomes available than when in contact with H2SO4 solution. Available alkalinity (to pH 4) would be more than adequate to supply that which reacts with soil but soluble alkalinity would not. It was concluded that soil Al is able to displace cations associated with organic anions in the residues which are not displaced by H+, or that residue decomposition may have begun in the soil suspension releasing some of the non-available alkalinity. Soil and four of the residues were incubated for 100 days and changes in pH, NH4+ and NO3- concentrations measured. An acidity budget equated neutralized soil acidity with residue alkalinity and base or acid produced by N transformations. Most of the potential alkalinity of soyabean and leucaena had reacted after 14 days, but this only occurred after 100 days for gliricidia, and for maize only the available alkalinity reacted. For gliricidia and leucaena, residue alkalinity was primarily used to react with acidity produced by nitrification. Thus, the ability of residues to ameliorate acidity depends not only on their available and potential alkalinity but also on their potential to release mineral N. (C) 2004 Elsevier B.V. All rights reserved.

Nitrous acid: vibrational frequency shifts due to 15N substitution, and the harmonic force field

Vibration rotation spectra of HO15 NO and DO15 NO have been measured at a resolution of 0•04 cm-1 to determine the isotopic shifts in the vibrational band origins. These have been used together with recently determined data on the vibrational band origins, Coriolis constants, and centrifugal distorition constants, to determine the harmonic force field of both cis and trans nitrous acid in least squares refinement calculations. The results are discussed in relation to recent ab initio calculations, the inertia defects, and the torsional potential function.

Effects of dietary vitamin A concentration of roasted soybean inclusion on marbling, adipose cellularity, and fatty acid composition of beef

A feedlot trial was conducted to determine the effect of dietary vitamin A concentration and roasted soybean (SB) inclusion on carcass characteristics, adipose tissue cellularity, and muscle fatty acid composition. Angus-crossbred steers (n = 168; 295 +/- 1.8 kg) were allotted to 24 pens (7 steers each). Four treatments, in a 2 x 2 factorial arrangement, were investigated: no supplemental vitamin A, no roasted soybeans (NANS); no vitamin A, roasted SB (20% of the diet on a DM basis; NASB); with supplemental (2,700 IU/kg) vitamin A, no roasted SB (WANS); and with supplemental vitamin A, roasted SB (WASB). Diets included high moisture corn, 5% corn silage, 10 to 20% supplement, and 20% roasted SB in the SB treatments on a DM basis. The calculated vitamin A concentration in the basal diet was < 1,300 IU/kg of DM. Blood samples (2 steers/pen) were collected for serum vitamin A determination. Steers were slaughtered after 168 d on feed. Carcass characteristics and LM composition were determined. Fatty acid composition of LM was analyzed, and adipose cellularity in the i.m. and s.c. depots was determined. No vitamin A x SB interactions were detected (P > 0.10) for cattle performance, carcass composition, or muscle fatty acid composition. Low vitamin A diets (NA) did not affect (P > 0.05) ADG, DMI, or G:F. Quality grade tended (P = 0.07) to be greater in NA steers. Marbling scores and the percentage of carcasses grading > or = Choice(-) were 10% greater for NA steers, although these trends were not significant (P = 0.11 and 0.13, respectively). Backfat thickness and yield grade were not affected (P > 0.26) by vitamin A supplementation. Composition of the LM was not affected (P > 0.15) by vitamin A or SB supplementation. Serum retinol at slaughter was 44% lower (P < 0.01) for steers fed NA than for steers supplemented with vitamin A (23.0 vs. 41.1 microg/dL). A vitamin A x SB interaction occurred (P < 0.05) for adipose cellularity in the i.m. depot; when no SB was fed, vitamin A supplementation decreased cell density and increased cell size. However, when SB was fed, vitamin A supplementation did not affect adipose cellularity. Adipose cellularity at the s.c. depot was not affected (P > 0.18) by vitamin A or SB treatments. Fatty acid profile of the LM was not affected by vitamin A (P > 0.05), but SB increased (P < 0.05) PUFA (7.88 vs. 4.30 g/100 g). It was concluded that feeding NA tended to increase marbling without affecting back-fat and yield grade. It appeared that NA induced hyperplasia in the i.m. but not in the s.c. fat depot.

Effect of replacing calcium salts of palm oil distillate with extruded linseeds on milk fatty acid composition in Jersey and Holstein cows

Clinical and biomedical studies have provided evidence for the critical role of n-3 fatty acids on the reduction of chronic disease risk in humans, including cardiovascular disease. In the current experiment, the potential to enhance milk n-3 content in two breeds with inherent genetic differences in mammary lipogenesis and de novo fatty acid synthesis was examined using extruded linseeds. Six lactating cows (three Holstein and three Jersey) were used in a two-treatment switchback design with 3 × 21-day experimental periods to evaluate the effect of iso-energetic replacement of calcium salts of palm oil distillate (CPO) in the diet (34 g/kg dry matter (DM)) with 100 g/kg DM extruded linseeds (LIN). For both breeds, replacing CPO with LIN had no effect (P > 0.05) on DM intake or milk yield, but reduced (P < 0.05) milk fat and protein yield (on average, from 760 to 706 and 573 to 552 g/day, respectively). Relative to CPO, the LIN treatment reduced (P < 0.01) total saturated fatty acid content and enhanced (P < 0.001) 18:3n-3 in milk, whereas breed by diet interactions were significant for milk fat 16:0, total trans fatty acid and conjugated linoleic acid concentrations. Increases in 18:3n-3 intake derived from LIN in the diet were transferred into milk with a mean marginal transfer efficiency of 1.8%. Proportionate changes in milk fatty acid composition were greater in the Jersey, highlighting the importance of diet–genotype interactions on mammary lipogenesis. More extensive studies are required to determine the role of genotype on milk fat composition responses to oilseeds in the diet.

The photodimerisation of the alpha- and beta-forms of trans-cinnamic acid: a study of single crystals by vibrational microspectroscopy

Infrared and Raman microspectroscopy have been used to follow the photodimerisation reactions of single crystals, the alpha- and beta-forms of trans-cinnamic acid. This approach allows the starting materials and products -alpha-truxillic acid that has C-i symmetry and beta-truxinic acid, which has C-s symmetry-to be identified. It also allows the topotactic nature of the reaction to be confirmed. Attempts to produce the poorly-defined unreactive gamma-form of trans-cinnamic acid resulted only in a mixture of the alpha- and beta-forms. The findings suggest a wide role for these spectroscopic methods in monitoring solid-state organic reactions. (C) 2002 Elsevier Science B.V. All rights reserved.

Extraction and determination of ellagic acid content in chestnut bark and fruit

Chestnuts are an important economic resource in the chestnut growing regions, not only for the fruit, but also for the wood. The content of ellagic acid (EA), a naturally occurring inhibitor of carcinogenesis, was determined in chestnut fruits and bark. EA was extracted with methanol and free ellagic acid was determined by HPLC with UV detection, both in the crude extract and after hydrolysis. The concentration of EA was generally increased after hydrolysis due to the presence of ellagitannins in the crude extract. The concentration varied between 0.71 and 21.6 ing g(-1) (d.w.) in un-hydrolyzed samples, and between 2.83 and 18.4 mg g(-1) (d.w.) ill hydrolyzed samples. In chestnut fruits, traces of EA were present in the seed, with higher concentrations in the pellicle and pericarp. However, all fruit tissues had lower concentrations of EA than had the bark. The concentration of EA in the hydrolyzed samples showed a non-linear correlation with the concentration in the unhydrolyzed extracts. (C) 2008 Elsevier Ltd. All rights reserved.

Achievement of dietary fatty acid intakes in long-term controlled intervention studies: approach and methodology

Objective: To describe the calculations and approaches used to design experimental diets of differing saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) compositions for use in a long-term dietary intervention study, and to evaluate the degree to which the dietary targets were met. Design, setting and subjects: Fifty-one students living in a university hall of residence consumed a reference (SFA) diet for 8 weeks followed by either a moderate MUFA (MM) diet or a high MUFA (HM) diet for 16 weeks. The three diets were designed to differ only in their proportions of SFA and MUFA, while keeping total fat, polyunsaturated fatty acids (PUFA), trans-fatty acids, and the ratio of palmitic to stearic acid, and n-6 to n-3 PUFA, unchanged. Results: Using habitual diet records and a standardised database for food fatty acid compositions, a sequential process of theoretical fat substitutions enabled suitable fat sources for use in the three diets to be identified, and experimental margarines for baking, spreading and the manufacture of snack foods to be designed. The dietary intervention was largely successful in achieving the fatty acid targets of the three diets, although unintended differences between the original target and the analysed fatty acid composition of the experimental margarines resulted in a lower than anticipated MUFA intake on the HM diet, and a lower ratio of palmitic to stearic acid compared with the reference or MM diet. Conclusions: This study has revealed important theoretical considerations that should be taken into account when designing diets of specific fatty acid composition, as well as practical issues of implementation.

Dietary manipulation of fatty acid composition in lamb meat and its effect on the volatile aroma compounds of grilled lamb

The effect on lamb muscle of five dietary supplements high in polyunsaturated fatty acids (PUFA) was measured. The supplements were linseed oil, fish oil, protected lipid (high in linoleic acid (C18:2 n-6) and alpha-linolenic acid (C18:3 n-3)), fish oil/marine algae (1:1), and protected lipid/marine algae (1:1). Eicosapentaenoic acid (C20:5 n-3) and docosahexaenoic acid (C22:6 n-3) were found in the highest amounts in the meat from lambs fed diets containing algae. Meat from lambs fed protected lipid had the highest levels of C18:2 n-6 and C18:3 n-3, due to the effectiveness of the protection system. In grilled meat from these animals, volatile compounds derived from n-3 fatty acids were highest in the meat from the lambs fed the fish oil/algae diet, whereas compounds derived from n-6 fatty acids were highest in the meat from the lambs fed the protected lipid diet. (C) 2004 Elsevier Ltd. All rights reserved.

Classification of lactose and mandelic acid THz spectra using subspace and wavelet-packet algorithms

This work compares classification results of lactose, mandelic acid and dl-mandelic acid, obtained on the basis of their respective THz transients. The performance of three different pre-processing algorithms applied to the time-domain signatures obtained using a THz-transient spectrometer are contrasted by evaluating the classifier performance. A range of amplitudes of zero-mean white Gaussian noise are used to artificially degrade the signal-to-noise ratio of the time-domain signatures to generate the data sets that are presented to the classifier for both learning and validation purposes. This gradual degradation of interferograms by increasing the noise level is equivalent to performing measurements assuming a reduced integration time. Three signal processing algorithms were adopted for the evaluation of the complex insertion loss function of the samples under study; a) standard evaluation by ratioing the sample with the background spectra, b) a subspace identification algorithm and c) a novel wavelet-packet identification procedure. Within class and between class dispersion metrics are adopted for the three data sets. A discrimination metric evaluates how well the three classes can be distinguished within the frequency range 0. 1 - 1.0 THz using the above algorithms.

NOS3 gene polymorphisms are associated with risk markers of cardiovascular disease, and interact with omega-3 polyunsaturated fatty acids

Objective Omega-3 polyunsaturated fatty acids (n-3 PUFA) may protect against the development of cardiovascular disease (CVD). Genotype at key genes such as nitric oxide synthase (NOS3) may determine responsiveness to fatty acids. Gene–nutrient interactions may be important in modulating the development of CVD, particularly in high-risk individuals with the metabolic syndrome (MetS). Methods Biomarkers of CVD risk, plasma fatty acid composition, and NOS3 single nucleotide polymorphism (SNP) genotype (rs11771443, rs1800783, rs1800779, rs1799983, rs3918227, and rs743507) were determined in 450 individuals with the MetS from the LIPGENE dietary intervention cohort. The effect of dietary fat modification for 12 weeks on metabolic indices of the MetS was determined to understand potential NOS3 gene–nutrient interactions. Results Several markers of inflammation and dyslipidaemia were significantly different between the genotype groups. A significant gene–nutrient interaction was observed between the NOS3 rs1799983 SNP and plasma n-3 PUFA status on plasma triacylglycerol (TAG) concentrations. Minor allele carriers (AC + AA) showed an inverse association with significantly higher plasma TAG concentrations in those with low plasma n-3 PUFA status and vice versa but the major allele homozygotes (CC) did not. Following n-3 PUFA supplementation, plasma TAG concentrations of minor allele carriers of rs1799983 were considerably more responsive to changes in plasma n-3 PUFA, than major allele homozygotes. Conclusions Carriers of the minor allele at rs1799983 in NOS3 have plasma TAG concentrations which are more responsive to n-3 PUFA. This suggests that these individuals might show greater beneficial effects of n-3 PUFA consumption to reduce plasma TAG concentrations.

Eicosapentaenoic acid and docosahexaenoic acid from fish oils: differential associations with lipid responses

Fish-oil supplementation can reduce circulating triacylglycerol (TG) levels and cardiovascular risk. This study aimed to assess independent associations between changes in platelet eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and fasting and postprandial (PP) lipoprotein concentrations and LDL oxidation status, following fish-oil intervention. Fiftyfive mildly hypertriacylglycerolaemic (TG 1·5–4·0 mmol/l) men completed a double-blind placebo controlled cross over study, where individuals consumed 6 g fish oil (3 g EPA � DHA) or 6 g olive oil (placebo)/d for two 6-week intervention periods, with a 12-week wash-out period in between. Fish-oil intervention resulted in a significant increase in the platelet phospholipid EPA (+491 %, P,0·001) and DHA (+44 %, P,0·001) content and a significant decrease in the arachidonic acid (210 %, P,0·001) and g-linolenic acid (224 %, P,0·001) levels. A 30% increase in ex vivo LDL oxidation (P,0·001) was observed. In addition, fish oil resulted in a significant decrease in fasting and PP TG levels (P,0·001), PP non-esterified fatty acid (NEFA) levels, and in the percentage LDL as LDL-3 (P�0·040), and an increase in LDLcholesterol (P�0·027). In multivariate analysis, changes in platelet phospholipid DHA emerged as being independently associated with the rise in LDL-cholesterol, accounting for 16% of the variability in this outcome measure (P�0·030). In contrast, increases in platelet EPA were independently associated with the reductions in fasting (P�0·046) and PP TG (P�0·023), and PP NEFA (P�0·015), explaining 15–20% and 25% of the variability in response respectively. Increases in platelet EPA � DHA were independently and positively associated with the increase in LDL oxidation (P�0·011). EPA and DHA may have differential effects on plasma lipids in mildly hypertriacylglycerolaemic men.

Calpain-10 interacts with plasma saturated fatty acid concentrations to influence insulin resistance in individuals with the metabolic syndrome

Background: Calpain-10 protein (intracellular Ca2+-dependent cysteine protease) may play a role in glucose metabolism, pancreatic β cell function, and regulation of thermogenesis. Several CAPN10 polymorphic sites have been studied for their potential use as risk markers for type 2 diabetes and the metabolic syndrome (MetS). Fatty acids are key metabolic regulators that may interact with genetic factors and influence glucose metabolism. Objective: The objective was to examine whether the genetic variability at the CAPN10 gene locus is associated with the degree of insulin resistance and plasma fatty acid concentrations in subjects with MetS. Design: The insulin sensitivity index, glucose effectiveness, insulin resistance [homeostasis model assessment of insulin resistance (HOMA-IR)], insulin secretion (disposition index, acute insulin response, and HOMA of β cell function), plasma fatty acid composition, and 5 CAPN10 single nucleotide polymorphisms (SNPs) were determined in a cross-sectional analysis of 452 subjects with MetS participating in the LIPGENE dietary intervention cohort. Results: The rs2953171 SNP interacted with plasma total saturated fatty acid (SFA) concentrations, which were significantly associated with insulin sensitivity (P < 0.031 for fasting insulin, P < 0.028 for HOMA-IR, and P < 0.012 for glucose effectiveness). The G/G genotype was associated with lower fasting insulin concentrations, lower HOMA-IR, and higher glucose effectiveness in subjects with low SFA concentrations (below the median) than in subjects with the minor A allele (G/A and A/A). In contrast, subjects with the G/G allele with the highest SFA concentrations (above the median) had higher fasting insulin and HOMA-IR values and lower glucose effectiveness than did subjects with the A allele. Conclusion: The rs2953171 polymorphism at the CAPN10 gene locus may influence insulin sensitivity by interacting with the plasma fatty acid composition in subjects with MetS. This trial was registered at clinicaltrials.gov as NCT00429195.